...which has a say in whether the plant continues to operate, last year voted against it continuing operation. Entergy spokesman Larry Smith says the firm is seeking a “constructive resolution” with the legislature.

“The plant is key to the reliability of the electric grid in New England,” Smith says. It supplies 467,000 MWh of the 627,000 MWh produced in the state, says the U.S. Energy Information Administration. In New York, the New York Independent System Operator, which manages the state electrical grid, reported in its 2010 comprehensive reliability plan that “power flows on the system into southeast New York would cause increased reactive power losses if the Indian Point plant licenses are not renewed.”

Of growing concern is the storage of spent fuel rods at these and other plants around the U.S. UCS says spent fuel pools are vulnerable to natural or man-made disasters. If the system that circulates and cools the water over the rods stops working, the water in the pool could evaporate, which could lead the rods to heat up and become damaged or even melt down and release radiation into the atmosphere, says the group. UCS’s Lyman says the U.S. has 35 boiling-water reactors that mimic Fukushima’s configuration.

Smith says that just as in Fukushima, Vermont Yankee stores its spent fuel rods in pools that are covered by a sheet metal building, but that the plant is slowly converting to dry cask storage until the U.S. government determines what to do with the waste in the long term.

Fred Upton (R-Mich.), chairman of the House Energy and Commerce Committee, told Energy Secretary Steven Chu and Jaczko that he was concerned about the administration’s decision to shut down Yucca Mountain. “Blocking Yucca Mountain is penny wise and pound foolish, especially considering the $13.5 billion already spent and the need for an ultimate repository for nuclear waste.” He said his committee “will look long and hard at Yucca Mountain, the nuclear fuel cycle and spent fuel policies.”

Chu told committee members that the administration is awaiting recommendations from the Blue Ribbon Commission on America’s Nuclear Future when it releases a draft report in June.

Peter Bradford, an NRC commissioner between 1977 and 1982, says that the nuclear industry was already having problems before the Japanese disaster. “It’s hard to imagine that legislators will be as willing to assign the risk of new nuclear construction to taxpayers or to customers going forward as they might have been before these past few weeks,” he says.

Dmitri Nikas, an analyst with Standard & Poor’s utilities and infrastructure division, told Platt’s on March 20 that it is “too early to tell” the disaster’s impact on the financing of new nuclear plants, but that facilities that were under consideration, but not under construction, “may have a few more challenges to overcome.” Platt’s and S&P, like ENR, are units of The McGraw-Hill Cos.

Benjamin Salisbury, an analyst at FBR Capital markets also told Platt’s that there would certainly be delays, extensions and reconsiderations of construction costs and licensing of new plants following Fukushima. Both analysts said that the problems would be more severe for plants proposed by merchant developers, those that planned to sell their power into the open market, rather than those that are a regulated monopoly in a state such as Georgia, where Southern Co. has said it plans to move forward with two new units in Waynesboro.

On March 21, merchant developer Nuclear Innovation North America (NINA), a joint venture of NRG Energy and Toshiba Corp., announced that it was reducing the scope of development at its South Texas Project expansion to allow time for the NRC and other nuclear stakeholders to assess the lessons that can be learned from the events in Japan.

“Our best course of action in this immediate period of uncertainty is to minimize project spend, continue with those activities we can control and wait until there is more information upon which we can base our long-term decisions,” said David Crane, CEO of NRG.

Hardy, who examined the Toyko Electric Power Co.’s Kashiwazaki-Kariwa nuclear plant in Japan after a 2007 earthquake, says that plants in the U.S., and even in Japan, are sufficiently built to withstand an earthquake. He says ground acceleration at Kashiwazaki was more than 1g. Preliminary measurements indicate that acceleration at Fukushima was about half that, in the .5g to .6g range. Following the 2007 quake, nuclear-related systems at Kashiwazaki were working and undamaged, he says.

That indicates to Hardy that the quake did not damage the nuclear plants, but that they were crippled by the tsunami. On March 21, Japan's NHK broadcasting network reported that Tokyo Electric Power Co. confirmed that the earthquake and tsunami were beyond the Fukushima Daiichi plant's design standards.

TEPCO believes the tsunami that inundated the Fukushima Daiichi site was 14 meters high, the network said. The design basis tsunami for the site was 5.7 meters, and the reactors and backup power sources were located 10 to 13 meters above sea level.

Forensics and modeling

Hardy says that the forensic analysis of what happened at Fukushima will be challenging because the three dynamic events —the earthquake, tsunami and explosions —will all have created different impacts on the nuclear plant. He says that after all information is gathered, he and others will use computer models to determine whether shaking caused electrical, mechanical or piping failures. That analysis will take years, he says.

But Hardy maintains that U.S. plants are built to higher standards than Japanese plants. The U.S. adds an additional safety margin to its designs by taking a probabilistic approach; the Japanese take a more deterministic approach and don’t include an extra margin of safety that is in U.S. designs, he contends.

But others are concerned about the aging reactors. Mohammed Ettouney, a principal at Weidlinger Associates, says all structures degrade, and the nation’s 40-year-old nuclear plants should be closely evaluated. He says while plant demands have increased, their capacities have degraded: “It’s the law of nature.”