ML20211A863
| ML20211A863 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 10/06/1986 |
| From: | Allen C COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| 2214K, IEB-79-26, NUDOCS 8610170047 | |
| Download: ML20211A863 (2) | |
Text
- _ _ _
) Commonwealth Edison
- 72 West Adams Street, Chicago, Illinois Address Reply to
- Post OffTce Box 767 Chicago, lltinois 60690 0767 October 6, 1986 Mr. Harold R. Denton, Director office of Nuclear Reectoi Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555
Subject:
LaSalle County Station Unit 1 License condition 2.C.(12)
NRC Docket No. 50-373 Reference (a):
I.E.Bulletin 79-26 Revision 1, Boron Loss from BWR Control Blades
Dear Mr. Denton:
Attached is Commonwealth Edison's (CECO) response to satisfy NPF-11, License Co.'.11 tion 2.C.(13).
Unit 1 Initial Critical for Cycle 2 was September 17, 1986.
If you have any questions regarding this matter, please contact this office.
One signed original and forty (40) copies of this transmittal is provided for your use.
Very truly yours, C. M. Allen Nuclear Licensing Administrator im Attachment cc:
Dr. A. Bournia - NRR NRC Resident Inspector - LSCS j
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.m 8610170047 861006
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2214K PDR ADOCK 05000373 (l
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ATTAC15ENT Response to IE Bulletin 79-26 Revision 1, Boron Loss from BWR Control Blades (NPF-ll, License condition 2.C.(13))
Item 1.
LaSalle is tracking control rod blade exposure history on a monthly basis in accordance with LTP-1600-29, Control Blade End-of-Life Projection. Exposure records are maintained on 3-foot segments of each blade (4 segments per blade) on a continuing basis.
Item 2.
Presently, LaSalle does not have any centrol blades which exceed l
34% boron depletion (all blade segments are less than 10%
depleted). A control blade will be discharged prior to exceeding l
34% boron depletion (1.962 snvt) for any 3-foot segment in accordance with LTP-1600-29.
Item 3.
Prior to the initial startup for LaSalle 1 Cycle 2, a single rod subcriticality check (LTP-1600-30) was performed utilizing the analytically determined strongest rod. In addition, each control blade was individually fully withdrawn to perform CRD testing and criticality was not achieved.
A local subcritical shutdown margin test (LTS-1100-14) was performed on 9-17-86 (prior to the initial critical for Cycle 2) utilizing the strongest control rod and a diagonally adjacent control rod. A shutdown margin of 1.259% K/K was demonstrated, which is in excess of the 0.741% K/K (.38% K/K + R) required by Technical Specifications for Cycle 2.
A beginning of cycle shutdown margin (LTS-1100-1) was also determined from the initial critical on 9-17-86.
The beginning of cycle shutdown margin was determined to be 2.78% K/K for Unit 1.
A boron loss shutdown margin increment was not required for the Unit 1 Cycle 2 shutdown margin tests because all control blade segments are less than 34% depleted (see Item 2).
A boron loss increment for future cycles will not be necessary since the General Electric B 4C original equipment control blades will be discharged prior to exceeding 34% boron depletion.
2214K
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