Blackout March 19 - Mainichi

Fukushima nuclear plant's fuel pool cooling system still suspended

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TOKYO (Kyodo) -- Tokyo Electric Power Co. remained unable as of Tuesday morning to resume the cooling system for the spent fuel pools of the No. 1, 3 and 4 reactors at the crippled Fukushima Daiichi nuclear power plant, which has been suspended since Monday evening due to a suspected problem with a power switchboard.

The incident has not affected the injection of water into the Nos. 1, 2 and 3 reactors that suffered core meltdowns in the early days of the nuclear crisis at the plant triggered by the March 2011 earthquake and tsunami.

TEPCO spokesman Masayuki Ono said it is placing the "highest priority" on restoring the cooling system of the spent fuel pool located atop the No. 4 reactor building, as the number of fuel assemblies stored in the tank is larger than the heavily damaged Nos. 1, 2 and 3 units.

Ono also said the water inside the pools is still "sufficiently cool," with the temperature of the three pools estimated to be between 15.9 C and 30.5 C as of 10 a.m. Tuesday.

It is expected to take about four days until the temperature of the water inside the No. 4 spent fuel pool reaches 65 C, the upper limit TEPCO has set to secure safety during ordinary times, according to the utility.

Ono said the utility is prepared to inject water into the spent fuel pool at any time necessary if the water in the pool warms up and starts to decrease by evaporation.

TEPCO noticed the trouble after electricity instantaneously went out at the plant's accident response center at 6:57 p.m. Monday.

The company currently suspects that a problem at one makeshift power switchboard is causing the suspension of the cooling system.

Economy, Trade and Industry Minister Toshimitsu Motegi told a separate press conference in the morning that he has instructed TEPCO to take every possible measure to address the problem at the plant.

At another press conference, Chief Cabinet Secretary Yoshihide Suga said, "We will make utmost efforts to prepare alternative methods to cool the pools in consideration of a worst-case scenario."

Fukushima residents irked by outage at crippled atomic plant

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FUKUSHIMA, Japan (Kyodo) -- Residents of Fukushima Prefecture expressed anxiety about an outage hit the disaster-damaged Fukushima Daiichi nuclear power plant on Monday.

Masahide Matsumoto, mayor of Katsurao village where all of its residents have been forced to evacuate after the March 2011 nuclear disaster, said that the incident came at a sensitive time as evacuation zones are scheduled to be reclassified Friday and some residents are allowed to make day trips to their homes.

"We will be in trouble unless Tokyo Electric Power Co. properly investigates the cause (of the outage) and restores power," Matsumoto said, citing concerns for increased worries among villagers.

A 27-year-old housewife in Fukushima City said,

"I am very worried because I have a baby. I want the information to be disclosed as quickly as possible because it will be difficult to evacuate promptly if (an emergency occurs) at night." The incident was made public by the Nuclear Regulation Authority around three hours after it took place just before 7 p.m.

A 49-year-old office employee in the city, Takashi Haga, seemed surprised at the latest incident, saying, "It revived the memory of the nuclear accident two years ago. I thought it was under control."

At the Fukushima prefectural government office, four staff members at a nuclear safety division received information by fax or phone from TEPCO and communicated with officials at local municipalities. The staffers appeared relatively calm, with one of them saying, "We want TEPCO to pin down the cause and respond to the situation."

Makoto Yanagida, a representative of the antinuclear civic group No Nukes Plaza Tokyo known as Tanpoposha in Japanese, said, "It's just nonsense that a power company is hit by a blackout. We need to be vigilant, though, to see if TEPCO is going to make public what really happened."

Fukushima nuclear power plant suffers outage, fuel pool cooling stops

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TOKYO (Kyodo) -- Tokyo Electric Power Co. said a power failure occurred at the crippled Fukushima Daiichi Nuclear Power Station just before 7 p.m. Monday, leading to the suspension of systems to cool spent fuel pools of the No. 1, 3 and 4 reactor units.

The incident so far has not affected the ongoing water injection to the Nos. 1 to 3 reactors, which suffered core meltdowns in the early days of the March 2011 nuclear crisis, according to the Nuclear Regulation Authority. No major changes have been observed in radioactivity levels detected by nearby monitoring posts.

As of 1:45 a.m., TEPCO has not been able to work out steps to ensure bringing the system back online. The accident response center at the station also suffered outage but power was restored shortly.

The electricity trouble has also led to suspended operation of equipment for treating contaminated discharge including radioactive materials, as well as a cooling system at another pool located inside a different building which contains 6,377 fuel assemblies.

TEPCO, nor the NRA, has been unable to pin down the cause of the outage, although the power company said it could have stemmed from the power distribution board or cables attached to it.

It took until just past 10 p.m., or around three hours, for TEPCO to make an announcement on the blackout. TEPCO said, "There were too many points to inspect and had trouble confirming with those on the site."

According to the NRA, TEPCO reported to regulators that electricity went out at the plant's accident response center at about 6:57 p.m. Monday.

The temperatures of the water inside the spent fuel pools of the Nos. 1-4 units were between 13.7 C and 25 C at 4 p.m. Monday said.

If no steps are taken to cool down, the temperature of the water inside the spent fuel tank at the No. 4 unit, which has posted the highest temperature, would reach 65 C -- the upper safety margin limit TEPCO has set -- within four to five days, the power company said.

The No. 4 spent fuel pool, located atop a building damaged by a hydrogen explosion, stores a total of 1,533 fuel assemblies.

The cooling system of the fuel pool at the No. 2 unit had been suspended for electrical work since Monday morning but resumed operating at just past 6:30 p.m.

The power station also suffered temporary suspension of the cooling mechanism for spent fuel pools at the Nos. 1-4 units in January last year. In June, cooling of the fuel pool at the No. 4 unit was suspended for around 30 hours and the water temperature in the pool temporarily rose to around 43 C.