ML19329A240
| ML19329A240 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 04/17/1978 |
| From: | Shao L Office of Nuclear Reactor Regulation |
| To: | Lear G Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8001020737 | |
| Download: ML19329A240 (2) | |
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I gB MEMORANDUM FOR: > G. Lear, Chief, Operating Reactors Branch 4
. Division of.Operatina Reactors FROM:
L. C. Shao, Chief, Engineering Branch, Division of Operating Reactors
SUBJECT:
OCONEE UNIT 1 - PRESSURE-TEMPERATURE OPERATING LIMITS (TAC 7375)
Plant Name: Oconee, Unit 1 j
NSSS Vendor: Babcock and Wilcox Docket Number: 50-269 /-
4 Operating Reactors Branch and Project Manager: ORB-4, M. Fairtile l
Operational Technology Branch Involved: Engineering Branch Description of Task: Review Change to Pressure-Temperature Operating j
Limits Due Date: Api 11 14, 1978 Review Status: Complete In letter dated February 21, 1978, Duke Power Company submitted a proposed amendment to Technical Specification 3.1.2 for Oconee, Unit i regarding pressure-temperature operating limits. The new limits were proposed for operation through 8 EFPY. They were based on the results of tests on Capsule OCI-E specimens kecently renoved from Oconee, Unit 1.
These test results are reported in BAW-1436, September 1977. Copies of this report were enclosed for NRC review.
We have reviewed the BAW-1436 report. Data shows that weld metal is l
the limiting material. The weld metal in Capsule OCI-E is identified i
as Proceq25 m/cmure Qualification (PQ) number WF-ll2. At a fguence of 1.5 x 10 4 it showed an increase in RTNDT of 124 F.
This report
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also includes fluence calculations based on data from dosimeters removed from the reactor vessel with Capsul OCI-E. The maximus I
fluence (E '.1 mev) on the vessel wgli at T location after 10 EFPY is calculated to be 3.2 x 1030 m/cm'. From our review we conclude that the mechanical properties data and the fluence values reported.
are valid.
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In letter dated August 31,1977, Duke Power Company submitted information to NRC on Oconee 1 reactor vessel materials. This letter lists six different weld metals in tLe vessel beltline region; WF-25, SA-1073 SA-1135, SA-1229 SA-1430, SA-1493 and SA-1585. All of these welds are estimated to receive the maximum fluence on the vessel wall. Also, wa note that the surveillance l_
weld, WF-112, is not identigl to any of these welds; i.e., it i
was not made from the same weld wire and flux.
Therafore, we feel I
that the upper limit damage predictions of Regulatory Guide 1.99, Revision i should be used to establish the changes in RTg used in calculating the pressure-temperature operating limits. The operating limits submitted by Duke Power Company are calculated for an RT &T of 1650F at the end of the operating period. Using i
the Regulatory Guid to predict radiation damage and assuming an initial RTng of 20 fluence of T.9 x 10 g,m/cm2we calculate that RTrgy will be 1650F at a The reactor vessel wall at T
location is expected to reach this fluence level in 6 EFPY.
From our review we conclude that the proposed pressure-temperature operating limits and changes to Technical Specification 3.1.2 are acceptable through only fEFPY instead of 8 EFPY proposed by Duke Power Company. For this operating period the proposed pressure-temperature operating limits are in accordance with Appendix G, 10 CFR Part 50. Osmp11ance with Appendix G In es b11shing safe operating limitations will ensure adequate safe rgins during operation, testing, maintenance and postulated ident conditions and constitcte an acceptable basis for satisfying the requirements of NRC General Design Criterion 31. Appendix A,10 CFR Part 50.
L. C. Shao. Chief Engineering Branch Division of Operating Reactors cc:
V. Stello R. Mattson J. Knight
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