2010/07/14 Areva EPR DC - DRAFT Response to U.S. EPR ... · ACI SP 152-3 state.” ACI SP 15 the...

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ArevaEPRDCPEm Resource

From: BRYAN Martin (EXTERNAL AREVA) [[email protected]]Sent: Wednesday, July 14, 2010 11:21 AMTo: Tesfaye, GetachewCc: DELANO Karen (AREVA); ROMINE Judy (AREVA); BENNETT Kathy (AREVA); SLAY Lysa

(AREVA); RYAN Tom (AREVA); COLEMAN Sue (AREVA); PATTON Jeff (AREVA); CORNELL Veronica (EXTERNAL AREVA); VAN NOY Mark (EXTERNAL AREVA); Miernicki, Michael

Subject: DRAFT Response to U.S. EPR Design Certification Application RAI No. 376, FSAR Ch. 3, Question 03.08.05-30

Attachments: RAI 376 Question 030805-30 - DRAFT.pdf

Getachew, On July 13, AREVA NP provided a revised schedule for RAI 376-03.08.05-30 (August 16, 2010) to allow time to interact with the NRC on the draft response. The draft response to this question is attached. Let me know if the staff has questions or if the response can be sent as final. Thanks, Martin (Marty) C. Bryan U.S. EPR Design Certification Licensing Manager AREVA NP Inc. Tel: (434) 832-3016 702 561-3528 cell [email protected]

Hearing Identifier: AREVA_EPR_DC_RAIs Email Number: 1690 Mail Envelope Properties (BC417D9255991046A37DD56CF597DB7106DCF4FB) Subject: DRAFT Response to U.S. EPR Design Certification Application RAI No. 376, FSAR Ch. 3, Question 03.08.05-30 Sent Date: 7/14/2010 11:21:18 AM Received Date: 7/14/2010 11:21:38 AM From: BRYAN Martin (EXTERNAL AREVA) Created By: [email protected] Recipients: "DELANO Karen (AREVA)" <[email protected]> Tracking Status: None "ROMINE Judy (AREVA)" <[email protected]> Tracking Status: None "BENNETT Kathy (AREVA)" <[email protected]> Tracking Status: None "SLAY Lysa (AREVA)" <[email protected]> Tracking Status: None "RYAN Tom (AREVA)" <[email protected]> Tracking Status: None "COLEMAN Sue (AREVA)" <[email protected]> Tracking Status: None "PATTON Jeff (AREVA)" <[email protected]> Tracking Status: None "CORNELL Veronica (EXTERNAL AREVA)" <[email protected]> Tracking Status: None "VAN NOY Mark (EXTERNAL AREVA)" <[email protected]> Tracking Status: None "Miernicki, Michael" <[email protected]> Tracking Status: None "Tesfaye, Getachew" <[email protected]> Tracking Status: None Post Office: AUSLYNCMX02.adom.ad.corp Files Size Date & Time MESSAGE 518 7/14/2010 11:21:38 AM RAI 376 Question 030805-30 - DRAFT.pdf 1545757 Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date: Recipients Received:

Response to

Request for Additional Information No. 376, Question 03.08.05-30 - DRAFT

3/25/2010

U. S. EPR Standard Design Certification AREVA NP Inc.

Docket No. 52-020 SRP Section: 03.08.01 - Concrete Containment

SRP Section: 03.08.03 - Concrete and Steel Internal Structures of Steel or Concrete Containments

SRP Section: 03.08.05 - Foundations Application Section: 3.8

QUESTIONS for Structural Engineering Branch 2 (ESBWR/ABWR Projects) (SEB2)

DRAFT

al Sal Snts nts

oundations oundationion: 3.8 ion:

Branch 2 (ESBWR/Aanch 2 (ES

AREVA NP Inc.

Response to Request for Additional Information No. 376, Question 03.08.05-30 - DRAFT U.S. EPR Design Certification Application Page 2 of 6

Question 03.08.05-30:

Follow-up to RAI 155, Question 03.08.05-11

The response to this RAI indicates that the criterion for differential settlements of 0.5 inches per 50 feet in any direction across the NI foundation basemat is obtained from a geotechnical report prepared for U.S. EPR Design Certification. In addition, it refers to a study in which structural analyses were performed with and without initial tilt settlements for the softest soil type considered. The results of this study show negligible differences in both soil bearing pressures and stresses in the basemat. The staff finds that the RAI response requires further clarification as discussed below. This clarification is needed to determine if the foundation design related to differential settlement meets the acceptance criteria in SRP 3.8.5.II.

1. The RAI response did not provide a detailed explanation as to how the differential settlement criterion was determined. As requested in the original RAI, provide the technical basis for determining this differential settlement criterion.

2. The RAI response did not provide a detailed explanation on how the effects of the differential settlements are considered in the design of the NI basemat (i.e., details of the FE model used, how the prescribed displacements are imposed on the model, and how these prescribed displacements were considered in the load combinations). Therefore, the staff requests that this information be provided, as requested in the original RAI.

3. Since the RAI response uses the terms “tilt settlement” and “inclination”, it appears that a rigid body-type evaluation was performed. The staff finds this approach unacceptable. For a typical shear wall structure, a differential settlement of 0.5 inches per 50 feet can result in significant demands on the structure when the differential settlement is defined as a vertical shear deformation imposed on the basemat, and not as a rigid body rotation. The demands on the structure will be a function of the stiffness of the foundation soils supporting the basemat. If such demands are ignored in the design of the basemat, then overstressed conditions and cracking of the basemat could result. Therefore, clarify the approach used to determine the effects of differential settlements.

Response to Question 03.08.05-30:

1. The U.S. EPR standard plant considers angular displacement (tilt) and flexural displacement. The angular displacement (tilt) value of 0.5 inches per 50 feet of length of Nuclear Island (NI) Basemat is considered for equipment performance criteria. The effects of tilt settlement were investigated by rotating the ANSYS model of the NI about the East-West axis. The increase in soil bearing pressure and stresses within the NI Common Basemat were negligible. The flexural settlement value of 0.5 inches in 50 feet is a maximum basemat demand established through analysis and design. The analysis component of the flexural settlement criterion is based on the soil penetration contours for the U.S. EPR finite element model (FEM) using the elastic soil springs, when subjected to 100 percent dead load, 25 percent live load, and 75 percent precipitation load shown in U.S. EPR FSAR Tier 2, Figures 3.8-106 through 3.8-115. This condition results in a maximum value of approximately 0.25 inches in 50 feet flexure of the basemat. An additional 0.25 inches in 50 feet is considered through design (see Part 2 of this response) to account for other items such as long-term settlement, construction sequence, and lateral soil variability.

DRAFT

to howto horovide the trovid

anation on how the effecanation on how the ebasemat (i.e., details obasemat (i.e., details o

on the model, and hown the modelombinations). Thereforetions).

he original RAI. he original RAI.

erms “tilt settlement” anlt settlement” aned. The staff findsed. The staff finds this a

al settlement of 0.5 inchal settlement of 0.5en the differential settleen the differential sett

e basemat, and not as asemat, and not as on of the stiffness of theon of the stiffn

in the design of the basin the design of theuld result. Therefore, clauld result. Therefore, clents. ents.

03.08.05-03.08.05-

AREVA NP Inc.


U.S. EPR FSAR Tier 2, Section 3.8.5.5.1 will be revised to define that the standard plant has been designed for the flexural displacement associated with soil spring stiffness of the U.S. EPR and an imposed 0.25 inches per 50 feet (see Part 2 of this response) of other flexural displacement. U.S. EPR FSAR Tier 2, Section 3.8.5.5.1 will be revised to describe that the investigation of the effects of an angular displacement (tilt) of 0.5 inches in 50 feet and the results were found to be negligible for soil bearing pressure.

2. In addition to forces and moments due to the elastic soil springs, the NI Common Basemat Structure foundation basemat for the U.S. EPR plant considers other settlement effects (e.g., consolidation, construction sequence, lateral soil variability) by assuming a flexural settlement of 0.25 inches in 50 feet. The effects of other flexural settlement of the NI foundation basemat are investigated through manual calculations by representing the basemat as one foot wide fixed-fixed Bernoulli beams displaced at one support as shown in Figure 03.08.05-30-1. The total differential displacement at the support of each strip is obtained by linearly extrapolating 0.25 inches per 50 feet for the entire length of the strip. Figure 03.08.05-30-2 shows the basemat strips and calculated moment and shear locations. Table 03.08.05-30-1 and Table 03.08.05-30-2 show the moment and shear results. The resulting values of moment and shear are calculated using an effective concrete modulus of elasticity adjusted for creep relaxation in accordance with ACI SP 152-3, “Mat Foundation Design – A Soil-Structure Interaction Problem.” ACI SP 152-3 states that as the displacement remains constant over time, the values of moment and shear reduce with time until they reach a residual value. In addition, ACI SP 152-3 applies the methodology of creep relaxation during construction and over the life of the structure. The maximum values for moment and shear are applied over the entire length of the strip. These moment and shear values are manually included with the results of the ANSYS model to provide a design that accounts for flexure and shear associated with the soil spring analysis and flexure and shear associated with other settlements. The moments and shears due to other settlement are considered with each load combination as a live load (i.e., the load factor used corresponds to the live load factor).

The U.S. EPR FSAR Tier 2 will be revised to clarify the COL Item 2.5-7 in Table 1.8-2 and Section 2.5.4.10.2. U.S. EPR FSAR Tier 2, Section 3.8.5.5.1 will be revised to describe the U.S. EPR settlement criterion.

AREVA NP will address the effects of NI Basemat settlement pertaining to the superstructure in the Response to RAI 354, Question 03.08.05-22.

3. The approach used to capture the effects of differential settlement on the basemat is addressed in Part 2 of this RAI response.

FSAR Impact:

U.S. EPR FSAR Tier 2, Table 1.8-2, Section 2.5.4.10.2, and Section 3.8.5.5.1 will be revised as described in the response and indicated on the enclosed markup.

DRAFT

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ted using an effective coted using an effectdance with ACI SP 152-dance with ACI SP 152

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dition, ACI SP 152-3 apdition, ACI SP 15and over the life of the sd over the life of th

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SAR Tier 2 will be reviseSAR Tier 2 will be re0.2. U.S. EPR FSAR T0.2. U.S. EPR FSAR Tment criterion. ment criterion.

ess the efess the efespoespo

AREVA NP Inc.


Table 03.08.05-30-1—Moments and Shears for E-W Strips by Region

Building Basemat Thickness (ft) Strip Length (ft) M (k-ft/ft) V (k/ft)

FB 9.84 156.5 ±290.8 ±3.7

SB1/SB4 (Outer) 13.12 89.7 ±988.9 ±18.2

SB1/SB4 (Inner) 9.84 89.7 ±646.0 ±18.2

SB23 (Inner) 9.84 177.5 ±256.5 ±2.9

SB23 (Outer) 13.12 177.5 ±607.8 ±6.8

RCB 10.83 178.2 ±340.1 ±3.8

Table 03.08.05-30-2—Moments and Shears for N-S Strips by Region

Building Basemat Thickness (ft) Strip Length (ft) M (k-ft/ft) V (k/ft)

FB 9.84 71.4 ±637.7 ±17.9

FB 14.44 78.7 ±1093.1 ±23.7

SB1/SB4 (Outer) 13.12 99.1 ±1088.9 ±22.0

SB1/SB4 (Inner) 9.84 99.1 ±459.5 ±9.3

SB23 (Outer) 13.12 90.1 ±988.1 ±18.1

SB23 (Inner) 9.84 90.1 ±641.9 ±18.1

RCB 10.83 178.2 ±340.1 ±3.8

DRDDDRRRARAARAFTTT

hears for N-S Strips byhears for N-S Strips

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AREVA NP Inc.


Figure 03.08.05-30-1—Bernoulli Beam Analytical Model

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AREVA NP Inc.


Figure 03.08.05-30-2—Basemat Strips and Settlement Locations

D

U.S. EPR Final Safety Analysis Report Markups

DRAFT

U.S. EPR FINAL SAFETY ANALYSIS REPORT

Tier 2 Revision 2—Interim Page 1.8-15

2.5-7 A COL applicant that references the U.S. EPR design certification will verify that the predicted differential settlement value of ½ in per 50 ft in any direction across the foundation basemat of a Seismic Category I structure is not exceeded. Settlement values larger than this may be demonstrated acceptable by performing additional site-specific evaluations.

2.5.4.10.2 Y

2.5-8 A COL applicant that references the U.S. EPR design certification will evaluate site-specific information concerning the stability of earth and rock slopes, both natural and manmade (e.g., cuts, fill, embankments, dams, etc.), of which failure could adversely affect the safety of the plant.

2.5.5 Y

2.5-9 A COL applicant that references the U.S. EPR design certification will reconcile the site-specific soil properties with those used for design of U.S. EPR Seismic Category I structures and foundations described in Section 3.8

2.5.4.2 Y

2.5-10 A COL applicant that references the U.S. EPR design certification will investigate and determine the uniformity of the underlying layers of site specific soil conditions beneath the foundation basemats. The classification of uniformity or non-uniformity will be established by a geotechnical engineer.

2.5.4.10.3 Y

3.1-1 A COL applicant that references the U.S. EPR design certification will identify the site-specific QA Program Plan that demonstrates compliance with GDC-1.

3.1.1.1.1 Y

3.2-1 A COL applicant that references the U.S. EPR design certification will identify the seismic classification of applicable site-specific SSC that are not identified in Table 3.2.2-1.

3.2.1 Y

3.2-2 A COL applicant that references the U.S. EPR design certification will identify the quality group classification of applicable site-specific SSC important to safety that are not identified in Table 3.2.2-1.

3.2.2 Y

Table 1.8-2—U.S. EPR Combined License Information Items Sheet 10 of 54

Item No. Description Section

Action Requiredby COL

Applicant

Action Requiredby COL Holder

03.08.05-30

references the U.Sfication will invest

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structures have the capacity to support the bearing pressure with a factor of safety of 3.0 under static conditions.

2.5.4.10.2 Settlement

Safety-related structures, systems and components are housed primarily in structures supported by the foundation basemat for the NI Common Basemat Structures and independent foundation basemats for the EPGBs and the ESWBs. The design of the Seismic Category I foundations for the U.S. EPR is based on a maximum differential settlement of ½ inch per 50 feet in any direction across the basemat. Settlements within this limit will not adversely affect the function of safety-related structures, systems, or components based on the design basis for relative displacements between SSC (GDC 2).

Total settlement is dependent on site-specific conditions, construction sequence, loading conditions, and excavation and dewatering plans. It is expected that all elastic settlement and most of the consolidation settlement will occur by the time of completion of construction. There are limited interfaces between systems located on different basemats. The effects of settlement and differential settlement are considered where these interfaces occur. As described in Section 3.8.4.1.8 and Section 3.8.4.1.9, the design of safety-related buried conduits and piping is site-specific. These features will be designed for site-specific values of settlement and differential settlement expected at the interface with the foundation basemat after connections are made. Alternatively, site-specific structural features such as tunnels may be used to limit the imposition of differential settlement.

A COL applicant that references the U.S. EPR design certification will verify that the predicted differential settlement value of ½ inch per 50 feet in any direction across the foundation basemat of a Seismic Category I structure is not exceeded. Settlement values larger than this may be demonstrated acceptable by performing additional site-specific evaluations.

Section 3.8.5.7 addresses settlement monitoring.

2.5.4.10.3 Uniformity and Variability of Foundation Support Media

The U.S.EPR design considers a broad range of subsurface conditions, and the effects of these various conditions were evaluated by an extensive series of SSI analyses which addressed subsurface stratigraphy, depth-to-bedrock, shear wave velocity, and its variation with depth. While the U.S. EPR design is intended to cover a broad range of soil conditions, it is recognized that it is impractical to address all possible subsurface variations. For this reason site specific subsurface conditions will be evaluated for applicability to the U.S. EPR.

03.08.05-30

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atering plans. It is exatering plans.settlement will occur bysettlement will occ

re limited interfaces betwre limited interfaces betwsettlement and differentitlement and

ces occur. As desc As d ribed in of safety-related buried of safety-related buri

will be designed for site-e designed for site-nt expected at the interfacnt expected at the interfac

made. Alternatively, site-made. Alternativelyo limit the limi imposition of dimposition of

pplicant that references tpplicant that refectedcted Ddifferential settlemedifferential settlem

ndation basemat of a Sendation basemat oflarger than this mlarger than this

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seismic loads, the calculated minimum factors of safety are less than the values provided in NUREG-0800, for overturning and sliding of the NI Common Basemat Structure. The acceptability of these calculated values is further addressed in the following section for the NI Common Basemat Structure foundation basemat.

Acceptance criteria for soil conditions for the media supporting Seismic Category I foundations are addressed in Section 2.5.

Acceptance criteria for settlement for Seismic Category I foundations are addressed in Section 2.5.

Additional acceptance criteria for critical areas of these structures are described in Appendix 3E.

An as-built report is prepared to summarize deviations from the approved design and confirm that the as-built Seismic Category I foundations are capable of withstanding the design basis loads described in Section 3.8.5.3 without loss of structural integrity or safety-related functions.

A COL applicant that references the U.S. EPR design certification will evaluate site-specific methods for shear transfer between the foundation basemats and underlying soil for site-specific soil parameterscharacteristics that are not within the envelope of the soil parameters specified in Section 2.5.4.2.

3.8.5.5.1 Nuclear Island Common Basemat Structure Foundation Basemat

Appendix 3E provides details of the design of the NI Common Basemat Structure foundation basemat critical areas.

Maximum soil bearing pressures under the NI Common Basemat Structure foundation basemat are 22,000 pounds per square foot for static loading conditions, and 34,56026,000 pounds per square foot for dynamic loading conditions.

In addition to forces and moments due to soil spring analyses, the NI Common Basemat Structure foundation basemat for the U.S. EPR plant considers other settlement effects (e.g., consolidation, construction sequence, lateral soil variability) by assuming a flexural settlement of 0.25 inches in 50 feet. The effects of other flexural settlement of the NI foundation basemat are investigated through manual calculations by representing the basemat as one foot wide fixed-fixed Bernoulli beams displaced at one support. The total differential displacement at the support of each strip is obtained by linearly extrapolating 0.25 inches per 50 feet for the entire length of the strip. The resulting values of moment and shear are calculated using an effective concrete modulus of elasticity adjusted for creep relaxation. The maximum values for moment and shear are applied over the entire length of the strip. These moment and shear values are then manually included with the results of the ANSYS model to provide a

03.08.05-30 DRAFTviations from tviationTfoundations are capafoundations Tn 3.8.5.3 without loss of sn 3.8.5.3 without los

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arameterseterAcharacteristicscharacteristicsAecified in Section 2.5.4.2.ecified in Section 2.5.4.2.

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design that accounts for flexure and shear associated with the soil spring analysis and flexure and shear associated with other settlements.

The effects of tilt settlement on the soil bearing pressure were investigated by rotating the ANSYS model of the Nuclear Island about the East-West axis. The increases in soil bearing pressure within the NI Common Basemat were negligible.

Differential settlements and local settlements within the perimeter of the foundation are not likely to affect the structures, systems, or components due to the extremely thick foundation stiffened by numerous shear walls. The combined stiffness allows the NI Common Basemat Structure foundation basemat to bridge potential foundation irregularities.The NI Common Basemat Structure foundation basemat for the U.S. EPR plant design can accommodate tilt settlements up to 0.5 inches in 50 feet in any direction across the basemat, as described in Section 2.5.4.10.2. Differential settlements and local settlements within the perimeter of the foundation, are not likely to affect the structure, systems, or components due to the extremely thick foundation stiffened by numerous shear walls. The combined stiffness allows the NI Common Basemat Structure foundation basemat to bridge potential foundation irregularities.

For worst-case loading combinations on the NI Common Basemat Structure foundation basemat, the conservativetime history methodology used to calculate sliding and uplift safety factors due to seismic loadings is described in Section 3.8.5.4.2. The calculated values meet the requirements of Table 3.8-11., as provided in Table 3.8-16, are sufficiently small that they can be considered inconsequential with respect to sliding and overturning.

For worst-case loading combinations on the RB internal structures basemat above the containment liner, the minimum safety factor against sliding is 0.16 occurring for soil case 2sn4u, based solely on friction between the liner and the supporting concrete. Because friction will not prevent sliding, the surrounding concrete haunch wall is designed with sufficient capacity to resist the total base shear force. The minimum safety factor against overturning is 1.22 occurring for soil case 2sn4u.

3.8.5.5.2 Emergency Power Generating Buildings Foundation Basemats

Appendix 3E provides details of the design of the EPGB foundation basemats critical sections.

Evaluation of the EPGB foundation basemat for maximum bearing pressures under static and dynamic loading conditions, settlements, flotation, sliding, and overturning will be performed to confirm that applicable acceptance criteria are met.Maximum soil bearing pressures under the EPGB foundation basemat are 3,800 pounds per square foot for static loading conditions, and 10,800 pounds per square foot for dynamic

03.08.05-30

DRAFT

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2010/07/14 Areva EPR DC - DRAFT Response to U.S. EPR ... · ACI SP 152-3 state.” ACI SP 15 the...

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