Temperatures fall in spent fuel pools at Fukushima plant

In a promising development toward ending the Fukushima nuclear crisis, the temperature fell to 40.5 degrees in the spent fuel storage pool at the No. 1 reactor, Tokyo Electric Power Co. said Aug. 11. The temperature is expected to soon dip below 40 degrees if the cyclic cooling system, which started operating at 11:20 a.m. on Aug. 10, continues to run smoothly at the Fukushima No. 1 nuclear power plant, TEPCO, the plant's operator, said. At noon on Aug. 10, the temperature was 47 degrees. By 5 p.m. on Aug. 11, it had fallen to 40.5 degrees, TEPCO said. Cooling systems are now running for all storage pools at the No. 1 through No. 4 reactors. Separate systems to purify radioactive water and recycle it to cool down the No. 1 through No. 3 reactors are also in operation. The cooling equipment extracts water from the storage pools, cools it down and then pumps it back in. A hydrogen explosion blew off the roof of the No. 1 reactor building on March 12, the day after the Great East Japan Earthquake and tsunami triggered the nuclear crisis. Since then, pumps normally used to pour cement and existing pipes had been injecting water continually from the outside into the storage pool, located in an upper part of the building. The current cooling equipment is expected to keep the water temperature below 40 degrees. The cooling systems for the storage pools at the No. 2, No. 3 and No. 4 reactors went into operation on May 31, July 1 and July 31, respectively. The temperatures have remained stable between 30 and 40 degrees in the storage pools at the No. 2 and No. 3 reactors. But the temperature ranges between 40 and 45 degrees in the No. 4 reactor storage pool, which is generating more heat because it contains fuel rods removed from the reactor for regular inspections. Spent fuel rods continue to generate heat even after they are placed in a storage pool. Continued cooling is necessary to prevent them from melting and releasing radioactive substances. Achieving a stable, cyclic injection of water to cool down the storage pools at the four reactors was part of Step 2 of the road map of TEPCO and the government toward ending the nuclear crisis. Step 2 goals will be accomplished between October and January, according to the plan. If the cooling system holds, this goal will have been achieved more than two months ahead of schedule.