NRC says manufacturing flaws 'negligible,' plant shutdowns not necessary

Dive Brief:

The U.S. Nuclear Regulatory Commission has rejected a petition by Beyond Nuclear and other public interest groups to shut down or take other remedial action for 18 reactors at 14 nuclear plants.
The petition alleged that the reactors named in the request rely on potentially defective safety-related components and potentially falsified quality assurance documentation.
Instead of accepting the recommendations of the petitioners, the NRC said the defects appear to be "negligible" and do not warrant immediate action.

Dive Insight:

In its petition to the NRC, Beyond Nuclear cited the potential defects in nuclear reactor components manufactured by AREVA-Le Creusot Forge (ACF). The defects involve flaws in the steel manufacturing process that result in carbon macrosegregation, a condition marked by excess carbon that can make the metal brittle and subject to sudden fracture or tearing under high pressure.

The flaw showed up when AREVA notified French authorities of anomalies in the upper and lower heads of the reactor pressure vessel of unit 3 of the Flamanville nuclear plant in France. Both of those parts were manufactured by ACF.

The discovery prompted French regulators to request Electricite de France to close the reactor in order to test the materials in the reactor. Eventually 20 of the country's 58 reactors were taken offline.

The NRC examined the records of tests done on the French reactors, but the ruling from Brian E. Holian, acting director, of NRC's Office of Nuclear Reactor Regulation, concluded that "performing nondestructive examinations of the inservice components is not expected to provide information that would significantly affect the defense-in-depth, safety margins, or risk-level determinations that would be provided by continued monitoring and evaluation of new information."

Put another way, "the risk criterion to shut down a plant is not met," NRC says in its decision, published in the Aug. 10 Federal Register.

"We wanted the NRC to close the affected reactors in the U.S. to do material testing," Paul Gunter, director of Beyond Nuclear's reactor oversight project, told Utility Dive. That did not happen, but Beyond Nuclear's filing "created a benchmark" and puts the NRC on record with respect to the issue, he said.

There is no recourse to a director's ruling, Gunter said.

The list of U.S. reactors with ACF components includes the South Texas plant, the North Anna plant in Virginia, Dominion's Millstone plant in Connecticut, the V.C. Summer plant in South Carolina, and the Beaver Valley station in Pennsylvania.