nuclear-news

Nuclear proponents say that extending plants’ lifetimes is more economical — and a better way to hold down carbon dioxide emissions — than building new plants, although it will require extensive monitoring of steel, concrete, cable insulation and other components. But the idea is striking even to some members of the nuclear establishment.

At a meeting of the Nuclear Regulatory Commission in May, George Apostolakis, a risk expert who was then one of the five commissioners, pointed out that if operation were allowed until age 80, some reactors would be using designs substantially older than that.“I don’t know how we would explain to the public that these designs, 90-year-old designs, 100-year-old designs, are still safe to operate,” he said. “Don’t we need more convincing arguments than just ‘We’re managing aging effects’?”

“I mean, will you buy a car that was designed in ’64?” he asked…….

The leading candidates are Exelon’s two operating reactors at the Peach Bottom plant in Pennsylvania, 50 miles southeast of Harrisburg; Dominion’s twin Surry reactors, near Jamestown, Va.; and Duke’s threeOconee reactors, near Seneca, S.C., all dating from the early 1970s……..

As construction of new reactors tailed off to nearly nothing in the late 1980s, the Nuclear Regulatory Commission established a procedure in 1991 for 20-year license extensions, and it has now granted more than 70. Thus far it has not rejected any applications, although many are still under review……

The 1991 procedure allows for plants to receive additional 20-year extensions, but the commission is currently engaged in a major effort to determine the criteria it should set for years 61 to 80. It expects utilities to start seeking a second round of 20-year extensions by about 2018…….

Exposed to decades of radiation, some metal parts grow brittle and more likely to crack under stress. One potential source of stress is the emergency core cooling system; if the system sensed a leak in the piping, it could start up and dump huge volumes of cold water into a reactor, keeping it at operating pressure but at a far lower temperature. Engineers say that could lead to a condition called “pressurized thermal shock,” in which a reactor vessel would crack open……..

Jim Riccio, a nuclear policy analyst at Greenpeace, said: “This isn’t about running reactors until they are 80. It’s amortizing the large capital additions that the industry can’t afford right now.” The reactors, he noted, have been required to buy new hardware after the Fukushima Daiichi accident in 2011.

“The track record of this industry is a meltdown once a decade,” he said. “We have a concern that running reactors well beyond their economic lifetime and well into embrittlement is not sound.”……

To win a license extension, the plants do not have to show that they will be safe for 80 years, only that they have monitoring programs in place to promptly detect problems as they emerge……

David Lochbaum, a nuclear engineer at the Union of Concerned Scientists, told the commission that nothing was inherently unsafe about running a reactor until it was 80, but that even now, when almost all the plants running are decades old, evidence of design errors continues to surface, sometimes causing plants to shut down.

“The bottom line is that compliance with current licensing basis requirements has never been shown to be valid at any nuclear plant in the country, not any plant at any time,” he said.

http://www.nytimes.com/2014/10/20/business/power-plants-seek-to-extend-life-of-nuclear-reactors.html?_r=0