ML20209C398

Responds to NRC Re Violations Noted in Insp Rept 50-346/98-21.Corrective Actions:Developed Rev to Boric Acid Control Program & Work Process Guideline on Plant Leakage

ML20209C398
Person / Time
Site:	Davis Besse
Issue date:	07/01/1999
From:	Campbell G CENTERIOR ENERGY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
1-1188, 50-346-98-21, NUDOCS 9907090282
Download: ML20209C398 (4)

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Davis-Besse Nuclear Power Staten

'l DE Y 5501 North State Route 2 m Oak Harbor. Ohio 43449 4760 Quy G. Compbell 4193214588 Vee President - Nuclear Fax:419321-8337 Docket Number 50-346 License Number NPF-3 Serial Number 1-1188 July 1, 1999 United States Nuclear Regulatory Commission Document Control Desk Washington, D.C. 20555

Subject:

Response to Inspection Report Number 50-346/98021 (DRP)

Ladies and Gentlemen:

The FirstEnergy Nuclear Operating Company (FENOC) is in receipt of Davis-Besse Special Inspection Report (IR) Number 50-346/98021 (DRP) [NRC letter number EA 99-138, FENOC Log Number 5487], dated June 4,1999. The cover letter transmitting the IR identifies two apparent violations and provides FENOC the opportunity to respond, request an enforcement conference, or inform the NRC that information in the IR and Licensee Event Report (LER)98-009 adequately addresses the issues.

The FENOC has reviewed the IR and agrees with the facts as stated. Further, LER 98-009 will be supplemented to reflect updated information collected during the recent mid-cycle outage inspections and from the finite element analysis performed for Pressurizer Spray valve RC-2, all of which has been identified in the IR. We believe these documents contain the information specified on page 2 of the IR 98-021 cover letter, and accordingly, there is no need for a predecisional enforcement conference or an additional response to provide the specified information. However, we would like to provide some clarification of the evaluations performed during the degraded condition identification and our perspective on the classification of the apparent violations.

As clarification, a brief discussion of the operability evaluations that were performed during the time from initial discovery eithe first missing body to bonnet nut from the valve RC-2 up to the completion of the vendor evaluation of the most degraded condition is herein provided. Upon l/

discovery of the first missing body to bonne-t nut from the valve RC-2 on September 1,1998, the Control Room Shift Supervisor requested (via telephone conversation) a preliminary evaluation by Davis-Besse Nuclear Power Station (DBNPS) Design Engineering of the integrity of the valve {0 as a pressure retaining component. The preliminary verbal engineering evaluation addressed seismic, thrust and pressure Icads, and determined the function of the valve to maintain its 9907090282 990701 PDR ADOCK 05000346 G PDR

Docket Number 50-346

. License Number NPF-3

.' Serial' Number 1-1188 Page 2

' integrity would not be affected by one missing body to bonnet nut. This preliminary evaluation provided the Shift Supervisor with reasonable assurance of safety,in accordance with the guidance of NRC Generic Letter (GL) 91-18, Revision 1 (dated October 8,1997) and its attached NRC Inspection Manual, Part 9900: Technical Guidance," Resolution of Degraded and Nonconforming Conditions," and permitted continued operation. A fomial evaluation, with valve manufacturer concurrence, was provided on the next day (again in accordance with the guidance of GL 91-18) which confimied the preliminary evaluation conclusion. At the time the second body to bonnet nut was found to be missing on September 9,1998, the valve was immediately returned to the previously evaluated one body to bonnet nut missing configuration when the first missing nut was replaced, and the Shift Supervisor was apprised of the as-found body to bonnet nut condition. (The second missing nut was replaced on September 10,1999, but was not fully engaged as an effective fastener due to unrecognized thread interference with a previously corroded body to bonnet nut.) Since the body to bonnet nut configuration had been returned to an evaluated condition, there was no current operability issue; however, an evaluation of past operability with two body to bonnet nuts missing was requested. This engineering evaluation was completed, and determined that the valve bolted connection threads would have yielded causing a failure of the body to bonnet joint to maintain its integrity under maximum design pressure condition concunent with seismic loading with two body to bonnet nuts missing.

(The engineering evaluation determined that, absent seismic loading, the valve integrity would l have been maintained for all pressure conditions.) This previously existing condition was reported, as required by 10 CFR 50.72(b)(1)(ii)(B), on September 18,1998. On October 16, 1999, it was found that the body to bonnet nut installed on September 10,1999, was not fully engaged and another degraded nut was discovered to be degraded. Subsequently, on October 17, 1998, all eight body to bonnet nuts were replaced. This resulted in evaluation of this degraded cordgaration for past operability. As stated in LER 98-009, an evaluation of RC-2 in the configuration of having two missing body to bonnet nuts and a third body to bonnet nut in a degraded condition would be performed to assess past operability and safety significance. At no time did the DBNPS knowingly operate or perform any evaluation to operate in a configuration with more than.one body to bonnet nur missing. Upon discovery of each degraded configuration, the action was taken to return to an evaluated and acceptable configuration; i.e., no more than one body to bonnet nut degraded. The detailed evaluation, performed by the valve manufacturer, that determined the valve would not have compromised the integrity of the Reactor Coolant System Pressure Boundary (RCPB) was not performed to allow continued operation in these degraded conditions, but has been used for past operability and safety significance determinations only. The results of the detailed evaluation, which are also noted in IR 98-021, indicated that the valve would have been functional under all design basis conditions, and, therefore, there is no safety significance associated with the degraded configurations of valve RC-2. The DBNPS complied with industry guidance for degraded and nonconforming conditions and does not believe that example C.2(b) of the General Statement of Policy and Procedures for NRC Enforcement Action (NUREG-1600, Rev.1), Appendix B: Supplements - Enforcement Samples, Supplement I- Reactor Operations, is appropriate for consideration in these escalated enforcement actions.

Irrespective of the foregoing, we fully appreciate the importance of the issues raised by the t apparent violations and are committed to effective, comprehensive corrective action. However,

Docket Number 50-346

. License Number NPF-3

.' Serial Number 1-1188 Page 3 we do not believe that the apparent violations are indicative of recurring problems with the material control or the corrective action programs (example C.7 of Appendix B, Supplement I to NUREG-1600, Rev.1). A focused extent of condition walkdown conducted during the recent mid-cycle outage substantiated that the material control issue was isolated. Overall condition identification and resolution evaluations, as confirmed by IR 98-011 (dated September 3,1998) and internal assessments, corroborate the corrective action program was and is effective. The collective lack of sensitivity during maintenance and corrective action for the component bolting represented an unacceptable, but isolated, breakdown in the control of licensed activities to maintain the RCPB. Further, the extensive evaluation performed to determine the effect of the degradation as it related to the valve, and thereby, the RCPB integrity, shows there was ultimately no safety significance (i.e., the integrity of the RCPB would have been maintained during all design basis conditions); however, the regulatory significance remains. Nevertheless, based on the information contained in NRC Enforcement Guidance Document 98-009, "Use of Regulatory Significance for Escalated Enforcement," dated November 25,1998, regulatory significance in the absence of safety, safeguards, or environmental consequence in and of itself does not constitute an escalated enforcement action. Because the failure to properly implement the material control and corrective actions programs were isolated, and the integrity of the RCPB would have been maintained for all faulted conditions, there is no safety, safeguards, or environmental consequence associated with the apparent violations. For these reasons, we suggest escalated enforcement action is unnecessary.

It should be noted that none of the above discussion should be construed to mean that we are minimizing our awareness of the significance of these issues. We understand the concerns as presented and agree that conservative and consistent performance and decision making in each area of plant operation is necessary to ensure public health and safety. As noted in the IR, following the determination that boric acid corrosion was the most likely cause for the missing nuts on the body to bonnet bolting of valve RC-2, a thorough evaluation of the issue was conducted and extensive, effective corrective actions were developed. Greater sensitivity to the effects of boric acid corrosion on plant equipment were noted in the IR and integration of these ,

insights into plant processes and operational philosophy are being institutionalized by:  !

1) developing a revision to the Boric Acid control program and the Work Process Guideline on  !

plant leakage, including the benchmarking of industry standards and practices, to reflect higher standards for monitoring, evaluating, documenting and controlling boric acid leakage; and,

2) providing additional training to management and the technical staff to address the technical issues of boric acid control, the DBNPS Boric Acid Control Program and requirements, lessons learned from the RC-2 event, and industry experience. The DBNPS recognition that some plant maintenance practices required improvement, increased oversight, and additional assessment was also noted in the IR. We will continue to stress the use of a questioning attitude and conservative decision making in managing and resolving identified issues.

It should be further noted that additional corrective actions are presently being conducted or pursued in the area of management oversight, personnel training related to decision making at each level of management, and expectations of personnel in their tolerance of potentially degraded conditions. Initial communication in these areas has been completed, while others are being developed and will be ongoing.

i Docket Number 50-346

, License Number NPF-3

.' Serial Number 1-1188 Page 4 If you should have any questions or require additional information, please contact James L.

Freels, Manager- Regulatory Affairs at (419) 321-8466.

Very truly yours, W 3 h RMC/s Enclosure cc: J. E. Dyer, Regional Administrator, NRC Region UI K. S. Zellers, DB-1 NRC Senior Resident Inspector S. N. Bailey, DB-1 NRC/NRR Project Manager Utility Radiological Safety Board i

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. Docket Number 50-346

• . ' ' Lice'nse NuImber NPF-3 Serial 1-1188 Enclosure COMMITMENT LIST The following list identifies those actions committed to by the Davis-Besse Nuclear Power Station in this document. Any other actions discussed in the submittal represent intended or f

planned actions by Davis-Besse. They are described only as information and are not regulatory I commitments. Please notify the Manager- Regulatory Affairs (419-321-8466) at Davis-Besse of any questions regarding this document or associated regulatory commitments. ,

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COMMITMENTS DUE DATE LER 98-009 will be supplemented to reflect updated information 08/01/1999 collected during the recent mid-cycle outage inspections and from the

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finite element analysis performed for Pressurizer Spray valve RC-2 l I

Greater sensitivity to the effects of boric acid corrosion on plant 09/28/1999 l equipment were noted in the IR and integration of these insights into plant processes and operational philosophy are being institutionalized by '

developing a revision to the Boric Acid control program and the Work Process Guideline on plant leakage, including the benchmarking of industry standards and practices, to reflect higher standards for monitoring, evaluating, documenting and controlling boric acid leakage, Greater sensitivity to the effects of boric acid corrosion on plant 10/01/1999 equipment were noted in the IR and integration of these insights into plant processes and operational philosophy are being institutionalized by providing additional training to management and the technical staff to address the technical issues of boric acid control, the DBNPS Boric Acid Control Program and requirements, lessons learned from the RC-2 event, and industry experience.

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