Dry Cask Storage « nuclear-news

Fukui town mayor floats idea of dry cask storage for nuclear fuel

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FUKUI, Japan (Kyodo) — The mayor of a Fukui Prefecture town hosting a Kansai Electric Power Co. nuclear power plant where one of its reactors resumed operations just this month has floated the idea of installing dry cask storage within the plant and keeping ever increasing spent fuel there.

Takahama Mayor Yutaka Nose’s idea, though floated only as an option, is a rare one coming from someone in his position given that nuclear fuel is supposed to be moved out of a power station after it reaches the end of its usefulness after generating electricity.

At the same time, Nose has called for the central government’s greater involvement in projects to build temporary storage facilities for spent nuclear fuel outside nuclear power plants.

While Kansai Electric has said the site for its temporary storage facility to be built outside Fukui would be finalized sometime around 2020 and that the facility would begin being used around 2030, “there is no guarantee that (a municipality) outside the prefecture would agree to host the facility,” Nose said in a recent interview with Kyodo News.

But “it’ll be too late if we start thinking about (what to do with spent fuel) after (spent fuel pools) become full. We need to have a backup plan in case (the temporary storage project) goes nowhere,” he said.

Nose has effectively floated the option of building dry cask storage within the Takahama plant and keeping spent fuel there while at the same time continuing to use existing fuel cooling pools at reactors.

Dry cask storage, where spent fuel is kept in metal containers, “will reduce risks” of accidents, Nose said, on the grounds that such a storage method does not need water or electricity to keep spent fuel cooled.

In the 2011 Fukushima nuclear disaster triggered by a powerful earthquake and tsunami, reactors temporarily lost cooling functions in their spent fuel pools, putting a massive amount of fuel at risk of overheating and exposure.

“I’m responsible for the lives of town residents. Even if it is impossible to attain 100 percent safety, it is natural that we think about reducing risks. Not that we want to actively seek (spent fuel), but we have to think about the reality that (spent fuel) would remain in Takahama town,” he said.

The No. 4 reactor at the four-reactor Takahama plant resumed operations on May 17 amid persistent public concerns over the safety of nuclear power following the 2011 nuclear crisis. The plant’s No. 3 unit is scheduled to go back online in early June, while the remaining two units are expected to remain offline for the foreseeable future.

Cooling pools at the plant are capable of storing a total of 4,400 fuel assemblies but must be kept at less than capacity to allow for fuel exchange work. The pools collectively have about 2,700 assemblies already. If all four reactors begin operating there, the pools will reach their capacity within six to seven years.

https://mainichi.jp/english/articles/20170528/p2g/00m/0dm/052000c

May 29, 2017 Posted by dunrenard | Japan | Dry Cask Storage, Nuclear Fuel, Takahama Mayor, Takahama NPP | Leave a comment

NRA pushing dry cask storage, not pools, for spent nuclear fuel

Japan’s nuclear watchdog will ease quake-related and other regulations on storing spent fuel to push the use of dry casks and reduce the dangers stemming from power failures at nuclear power plants.

The Nuclear Regulation Authority decided on Jan. 25 that utilities should place spent nuclear fuel in the special air cooling containers instead of the common practice of submerging the fuel rods in pools of water.

Fuel stored in pools is cooled by circulating water with pumps, but the system can shut down if earthquakes and other disasters cut off the power supply. The water could then evaporate, leaving the spent fuel and radioactive substances exposed to air.

Electric power companies have shown a positive attitude toward the dry storage system because it would enable them to keep more spent fuel when the pools are filled close to capacity.

However, municipalities that host nuclear power plants have expressed strong concerns that the system will let utilities keep spent nuclear fuel at plant sites for prolonged periods.

NRA Chairman Shunichi Tanaka stressed the need for safety.

“It (dry cask storage) is much safer than storing fuel in pools,” he said.

The Great East Japan Earthquake and tsunami cut off power to Tokyo Electric Power Co.’s Fukushima No. 1 nuclear plant in March 2011. Three reactors melted down, and the cooling system would not work for more than 1,000 spent fuel assemblies in the pool in the No. 4 reactor building.

Fears arose that all water in the pool could evaporate. But emergency measures, including the pumping in of water, were taken to keep the fuel submerged.

Under the dry storage system, the fuel is sufficiently cooled in pools and placed in dedicated airtight cases. The special casks are then stored inside air-permeable facilities.

The NRA plans to promote use of casks that are currently used to transport spent nuclear fuel.

The containers have passed durability tests and can withstand falls from a height of 9 meters and high-temperature fires.

Dry storage containers are widely used in the United States and Europe.

But the use of dry casks has not spread in Japan because of the high hurdles that must be cleared. One requirement is that those containers must be stored in building that can withstand the strongest earthquake predicted in the area.

As a result, dry storage containers are used at only a few nuclear facilities in the country, such as Japan Atomic Power Co.’s Tokai No. 2 nuclear power plant in Ibaraki Prefecture.

According to the Federation of Electric Power Companies of Japan, a total of 15,000 tons of spent fuel is stored at 17 nuclear plants across Japan.

Seventy percent of their fuel pools and other storage facilities have been filled with spent fuel.

http://www.asahi.com/ajw/articles/AJ201702140004.html

February 14, 2017 Posted by dunrenard | Japan | Dry Cask Storage, NRA, Spent Nuclear Fuel | Leave a comment