ML062060395

NRC Problem Identification and Resolution Inspection Report Clarification Associated with a Non-Cited Violation 05000423/2006006-04

ML062060395
Person / Time
Site:	Millstone
Issue date:	07/12/2006
From:	Price J Dominion Nuclear Connecticut
To:	Document Control Desk, NRC Region 1
References
06-380, IR-06-006
Download: ML062060395 (4)

Text

Dominion Nuclear Connecticut, Inc.

Millstone Power Station Dominion-Rope Ferry Road Waterford, CT 06385 JUL12 U.S. Nuclear Regulatory Commission Serial No.06-380 Attention: Document Control Desk MPS Lic/BAI, RO Washington, DC 20555-0001 Docket Nos. 50-336 50-423 License Nos. DPR-65 NPF-49 DOMINION NUCLEAR CONNECTICUT. INC.

MILLSTONE POWER STATION UNITS 2 AND 3 NRC PROBLEM IDENTIFICATION AND RESOLUTION INSPECTION REPORT Clarification Associated With a Non-Cited Violation 05000423/2006006-04 Dominion Nuclear Connecticut, INC. (DNC) has reviewed the matters identified as Non-Cited Violations (NCV) in the subject inspection report. DNC does not contest the findings documented in the report, however; following the completion of the inspection, additional information related to NCV 05000423/2006006-04 (Failure To Evaluate and Correct Conditions Adverse to Quality Associated with TDAFW Pump) was received from the equipment vendor. DNC believes this information is relevant to the NRC's consideration of the crosscutting implications of the NCV. This matter is further discussed in Attachment 1.

Should you have any questions regarding this matter, please contact Mr. David W. Dodson at (860) 447-1791, extension 2346.

Very truly yours, J.Ala Price Site ice President - Millstone

-:rzýof

Serial No.06-380 Response to NRC PI&R Inspection Report 05000336/2006006 and 05000423/2006006 Page 2 of 2 Attachments: 1 Commitments made in this letter: None.

cc: U.S. Nuclear Regulatory Commission Region I Regional Administrator 475 Allendale Road King of Prussia, PA 19406-1415 Mr. V. Nerses NRC Senior Project Manager Millstone Units 2 and 3 U.S. Nuclear Regulatory Commission, Mail Stop 8 C2 One White Flint North 11555 Rockville Pike Rockville, MD 20852-2738 U.S. Nuclear Regulatory Commission Director, Office of Enforcement Washington, D.C. 20555-0001 Mr. S. M. Schneider NRC Senior Resident Inspector Millstone Power Station

Serial No.06-380 Attachment I Clarification Associated With a Non-Cited Violation 05000423/2006006-04 Millstone Power Station Units 2 and 3 Dominion Nuclear Connecticut, Inc. (DNC)

Serial No.06-380 Attachment 1 Page 1 of 1 Restatement of NCV: - 05000423/2006006-04, Failure To Evaluate and Correct Conditions Adverse to Quality Associated with TDAFW Pump "The inspectors identified a Green NCV of 10 CFR 50, Appendix B, Criterion XVI, "Corrective Actions," for the failure to take effective corrective action to prevent a repeat failure of the Unit 3 turbine-driven auxiliary feedwater (TDAFW) pump. Specifically, following identification and documentation of excessive internal stuffing box wear, which was identified following an overspeed trip event that occurred in April 2005, the licensee failed to fully evaluate this condition which was later documented as a contributing cause to a recurring failure that occurred on January 9, 2006. The licensee entered this condition into their corrective action program as CR-06-00244. Corrective actions for this issue included repacking of the TDAFW pump governor control valve, repair of a cam plate, and plans to conduct a stuffing box repair within three months of the January 2006 pump failure...."

Clarification Prior to the NRC inspection, DNC had completed its investigation (Root Cause Evaluation M-06-00244) and concluded that a contributing cause to the Unit 3 TDAFW pump trip was TDAFW pump governor control valve stuffing box (3MSS*MCV5) wear.

The initial conclusion, that the stuffing box wear was a contributing cause, resulted from an investigation into what was causing packing wear. Since the available documentation indicated that the packing stuffing box was larger than the value specified in the Vendor Technical Manual, it was decided that the worn stuffing box might be contributing to the packing wear.

However, questions regarding the dimensional tolerances of the stuffing box were unresolved and discussions between representatives of DNC and the Vendor were ongoing during the course of the NRC's inspection. Subsequent to the issuance of the NRC inspection report, the TDAFW pump vendor concluded that the Millstone Unit 3 TDAFW pump governor control valve (3MSS*MCV5) stuffing box should have a bonnet bore ID of 1.047" to 1.077" not to exceed 1.100". The bonnet bore was recently checked using calibrated equipment and found to be 1.0715" to 1.0765". These measured dimensions are within the tolerances specified by the vendor.

Because the TDAFW pump governor control valve (3MSS*MCV5) stuffing box bonnet bore ID remained within tolerances specified by the vendor, the stuffing box is acceptable as is. Consequently, the TDAFW pump governor control valve stuffing box (3MSS*MCV5) wear is no longer considered to have been a contributing cause to the Unit 3 TDAFW pump trip of January 9, 2006. The corrective action plan associated with the root cause evaluation has been updated based on this information. A change to the Vendor Technical Manual has also been approved to delete the misleading stuffing box dimensions.

DNC trusts that this clarification will assist the NRC in any future consideration related to this NCV.