TOKYO — Engineers who investigated Japan’s nuclear crisis said Monday that government oversight of the crippled plant’s operator is still too lax, as public concern has grown over recent safety problems.
A power failure last month caused by a rat that short-circuited a switchboard left the Fukushima Daiichi nuclear plant’s fuel storage pools without cooling water for more than a day. Last Friday another cooling failure occurred, and hours later the operator reported a large leak of radioactive water from underground tanks.
The plant’s operator, Tokyo Electric Power Co., disclosed Saturday that up to 120 tons of highly contaminated water escaped from a temporary underground tank and a smaller amount from another tank. TEPCO said it believes the water has not flowed into the ocean.
Regulators asked TEPCO on Monday to determine the cause and contain the problem quickly.
But the investigators told parliament on Monday that the recently formed Nuclear Regulation Authority is merely rubber-stamping TEPCO’s work at the plant, which is still using makeshift equipment put together after the March 2011 disaster, caused by a massive earthquake and tsunami in northeastern Japan.
The authority began in September as a more independent, tougher regulator.
Nine of the investigators testified Monday at a parliamentary nuclear committee for the first time since releasing their findings in July. The report called the disaster ‘‘man-made’’ and blamed regulator-operator collusion and botched crisis management.