JAEA Nuclear Non-proliferation Policy Letter   No.0004  2013.03.29

<< Lessons from the Fukushima Nuclear Accident on Nuclear Security >>

Yu Takeda1

1 Postdoctoral Fellow, Policy Research Office, Department of Science and Technology for Nuclear Material Management, Japan Atomic Energy Agency (JAEA).


Months after the accident at Fukushima Daiichi Nuclear Power Station (NPS) on March 11, 2011 (hereafter referred to as the Fukushima nuclear accident), numerous organizations investigated the causes of the accident and emergency response. In Japan, four committees shown in the Table are especially notable: the Government's committee, the plant operator Tokyo Electric Power Company (TEPCO)'s committee, the independent investigation commission established by Rebuild Japan Initiative Foundation, and National Diet commission. Although the main focus of the discussion of all the committees are nuclear safety rather than nuclear security, their findings suggest weakness of an NPS from terrorist attacks and possible countermeasures to those problems.

In addition, though independent of the above investigations, the Advisory Committee on Nuclear Security of Japan Atomic Energy Commission (JAEC) released its recommendations to strengthen nuclear security and lessons learned from the accident. Based on four reports and the JAEC's suggestions, this paper outlines discussions relating to nuclear security in Japan after the Fukushima nuclear accident.

[Table: Investigation reports and JAEC’s Recommendation]
Founder Established Release of final report English version
Government's committee Japanese government May 24, 2011 July 23, 2012 Available
TEPCO's committee Tokyo Electric Power Company June 2011 June 20, 2012 Available
Independent committee Rebuild Japan Initiative Foundation September 20, 2011 March 11, 2012 Not Available
Diet commission National Diet December 8, 2011 July 5, 2012 Available
JAEC Advisory Committee Japan Atomic Energy Commission December 16, 2006 March 9, 2012 Available

2.Implications of Fukushima Reports on Nuclear Security

According to the investigation reports, the Fukushima nuclear accident seems to have three implications for nuclear security: structural defect of the nuclear regulatory system, lack of the understanding of the importance of the auxiliary facilities in an NPS, and poor crisis management.

Firstly, the accident was at least partly due to insufficient nuclear safety regulations before the accident. While concerning parties were aware of reinforced safety and security measures in other countries, they were slow to tackle with fundamental improvements such as damage mitigation in case of station blackout that was regulated by the U.S. Nuclear Regulatory Commission in section B.5.b. regulation. According to the reports, the delay was caused by structural problems within the Japanese nuclear regulatory regime; regulatory bodies were busy to cope with minor accidents; they were under control of ministries in charge of promoting nuclear energy; and their staffers were routinely reshuffled as other bureaucrats were in Japan, which made them dependent on expertise of utility companies.

Secondly, damages to safety components rather than nuclear reactors themselves were triggers to catastrophes after the earthquake and tsunami. While the National Diet commission insisted that the earthquake could have damaged the nuclear reactor, the other three denied such possibilities and rather focused on damages caused by tsunami after the earthquake2 . In any case, they share the view that the accident was escalated as tsunami wiped out components such as emergency power generators and seawater pumps, which led to the loss of all power supply and cooling functions. It reaffirmed the concern that auxiliary facilities as well as nuclear reactors could be targets of terrorist attack3 .

Thirdly, there were numerous failures in emergency response. The Government committee and the independent committee emphasized operators' mismanagement of unit 1 of Fukushima Daiichi NPS for their delay to reduce the pressure of the reactor vessel and pour coolant. The National Diet commission rather described that the delay was caused by the failure of TEPCO to train its employees and prepare procedures for station blackout4 .

Nevertheless, all reports more or less criticized roles of the Prime Minister's Office as the International Atomic Energy Agency (IAEA) mission already pointed out5 . They described that Prime Minister Naoto Kan and his aides directly intervened in the handling of the Fukushima Daiichi NPS without sufficient information. Such intervention disrupted management of the reactor, planned chain of command in Japanese Government and TEPCO, and other emergency responses such as evacuation of residents.

In addition, four investigating committees show possible prescriptions to these problems. The two suggestions below are related to nuclear security.

One is the establishment of a new nuclear regulatory system. Committees except TEPCO's insisted that Japan should establish a new nuclear regulatory system that is independent of nuclear industries and other governmental agencies promoting nuclear energy. Such an organization, which was established as the Nuclear Regulatory Authority in September 2012, is expected to streamline regulations regarding nuclear safety and security by avoiding sectionalism seen in the previous nuclear regulatory regime.

The other is the improvement of organizations and standard procedures of emergency response. TEPCO's committee emphasized the need to improve emergency response organization while the independent commission discussed the creation of a unit in charge of on-the-ground disaster management that is equivalent to the U.S. Federal Emergency Management Agency.

2The National Diet of Japan, "Introduction", in The official report of The Fukushima Nuclear Accident Independent Investigation Commission, 2012, p.12. Members of National Diet commission were also split on damages of the earthquake to nuclear facilities. "Kensho genpatsu ziko houkokusho,"(Inspecting reports on Fukushima nuclear accident) July 29, 2012, Nihon Keizai Shinbun.
3 The Independent Investigation Commission on the Fukushima Nuclear Accident, Report, 2011, pp.340-343.
4TEPCO's committee denied these allegations. Tokyo Electric Power Company, Fukushima Nuclear Accident Analysis Report, 2012, pp.198-208.
5 Mission Report, "IAEA International Fact Finding Expert Mission of the Fukushima Dai-ichi NPP Accident Following the Great East Japan Earthquake and Tsunami," June 16, 2011,

3.Further Discussions: JAEC's recommendations

JAEC's Advisory Committee on Nuclear Security also studied lessons from the accident. Since the committee had already started to examine Japan's response to revisions of IAEA Nuclear Security Recommendations and the concept of nuclear security well before the accident, its study shed light on a wider range of security concerns that became apparent in the accident. In addition to damages of the earthquake and Tsunami described by the above reports, the advisory committee detailed two concerns on nuclear security.

One is the spread of information on the structure of NPSs and increasing interest in their potential vulnerability. The accident showed that nuclear hazards are so disastrous that an NPS could be a target of terrorist attacks. The committee concludes that the protection of nuclear facilities other than nuclear reactors should also be reinforced against such a threat.

The other is insider threat. At the earlier stage of the accident, there were unidentified personnel working within the Fukushima Daiichi NPS. Citing NTI Nuclear Materials Security Index, which described Japan's vulnerability to such trustworthiness of security personnel6 , the recommendation insists that Japanese nuclear industries need to restrict access to nuclear facilities and enhance identity verification of their employees.

Considering these lessons learned from the accident, the advisory committee pointed out the need to maintain security of nuclear facilities against terrorist threat even if facilities are under emergency conditions such as high radiation levels and station blackout.

6"Security Personnel Measures", NTI Nuclear Materials Security Index,

4.Looking ahead

The Fukushima nuclear accident prompted all the concerning parties in Japan to review nuclear safety and security systems. Although discussions in Japan is focused on unanswered questions such as causes of the accident and safety regulations, the Japanese Government started to strengthen restrictions on the access to nuclear facilities, the protection of facilities storing specified nuclear fuel materials, countermeasures against cyber terrorism, and security personnel stationed at nuclear facilities7 .

There remains a lot of untouched nuclear security concerns, however; nuclear safety and security measures are required to be in harmony; plant operators and security authorities need to cooperate to cope with heavily-armed terrorists; authorities and utilities managing nuclear power should be more sensitive to nuclear security, while security authorities would have a lot to learn about nuclear power; a nuclear security culture should be promoted among all concerning organizations while paying due regard for confidentiality. These issues are expected to be addressed in future by the Japanese Government, the United States-Japan Bilateral Commission on Civil Nuclear Cooperation established last April, and other numerous international conferences such as the Nuclear Security Summit.

7The Sasakawa Peace Foundation, The Fukushima Nuclear Accident and Crisis Management (September 2012), pp.77-78.