Workers continue to remove toxic water, cool spent nuke fuel pools
Apr. 13, 2011
Workers at the crisis-hit Fukushima Daiichi nuclear plant continued Wednesday to remove highly radioactive water in the plant and cool a spent nuclear fuel pool, as part of efforts to put an end to the ongoing emergency, which is now acknowledged as one of the world's worst nuclear disasters.
A magnitude 5.8 quake that hit areas near the power station Wednesday morning did not obstruct recovery efforts or cause any abnormalities at the plant, the government's Nuclear and Industrial Safety Agency said.
The plant operator Tokyo Electric Power Co. kept pumping out highly polluted water from an underground tunnel-like trench to a nearby storage area inside the No. 2 reactor's building.
The work began Tuesday evening and an estimated 200 tons of tainted water was moved to a ''condenser,'' where in normal operations steam from the reactor is converted into water, by 7:30 a.m. The utility known as TEPCO aims to transfer a total of 700 tons of polluted water by Thursday.
Eventually, the operator plans to remove a total of some 60,000 tons of contaminated water, found in the basements of the Nos. 1 to 3 reactor turbine buildings as well as the trenches connected to them, and to store it in nearby tanks and other areas.
Hidehiko Nishiyama, a spokesman for the government's nuclear regulatory body, said that as a result of the operation, the levels of highly radioactive water that had been filling up the trench and the basement of the No. 2 reactor's turbine building was lowered by 4 to 5 centimeters by 7 a.m. Wednesday.
The toxic water is believed to originate from the No. 2 reactor's core, where fuel rods have partially melted. The water, which has also affected other parts of the plant, is hampering efforts to restore the reactors' key cooling functions, lost in the March 11 earthquake and tsunami.
Nishiyama also said TEPCO sprayed some 195 tons of fresh water into a spent nuclear fuel pool at the No. 4 reactor's building through the night, after finding from a sample taken Tuesday from the facility that the temperature of the water was 90 C, much higher than the usual 20-30 C.
TEPCO has been unable to monitor the temperature of the pool water regularly as measuring equipment is not working. The No. 4 reactor, halted for a regular inspection before the quake, had all of its fuel rods stored in the pool for the maintenance work.
The injection of coolant water in the pool is needed to prevent damage to spent fuel rods from overheating. The water level in the facility has also been lowered following recent strong aftershocks that jolted the plant, TEPCO said.
Nishiyama said TEPCO also found that the radiation level in the air some 6 meters above the pool reached 84 millisieverts per hour before the water-spraying operation. The 400-milliliter water sample will be examined at the adjacent Fukushima Daini plant Wednesday to check to what extent the spent nuclear fuel stored there is damaged.
The spokesman also said the utility aims to finish installing seven steel sheets near a seawater intake for the No. 2 reactor later in the day and set up ''silt fence'' curtain barriers near intakes for the Nos. 3-4 reactors at the six-reactor plant to block the spread of radioactive substances in polluted water.
He added that a seawater sample taken Monday 15 kilometers away from the city of Minamisoma, Fukushima Prefecture, near the plant showed a radioactive iodine-131 concentration of about 23 times the maximum level permitted under law, but that it does not pose any health risks.
Massive amounts of water have been poured into the reactors and their spent nuclear fuel pools as a stopgap measure to cool them down. But pools of contaminated water have been detected in various parts of the nuclear complex on the Pacific coast, with some water leaking into the sea, as an apparent side effect of the emergency measure.
TEPCO successfully stopped the leak of highly radioactive water from a cracked pit on April 6.
(Distributed by Kyodo News on April 13, 2011)
A magnitude 5.8 quake that hit areas near the power station Wednesday morning did not obstruct recovery efforts or cause any abnormalities at the plant, the government's Nuclear and Industrial Safety Agency said.
The plant operator Tokyo Electric Power Co. kept pumping out highly polluted water from an underground tunnel-like trench to a nearby storage area inside the No. 2 reactor's building.
The work began Tuesday evening and an estimated 200 tons of tainted water was moved to a ''condenser,'' where in normal operations steam from the reactor is converted into water, by 7:30 a.m. The utility known as TEPCO aims to transfer a total of 700 tons of polluted water by Thursday.
Eventually, the operator plans to remove a total of some 60,000 tons of contaminated water, found in the basements of the Nos. 1 to 3 reactor turbine buildings as well as the trenches connected to them, and to store it in nearby tanks and other areas.
Hidehiko Nishiyama, a spokesman for the government's nuclear regulatory body, said that as a result of the operation, the levels of highly radioactive water that had been filling up the trench and the basement of the No. 2 reactor's turbine building was lowered by 4 to 5 centimeters by 7 a.m. Wednesday.
The toxic water is believed to originate from the No. 2 reactor's core, where fuel rods have partially melted. The water, which has also affected other parts of the plant, is hampering efforts to restore the reactors' key cooling functions, lost in the March 11 earthquake and tsunami.
Nishiyama also said TEPCO sprayed some 195 tons of fresh water into a spent nuclear fuel pool at the No. 4 reactor's building through the night, after finding from a sample taken Tuesday from the facility that the temperature of the water was 90 C, much higher than the usual 20-30 C.
TEPCO has been unable to monitor the temperature of the pool water regularly as measuring equipment is not working. The No. 4 reactor, halted for a regular inspection before the quake, had all of its fuel rods stored in the pool for the maintenance work.
The injection of coolant water in the pool is needed to prevent damage to spent fuel rods from overheating. The water level in the facility has also been lowered following recent strong aftershocks that jolted the plant, TEPCO said.
Nishiyama said TEPCO also found that the radiation level in the air some 6 meters above the pool reached 84 millisieverts per hour before the water-spraying operation. The 400-milliliter water sample will be examined at the adjacent Fukushima Daini plant Wednesday to check to what extent the spent nuclear fuel stored there is damaged.
The spokesman also said the utility aims to finish installing seven steel sheets near a seawater intake for the No. 2 reactor later in the day and set up ''silt fence'' curtain barriers near intakes for the Nos. 3-4 reactors at the six-reactor plant to block the spread of radioactive substances in polluted water.
He added that a seawater sample taken Monday 15 kilometers away from the city of Minamisoma, Fukushima Prefecture, near the plant showed a radioactive iodine-131 concentration of about 23 times the maximum level permitted under law, but that it does not pose any health risks.
Massive amounts of water have been poured into the reactors and their spent nuclear fuel pools as a stopgap measure to cool them down. But pools of contaminated water have been detected in various parts of the nuclear complex on the Pacific coast, with some water leaking into the sea, as an apparent side effect of the emergency measure.
TEPCO successfully stopped the leak of highly radioactive water from a cracked pit on April 6.
(Distributed by Kyodo News on April 13, 2011)
