ML14192A178
| ML14192A178 | |
| Person / Time | |
|---|---|
| Site: | Robinson  |
| Issue date: | 05/04/1981 |
| From: | Varga S Office of Nuclear Reactor Regulation |
| To: | Jackie Jones Carolina Power & Light Co |
| References | |
| NUDOCS 8105150285 | |
| Download: ML14192A178 (3) | |
Text
[ILSTRIBUT1ON' Docketi NRC'PDR L tDR 0TERA
- MAY, 4
e NSIC ORB#1 Rdg 9 ocket No. 50-261 isenhut OELD 9V UIL/
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ACRS-10 3 1981rZ Mr. J. A. J6-es SVarga M
T Senior Executive Vice President DNeghbor Carolina Pwer and Light company CParrishr 336 FayettewItle Street M o Raleigh, North Carolina 27602
Dear Mr. Jones:
The NRC staff has been reviewing the subject of control rod guide thimble wear in pressurized water reactors. Based on our review, we haee concluded that this issue is resolved for the 15 x 15 fuel assemblies designed by Exxon for H. B. Robinson, Unit No. 2.
The propensity for guide thimble wear in Exxon reload fuel should be, to a frrst approximation, equivalent to that in Westinghouse fuel in the same plant. Examinations of Exxon-iFuel th~t was discharged from your facility, as reported by Exxon letter dated February 25, 1980, revealed no through wall wear nor major differences in the wear from that wear which was meas ured on Westinghouse fuel that was discharged from Pt. Beach, Units Nos. I and 2.
The Exxon examinations were pV formed-on 5 fuel assemblies that had been unded control rod banks for one cycle of reactor operation., One assembly was f em Cycle'4 and four assemblies were f 4 Cycle 5 operation.
Of the 100 guide'thimple tubes examined by an eddy current testing (ECT) method, only 11 had detectable wear (i.eJ, wear greater that about 3 mils local wall thinning). The ECT measurements did not reveal the azimuthal dis tribution of the wear, but if the worst Wear that was detected had been concentrated on one side of the guide thimble tube wall, it would have indicated that a minimum of 23% of the wall thickness remained.
We conclude that (a) the degree of Wbar measured by Exxon is acceptable, (b) the degree of wear in the Exxon fuel is similar to that in Westinghouse fuel, which we have found acceptable, and (c) the issue of guide th mble wear in Exxon-fueldd Westinghouse-NSSS plants has been adequately resolved.
Sincerely, Original signed byt
- 7.
- Varga Steven A. Varba, Chief Operating Reactors Branch #1 Division of Licensing OFFICE) 0 O
DL L
SURNAME N
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BATE
/81.........................................
NRC FORM 318 (10/80) NRCM 0240 OFFICIAL R CORD COPY
- USGPO:1980-329824
oC UNITED STATES 4"
NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 May 4, 1981 Docket No.
50-261 Mr. J. A. Jones Senior Executive Vice President Carolina Power and Light Company 336 Fayetteville Street Raleigh, North Carolina 27602
Dear Mr. Jones:
The NRC staff has been reviewing the subject of control rod guide thimble wear in pressurized water reactors.
Based on our review, we have concluded that this issue is resolved for the 15 x 15 fuel assemblies designed by Exxon for H. B. Robinson, Unit No. 2.
The propensity for guide thimble wear in Exxon reload fuel should be, to a first approximation, equivalent to that in Westinghouse fuel in the same plant.
Examinations of Exxon fuel that was discharged from your facility, as reported by Exxon letter dated February 25, 1980, revealed no through wall wear nor major differences in the wear from that wear which was meas ured on Westinghouse fuel that was discharged from Pt. Beach, Units Nos. 1 and 2.
The Exxon examinations were performed on 5 fuel assemblies that had been under control rod banks for one cycle of reactor operation. One assembly was from Cycle 4 and four assemblies were from Cycle 5 operation. Of the 100 guide thimble tubes examined by an eddy current testing (ECT) method, only 11 had detectable wear (i.e., wear greater than about 3 mils local wall thinning). The ECT measurements did not reveal the azimuthal dis tribution of the wear, but if the worst wear that was detected had been concentrated on one side of the guide thimble tube wall, it would have indicated that a minimum of 23% of the wall thickness remained.
We conclude that (a)-the degree of wear measured by Exxon is acceptable, (b) the degree of wear in the Exxon fuel is similar to that in Westinghouse fuel, which we have found acceptable, and (c) the issue of guide thimble wear in Exxon-fueled Westinghouse-NSSS plants has been adequately resolved.
Sipcerely 1even.Y' g~a, hief Operating Reactor Branch #1 Division of Lice'1 ing cc:
See next page
Mr. J. A. Jones Carolina Power and Light Company cc:
G. F. Trowbridge, Esquire Shaw, Pittman, Potts and Trowbridge 1800 M Street, N.W.
Washington, D. C. 20036 Hartsville Memorial Library Home and Fifth Avenues Hartsville, South Carolina 29550 U. S. Nuclear Regulatory Comission Resident Inspector's Office H. B. Robinson Steam Electric Plant Route 5, Box 266-1A Hartsville, South Carolina 29550 Michael C. Farrar, Chairman Atomic Safety and Licensing Appeal Board Panel U. S. Nuclear Regulatory Commission ashington, D. C. 20555 Richard S. Salzman Atomic Safety and Licensing Appeal Board Panel U. S. Nuclear Regulatory Commission Washingt.on, D. C.
20555 Dr. W. Reed Johnson Atomic Safety and Licensing Appeal Board Panel U. S. Nuclear Reculatory Commission Washington, D. C. 20555