Blackout - Cooling restored to SFP nos.1 & 4

March 19, 2013

UPDATE: Cooling systems restart for 2 spent fuel pools at Fukushima nuclear plant

http://ajw.asahi.com/article/0311disaster/fukushima/AJ201303190020

THE ASAHI SHIMBUN

The cooling systems restarted for spent fuel pools in the No. 1 and No. 4 reactor buildings at the crippled Fukushima nuclear plant on March 19, although operations for other facilities remained suspended.

The shutdown of cooling systems occurred after a power outage around 7 p.m. on March 18 in the main quake-resistant building at the Fukushima No. 1 plant, Tokyo Electric Power Co., the plant’s operator, said.

Power has been restored, and cooling operations for the spent fuel pool for the No. 1 reactor resumed at 2:20 p.m., the Nuclear Regulation Authority said.

The cooling system for the spent fuel pool in the No. 4 reactor building resumed at 4:13 p.m., TEPCO said.

But by late afternoon on March 19, the cooling systems were still not operating for the spent fuel pool in the No. 3 reactor building and a common fuel pool. A radioactive water decontamination system and several other facilities were also not running.

TEPCO earlier said it planned to confirm the cause of the problem and have all cooling operations restarted on March 19. It is considering supplying electricity to cooling systems from a different source.

The company said the power outage was likely caused by a defect in a temporary switchboard for the No. 3 and No. 4 reactors.

The utility said the cooling facilities for the nuclear reactors were operating normally, and monitoring posts have shown no changes in radiation levels in the area.

The spent fuel pools in the No. 1, No. 3 and No. 4 reactor buildings together hold 2,491 fuel assemblies. The common pool stores 6,377 fuel assemblies.

The temperature of the water in the No. 4 reactor’s pool had climbed to 31.6 degrees at 1 p.m.

Industry minister Toshimitsu Motegi told TEPCO to restore the operations as soon as possible. He also scolded the company for the delay in disclosing the latest problem at the stricken nuclear plant.

TEPCO announced the power outage more than three hours after it occurred.

“We thought we had better make a report after confirming and summarizing the situation at the facilities,” a TEPCO official said. “We are extremely sorry because it took us so long.”

At the Fukushima No. 1 plant, cooling systems for spent fuel pools were suspended in the No. 3 reactor building in July 2011, in the No. 2 and No. 3 reactor buildings in January 2012 and in the No. 4 reactor building in June 2012 due to a blackout and other reasons.

Fukushima urges TEPCO to restore cooling

      http://www3.nhk.or.jp/daily/english/20130319_30.html

Fukushima Prefecture has asked Tokyo Electric Power Company to restore the cooling system at its Fukushima Daiichi nuclear power plant. The cooling system was suspended after a momentary power outage on Monday evening.

Fukushima Prefecture sought an explanation of the problem from 2 TEPCO officials on Tuesday morning.

An official of Fukushima Prefecture, Shoji Furuichi, said TEPCO had not yet identified the cause of the trouble, fueling concerns among local residents.

He also asked the utility to ensure safety by installing multiple power-generation units at the plant and to step up its monitoring system so similar problems can be detected in their early stages.
He also asked TEPCO to swiftly provide residents with information on any problems that arise at key facilities and explain their estimated impact and risks in an easy-to-understand way. This time, the power outage was made public 3 hours after it took place.

A university student in Fukushima city said the delayed announcement, as well as the outage itself, causes her serious concern, as such delays could seriously affect residents if the situation required them to evacuate.

A company employee in his 60s said he is concerned that the prolonged outage could affect cooling operations at the plant, which is still storing a number of fuel rods.

Mar. 19, 2013 - Updated 10:10 UTC (19:10 JST)

Cooling restored at 2 Fukushima reactors

http://www3.nhk.or.jp/daily/english/20130319_27.html

Tokyo Electric Power Company says it has restored cooling systems for spent fuel pools at 2 of 3 reactors affected by a power failure at the damaged Fukushima Daiichi nuclear power plant.

The momentary power failure just before 7 PM on Monday suspended cooling systems for the No. 1, 3 and 4 reactors as well as a shared pool for spent fuel in the plant's compound.

TEPCO officials later found that 3 power distribution boards had stopped working. The utility repaired two of the boards, but could not fix the third and instead used an emergency power generator to restore the cooling system for the No. 4 reactor's fuel pool.

As a result, the cooling system for the No. 1 reactor's fuel pool resumed functioning around 2:20 PM on Tuesday, 19 hours after the power failure. The No. 4 reactor cooling system restarted after 4 PM.

TEPCO plans to restore the cooling systems for the No. 3 reactor by around 8 PM on Tuesday, and for the shared pool by around 8 AM on Wednesday.

The firm continues to investigate what caused the boards to stop functioning. It says they do not appear damaged.

TEPCO says the temperature of the No. 4 pool was 25 degrees one hour before the power failure. The temperature rose to 30.5 degrees Celsius at 10 AM on Tuesday. TEPCO says the level does not affect cooling as it is below the safety threshold of 65 degrees.

The firm says the power failure did not affect water injection to the No. 1, 2 and 3 reactors. They suffered core meltdowns in the early days of the nuclear crisis triggered by the March 11th, 2011 quake and tsunami.

The utility also says no change has been observed in radiation levels at monitoring posts around the plant.

Mar. 19, 2013 - Updated 09:33 UTC (18:33 JST)

Fukushima plant's spent fuel pool cooling system partially restored

http://mainichi.jp/english/english/newsselect/news/20130319p2g00m0dm064000c.html

TOKYO (Kyodo) -- Tokyo Electric Power Co. said Tuesday it has partially restored 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.

As for the spent fuel pool located atop the damaged No. 4 reactor building, one of the two lines forming the cooling system was restored at around 1:20 p.m. Tuesday. The other line is expected to resume operation at around 8 p.m., the utility said.

The cooling system for the No. 1 spent fuel pool was also put back online at 2:20 p.m.

During a press conference in the morning, TEPCO spokesman Masayuki Ono said it is placing the "highest priority" on restoring the cooling system of the No. 4 spent fuel pool, as the number of fuel assemblies stored in the tank is larger than those left in the pools of the Nos. 1, 2 and 3 units.

Ono also said the water inside the pools is still "sufficiently cool," with the temperature of the pools at the No. 1, 3 and 4 reactors estimated to be between 15.9 C and 30.5 C as of 10 a.m. The upper limit TEPCO has set to secure safety during ordinary times is 65 C.

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

Economy, Trade and Industry Minister Toshimitsu Motegi said at a press conference 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."