While the responsibilities for the development of advanced nuclear reactors had been taken away, JAERI was not abolished because it still had responsibilities for nuclear science research, including the construction of a commercial class nuclear powered ship (See inset on the Mutsu). JAERI also continued some research activities on nuclear power generation, including uranium enrichment, which unfortunately resulted in an avoidable fire at one of JAERI’s facilities.
In July 1967, in the aftermath of JAERI’s mounting troubles, the PNC was established by law, absorbing the AFC and all AFC responsibilities as well as JAERI’s principal mission of developing the ATR and FBR. The PNC reined over the Japanese nuclear R&D programs for over 30 years (1967-1998). The STA needed the PNC. It represented a new, more dynamic organization for promoting ATR and FBR development and gave STA the flexibility to direct JAERI to perform missions that were focused on advanced nuclear science research, including such things as fusion and synchrotron R&D and development of a nuclear-powered ship.
Given the breadth of STA’s big projects (See Table 1.1) the PNC quickly evolved into a research organization with major R&D responsibilities that included virtually the entire nuclear fuel cycle (Yoshioka, 2013). STA managed these projects for nearly three decades, laying the groundwork for the development of advanced nuclear technologies. (Details of individual projects are explained in subsequent chapters). Only nuclear power generation was outside of the PNC’s control.
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Table 1.1 The Power Reactor and Nuclear Fuel Development Corporation (1967-1998):
Organizations and Responsibilities PNC Organizations
Headquarters Business management, safety management, advanced reactor development, nuclear fuel cycle technology development, environmental technology development, nuclear fuel facility planning and management, international technology cooperation Tokai Works Operation of the spent fuel reprocessing plant, reprocessing
technology development, plutonium fuel development, advanced enrichment technology development, high-level radioactive waste disposal technology, FBR fuel recycling technology development Oarai Engineering
Center
Operation of the experimental FBR Joyo, R&D on FBR (plant engineering using full-size scale-models, safety engineering, equipment, material, fuel and material irradiation tests), nuclide annihilation treatment technology, new materials development
“Mutsu”
The One and Only Nuclear Ship in Japan
The Mutsu was Japan’s failed attempt to build a nuclear-powered ship for commercial purposes. It was built by JAERI. The ship was 130 m (430 ft) long, 19 m (62 ft) wide and 8,240 tons in weight, powered by a 36 MW Mitsubishi PWR and a 10,000 hp (7.5 MW). steam turbine. In November 1968, Ishikawajima-Harima Heavy industries started building the hull, which was launched in June 1969. Construction was completed in July 1969.
The Mutsu sailed to the Ominato harbor, Aomori Prefecture, which was its expected home port, arriving on 19 July. Nuclear fuel loading was completed by 6 June 1972 and the Mutsu departed Ominato to the open sea for testing purposes on 26 August 1974. (Tests could not be conducted pierside because of local protests). On 28 August 1974, the Mutsu achieved initial criticality and on 1 September, the crew raised power levels to 1.4%. At that point, neutrons and gamma rays were detected escaping through the reactor‘s shielding.
Westinghouse had reviewed the design and warned of this possibility, but no changes were made to the design.
This incident made national headlines and the residents of the Ominato community and the fishing industry refused to let the Mutsu return to the harbor. The ship underwent lengthy repairs from 1978 to 1982 at the port of Sasebo, Nagasaki prefecture. On 6 September 1982, Mutsu sailed once again to Ominato harbor and later to a new home port at Sekinehama, Aomori prefecture. At Sekinehama, the Mutsu’s containment vessel was opened and the ship completely inspected. The Mutsu departed Sekinehama in July 1990 for its first nuclear powered sailing. In October 1990, Mutsu achieved 100 percent of its rated power output. In February 1992, testing was completed. In March 1992, Japan decided to decommission the Mutsu. Japan had no plans to develop additional nuclear power commercial ships because of the lack of commercial viability, unless the ship is larger than hundreds of thousand tons, which would be extremely costly. The Mutsu project cost Japan more than $1.2 billion over 20 years (Nakao, no date; JAEA, 2018; Adachi, et. Al., 1995).
The Mutsu fiasco did have one lasting impact: it caused the government to revise its bureaucratic oversight of nuclear energy, shifting more responsibility to METI.
17 Ningyo-toge
Environmental Engineering Center
Operation of the uranium enrichment prototype plant, uranium refining and conversion technology development
Tono Geoscience Center
High-level radioactive waste underground disposal technology, uranium exploration and mining technology development, training of overseas engineers
ATR Fugen Power Plant
Operation of the ATR Fugen in Tsuruga, Fukui Prefecture FBR Monju Facility Construction of the FBR Monju in Tsuruga, Fukui Prefecture Tsuruga Facility (Fukui
Prefecture)
Operation and management of the ATR Fugen and FBR Monju and environmental safety management. This facility subsequently became the headquarters of the PNC’s successor, Japan Nuclear Fuel Cycle Development Institute (JNC).
Source: The table was created by the authors based on the graphics of the Research Institute of Industrial Science and Technology (RIST), 2003.
Serving as STA’s principal nuclear R&D organization, however, the PNC eventually became complacent in implementing safety measures across its many activities and became increasingly careless in its handling of fuel systems. By the 1990s, the PNC was “caught out” trying to hide mistakes and failures. It concealed facts, fabricated stories and even disregarded the nuclear regulatory agencies’ rulings and directives (See Table 1.2) (Ministry of Economy, Trade and Industry (METI), 2013). Worse, the PNC had become more accident-prone, making it fiscally difficult to sustain. Five accidents occurred under PNC stewardship, starting in 1995. This accident record, coupled with the PNC’s attempts in several cases to cover up accident details, eventually led to its demise:
(8 December 1995) Prototype FBR Monju Sodium Leak Accident. On 8 December 1995, the Monju FBR had a major sodium leak. The leak was non- radioactive and did not affect safety systems (reactor shutdown and cooling) but it did lead to a fire. It was rated as INES 1, a breach of operating limits at a nuclear facility and a deficiency of defense-in-depth (International Atomic Energy Agency (IAEA), no date; Federation of Electric Power Companies (FETC), no date). Worse, the PNC delayed accident reports, falsified the evidence, imposed gag orders on the workforce and covered up the seriousness of the accident, creating a public uproar (Sobajima, 1999; Ryall, 2010; Kondo, et al., 2013).
Moreover, a mid-level official assigned to conduct an internal investigation of the concealment of evidence of the sodium leak committed suicide. In the evening after he briefed the press, he was found dead, apparently having jumped from his 8th floor hotel room window (Research Organization for Information, Science and Technology (RIST), 2003).
(11 March 1997) Tokai Prototype Reprocessing Plant Accident. On 11 March 1997, a fire and explosion occurred at the PNC’s prototype reprocessing plant in Ibaraki Prefecture. The fire began in the radioactive liquid waste bituminization and storage facility at the
reprocessing plant. The fire was not properly extinguished and ultimately led to an
explosion that smashed windows and the release of radioactive smoke into the environment.
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The following day, workers used duct tape to repair windows and doors. At least 37 workers were internally contaminated with radioactive cesium and 10 billion becquerels or more of radio nuclides were released into the environment. Radioactive cesium released during the accident was detected in Tsukuba in the Tokyo suburbs, about 160 km from the Tokai-mura site (RIST, 2000; Wise-Paris, 1998). The plant operators delayed reporting the accident to the authorities, falsified the level of the radioactive leak, and destroyed
photographic evidence of the accident. (Dolley, 1999).
(14 April 1997) Tritium Leaks at ATR Fugen. In April 1997, the PNC discovered a tritium leak at ATR Fugen. The PNC delayed reporting the accident for 30 hours. Taking this delayed reporting seriously, the STA Director General ordered Fugen operations to cease the night of 15 April. Following the order, operators began to lower the power output at 10:30 pm. One minute later, the water level at the moisture separator started to rise, the turbine stopped automatically and Fugen shut down. Apparently, there had been a second tritium leak. It was later revealed that 11 similar accidents had occurred in the past, which had long been concealed. Also, at ATR Fugen, on 16 October 1997, about 2 cubic metersof radioactive coolant water leaked from a pressurized pipe during an inspection; on 5
November 1997, a similar accident occurred. It was found that the stainless-steel pipes that had been used since 1979 had cracks in them.
While not under the direct authority of the PNC, JAERI had an accident at a nuclear facility about the same time that other accidents occurred, fueling the public’s concern about the lack of adequate safety practices in managing nuclear material.
(20 November 1997) Fire at JAERI’s atomic steam testing laboratory. The fire occurred at the Tokai Uranium Enrichment Research Facility, Ibaraki Prefecture. The investigation found that metallic uranium became wet on 19 November while it was being removed from test equipment. The wet metallic uranium was put into two plastic bags and stored in one of 11 metallic cans. The cans were expected to be filled with inert gas the next day. At 1:15 am on 20 November, a fire alarm went off and the fire team found smoke at the stairwell adjacent to the laboratory. The fire was reported to the central security office, which reported the fire to the Tokai Fire Station in Tokai-mura. At the time of fire, the exhaust system in the testing laboratory was operating but soon became disabled due to clogged filters, thus filling the lab with smoke. The exhaust system was shut down and the filters were replaced. At 2:35 am on 20 November, JAERI officers and the Tokai-mura fire fighters entered the atomic steam testing laboratory. They found the fire had spread to 20 boxes that had been stacked and stored along with the 11 metal cans, containing burnable solid waste (wet waste, Tyvek suits, rubber gloves, etc.). The fire fighters used sand to extinguish the fire. It was subsequently reported that flammable gas had been generated from the wet metallic uranium and that the gas had ignited, creating the explosion. The exhaust dust monitor showed no radioactivity contaminants had leaked into the
environment and JAERI personnel and fire fighters’ radiation exposures were below minimum detection limits (RIST, 1998).
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Table 1.2 PNC, JAERI, JNC and JAEA10 Accidents and Consequences. Legend:
PNC in charge, listed by location and date JAERI in charge
JNC in charge, listed by location and date JAEA in charge, listed by location and date
Location Date Accident Misconduct or Error
FBR Monju in Tsuruga, Fukui Prefecture
December 1995
Sodium leak and fire To conceal the severity of the accident, PNC employees erased some accident scenes from one video tape and concealed the existence of another unabridged video tape, telling employees to hide the tape. Three executives were forced to resign. One employee who was assigned to investigate the tape concealment committed suicide.
September 2008
Corrosion holes in exhaust ducts
26 August 2010
Drop of In-Vessel Fuel Transfer Machine
Lack of robust testing and possible design flaw for the conduct of operations in a liquid sodium environment.
December 2010
Cracks in cylinder heads of diesel power generator
Not originally reported by operator September
2014
50 surveillance cameras out of order
Not originally reported by operator 2 March
2015
Discovery of deteriorated primary sodium cooling pipe systems
Nuclear Regulation Authority recommends JAEA be removed from operation of Monju FBR.
Tokai-mura reprocessing plant
11 March 1997
Fire and explosion at the bitumen waste facility. At least 37 workers were internally contaminated with cesium. Rated as an INES Level 3 accident.
PNC was the plant operator. Before the explosion, a report sent to the STA falsely stated that the fire had been extinguished. Photos taken by PNC workers were destroyed. PNC waited five hours before informing authorities of the radiation leak.
The first figures concerning the release of radioactivity during the accident were underestimated by a factor of ten to twenty.
10 The Japan Atomic Energy Agency (JAEA) was officially established in 2005.
20 ATR Fugen
in Tsuruga, Fukui Prefecture
14 April 1997
In the morning of 14 April, an alarm warned of a radioactive tritium leak.
The PNC found the leak adjacent to a circulation pump. Eleven workers were exposed to low-level doses of radiation.
PNC delayed the accident report by 30 hours.
15 April 1997
Learning of the delayed report, the STA Director General ordered the reactor to be stopped the night of 15 April. While the PNC was lowering the power level, the reactor shut-down because the moisture separator
signaled presence of a high level of moisture, which tripped the turbine, ending plans for a gradual shut down. The PNC then discovered a high level of heavy water in the
humidity separator from a second tritium leak.
During the following investigation, it was discovered that there already had been 11 similar incidents. Five managers of the PNC resigned.
16 October 1997
While inspecting a pressurized pipe, inspectors accidentally caused a leak of 2 cubic meters of radioactive cooling water.
Disconnection of pressurized pipe by inspection team was ill-advised.
5 November 1997
Stainless steel tube
connected to a heavy water drum was cracked, causing a leak.
Repeated flexing of tube caused the crack. Tube had been in use since 1979 and crack not found during inspections.
8 April 2002
About 200 cubic meters of steam escape from a defective pipe.
ATR Fugen was shut down and decommissioning approved in 2008. During dismantlement, it was discovered that walls with operational controls did not have the required strength at some 25 separate locations,
FBR Joyo, Oarai
October 2001
Fire at the Maintenance Facility.
The fire broke out in a maintenance building, where sodium was
removed from equipment and
21 Engineering
Center, Oarai, Ibaraki Prefecture
machinery repaired. There were no injuries or radiation leaks. No inspection since June 2000.
11 June 2007
The top of the irradiation test subassembly of the material testing rig, named MARICO-2, did not disconnect properly from its handling head; the rig and head were deformed as the rig was moved to its in-vessel storage rack. The deformation created an obstacle, preventing access to part of the reactor fuel.
The damage was discovered six months after it occurred, when the operator tried to replace fuel in November 2007. Moreover, six small pins from the top of the MARICO-2 were missing, which might have dropped to the bottom of the reactor. The sodium liquid in the reactor is not transparent, making it difficult to find the pins.
Tokai Uranium Enrichment Research Facility
20
November 1997
Flammable gas had been generated from the wet metallic uranium, which ignited, creating an explosion and fire.
No cited misconduct.
JCO
30
September 1999
Criticality accident. Two fatalities occurred due to inadequate training and flawed management of workers.
Plutonium Fuel Research Facility, Oarai R&D Center, Ibaraki Prefecture
8 June 2017 A bag containing plutonium and uranium inside a storage container broke, exposing five men to high levels of radiation.
Incident still under investigation, but preliminary reporting indicates lack of adequate training and safety protocols.
Sources: Table is based on authors’ interpretation and analysis of IAEA, no date; RIST, 2000;
Iwasaki, S., 2009.