Nuclear-Plant Analyses Ordered

Signaling that aging nuclear-power plants may face greater scrutiny, U.S. regulators have told utilities to more rigorously analyze metal fatigue at several sites, including two opposed by environmentalists.

The heightened scrutiny comes as a slew of older plants, dating to the late 1960s and early 1970s, seek operating-license renewals from the Nuclear Regulatory Commission. The NRC has extended the licenses of four dozen nuclear-power reactors since 2000. It is considering requests for nearly a dozen more, including Exelon Corp.'s Oyster Creek plant in New Jersey and Entergy Corp.'s Vermont Yankee plant, which have been targeted by environmentalists.

The NRC has received applications for 15 new reactors, with many more expected. The revival is driven by concerns about growing power needs and global-warming emissions from power sources such as coal.

Attention to new plants has spilled over to older plants. The Senate expressed interest in the license issue this week. Sen. Tom Carper (D., Del.), chairman of the Senate Subcommittee on Clean Air and Nuclear Safety, part of the Committee on Environment and Public Works, said he intends to hold a hearing next month on new-reactor licensing and will expand the scope to include extensions of existing licenses.

In the case of the Oyster Creek and Vermont Yankee plants, environmental groups have challenged metal-fatigue analyses; specifically, whether metal used in some pieces of equipment is strong enough to last another 20 years without jeopardizing safety. The commission's judicial arm, the Atomic Safety Licensing Board, has agreed to evaluate the matter.

In the interim, the commission issued a notice last week agreeing that the current "simplified" method of calculation may not be "conservative" enough.

"We concluded the analysis should have been more layered and detailed than it was," said Neil Sheehan, an NRC spokesman in the Northeast region.

The new scrutiny may not hinder license extensions. A spokeswoman for Exelon said the company believes "results will be similar" from the new methodology versus the old, because "we believe they're equally conservative."

John Dreyfuss, director of nuclear safety at the Vermont Yankee plant, said he doesn't think a change in metal-fatigue calculations will "drive any physical changes" at his plant because he expects it to pass either way. He said most parts and materials are engineered to rigorous standards and are highly durable.

It is unusual for interveners to mount a successful challenge, in part because the NRC has limited the scope of matters that may be raised in re-licensing proceedings. Interveners must identify deficiencies in an operator's plans to mitigate the effects of aging, but they aren't allowed to challenge things such as the proximity of the plant to a growing population, waste-disposal issues or some other matters.

Nearly half the U.S. fleet of 104 reactors faces license expirations from 2009 through 2015. No utility requesting a license extension has been refused to date, although the NRC sometimes attaches conditions to renewals.

One challenger to Oyster Creek said he regarded the NRC notice as a victory because it demonstrates the value of public intervention. "Our view is the NRC is missing safety issues that need to be addressed," said Richard Webster, an attorney for the Eastern Environmental Law Center in Newark, N.J., which is active in the challenge.

One challenge concerned metal used in equipment near the reactor pressure vessel -- the heart of the nuclear plant -- and is subject to forces that can accelerate aging. The commission has identified metal fatigue as fundamental risk in aging plants.

Although the NRC believes plants can operate safely far longer than 40 years, it has acknowledged that some components have been designed for a 40-year life and may require special monitoring, strengthening or replacement.

The NRC staff instructed utilities that have requested license extensions to perform additional analysis. Utilities with plants that already have received renewals are instructed to "evaluate their situation relative to any fatigue calculations."

The U.S. derives about 20% of its electricity from nuclear-power reactors, and the percentage has remained constant even though no significant number of reactors has been added in many years. The industry has wrung more power out of existing plants by running them better and running them harder. Mass retirements will commence after 2030.