Drills | Security

Emergency preparedness in Japan

24 January 2011



The organizational structure, procedures and infrastructure for nuclear emergency response were established after the JCO accident and are regularly improved through exercises, drills and training. By Toshihiro Funahashi


A September 1999 criticality incident at Japan Nuclear Fuel Conversion Co (JCO) in Tokai-Mura during preparation of a batch of fuel caused a release of radiation that eventually proved fatal for two workers; 100 others eventually received a dose of 1 mSv. The IAEA blamed the accident on ‘human error and serious breaches of safety principles’. But the errors of the JCO workers were compounded by the organisation’s improper placement of monitoring sensors and the organisation’s factual misunderstanding of the incident. JCO did not initially report the incident. This meant that a coordinated nuclear disaster response to the incident, and the start of radiation monitoring, were delayed. The report from a subsequent investigation into the JCO incident recommended that a new law be instituted that obliges nuclear licensees to notify the authorities of accidents. It also proposed that a new system be implemented, bringing together disaster response organisations including the fire service, police, coast guard, ambulance and self-defence forces.

Response organisation, procedures and infrastructure

Now, the national government works with local responders to organise the emergency response to a nuclear incident in three steps.

Step 1. An accident occurs at a nuclear power plant. By law, the licensee must notify the national Nuclear and Industrial Safety Agency.

Step 2. A minister in its controlling organisation, the Ministry of Economy, Trade and Industry, notifies the prime minister’s office. The central nuclear emergency response headquarters (NERHQ) of the national government issues a nuclear emergency declaration, which also includes instructions about preventative measures. It receives technical advice from the Nuclear Safety Commission. The NERHQ sends a specialist and the NSC sends a commissioner to the site.

Step 3. After the emergency declaration is received, the local office of the national government’s NERHQ arranges prevention measures based on factors including facility information, climate and monitoring.

Nuclear emergency response operations are coordinated in one of 20 so-called off-site centres spread across Japan, which are close to, but not inside, nuclear facilities. The off-site centre’s role is to be the main centre of information, incident analysis, and emergency plan organisation and direction. Two or three senior specialists for nuclear emergency preparedness work in each OFC. In normal conditions, the specialists work as nuclear power safety inspectors, checking plant operation from the viewpoint of regulation. During an emergency, the specialists organize prevention measures as a secretariat and report it to a joint council for nuclear emergency response. The joint council includes not only the local office of the national government’s NERHQ and the senior specialists, but also representatives of the Nuclear Safety Commission and prefectural and municipal NERHQs.

The joint council devises instructions to residents for evacuation and/or sheltering. It also instructs the emergency services and coast guard, self-defence force, Japan Nuclear Energy Safety Organisation (JNES), the National Institute of Radiological Sciences, the Japan Atomic Energy Agency, and other bodies.

JNES has constructed a dedicated high-speed network system connecting the 20 off-site centres and other agencies called Emergency Preparedness Response Network (EPRNet). It includes video conferencing systems, e-mail, telephone, fax, and connections to a meteorological information service, a plant information collection, diagnosis, prognosis and analytical prediction tool (called ERSS), and an emergency environmental dose prediction tool (called SPEEDI).


Architecture of EPRNet
Architecture of EPRNet


Practice for improvement

The government implements a full-scale nuclear emergency response exercise once a year. All of the related government organizations, including the prime minister himself, participate. During the exercise, each agency’s performance and cooperation with other agencies is verified. The last exercise took place at Hamaoka, Shizuoka prefecture, in October 2010; the next exercise will be announced in April 2011. Each local government that hosts nuclear facilities also implements an emergency response exercise once a year. JNES ensures the consistency between the national and local government exercises.

In addition to the full-scale exercises, JNES also conducts table-top role-playing exercises at each off-site centre. Participants—the same representatives involved in the full-scale exercises—are not given the full accident scenario, but must act on plant information to take appropriate prevention measures. These exercises are intended to improve communications and decision-making.

JNES collects lessons learned from these exercises and identifies infrastructural, behavioural and procedural issues in implementation of protective actions. It feeds back these findings to the exercise and the infrastructure, thereby enhancing emergency preparedness.


Author Info:

Toshihiro Funahashi, Assistant Director-General, Japan Nuclear Energy Safety Organisation, Nuclear Emergency Preparedness and Response Division, Incorporated Administrative Agency, TOKYUREIT Toranomon Building, 17-1, Toranomon 3-chome, Minato-ku, Tokyo 105-0001, Japan

This article is based on a presentation given at a technical conference last year, and is adapted from the below with IAEA permission.

International Atomic Energy Agency, International Conference on Challenges Faced by Technical and Scientific Support Organizations (TSOs) in Enhancing Nuclear Safety and Security, 25-29 October 2010, Tokyo, Japan, Proceedings Series, IAEA, Vienna, (2011).

Architecture of EPRNet Architecture of EPRNet


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