Status of the Fukushima Daiichi Nuclear Power Plant
Status of the Fukushima Daiichi Nuclear Power Plant Updated information (19-05-2011 at 1300hrs) (Prepared by Health Safety & Environment Group) 1. Current situation Overall, the situation at the Fukushima Daiichi nuclear power plant remains very serious. Plant Status Restoration of AC Power TEPCO reported that as of 30 April the voltage of offsite power for Unit 3 and 4 was upgraded from 6.9 kV to 66 kV in order to secure power supply capacity in the future. On 03:00 UTC 13 May, NISA reported that in order to reinforce the power supply for Units 3 and 4, the 480V power distribution panel for Unit 4 and the Common Spent Fuel Pool was reconnected in order to receive power from Tohoku Electric Power Company’s Tohden Genshiryoku line (66kV) instead of the Okuma No.3 power transmission line. On 06:00 UTC 12 May, NISA reported that because of the restoration of the Okuma No. 2 Power Transmission Line, part of power supply for Unit 1 and Unit 2 is received from its power transmission line. Status of Unit 1 The rate of water injection into the Reactor Pressure Vessel (RPV) of Unit 1 was changed from 8 m3/h to 10 m3/h at 20:28 UTC 15 May and was still 10m3/h at 20:00 UTC 16 May. The temperature of the RPV is 92.8 oC at the feed water nozzle and 80.7oC at the lower head at 21:00 UTC on 16 May. Nitrogen gas continues to be injected into the Unit 1 Containment Vessel. From 23:50 UTC 10 May to 02:14 UTC 11 May, NISA report confirms the water level gauge of the reactor pressure vessel and the pressure gauge of the containment vessel were calibrated. All units of the ambient air filtration system (a total of 6 units) were installed to improve the working environment of the reactor building and are operational as of 05:36 UTC 5 May. The filtration system operated till 8 May at 11:02 UTC; subsequently TEPCO opened the airlock of the reactor building at 11:08 UTC on 8 May by cutting and only partially opening the filtration system duct, in order to avoid sudden changes in ambient air inside the reactor building. As a result of opening the airlock it has been estimated that the following activities of radionuclides were released to the environment:
TEPCO prepared an environmental impact assessment on the release, which was independently verified. The assessment concluded that the predicted maximum exposure is sufficiently low compared to 1 mSv, the dose limit for the public.
Status of Unit 2 Injection of fresh water into the RPV was on-going, at a rate of about 7.0 m3/h, as reported at 20:00 UTC on 16 May. The temperature of the RPV at the feed water nozzle was 113.5ºC at 20:00 UTC on 16 May. According to reported data, the pressures in the RPV and Containment Vessel have stabilised at approximately atmospheric pressure since 22 March. Unless further changes are observed, graphics will no longer be presented. About 56 tonnes of fresh water was injected into the Spent Fuel Pool of Unit 2 via the Fuel Pool Cooling & Clean-up Line from 04:09 till 05:45 UTC May 10. (Hydrazine was also injected from 04:19 till 05:35 UTC May 10.) The work to block the trench pit was started on 1 May, 04:35 UTC. Status of Unit 3 In addition to injection of fresh water into the RPV using the pipe of the Fire Extinguishing Line, at a rate of about 9.0 m3/h, injection of water was also started using the pipe of the Feedwater System at a rate of about 6 m3/h as of 02:00 UTC 16 May. The temperature at the RPV was 137.5oC at the feed water nozzle and 129.5oC at the lower head as of 20:00 UTC on 16 May. TEPCO has confirmed that boric acid was injected with the fresh water into the RPV, from 05:33 to 08:00 UTC on 15 May, as a precautionary measure to preclude a criticality condition. It is also considering boric acid addition for Units 1 and 2 however this is still under review. Status of Unit 4 About 100 tonnes of fresh water was sprayed over the Spent Fuel Pool of Unit 4 using a Concrete Pump Truck (62m class) from 07:25 till 11:25 UTC 15 May. In addition, 0.3 m3 hydrazine was also injected (from 07:26 till 09:30 UTC 15 May) Status of Units 5 and 6 Both units remain in cold shutdown with plant systems operating on off-site AC power. The reactor water temperatures were 46.9 oC for Unit 5, 28.2 oC for Unit 6, and were at approximately atmospheric pressure as of 21:00 UTC on 16 May. Beginning 01 May, accumulated water is being transferred from the basement of the turbine building of Unit 6 to a temporary tank. The batch transfer of 60 to 120 m3 happens almost daily and takes between 3 and 6 hours. The last reported transfer was on 16 May. In addition, from 02:00 to 03:30 on 10 through 12 May, accumulated water in basement of the reactor building of Unit 6 was transferred to the building of the Radioactive Waste Treatment Facilities of the same Unit.
Management of on-site contamination Contaminated soil On 25 April TEPCO commenced a programme of spraying the soil at the Fukushima Daiichi site with an anti-scattering agent to prevent the spread of radioactivity. The anti-scattering agent, a synthetic resin that binds the soil and reduces the resuspension of dust particles, is being spread remotely using a dumper truck. Prior to implementing the spraying, a programme of testing was carried out around the Common Spent Fuel Pool and Radioactive Waste Treatment Facilities. As of 04:30 UTC April 26 full scale implementation of spraying the soil at the Fukushima Daiichi site with an anti-scattering agent to prevent the spread of radioactivity started using two spraying methods: • by workers mainly in the mountain side of the facility • by unmanned crawler dump truck in the contaminated areas. Work is expected to continue for several weeks. Contaminated water TEPCO has planned and taken measures for preventing spread of contaminated water, as reported in the 25 April NISA evaluation of the report submitted by TEPCO regarding the discharge of water to the sea.
Radiation Monitoring of the Environment Fukushima Daiichi on-site monitoring Dose rate data Since 01 April, dose rates at all monitoring points around the Fukushima Daiichi site have been provided by NISA. The Dose rate measurements have been taken every 10 minutes. Dose rate data for the on-site monitoring stations at the Fukushima Daiichi site from 15 April is shown on the graph below (Fig 1). The highest dose rates are observed at MP7 and MP8 while the lowest dose rates are observed at MP1. Dose rates at all locations have shown a continuing downward trend since 15 April.
FIG.1 Onsite dose rate measurements (µSv/h) in Fukushima Daiichi from 15 April to 18 May 2011 05:00 UTC
Dose rate measurements for Fukushima Daiichi from 15 March to 14 April are available in previous status reports. On 8 May, 11:08 UTC the duct penetrating the double-entry doors in the reactor building of Unit 1 was cut and partially opened. On 8 May 19:17 UTC the double entry doors were opened. On 8 May, 20:10 UTC, positive pressure housing for Unit 1 was dismantled. The measurements done from 8 May 11:00 UTC up to 13 May 05:00 UTC at MP1 to MP8 and West Gate show no influence of the work carried out at Unit 1.
Radioactivity concentration in air samples Air sampling and dose rate data are available from the sampling point at the West Gate of the Fukushima Daiichi site from 29 March onwards. The sampling protocol measures separately the volatile and particulate fractions of radioactive iodine and caesium. The activity concentrations for I-131 and Cs-137 in air, from 29 March, are presented in Figure 2 below, together with the gamma dose rate values measured at the same sampling location over the same time period.
FIG.2 Dose rate and radioactivity concentration in air at the west gate of Fukushima Daiichi from 29 March until 17 May. Food Monitoring Food monitoring data were reported by the Japanese Ministry of Health, Labour and Welfare on 16 and 17 May for a total of 95 samples collected from 11-17 May from fourteen prefectures (Chiba, Fukushima, Gunma, Hyogo, Ibaraki, Kanagawa, Nagano, Niigata, Saitama, Shizuoka, Tochigi, Tokyo, Yamagata and Yamanashi). Analytical results for 93 of the 95 samples for various vegetables, shiitake mushrooms, fruit (cherry, grape and strawberry), raw unprocessed tea leaves and tea, dairy products (raw unprocessed milk and yoghurt), poultry eggs, various meats (pork and beef), fish and seafood, and seaweed indicated that I-131, Cs-134 and Cs-137 were either not detected or were below the regulation values set by the Japanese authorities. Two samples of unprocessed tea leaves taken in Ibaraki prefecture on 14 and 15 May were above the regulation values set by the Japanese authorities for Cs-134/Cs-137.
Food Restrictions No changes in food restrictions were reported since the last IEC Status Report of May 16. For more information on food restrictions, see website of the Japanese Ministry of Health, Labour and Welfare (http://www.mhlw.go.jp/english/topics/2011eq/dl/Instructions0516.pdf). Radioactivity in drinking water As of 10 May, the restriction of consumption of drinking water was lifted for infants’ in Iitate village, Fukushima prefecture. Based on the measurements reported 94 tap water samples on May 17, no radioactivity of Fukushima NPP origin was measured in 46 Prefectures. A low concentration (0,39 Bq/l ) of 137 Cs was measured in Tochigi Prefecture, resulting in no samples exceeded the reference values and consequently no change in the restrictions.
Environmental Data 1. Wind direction and wind speed (Persisting & prediction) Date 19 May 2011 20th May 2011 th
Day Thursday Friday
Plume behaviour on 19/05/2011 at 10:00 hrs
Source: http://www.weatheronline.co.uk
Wind direction SSW SSW
Wind speed (mph) 12 7
Updated Environmental monitoring data from ESLs
Sampling Sites Tarapur Narora Jaduguda Chattarpur Hyderabad Mumbai
Date of collection 16/5/11 16/5/11 16/5/11 16/5/11 16/5/11 16/5/11
Air (Bq.m-3) I-131 Cs-137 < 0.002 < 0.002 < 0.002 < 0.002 < 0.002 < 0.002 < 0.002 < 0.002 < 0.002 < 0.002 < 0.002 < 0.002
Water (Bq.l-1) I-131 Cs-137 < 0.1 < 0.1 < 0.1 < 0.1 < 0.1 < 0.1 < 0.1 < 0.1 < 0.1 < 0.1 < 0.1 < 0.1
No detectable activity was observed in any of the locations.
Vegetables (Bq.kg-1 fresh wt.) I-131 Cs-137 < 0.3 < 0.3 < 0.3 < 0.3 < 0.3 < 0.3 < 0.3 < 0.3 < 0.3 < 0.3 < 0.3 < 0.3
TEPCO prepared an environmental impact assessment on the release, which was independently verified. The assessment concluded that the predicted maximum exposure is sufficiently low compared to 1 mSv, the dose limit for the public.
Status of Unit 2 Injection of fresh water into the RPV was on-going, at a rate of about 7.0 m3/h, as reported at 20:00 UTC on 16 May. The temperature of the RPV at the feed water nozzle was 113.5ºC at 20:00 UTC on 16 May. According to reported data, the pressures in the RPV and Containment Vessel have stabilised at approximately atmospheric pressure since 22 March. Unless further changes are observed, graphics will no longer be presented. About 56 tonnes of fresh water was injected into the Spent Fuel Pool of Unit 2 via the Fuel Pool Cooling & Clean-up Line from 04:09 till 05:45 UTC May 10. (Hydrazine was also injected from 04:19 till 05:35 UTC May 10.) The work to block the trench pit was started on 1 May, 04:35 UTC. Status of Unit 3 In addition to injection of fresh water into the RPV using the pipe of the Fire Extinguishing Line, at a rate of about 9.0 m3/h, injection of water was also started using the pipe of the Feedwater System at a rate of about 6 m3/h as of 02:00 UTC 16 May. The temperature at the RPV was 137.5oC at the feed water nozzle and 129.5oC at the lower head as of 20:00 UTC on 16 May. TEPCO has confirmed that boric acid was injected with the fresh water into the RPV, from 05:33 to 08:00 UTC on 15 May, as a precautionary measure to preclude a criticality condition. It is also considering boric acid addition for Units 1 and 2 however this is still under review. Status of Unit 4 About 100 tonnes of fresh water was sprayed over the Spent Fuel Pool of Unit 4 using a Concrete Pump Truck (62m class) from 07:25 till 11:25 UTC 15 May. In addition, 0.3 m3 hydrazine was also injected (from 07:26 till 09:30 UTC 15 May) Status of Units 5 and 6 Both units remain in cold shutdown with plant systems operating on off-site AC power. The reactor water temperatures were 46.9 oC for Unit 5, 28.2 oC for Unit 6, and were at approximately atmospheric pressure as of 21:00 UTC on 16 May. Beginning 01 May, accumulated water is being transferred from the basement of the turbine building of Unit 6 to a temporary tank. The batch transfer of 60 to 120 m3 happens almost daily and takes between 3 and 6 hours. The last reported transfer was on 16 May. In addition, from 02:00 to 03:30 on 10 through 12 May, accumulated water in basement of the reactor building of Unit 6 was transferred to the building of the Radioactive Waste Treatment Facilities of the same Unit.
Management of on-site contamination Contaminated soil On 25 April TEPCO commenced a programme of spraying the soil at the Fukushima Daiichi site with an anti-scattering agent to prevent the spread of radioactivity. The anti-scattering agent, a synthetic resin that binds the soil and reduces the resuspension of dust particles, is being spread remotely using a dumper truck. Prior to implementing the spraying, a programme of testing was carried out around the Common Spent Fuel Pool and Radioactive Waste Treatment Facilities. As of 04:30 UTC April 26 full scale implementation of spraying the soil at the Fukushima Daiichi site with an anti-scattering agent to prevent the spread of radioactivity started using two spraying methods: • by workers mainly in the mountain side of the facility • by unmanned crawler dump truck in the contaminated areas. Work is expected to continue for several weeks. Contaminated water TEPCO has planned and taken measures for preventing spread of contaminated water, as reported in the 25 April NISA evaluation of the report submitted by TEPCO regarding the discharge of water to the sea.
Radiation Monitoring of the Environment Fukushima Daiichi on-site monitoring Dose rate data Since 01 April, dose rates at all monitoring points around the Fukushima Daiichi site have been provided by NISA. The Dose rate measurements have been taken every 10 minutes. Dose rate data for the on-site monitoring stations at the Fukushima Daiichi site from 15 April is shown on the graph below (Fig 1). The highest dose rates are observed at MP7 and MP8 while the lowest dose rates are observed at MP1. Dose rates at all locations have shown a continuing downward trend since 15 April.
FIG.1 Onsite dose rate measurements (µSv/h) in Fukushima Daiichi from 15 April to 18 May 2011 05:00 UTC
Dose rate measurements for Fukushima Daiichi from 15 March to 14 April are available in previous status reports. On 8 May, 11:08 UTC the duct penetrating the double-entry doors in the reactor building of Unit 1 was cut and partially opened. On 8 May 19:17 UTC the double entry doors were opened. On 8 May, 20:10 UTC, positive pressure housing for Unit 1 was dismantled. The measurements done from 8 May 11:00 UTC up to 13 May 05:00 UTC at MP1 to MP8 and West Gate show no influence of the work carried out at Unit 1.
Radioactivity concentration in air samples Air sampling and dose rate data are available from the sampling point at the West Gate of the Fukushima Daiichi site from 29 March onwards. The sampling protocol measures separately the volatile and particulate fractions of radioactive iodine and caesium. The activity concentrations for I-131 and Cs-137 in air, from 29 March, are presented in Figure 2 below, together with the gamma dose rate values measured at the same sampling location over the same time period.
FIG.2 Dose rate and radioactivity concentration in air at the west gate of Fukushima Daiichi from 29 March until 17 May. Food Monitoring Food monitoring data were reported by the Japanese Ministry of Health, Labour and Welfare on 16 and 17 May for a total of 95 samples collected from 11-17 May from fourteen prefectures (Chiba, Fukushima, Gunma, Hyogo, Ibaraki, Kanagawa, Nagano, Niigata, Saitama, Shizuoka, Tochigi, Tokyo, Yamagata and Yamanashi). Analytical results for 93 of the 95 samples for various vegetables, shiitake mushrooms, fruit (cherry, grape and strawberry), raw unprocessed tea leaves and tea, dairy products (raw unprocessed milk and yoghurt), poultry eggs, various meats (pork and beef), fish and seafood, and seaweed indicated that I-131, Cs-134 and Cs-137 were either not detected or were below the regulation values set by the Japanese authorities. Two samples of unprocessed tea leaves taken in Ibaraki prefecture on 14 and 15 May were above the regulation values set by the Japanese authorities for Cs-134/Cs-137.
Food Restrictions No changes in food restrictions were reported since the last IEC Status Report of May 16. For more information on food restrictions, see website of the Japanese Ministry of Health, Labour and Welfare (http://www.mhlw.go.jp/english/topics/2011eq/dl/Instructions0516.pdf). Radioactivity in drinking water As of 10 May, the restriction of consumption of drinking water was lifted for infants’ in Iitate village, Fukushima prefecture. Based on the measurements reported 94 tap water samples on May 17, no radioactivity of Fukushima NPP origin was measured in 46 Prefectures. A low concentration (0,39 Bq/l ) of 137 Cs was measured in Tochigi Prefecture, resulting in no samples exceeded the reference values and consequently no change in the restrictions.
Environmental Data 1. Wind direction and wind speed (Persisting & prediction) Date 19 May 2011 20th May 2011 th
Day Thursday Friday
Plume behaviour on 19/05/2011 at 10:00 hrs
Source: http://www.weatheronline.co.uk
Wind direction SSW SSW
Wind speed (mph) 12 7
Updated Environmental monitoring data from ESLs
Sampling Sites Tarapur Narora Jaduguda Chattarpur Hyderabad Mumbai
Date of collection 16/5/11 16/5/11 16/5/11 16/5/11 16/5/11 16/5/11
Air (Bq.m-3) I-131 Cs-137 < 0.002 < 0.002 < 0.002 < 0.002 < 0.002 < 0.002 < 0.002 < 0.002 < 0.002 < 0.002 < 0.002 < 0.002
Water (Bq.l-1) I-131 Cs-137 < 0.1 < 0.1 < 0.1 < 0.1 < 0.1 < 0.1 < 0.1 < 0.1 < 0.1 < 0.1 < 0.1 < 0.1
No detectable activity was observed in any of the locations.
Vegetables (Bq.kg-1 fresh wt.) I-131 Cs-137 < 0.3 < 0.3 < 0.3 < 0.3 < 0.3 < 0.3 < 0.3 < 0.3 < 0.3 < 0.3 < 0.3 < 0.3
