TOKYO -- The Japanese government plans to encourage utilities to store spent nuclear fuel in containers cooled by air instead of in pools of water, a technique whose flaws were exposed by the Fukushima Daiichi nuclear plant accident, The Nikkei learned Thursday.
The use of pools at nuclear plants to cool spent fuel, which produces a large amount of heat, is considered a temporary measure. Original plans called for the radioactive material to be reprocessed at a plant in Rokkasho, Aomori Prefecture, but problems have nullified the prospects of this facility going onstream. As a result, as they prepare to restart their nuclear plants, utilities face the need to increase storage capacity.
Dry cask storage involves taking spent fuel that has been cooled for about a year in pools and sealing it in metal or concrete containers called casks, which are then stored inside buildings. When the 2011 earthquake and tsunami struck the Fukushima nuclear plant, spent fuel lying in pools could no longer be cooled due to the loss of power. Dry cask storage facilities, however, were not damaged by the tsunami.
But because this technique is safer, local governments are likely to become concerned that spent fuel could be stored indefinitely if they host such facilities. The Ministry of Economy, Trade and Industry plans to revise the grants paid to municipalities to encourage them to accept the responsibility. Currently, local governments receive 400,000 yen ($3,880) for each ton of fuel they store, regardless of method. The ministry is considering paying more for dry cask storage starting in fiscal 2016.
The operating costs for this method are said to be about 60% lower than pool storage. The U.S. stores roughly 70,000 tons of spent fuel at about 80 dry cask storage sites, and Germany is also building such facilities. But Japan currently has just two sites storing 240 tons combined, or roughly 1% of the total amount of spent fuel in the country.
Amid expectations that nuclear plants will resume operations in the near future, the fact that pools at nuclear plants nationwide are nearing capacity is another factor behind the change. A panel of experts formed Thursday is to hammer out the specifics, possibly by the end of the current fiscal year.