IR 05000346/1998021

Refers to NRC Insp Rept 50-346/98-21 Conducted on 980901- 990513 & Forwards Nov.Two Violations Identified Involving Failure to Maintain Design of Valve & Inadequate C/A for Degraded Condition Cited in Encl NOV

ML20210P777
Person / Time
Site:	Davis Besse
Issue date:	08/06/1999
From:	Dyer J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:	Campbell G CENTERIOR ENERGY
Shared Package
ML20210P784	List: IR 05000346/1998021 ML20210P798
References
50-346-98-21, EA-99-138, NUDOCS 9908130081
Download: ML20210P777 (4)

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. UNITED STATES rug % , NUCLEAR REGULATORY COMMISSION

[' s REGION iil si j 801 WARRENvlLLE ROAD

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o August 6, 1999 EA 99-138 Mr. Guy l Vice President - Nuclear, Davis-Besse l FirstEnergy Nuclear Operating Company {

Davis-Besse Nuclear Power Station j 5501 North State Route 2 Oak Harbor, OH 43449-9760 SUBJECT: l NOTICE OF VIOLATION (NRC INSPECTION REPORT 50-346/98021)

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Dear Mr. Campbell:

This refers to the NRC inspection conducted at FirstEnergy's Davis-Besse Nuclear Power Plant i

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from September 1,1998 to May 13,1999. The purpose of the inspection was to review the circumstances surrounding your staff's discovery of missing body-to-bonnet nuts on a pressurizer spray valve. The report documenting our inspection was sent to you by letter dated June 4,1999. NRC inspectors discussed the significance of the issue with members of your staff at the inspection exit meeting on May 13,1999. Our June 4,1999, letter offered you the option to either respond to the apparent violation, request a predecisional enforcement conference, or inform the NRC that the information in our inspection report and your Licensee Event Report (LER) 346/98-009 adequately addresses the issue. Your July 1,1999, letter stated that the inspection report and LER adequately addressed the issue and that you did not '

request a predecisional enforcement conference.

The NRC determined that two violations of NRC requirements occurred. This determination was based on the: (1) Information developed during the inspection; (2) information your staff provided during the inspection: and (3) information your staff documented in LER 346/98-009.

The violations involving failure to maintain the design of the valve and inadequate corrective action for the degraded condition are cited in the enclosed Notice of Violation (Notice) and the circumstances surrounding the violations are described in the inspection report.

While monitoring a packing leak on a pressurizer spray valve, a worker identified that one of the eight body-to-bonnet nuts was missing. While your maintenance staff formalized plans to replace the nut, your engineering staff determined that the valve remained functional at design loads with the nut missing. Your maintenance and engineering staff did not do a rigorous evaluation of the cause for the missing nut. Instead they incorrectly determined that a contractor removed the nut to facilitate the installation of equipment for a temporary sealant repair of the packing leak. While replacing the missing nut, a worker identified that a second nut was missing; this nut was also replaced.

During a subsequent outage, a worker noted a gap between one of the replacement nuts and the bonnet. This gap was due to a replacement nut being installed over remnants of a corroded nut. Additionally, a worker found that a third nut was degraded (corroded away) by

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, approximately 30E A subsequent evaluation determined that three of the nuts were carbon steel and were susceptible to boric acid induced corrosion. The remaining five nuts were stainless steel and were not susceptible to boric acid induced corrosion. An engineering analysis performed by your staff determined that with two nuts missing, safe shutdown earthquake loads concurrent with maximum design pressure would have resulted in failure of the valve's body-to-bonnet joint. The failure would have resulted in a nonisolable reactor coolant system leak (a small break loss of coolant accident) at the failed joint. A subsequent vendor analysis concluded that the valve would have remained functional under all accident

. conditions.

In your July 1,1999, letter, you stated that: (1) your staff complied with industry guidance for degraded and nonconforming conditions; (2) a detailed evaluation demonstrated the reactor-coolant system was operable; and (3) that there was no regulatory significance due to the lack of safety, or environmental consequence. The NRC acknowledged that the as-found condition may not have had actual safety, or environmental consequence. Additionally, we acknowledge that each time a missing nut was found your staff attempted to restore the valve to a safe

. configuration. However, your staff failed to do a rigorous evaluation of the missing nuts in a timely manner, which resulted in delays in: (1) identifying that carbon steel nuts were installed, contrary to the design specifications of the valve; (2) determining that the missing carbon steel nuts had corroded due to a highly corrosive boric acid environment; (3) initiating actions to

. identify the extent of the degraded condition; and (4) implementing more extensive corrective actions to address the degraded and nonconforming condition. Additionally, your maintenance staff missed another opportunity to identify the corrosion problem when they placed a nut on a remnant of a nut that was believed missing. A detailed evaluation of the degraded condition by the vendor was required to demonstrate that the valve would have remained functional under all conditions. The NRC has concluded that your staff's failure to control the design of a reactor-coolant system pressure boundary component and to thoroughly evaluate and correct degraded

. conditions in a timely manner did have a credible potential to impact plant safety. Therefore, the violations are categorized in the aggregate in accordance with the " General Statement of Policy and Procedure for NRC Enforcement Actions (Enforcement Policy)," NUREG-1600, as a Severity Level 111 problem.

In accordance with the Enforcement Policy, a base civil penalty in the amount of $55,000 was considered for this Severity Level 111 problem. Because your facility has not been the subject of escalated enforcement actions within the last two years, the NRC considered whether credit '

was warranted for Corrective Action in accordance with the civil penalty assessment process in Section VI.B.2 of the Enforcement Policy. You were given credit f:,r initiating effective corrective actions once you identified the root cause of the dep9dation.. Your corrective actions included: (1) training sessions with maintenance personnelio enhance knowledge of the effects of boric acid on materials; (2) a review of boric acid corrosion procedures which resulted in program enhancements; (3) the inspection of pressure retaining bolted connections with a potential for the installation of fasteners of nonconforming material; and (4) resolution of the pressurizer spray valve packing problems.

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Therefore, to acknowledge your comprehensive correction of the violations, I have been authorized, after consultation with the Director, Office of Enforcement, not to propose a civil penalty in this case. However, significant violations in the future could result in a civil penalty.

The NRC has concluded that information regarding the reason for this violation; the date when i you will achieve full compliance; and the corrective actions taken to correct the violation and i prevent recurrence are already adequately addressed on the docket in Inspection Report 50-346/98021 and LER 346/98-009. Therefore, you are not required to respond to this letter unless the description therein does not accurately reflect your corrective actions or your {

position. In that case, or if you choose to provide additionalinformation, please follow the instructions specified in the enclosed Notice.

In accordance with 10 CFR 2.790 of the NRC's " Rules of Practice," a copy of this letter and the enclosure will be placed in the NRC Public Document Room.

Sincerely, Original signed by J. Caldwell for J. E. Dyer Regional Administrator Docket No. 50-346 License No. NPF-3 Enclosure: Notice of Violation cc w/ encl: J. Stetz, Senior Vice President - Nuclear J. Lash, Plant Manager J. Freels, Manager, Regulatory Affairs M. O'Reilly, FirstEnergy State Liaison Officer, State of Ohio R. Owen, Ohio Department of Health C. Glazer, Chairman, Ohio Public Utilities Commission DOCUMENT NAME: G:\EICS\99-138.It4.wpd To receive a copy of this document, Indicate in the box: "C" = Copy without attachment / enclosure "E" = Copy with attachment / enclosure "N =

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