Events at Fukushima NPP in Japan

New impetus to review NPPs safety worldwide

INES Level 7

Impact of

extreme external

events and their

combinations

2

KNOWLEDGE

BASE

TECHNOLOGY

(technical safety

ensuring)

DEFENCE-IN-DEPTH

PRINCIPLE

Multiplicity of safety

barriers

Variety of levels for

protection barriers:

–prevention of accidents

–mitigation of accident

consequences

(accident management)

LEGISLATION

Federal laws

(responsibility

principles)

System of rules and

regulation

State licensing

authority

(independent

regulation)

SAFETY CULTURE - Alignment of priorities

- Human factor

Safety fundamentals

3

The safety fundamentals are correct and shall

not be subject to any revisions

Prolonged loss of external and internal

power and water supply

Failure to provide

external support timely

Inefficiency of the severe accident

management efforts made by personnel

Very low probable events and

their combination (deterministic

approach)

Off-site

radiological

impact on the

public and the

environment

shall be

excluded

4

The key criterion of success

is the recovery of power

supply and water feed for

reactor cooling down

implemented within first

hours after the total blackout

Operating organization, governmental and local

authorities, international organizations and the public

shall be timely informed about a NPP event. Provision of

external support from state level as well as from

international community shall be ensured.

At each power unit there

shall be available a reserve of

engineering means protected

against possible damage by a

natural disaster, which ensure

power and water supply for

purposes of reactor and fuel

pool cooling

Personnel, managers at NPP and in the Operating

organization shall be focused on prompt actions

aimed at accident prevention and mitigation of severe

accidents consequences

!

6

Deterministic experience related to BDBA consequences

evaluation that has been accumulated beforehand

Additional equipment failures

Methodology for Russian NPPs safety

status analysis as regard to emergencies

Upgrading works aimed at safety improvement of NPPs

(incl. BDBA management) have been implemented

during last 10 – 15 years

Vulnerabilities and list of hypothetic initial events have

been identified for each NPP

Implementation of supplementary measures aimed at

enhancement of NPP capability to operate in a

standalone mode (up to 5-10 days) is needed

The countermeasures considered in designs of the

operating NPPs cover not all BDBA initial events

(combination of 2 or more failures was not considered)

7

Analytical report on the reviewed scenarios of

abnormal external event impacts on Russian NPPs;

Measures aimed at mitigation of beyond-design-

basis accident consequences at NPPs:

Operative (1 to 4 months);

Short-term (1 year);

Medium-term (1 to 2 years);

Long-term (3 to 7 years)

8

9

Reviews of safety status with involvement of General Designer, Architect Engineer and Scientific Supervisor have been performed for all operating NPPs in Russia with all credible extreme events. For each NPP a separate report has been elaborated.

Supplementary safety improvement measures have been developed for each NPP

The reports on safety analysis of a NPP under extreme external impacts had been submitted to the regulatory body (Rostechnadzor) till 15.08.2011

As per results of own review, Rostechnadzor had approved the reports on safety analysis of a NPP under extreme external impacts in November 2011

Operative measures

Focused checks and analysis of NPP safety provisions for extreme impacts

Extraordinary plant staff emergency drills as per BDBA scenarios

Extraordinary tests of safety systems equipment with EDG start-up

Increased number of regularly performed emergency drills related to personnel actions in case of a BDBA

10

Short-term measures

To identify backup (additional) water (borated water) sources for purposes of heat removal from the core, fuel pool and SNF storage facilities, and to introduce procedures of their use into the operating documentation

To develop a generic list of supplementary mobile equipment per a unit

To perform additional quick studies and analysis of NPP seismic zoning documentation, and calculation analysis of seismic impacts on the reactor unit, fuel pools and on-site SNF storage facilities

To perform analysis of emergency instructions and guidelines as regard to sufficiency of accident management actions to be performed by staff

To elaborate technical specifications on the supplementary design solutions

11

Supplementary equipment delivery to NPPs

Full-scope implementation of the supplementary design solutions

Long-term measures

Medium-term measures

Adjustment of emergency instructions and accident

guidelines after implementation of the planned measures

Development of the design documentation and

beginning of implementation of the supplementary design solutions

Adjustment of emergency instructions and accident

guidelines after the equipment delivery to NPPs

Development of severe accident management guidelines 12

Generic set of mobile equipment for BDBA management

purposes, per a Unit

29%

89%

20%

74%

71%

11%

80%

26%

Mobile Diesel

Generator Units

(MDGU) 2.0 MW

Mobile Diesel

Generator Units

(MDGU) 0.2 MW

Mobile Pump

Units (MPU)

Motor-driven

Pumps

Supplied

May 2012

80 pcs.

35 pcs.

36 pcs.

31 pcs.

(9шт.) (22 шт.)

(59 шт.)

(32 шт.)

(7 шт.)

13

To identify supplementary schemes of power supply from emergency diesel generators to the loads:

power control;

control systems.

To identify supplementary water sources and schemes of water supply to reactor, steam generators and SNF storage pools using diesel-driven / motor-driven pumps;

To implement a system for SNF pool metal liner cooling.

Implementation of hydrogen monitoring and afterburning systems;

Implementation of a system for emergency gas release from the reactor containment.

14

Power supply securing

Heat removal securing

Explosion safety ensuring

Provision for reactor scram by the automated emergency

protection system in case of earthquake;

Improvement of seismic resistance of plant equipment,

pipelines and civil structures.

NPP equipping with emergency I&C devices designed for

operation under BDBA conditions;

Improvement of protection of plant MCRs and ECRs;

Development of Severe Accident Management Guidelines.

15

Seismic resistance ensuring

Provisions for management and control

Upgrading the communication

infrastructure of the Engineering Support

Center, the Crisis Center and NPPs;

Establishment of a regional Crisis Center of

WANO Moscow Center.

16

Analysis of scenarios and radiological consequences of

severe accidents, with the goal of implementation of:

• the RPV cooling system;

• the system for emergency gas release from the reactor

containment;

• the emergency I&C;

• other supplementary design solutions.

Calculation of maximum possible seismic impacts at the NPP

locations, on the basis of modern computational models.

17

Federal safety requirements are met with the

compensatory measures taken into account;

For Russian NPPs in operation, analysis of their

defense-in-depth resistance has been carried out;

Measures aimed at enhancement of operating NPPs

resistance to extreme external impacts have been

developed and are implemented;

For Russian NPPs under construction or in designing,

it is planned to perform analysis of their resistance to

extreme external impacts.

18 Final slide

19