ID :
184713
Thu, 05/26/2011 - 18:28
Auther :
Shortlink :
https://oananews.org//node/184713
The shortlink copeid
TEPCO continued seawater injection at reactor without interruption
TOKYO, May 26 Kyodo - Tokyo Electric Power Co. said Thursday it had continued injecting seawater into its No. 1 reactor at its crisis-stricken nuclear plant in Fukushima Prefecture, reversing its earlier story that it had suspended the work after receiving information that the prime minister's office was concerned about it.
The utility, known as TEPCO, said it learned of the move after questioning the head of the Fukushima Daiichi nuclear power plant, who told company officials this week that he had gone ahead in continuing seawater injection into the No. 1 reactor despite the firm's decision to suspend the work.
TEPCO had earlier said it began injecting seawater to cool nuclear fuel inside the reactor on the evening of March 12, one day after the magnitude 9.0 earthquake and tsunami, but that it suspended the work 21 minutes later before resuming it another 55 minutes afterward.
A crisis management office consisting of government and TEPCO officials had said the initial injection was suspended after the prime minister's office conveyed its concern that seawater injection could cause fuel rods to resume fission, a phenomenon otherwise called ''recriticality.'' The work was resumed after Prime Minister Naoto Kan gave a directive for the seawater injection, according to the office.
TEPCO said the plant chief, Masao Yoshida, had thought it safer to continue injecting the seawater to prevent the crisis from worsening, adding that the latest finding came to light during its questioning of him between Tuesday and Wednesday. TEPCO conducted the questioning after the issue became a focus of attention in Diet deliberations, it said.
''I decided to report the facts because of a probe conducted by the International Atomic Energy Agency and because various international appraisals are forthcoming,'' Yoshida was quoted by a TEPCO official as telling the company.
While defending Yoshida's decision to continue injecting seawater as ''technically reasonable,'' TEPCO's Vice President Sakae Muto said at a news conference that his company is considering punishing Yoshida for not promptly reporting the facts.
Chief Cabinet Secretary Yukio Edano criticized TEPCO for the latest turn of events, telling a separate news conference, ''The public will harbor mistrust unless facts are reported accurately.''
Seawater injection was deemed necessary to cool fuel inside the reactor after the injection of fresh water stopped in the aftermath of the quake and tsunami, which knocked out key cooling systems at the plant.
Earlier Thursday, TEPCO said the level of highly radioactive water at a temporary water storage building had dropped by around 5 centimeters after the liquid was diverted from elsewhere at the plant.
The utility then found that the water appears to have seeped into a corridor that connects the building and another at the plant's same nuclear waste disposal facility, it said, adding the water was about 2 meters deep.
While the utility has not detected unusual levels of radioactive substances in nearby groundwater, it will increase the number of sampling spots for groundwater and beef up its surveillance, because the water leakage into the environment could affect the company's overall plan to remove contaminated water from reactor-related facilities to enable work inside them.
The operator stopped transferring the contaminated water from the No. 3 reactor's turbine building to the storage building at 9 a.m. Wednesday as the total amount of water came close to a planned limit.
It stopped transferring similar water to another building at the same facility from an underground tunnel near the plant's No. 2 reactor on Thursday for the same reason.
While the amount of diverted water from the two spots has already reached the planned limit of around 14,000 tons, TEPCO said Wednesday that an additional 5,000 tons of contaminated water could be transferred there.
At the power plant, water has been pumped into reactors to cool the fuel inside them since their cooling systems were disabled. The water is suspected of leaking into reactor-housing buildings and facilities nearby due to ruptures in reactor pressure vessels and the containment vessels encasing them.
Also Thursday, TEPCO said fuel inside the Nos. 1 to 3 reactors at the plant is expected to continue producing total heat equivalent to roughly 3,000 kilowatts of thermal output even six months after the quake.
The operator estimates that each of the three reactors produced between 1,000 and 2,000 kilowatts of heat on May 20, indicating the need to swiftly establish a stable cooling system to bring them into a stable condition called ''cold shutdown.''
Even if reactors are suspended, nuclear fuel inside them continues to emit heat as radioactive elements decay, and the rate at which the level of heat decreases becomes more gradual over time.
==Kyodo
2011-05-26 23:21:12
The utility, known as TEPCO, said it learned of the move after questioning the head of the Fukushima Daiichi nuclear power plant, who told company officials this week that he had gone ahead in continuing seawater injection into the No. 1 reactor despite the firm's decision to suspend the work.
TEPCO had earlier said it began injecting seawater to cool nuclear fuel inside the reactor on the evening of March 12, one day after the magnitude 9.0 earthquake and tsunami, but that it suspended the work 21 minutes later before resuming it another 55 minutes afterward.
A crisis management office consisting of government and TEPCO officials had said the initial injection was suspended after the prime minister's office conveyed its concern that seawater injection could cause fuel rods to resume fission, a phenomenon otherwise called ''recriticality.'' The work was resumed after Prime Minister Naoto Kan gave a directive for the seawater injection, according to the office.
TEPCO said the plant chief, Masao Yoshida, had thought it safer to continue injecting the seawater to prevent the crisis from worsening, adding that the latest finding came to light during its questioning of him between Tuesday and Wednesday. TEPCO conducted the questioning after the issue became a focus of attention in Diet deliberations, it said.
''I decided to report the facts because of a probe conducted by the International Atomic Energy Agency and because various international appraisals are forthcoming,'' Yoshida was quoted by a TEPCO official as telling the company.
While defending Yoshida's decision to continue injecting seawater as ''technically reasonable,'' TEPCO's Vice President Sakae Muto said at a news conference that his company is considering punishing Yoshida for not promptly reporting the facts.
Chief Cabinet Secretary Yukio Edano criticized TEPCO for the latest turn of events, telling a separate news conference, ''The public will harbor mistrust unless facts are reported accurately.''
Seawater injection was deemed necessary to cool fuel inside the reactor after the injection of fresh water stopped in the aftermath of the quake and tsunami, which knocked out key cooling systems at the plant.
Earlier Thursday, TEPCO said the level of highly radioactive water at a temporary water storage building had dropped by around 5 centimeters after the liquid was diverted from elsewhere at the plant.
The utility then found that the water appears to have seeped into a corridor that connects the building and another at the plant's same nuclear waste disposal facility, it said, adding the water was about 2 meters deep.
While the utility has not detected unusual levels of radioactive substances in nearby groundwater, it will increase the number of sampling spots for groundwater and beef up its surveillance, because the water leakage into the environment could affect the company's overall plan to remove contaminated water from reactor-related facilities to enable work inside them.
The operator stopped transferring the contaminated water from the No. 3 reactor's turbine building to the storage building at 9 a.m. Wednesday as the total amount of water came close to a planned limit.
It stopped transferring similar water to another building at the same facility from an underground tunnel near the plant's No. 2 reactor on Thursday for the same reason.
While the amount of diverted water from the two spots has already reached the planned limit of around 14,000 tons, TEPCO said Wednesday that an additional 5,000 tons of contaminated water could be transferred there.
At the power plant, water has been pumped into reactors to cool the fuel inside them since their cooling systems were disabled. The water is suspected of leaking into reactor-housing buildings and facilities nearby due to ruptures in reactor pressure vessels and the containment vessels encasing them.
Also Thursday, TEPCO said fuel inside the Nos. 1 to 3 reactors at the plant is expected to continue producing total heat equivalent to roughly 3,000 kilowatts of thermal output even six months after the quake.
The operator estimates that each of the three reactors produced between 1,000 and 2,000 kilowatts of heat on May 20, indicating the need to swiftly establish a stable cooling system to bring them into a stable condition called ''cold shutdown.''
Even if reactors are suspended, nuclear fuel inside them continues to emit heat as radioactive elements decay, and the rate at which the level of heat decreases becomes more gradual over time.
==Kyodo
2011-05-26 23:21:12
