ML20151X462

Application for Amends to Licenses NPF-11 & NPF-18,providing Addl Requirements for Monitoring Core Performance.Fee Paid

ML20151X462
Person / Time
Site:	LaSalle
Issue date:	04/26/1988
From:	Allen C COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
Shared Package
ML20151X467	List: ML20151X462 ML20151X471
References
NUDOCS 8805040159
Download: ML20151X462 (6)

Text

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s ., .

. N Ccmmonwhith Edison

/ One Fest Nateal Plaza, CNeago, Illues g7 Address Repiy to: Post Offce Box 767 CNcago, filinos 60690 0767 I

April 26, 1988 U.S. Nuclear Regulatory Commission

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ATTENTION: Document Control Desk Washington, DC 20555

Subject:

LaSalle County Station Units 1 and 2 Proposed Amendment to Technical specifications for Facility Operating

Licenses NPF-ll and NPF Core Performance Monitoring NRC Docket Nos. 50-373 and 50-374 i

References (a): Federal Register Volume 51 No. 44 7 dated March 6, 1986.

(b): Letter dated January 19, 1988 transmitting Reload Licensing Package for LaSalle Unit 1 i Cycle 3.

Dear Sir:

Pursuant to 10 CFR 50.90, commonwealth Edison proposes to amend Facility Operating Licenses NPP-11 and NPF-18. This amendment is being submitted for your staff's review and approval and is in accordance with Reference (a).

This amendment provides additional require'nents for monitoring : ore performance and other actions to be taken by the reactor operator in the high power / low flow region of the power to flow map. These changes are a result of NRC concerns due to a recent occurrence at LaSalle Unit 2. These changes are unique to IsSalle and are an interim solution to NRC concerns until power to flow stability issues arising from the event at LaSalle are resolved.

Attachment A provides an introduction and discussion. Attachment B provides copies of the changes to be made to the Facility Operating Licenses.

Commonwealth Edison has reviewed this document and finds that no significant hazards consideration exists. This review is documented in Attachment C. [

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ADOCK 05000373 LI DCD

i USNRC April 26, 1988 Commonwealth Edison is notifying the State of Illinois of our request for this amendment by transmitting a copy of this letter and its attachments to the designated State official.

In accordance with 10 CFR 1~10, a fee remittance in the amount of

$150.00 is enclosed.

The effective date of this amendment should be the date of issuance.

If you have any additional questions regarding this matter, please contact this office.

Very truly yours, C. M. Allen Nuclear Licensing Administrator la

Enclosure:

$150.00 Fee Attachments cc: P. Shemanski - NRR Regional Administrator - RIII NRC Resident Inspector - LSCS M. C. Parker - IDNS SUBSCRIBED AND o to befor/JoetJs, J' ay of IJ flu J r , 1988 r_ l_ . Al%

' Notary Public 4511K

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l-P ATTAQOENT A I  !

TBCHNICAl, SPECIFICATION CHANGE RRQUEST l LASALLE COUNTY STATION UNITS 1 AND 2 l l

BACEGROUND e f

-The Lasalle Unit 1 Cycle 3 (LIC3) Reload Analysis was transmitted to l

_ the NRC in Reference (b). The LIC3 Reload Core was calculated to have a *

-stability decay ratio of 0.75 which is less than the NRC criteria of 0.80 for

-stability monitoring technical specifications. Based on that caculation, no stability: monitoring technical specifications changes were included in .

. Reference (b). Subsequently, an event occurred at LaSalle Unit 2 which caused neutron flux osc11ations during natural circulation conditions, since the i

.Lasalle;2 Cycle-2-(L2C2) Core stability decay 2;etio was calculated to be 0.60, the event served to question the stability margin calculation for LIC3.. Due i to this event and the continuing investigation regarding decay ration calcula- i tions, both units at Lasalle will be treated as having "high decay ratio" i cores. -Technical specification changes for stability monitoring and actions to be taken by an operator if oscillations are observed are provided as an extra margin of safety until the investigation is completed.

1 DISCUSSION i This submittal adds a new specification for recirculation system I thermal hydraulic stability. It also clarifies the specification on the  !

reactor recirculation system and revises the bases to reflect these changes, cThe new specification, as well as the clarifications, follow the guidance of i Gencral Electric SIL-380 and similar approaches in other standardized i Technical specifications. These specifications are similar for Units 1 and  !

2.

l specification 3/4.4.1.5 consolidates the requirements for thermal c hydraulic stability. The important aspects of this specification are: I t

(1) Definition of the power / flow region in roman numerals. This i reduces the confusion generated by use of the de3criptive titles  !

alone, i.e., "surveillance region - restricted zone", "surveillance  !

, region - allowable zone *, and "allowable region", which appear in the existing specification.

(2) The actions are contained in a region oriented format. With the old recirculation 1079 specification doubling as a stability specificathi, the relativa importorce of the power / flow map regions was obscured behind the rect'a pump status criteria. The new region oriented R wat is more straightfo m rd and concentrates operator atsee r,to act!on requo ad to asa te thermal hydraulic stability is . *.

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(3) Elimination of operation within an Action statement. The new stability specification contains a provision in the LCO to allow operation inside the stability surveillance region. Previously, operation within the surveillance region (Region II) would allow indefinite periods of operation within the action statements.

(4) Immediate actions within Region I to observe APRM and LPRM noise level and exit the Region; a) When operating with no recirculation pumps on, the specification requires reducing power with control rods to a fixed power level which is conservatively below the 80% flow control line at any achievable flow. With one or two recirc pumps on, flow may be increased to exit Region I with a recirc pump that is already operating.

b) APRM and LPRM noise levels are to be observed during the reduction in core power by control rod insertion. The specification requires that the operator be cognizant of neutron flux noise present in the indicators available to him during the normal course of control rod insertions and to immediately exit the Region. If these observations of the APRMs and LPRMs result in indications of flux oscillations of greater than 10% peak-to-peak, a manual scram is required which is achieved by the operator placing the reactor mode switch into the SHUTDOWN position. This noise level observation does not require a formally documented surveillance since the surveillance requirement applies to Region II only and the operators attention must be concentrated on exiting Region I as soon as possible.

, (5) The wording of the surveillance requirement for Region II in the stability monitoring Technical Specification is rearranged such that the wording clearly specifies that the surveillance must be initiated within 15 minutes and completed within the next 30 minutes. This clarification is intended to assist in preventing mistakes and interpretation of the time requirements of the surveillance.

(6) Specification 3.4.1.1 (Reactor Recirculation) is also cross-referenced in this specification to assist the operator in identifying other applicable specifications.

(7) In order to facilitate rapid recognition of instability, a fixed i

noise criteria was added in addition to the existing criteria of 3 times the baseline noise level. This fixed criteria of 10% meter indication (peak-to peak noise) has been justified by General Electric and is a logical and easily remembered criteria for the operator. The APRM and LPRM noise meters cannot be accurately read to within less than 2 to 3 meter units. Therefore baseline noise indication of less than 3 meter units would not be meaningful for stability monitoring.

The Reactor Recirculation Loops Specification (3/4.4.1.1) has also been revised to cross reference the Thermal Hydraulic Stability Technical specification (3/4.1.5). This is to make the specifications "user friendly" and minimize the possibility that a required action in another specification might be forgotten.

The bases have been revised to provide guidance that in Region I the operators top priority is to observe neutron flux indication and exit the Region promptly. If neutron flux oscillations are observed the operator is to scram the unit by placing the reactor mode switch to the SHUTDOWN position.

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TECHNICAL SPECIFICATION CHANGE R @ EST l LASALLE COUNTY STATION UNITS 1 AND 2 ,

PROPOSED CHANGES TO APPENDIX A CHANGED PAGES:

NPF-11 NPF-18 VI (Revised) VI (Revised)

XIX (Revised) XIX (Revised) 3/4 4-1 (Replaced) 3/4 4-1 (Replaced) 3/4 4-la (Replaced) 3/4 4-2 (Replaced) '

3/4 4-lb (Deleted) 3/4 4-2a (Deleted) 3/4 4-4a (New) 3/4 4-5a (New) 3/4 4-4b (New) 3/4 4-5b (New) 3/4 4-4c (New) 3/4 4-5c (New)

B 3/4 4-1 (Revised) B 3/4 4-1 (Revised) e I

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