IR 05000458/1993018
| ML20046C570 | |
| Person / Time | |
|---|---|
| Site: | River Bend  |
| Issue date: | 08/05/1993 |
| From: | Milhoan J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Graham P GULF STATES UTILITIES CO. |
| Shared Package | |
| ML20046C571 | List: |
| References | |
| NUDOCS 9308110166 | |
| Download: ML20046C570 (8) | |
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UNITED STATES ~ 'i ft p*CfCog% ' NUCLEAR REGULATORY COMMISSION , j . , f j' REcioN av - , -
611 RYAN PLAZA DRIVE. SUITE 400 I AR LINGTON. TEXAS 760114064 . " * + * AUG - 51993
Docket: 50-458 . License: NPF-47 i EA 93-167
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Gulf States Utilities j ATTN: P. D. Graham f Vice President (RBNG) -i P.O. Box 220
I St. Francisville, Louisiana 70775
SUBJECT: NOTICE OF VIOLATION AND PROPOSED IMPOSITION OF CIVIL PENALTY - , $100,000 (NRC INSPECTION REPORT NO. 50-458/93-18)
This refers to the inspection conducted April 21 through June 22, 1993, at.the ! River Bend Station (RBS) nuclear power plant, St. Francisville, Louisiana.
. This inspection was conducted specifically to review circumstances surrounding j Gulf States Utilities'(GSU's) discovery on April 19, 1993, during a plant
outage, that Main Steam Isolation Valve (MSIV) IB21*A0VF022B was stuck open.
. A report documenting the results of this inspection was issued on June 29, ! 1993. On July 6, 1993, you and other GSU representatives attended an
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enforcement conference in the NRC's Arlington, Texas office to discuss NRC's ! preliminary conclusion that potentially significant violations.of NRC requirements and plant Technical Specifications had occurred.
I GSU's investigation of the stuck-open MSIV determined that the valve had been l machined in June 1992 and that, following repairs, the clearance between the.
, valve poppet and the lower guide rib was less than specified in vendor ! guidance. GSU's investigation also determined that indications that the valve , was -stuck open were not recognized and pursued by plant operators during valve . ' partial closure tests conducted in February and April 1993. :As a result, the plant was operated from February 27 to April 18, 1993,'a period of 51 days,
with one MSIV stuck open.
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- Based on the information developed during the inspection and the information that GSU provided during the enforcement conference, the NRC has determined -! that the following violations occurred related to the stuck-open MSIV: 1) a j failure in June 1992 to check the dimensions.of-the valve internals-following
machining; 2) failures in February and April 1993 to complete MSIV-l surveillance tests in accordance with RBS procedures; and 3)'a failure from l February 27 to April ~ 18, 1993,. to operate the plant in accordance with the Technical Specifications that require two MSIVs per main steam'line to be operable.
' ' The circumstances surrounding these violations are described in more detail'in - the inspection report.
From the NRC's perspective, the June 1992 failure to ensure that the MSIV post-maintenance internal dimensions were in accordance - f with design, combined with the subsequent failure to pursue MSIV-surveillance f
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o Gulf States Utilities-2-test discrepancies in February and April 1993, is a matter of significant regulatory concern. These violations resulted in an important safety-related component being unable to function as designed to ensure the safety of the facility and to mitigate the consequences of an accident.
In accident conditions, the MSIVs help to minimize both the loss of reactor coolant and the release of radioactive fission products to the environment. As GSU stated during the enforcement conference, certain postulated accidents with a stuck-open inboard MSIV could have resulted in significant radiation exposures to main control room personnel. The NRC acknowledges that the actual effect on facility safety is mitigated by MSIV redundancy, and by the relatively low probability of a failure of the second MSIV in the same steam line.
Nonetheless, because these violations resulted in a significant failure to comply with the plant's Technical Specifications and indicate a breakdown in the control of licensed activities (related to both operations and maintenance), these violations have been aggregated as a Severity Level III problem in accordance with the " General Statement of Policy and Procedure for NRC Enforcement Actions," (Enforcement Policy) 10 CFR Part 2, Appendix C.
These violations occurred primarily because (1) plant personnel involved in MSIV maintenance failed to perform the work properly and in accordance with procedures and (2) plant personnel involved in performing and reviewing the MSIV surveillance tests failed to pursue test discrepancies that should have led them to discover that the MSIV was stuck open. The NRC recognizes that GSU took prompt action to repair the valve and conducted extensive analyses to determine the primary and contributing causes of this event.
GSU's long-term corrective actions, which were discussed in detail during the enforcement conference, include a wide variety of actions to address these causes. These corrective actions are described in GSU's enforcement conference presentation, which was attached to the NRC's July 8,1993 letter documenting the enforcement conference.
As NRC personnel indicated during the conference, these actions appear to encompass the root and contr outing causes.
To emphasize the importance of ensuring that maintenance on safety-related components and systems does not adversely affect operability and the importance of pursuing test discrepancies to ensure the operability of such components and systems, I have been authorized, after consultation with the Director, Office of Enforcement, and the Deputy Executive Director for Nuclear Reactor Regulation, Regional Operations and Research, to issue the enclosed Notice of Violation and Proposed Imposition of Civil Penalty (Notice) in the amount of $100,000 for this Severity Level III problem.
The base value of a civil penalty for a Severity Level III problem is $50,000. The civil penalty adjustment factors in the Enforcement Policy were considered and resulted in a net increase of $50,000.
In considering the civil penalty adjustment factors, the NRC determined that a 50 percent decrease was warranted because the underlying problem (stuck-open MSIV) and associated violations were identified by GSU.
An additional . 50 percent decrease was warranted based on GSU's corrective actions, as }}