Fukushima seawater may affect reactor cooling: France

Paris (AFP) March 23, 2011 Emergency use of seawater at Fukushima could harm longer-term efforts to cool the plant's crippled reactors, France's nuclear watchdog said Wednesday. The agency said it was "concerned" that salt from seawater used extensively to cool the reactor cores could be corrosive or build up in crystalline layers inside heat exchangers and valves, hampering their efficiency.
This equipment will be needed when pumping power is restored at the plant and coolant is recirculated as normal, the Institute for Radiological Protection and Nuclear Safety (IRSN) said.
"The impacts from the presence of salt in the water could affect the cooling of the fuel within a very short time," the IRSN said. "The general recommendation is to rebuild stocks of freshwater on site."
Engineers resorted to the desperate step of injecting seawater into three reactors to cover fuel rods that dangerously overheat if exposed to air.
Pumping capacity at the plant was knocked by the March 11 earthquake and tsunami that struck northeastern Honshu.