ML20069B805

Discusses 940105 Telcon W/Nrc Re Requested Issuance of Notice of Enforcement Discretion from TS 3.1.3.7 for LaSalle Station,Unit 1

ML20069B805
Person / Time
Site:	LaSalle
Issue date:	01/05/1994
From:	Benes G COMMONWEALTH EDISON CO.
To:	Martin J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML20069B791	List: ML20069B805
References
NUDOCS 9405310147
Download: ML20069B805 (7)

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IN Ccmm:nwrith Edison 6 ) LaSalle County Nuclear Statinn

. 2N)1 FL 21st Rd.

/ Marseilles, Illinois 61341

,, Telephone 815/357-676i January 5, 1994 r-de 7. B. Martin * ':

4 ,13nal Administrator 0 i Nuclear Regulatory Commission * '

+ 'n III j

801 Narrenville Road Lisle, Illinois 60532 -

Subject:

LaSalle County Station Unit 1 Request for Issuance of Notice of Enforcement Discretion to Technical Specificati.on 3.1.3.7 i NRC Docket Number 50-373

Dear Mr. Martin:

The purpose of this letter is to document the.results of a conference call between Commonwealth Edison Company (CECO) and the NRC staff on January 5, 1994, in which CECO requested issuance of a Notice of Enforcement Discretion (NOED) from Technical Specification 3.1.3.7, Action =

Statement, for LaSalle County Station Unit 1.

On January 4, 1994,4at 2307 (bST),laSa51e. Unit 1 entered Technical Specification 3.1. 3.7 Action Statement due to the inoperability of the. Control Rod Position Indication System (RPIS).

CECO requested that the 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> to be in H6t Shutdown be extended an additional 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />'in order to allow time to repair and test the RPIS. A Notice of Enforcement Discretion for an additional six hours (instead~of the 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> CECO requested) was. verbally approved by Region III at 1200 (CST) on January 5, 1994.

The basis of the request is provided in the Attachment and includes:

• The Technical Specification that will be violated;

• The circumstances surrounding the condition, including the need for prompt action;

• The safety basis for the request that enforcement discretion be exercised,

_ including an evaluatica of the safety significance and potential consequences of the proposed course of. action; 9405310147 930107 PDR ADOCK 05000,773 p POR

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Any proposed compensatory measure (s);

• The justification for the duratio'n of the '

reytest; '

The basis for the' conclusion that tha request will not have a potential adverse impact on the public health and safety, and that a significant safety hazard is not involved; and The basis [or the conclusion that the request will not involve, adverse consequences to the environment. ~ ., ..

At 1132 on January 5, 1994, repairs of the RPIS were completed. At 1340 on January 5, 1994, testing of the RPIS was completed and RPIS was declared operable upon completion of the documentation.

This request for Enforcement Discretion .ias been reviewed and approved by LaSalle On-Site Review Committee, in accordance with LaSalle Station procedures.

CECO sincerely appreciates the NRC staff's effort and participation in the review of this request. Please direct any questions or comments to Gary Benes, Nuclear Licensing Administrator, at (708) 663-7282.

Very Truly Yours, byf5ew Gary G. Benes .

'*1 clear Licensing Administrator '

Attachment cc: D. Hills, Resident Inspector - LaSalle A. T. Gody Jr., Project Manager - NRR B. Clayton, RIII Branch Chier NRC Document Control I

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6,TTACHMENT 1.

TECHNICAL SPECIFICATION OR LICENSING CONDITION THAT WILL BE VIOLATED At 2307 on January 4,1994, LaSalle County Station Unit i entered Technical l Specification 3.1.3.7. Action a, due to the inoperability of the Control Rod Position Indication System (RP!S). Since no direct control rod position indication was available in the Main  !

Control Room and could not be restored within one hour, action a 4 requires Unit 1 to be in ,

Hot Shutdown within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. Repairs may not be completed within the 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> '

provided to reach Hot Shutdown. l Therefore, Commonwealth Edison requests Enforcement Discretion from Technical Specrfication 3.1.3.7 for an additional 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> to be able to repair RPIS. l LaSalle County Station (LaSalle) Unit 2 RPIS is Operable.

2. CIRCUMSTANCES SURROUNDING THE SITUATION There were no power changes or control rod movements in progress at the time RPIS was lost. The failure of RPIS is not currently known, and the troubleshooting to determine the failed component (s) plus the repair time will exceed the time allowed to reach Hot Shutdown. 1 3.

EVALUATION OF SAFETY SIGNIFICANCE AND CONSEQUENCES Control Rod Position !Mication is provided by the Reactor Manual Control System.

The safety function of Control Rods is to provide the primary means for rapid reactivity control (reactor scram), for maintaining the reactor subcritical and for limiting the potential effects of reactivity insertion events caused by malfunctions of the Control Rod Drive (CRD) i System. The capahility to insert the control rods ensures the assumptions for scram reactivity in the DBA and transient analyses are not violated. The control rod scram function is not affected by the loss of RPIS. RPIS is used to determine control rod operability and for I controlling rod pattems. Currently movement of a control rod or rods without control room operator knowledge is not directly indicated in the Main Control Room due to the drift alarm also not being available. However, any significant control rod movement will cause a reactmty change and thus a power change. Any power changes can be detected tr/ other means: the APRMs are all Operable as well as indications of Feedwater flow, and Main Generattsr Output in MWe. i The withdrawn control rods were exercised per Surveillance Requirement 4.1.3.1.2 on the l

midnight shift 1/4/94. The last known control rod positions from the Control Room were I verified on the aftemoon shift on 1/4/94. The Control Rod positions were verified by ~

altemate means at approximately 0830,1/5/94. All control rc.:s are fully withdrawn except for five control rods, which are ful!y inserted. If a single control rod drifts, it can not pass the l

tip of any other rod due to the current rod positions. The Control Rods that are full in are

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high power rods, which will cause a power change if a drift occurs. These 5 full-in control _-

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rods are being electrically and hydraulically isolated.

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4. COMPENSATORY ACTIONS The following Compensatory Actions will be placed in effect:

1) Unit 1 power will not be changed during the time RPIS is inoperable to aid in the determination of any control rod drifts.

2) Control Rod positions are being verified once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> using a multimeter in the Aux Electric Equipment Room.

3) Core Thermal Pcwer and LPRM readings a ; being monfiored approximately every 15 minutes via the plant process computer.

4) The APRMs, Feedwater flow, and Generator MWe are being monitored continuously using a dedicated operator.

5) No scram functional testing (half-scrams) are either required or will be performed during the time RPIS is inoperable due to the inoperability of the drift alarm.

Control Room Operators have been directed to manually scram the reactor if any changes in monitored parameters indicate possible control rod drifts.

Once the problem has ceen identified and corrected, control rod movement (one notch) will be performed to verify the operability of RPIS in accordance with plant procedures.

5. JUSTIFICATION FOR THE DURATION OF THE REQUEST:

l The requested allowed outage time extension is 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. This time is requested to I complete the necessary repair and subsequent testing of the RPIS. These times are I referenced from 1100 CST on January 5,1994:

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Complete repairs to RPIS. (1 to 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />) l l .

Perform testing in accordance with LOS-AA-W1 to exercise all withdrawn l control rods to test each control rod's position indication. (Technical l Specification Surveillance Requirements 4.1.3.1.2 and,4.1.3.7.b and c. and l complete documentation of operability. (3 to 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />) l k:WaksaneWHed3.wph2 I Current Technical Spedfications requirements will necessitate a plant shutdown by I reactor manual scram at 1207 CST on January 5,1994. The only means of shutdown I currently available is by scram after power reduction using the Reactor Recirc system to l reduce core flow. The probability of an undetected control rod drift with the above I compensatosy actions is extremely small during extension of the allowed outage time by 6 I hours, or tha time required to repair RPIS, whichever occurs first. Granting of this requested l cforcement discretion is necessary to minimize the risk associated with scramming the l reactor from approximately 55% to 60% power, which places the plant in a transient I condition, causes the unit to undergo unnecessary thermal cycles on plant equipment and l any associated challenges to safety systems.

l l CECO believes that there is a high likelihood that RPIS will be restored to Operable prior to I the expiration of the requested increased allowed outage time. If RPIS is not restored to an 1 Operable condition by the end of time a!! owed by granting of this enforcement discretion, I the unit will be shutdown by reducing power and scramming the reactor prior to the i expiration of the enforcement discretion in accordance with Technical Specification 3.1.3.7.

I I The safety significance associated with the duration o0 Lis request is minimal. Multiple I indications of reactor power are being monitored for detection of control rod. drift. Any ,.

I indication of control rod drift will require a manual scram. Also, if multiple accumulator I alarms are received at the same time, the reactor will be manually scrammed.

6. EVAt.UATION OF SIGNIFICANT HAZARDS CONSIDERKrlON Commonwealth Edison has evaluated the propcsed request for Enforcement Discretion and determined that it does not represent a significant hazards consideration.

Based on the criteria for defining a significant hazards consideration established in 10 CFR 50.92, operation of LaSalle County Station Unit 1 in accordance with the proposed request will not: -

1) Involve a significant increase in the probability or consequences of an accident previousty evaluated because:

a. There is no affect on accident initiators so there is no change in probability of an accident. The probability of a failure of the control rods to shutdown the reactor by scram is not affected by the failure of RPIS. RPIS and the Reactor Manual Control System does not affect either the Reactor Protection System or the scram function of Control Rods,

b. The failure of RPIS does not affect the control rods ability to scram and shutdown the reactor. Therefore, the consequences of previousty evaluated accidents are not increased.

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2) Create the possibility of a new or different kind of accident from any accident previously evaluated because:

The Rod Position Indication System and the Reactor Manual Control System are totally separate from the control rod scram function and the Reactor Protection System. Control Rod Drop or Drifts that make significant i reactivity changes will be detected by means of continuous monitoring of  !

APRMs, Feedwater flow, and Main Generator MWe. Also, core thermal 1

power and LPRMs are being periodically monitored.

3) Involve a significant reduction in the margin of safety because:

The Rod Position Indication System and the Reactor Manual Control System are totally separate from the control rod scram function and the Reactor Protection System. Control Rod Drifts that make significant reactivity changes will be detected by means of continuous monitoring of APRMs, Feedwater flow, and Main Generator MWe. Also, core thermal power and LPRMc F4 being periodically monitored. LaSalle Unit 1 is currently greater than Srw; gower, with all but 5 centrol rods (the remaining 5 rods are Full In) fully wiemawn, so the consequences a control rod drift are minimal due to no intermediate positioned control rods. The ability to shutdown the reactoris not affected. The actual control rod positions will be determined in the Aux.-

Electric Equipment Room once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> while RPIS is inoperable.

Guidance has been provided in "Fina: Procedures and Standards on No Significant Hazards Considerations," Final Rule, 51 FR 7744, for the application of standards to license change requests for determination of the existance of significant hazards considerations.

This document provides examples of amendments which are and are not considered likely to involve significant hazards considerations. This request for enforcement discretion most closely fits the example of a change which may either result in some increase to the probacility or consequences of a previously analyzed accident or may reduce in some way a safety margin, but where the results of the change are clearty within all acceptable criteria with respect to the system or component specified in the applicable Standard Review Plan.

This request for enforcement discretion does not involve a significant relaxation of the criteria used to establish safety limits, a significant relaxation of the bases for the limiting safety system settings or a significant relaxation of the bases for the limiting conditions for operations. Therefore, based on the guidance provided in the Federal Register and the enteria established in 10 CFR 50.92(c), the proposed change does not constitute a significant hazards consideration.

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7. ENVIRONMENTAL ASSESSMENT LaSalle County Station has evaluated the proposed enf#.:ement discretion against the criteria for identification of licensing and regulatory actions requiring environmental assessment in accordance with 10 CFR 51.20. It has been determined that the proposed changes meet the criteria for a categorical exclusion as provided under 10 CFR 51.22(c)(9).

This conclusion has been determined because the changes requested do not pose significant hazards considerations or do not involve a significant increase in the amounts, 1- and no significant changes in the types, of any effluents that may be released off site.

Additionalty, this request does not involve a significant increase in individual or cumulative occupational radiation exposure.

8. APPROVAL BY ON SITE REVIEW

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l The request has been approved by LaSalle County Senior Station Management and On-Site Review (OSR) in accordance with Station procedures, l

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