The Nuclear Regulatory Commission has wrapped up its safety evaluation for the license renewal for Energy Northwest's nuclear power plant near Richland.
"(It) concluded that there are no open items that would preclude license renewal for an additional 20 years of operation," according to an NRC announcement.
The evaluation shows that Energy Northwest has identified actions that have been or will be taken to manage the effects of aging of the Columbia Generating Station, according to the NRC.
However, an independent panel of experts that advises the NRC on reactor safety still must review the 886-page NRC report on safety that was issued this week. The Advisory Committee on Reactor Safeguards will meet in April and then issue a letter discussing the results of its review.
A final environmental study also must be issued, after a draft study released in August found no significant concerns. It is expected in April.
Then a decision on whether to extend the Columbia Generating Station's 40-year operating license for 20 years through 2043 will be made by NRC's director of nuclear reactor regulations. A decision is expected this summer.
Energy Northwest has been working toward license renewal for at least five years and spending about $20 million to date, said Don Gregoire, manager of regulatory affairs.
It began pulling together safety information 21/2 years before it filed its application.
A key focus of the safety review is identifying potential concerns and potential causes of aging and how that would be managed during an additional 20 years.
Metals may become more brittle and susceptible to fractures because of continual irradiation by neutrons. The wide temperature fluctuations in components associated with the production of steam also can make metals more brittle.
Energy Northwest provided the NRC with information on how it will continue to use or expand its aging management programs to operate the reactor for two more decades.
Then the NRC brought in its own experts for a technical review.