WASHINGTON — The Nuclear Regulatory Commission should take immediate steps to improve the safety of pools containing radioactive waste stored at U.S. nuclear plants, an internal report released Wednesday said.
The report by NRC staff elevates the importance of spent-fuel pools, saying current regulations do not require instruments measuring water levels to be operable in case of accident. Water levels at spent-fuel pools were a key issue after a March 11 earthquake and tsunami that crippled a nuclear plant in Japan.
NRC Chairman Gregory Jaczko initially said a spent-fuel pool at the plant was dry, a claim that Japanese officials sharply disputed. NRC officials later acknowledged Jaczko spoke in error.
Jaczko's claim, which he never fully explained, sparked international headlines and raised the possibility of widespread nuclear fallout at the Japanese plant. Loss of cooling water in the reactor core could have exposed highly radioactive spent fuel rods, increasing the threat of a complete fuel meltdown and a catastrophic release of radiation.
Japanese officials denied the pool was dry and reported that the plant's condition was stable.
In June, three months after the tsunami, U.S. officials said newly obtained video showed that the spent fuel pool at Unit 4 at the Fukushima Dai-ichi complex probably did not go dry, as Jaczko had insisted in March.
U.S. officials have never fully explained why Jaczko made the claim, but said it was based on information from NRC staff and other experts who went to Japan after the disaster.
In its report Wednesday, NRC staff said that requiring plants to have more reliable instruments to measure water levels at spent fuel pools would give operators and regulators more information about radioactive waste during an extended power loss that could disable cooling equipment. Pools containing radioactive waste need to be kept cool to avoid meltdowns.
The recommendation on spent-fuel pools is one of eight steps agency staff says the NRC should take "without delay" as it responds to the Japan crisis.
The report also recommended immediate reviews of seismic and flooding risks at the nation's 104 nuclear reactors. Those risks have come under greater scrutiny in the wake of the Japan crisis and the East Coast earthquake in August, which caused the ground to shake much more than a Virginia nuclear plant near the quake's epicenter was designed to withstand.
The report also said plant operators should be required to improve their response to prolonged power blackouts or events that damage more than one reactor at the same time, as happened in Japan.
Follow Matthew Daly's energy coverage at http://twitter.com/MatthewDalyWDC