A power outage left four fuel storage pools at Japan’s tsunami-damaged Fukushima Dai-ichi nuclear power plant without fresh cooling water for nearly 20 hours.
The issues raises concerns about a facility that still runs on makeshift equipment, but Tokyo Electric Power Co. (TEPCO) said pool temperatures at the plant were within safe levels and that pools would remain safe for at least four days without fresh cooling water. The utility said the reactors were unaffected and there were no other abnormalities.
The cooling system ended up restored at one of the four pools by mid-afternoon Tuesday, and the systems for the three other pools should resume by Wednesday as workers complete repairs and try to determine the cause the problem, TEPCO officials said.
Workers fixed the last of the three switchboards they suspect as a possible cause of the problem and the utility was preparing a backup system in case the repairs did not the issue, TEPCO spokesman Masayuki Ono said.
Japan’s March 11, 2011, earthquake and tsunami destroyed the plant’s power and cooling systems, causing three reactor cores to melt and fuel storage pools to overheat.
Ono admitted that the plant was vulnerable.
“Fukushima Dai-ichi still runs on makeshift equipment and we are trying to switch to something more permanent and dependable, which is more desirable,” he said. “Considering the equipment situation, we may be pushing a little too hard.”
Ono said the utility did not immediately switch to a backup cooling system because doing so without fixing the cause could lead to a repeat of the problem.
Regulators have raised concerns about the makeshift equipment and urged the plant to switch to a more permanent arrangement.
TEPCO still has to remove radioactive fuel from the reactors before fully decommissioning the plant, which could take 40 years.