ID :
182258
Sun, 05/15/2011 - 17:49
Auther :
Shortlink :
https://oananews.org//node/182258
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Trouble delayed cold shutdown of Hamaoka nuke reactor
SHIZUOKA, Japan, May 15 Kyodo -
Chubu Electric Power Co. said Sunday that cooling system trouble delayed the 'cold shutdown' of the No. 5 reactor at its Hamaoka power plant in Shizuoka Prefecture for about two hours earlier in the day, while ruling out any external release of radioactive substances.
Seawater leaked into a steam condenser at the reactor, which cools and turns steam from the turbines into water, apparently due to damage to its piping, prompting the utility to switch to another system to cool and stabilize the reactor and complete the work shortly past noon, it said.
The No. 5 unit was the last active nuclear reactor at the plant located in the Pacific coastal city of Omaezaki to come to a stable condition with an internal temperature below 100 C, the benchmark for cold shutdown.
The utility serving central Japan halted operation of the plant -- its only nuclear facility located around 180 kilometers southwest of Tokyo -- on Saturday, following an unprecedented government request due to fears of another nuclear disaster in the event of a large earthquake in the area, which lies on a major active fault line.
The ongoing nuclear crisis at Tokyo Electric Power Co.'s Fukushima Daiichi power plant on the Pacific coast around 220 km northeast of Tokyo was triggered by the devastating March 11 quake and tsunami.
The Nagoya-based firm said it had found Saturday evening, after a measuring instrument indicated abnormalities around 4:30 p.m., that around 400 tons of seawater had flowed into the condenser of the No. 5 reactor.
The water also found its way into the reactor, making it necessary to desalinate it, the company said.
At the plant, the No. 4 reactor was halted Friday and came to a stable condition the following day while the No. 3 reactor was already suspended for regular checks. The Nos. 1 and 2 reactors at the plant have been shut down for decommissioning.
In a related development, Katsuya Okada, secretary general of the ruling Democratic Party of Japan, said Sunday nuclear power plants that remain closed or were shut down after the March 11 earthquake and tsunami should be restarted provided that they meet tougher safety standards.
''It is an irrefutable fact that Japan cannot secure the electricity it needs unless it utilizes existing nuclear plants and those under construction,'' he said, adding, ''The public is now taking a more critical view concerning the safety of atomic energy so revamping the existing safety standards should be a prerequisite (for continued use of nuclear facilities).''
Okada made the comments during a meeting with mayors of localities in Aomori Prefecture, where one nuclear power station is currently out of action and another is under construction.
Chubu Electric Power Co. said Sunday that cooling system trouble delayed the 'cold shutdown' of the No. 5 reactor at its Hamaoka power plant in Shizuoka Prefecture for about two hours earlier in the day, while ruling out any external release of radioactive substances.
Seawater leaked into a steam condenser at the reactor, which cools and turns steam from the turbines into water, apparently due to damage to its piping, prompting the utility to switch to another system to cool and stabilize the reactor and complete the work shortly past noon, it said.
The No. 5 unit was the last active nuclear reactor at the plant located in the Pacific coastal city of Omaezaki to come to a stable condition with an internal temperature below 100 C, the benchmark for cold shutdown.
The utility serving central Japan halted operation of the plant -- its only nuclear facility located around 180 kilometers southwest of Tokyo -- on Saturday, following an unprecedented government request due to fears of another nuclear disaster in the event of a large earthquake in the area, which lies on a major active fault line.
The ongoing nuclear crisis at Tokyo Electric Power Co.'s Fukushima Daiichi power plant on the Pacific coast around 220 km northeast of Tokyo was triggered by the devastating March 11 quake and tsunami.
The Nagoya-based firm said it had found Saturday evening, after a measuring instrument indicated abnormalities around 4:30 p.m., that around 400 tons of seawater had flowed into the condenser of the No. 5 reactor.
The water also found its way into the reactor, making it necessary to desalinate it, the company said.
At the plant, the No. 4 reactor was halted Friday and came to a stable condition the following day while the No. 3 reactor was already suspended for regular checks. The Nos. 1 and 2 reactors at the plant have been shut down for decommissioning.
In a related development, Katsuya Okada, secretary general of the ruling Democratic Party of Japan, said Sunday nuclear power plants that remain closed or were shut down after the March 11 earthquake and tsunami should be restarted provided that they meet tougher safety standards.
''It is an irrefutable fact that Japan cannot secure the electricity it needs unless it utilizes existing nuclear plants and those under construction,'' he said, adding, ''The public is now taking a more critical view concerning the safety of atomic energy so revamping the existing safety standards should be a prerequisite (for continued use of nuclear facilities).''
Okada made the comments during a meeting with mayors of localities in Aomori Prefecture, where one nuclear power station is currently out of action and another is under construction.
