Third quarter of 2002

Whistleblowing turns into tornado: TEPCO’s falsification of safety records plunges Japanese nuclear industry into deep crisis

WISE-Paris, 6 September 2002

[Posted 07/09/2002]
[Corrected 11/09/2002]
[Corrected 17/09/2002]

We personally hurt the public’s trust in us(1) were TEPCO’s President words after revelations that the main Japanese power company had filed falsified voluntary inspection reports at three nuclear power plants for years. The scandal could plunge the whole country nuclear industry into the worst crisis it ever went through, with serious secondary consequences worldwide, especially to the plutonium industry in Europe.

The falsification, unveiled by the Japanese Nuclear and Industrial Safety Agency (NISA) on 29 August 2002, concerned safety records in reports of internal inspections that TEPCO filed to the safety authorities. NISA is an agency of the Ministry of Economy, Trade and Industry (METI). The Ministry’s services started investigating the case in July 2000, when an engineer working for General Electric International Inc. (GEI), the daughter company of General Electric Co. (GE) in Japan, alerted the agency. It is GEI that was performing inspections of the reactors operated by TEPCO.

The ongoing investigations have yet to determine the real extent of the falsifications. The document released by NISA on 29 August 2002 reported 29 cases of suspect inspections and repair records, concerning thirteen boiling water reactors (BWRs) in the three nuclear power plants of Kashiwazaki-Kariwa, Fukushima Dai-Ichi (number 1) and Fukushima Dai-Ni (number 2) (2). Although the cases involve other damages, most of them are cracks in the vessel « shroud ». The shroud is a stainless steel cylinder made of carbon steel plates that are curved and then welded together, contained in the reactor vessel and surrounding the core. It is destined to regulate the flow route of the primary water which is led from outside of the core shroud to the core by jet pumps, and to maintain the fuel assemblies geometry between the top guide and the bottom core plate. If some of the concealed cracks have been repaired since, it seems that the problems TEPCO failed to report were never fixed in at least eight cases.

Cracks in the reactors vessels shrouds are due to unsufficient resistance of alloy to corrosion and appear particularly in the welding zones. They constitute potential sources of major accidents since they can lead to perturbations of the primary coolant flow as well as damages on the fuel assemblies.. Although NISA denied there was immediate safety risk due to the situation of the eight reactors left unrepaired, it recognized the potential severity of the problems. (3)

The first announcement by NISA included falsification of records from the late 1980s to the 1990s, running over a period of 14 or 15 years. But since the 29 of August, ongoing official and media investigations have already uncovered more cases, continuing up to 2001. After cracks in the shroud of the Fukushima Dai-Ni Unit 3 reactor were reported to METI during the summer of 2001, instruction was given to all utilities to check for similar cracking at other reactors. In its report to METI about the subsequent inspections, TEPCO covered-up the existence of cracks in the shrouds of three reactors in Fukushima (Dai-Ichi, Unit 4, and Dai-Ni, Units 2 and 4), and concealed the full extent of the cracking in the Dai-Ni Unit 3 shroud.

All four units will be shut-down for inspection of the damaged parts in September or October 2002, anticipating their next scheduled outage, TEPCO announced the 1st of September. Fukushima Dai-Ni Unit 2 was shut down as early as 3 September 2002, after a radiation leakage was detected, possibly due to a fuel leak (4). TEPCO has also shut down for repair, on 3 September 2002, the Unit 5 of the Kashiwazaki-Kariwa plant, where the company announced « newly-discovered » cracks in the shroud on 24 August 2002, only a few days before the falsification scandal broke up in the news.

The 29 falsified reports also include cracks in some reactors’ shrouds that have since been replaced. This was the case of three other reactors in Fukushima Dai-Ichi (Units 1, 3 and 5). According to Mainichi Newspaper edition (5) of 4 September 2002, the cracks had been identified by TEPCO before the company replaced the shrouds, but they were not mentioned in the applications submitted to the safety authorities for the operations, which only referred to “preventive maintenance”. Unlike the voluntary inspections reports, which the power companies are not required by law to submit to the authorities, such applications are compulsory documents included in safety control procedures.

Ongoing investigations should also clarify responsibilities in the falsifications and their covering. It appears almost certain that the falsification of inspection reports by GEI was concerted and instructed by senior managers in TEPCO. According to newspapers reports, METI’s investigation would now indicate that over 100 employees were involved in these cover-ups (6).

Moreover, there is suspicion of a cover-up by the METI, as it took NISA more than two years to make the information public. According to MET'I’s explanations, it is not before the informer resigned from GE, in November 2001, that NISA approached GE and GEI officials and obtained their cooperation. Besides, METI claimed that before this move, the investigation did not gather enough evidence to force TEPCO officials into admitting the falsifications. TEPCO did not set up an internal investigating committee on the matter before May 2002.

Soon after the public announcement by NISA, TEPCO officials declared that they “would like to uncover the entire truth by mid September(7). Nevertheless, before the investigations go further, TEPCO confirmed in a press release on 2 September 2002, the announced plans for resignations of several executives, including its Chairman, Hiroshi Araki, at the end of the month and its President, Nobuya Minami, by mid-October.

The affair will cause serious harm to the nuclear industry, in Japan and worldwide. While most countries have completed or are engaged in the opening of their electricity market, the attitude of TEPCO, one of the largest private power company in the world, and General Electric, reinforces already strong concern over the weakening of nuclear safety under the pressure of economic competition.

The scandal will also have severe consequences for the plutonium industry, as it casts shadow on the development of the Japanese Pluthermal plan to re-use plutonium arising from reprocessing of spent fuel in thermal reactors. The news of TEPCO falsifications broke up just a few days before the company could obtain the last authorization needed for a major step of the program, with the first introduction of MOX fuel (mixed oxide of uranium and plutonium) in a Japanese thermal reactor. TEPCO President admitted that the company was not anymore in the position to "ask for understanding to continue the MOX fuel project". (8) Major victims could be European reprocessing companies, the British BNFL and French COGEMA, both producers of MOX fuel for Japan. The first constructed a whole MOX fabrication plant, in Sellafield, arguing of its economic justification because of forthcoming Japanese contracts; the second constructed a second line, producing MOX for BWRs, in its Melox plant with the only prospect of providing Japan utilities.


  1. Declaration of M. Nobuya Minami, President of Tokyo Electric Power Co. (TEPCO), as reported by the Asahi Shimbun, "TEPCO faked repair reports at 3 nuke plants", 30 August, 2002
  2. See the Plutonium Investigation map of nuclear installations in Japan,
  3. Yomiuri Shimbun, "False records found at N-plants", 30 August, 2002
  4. The Japan Times, "Radiation leak shuts down Tepco reactor", 4 September, 2002
  5. Mainichi Daily News, 4 September, 2002, "TEPCO inspectors admit to covering up nuclear reactor problems"
    Mainichi Daily News, 4 September, 2002, Editorial, "TEPCO must expunge its cover-up ethos"
  6. The Asahi Shimbun, "TEPCO execs linked to cover-up as 100 investigated from within", 2 September, 2002
  7. Bloomberg, "Tokyo Electric Investigates Nuclear Plant Reports", 29 August, 2002
  8. In the Asahi Shimbun, 30 August, 2002, op. cit.

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