Post-quake status of the Kashiwazaki-Kariwa Nuclear Power Station (Report #12)
-The status of consideration by the Nuclear and Industrial Safety AgencyJanuary 9, 2008
Rev.1
Japan Nuclear Technology Institute
The Nuclear and Industrial Safety Agency (NISA) of the Ministry of Economy, Trade and Industry(METI) established the “Nuclear Facility Investigative Taskforce in the Niigataken Chuetsu-oki
Earthquake” (Headed by Professor Haruki Madarame of the University of Tokyo’s Graduate Schoolof Engineering) under the Nuclear and Industrial Safety Subcommittee of the METI Advisory
Committee for Natural Resources and Energy to examine facts to identify the impact of the
Niigataken Chuetsu-oki Earthquake on the Kashiwazaki-Kariwa Nuclear Power Station, andsummarize future tasks and desirable responses of the national government and nuclear energy
operators based on the lessons learned from the said Earthquake. This Report #12 describes the
progress of deliberations by the Taskforce.

<Summary>+ The Taskforce has the following Working Groups summarize and examine future tasks, anddeliberates on their findings. (See 1.)- Working Group on in-house fire-fighting and information liaison / provision in the Niigataken
Chuetsu-oki Earthquake- Subcommittee on anti-quake structural designs- Working Group on nuclear plant administration and assessment of facility integrity+ The ”Working Group on in-house fire fighting and information liaison / provision in the
Niigataken Chuetsu-oki Earthquake” compiled a report (draft) on specific measures foraddressing issues that came to light in relation to the transformer fire and the handling of
information liaison. The WG presented the report to the Taskforce on December 19 fordeliberation and subsequent approval. The report will be made open for comments from
December 21 to January 25, and put to further deliberations by the Taskforce on possible
revisions reflecting the comments gathered.
Each of 10 electric power companies and Japan Nuclear Fuel Limited also presented its
policy on immediate initiatives regarding in-house fire fighting and information liaison /provision. All the initiatives cited were in line with the Taskforce report, and included ones
that had already been in place with content reflecting measures listed in the report. Eachcompany aims to complete the initiatives by the end of 2008 or the next two periodical
inspection according to its situation of plant operation.(See 2.(1))+ The integrity assessment of reactor buildings, following the earthquake, indicated that thebuildings were generally within the elastic region.(See 2.(2))+ The Taskforce meeting on December 9 heard a report that the Kashiwazaki-Kariwa Nuclear
Power Station had all the nuclear safety functions secured at the time of the earthquake.
The Taskforce also heard a report about plant administration issues, although minor innature, that have been identified as beneficial for ensuring safety of nuclear power stations,and how such issues are addressed.(See 2.(3))+ The Taskforce heard the basic policy on the assessment of facility integrity, which represented
summary of deliberations by the “Working Group on nuclear plant administration andassessment of facility integrity”. Based on the basic policy, NISA issued a written instruction,
dated November 9, that TEPCO draw up an inspection and assessment plan for each of thereactor units at the Kashiwazaki-Kariwa Nuclear Power Station, and submit it to NISA.

In response, TEPCO submitted an inspection and assessment plan for Unit 7 of theKashiwazaki-Kariwa Nuclear Power Station, dated November 27. NISA confirmed that theplan covered all requirements presented in the instruction.(See 2.(4))
TEPCO intends to complete “seismic response analysis” and “facility inspections” on Unit 7,
referred to in the plan, by March and May next year respectively, and use the information
obtained to conduct a “general assessment on facility integrity” by June next year. The
company also plans to draw up similar inspection and assessment plans for Units 1 to 6. (Seethe TEPCO press release dated November 27, 2007 for details.)<Details>
1. Deliberation structure and issues for examination (See the attachment for details)
The Taskforce has the following Working Groups summarize and examine future tasks, anddeliberates on their findings submitted.
Subcommittee / Working Group

Tasks for examination

Working Group on in-house firefighting and information liaison /provisionintheNiigataken
Chuetsu-oki Earthquake
Subcommitteeonanti-quake
structural designs (Existing committee
under the Nuclear and Industrial
Safety Subcommittee)
Working Group on nuclear plant
administration and assessment offacility integrity

Examining how nuclear plant operators should
conduct in-house fire-fighting, report information
within themselves and provide information to local
communities in the event of an earthquake
Assessing anti-quake safety based on the insightobtained from the Niigataken Chuetsu-oki Earthquake

Examining nuclear reactors’ administration status at
the time of the Niigataken Chuetsu-oki Earthquake,as well as the facilities’ integrity and future handling

2. Deliberation status of the Taskforce
The Taskforce has convened four times since the first meeting on July 31. The deliberations at
the fourth meeting, convened on December 19, went as described below:(1) The Taskforce deliberated on and approved a report compiled by the ”Working Group on in-housefire fighting and information liaison / provision in the Niigataken Chuetsu-oki Earthquake”. The
table below gives the outlines of the report. The report will be made open for comment from
December 21 to January 25, and put to further deliberation by the Taskforce on possible revisions
reflecting the comments gathered.
Each of 10 electric power companies and Japan Nuclear Fuel Limited also presented its policy
on immediate initiatives regarding in-house fire fighting and information liaison / provision. All
the initiatives cited were in line with the Taskforce report, and included ones that had alreadybeen in place with content reflecting measures listed in the report. Each company aims tocomplete the initiatives by the end of 2008 or the next two periodical inspection according to its
situation of plant operation (See the TEPCO press release issued on December 20, 2007 for details
of TEPCO.)<In-house system for fire fighting>
Item
a.

Tasks
identified inthetransformer

Findings- Lack of sufficient manpower for conducting initial fire-fighting efforts- Damage to or lack of fire-fighting equipment- Delay in reporting the fire to the Fire Department- Lack of training among workers involved in initial fire-fighting efforts

fireb. Allocation of - The in-house fire-fighting corps is assigned the role of using the company’sroles between
own defensive means to handle areas that the Fire Department may findthe in-housedifficulty in covering due to time constraints. The corps conducts initial
fire-fighting
fire-fighting efforts to minimize damage.
corps and the - In a large-scale earthquake and other emergency, there may be times whenFire
the Fire Department cannot fulfill its normal operations. The in-house
Department
fire-fighting corps must have the ability to handle an anticipated level offire.
c.
Specific - Enhancing the initial fire-fighting system (conducting round-the-clock
measures formonitoring, securing around ten workers as reserve staff for initialfundamentall
operations, etc.)
y reinforcing - Improving the reliability of fire-fighting equipment (ensuring anti-quake
the in-house performance, achieving diversity / multiplexing, etc.)
fire-fighting- Improving the reliability of associated facilities essential for fire-fighting
systemoperations (establishing a direct communications line with the Fire
Department at the Main Control Room, securing anti-quake resilience forthe emergency management office, etc.)- Implementing and reviewing practical drills in coordination with the Fire
Department (drawing up a plan for fire-fighting activities, applying the
PDCA cycle in drills and their reviews, etc.)<System for information liaison / provision>
Item

Findings

Tasks
on
information
liaison / provisionattheKashiwazaki-Kari
wa Nuclear Power
Stationb. Specific measuresfor ensuring swift
andaccurate
liaison / provisionof information- Lack of sufficient initial response- Difficult-to-understand expressions used
- Lack of sufficient considerations to the recipients of information- Compromise of information liaison attributable to problems withassociated facilities or lack of protocols on the part of the power company- Problems surrounding NISA’s on-site system for information gathering,
liaison and provision- Using diverse means to deliver information swiftly to local residents,
etc. (issuing press releases from the initial response stage, using various
means to repeatedly provide information, etc.)- Adjusting expressions to provide information in an easy-to-understandmanner (citing daily life situations as metaphors, swiftly giving atentative rating to an event according to the INES scale, etc.)- Reinforcing the government’s information liaison / provision systemwith focus on on-site operations (swiftly dispatching NISA’s senior staff
to the site, building a system that automatically gathers important
information, etc.)- Having nuclear energy operators develop communications facilities andsystems that can withstand a major earthquake (improving the
installation of such equipment with due considerations toearthquakes, securing staff for measuring and analyzing the leakageof radioactive substances, etc.)- Implementing practical drills and trainings (conducting trainings anda.

examination under the partnership of NISA, local government andnuclear energy operators)(2) The “subcommittee on anti-quake structural designs” reported the following as the status of its
activities:
a. The integrity assessment of reactor buildings, following the earthquake, indicated that thebuildings were generally within the elastic region. The Subcommittee also summarized theapproach to selecting parameters used in the analysis, and explained the concept ofauxiliary walls employed in the analysis.
b. TEPCO presented its seismic observation records and reported its plan for conducting
geological surveys in and around the power station premises.
c. TEPCO presented its interim assessment on the marine sonic prospecting.
(3) In regard to the operational / administration status of the Kashiwazaki-Kariwa Nuclear Power
Station at the time of the earthquake, the Taskforce was presented with a report by the “Working
Group on nuclear plant administration and assessment of facility integrity” on its findings overwhether the power station secured the nuclear safety functions of “Shut Down”, “Cool” and“Contain”, and what future tasks and responses should be addressed in plant operation /administration to help assure further safety of the power station. The outlines of the report are
as detailed below:<Assessment on to what extent each of the nuclear safety functions was secured at the time of theearthquake>
Functiona.

ResultReasonShut Secured - At the nuclear reactors that were operational or being started up at the
Downtime of the earthquake, the detection of “large seismic acceleration”
set off a scram signal, which resulted in swift full insertion of allcontrol rods. All operations were implemented appropriately
through to the confirmation of sub-criticality.
- The safety of the reactors that were shut down at the time of theearthquake (Unit 5 and Unit 6) was secured with all control rods infull insertion, and no significant fluctuations observed in the Source
Range Neutron Monitor.
b. Cool
Secured - At the nuclear reactors that were operational or being started up at thetime of the earthquake, all heat removal systems were working
correctly, and handled all associated operations, such as reactor
depressurization, from the reactor scram to cold shutdown.
- Although the shutdown reactors at Unit 5 and Unit 6 had fuel loaded,
all heat removal systems were working correctly. The heat removal
system for these Units’ spent fuel pool was also functioning properly.
c. Contain
Secured - The reactor water and the water of the spent fuel pools were checked
for iodine concentration at all Units. Its comparison with pre-quake
levels indicated that the earthquake caused no fuel damage.
- There was no leakage observed in the reactors’ pressure boundaries orin the reactor containment vessels.
- Radiation monitors indicated no significant increase in all areas except
for the reactor buildings’ operation floors.
- The reactor buildings maintained the negative pressure.

- No significant fluctuations were reported in the readings at monitoring
posts.

d.
Power Secured - Facilities that supply external power are required to have the seismic
supplyrating of Class C, which is the same as that for general industrial
withfacilities. In this earthquake, three external power systems (twoexternal
systems subsequently) were secured immediately after the quake
power
despite it having the intensity that surpasses the design-basis seismic
sourcesmotion.
and- The post-quake patrol and subsequently-conducted detailed
emergenc
inspections identified no damage to the emergency D/G, which has they D/Gseismic rating of “Class As”. The operation check on the same D/Gafter the earthquake also confirmed its integrity. This indicates
that, even if the earthquake caused the loss of external power sources,
the emergency D/G would have secured power supply.
(Lessons learned and future tasks)
As detailed above, the functions of “Shut Down”, “Cool”, “Contain” and “Power Supply” weresecured in the earthquake. From the perspective of further ensuring safety, it is necessary to
acknowledge and address the following lessons learned:
1) The method for simulator trainings for plant operators should be reviewed in anticipation ofcomposite events in future earthquakes.
2) The staff mobilization system, including the protocol for emergency mobilization, should be
developed and reinforced so as to conduct plant operations and on-site checks
simultaneously in emergency.
3) The emergency D/G should undergo a regular test as soon as the preparation is completed,regardless of its normal frequency for routine tests, from the perspective of ensuring power
supply to the plants.
<Assessment of non-conformities associated with the earthquake>
It is beneficial to identify minor events and use the information to apply preventive measuresat other nuclear power stations. All non-conformities (3,100 events) were examined to identify
ones that could be beneficial for preventive purposes in terms of the safety functions of “ShutDown”, “Cool” and “Contain.
Event

Description

a. Damage to theinsulationmaterialforthe boric acidsolution
injectionsystemb. Evacuation ofworkers fromradiologicallycontrolled- The earthquake shifted a heavy item, which subsequently came in contact
with the piping for the boric acid solution injection system laid in theroom, and damaged the insulation material covering the piping.
- Although the incident did not damage the piping of the boric acid solution
injection system itself, there was a possibility that the heavy item could
have damaged other piping with a high level of importance in nuclear
safety.
- The earthquake caused a failure of six of the seven monitors, used to
examine radiation contamination of plant operators as they leave aradiologically controlled area.
- After the earthquake, approximately 400 workers in the radiologicallyareas after theearthquake

controlled areas of Unit 1 were ordered to evacuate, and rushed to the only
available radiation monitor. The radiation control staff had to let theworkers leave without undergoing a contamination check through themonitor from the perspective of human safety.
- The workers were in areas where the level of contamination was kept
below the legal limit. Their contamination therefore did not exceed the
maximum surface contamination level stipulated by law. However, nocontamination checks were conducted following their evacuation to a safe
location.
c. Positions of - While fuel was transported from the reactor to the spent fuel pool at Unit
fuel assemblies
5 (which was in the shut-down state at the time of the earthquake), it waswhen loaded infound that the fuel assemblies had been dislodged from the supporta reactor
fittings on the underside.
- The records taken during fuel loading indicated that the applicable fuelassembly had the mounting position (vertical) approx. 25mm higher thanother assemblies. TEPCO recorded the mounting positions of all fuelassemblies, but did not examine whether the positions were within a
specific range.
(Lessons learned and future tasks)
Other nuclear power stations must recognize and address the following issues, in addition tolessons learned from non-conformities disclosed by TEPCO as items that require safety
considerations:1) The items in temporary storage for use in , must be affixed properly so that they would not
damage important equipment in terms of nuclear safety in the event of an earthquake.
2) There should be an emergency protocol, stipulating where workers should gather after
evacuating from radiologically controlled areas in an earthquake, and how their surface
contamination level should be gauged.
3) Power stations should control the mounting locations (vertical) of fuel assemblies in fuelloading, and check whether they are properly mounted.
(4) The Taskforce heard the basic policy on the assessment of facility integrity, which represented
summary of deliberations by the “Working Group on nuclear plant administration and assessmentof facility integrity” and its sub-Working Group.
<Basic policy on integrity assessment>a. Inspection
analysis- Important facilities in terms of nuclear safety (Class 1 facilities inimportance-based classification, Class A / As facilities in seismic
design classification and other facilities that could affect thesefacilities) should be subject to inspections and seismic response
analysis to determine the effects of earthquakes. The findings fromsuch inspections and analysis should be combined to achieve
andcomprehensive integrity assessment.
Association should be established between the results of inspections
and findings from analysis (e.g. implementing a focal inspection in
response to the result of analysis) to examine facility integrity indetails.
- Other facilities should be inspected in relevant techniques to assess
their integrity.

b. Assessment of- Facilities at the Kashiwazaki-Kariwa Nuclear Power Station, which
seismic impact on
was struck by the Niigataken Chuetsu-oki Earthquake, are required
facilities based on
to contain its overall structural deformation within the elastic region,
theresultsofand maintain their respective functions required in terms ofinspections
andengineering standards, so as to ensure engineering conformance.
analysisPresence of damage that could affect the facilities’ structures orfunctions required by engineering standards
No damage identified in
Damage identified in
inspections
inspections
Resultof
Elastic
analysis
The facility has integrity.
state
conducted
withcurrently
available
Detailed
examinationistechniques
Beyondrequiredwithadditional
based on floor the elastic inspections
andanalysis
response data state
incorporating
realisticobtainedinconditions (*)
thisearthquake

Repair or replacement work is
required after an investigation
into the cause of the damage.

(*)The Working Group on nuclear plant administration and assessment of facility integrity or
the sub-Working Group on the assessment of facility integrity should conduct a detailed
investigation into the integrity of the applicable facility.
<Past actions based on the above policy>a. Instruction on the planning of inspections and assessment regarding facility integrity
Based on the above basic policy, NISA issued a written instruction, dated November 9, thatTEPCO draw up an inspection and assessment plan for each of the reactor units at the
Kashiwazaki-Kariwa Nuclear Power Station, and submit it to NISA.
b. Considerations concerning the inspection and assessment plan
TEPCO submitted an inspection and assessment plan for Unit 7 of theKashiwazaki-Kariwa Nuclear Power Station, dated November 27, in response to the above
instruction. NISA confirmed that the plan covered all requirements presented in the
instruction.
<Future actions>a. About Unit 7- Conduct a safety inspection, routine check and on-site inspection to examine TEPCO’s
overall inspection process and the implementation status of individual inspections, in lightof the findings of seismic response analysis, so as to determine the validity of inspection
results.
- NISA should examine the validity of analysis methods and parameters used by TEPCO inassessing the impact of the Niigataken Chuetsu-oki Earthquake, if the methods orparameters are different from those applied in the design stage.
- Japan Nuclear Energy Safety Organization (JNES) should conduct a cross-check of theresults of seismic response analysis to verify their validity.
- Assess the facility’s general integrity based on the results of inspections / assessment by
TEPCO and other inspections mentioned above, and make a strict confirmation on whether
the facility requires repair work.
b. Application to other Units
Examine the inspection and assessment plans to be submitted by TEPCO for otherreactor Units, to verify that items specific to individual Units are reflected to the plans.
c. Summarization of judging criteria for determining the need for repair work
When the validity of inspection procedures and methods for seismic response analysis for
initial reactor units is verified, confirm the need for repair work for the applicable units
according to the aforementioned basic policy on integrity assessment, extract items that canbe applied to other units, and compile them into common judging criteria.

3. Other actions by NISA
(1) Report to the Nuclear Safety Commission of Japan (NSC)
The following information is to be reported to the NSC in its meeting on December 20, 2007.
a. WG report (draft) regarding in-house fire-fighting and information liaison / provisionb. Results of the assessment on the administration status of the Kashiwazaki-Kariwa Nuclear
Power Station at the time of the earthquake
c. Basic policy on the integrity assessment of facilities at the Kashiwazaki-Kariwa Nuclear
Power Station(2) Second investigation by the International Atomic Energy Agency (IAEA)
In a follow-up to its first investigation (August 2007), IAEA plans to conduct a second
investigation to examine subsequently-obtained information, check the progress and results ofon-going examination, and internationally disseminate information about future schedule andlessons learned. Specific content and timing of the investigation (around late January 2008) arecurrently being coordinated with IAEA.
END

Attachment

Deliberation structure and issues for examination by the “Nuclear Facility Investigative Taskforce in the Niigataken Chuetsu-oki Earthquake” under the Nuclear
and Industrial Safety Subcommittee of the METI Advisory Committee for Natural Resources and Energy
Subcommittee /Working Group

Issues for
examination

Specific issues

Working Group on 1.In-house fire-fighting(1)Examining TEPCO’s response and tasks in relation to this earthquake, and exploring an in-house fire-fighting system

in-house
fire-fighting

and future challenges for nuclear energy operators(2)Exploring an in-house fire-fighting system and fire-fighting facilities for nuclear energy operators

andinformation liaison 2.Information
liaison (1)Examining TEPCO’s response and tasks concerning radiation leakage, and exploring nuclear energy operators’ response/ provision in thesystemwithinthe system and tasks at the time of radiation leakage
Niigataken
plant operator(2)Exploring an information liaison system for nuclear energy operators
Chuetsu-oki
3.Initial
actionand (1)Examining TEPCO’s initial action in this earthquake, and exploring tasks concerning the government’s initial response
Earthquake

preparation system in
emergency

Hirotada 4.Information

Ohashi,

Graduate

SchoolofEngineering,

3rd meeting: October 11
4th meeting: November 14
5th meeting: December 7

system (including an investigation into facilities required for making the initial response system function properly)

provision (1)Investigating and exploring TEPCO’s information provision to local governments and residents

to local governments (2)Investigating and exploring the governments’ information provision to local governments and residents
and residents(3)Examining and exploring easy-to-understand press releases by the government and TEPCO (conveying a sense of
security and reducing adverse effects based on misunderstanding)

University of Tokyo
Subcommittee

1st meeting: August 27
2nd meeting: September 20(2)Exploring a liaison system for local governments, national government and nuclear energy operators (including a system
for gathering information that facilitates liaison)(Project Manager)
Professor

Meetings convened

on 1.Examining the research data of relevant organizations on this earthquake, observation data of the seismic motions and survey data used as designanti-quake

basis to determine why the seismic motions observed in this earthquake exceeded the design-basis seismic motions at the foundations of reactor

structural designs

buildings at the power station
2.Impact of thisearthquake on thesafety, and verifying their integrity

Professor emeritus
Katsumasa Abe of

Kashiwazaki-Kariwa
Nuclear Power Station(2)Examining the earthquake’s impact on equipment and piping that are deemed important in terms of anti-quake safety(The Working Group on nuclear plant administration and assessment of facility integrity is in charge of assessing the
integrity of equipment and piping that received force beyond the elastic region.)Tokyo(3)Examining the earthquake’s impact on other facilities (the facilities that the Working Group on in-house fire-fighting andinformation liaison / provision in the Niigataken Chuetsu-oki Earthquake has earmarked for the enhancement ofanti-quake resilience.)
3.Issues that should bereflected to futureanti-quake safetyassessment of theKashiwazaki-Kariwa
Nuclear Power Station

1st meeting: August 24(1)Examining the earthquake’s impact on plant buildings / structures that are deemed important in terms of anti-quake(Chairman)

the University of(Subcommittee)<WG on plant structures>
1st meeting: September 13
2nd meeting: October 23
3rd meeting: November 27
4th meeting: December 25<Joint WG on earthquakes, tsunami,(1)Examining the research data of relevant organizations on this earthquake to identify which undersea active faults should geology and subgrade>
1st meeting: October 12
be reflected in defining the level of an earthquake that forms the basis of anti-quake designs(2)Examining the observation data of seismic motions in this earthquake, and findings on the investigation into why theobservation data exceeded the design-basis figures at the foundations of reactor buildings at the power station, so as to
identify issues that should be reflected in defining the design-basis seismic motion(3)Examining the analysis results of seismic data observed at plant buildings in this earthquake, to identify issues thatshould be reflected to anti-quake safety assessment of buildings, structures, equipment and piping that are deemed
important in terms of anti-quake safety(4)Examining the findings of the study into the earthquake’s impact on facilities deemed important in terms of anti-quake
safety at the Kashiwazaki-Kariwa Nuclear Power Station, to identify issues that should be reflected to theimprovement of anti-quake performance for plant facilities(5)Examining the findings of the impact study on other facilities, to identify issues that should be reflected to the anti-quake
performance of plant facilities

2nd meeting: December 5
3rd meeting: December 25

(6)Summarizing the anticipated level of earthquakes and seismic motions that should be reflected to future anti-quake
safety assessment at the Kashiwazaki-Kariwa Nuclear Power Station, anti-quake safety assessment and anti-quake
performance improvement measures for the power station’s facilities that are important in nuclear safety, and issues
associated with anti-quake performance improvement for other facilities
4.Summarizing the insight obtained from this earthquake and examining issues to be reflected to other nuclear power stations from the perspective ofanti-quake safety assurance for nuclear facilities
Working Group on 1.Operation management (1)Assessing the operation management measures the utility implemented immediately after the earthquake, identifying
nuclearplant
administration andassessmentof

immediately after an tasks that should be addressed, and reflecting the knowledge to manuals as required
earthquake
a.Confirming the status of automatic shutdown (status of first scram, neutron flux fluctuations, and the operation /standby state of safety systems)(WG)
1st meeting: September 4
2nd meeting: October 2
3rd meeting: November 1

facility integrityb.Confirming the relevance of operation proceduresc.Examining the operation management that led to the iodine detection in the exhaust stack at Unit 7

4th meeting: December 1(Project Manager)

d.Examining non-conformity management regarding the release of leaked water at Unit 6<Sub-WG>

Professor
Sekimura,

Naoto 2.Assessment of facility (1)Grasping the status of plant facilities, examining what inspections are needed, and assessing the plant operator’s facility
integrity
inspection plan and its outcome
Graduate School of(2)Examining the method for assessing facility integrity, and exploring judging criteria on the need for repair work
Engineering,(3)Examining the results of inspections and assessment, to explore the method for repair work
University of Tokyo(4)Identifying items that should be reflected to guidelines and criteria to be applied in individual stages of assessment

1st meeting: November 12
2nd meeting: November 27