Information Notice 2011-05, Tohoku-Taiheiyou-Oki Earthquake Effects on Japanese Nuclear Power Plants

Tohoku-Taiheiyou-Oki Earthquake Effects on Japanese Nuclear Power Plants

ML110760432
Person / Time
Issue date:	03/18/2011
From:	Laura Dudes, Mcginty T Division of Construction Inspection and Operational Programs, Division of Policy and Rulemaking
To:
Bowman E, NRR/DPR, 415-2963
References
IN-11-005
Download: ML110760432 (6)

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NEW REACTORS

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, DC 20555-0001 March 18, 2011 NRC INFORMATION NOTICE 2011-05: TOHOKU-TAIHEIYOU-OKI EARTHQUAKE

EFFECTS ON JAPANESE NUCLEAR POWER

PLANTS

ADDRESSEES

All holders of or applicants for operating licenses for nuclear power reactors under the provision

of Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Domestic Licensing of

Production and Utilization Facilities, except those who have permanently ceased operations

and have certified that fuel has been permanently removed from the reactor vessel.

All holders of or applicants for a standard design certification, standard design approval, manufacturing license, limited work authorization, early site permits or combined license issued

under 10 CFR Part 52, Licenses, Certifications and Approvals for Nuclear Power Plants.

PURPOSE

The U.S. Nuclear Regulatory Commission (NRC) is issuing this information notice (IN) to inform

addressees of effects of the Tohoku-Taiheiyou-Oki Earthquake on nuclear power plants in

Japan. The NRC expects that recipients will review the information for applicability to their

facilities and consider actions, as appropriate, to avoid similar problems. Suggestions contained

in this IN are not NRC requirements; therefore, no specific action or written response is

required.

DESCRIPTION OF CIRCUMSTANCES

The following summary of events is provided based on the best information available at this

time. The situation in Japan regarding recovery efforts for the Fukushima Daiichi Nuclear

Power Station continues to evolve on an hourly basis.

On March 11, 2011, the Tohoku-Taiheiyou-Oki Earthquake occurred near the east coast of

Honshu, Japan. This magnitude 9.0 earthquake and the subsequent tsunami caused significant

damage to at least four of the six units of the Fukushima Daiichi nuclear power station as the

result of a sustained loss of both the offsite and on-site power systems. Efforts to restore power

to emergency equipment have been hampered or impeded by damage to the surrounding areas

due to the tsunami and earthquake.

Units 1 through 3, which had been operating at the time of the earthquake, scrammed

automatically, inserting their neutron absorbing control rods to ensure immediate shutdown of

the fission process. Following the loss of electric power to normal and emergency core cooling

systems and the subsequent failure of back-up decay heat removal systems, water injection into

the cores of all three reactors was compromised, and reactor water levels could not be

maintained. Tokyo Electric Power Company (TEPCO), the operator of the plant, resorted to

injecting sea water and boric acid into the reactor vessels of these three units, in an effort to

cool the fuel and ensure the reactors remained shutdown. However, the fuel in the reactor

cores became partially uncovered. Hydrogen gas built up in Units 1 and 3 as a result of

exposed, overheated fuel reacting with water. Following gas venting from the primary

containment to relieve pressure, hydrogen explosions occurred in both units and damaged the

secondary containments. It appears that primary containments for Units 1 and 3 remain

functional, but the primary containment for Unit 2 may be damaged. TEPCO cut a hole in the

side of the Unit 2 secondary containment to prevent hydrogen buildup following a sustained

period when there was no water injection into the core.

In addition, Units 3 and 4 have low spent fuel pool (SFP) water levels. Efforts continue to

supply seawater to the SFPs for Units 1 through 4 using various methods. At this time, the

integrity of the SFPs for Units 3 and 4 is unknown.

Fukushima Daiichi Units 4 through 6 were shutdown for refueling outages at the time of the

earthquake. The fuel assemblies for Unit 4 had been offloaded from the reactor core to the SFP.

The SFPs for Units 5 and 6 appear to be intact, but the temperature of the pool water appears

to be increasing. Emergency power is available to provide cooling water flow through the SFPs

for Units 5 and 6.

The Japanese Government ordered an evacuation out to 20 km for the area surrounding

Fukushima Daiichi. Residents out to 30 km were ordered to shelter in place.

The damage to Fukushima Daiichi nuclear power station appears to have been caused by

initiating events outside of the design basis for the facilities.

BACKGROUND

10 CFR Part 50, Appendix A, General Design Criteria for Nuclear Power Plants, General

Design Criterion (GDC) 2, Design Bases for Protection against Natural Phenomena, or similar

appropriate requirements in the licensing basis for a reactor facility, requires that structures, systems, and components (SSCs) important to safety be designed to withstand the effects of

natural phenomena such as earthquakes, tornadoes, hurricanes, floods, tsunami, and seiches

without loss of capability to perform their safety functions. The design bases for these SSCs

reflect: (1) appropriate consideration of the most severe of the natural phenomena that have

been historically reported for the site and surrounding area, with sufficient margin for the limited

accuracy, quantity, and period of time in which the historical data have been accumulated, (2)

appropriate combinations of the effects of normal and accident conditions with the effects of the

natural phenomena, and (3) the importance of the safety functions to be performed. As a result of the terrorist events of September 11, 2001, the NRC issued EA-02-026, Order for

Interim Safeguards and Security Compensatory Measures (the ICM Order) dated February 25,

2002. The ICM Order, which is designated as Safeguards Information (SGI), modified then- operating licenses for commercial power reactor facilities to require compliance with specified

interim safeguards and security compensatory measures. Section B.5.b of the ICM Order

requires licensees to adopt mitigation strategies using readily available resources to maintain or

restore core cooling, containment, and SFP cooling capabilities to cope with the loss of large

areas of the facility due to large fires and explosions from any cause, including beyond-design- basis aircraft impacts.

By letter, dated February 25, 2005, the NRC staff provided guidance for implementing Section

B.5.b of the ICM Order. This guidance, designated as SGI, included best practices for

mitigating losses of large areas of the plant and measures to mitigate fuel damage and minimize

releases. Following issuance of the B.5.b Phase 1 Guidance, the NRC staff conducted

inspections at operating reactor sites using Temporary Instruction (TI) 2515/164 (SGI) and

subsequently TI 2515/168 (SGI) to ensure compliance with Section B.5.b of the ICM Order.

In December 2006, the Nuclear Energy Institute (NEI) issued NEI 06-12, Revision 2, B.5.b

Phase 2 & 3 Submittal Guideline. NEI 06-12 is designated for Official Use Only - Security

Related Information (OUO-SRI). The NRC endorsed NEI 06-12, Revision 2, by letter dated

December 22, 2006, also designated OUO-SRI, as an acceptable means for developing and

implementing the mitigation strategies requirement in Section B.5.b of the ICM Order. NEI 06-

12, Revision 2, provides guidance for implementing a set of strategies intended to maintain or

restore core cooling, containment, and SFP cooling capabilities under the circumstances

associated with the loss of a large area of the plant due to explosions or fire. NEI 06-12 provides guidance in the following areas:

• Adding make-up water to the SFP,

• Spraying water on the spent fuel,

• Enhanced initial command and control activities for challenges to core cooling and

containment, and

• Enhanced response strategies for challenges to core cooling and containment.

The specific strategies covered in NEI 06-12, Revision 2, were developed based on the results

of assessments conducted at currently licensed power reactor facilities for the purpose of

enhancing plant specific mitigation capability for damage conditions caused by a large explosion

or fire. These assessments identified a wide spectrum of potential plant specific strategies.

NEI 06-12, Revision 2, specifies one set of strategies applicable to all pressurized-water

reactors and another set applicable to all boiling-water reactors. Both sets are derived from the

results of the plant specific assessments.

The B.5.b Phase 1 Guidance and NEI 06-12, Revision 2, were used by each licensee in

preparing information submitted to the NRC that describes a plant specific approach to

implementing mitigating strategies and supports each plant specific license condition. The NRC

staff has completed its review of the information submitted by each licensee, as well as information obtained during prior NRC inspections, and has issued an OUO-SRI safety

evaluation (SE) that documents the bases for its approval of the license condition for each

facility. The SE issued for each licensee includes regulatory guidance in Section 3.0 of

Appendix A, Phase 1 Assessment, that recites the generic B.5.b Phase 1 Guidance of

Reference 3, as clarified in TI 2515/168, in a form that is designated OUO-SRI rather than SGI.

By publishing new requirements in the Federal Register dated March 27, 2009 (74 FR 13926),

the NRC amended 10 CFR Part 50, 10 CFR Part 52, Licenses, Certifications, and Approvals

for Nuclear Power Plants, and 10 CFR Part 73, Physical Protection of Plants and Materials.

This rulemaking added paragraph (i) to 10 CFR 50.34, Contents of Applications; Technical

Information, and paragraph (d) to 10 CFR 52.80 Contents of Applications; Additional

Technical Information, to require submittal of a description and plans for implementation of the

guidance and strategies intended to maintain or restore core cooling, containment, and spent

fuel pool cooling capabilities under the circumstances associated with the loss of large areas of

the plant due to explosions or fire as required by § 50.54(hh)(2) of this chapter. This

rulemaking also added 10 CFR 50.54(hh)(2) to impose the same mitigating strategies

requirements on all reactor applicants and licensees as those imposed by the ICM Order and

associated license conditions. The Statement of Considerations for this rulemaking specifically

noted that the requirements in 10 CFR 50.54(hh) are intended to address certain events that are

the cause of large fires and explosions that affect a substantial portion of the nuclear power

plant and are not limited or directly linked to an aircraft impact. In addition, the rule

contemplates that the initiating event for such large fires and explosions could be any number of

beyond-design basis events. Such events include natural phenomena such as those described

in GDC 2 (i.e., earthquakes, tornadoes, floods, tsunami, and seiches), without regard to the

GDC 2 provisions governing the severity of natural phenomena.

NRC regulations at 10 CFR 50.63, Loss of All Alternating Current Power, require that light- water-cooled nuclear power plants be capable of withstanding for a specified duration and

recovering from a station blackout.

DISCUSSION

The nuclear power industry has taken the actions listed below at each licensed reactor site.

Additional information is available in the NEI Fact Sheet, Industry Taking Action to Ensure

Continued Safety at U.S. Nuclear Energy Plants, dated March 16, 2011, available at

www.nei.org.

1. verification of the capability to mitigate conditions that result from severe adverse events, including the loss of significant operational and safety systems due to natural events, fires, aircraft impact and explosions

2. verification of the capability to mitigate a total loss of electric power to a nuclear power

plant

3. verification of the capability to mitigate flooding and the impact of floods on systems

inside and outside the plant 4. identification of the potential for loss of equipment functions during seismic events

appropriate for the site and the development of mitigating strategies to address potential

vulnerabilities

NRC assessment of the implications of beyond design-basis natural phenomena is continuing

as more information becomes available. The NRC staff is currently developing a TI to guide

staff in performing independent assessments of nuclear power plant readiness to address

beyond design-basis natural phenomena under the Reactor Oversight Process. The NRC is

considering additional generic communications and additional action including requesting

operating plants to provide specific information relating to their facilities to enable the NRC staff

to complete a regulatory assessment of beyond design basis phenomena.

PAPERWORK REDUCTION ACT STATEMENT

This Information Notice does not contain any information collections and, therefore, is not

subject to the requirements of the Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq.).

Public Protection Notification

The NRC may not conduct or sponsor, and a person is not required to respond to, a request for

information or an information collection requirement unless the requesting document displays a

currently valid Office of Management and Budget control number.

CONTACT

S

This information notice requires no specific action or written response. Please direct any

questions about this matter to the technical contact listed below or the appropriate Office of

Nuclear Reactor Regulation (NRR) project manager.

/RA by MShuaibi/ /RA/

Laura A. Dudes, Director Timothy J. McGinty, Director

Division of Construction Inspection, Division of Policy and Rulemaking

and Operational Programs Office of Nuclear Reactor Regulation

Eric E. Bowman, NRR

301-415-2963 e-mail: Eric.Bowman@nrc.gov

Note: NRC generic communications may be found on the NRC public Web site, http://www.nrc.gov, under Electronic Reading Room/Document Collections. 4. identification of the potential for loss of equipment functions during seismic events

appropriate for the site and the development of mitigating strategies to address potential

vulnerabilities

NRC assessment of the implications of beyond design-basis natural phenomena is continuing

as more information becomes available. The NRC staff is currently developing a TI to guide

staff in performing independent assessments of nuclear power plant readiness to address

beyond design-basis natural phenomena under the Reactor Oversight Process. The NRC is

considering additional generic communications and additional action including requesting

operating plants to provide specific information relating to their facilities to enable the NRC staff

to complete a regulatory assessment of beyond design basis phenomena.

PAPERWORK REDUCTION ACT STATEMENT

This Information Notice does not contain any information collections and, therefore, is not

subject to the requirements of the Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq.).

Public Protection Notification

The NRC may not conduct or sponsor, and a person is not required to respond to, a request for

information or an information collection requirement unless the requesting document displays a

currently valid Office of Management and Budget control number.

CONTACT

S

This information notice requires no specific action or written response. Please direct any

questions about this matter to the technical contact listed below or the appropriate Office of

Nuclear Reactor Regulation (NRR) project manager.

/RA by MShuaibi/ /RA/

Laura A. Dudes, Director Timothy J. McGinty, Director

Division of Construction Inspection, Division of Policy and Rulemaking

and Operational Programs Office of Nuclear Reactor Regulation

Office of New Reactors

Eric E. Bowman, NRR

301-415-2963 e-mail: Eric.Bowman@nrc.gov

Note: NRC generic communications may be found on the NRC public Web site, http://www.nrc.gov, under Electronic Reading Room/Document Collections.

ADAMS Accession Number: ML110760432

• by e-mail

OFFICE NRR/DPR/PGCB TECH EDITOR* NRR/DIRS/D* NRR/DE/D* NSIR/DSP*

NAME EBowman KAzariah-Kribbs BWestreich PHiland(GWilson for) RCorreia

DATE 03/17/2011 03/17/2011 03/17/2011 03/17/2011 03/17/2011 OFFICE NRO/DCIP/CAEB* DPR/PGCB/LA DPR/PGCB/BC NRO/DCIP/D NRR/DPR/D

NAME TFrye CHawes SRosenberg LDudes(MShuaibi for) TMcGinty

DATE 03/18/2011 03/17/2011 03/17/2011 03/18/2011 03/18/2011 OFFICIAL RECORD COPY