One of Japan's 2 online reactors may operate longer TOKYO (Reuters) - The last reactor in Japan scheduled to be shut down for maintenance following the Fukushima nuclear crisis could continue to operate slightly longer than planned, Hokkaido Electric Power Co said on Monday. Currently only two of Japan's 54 reactors are in operation as public safety fears over atomic energy and new government safety standards have prevented restarts. Hokkaido Electric said it may delay the shutdown of the 912-megawatt No.3 unit at its sole Tomari nuclear plant to early May from late April to increase power supply. The only other reactor in operation -- the 1,356-MW No.6 unit at Tokyo Electric Power Co's Kashiwazaki-Kariwa plant -- is scheduled to undergo maintenance from March 26. Reporting by Osamu Tsukimori; Editing by Edwina Gibbs