A leading Senate Republican says the Nuclear Regulatory Commission's failure to compare Japanese and U.S. regulations for nuclear plants may weaken a safety review the agency is expected to make public today.

Senate Environment and Public Works Committee ranking member James Inhofe of Oklahoma told NRC Chairman Gregory Jaczko in a July 8 letter that the agency should compare the two countries' safety requirements to legitimize new regulations stemming from a months-long review of American plants.

"The absence of such a review would diminish the credibility of any new regulatory requirements since there would be no clear basis for assessing whether the recommended changes accurately and adequately address actual programs highlighted by the Fukushima accident," Inhofe wrote.

He added that he is concerned NRC's efforts on the issue are "inadequate."

NRC did not provide comment on Inhofe's letter by publication time.

The nuclear commission launched a two-tiered safety review after a magnitude-9 earthquake and tsunami struck Japan's Fukushima Daiichi nuclear complex on March 11, triggering explosions and radioactive leaks at the site. NRC initiated a short-term, 90-day review to determine whether immediate changes are needed and a long-term review has also begun.

The commission, which has repeatedly insisted American reactors are safe, sent its short-term findings to the White House yesterday and is expected to make the report public today (Greenwire, July 12).

NRC is reviewing whether plant operators can cool down reactor cores and spent fuel pools if there are large fires, explosions or other catastrophes similar to those that rocked the Fukushima plant.

Inhofe said NRC did not require its assembled task force to consider the differences between American and Japanese regulations until early last month, and even then the panel only considered the loss of power to nuclear reactors and gave the issue "very low emphasis."

An IAEA review found close ties between Japan's nuclear industry and its government regulator contributed to safety vulnerabilities at the Fukushima complex (ClimateWire, June 27).

The IAEA also found the Japanese government underestimated the magnitude of the tsunami that struck the Fukushima plant, Inhofe said. NRC should review whether its requirements for estimating such surges differ and whether there are differences in requirements for backup diesel generators at nuclear power plants, he said. The tsunami on Japan's east coast washed away generators at the site crucial for cooling the damaged reactors.

The commission should also review U.S. and Japanese expectations and training of plant workers and compare how they prepare for major disasters, he said.

"These are a few areas, and there are surely others, where comparison and analysis need not wait until there is complete understanding of the technical details of the full event," Inhofe said, adding that any new regulatory activities should be considered with the degree of risk they reduce.

Click here to read Inhofe's letter.