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IAEA Fukushima Daiichi Status Report

Full Update

Chronology of Updates:
10 November | 4 November | 2 November | 27 October | Full Update

Fukushima

The IAEA International Remediation Expert Mission examines Reactor Unit 3 during the team's visit to TEPCO's Fukushima Dai-ichi Nuclear Power plant, 11 October 2011. (Photo: G. Verlini/IAEA)

The IAEA issues regular Status Reports to the public on the current status of the Fukushima Daiichi Nuclear Power Plant, including information on environmental radiation monitoring, the status of workers and current conditions on-site at the plant.

The information cited in this Report is compiled from official Japanese sources, including the Ministry of Economy, Trade and Industry (METI), the Nuclear and Industrial Safety Agency (NISA), the Ministry of Education, Culture, Sports, Science and Technology (MEXT), the Ministry of Land, Infrastructure, Transport and Tourism (MLIT), the Ministry of Health, Labour and Welfare (MHLW) and the Ministry of Foreign Affairs (MOFA) through the Japanese Permanent Mission in Vienna and the Cabinet's Office of the Prime Minister. Information is also provided by the Tokyo Electric Power Company (TEPCO), the operator of the Fukushima Daiichi Nuclear Power Plant.

Questions on the information provided in this report may be directed to [email protected].

IAEA Fukushima Daiichi Status Report (10 November 2011)


What are the recent developments at the Fukushima Daiichi Nuclear Power Plant?

On 5 November TEPCO reported details of its removal of obstacles to robots surveying the Unit 3 Reactor Building. Removing these obstacles has allowed for greater access to areas on the first floor and subsequently enabled more detailed surveys of dose rates and environmental conditions (e.g. temperatures) that can be conducted via robotic survey.

TEPCO is working to desalinate radioactive water that has accumulated as a result of efforts to cool the reactors and spent fuel pools with seawater. Desalination of the water reduces the potential for corrosion caused by salt. On 5 November TEPCO released a detailed document outlining its capability to desalinate water onsite. This document outlines the operation of reverse osmosis desalinisation facilities and their evaporative concentration capabilities. Included are a number of figures showing salt concentration over time at the outlet and inlet to the system. A video explaining the water treatment process for salt removal has also been posted online.

On 6 November TEPCO released details of a new water treatment system intended to remove contamination from the Spent Fuel Pool of Unit 2. Due to the limited space around that pool, the system will be installed on two trucks parked nearby. Details of the latest reported values of the radioactive material concentration in each Spent Fuel Pool are available. On 7 November TEPCO released new results for the current decontamination efforts of its onsite accumulated water treatment process.

The process of removal of contaminated rubble using remote controlled heavy machinery is on-going.

Table 1: Status of Cooling Water Flow, Temperatures and Pressure at Units 1, 2 and 3

TEPCO's Fukushima Daiichi Nuclear Power Plant station reactors 1, 2 and 3 require circulating water to remove heat from their fuel.

Plant operators are working to bring the reactors into a "cold shutdown condition" defined by TEPCO and the Nuclear Emergency Response Headquarters as:

  1. Lowering the coolant water temperature to below 100 degrees centigrade while reducing the pressure inside the reactor vessels to the same as the outside air pressure, or 1 atmosphere (atm); and
  2. Bringing release of radioactive materials from primary containment vessel under control and reducing public radiation exposure by additional release (not to exceed 1 mSv/year at the site boundary as a target).
Indications Measurement Reactor
Unit 1 Unit 2 Unit 3
Water Flow Into Reactor1 Litres/hour 7 800 10 200 10 800
Reactor Vessel Pressure atm 1.11 1.07 Downscale
Outer Containment Vessel Pressure2 atm 1.21 1.15 1.02
Reactor Vessel Temperature (Feed Water Nozzle)3 °C 40.8 67.8 61.8
Reactor Vessel Temperature (At Bottom of Reactor)4 °C 43.8 71.4 70.7
Suppression Pool Pressure5 atm 0.84 Below Scale6 1.87
Date/Time of Data Acquisition   9 November
12:00 UTC
9 November
12:00 UTC
9 November
12:00 UTC
Notes:

1 Plant operators are pumping water into Unit 1 through one injection point and through two injections points in Units 2 and 3.
2 The containment vessel completely surrounds the reactor vessel and support systems. It is designed to prevent the release of radioactive materials following an accident. Japanese plant operators are working to reduce the pressure in the containment vessel to 1 atmosphere, the same as the outside air pressure.
3 The temperature of the coolant water as it is pumped into the reactor vessels.
4 The temperature of the coolant water, measured at the bottom of the reactor vessel.
5 The suppression pool is designed to limit pressure in the containment vessel during an accident by condensing steam from the containment vessel. Japanese workers are aiming to get this pressure down to 1 atmosphere.
6 "Below scale" means the reading is below the lowest indication the instrument is capable of detecting. This is typically an indication that an instrument has somehow failed.

Table 2: Most Recently Reported Temperatures in Fukushima Daiichi Spent Fuel Pools

Spent fuel removed from a nuclear reactor is highly radioactive and generates intense heat. Nuclear plant operators typically store this material in pools of water that cool the fuel and shield the radioactivity. Water in a spent fuel pool is continuously cooled to remove heat produced by spent fuel assemblies.

According to IAEA experts, a typical spent fuel pool temperature is kept below 25 °C under normal operating conditions. The temperature of a spent fuel pool is maintained by constant cooling, which requires a constant power source.


Location
Water Temperature
Temperature °C Date Measured
Unit 1 22.0 9 November
Unit 2 24.9 9 November
Unit 3 22.6 9 November
Unit 4 31.0 9 November
Unit 5 24.1 9 November
Unit 6 24.0 9 November
Common Spent Fuel Pool 25.0 9 November

What is the latest information regarding radiation monitoring of foodstuffs?

Food monitoring data were reported from 2 to 8 November by the Ministry of Health, Labour and Welfare (MHLW) for a total of 3585 samples collected on 23 and 30 April, 3 May, 17 and 19 August, 8, 12-14 and 26-28 September, 2, 6-7, 8, 10-11, 13-14 and 17-31 October and 1-8 November in 32 different prefectures (Aichi, Akita, Aomori, Chiba, Ehime, Fukui, Fukushima, Gifu, Gunma, Hokkaido, Hyogo, Ibaraki, Iwate, Kagoshima, Kanagawa, Kyoto, Mie, Miyagi, Miyazaki, Nagano, Nagasaki, Niigata, Okayama, Saitama, Shimane, Shizuoka, Tochigi, Tokushima, Tokyo, Tottori, Yamagata, Yamanashi).

These data included samples of various vegetables, fruit and fruit products, mushrooms, nuts, cereals, dairy products, baby food, tea leaves, meat, eggs, honey, fish and seafood.

Analytical results for 3 555 (over 99%) of the 3 585 samples indicated that Cs-134 and Cs-137 or I-131 were either not detected or were below the regulation values set by the Japanese authorities. However, 30 samples were above the regulation values for radioactive caesium (Cs-134 and Cs-137), as follows:

  • As reported on 2 November, seven samples of fish collected on 25 and 31 October in Fukushima prefecture, three samples of mushrooms collected on 31 October and 1 November in Ibaraki and Tochigi prefectures, one sample of beef collected on 1 November in Miyagi prefecture and one sample of unrefined tea leaves collected on 28 October in Kanagawa prefecture.
  • As reported on 4 November, three samples of mushrooms collected on 2 November in Kanagawa and Tochigi prefectures.
  • As reported on 7 November, six samples of meat collected on 10, 27, 29 and 31 October from Fukushima prefecture and two samples of mushrooms collected on 4 November from Tochigi prefecture; and
  • As reported on 8 November, five samples of meat collected on 2, 17, 19, 22 and 25 October and one sample of persimmon collected on 4 November in Fukushima prefecture, and one sample of dried shiitake mushrooms (log-grown) collected on 7 November in Kanagawa prefecture.

Updated information on food restrictions were reported by MHLW on 7 November indicating that restrictions were lifted on the distribution and/or consumption of non-head type leafy vegetables and turnips produced in specific areas of Fukushima prefecture. Restrictions were implemented on the distribution of log-grown brick cap mushrooms (outdoor cultivation) in specific areas of Tochigi prefecture.

Additional information on food restrictions were also reported by the MHLW on 8 November indicating that restrictions were implemented on the distribution of log-grown brick cap mushrooms (outdoor cultivation) in additional areas of Tochigi prefecture.

A full list of instructions regarding food restrictions was provided by MHLW on 9 November.

IAEA Fukushima Daiichi Status Report (4 November 2011)


The IAEA has received new information regarding the detection of xenon-133 and xenon-135 gases on 1 November inside the Primary Containment Vessel (PCV) of Fukushima Daiichi Unit 2.

Based on further analysis, Japanese authorities have concluded that the xenon concentrations are not due to a criticality event but rather from the spontaneous fission of curium-242 and 244. (Spontaneous fission is a form of radioactive decay that does not involve chain reactions and is characteristic of very heavy isotopes. Spontaneous fission occurs in low levels in all nuclear reactors.)

This conclusion is based on three key factors outlined and discussed in the report:

  • The inventory of Cu-242 and Cu-244 was calculated as was the concentration of Xe-135, resulting from the spontaneous fission of Cu-242 and Cu-244. If nuclear fission of the reactor's uranium fuel were occurring, at the lowest possible level, the levels of xenon detected would be several orders of magnitude higher than those measured. Current levels of xenon are consistent with those that would be generated by spontaneous fission of Cu-242 and Cu-244;
  • If the core had been experiencing a criticality event, the injection of boron water should have stopped the criticality and terminated the generation of xenon. However, the xenon levels were not influenced by injection of boron water into the core; and
  • If the core was undergoing a criticality event the temperature and pressure readings would be expected to rise as the event would increase heat production within the core. However, the temperature and pressure levels have not undergone any significant increases either before or after xenon were detected, indicating that no criticality event is occurring.

Presently the report detailing these findings is only available in Japanese. A link to the English version will be provided once it is made available.

IAEA Fukushima Daiichi Status Report (2 November 2011)


What are the recent developments at the Fukushima Daiichi Nuclear Power Plant?

On 1 November, TEPCO detected the possible presence of xenon-133 and xenon-135 gases sampled from inside the Primary Containment Vessel (PCV) of Fukushima Daiichi Unit 2. The presence of these short-lived radionuclides indicates that some nuclear fission may have recently occurred. TEPCO reported that no increases in radiation levels have been observed. According to TEPCO "even if a fission reaction is assumed to be on-going, its scale is extremely small and the reactor is in a stable condition as a whole."

TEPCO responded to this development by injecting 10 tonnes of boric acid solution (water containing 480 kg of boric acid) into the reactor from 02:48 to 03:47 local time on 2 November. Boric acid solution is used as a countermeasure to nuclear fission for its ability to absorb neutrons.

Further radionuclide analysis of the gas samples collected from Unit 2 is on-going and will be conducted in collaboration with the Japan Atomic Energy Agency (JAEA).

On 31 October, 10 tons of fresh water was added to the Spent Fuel Pool at Unit 4.

On 27 October, a crack was discovered on the casing for the axle junction of the ceiling crane located in the Common Spent Fuel Pool Building. Under normal operating conditions, the ceiling crane is used to move nuclear fuel elements and other items.

Roof Panel Installation, 14 October 2011 On 28 October, TEPCO announced that the cover for Unit 1 is now considered fully operational and functional. (See photo: Roof Panel Installation, 14 October 2011). The cover has been placed over Unit 1 to reduce the dispersion of radionuclides to the environment.

TEPCO has released a video that chronicles its construction and installation.

On 22 October TEPCO released an update of its efforts to manage onsite contaminated water. A video with a detailed discussion of the water treatment process has been made available online.

Table 1: Status of Cooling Water Flow, Temperatures and Pressure at Units 1, 2 and 3

TEPCO's Fukushima Daiichi Nuclear Power Plant station reactors 1, 2 and 3 require circulating water to remove heat from their fuel.

Plant operators are working to bring the reactors into a "cold shutdown condition" defined by TEPCO and the Nuclear Emergency Response Headquarters as:

  1. Lowering the coolant water temperature to below 100 degrees centigrade while reducing the pressure inside the reactor vessels to the same as the outside air pressure, or 1 atmosphere (atm); and
  2. Bringing release of radioactive materials from the primary containment vessel under control and reducing public radiation exposure by additional release (not to exceed 1 mSv/year at the site boundary as a target).
Indications Measurement Reactor
Unit 1 Unit 2 Unit 3
Water Flow Into Reactor1 Litres/hour 7 600 10 000 10 600
Reactor Vessel Pressure atm 1.14 1.08 Downscale
Outer Containment Vessel Pressure2 atm 1.24 1.13 1.02
Reactor Vessel Temperature (Feed Water Nozzle)3 °C 50.6 71.5 64.4
Reactor Vessel Temperature (At Bottom of Reactor)4 °C 53.8 76 70.5
Suppression Pool Pressure5 atm 0.9 Below Scale6 1.88
Date/Time of Data Acquisition   2 November
12:00 UTC
2 November
12:00 UTC
2 November
12:00 UTC
Notes:

1 Plant operators are pumping water into Unit 1 through one injection point and through two injections points in Units 2 and 3.
2 The containment vessel completely surrounds the reactor vessel and support systems. It is designed to prevent the release of radioactive materials following an accident. Japanese plant operators are working to reduce the pressure in the containment vessel to 1 atmosphere, the same as the outside air pressure.
3 The temperature of the coolant water as it is pumped into the reactor vessels.
4 The temperature of the coolant water, measured at the bottom of the reactor vessel.
5 The suppression pool is designed to limit pressure in the containment vessel during an accident by condensing steam from the containment vessel. Japanese workers are aiming to get this pressure down to 1 atmosphere.
6 "Below scale" means the reading is below the lowest indication the instrument is capable of detecting. This is typically an indication that an instrument has somehow failed.

Table 2: Most Recently Reported Temperatures in Fukushima Daiichi Spent Fuel Pools

Spent fuel removed from a nuclear reactor is highly radioactive and generates intense heat. Nuclear plant operators typically store this material in pools of water that cool the fuel and shield the radioactivity. Water in a spent fuel pool is continuously cooled to remove heat produced by spent fuel assemblies.

According to IAEA experts, a typical spent fuel pool temperature is kept below 25 °C under normal operating conditions. The temperature of a spent fuel pool is maintained by constant cooling, which requires a constant power source.


Location
Water Temperature
Temperature °C Date Measured
Unit 1 22.0 2 November
Unit 2 24.7 2 November
Unit 3 23.1 2 November
Unit 4 31.0 2 November
Unit 5 24.5 2 November
Unit 6 24.5 2 November
Common Spent Fuel Pool 25.0 1 November

What is the latest status regarding workers at Fukushima Daiichi?

TEPCO regularly releases summaries of the radiation exposure (both internal and external) results of its workers. (The following Table contains the latest results of combined external and internal radiation exposures to workers at Fukushima Daiichi released by TEPCO on 31 October). The figures demonstrate a decrease in the level of exposure to onsite workers over time from March through September.

As of March 15, the effective radiation dose limit for radiation workers at Fukushima Daiichi was raised from 100 mSv to 250 mSv, provided that they are under emergency situations.

Table 3: Combined External and Internal Radiation Doses to Workers at Fukushima Daiichi

Dose (mSv) March April May June July August September
Greater Than 250 6 0 0 0 0 0 0
200-250 2 0 0 0 0 0 0
150-200 13 0 0 0 0 0 0
100-150 77 0 0 0 0 0 0
50-100 309 3 0 0 0 0 0
20-50 859 81 19 16 6 0 7
10-20 1 041 310 133 96 69 21 28
Less Than 10 1 434 3 214 2 854 1 997 2 043 1 080 1 011
Total Personnel 3 742 3 608 3 017 2 111 2 118 1 101 1 046
Max (mSv) 670.36 69.28 41.61 39.62 31.24 18.27 30.81
Average (mSv) 22.58 3.83 2.85 2.26 1.85 1.46 1.80

On 17 October, a TEPCO employee was working with water injection equipment on the second floor of the reactor building for Unit 1. When his work was completed, contamination was discovered around his mouth. However, a whole body counter measurement identified no internal contamination.

TEPCO had previously reported that 65 personnel (all sub-contractors) who worked at the Fukushima Plant during the initial response had not undergone whole body counting. Several have been identified since that time and an investigation to identify remaining personnel is on-going. At present there are 20 persons outstanding from this identification process. Nine of them have been identified as not being applicable for whole body counting, seven are still under investigation to obtain their contact details and four have been unable to be found through their provided contact information.

On 29 October two workers were injured onsite. An accident occurred during the disassembly of a crane used to construct the Unit 1 reactor building cover. A bundle of wires fixed by the bank wire on the base released and struck workers engaged in dismantling work. One worker broke both of his legs and the other worker sustained injury to both his shoulders and other areas of his body. The worker with broken legs was transported via helicopter to the Fukushima Medical University Hospital immediately after the accident where he had surgery and was transferred to an Intensive Care Unit. The other worker was transported to the Sogo Iwaki Kyoritsu Hospital approximately 4 hours after first receiving treatment at the medical unit at J-Village. The cause of the accident is currently being investigated.

On 1 November TEPCO announced that due to the reduction of the airborne concentration of contamination onsite, requirements for wearing facemasks onsite are being reduced. These new rules come into effect on 8 November.

What is the current status of evacuation areas around the Fukushima Daiichi Plant?

Current Evacuation Areas Based on the Basic Approach for Reassessing Evacuation Areas the Nuclear Emergency Response Headquarters lifted the restriction of the "Evacuation Prepared Areas in Case of an Emergency". (See map: Current Evaluation Areas - Click on map to see an enlarged version).

The previous map of evacuation areas is available online.




What measures have been taken to assist residents in the areas around the Fukushima Daiichi Plant?

On 17 October METI released an updated version of the Roadmap for Immediate Actions for the Assistance of Residents Affected by the Nuclear Incident. The main updates added to the document include the following points:

  • On 30 September the Nuclear Emergency Response Headquarters lifted the designation of Evacuation Prepared Areas for Cases of Emergency;
  • Based on the request from the five municipalities previously designated as the Evacuation Prepared Areas in Case of Emergency, as part of the support to recover these areas, detailed monitoring mainly focusing on the roads necessary for living as well as well water and rivers is now under implementation;
  • "The Municipalities Reconstruction Support Team in response to the Nuclear Accident", now exchanging opinions with the affected municipalities;
  • Since 19 September a second round of temporary access via private vehicles has been on-going into the restricted areas;
  • 5 435 households (representing 12 448 people) have been allowed temporary access into the restricted areas, with 4 989 of the households allowed to access via private vehicle;
  • Meetings are now being held to explain "the Basic Policy for Emergency Decontamination Work" and "Act on Special Measures concerning Handling of Radioactive Pollution" in Fukushima Prefecture and neighbouring prefectures;
  • Experts have begun visiting municipalities to provide guidance and advice on decontamination;
  • A large scale thyroid examination has been started since 9 October for residents in Fukushima Prefecture at and under the age of 18 at the time of the accident (approx. 360 000 people);
  • Survey of the exposure dose to all the residents in Fukushima Prefecture (approx. 2 million people) is still on-going;
  • Since 26 August arrangements to protect 320 dogs and 190 cats have been made;
  • As of 11 October construction of 15 787 temporary housing units has started, with approximately 90% of those units having been completed;
  • As of 7 October 2073 households from Fukushima Prefecture have moved into new or assigned housing - nationwide 16 537 households have moved into new houses or been assigned housing (note: this figure also includes those displaced by the earthquake and tsunami);
  • As of 5 October, 126 cattle remain in the Deliberate Evacuation Area out of the approximately 9 300 heads subject to evacuation;
  • Fukushima Prefecture and the Ministry of Agriculture, Forestry and Fisheries were conducting decontamination tests on soil up to the end of August - based on the results from these tests on 14 September methods to decontaminate agricultural soil according to use, classification and concentrations of contaminants were released to the public;
  • On 30 September the Nuclear Emergency Response Headquarters officially released methods for the decontamination of agricultural soil based on the "Guidelines for Municipal Decontamination Work";
  • As of 1 October more than 220 000 people have been screened for contamination - no cases of adverse health effects have been discovered; and
  • Aircraft monitoring is scheduled to be conducted over the entirety of East Japan - it is expected to be complete by the end of 2011.

The updated document also includes information released on job creation activities, support to small- and medium sized businesses and financial assistance measures that have been and will continue to be given. A summary is also available online.

The IAEA will continue to issues regular status reports to the public on the current status of the Fukushima Daiichi Nuclear Power Plant.

Questions on the information provided in this report may be directed to [email protected].

IAEA Fukushima Daiichi Status Report (27 October 2011)


What information is included in these status reports?

The IAEA has been providing regular status updates to the competent authorities within its member states since the Fukushima accident occurred on 11 March 2011.

The IAEA now issues regular status reports to the public on the current status of the Fukushima Daiichi Nuclear Power Plant, including information on environmental radiation monitoring, the status of workers, and current conditions on-site at the plant.

The information cited in the status reports is compiled from official Japanese sources, including the Ministry of Education, Culture, Sports, Science and Technology (MEXT), the Ministry of Economy, Trade and Industry (METI), the Nuclear and Industrial Safety Agency (NISA), the Ministry of Land, Infrastructure, Transport and Tourism (MLIT), the Ministry of Health, Labour and Welfare (MHLW) and the Ministry of Foreign Affairs (MOFA) through the Japanese Permanent Mission in Vienna and the Cabinet's Office of the Prime Minister. Information is also provided by the Tokyo Electric Power Company (TEPCO), the operator of the Fukushima Daiichi Nuclear Power Plant.

Questions on the information provided in these reports may be directed to [email protected].

What is the situation regarding evacuation areas and protective measures for the public?

Measurements of gamma dose rates are being taken continuously at fixed reference locations in each Japanese prefecture. Since 13 March, the dose rates generally show a decreasing trend. The current rate of this decrease is small due to fact that short half-life radionuclides have decayed.

Japanese authorities have compiled data on the concentrations of radioactive caesium on the ground surface at roughly 2 200 locations within approximately 100 kilometers from the Fukushima Daiichi Nuclear Power Plant. These studies have been conducted by measuring air dose rates and collecting soil samples. More information on these studies and distribution maps of radiation doses can be found in the 30 August report: Corrections to Readings of Airborne Monitoring Surveys (Soil Concentration Map) based on Prepared Distribution Map of Radiation Doses.

On 30 September, the Nuclear Emergency Response Headquarters lifted the restriction of the Evacuation Prepared Areas in Case of an Emergency. Current evacuation areas are shown in the map provided by METI.

Japanese authorities have allowed temporary access to evacuated areas for residents and business owners. Access is provided to allow for retrieval of belongings and is conducted such that proper radiation protection and monitoring measures are taken.

For more details on actions taken by Japanese authorities to assist residents in the area, please refer to the 17 October version of the document: Roadmap for Immediate Actions for Assistance of Residents Affected by the Nuclear Incident.

Food monitoring collection and data is provided by the Ministry of Health, Labour and Welfare. As of 26 October, current food restrictions are available here.

What is the current status of the Fukushima Daiichi Nuclear Power Plant?

An important element of TEPCO's Roadmap Towards Restoration is to use circulating water to remove heat from Units 1-3 at the Fukushima plant. TEPCO has established a system to circulate cooling water through the reactors, treat accumulated water in the affected buildings and reuse water to inject into the reactors. Systems have been established to remove radioactive materials desalinate accumulated water.

On 22 October, TEPCO made available an English-language overview of the Effort for Treating Radioactive Accumulated Water. (A companion video presentation is available here).

TEPCO has reported that the temperatures in the reactor pressure vessels (RPV) of Units 1-3 have stabilized below 100 degrees. Bringing the temperatures below 100 degrees Celsius is an important step in stabilizing the reactors.

In addition to recirculating water to remove heat from Units 1-3, additional measures have been taken by TEPCO to manage the volume of water used to cool the reactors. Large tanks to store contaminated water from the cooling process have recently been set up, and an additional 2 800 tons of water storage capacity was installed on 17 September.

Approximately 128 140 tons of accumulated, contaminated water has been processed chemically as of 13 October. This process reduces caesium concentration in the water, improving its suitability for storage and further treatment.

TEPCO has also taken action to reduce the amount of contaminated water entering the ocean. On 28 September, a steel pipe sheet pile was completed at the south side of the intake canal for Units 1-4.

To reduce the dispersion of radionuclides to the environment, a steel superstructure has been constructed to cover Unit 1. The final roof panel was installed on 14 October.

Measures to remove loose debris on-site continue, and approximately 700 container-loads of debris have been gathered and stored as of 17 October.

Table 1: Status of Cooling Water Flow, Temperatures and Pressure at Units 1, 2 and 3

TEPCO's Fukushima Daiichi Nuclear Power Plant station reactors 1, 2 and 3 require circulating water to remove heat from their fuel.

Plant operators are working to bring the reactors into a "cold shutdown condition" defined by TEPCO and the Nuclear Emergency Response Headquarters as:

  1. Lowering the coolant water temperature to below 100 degrees centigrade while reducing the pressure inside the reactor vessels to the same as the outside air pressure, or 1 atmosphere (atm); and
  2. Bringing release of radioactive materials from primary containment vessel under control and reducing public radiation exposure by additional release (not to exceed 1 mSv/year at the site boundary as a target).

All data below are provided to the IAEA by Japanese authorities:

Indications Measurement Reactor
Unit 1 Unit 2 Unit 3
Water Flow Into Reactor1 Litres/hour 4 000 10 000 10 800
Reactor Vessel Pressure atm 1.10 1.22 -0.80
Outer Containment Vessel Pressure2 atm 1.21 1.22 1.02
Reactor Vessel Temperature (Feed Water Nozzle)3 °C 67.2 72.8 67.8
Reactor Vessel Temperature (At Bottom of Reactor)4 °C 69.3 77.7 71.6
Suppression Pool Pressure5 atm .95 Below Scale6 1.88
Date/Time of Data Acquisition   27 October
12:00 UTC
27 October
12:00 UTC
27 October
12:00 UTC
Notes:

1 Plant operators are pumping water into Unit 1 through one injection point and through two injections points in Units 2 and 3.
2 The containment vessel completely surrounds the reactor vessel and support systems. It is designed to prevent the release of radioactive materials following an accident. Japanese plant operators are working to reduce the pressure in the containment vessel to 1 atmosphere, the same as the outside air pressure.
3 The temperature of the coolant water as it is pumped into the reactor vessels.
4 The temperature of the coolant water, measured at the bottom of the reactor vessel.
5 The suppression pool is designed to limit pressure in the containment vessel during an accident by condensing steam from the containment vessel. Japanese workers are aiming to get this pressure down to 1 atmosphere.
6 "Below scale" means the reading is below the lowest indication the instrument is capable of detecting. This is typically an indication that an instrument has somehow failed.

Further information regarding progress on-site is available in the 17 October update: Roadmap Towards Restoration from the Accident at Fukushima Daiichi Nuclear Power Station.

What protective measures have been taken for the workers at Fukushima Daiichi?

TEPCO has worked to improve working conditions at Fukushima Daiichi by increasing the number of rest stations at the work site. In addition, the living environment has been improved through the provision of temporary dormitories, meals, bathing and laundry facilities. TEPCO has constructed and continues to develop an onsite medical facility staffed by doctors and nurses trained in treatment for radiation injuries. This staff and its services are available 24/7 in the event of a medical emergency.

TEPCO performs regular monitoring of its workers for both internal and external radiation exposure. Workers use industry standard personal dosimeters that provide a reading of how much external radiation each individual has been exposed to throughout the course of their work. Radiation monitoring capabilities continue to be enhanced. One example of these enhanced capabilities is through the installation of an additional 12 whole body counting units since 3 October. Whole body counting units are specialized radiation monitoring units that are used to detect if any radioactive material has been received internally.

What is the IAEA's strategy for strengthening global nuclear safety?

In response to the Fukushima accident, IAEA Member States unanimously approved the IAEA Action Plan on Nuclear Safety in September 2011 that sets out a programme of work to strengthen the global nuclear safety framework. These actions require a concerted effort from the IAEA Member States and the IAEA Secretariat for the coming years. A dedicated Action Plan Team is now implementing measures set out in the Action Plan.

Learn more about the Action Plan here.

How has the IAEA responded to the Fukushima accident?

In the event of a large-scale radiation emergency, the IAEA's role is to provide prompt notification of the event to its Member States and international organizations, coordinate international assistance upon request of the accident state and disseminate accurate and timely public information on the accident.

The IAEA conducts these activities primarily through its Incident and Emergency Centre (IEC), a 24-hour round-the-clock response centre based at IAEA headquarters in Vienna. The IEC was activated on 11 March in the hours following the Japanese earthquake and tsunami and established contact with the IAEA's emergency counterpart in Japan, the Nuclear and Industrial Safety Agency (NISA).

Upon activation, the IEC 1) began to distribute information on the accident status to the IAEA's 151 member states and several international organizations, 2) offered emergency assistance to Japan, and 3) provided continuous updates on the accident status via the IAEA website and other communications channels.

Since March 11, the IAEA instituted several measures to assist Japan through arrangements established by the organization and international nuclear and legal frameworks. Following the accident, the IAEA dispatched several teams of specialized technical missions to Japan to 1) monitor radiation levels throughout the country, including locations around the Fukushima Daiichi nuclear plant, 2) discuss technical issues with the Japanese authorities related to the boiling water nuclear reactor design used at the Fukushima plant, 3) participate in marine radiation monitoring missions off the coast of the Fukushima plant, and 4) provide assistance, in coordination with the Food and Agricultural Organization (FAO), on technical issues related to food and agricultural safety.

IAEA Director General Yukiya Amano travelled twice to Japan to express solidarity and full support to the Japanese people, confer with the Japanese government and to survey the damage and current recovery efforts at Fukushima Daiichi.

Two high-level international missions have been sent to Japan in recent months. From late May through early June, the IAEA dispatched a team of nuclear power and safety experts to Japan to gather a comprehensive set of conclusions and lessons learned that have been distributed through the global nuclear community. Its full mission report can be accessed here.

A recent mission conducted in October focused on the remediation of areas off-site the Fukushima Nuclear Power Plant affected by the consequences of the 11 March accident. A preliminary report of its findings can be accessed here.

Since the accident occurred on 11 March, the Director General has provided updates on the Fukushima Daiichi accident to the general public and IAEA member states.

See Story Resources for more information.

-- by IAEA Division of Public Information. Staff from the IAEA's Incident and Emergency Centre provide on-going support in producing these Status Reports.


(Note to Media: We encourage you to republish these stories and kindly request attribution to the IAEA).