Restoration of cooling water circulation in Unit 4 high-level radioactive waste storage pool more challenging than Unit 2 at Fukushima Daiichi

A photo, taken through the camera's protective cover, shows workers in the turbine building of unit 2 (Image: Tepco)World Nuclear News reports that, despite very high humidity levels of 99.9% (like a radioactive sauna -- see photo at left), the May 31st re-establishment of cooling water circulation at Fukushima Daiichi's Unit 2 reactor building had succeeded by June 10th in reducing the temperature in the high-level radioactive waste storage pool 31 degrees Celsius (88 degrees Fahrenheit), near Tokyo Electric Power Company's goal of 25 degrees Celsius (77 degrees Fahrenheit). However, due to extensive damage at the Unit 4 high-level radioactive waste storage pool, it appears that such a fix won't be so easy. Unit 4's pool water is now 80 degrees Celsius (176 degrees Fahrenheit), dangerously close to boil. If the Unit 4 pool water boils away, exposing irradiated nuclear fuel to air, it could overheat, ignite, and release catastrophic amounts of hazardous radioactivity onto the winds and waves.