Work Under Way to Prevent Explosion at Fukushima Reactor
Kyodo News (Japan)
TOKYO -- Tokyo Electric Power Co. on Wednesday started work to inject nitrogen into one of the reactors at the crippled Fukushima Daiichi nuclear power complex to reduce the potential risk of a hydrogen explosion, while it succeeded in stopping highly radioactive water leaking into the Pacific Ocean from the plant earlier in the day.
Nitrogen, an inert gas, will be injected into the No. 1 reactor's containment vessel from around 1 a.m. Thursday, a process that could take several days. Hidehiko Nishiyama, a spokesman for the government's Nuclear and Industrial Safety Agency,denied during a morning press conference that there is an ''immediate danger'' of explosion.
In addition to the task of maintaining the relative stability of all six reactors at the nuclear complex in Fukushima Prefecture, the utility firm known as TEPCO has also been engaged in efforts to stop highly radioactive water from leaking into the sea and cleaning up contaminated water within the plant.
According to estimates by TEPCO announced Wednesday, 25 percent of the nuclear fuel rods have been damaged at the No. 3 reactor. The company earlier said that 70 percent of the No. 1 reactor's fuel rods and 30 percent of the No. 2 reactor's fuel rods have been damaged.
Nishiyama said past hydrogen explosions have likely occurred due to hydrogen accumulation caused by the reaction of melted fuel rods' zirconium with steam from the coolant water. But now there is concern that hydrogen could accumulate in the No. 1 reactor under a different process involving radiation-induced decomposition of water into hydrogen and oxygen. more..