A Short Message from Japan

From: KOMURA Hiroo

A few days ago a reactor in Japan was forced to reduce its output manually from the rated power 820MW to 440MW. The reactor is a BWR, Shimane no.2. The event was initiated by the automatic shutdown of a cleaning unit for sea water coolant (in the secondary cooling system), which was caused by the increase of load to the unit by huge amount of jellyfish (!!!) surging to the seashore. The cleaning unit is located in the pool for sea waterstorage. It means the jellyfish passed through a water inlet and came close to a turbine building. It was not crude oil balls from a tanker this time that sneaked into the nuclear power station. The outage continued for nearly 90 min. Sure, no effect to the environment, as Chugoku Electric Company. A NPS, however, is not a facility produced with high technology but can be threatened even by a jellyfish. Laugh !

Hiroo KOMURA h-komura@ipch.shizuoka.ac.jp
Department of Engineering
3-5-1 Johoku, Hamamatsu, Japan
TEL & FAX 81-53-478-1096