UPDATE 1-Japan's Chubu to shut nuclear unit for inspection

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TOKYO, Aug 8 (Reuters) - Chubu Electric Power Co (9502.T), Japan's third-biggest utility, said on Friday it plans to stop power output from its 1,137-megawatt Hamaoka No. 4 nuclear generator as early as Sunday for an unplanned inspection.

The unit is expected to be shut for about three to four days for inspection of a water regulating valve that is suspected of malfunctioning, a company spokesman said.

The utility expects no problems meeting electricity demand next week, because it forecasts it will have 8 percent or more surplus electricity generation capacity compared with expected peak demand, he said.

The shutdown coincides with Japan's "Obon" holidays, when power demand is typically lower as many Japanese return to their hometowns on vacation.

Chubu Electric supplies the region around the major city of Nagoya in central Japan. (Reporting by Osamu Tsukimori; Editing by Chris Gallagher)