ML20136E731

Comment Supporting Proposed Generic Communication, Effectiveness of Ultrasonic Testing Systems in Inservice Inspection Programs

ML20136E731
Person / Time
Site:	Beaver Valley
Issue date:	03/03/1997
From:	Jain S DUQUESNE LIGHT CO.
To:	NRC
References
FRN-61FR69120 61FR69120-00015, 61FR69120-15, NUDOCS 9703130307
Download: ML20136E731 (3)

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l::0:A Chief, Rules Review and Directives Branch U. S. Nuclear Regulatory Commission Mail Stop T-6D-69 Washington, DC 20555-0001 i

Subject:

Beaver Valley Power Station, Unit No. I and No. 2 BV-1 Docket No. 50-334, License No. DPR-66 BV-2 Docket No. 50-412, License No. NPF-73 Proposed Generic Communication; Effectiveness of Ultrasonic Testing Systems in Inservice Inspection Programs Duquesne Light Company (DLC)is responsible for the operation of Beaver Valley Power Station Units 1 and 2. DLC has reviewed the proposed generic letter which was published in the Federal Register on December 31,1996 (61 FR 69120). The proposed generic letter would aid the Nuclear Regulatory Commission (NRC) in determining if addressees are taking appropriate action to qualify future ultrasonic testing (UT) examinations. DLC hereby submits the following comments.

DLC endorses the Nuclear Energy Institute comments provided to the NRC by separate letter dated February 21, 1997, and, in addition, provides several specific comments.

In the request for public comment for the proposed generic letter, the NRC questions the effectiveness of current ultrasonic inspection practices. It is not clear whether the NRC plans to mandate the use of Appendix VIII or allow for the irnplementation of the industry PDI (Performance Demonstration Initiative) program as an approved alternative to Appendix Vill. The NRC endorses the PDI program as providing an acceptable level of quality and safety in the ' Description of Circumstances' j section of the generic letter, yet suggests that rulemaking will be based upon the 1995 g Edition of ASME Section XI, Appendix VIII. If the 1995 Edition of Appendix VIIIis endorsed, the industry will be required to take exception to several portions of the rule since certain aspects of Appendix VIII,1995 Edition are not technically attainable. DLC supports the technical position response on this issue developed by the EPRI PDI.

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Besver Vclicy Power Station, Unit No. I and No. 2 Proposed Generic Communication; Effectiveness of Ultrasonic Testing Systems in Inservice Inspection Programs Page 2 l The DLC position is based on the defense-in-depth that is designed into nuclear power plants through code design margins applied during fabrication and construction, code design margins incorporated into the current flaw sizing and evaluation procedures, and the leakage monitoring programs employed by utilities during operation. If there is i to be a substantive change to the inspection qualification and recording criteria, there l needs to be a commensurate change in the flaw sizing acceptance criteria and the other regulatory requirements which are based upon an assumed flaw that would be undetected (such as the flaw assumptions used in the Pressurized Thennal Shock (PTS) evaluation methodology). Since the size of an undetected flaw would be reduced under both PDI 1 and Appendix VIII, changes would need to be made in this area also.

The other DLC concern involves the areas of the plant to which this methodology would be applied. The qualification procedures and mock-ups are very specific to the materials and geometries involved. Therefore, DLC questions whether the areas to be inspected will result in risk reduction. Specifically, by increasing our confidence level in i the inspections perfonned of the reactor vessel and safety related piping identified in the current code, it is not clear whether a significant change to the risk associated with the component with or without inspections will result. If there is not a change to the relative )

risk significance of the area being inspected this can be attributed to one of two factors; i

1) the increase in the inspection capability is not safety significant (probability of failure has not changed and therefore current techniques a e as effective) or 2) the component's relative safety significance based upon contribution to core damage is so low that its contribution to the safety posture of the plant is inconsequential. If the first is true, then Appendix VIII or PDI inspections are not improving the safety posture of the plant and should not be implemented since they have little or no value added. If the second is true, the area being inspected is not safety significant and should be removed from the inspection programs.

Therefore, for the Appendix VIII or PDI enhanced inspection programs to be meaningful, a commensurate reduction ht the contribution to core damage frequency should be obtained. If the locations fo'; application of this inspection methodology are unaffected by the improved inspection tachniques, then the current inspection techniques should be considered acceptable in these locations. If the inspection methodologies of Appendix VIII and/or PDI are employed, il e analytical tools used to evaluate the results of the inspections should utilize the sizing hformation and probability of detection of a critical size flaw in that analysis. Improvement in inspection and detection capability must be accompanied by inspecting the appropriate safety significant components and integrating the new inspection / detection limits into all aspects of the evaluation process (code flaw evaluation and sizing methodologies).

Beaver Valley Power Station, Unit No. I and No. 2 Proposed Generic Communication; Effectiveness of Ultrasonic Testing Systems in Inservice Inspection Programs Page 3 Thank you for the opportunity to comment on this issue. If you have any questions ,

on this submittal, please contact Mr. Roy K. Brosi, Manager, Nuclear Safety Department, (412) 393-5210.

Sincerely, Sushil C. Jain 1

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