ML083010233

Electric Power Research Institute MRP-139 Deviation Notification

ML083010233
Person / Time
Site:	Millstone
Issue date:	10/27/2008
From:	Price J Dominion Nuclear Connecticut
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
08-0523, MRP-139
Download: ML083010233 (3)

Text

Dominion Nuclear Connecticut, Inc.

"(100 Dominion Boulevard, Glen Allen. Virginia .!\060

\\ "h :\ddress: www.dom.com October 27, 2008 U.S. Nuclear Regulatory Commission Serial No. 08-0523 Attention: Document Control Desk NLOS/GAW RO One White Flint North Docket No. 50-423 11555 Rockville Pike License No. NPF-49 Rockville, MD 20852-2738 DOMINION NUCLEAR CONNECTICUT, INC.

MILLSTONE POWER STATION UNIT 3 ELECTRIC POWER RESEARCH INSTITUTE MRP-139 DEVIATION NOTIFICATION In accordance with the Nuclear Energy Institute (NEI) Guideline for the Management of Materials Issues (NEI 03-08, Rev 1), Dominion Nuclear Connecticut, Inc., (DNC) is providing notification of a deviation from the Electric Power Research Institute (EPRI)

Materials Reliability Program (MRP): Primary System Piping Butt Weld Inspection and Evaluation Guidelines (MRP-139). This notification is being sent consistent with the industry initiatives to provide timely communications to NRC staff regarding conformance with industry guidance. This notification is for information only and no response is requested.

The deviation relates to the mandatory visual examination requirements contained in MRP-139. Specifically, MRP-139 requires bare metal visual examination of the nozzle to safe end welds of both the inlet and outlet of the Reactor Pressure Vessel (RPV) during Millstone Power Station Unit 3 (MPS3) refueling outage 12 (3R 12) in the fall of 2008. These weld locations contain Alloy A 182 that is susceptible to primary water stress corrosion cracking (PWSCC). The required visual inspections would result in almost 30 rem dose impact. Accordingly, MPS3 has developed a basis for waiving the visual examinations while concurrently increasing volumetric inspection frequency. This strategy achieves the same objective and intent of the original MRP-139 requirement.

The technical justification demonstrates that any small flaws undetected by the volumetric ultrasonic test (UT) examinations would remain within the acceptable limits of the ASME Code for the period between qualified UT examinations. The RPV inlet and outlet nozzles were most recently inspected from the inside diameter by UT examination during the spring of 2007 3R11. No recordable indications were identified. In accordance with the alternative plan described in the deviation report to the EPRI Materials Reliability Program, the outlet nozzle will next be inspected by UT examination in the spring of 2010 3R13 and the inlet nozzle will next be inspected by UT examination in the fall of 2011 3R14. Also in accordance with the alternative plan, subsequent inspections will be performed every two refueling outages for the RPV outlet nozzle and every three refueling outages for the inlet nozzle. If the nozzle

Serial No. 08-0523 Docket No. 50-423 MRP-139 Deviation Notification Page 2 of 3 welds are mitigated to preclude PWSCC growth, the inspection plan will be modified in accordance with MRP guidance.

The technical justification for the deviation has been prepared and concurrence by an independent third party materials expert has been obtained in accordance with NEI 03-08 requirements. The deviation has been processed through the station corrective action program and is documented in plant records. It is expected that this deviation will continue while the MRP-139 requirement remains in effect, or until the locations are mitigated to prevent propagation of potential PWSCC.

If you have any questions regarding this notification, please contact Mr. Geoffrey Wertz at (804) 273-3572.

Sincerely, an Price President - Nuclear Engineering Commitments made in this letter: None cc: U.S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406-1415 Ms. C. J. Sanders Project Manager - Millstone Power Station U.S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Mail Stop 0-8B3 Rockville, MD 20852-2738 Ms. T. M. Mensah, Senior Project Manager Special Projects Branch Division of Policy and Rulemaking U.S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Mail Stop 0-12E5 Rockville, MD 20852-2738

Serial No. 08-0523 Docket No. 50-423 MRP-139 Deviation Notification Page 3 of 3 NRC Senior Resident Inspector Millstone Power Station