NRC Issues Confirmatory Action Letter Inspection Report

-

1519

NRC Issues Confirmatory Action Letter

Inspection Report

for San Onofre Nuclear Generating Station

 

The NRC has preliminarily determined that the inadequate design of the steam generators at San Onofre Nuclear Generating Station was a violation of low to moderate safety significance.

The preliminary finding is identified in aninspection report

documenting the NRC’sassessment of Southern California Edison’s response to a Confirmatory Action Letter issued on March 27, 2012. The CAL documented actions that Edison agreed to take in response to the Jan. 31, 2012,

steam generator tube leak at its Unit 3 reactor.

 

The NRC conducts inspections in order to verify that the

commitments made in the licensee’s response to a CAL have been completed.

Such inspections can lead to findings such as those cited in this instance.

In addition, NRC has issued a Notice of Nonconformanceto Mitsubishi Heavy Industries for problems associated with the design of the steam generators. Mitsubishi has 30 days in which to respond in writing. The company can contest the notice, or provide additional information explaining corrective actions they have taken or plan to take to address the nonconformance.

 

The NRC uses color-coded inspection findings to assess the risk significance of violations. The colors start with green, then increase to white, yellow or red, commensurate with the safety significance of the issues involved. The NRC has preliminarily determined that the inadequate computer modeling

that led to the deficient design of the steam generators is a white finding of low to moderate safety significance in Unit 3. A green finding was issued for Unit 2

because its tubes did not lose integrity.

 

Two minor violations were also identified associated with the review of proposed changes to limit plant power to 70 percent.Edison has 10 days in which to notify the NRC of its intentions of whether it will accept the violation, request a regulatory conference or submit information in writing before a final determination is made on the proposed violation.