The government and Tokyo Electric Power Co., the operator of the tsunami-hit Fukushima No. 1 Nuclear Power Plant, should step up their monitoring of the plant’s reactors to check whether nuclear fission is occurring and provide good explanations of the situation in the reactors to the public.
Xenon was detected in the containment vessel of the plant’s No. 2 reactor, and the finding was confirmed by the semi-governmental Japan Atomic Energy Agency.
Small-scale criticality temporarily occurring in a reactor would not mean that the reactor is in a dangerous situation. Criticality can be sustained only if certain conditions, such as the right ratio of water and fuel inside the reactor, are met.
Still, we mustn’t let down our guard. The government and TEPCO need to find out why the fission has occurred and take appropriate responses. TEPCO has injected boric acid into the No. 2 reactor to prevent it from reaching criticality, but more may need to be done.
The gas inside the containment vessels of the Fukushima plant’s No. 1 and 3 reactors has not yet been analyzed. The government and TEPCO should carry out similar examinations of the inside of their containment vessels as soon as possible to check for nuclear fission occurring in them.
The conditions and locations of melted fuel in the plant’s No. 1 to 3 reactors as well as the details of the damage to the reactors remain unclear, and after this most recent finding, the government and TEPCO must step up their monitoring.
Continue reading at Editorial: Closer monitoring and more explanation of Fukushima reactors