Dear Friends,
We have started PCV flooding from 10:01pm, May 5th with increased water injection from 6.0 à 8.0 m3/h. Please see updates of Plant Status at Fukushima Daiichi NPS below.
Contacts:
TEPCO Washington Office: 202-457-0790
Kenji Matsuo, Director and General Manager
Ikuo Nishimura, Deputy General Manager,
Masayuki Yamamoto, Manager, Nuclear Power Programs
◇ Transference of water of Unit 2 to Central Radioactive Waste Treatment Facility
- Water level increase at Process Main Building since the start of the transfer: 1,834 mm as of 7:00 am on May 6th.
- From May 1st, transferring water accumulated in the basement of the turbine building of Unit 6 to temporary tanks was started. No transfer on May 5th, transferring water approximately 120m3 on May 6th.
◇ Water level at the vertical shaft of the trench and T/B (As of 7:00 am, May 5th)
Vertical Shaft of Trench （from top of grating to surface） | Turbine Building | |
Unit 1 | O.P. +2,060 mm （1,940 mm） No change since 7:00 am, May 5th | O.P. +5,050 mm No change since 7:00 am, May 5th |
Unit 2 | O.P. +3,130 mm (870 mm) 20mm decreased since 7:00 am, May 5th | O.P. +3,100 mm No change since 7:00 am, May 5th |
Unit 3 | O.P. +3,170 mm (830 mm) 20mm increased since 7:00 am, May 5th | O.P. +3,100 mm No change since 7:00 am, May 5th |
Unit 4 | － | O.P. +3,200 mm No change since 7:00 am, May 5th |
- From May 1st, Blockage at the vertical shaft of trench is being implemented at Unit 2.
- Result on May 5th
【Unit 4】 From around 12:19 pm to 8:46pm, fresh water spraying started by the concrete pumping vehicle (approximately 270t).
- Plan and Result on May 6th
【Unit 2】 From 9:36 am to 11:16 am on May 6th, we conducted water spray, using temporary electric pump.
【Unit 4】From 12:38 pm on May 6th, we started water spay by the concrete pumping vehicle.
【Unit 1】 Injecting fresh water:
Reactor pressure vessel temperature:
At 11:00am, May 6th, 134.1 C
At 10:01 am on May 6th, in order to make nuclear reactor flooded to TAF, we have increased the amount of injecting freshwater from approximately 6 m 3/h to approximately 8m 3/h. (see additional information below)
【Unit 2】 Injecting fresh water
Reactor pressure vessel temperature:
At 11:00am, May 6th, 116.4 C
【Unit 3】 Injecting fresh water
Reactor pressure vessel temperature:
At 11:00am, May 6th, 147.4C
- At 10:09 am, on May 4th, in response to the increased temperature at RPV, we increased freshwater injection rate from 7.0 m 3/h to 9.0m 3/h. We are closely monitoring effect of increased water flow to the temperature. If the temperature continues to increase, we are planning to change flow rate to 10.0m3/h with boron.
【Unit 4】 【Common spent fuel pool】No particular changes on parameters.
【Units 5/6】 Reactor cold shutdown. No particular changes on parameters.
On May 5th, TEPCO received an instruction from NISA on “Implementation of a measure to flood the primary containment vessel to TAF in Unit 1 of Fukushima Daiichi Nuclear Power Station” .
In compliance with the implementation instructions from NISA, and ensuring safety, we will steadily implement flooding process described in the report submitted to NISA on May 5th.
NISA requests TEPCO follow the instructions below with absolute accuracy to secure sufficient degree of safety.
1. Implement sufficient monitoring for the water level inside and leakage from the PCV. In addition, implement the flooding process as previously planned, including the cautious control of water injection rate to avoid over depressurization in the PCV.
2. Examine the seismic reinforcements to the supporting posts of the suppression chamber if the working environment in the reactor building allows, since the continued occurrence of aftershocks is to be expected.
- From 1:31 am, April 7th, we started to inject nitrogen gas to PCV using temporary nitrogen generators and D/W pressure was 156.3kPaabs before the injection.
- D/W pressure has changed to 134.8kPaabs, as of 11:00am, May 6th. The injected amount of nitrogen gas was approx. 19,300m³.
◇ Density of Iodine 131 in the seawater (Reference purpose)
Density limit by the announcement of Reactor Regulation: 0.04Bq/cm3
Sampling: Everyday
The latest results show Iodine 131 density was below regulatory limit (0.04Bq/cm3) or N.D. at every sampling location.
Sampling Location (seacoast) | Date | Time | Density（Bq/cm3） | Ratio to Criteria（times） | |||
Approx. 30m north to Discharge Canal of Units 5 & 6 of Fukushima Daiichi | 5/5 | 9:40 | 14:35 | 0.0098 | N.D. | 0.25 | - |
Approx. 330m south to Discharge Canal of Units 1 to 4 of Fukushima Daiichi. | 5/5 | 9:10 | 14:10 | 0.017 | 0.077 | 0.43 | 0.19 |
Around the north Discharge Canal of Fukushima Daini (10km from Fukushima Daiichi) | 5/5 | 8:30 | N.D. | - | |||
Around Iwasawa Seashore (approx. 16km from Fukushima Daiichi) | 5/5 | 8:05 | N.D. | - | |||
We are expanding sampling location (will add 7 more locations) and started monitor upper and lower layer of one point (will increase locations with multi layers monitoring).
Sampling Location (offshore) | Date | Time | Density（Bq/cm3） | Ratio to Criteria（times） |
Approx. 3km from the offshore of Soma City, upper layer | 5/5 | 10:20 | N.D. | - |
Approx. 3km from the offshore of Soma City, lower layer | 5/5 | 10:20 | N.D. | - |
Approx. 3km from the offshore of Haramachi Ward, Minamisoma City | 5/5 | 10:32 | N.D. | - |
Approx. 3km from the offshore of Odaka Ward, Minamisoma City | 5/5 | 10:12 | N.D. | - |
Approx. 3km from the offshore of Iwasawa, Naraha Town | 5/5 | 8:11 | N.D. | - |
Approx. 3km from the offshore of the north of Iwaki City | 5/5 | 7:45 | N.D. | - |
Approx. 3km from the offshore of Natsuigawa River, Iwaki City | 5/5 | 7:15 | N.D. | - |
Approx. 3km from the offshore of Onahama Port, Iwaki City | 5/5 | 6:02 | N.D. | - |
Approx. 3km from Ena, Iwaki City | 5/5 | 6:19 | N.D. | - |
Approx. 3km from Numanouchi, Iwaki City | 5/5 | 6:57 | N.D. | - |
Approx. 3km from Toyoma, Iwaki City | 5/5 | 6:41 | N.D. | - |
Approx. 8km from the offshore of Odaka Ward, Minamisoma City | 5/5 | 10:05 | 0.0031 | 0.08 |
Approx. 8km from the offshore of Iwasawa, Naraha Town | 5/5 | 8:33 | N.D. | - |
Approx. 15km from the offshore of Minamisoma City | 5/5 | 9:05 | N.D. | - |
Approx. 15km from the offshore of Ukedo River, Namie Town | 5/5 | 9:30 | N.D. | - |
Approx. 15km from the offshore of Fukushima Daiichi | 5/5 | 9:05 | N.D. | - |
Approx. 15km from the offshore of Fukushima Daini | 5/5 | 8:40 | N.D. | - |
Approx. 15km from the offshore of Iwasawa Seashore, Naraha Town | 5/5 | 8:15 | N.D. | - |
Approx. 15km from the offshore of Hirono Town | 5/5 | 7:55 | N.D. | - |
- From May 2nd, preparation work to install the ambient air filtration system is conducted in order to improve the work environment in the reactor building of Unit 1.
At 16:36 on May 6, air ventilation is commenced in reactor building by six (total 6) ambient air filtration system.
- TEPCO English website
- METI(Ministry of Economy Trade and Industry)
- NISA(Nuclear and Industrial Safety Agency) http://www.nisa.
- JAIF(Japan Atomic Industrial Forum Inc.)
- FEPC(The Federation of Electric Power Companies of Japan)
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