Japan Atomic Energy Agency

Sector of Nuclear Safety Research and Emergency Preparedness
Nuclear Emergency Assistance and Training Center

Top > Activities> First responses >Emergency Responses to the Accident at TEPCO's Fukushima Daiichi NPS

Dispatch to Fukushima Prefecture

Environmental radiation monitoring and population monitoring

By a request from the Ministry of Education, Culture, Sports, Science and Technology (MEXT), the JAEA dispatched seven members of experts on environmental radiation monitoring to Fukushima Nuclear Off-site Center which was located in Ookuma Town. They left the NEAT at 1:54 on March 12, 2011 and arrived at the Center at 6:30. The first team was transported in helicopter of the Self-Defense Force. The second and following teams were transported on JAEA's bus and other vehicles. The first and second teams based in the Fukushima Nuclear Center, which was located next to the Fukushima Nuclear Off-site Center; they measured the environmental air-dose rates at the places not far from the Centers with a cooperation with the MEXT, Fukushima Prefecture and other relevant organizations.

At the night of March 14, a decision was made to relocate the emergency operation center, i.e. the Off-site Center, in Okuma Town, into the prefectural office building in Fukushima City. The first and second teams of the JAEA returned to the NEAT-Ibaraki. The third and following teams were dispatched to the alternative Off-site Center in Fukushima City. The fifth and following teams left every two days and stayed in Fukushima for five days. The odd-numbered teams executed monitoring in cooperation with the MEXT as members of radiation monitoring support group, and the even-numbered teams prepared for emergency medical activities as members of population monitoring support group and they located at the Fukushima Medical University. From June, both of even and odd teams worked as members of the radiation monitoring support group.

The radiation monitoring support group executed measurement of environmental radiation using a monitoring vehicle every day in a region of outside of a 20 km radius; it also measured concentrations of radioactive materials in the air and in the soil. Occasionally by a request of Fukushima Prefecture, the group also measured environmental radiation in school yards and in temporary visit areas prior the visit. The MEXT summarized the measured and analyzed results of the JAEA and others; the summarized results were open to public through the MEXT website. (Later the results were publicized through the website of Nuclear Regulation Authority.)

The population monitoring support group of the JAEA deployed two special vehicles, i.e. a vehicle mounting four shower facilities and a vehicle mounting two body-surface counters, to Fukushima Medical University, in order to prepare for a massive contamination of the public.

a photo for departure of the dispatched experts to Fukushima1
Departure of the dispatched experts to Fukushima
a photo in discussion of dispatched experts on environmental radiation monitoring in the Fukushima monitoring center
Discussion on environmental radiation monitoring in the Fukushima monitoring center

a photo in radiation monitoring in Fukushima Prefecture
Environmental monitoring in Fukushima
a photo of dispatched vehicle carrying showers that was located at Fukushima Medical University
Dispatched vehicle carrying showers located at Fukushima Medical University

Radiation helplines operated in Fukushima Prefecture

By a request from the Ministry of Economy, Trade and Industry (METI), the JAEA dispatched two experts in turn to the community hall building of Fukushima Prefecture from the start of radiation helplines mainly for residents in Fukushima Prefecture. By observing news reports in addition to their background knowledge and experiences, they responded to questions from the residents in cooperation with prefectural officers by answering mainly technical issues.

The radiation helplines were open for 24 hours in the early months. The JAEA dispatched further 2 experts, i.e. totally 4 experts all the time since March 26 until April 29; they played a crucial role in the telephone responses. The open time was changed from 8:00 to 21:00 since April 30. The dispatch of JAEA experts continued until August 8; a new one-stop service started in Fukushima City on the next day.

two JAEA experts who were dispatched at the radiation helplines in Fukushima Prefecture
The experts who were dispatched at radiation helplines in Fukushima Prefecture

Evaluation of internal exposure

The NEAT responded to requests for internal dose measurement with supplying three vehicles mounting a whole-body counter each, hereafter we call whole-body counter vehicles (WBCs); two of them were ours and one was owned by the Nuclear Fuel Cycle Engineering Laboratories of the JAEA.

By a request from the MEXT on March 13, the NEAT dispatched its WBC located at NEAT-Ibaraki in Hitachinaka City to Fukushima Medical University in Fukushima City on March 15 to prepare for a future possible activity of population monitoring support group; the NEAT transfered another WBC located in Fukui to Ibaraki for a future need.

The Tokyo Electric Power Company (TEPCO) requested the JAEA to help in measuring internal radiation doses of workers in Fukushima Daiichi Nuclear Power Station on March 20. To meet the request, the JAEA transferred the WBC from the Fukushima Medical University to Onahama Coal Center of TEPCO; then dispatched a few experts and started the internal radiation dose examination of emergency workers on March 21. After evaluation by JAEA experts, the results were reported to the TEPCO. The measurements and dose evaluation have continued until April 25, and the total number of workers examined was about 330. Later, the measurement was succeeded to TEPCO's persons in charge following a training by JAEA's experts. The dose evaluation by the JAEA experts had made until that of the measurements performed on May 12. On May 9, the JAEA lent TEPCO another WBC, and it was utilized for measurement at various branch offices of TEPCO. The third WBC was dispatched to Onahama Coal Center on May 30. The dispatched WBCs returned to the JAEA when safety inspection or check up was required.

a photo of JAEA's two vehicles carrying a whole-body counter each dispatched and located at Onahama Coal Center in Iwaki City
Two vehicles carrying a whole-body counter each dispatched and located at Onahama Coal Center in Iwaki City

Support to the General Affairs Squad of the Local Nuclear Emergency Response Headquarters and support to the residents in their temporary re-entry into the restricted area

On May 6, the JAEA started to dispatch an expert to the General Affairs Squad of the Fukushima Off-site Center, and he gave advice to Director-General of Local Nuclear Emergency Response Headquarters and other members of the Headquarters as appropriate. for example, he gave technical advices on temporary re-entry for the public benefit service activities and/or of residents. His first mission was to instruct the usage of radiation detectors for public benefit service activities and to examine the clothing for residents to enter the restricted area. Since late May 2011, the JAEA increased the number of dispatched experts to three or four; one made technical advices and other two to three supported in preparation for and management of transit hubs for residents' home-coming.

In responding to requests from the Local Nuclear Emergency Response Headquarters, the JAEA dispatched 10 to 30 members of its staff and retired employees to serve as safety managers for the temporary re-entry of local residents. Some members of the Institute of Professional Engineers, Japan joined the support activities in a later stage.

a photo in the the alternative off-site center in Fukushima City
A scene in the alternative off-site center in Fukushima City
a photo of an assistance at a transit hub for temporary re-entry residents
Assistance at a transit hub for temporary re-entry residents

Training in radiation measurement

Fukushima Prefecture conducted training in radioactive measurement at Fukushima Technology Centre in Koriyama City for staff of private corporations to enhance their response capabilities to guarantee non-contamination proof from radioactivity. On April 21, Fukushima Prefecture requested the JAEA to dispatch instructors for the training. The JAEA sent off a team of a lecturer and a few instructors in cooperation of retired employees at each training, which was performed on April 28, May 12, 19, 25 and 26 and June 2. The training consisted of a lecture on survey meter treatment and practices of measurement with the survey meters.

a photo of radiation measurement seminar in Koriyama City
Radiation measurement seminar in Koriyama City

Radiation monitoring of school buildings and schoolyards

By a request from the MEXT, the NEAT executed dose rate measurement of the schoolyards and schoolrooms in Fukushima Prefecture with a collaboration of retired employees of the JAEA. The measurements were executed once a week for total 56 elementary schools, junior high schools and so on since April 14. When a high dose rate was detected at such a school, dose rate measurement mas additionally made for schoolyard equipment, flowerbeds and school routes. Detailed surveys were also conducted such as concentration distribution of radioactive materials along the depth of the soil and radioactive material concentration of dust in the air.

From late June, objects were expanded, and we measured radiation dose rates at technical colleges on June 23 and along the hiking courses of National Youth Outdoor Learning Centers on June 30.

a photo of JAEA staff in radiation monitoring on school ground
Radiation monitoring on school ground

Dispatch to Ibaraki Prefecture

Since mid- until late March, the JAEA performed the following supports upon request from Ibaraki Prefecture:

Technical supports and advices

Environmental dose estimation using a World-wide System for Prediction of Environmental Emergency Dose Information, Version II (WSPEEDI-II)

The Nuclear Science and Engineering Directorate (NSED) of the JAEA had developed WSPEEDI, a world-wide version of SPEEDI (System for Prediction of Environmental Emergency Dose Information), and released its 2nd version WSPEEDI-II on February 5, 2009. The main functions of WSPEEDI-II were (1) to estimate diffusions of radioactive materials released to the atmosphere assuming a release of radioactive materials and (2) to estimate the source origin and release rates by coupling the environmental monitoring data (source estimation function).

In an early morning of March 15, the JAEA received a request from the Ministry of Education, Culture, Sports, Science and Technology (MEXT) to predict the atmospheric diffusion of radioactive materials. However, the computer system of NSED for research was not available because of a loss of power. The NEAT, having implemented the WSPEEDI-II system and compiled its operational manual since the preceding fiscal year, decided to carry out the calculation at the NEAT in cooperation with NSED. The NEAT reported the first calculation results to the MEXT at 12:34. At 15:10, the MEXT requested the JAEA to perform source estimation calculations. The JAEA reported its calculation results to the MEXT at 15:10.

The results of diffusion prediction calculation with the WSPEEDI-II were sent also to the Nuclear Safety Committee since the next day, i.e. March 16. The calculations, which were made by assuming a release of radioactive materials for a few days from the reporting day at a constant rate, were routinely performed every day until May 12 and sent in the morning (during March 17 and April 8) and in the afternoon (during March 19 and March 25). Also, even after April 9, the calculation was continued until May 12.

Since the computer system of NSED for research was resumed in several days, non-routine calculations assuming specifically the release timings and rates were performed by the NSED, and the results were published by the MEXT.

On March 20, Iaraki Prefecture requested the JAEA to calculate the ground-level concentration of iodine for reference to develop an effective monitoring plan; the JAEA calculated and sent the results on the next day.

a photo of the prediction calculation with WSPEEDI-II for global diffusion of radioactive materials
Prediction calculation with WSPEEDI-II for global diffusion of radioactive materials

Opening of radiation helplines

On March 13, the MEXT requested the JAEA to supply toll-free services to reply to questions from residents on the health effect due to the accident at TEPCO's Fukushima Daiichi Nuclear Power Station, which will be called "radiation helplines" hereafter. The JAEA opened the radiation helplines on March 17, and received the first inquiry at 13:18, just eight minutes after than 13:10 when the MEXT issued a press release on the radiation helplines. The radiation helplines had been opened for one year and a half and closed on September 18, 2012.

In the beginning, the JAEA opened eight telephone lines from 10:00 to 21:00. Since March 25, universities and other relevant institutions also opened their radiation helplines, however, these helplines had not been maintained long, and since June 11, only the JAEA supplied the helplines under the MEXT; open hours had changed into from 9:00 to 18:00 since then.

The helplines were operated at the NEAT in a collaboration with major Branches of the JAEA. At the JAEA, 10 to 20 members responded per day, and the total number of responders extended to 5,618. The JAEA responded to roughly 300 calls per day for the beginning and the number gradually decreased; for example, about 100 calls per day in October. The total number of inquiries the JAEA responded was 34,581.

Information about the inquires and responses were tabled and categorized every day, and it was shared with the MEXT.

The radiation helplines continued until September 2012, and details are given in a separate web page.

a photo of JAEA staff responding to questions from residents through the radiation helplines
Responding to questions from residents through the radiation helplines

Analysis of soil samples (on-site of Fukushima Daiichi NPS) and marine samples

On March 21, a request from the Ministry of Economy, Trade and Industry (METI) was conveyed through the MEXT to measure plutonium contents of the soil on site of TEPCO's Fukushima Daiichi NPS and to analyze nuclides of samples by gamma rays in a prompt way. The JAEA responded to the request by accomplishing the measurement and analysis at some of its institutes.

On March 22, on a request from the MEXT to measure the radioactive concentrations of sea-water samples and dust samples in the marine area, which were obtained by Japan Agency for Marine-Earth Science and Technology (JAMSTEC), the NEAT responded to the request by asking the tasks to some of the institutes of JAEA.

Advises to National, Fukushima- and Ibaraki-Prefectural governments and information supply to the public

The JAEA cooperated with the national government, especially with the Nuclear Safety Committee (NSC) and the MEXT. For example, the JAEA dispatched its experts to the NSC and contributed technological studies in the fields of diffusion evaluation analysis and radiation management. Some establishments of the JAEA aggregated knowledge and data, and supply them to the dispatched experts.

For compiling environmental radiation and radioactivity data at the Emergency Operation Center (EOC) of the MEXT, the JAEA dispatched its experts and they carried out cooperation activities on 24-hour schedules. The JAEA conducted also cooperation activities for international response activities of the MEXT.

The JAEA answered to inquiries from the public directly for the initial stage, and through radiation hotlines following the system was established. Other activities of the JAEA for the national and local governments were replies to the technical questions, dispatching experts, analyses and measurements of samples, training in radiation measuring and holding workshops, almost all of which were carried out upon requests from the governments.

Utilization of equipment and facilities

Utilization of special vehicles

The NEAT possessed two environmental monitoring vehicles, two whole-body counting (WBC) vehicles, two body-surface contamination monitoring vehicles, a decontamination vehicle, two command vehicles and an equipment carrier either at the head office in Hitachinaka City or at Fukui Branch in Tsuruga City. The NEAT dispatched the vehicles located in Hitachinaka City to Fukushima Prefecture and moved the vehicles located in Tsuruga City to Hitachinaka City. Timelines for utilization of the special vehicles are shown in the table below.

Timelines for utilization of the special vehicles

The environmental monitoring vehicles were utilized by the radiation monitoring support group in the activities of radiation monitoring mainly outside of a 20 km radius region from the TEPCO's Fukushima Daiichi NPS.

The WBC vehicles were lent to the TEPCO whose fixed-type WBCs in the NPS were unable to use, and they were utilized to radiation exposure management of the workers.

The body-surface contamination monitoring vehicle and the decontamination vehicle were deployed at the Fukushima Medical University to be utilized by Medical Squad if needed. Since June, they returned to NEAT in Hitachinaka City on standby, in considering that the probability of utilizing them in an emergency in Fukushima Prefecture was low and that they could be reached to Fukushima Prefecture within a few hours if necessary. The command vehicle stayed in Fukushima City.

Dispatched vehicles carrying a whole-body counter located in Iwaki City
Two vehicles carrying a whole-body counter each dispatched and located in Iwaki City
Dispatched vehicle carrying showers located at Fukushima Medical University
Dispatched vehicle carrying showers located at Fukushima Medical University

The equipment carrier was lent to the Emergency Headquarters of the JAEA, which became headquarters of Fukushima Partnership Operations later, and it was utilized as robot carrying car for supporting remote operation of the JAEA robot.

Lending equipment

Radiation survey meters and personal dosimeters of the JAEA were mainly used by the JAEA staff themselves; some of them were offered to national and local governments and TEPCO, which contribute them to strengthen their capabilities to measure radioactivities. The main renters were listed below:

Kind of detectors Number Borrower
Ionization chamber, Teletector, etc. about 40 TEPCO
GM survey meter about 10 Local nuclear emergency response headquarters
NaI survey meter, etc several Local governments
NaI survey meter, etc several METI, etc

Utilization of facilities (infrastructures of Emergency Assistance Building and various systems)

The information sharing room of NEAT, located on the 2nd floor of the Emergency Assistance Building of NEAT-Ibaraki, worked as the hub of supporting activities of the JAEA to the emergencies in Fukushima Prefecture. The followings were main facilities of the Emergency Assistance Building utilized since the 2011 off the Pacific coast of Tohoku Earthquake.

  1. Quake-absorbing structure

    A quake-absorbing structure was installed under the Emergency Assistance Building on the basement, and there were no damages found in the Building.

  2. Emergency power supplies

    Although commercial power supply was interrupted for several days, main functions were applicable by emergency power supplies.

  3. Water tanks for general service water

    There were two water tanks in underground with a capacity of 25 cubic meters each, in which general water was stored and utilized in the flushing toilets.

  4. Multiple communication network systems

    The NEAT had three independent communication network systems as shown in the figure below. The first one was the unified network of Nuclear and Industrial Safety Agency (NISA) for nuclear emergency response, which was utilized in TV conference with the central government and off-site centers and for information sharing of the System for Prediction of Environment Emergency Dose Information (SPEEDI) and the Emergency Response Support System (ERSS). The other two were public network and JAEA's intra-network. Since occurrence of the earthquakes, there were no occasions all the networks went dead. The NEAT had four priority telephone lines in disaster, and they worked effectively. Other than the three communication network systems mentioned above, the NEAT had installed Cabinet Office's Anti-Disaster Radio Communication System and satellite telephone system.

    NEAT Network

  5. Information sharing system for emergency management

    For continuity of responses during 24 hours a day in shift works, recording and sharing of information were important. Emergency Information Clearinghouse (ECHO) was very helpful in recording our responses.

  6. Emergency earthquake notification

    Emergency notification system was installed at the NEAT. When an earthquake equal or larger than 4 in the Japan Meteorological Agency (JMA) seismic intensity scale was foreseen in Hitachinaka City, an announcement was made inside of the NEAT buildings. That helped the staff to prepare in mind for a large earthquake.

  7. TV receivers

    In the NEAT situation room, eight television programs were available in parallel through terrestrial and satellite broadcasting systems. This television receivers were very helpful to obtain information especially immediately after the earthquake.


The JAEA was well prepared for dispatching vehicles and experts to support local government in radiological emergency. In addition to the special vehicles, other vehicles such as commuter buses and official cars of the JAEA were applicable to transfer experts to Fukushima Prefecture from Ibaraki Prefecture where the main institutes of JAEA were located. The drivers agreed to drive a vehicle in an emergency situation by a contract, and they were trained in radiation effects and passed an examination at the NEAT before the Fukushima emergencies occurred.

One of the issues in responding to the emergency were stopping commodity distribution because of the large earthquakes, especially drinking water, food and oil, i.e, light oil and gasoline (petrol).

The NEAT had a very little stockpile of drinking water and food. Shortly after the earthquakes almost all shops were closed. In this circumstance, the NEAT managed the situation by takidashi (soup kitchen).

Main functions of the Emergency Assistance Building relied heavily on electricity from emergency electricity supplies. The NEAT tried hard and finally succeeded to obtain light oil for the fuel of emergency electricity supplies and gasoline for special vehicles and commuter cars.

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