ML20078A110
| ML20078A110 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 09/30/1991 |
| From: | Caine T, Ranganath S, Stevens G GENERAL ELECTRIC CO. |
| To: | |
| Shared Package | |
| ML20078A108 | List: |
| References | |
| GE-NE-523-95-09, GE-NE-523-95-0991-R0, GE-NE-523-95-9, GE-NE-523-95-991-R, NUDOCS 9110070245 | |
| Download: ML20078A110 (46) | |
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i HL-1836 002240 Septen.ber 30, 1991 U.S. Nuclear Regulatory Commission ATIN.: Document Control Desk Washington, D.C.
20555 PLANT HATCH - UNIT 2 NRC 00CK2T 50-366 OPERATING LICENSE NPF-5 VJ!lli E FEEQWATER NM Zi[
flNAL FRACTURE ME.[1]ANICS ANALYSIS Gentlemen:
On January 21, 1991, Georgia Power Company (GPC) submitted an interim feedwater nozzle fractcre mechanics analysis (FMA) for Plant Hatch Unit 2 which predicted that an assumed 0.25 inch crack would propagate to greater than one inch in 32 years using the ASME Code Section XI crack growth relationships.
This represented a substantial improvement over the original analytical predictions primarily as a result of using an updated operating iistory for cycle counts and cycle count projections.
- Ilowever, the improved results did not show full compliance with the requirements of NUREG-0619.
GPC committed to perform further analyses and submit a final FMA which demonstrates full compliance with NUREG-0619.
GPC hereby provides the final feedwater nozzle fracture mechanics assessment for Plant Hatch Unit 2.
The enclosed General Electric Company Report No.
GE-NE-523-95-0991, Revision 0 (Enclosure 1) provides final results showing compliance with NRC requirements regarding reactor vessel feedwater nozzle crack growth, as specified in NUREG-0619 and amended by Generic letter 81-11.
The analysis shows that, using NUREG 0619 guidelines, an assumed 0.25 inch crack will not propagate to greater than one inch over the 40 year licensed life of the plant.
Thus, Plant Hatch Unit 2 is in full compliance with the crack growth analysis requirements of NUREG-0619.
As requested by your letter dated July 9, 1991, the latest Unit 2 operating history, up to the Spring of 1991, has been incorporated into the thermal cycle projections.
The new data is not significantly different from the previous record of 1985 through 1990, and demonstrates continued improvement in plant operation with respect to thermal duty. Additionally, Appendix B of the enclosed report addresses the theoretical and computational bases justifying the derivation of the stress intensity factor equation for the 3-D nozzle corner crack.
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Georgia Poe.er d U.S. Nuclear Regulatory Commission September 30, 1991 Page Two Appendix B also includes a discussion of how two elasticity problems with different geometries are manipulated to arrive at a solution for the 3-D nozzle corner crack problem.
GPC believes that the transmittal of the attached report satisfies our prior commitments and is sufficient to support final closure of the feedwater nozzle crack growth analysis issue for Hatch Unit 2.
Should you have any questions, please contact this office.
Sincerely,
/ p-J. T. Beckham, Jr.
JKB/cr 002240
Enclosure:
General Electric Report No. GE-NE-523-95-0991 cc: fgorcia Power Company Mr. H. L. Sumner, General Manager - Nuclear Plant NORMS U.S. Nuclear Reaulatory Commission. Wash.in91on. D.C.
Mr. K. Jabbour, Licensing Project Manager - Hatch U.S. Nuclear Renulatory Commission. Reaion 11 Mr. S. D. Ebneter, Regional Administrator Mr. L. D. Wert, Senior Resident inspector - Hatch 4
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4 ENCLOSURE PLANT HATCH - UNIT 2 NRC DOCKET 50-366 OPERATING LICENSE NPF-5 UNIT 2 FEEDWATER N0ZZLE FINAL FRACTURE MECHANICS ANALYSIS
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