Heat exchangers will be installed to cool spent fuel rod storage pools at the Fukushima No. 1 nuclear power plant, according to a report submitted May 21 by the plant operator, Tokyo Electric Power Co., to the Nuclear and Industrial Safety Agency.
Heat exchangers will be installed to cool spent fuel rod storage pools at the Fukushima No. 1 nuclear power plant, according to a report submitted May 21 by the plant operator, Tokyo Electric Power Co., to the Nuclear and Industrial Safety Agency.
To establish a stable reactor cooling system, TEPCO plans to equip the No. 2 reactor with a heat exchanger by the end of this month, and will do the same for the No. 1 and No. 3 reactors in June, and No. 4 in July.
The report says a heat exchanger installed outside the reactor building will cool primary water--which has been heated due to intense heat from spent fuel rods--running through existing pipes. The heat exchanger will then re-inject the cooled water into the storage pool.
Secondary water, which is used to cool the primary water and has become hot during the cooling process, will be cooled by air-cooling equipment, also set up outside the reactor building.
Currently, the water temperature in the storage pool of the No. 2 reactor is between 70 and 80 degrees--well above its normal temperature of 30-35 degrees. TEPCO is now only adding an amount of water equivalent to the amount that evaporates amid high heat from spent fuel rods. With this newly installed heat exchanger, the company expects the water temperature to drop to 41 degrees in a month.
Equipment and pipes inside the No. 2 reactor building have not been damaged as much as those in the other reactor buildings at the plant. Thanks to the minimal damage, TEPCO was able to begin preparation work for the heat exchanger at the No. 2 reactor earlier than at the other reactors. Due to substantial damage to equipment and pipes at the other reactors, water-injection vehicles have been used to pump water into the No. 1 and No. 4 reactors.
TEPCO workers entered the No. 1 reactor building on May 20 to measure gamma radiation levels using a special radiation camera as a precautionary measure before attempting restoration of the reactor cooling system. The results indicated high levels of radiation in a loading entrance on the second floor for large machinery. TEPCO will take precautionary measures against these radiation sources.
With the No. 4 reactor requiring work for earthquake resistance and holding new fuel rods in the storage pool, it is expected to take more time to complete preparation work at the reactor for setting up a heat exchanger.