NPL-98-0766, Application for Amends to Licenses DPR-24 & DPR-27,revising TS to Ensure 4 Kv Bus Undervoltage Input to Reactor Trip Is Controlled IAW Design & Licensing Basis for Facility

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Application for Amends to Licenses DPR-24 & DPR-27,revising TS to Ensure 4 Kv Bus Undervoltage Input to Reactor Trip Is Controlled IAW Design & Licensing Basis for Facility
ML20154G544
Person / Time
Site: Point Beach  NextEra Energy icon.png
Issue date: 10/07/1998
From: Reddemann M
WISCONSIN ELECTRIC POWER CO.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20154G550 List:
References
NPL-98-0766, NPL-98-766, NUDOCS 9810130223
Download: ML20154G544 (10)
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4 MARK E. REDOEMANN W EkW A WISCONSIN ENERGY COMPANY S"'V'**"*"'

Point Beach Nuclear Plant 6610 Nuclear Rd.

i Two Rivers, WI 54241 Phone 920 755-6527 l

NPL 98-0766 10 CFR 50.4 l 10 CFR 50.90 )

October 7,1998 - l l

Document Control Desk

.U.S. NUCLEAR REGULATORY COMMISSION

^ Mail Station PI-137 I l Washington,DC 20555 Ladies / Gentlemen:

DOCKETS 50-266 AND 50-301 TECHNICAL SPECIFICATIONS CHANGE REOUEST 207 LIMITING CONDITIONS FOR OPERATION UNDERVOLTAGE REACTOR TRIP POINT BEACH NUCLEAR PLANT. UNITS 1 AND 2 In accordance with the requirements of 10 CFR 50.4 and 10 CFR 50.90, Wisconsin Electric Power Company (Licensee), hereby requests amendments to Facility Operating Licenses DPR-24 and DPR-27 for Point Beach Nuclear Plant, Units 1 and 2, respectively. The purpose of the proposed amendments is to incorporate changes to the Technical Specifications to ensure the 4 kV bus undervoltage input to reactor trip is controlled in accordance with the design and licensing basis for the facility.

During a review of the Technical Specifications, a Wisconsin Electric (WE) engineer, identified that the Limiting Condition of Operation for the 4 kV undervoltage protection function, did not require placing an inoperable channel in trip, and allowed operation indefinitely in that condition.

j By not placing an inoperable channel in trip, a single failure within this function could prohibit a reactor trip. This trip is the primary protective function for the complete loss of flow analysis as documented in the PBNP Final Safety Analysis Report and therefore, is required to meet the single failure criteria specified in IEEE 279.

These amendments to the Technical Specifications will require placing an inoperable channel in trip, thus the Technical Specifications for this function will ensure that PBNP Units are operated in accordance with their design bases. /

One additional administrative change is requested which removes the footnote related to the definition of Rated Power in Technical Specifications 15.1.j. This footnote should have been L

deleted with the issuance of Amendments 173 and 177 for Point Beach Nuclear Plant Units 1 and 2, respectively. These amendments t.pproved operation of PBNP following replacement of the 9810130223 981007 26 I i

PDR ADOCK O p e

NPL 98-0766 l 10/07/98 i

Page 2 l

PBNP Unit 2 steam generators. The footnote supported operation with increased steam generator tube plugging levels being experienced in the Unit 2 steam generators prior to replacement. The

) power level restrictions contained in this footnote are no longer supported by the analyses performed for Amendments 173 and 177.

I It has been detemiined that the proposed amendments do not involve a significant hazards consideration, authorize a significant change in the types or total amounts of any effluent release,

or result in any significant increase in individual or cumulative occupational exposure.

l Therefore, the proposed amendments meet the requirements of 10 CFR 51.22(c)(9) and an environmental impact statement or negative declaration and environmental impact appraisal need not be prepared.

A description of changes, safety evaluation, determination of no significant hazards, and edited Technical Specification pages are attached.

l Please contact us if you have any questions or require additional information.

Sincerely, dfM Mark Reddemann Subscribed and sworn before me on Site Vice President this/M day of 22h4< v 1998.

Point Beach Nuclear Plant Jhg gfj,4 1 JG/dms Notarftublic, State of Wisconsin Attachments My commission expires W /4 200/

cc: NRC Regional Administrator NRC Resident Inspector Public Service Commission of Wisconsin i

i l

NPL 98-0766 Attachment 1 Page 1 6

DESCRIPTION AND BASIS FOR CHANGES TECHNICAL SPECIFICATION CHANGE REOUEST 207 LIMITING CONDITIONS FOR OPERATION UNDERVOLTAGE REACTOR TRIP POINT BEACH NUCLEAR PLANT. UNITS 1 AND 2 Introduction Wisconsin Electric Power Company, licensee for the Point Beach Nuclear Plant, Units 1 and 2, requests amendments to Facility Operating Licenses DPR-24 and DPR-27 to incorporate changes to the Technical Specifications. These changes are being made to accurately reflect the PBNP design and licensing basis.

The proposed changes remove a footnote related to the definition of Rated Power that is no longer supported by PBNP analyses and should have been removed by Amendment 173 and 177 for Units 1 and 2, respectively. Also proposed is the addition of a requirement to place an inoperable Undervoltage Reactor Trip channel in trip, thus ensuring this protective function continues to meet single-failure criteria during reactor operation in this condition.

Definition of Rated Power The following changes are proposed to Technical Specification 15.1.j:

j. Rated Power Rated Power is here defined as a steady state reactor core output of 1518.5 MWT.*-

The footnote indicated by

  • located at the bottom of Technical Specifications page 15.1-4 is deleted.

Basis for Chance This footnote was approved with Amendments 165 and 169 for PBNP Units 1 and 2, l respectively, on November 17,1995. The amendments supported operation of PBNP Unit 2 i at reduced reactor coolant system flows as a result ofincreased steam generator tube )

plugging levels. Subsequently, the Unit 2 steam generators were replaced and operation with l

the new steam generators approved by Amendments 173 and 177 for Units 1 and 2, respectively, on July 1,1997.

The analyses supporting the latter amendments were performed at a reactor coolant system  ;

total flow rate of 181,800 gpm based on an assumed measurement uncertainty of 2.1 percent l over thermal design flow (178,000 gpm) as reflected in Technical Specification 15.3.1.G. j

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NPL 98-0766 Attachment 1 Page 2 Therefore, this footnote is no longer applicable and should have been deleted with the approval of the July 1,1997 amendments. Thus, this change is administrative only.

Undervoltage Reactor Trip Technical Specifications Table 15.3.5-2, Instrument Conditions For Reactor Trip, contains the operability requirements and limiting conditions for operation (LCO) for reactor trip system instrumentation. Proposed changes to item 14.a of this table are as follows.

I 2 3 4 TOTAL NO. OF MINIMUM PERMISSIDLE OPERATOR ACTION IF CONDITIONS NO. OF CHANNELS OPERADLE BYPASS OF COLUMN 3 CANNOT BE MET NO2 FUNCTIONAL UNIT CIIANNELS TO TRIP CHANNELS CONDITIONS

14. 4 kV Bus (A01/A02)
a. Undervoltage (input 2/each 1/each 1/each ** Be in hot shutdown in 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> to reactor trip) bus bus bus The existing table footnote, designated **, is proposed to be made applicable to this line item. This footnote states:

If a channel is detemiined to be inoperable, resulting iri one less than the total number of channels being operable, power operation may continue if the following conditions are met:

1. The minimum number of operable channels is still satisfied.
2. The affected channel is placed in trip within I hour.

Basis for Chance As discussed in the PBNP Final Safety Analysis Report, Section 14.1.8, the undervoltage i reactor trip is the primary protective function credited in the complete loss of reactor coolant j flow analysis. Primary protective functions a.e designed to meet the criteria of proposed IEEE 279-1968 including protection against sirigle failures as referenced in FSAR

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Section 7.2. Thi:: function satisfies a "one out of two, taken twice" logic. That is, at least one channel on each bus must sense an undervoltage condition to initiate a reactor trip.

The present Technical Specification for this furetion allows an inoperable channel to exist indefinitely with no action required. If one channel on a bus is failed in the un-tripped condition and the remaining channel would fail to trip during an undervoltage condition, l reactor trip would be prevented. Thus, the single failure criteria ofIEEE 279 is not satisfied l for this primary protective function under the provisions of the existing Technical l Specification allowed condition.

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NPL 98-0766 Attachment 1-.

Page 3 Placing an inoperable channel in trip will ensure the protective function will be fulfilled assuming a single failure of an operable channel as long as both channels on at least one of the buses are operable; thus satisfying the design criteria defined in the FSAR.

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l. This proposed change is essentially identical to the provisions in NUREG 1431, Standard (

[ Technical Specifications, Westinghouse Reactors.  !

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NPL 98-0766 Attachment 2 Page1 t

SAFETY EVALUATION TECHNICAL SPECIFICATION CHANGE REOUEST 207 LIMITING CONDITIONS FOR OPERATION UNDERVOLTAGE REACTOR TRIP POINT BEACH NUCLEAR PLANT. UNITS 1 AND 2 Wisconsin Electric Power Company, licensee for the Point Beach Nuclear Plant, requests amendments to Facility Operating Licenses DPR-24 and DPR-27, to effect changes to the plant Technical Specifications. These changes are necessary to ensure the facility is operated in accordance with its design and licensing basis as approved by the Nuclear Regulatory Commission.

Technical Specifications 15.1.j definition of Rated Power, presently contains a footnote designated *. This footnote states:

For Unit 2: If the Reactor Coolant System raw measured total flow rate is

<174,000 gpm but 2169,500 gpm, Unit .2 shall be limited to s; 98% rated power.

This footnote was approved with Amendments 165 and 169 for PBNP Units 1 and 2, respectively, on November 17,1995. The amendments supported operation of PBNP Unit 2 at reduced reactor coolant system flows as a result ofincreased steam generator tube plugging levels. Subsequently, the Unit 2 steam generators were replaced and operation with the new steam generators approved by Amendments 173 and 177 for Units 1 and 2, respectively, on July 1,1997.

The analyses supporting the latter amendments were performed at a reactor coolant system total flow rate of 181,800 gpm based on an assumed measurement uncertainty of 2.1 percent over thermal design flow (178,000 gpm) as reflected in Technical Specification 15.3.1.G.

Therefore, this footnote is no longer applicable and no longer supported by the approved analyses. The footnote should have been deleted with the approval of the July 1,1997 amendments. As this proposed change is suppotted by previously reviewed and approved analyses, this change is administrative only, reflecting the present approved operation of the facility.

Technical Specifications Table 15.3.5-2, Instrument Conditions For Reactor Trip, contains the operability requirements and limiting conditions for operation (LCO) for reactor trip system instrumentation. Item 14.a provides the LCO for the undervoltage reactor trip protection function.

As discussed in the PBNP Final Safety Analysis Report (FSAR), Section 14.1.8, the undervoltage reactor trip is the primary protective function credited in the complete loss of

1 NPL 98-0766 Attachment 2 Page 2 reactor coolant flow analysis. FSA.R Section 7.2 stipulates that primary protective functions are designed to meet the criteria of proposed IEEE 279-1968 including protection against single failures.

4 kV buses A01 and A02 each supply one reactor coolant pump. An undervoltage on a bus will result in the loss of power to the associated reactor coolant pump. Loss of power to both buses will result in a complete loss of reactor coolant flow.

The undervoltage reactor trip protection function is made up of a "one out of two taken twice" channel logic. That is, there are two channels sensing undervoltage on each 4 kV bus, A01 and A02 (four channels total). One channel on each bus must sense an undervoltage to make up the trip logic. The trip setting for this function is specified in Technical Specification 15.2.3.1.B(6).

The present Technical Specification for this function allows an inoperable channel to exist on each bus indefinitely with no limit on reactor operation. If one channel on a bus is failed in the un-tripped condition and the remaining channel on that bus fails, an undervoltage on that bus would not be sensed. Since the logic would only "see" an undervoltage on the bus with  ;

the two operable channels, the trip logic would not be satisfied and reactor trip would be l prevented. Thus, the single failure criteria of proposed IEEE 279-1968 is not satisfied for this primary protective function under the provisions of the existing Technical Specifications.

Therefore, it is proposed that existing table note designated ** be made applicable to this line item. The ** will be added to the column 3," Minimum Operable Channels" requirement of 1/each bus. This new table note states:

"If a channel is determined to be inoperable, resulting in one less than the total number of channels being inoperable, power operation may continue if the following conditions are met:

1. The minimum number ofoperable channels is still satisfied.
2. The affected channel is placed in trip within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />."

With the logic for this function, placing one channel on a single bus in trip results in that half of the trip logic being satisfied. Therefore, the response ofone or both channels on the other bus to an undervoltage condition will result in a reactor trip. Since one operable channel can fail and the protective function still be satisfied with an inoperable channel in trip, this proposed criteria ensures single failure criteria required by proposed IEEE 279-1968 and l documented in the FSAR is met.

Placing inoperable channel on a single bus in trip will ensure the protective function will be fulfilled assuming a single failure in the remaining channels, thus satisfying the single failure

NPL 98-0766 Attachment 2 Page 3 design criteria defined in the FSAR. When failures occur 'vithin the function that will prevent the protective function assuming a single failure to occur, action is required to place the affected Unit in a hot shutdown condition. In this condition, the protective function is not required. If a complete loss of coolant flow were to occur shortly after rcaching hot shutdown conditions, natural circulation flow is capable of removing the required decay heat.

The Technical Specifications as modified will ensure that applicable safety limits are met for the complete loss of reactor coolant flow event as analyzed in the FSAR, ensuring PBNP is operated in accordance with its design and licensing basis.

This change is essentially identical to the provisions contained in the improved Standard Technical Specification for Westinghouse Reactors, NUREG 1431.

NPL 98-0766 1 Attachment 3 l

l Page1 l 1

NO SIGNIFICANT HAZARDS DETERMINATION TECHNICAL SPECIFICATION CH ANGE REOUEST 207 LIMITING CONDITIONS FOR OPERATION UNDERVOLTAGE REACTOR TRIP l

POINT BEACH NUCLEAR PLANT, UNITS 1 AND 2 l Wisconsin Electric Power Company, licensee for the Point Beach Nuclear Plant, requests amendments to Facility Operating Licenses DPR-24 and DPR-27 to incorporate changes to the Technical Specifications. The proposed changes correct an administrative discrepancy associated with previously approved amerdments related to the definition of Rated Power, and revise the Limiting Conditions for Operation for the undervoltage reactor trip function to ensure operation in accordance with approved analyses for a complete loss of reactor coolant flow event. l The proposed changes have been evaluated in accordance with the requirements of 10 CFR 50.91 against the standards in 10 CFR 50.92. We have determined that the operation of the Point Beach Nuclear Plant in accordance with the proposed amendments does not result in a significant hazards consideration. The evaluation against each of the criteria of 10 CFR 50.92 follows.

1. Operation of the Point Beach Nuclear Plant in accordance with the proposed amendments will not create a significant increase in the probability or consequences of an accident previously evaluated.

The changes proposed ensure the Point Beach Nuclear Plant continues to be operated in accordance with the design and licensing basis for the facility.

The first change removes a footnote qualifying the definition of Rated Power as applied to PBNP Unit 2. This restriction was eliminated with the replacement of Unit 2 steam generators as approved by Amendments 173 and 177, dated July 1,1997. The analyses for those amendments were performed based on the minimum flow requirements specified in Technical Specification 15.3.1.G.3. The note should have been deleted from the Technical Specifications at that time. Elimination of this note does not result in a change in the operation of PBNP from that analyzed and approved in Amendments 173 and 177. Therefore, this change is administrative and cannot result in an increase in probability or consequences of an accident previously evaluated.

The second change modifies the Limiting Condition For Operation for the undervoltage reactor trip protection function. This trip function is the primary protective function credited in the complete loss of flow event analysis in the Final Safety Analysis Report (FSAR) Section 14.1.8. As a primary protective function, this trip is required to be single failure proof as stipulated in proposed IEEE 279-1968 documented in FSAR

NPL 98-0766 Attaclunent 3 Page 2 4

Section 7.2. This change ensures that this protective feature is maintained in a condition where single failure considerations are satisfied. When single failure criteria cannot be met, appropriate action is stipulated to shutdown the unit placing it in a condition where the protective function is no longer required. Therefore, this change ensures PBNP is operated in accordance with its design and licensing basis and cannot result in an increase in the probability or consequences of an accident previously evaluated.

2. Operation of the Point Beach Nuclear Plant in accordance with the proposed amendments will not create the possibility of a new or different kind of accident from any accident previously evaluated.

The changes proposed by this request remove a footnote qualifying the defmition of rated power as it applies to PBNP Unit 2 operation, and modify the LCO related to the undervoltage reactor trip protective function to ensure this function is maintained as required by the PBNP design and licensing basis. These changes are in agreement with approved analyses. These changes do not introduce any new accident initiators or alter the response of the PBNP Units to previously analyzed accidents. Therefore, operation of PBNP in accordance with the proposed changes cannot result in a new or different kind of accident from any accident previously evaluated.

3. Operation of the Point Beach Nuclear Plant in accordance with the proposed amendments does not create a significant reduction in a margin of safety.

Operation of the PBNP in accordance with the proposed amendments is within the bounds of approved design and licensing basis of the facility. The design and licensing basis establish appropriate margins of safety. Since operation of the PBNP remains within the approved design and licensing basis of the facility, a reduction in a margin of safety cannot result.

Conclusion Operation of the Point Beach Nuclear Plant in accordance with the proposed amendments does not result in a significant increase in the probability or consequence of any accident  ;

previously evaluated; does not result in a new or different type of accident than any accident previously evaluated; and, cannot result in a decrease in a margin of safety. Therefore, 4 operation of the Point Beach Nuclear Plant in accordance with the proposed amendments 1 does not result in significant hazards consideration.

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