Plutonium intended to fuel Japan's prototype fast-breeder nuclear reactor, shut down after a leak from its cooling system, could be used at other Japanese reactors instead, the fast-breeder operator said on Monday. "It is possible that plutonium intended for the fast-breeder could be used at other reactors," said a spokesman for governmental Power Reactor and Nuclear Fuel Development Corp (PNC), which runs the fast-breeder.
"However, it is too early to discuss whether plutonium will be used at other reactors when we are still investigating the cause of the accident, and do not know how long the fast-breeder will be closed," he said.
The high-quality plutonium needed for the fast-breeder, known as Monju, degrades if stored for too long, he said.
"Roughly speaking, plutonium stored for two to three years, deteriorates to an extent it cannot be used," he said.
The Kyodo news agency said more than 500kg (1,100 pounds) of plutonium could be used at an experimental fast-breeder reactor in Oharai, Ibaraki Prefecture, and a prototype heavy-water reactor in Tsuruga, Fukui Prefecture, instead of Monju, because of an indefinite shutdown of operations there.
>>The Kyodo news agency said more than 500kg (1,100 pounds) of plutonium could be used at an experimental fast-breeder reactor in Oharai, Ibaraki Prefecture, and a prototype heavy-water reactor in Tsuruga, Fukui Prefecture, instead of Monju, because of an indefinite shutdown of operations there.<<
Some of the plutonium fuel shipped back to Japan from France after reprocessing was already shipped as MOX-fuel (a mixture of plutonium oxide and uranium oxide) for use in Japanese commercial Light Water Reactors (LWR). This was because of the late startup of the Monju Fast Breeder Reactor (FBR) that was orignally supposed to use all that plutonium. Now that Monju may be out of action for several months to two years even the remaining undiluted plutonium is going to become unusable as FBR fuel before it can be used up: Plutonium from LWR waste "ages" through radioactive decay of its impurities and that makes it unusable for fuel in a FBR like Monju within about 2 or 3 years.
This is putting the PNC, the Japanese governmental corporation that operates Monju, into a tight spot: Japan already has about 30 tons of plutonium extracted from its nuclear waste and without Monju (which at any one time has about 1600 kg of that substance in its core) it will not be able to use it up as intended. The alternative is to convert it into MOX fuel for LWRs, but there are problems with that appoach too.
For one, the plutonium destined for Monju was not diluted with uranium, hence has to be processed before it can be used as LWR fuel. The fact that Japan paid France to process plutonium into MOX before shipment suggest that Japan does not have the necessary facilities to do that. In that case the PNC will either have to construct an MOX fuel factory or it may have to ship the plutonium back to France, have it processed there again and have it shipped back to Japan once more. There are also commercial facilities in the US that could do the job.
Secondly, using plutonium from LWR waste as LWR fuel is economic madness: It is far more expensive to make MOX fuel from recycled plutonium than it is to buy fresh uranium from American, Canadian or Australian mines. Economically it's like burning dollar bills to heat your house. The expensive extraction of plutonium from nuclear waste (current reprocessing contracts with BNF in the UK and the French plant in Cap La Hague are worth several billion dollars to those companies) was justified primarily with the need to have a plutonium breeding stock for Monju and its successors, to make Japan independent of nuclear fuel imports in the future. If Monju is not able to make use of the plutonium there is no need to keep extracting it from waste. The money on the reprocessing contracts would be better spent on stockpiling cheap imported uranium, but that would also turn the new reprocessing plant under construction in Rokkasho, Aomori pref. (price tag: about $6 billion, company in charge: PNC = Monju's operators) into an expensive ruin before 1998, when it's scheduled to be completed. When Germany decided not to start up its key-ready SNR-300 FBR in Kalkar near the Dutch border after the economic realities of plutonium had changed beyond recognition, it also canned its plans for the corresponding reprocessing plant, even though it had been under construction for two years and over a billion dollars had already been spent. The PNC is fighting so hard for Monju because without Monju it will also lose Rokkasho.
If some use for the plutonium is not found soon that would put some of the most prestigious projects of the PNC into question, so it is thinking hard and fast. Using the plutonium in the experimental FBR in Ibaraki prefecture sounds OK on paper but is completely pointless: That reactors was actually the precursor to Monju, the testbed for developing all of Monju's technologies but at a smaller scale and unable to breed more plutonium than it burns. With Monju's startup that plant had become obsolete already. Keeping it running using Monju's fuel is merely a face saving device to distract from the fact that without Monju there will no longer be a reason to keep making plutonium.
DAILY NEWS, 26. Dezember 1995
Japanese nuclear experts on Tuesday found fault with plant design, warning systems and operating manuals behind the recent accident at a prototype nuclear reactor. "There are serious faults with basic issues at the plant, issues which are indispensable in winning residents' trust in nuclear power," said the interim report issued by nuclear power safety officials of the Fukui prefectural government. Fukui prefecture houses 13 of Japan's 49 commercial nuclear power plants and also accommodates the prototype fast-breeder reactor Monju on the Sea of Japan coast and a prototype advanced thermal reactor nearby.
(to be continued)