ML20235T474
| ML20235T474 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 07/13/1987 |
| From: | Allen C COMMONWEALTH EDISON CO. |
| To: | Denton NRC, NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| 2214K, IEB-79-26, NUDOCS 8707220152 | |
| Download: ML20235T474 (2) | |
Text
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-/ m\\ Commonwedith Edison
'e' f..i. / One First Nation 1 Plaza, Chicago, Illinois 2 Address Reply to: Post Offic Box 767 i'\\_,/
Chicago, Illinois 60690 0767.
July 13, 1987 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555
Subject:
LaSalle County Station Unit 2 License condition (7) Id)
NRC Docket No. 50-374 Reference (a):
I.E.Bulletin 79-26 Rev.'sion 1, Boron Loss from BVR Contral Blades
Dear Mr. Denton:
Attached is Commoreealth Edison's (CECO) response to satisfy NPF-18, License condition (7) (d). Unit 2 Initial Critical for Cycle 2 was June 16, 1987.
If you have anv questions regarding this matter, please contact this office.
Very truly yours, C. M. Allen Nuclear Licensing Administrator es Attachment cc:
P. Shemanski NRC Resident Incpector - LSCS Region III Administrator M.C. Parker - IDNS
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Response to IE Bulletin 79-26 Revision 1, I
Boron Loss from BWR Control Blades (NPF-18, License Condition (7)(d))
Item 1.
In accordance with LTP-1600-29, Control Blade End-of-Life Projection, LaSalle tracks control blade exposure history on a monthly basis.
Exposure records are maintained and updated on four 3-foot segments for each control blade on a continuing basis.
Item 2.
For the current cycle, LaSalle does not have any control blades which exceed 34% boron depletion (all control blade segments are depleted less than 10%).
By using LTP-1600-29 to predict the depletion of each segment, any control blade having a segment which will exceed 34% boron depletion (1.962 snvt) in the next cycle can be discharged prior to beginning that cycle.
Item 3.
Prior to the initial startup for LaSalle 2 Cycle 2, a single rod subcriticality check (LTP-1600-30) was performed utilizing the analytically determined strongest rod.
In addition, during CRD testing each control blade was fully withdrawn and criticality was not achieved.
LTS-1100-14, Local Shutdown Margin Suberitical De%cnstration, was performed on 6-16-87 (prior to initial critical for Cycle 2) utilizing the strongest control rod, 54-43; 58-43 (Lymmetric rod to 02-43, the Fine Motion Control Rod Drive); and a roc diagonally adjacent to the strongest rod. With this three rod local shutdown margin demonstration, a shutdown margin of at least 1.372% WK/K was demonstrated, which is in excess of 1.232% WK/K (.38% WK/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 6-16-87.
The beginning of cycle shutdown margin was determined to be 2.81% WK/K for Unit 2.
A boron loss shutdown margin increment was not required for the Unit 2 Cycle 2 shutdown margin tests because all control blade segments
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are less than 34% depleted (see Item 2).
A boron loss increment for j
future cycles will not be necessary since the General Electric
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B C original equipment control blades will be discharged prior to j
4 exceeding 34% boron depletion, j
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