News Watch 124 (May/June 2008) Nuke Info Tokyo No. 124
Request for Hearings on Pluthermal for Tomari-3
On April 18, Hokkaido Electric Power Company requested the prior approval of Hokkaido Prefecture, Tomari Village and the surrounding two villages and one town for its pluthermal plan for Tomari-3 (PWR, 912 MW). Tomari-3, which is currently under construction, is due to commence commercial operations in December 2009. This is the first time that such a request has been made for a reactor under construction.Considering that the MOX fuel will not be manufactured until after local approval is received, the safety assessment is completed and central government approval is obtained, it will not be possible to load MOX fuel during the first reload, which is planned for January 2011. It is more likely that MOX will not be loaded until the second reload, which is expected to occur in February 2012.
Manufacture of MOX Fuel for Ikata and Hamaoka Begins
Manufacture of MOX fuel for Ikata-3 (PWR, 890 MW) began on April 23 at the Melox Plant in France. Shikoku Electric Power Company entered into a contract with Mitsubishi Heavy Industries (MHI) for the supply of MOX fuel. MHI subcontracted the work to Melox, which will manufacture 21 fuel assemblies containing 0.6 tons of plutonium. Shikoku Electric aims to implement pluthermal* by Fiscal Year 2010.Manufacture of MOX fuel for Hamaoka-4 (BWR, 1137 MW) began on May 7, also at the Melox Plant. Chubu Electric signed a contract with Global Nuclear Fuel Japan (GNF-J) for the supply of 48 MOX fuel assemblies. GNF-J subcontracted fabrication of the fuel to Melox. Chubu Electric also plans to implement pluthermal by FY 2010.
* The term ‘pluthermal’ refers to the use of plutonium in the form of mixed oxide fuel (MOX) in ‘thermal’ – as opposed to ‘fast’ – reactors.
Applications Called to Host TRU Waste Dump
A legal amendment passed last year allowed TRU waste (transuranic isotopes, and other long-lived isotopes, such as iodine-129 and carbon-14) arising from reprocessing, MOX fuel fabrication plants, etc. which are destined for geological disposal to be disposed together with high-level radioactive waste (HLW). On April 2, the Nuclear Waste Management Organization (NUMO), which has been trying to find a site for HLW, began calling for applications to host a waste dump for TRU as well. From now on NUMO will be seeking applications to host three types of waste dumps: 1) HLW only, 2) TRU only, and 3) HLW and TRU.The radiation on the surface of TRU waste containers is higher than for HLW in an “overpack”, it will begin to leak sooner, and is more likely to be released into the environment. Furthermore, if TRU and HLW dumps are collocated, they will mutually affect each other to increase the likelihood that both TRU and HLW will be released into the environment.
Various Computer Programming Errors
On April 8, Japan Nuclear Fuel Ltd (JNFL) announced that it would amend data relating to surface radiation on 13,916 drums of waste received at its Rokkasho Low-Level Radioactive Waste Disposal Center between FY1993 and FY2007. It said that the original data was incorrect. In January an error was discovered for drums received from Kansai Electric Power Company’s Mihama Nuclear Power Plant. When data from other NPPs were checked, errors were discovered for Chugoku Electric’s Shimane NPP, Shikoku Electric’s Ikata NPP and Japan Atomic Power Company’s Tsuruga NPP. The errors were due to a programming mistake by the manufacturer (the same company for all except Mihama). In each case the recorded figures were 1% lower than they should have been. There were other errors, but because the figures had been rounded, no change was required. JNFL claimed that even after the figures were corrected, the benchmarks were not exceeded.Also on April 8, Tokyo Electric Power Company (TEPCO) announced that alpha radiation detected on April 2, during a periodic measurement for the exhaust pipe of an incinerator building at its Kashiwazaki-Kariwa NPP, was one hundred thousand times lower than it should have been. The mistake was discovered when alpha radiation was detected again on April 8. The mistake was caused by an error in the alpha radiation calculation formula entered into the operating software. In this case too, TEPCO claimed that the figure was still under the benchmark, even when multiplied by a hundred thousand.
Again on April, 8 in this case the computer programming error related to calculation of the strength of pipes owned by six power companies and Japan Atomic Energy Agency. Because the weight of the pipes at 16 NPPs and the Monju Fast Breeder Reactor was not entered into the calculation, the stress was underestimated. The program was produced by Hitachi in 1980, meaning that the mistake was not discovered for nearly 30 years. Of course, the companies assure us that the results of the recalculation confirm the pipes’ safety.
One wonders how many other such errors remain.
MHI and Areva to Cooperate on Fuel Cycle
On April 11, Mitsubishi Heavy Industries (MHI) and Areva reached a basic agreement on a cooperative project related to the nuclear fuel cycle. The focus of the business is supply of a wide variety of nuclear fuel, such as fuel for PWR and BWR, including MOX fuel, and fuel for High Temperature Gas Reactors. MHI plans to invest in an Areva-owned Virginia USA fuel fabrication company. It appears that they are also considering establishing a joint company in Japan.Meanwhile, Toshiba is trying to take over Nuclear Fuel Industries Ltd (NFI) in order it to gain the ability to supply PWR nuclear fuel. To this end, it is applying pressure to NFI’s parent companies, Furukawa Electric Co. Ltd. and Sumitomo Electric Industries Ltd.. It appears that Mitsubishi Heavy Industries is responding by attempting to take over NFI itself.
Red Light for Autumn Restart of Monju
It seems that there is no chance of restarting Monju (Prototype FBR 280 MW) in October as planned. Numerous defects have been discovered in the installation of sodium leak detectors. By the end of April, 24 detectors with deformed tips had been discovered. Atsuyuki Suzuki, Chairman of the Nuclear Safety Commission (NSC), said on April 17 that the incident must be taken seriously. He said, “The incident seems to have common causes with the sodium leak accident in 1995.” He also strongly criticized the delayed response of the Japan Atomic Energy Agency and admitted, “The NSC cannot hand off the situation, because the NSC also reviewed the regulatory activities. “Meanwhile, on April 26 Fukui Prefecture and Tsuruga City gave their prior consent for the initial fuel load replacement plan**, indicating their intention to cooperate with the restart of the reactor.
** Replacement fuel is required to replace degraded old fuel (see NIT 123).