Reactions to Shika 1 criticality

[Reuters, 15 March; Asahi, IHT, 17 March]Two Japanese nuclear utilities, Chubu and Tohoku, have admittedincidents involving fallen control rods similar to that which caused acriticality at Hokuriku's Shika 1 in 1999. In all three events, boilingwater reactors were shut down for inspections when control rods slippedfrom their proper positions. In the case of Shika 1, this initiated acriticality that lasted 15 minutes and should have been reported bylaw. Hokuriku's Toshihiko Takahashi described his company'sactions as a "cover up." In the other incidents, which occurred eightand 11 years earlier under different legislation, the fallen rods weretoo far apart for criticality to occur. Both the Japan Atomic EnergyCommission and the Ministry of Economy Trade and Industry condemnedpast secrecy of nuclear operations and called for increased sharing ofexperience, which they said could have prevented the Shika 1 incident.