Announcements
Status of the Fukushima Daiichi and Fukushima Daini Nuclear Power Stations after the Earthquake that occurred on February 13, 2021 (As of 2:00 PM, February 14)
February 14, 2021
Tokyo Electric Power Company Holdings, Inc.
◦ At 11:08 PM, February 13, 2021, a magnitude 7.3 earthquake* (tentative assessment) struck off the coast of Fukushima Prefecture.
*Magnitude on Japanese seismic intensity scale: Futaba Town: 6-Strong; Okuma Town: 6-Weak; Naraha Town: 6-Weak; Tomioka Town: 5-Strong
◦ At current time, there are no abnormalities at the Fukushima Daiichi Nuclear Power Station or Fukushima Daini Nuclear Power Station that would have an impact off site.
◦ Data from the Fukushima Daiichi Nuclear Power Station and Fukushima Daini Nuclear Power Station related to the earthquake (inspection status, etc.) is as follows.
･ Fukushima Daiichi Nuclear Power Station
◦ Ground acceleration
Unit 6 Lateral: 235.1Gal Vertical: 116.5Gal
◦ Primary sequence of events
February 13
Around 11:08 PM: Earthquake occurs
11:08 PM: Fire alarm sounds in the hallway on the south side of the first floor of the seismic isolation building.
Around 11:10 PM: Drop in indicated level on the wharf drainage channel monitor. It is assumed that the measurement level dropped because radioactive substances adhered to the inside of the water tank being monitored for radiation flaked off as a result of the earthquake. Leaks upstream of the aforementioned drainage channel have not been found, and there have been no significant fluctuations in seawater radiation monitors (Gross beta indicators), so there is no impact on the environment.
11:20 PM: Fire alarm sounds in the large rest facility.
11:23 PM: Nuclear alert order issued.
11:33 PM: Accumulated water transfer equipment and water treatment equipment is shut down.
11:55 PM: The following checks are made:
Plant parameters for Units 1~6: No abnormalities
Reactor cooling water injection equipment (Units 1~3): Operation
uninterrupted
Spent fuel pool cooling equipment (Units 1, 2, 3, 5, 6*, common pool):
Operation uninterrupted
*Unit 4 equipment was shut down prior to the earthquake
Monitoring post indicators: No significant
fluctuation
Station site boundaries/on-site dust monitor indicators: No significant
fluctuation
Onsite dose display indicators: No significant
fluctuation
Seawater radiation monitors/on-site drainage channel monitor indicators:
No significant
fluctuation
11:59 PM: Futaba Fire Station (general line) notified
February 14
0:07 AM: Field inspection reveals no abnormalities in response to the fire alarm in the hallway on the south side of the first floor of the seismic isolation building.
0:55 AM: Patrols commenced (Zone III).
1:09 AM: Parameters for Units 1~6 facilities, water treatment facilities, and miscellaneous solid waste incinerator facilities confirmed in the central monitoring room. No abnormalities found.
1:10 AM: Patrol of miscellaneous solid waste incinerator facilities. No abnormalities found.
From 0:14 AM: Slight increase in on-site dust monitor readings seen in five locations. Maximum spike seen in the aforementioned dust monitors was 1.6×10-5Bq/cm3 (Unit 3, ocean side), but this value is small compared with the alarm setting (High alarm setting: 5.0×10-5Bq/cm3) and within the range of normal fluctuations (Range of normal fluctuations: 2×105Bq/cm3~5×10-6Bq/cm3). Readings returned to levels indicated prior to the earthquake at around 2:00 AM.
1:36 AM: Field inspection reveals no abnormalities in response to the fire alarm in the large rest facility.
Around 2:08 AM: Patrols of the Unit 5 and Unit 6 reactor buildings conclude. Puddles were discovered near the spent fuel pools for Unit 5 and Unit 6. It is assumed that water overflowed from the pools during the earthquake. There is no continual overflow and no off-site impact. No other abnormalities were found at the reactor buildings.
<Unit 5>
Location: Reactor building operating floor, four locations At all four locations the size of the puddles was 0.5 m x 0.3 m x 1mm (Approximately 600mL)
<Unit 6>
Location: Reactor building operating floor, four locations
-2m x 0.5m x 1mm
-1m x 0.5m x 1mm
-0.1m x 0.1m x 1mm
-0.2m x 0.1m x 1mm (Total: Approx. 1,600mL)
2:24 AM: Unit 5 waste treatment building patrol concludes. No abnormalities found.
2:36 AM: Unit 3/4 main control room and Unit 3/4 turbine building controls conclude. No abnormalities found.
3:07 AM: Unit 6 waste treatment facility patrol concludes. No abnormalities found.
3:13 AM: Treated water storage tank area patrol concludes. No abnormalities found.
3:16 AM: Water treatment facility patrol concludes. No abnormalities found.
3:17 AM: Unit 5/6 turbine building patrol concludes. No abnormalities found.
Around 3:50 AM: Patrol of common auxiliary facilities in use concludes.
Puddles were discovered near the spent fuel pools in the aforementioned facilities. It is assumed that water overflowed from the pools during the earthquake. There is no continual overflow and no off-site impact.
No other abnormalities were found with auxiliary common facilities in use.
Location: Spent fuel pools inside auxiliary common facilities in use.
-6m x 0.1m x 1mm (Approx. 600mL)
3:35 AM: Monitoring posts checked. No abnormalities found.
3:47 AM: Weather measurement equipment checked. No abnormalities found.
Around 5:00 AM: Water leak found under the F tank area H3 tank flange. The tank is being used to store water that had accumulated in the subfloors of the Unit 5/6 reactor building. The leak was contained within the weir, and there is no off-site impact.
Connection valves were closed to isolate the aforementioned tank, but to the leak continues from five locations at the bottom flange of the tank.
By around 6:45 AM: It is confirmed that there are no abnormalities with the following systems:
Unit 1~4 facilities:
-Reactor cooling water injection system
-Primary containment vessel gas management system
-Nitrogen gas injection system (System A, System B, emergency system)
-Spent fuel pool cooling systems
Around 10:46 AM: Puddle found in the J9 tank area. The water was contained inside the weir built to prevent large leaks and no water has been found outside the weir.
Thereafter, an analysis of the water from the puddle revealed that the saline content was 0%, the pH was 8, and the level of radioactivity is the same as background radiation. It was therefore determined that the water was rain that had seeped between the painted surface and the concrete weir.
1:01 PM: Since no abnormalities were found with accumulated water transfer equipment, the transfer of water from the Unit 1 reactor building to the process main building was recommenced. Accumulated water transfer at other buildings was also gradually recommenced.
1:26 PM: Analysis of the water from the wharf drainage channel found cesium-137 consternation to be 2.3Bq/L, and gross beta concentrations to be 7.3Bq/L, which is consistent with normal readings.
1:51 PM: All [Zone III] patrols concluded. It was reaffirmed that there were no significant fluctuations with monitoring data. Furthermore, during patrols of waste-related facilities, some containers in temporary storage facilities in the rubble storage area were found to be leaning or toppled, but the contents of these containers had not dispersed.
2:00 PM: Nuclear alert order rescinded. (An earthquake with seismic intensity 6-Weak or higher in the location municipality)
･ Fukushima Daini Nuclear Power Station
◦ Ground acceleration
Unit 1 Lateral: 207.3Gal Vertical: 225.8Gal
◦ Primary sequence of events
February 13
Around 11:08 PM: Earthquake occurs
11:08 PM: Unit 1~4 spent fuel pool water level high/low alarm sounds.
11:08 PM: Unit 1~4 spent fuel pool water level high/low alarm light goes out.
11:17 PM Nuclear alert order issued
11:46 PM Unit 3/4 patrols commenced [Zone III]
February 14
0:05 AM: Waste treatment building patrol commenced [Zone III]
0:08 AM: Unit 1/2 patrol commenced [Zone III]
0:09 AM: It is confirmed that the fire alarm that sounded for Units 1/4 was an error.
Parameters confirmed in the central monitoring room. No abnormalities found.
0:21 AM: It is confirmed that there is no overflow/leaks from the Unit 4 spent fuel pool.
0:31 AM: It is confirmed that there is no overflow/leaks from the Unit 3 spent fuel pool.
0:40 AM: It is confirmed that there is no overflow/leaks from the Unit 2 spent fuel pool.
0:47 AM: Overflow found from the Unit 1 spent fuel pool.
(Approx. 160mL, contained by weir)
6:30 AM: All patrols (Zone III) concluded. Patrol results are as follows:
-Overflow/leak found at the Unit 1 spent fuel pool.
(Approx. 160mL)
-Leaking water found from the Unit 2 reactor building 5th floor duct chamber (approximately 90mL)
-Leak found at the site bunker building pool (approximately 1.4L)
*The aforementioned leaks had no impact on spent fuel pool cooling.
-No abnormalities found that the aforementioned facilities.
-No significant fluctuations in the exhaust stack monitors or monitoring post readings have been seen, and there is no off-site impact from this earthquake.
6:43 AM: Nuclear alert order rescinded. (An earthquake with seismic intensity 6-Weak or higher in the location municipality)
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