IAEA Briefing on Fukushima Nuclear Accident (31 March 2011, 14:00 UTC)

[OKIsItJustMe]

http://www.iaea.org/newscenter/news/tsunamiupdate01.html

Fukushima Nuclear Accident Update Log

Updates of 31 March 2011

Staff Report

IAEA Briefing on Fukushima Nuclear Accident (31 March 2011, 14:00 UTC)

Presentations:
→ IAEA Briefing on Fukushima Nuclear Accident, 30 March 2011
→ Summary of Reactor Status, 30 March 2011
→ Fukushima Radiological Monitoring and Consequences - Update, 30 March 2011
→ Fukushima Contaminated Water Flow Illustration, 30 March 2011
→ Fukushima Impact on Marine Environment, 30 March 2011
→ Fukushima Nuclear Power Plant Photos, 29 March 2011
→ Watch Video

1.Current Situation

Overall at the Fukushima Daiichi plant, the situation remains very serious.

The Unit 1 condenser is full. Pumping water from the Unit-1 turbine building basement to the Unit-1 condenser has been stopped as of 22:30 UTC on 28 March. For Units 2 and 3, in order to prepare for removal of the water from the turbine building basement, pumping of water from the condenser to the suppression pool water surge tank started at 07:45 UTC 29 March and 08:40 UTC March 28 respectively.

For Unit 1 fresh water has been continuously injected into the Reactor Pressure Vessel (RPV) through the feed-water line at an indicated flow rate of 8 m3/h using a temporary electric pump with diesel backup. In Unit 2 fresh water is injected continuously through the fire extinguisher line at an indicated rate of 8 m3/h using a temporary electric pump with diesel backup. In Unit 3 fresh water is being injected continuously at about 7 m3/h into the reactor core through the fire extinguisher line using a temporary electric pump with diesel backup.

The indicated temperature at the feed water nozzle of the RPV on Unit 1 has decreased from 281 °C to 251 °C and at the bottom of RPV decreased from 134 °C to 128 °C. There appears to be a corresponding decrease in RPV pressure with a slight decrease in Drywell pressure. The indicated temperature at the feed water nozzle of the RPV of Unit 2 has increased from 177 °C to 181 °C. The temperature at the bottom of RPV was not reported. Indicated Drywell pressure remains at atmospheric pressure. The indicated temperature at the feed water nozzle of the RPV in Unit 3 is about 89 °C and at the bottom of RPV is about 114 °C. The validity of the RPV temperature measurement at the feed water nozzle is still under investigation.

No further information is available regarding the plan to commence the pumping of water into the Unit 1 Spent Fuel Pool by concrete pumping truck from 29 March. On Unit 2 the temporary electric pump supplying water to the spent fuel pool experienced a malfunction. Spent fuel pool water supply was changed to a fire truck pump but a crack was discovered in a hose on 30 March 04:10 UTC. Pumping water to the spent fuel pool was therefore stopped. Pumping was subsequently restored and water was fed into spent fuel pool in Unit 2 from 10:05 UTC on March 30. Water injection into the spent fuel pool in Unit 4 by concrete pump was completed at 09:33 UTC on March 30.

Units 5 and 6 remain in cold shutdown

2. Radiation Monitoring

On 30 March, deposition of iodine-131 was detected in 8 prefectures, and deposition of cesium-137 in 12 prefectures. On 30 March in the prefectures where deposition of iodine-131 was reported, the range was from 2.5 to 240 becquerel per square metre. For caesium-137, the range was from 3 to 57 becquerel per square metre. In the Shinjyuku district of Tokyo, the daily deposition of both iodine-131 and cesium-137 on 30 March was below 30 becquerel per square metre. No significant changes were reported in the 45 prefectures in gamma dose rates compared to yesterday.

Most of the previously imposed recommendations for restrictions on drinking have been lifted. As of 28 March, recommendations for restrictions based on I-131 concentration remain in place in four villages of in the Fukushima prefecture, in three of these villages, restrictions continue to apply for infants only.

Two IAEA teams are currently monitoring radiation levels and radioactivity in the environment in Japan. On 30 March, one team made gamma dose-rate measurements in the Tokyo region at 7 locations. Gamma-dose rates measured ranged from 0.03 to 0.28 microsievert per hour, which is within or slightly above the background. The second team made additional measurements at 7 locations in the Hirono area, South of Fukushima-Daiichi NPP. The measurement locations were at distances of 23 to 39 km from the Fukushima nuclear power plant. The dose rates ranged from 0.5 to 4.9 microsievert per hour. At the same locations, results of beta-gamma contamination measurements ranged from 0.04 to 0.34 Megabecquerel per square metre.

Since our briefing of yesterday, significant data related to food contamination has been submitted by the Japanese Ministry of Health, Labour and Welfare. Seventy-six samples were taken from 28-30 March, and reported on 30 March. Analytical results for 51 of the 76 samples for various vegetables, fruit (strawberry), seafood (sardines), and unprocessed raw milk in eight prefectures (Chiba, Fukushima, Gunma, Ibaraki, Kanagawa, Niigata, Saitama, and Yamagata), indicated that iodine-131, caesium-134 and caesium-137 were either not detected or were below the regulation values set by the Japanese authorities. However, it was reported that analytical results in Fukushima prefecture for the remaining 25 of the 76 samples for broccoli, cabbage, rapeseed, spinach and other leafy vegetables, indicated that iodine-131 and/or caesium-134 and caesium-137 exceeded the regulation values set by the Japanese authorities.

The Joint FAO/IAEA Food Safety Assessment Team met with local government officials in Gunma prefecture on Wednesday. Farmers and producers were also represented and the meeting attracted media coverage. The questions to the IAEA/FAO team mainly focused on technical issues of remediation strategies, including the implications of long term releases if the NPP is not stabilized, the disposal of contaminated produce, mechanisms of 131I and 137Cs contamination, other possible radionuclides that may be produced/should be monitored, contamination of fruit and mushrooms, occupational exposure risks in the handling animals and agricultural products, feeding strategies for animals in affected areas, monitoring of soil and fallout and remediation strategies and methodologies. There were also discussions with producers and farmer organizations over the development of strategies for the next cropping season.

Local government officials briefed the FAO/IAEA Team on current knowledge of the extent of contamination in Gunma prefecture, including the principal agricultural products affected and levels of contamination found.

The Joint FAO/IAEA Team presented their report and responded to inquires at a follow-up inter-ministerial meeting in Tokyo. The meeting was attended by representatives of the Japanese Cabinet Office, Ministry of Foreign Affairs, Ministry of Health, Labour and Welfare and the Ministry of Agriculture. Strong interest was expressed as to the remediation of the agricultural land, continued possible contamination of agricultural products, and the need to maintain communication with relevant ministries in the future.

New results from the marine monitoring stations 30 km off-shore were reported for 28 March. These results indicate a decrease for the northernmost sampling station for I-131 and a slight increase for Cs-137 as compared to values measured on 27 March. For sampling points situated towards the south of the transect an increase has been recorded, both for I-131 and for Cs-137 as compared to the previous day, with maximum concentrations in water below 30 Bq/l and 20 Bq/l respectively, still considerably lower than the maxima recorded on 23 March. This increase can be correlated with trends in concentrations measured close to the discharge points.

The latest analyses in seawater 330 m south of the discharge point of NPP Units 1-4, and 30 m north of the discharge point of Units 5-6 were made available for 29 March. In particular readings of 130 000 Bq/l of I-131, 32 000 Bq/l of Cs-137 and 31 000 Bq/l of Cs-134 were reported near Units 1 - 4.

The Russian Federation, Singapore, Ireland and Switzerland reported the detection of very small amounts of iodine-131 and cesium-137 in air. Highest levels found are in the order of a few millibecquerel per cubic meter. The levels are not of any radiological concern.

IAEA Briefing on Fukushima Nuclear Accident (30 March 2011, 16.30 UTC)

Presentations:

→ IAEA Briefing on Fukushima Nuclear Accident, 30 March 2011
→ Summary of Reactor Status, 30 March 2011
→ Fukushima Radiological Monitoring and Consequences - Update, 30 March 2011
→ Fukushima Contaminated Water Flow Illustration, 30 March 2011
→ Fukushima Impact on Marine Environment, 30 March 2011
→ Fukushima Nuclear Power Plant Photos, 29 March 2011
→ Watch Video

On Wednesday, 30 March 2011, the IAEA provided the following information on the current status of nuclear safety in Japan.

1. Current Situation

Overall at the Fukushima Daiichi plant, the situation remains very serious.

With respect to the water that is present in the turbine buildings. In Unit 1, water has continued to be pumped into the condenser with 3 pumps (6.5 ton/hour each) and the water level has reduced from 40cm to 20cm. In Unit 2 from 07.45 UTC, pumping of water from the Condensate Storage Tank into the Surge Tank was started so that the that condenser can be drained to the Condensate Storage Tank and contaminated water can be pumped out from the Turbine building into the condenser. The same process of pumping the water from the Condensed Water Storage Tank into the Surge Tank was started on Unit 3 at 08.40 UTC on 28 March.

Near the Unit 3 building, 3 workers spilled water over themselves when removing a flange from seawater pipes on the residual heat removal system (RHR). After showering, contamination was not detected.

Fresh water has been continuously injected into the Reactor Pressure Vessel (RPV) through feed-water line at an indicated flow rate of 8.0 m3/h at Unit 1. The pumping of freshwater into the RPV has been switched from fire trucks to temporary electrical pumps with diesel generator. At Units 2 and 3 fresh water is being injected continuously through the fire extinguisher line at an indicated rate of 7 m3/h using a temporary electric pump.

The indicated temperature at the feed water nozzle of the RPV of Unit 1 has decreased from 323 °C to 281 °C and at the bottom of RPV remained stable at 134 °C. There is a corresponding decrease in Drywell pressure. At Unit 2 the indicated temperature at the feed water nozzle of the RPV has increased from 154 °C to 177 °C and at the bottom of RPV has increased from 78 °C to 88 °C. Indicated Drywell pressure remains at atmospheric pressure. For Unit 3 the indicated temperature at the feed water nozzle of the RPV is about 75 °C and at the bottom of RPV is about 116 °C. The validity of the RPV temperature measurement at the feed water nozzle is still under investigation.

With respect to the Spent Fuel Pools, it was planned to commence the pumping of water into the Unit 1 Spent Fuel Pool by concrete pumping truck from 29 March. Also, on 29 March pumping of fresh water into the Unit 2 spent fuel pool commenced via a temporary electrical pump. The temperature of the spent fuel pool is 46 °C as of 19:00 UTC, 29 March. For Unit 4 it was planned to commence pumping freshwater into the spent fuel pool on March 29. The IAEA has not received information on implementation of spraying activities in units 1 and 4.

Units 5 and 6 remain in cold shutdown

2. Radiation Monitoring

The majority of the recently measured radioactivity levels in drinking water are being reported below the levels established by the Japanese authorities which are 100 Bq/L of I-131 for infants; 300 Bq/L for adults and 200 Bq/L of Cs-137 for infants and adults. Previously imposed recommendations for restrictions on drinking water are being lifted in most of the affected locations. As of 28 March, recommendations for restrictions based on I-131 concentration remain in place in one village in the Fukushima prefecture. In three other locations of the Fukushima prefectures, restrictions continue to apply for infants only.

Two IAEA teams are currently monitoring radiation levels and radioactivity in the environment in Japan. On 29 March, one team made gamma dose-rate measurements in the Tokyo region at 8 locations. Gamma-dose rates measured ranged from 0.02 to 0.19 microsievert per hour, which is within or slightly above the background.

The second team made additional measurements at distances of 32 to 62 km, at directions North to Northwest from the Fukushima nuclear power plant. At these locations, the dose rates ranged from 0.5 to 6.8 microsievert per hour. At the same locations, results of beta-gamma contamination measurements ranged from 0.05 to 0.45 Megabecquerel per square metre.

Based on measurements of I-131 and Cs-137 in soil, sampled from 18 to 26 March in 9 municipalities at distances of 25 to 58 km from the Fukushima Nuclear Power Plant, the total deposition of iodine-131 and cesium-137 has been calculated. The results indicate a pronounced spatial variability of the total deposition of iodine-131 and cesium-137. The average total deposition determined at these locations for iodine-131 range from 0.2 to 25 Megabecquerel per square metre and for cesium-137 from 0.02-3.7 Megabecquerel per square metre. The highest values were found in a relatively small area in the Northwest from the Fukushima Nuclear Power Plant. First assessment indicates that one of the IAEA operational criteria for evacuation is exceeded in Iitate village. We advised the counterpart to carefully assess the situation. They indicated that they are already assessing.

As far as food contamination is concerned, 35 samples taken from 25-29 March, and reported on 29 March, for various vegetables, fruit (strawberry), seafood, pork and unprocessed raw milk in nine prefectures (Chiba, Gunma, Ibaraki, Kanagawa, Nagano, Niigata, Saitama, Tochigi and Yamagata), stated that results for iodine-131, caesium-134 and caesium-137 were either not detected or were below the regulation values set by the Japanese authorities.

The Joint FAO/IAEA Food Safety Assessment Team met with local government officials in Tochigi prefecture on 29 March and provided advice related to contamination of food and the environment.

Local government officials briefed the FAO/IAEA Team on the extent of contamination in Tochigi, the principle agricultural products affected, the main production areas and production methods (greenhouses, open-air), levels of contamination found (principally in air, tap/ground water and vegetables) and imminent plans to monitor soil contamination. A field visit also took place to a spinach producer outside Utsunomiya City.

Based on these latest discussions with the Tochigi authorities, it is apparent that the focus of the Joint FAO/IAEA mission has changed to some extent from the mechanisms of contamination to remediation strategies and techniques related to plant and animal production, food traceability and water/soil characterization.

The FAO/IAEA team is also meeting with the local government officials in Gunma prefecture today.

No new results from the marine monitoring stations 30 km off-shore as well as from close to the discharge, were reported since 27 March.

One IAEA staff member of the Monaco marine laboratory will fly to Japan on 31 March in order to join the Japanese team assessing marine environment.

The IAEA continues activities under the Joint Radiation Emergency Management Plan of the International Organisations through regular video/teleconferences. As of 30 March the WHO liaison officer is working in the IEC.

In response to the request for data on measurement, the IEC has received information from Singapore. The Singapore Authorities have sent reports on measurements in food imported from Japan (cabbages). Some samples were over the Codex Alimentarius values recommended for international trade. In Singapore no increase in gamma dose rates have been observed and no fission products have been found in air samples.

[FBaggins]

1. Well...now THAT can't be true.

"On 30 March, deposition of iodine-131 was detected in 8 prefectures, and deposition of cesium-137 in 12 prefectures. On 30 March in the prefectures where deposition of iodine-131 was reported, the range was from 2.5 to 240 becquerel per square metre. For caesium-137, the range was from 3 to 57 becquerel per square metre. In the Shinjyuku district of Tokyo, the daily deposition of both iodine-131 and cesium-137 on 30 March was below 30 becquerel per square metre. No significant changes were reported in the 45 prefectures in gamma dose rates compared to yesterday."

Why... I have it on good authority that the rates were up to 900 Bq/sq meter and rising. That CS rates were twice that of the hot spots near Chernobyl... but here they say 3-57 Bq/sq M?

So this report must be bogus. :)

On edit... whoops... it's worse than that. The claim was that the levels were 55 MBq. So the claim was actually 1,000 times higher.

[OKIsItJustMe]

2. Correction

…Correction: A previous version of this update mistakenly reported that Singapore has reported to the IAEA that it had detected very small amounts of iodine-131 and cesium-137 in air. Singapore has not made such a report.