ML20116K766

Application for Amend to License NPF-3,changing TS 3/4.3.1, RPS Instrumentation & 3/4.3.2.3, Anticipatory RTS Instrumentation to Implement NRC-approved BAW-10167

ML20116K766
Person / Time
Site:	Davis Besse
Issue date:	11/13/1992
From:	Myers T, Shelton D CENTERIOR ENERGY
To:
Shared Package
ML20116K762	List: ML20116K760 ML20116K766 ML20116K770
References
2081, NUDOCS 9211170365
Download: ML20116K766 (12)

Text

_ _

,- Docket Number 50-346

.' License Number NPF-3 Serial Number 2081 Fuclosure Page 1 APPLICATION FOR AMENDMENT TO FACILITY OPE 7ATING LICENSE NUhBER NPF-3 DAVIS-BESSE NUCLEAR POWER STATION UNIT NUMBER 1 Attached are requested changes to the Davis-Besse Nuclear Power Station, Unit Number 1 Facility Operating License Number NPF-3 Appendix A, Technical Specifications. Also included is the Safety Assessment and Significant Hazarda Consideration.

The proposed changes (submitted under cover letter Serial Number 2081) concern:

Technical Specification 3/4.3.1, Reactor Protection System Instrumentation.

Technical Specification 3/4.3.2.3, Anticipatory Reactor Trip System Instrumentation.

For: D. C. Shelton, Vice President - Nuclear By:  ! ); .

T. J. b'r , Direr. tor - Technical Services

/

Sworn and subscribed before me this 13th Jay of November, 1992 YJ1/l/h] ~ ll4 l-State of Ohio Notary Publig,~EVavNL DRESS f,: N ot M.sraTEOFOHIO "lCuu:a w 4 9 y, y I

9211170365 921113 PDR ADOCK 05000346 P PDR

, Docket-Number 50-346 License Number NPF-3 Serial Number 2081 Enclosure Page 2 The following information is provided to support issuance of the requested changes to the Davis-Besse Nucitar Pover Station, Unit Number 1 Operating License Number NPF-3, Appendix A. Technical Specifications, Technical Specifications 3/4.3.1 and 3/4.3.2.3.

A. Time required to implement: These changes are to be implemented within 90 days after issuance of the License Amendment by the NRC.

B. Reason for change (License Amendment Request Number 90-0002):

These changes are required to implement increased RPS and ARTS channel fur.ctional test surveillance test intervals and RPS allowed-out-of-service times as permitted by the NRC-approved Babcock and Vilcox (BLV) Topical Report, BAV-10167, " Justification for Increasing the Reactor Trip System On-Line Test Intervals," and supplements. These changes vill result in better utilization of technician resources and reduce the potential for spurious reactor trips during testing and when one instrument channel is inoperable.

The other proposed changes are required to prescribe appropriate actions to be taken if two RPS channels become inoperable; make surveillance requirements for the source and intermediate range instrumentation commensurate with the functions performed; and, correct a typographical error.

C. Safety Assessment and Significant Hazards Consideration: See Attachment.

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Docket Number 50-346 l License Mumber NPF 3 Serial Number 2081 Attachment Page 1 SAFETY ASSESSMENT AND SIGNIFICANT HAZARDS CONSIDERATION FOR LICENSE AMENDMENT REQUEST NUMBER 90-0002 TITLE Increase of Reactor Protection System (RPS) and Anticipatory Reactor Trip System (ARTS) Instrumentation Channel Functional Test Surveillance Interval and Allov Plant Operation to Continue Indefinitely with One Inopetable RPS Instrument Channel in Bypass.

DESCRIPTION The main purpose of the proposed changes is to implement the NRC approved Babcock and Vilcox (B&V) Topical Report, BAV-10167,

" Justification for Increasing the Reactor Trip System On-Line Test Intervals," and its supplements for the Davis-Besse Nuclear Power Station (DBNPS) Unit Number 1. The proposed changes revise the DBNPS Operating License, NPF-3, Appendix A, Technical Specifications (TS),

3/4.3.1, " Reactor Protection System Instrumentation," and 3/4.3.2.3,

" Anticipatory Reactor Trip System Instrumentation," to:

1. Increase the channe! functional test surveillance test interval for most RPS and ARTS instrument channels from monthly to semi-annually, on a staggered test basis.

2. Allow plant operation to continue indefinitely with one RPS instrument chant el placed in bypass.

3. Add an action statement to permit continued operation for 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> with two of four RPS channels inoperable, one in trip and the other in bypass.

4. Eliminate channel functional test surveillance requircmants for source and intermediate range neutron flux instrumentation.

5. Decrease the channel calibration surveillance test interval for the High Flux / Number of Reactor Coolant Pumps On trip from once every eighteen months to quarterly, to be consistent with the quarterly channel calibration surveillance interval for the High Flux and Flux -oFlux - Flov Instrumentation.

6. Correct a typographical error in the numbering of page 3/4 3-30c.

Change 1) noted above consists of changes to TS Table 4.3-1, Reactor Protection System Instrumentation Surveillance Requirements, and TS Table 4.3-17, Anticipatory Reactor Trip System Instrumentation Surveillance Requirements. Specifically, in Table 4.3-1, the channel functional test surveillance test interval for functional units 3, 5, 6, 7, 9, and 14 is changed from "M" (monthly) to "SA(9)" (semi-annually with Note 9 applying). Note 9 is added to Table 4.3-1 to indicate the semi-annual channel functional tests are to be performed on a staggered test basis, consistent with the assumptions of BAV-10167. For

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• Docket Number 50-3/5

, License Number NPF-3 Setial Number 2081 Attachment Page 2 functional units 2 and 4, the channel functional test interval is changed from "M" to "N.A." (not applicable). The channel functional test is indicated as no longer applicable since these functional units are calibrated quarterly. The channel calibration includes the channel functional test by TS definition 1.9. Note 9 is also added to the quatterly calibration requirements of functional units 2 and 4 and to the monthly functional testing tequirements of functional units 12 and 13 to ensure that these functional units are tested on a staggered test basis as assumed in BAV-10167. In Table 4.3-17, the channel functional test interval for functional units 1 and 2 is revised from "M" to "SA(c)" (remi-annually with Note (c) applying). Note (c) is added to Table 4.3-17 to indicate the semi-annual channel functional tests are to be performed on a staggered test basis, consistent with the assumptions of BAV-101.67.

Change 2) above consists of changes to Table 3.3-1, Reactor Protection System Instrementation, Actions 2 and 3. Action 2a is revised to require an inoperable channel be placed in either the bypassed or tripped condition within one hour. Action 2b is deleted. It is no longet neceesary since Action 2a nov permits an inoperable channel to be bypas;ed indefinitely and surveillance tests can be performed v tSoot resulting in a reactor trip while in this condition.

i Action 2c i e, unenanged but editorially becomes Action 2b. Similarly, Action 3 is tevised to require an inoperable channel be placed in eithsr the bypassed or tripped condition within one hour. Action 3b is deleted.

It is no longer necessary since Action 3 now permits an inoperable channel to be bypassed indefinitely and surveillance tests can be performed without resulting in a reactor trip while in this condition.

Change 3) above consists of the addition of a new Action 10 to Table 3.3-1 which is applicable to functional units 2 through 9. Action 10 permits continued operation for 48 houts with two of four channels inoperable, one in trip and the other in bypass. Currently, the TS are unduly restrictive for the condition where tvo channels are inoperable.

If this situation vere to occur, TS 3.0.3 vould immediately Le invoked.

The proposed Action 10 is adopted from the Restructured Standard Technical Specifications (RSTS) for B&W Plants (NUREG-1430, Section 3.3.1).

Change 4) above consists of changes to Table 4.3-1. Specifically the channel functional test interval for functional unit 10, intermediate range neutron flux and rate insttumentation, is revised from "S/U(5)(1)" (prior to reactor startup with Notes (1) and (5) applying) to "N.A.", and the channel functional test interval for functional unit 11, source range neutron flux and rate instrumentation, is revised from "M and S/U(1)(5)" (monthly while in Modes 2 through 5 and prior to reactor startup vith Notes (1) and (5) applying) to "N.A.". Although these surveillance requirements technically are required only prior to startup and monthly for the source range instruments while the plant is shutdown, the channel functional test is performed monthly while the plant is operating in Mode 1 to assure that the surveillance tequirements are always current in the event the plant experiences a reactor trip or unplanned shutdown (Reference DBNPS Licensee Event

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Docket Number _50-346 1 ,' License Number NPF-3 Serial Number 2081 Attachment Page 3

-Report (LER)91-002). Toledo Edison considered increasing the monthly-curveillance interval for the source range instrumentation to  ;

semi-annually under the umbrella of BAV-10167 to alleviate this burden. I However, it was noted that the B&V RSTS eliminate the channel functional tests for source and intermediate-range instrumentation en the basis that they perform only a monitoring function except for I control rod withdrawal inhibit, which is only required during low power l physics testing. For instrumentation that performs a monitoring l function, the RSTS consider 18 month interval channel calibrations and )

channel checks each shift to be the approprit .e surveillance  ;

requirements. As in the RSTS, the control rod withdraval-inhibit function is verified under the existing DBNPS Special Test Exception l 3.10.2, Physics Tests, by surveillance requirement 4.10.2.2.

Change 5) above consists of a change to Table 4.3-1 for functional unit 8, High Flux /Nriber of Reactor Coolant Pumps On. Specifically, the channel calibration .nterval is decreased from "R" (18 months) to "O(6,9)" (quarterly with Notes 6 and 9 applying). Note 6 exempts the neutron detectors from the channel calibration. Note 9 requires testing to be carried out on a staggered test basis consistent with the assumptions of BAV-10167. The High Lux / Number of Reactor Coolant Pumps On trip uses input from functional units 2 and 4, High Flux and Flux _-aFlux - Flov, respectively, which are calibrate.' quarterly. Since -

functional units 2_and 4 are required to be calibrated _more frequently than functional unit 8, the potential exists for adjustments made during the calibration of functional units 2 and 4 to adversely affect the calibration of functional unit 8. DBNPS LER 92-006 documents such occurrences. It is therefore appropriate for functional units 2, 4, and 8 to be calibrated at the same frequency to reduce the future potential for such occurrences. The functional unit 8 channel functional test interval is also revised from "M" to "N.A.". As part of Change 1) above, the channel functional test interval for functional unit 8 vould have been revised to SA(9) as justified by BAV-10167.

However, because the proposed quarterly channel calibration includes the channel functional test, a remi-annual channel functional test is not applicable.

Change 6) above requests that the page number "3/4 30c" be changed to "3/4 3-30c" as an editorial correction.

SYSTEMS, COMPONENTS AND ACTIVITIES AFFECTED The proposed changes affect surveillance test intervals and allowed out of service times for RPS and ARTS instrument channels. There are no hardware modifications involved.

e. g i. Docket Number 50-346 3 ', License Number NPF-3 Serial Number 2081 Attachment Page 4 SAFETY FUNCTION OF THE AFFECTED SYSTEMS. COMPONENTS AND ACTIVITIES As dcscribed in the DENPS Updated Safety Analysis Report-(USAR),_

Section 7.2, the RPS monitors various plant parameters (reactor coolant system pressure, temperature, flow, neutron flux, number of reactor coolant pumps on, and containment pressure) to detect undesired-conditions and trip the reactor to protect the integrity of the fuel cladding and prevent reactor coolant system overpressure. The ARTS, described in USAR Section 7.4.1.4, monitors plant conditions (turbine trip, trip of both main feed pumps, steam and feedvater rupture control system) which are indicative of reduced secondary heat removal capability and initiates a reactor trip in advance of the RPS.

Although the RPS reactor coolant system high pressure trip would ultimately trip the reactor during loss of secondary heat removal events, the ARTS initiates a reactor trip in advance of the RPS vhen-conditions indicate reduced secondary heat removal capability. This action results in a lower peak RCS pressure during such events and reduces the potential for challenges to the pilot operated relief valve (PORV).

An RPS instrument channel can be taken out of service during plant operation and placed in either bypass or trip. RPS instrument channels

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are equipped with channel bypasses. The channel bypasses permit one channel of a functional unit to be bypassed to allow testing and maintenance of the instrument strings without increasing susceptibility to spurious trips. Susceptibility to spurious trips increases when a channel is placed in trip because RPS then operates as a one-out-of-three system, requiring only one of the remaining channels to trip to result in a reactor trip. Vith one channel bypaased, RPS operates as a two-out-of-three system, requiring the trip of a minimum of two of the remaining three channels to result in a reactor trip.

The channel bypasses are key operated. The keys are under the administrative control of the shift supervisor. Hard-vired interlocks prevent more than one RPS channel from being bypassed at a time.

EFFECTS ON SAFETY Changes 1) and 2)

The proposed increases in the channel functional test surveillance interval from one-to six months for RPS and ARTS' instrument channels, and the proposed change-to allow plant operation to continue indefinitely with an RP instrument channel in bypass have been shown to be acceptable by the tfRC-approved Babcock and Vilcox (B&V) Topical-Report BAV-10167, " Justification for Increasing the Reactor Trip System On-Line Test Intervals" and supplements._ BAV-10167 was submitted to BAV-10167 justifies increases to the RPS and the NRC in June, 1986.

ARTS channel ~ functional test intervals from monthly to semi-annually on a staggered test-basis and justifies plant _ operation for_an indefinite-period with a single inoperable channel placed in bypass. On March 14, 1988 Supplement 1 to BAV-10167 was submitted in response to NRC questions. The NRC Safety Evaluation Report (SER)'related to BAV-10167; and-Supplement 1'vas issued on December 5, 1988.

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' '. License Number NPF-3 Serial Number 2081 Attachment Page 5 The SER concluded that the proposed semi-annual channel functional test intervals for RPS instrument channels were acceptable provided tnat-licensees confirm that the drift occurring over the proposed surveillance test interval vould not cause the setpoint values to exceed those assumed in the safety analysis and specified in the TS.

However, the original SER did not accept continued operation for an indefinite period with one channel in bypass and proposed to limit the allovable out of service time (A0T) to 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />. In November, 1989, the B&W ovners Group submitted BAV-10167, Supplement 2 which provided additional justification for an indefinite A0T. On July 8, 1992, the NRC Staff issued a supplemental SER to BAV-10167 vhich approved an indefinite A0T for one inoperable channel in bypass.

PAV-10167 used reliability block diagrams (RBD) to model RPS and ARTS.

Separate models vere constructed for the Oconee and Davis-Besse classes of plants. Separate models were required for the two classes of plants because the reactor trip breakers (RTB) trip only the safety control rod groups in the Oconee class of plants and the electronic trip (silicon controlled rectifier-SCR) is required to trip the regulating control rod groups. In the Davis-Besse class of plants, the RTBs and the electronic trip each trip all regulating and safety control rod groups. Because of this design difference, the Davis-Besce RPS is inherently more reliable and its unavailability (probability of failure on demand) is less sensitive to changes in surveillance intervals.-

BAV-10167 used the PACRAT computer code to evaluate the time dependent RPS and ARTS unavailability for one, four, and six month channel functional test intervals using the RPS and ARTS reliability block diagram models. The models included the effects of changes in system configuration during testing and maintenance, and the effects of staggered testing. .The effects of human errors and common mode failures associated with testing and maintenance vere also assessed.

The use of component failure data from operating experience was emphasized. Where directly applicable operating data was not available, standard generic data sources were used in BAV-10167. The RPS unavailability was calculated for one, four, and six month RPS instrument string channel functional tect intervals. All cases vere run with no restrictions on the allovable outage time (A0T) for one channel in bypass. That is one channel could be bypassed for the entire mean-time-to-repair (HTTR) distributed-around a mean of 108 hours0.00125 days <br />0.03 hours <br />1.785714e-4 weeks <br />4.1094e-5 months <br />. To further justify an indefinite A0T, BAV-10167, Supplement 2 explicitly modeled the RPS as a four channel system with one channel continuously bypassed. Uncertainty analysis was performed.to determine upper bound unavailabilities. For the Davis-Besse class of pla RPS and ARTS best estimate unavailability ranged from 1.1 X for 10 gts, the the current one month test interval to 9.0 X 10~9 for the proposed six-month test interval. BAV-10167 also estimated the overall effects of the changes on " risk" in terms of core damage frequency using the Oconee probabilistic risk assessment (PRA). Two competing effects on risk resulting from an increased test interval are a slight increase in risk due to greater RPS unavailability due to failures remaining undiscovered for a longer period and a decrease in risk due to fever spurious trips during testing. BAV-10167 estimated there vould be a net i

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'. -License Number NPP-3 Serial Number 2081 Attachment Page 6 reduction in core damage frequency vith the increased testing interval. l This effect is less for the DBNPS due to changes in performance of surveillance tests which reduce the likelihood of spurious trips during testing. However, the overall conclusion that the extension of the channel functional test interval and A0T has minimal adverse impact, if any, on safety remains valid.

As part of the NRC review of BAV-10167 and supplements, the NRC staff contracted the Idaho National Engineering Laboratory (INEL) to independently verify the conclusions of BAV-10167. INEL constructed and quantified a fault tree model of the RPS and ARTS to assess the effects of changes to surveillance intervals and A0Ts, and to test the 1 validity of assumptions made in BAV-10167. On the basis of the INEL review of BAV-10167, the NRC concluded that the proposed surveillance test intervals and A0Ts do not contribute an unacceptable increase to overall risk.

As required by the NRC SER related to BAV-10167, Toledo Edison has reviewed as-found and as-left (drift) data for the offected instrument strings over the period from January, 1988 through July 31, 1992.

(Instrument drift is defined as the portion between the upper leave-alone zone and the allovable value.) As result of this review, field setpoints for three functional units require adjustment, and acceptance criteria tolerances need to be tightened for six other functional units to ensure that RPS and ARTS vill operate conservatively relative to TS/ Safety Analysis setpoints with the longer channel functional test surveillance interval. Toledo Edison vill make these changes prior to utilizing the increased channel' functional test surveillance interval.

BAV-10167 assumed monthly functional tests for the reactor trip modules (RTM), reactor trip breakers, and electronic (SCR) trip.-In June, 1986 when BAV-10167 was submitted, the SCR trip vas not included in the DBNPS TS. The SCR trip was added to the DBNPS TS by Amendment Number 108 dated March 2, 1988. By letter dated March 27, 1987 (Serial Number 1312), Toledo Edison requested Amendment Number 108 in response to NRC Generic Letter 85-10, Technical Specifications for Generic Letter 83-28, Items 4.3 and 4.4, dated May 23, 1985 (Log Number 1756).

Generic Letter 85-10 recommended an 18 month. interval channel

{ functional tests for the SCR trip for the Davis-Besse class of plants.

l This surveillance interval was incorporated in the DBNPS TS for the SCR l trip. The 18 nonth interval SCR channel functional' test at the DBNPS l Individually verifles the operation of each SCR.

The monthly testing assumption for the SCR trip in BAV-10167 was based l on the-fact that the SCR. trip is exercised-monthly as part of'the reactor trip breaker functional test. The SCR' trip functions by the opening of relay contacts In the control rod drive system (CRDS) programmer lamp circuits. This removes the gating-signals from the.

SCRs. The relays are the only electromechanical component involved in-the SCR trip. The opening of the contacts is verified by the illumination of the control room programmer lamp fault light as part of the monthly RTM channel functional test. However, the control room

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'f License Number NpF-3 LSerial Number 2081.

Attachment-Page 7 prograaner lamp fault light vill illuminate if any of the contacts for any control. rod groups programmer opens. The monthly RTB functional-test procedure vill be revised to require individual verification of all programmer lamp: fault indicators at the CRDS group power supply cablocts.ptior to utilizing the increased channel functional intervals .

proposed by this license amendment request. ~This action vill verify n the electromechanical portion of the SCR trip on a monthly basis and-is j consistent with the degree:of monthly functional-testing of the SCR' trip assumed by BAV-10167.

With the changes to the RTB functional test procedure, adjustments'to field .=etpoints and test acceptance criteria noted above, Toledo Edison concludes that the changes proposed by BAV-10167 and approved by the NRC are applicable to the DBNPS and safe to implement.

Change 3)

A new Action 10 is added to Table 3.3-1 which is applicable to functional units 2 through 9. Action 10 permits continued operation for 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> with two of four channels inoperable (one in trip and the other in bypass). Currently, the TS are inadequate for-the condition where two channels are inoperable. If this situation vere to occur, TS 3.0.3 vould be invoked. TS 3.0.3 requires that a plant shutdown be initiated within one hour. 'As noted in NRC SER for BAV-10167, one hour -

is too short a time interval in which to initiate a.ny reasonable repair action. The proposed Action 10 would permit a reasonable time period to -

restore one inoperable channel to operable status and avoid an otherwise unwarranted plant shutdown. The need for-a-reasonable repair time is recognized in the Restructured Technical Specifications for_B&V-Plants, from which the proposed Action 10 was adopted. In the-condition allowed by Action 10, the plant would remain protected for postulated transients and nccidents with the RPS operating as a one-out-of-two trip system. It is expected that Action 10 would-be used infrequently.

Change 4)

The channel functional test interval for functienal unit 10, intermediate range neutron flux and rate instrumentation, is revised from "S/U(5)(1)" (prior to reactor startup with Notes (1) and (5) applying) to "N.A.", and the channel functional test interval for_

functional unit 11, source range neutron flux and. rate instrumentation,-

is revised from "M and S/U(1)(5)" (monthly while in Modes 2 through 5 and prior to reactor startup with Notes (1) and (5) app]ying) to "N.A.". Although these_ surveillance requirements _ technically are, required only prior to startup, and monthly for-the source range instruments while the plant is shutdown, the channel functional test is-t performed monthly even.during normal power operation to assure that.the surveillance requirements are always current in the event the plant is experiences a reactor trip or unplanned shutdown. Toledo Edison notes that the B&V RSTS eliminate the channel functional tests for source and intermediate range instrumentation on the basis that they perform only a monitoring function except for control rod withdrawal inhibit which-

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Docket Number 50-346

(* . License Number NPF-3 Serial Number 2081 Attachment Page 8 is only required during low power physics testing. For-instrumentation that perform'. a monitoring. function, the RSTS consider 18 month interval cht 01 calibrations and channel checks each shift to be the .

appropriate .;veillance requirements. As in the RSTS, the control rod withdraval inhibit function is verified by surveillance requirement 4.10.2.2 when Special Test Exception 3.10.2, Physics Tests, is invoked.

Toledo Edison considers that the proposed surveillance requirements'are commensurate with the function performed by the source and intermediate range neutron flux instrumentation. Accordingly, the revised surveillance requirements have no adverse impact on safety.

Change 5)

The channel calibiation interval for Table 4.3-1, functional unit 8, Iligh Flux / Number of Reactor Coolant Pumps On, is-decreased from "R" (18 months) to "0(6,9)" (quarterly with Note 6 and 9 applying). Note 6 exempts the neutron detectors from the channel calibration. Note 9 requires the surveillance to be performed on a staggered test basis.

The liigh Flux / Number of Reactor Coolant Pumps On trip uses input from functional unit 2, High Flux, and functional unit 4, Flux -AFlux -

Flow, which are calibrated quarterly. Since functional units:2 and 4~ '

are required to be calibrated more frequently than functional-unit 8, the potential exists for adjustments made during the calibration of functional units 2 and 4 to adversely affect the calibration of ,

functional unit 8. Therefore, it is appropriate for functional units 2, 4, and 8 to be calitrated at the same frequency. Since this proposed change reduces the potential for functional unit 8 becoming mis-calibrated, this change vill not have an adverse impact on safety.

Change 6)

Corrects a typographical-error in the numbering of page 3/4 3-30c and has no impact on. safety.

SIGNIFICANT HAZARDS CONSIDERATION The Nuclear Regulatory Comniission has provided standards in 10CFR50.92(c) for determining whether a significant-hazard exists due to a proposed amendment to an Operating License for a facility.- A proposed amendment involves no significant hazarus un. sideration if operation of the facility in accordance with the-proposed changes vould: (1) Not involve a significant increase in the probability or consequences of an accident previously evaluated;.(2) Not create the possibility of a=new or different kind of. accident from any accident previously evaluated; or (3) Not involve a significant reduction in a margin of safety. Toledo Edison has revieved the proposed changes and

--- . Docket Number 50-346 6-1 '+ '$ License Number NPF-3 Serial Number 2081 Attachment Page 9 determined that a significant hazards consideration does not exist because operation of the Davis-Besse Nuclear Power Station Unit 1 in accordance with these changes vould:

la) Not involve a significant increase in the probability of an accident previously evaluated because the proposed changes do not involve design modifications or changes in plant operation which adversely affect the probability of the initiation of previously

evaluated accidents. The Reactor Protection System (RPS) and Anticipatory Reactor Trip System (ARTS) primarily function to limit fuel damage thereby mitigating the consequences of accidents and transients. However, spurious trips initiate plant transients.

The proposed change to permit plant operation'to continue indefinitely with an inoperable RPS instrument channel in bypass instead of tripped, reduces the susceptibility of the RPS to spurious reactor trips, thereby reducing their probability of occurrence. The proposed increase in the RPS and ASTS channel functional test inter"al reduces the number of opportunities for the occurrence of spurious reactor trips during testing. The risk (probability and consequences) impacts of the proposed changes to the surveillance test intervals and allovable out of service times (A0Ts) have previously been evaluated by the NRC-approved Babcock and Vilcox (B&W) Topical Report, BAV-10167, " Justification for Increasing the Reactor Trip System On-Line Test Intervals," and its supplements. The NRC review concluded that the proposed surveillance test intervals and A0Ts do not contribute an unacceptable increase to overall risk. The proposed decrease in the channel calibration interval for the RPS High Flux / Number of Reactor Coolant Pumps On trip makes the calibration interval consistent with the RPS High Flux and Flux -6 Flux - Flow trips and does not affect the probability of an accident.

Ib) Not involve a significant increase in the consequences of an accident previously-evaluated because the proposed changes in RPS and ARTS channel functional test intervals and A0Ts continue to ensure high reliability of the RPS/ ARTS in limiting fuel damage and, therefore, the consequenc s of previously evaluated accidents. The risk (probability and consequences) impacts of the proposed changes to the surveillance test intervals and A0Ts have-previously been evaluated by the NRC-approved Babcock and Vilcox (B&V) Topical Report, BAV-10167, " Justification for Increasing the Reactor Trip System On-Line Test Intervals," and its supplements.

The NRC review concluded that the proposed surveillance test intervals and A0Ts do not make an unacceptable contribution to overall risk. The proposed decrease in the channel calibration

!nterval for the RPS High Flux / Number of Reactor Coolant Pumps On tcip makes the calibration interval consistent with the RPS High Flux and Flux -aFlux - Flow trips and continues to ensure high reliabili t y of this RPS trip in performing its intended function.

Therefore, the consequences of previously evaluated accidents are unaffected by this change.

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'. . License Number NPF-3 Serial Number 2081 Attachment Page 10 2a) Not create the possibility of a new kind of accident from any accident previously evaluated because there are no design modifications or hardware changes proposed. Furthermore, there are no new equipment failure modes or mechanisms introduced by the proposed changes.

2b) Not create the possibility of a dif ferent kind of accider; from any accident previously evaluated because there are no design modifications or hardware changes proposed. Furthermore, there are no offferent failure modes or mechaaisms introduced by the proposed changes.

3) Not involve a significant reduction in a margin of safety since the revised Technical Specifications surveillance intervals and allowed out of service times vill continue to ensure high reliability of RPS and ARTS in performing their intended functions.

CONCLUSION On the basis of the above, Toledo Edison has determined that the License Amendment Request does not involve a significant hazards consideration. As this License Amendment Request concerns a propo.=ed change to the Technical Specifications that must be reviewed by the Nuclear Regulatory Commission, this License Amendment Request does not constitute an unreviewed safety question.

ATTACHMENT Attached are the proposed marked-up changes to the Operating License.