N.H. Nuke Plant's ASR Issues Remain Cause of Concern

SEABROOK — Members of the Advisory Committee on Reactor Safeguards’ License Renewal Subcommittee referred to Seabrook’s renewal application as a work in progress after a four-hour meeting Tuesday.

Both NextEra Engery, the owner and operator of the Seabrook Nuclear Power Plant, and staff members with the Nuclear Regulatory Commission presented information about safety concerns and how they are being addressed.

In its presentation, NextEra said the micro-cracks due to alkali-silica reaction (ASR) on concrete structures at Seabrook Station is understood and manageable.

But NRC staff members said they do not feel the plant has done enough to address ASR issues in the containment area, or in the 19 other structures at Seabrook affected by ASR.

ASR is a chemical reaction in concrete that occurs over time in the presence of water and humidity, and can cause micro-cracks that change the physical and structural properties of concrete.

It was first found at Seabrook last May. It is the first time ASR has been identified at a power plant.

NRC staff members say that NextEra has not yet demonstrated that it can adequately manage aging of the Seabrook concrete structures due to ASR for the period of extended operations.

Seabrook’s current license expires in 2030 and it is seeking a 20-year extension.

The committee reviewed a 770-page safety evaluation report, in addition to other status reports and references in preparation for the meeting.

NRC staff said they had differences with NextEra on the extent of, and how to manage, the ASR problem.

NextEra submitted an updated aging management plan to the NRC on May 16, which is still under review.

A representative from NextEra said they believe the ASR will continue. So far, the tests they have done were only six months apart and NextEra representatives said they were not prepared to say what condition the concrete would be in 60 years from now.

Abdul Sheikh, a senior engineer for the NRC, said NextEra’s argument is that the cracks are small.

“The applicant has to do more work in this area. It cannot dismiss that these cracks are insignificant because it could have a long-term impact on the containment integrity,” Sheikh said.

He said NRC staff do not have enough information to support a license renewal. ARCS committee members agreed. 

The ACRS is an independent body of nuclear safety experts that advises the NRC on licensing reviews and other matters.

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