There are no known generic issues that limit the lifetime of operating nuclear power plants, speakers told the PLIM/PLEX conference in Chicago in late September.

In the USA, every operating plant that has not yet had a life extension has, or is intending, to apply for one, according to Brian Holian, director of licence renewals for the US Nuclear Regulatory Commission.

And US utilities are increasingly interested in a second lifetime extension beyond 60 years to 80 years of life. “We do have a precedent for this–there are some hydro plants that were built over 100 years ago,” says Garry Young, Entergy’s head of business development. “The Vernon dam, next to Vermont Yankee nuclear power plant, is an example. The turbine and generators have been replaced, but the structure is still there, and continues to improve—in fact it generates more power today than it did when it was built,” Young says.

Speakers did differ about what might be the biggest limiting factors. Industry research organisation EPRI surveyed its 27 utility members about the issues and events that cause greatest concern about life extension. The first major issue was replacing reactor internals–primarily because of the level of interference with normal plant operations. The second major issue was general design obsolesence: “if you don’t keep on top of equipment lifecycle, and modify the technology, it becomes run down. This may have a significant cost, but we consider that it is worth it,” said EPRI technical executive John Gaertner. He said that the shutdowns of all 13 nuclear power plants in the last two decades might be attributable to general obsolesence. Events of greatest concern included terrorist attacks, loss of public or board confidence, and a radiological event.

Consultant Fred Polaski, formerly with utility Exelon, said that the continued availability of cooling water could prove to be a big problem. Audience member Julie Keys of the NEI added that regulatory stability was also a key factor in the continuing operation of NPPs. Garry Young of Entergy said that analogue control systems also posed a problem. Plants with analogue systems whose suppliers had gone out of business had been forced to reverse-engineer the system to fabricate replacement parts.

EPRI has begun a research and development strategy to examine life-beyond-60 issues that aims to yield research results beginning in 2014, Gaertner said. In addition, a joint EPRI-NEI workshop on life beyond 60 is scheduled for February 2011.

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