23 Mars 2013
March 21, 2013
On the evening of March 18, a major power cut hit Tokyo Electric Power Co. (TEPCO)'s Fukushima No. 1 Nuclear Power Plant, disabling nine facilities at the plant including equipment to cool pools of spent nuclear fuel. It took over 19 hours for all equipment to be restored to order.
The power outage is believed to have been caused by a short circuit that occurred when a rat found its way into a temporary switchboard. After more than two years following the March 11, 2011 earthquake and tsunami that crippled the plant, why has TEPCO not managed to create a system that could defend itself against such an incident? Apart from local residents, many other members of the general public were no doubt left wondering whether the power company should be left to handle the nuclear crisis.
TEPCO labeled the power cut an "event," not an "accident," but the international community has a strong interest in the state of pools containing spent nuclear fuel, and the issue is of concern to residents. We call on TEPCO to quickly step up measures to prevent a recurrence.
The pools whose cooling systems were knocked out contain some 9,000 rods of spent nuclear fuel. If the pools aren't cooled the water temperature rises. Left unchecked, this will eventually cause the water to evaporate, and, in a worst-case scenario, could lead to a meltdown.
The switchboard that short circuited had been brought in immediately after the outbreak of the nuclear crisis in 2011 and placed on the bed of a truck. Since it takes some time for the temperature of the water in spent fuel pools to rise, TEPCO had not prepared a backup system like those in place to inject water into reactor cores. Officials at the utility had planned to adopt measures this month.
The Fukushima nuclear crisis showed us the importance of having multiple layers of protection and diverse protection methods in place at nuclear plants. Officials were lax in not preparing a backup system. Many pipes, tanks and other equipment at the Fukushima No. 1 plant are merely temporary, as workers are still busy responding to the disaster. Officials must move to quickly upgrade this peripheral equipment.
In the latest incident, the temperature of the pools for spent fuel were kept below the prescribed level, but if officials are lax in maintaining some equipment on the grounds that it is merely peripheral, it could result in a major, unforeseen accident.
The Nuclear Regulation Authority (NRA) has set up a panel to screen the Fukushima decommissioning plans. The panel and TEPCO should use the power outage as a lesson to re-examine whether there are any holes in safety measures at the plant.
TEPCO is due to set up an "international advisory team" in the near future to gather technical advice and other recommendations from overseas experts on the decommissioning process. There is great significance in having third parties with experience and technical expertise check the decommissioning plans, and in publicly disclosing problems in an easily understandable format.
At the same time, TEPCO's delay in publicly announcing the power cut cannot be overlooked. The utility alerted the NRA soon after the outage, but waited an hour before reporting the problem to the Fukushima Prefectural Government and over three hours before telling the media. Does TEPCO answer to the public, or only to regulatory authorities? The latest incidents have probably only served to fuel residents' distrust in TEPCO. We want to see a response that places priority on the disclosure of information.