CERNAVODA PROBABILISTIC SAFETY EVALUATION Archive/1995_JULY 3... · ROMANIAN ELECTRICAL POWER...
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ROMANIAN ELECTRICAL POWER AUTHORITY f ijl I. CERNAVODA PROBABILISTIC SAFETY EVALUATION CPSE PHASE В V >i A PSA Level 1 Study SUMMARY REPORT ■i •b Prepared for IAEA IPERS mission 3 to 14 July, 1995 Bucharest, ROMANIA • ■ -7«..... : ' . ........... -.................... ... ■ ........... t ~ L;_
Transcript of CERNAVODA PROBABILISTIC SAFETY EVALUATION Archive/1995_JULY 3... · ROMANIAN ELECTRICAL POWER...
ROMANIAN ELECTRICAL POWER AUTHORITY
fijlI.
CERNAVODAPROBABILISTIC SAFETY EVALUATION
CPSE PHASE В
V >i
A PSA Level 1 Study
SUMMARY REPORT■i
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Prepared for IAEA IPERS mission 3 to 14 July, 1995
Bucharest, ROMANIA
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SUMMARY RETORT
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CONTENTS
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1. INTRODUCTION.....................................................................................................................................................1-1
1.2 Scope of the study.............................................................................................................................................. 1-21.3 Project organization and management..............................................................................................................1-41.4 Major tasks of CPSE Study...............................................................................................................................1-51.5 Organization of CPSE Phase В Summary Report...........................................................................................1-6
2. RESULTS OF THE ANALYSIS............................................................................................................................ 2-1
3. RESULTS OF THE IMPORTANCE AND SENSITTVITY ANALYSIS........................................................... 3-1
4. INTERPRETATION OF RESULTS, CONCLUSIONS AND RECOMMENDATIONS..................................4-1
5. OVERVIEW OF PROCEDURES AND METHODS............ ...............................................................................5-1
5.1 Project co-ordination......................................................................................................................................... 5-15.2 Initiating events selection..................................................................................................................................5-25.3 Plant damage states definition.......................................................................................................................... 5-35.4 Event tree analysis..............................................................................................................................................5-35.5 Fault tree analysis...............................................................................................................................................5-45.6 Human errors modelling....................................................................................................................................5-45.7 Accident sequence quantification......................................................................................................................5-55.8 Implementation, validation and running of computer codes..........................................................................5-55.9 Uncertainty analysis............................................................................ 5-65.10 Preparation of documentation.........................................................................................................................5-6
6. ORGANIZATION OF CPSE - PHASE В EXTERNAL DOCUMENTATION.................................................6-1
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1. INTRODUCTION
1.1 Background and objectives of the study
In the jjear 1986 a IAEA mission was conducted in Romania to initiate a PSA (Probabilistic Safety Assessment) and reliability program for Cemavoda NPP project. In 1988 a limited scope Level 1 PSA (CPSE - Phase A) was started, carried out mainly by the Institute for Nuclear Research (INR) - Pitesti team, with a limited participation of the designer group,
comprising 9 Event Trees and 17 Fault Trees, had as main objectives, the following:
- training of the PSA team in PSA methodology and techniques;- development of a PSA model for the plant, to be used for:
- plant design evaluation and, whenever applicable, safety improvements;- identification of scenarios for training of plant operators and development of
emergency procedures;- development of Technical Specifications;- development of specifications for a Living PSA.
The CPSE - Phase A has been supported, from the beginning, by the IAEA through expert missions, workshops, PSA reference documents and computer equipment and was the subject of an IAEA International Peer Review Service (IPERS) mission in October 1990, under-taken within the ROM/9/003 project as part of the IAEA Regular Program of Technical Cooperation. The IPERS mission provided valuable conclusions and detailed recommendations to be followed and implemented, focusing on the following areas:
• initiating event analysis;• accident sequence analysis;• system analysis;• component data;• treatment of dependencies and human interactions;• documentation and result presentations;• quality assurance
Afterwards a few single expert missions were conducted to support the implementation of the IPERS recommendation. PSA team members undertook fellowship training in the areas of
-plant-responserplant-systemanalysis^nd-PSA-methodology-andtechniques,---------------------- —
Since 1990, the Romanian Safety Authority (CNCAN) adopted specific approach on using PSA methods for the Cemavoda NPP Unit 1 as a licensing documentation.
After the first exercise of PSA methods implementation ( represented by CPSE - Phase A), and based on IAEA IPERS mission conclusions and recommendations and CNCAN specific approach on using PSA methods, CPSE Study restarted in 1993 as a fiill scope Level 1 PSA, known as CPSE - Phase B, whose main objectives are (see RENEL-GEN document MG- 01/07-ÈPSN-000, Act.2):
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• to provide a thorough safety design verification of the Cemavoda NPP Unit 1 design using probabilistic methods and to identify the most effective areas for improvement;
• to identify those initiating events and accident sequences that dominate the total core melt frequency and have the main contribution to the different plant damage states considered;
• to provide a comprehensive and realistic information base for the preparation of operating procedures and for the training of operating personnel in handling accident situations.
Coordinated by RENEL, Safety and Licensing Compliance and performed by an enlarged PSA team, including CITON Bucharest - Magurele and ICN - Pitesti, this new phase of the study benefited by IAEA assistance under ROM/9/008 Technical Cooperation Project. An IAEA
(CNCAN), was conducted during the period 31 October to 3 November 1994 under ROM/4/017 project. The purpose of the mission was to discuss the status of the present version (Phase B) of CPSE Study and reliability work, future steps in the area of PSA and also issues connected with the cooperation of the RENEL PSA and reliability groups at Bucharest, Pitesti and Cemavoda (see IPERS for the CPSE - Phase B, Final Report of the Pre-Review, 31 October to 3 November 1994).
Initially considered as a licensing documentation (see CNCAN Letter No.17962/11.10.1991), CPSE - Phase В is at present a prerequisite for Cemavoda NPP Unit 1 relicensing after the initial IS months of operation and Cemavoda NPP Unit 2 commissioning license. In the same time, CPSE - Phase В study will be used as a support documentation in the review and assessment activities for Reliability Analysis (RA) and Safety Design Matrices (SDM), to be issued for licensing the Cemavoda NPP Unit 1 (see CNCAN Letters No. 16253/27.04.1994, 16293/05.05.1995).
On the longer term a complete PSA study Level 1,2 & 3 is intended to be performed. It is also planned that the study is to be extended for internal fires and floods, for external events and initiating events associated with the D2 О tower, spent fuel bay, radioactive waste management facilities and fueling machine (F/M), as provided in RENEL Quality Assurance Manual (MG- 01/07-EPSN-000, Act.2).
1.2 Scope of the study
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The scope of a Level 1 PSA can be described mainly in terms of the foDowing parameters (see IAEA Report No.50-P-4 - Procedures for Conducting PSA of NPP, Level 1):
(i) potential sources of radioactive releases;
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(iii) initiating events;
(iv) core damage states;
For CPSE- Phase В Study, the examination of the above parameters is presented below.
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(i) Potential sources of radioactive releases
CPSE-Phase В confines to the following main sources of radioactive releases:
• reactor core and heat transport system;• moderator system (calandria vessel)
which represent the largest potential of radiological risk for the population, in case of accidental release.
The following potential sources of radioactive releases are not included yet in the performed CPSE Study:
• D2 Out• spent fbel bay components;• radioactive wastes management station components;
fueling machine (F/M) components.
These potential sources will be taken into account in a later stage of CPSE Study,
(ii) Plant operational states
Like the most PSA studies performed to date in the world, CPSE-Phase В Study considers only one plant operational state at the moment of the initiating event occurrence, namely that of nominal full power, with the reactor core at equilibrium.
(iii) Initiating events tÿ ;
In the CPSE-Phase В Study, the initiating events under consideration were those internal plant failures that could lead directly, or in combination with other failures, to damage to reactor fuel within containment. Initiating events outside the scope of CPSE Study were those associated with external events: both natural (e.g., earthquakes) and man-made (e.g., aircraft, crash), failures involving D2 О upgrading tower, spent fiiel bay, radioactive waste management station and fueling machine (F/M) and internal station flooding and fires. The external events, fires and flooding were excluded because the station safety analysis already incorporated through deterministic studies of these phenomena, which are also difficult to treat probabilistically. The remaining events were excluded mainly because they were judged not to have the potential for significant consequences. The list and grouping of the 34 initiating events analyzed in CPSE - Phase В are presented in Section 3.2 and 3.5 of the Main Report.
(iv) Core damage states .............. ................................ ......... ......... ..... .. ..
In order to differentiate between levels of severity of damage and consequences, different core damage-categories-arwellas-successfulendstatea weredefined: Theentirerspectrum~of core' damage accidents has been divided into a manageable set of 13 plant damage states (PDSO to PDS 12) in which each core damage accident can be placed, based on general fuel cooling characteristics associated with each individual sequence of events. The upper bound of the spectrum is represented by events that can lead to a loss of core structural integrity (i.e.: PDSO, PDS1, PDS2). The lower bound of the spectrum is represented by a loss of moderator fluid to containment, followed by a corresponding release of tritium or a LOCA without fuel failure showing a release of activity from the coolant (i.e.: PDS 10, PDS11; PDS 12). The set of PDS’s defined also includes separate states (PDS3, PDS4) for moderator availability as a heat
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sink, (with SGs pressurized or not). All of these PDS, excepting PDS5 -f PDS8 are used in CPSE - Phase B.
The successful end states in CPSE - Phase В Study (designed by OK) incorporates the various states of HTS cooldown with the HTS pumps, thermosyphoning or SDCS.
1.3 Project organization and management
The CPSE - Phase В organization and management conforms to the requirements contained in the RENEL - document “Quality Assurance Manual Probabilistic Nuclear Safety Evaluation”, code Nífcr-01 /07-ЕР SN-000, Rev. 2. .
The CPSE - Phase В was performed by a special complex group - “probabilistic safetyКЗЙorganizations:
• Romanian Power Authority - Nuclear Objectives Department (RENEL-GEN);• Institute for Nuclear Research (ICN) Pitesti;• Center of Technology and Engineering for Nuclear Projects (CITON) -
Bucharest, the former Institute for Power Studies and Design - Nuclear Department (ISPE-DN).
Three major groups are defining the organization structure of the CPSE group:
• the co-ordination group (CG);• the internal review group (GRI);• the working group.
The co-ordination group (CG) is composed of senior and working level representatives of the participating institutions (RENEL-GEN, ICN, CITON), is chaired by the CG head and has the responsibility to ensure the project general co-ordination and, in the same time, the interface with the third parties.
The internal review group (GRI) consists, as CG above, of representatives of all of the participating institutions (RENEL-GEN), ICN, CITON), the working level representatives having a greater extent participation. The GRI reports directly to the CG, is chaired by the GRI head and has the responsibility to ensure the project technical co-ordination and, in the same time, the internal review of the project, according to IAEA requirements for this type of activity.
The working group is composed of two CPSE teams:
• CITON - Bucharest - Magurele team, numbering 8 members• ICN - Pitesti team, numbering 13 members;
The CITON team was responsible for those tasks involving initiating events selection and grouping, plant damage states definition, headings definition and event trees development.
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The ICN team was responsible for the tasks involving the fault tree analysis for plant systems (front-line systems and support systems), integration of system models into an overall plant model and the generation of accident sequences and their quantification.
1.4 Major tasks of CPSE Study
The entire performance activity of the CPSE - Phase В Study involved a number of 10 major procedural steps, as described in RENEL - GEN document MG-01/07-EPSN-000, Rev. 2.
These are as follows:
- project co-ordination;~ - initiating events selection; ..... ~ ~ ’
- fuel damage categories definition;- event tree analysis;- fault tree analysis;- human errors modeling;- integration of fault tree / event tree and event sequence quantification;- implementation, validation and running of computer code;- uncertainty analysis;- preparation of documentation (final report).
a) Project co-ordination included the actions and activities necessary for the organization and management of the study as : the selection of methods and procedures, the selection and organization of team that perform the study, the training of the team, the preparation of project schedule, the estimation of necessary funds and the establishment of quality assurance manual.
b) Initiating events selection in CPSE Phase В is based on reference to existing lists: Darlington Probabilistic Safety Evaluation (DPSE) and Kema Study (Point Lepreau PSA Study). A list of 34 initiating events is analyzed in CPSE Phase B, grouped into the following 3 categories, according to their effect on the plant (see section A3 of the Main Report):
- transients (21 events);- loss of coolant accidents from PHTS (7 events);- loss of moderator and end shield cooling (6 events).
Initiating event frequencies are mainly based on fault tree analyses and on actual operating foreign experience for CANDU reactors.
c) Fuel damage categories used in CPSE Phase В are 13 PDS (PDSÖ ч- PDS12), each one representing a collection of event sequences judged to have similar characteristics with respect to accident progression. These PDS are defined in section 5.2 of this report and in Appendix A section A.4.1.2 of the Main Report. The 5 successful end states used in CPSE Phase В (see section 1.2), which incorporate the various states of PHTS cooldown with PHTS pumps, thermosyphoning or SDCS, are defined by OK.
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d) Event tree analyzed in CPSE Phase В are developed for all 34 initiating events selected above. The approach used in CPSE-Phase В is: “small event trees - large fault trees” ( support systems are not explicitly presented in the event trees, excepting electric power supply and back-up cooling)- see Section 5 of the Summary Report and Section 4.1 of the Main Report. Also, as the event trees display as headings safety functions and systems status, the event trees are of fimctional/systemic type. The results of this step in the performance process of CPSE Phase В are presented in Appendix A of the Main Report.
e) Fault tree analyzed in CPSE Phase В are 33, developed for 32 plant systems, including front line systems and support systems (see section 3.3 of the Main Report). The corresponding reports, presented in Appendix В section B.l -г B.33 of the Main Report contain fault tree logic development for all top events defined for each system, fault tree labeling and fault tree quantification.
f) Human errors modeling used in CPSE Phase В is based on Swain method. The event trees developed, generally do not include recovery human actions . The recovery human action are taken into account in the integration process. Human errors modeling is presented more detailed in section 4.3.
g) Integration of fault tree / event tree and event sequence quantification .The detailed description of the integration process for CPSE-Phase В Study, including the inputs .methods, products and the computer codes used in the analysis, is presented in section 6 of the Main Report and in section 5 of the Summary Report. The results of event sequence quantification are discussed in sections 2 and 3 of the Summary Report and section 6 of the Main Report.
h) Implementation, validation and running of computer code . The detailed information concerning the computer code package used in CPSE Phase В Study are provided in section 6.6 of the Main Report.
i) Uncertainty analysis is not yet performed for CPSE Phase В Study. This will become available at a later stage.
j) Preparation of documentation ffinal reportV In accordance with IAEA recommendations, CPSE Phase В documentation’s is divided into 3 major parts:
- summary report ;- main report;- appendices to the main report.
For more details concerning the organization of the documentation, see Summary Report, Section 6 ¿nd Main Report, Section 1.6.
1.5 Organization of CPSE Phase В Summary Report
CPSE Phàse В Summary Report consist of the following sections:
1. Introduction2. Results of the analysis:
- estimations of the core damage frequency, with relative contributions from the various initiators and the categories of PDS;
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- a list of dominant sequences;- a short description of the dominant accident sequences;
3. Results of the importance and sensitivity analyses, including:
- the relative contribution of initiating event with respect to core damage frequency;- the relative contribution of individual sequences to the core damage frequency;- the relative importance of basic events (human errors included) with respect to the
core damage frequency;
V4. Interpretation of results, conclusions and recommendations
5. Overview of methods
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2. RESULTS OF THE ANALYSIS
The results of CPSE -B accident sequence quantification process are presented in Tables 2-1 and 2-2 and figures 2. l-r2.6.
VThe information presented refer to dominant event sequences (for each PDS) representing 114 sequences of the total of 1043 quantified sequences. For these sequences, the recovery factors (as recommended in “Procedures for Conducting Probabilistic Safety Assessments of Nuclear
procedures and time available for operator action to mitigate the effect of the event.
Table 2-1 and fig. 2.1+2.6 present PDSs-Initiating Event contributions (frequencies and percent).
Loss of Service Water initiating event (see Appendix A, Section A4.6.3 of the Main Report for details) is the dominant one for late core damage (52 % - PDS1 and 75.5 % for PDS2).Very small LOCA (LOCA 1) and small LOCA (LOCA 2) - see section A4.2. of the Main Report) are dominant in the sequences ending by moderator as ultimate heat sink (PSD3 and PDS 4 respectively). Referring to PDS 9, 10, 11,12 only the sequences leading directly to each of these PDS have been considered from recovery factor point of view.
The sequences contributions to each PDS are presented in Table 2-1.
Significant implicants of these dominant sequences are presented more detailed in Table 2-2. The consequences on the plant state and the recovery fector used for each implicant (human erors included) are also presented in Table 2-2 :
L PDS1 dominant sequences are:
LI) LSW__ 19 (33.07%), meaning:
-loss of service water followed by:-reactor shutdown;
----- rClass-IV available;----- :— — -------------------------------------------------- --- --loss of backup cooling (and loss of Instrument Air, consequently) ;-loss of secondary circuit as heat sink;:lôsSQfgQ’^ëprësaïfi'sâtiolïXEWScanT'sûpplÿSGs)"
This sequence, described in section A4.6.3. of the Main Report, is presented with significant implicants in Table 2-2 (pos.I.l).
Back-up cooling valves (71690 -PV 1001 , -PV 103) failed closed and respectively open in dormant state are the main contributors of these sequences (see Table 2-2). These valves have been considered non tested. The influence of these valves testing is analyzed in Section 3 (Table 3-3).
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L2) LOCA1 5 (21.16%) meaning:
- very small LOCA (no LOCA signal), followed by :- reactor shutdown ;- class IV available ;- loss of PHIS make-up (assured by Pressure and Inventory Control
System);- loss of manual crash cooldown (ECCS cannot assure PHTS make-up); i loss of moderator as ultimate heat sink.
This sequence, described in Section A4.2 of the Main Report is presented with significant
The main contributors are the feed valves and moderator temperature control valves failed closed during mission.
1.3) TLOIA15 (13.3%), meaning:
- total loss of Instrument Air followed by :- reactor shutdown;- loss of class IV power supply after reactor trip;- loss of secondary circuit as heat sink;- loss of shutdown cooling system;- loss of SG’s depressurization (EWS cannot supply SGs);- loss of moderator as heat sink.
This sequence, described in Section A4.6.4. of the Main Report is presented, with significant implicante in Table 2-2, pos.1.3. 95% of this sequence frequency is due to operator error to block MSSVs in open position, 2 hours after loss of Instrument Air (leading to loss of secondary circuit as heat sink and loss of SG’s depressurization) and to shut moderator TCVs (63210-TCV6, -TCV8), to avoid RCW pumps trip (leading to loss of SDCS or moderator as heat sink). PDS1 contribution of this sequence has been reduced taking into account the operator possibility to recover class IV within two hours (see Table 2-2, pos. 1.3, MCS No.O, column 5).
П PDS2 dominant sequences are:
n.í) LSW_~15 (30.55%), meaning: .....
-------------loss-of-service-water-followed%^—----------------------- ----------------- ------------ ------------- reactor shutdown;- loss of class IV after reactor trip;- loss of SGs as heat sink supplied by EWS.
This sequence, described in Section A4.6.3 of the Main Report, is presented with significant implicants in Table 2-2, pos.II. 1. Failures in EWS system or no operator action to initiate EWS in pump mode, with class HI available, (non-procedured action) are the dominant basic events.
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П.2) LSW__ 27 (20.29%), meaning:
- loss of service water followed by:- reactor shutdown;- class IV available;- loss of back-up cooling (loss of Instrument Air one hour after loss of service water
and back-up cooling);- loss of secondary circuit as heat япк;
, - loss of SGs as heat sink, supplied by EWS.
This sequence, described in Section A.4.6.3 of the Main Report, is presented, with significant implicants in Table 2-2 (pos.n.l.).
Valves 71690-PV1001,-PV103 of Back-up Cooling System, failed closed , respectively open, in dormant, are the dominant basic events. The influence of these valves testing is analyzed in Section 3 (Table 3-3).
HI PDS3 dominant sequences are:
Ш.1) LOCAI 4 (55.7%), meaning:
- very small LOCA (no LOCA signal) followed by:- reactor shutdown;- class IV available;- loss of PHTS make-up assured by PIC;- loss of manual crash cooldown (ECCS cannot supply PHTS make-up).
Mechanical failure for feed valves and MSSVs are the dominant basic events of this sequence, described in Section A.4.2 of the Main Report and presented, with significant implicants, in Table 2-2 (pos. Ш.1).
Ш.2) LOCAI 27 (31.98%), meaning:
- very small LOCA (no LOCA signal) followed by:- reactor shutdown;- loss of class IV following reactor trip;- PIC available for about 1 hour;
_______ - loss of manual crash cooldown (ECCS cannot supply PHTS make-up). ..................
Mechanical failure of MSSVs or human error in manual crash cooldown are the dominant basic~events~of^his-sequencerdescribed-Tn-section-Ar4-.2-of-the-Main-Report-arid-presented,-with significfant implicants in Table 2-2 (pos.ni.2).
IV PDS4 dominant sequences are:
IV.l) LOCA2 16 (41.12%), meaning:
- small LOCA (LOCA signal) followed by:- reactor shutdown:
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- class IV available;- crash cooldown available;- loss of ECCS to assure the broken loop cooling.
Mechanical failures in ECCS system (HX plug, overpressure protection valves spuriously closed or internal leaks) or human error in ECCS - Low Pressure Injection (LP) initiation are the major contributors for this sequence frequency. The sequence, described in Section A.4.2 of the Main Report, is presented, with significant implicants, in Table 2-2 (pos.IV.l).
IV.2) LOCAI11, meaning:
- very small LOCA (no LOCA signal), followed by:- reactor shutdown;
- loss ofPHTS make-up (assured by PIC);- manual crash cooldown available;- loss of ECCS to assure PHTS make-up.
Mechanical failures in PIC (feed valves fail to operate during mission) and ECCS (HX plug, HX isolating or by-pass valves left in wrong position after test) are the dominant basic events. This sequence, described in Section A.4.2 of the Main Report, is presented, with significant implicants, in Table 2-2 (posTV.2).
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Table 2-1 PDS - I/E and Seq. Contributions (only sequences with recovery) ’
PDS1
FSD__ FSD__3 2.10E-07 0.0464%
Total IE 2.10E-07 0.0464%
HTPT_ HTPT_4 4.20E-08 0.0093%
Total IE 4.20E-08 0.0093%
LCUV LCLIV3 8.04E-07 0.1777%
LMIIS LMIIS3 4.42E-08 0.0098%
Total IE 4.42E-08 0.0098%
LOCA1 LOCAIS 9.57E-05 21.1577%LOCA1 LOCA128 5.07E-05 11.2025%LOCA1 LOCA131 2.69E-06 0.5936%LOCA1 LOCAIS 9.34E-07 0.2065%
Total IE 1.50E-04 33.1603%
LOCA2 LOCA28 2.71 E-06 0.5985%
Total IE 2.71E-06 0.5985%
LSW LSW 19 1.50E-04 33.0743%LSW_ LSW 2 5.21E-05 11.5241%LSW_ LSW 1 2.94E-05 6.5064%LSW LSW 21 3.28E-06 0.7258%LSW LSW 4 6.12E-07 0.1352%LSW_ LSW_20 1.11E-07 0.0246%
Total IE 2.36E-04 51.9903%
PCL PCL 6 1.87E-06 0.4125%PCL PCL 9 9.34E-07 0.2065%PCL__ PCL__19 1.84E-07 0.0407%
Total IE -2.$9Е-0в 0.6598%
TLOIA TLOIA15 6.Q2E-05 13.3050%
Total IE 6.02E-06 13.3050%
TT TT 11 1.9SE-07 0.0430%
Total IE 1Л6Е-07 0.0430%
Total PDS1 4.S2E-04
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PDS10
LMC
LMF
PDS11
LMIL
LMC__1
TotalC
LMF__1
TotalE
Total PDS10
LMIL_0
Totals
4.31 E-06
4.31 E-06
3.60E-05
3.60E-06
4.03E-06
4.00E-05
4.00E-05
10.7050%
10.7050%
89.2950%
89.2950%
100.0000%
100.0000%
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PDS12
LMIIS
PDS2
LMIIS0 5.90E-01 100.0000%
Totals 5.90E-01 100.0000%
Total PDS« 6.90E-01
1MSSO 1MSS016 3.12E-07 0.1359%
Totals 3.12E-07 0.1359%
FSD FSD 11 1.88E-06 0.8183%FSD FSD 16 1.54E-07 0.0672%FSD_ FSD_6 8.91 E-08 0.0388%
Totals 2.12E-06 0.9244%
HTPT_ HTPT_22 3.75E-07 0.1637%
Totals 3.75E-07 0.1637%
LCLIV LCLIV42 2.28E-06 0.9957%LCLIV LCLIV10 1.41 E-06 0.6164%
Totals 3.70E-06 1.6121%
LCV__ LCV__IIS 4.64E-07 0.2023%
Totals 4.64E-07 0.2023%
-4EHC -J FHC-4fM 1 nnPJVÎ п^юж«.
Totals 1.08E-06 0.4695%
LMIIS LMIIS9 1.46E-06 0.6381%LMIIS LMIIS12 6.08E-07 . 0.2651%
Totals 2.07E-06 0.9031%
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PDS2*
Total IE
Total PDS2*
1.04E-07
1.04E-07
LOCA1 LOCA112 3.35E-06 1.4611%LOCA1 LOCA141 Z69E-06 1.1751%LOCA1 LOCAIS 7.81 E-07 0.3404%LOCA1 LOCAI 48 6.09E-07 0.2654%LOCA1 LOCA117 8.07E-07 0.2647%LOCA1 LOCAI 70 3.70E-08 0.0161%LOCA1 LOCA134 9.75E-09 0.00«%
Total IE 8.09E-00 3.6271%
LOCA2 LOCA217 1.34E-05 5.8254%LOCA2 LOCA252 1.25E-06 0.5465%LOCA2 LOCA240 3.31 E-07 0.1441%LOCA2 LOCA236 2.75E-07 0.1198%
Total IE 1.52E-0S 9.6359%
LOCA3 LOCA315 4.84E-07 0.2109%
LOCAI LOCAI16 2.92E-06 1.2717%LOCAI LOCAI30 2.03E-07 0.0883%
Total IE 3.12E-06 1.3601%
LSW LSW IS 7.01 E-05 30.5546%LSW LSW 27 4.65E-05 20.2911%LSW LSW 12 2.86E-05 124769%LSW LSW 25 Z48E-05 10.7999%LSW LSW 31 2.67E-06 1.1659%LSW_ LSW_29 5.48E-07 0.2390%
Total IE 1.73E-04 76.6273%
PCL PCL 16 Z96E-06 12897%PCL PCL 23 8.11 E-07 0.2665%PCL__ PCL 33 5.12E-08 0.0223%PCL__ PCL__38 9.95E-09 0.0043%
Total IE 3.63E-06 1.6829%
SSLIC SSUC34 4.59E-07 02003%
Total IE ' 4.59E-07 02003%
TLOIA TLOIA17 1.16E-05 5.0645%
Total IE 1.19E-05 62646%
TT TT 153 1.97E-06 0.8609%TT TT 168 1.19E-06 0.5206%TT TT 144 1.43E-07 0.0624%TT TT 29 8.23E-08 0.0359%
Total IE 3.39E-09 14799%
Total PDS2 2.29E-04
SGTR SGTR 28 5.31 E-08 50.9808%SGTR_ SGTR_82 5.10E-08 49.0192%
100.0000%
RENEL - CPSE PHASE В - July 1995 - : Page S ' Î7Ï
SUMMARY RETORT
PDS3
4
PDS4
LCLIV LCUV29 3.50E-07 0.0249%
Total IE 3.50E-07 0.0249%
L0CA1 LOCA14 7.84E-04 55.7014%L0CA1 LOCA127 4.50E-04 31.9841%L0CA1 LOCA17 1.14E-05 0.8139%L0CA1 LOCA130 1.05E-06 0.0746%
Total IE 1.26E-03 88.6739%
L0CA2 LOCA27 2.05E-05 1.4551%
Total IE 2.0SE-06 14661%
PCL__ PCL 5 5.72E-05 4.0693%-ecu., a.
PCL_ PCL__18 2.86E-06 "“^^35%
Total IE 7.16E-06 6.0866%
TLOIA TL0IA14 6.84E-05 4.8595%
Total IE 6.84E-06 4.8696%
Total P0S3 1.41E-03
1MSSO 1MSS015 1.31E-05 1.0466%
Total IE 1.31E-06 1.0468%
DCCF_ DCCF_26 1.22E-06 0.0973%
Total IE 1.22E-06 0.0973%
PSD PSD 10 6.94E-06 0.5541%PSD__ PSD__15 2.88E-06 0.2304%
Total IE 9.82E-06 0.7846%
HTPT_ HTPT_35 5.89E-07 0.0471%
Total IE 6.89E-07 0.0471%
LCLIV LCUV41 1.11E-04 8.8318%
Total IE 1.11E-04 84318%
LCV_ _ ........... -LCV_124........................ 1.94E-05____ — -..... .1.5463%-
Total IE 1.94E-06 1.6463%
~TEffC_ LEHCJ03 4.49EJ05 375865%"
Total IE 4.49E-05 ■■ 3.6885%
LOCA1 LOCA111 2.38E-04 18.9995%LOCA1 LOCA140 1.26E-04 10.0497%LOCA1 LOCA147 1.06E-05 0.8446%LOCA1 LOCA116 5.O0E-O6 0.4055%
Total IE 3.79E-04 30.2994%
J^i®L,zXTSE.PHASEÄ-Iuly lä95^„.. J. • PageS. 2-8
SUMMARY RETORT
L0CA2 LOCA216 5.15E-04 41.1208%L0CA2 LOCA239 257E-05 2.0560%L0CA2 LOCA235 1.40E-06 0.1118%L0CA2 LOCA251 1.44E-08 0.0011%
Total IE 6.42E-04 43.2898%
LOCAS LOCA314 7.64E-06 0.6101%
Total IE 7.64E-06 0.8101%
LOCAI LOCA115 6.39E-05 5.1026%
VTotal IE 6.39E-06 6.1020%
PCL PCL 15 1.53E-05 1.2197%PCL PCL 22 1.15E-05 0.9187%PCL__ PCL__32 7.69E-07 0.0614%
TLF__ TLF_15 9.68E-06 0.7733%
Total IE 9.68Е-0в 0.7733%
TLOIA TL0IA16 1.08E-05 0.8617%
Total IE 1.08E-06 0.8817%
TT TT 152 6.66E-06 0.5317%TT TT 143 2.68E-06 0.2140%TT___ TT 167 2.20E-06 0.1755%
Total IE 1.1SE-0S 0.8211%
Total PDS4 1.25E-03
PDS4*
SGTR_ SGTR_50 8.79E-08 - 100.0000%
Total IE 8.79E-08 100.0000%
Total PDS4* 8.79E-08
PDS9
LOCA1 LOCA110 8.30E-03 32.3392%LOCA1 LOCAI 26 5.00E-03 19.4888%LOCAI LOCA115 1.00E-04 0.3898%
Total IE 1.34E-02 62Í2178%
LOCA2 LOCA26 1.00E-02 38.9776%
Total IE 1.00E-02 38.9776%
LOCAS LOCA36 1.00E-04 0.3898%
Total IE 1.00E-04 0.3898%
LOCAI LOCAI7 1.00E-03 3.8978%
Total IE 1.00E-03 3:8978%
■г-t
г»-.
RENEL - CPSEPHASE~Brnfflÿl995 ■PageS:~2-9
SUMMARY REPORT
LSW_ LSW_22 5.59E-04 2.1784%
Total IE 6.69E-04 2.1784%
PCL PCL 14 5.00E-04 1.9489%PCL__ PCL__21 1.00E-04 0.3898%
Total IE 6.00E-04 2.3387%
Total PDS9 2.67E-02
P0S9* V
SGTR SGTR 69 1.19E-06 92.2217%SGTR_ SGTR JO 1.00E-06 7.7783%
Total PDS9* 1.29E-0S
TOTAL 6.19E-01
I
t
î;
RENEL^CESE JHASILB.rJuly 19.95.. Page S.2JQ-.
H
SUMMARY КЕЮКТ
TABLE 2-2.
EXAMPLES
L Plant Damage
OF DOMINANT IMPLICANTS OF DOMINANT ACCIDENT SEQUENCES RESULTED Щ CPSE - PHASE В
State PDS1 -4.52E-04/y
LI LSW__19 = LSW_*RSD5_3*CLIV*L0CAPREV*MCRSU*N(BC_IV)*N(BPC4MA11)*N(SGD_LIA) I 1.496492 E-04 /у (Ref.A.4.6.3)
MCSNo. 183.658298E-05 /у
Recovery factor = 0.01 г (one procedure: “Loss of Instrument Air", time: >60 min.)- see Safety Series No. 50-P-4
imin! Basic Event Definition i DescriptionLossoi back-upicooling /71690//PV/1001/Q/FCCO/
(Ref.B.32)
«
Valve on Back-up cooling pump: discharge line to the users - fai close in dormant.
PV1001 is a normal closed valve, considered non tested - PV1001 fail closed in dormant - Back-up cooling is lost - IA compressors are lost 1 h after I/E.
Lossoi as a he
secondai»sink
i
i
i»
ty Circuit■
O/CTP///ODP/HE/(Ref.B.20)
No operator action to assure AidEjectors steam supply from the Auxiliary Steam Boiler.
No operator action to block in opeij
CSDV’s are lost in few hours due to loss of Condenser Air Extraction System, lost due to loss of steam supply to Air Ejectors. HE is considered 0.23 (action not procedured).
i)
i
/36110/MSSV/BLOKED//ODL/HE/ (Ref.B.18) position 1/16 MSSV, once it is
open - unavailable.
MSSV’s actuation is lost 3h after I/E (Ih after LSW and loss of back-up cooling IA compressors are lost and 2h after, the MSSV’s local air tanks are lost). HE is considered 1 (local action).
LossoiGeneradepress
Steam i torsurization
/36110/MSSV/BLOKED//ODL/HË/ (Ref.B.18)
No operator action to block in open position 1/16 MSSV, once it is| open -unavailable. |
Cross link failure between loss of secondary circuit and loss of SG depressurization.
RFNFI. . fPSE PHASE В . Iiilv 1094 Ряае S -1.11
»•,ï
ц
SUMMARY REPORT
MCS 1 Functioü Basic Event Definition DescriptionNo. 213.658298E-05 /у
Loss of
1t
/71690//P V/ ЮЗ/Q/FOOC/(Ref.B.32)
Valve on Back-up cooling pumps to ; secondary circuit line - fail to close [
,1
\
PV103 is normal open and and is considered a non tested valve. PV103 fail to close -
; diverted ftàw to the secondary circuit - loss of Back-up cooling - loss of IA compressors after 1 h.
Recoveiy factor = 0.01 (one procedure: “Loss of InstrumentAir” time: >60 min).- see Safety Series No. 50-P-4
Loos of circuit a
secondary s a heat sinkIi
j
i1
i*
/43210//PMP/05/OPPR/HE/
I
No operator action to assure the [<Deaerator supply by Auxiliary iCondensate Pump and Deaerator level control. |
t
Loss of Service Water - loss of Main Condensate Pumps - the operator action to start Auxiliary Condensate Pump is necessary. Also, loss of IA after loss of service water made unavailable the Deaerator level control and the operator must make it.HE for these actions (not usual) is considered1.
Loss of ias a heqj
Secondary circuit j sinki
/36110/MSSV/BLOCKED//ODL/HE/ (Ref. B. 18) ‘
No operator action to block in open position 1/16 MSSV, once it is open - unavailable.
MSSV’s actuation is lost 3h after I/E (Ih after LS Wand loss ofback-up cooling IA
■ compressors are lost and 2h after, theMSSV’s local air tanks are lost). HE is considered 1 (local action).
■ Loss of SteamGeneratorsdepressurization
/36110/MSS V/BLORED/ZOPL/HE/ (Ref.B.18)
No operator action to block in open ■ position 1/16 MSSV, once it is open - unavailable.
Cross link failure between loss of secondary circuit and loss of SG depressurization.
L2. LOCAIS = LpCAl*RSDl_3*CLIV^N(PIC_RMIY),*NíCCDM)*N(MC4EOCAM) - 9.573076E-05/у (fjef.A.4.2)
MCS Function ' Basic Event Definition DcscriptonNo. 111.076923E-05
Loss ofPflnrS make-up (assured hy Pressure & Inventory ControlSystem) !
/63331//LCV/12/N/FCO/(Ref.B.7)
Level control valve on feed line - fail to operate during mission time.
LCV12 fail to operate - low make-up flow inPHTS (< leakage rate).
No recovery factor(mechanicalfailures)
Loss of manual crash cooldowft' (no LOCA signal ip pase of very small LOCA)
///MED/PROB-MAN/COMB//(Ref.B.18)
Combination of MSSV’s -7/16MSSV’s fail to open (mechanical failure)
Crash cooldown unavailable^ ECCS injection can’t be initiated.
i1
RBNBL » CPSE PHASE В - Д ly 1995 Page S. 2-12
SUMMARY REPORT
Loss of ultímate
: noderator as heat sink in case
of LOCA
U. TLOIA15 = TLOIA*RSD3_l*N(CLIV)*CLUI$N(BPC3A9)*N(SDC3LIA)*N(SGD_LIA)*N(MCIIILIA) - б|)20022Е-057 y (Ref.A.4.6.4)
/63210//TCV/8/N/FCOO/ (Ref.B. 10)
Temperature control valve (large one) on Moderator System - fail to operate during mission time.
ass of Moderator cooling - moderator not |ubcooled, as it is necessary in case of LOCA •
erator unavailable as ultimate heat sink.
MCS Function Basic Event Definition DescriptonNo. 05.68175E-05/y
Loss of ^lass IV power supply
//CL. IV///// (Ref.B.25)
CLIV power supply is lost after reactor trip.
Rec. factor 0.Ó05- 0.5- cl.IV recovery within 2 h after loss of IA (when MSSV local air tanks are exhausted emptied); PHTS cooldown is assured by SDCS/ Moderator;- 0.01- (one procedure:“Loss of Instrument Air”; time > 60 min)- see Safety SeriesNo. 50-P-4
Loss of asahea:
¡econdary circuit sink
Loss of Sdepressuri:
Gzation j
/36110/MSS V/BLOKED/ODL/HE/ (Ref.B. 18)/36110/MSS V/BLOKED/ODIÆE/ (Ref.B. 18)
No operator action to block in open position 1/16 MSSV, once it is open.
CLIV is lost - cl.ni is established. If cl.IV power supply is reestablished until exhausting of MSSV’s local air tanks (2 h after I/E), 3 RCW pumps are available to assure SDCS/ Moderator system cooling and operator action to close Moderator TCV’s (63210-TCV-6 and 8) is not necessary.
No operator action to block in open position 1/16 MSSV, once it is open.]
MSSV’s actuation is lost 2h after I/E. HE is considered 1 (local action).Cross link failure between loss of secondary circuit and loss of SG depressurization.
(SDCS) Systems RCW sj
Loss of Shutdown Cooling !
/32110/TCV//ODL/HE/ (Ref.B.29)
Moderator (due to loss of stem) j
No operator action to close Moderator’s Temperature Control Valves (63210-TCV-6 and -TCV-8) which are failed open due to I/E.
In case of loss of Instrument Air (IA) and class IV, the operator action is necessary to close within 1 h 32110-TCV-6 and -TCV-8, to avoid trip of RCW pumps on high flow and, consequential loss of SDCS and Moderator Systems HE is considered 1 (local action).
RENEL - CPSE PHASE В - July 1995 Page S. 2-13
I t mtli 41
I
SUMMARY RETORTI; tI !
IL PLANT DAMAQR STATE fDS2 A=2.29E-04/y
IL I. LSW_!5 = LS\V_íRSD5_3^N(CLIV)*CUBC_3*MCRSU*SQP_LSW*N(EWDTEWP2) - 7.006539E-05 / y (Ref.A.4.6.3)I. i
MCS Function Basic Event Definition DescriptionNo. 2 Loss of CLIV power //CLIV///// Loss of CLIV power supply after, CLIV recovery within 24 h does not affect1.897958Е-05/У supply (Ref.B.25) reactor trip.
\the sequence development, as SteamGenerators supply by Emergency WaterSupply System from Dousing Tank is unavailable.
No recovery Loss pf Steam /34610//PY/7/T/IfCC/ 34610-PV7 - air operated isolating Steam Generatory water supply from Dousingfactor (only mechanical failure, without cUY power sunnlv recovery)
Generators as heat sink supplied by Emergency Wafer Supply System • (EVyS)
(Ref.B.24) valve fail closed. Tank and from the river (by EWS pumps) is unavailable.
No. 0 Los? pf class iy power //CLIV///// Loss of class IV power supply after CLIV can be recovered within 24 h, becauseL7SÊ188E-05/y
Recovery factor: 0.005:• 0.05 - operator decision to initiate Steam (generators supply by BWS within30 tnin- (from SecondaryControl room), with dill available.- see Safety Series No. 50-P-4
supply
. 1
. ii ‘ii
i
i
(Ref.B.25)
i
reactor trip.
«
Steam Generators water supply can be assured from Dousing Tank.
i ; j
, !
RENEL - CPSE PHASE B ^uly 1995i i
Page S. 2-14
J•
,'
SUMMARY REPORT
1s
>
■.
« •1
! ,■ Г
1.! : .
-0.1 г class IV power recovery within 24h (SteamGenerators are supplied by EWS from Dousing Tank)
Loss of Genera supplie«
Steam orsashe l by EWS
at sink,i
/ÆPS-EWS/START//ODS/HE/(Ref.B.27)
No operator action to initiate EWS jin pumped mode (EPS included), f
In case of loss of class IV after loss of service water, operator must decide to initiate EWS in pumped mode, although class ni power supply is available. HE is considered 0.25, as this decisión is not an usual one (no black-out conditions) and EWS initiation is not an easy operation.
П.2. LSW__27 =LS)
Г fl! 'S
V__*RSD5_3*CLrV*LOCAPREV*MCRSU*N(BC_rV)*N(BPC4MAll)*SGD LlA*N(EW|)TEWP2). 4.652988E-05 / y (Ref.A.4.6.3)
MCS Functiob Basic Event Definition I Description
i ,:V i ■
No. 27 Lobs ofi ,
back-upcooling П1690//PV/1001/Q/FCCO/(RBf,B,32)
Valve on Back-up cooling pumps 1discharge line to the users - ftil l close in dormant. $
PV1001 is a normal closed valve, considered non tested - PV1001 hail closed in dormant « Back-up cooling is lost • IA compressors are lost 1 h.after I/E.
i!.. . i '
:
¡ I1
Recovery factor: 0.01 (one procedure: “Loss of InstrumentAir” time: > 60 min.- see Safety Series NO.50-P-4
Loss of as heat
secondary circuit rink 1
i
/43230//FCV/119/ODM/HE/ (Ref.B.13)
No operator action to control the 1flow on Auxiliary Feedwater Pump 1 (AFWP) line. [
One hour after loss of Instnunent Air (2 hours after loss) of Service water (LSW) and loss of back-up cooling (BCW). LCV’s and FCV-119 on Steam Generators feedwater supply lines lose their local air tanks. All these valves are fail open. Operator action to control AFWP flow by FCV-119 handwheel is necessary to maintain the pump in operation. HE is considered 1 (local action).
1
/O/CTP///ODP/HE/(Ref.B. 19)
No operator action to assure Air Ejectors steam supply from the Auxiliary Steam Boiler.
CSDV's are lost in few hours due to loss of condenser Air Extraction System, lost due to loss of steam supply to Air Ejectors. HE is considered 2.5E-1 (action not procedured).
ÎiiilJ
/43220//V/507/ODM/HE/(Ref.B. 14)
No operator action to open by-pass valve V-507, on Condensser - Condensate Storage Tank (CST) line.
As 43220-LCV104#2, on Condensser - CST line, is fail closed (due to loss of InstrumentAir after LSW and loss of BCW, the operator action to open its by-pass valve (43220-V507) is necessary to assure Main Feedwater Pumps supply from CST. HE is considered 1 (local).
i i. i
1
t
i
i
RENEL - CPSE PHASE B - Ju ly 1995 !!
}
i
ii
*.
Page S. 2-15 \
' »...
i!!1
ti
L - -WWW
SUMMARY REPORT
Loss of S General
team ¡il ors as heat sink,
supplied by EWS
IIL PLANT DAMAC г
IIL1. LOCA14 = LOÇ
//EPS-EWS/START//ODS/HE/(Ref.B.27)
No operator decision to initiate EWS in pumped mode (EPS included).
In case of loss of Service Water and BCW (loss of IA consequential), the operator must decide to initiate EWS in pumped mode, although dass IV power supply is available. HE is considered 0.2S, as this descision is not an usual one (no black-out conditions) and EWS initiation is not an easy operation.
ESTATE PDS3 1.51E-03/y
A1 *RSDl_3*CLIV*N(PIC_RMrV)*N(CCDM)*MC4LOCAM - 7.835407 E-04 / у (Ref.Aj4.2)
MCS Functio i ! Basic Event Definition 1 DescriptionNo. 61.442914E-07/y Recovery factor: 0.01- common cause failure for 7/16 MSSV’s
Loss of by Presi Control
PHTS make-up (assured ure and inventory - PIC System)
i
/63331//LCV/11/N/FCO/(Ref.B.7)
63331-LCV11 - level controi valveon feed line - fail to operate during mission time. 1
63331-LCV11 - fail to operate - low make-up flow in PHTS (< leakage rate).
Loss of manual prash cooldowniÍI1
/36110//PS V//CCF/FCCC/(Ref. B. 18)
Common cause failure for MSSV’s. In case of a very small LOCA manual crash cooldown is necessary to permit ECCS initiation (no LOCA signal in case of a very small LOCA). If 7/16 MSSV’s fail to open crash cooldown is unavailable.
RENEL - CPSE PHASE В - Jqly 1995 ! Page S. 2-16
■ • •••- 'Jin' l'MWM
¡
Ш.2. LOCA127 = L¿CAl*RSDl_3*N(CLIV)*CLni*PPC*BPC3Al*N(CCDM)*MC3LOCAM 4.49914 E-04 (lief. A.4.2)
SUMMARY REPORT ¡ . !--- ----------------------------------- i S .
MCS Fundi ?n 1 Basic Event Definition 1 DescriptionNo. 12.50E-05/y
Recoyeiy factor: 0.01- one procedure (“Small LOCA”) time: > 60 min.- see Safety Series No.SO-P-4
Lossol cl.IV power supply //CLIV/////(Ref.B.25)
Loss of class IV power supply afterreader trip. 1
CUV recovery doesn’t affect the sequences development.
Lossol ' manual crash cooldownj
1i
/34320/HP/20/LOCA1/RDP/HE/(Ref.A.6)
No operator action to make ]cooldown.
|rash In case of a very small LOCA manual crash cooldown is necessary to permit ECCS initiation (no LOCA signal in case of a very small LOCA). As PIC is available during about 1 h after I/E, the operator has about 1 h to make crash cooldown. HE is considered0.05 (skilled, from Main Control Room, in stress condition).
IV. PLANT DAMAC
rV.l LOCA216 = L(
i n! fiESTATE PDS 4 1.24E-03/y 1
(CA2*RSDl_l*LI*CLIV*BPC4MA12*CCD*N(ECC2_iy)AMC4LOCA - 5.147649 E-04 (ijjef. A.4.2)
MCS Fundirh : Basic Event Definition 1 DescriptionNo. 75.0870 lTE-05/yNo recovery factor(mechanicalfailure)
Lossolbroken
ECCS to assure the loop cooling
j-iij
/34320//HX/1/N/LO/(Ref.B.3)
ECCS HX is plugging durir mission time.
ECCS HX plugged -low flow in Low Pressure (LP) - loss of broken loop cooling.
No. 69.999998E-o7/y Recovery factor: 0.01- one procedure (“Large LOCA”) time: > 60 min.- see Safety Series NO.50-P-4
Lossolbroken
ECCS to assure the loop cooling
I
i1
/34320//LP/LOCA2/RDP/HE/(Ref.A.6)
1
No operator action to initiât]Low Pressure.
ECCS In case of small LOCA the operator action to initiate ECCS Low Pressure (220 min. afterI/E) is necessary, ensuring the broken loop cooling during mission time.
RENEL - CPSE PHASE В - Inly 1995 j
f
Л i. -T;
2-17
% J:
Page S.
SUMMARY REPORT
IV. 2. LOCA111 = L( )CA1*R SDl_3*CLIV*N(PIC_RMIV)*CCDM*N(ECCIVOA)*MC4LOCAM - 2.378419 E-( 4/у (Ref. A 4.2)
MCS Functioa ! . Basic Event Definition DescriptionNo. 226.9576 lE-06/yNo recoveiy factor(mechanicalfailure)
Loss of by Press System)
’HTSmi ure and I
' ;
ike-up (assuredinventory (PIC)
f
/63331//LCV/12/N/FCO/(Ref.B.7)
63331-LCV12 - level control on feed line - fail to operate < mission time.
valveuring
Feed valve fails to operate - low make-up flow in PHTS (< leakage rate).
Loss of make-u]
ÏCCS to»
j
assure PHTS¡ii
/34320//CV/76/T/IL/(Ref.B.3)
34320-CV-76-NO tested chec valve - internal leak. !
The effect of CV-76 internal leak is the diverted flow from ECCS HP to MP - the whole ECCS becomes unavailable.
i
RENEL - CPSE PHASE В - July 1993 PageS. 2-18
%|,li . r-ч
TLOIA
Figure 2.1 - l/E Contributions to PDS1 (only seq. with recovery)
ilаi i .til-, *
tt_lçli\4_oca12% 2% 4o/o
LOÖAIIo/
LSW_77%
ure 2.3 - l/E ContributionsS2 (only seq. with recovery)
I
Figure 2.4 - l/E
tloialcliv 5% 0%
LOCA21%
Contributions toPDS3 (only seq. with |recovery) LOCA1
89%
I
LOGA239%
LOCAI LOCA34%
0%
lsw2cl- 2% 2%
Figure 2.6 - l/E Contributions to PDS9 (only seq. with recove!
LOCAI53%
%
SUMMARY RETORT
3. RESULTS OF THE IMPORTANCE AND SENSITIVITY ANALYSIS
Refering to I/E importance in PDS, it is presented in Tables 3-1 (all sequences without recovery) and 3-2 (all sequences with recovery factor included). The results are very sensitive to recovery factor:
- LSW represent 98% of PDS1 frequency (without recovery); with recovery LSW importance in PDS 1 becomes 41.5%.
- LSW represent 88.6% of PDS2 frequency (without recovery) and 42.2% (with recovery);
- TLOIA represent 78.9% of PDS3 frequency (without recovery) and 4.1% (with recovery), while LOCA1, which represent 14.2% (without recovery), becomes 83.6% (with recovery);
- LOCA1 represent 26.7% of PDS4 frequency (without recovery) and 25.6% (with recovery), while LOCA2 represan 20.8% (without recovery) and 21.2% ( with recovery).
Refering to PDS9 to PDS12 this importance analysis is not concludent, as the recovery factors have been applied only to the sequences leading to these PDS on the shortest way.
Refering to test sensitivity of the results, PDS1 and PDS2 frequency was estimated, considering that Back-up cooling valves 71690-PV-1001 and -PV103, whichare basic events with a great contribution in PDS1 and PDS2 dominant sequences (LSW__19,LSW__1, LSW__27), are monthly tested (in the results presented in Section these valveshave been considered nonnested).
Comparing these results with those presented in Table 2-1, the following remarks must be done:
- frequency of these three sequences is about 10 times smaller;- PDS 1 total frequency is reduced from 4.52E-04 to 3.05E-04;
----- —PDS2 total-frequency is reduced from 2.29E-04 to 1.86E-04:--------------- ----------- -------
The following importances analyses were done:
- Risk Achievement Worth;- Risk Reduction Worth;- Fussel -Vesely Importance.
These analyses, represented in Figures 3.1 to 3.12 were done for PDS1 to PDS4 sequences. Only sequences with recovery factor were considoed.
RENEE - CPSEPHASE В - Jffly 1995" - ~ ....... 1 ----- ----------- ----------------------:-----Page'S^!
SUMMARY REEKT
;;:y ■1■I
The follKtog remarks have to be done:
-®H)S1 sequences, MSSVs failure in closed position (due to their mechanical failures or hunsieoor in blocking them in open position after loss of Instrument Air) are the main risk contifcors;
«FDS2 sequences, the main contributor are the operator initiation of EWS in conditiasof Cl.IV or С1.Ш availability ( no black-out conditions), when this action is not procedure«!;
®PDS3 sequences, MSSVs mechanical failures in closed position are the maincontributor;
•ffiPDS4 sequences, operator initiation of EWS in no black-out conditions is the main contrihtar.
For all PDS sequences, loss of class IV after reactor trip is a very important contributor.
.Æ: ■- .
"RENEES CFSKWSE B'- July Шэ ; •-* Page S. 3-2- ........; ; ■
SUMMARY REPORT
Table 3-1 Initiating Events Contributions ( all sequences included, no recovery)
PDS1
swaxnscæzsso:
DCCF 4.82E-06 0.0005%ELR 7.22E-06 0.0007%FSD 1.07E-04 0.0106%FWHF 3.33E-08 0.0003%HTPT 2.16E-06 0.0021%LCLIV 4.16E-04 0.0407%LCV 4.39E-0S 0.0004%LEHC_ 1.02E-06 0.0010%LESC1 3.62E-06 0.0004%LESC2 4.64E-07 0.0000%LFIC2 3.99E-08 0.0000%LMC__ 3.66E-08 0.0000%LMF 2.90E-07 0.0000%LMIIS 2.66E-06 0.0026%LMIL 1.73E-09 0.0000%
^J-DCAI . 1А2Еда..,-^.^.____ __—0.0066%LÖCA2 * 6.69E-0S
LOCA3 6.66E-07 0.0001%LOCAI 1.10E-00 0.0001%LSW__ 1.01E+00 98.4298%PCL 6.16E-04 0.0602%RPE 1.16E-06 0.0001%SRVSO 1.28E-08 0.0000%SSLIC 3.73E-06 0.0004%TLF 2.79E-07 0.0000%TLOIA , 1.32E-02 1.2939%TT 1.07E-04 0.0104%
Total PDS1 1.02E+00
PDS1*SGTR 644Е-0в 100.0000%
Total POS1* вЛ«Е-0в
PDS10LMCLMF
4.62E-063.86E-05
10.7060%89^960%
Total PDS10 O1E-06
PDS11LMIISLMIL_
3.71E-024.00E-06
99.8923%0.1077%
Total PDS 11 3.71E-02
PDS12LMIISLMIL
6.90E-012.S1E-06
99.9990%0.0004%
Total PDS12 6Л0Е-01
RENEIT^CPSE THASE^B-7Шу" 1995~ ~Page~Sr3;3
SUMMARY REPORT
'i i
PDS21MSSODCCFELR__FSD__FWHF_HTPTLCLIVLCV__LEHCLESC1LESC2LFIC2LFIC3LMC__LMF__LMIISLMILLOCÄ1LOCA2
1Л6Е-066.38E-066.12E-061.36E-044.98E-0S2.72E-062.67E-042.89E-056.69E-054.S7E-063.98E-062ЛЗЕ-07Í43E-073.13E-072.61E-062Л4Е-041.62E-081.43E-021.06E-02
0.0039%0.0013%0.0013%0.0336%0.0012%0.0067%0.0637%0.0071%0.0166%0.0011%0.0010%0.0001%0.0001%0.0001%0.0006%0.0664%0.0000%3.6368%2.6027%
LOCAILRVSOLSBOCLSLICLSW__PCL__RPE__SRVSOSSLICTLF__TLOIATT
1.14E-031.2ЭЕ-069.89E-086.47E-073.S8E-016.06E-031.46E-062.96E-064.43E-066.76E-06U7E-021Л2Е-04
0.2834%0.0030%0.0000%0.0002%
88.6371%14978%0.0004%0.0007%0.0110%0.0014%3.1481%0.0476%
re joauer: ягяэдакдасаваиваЕ
0
Total POS2 4.04E-01
PDS 2*LOCAV 646E-07 14361%SGTR 3.76E-06 98.6640%
Total POST 341E-06
PDS3DCCF 1.39E-06 0.0869%ELR 2J8E-07 0.0014%FSD 1.54E-06 0.0960%FWHF 7.12E4I7 0.0044%HTPT 3.08E-06 0.0193%LCLIV 4.61E-06 0^816%LCV 8.06E-06. 0.0603%LEHC 1.87E-06 0.1167%LESC1 6.19E-07 0.0032%LFIC2 8.10E-08 0.0006%LOCAI 2Л7Е-03 14.1626%LOCA2 8.32E-05 0.6197%
— LOCAS -......... - ---------9.36E-07' - -------- - --------------0.0062%LOCAI 1.08E-06 0.0067%PCL 9.06E-04 6.6667%RPE 1.66E-07 0.0010%
----- SRVSO“'........ ~ ■6ЛЕ48 ~ 0.0004% —SSLIC 1.06E-06 0.0066%TLF - 2.76E-06 0.0172%TLOIÄ 1.26E-02 78.8661%TT 1.72E-06 0.1074%
Total PDS3 1.60E-02
.... ~ ------ -------- --- ' —........"- " РаеёХЗ?
SUMMARY RETORT
PDS3*
PDS4
SGTR 4.16E-0S 100X000%
Total POST 4.16E-08
1MSSO DCCF ELR_ FSD_ FWHF_ HTPT LCLIVLCV__LEHC LESC1 LFIC2
=.tHG3=«=.-= LOCA1 LOCA2 LOCA3 LOCAI LRVSO LSBOC LSLICPCL__RPE__SRVSO SSLICTLF__TLOIA
3.72E-04 6.96E-05 1.60E-06 1.03E-03 4.87E-0S 2.07E-04 3.05E-03 S.S6E-04 1.29E-03 3X8E-06 8.36Е-0в
^«XTE-Ofc — 1.46E-02 1.12E-02 1.64E-04 1.28E-03 6.29E-06 2.72E-08 1.71E-06 6.13E-03 1.10E-05 1.89E-05 1.17E-04 1.81E-04 1.26E-02 1.16E-03
0X868%0.1285%0X298%1X037%0X900%0X817%5X323%1X259%2X784%0X643%0X154%
--0X399%28X832%20J632%
0X026%2X563%0X976%0X050%0X315%
11X286%0X204%0X350%0X156%0X346%
23X384%2.1416%
Total PDS4 S.42E-02
POS4*LOCAVSGTR_
6.15E-071.60E-04
0X412%99X588%
PDS9
PDS9*
Total PIÄ4* 1.61E-04
LOCA1 1.59E-02 11X147%LOCA2 1.26E-02 9X613%LOCA3 1X6E-04 0X946%LOCAI 1.07E-03 0X010%LSW 9.74E-02 72X972%PCL__ 6.32E-03 4X313%
Total PDS8 1X3E-01
SGTR_ 347E-06 100X000%
3X7EJ
-RENEL - CPSE PHASER- July4-995. -Page-S—3r5-
■: ¡iУ ' j
-i‘i- Г.; r.4:-^rr- :r- • чТгН^-о .: t'y
SUMMARY КЕР(ЖТ
Table 3-2 Initiating Events Contributions ( all sequences included, with recovery)
POS1DCCF 4.82E-06 0.8232%ELR 7.22E-06 1.2319%FSD 1.77Е-0в 0.3020%FWHF З.ЭЗЕ-06 0.6883%HTPT 4.22E-07 0.0721%LCLIV 1.08E-05 1.8483%LCV 4.39E-06 0.7492%LEHC 1.02E-06 1.7388%LESC1 3.62E-08 0.8179%LESC2 4.64E-07 0.0776%LFIC2 3.99E-08 0.0088%LMC 3.5SE-Ó8 0.0081%IMF 2.96E-07 0.0606%LMIIS 3J8E-0e 0.6604%LMIL 1.73E-09 0.0003%' 1—------- - “^—30.0129%LOCA2 2.02E-05 3.4603%LOCA3 8.58E-07 0.1119%LOCAI 1.10E-06 0.1871%LSW_ 2.43E-04 41.4643%PCL 1.20E-06 2.0466%RPE 1.16E-06 0.1962%SRVSO 1.28E-08 0.0022%SSLIC 3.73E-08 0.8368%TLF 2.79E-07 0.0477%TLOIA 6.88E-06 11.7364%TT 8.54E-06 14664%
Total PDS1 5.86E-04
PDS1*SGTR_ 644E-06 100.0000%
Total PDS1* 644E-06
PDS10 ii ГГ
4.62E-06ЗЛ6Е-06
10.7060%89^960%
Total PDS10 441E-06
POSHLMIISLMIL.
3.71E-024.00E-06
99.8923%0.1077%
Total POSH 3.71E-02
PDS12LMIIS LMIL-----
5.90E-01 ' 2.61E-06
99.9996%0.0004%
Total PDS12 5.90E-01
PDS21MSSO 1.90E-08 0.4637%DCCF 6.38E-06 1.3096%ELR_ 6.12E-06 1.2461%FSD 2.12E-06 0.6163%FWHF 4.98E-06 1.2128%HTPT 1.33E-06 3^467%LCLIV 141E-06 34442%LCV 3.1 IE-06 0.7683%
RENEL - CPSE PHASE В- July 1995......... Rage-S—З76
•w
...: V .......
SUMMARY REPORT
LEHC 7JDE4S 1.7644%LESCT 4Л7Е4К 1.1129%LESC2 3JBE4B 0.9993%LFIC2 2ЛЗЕ47 0.0989%LFIC3 M3E-07 0.0892%LMC 3.13Е4Г 0.0762%LMF 2Л1Е4В 0.0369%LMIIS 846E4B 2.0699%LMIL 1Л2Е48 0.0037%LOCÄ1 1J5E4S 4.7640%LOCA2 2JBE« 6.3684%LOCA3 4.ПЕ46 10.2107%LOCAI 1.0SE45 2.6672%LRVSO 1J3E48 2.9867%LSBOC 9Л8Е4В 0.0241%LSLIC 647E47 0.1676%LSW 1.73E4» 42.1866%PCL 1.50Е«5 3.6579%RPE 1^Œ46 0.3633%SRVSO 2J96E4S 0.7219%
.т.идссу.''У ~ "■’ Trv.^.'r2r.T2_,i.. ...T’ --“=1.0079%TLF S.75E46 1.4008%TLOIA 141Е4Б 3.4278%TT 9J4E4B 2.2607%
Todi P0S2 4.11E-04
PDSrLOCAV 6A6E47 4^863%SGTR_ 1-22E4S 96.7137%
Todf POST 1.27E-0S
PDS3DCCF U9E4B 0.8320%ELR " 2JBE47 0.0136%FSD 1Л4Е46 04196%FWHF 7.12E47 0.0426%HTPT 3JBE«6 0.1844%LCLIV 1J8E46 0.1187%LCV 8Л8Б4В 04816%LEHC 1Л7Б46 1.1176%LESC1 6.18647 0.0310%LFÍC2 8.10608 0.0048%LOCAI 1.40643 83.6022%LOCA2 4Д8Б46 24393%LOCA3 8J6647 0.0600%LOCAI 148646 0.0643%PCL 743645 4.7408%RPE 146647 0.0099%SRVSO 641Б48 0.0040%SSLIC 146Б4В 0.0632%TLF 2J664B 0.1644%TLOIA 644646 4.0873%
. TT 172645 1.0289%
ТсЫ PDS3 1.67Е-03
RENEL-GPSEPHASE В-Julyl995 Page-S—-3-7-
SUMMARY REPORT
PDS3*SGTR_ 4.16Е-0в 100.0000%
Total PDS3* 4.16E-06
PDS41MSSO 4.09E-06 1.5956%DCCF 1.22E-06 0.0479%ELR 1.60E-0S 0.6268%FSD 9Л2Е-06 0.3838%FWHF 4Л7Е-06 1.9038%HTPT 642E-06 2.1170%LCLIV 2^7E-04 8^716%LCV 7.46E^)6 2Л59%LEHC 1.72E-04 6.7160%LESC1 3.48E-0S 1.3598%LFIC2 8.36E-06 0.3289%LFIC3 S.37E-06 0J099%LOCA1---------------- ' '• '6Л5Е-04 25.5808%LOCA2 6^2E-04 21.1785%LOCA3 S.19E-05 2.0282%LOCAI 1Л4Е-04 6.6224%LRVSO 6.29E-06 2.0662%LSBOC 2.72E-06 0.1(П5%LSLIC 1.71E-06 0.6671%PCL 1.11E-04 43542%RPE 1.10E-06 0.4317%SRVSO 1Л9Е-06 03397%SSLIC 1.17E-04 43606%TLF 2Л6Е-06 03986%TLOIA 1.08E-06 03216%TT 1.07E-04 4.1716%
Total POS4 2.S6E-03
POS4*LOCAV 6.15E-07SGTR_ 4.34E-05
1.1707%98Л283%
Total PDS4* 4J9E-05
LOCA1 1.50E-02 133402%LOCA2 1.26E-02 11.1446%LOCA3 136E-04 0.1114%LOCAI 1.07E-03 03435%LSW 8.36E-02 73.7526%PCL 9.15E-04 03077%
Total PDS9 1.13E-01
PDS9*SGTR_ 2.S1E-05 100Л000%
Total POST. Í61E-05.............................. ................
------------ RENEL - CPSE PHASE B—July 1995................ ............ ....... ........................................ Page S;- 3-8 -
SUMMARY RETORT
Table 3-3 PDS - I/Б and Seq. Contributions (only sequences with recovery)
PDS1
FSD_ FSD__3 2.10E-07 0.0688%
Total IE 2.10E-07 0.0688%
HTPT_ HTPT_4 4.20E-08 0.0138%
Total IE 4J0E-08 0.0138%
LCLIV LCLIV3 8.04E-07 0.2636%
Total IE 8.04E-07 0.2636%
Total IE 4Д2Е-08 0.0146%
LOCA1 LOCAIS 9.57E-05 31.3911%LOCA1 LOCA128 5.07E-05 16.6209%LOCA1 LOCA131 2.69E-06 0.8807%LOCA1 LOCAIS 9.34E-07 0.3064%
Total IE 1.50E-04 49.1992%
LOCA2 LOCA28 2.71 E-06 0.8879%
Total IE 2.71E-06 0.8879%
LSW LSW 2 5.21 E-05 17.0980%LSW__ LSW 19 1.80E-05 5.8861%LSW__ LSW 1 1.63E-05 5.3349%LSW LSW 21 6.50E-07 0.2131%LSW_ LSW 4 6.12E-07 0.2005%LSW_ LSW_20 1.1 IE-07 0.0365%
Total IE 8.77E-06 28.7692%
PCL PCL 6 1.87E-06 0.6120%PCL PCL 9 9.34E-07 0.3064%PCL__ PCL__19 1.84E-07 0.0604%
Total IE 2S9E-06 0.9789%
TLOIA TLOIA15 6.02E-05 19.7403%
Total IE 6.02E-06 19.7403%
TT___ TT___11 1.95E-07 0.0639%
Total IE 1.96E-07 0.0639%
Total PDS1 3.05E-04
1MSSO 1MSS016 3.12E-07 0.1675%
Total IE 3.12E-07 0.1676%
FSD FSD 11 1.88E-06 1.0084%FSD FSD 16 1.54E-07 0.0829%FSD FSD__6 8.91 E-08 0.0479%
Total IE 2.12E-06 1.1391%
"REMEL -XFSK PHASE В - JulyT^ PageSTT^
»*»
SUMMARY RETORT
HTPT_ HTPT_22 3.75E-07 0.2018%
Total IE 3.76E-07 0^018%
LCUV LCLIV42 Z28E-06 1.2269%LCUV LCLIV10 1.41E-06 0.7596%
Total IE 3.70E-06 1.9884%
LCV__ LCV__125 4.64E-07 0.2493%
Total IE 4.64E-07 0.2493%
LEHC_ LEHCJ04 1.08E-06 0.5785%
Total IE 1.08E-06 0.5786%
LMIIS LMIIS9 1.46E-06 0.7862%LMIIS LMIIS12 6.08E-07 0.3266%
Total IE 2.07E-06 1.1129%
LOCA1 LOCA112 3.35E-06 1.8004%LOCA1 LOCAI 41 2.69E-06 1.4480%LOCA1 LOCAIS 7.81 E-07 0.4194%ЮСА1 LOCAI 48 6.09E-07 0.3270%LOCA1 LOCA117 6.07E-07 0.3262%LOCA1 LOCA170 3.70E-08 0.0199%LOCA1 LOCAI 34 9.75E-09 0.0052%
Total IE 8.09E-06 4.3461%
LOCA2 LOCA217 1.34E-05 7.1781%LOCA2 LOCA252 1.25E-06 0.6734%LOCA2 LOCA240 3.31 E-07 0.1776%LOCA2 LOCA23S 2.75E-07 0.1476%
Total IE 1.62E-05 8.1788%
LOCA3 LOCA31S 4.84E-07 0.2598%
Total IE 4.84E-07 0.2698%
LOCAI LOCAI16 2.92E-06 1.5670%LOCAI LOCAI30 Z03E-07 0.1088%
Total IE 3.12E-06 1.6769%
LSW_ LSW 15 7.01 E-05 37.6496%LSW LSW 12 2.66E-05 ' 15.3742%LSW LSW 25 2.48E-05 13.3077%LSW LSW 27 5.37E-06 2.8877%LSW LSW 31 6.16E-07 0.3309%LSW_ LSW__29 5.48E-07 0.2945%
Total IE 1. ЗОЕ-04 69.8446%
PCL PCL 16 2.96E-06 1.5892%PCL_ PCL 23 6.11 E-07 0.3284%PCL__ PCL 33 5.12E-08 0.0275%PCL__ PCL__38 9.95E-09 0.0053%
Total IE 3.63E-06 1.9606%
SSUC SSUC34 4.59E-07 0.2468%
Total IE 4.59E-07" 0.2468%
CRENEL- - CPSE PHASE-B—J»riy 199-5 -------------------------- ------------------------—------- -Page S.-3-10
SUMMARY REPORT
TLOIA TLOIA17 1.16E-05 6.2406%
Total IE l.'KE-OS 6.2406%
TT TT 153 1.97E-06 1.0608%TT TT 168 1.19E-06 0.6415%TT TT 144 1.43E-07 0.0769%TT TT___29 8.23E-08 0.0442%
Total IE 3J9E-06 1.8236%
Total PDS2 1Л8Е4М
t-ч
>
с.
RENEL - GPSE PHASE S - July 1995- Page S. 3-11 —
I
j
Ii Í
/DANUBE/LV/MAX//N/CHNG/ «3
^ANyea^vmeHNQ/ jn/7131Q//SÇO//ODL/HE/
/6321Q//TCV/61 /N/FCOO/
/63210//TCV/62/N/FCOO/
/716ÔO//CONFIG/PG/ODP/HE/
///LOW/PROB-MAN/COMB//
/71BOO/ZV/ALL/N/EL/
/63210/ЯСу/б/М/РСОО/
/63210//TCY/8/N/FCOO/
/33120/PHT—PUMP-STOP///ODP/HE/
/63331//LCV/12/N/FCO/
/63331//LCV/11/N/FCO/
/Q/CTP///ODP/HE/
/43210//PMP/0fe/ODPR/HE/
/71610//PV/103/Q/FOOC/
ШЁВШШШб
Ш&.
/71690//PV/1001 /О/FCCO/ р^!
; //CLiv/////
///MED/PROB-MAN/COMB//
Figure 3.1 - Fussell-Vesely Importance for PDS1 ( only se ] with recovery)
1.
S£3
/71900/CH010/PP//N/BR/
/71900/CP003/PP//N/BR//71900/PMP/PP/|n/BR/
//RaW/NOV^NT////
/6321o//Tcv/e/N/(|coo/ yia-
/6321 o/zrcv/e/N/fjcoo/
/33120/PHT—PUMP-STOP///odp/HE/
/63331//LCV/11 /М/РСО/ /63331//LCV/12/WFeO/
/63210//TCV/61/N/fjCOO/
/63210//TC V/62/N/PCOO/
/OANUBE/LV/MAX//N/OHNO/
/71900//V/AL
///LOW/PROB-MAN/CPMB//
/7161Q//PV/103/Q/f^OOC/
/71680//PV/1001/Q/f ОСО/ ///MBB/RRQB^MAN/OpMB//
//cpv//////33310//UC V/11 j'N/EU
/3331Q//LCV/12/N/EL/
яттшша
“i1': ïl'..
)Шпш№ч«;н1ю«<шгвй»ма1 II
10 IS 20 25 30
Figure 3.2 - RAW Importance for PDS1 ( only seq with recovery)40 45 50
!
I
£
Figure 3.3 - RRW Importance for PDS1 ( only seq with recovery)
i!i
Figure 3.4 - Fusse! Vesely Importance for PDS2 (only seq. with recovery)
Figure 3.5 - RAW Importance for PDS2 (only seq. with recovery)¡i\
i
I .. г ■
/LLEV/DANUÖE///N//
/34320//V/1 Зб/TS/HE/
/52900//TK/5/ODM/HE/
/52900//TK/6/ODM/HE/
/7161Q//PV/1ОЗ/Q/FOOC/
/32110//TCV//ODL/HE/
/34610//V/45/OBUHE/
/COOL//HS/RCW/RDP/HE/
/43210//PMP/05/ODPR/HE/
/43220/Л//507/О0М/НЕ/
/34610//PV/7/T/FCC/ /43220//V/54S/Ol|)M/HE/
/43220/Л//51 7/rÓm/HE/
/33120/PHT-PUMP-STOP///OI )Р/НЕ/
/О/СТР/ЮрР/НЕ/
/43230//FCV/119/ОРМ/НЕ/
/71690//Р V/1001 /О/ FCCO/
//ÇLIV/////
//EPS-EWS/START//OÓS/HE/
Figure 3.6 - RRW Importance for PDS2 (only seq. with recovery)
i
Figure 3.7 Fussel Vesely Importance for PDS3 ( only seq? with recovery)
1 •J/33410//TCV//0DM/HE/1
/36110/MSSV/BLOKED//ODL/HE/ ,1!1 i
(//COOLDOWN/LEA K//ODP/Hp/ тттттжтмi
¿:í$:0:':ívy4 í:[.'s. ■ ■ >:::xo::/63331//LCV/11/N/FCÓ/ • Л,л«й4л ■- -Ч Ä- : :ч5”Ч-«,:ч'44««:ч< . ■ : í." =: .'Л
i1
/63331//LCV/12/N/FCO/ p-iï. <чч ч • 1 ' ’ ’ V 'ЛЧ' ’ ' ' "'ХХХ'У ГША'ХУШ^:<У:;ч 'УХКУШт'$PVX \”".у ч . iÍ •
//CLIV/////......................................... . 1 M *•*• ^ *í ! ' .'•I***!* Xi!v¡ ¡.'. ■!• • : • ■ / ' ' • .!■ y •, ^ ,
Í...........................................1 j......................................т.........................///MED/PROB-MAN/COMB//
i! * ■■ ■ ' 1 ■■ ■ 1 . Ч'.".'.. 1 1 .. .1///LOW/PROB-MAN/COMB//
i4 4 С 5V«sss г 4 Wsíwr*«. 4 4 Ч ÿÎV5s'*i^4-'<5,ÂVÿ>4y‘sï<Î's44'>«%ss,-;> ï •й^>'ТТ<ч ч-т*- > 4 - ч 5 - - V4 - 4"~ 5' 4i.................................. -1 ^ ......1----------- ----------------- 1 ■ =ц=----------- -----------—1
0 2 4 6 8 : 10 12
Figure 3.8 RAW Importance for PDS3 ( only seq. with recovery)
I! :
! Figure 3.9 RRW Importance for PDS3 (only seq. with recovery)
i
i
*
/34320//CV/76/T/IU
/34320//CV/77/T/IL/ /43230//FCV/1.10/Q/pOO/ /43230//FCV/110/Q/FCO/
/34320/HP/20/LOCA1 /RBP/НЕ/ . /43230//MV/1OOI/Q/FOO/
/34320//«^/10аЯ/вР/
/34320//RV/86/T/SP/
/34320//RV/85/T/SP/
/33410//TCV/12/Q/FCCO/ /33410//TCV/11/Q/FCCO/
/34320/Л//130/Т8/НЕ/ /34320/Л//134/TÇ/HE//34320/Л//135/TÇ/HE/
/03331//LGV/12/N/PCO/
/63331//LCV/11/N/FCO/
/34320//НХ/1 /N/LO/
//CLIV/////
ШИ
B
—__I________£:
........................................... ........... "чS3
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Figure 3.10 Fussel Vesely Importance for PDS4 (only seq. with recovery)
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/43230//PCV/11 в/Q/FÇO/1
/43230//PCV/118/Q/PCO/
/34320/HP/20/LOCA1 /R DP/H Е/
/43230//MV/1001/О/FÇO/
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/34320//RV/85/T/SP/
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/33410/ЯСУ/11/Q/FCÇO/
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1.08 1.1 1.12 1.14 1.16 1.18 1.2 1.22 1.24 1.26 1.28Figure 3.12 RRW Importance for PDS4 (only seq. with recovery)
< » iII
SUMMARY REPORT
4. INTERPRETATION OF RESULTS, CONCLUSIONS AND RECOMMENDATIONS
CPSE-Phase В resnits have bee obtained taking into account the designed documentation (up-dated at 01.01Л995), the Cemavoda Final Safety Report analyses and engineeringjudgement.
;
The conservative assumptions used in event sequences and systems analyses and also during accident sequences quantification process, are presented in the corresponding Sections of the Main Report and Appendices. Sane of these issumptions were as follows:
- Considering a 3 days mission time, some of mitigating possibilities had to be neglected (EWS finm Dousing Tank, secondary circuit as heat sink in case of loss of Service Water followed bp loss of class IV power); more systems had to be inseried to assure the required function (EWS from Dousing Tank and in pumped mode, secondary circuit supply from Demineralized Water Plants
- Mission toe for voy amH LOCA was conadered to be 3 months instead of 2 weeks;
- Class IV power supply itcovery within 30 min. has been neglected;
- In case of very small LOCA followed by loss of Class IV, the D2O recovery system contribution was neglected;
- The automatic action to configurate Back-up Cooling system (selection of numbers of chillers) was neglected, as the technical solution has not been established yet;
-The success criteria for Moderator and SDCS were considered to be the same during whole mission times
-The components unisoUfe (considering the available information) were considered unrepaired;
- Refering to I/E events frequency, a great value for Primary Coolant Leaks (0.1/y) was considered; also, refering to Loss <£f Service Water VE frequency estimated in CPSE-Phase B, some very conservAve assumptions had been considered:
.- a Danube low leed greater than the design low level, when RSW pumps trip if theanterotoric medhanism is not actuated;
- drain pumps frutares leads directelly to loss of RSW pumps;,
- RSW pipes verdis necessary in case of RSW pumps restarting after loss of Class IV power and Class in establish;
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SUMMARY REPORT
- As Cernavoda APOPs were still not available, the emergency procedures for similar Candu NPP were consulted;
- The recovery factors were considered as recommended in " Procedures for Conducting Probabilistic Safety Assessments of Nuclear Power Plants-Level 1"- Safety Series No. 50- P-4, the same factor being used for all the operator actions within more than 60 minutes.
The final results on accident sequences, leading to critical PDSs shown that, on long term, the plant operation (during accident conditions) is principlely sensitive to human error probabilities and system component reliability parameters such as event occurrence frequencies, test intervals and component repair times.During some accidents the operator should configurate the system or to start a stand-by equipment in short time (such as : back-up cooling system, stand-by D20 feed pump, auxiliary condensate system pump, back-up cooling to main feedwater system, initiation of ECCS on case of very small LOCA, control of fail opened valves to SDCS & moderator heat exchangers after loss of instrument air or dual computer failure followed by consequential loss of class IV).The future (living) PSA analyses have to concentrate on risk monitoring to optimize certain reliability parameters and to reveal how the operation personnel have to be trained to manage the accident and a part of these activities should become automatically initiated.The continuance of the PSA studies could have many benefits related to Cernavoda NPP operation in different conditions.This study considered only the plant state when the initiating events originate from (full power) but the actual situation is that in PSA analyses have to include initiating events that could originate during different plant states (e.g. plant shutdown).
RENEL - CPSE PHASE В - July 1995 PageS. 4-2
SUMMARY REPORT
5. OVERVIEW OF PROCEDURES AND METHODS
The entire performance activity of the CPSE - Phase В Study involved a number of 10 major procedural steps, as described in RENEL-GEN document MG-01/07-EPSN-000, Rev.2. These steps are as follows:
- project co-ordination;
- initiating events selection;
- plant damage states definition;
- event trees analysis;
- fault trees analysis;
- human errors modelling;
- accident sequence quantification;
- implementation, validation and running of computer codes;
- uncertainty analysis;
- preparation of documentation.
The general flow of work/information among these steps is shown in Figure 5-1. It is important to recognize that this flow is not always linear and that there are many iterative loops among the various steps. In turn the procedural steps are divided into tasks, as described below, which form the framework of the CPSE - Phase В procedures.
5.1 Project co-ordination
This procedural step included the actions and activities necessary for the organization and management of the study: definition of the objectives, the scope and the project management scheme of the study, the selection of the methods and establishment of procedures, the selection of personnel and the organization of the teams that perform the study, the training of the teams, the preparation of project schedule, the estimation and securing of the necessary funds and the establishment of quality assurance manual and procedures.
All these actions and activities have been clearly stated and defined in the QA manual and its specific procedures and instructions have already been finalized. „The_foUowing remarks. haye to_ be mentioned:
- the CPSE - Phase В Study has been performed by CPSE group, including the coordination group (GCS), the internal review group (GRI) and the working group, the last one composed of two separate teams (CITON Bucuresti-Magurele and ICN- Pitesti), with clearly stated specific responsabilities (see document MG-01/07-EPSN- 000, Rev.2);
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SUMMARY RETORT
- the personnel involved in the performance of CPSE - Phase В Study has been selected, trained and autkrized according to procedural requirements (see procedure PP-01/07-EPSN-006, Re*I);
- the training of the CPS group members covered areas such as PSA techniques and plant systems and operaâmal procedures. The following types of training have been attended: PSA workshop (held in Romania by IAEA experts during 1987-1992); individual PSA feQowsbfs under ROM/9/008 Technical Cooperation Project and courses on plant systems and operational procedures (held in Romania, at Cernavoda NPP site during 1991);
- the resources allocated so complete the CPSE - Phase В Study represent 80 man- years, for a four years peœd, starting since 1992.
- the entire performarfe process of CPSE - Phase В Study conforms to the requirements of the QA pogrom, clearly stated and defined in the EPSN QA manual (MG-01/07-EPSN-000, lev.2) and its associated 32 procedures and instructions elaborated and issued.
5.2 Initiating events selotion
The second procedural step <Ык with the identification of the initiating events (accident initiators) that can challenge the safety functions incorporated in the Cernavoda NPP design, the selection of the method ned for initiating event frequency quantification and the quantification of initialmg eventsiientified.
Related to this step, fie Mowngremarks have to be done, which are particular to the CPSE - Phase В Study:
- the general appoach used for the selection of the initiating events under consideration is toed on reference to existing lists: Darlington Probabilistic Safety EvahiatkmpPSE) Study and Kema Study (CANDU600 Study);
- the initiating cent frequencies are mainly based on actual operating foreign expenence for CSNDU reactors (Le.DPSE Study and Kema Study) and on fruit tree analyses&r Cernavoda NPP (see Appendix В of the Main Report).
For CPSE - Phase B, a list of 34 initiating events resulted, grouped into three categories, according to their effect on the plant (see Section 3.2 and Appendix A, Section A.3 of the Main Report)::
- transients (21 everts);- loss of coolant accidertsfrom PHTS (7 events);- loss of moderator and ad shield cooling (6 events); -
Where possible, calculated inCmting events frequencies were compared against actual experience for CANDU reactora.The frequencies were found to be comparable.
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г» я* HÄK-Steju
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5.3 Plant damage states definition
This step dealt with the definition of different core damage categories and successful end states to be used in CPSE - Phase В Study:
- the establishment of the criteria to be used in assessing the consequences on the fuel integrity;
- the establishment of the bases for defining the different consequence categories;- the definition of fuel damage categories.
The performance of the above procedural step in CPSE - Phase В resulted in the definition of 13 plant damage states (PDSO to PDS 12) and 5 successful plant end states (designed by OK) (see Appendix A, Sect.A4.1.2 of the Main Report). In defining the different PDSs, the following criteria have been taken into account:
- each PDS represents a collection of event sequences judged to have similar characteristics with respect to accident progression;
- the characteristics associated to event sequences allocated to a given PDS refer to:
(a) degree of fuel damage, and(b) conditions of PHTS and reactor core cooling
Taking into account the radioactive sources considered in CPSE-Phase В (see section 1.2), the event sequences developed are grouped in the following 9 PDS:
PDSO - Early core disassembly;
PDS 1, PDS2 - Late core disassembly (with high/low PHTS pressure);
PDS3, PDS4 - Loss of core cooling requiring the moderator its a heat sink;
PDS9 - Loss of PHTS integrity/Small LOCA with successful initiation ofECCS;
PDS10, 11, 12 - Release of Moderator into containment.
The 5 successful end states in CPSE - Phase В Study incorporates the various states of PHTS cooldown with the HTS pumps, thermosyphoning of SDCS.
(a) forced flow and full inventory;(b) thermosyphoning flow with full inventory,(c) thermosyphoning flow with partial inventoiy; _ _(d) SD'CS operating in “HTS pump mode”(e) SDCS operating in “SDC pump mode”
5.4 Event tree analysis
This procedural step in the performance process of CPSE - Phase В Study dealt with the construction of event trees for all initiating events (34) selected in the second step. As the
■RENEIr^CPSE PHASRB ^ July 1995“^“ ~ ~ " _ " ' ~ Г"~”ГТ~.~“7РЙ8Ь'8Г5::Г—.Z
SUMMARY RETORT
dependences between front line systems and support systems do not appear in the event trees developed, these event trees are of small dimensions (“small event trees - large fault trees” approach). There are only two exceptions concerning this approach: electric power supply system and back-up cooling system. Also, as the event trees display as headings safety functions and systems status, the event trees are of functional/systemic type.
The major tasks forming this procedural step are:
- identification of functions/systems to be performed/called following the initiating event occurrence;
- construction of the event tree for the initiating event selected;- allocation of the appropriate PDS to each event sequence generated in the event tree.
The results of this step in the performance process of CPSE - Phase В are presented in App.A of the Main Report.
S.S Fault tree analysis
This step included all the activities of system failure modelling in terms of basic component unavailabilities and human errors, using the fault tree analysis method. The following major tasks can be distinguished for this step:
- fault tree logic development for the involved system, for all top events applicable defined in the previous step;
- fault tree labelling;
- fault tree quantification.
For CPSE - Phase В Study, a number of 33 fault trees analyses were performed for 32 plant systems, including front line systems, support systems and support support systems. The corresponding reports are presented in Appendix B, Sections В. 1 to B.33 of the Main Report.
5.6 Human errors modelling
The objective of this procedural step was the modelling and quantification of potential contribution of human errors to the frequency of core damage and frequency of different plant damage states. This involved both the selection of the human reliability analysis method as well
- * as the-identification of the-opportunity-for error and-the-estimation of the probability ofoccurrence.
For CPSE - Phase В Study, the following remarks have to be done:
- the human reliability analysis method selected and used is Swain method;
- the event trees developed do not include recovery human errors;
SUMMARY RETORT
- the recovery human actions are taken into account in the integration process;
- omission human errors are considered in all fault trees developed.
For more details on human errors modelling see Sections 4.3 and 5.3. of the Main Report.
5.7 Accident sequence quantification
This procedural step includes all the tasks associated with the integration of Fault Trees/Event Trees and the quantification of the accident sequences. The plant model built during the previous steps (event trees and fault trees analyses) is quantified using the necessary parameters available (i.e. frequencies of initiating events, component unavailabilities and human error probabilities). The tasks to be performed inciude the determination of the accident sequences to be quantified, the manipulation of the accident sequences into a form suitable for quantification) and the actual quantification of the sequences using point values. The relative importance of various contributors to the core meh frequency and different plant damage states frequencies are also determined.
The detailed description of the integration process for CPSE - Phase В Study, including the inputs, methods, products and the computer codes used in the analysis, is presented in Section 6 - Accident sequence quantification of the Main Report.
5.8 Implementation, validation and running of computer codes
The main objective of this procedural step is the development of a computer code package for (see MG-01/07-EPSN-000, Rev.2):
- qualitative and quantitative analysis and graphical representation of fruit trees;
- integration of fault trees/event trees;
- input data processing for qualitative and quantitative analysis of fault trees;
- files interface of computer codes used;
- codes validation and CPSE working algorithm.
Fault tree processing and editing were performed using EDFT computer program and event trees were'pPbdä^'u^'^ETTTfieliwö c¡^''áñépáñT)nm‘m^iited'TSAloffmi- package, PSAMAN, which provides the overall control of the PSA project elements. This PSA software package, written in Visual Basic under Windows, has been developed at ICN-Pitesti during last months, in order to cover the computing requirements of the CPSE project. The basic algorithms implemented in PSAMAN are similar with those useb in PSAB, the older code used for CPSE Phase A A limited validation of PSAB was made during IAEA IPERS mission for CPSE Phase A (October 1990) and during a scientific visit in Vienna by comparison with PSAPACK. PSAMAN has been presented to regulatory body and an extended validation plan was agreed, according to CNCAN requirements. Comparisons
RENEL - CPSE PHASE В - July 1995 - -..........- _ -.... .............. .... .... .......................... ‘ - Page S. 5-5
performed against the available computer codes (ERRAS 4) gave identical results for fault tree evaluations (both quantitative and qualitative), in equivalent computing times.
The detailed information concerning the computer code package used in CPSE - Phase В Study are provided in Section 6.6 of the Main Report.
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SUMMARY RETORT
5.9 Uncertainty analysis
The objective of this step was to provide the quantitative measures of the uncertainties in the results of the CPSE - Phase В Study, namely the frequency of core damage and frequency of different plant damage states.
~ ~ ^t ^e moment, therë'is not yet äh uncertainty analysis performed for CPSE - Phase B. This will become available at a later stage.
5.10 Preparation of documentation
The last procedural step included all the aspects of documentation of the CPSE - Phase В Study. In accordance with IAEA recommendations, the CPSE - Phase В documentation is divided into three major parts:
- summary report;
- mam report;
- appendices to the main report
The details on the external documentation prepared for CPSE-Phase В are presented in Section 6 of the Summary Report.
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SUMMARY REPORT
6. ORGANIZATION OF CPSE - PHASE В EXTERNAL DOCUMENTATION
As recommended (Safety Series No. 50-P-4 - Procedures for conducting Probabilistic Safety Assessments of Nuclear Power Plants - Level 1, Vienna 1992) the external documentation of CPSE - Phase В Study is divided into three major parts:
- Summary Report;
' -Main Réport;
- Appendices to the Main Report
The purpose of the Summary Report is to provide an overview of the PSA project’s motivations, assumptions, objectives, scope, results and conclusions at a level which is useful to a wide audience of reactor safety specialists and which is adequate for high level review.
The Summary Report is designed to:
- support high level review of the PSA;
- communicate key aspects of the study to a wider audience of interested parties;
- provide a clear framework and guide for the reader or user prior to consulting the Main Report.
The contents of Summary Report is as following:
1. Introduction
2. Results of the analysis
3. Results of importance and sensitivity analyses
4. Interpretation of results, conclurions and recommendations
5. Overview of procedures and methods
6. Organization of CPSE - Phase В external documeñtation
The purpose of the Main Report is to give a clear and traceable presentation of the complete CPSE - Phase В Study, including plant descriptfon, study objectives, methods used initiating events considered, plant modelling results and conclusions.
The'Main Report, together with its appendices is designed: ' " ------ -----------
• to support technical review of the CPSE Phase В Study;• to communicate key detailed information to interested users;• to permit the efficient and various application of the CPSE - Phase В models and
results;• to facilitate the updating of modds, data and results to support a continuing safety
management programme.
- Page Sr 6-1RENEL - CPSE PHASE В - July 1995
SUMMARY REPORT
The CPSE - Phase В Study Main Report в organized ra 7 sections, which follow the logical path leading to the final results:
(a) overview of the study and plant and site desaipthm (Sections 1 and 2); ф) identification of radioactive sources, accident ini&tors and plant response (Section 3);(c) accident sequence modelling (Section 4);(d) data assessment and parameter estimation (Sectim 5);(e) accident sequence quantification (Section 6);(f) display and interpretation of results (Section 7).
The Main Report contents is as follows:
1. OVERVIEW OF THE STUDY
1.1 Background and objectives of the study1.2 Scope of the study1.3 Project organization and management1.4 Project implementation1.5 Overview of procedures and methods1.6 Report organization
2. PLANT AND SITE DESCRIPTION
2.1 General plant characteristics2.2 Plant systems2.3 Plant site
3. IDENTIFICATION OF RADIOACTIVE SOURCES, ACCIDENTINITIATORS AND PLANT RESPONSE
3.1 Sources and conditions of radioactive releases3.2 Selection of initiating events3.3 Plant functions and systems relations3.4 Plant system requirements3.5 Grouping of initiating events
4. ACCIDENT SEQUENCE MODELLING
4.1 Event sequence modelling4.2 System modelling4.3 Human performance analysis4.4 .. -Qualitative dependence analysis-------------- ------------------ ----------4.5 Impact of physical processes in the progression cf accident sequences4.6 Classification of accident sequences into plant damage states
5. DATA ASSESSMENT AND PARAMETER ISTIMATION
5.1 Initiating event data and frequencies5.2 Component data and parameters5.3 Human performance data and parameters
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SUMMARY RETORT
6. ACCIDENT SEQUENCE QUANTIFICATION
6.1 General concept of the quantification process6.2 Analysis of system models6.3 Accident sequence quantification6.4 Importance and sensitivity analysis6. S Description of computer codes used in the analysis
7. DISPLAY AND INTERPRETATION OF RESULTS
7.1 Dominant sequences contributing to core damage frequency7.2 Results of uncertainty analysis7.3 Results of importance and sensitivity analysis7.4 Interpretation of results, engineering insights7.5 Credibility and qualification of results7.6 Conclusions, recommendations and potential applications
The three sets of Appendices to the Main Report contain the material whose bulk and level of detail are such that its inclusion in the Main Report is unwarranted.
Appendix Ajs acctually an event tree report, organized in 6 sections, including the specific information for the event tree analysis phase of the CPSE Study: initiating events selection and grouping , plant damage states definition, event tree description and presentation and event tree headings definition. A list of the reference documents used is also provided.
Appendix В presents the results of the system analyses performed to support the development and quantification of accident sequences. The information provided includes detailed descriptions of plant systems, fault tree models and data needed for their quantification. This appendix consists of 33 separate modules (sections), each dedicated to individual systems included in the analysis (Bl + B33).
Appendix C contains the reliability data used for fault trees quantification (initiating events frequency and top events unavailability estimation).
The detailed contents of these three sets of the CPSE-Phase В Main Report Appendices is as follows:
A. EVENT TREE REPORT
A. 1 IntroductionA.2 Reference documentsA3 Initiating eventsA4 Event tree analysisA. 5 Event tree drawings and generated sequencesA. 6 Event tree headings description
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SUMMARY RETORT
В. SYSTEM ANALYSIS
B.l Shutdown system No. 1 F/TB.2 Shutdown system No.2 F/TВ. 3 Emergency Core Cooling System F/TB.4 Reactor Regulating System F/TB.5 Primary Heat Transport Pumps F/TВ. 6 Shutdown Cooling System FATB.7 Pressure and Inventory Control System F/TВ. 8 Overpressure Protection System F/TB.9 D2O Supply System F/TВ. 10 Moderator Cooling System F/TB. 11 End Shield Cooling^System F/TВ. 12 Steam Generators íevel Control System F/fB.13 Feedwater System F/TB.14 Condensate Storage System F/TВ. 15 Emergency Demineralized Water System F/TВ. 16 Demineralized Water Plant FATВ. 17 Fire Protection System F/TВ. 18 Main Steam System F/TВ. 19 Turbine By-Pass System F/TB.20 Air Extraction System F/TB.21 Governor Oil System (Hydraulic Fluid) F/TB.22 Circulating Water Supply (Condenser Cooling System) F/TB.23 Turbine Steam System F/TB.24 Emergency Water Supply System F/TB.25 Class IV Electrical Power Supply System F/TB.26 Class IB Electrical Power Supply System F/TB.27 Emergency Power Supply System F/TB.28 Raw Service Water System F/TB.29 Recirculated Cooling Water System F/TB.30 Instrument Air System F/TB.31 Chilled Water System F/TB.32 RSW Back-up Cooling Water System F/TB.33 Main Condensate Extraction System F/T
C. RELIABILITY DATA
In order to guide the reader to the parts of the documentation that deal with specific items, a “road map” relating sections of the Summary Report to sections of the Main Report and the Appendices is included in Table 6-1........
D. CALLINGS TREE
This appendix contains logical connections between different modules (event tree headings, high level fault trees and fault trees).
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SUMMARY RETORT
Table 6-1 Relation between Summary Report and Main Report sections
Summary Report Section Corresponding Main Report Section(s)
Comments
S. 1 Initiating Events Selection
3.2 Selection of Initiating Events 3.5 Grouping of Initiating Events
Section A.3 of Appendix A to Main Report contains the complete list of initiating events (A.3.1) and the 6 groups of initiating events considered in the analysis (A.3.2)
5.2 Plant Damage States (PDS) definition
3.1.3 The definition of core damage states4.6 Classification of accident sequences into plant damage states
Section A14.1.2 of App.A to Main Report contains definition of all 13 PDS used inPSA studies
5.3 Event Tree Analysis 3.3 Plant functions and systemrelations...... ............ —.....
4.1 Event sequence modelling
3.4 Plant system requirements
Section A.4.1.1 of App.A to Main Reportcontains the descriptionjof the safety -------functions required in case of accident. The analysis assumptions used in plant response evaluation are presented in Section A.4.1.3
Section A.4.2 to A.4.7 of App.A to Main Report contains the detailed presentation of the 6 groups of Initiating Events analysed in CPSE - Phase B, as follows:
1. LOCA Section A.4.22. Failures in Moderator & Section A.4.3End Shield Cooling Systems3. Failures in Secondary Section A.4.4Circuit (others than breaks)4. Reactor forced shutdown Section A.4.5 and failures in PHTS (otherthan breaks)5. Failures in plant support Section A.4.6 systems6. Breaks in secondary circuit Section A-4.7
Section A.5 of App.A to Main Report contains the event tree drawings (for the 34 Initiating Events analysed)
Section A.6 of App.A to Main Report contains the definition of headings (high level included) used in the event sequences
5.4 Fault Tree Analysis 4.2 System modelling Section 4.2 of Main Report contains details about plant systems modelling.Sections B.l to B.33 contain the reports of the fault tree developed for 32 systems.
5:5 Humanerrors ..........modelling
<t.j гшпшП ршиппапсс analysis ' oecuon 4:Z oi мзш Report contains* *.........information about human reliability.Sections В. 1 to B.33 contain the assumptions used for human errors modelling in fault trees.
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SUMMARY REPORT
Summary Report Section Corresponding Main Report Section(s)
Comments
S.6 Accident sequence quantification
5.1 Initiating event data and frequencies5.2 Component data and parameters
The reliability data used in CPSE - Phase В are contained in App.C to Main Report.
6.2 Analysis of system models Top events probability is contained inApp.B.l to B.33 to Main Report
2. Results of the analysis 6.3 Quantification of accident sequences
3. Results of importance and sensitivity analyses
6.5 Importance and sensitivity analysis
5.7 Implementation, validation and running of computer codes
6.6 Computer codes used in the analysis ..................
Appendix 6.5 of Main Report contains detailed information on computer «odes- ' -n (EDET, EDFT) used in CPSE - Phase B.
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