ML19319C117
| ML19319C117 | |
| Person / Time | |
|---|---|
| Site: | Oconee, Davis Besse  |
| Issue date: | 02/19/1975 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19319C115 | List: |
| References | |
| NUDOCS 8001310478 | |
| Download: ML19319C117 (2) | |
Text
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TOPICAL REPORT EVALUATION Report Number:
BAU-10100 (non-proprietary)
Report
Title:
Reactor Vessel Materials Surveillance Program - Cocpliance with 10 CFR 50, Appendix H, for Oconee Class Reactors Report Date:
October 1974 Originating Organization:
Babcock and Wilcox Reviewed By:
}bterials Engineering Branch SUID!ARY OF TOPICAL REPORT This report describes two material surveillance prograns developed for recent B & U 177 fuel assembly reactors (Ocence class).
A basic program is described for vessels expected to retain adequate toughness throughout their life. A modified progran is described for naterials that may have marginal Charpy upper shelf levels at end of life.
For both programs specimens are machined from as-fabricated base, weld and heat-affected-7.one materials from the tuo heats of steel used in the reactor vessel beltline that have the greatest potential for limiting operation.
Specimens are placed in six capsules, located approxinately 2.25 inches from the p,ressure vessel inner wall and in the core midplane region. All capsules'contain the required nucher of tensile specimens, dosinctera and tenperature monitors.
The basic program actually contains core Charpy specimens than is required.
Beltline regien nuterials of some Oconee class vessels may have marginal irradiated Charpy upper shelf energy levels (near to or belou 50 ft lbs) late in the plant design life. A todified surveillance progran is reconcended for these vessels. The codified program is designed to provide evidence that the irr1diated materials have retained sufficient fracture toughness to assure vessel integrity even if the upper shelf energy is predicted to fall below 50 ft lbs.
For this program eight 1/2 T compact tension specimens made of the limiting material are substituted for the usual excess Charpy specimens in each of three capsules.
REGULATORY EVALUATION Both the basic and codified reactor vessel material surveillance programs are in compliance with Appendix H to 10 CFR Part 50, " Reactor Vessel Material Surveillance Program Requirements," and ASTM Specification E 185-73, " Surveillance Tests for Nuclear Reactor Vessels."
These programs, with appropriate conservatism applied to the evaluation of test results, will provide an adequdte basis for ascertaining radiation effects on the vessel materials.
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o The modified surveillance pr,ogram developed for those-Oconee class vessels for which the transverse upper shelf Charpy energy of any belt-line material is predicted to be reduced by irradiation to values close to or below 50 ft lbs, appears to be consistent with current state-of-the-art procedures for determining fracture toughness.
This program will be useful in providing assurance of vessel integrity for vessels having materials with marginal Charpy upper shelf levels late in the plant design life.
REGULATORY FOSITION Both the basic and modified material surveillance programs described in BAW-10100 conform to the requirements of Appendix 11 to 10 CFR Part 50 and AS'D1 S"ecification E 135-73 and therefore, may be referenced in SARs for B 5.W 177 fuel assenbly reactors (Oconee class) and other new plants.
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