Mitsubishi Heavy Industries shipped reactor vessel head to U.S. NPP

Neutron flux detector containing highly enriched uranium lost

Confidential nuclear information posted on internet

Initial Safety Assessment for Ohma reactor Completed

People entered Tomari NPP to gather bamboo-shoots

As active trials at the Rokkasho reprocessing plant approach (scheduled for December this year), electric power companies are under pressure to give details of their pluthermal plans¹. In June Chugoku Electric Power Company was preparing to submit a request to local governments for an expression of 'prior understanding' regarding the implementation of pluthermal at Shimane 2 (BWR, 820 MW). On June 9th the company conveyed its intention to Shimane Prefecture and Matsue City, but on the 17th it was revealed that the flow of water increased around a mechanical seal in the reactor's recirculation pump, and on the 18th the reactor was manually stopped. After changing the seal, power generation was resumed on the 28th, but submission of a request for prior understanding was postponed.

While Shimane Prefecture appears likely to accept the plan, the Mayor of Matsue City is adopting a more cautious attitude. The Shimane nuclear power plant is located in Kashima Town, but Kashima was merged with other towns into Matsue City, making the Shimane nuclear power plant the only NPP that is located in a prefectural capital.

1. 'Pluthermal' refers to the use of MOX fuel (mixed oxide of plutonium and uranium) in light water reactors.

On June 27th, Mitsubishi Heavy Industries, Ltd. (MHI) shipped a replacement reactor vessel head, which had been ordered by Alabama Power Company for the Joseph M. Farley No. 2 reactor (PWR, 839 MW). Since 2002, MHI has received several orders from the U.S. for replacement reactor vessel heads for Westinghouse PWRs. This latest one was the 10th.

On June 24th it was revealed that a small neutron flux detector missing at Kansai Electric Power Company's (KEPCO) Takahama-3 reactor (PWR, 870 MW). The instrument is about 5 cm long and 5 mm in diameter. 1.7 mg of highly enriched uranium is painted onto the inside of the instrument. It was purchased in January 2003. Due to a problem with the cable, it had been stored unused with the tip cut off. It is highly possible that it was discarded when a new one was purchased, as it had been put in a polyethylene bag for uninflammable radioactive waste. KEPCO is now looking for the missing instrument, checking drums of radioactive waste.

On June 23rd the Mainichi Shimbun reported that a large quantity of information had been posted on the internet from a virus infected PC used by an employee of a Mitsubishi Electric Corporation subsidiary. The company was contracted to undertake inspections at both nuclear and thermal power plants. It seems that the leak occurred through the Winny file-swapping program which, when infected by a certain virus, uploads files to the internet. Apparently the leaked information did not include information related to the protection of nuclear materials, but it did contain reports on regular inspections, including photos of the inside of plants and lists of names of workers. There were also e-mail messages discussing how to conceal problems at a thermal power plant from the electric power company.

Mitsubishi Electric (along with other companies) had only just declared a corporate security control pledge. The pledge was made in February this year.

(Stop Press: another similar incident occurred just as NIT 107 was going to press. Again the leak seems to have occurred through the Winny program, but this time the leak came via a virus infected PC belonging to a worker at the Nuclear and Industrial Safety Agency. Newspaper reports suggest that the contents of the leak were similar to the previous leak.)

The Nuclear and Industrial Safety Agency (NISA) completed the initial safety assessment for the Ohma reactor (ABWR, 1,383 MW) on June 16th. J-Power plans to construct the reactor in Ohma Town, Aomori Prefecture. Stating that it had found no safety problems, NISA submitted a request to the Nuclear Safety Commission for a double check. The Ohma reactor is the only reactor for which it is planned to use MOX fuel in the entire core. It is also the only nuclear power plant where a portion of the land in the reactor site remains unsold. (There are other similar cases where the reactors are still in the planning stage and the safety assessment process hasn't yet started.) A parcel of land has not been sold in protest against the construction.

Since 9.11, Japan too has strengthened security measures at nuclear power plants. Riot police with automatic weapons are stationed at all of Japan's NPPs. Staff of private security companies patrol the sites and guard the entrances. At sea the Japan Coast Guard's patrol boats guard the surrounding area. All of this is carried out on a round-the-clock basis.

Neverthess, it emerges that in May both this year and last year people broke into the Hokkaido Electric Power Company's Tomari nuclear power plant (two PWRs, 1,158 MW in total), climbing over the 2.5-meter high barbed-wire fence to gather bamboo shoots and other edible wild plants. As a result of this year's break in, 24 people have been charged with trespass. Though not confirmed, it is hard to believe that there haven't been other break-ins of this nature.

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