The discovery of xenon in the Fukushima No. 1 nuclear plant's reactor 2 earlier this week was likely a result of "spontaneous fission," a nuclear expert said Friday, agreeing with an earlier conclusion by Tokyo Electric Power Co. that some of the melted fuel did not reach the condition of "criticality," or sustained chain reaction, of nuclear fission.
But Katsutada Aoki, an expert in nuclear engineering who headed the reactor physics division of the Atomic Energy Society of Japan, also criticized Tepco, saying the utility could have done a better job in analyzing the implications of the newly discovered xenon gases and avoided spreading needless fear that a nuclear chain reaction might have restarted.
"The discovery of xenon in the reactor is no reason to fear anything serious," Aoki told The Japan Times.