ML18139A606
| ML18139A606 | |
| Person / Time | |
|---|---|
| Site: | Surry, North Anna  |
| Issue date: | 07/21/1980 |
| From: | Brown S VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | Snaider R Office of Nuclear Reactor Regulation |
| References | |
| REF-GTECI-A-12, REF-GTECI-ES, RTR-NUREG-0577, RTR-NUREG-577, TASK-A-12, TASK-OR 480, 498, NUDOCS 8007310421 | |
| Download: ML18139A606 (2) | |
Text
e Vepco VIRGINIA ELECTRIC AND POWER COMPANY, RICHMOND, VIRGINIA 23261 Mr. Richard Snaider Generic Issues Branch U.S. Nuclear Regulatory Commission Washington, D.C.
20555
Dear Mr. Snaider:
July 21, 1980
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Serial. Nos. 480 498 PSE&C/JMM:bmt Docket Nos. 50-280 50-281 50-338 50-339 License Nos. DPR-32 DPR-37 NPF-4 NPF-7 Vepco has revi~wed NUREG-0577 Potential for Low Fracture Toughness and Lamellar Tearing on PWR Steam Generator and Reactor Coolant Pump Supports dated October 1979, *and the enclosure to NRC 1 etters of May 19, 1980 and May 20, 1980 which dealt with implementation of a proposed review procedure based on NUREG-0577.
We have the following comments on the proposed review procedure entitled, "General Operating Reactor Review Procedure and Acceptance Criteria."
- 1.
Item 2, Part I.A. Materials having minimum specified yield strength of 180 ksi or less:
For these materials NOTT or CVN acceptance standards are proposed.
If materials do not meet one of these standards, additional analysis is required to assure "failed" support integrity.
It is proposed by Vepco that a third method of demonstrating fracture toughness be per-mitted before requiring "failed" support integrity analysis.
The NRC should allow the appl.ication of linear elastic fracture mechanics tech-niques for the analysis of critical flaw size of components, where it can be shown that an adequate inspection program is available and capable of requisite flaw detection. This method of analysis would be based on utilization of Kid data from the literature or calculated Kid values where such data for the heats of material in question are unavailable. Tech-niques for such an analysis are shown or referenced in NUREG 0577 Section 4.0 This analysis would allow structures to be considered adequate where it could be demonstrated that flaws which would be of critical size under maximum load conditions were not in the structure, and where fatigue crack growth was not operative. This method of analysis would be partic-ularly appropriate for low strength materials of lower toughness where stress levels under maximum load conditions are below yield strength, and where material geometries permit adequate inspection.
e VIRGINIA ELECTRIC AND POWER COMPANY TO SHEET NO.
- 2.
Item 2, Part II - Stress corrosion cracking for materials with minimum yield strength greater than.120 KSI:
Since the topic of stress cor-rosion cricking as it relates to the parameter KISCC was not addressed by NUREG-0577, Vepco requests an extension of the review period to September 15, 1980 to allow proper.review of this topic.
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