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 July 2007)
Date

MondayJuly 16,2007

Tuesday 17
July

TEPCO and other power utilities and JANTI (Japan Nuclear Technology Institute)
10:13 approx. Earthquake occurs

National and local government

TEPCO press release: Earthquake update (as at 1 p.m.)• Kashiwazaki-Kariwa nuclear plant reactors 2, 3, 4 and 7 scrammed automatically. Reactors 1, 5 and 6 were already shut down for
periodical inspection.
• The fire department confirmed that a fire in the transformer of the No. 3 reactor was brought under control (12:10 p.m.)• There is no environmental impact from the earthquake and associated fire.
TEPCO press release: Earthquake update (as at 6:30 p.m.)• Several aftershocks were recorded but did not affect any sections of the plant• All sections were checked for Departure from Limiting Condition of Operation (LCO)- Reactors 1, 2 and 3: low water level in spent fuel pool (violation rectified)- Reactor 3: Reactor building blow-out panel removed (investigation of violation continuing)- Reactors 4, 5, 6 and 7: no violations
Seismic observation records at the plant (preliminary data)
Directives from Director of Nuclear and Industrial Safety Agency (NISA) to TEPCO: Analyze seismic• Recorded earthquake movement provisional values for foundation mat at lowest part of reactor building (with design acceleration observation data and determine impact on earthquake resistance
response at the same location shown in brackets), in gal
Directed to base the report on the fact that the maximum seismic acceleration recorded at Unit 1, 5 and 6
exceeded the maximum response acceleration based on the base level of seismic motion
Recorded
No. 1 reactor
No. 5 reactor
No. 6 reactor• Analyze seismic observation data from the earthquake
Horizontal (N-S)
311(274)277(249)271(263)• Check whether the earthquake has compromised safety of key equipment and facilities
Horizontal (E-W)
680(273)442(254)322(263)
Vertical408(235)
205(235)488(235)TEPCO press release: Leakage of radioactive matter from Unit 6• Confirmation of water leakage in uncontrolled areas on 3rd level and mid 3rd level of reactor chamber (12:50)• Confirmation of radiation in water (18:20)• Volume of water leak: 3rd level = 0.6 l, approx 2.8 x 102 Bq; mid 3rd level = 0.9 l, approx 1.6 x 104 Bq• The water then flowed out to the sea via a discharge outlet (approx. 1.2 m3, 6 x 104 Bq)• Water is no longer reaching the sea. No significant change in sea level monitor reading, which is below the legislated value

Directives from Director of NISA to power utilities: directives to power companies affected by fire andradiation leakDirections to power companies in receipt of directives from the METI Minister regarding unacceptable delays inlaunching fire-fighting response and in communicating the radiation leak to NISA at the Kashiwazaki-Kariwa
nuclear plant• Inspection and report on fire-fighting procedures for fires at the nuclear plant• Review and report on organization of communication structure between nuclear plant and head office andbetween head office and the relevant government authorities in regards to incidents such as radiation leaks
NISA press release: Leakage of radioactive material from Unit 6
NISA response to the report from TEPCO dated July 16 regarding radioactive leak from Unit 6• NISA inspectors confirmed that discharge of radioactive water had ceased, and vindicated TEPCO’s original
outlook• TEPCO was ordered to maintain a strict program of monitoring for leakage in the surrounding surveillancearea; to put in place a rigid reporting structure; and to identify and rectify the causes

TEPCO press release: iodine and other substances detected from main exhaust stack of Unit 7• At approximately 1:00 p.m., iodine and radioactive particulate matter (Cr-51, Co-60) were detected during regular observation of themain exhaust stack• Total radiation was 3 x 108 Bq, dosage was approximately 1.1 x 10-7 mSv, well below the legally prescribed maximum (1 mSv per
individual)• No significant changes in the main air stack radiation monitor or monitoring post
• Other exhaust stacks will be monitored
TEPCO press release: Earthquake update (as at 5:00 p.m.)
Unit 1: 8 incidents including: oil leak from exciter transformer (minimal, ongoing); water puddle under damaged fire-fighting pipes (1,670
m3 )Unit 2: 7 incidents including: oil leaking from flange under main transformer (ongoing)
Unit 3: 5 incidents including: fire in 3B house transformer (brought under control)
Unit 4: 3 incidents including: misaligned connecting ducts on main exhaust stack
Unit 5: 4 incidents including: water leaking from No. 4 filtrate water tank
Unit 6: 3 incidents including: oil leak from low-start transformer B (minimal, ongoing)
Unit 7: 3 incidents including: cracks in joints of reinforcement along inlet channel embankment (up to 8 cm in size)
Switch yard: 3 incidents including: 500 kV New Niigata 2L shut down
Solid waste storage warehouse: Around 100 drums toppled (some with lids open)
Administration office building: 2 incidents including: normal power supplies shut down
Site/other: Seven incidents including: damage to fire-fighting equipment in four locations; water leaks

NISA press release: Iodine detected in main air stack of Unit 7• Information received from TEPCO (see left)• Cause unknown. Potential causal relationship with earthquake unclear. NISA to launch full investigation

NISA press release: earthquake update• Information received from TEPCO (see left)• Council member Kato has today dispatched four more NISA officials to work alongside the inspectors at thesite• TEPCO findings that iodine detected in the main exhaust stack of the Unit 7 has no impact on the surrounding
environment were accepted• All values detected at the main exhaust stacks of Unit 1 through 6 were below the minimum requirements• Instructed to immediately assess the situation with toppled solid waste drums

TEPCO press release: Amendment to notification of radiation leak from Unit 6 (dated 16 July)• Discharge out to sea: Amended from 6 x 104 Bq to 9 x 104 Bq

NISA press release: Radiation leak from Unit 6• Information received from TEPCO as per amendment• TEPCO still maintains that the three-month radioactivity concentration in the surrounding surveillance area isless than 2 in 10 billion Bq/cm3, due to dilution of radioactive matter. This figure is a billion times less than the
maximum allowable discharge concentration in the surrounding surveillance area over three months (0.2
Bq/cm3).
• The error in the announcement on the 16th was extremely regrettable• A full investigation will be conducted into the source of the calculation error. Faster and more rigorous
reporting was ordered.
WednesdayNISA press release: Earthquake update
18 July• Information received from TEPCO (see left)
TEPCO press release: Earthquake update (as at 5:00 p.m.)
Unit 1 = 9 incidents, Unit 2 = 9 incidents, Unit 3 = 8 incidents, unit 4 = 4 incidents, Unit 5 = 4 incidents, Unit 6 = 3 incidents, Unit 7 =• Investigations by Mr. Kato and inspectors at the plant are continuing
5 incidents, Switch yard = 3 incidents, Solid waste storage warehouse = 1 issue, Administration office building = 2 incidents,• Confirmation that radioactive water did not leak from toppled drums
Site/others = 9 incidents• As yet, no significant directives confirmed for main air stack radiation monitor and monitoring posts• Observations of the concentration of radioactive matter in the air in the solid waste storage warehouse were taken at four locations. No
radioactive matter was detected. Approximately 16 l of water had leaked from the toppled drums, but no radiation was detected.
Inspection is continuing
Mayor of Kashiwazaki, Hiroshi Aida
• Issued direction of emergency prohibition of use of some facilities for all Units at the plant (in relation todangerous facilities such as outdoor tanks), in accordance with the Fire Services Law
TEPCO press release: Seismic observation records at K-K NPS (subsequent to preliminary data released 16 July)
Nuclear Safety Commission• Data for the earthquake has been collected from all Units
1) Findings from site investigation• Seismic acceleration observations measured at foundation mat at lowest part of reactor building (with design acceleration response at2) Impact on the nuclear power station
the same location shown in brackets), in gal
3) Outbreak of fire in the transformer at Unit 3 and subsequent response<Findings from site investigation>a. Investigation conducted by three officials, including acting Chairman Higashi and Mr. Hayata
Recorded
Unit 1
Unit 2
Unit 3
Unit 4
Unit 5
Unit 6
Unit 7b. Sites visited: Unit 3 house transformer (fire outbreak), Unit 2 transformer (damage to foundation bolts), No.
Horizontal
311(274)304(167)308(192)
310(193)277(249)271(263)267(263)
6 reactor exhaust stack area (water leak), control room for Unit. 6 and 7, solid waste storage warehouse(N-S)
c.
Observations
from Mr. Higashi:
Horizontal
680(273)606(167)384(193)492(194)442(254)322(263)356(263)• The No. 7 reactor scram automatically at the time of the earthquake. A readout in the central control room of(E-W)
indicated that the reactor is under cold shutdown. Operators will need to continue checking the reactor core.
Thursday 19
Vertical408(235)282(235)
311(235)
337(235)
205(235)488(235)355(235)• The response to the fire in the transformer at Unit 3 at the time of the earthquake constitutes a key issue. It is
July
important that the lessons learned from this incident are passed on to other power stations.
• Water containing trace levels of radiation spilled from the spent fuel pool of the No. 6 reactor due to major
tremors during the earthquake, and also because containment did not function adequately. We were told thatit may have reached the uncontrolled area
<Statement from Chairperson Atsuyuki Suzuki>• The power plant is essentially safe. It did not reach a serious state. All operating reactors scramed
automatically as they were designed to do, and the key safety features providing multiple layers ofprotection from highly radioactive material inside the reactor functioned properly. Nevertheless, theearthquake has had a significant impact on the plant, as exemplified by the transformer fire.
• The radioactive water leak into the uncontrolled area will be investigated based on reports from operators andgovernment authorities as well as the findings of the Nuclear Safety Commission.
TEPCO press release: plant status (as at 5:00 p.m.)• According to the Nuclear Safety Commission findings, there are many lessons learned from the transformer
All facilities have been inspected externally where possible. The results are as follows:
fire, with respect to procedures at other nuclear plants and fire-fighting techniques in general. The necessary• Reactors 2, 3, 4 and 7 shut down automatically and are now stable in cold shutdown
studies should be carried out as soon as practicable in order to identify the salient issues.
• Two incidents involving radioactivity emission• We have put in a strong request to the government authorities to instruct the operators to evaluate the impact
1) Water leak from Unit 6 discharged into the open seas (July 16 press release)of the earthquake on the seismic resistance of the plant. The operators will also be asked to perform- Level of radiation discharged into the sea was approximately 9 x 104 Bq; total radiation exposure was approximately 2 x 10-9
additional studies to identify the location of the fault line.
mSv (well below the legally prescribed maximum of 1 mSv per individual per year)• We will lobby the operators and the government authorities for a thorough investigation in line with the- The SF pool water that flooded into the operating floor of the reactor chamber (a controlled area) is thought to have made its
newly amended guidelines with respect to the suitability of the original design and the emergence of new
way into the uncontrolled area along the fuel exchanger cables and wire ducts. The cause is still under investigation.
knowledge which was not available at the time.
2) Iodine and radioactive particulate matter detected in main exhaust stack monitor of No. 7 reactor (July 17 press release)•Webelieve that the back check will demonstrate the validity of the new guidelines for the recent earthquake.
- Radiation level detected thus far from the main air stack is approximately 4 x 108 Bq; total radiation exposure wasNow
is not the time to debate the pros and cons of further amendments to the new guidelines. The validity
approximately 2 x 10-7 mSv (well below the legally prescribed maximum of 1 mSv per individual per a year)
depends on whether the requirements are adequate. We must not make any assumptions.
- Evaluation of radiation levels continuing
NISA press release: Earthquake update• Main findings identified thus far:
• Information received from TEPCO (see left)- 14 incidents involving radioactive matter: the 2 incidents described above, misaligned connecting ducts on main exhaust stack• Mr. Kato and inspectors at the plant reported no problems with reactor vessels and associated equipment and3(Unit 1 through 5), water puddle under damaged fire-fighting pipes (1,670 m ) (Unit 1), water on operating floor in reactor
machinery based on visual inspectionbuilding (Unit 1 through 6)• As yet, no significant directives confirmed for main air stack radiation monitor and monitoring posts- 53 incidents not involving radioactive matter

TEPCO press release: Update on investigation into iodine detected in main exhaust stack of Unit 7<Origin of iodine discharge into the environment>• Delay to shut off turbine ground exhaust ventilator after automatic reactor scram• As a result, residual iodine and radioactive particulate matter in the condenser was sucked into the exhaust ventilator and discharged
via the exhaust stack. The investigation is continuing.
• Analysis of reactor water samples indicates that there was no leakage of radioactive matter from the fuel rods into the reactor water<Environmental impact>• The monitoring frequency for radioactive iodine and particulate matter in the main exhaust stack has been increased from once per
week to daily. Atmospheric monitoring in the surrounding surveillance area is also being conducted daily as of July 18 onwards.
• Iodine 131 and iodine 133 were detected in the main exhaust stack on July 18, but were not detected in the surrounding surveillancearea on July 18 or 19.
• The total radiation dose from the main air stack thus far is approximately 2 x 10-7 mSv

NISA press release: iodine detected in main exhaust stack of Unit 7 (the second report)• Information received from TEPCO (see left)• NISA officers are currently confirming iodine emissions from air stack and reactor water measurements• TEPCO to be instructed to take necessary actions with respect to emission controls
NISA press release: investigation of damages
Mr. Kato and three other officers were dispatched to the plant to conduct an investigation together with NISA
inspectors. Their findings are as follows:
1) Outbreak of fire in the Unit 3 and containment thereof• The initial response to the fire was inadequate, primarily because those on duty were too busy to provide
the required notification of the reactor scram, and also they did not have a proper understanding of theextent of the fire
• NISA will advise on developing better initial response procedures
2) Radioactivity leakage from the Unit 6• Radioactive material leaked from a terminal box in the mid 3rd level ceiling of the uncontrolled area
directly below the operating floor, and traveled through the mid 3rd level and via the 3rd level floor drain
to the non-radioactive storm drain sump (NSD), from where it was pumped out to sea.
• For the moment, leakage from mid 3rd level is being collected in a container, and the pump at the NSD has
been reconfigured to prevent it starting up automatically.
• The delay in reporting can be attributed to two main factors: the lack of a proper structure dictatingprocedures required of the radiation monitoring officer immediately after an earthquake, from samplingthrough to radiation monitoring; and the prevailing mindset among the operators that leakage in theuncontrolled area could not possibly be radioactive, which lead them to distrust the initial radioactivity
readings and recheck the measurements repeatedly.
• NISA has instructed TEPCO to continue with investigations in order to identify the route taken by theleaked material. NISA will also advise TEPCO as necessary based on the findings of the investigation andassociated preventative measures.

Friday July
20

TEPCO press release: Results of radiation readings from main exhaust stack of Unit 7
Environmental impact• Iodine 131 and iodine 133 were detected in the main air stack on July 18, but not on July 19.
• The total radiation dose from the main exhaust stack thus far is approximately 2 x 10-7 mSv (no change from July 19)• Monitoring for iodine and radioactive matters in the main exhaust stack will be conducted on a daily basis for the immediate future
TEPCO press release: Earthquake update (as at 1:00 p.m.)
63 issues confirmed to date (not including the four automatic reactor scrams at the time of the earthquake)1) Incidents related to radioactive materials (15 issues)- Discharge of water containing radioactive material out to sea (Unit 6)- Iodine and radioactive particulates detected at main exhaust stack monitor (Unit 7)- Misaligned connecting ducts on main exhaust stack (Unit 1 through 5)- Water puddle in combined reactor building from damaged fire-fighting pipes (1,670 m3) (Unit 1)- Water puddle on operating floor in reactor building (Unit 1 through 7)2) Incidents NOT related radioactive materials (52 issues, including the four automatic reactor scram at the time of the earthquake)3) Other damage and leakage caused by the earthquake• Confirmation of pool water splashing, leakage from the filtrate tank, misaligned ducts on main air shaft
and key safety equipment in storage vessels• Confirmation of seismograph location and acceleration amplitude records; found to be consistent withTEPCO statements• Confirmation from observation data that iodine was indeed detected in the main air shaft of the No. 7
reactor; unable to determine exactly when the iodine (and other materials) were released however• Confirmation from sample analysis that iodine was not detected in the Nos. 1 through 6 reactors during theweek of the earthquake• NISA will order an investigation into potential causal relationships with detection of iodine (and othermaterials) and the earthquakeNISA press release: Iodine detected in main exhaust of Unit 7 (the third report)• Information received from TEPCO (see left)• NISA officers at the plant are currently checking over data for iodine discharge from the air shaft and reactor
water measurements. NISA will continue to monitor the situation strictly
NISA press conference: Earthquake update (the fourth report)• Information received from TEPCO (see left)• NISA officers are currently at the plant:- The data demonstrates that there was no radiation in the collected water that was discovered on the 5th floor
below ground of the reactor combined building, which had come from damaged fire-fighting pipes in the
Unit 1.
- Observations data shows that iodine and particulates were not detected in the main exhaust stack of the Unit
7 on July 18 and 19.
- NISA officers are present at the TEPCO investigation into the route taken by the water leak in theuncontrolled area of the No. 6 reactor to determine whether TEPCO’s assumptions were correct• There are no significant changes in the main air stack radiation monitor and monitoring posts

TEPCO press conference: Investigation into fire in the house transformer 3B at Unit 3
Directive from METI minister to power utilities
Inspection involved mainly above-ground inspection and found the following:
Stipulates measures required in order to ensure the safety and security of the people. Details of planned• The connecting bus line section on secondary side of the transformer had slipped downwards relative to the transformer foundations
modifications/upgrades in accordance with 1) and 2) below must be submitted by July 26.
• The transformer and the connecting bus line on the secondary side are out of vertical alignment1) Upgrade to internal fire-fighting capacity• Oil is leaking from the bushing on the transformer secondary side
• Move immediately to put in place a structure designed to facilitate immediate deployment of staff in• The fire has caused extensive damage to the connecting ducts of the connecting bus line section on the transformer secondary side; thesufficient numbers in the event of a fire
bus line section is melted and broken in some places• Maintain chemical fire-fighting vehicles and other equipment required for oil fires• There does not appear to have been any other serious fire-related damage to date
• Provide dedicated communication lines for fire-fighting activities• Provide the relevant employees with more opportunity to work closely with fire-fighting services, such as
TEPCO press release: Reporting on safety levels
taking part in drills and exercises
Internal investigations are continuing in accordance with the directive from NISA dated July 16. A report of the findings, covering the2) Faster and more rigorous incident communication procedures
events, causes and responses, will be submitted to NISA, and preventative measures will be implemented as soon as practicable.
• Move immediately to put in place a structure for immediate deployment of staff to check for radioactive<NISA directive dated July 16>
leakage in the event of a fire due to earthquake or other cause
1) Investigation of causes why it took so long to deliver the report on the water leakage• Set up robust communication lines designed to withstand the effects of a fire due to earthquake or other2) Confirm the response to a transformer firecause and enable internal communication and communication between the plant and the emergency
3) Analyze seismic observation data from the earthquake and check safety (seismic resistance) of key equipment and facilities
headquarters set up by the operator• Inform local and national governments immediately of any confirmed or suspected leakage of radioactive
Power utilities: Report on findings of review of fire-fighting and incident communicating procedures and structuresmaterial
Report to NISA in response to written directive from NISA dated July 163) Check earthquake resistance with a view to public safety<Summary of directive>• Incorporate new information and insights gained from this incident into ongoing evaluation of earthquake
1) Report on an immediate review of fire-fighting procedures and structures in response to the fire at the nuclear power plant
resistance and facility safety levels
2) Report on an immediate review of the communication structure between nuclear plant and head office and between head office and• Review of the implementation program in order to complete the evaluation as quickly as possible (findings
the relevant government authorities in regards to incidents such as radiation leaks
should be made available within one month)
METI minister: non-scheduled press conference• Notwithstanding peripheral facilities and equipment, the key reactors themselves all shut down safely andautomatically as designed• Radioactive emissions from the power plant were detected; emissions from the Unit 7 main exhaust stack hadceased as of today. The volume of radiation generated thus far is equivalent to one part in ten million of thevolume of radiation that an average person would absorb from natural sources during normal daily activities.
Similarly, the radioactive water that leaked from the Unit 6 is equivalent to nine liters of hot water from aradon thermal spring, and will have no impact on the surrounding environment.
TEPCO• Site open to press (Unit 1 Diesel Oil Tank, Unit 3 House Transformer, No.4 Filtered Water Tank and etc.)

Saturday
July 21TEPCO press release: Earthquake update (as at 3:00 p.m.)• 63 issues confirmed to date (not including the four automatic reactor scrams at the time of the earthquake): no additions since July 201) Incidents related to radioactive materials (15 issues)2) Incidents NOT related to radioactive materials (52 issues, including the four automatic reactor scram due to the earthquake)• An analysis of reactor water from reactors 2 through 7, which were loaded with fuel, indicated no damage to the fuel. It is consideredhighly unlikely that fuel was damaged by the release of radioactive iodine, for several reasons: the iodine 131 concentration inside theNo. 7 reactor was normal at around 3 x 10-2 Bq/g during operation; after shutdown it fell to 9 x 10-3 Bq/g, according to analysis ofreactor water samples; and the high-sensitivity off-gas monitor reading declined after the emergency shutdown due to the earthquake.
• Summary of increased monitoring for radioactive emissions from the main exhaust stack of Unit 7<Radioactive iodine and particulate emissions from the main exhaust stack of Unit 7>
Sampling period
Radioactive iodine
Particulate matter
8
July 9 – 17
3 x 10 Bq
2 x 106 Bq
7
July 17 – 18
2 x 10 Bq
Not detected
July 18 – 19
Not detected
Not detected
July 19 – 20
Not detected
Not detected
Total
4 x 108 Bq
2 x 106 Bq<Radioactive iodine and particulate levels at boundaries of surrounding surveillance area>
Sampling
MP-1
MP-5
MP-8
periodIodineParticulates
IodineParticulates
IodineParticulates
July 18 – 20
Not detected
Not detected
Not detected
Not detected
Not detected
Not detected
July 21
Not detected
Not detected
Not detected
Not detected
Not detected
Not detected

Niigata Prefectural Government press release: Outcomes from site examination
Following the site inspection in accordance with the safety agreement (examination team accompanied bymembers of the Niigata Prefecture Environment Monitoring Council for Nuclear Power Plant Region), a publicstatement was issued to the effect that the radiation emissions were of such negligible levels as to be completely
harmless, with no health effects.
<Main items on inspection> Radiation leak in Units No. 6 and No. 7• Check radiation measurement data
• Inspect affected areas (both restricted and unrestricted) in the No. 6 reactor building• Confirm sampling procedure and measurement points used to monitor radioactive iodine emissions from main
exhaust stack of No. 7 reactor• Check radioactivity management at the site, such as definition of protected areas within the power plant<Feedback from members of the assessment committee >(1) Radioactive material discharged from the Unit No. 6 into the sea• The quantity of radiation discharged into the sea is equivalent to that contained in nine liters of hot water from aradon thermal spring• Radiation testing was conducted by prefectural authorities at the No. 6 discharge outlet and five points in theadjoining marine area, but found no radiation attributable to the nuclear plant• The measurement data and radiation management procedures and processes were deemed adequate• Preventative measures have been implemented and there is no danger of further leaks• Water quality in the marine area will be tested another two or three times in order to restore public confidence(2) Radioactive emissions from the Unit No. 7 main exhaust stack• Iodine not detected at any of the three prefectural radiation monitoring posts to date
• No radiation detected since TEPCO identified and rectified the problem on July 18• Total radiation up to July 18 was approximately 400 million Bq (= 1.3 mSv per 10,000,000), equivalent to
1/400,000 the level of a chest X-ray, or one ten millionth of the amount that an average person would absorb
from the natural environment (2.4 mSv) in other words, extremely low

Sunday July
22

TEPCO press release: Earthquake update (as at 3:00 p.m.)• 63 issues confirmed to date (not including the four automatic reactor scrams due to the earthquake): no additions since July 20<Radioactive iodine and particulate emissions from Unit No. 7 main exhaust stack>
Sampling period
Radioactive iodine
Particulate matter
July 20 – 21Not detected
Not detected
Total (July 9 – 21)
4 x 108 Bq
2 x 106 Bq<Radioactive iodine and particulate levels at boundaries of surrounding surveillance area>
Sampling
MP-1
MP-5
MP-8
periodIodineParticulates
IodineParticulates
IodineParticulates
July 22
Not detected
Not detected
Not detected
Not detected
Not detected
Not detected

Governor of Niigata Prefecture Hirohiki Izumida• Submits written request to national government regarding examination by IAEA group• “This incident has damaged local industry through rumor-mongering. In order to restore public confidence, wemust provide the outside world with full and accurate information”
Niigata Prefectural Government website: Radiation monitoring information (the first report)
To the people of Kashiwazaki-Kariwa• Radiation emissions from the No. 7 reactor at the Kashiwazaki-Kariwa nuclear power station ceased on the 18th
• The radiation dosage from emissions between the 16th and the 18th is equivalent to approximately 1/400,000 of
the radiation exposure in a standard chest X-ray, and has no effect on human health• Monitoring conducted by the Niigata Prefectural Government has detected no radiation emissions from thepower plant since the earthquake. There is therefore no cause for alarm.

TEPCO press release: Radiation measurements at the main exhaust stack of Unit 7 for July 22<Radioactive iodine and particulate emissions from Unit No. 7 main exhaust stack>
Sampling period
Radioactive iodine
Particulate matter
July 21 – 22
Not detected
Not detected
Total (July 9 – 22)
4 x 108 Bq
2 x 106 Bq

MondayJuly 23NISA press release: Earthquake update (the fifth report)• Information received from TEPCO (see left)• NISA Chairman Mr. Komoda visited Niigata prefecture today and met with the governor of Niigata prefecture,
the mayor of Kashiwazaki City and the mayor of Kariwa town to discuss the NISA response to the incident•
NISA
officers are currently at the plant:
TEPCO press release: Earthquake update (as at 3:00 p.m.)Thedata demonstrates that no iodine or particulates have been detected in the main air stack of the No. 7• 63 issues confirmed to date (not including the four automatic reactor scrams due to the earthquake): no additions since July 20
since
July 18.
1) Incidents related to radioactive materials (15 issues)- With respect to the leakage of radioactive material from the Nos. 6 and 7 reactors, NISA will be present at2) Incidents NOT related to radioactive materials (52 issues, including the four automatic reactor scrams due to the earthquake)the TEPCO investigation into the route taken by the water leak to determine whether the suspected route• The amount of puddle on the 5th floor below ground of the reactor combined building. 1,670m3 ==> 2,000m3
initially announced by TEPCO was correct• Radiation was not detected during regular testing for radioactive emissions at the main exhaust stacks of the Unit 1, 2 and 6. Unit 3, 4
• There are no significant changes in the main air stack radiation monitor and monitoring posts
and 5 will be tested tomorrow.
TEPCO press release: Investigation into leakage of radioactive matter in Unit 6
Following a thorough investigation, the water leak in the uncontrolled areas on the 3rd and mid 3rd levels of the reactor building was METI Vice Minister, Kitabatake: regular press conference
attributed to the following factors.
• In light of the growth of nuclear power throughout the world, it is most important to provide safety information• Water overflowed from the spent fuel pool on the operating floor on the 4th level of the reactor building and entered the fuel exchanger
about nuclear power around the world via the medium of the IAEA, and to share information about strategies
power supply box on the same floor, where it got into a cable duct via gaps in the seal around the cable passages in the box.
and initiatives. To this end, the Ministry has formally notified the IAEA today that its staffs will be permitted• The water traveled through embedded the cable duct, and dripped from upper air conditioning ducts on the mid 3rd level of the reactor
to visit the Kashiwazaki-Kariwa nuclear power plant in Japan.
building. It also dripped from openings in the mid 3rd level floor down to the 3rd level floor.
rd• Puddle on the 3 level floor surface drained out through drain outlets into a non-radioactive wastewater tank in the basement level.
From here, it was sent out to sea via discharge outlets
JANTI: On-site investigation (the team of 3 members) — until 24 JulyTEPCO press release: Radiation readings at the main exhaust stack of the Unit 7 for July 23
Radioactive iodine and particulate emissions from Unit 7 main exhaust stack
Sampling period
IodineParticulates
July 22 – 23
Not detected
Not detected
Total (July 9 – 23)
4 x 108 Bq
2 x 106 Bq

Tuesday
July 24

Minister of Economy, Trade and Industry Akira Amari: press conference following Cabinet meeting
1) Committee set up to investigate effect of the Chuetsu offshore earthquake on the nuclear power plant• The Committee, acting from the perspective of a third party, will conduct an in-depth examination of the
background to incidents such as the transformer fire and emissions of radioactive materials from the power
plant, and will use this to identify future issues to be addressed by the national government and operators of
nuclear plants. The Committee will be headed by Professor Haruki Madarame from Tokyo University, andTEPCO press release: Earthquake update (as at 2:00 p.m.)will report to the Nuclear Safety and Security Chapter of the Resources and Energy Study Group• In addition to the 63 issues confirmed to date (which excludes the four automatic reactor scrams at the earthquake), we have confirmed
2) IAEA delegation
damage to drive shaft joints on a ceiling crane in the No. 6 reactor building• Last week the IAEA requested access for a joint study mission. Our response is that Japan believes the• Radiation monitoring in the main exhaust stack was conducted at Unit 3, 4 and 5 but no radioactive material was detectedinternational sharing of information to be beneficial• Proposals from Japan:- IAEA delegation will be permitted to investigatie the site
- The incident will be discussed at the IAEA General Conference in September with senior officials from
regulatory bodies around the world- Japan will host an international workshop composed of expert consultants from around the world• We will continue to release information about the impact on the nuclear power plant in clear and simple
language in order to restore the confidence of local communitiesNISA press release: Earthquake update (6th report)• Information received from TEPCO (as per left-hand column)• TEPCO reports that since radiation has not been detected in the main air stack of the Unit 7 since July 19, themeasurement frequency will revert to weekly rather than daily as at present.
• NISA inspectors are currently inspecting the damage to the No. 6 ceiling crane• TEPCO is currently preparing to evacuate the water that has collected on the B5 level of the No. 1 reactor
combination building, by transferring water from the Unit 1 tank to the Unit 2. NISA inspectors aresupervising the use of temporary pools, pumps and hoses at the B5 level of the composite building, theunderground tunnel connecting Unit 1 and 2, and Unit 2 waste treatment facility.
• NISA inspectors were present at helium gas tests to determine the route taken by radiation that leaked from theUnit 6• No other significant developments in main exhaust stack radiation monitor and monitoring posts.

Wednesday
July 24

TEPCO• No. 6 reactor building and the turbine building operating floor (gallery room) opened to the media

Niigata Prefectural Government website: Radiation monitoring information (the second report)• No radiation has been detected in crops, livestock and marine produce sourced from the general area of thenuclear power plant• Fish and vegetables from Niigata prefecture are delicious as always and safe to eat• The radiation leak from the nuclear power plant on July 21 has been investigated in conjunction with radiation
experts• The level of radiation emissions was extremely small, with no effect on human health

TEPCO press release: Earthquake update (as at 3:00 p.m.)
NISA press release: Acknowledgement of accident and failure report and earthquake update (7th report)• Results of external inspection conducted after earthquake: 63 issues have been confirmed to date (not including the four automatic• NISA has received the Accident and Failure Report from TEPCO, along with an update on conditions at thereactor scram due to the earthquake)plant1) Incidents related to radioactive materials (15 issues)• Mr. Kato returned to the plant today for a further inspection together with NISA officials. The inspection2) Incidents NOT related to radioactive materials (52 issues, including the four automatic reactor shutdowns at the time of thecovered the scheduled manual testing of emergency diesel generators. No issues have been identified today.
earthquake)• The team is also inspecting the water in the B5 level of the No. 1 reactor combination building and the damage• Results of follow-up inspection: one issue (damage to drive shaft joints on a ceiling crane in the No. 6 reactor building)to drive section of the ceiling crane in the No. 6 reactor building.
• Scheduled manual startup testing was performed on one of the three emergency diesel generators in each of the No. 1, 2, 5 and 7• No other significant developments in the main air stack radiation monitor and monitoring posts.
reactors without error. Diesel generators in the No. 3, 4 and 6 reactors will be tested today.

Thursday
July 25TEPCO press release: Submission of report on nuclear plant accident and failure report and electrical damage report
NISA press release: safety check• Water containing radioactive material leaked into an unrestricted zone in the No. 6 reactor building (Operating Regulations Article 19,<Manual startup test on emergency diesel generators>
Paragraph 17, Item 9)• Manual startup tests were performed on seven emergency diesel generators today. All satisfied the safety• Water spilled on the operating floors of Nos. 1 through 7 reactor buildings (Operating Regulations Article 19, Paragraph 17, Item 10)
criteria.
• Damage was sustained to drive shaft joints on a ceiling crane in the No. 6 reactor building (Operating Regulations Article 19,• NISA will continue monitoring testing of the remaining emergency diesel generators to be completed by July
Paragraph 17, Item 3)
27.
• A fire occurred in the transformer (B) in the Unit No. 3 (Reporting Regulations on Electrical Incidents Article 3, Part 1, Item 3)<Confirmation of flooding on B5 level of No. 1 reactor combination building caused by damage to fire
protection system piping.>• Flooding on the B5 level of the reactor combination building entered the restricted area. As such, NISA
believes that the water should be treated as radioactive, irrespective of whether radiation monitoring shows
the levels to be below the detection limit.
• A system of pumps and hoses will be used to pump water from the waste output tank at the Unit 1 to thewaste output tank at the Unit 2. The transfer process will be checked by inspectors when appropriate.
<Confirmation of damage to drive shaft joints in ceiling crane in No. 6 reactor building>• Issued order for immediate check for similar damage to cranes in other reactor buildings. Further
investigation is required to identify causes of damage and prevent reoccurrence<Radioactivity monitoring>• NISA has questioned TEPCO regarding assessment of radiation exposure to workers since the day of theearthquake (July 16). NISA is satisfied that TEPCO is managing this area appropriately.
• NISA will continue to monitor radiation exposure assessment procedures as necessary.

TEPCO press release: Geological survey in surrounding marine area
• Insights from the Chuetsu offshore earthquake will be incorporated into an evaluation of anti-earthquake safety standards at the
Kashiwazaki-Kariwa nuclear plant• The seismic design of the power plant is based on detailed studies of the surrounding land and sea areas conducted at the time of theoriginal construction application• Sonic marine surveying will be conducted as part of geological studies of the sea area in the vicinity of the plant to evaluate the recent
seismic behavior including aftershocks

Friday July
26

TEPCO press release: Earthquake update (as at 3:00 p.m.)• All plants are shut down and stable at present. There are no significant changes in real-time data for the main air stack radiation
monitor and monitoring posts. There is no radiation impact on the surrounding environment.
• Plant update<Results of external inspection conducted after earthquake> 63 issues have been confirmed to date (not including the four automatic
reactor shutdowns at the time of the earthquake)1) Incidents related to radioactive materials (15 issues)2) Incidents NOT related to radioactive materials (52 issues, including the four automatic reactor shutdowns at the time of theearthquake)<Results of follow-up inspection> one issue (damage to drive shaft joints on a ceiling crane in the No. 6 reactor building)• Scheduled manual startup tests were performed on the second emergency diesel generator in each of the No. 1, 2, 5 and 7 reactors
without error. The same tests will be performed at the No. 3, 4 and 6 reactors today.
• The following issues, attributable to rain, have been confirmed. No radiation has been detected.
- Water has been discovered on the floor of in the low-pressure condensing pump room on the B2 level of the No. 1 turbine building.
This is believed to be rainwater that has entered the B1 level via a connecting corridor between the turbine building and theauxiliary building (and possibly from other points), and then flowed down to the B2 level.
- A water leak has been discovered in the wall of the south corridor on the B1 level of the No. 3 turbine building. It is believed thatthe water has collected in the pit adjoining the turbine building, then traveled along wiring tunnels into the turbine building.
- Water has been discovered on the floor of the B1 level of the solid waste storage warehouse in the vicinity of the boundary between
the No. 1 building and the administration building. It is believed to be rainwater which has been absorbed into the ground andsubsequently risen up.
- Water has been discovered on the floor of the B1 level of the auxiliary building. It is believed to be rainwater which has beenabsorbed into the ground and subsequently risen up.

METI press release: Establishment of Committee to Investigate Impact of Chuetsu-Oki earthquake on
Nuclear Power Plant Facility (provisional title)
The Committee investigation will examine in depth the effects of the Chuetsu-Oki earthquake on the
Kashiwazaki-Kariwa nuclear plant and report to the national government and the operator of the plant on future
actions and other considerations<Specific issues to be examined>
1) Adequacy of internal fire protection procedures at the time of the earthquake, as well as reporting andliaison structures and information disclosure to local communities
2) Evaluation of seismic safety standards at the plant in light of outcomes from the Chuetsu-Oki earthquake3) Operational procedures and equipment and facility safety at the plant at the time of the Chuetsu-Oki
earthquakeNISA press release: Earthquake update (8th report)• Information received from TEPCO (as per column on the left)• Mr. Kato and the NISA inspectors continued today with their on-site investigations; they witnessed scheduled
manual testing of emergency diesel generators and reported no errors.
• They also inspected the site of the flooding that was confirmed today, and confirmed that no radiation was
detected. TEPCO was instructed to identify and repair the sources of the leakage.
• No other significant developments in the main air stack radiation monitor and monitoring posts.
NISA press release: safety checks<Manual startup tests on emergency diesel generators>• Manual startup tests were performed on seven emergency diesel generators today, and all satisfied the safety
criteria• NISA will monitor manual startup tests to be performed on the remaining six emergency diesel generators on
July 27<Water leak (suspected rainwater)>• The newly discovered leaks are believed to be primarily the result of earthquake damage to pipe tunnels
leading into the building. TEPCO was instructed to identify the entry route and repair and/or rectify asnecessary<Damage to drive shaft joints on ceiling crane in reactor building>• In light of confirmed damage to the drive shaft joints of the ceiling crane in the No. 6 reactor building, thedrive shaft joints of the ceiling cranes in the No. 2 and No. 3 reactor buildings were also inspected• There were no safety issues according to the on-site inspectors. The remaining ceiling cranes will beinspected in due course.

Power utilities: Submission of upgrade programs for internal fire protection systems and incident reporting structuresNISA press release
Upgrade programs to be submitted in accordance with a directive from the Ministry of the Economy, Trade and Industry (METI)• NISA today received reports of upgrade programs from nuclear plant operators in relation to 1) Strengthening
dated July 20 (parts 1) and 2) only at this stage)of internal fire protection systems and 2) Faster and more accurate incident reporting in accordance with theRequirements of METI directive
Ministerial directive dated July 20.
1) Strengthening of internal fire protection systems• A Working Group on disaster response procedures will be set up within the Committee to Investigate Impact of2) Faster and more accurate incident communication
Chuetsu-Oki earthquake on Nuclear Power Plant Facility in conjunction with the Fire and Disaster3) Assessment of seismic safety standards predicated on public welfare
Management Agency (FDMA). The sub-committee will take three months to investigate internal fire
protection systems and reporting and liaison structures. The recommendations from the sub-committee will be
expected to contribute to improvement of the emergency response programs of power utilities.

Friday July
27

TEPCO website
Nuclear Safety Commission secretariat: Nihon Keizai Shimbun newspaper article
Presentation of Impact of Niigata Chuetsu Earthquake on Nuclear Plant with photographs, describing reactors and other facilities and
The Nuclear Safety Commission wishes to refute claims made in an article which appeared in today’s edition ofequipment
the Nihon Keizai Shimbun newspaper, entitled Tougher Seismic Protection Standards Nuclear Safety
Commission demands Mandatory Disclosure of Major Failure Risk. The Nuclear Safety Commission has madeno such demand.
<Summary of article> The national Nuclear Safety Agency on July 26 resolved to amend guidelines for seismic
TEPCO press release: Earthquake update (as at 3:00 p.m.)design standards at nuclear power plants. The revised guidelines will require disclosure of• Manual startup tests were performed on 20 of the emergency diesel generators in Units 1 through 7, with no errors reported
the estimated risk of occurrence of major failures, together with associated remedial work
• Update on impact of rainwater in restricted area
to minimize the risks. The Nuclear Safety Commission plans to introduce the amendments<No. 1 turbine building>in FY2008.
On July 26, water was pumped from the low-pressure condensing pump room on the B2 level of the No. 1 turbine building andinto the waste treatment system
On July 27 it was confirmed that there was no water in the B1 level of the turbine building. However, water is continuing totrickle in from the connecting corridor between the turbine building and the auxiliary building<No. 3 turbine building>
NISA press conference: Earthquake update (9th report)
On July 26, the water was removed. On July 27, it was confirmed that there was no more water leaking into the turbine• Information received from TEPCO (see column on left)
building.
• NISA officers attended the scheduled manual startup tests of all except one of the emergency diesel generators<Solid waste storage facility>
and confirmed that all operated as normal and satisfied the NISA requirements
On July 26, removal of water was completed. On July 27, it was confirmed that there was no more water leaking into the• In light of confirmed damage to the drive shaft joints on a ceiling crane in the No. 6 reactor building, we havefacility.
inspected the Nos. 1, 2 and 3 reactors, finishing today, and have found no problems<Auxiliary building>• No other significant developments in the main air stack radiation monitor and monitoring posts
On July 27, it was confirmed that there was no more water leaking into the turbine building.
• All plants are shut down and stable at present. There are no significant changes in real-time data for the main air stack radiation
NISA press release: negative impact of overseas reporting of the incident
monitor and monitoring posts. There is no radiation impact on the surrounding environment.
The government has taken the following steps to address the negative impact of overseas reporting of the
TEPCO press release: Results of regular manual startup tests on diesel generators• Manual startup tests were conducted on emergency diesel generators in the Nos. 1 through 7 on July 25 – 27
• The scheduled tests were completed at 3:19 p.m. today with all equipment confirmed in good working order
TEPCO press release: Executive Vice-President relocates to Kashiwazaki-Kariwa region• TEPCO Executive Vice-President Ichiro Takekuro will relocate to the Kashiwazaki-Kariwa area near the plant from July 30 in order tocoordinate the response

incident• In order to address misperceptions created by inaccurate reporting by some overseas media outlets on theincident at the Kashiwazaki-Kariwa nuclear power plant, the government on July 26 directed that
information be provided via the Ministry of Foreign Affairs to its diplomatic establishments abroad for
distribution to the governments of all major nations and in particular those nations where inaccurate
reporting has occurred
Ministry of Foreign Affairs website: Impact of earthquake at the Kashiwazaki-Kariwa nuclear power plant
The following information has been posted in Japanese and English on the Ministry of Foreign Affairs website:• The recent major earthquake triggered a fire at an electrical transformer in the Kashiwazaki-Kariwa Nuclear
Power Plant• However, there was no problem with regard to the safety of the nuclear reactors because the reactors whichwere running at the time of the earthquake were all shut down automatically by safety mechanisms.
• As a result of the earthquake, a negligible amount of radioactive material was released from the Unit No 7 into
the atmosphere, while water containing radioactive material was released from the Unit No 6 into the sea. In
both cases, the radioactivity levels were well under the legal safety standards, and there was no impact
whatsoever on the surrounding environment. The leaks have already been stopped.
• Unfortunately, certain news media have created misperceptions through inaccurate and/or inappropriate
reporting of the situation, which has adversely affected tourism and other industries in Japan.
• Japan has provided relevant information to the International Atomic Energy Agency (IAEA) since the incident
and, in a bid to promote international cooperation in the field of nuclear safety, has agreed to admit a teamfrom the IAEA for the purpose of conducting a joint examination which will provide objective proof of thecurrent safety of the Kashiwazaki-Kariwa Nuclear Power Plant, boost transparency in the domestic nuclear
energy industry, and enable lessons learned from the earthquake to be shared among the international
community.
Niigata Prefectural Government website: Radiation monitoring information (No. 3)• No radiation has been detected in the three bathing areas in the City of Kashiwazaki, nor in any of the main
bathing areas in the prefecture. Swimming in the sea poses no risk to the health. 。

Monday
July 30TEPCO press release: Earthquake update (as at 2:00 p.m.)• Regular monitoring of radiation levels at the main air stack was conducted at the No. 1, 2 and 6 reactors and no radioactive matter was
detected (July 23 – 30)• All plants are shut down and stable at present. There are no significant changes in real-time data for the main air stack radiation
monitor and monitoring posts. There is no radiation impact on the surrounding environment.
TEPCO press release: Analysis of seismic observation data (1st report)
We studied seismic observation data on the Chuetsu-Oki earthquake in accordance with the written directive received from NISA on
July 16. A report of the analysis findings to date with respect to analysis of the seismic observation data generated in the mainearthquake (the 1st report) was today submitted to NISA.

NISA press release: Earthquake update (10th report)• Information received from TEPCO (see column on left)• NISA officers are currently confirming details of the TEPCO plant study such as causal factors and othermatters• No other significant developments in the main air stack radiation monitor and monitoring posts
NISA press release: Analysis of seismic observation data (Part 1)• NISA has received from TEPCO the first report of the analysis of seismic observation data from the Chuetsu-Oki
earthquake in accordance with the directive dated July 16• NISA will scrutinize the report thoroughly in conjunction with expert consultants

We will continue gathering data records for the aftershocks. This data will be analyzed to evaluate the safety of key equipment andNuclear Safety Commission
facilities.
The Nuclear Safety Commission today approved an Opinion Statement on the Impact of the Earthquake and<NISA directive (July 16)>
Future Actions as follows:• Analyze seismic observation data for the earthquake<New Seismic Guidelines>• Evaluate safety levels of key safety-related equipment and facilities
Any decision about reviewing the new seismic guidelines should be made on the basis of an evaluation of the<Summary of report>
impact of the recent earthquake using the seismic motion stated in the new seismic guidelines in accordance1) Observation records
with the back check procedure. We are not able to give a decision at this stage.
• Examples of acceleration time history waveforms for foundations of Nos. 1 through 7 reactor buildings<Load-bearing performance of buildings and structures>• Sample comparison of floor response spectrum based on observation records versus floor response spectrum based on seismic• The new seismic guidelines state that buildings and structures must be erected on solid foundations toground motion as per seismic response analysis model used at the original design stage for foundations of Nos. 1 through 7
provide adequate load-bearing performance. This applies to all buildings and structures (not just key
reactor buildings
buildings and structures as in the previous seismic guidelines.)
2) Analysis of seismic observation data
• There are a number of instances where the earthquake has caused serious damage to equipment, machinery,
We will continue gathering data records for the aftershocks. This data will be analyzed to determine seismic motion in relation topipes and ducts, generally due to uneven subsidence of foundations.
evaluation of seismic protection during the earthquake, and to determine seismic motion in the free rock surface (excluding the• For this reason, it is considered necessary to assess the load-bearing performance of foundations with respect
effect of the upper foundations)
to conformance with the new principles, for B and C classes as well as S class, and to carry out3) Seismic protection for key safety-related equipment and facilities
reinforcement work where necessary as determined on the basis of the assessment
The seismic motion figures used in the safety evaluation will be used to analyze seismic response and seismic protection of key<Residual risk evaluation>
safety-related equipment and facilities
Much of the residual risk PSA process is predicated on evaluations that are yet to be performed. The Nuclear4) Seismic protection assessment in future
Safety Commission will ask the operator to perform quantitative evaluation on a trial basis and will conduct its
Information obtained through an investigation into active fault lines in the marine area and analyses of seismic observation data
own investigation with a view to introducing residual risk PSA at some point in the future.
will be used to identify potential improvements and modifications to seismic protection assessment and strategies in future<Upgrading of earthquake-related fire protection systems>• The Fire Protection System Guidelines from the Nuclear Safety Commission require fire protection systems
Table: Seismic acceleration observations (with design acceleration response at the same location shown in brackets)
to be designed so that they can continue functioning in the event of simultaneous earthquake and fire
Seismic acceleration (with design acceleration response
outbreakObservation SpotNotes
at the same location shown in brackets), in gal• Given that fire protection systems did not function properly in the recent earthquake, we will investigate the
S-N
E-W
Verticallevel of adherence to the guidelines and consider upgrades to the fire protection system
Unit 1

Reactor
Building
TurbineBuilding
Reactor
Building

Unit 2
TurbineBuilding

Unit 3

Unit 4

Unit 5

Unit 6

Reactor
Building
TurbineBuilding
Reactor
Building
TurbineBuilding
Reactor
Building
TurbineBuilding
Reactor
Building
Reactor
Building

Unit 7

TurbineBuilding

2F
B5F(on the foundation mat)599(460)
311(274)884(463)680(273)394
408

1F(pedestal)1862(274)

1459(274)

741

2F
517(271)
B5F(on the foundation mat)
1F
1F(pedestal)
B3F(on the foundation mat)
2F
B5F(on the foundation mat)1F(pedestal)
B3F(on the foundation mat)
2F
B5F(on the foundation mat)
1F
1F(pedestal)
B3F(on the foundation mat)
3F
B4F(on the foundation mat)517(271)718(271)412

304(167)431(295)
642(588)387(233)
525(314)308(192)1350(854)
581(239)606(299)
310(193)411(269)614(832)348(238)472(354)277(249)606(167)764(259)1159(478)
681(232)650(309)384(193)2058(834)
549(243)713(293)492(194)560(267)763(838)442(242)697(350)442(254)

282
594
650
470
518
311
619
513
548
337
549
526
443
331
205

2F(pedestal)

1166(995)

1157(754)533

3F
B3F(on the foundation mat)
3F
B3F(on the foundation mat)
2F
2F(pedestal)
B2F(on the foundation mat)554(415)271(263)367(415)267(263)418(394)
673(1096)

545(411)322(263)435(411)356(263)506(418)1007(859)

578
488
464
355
342
362

318(299)322(312)336

TEPCO press release: Earthquake update (as at 3:00 p.m.)• In new developments, thin oil films have been confirmed on the No. 1 turbine building sub-drain and the discharge outlets for the Nos.
1 – 4 reactors. Fluid discharge out the sub-drain has been stopped and a temporary tank is being prepared. Oil film at the discharge
outlets is being monitored continuously while the sub-drain is stopped.
• Scheduled radiation monitoring of the main exhaust stack was conducted on the Units No. 3, 4, 5 and 7 and no radioactive matter was
detected. (No. 3, 4 and 5 reactors: July 24 – 31; No. 7 reactor: July 23 – 31)• 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.

Tuesday
July 31NISA press release: Earthquake update (11th 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
First meeting of the Committee to Investigate the Impact of the Chuetsu-Oki earthquake on the Nuclear
Power Plant Facility
The Working Groups have been set up to investigate specific areas as listed below. The Committee will deliberateon the basis of their reports.
1) Internal fire protection procedures at the time of the earthquake, reporting and liaison structures, andinformation disclosure to local communities>> Working Group to investigate internal fire protection procedures and reporting and liaison structures at
the nuclear power plant in the event of the Chuetsu offshore earthquake (provisional title)
Chair: Professor Miya, Visiting Professor at Hosei University Graduate School2) Evaluation of seismic safety standards at the plant in light of outcomes from the Chuetsu-Oki earthquake>> Existing sub-committee on seismic safety and structural design
Chair: Professor Abe, Emeritus Professor at Tokyo University3) Operational management and equipment and facility safety at the plant at the time of the Chuetsu-Oki
earthquake and future strategies>> Working Group on operational management and equipment safety assessment (provisional title)
Chair: Professor Sekimura from Tokyo University Graduate School