Post by Ex_Nuke_Troop on Feb 25, 2014 19:54:40 GMT
The Voice of Russia : Fukushima woes continue as cooling system fails at fourth nuclear reactor
The cooling system for a storage pool for spent fuel at the fourth unit of the Fukushima-1 nuclear plant has ceased functioning. Experts are trying to urgently switch the device to emergency stand-by power, the Tokyo Electric Power company (TEPCO) reports.
Apparently, the cooling system failed as a result of damage to the power cable supplying it with energy due to works near the unit. Currently, the temperature of the water in the pool is within the established norms, i.e. below + 20 degrees Celsius. The level above 65 degrees is considered dangerous.
The new accident led to interruption of works at the fourth unit aimed at extraction of fuel assemblies from its pool. In March 2011, this building was badly damaged by explosions of hydrogen; it may potentially collapse in case of a new powerful earthquake. That is why extraction of fuel assemblies from there is now considered the most urgent task. This operation, which some experts compare with removing cigarettes from a crumpled pack, should be completed by the end of 2014.
There are more than 1.5 thousand assemblies of the total mass of 400 tons in the pool of the fourth power unit. Among them, there are more than 1.3 thousand assemblies of spent fuel, which in case of damage or depressurization may emit large amounts of radioactive substances into the atmosphere. After the end of the works at the fourth power unit, by the end of 2015, it is planned to extract assemblies of spent fuel from the pools on the upper floors of the three other damaged units, where there are much smaller quantities of them.
The building of the fourth power unit is now covered with a protective sheath made of a special fabric and mounted on a steel frame. This construction is to prevent the spread of radiation in case of any incident during removing fuel assemblies. Earlier, the pool was cleared of large fragments of the walls and roof of the building that got there as a result of explosions in the spring of 2011. However, small fragments of concrete and armature, which may pose difficulties during the works, still remain in the pool.
The Fukushima-1 nuclear power plant was seriously damaged as a result of a14-meter tsunami in March 2011. Nuclear-fuel meltdown took place in three of its six reactors because of a fail of the cooling system, which was accompanied by significant emissions of radioactive substances.
Poor management at Japan Fukushima nuclear plant blamed for water leak
Japan's nuclear regulators said poor management was responsible for the worst leak of toxic water in six months at the crippled Fukushima nuclear plant, news reports said Tuesday.
The operator of the plant, Tokyo Electric Power Co, was criticized for insufficient crisis management after the leak of about 100 tons of water containing high levels of radioactive material from a storage tank at the Fukushima Daiichi Nuclear Power Station last week, Tokyo Shimbun reported.
The leak was attributed to a wrong valve setting, which led to the tank overflowing with contaminated water, and the lack of an alarm warning of a rise in water levels.
Tokyo Electric officials conceded that workers at a control room had failed to notice the problem soon enough.
"The failure to check the water level of the tanks that should have been receiving water was a problem from the viewpoint of preventing the situation from worsening," Nuclear Regulation Authority commissioner Toyoshi Fuketa said.
The leak was the largest since about 300 tons of toxic water escaped from another storage tank in August.
The plant suffered a triple meltdown after a tsunami swept through the complex in March 2011.
The operator is injecting water into the three reactors to keep them cool, and has been battling leaks from storage containers where the resulting radioactive water is being stored.
voiceofrussia.com/news/2014_02_25/Fukushima-woes-continue-as-cooling-system-fails-at-fourth-nuclear-reactor-7808/
The cooling system for a storage pool for spent fuel at the fourth unit of the Fukushima-1 nuclear plant has ceased functioning. Experts are trying to urgently switch the device to emergency stand-by power, the Tokyo Electric Power company (TEPCO) reports.
Apparently, the cooling system failed as a result of damage to the power cable supplying it with energy due to works near the unit. Currently, the temperature of the water in the pool is within the established norms, i.e. below + 20 degrees Celsius. The level above 65 degrees is considered dangerous.
The new accident led to interruption of works at the fourth unit aimed at extraction of fuel assemblies from its pool. In March 2011, this building was badly damaged by explosions of hydrogen; it may potentially collapse in case of a new powerful earthquake. That is why extraction of fuel assemblies from there is now considered the most urgent task. This operation, which some experts compare with removing cigarettes from a crumpled pack, should be completed by the end of 2014.
There are more than 1.5 thousand assemblies of the total mass of 400 tons in the pool of the fourth power unit. Among them, there are more than 1.3 thousand assemblies of spent fuel, which in case of damage or depressurization may emit large amounts of radioactive substances into the atmosphere. After the end of the works at the fourth power unit, by the end of 2015, it is planned to extract assemblies of spent fuel from the pools on the upper floors of the three other damaged units, where there are much smaller quantities of them.
The building of the fourth power unit is now covered with a protective sheath made of a special fabric and mounted on a steel frame. This construction is to prevent the spread of radiation in case of any incident during removing fuel assemblies. Earlier, the pool was cleared of large fragments of the walls and roof of the building that got there as a result of explosions in the spring of 2011. However, small fragments of concrete and armature, which may pose difficulties during the works, still remain in the pool.
The Fukushima-1 nuclear power plant was seriously damaged as a result of a14-meter tsunami in March 2011. Nuclear-fuel meltdown took place in three of its six reactors because of a fail of the cooling system, which was accompanied by significant emissions of radioactive substances.
Poor management at Japan Fukushima nuclear plant blamed for water leak
Japan's nuclear regulators said poor management was responsible for the worst leak of toxic water in six months at the crippled Fukushima nuclear plant, news reports said Tuesday.
The operator of the plant, Tokyo Electric Power Co, was criticized for insufficient crisis management after the leak of about 100 tons of water containing high levels of radioactive material from a storage tank at the Fukushima Daiichi Nuclear Power Station last week, Tokyo Shimbun reported.
The leak was attributed to a wrong valve setting, which led to the tank overflowing with contaminated water, and the lack of an alarm warning of a rise in water levels.
Tokyo Electric officials conceded that workers at a control room had failed to notice the problem soon enough.
"The failure to check the water level of the tanks that should have been receiving water was a problem from the viewpoint of preventing the situation from worsening," Nuclear Regulation Authority commissioner Toyoshi Fuketa said.
The leak was the largest since about 300 tons of toxic water escaped from another storage tank in August.
The plant suffered a triple meltdown after a tsunami swept through the complex in March 2011.
The operator is injecting water into the three reactors to keep them cool, and has been battling leaks from storage containers where the resulting radioactive water is being stored.
voiceofrussia.com/news/2014_02_25/Fukushima-woes-continue-as-cooling-system-fails-at-fourth-nuclear-reactor-7808/