Report on the impact of the Niigata-Chuetsu-Oki Earthquake on the Kashiwazaki-Kariwa Nuclear Power Station
and response by Tokyo Electric Power Company (TEPCO), national and local governments and other bodies (Progress in August 2007)
Date

Wednesday
August 1

TEPCO and other power utilities and JANTI (Japan Nuclear Technology Institute)

National and local government

TEPCO press conference: Earthquake update (as at 3:00 p.m.)
NISA press release: Earthquake update (12th report)• In new developments, water was discovered in the cable trench (unrestricted area) running between the B1 level of the No. 6 reactor• Information received from TEPCO (as per column on left)
3
building (unrestricted area) and the B2 level of the control building (unrestricted area). The volume of water is estimated at 3 m , and• Safety inspectors are currently investigating the causes and other details at the plants based on TEPCO findings
no radioactive matter was detected.
• There are no significant changes in the main exhaust stack radiation monitor and monitoring posts at present• In light of the thin oil films detected on the No. 1 turbine building sub-drain and the discharge outlets for the Nos. 1- 4 reactors, aLocal government site examinations (through to August 2)
temporary oil separator tank was set up on July 31, together with oil-proof fencing with absorbent mats around the discharge outlets
On-site examinations were conducted in accordance with Article 10 of the Safety Agreement to check the extent
and, as an extra precaution, oil-proof fencing around the afterbay on the Arahama side (Nos. 1 – 4) and the Ominata side (Nos. 5 – 7).
of damage and confirm current safety conditions at the plant. The examination team was accompanied by the• All plants are shut down and stable at present. There are no significant changes in real-time data for the main exhaust stack radiation
Technology Committee for Safety Management at the Niigata Prefecture Nuclear Power Plant.
monitor and monitoring posts. There is no radiation impact on the surrounding environment.
<Inspection by> Niigata prefecture; City of Kashiwazaki; City of Kariwa; Technology Committee (August 1:
TEPCO press conference: Non-conformities update (as at July 26)
Eight persons under Chairman Miya; August 2: Seven persons under Chairman Miya)
Non-conformities report for Kashiwazaki-Kariwa nuclear power station (as at July 26) posted on website<Details> Examination and confirmation of extent of damage and current safety conditions at the plant, based on
the opinions and advice of the Technology Committee
Incidents<Other>Press
conference held on August 2 at the completion of the inspection
Total
attributable
Grade
Description
Comments
incidents toearthquake
Reportable incident under legislation/safety agreements• Water on operating floor
As
Incident with major impact on plant safety and/or
10
10• Transformer fire in theperformance
Unit No. 3
Serious non-conformity in relation to quality assurance• Misaligned connecting
criteria
ducts on main exhaust stackA
34
33
Incident with major impact on regular inspection• Damaged fire protection
processes
pipingNon-conformity identified by the competent authorities
B
25
21• Loose blowout panel
Incident necessitating stricter operational monitoring
Minor non-conformity in relation to quality assurance
C
527
491
criteria
Incident that can be corrected during normal maintenance
D
927
706
procedures
N/A
Replacement of expendables or equivalent
4(2)
Figures in brackets takenfrom newspaper reports
Total
1527
(1263)
Note by JANTIThe majority of the 70 or so incidents described in press releases to date are between As and B grades. The incidents describedhere are C grade and below and are related to normal ongoing operation i.e., part of regular non-conformity reporting.

TEPCO press release: Earthquake update (as at 2:00 p.m.)
Thursdaysday• No new developments or updates.
August 2• All plants are shut down and stable at present. There are no significant changes in real-time data for the main exhaust stack radiation
monitor and monitoring posts. There is no radiation impact on the surrounding environment.

NISA press release: Earthquake update (13th report)• Information received from TEPCO (as per column on left)• Safety inspectors are currently investigating the causes and other details at the plants based on TEPCO findings• There are no significant changes in the main exhaust stack radiation monitor and monitoring posts at present
NISA press release: IAEA inspection team visit to Kashiwazaki-Kariwa Nuclear Power Plant
A request was received on July 19 from the IAEA regarding the dispatch of an examination team in the name ofinternational cooperation to inspect the Kashiwazaki-Kariwa nuclear power plant and assess the impact of the
Niigata-ken Chuetsu-Oki earthquake. NISA announced that the team would be accepted on July 20 and 23. After
further negotiation, the IAEA has provided the following details of the examination team
1) Dates
August 6 – 10, 2007
• August 6 – 9: Inspect Kashiwazaki-Kariwa nuclear power plant, interview key officials• August 10: Hold discussions with NISA and other agencies
2) Location
TEPCO Kashiwazaki-Kariwa Nuclear Power Plant and Tokyo3) Team
Five-member team headed by IAEA nuclear safety commissioner Phillip Jamet, Director of the Nuclear
Installation Safety Division
4) Objectives
The objectives appear to be: to inspect the facility and interview key officials regarding radioactive leakage
and safety operational management, particularly with respect to earthquake protection; to establish the facts
and circumstances and identify the key outcomes; and to compile an official IAEA report on the situation.
Nuclear Safety Commission Meeting• Impact on nuclear power plant• Findings from analysis of seismic observation data at Kashiwazaki-Kariwa Nuclear Power Plant
generated during the Niigata Chuetsu offshore earthquake

FridayAugust 3

MondayAugust 6

TEPCO press release: Earthquake update (as at 2:00 p.m.)<New developments>• C shoe (red shoe) discovered on the bulkhead in the reactor well on the No. 1 reactor building operating floor. It was dislodged by
the earthquake from its position near the well opening and fell into the well. It will be recovered. (Non-conformity classification
changed from C to B grade on August 3.)• Lighting fixtures and ceiling panels fell to the floor in the No. 6/7 central control room; cracks appeared; emergency lights were
shifted out of alignment; and inspection apertures were left open. (Non-conformity classification changed from C to B grade on
August 3.)<Changes>• There was damage in two locations to joints on the drive shaft of the ceiling crane in the No. 6 reactor building. A subsequent
inspection of two other locations identified damage in one new location. Other sections will be checked thoroughly.
• A thorough investigation of oil retaining walls in the transformers of the Nos. 1 – 3 reactors found fissures and cracking in thebottom surface of the retaining walls. The soil directly underneath the retaining walls and in the vicinity is thought to becontaminated with insulating oil and may need to be removed.
All plants are shut down and stable at present. There are no significant changes in real-time data for the main exhaust stack radiation
monitor and monitoring posts. There is no radiation impact on the surrounding environment.

NISA press release: Earthquake update (14th report)• Information received from TEPCO (as per column on left)• Safety inspectors are currently investigating the causes and other details at the plants based on TEPCO findings• No significant changes in the main exhaust stack radiation monitor and monitoring posts at present
Minister of Economy, Trade and Industry Akira Amari: press conference following Cabinet meeting• In the event of any incident or phenomenon at any nuclear reactor in any country, information should be sharedwith all other nuclear power producing nations to enable prompt action to be taken. A database should becompiled so that such information can be shared throughout the world.
• The IAEA has stressed the importance and significance of the examination of the Kashiwazaki-Kariwa Nuclear
Power Plant and of information sharing. This is highly valid in this context. All nuclear power producing
nations should treat this incident as if it were their own.
• The examination process and information sharing will be conducted by the IAEA working in conjunction withlocal authorities. All comments and recommendations will be reported in full in Japan.
• We are attempting to correct misinformation, but we are inevitably perceived as biased towards the Japaneseperspective. As a result, the impact of the earthquake is not being reported accurately in the domestic media,
nor overseas. The IAEA represents a neutral third party so it is in our interests to have them deliver a balanced
assessment of the situation that will encourage accurate reporting. For this reason we believe the IAEA
examination is important and necessary.
• We will ask for the IAEA report to be compiled as quickly as possible.

TEPCO press release: Earthquake update (as at 2:00 p.m.)
NISA press release: Earthquake update (15th report)<New developments>• Information received from TEPCO (as per column on left)• Approximately 24 liters of oil has leaked from a stud bolt fastener on the Level 4 operating floor of the No. 6 reactor building. The• Safety inspectors are currently investigating the causes and other details at the plants based on TEPCO findings
leaking has now stopped, and the oil is being wiped up and disposed of.
• No significant changes in the main exhaust stack radiation monitor and monitoring posts at present• Workers in restricted areas at time of earthquake: Total 817 418 at No. 1 reactor, six at No. 2, 26 at No. 3, one at No. 4, 94 at No. 5, Nuclear Safety Commission Meeting
270 at No. 6 and two at No. 7. There were 52 workers on the operating floors of reactor buildings, involved in tasks such as• Non-conformities at nuclear power station caused by earthquake
checking ceiling cranes, preparing control rods for inspection, and performing decontamination procedures. Water from the spent• Impact on nuclear power stationfuel pool splashed onto a number of workers, but checks showed no radioactive material, and they were allowed to leave the• Site examination by Chairman Suzuki and visits to local government bodies
restricted area.
IAEA examination (1st day)All plants are shut down and stable at present. There are no significant changes in real-time data for the main exhaust stack radiation
monitor and monitoring posts. There is no radiation impact on the surrounding environment.
TEPCO press release: Announcement Release of digital seismic monitoring data from the Kashiwazaki-Kariwa Nuclear Power
Plant during the 2007 Niigata-ken Chuetsu-Oki earthquake
Digital observation records contained in the report presented to NISA on July 30 have been presented at no cost to the Association for
Earthquake Disaster Prevention for the purpose of academic investigation in seismology, seismic engineering and seismic technology.
<Details of records provided>
1) Data: Digital data on acceleration-time history waveforms for 33 seismographs where such data was available in the earthquake
2) Provided to: Association for Earthquake Disaster Prevention<For reference> from the Association for Earthquake Disaster Prevention website
Regarding observation records provided by TEPCO from the Kashiwazaki-Kariwa Nuclear Power Plant during the 2007 Niigata
Chuetsu-Oki earthquake• TEPCO notified the Association of its willingness to provide seismic monitoring records for the Niigata Chuetsu-Oki earthquake
as part of the process of repairing and restoring equipment and ascertaining safety levels at the Kashiwazaki-Kariwa NuclearPower Station• The data, taken close to the epicenter of the earthquake, is highly valuable for academic investigation in the fields of seismology,
seismic engineering and seismic technology. For this reason, the Association has decided to make the data available on
CD-ROM.
• For applications and inquiries contact: +81-3-3457-7453, FAX: +81-3-3457-7076, email: office@aedp-jp.com

Tuesday
August 7

TEPCO press release: Earthquake update (as at 2:00 p.m.)
New developments• Approximately 200 liters of hydraulic oil has leaked from a stud bolt tensioner* on the Level 3 operating floor of the No. 4 reactor
building. The leaking has now stopped, and the oil is being wiped up and disposed of.
* A hydraulic mechanism used to tighten the bolts that hold down the reactor pressure cover

IAEA examination (2nd day)
Nuclear Safety Commission —Statement from Chairperson Atsuyuki Suzuki: Site inspection and meetings
with local government authorities
The study team confirmed the latest information regarding the impact of the Niigata Chuetsu offshore
earthquake on the nuclear plant, and held discussions with local government authorities (the Niigata Prefectural
Government, Kashiwazaki City Offices, Kariwa Town Offices).

All plants are shut down and stable at present. There are no significant changes in real-time data for the main exhaust stack radiation NISA press release: Earthquake update (16th report)monitor and monitoring posts. There is no radiation impact on the surrounding environment.
• Information received from TEPCO (as per column on left)• Safety inspectors are currently investigating the causes and other details at the plants based on TEPCO findings• No significant changes in the main exhaust stack radiation monitor and monitoring posts at present

Wednesday
August 8

ThursdayAugust 9

FridayAugust 10

TEPCO press release: Earthquake update (as at 2:00 p.m.)• No new developments or updates.
• All plants are shut down and stable at present. There are no significant changes in real-time data for the main exhaust stack radiation
monitor and monitoring posts. There is no radiation impact on the surrounding environment.

IAEA examination (3rd day)TEPCO press release: Earthquake update (as at 2:00 p.m.)• No new developments or updates.
• All plants are shut down and stable at present. There are no significant changes in real-time data for the main exhaust stack radiation
monitor and monitoring posts. There is no radiation impact on the surrounding environment.

IAEA investigation (4th day)NISA press release: Earthquake update (17th report)• Information received from TEPCO (as per column on left)• Safety inspectors are currently investigating the causes and other details at the plants based on TEPCO findings• No significant changes in the main exhaust stack radiation monitor and monitoring posts at present
NISA press release: Earthquake update (18th report)• Information received from TEPCO (as per column on left)• Safety inspectors are currently investigating the causes and other details at the plants based on TEPCO findings• No significant changes in the main exhaust stack radiation monitor and monitoring posts at present
Nuclear Safety Commission meeting• Report on site inspection and visits to local authorities by Chairman Suzuki.
• Proposed scope of study of the impact of the Chuetsu offshore earthquake on the nuclear facility and associatedcountermeasures

TEPCO press release: Submission of accident and failure report and electrical damage report in relation to the impact of the IAEA investigation (5th and final day)Niigata Chuetsu-Oki earthquake on the Kashiwazaki-Kariwa nuclear power Station
Minister of Economy, Trade and Industry Akira Amari: press conference following Cabinet meeting
・ Following on from the report dated July 25, key data on plant operation at the time of the earthquake (listed below) was submitted• A new Fire Preparedness and Responses Office will be set up at NISA by the end of the month, with a manager
to METI.
and a staff of around five. Since the new unit will liaise directly with the Fire and Disaster Management<Data submitted to METI>
Agency, the manager will be appointed from the Fire and Disaster Management Agency of the Ministry of
1. Computer printouts
6. Reactor water temperatures
Internal Affairs and Communications.
2. Position of control rods
7. Exhaust stack radiation monitors• The Fire Preparedness and Response Office will work closely with the Fire and Disaster Management Agency
3. Neutron flux density
8. Core flow rate
to develop effective fire protection strategies and fire response procedures for nuclear power stations as
4. Reactor pressure
9. Main steam flow/supply water flow
quickly as practicable. These will be forwarded to electric power companies.
5. Reactor water level
NISA press release: Earthquake update (19th report)• The three key functions in terms of reactor safety stop, cool, shut off were all executed correctly. After the earthquake the reactors• Information received from TEPCO (see column on left)
remained in a stable state at low temperature.
• The Working Group on Management Procedures and Equipment Operation within the Committee for Studying• We will continue conducting investigations and submitting reports as necessary. We will also investigate the causes of the incidents
the Impact of the Chuetsu Offshore Earthquake on the Nuclear Power Plant will conduct an in-depth
described in the July 25 report and take appropriate action to prevent a recurrence, and submit a report on same to METI.
investigation into operations directly after the earthquake in light of the reported parameters indicating
TEPCO press release: Earthquake update (as at 2:00 p.m.)conditions at the plant at the time of the earthquake<New developments>• NISA will examine strategies developed by TEPCO to prevent recurrence of other reported nonconformities.
• The number of operators working on the operating floor of the reactor building at the time of the earthquake has been revised to• Safety inspectors are currently investigating the causes and other details at the plants based on TEPCO findings
65, an increase of 13. The 13 additional operators were conducting scheduled inspection tasks and inspecting fuel rod exchangers• No significant changes in the main exhaust stack radiation monitor and monitoring posts at present
at the time of the earthquake. None were affected by water splashes from the spent fuel pool.
• After the earthquake there was only one exit monitor still working at the Nos. 1 and 2 reactors. To ensure operator safety, TEPCO
ordered the operators (approximately 400) to leave the restricted areas without using the exit monitor, after confirming that there
were no operators wearing C type clothing for contaminated areas. This is classified as an emergency procedure.
All plants are shut down and stable at present. There are no significant changes in real-time data for the main exhaust stack radiation
monitor and monitoring posts. There is no radiation impact on the surrounding environment.

Nuclear Safety Commission: FY2006 White Paper on Nuclear Power
A summary was prepared on amendments to the 2006 licensing safety review regarding seismic safety standards.
• The summary of amendments to the licensing safety review regarding seismic safety standards provides anoverall description seismic protection strategies using simplified language, divided into three sections asfollows:
1. Basic principles of seismic safety for nuclear power plants and role of seismic safety guidelines
2. History of seismic safety guidelines; details of amendments and new guidelines
3. New initiatives introduced with the amendments, such as back checking, and future issues
Press conference by Niigata Prefectural Government: 4th radiation measurement in farming and marine
produce
The Niigata Prefecture Radiation Monitoring Centre and the Kashiwazaki-Kariwa Radiation Monitoring Center(also located in Niigata prefecture) conducted radiation testing farm produce sourced within a radius ofapproximately 10 km of Kashiwazaki-Kariwa nuclear power plant and marine produce sourced within a radius ofapproximately 20 km.
• Radiation was not detected in any of the produce tested. This is consistent with the results of previous radiation
tests released on July 21, 26 and 27.

MondayAugust 13
Tuesday
August 14
Wednesday
August 15
ThursdayAugust 16

Nuclear Safety Commission• Impact on nuclear power plant
JANTI: Kashiwazaki-Kariwa Nuclear Power Plant on-site investigation by four-member teamTEPCO press release: nonconformities in post-earthquake inspection and restoration program
NISA press release: Earthquake update (20th report)
Notification of nonconformities (for discussion) in the period August 1 – 8 2007 based on the document “Update Announcement• Information received from TEPCO (as per column on left)
Regarding Nonconformities in Inspection and Restoration Program in the Aftermath of the Niigata Chuetsu-Oki earthquake”• TEPCO will roll out an inspection program extending to the reactor bases, starting with an inspection of the top<Nonconformity information (Chuetsu offshore earthquake: As – not included) >of the No. 1 reactor pressure vessel scheduled for August 21, and will also release video material as
appropriate. NISA will check for instances of damage and significant deformation.
August 1 – 8, 2007 (cumulative total since July 16, 2007)• Inspection of the No. 7 reactor pressure vessel will begin in October. As with the No. 1 reactor, NISA will
Items
470 (1,948)
check for instances of damage and significant deformation.
• NISA inspectors are conducting an in-depth investigation into the causes of plant issues identified by TEPCO• No significant developments in the main exhaust stack radiation monitor and monitoring posts

FridayAugust 17

SaturdayAugust 18
SundayAugust 19

TEPCO press release: Geological surveys of TEPCO nuclear power plant in light of the Niigata Chuetsu-Oki earthquake• In light of the recent earthquake, TEPCO conducted a geological survey involving marine sonic profiling of the sea area in thevicinity of the facility. The survey will include the range of aftershocks. (Announcement made July 26, 2007).
• Following the in-depth investigation, it was subsequently decided to Augustment the marine sonic profiling by widening the scope ofthe geological survey to include sub-ground exploration of the land area surrounding the Kashiwazaki-Kariwa nuclear power plant(this had in fact been underway since the previous year as part of a seismic safety evaluation). Sub-ground exploration willconcentrate on the land area including the Nagaoka Hirano Nishi Midori fault zone, and will evaluate the underground structure,including assessment of active fault lines.
• Meanwhile, boring studies of the site area will be used to assess the underground structure to considerable depth. Ground and rocksamples will be analyzed to assess subsidence and/or liquefaction of the ground as a result of the earthquake.
• Geological surveys of surrounding land and sea areas will be conducted at the Fukushima Nos. 1 and 2 nuclear power plants in lightof the recent earthquake, in order to Augustment and supplement previous surveys.
IAEA
Report of the IAEA study group released (conclusions section)

Monday
August 20

NISA press release: Release of the Conclusions section of the report of the IAEA mission on the impact on
the Kashiwazaki-Kariwa nuclear power plant• On August 18, the International Atomic Energy Agency (IAEA) released a report on investigations conducted
August 6 – 10.
• NISA welcomes the thorough and professional investigation by IAEA and the prompt release of the reportfollowing the conclusion of the investigation• In particular, the IAEA has vindicated our initial position regarding groundless rumors on the impact of theearthquake being put forward by local governments in the area, by adjudging the risk of radiation exposure due
to leakage of radioactive material as being well below the prescribed limits.
• NISA will examine the report in detail and incorporate its findings into future initiatives, including
deliberations by the Chuetsu-Oki Earthquake Study and Response Committee.
<Study of the report of the IAEA Study Group>
1) Reactors operating at the time of the earthquake shut down automatically without incident. All reactors were
safe both during and after the earthquake. The three fundamental safety functions — “reactivity control”,“removal of heat from the core”, “confinement of radioactive materials” — functioned properly.
2) There was very minor radioactive releases which occurred shortly after the earthquake; however this was well
below the authorized limits for radioactive exposure.
3) Safety structures, systems and equipment all withstood the earthquake extremely well — better than expectedin fact, given the magnitude of the earthquake — with no signs of visible damage. This can be attributed to thegenerous safety margins built in at various stages of the design process.
4) A secondary evaluation must be performed in line with the new seismic design guidelines to assess the impactof the earthquake and determine the likelihood of an active fault beneath the power plant.
5) While all equipment appears to be functioning properly during normal operation, the potential for hidden
damage should also be taken into consideration
Electric Power Companies: Modifications to seismic design safety evaluation programs for nuclear power plants
The power companies have been evaluating seismic design safety under Seismic Design Safety Evaluation Programs submitted
on October 18 2006 in accordance with a NISA directive accompanying amendments to the Seismic Design Review Guidelines
for Nuclear Power Plants.
The Program was revised in accordance with a written directive* from the Ministry of Economy, Trade and Industry received on
July 20, 2007, in light of the Niigata Chuetsu-Oki earthquake, and resubmitted to the Ministry today.
* 3. Seismic design predicated on public safety• Knowledge gained through the Niigata Chuetsu-Oki earthquake should be incorporated into seismic safety evaluation• Investigate the potential for modifying Programs to ensure proper implementation in accordance with progress of current
evaluations and to promote earliest possible completion; report back within one month with conclusions<Example from TEPCO press release>
The main modifications are as follows:• In light of the Niigata Chuetsu-Oki earthquake, the scope of existing surveying will be expanded to include geological surveying.
• An overview of seismic design safety evaluation of leading nuclear power plants — the Fukushima No. 1 plant and the
Fukushima No. 2 plant — will be included in the intermediate report completed by the end of March 2008
• Seismic design safety at the Kashiwazaki-Kariwa nuclear power plant following the Niigata Chuetsu-Oki earthquake will beassessed, and an evaluation of seismic design safety under the new Guidelines will be conducted.
Given that seismic ground motion in excess of the Kashiwazaki-Kariwa nuclear power plant design specifications was recorded
during the Niigata Chuetsu-Oki earthquake, an independent study will be conducted to compare seismic records at the foundation
slabs of the reactor buildings in the Kashiwazaki-Kariwa nuclear power plant with the seismic ground motion data used in the designof the Fukushima No. 1 plant and the Fukushima No. 2 plant. The study will look at the impact on the three fundamental safetyfunctions of Stop, Cool down and Containment. It will report back within one month. It will be in addition to the seismic design
safety evaluation.

NISA press release: Reports from power companies regarding updating of seismic design safety evaluation(seismic back checking) programs• Following amendments to the seismic safety guidelines dated September 19 2006, the Ministry for the Economy,
Trade and Industry on September 20 2006 ordered power companies to submit implementation schedules aheadof seismic design safety evaluation (seismic back checking) of nuclear power plants (both operational and underconstruction) in line with the amended seismic safety guidelines.
• Implementation schedules were duly submitted by the power companies on October 18 2006
• Following the Niigata Chuetsu-Oki earthquake on July 16 2007, the Ministry instructed the power companies toinvestigate revisions to seismic back checking schedules• The power companies today reported on revisions to implementation schedules. The report is summarized below:
1) With the exception of the Kashiwazaki-Kariwa nuclear power plant and the Hamaoka nuclear power
plant (which has already submitted a report on seismic back checking), the power companies willcomplete geological surveying and associated preliminary ground movement strategies by the end of thecurrent fiscal year, as well as evaluation of key safety equipment and facilities at each plant.
2) In light of the earthquake, additional marine sonic profiling will be conducted at the seven power plants*
and the Rokkasho reprocessing plant. With the exception of the Hamaoka nuclear power plant (which has
already submitted a seismic back checking report and is being discussed by the seismic safety andstructural design sub-committee), all the power plants reported on today will conduct marine sonicprofiling in accordance with the amended guidelines.
* The seven power plants are Kashiwazaki-Kariwa, Fukushima No. 1, Fukushima No. 2, Shimane, Ikata,
Genkai and Tokai No. 2
3) Voluntary measures adopted by the power companies include seismic back checking as well as safety
analysis based on the level of seismic ground motion recorded in the foundation slabs of theKashiwazaki-Kariwa nuclear power plant, to be completed within one month.

Wednesday
August 22

TEPCO Press Release: Analysis of seismic observation data from the Kashiwazaki-Kariwa Nuclear Power Plant (2nd report)
NISA Press Release: Analysis of seismic observation data from the Kashiwazaki-Kariwa Nuclear Power• The first report on the analysis of seismic observation data from the main part of the Niigata Chuetsu offshore earthquake was
Plant (part 2)
presented to NISA on July 30 (notified on July 30 2007).
• Information received from TEPCO (see left-hand column)• Further investigations including analysis of seismic observation data from aftershocks were presented in the form of the second report• NISA will analyze the reports in consultation with experts in the field
to NISA today.
• In light of the loss of the main earthquake observation records for the No. 1 and No. 5 Units, the aftershock data will be used tosupplement the lost data.
• We will use the outcomes obtained thus far for the main earthquake and aftershocks to continue analyzing seismic observation records
and assessing seismic safety levels of key facilities.
• Observation data from the report has today been provided, free of charge, in digital form, to the Association for Earthquake Disaster
Prevention for use in seismology, seismic engineering and seismic technology studies.
TEPCO Press Release: Report of Damage to Reactor Facilities and Electrical Equipment at Kashiwazaki-Kariwa Nuclear Power NISA Press Release Earthquake update (21st report)
Plant caused by the Niigata Chuetsu offshore earthquake investigation into the fire in internal transformer 3B• TEPCO provided an update on issues identified during inspection and restoration work in the period 17 – 22
• A summary of the findings from our investigation into the fire in the internal transformer 3B in the No. 3 reactor that was caused byAugust 2007 as well as a schedule of future inspection and restoration work at the Kashiwazaki-Kariwa
the earthquake was presented to the Minister for Economy, Trade and Industry today as a follow-up to the Report in accordance with
Nuclear Power Plant, and reported that no damage, deformities or loose components were identified during
Article 19 (17) of the Installation and Operating Regulations for Nuclear Power Reactors and Article 3 of the Electrical Reporting
Phase 1 of the No. 1 reactor internal inspection at Kashiwazaki-Kariwa Nuclear Power Plant, conducted
Regulations submitted on August 10, 2007.
between 21 and 23 August.
• We will continue to investigate the impact of the earthquake on the power plant and submit further reports as necessary, while also
• Today a follow-up report was received from TEPCO to complement the mandatory accident and failure reports
investigating the causes of phenomena reported to date and working to prevent reoccurrence in the future and reporting thesesubmitted previously (received 25 July and 10 August). Today’s report provided new information about theprocesses to the Minister for Economy, Trade and Industry
causes of the fire in the No. 3 reactor internal transformer (B)<Possible chain of events>• NISA will investigate equipment and facility damage via a special four-week safety investigation starting 3
1) The earthquake caused subsidence in the foundations of the connecting bus wire duct on the transformer secondary side
September; this will include analysis of internal reactor equipment identified in today’s report. The Operation
2) The subsidence caused the duct connections to come loose; the duct then fell and came into contact with the connection
Management and Equipment Safety WG (part of the Chuetsu Offshore Earthquake Nuclear Power Plant
terminals
Investigation and Countermeasures Committee) will also conduct an in-depth investigation.
3) The duct damaged the bushings, causing oil to start leaking• Inspection of the reactor pressure vessels at the No. 7 reactor will commence during October. NISA will check4) The duct came into contact with the connection terminals, causing short-circuits (including ground faults) and sparks/arcing
for signs of damage and significant deformation, as per the No. 1 reactor
5) The sparks ignited the oil and started the fire
• Safety inspectors are currently in the process of an in-depth investigation to establish the causes of issues at the<Action taken>
Action will be taken on the basis of the investigation findings to prevent future recurrence of such incidents
plant identified by TEPCO• No significant developments in the main exhaust stack radiation monitor or monitoring posts at present• A thorough evaluation will be conducted into the cause of the fire at the No. 3 reactor internal transformer (B),and action will be taken to prevent a recurrence

ThursdayAugust 23

TEPCO Press Release: Nonconformities in post-earthquake inspection and restoration process (weekly report for 17 – 22 August)
Report of issues identified in the period 17 – 22 August 2007 and nonconformities (as per discussions) identified in the period 9 – 15
August 2007 as per the report Update on nonconformities identified in inspection and restoration work following the Niigata
Chuetsu-Oki earthquake
1. Issues related to the Chuetsu-Oki earthquake
17 – 22 August 2007
By category (cumulative total since 10 August 2007)(cumulative total since 10 August 2007)
No. ofissues

1
(1)

I

0 (0)

II
III

0 (0)
1 (1)

<17 – 22 August 2007>
Date
Category
Name
Description
identified
I
II
22
Cracks in oil retaining wall in No.
III
Cracks identified in foundations after laying gravel
August5 reactor
2. Nonconformities (related to Chuetsu-Oki earthquake: As excluded)
9 – 15 August 2007 (cumulative total since 16 July 2007)
No.
432 (2,380)
Elsewhere, no damage/deformation/dislodgement or other issues identified in No. 1 reactor internal inspection (Phase 1) conducted 21 –23 AugustTEPCO Press Release: cracking in transformer oil retaining wall in No. 5 Unit
• Cracks were identified in the foundations of the oil retaining wall of the transformer in the No. 5 reactor on 22 August, together withgaps in the jointing and caved-in section• Damage to oil retaining walls in the Nos. 1, 2 3, 4 and 7 reactors has already been notified• The only remaining reactor No. 6 will be checked by the end of August using gravel

FridayAugust 24

MondayAugust 27

ThursdayAugust 30

JANTI: Delegation visited NEI in the United States to introduce an update report and engage in discussion (4 members including
Dr. Ishikawa, President of JANTI)TEPCO website: Inspection of No. 1 reactor
WG on internal fire protection systems and incident reporting structures in relation to the Chuetsu-Oki• Visual inspection at the power plant following the earthquake found no problems with key equipment inside reactor vessels
earthquake• Regular inspection was being conducted at the time of the earthquake. The lid of the No. 1 reactor was open, and internal inspection wasin progress• The three-stage inspection process involves checking for internal damage or significant internal deformation and abnormalities in bolts,
brackets and other hardware that holds machinery in place. Lights and cameras are lowered into the reactor and the operators check thevideo display (process illustrated with video).
• The first stage inspection, conducted on 21 – 23 August 20007, found no evidence of damage, deformation or loose components.
NB: Stage 1: Upper section of reactor (21 – 23 August): completed
Stage 2: Middle section of reactor (mid to late September)Stage 3: Lower section of reactor (November – December)
TEPCO Press Release: Nonconformities identified in post-earthquake inspection and restoration process (Weekly report for 23 - NISA Press Conference: Earthquake update (22nd report)
30 August)• A progress report on inspection and restoration work at the Kashiwazaki-Kariwa Nuclear Power Plant
Notification of inspection and restoration process at Kashiwazaki-Kariwa Nuclear Power Station following the Niigata Chuetsu -Okifollowing the Niigata Chuetsu offshore earthquake during the period 26 August – 22 September was received
earthquake (from 26 August to 22 September 2007) including nonconformities
from TEPCO (see attached)
1. Inspection and restoration• Internal reactor inspection (Phase 2) at the No. 1 reactor is due to begin on 14 September; NISA will check for
Inspection/restoration completed between 24 and 30 August 2007
signs of damage and significant deformation• No. 1 reactor: main transformer: external visual inspection completed 29 August• Inspection of reactor pressure vessels in the No. 7 reactor is due to commence during October; NISA will check• No. 2 reactor turbine building ceiling crane inspection completed 24 August
for signs of damage and significant deformation, as per the No. 1 reactor
Inspections commencing during the period 31 August – 6 September 2007
• Safety inspectors are currently in the process of an in-depth investigation to establish the causes of issues at the• No. 2 reactor operating floor service tools
plant identified by TEPCO• No. 2 reactor internal transformer• No significant developments in the main air stack radiation monitor or monitoring posts at present• No. 3 reactor main transformer• No. 4 reactor turbine building ceiling crane• No. 5 reactor building ceiling crane
2. Nonconformities identified during inspection/restoration work following the Niigata Chuetsu offshore earthquake
inspection and restoration work following the Niigata Chuetsu offshore earthquake
Report of issues identified in the period 23 – 29 August 2007 and nonconformities (as per discussions) identified in the period 16 – 22
August 2007 as per the report Update on nonconformities identified in inspection and restoration work following the Niigata
Chuetsu-Oki earthquake
1) Issues related to the Chuetsu-Oki earthquake
23 – 29 August 2007
By category (cumulative total since 10 August 2007)(cumulative total since 10 August 2007)
No. ofissues<23- 29 August 2007>
Date
Category
identified
I
II
III
-

0
(1)

I

0 (0)

II
III

0 (0)
0 (1)

Name

Description--2) Nonconformities (related to Chuetsu offshore earthquake: As excluded)
16 – 22 August 2007 (cumulative total since 16 July 2007)
No.
175 (2,555)

Friday
August 31