ML20138D330
| ML20138D330 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 10/11/1985 |
| From: | Massin H COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20138D336 | List: |
| References | |
| 0766K, 766K, NUDOCS 8510230238 | |
| Download: ML20138D330 (4) | |
Text
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/^'N Commonwealth Edison
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) One First Nationit Ptua. Chicigo. Ilhnois I
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" Addr:ss R ply to: Post Offica Box 767
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/ Chicago, Illinois 60690 i
October 11, 1985 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555
Subject:
LaSalle County Station Units 1 and 2 Proposed Amendments to Technical Specification for Facility Operating License PPF-ll and NPF-18 Source Range Monitor Operability NRC Docket Nos. 50-373 and 50-374
Reference:
G.E. Letter Rep: 85-099, R. E. Parr to J. L. Anderson "LaSalle Core Loading Procedures", dated May 28, 1985.
Dear Mr. Denton:
Pursuant to 10 CFR 50.59, Commonwealth Edis]n proposes to amend Appendix A, Technical Specification, to Facility Doerating License tPF-11 and NPF-18. This e.mendment change is being submitteJ for your staff's review and approval.
This proposed amendment revises the Technical Specifications to allow the count rate on the Source Range Monitor _($R'4) channels to go below the requireo counts per second where there are four or less fuel assemblies in a quadrant and they are positioned adjacent to the SRM in that quadrant.
The startup sources will be removed during the first refueling outage and therefore the SRM's.will not be operable, in order to allow refueling operations at the end of the outages, without this requested change to the
' technical specifications. Refueling of Unit 1 is currently scheduled to begin in February,1986.
It is also expected that adoption of the proposed technical specification change will minimize the need for use of " dunking detectors" during removal of the last few fuel asserrblies at subsequent outages..This is desirable in that the use of dunking detectors increases the risk of dropping loose objects into the vessel.
Attachment A provides background and discussion. The proposed change is enclosed in Attachment B.
The attached change has received both On-Site and Off-Site review and approval. We have reviewed this amendment request and find that no significant hazards consideration exists. Our review is documented in Attachment C.
Commonwealth Edison is notifying the State of Illinois of our
[,g request for this amendment by transmitting a copy of this letter and its
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attachments to the designated State Official.
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8510230238 851011 20 PDR ADOCK 05000373-I M
P PDR
pgypr H. R. Denton October 11, 1985 In accordance with the requirements of 10 CFR 50.170, a fee remittance in the amount of $150.00 is enclosed.
Please direct any questions you may have concerning this matter to this office.
Three (3) ~ signed originals and thirty-seven (37) copies of this transmittal and its attachments are provided for your use.
Very truly yours, hMVc d H. L.
assin Nuclear Licensing Administrator 1m Attachments A: Background and Discussion B: Technical Specification Change to rPF-ll and tPF-18 C: Evaluation of Significant Hazards Consideration D: Referenced Letter: REP 85-099 dated May 28, 1985 cc: Region III Inspector - LSCS A. Bournia - NRR M. Parker - State of Ill SUBSCRIEED AND SWORN to before me this day of
, 1985 Notary Public 0766K
V ATTACHMENT A TECHNICAL SPECIFICATION CHANGE REQUEST LASALLE COUNTY STATION UNITS 1 ano 2
SUBJECT:
LaSalle County Station Units 1 and 2 Source Range Monitor Operability BACKGROUND LaSalle's current Technical Specification (3/4.9.2) require that a Source Range Monitor (SRM) channel count rate of 0.7 cps (provided signal-to-noise ratio is y 2, otherwise, 3 cps) be maintained prior to and during core alterations for that channel to be declared operable. This count rate maybe monitored by the SRM detector, or by a special movable detector (dunker),
connected to the normal SRM circuitry.
The Technical Specifications also require that during core alterations, the detector (SRM or dunker) of an operable SRM channel is located in the core quadrant where core alterations are being performed and another is located in an adjacent cuadrant.
The first requirement assures, that whenever criticality is possible, neutron flux is being monitored so that an inadvertent approach to criticality cannot be achieved. The second requirement assures that there is acequate monitoring in any quadrant in which core alterations e m being made.
During refuel periods when the entire core is to be removed, it is unlikely that, without sources installed, a sufficient SRM channel count rate (0.7 cps) will be able to be demonstrated. Therefore, LaSalle is submitting a Technical Specification amendment which would allow the loading of up to four fuel assemblies around each SRM with no minimun channel count rate requirements.
DISCUSSION CECO requested General Electric (GE) to evaluate the proposed Technical Specification amendment. GE responded in the referenced letter (Attachment D) stating that a two-by-two square array of fuel assemblies loaded in the LaSalle reactors would have a reactivity of keff<,0.95 under the following conditions.
1.
A minimum of 12 inches (two fuel cells) exist between the two-by-two array ano any surrounding assemblies; 2.
They are at their maximum reactivity exposure; and 3.
They are uncontrolled Although assurance exists that keff <0.95 with up to four arbitrary fuel assenolles loaded around the SRMs, the possibility exists that the reactor will not meet the required Technical Specification shutdown
. margin (3/4.1.1) with the core loaded with four arbitrary assemblies around the SRMs. CECO has previously addressed this issue and has developed criteria which maintains the shudown margin requirements should the four fuel assemblies loaded around the SRMs be contrary to the final core loading pattern.
Based upon the GE evaluation and the CECO guidelines concerning shutdown margin, CECO concludes that inadvertent criticality is precluded.
for the loading of up to four assemblies around each SRM and that no SRM channel operability requirements need to be established with four or fewer assemblies loaded arouno the SRMs in each core quadrant.
The applicability section of Technical Specification 3.9.2 has been changed to allow the loading of four fuel assemblies around on SRM with no SRM channel operability requirements.
The instrumentation bases for refueling operations has also been revised by the addition of the words "whenever reactor criticality is possible", to clarify when the operability of the SRM channels is required.
Markea up copies of the appropriate Technical Specifications are enclosed ( Attachment B).
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