Risks remain at Japan's nuclear plants

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TOKYO, April 26 (UPI) -- Backup generators at many Japanese nuclear power plants lack capacity to keep reactor cores cool if another earthquake or tsunami were to strike, sources say.

Japanese nuclear regulators have urged the country's 11 nuclear plant operators to deploy extra truck-mounted generators on high ground where a tsunami won't swamp them, to provide power for cooling reactor systems via heavy-duty waterproof cables, NewScientist.com reported Tuesday.

However, sources in the nuclear utility companies have told Kyodo News the power the backups could provide would not be enough, NewScientist.com said.

At Hamaoka, a plant sitting on a quake-vulnerable subduction zone, Chubu Electric Power's nine newly deployed diesel generators lack sufficient power to cool the facility's five reactors, sources said.

Another plant at Tsuruga needs 3,500 kilowatts to safely cool its reactors, but the backups can only deliver 1,020 kilowatts, Kyodo reported, a situation that can't be remedied until next March.

The situation does not bode well for Japan. Nuclear power plants cannot be switched off since residual heat from low-level nuclear fission must continually be drawn away from the core, and a lack of backup power means the risk or further accidents remains a reality.