ML19340E500
| ML19340E500 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 12/24/1980 |
| From: | Daltroff S PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| IEB-79-26, NUDOCS 8101140744 | |
| Download: ML19340E500 (2) | |
Text
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PHILADELPHIA ELECTRIC COMPANY M
2301 M ARKET STREET P.O. BOX 8699 h
PHILADELPHI A. PA.19101 C
SHIELDS L DALTROFF
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VICE PRESIDENT ELECTRIC PR, DUCTION T:9
- ~3 December 24, 1980 m
o Re: Docket No. 50-278 IE Bulletin 79-26 Mr. Boyce H.
Grier, Director Office of Inspection & Enforcement Region I United States Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406
Dear Mr. Grier:
This letter serves to supplement our response of December 17, 1979, to IE Bulletin 79-26 concerning B-10 loss from BWR control blades.
Item 3 of IE Bulletin 79-26 requested that Shutdown Margin (SDM) tests be conducted by including a plant specific increment in the Technical Specifications for SDM requirements that takes the potential loss of boron from the control rods into consideration.
Our response of December 17, 1979, to this item l
indicated that no blades exceeded 34% B-10 depletion at Peach Bottom Unit 3's recent refueling outage and no blade was predicted to exceed 34% during Unit 3's current operating cycle.
I Therefore, it was not necessary ut. that time to include any additional SDM adder to account for potential boron loss during the SDM demonstration test conducted during Unit 3's startup testing.
Control blade B-10 depletion has been continually l
monitored and it is apparent that certain blades are depleting i
l M
810114 O Q
~._ A Mr. Boyce H. Crior Page 2 faster than had been expected.
Our projections now indicate that 8 of the 185 control blades will exceed 34% B-10 depletion prior to the next Unit 3 refueling outage in March, 1981.
These blades, however, will not exceed 42% B-10 depletion and the maximum expected B-10 depletion is expected to be approximately 37%.
In accordance with IE Bulletin 79-26, we have determined a SDM adder in order that we may demonstrate that the Technical Specification requirements for SDM are satisfied during the remainder of cycle 4 with the 8 blades exceeding 34%.
The SDM adder was determined to be 0.1% AK/K which raises the Technical Specification requirement for SDM from 0.38%
4kK/K to 0.48% A K/K.
Since Unit 3 demonstrated a SDM of 1.6%
dsK/K during startup testing, the Technical Specification requirements are met with considerable margin during cycle 4 with the 8 control blades exceeding 34% B-10 depletion.
In addition, arrangements are being made to replace Unit 3's control blades exceeding 34% with new unirradiated control blades during the March, 1981 refueling outage.
If you require additional information, please contact us.
Very truly yours,
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U.S.
Nuclear Regulatory Commission Office of Inspection & Enforcement j
Division of Reactor Operations Inspection l
Washington, DC 20535 1
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