ML20090M799

Application for Amends to Licenses DPR-42 & DPR-60,revising TSs to Reflect Mods Being Performed as Part of Station Blackout/Electrical Safeguards Upgrade Project

ML20090M799
Person / Time
Site:	Prairie Island
Issue date:	03/20/1992
From:	Parker T NORTHERN STATES POWER CO.
To:
Shared Package
ML20090M798	List: ML20090M795 ML20090M799 ML20090M802
References
NUDOCS 9203250300
Download: ML20090M799 (38)

Text

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l UNITED STATES NUCLEAR REGULATORY COMMIS* ON NORTHERN STATES POWER COMPANY PRAIRIE IS1AND NUCLEAR GENEPATING PLANT DOCKET No. 50-282 50-306 REQUEST FOR AMENDMENT TO OPERATING LICENSES DPR 42 & DPR-60 LICENSE AMENDMENT REQUEST DATED March 20, 1992 _

Northern States Power Company, a Minnesota corporation, requests authorization for changes to-Appendix A of the Prairie Island Operating License as shown on the attachments labeled Exhibits A, B, and C. Exhibit A describes the proposed changes, describes the reasons for the changes, and contains a significant hazards evaluation, Exhibits B and C are copies of the Prairie Island Technical Specifications incorporating the proposed changes.

This letter contains no restricted or other defense information, NORTHERN STA'TES 10W 'R COMP.iNY

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By R (d

. omas MI Parker Manager Nuclear Support Services On this y of A.A -- @.{b.efore me a notary public in and for said County, personally appe'ared Thomas M Parker, Manager Nuclear Support Services, and being ff.rst duly sworn acknowledged that he is authorized to execute this document on behalf of Northern States Power Coropany, that he knows the contents thereof, and that co the best of his knowledge, information, and be-lief the state: rents made in it are true and that it is not interposed for delay.

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o' Exhibit A l Prairie Island Nuclear Generating Plant License Amendment Request Dated March 20, 1992 Evaluation of Proposed Changes to the Technical Specifications, Appendix A, of Operating Licenses DPR 42 6 DPR 60 Pursuant to 10 CFR Part 50, Sections 50.59 and 50.90, the holders of Operating Licenses DPR-42 and DPR 60 hereby propose the following changes to Appendix A.

Technical Specifications:

BACKGRQUND Prairie Island Nuclear. Generating Plant, Units 1 and 2, currently operate with euxiliary electrical systems employing two emergency diesel generators (D1 and D2) which are shared-between the two units. Under what is referred to as the Station-Blackout / Electrical Safeguards Upgrade Project (SB0/ESU Project),

Northern; States Power Company (NSP) is installing two new emergency diesel generators.(D5 and D6) and associated equipment at the Prairie Island Nuclear Generat.ng Plant. The two currently installed emergency diesel ganerators i

will_ be dedicated to _ Unit 1 'and certain common equipment while the two new emergency diesel generators will be dedicated to Unit 2 and certain common equipment. Thennew-auxiliary electrical systems configuration at Prairie

-_ Island along with related SB0/ESU Project improvements and upgrades will significantly improve overall plant safety, These plant changes are described in detail in the SB0/ESU Project Design.

-Report (Reference 1) submitted to NRC on November 27, 1990 and updated by

- Revision 1 (Reference 2) submitted on December 23, 1991, In those submittals, we coimnitted= to provide the necessary License Amendment Request.

Although detailed information is provided in the Design Report, a summary of the' scope of SB0/ESU Project changes is presented here.

Sco'oe and Descrintion cf ModificatioD1 1, The SB0/ESU-Project modifications consist of the following major >

-activities:

(1)- D5/D6 Emergency Diesel-Generator addition including _ the addition of-ai.xiliary support systems;-

(2) Now D5/D6 Diesel Generator Building addition;.

(3) Electrical Safeguards modificctions including new 4kV and 480V

-twitchgear' additions;

'(4) Plant interface connections to equipment within the existing structures; and

_(5) Upgrade of #121 Vertical Motor-Driven Cooling Water Pump for p safeguards use.

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Dhibit A Page 2 of 37

The scope of each activity is described in more detail below:

n DS/D6 Diesel Generator Addition The two new diesel generators (DS/D6) will be added to the Prairie Island Nuclear Generating Plant. These diesel generators will provide emergency-AC power to the Unit 2 safeguards buses and will be provided with connection capability to serve as alternate AC power sources for Unit 1 in

-the event of a station blackout on Unit 1. The-two existing emergency diesel generators (D1/D2) will provide emergency AC power to the Unit 1 safeguards buses and will be provided with connection capability to serve as alternato AC power sources for Unit 2 in the event of a station 1 blackout on Unit 2.

The two new diecel_ generators will each be provided with new cooling water ,

(radiator cooled), lube oil, fuel storage and transfer, ventilation and

starting air systems. These auxiliary systems are all located in the new DS/D6= Building. .The Unit 2 diesel fuel oil storage tanks will be

j. installed in underground vaults adjacent to the new building.

!- D5/D6 Diese1' Generator juildipg Addition- '

A new Seismic Category I DS/D6 Diesel Generator Building has been '

constructed to house .the two new diesel generators and auxiliary systems, including the Unit 2 safeguards buses. The building is located adjacent to the west end of the Auxiliary Building and the south side of the Turbine Building. _ The new building is a free standing structure with no structural connection to the' existing plant. .

Electrical Safeguards Upr.rnde The upgraded-safeguards. auxiliary power system includes new 4kV and 480V

buses for each Unit 2 safeguards train. One new 4kV bus per train (two-total) and two new 480V buses per train (four total) will be located in the new D5/D6 Building. _The undervoltage protection scheme for the new 4kVLbuses will meet Branch. Technical Position PSB-1. Two new qualified solid state programmable logic controller based loe.i sequencer _ systems will be' installed for Unit 2,

The existing Unit 14kV buses will be extended for additional capacity.

The existing Unit l'480V buses will be replaced by two new 480V buses per safeguards train (four total). Replacement of the Unit.1 430 V safeguards buse.s is scheduled for _ a later Unit 1 outage and will be the subject of a separate License Amendment- Request. The undervoltage protection scheme for the extended 4kV buses will meet Branch Technical Position PSB-1. Two new qualified solid state programmable logic controller-based load sequencer systems will be-installed for Unit-1.

The 480V safeguards buses in Unit 2 will be provided with automatic voltage regulation. Similar voltage regulation fcr Juit 1 480V safeguards -

buses will be provided_when the Unit 1 480V buses are replaced. -

o Eahibit A Page 3 of 37 Manual bus ties will be provided between the 4kV buses of the same train for the two units (e.g., between Unit 1 Train A and Unit 2 Train A) to provide an alternate AC power source during a station blackout event.

The 4kV safeguards buses in both units will be provided with direct connections to an "R" source transformer and to a Cooling Tower source trensforaer. This configuration will provide two immediate access independent offsite sources (i.e., a preferred and an alternate offsite source) to each 4kV safeguards bus.

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Cable connections between the new D5/D6 Building and the existing plant will bo installed under the plant interface scope. Cables will he routed through new and existing raceways. All cable runs in the existing plant will meet the requirements of the Prairie Island USAR as a minimum.

Il pr rade of a121 CooQng L'nter Pumn The existing vertical motor-driven cooling water pump wil1 be upgraded to safeguards classification under this modification. Power connection capability will be provided to both trains of Unit 2 4kV buses through a new 4kV Bus 27 which will be capable of manual alignment to either one or the otber train. The cables to n121 cooling water pump will be routed separately from either of the existing separation trains. The pump will receive an automatic start signal upon initiation of Safety Injection logic in either train of either unit. If both diesel-driven safeguards cooling water punps come up to speed, #121 cooling water pump will trip; otherwise it will continue to run.

The design of the upgraded auxiliary power systems also meets the requirements -

of the Station Blackout Rule, 10 CFR Part 50, Section 50.61, by providing alternate AC power supply to the blacked-out unit through use of an operating emergency diesel generator on the non-blackout unit. Conformance with 10 CFR Part 50, Section 50 63, is the subject of a separate NSP submittal (Reierence 3). The NRC responded to NSP's station blackout submittal in a Safety Evaluation Report (SER) dated September 18, 1990 (Reference 4). In the SER cover letter, the NRC staff stated:

The Technical Specifications (TSs) for SB0 should be consistent with the Interim Commission Policy Statement. The staf f has taken the position that TSs are required for SB0 equipment. However the question of how specification for the SB0 equipment will be applied, is currently being considered generically under the technical specification improvement program and remains an open itea at this time.

In the interim you are expected to prepare and maintain adequate procedures to reflect the appropriate testing and surveillance requirements to ensure the operability of tne SB0 equipment.

i Exhibit A Page 4 of 37 Therefore, Technical Specifications on the alternate AC power bus ties are not included in this submittal but will be included in a later submittal, if necessary.

The related Technical Specifications changes justified by the attached Safety Evaluation and Determination of Significant llazards Considerations are consistent with the design presented in the Design Report (References 1 and 2) as supplemented by our responses to NRC's requests for additional information (References 5, 6, 7, 8, 9). A safety evaluation has been performed including an analysis to assure that no single failure concerns have been introduced by the proposed changes.

The proposed Technical Specification changes have been categorized as either:

(1) Auxiliary Electrical Systems changes, or (2) Cooling Water System changes.

REFERENCES:

(1) Letter from Thomas M Parker, Northern States Power Company to U S Nuclear >

Regulatory Commission dated November 27, 1990 titled: " Design Report for the Station Blackout / Electrical Safeguards Upgrade Project" (2) Letter from Thomas M Parker, Northern States Power Company to U S Nuclear Regulatory Commission dated December 23, 1991 titled: " Design Report for the Station Blackout / Electrical Saf(guards Upgrade Project, Revision 1 (TAC Nos. 68588 and 68589)"

(3) Letter from David Musolf, Northern States Power Company to Director, Nuclear Peactor Regulation, U S NRC dated April 13, 1989 titled: " Loss of All Alternating Current Power Information Required by 10 CFR Part 50, Section 50.63(c)(1)"

(4) letter from Dominic C. Dilanni, Project Manager, Nuclear Reactor Regulation, U S NRC to T M Parker, Northern States Power Company dated September 18, 1990 titled: " Safety Evaluation of the Prairie Island Nuclear Generating Plant Unit Nos. 1 and 2; Station Blackout Rule 10 CFR 50.63 (TAC Nos. 68588 and 68589)"

(5) Letter from Thomas M Parker, Northern States Power Company to U S Nuclear Regulatory Commission dated March 20, 1991 titled: " Reply to Questions on Design Report for the Station Blackout / Electrical Safeguards Upgrade Proj ect (TAC Nos. 68588 and 68589)"

(6) Letter from Thomas M Parker, Northern States Power Company to U S Nuclear Regulatory Commission dated April 16, 1991 titled: " Reply to Questions on Design Report for the Station Blackout / Electrical Safeguards Upgrade Proj ec t (TAC Nos. 68588 and 68569)"

(7) Letter from Thomas M Parker, Northern States Power Company to U S Nuclear Regulatory Commission dated July 10, 1991 titled: " Reply to Questions on

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. Design Report for the Station Blackout / Electrical Safeguards Upgrade Project--(TAC Nos. 68588 and 68589)"

-(8)-Lotter from Thomas M Parker, Northern States Power cocapany to U S Nuclear  ;

Regulatory Commission dated October 24, 1991 titled: " Supplemental '

Information on Programmable Logic Controllers for the Station

- Blackout / Electrical Safeguards Upgrade Project ~ (TAC Nos. 68588 and 68589)"

(9) Letter from Thomas M Parker, Northern States Power Company to U S Nuclear Regulatory Commission dated January 8,1992 titled " Reply to Questions on Design Report for the Station Blackout / Electrical Safeguards Upgrade Project (TAC' Nos. M80659/80660)"

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Dhibit A Page 6 of 37 PROPOSED TECHNIfALSHCIFICATION CRANGES

1. AntUary Electrical Systru

a. Technical Specifications 3.7 and Tables TS.3.5-1 6 TS.3.5-5 Technical Specifications Baggs 3.5 and 3. 7 Erorored Changes Emergency Diesel Generatora Revise specifications 3.7.A. 3.7.B and specification basis 3.7 to __

reflect the new configuration for:

(1) addition of two new emergency diesel generators; and (2) the' Unit 1/ Unit 2 emergency diesel generator arrangement.

Revise specification 3.7.A.5 and specification basis 3.7 to reflect the new Unit 2 minimum diesel fuel oil supply. The proposed change specifies a minimun fue) oil volume of 75,000 gallors be maintained for emergency diesel pencrators D5 and D6 in the Unit 2 interconnected dienel fuel oil storage tanks.

Revise specification 3.7.A.5 and specification basin 3.7 to clarify that a fuel supply of 51,000 dallons be maintained for emergency diesel generators 31 and D2 in the Unit 1 interconnected diesel fuel oil storage tanks. In addition, clarify that a total fuel supply of 70,00G gallons be maintained for D1 and D2 diesel generators and the diesel-driven cooling water pumps in the Unit 1 interconnected diesel fuel oil storage tanks, Electrical Safeguards Upgrades-Revise specifications 3.7.A.1 and 3.7.B.1, 3.7.B.2, 3.7.B.3, 3.7.B.4 and 3.7.B.5 to clarify that the two separate. paths from the transmission grid are to the unit safeguards distribution systems.

Revise specifications 3.7.A 3 and 3.7.B 6 to reficct the new a M

configuration for the Unit 2 480V safeguards bus arrangement.

Enrineered Safety Features Instrumentation Revise specification Tables TS.3.5-1 and TS.3.5-6 to reflect engineered safety features instrumentation limiting setpoints and instrument operating conditions for modifind 4kV safeguards electrical buses. Revise Table TS.3.5 1 to reflect Unit 1 and Unit 2 limiting setpoints for undervoltage protection on 4kV safeguards buses. New setpoints are proposed to reflect replacement of degraded voltsge and undervoltage relays. A new note is added to Table TS.3.5 1 to state that, "** Limiting setpoints are provided for both Unit 1 and Unit 2 in the interim between completion of electrical safeguards upgrades for Unit 2 and later completion of

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ExhiMt A Page 7 of 37 a

electrical safeguards upgrades for Unit 1." Revise Table TS.3.5 6 to reflect the instrument operating conditions for the degraded-  ;

voltage and undervoltage relays on each 4kV safeguards bus.

Revise specification basis 3.5 to add a statement that, " Relays are not provided on 4kV safeguards bus 27 to detect undervoltage and degraded voltage since voltage is monitored on the 4kV source safeguards _ bus (i.e., bus 25 or bus 26) to which it is connected."

Revise specification basis 3.5 to describe upgrades to undervoltage and degt aded voltage protection for the 4kV safeguards buses and to provide the basis for setpoints and time delays selected.

4 Pensons for the Proposed ChaDEta Emergency Di egg.LfcncLa_t.nn Specification _3.7 and specification basis 3.7 currently reflect the plant configuration where two emergency diesel generators, D1 and D2, are shared oy Prairie Island Nuclear Generating Plant, Units 1 and 2. Auxiliary Electrical-Systems at Prairie Island Nuclear Generating Plant are being modified to add two new emergency diesel generators, D5 and D6; and to dedicate the two existing emergency diesel generators, D1 and D2, to Unit 1 and the two new emergency diesel. generators. D5 and D6, to 1 2.

Proposed changes to.specificatios .1.A.5 and to. specification basis

-3.7-also reflect the dedication , the existing _ fuel storage atul supply capability to Unit 1 emerb acy diesel generators and shared.

-diesel-driven cooling water pumps, and the; addition of a dedicated Unit 2 cmergency diesel generator fuel storage and supply

-capability. -These changes also reflect minimum _ volumes of fuel oil necessary for: (1) operation of one Unit 2 emergency diesel _

generator set for 7 days at rated load, and (2). operation of one

,; Unit 2 emergency diesel generator set for 14 days to asnure an adequate fuel oil supply in the event of the. probable maximum flood.

A volume of 75,000 gallons, which conservatively envelopes the two volumes ' calculated, was chosen . for specification 3. 7. A.5 as the minimum onsite diesel fuel oil supply for Unit?2.

-Proposed changes ~to. specification 3.7.A.5 and. specification basis 3.7 reficct a clarification of the Unit 1 fuel oil requirement. The total requirement _ofl70,000 gallons.for D1'and D2 diesel _ generators and-the diesel-driven cooling water pumpsLremains unchanged. We have clarified the specification to indicate that-51,000 gallons of-the 70,000 gallon total requirement for Unit 1 is available for D1 and.D2 diesel generators, The 51,000 gallon requirement is sufficient to. meet the 14 day requirement of diesel fuel oil for the D1 and D2 diesel generators as stated in specification basis 3.7.

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tahlblt A Page 8 of 37 -

t We have chosen not to propone a change to specification 3.7.B.1 I regarding t.he allowed out of service time for one diesel generator  !

i because our evaluation shows that the current limit of 7 days is ,

justifiable. The new confi.uration t will provice several features which are significant enhancements to the e6 sting confi.uration: t (a) The arrangcment of the offsite AC sources to the safeguardu ,

buses will have been improved to reduce the risk of losing offsito AC power to the safeguards buses.

(b) The onsite AC power cyst em will be enhanced considerably in inat a loss.of offsite. power event coupled with the loss of a d5csel generator will be mitigated by the availability of another diesel gnnerator which can be cross tied to the affected 4160 volt safeguards bus. ,

(c) The DS and D5 dicael generators will provide a diverse means of -

providing power to the 416D volt safeguards buses, in addition to simply adding redundancy. With respect to the existing D1  ;

and D2 diesels, DS and D6 were made by a different manufacturer, have differnnt cooling _ systems, different sir.e ratings and will be housed in a separate building located on the oppowite side of the plant. These factors reduce many of ,

the conson failure mechanisms that could otherwise affect all .

l the diesel generators. I In addition, the D5 and D6 diesel engines will be cooled using  !

r4ilators instead of being reliant on a separate ecoling water uystem.

(d) The reliability of the exinting D1 and D2 diesel _ generators, which require a separato enoling water system, will also be l enhanced. Currently, two diesel driven cooling water pumpe are l available following a loss of offsite power event. After '

completion of the SB0/ESU Project modifications, an additiont:1 t.

motor driven cooling water pump will be available, powered from the Unit 2 safeguards buses.

All of these enhancements. greatly reduce the risk of having a ,

station blackout event at Prairie Island. Prior to submittal of the r Prairie Island Individual Plant Examination (IPE), an interim plant.

specific risk assessment has been developed, based ca the PWR Individual Plant Evaluation Methodology (IPEM). Phis study shows that the addit'.on of the DS and D6 diesel generacors and repowering

• of the motor-driven cooling water pump from a safeguards power supply greatly reducer'*he risk of a core melt accident due to station blackout, The E study'results' indicate a core damage

frequency (CDP) for each unit' of slightly less than'1.0E 5/ year.

This figure is lower than the PRA results of many other plants, and  ;

!s due in -7arge part to the increased reliability of the AC power systems offered by_the SBO/ESU Project modifications 1

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I fahlblt A Pap <. 9 of 37 A sensitivity study on the prairic Island IPDi analysis, tollowing the appr oac.. of NUREG/CR 5742, " Feasibility Assessroent. of a Hisk.

Based Approach to Technical Specifications", was performed. This sensitivity sudy generated a hypothetical allowed out of service

] time for one diesel generator of approxiteately 300 hours0.00347 days <br />0.0833 hours <br />4.960317e-4 weeks <br />1.1415e-4 months <br /> (see figure

1) as opposed to the current specification of 7 days (if3 hours).

Thik contrasts with the two reference plants reported in the NL' REG:

the analynis for the first plant yicided a real time risk based i allowed out of-service time of 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> versus its technical specificatio1 limit of 168 hours0.00194 days <br />0.0467 hours <br />2.777778e-4 weeks <br />6.3924e-5 months <br />; the analysis for the sacond plant yielded a real titne risk based allowed out of-service time of 31 hours3.587963e-4 days <br />0.00861 hours <br />5.125661e-5 weeks <br />1.17955e-5 months <br /> versus its technical specification limit of 163 hours0.00189 days <br />0.0453 hours <br />2.695106e-4 weeks <br />6.20215e-5 months <br />.

l The NUREG calculation compares the increase in core damage frequency due to equipment outage to an acceptable limit (5,0E 7). Since .;

Prairic Idand starts with a relatively low CDP. the change in CDP due to a particular component or cortponents being out of service C 11 be less than at other plants.

Due to the enhancements listed in (a) through (d) above, and to tho ,

increase in the calculated risk based allowed out of service time afforded by the enhancements, we believe that the existing energency diesel allowed.out of service time is justifiabic for the new ousite AC power system. Therel'oro, we do not propose to decrease the allowed out of service time for a diesel generator to less than 7 ,

days.

Electrient Safeguards Ungrades In cddit. ion, 4kV and 480V safeguards electrical busca and bus arrangements are being modified. Unit -2 480V safeguards huses are being replaced,-- Replacemeat of Unit 1480V safeguards buses will be Itoplemented at a-later date; therefore, changes reflected in specifications 3,7. A.3 and 3,7,B,6 reflect only the Unit 2 480V i safeguards bus replacement. Additional Technical Specifications changes vill be requested to coincide with completion of 480V bus replacement for Unit 1.

We have taken this opportunity to make changes to specificatlons  !

3,7,A,1, 3.7,B,1, 3.7.B,2, 3.7.B.3, 3.7 B,4 and 3.7.B.5 to clarify that the two separate paths from the transmission grid are to the MDit safeguards distribution systems.

Eogtpet red. S.aff ty Features Instrumnntation 6

( proposed changes to Tables TS.3.5 1 and'TS.3.5 6 reflect upgrades of-  ;

I the undervoltage protection schere per NRC Branch Technical position PSB 1. A separate Technical Specit.ications change will be requested to revise Table TS.3.51 to coincide with completion of 480V.

safeguards-bus replacement for Unit 1.

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4 Fahibit A Page 10 of 37 Changes to specification basis 3.5 have been proposed te state that no undervolt age monitoring is provided for 4kV safeguards hun 27 since this bus will be supplied from either 4kV source safeguards bus 25 or 26 which are monitored for undervoltage conditlonn. This lineup for bus ? ' will provide the safeguards source for the upgraded vertical motor dr!ven coolitig water pump.

Changes to specification basis 3.5 have been proposed to describe upgrades to undervoltage and degraded voltage protection for the 4kV safeguards busca and te provide the basis ftr setpoints and time delays selected.

Stlety EvalwtLimLand_Lhtls.rmitadsn ei Signi fieant 1LW:2r.ily Cen#.ld.,tfauf11's The proposed changes to the Operating Licenses have been evaluated to determine whether they constitute a significant hazards consideratiot as required by 10 CFR Part 50, Section 50.91 using the r.tandards provided in Section 50.92. This analysis is provided below:

1. The proposed amendment will not involve a significant increase in the probability or consequences of an accident previously LXDlWLtRLL SB0/ESU Project tr.odifications as reflected in the proposed Technical Specifications changes were evaluated to determine their impact, if any, on potential t ransients and accident s as described in the Prairic Island USAR. Each trannient and accident was uvaluated in terms of the initigating actions described or assumed in the USAR analysis. The role of the modified systems in mitigating the event was analyzed in order to evaluate whether the modification:

(1) changed, degraded or prevented actions described or sumed in the USAR analysis; (2) altered any assumptions made in evaluating the radiological consequences of the accident; (3) pleved a direct part in mitigating the ra31ological consequences of the accident; or (4) affected any fission product barrier.

The evaluation demonstrated that the USAR transient and accident analyses remain valid and bounding.

As part of the evaluation, the revised emergency diesel generator load sequence was analyzed and found to be bounded by t.he existing analyses.

In particular, the USAR analyses of the loss of offsite power (LOOP) event and the large break loss of coolant accident (LB1DCA) remain valid and bounding. In additlon, the current USAR analysis for the radiological consequences of a LBlDCA remains valid.

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tahlbit A i Page 11 of 37 "

. Further, the plant response to a loss of AC power event is not  ;

degraded as a result of these changes but, in fact, is significantly improved.

In order to determine the offect of the modifications upen the  !

probability and conseguences of an accident, the following items were specifically evaluated:

(1) the applicable design, material and construction ,

< standards;  !

(2) instrumentation accuracles and response times; (3) the equipment operating and design limits, including electrical bus loading, emergency diesel generator f loading and battery loading; ';

(4). the system interfec9s; l (5) voltage.marginst and  :

(6): coordination of protective devices.

Structures, systems and components involved in the modifications '

reflected in the proposed Technical Specifications changes were evaluated as follows: - '

- (1). The design specifications for the new structures, systema-and components were considered for the following requit eaants:

seismic;  ;

separation including control / power circuit interaction, ,

redundancy / separation of systems, and is-olation between safety ar.d non safety circuits:

environmental parametera; F severe meteorological events; missilos;.and ,

fire prutection.

All structures, systems and components meet the appropriate design requirements for their respectivo

classifications.

(2) Structures, systems:and components were additionally i evaluated for the.following:

Structural loads were determined for new cable runs in

. the existing plant and for new cable penetrations in the existing. structures,

, New electrical loads requirements were determined.

System / equipment protectionfreatures have been maintained in the modification. )

4 Support system performance was specified to maintain the safety function of the equipment.

= . System / equipment redundancy and independence-is maintained.

Tho' frequency of' operation of-existing equipment was evaluated and determined not to be affected.

The testing requirements imposed on new structures, systems and co:rponnnts are in accordance with their -

r safety classification.

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i tahlbit A l Page 12 of 37 Failures of systems and components involved in the m.difications were analyced, and it was determined that all safety functions i were maintained.

- The selected diesel generator supplier (Sccidtis Alsacienne de

'- Constructions Mdchaniques de Mulhouse of Franco) was chosen largely based on the very high reliability of their dienel generator sets in nuclear plants around the world. Details '

regarding their reliability are included in a proviets submittal:

Letter f rom Thomas M Parker, Northern States Power Connany to Director of !!uclear Reactor Regulation, U S NRC dsted September l 29, 1989 titled: " Project for Addition of Two Emergency Diesel ,

Generators."

In addition, as discussed on pages 8 and 9, a plant speetftc risk analysis has been performed on the modified plant configuration.

The results of this analysis indicate a risk reduction of approximately 70t in tota) core damage frequency by the addition of the new emergency diesel generucoTA and the upgrade of #121 '

cooling water pump.

Emerr_ency Diesel Generators The plant auxiliary electrical systems modifics.tions provide a greater degree of power source availability for the Prairie i Islano Nuclear Cencrating Plant. As demonstrated by the '

perfermance of a failure modes and effects analysis, no single ,

failure will prevent the modified plant from performing its required safety function in the event of an accident on either unit.

- The minimum diesel fuel supply of 75,000 gallons in Specification 3.7.A.5 for Prairie Island Unit 2 is basad on ,

using the time dependent method of ANSI N195 1976 to calculate the minimum diesel fuel supply necessary to nupply one Unit 2 l cmergency diesel generator set for 14 days to assure a fuel supply in the'avent of a probable maximum flood. ine conservative method of AN91 N1951976 was used to calculate che minimum diesel fuel supply necessary to supply one Unit 2 emergency diesel Senerator set for seven days at rated lond of 5400kW, which is significantly above the maximum predicted load for a Unit 2 emergency diesel generator. The calculated mieletm volume - for seven day- operation of one Unit 2 emergency- '

diesel generator set uuing the contervative method of calculation was less than the minimum volume necessary for 14 day operation calculated using the time _ dependent method. A conservative volume-is proposed in spacification 3.7.A.5 as the required minimum fuel supply for Unit 2' emergency diesel

• generators. This minimam volume envelopes the 7 day and the 14 l day requirements.

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Dhlblt A j Page 13 of 37 The clarification of rpecification 3.7.A.5 to state the $1,000 gallon diesci funi oil requirement for voergency diesel .

generators D1 and D2 and to restate the total Unit I diesel l

fue:1 oil supply requireinent of 70,000 gallons for the D1 and D2 diesel generators and the dient1 driven cooling water pumps is

onsidered an administrative change. This change is considered admintotrative in that it does not reflect any change to the  !

physical plant or any change to the opera: ion of the plant and as such is not considered to affect the probability or 1 consequences of an accident previously evaluated. i i

I Electrical Saferuards Uny,r, ming -

Required engineered safoguards features loads are accommodated with the improved auxiliary electrien1 systems configuration; and, as demonstrated by the performance of a failure modes and ,

affects analysis, no single failure will prevent the modified plant from performing its required safety function in the event i of an accident nn either unit.

Specifications 3.7 A.1, 3.7.B.1, 3.7.B.2, 3.7.B.3, 3.7.B.4 and ,

3.7.B.5 are bein6 revised to clarify that the two separate '

paths from the transmission Brid are to the Unit, rather than plant safeguards distribution syatem. This change is considered administrat.ive in that it does not reflect any change to the physical plant or any change to the operation of the plant and as such is not co;isidered to affect- the  ;

probability or consequeness of an accident previously evaluated.

EDrineered Sq,[gtv Features Instrumentation Changes to Table TS.3.5 1. reflect new setpoints for 4kV safeguards bus degraded voltage and undervoltage relays.

Instrument operating conditions for these relays are reflected ,

on revised Table TS.3.5 6.

I The new setpoints and respectivo time delays have been established based on the guidance in NRC lirnach Technical Position PSB-1, " Adequacy of Station Electric- Distribution

, System Voltages," dated July _1981. The undervoltage protection scheine reflected in these proposed changes provides for e detection of undervoltage and degraded voltage conditions at the 4kV safeguards bus level.  !

Upon receipt of an undervoltage signal, the automatic voltage restoring scheme-is cetuated after a short time delay. This time delay prevents actuation during normal transients (such as motor starting) and allows protective relaying operation during faults.

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Pese H of 37 The degraded voltage scheroe provides two separate time delays.

Per Branch Technical position PSB 1, these time delays aro selected as follows:

(1) The first time delay was selected to establish the existence of a sustained der,raded voltage condition, i.e., a duration greater than the longest expected voltage dip resulting fiorn Class 1E motor starting.

2 (2) The sscond time delay was established in a range liinited so that permanently connected Class 1E loads would not he darnaged, tihen degrad9d voltage is sensed. two tirne delays are actuated.

Logic actuation following the first time delay annunciates that a t.ustained degraded voltage condition exists and enables logic l which will ensure that voltage and timing are adequate for _i safety injection loads by automatically perforrning the j following upon receipt of a safety injection signal:

(1) Auto start the diesel generatori (2) Separate Lt.e bus from the grid; ,

(3) Inad the bus onto tho dicsol generator; and (4) Start the load sequencer (including safety injection loads), t The second longer time delay is used to allow the degraded voltage condition to be corrected by external actions within a tirne period that will not cause damage to operating equipment, If voltage is not restored within that time period, the logic automatically performs the following:  ;

(1) -Auto start the diesel generator; (2) Separate the bus from the grid; (3) Land the bus.onto the diesel generator; and i (4) Start the load sequencer.

For the reasons discussed above, the proposed amendment does not significantly increase the probability or consequences of an accident previously evaluated.

2. The proposed amendment will not create the possibility of a now or

$11.f ferent_,.kj,pd of accidegfrorn any accident previousl" eval at3fL.

^

The SB0/ESU Project roodifications as reflected in the proposed Technical Specifications changes were evaluated to determine if they could create the possibility of a new or different kind of accident frora any accident previously evaluated, The modifications were evaluated to determine the types of accidents which could result frern malfunction of the new/ modified structures, systems and components. It was determined that no new  ;

i or different kinds of accidents from those previously evaluated are created. USAR analyses remain bounding,

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l Eshibit A i Page B of 3/

Emergenev Diesel Genera,t.gts The modifications as reflected in the proposed Technical i Specifications changes were evaluated to determine types of failure modes which were not previously evaluated. As a '

result, the following was determined: ,

(1) Radiator cooling for the new UnAt 2 diesel genetatora '

is provided instead of the heat exchanger coolit.g ,

utilfred for the existing diesele. It has been determined that these radiators can perform their safety fcction, ,

(2) The nes ...,arquencers for the safeguards buses are c programmaote solid state devices. These devices will have validation and verification performed for the '

logic and will be tested to ensure that they are  !

capable of performing their safety function in he  ;

plant electromagr. etic / radio environment. '

The clarificatJon of specification 3.7.A.5 to state the $1,000 I gallon diesel fuel oil requirement for emergency diesel

_ generators D1 and D2 and to restate the total Unit 1 diest1 fuel oil supply requirement of 70,000 gallons for the D1 and D2 dicuel generatorn and the diesel-driven coolin5 water ptuips is considered an administrative change atd as such doce not create the possibility of a new or difforent kind of accident from any +

accident previously evaluated.

E l e e t r i e a 1 S a f e gu a r. gly._))II,r.ailta The modificat. ions as reflected in the proposed Technical _

Specifications changes were evaluated to determine types-of failuro modes which were not previously evaluated. It was determined that the nov 480V safeguards buses will be provided ,

with voltare regulatorc which employ programmable solid state control desicos. . The postulated failure modes _of the voltage regulator include overvoltage-and undervaltage conditions outside the operating range of the equipaent powered by the .-

bus. The effects of such failures ate bounded by-the compiere

- los.1 of a safeguards train, which is postulated in the current plant design.

i Changes to specifications 3.7.A~.1, 3.7.B;1, 3.7 B.2, 3.7.B;3,

- 3.7.B.4 and 3.7.B 5 which clarify that the two separate paths from the transmission grid are to the Mni.t rather than plant safeguards distribution system are considered ndministrative and as such do not create the possibility of a new or Jifferent-kind of accident from at.y accident previously avaluated.

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i tahlbit A l hye M of M Fuginet red Safet v reatures Instrtuwntntion  !

The proposed changes to Tables TS,3.51 and T!i.3.5 6 do not introduce any basic chan6es in plant operation. The ability to detect and protcet against 4kV safeguards bus undervoltage ,

conditionc is maintained for the new auxiliary electrical synems configuration. i For the renoons discussed above, the proposed amendment does not create the possibility of a new or different kind of accident from any accident previously evaluatad.

3. The proposed amendment will not involve a significant reduction in ,

the trargin oLgutfaly. ,,,,, . . . . ,

i Egergency Diesel CCDe rat or s l The auxiliary electrical system for each unit has the capacity to start and operate sufficient safeguards equipment to  ;

maintain adequate cooling of the fuel and to maintain containment. pressure within design limits le t.he event of a LOCA. Tha new Unit 2 emergency diesel gene.ators were sized to ,

meet this requirement, to provide capacity to power the vertit.a1 motor driven safecuards cooling water pump and tn c provide additional marSin for future loads.

The new Unit 't diesel fuel oil storage tanks provide' sufficient capacity to supply both emergonet diesel generators for seven days at rated load. As stated ab9v% the minimum fuel oil cupply of 75,000 gallons vill supply one Unit 2 emergency diesal generator set for seven riays at a rated load of $400kW, ,

which is significantly aoove !.he maximum predicted load for a '

Unit 2 cmergency diesel generator set. . Further, this minimum fuel oil supply of 75,000 gallons will supply one Unit 2 emergency diesel' generator set" for 14 days at a load calculated per the time dependent method of ANSI N195 1976.-

These changes improve the margin of safety for each unit and improve the overall margin of safety. for the _ Prairie Islard Nuclear Generating Plant by'providing increased onsite AC power

-availability, by dedicating two emergency diesel generators to. '

each-unit and by providingltwo emergency diesel generators that. i are not dependent on the cooling water rystem. -

The clarification of specification 3.7.A.S to state the 51,000' .

Sallon diesel fuel oil requirement.for emergenay diesel generators D1 and D2 and to restate the total Unit:1 diesol fuel oil supply requirement of 70,000 gallons for the D1 and D2 diese1= generators and the diesel-driven cooling water pumps la .

considered an administrative change and as such does not_ affect.

the margin of safety.

~ . ~ . . - ._c-.--- --.- .-.,.-~ _ .- --.-=_, - . --

l taMbit A Page iT of 37 Electrical _infecunrds Upgrades i The new Unit 2 480V safccuards configuratinn .secamplit;hes tho ,

iollowin6; (1) provides additional citeult breakers ter improved HCC feeder circuit coordination by eliminating suhfed 480V l MCOs from raieguards 480V 'uuses; and (2) improves voltage regulation at the 480V icvel.

Changes to specifications 3.7.A.1, 3.7.B.1, 3.7.B.2, 3.7.B.3, 3.7.B.4 and 3.7.B.5 which clarlfy that the two separate paths from the transmission grid are to the unit rather than gi n sofeguards distribution system are considered administrativo and as such do not offect the margin of safety.

J:ngineered S de_tv Teatures huLRV.UM 1.a11PIl 4

in determining the revist'd 4kV safeguards bus undervoltage and ,

degraded voltage protection setpoints for Table TS.3.5 1, ,

criteria and equipment voltano requirement assumptiour, used in the calculation of the new setpoints were essentially the same as those used te calculate the existing setpointa. ,

T'.te degraded voltage protection setpoint remains at 90 1 2% of I nominal 4160V safeguards bus voltage for Unit 1, A separate License Amendment Request wJll be provided to revise this setpoint to coincide with later replacement of the 480V safeguards busca. The degraded voltage protection setpoint selected for Unit 2 is 87.5 1 3.5% of nominal 4160V safeguards bus voltage. Testing and analysis have shown that all safeguards loads will operate properly at or above the minimum degraded roltage setpoint. The maximum degraded voltage setpoint is chosen to prevent unnecessary actuation of the voltage restoring _ scheme at the minimum expected grid voltage.

The first degraded voltage time delay of 8 1 0,5 seconds has been shown by testing and analysis to be long enough to allow for normal transients (i.e., motor starting and fault clearing). It is also longer than the time delay required to star c the aafety injection pump at minimum voltage. 1he second degraded voltage time delay is provided to allow the degraded voltage condition to be currected within a tiue frame which vill not-cause damage to petaanently connected equipment.

The undervoltage serpoint is 7512.5% of rominal bus voltage.

The minimum setpoint ensures equipment operates above the limiting value of 75% (of 4000V) for one minute operation. The 75% maximuu sotpoint is chosen to prevent unnecessary actuation of the voltays restorin6 scheme during voltage dips which occur during motor starting. The undervoltage time delay of 41 1.5

, seconds has )etn ahown by testing and analysis to be long enough to allow for normal transients and short enough to

. . _ . . . _ _ - - - .- ~. - . - - _ _ _ . _ . . . - _ _ _

Enhibit A Page 18 of 37 operate prior to the degraded voltage logie, providing a rapid transfer to an n'iternate source.

The existing margin of ssfety has been analntained by the proposed setpoints and tinm delays for 4kV safeguards bus undervcitage and degraded voltag.e protection.

For the reasons discussed above, the proposed auiendnient does not involve a s.tgulficant reductien in the snargin of safety.

. Pnsed on the eumluation described above, and pursuant to 10 CTR Part 50, section 50.91, !Jorthern States Power Company has deterniined that operation of the "rairie Island Nuclear Cencrating Plant in accordance with the proposed License Amendment Request does not involve eny significanc har.ards considerations as deflued by NRC regulat!ons in 10 CPR Part S0, Section 50.92.

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b. Technical specification 4.6 Technical Specification Basis 4.6 Ernoosed Chonges Revise specification 4.6.A.1.c to reference ASTM D975-77, " Standard Specification for Diesel Fuel 011n," rather than the 1968 version, for specification of acceptable diesel feel oil limits.

Rcvise specification 4.6. A.1.e to add monthly surveillance- tests for the new Unit 2 emergency diesel generatora, DS and 06.

Revise specification 4.6. A.2.c to add neni-annual surveillance tests for the new Unit 2 emergency diesel generators.

-Revise specification 4.6. A.3.b.3 to add 18 month surveillances to .

verify that auto cot.nected loads do not exceed the tested capacity of the new Unit 2 emergency diesel generators.  ;

Revise specification 4.6. A.3.c to add 18 month surveillance tests for i th- 'ew Unit 2 emergency diesci generators .

Revise specification 4.6.A.3.d to add 18 month surveillances to ver!Iy

~ the capability of each of the new Unit 2 emergency diesel generators to reject the single largest emergency load without trippinF.

Revise specification basis 4.6 to specifically state that the load '

rejection test will demonstrate tha capability of each emergency diesel generator to reject the single largest-emergency;1oad without

. tripping; t Revise specification basis 4.6 to ref.1 et the-new emergency diesel ,

. generator configuration of two emergency diesel generators per unit, j t ,

- Revise 4.6.A.1.e and'4.6.A.2.a to remove'the specific engine speed' which in the " synchronous' speed" for these surveillances.

Revi.=e 4.6.A.1.e and 4.6.A 3.b.2 to correct npelling' errors.

Evasons for the Prgeosed Chances p Specification' 4.6. A.1.c ~ currently reficcts the~ monthly surveillances .

j for diesel.gonerator fuel oil sampling. This specification has been ~

revised to reflect use of the 1977. version offASTM D975'for l: . . .

l specification'of acceptable diesel fuel 011 limits as recommended by NRC Regulatory Guide 1.137 Revision 1.

l

- Specification 4.6. A.1.e currently reflects monthly surveillances for .

1 - emergency diesel generators 01 and D2. This specification has been l revised to reficct monthly surveillances for new Unit 2 emergency l diesel. generators 35 and D6.

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j tahtbit A Page 10 of IT Specification 4.6.A.2.c currently reficcts semi annual surveillance tests for emergency diesel generators D1 and D2 Thist speellication has been revised to reflect sett! annual nurveillance testa for the new Unit 2 cmergency diesel generators D5 and D6.

I specification 4.6.A 3.b.3 currently reflects the 18 month I surveillances to veri fy auto cennected loads f or c.nergency diesel generators D1 and D2. This specification has been tovised to reflect the 18 month surveillances to verify that the auto connected loads for ,

emergency diesel bencratora D$ and D6 do not exceed the tested 1 capacity of the new Unit 2 emergency diesel benerators.

Specification 4.6. A.3.c currently reficcts 18 month surveillemco test s '

for emergency diesel generators D1 and D2. This specification has been revised to reflect 18 month surveillance tests for emergency l diesel generators D5 and D6. .

Specification 4M.A.3.d currently reflects the 18 month surveillances to verify the capability of emergency dissel generators D1 and D2 to  !

reject the largest single emergancy load without tripping. This  :

spe<:ification has been revised to reflect the inrgest singic ometgency  ;

Icad for surveillance testing of t.he new Unit 2 emergency diesel i generstors DS and D6. l Finally, wo have taken this opportunity to make certain minor administrative changes to s,pecification 4 6 to correct spelling errors ,

anu to clarify the specification. The clarificatien is made in specifications 4.6.A.1.e and 4.6.A,2,n to remove the specific engine  !

speed which is the " synchronous speed."

Safetv Fraluation atuLDetermination or sinnifican.LAtiatnh p,g.ng ide ra t Iqt13, -

l The proposed changes to the Operating Licenses have been evaluated to determine whether they constitute a significant hazards consideration -

es require.t_by 10 CFR Part 50, Section 50.91 using the stanc<irds provided in Section 50.92. - This analysin in provided below:

1. The proposed amendment will not involve a significant increuse in the probability or consequences of an accident previously l evaluated. L

^

Emergency diesel generators are required to have s fficient

- capacity.and capability to ensure that_ acceptable .uel design limits and design conditions of the reactor coolant pressuru boundary sto not exceeded as a result of anticipated operational 3 occurrencen. Further, emergency diesel generators are reqaired to have sufficient capacity and capability to ensure that the core is _

cooled and that contalument integrity and other vital functions ,

are maintained in the event of postulated accidents.

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e i EAhlblt A Page 21 of 37 Emergency diesel generator tenting and surveillance demonstrate during monthly, semi-annual and 18 month tests and surveillances )

that the emergency diesel generators are capable of performing ,

I their design safety function. Diesci fuel oil quality is determined by monthly surveillance sampling.

J Tests and surveillances fur new emergency diesel generators D5 and  ;

D6 will be perforn.ed at the same frequency as current '

specification 4.6 testa and surveillances for emergency diesel generators D1 and D2. Equivalent testing requiren.cnts will be maintained for emergency diesel generators D5 and D6.

proposed revisions to the following specifications are considered- i administrative and as such are not considered to affect the j probability or consequences of an accident previously evaluated: j (1) specifications 4.6.A.1.e and 4.6.A.2.a to remove the '

specific engine speed which is the " synchronous speed";

I and (2) _ specifications 4.6.A.1.e and 4.6.A.3.b.2 to correct spelling errors.

For the reasons discussed above, the proposed amendment does not i significantly increase'the probability or consequences of an ,

accident previously evaluated.

2. The preposed amendment will not create the possibility of a new or different kind of accident;, from any accident oreviousiv analvred. 1 Testing and surveillances proposed by these speciff.ation change's do not constitute new modes of operation for emergency diesel generators since the testing and surveillances proposed for Unit 2

emergency diesel generators D5 and D6 are equivalent in type and frequency to those- performed for emergene.y diesel generatorn D1

'- and 92.

Administrative changes described in 1. above are not considered to create the possibility of a new or different kind of accident fto.n -

any accident previously evaluated, (J For the reasons discussed above, the proposed amendment does not creato the possibility _ of a now or diiferent kind of acciderit from any accident previously evaluated,

~

j! 3. The proposed amend nent will not i.ivolve a significaat reduction in c .the martin of safety. __ .

I- Monthly surveillances of fuel oil quality vili provide assurance ,

l that: stored fuel oil maintains.necessary quality limits. -Use of fuel _ oil quality acceptance _ limits of ASTM D975-77 will not ,

j decrease the margin of safety maintained by currently specified j acceptance limita.

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Page 22 of 37 Testing and surveillance of Unit 2 emergency diesel generators DS and D6 at the loads specified will provide assurance that the r emergency diesel generators are capable of supplying their required safeguards loads, while remaining capable of supplying 3 these loads for the length of the fuel cycle.

Proposed changes to specifications 4.6.A.I.e, 4.6.A.2.c and 4.6.A.

• 3.c require monthly, semi annual and 18 month surveillance testing for Unit 2 emergency dierol Generators to assure that the emergency diesel generatora have the capability to start, accelerate to synchronous speed and accept load.

The proposed aonthly, semi annual and 18 month surveillance testa ,

in specifications 4.6.A.1.e, 4.6.A.2.c and 4.6.A.3.c involve loading ene.h Unit 2 emergency diesel generator to between a minimum of $100kW and a maximum of 5300kW. The minimum 5100hW test load has been chosen to assure that either Unit 2 emargency diesel generator has the capacity and the capability to assume the maximum auto connected load for Unit 2. The maximum 5300kW test i

, load has.been chosen to provide a load test range for operational test flexibility during the surveillance test.

The minimum 5100kW test load in specifi;ations 4.6.A.1;e, "

4 6.A.2.c-and'4.6.A.3.c also corresponds to the load proposed for the specification surveillance 4.6.A.3,b.3. It should be noted that, although 5100kW is not the continuous rating of the Unit 2 energency diesel generators, it is significantly above the maximum auto-connected load. The current maximum auto-connected load is r mote than 1000 kW under the-5100kW minimum test load-for the Unit 2 emergency diesel generators. Therefore, the proposed specification 4.6.A.3.b.3 requirement to verify that the auto-connected loads do not exceed $100kW for each Unit 2 emergency ,

diesel generator is quite conservative.

Finally, specification 4.6.A.3.d has been revised to state the surveillance test load for the Unit 2 emergency diesel-generator load rejection test. The load rejection test will demonstrate the ,

capability of each Unit 2 emergency diesel generator to reject _ the ,

single largest emergency load (i.e., the_vnrtical motor-driven. '3 safeguards cooling water pump) without tripping. A test load of

- at least- 860kW will demenstrate this capability. -

Administrative changes described in 1. above do not affect the margin of safety.

For the' reasons discussed above, the proposed amendment does not I involve a significant reduction in the margin of safety.

- Based on the evaluation described above,'and pursuant to 10 CFR Part

50. Section.50.91, Northern States Power Company has determined that operat'an of the Prairi.e Island Nuclear Generating Plant in accordance e- g o spg. - =g v g - y e tc ge p-e gygg ey v g-m y g-ehtpa-gp f ,--9s-5 -Y M W4 'TF

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Page 23 of 3T j with the proposed License Amendment Request does not involve any  !

significant harards considerations as defined by 14RC regulations in 10 CFR Part 50, Section 50.92, i

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2. Coolitu* Water "ygt. ctg ,

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a. IfIhnical.Spreification 3.3.D l Iechnien1 Specifica*fon jasis 3.3 l'ERE21cd Changc.3 ,

Changes are being proposed to specification 3.3.D and specification ,

basis 3.3 to reficct the availability of the upgraded vertical motor.

driven (s121) cooling water pump as a safeguards cooling water pump ,

which can be used an an equivalent replacement for either of the diesel driven saf"Buards cialing water pumps.

Replace specificctions L 3.D.1.a and b with a new specification 3.3.D 1.a to require f our of the five cooling water pumps t o be OPERABLE. Specification 3.3.D.1.a. as proposed, requires that certain conditions be met if the inoperable cooling water pump is one of the .

diesel driven safeguards cooling water pumps (i.e., when the upgraded '

vertieni motor-driven cooling water pump is used as an equivalent ,

replacement for one of the two diesel-driven safeguards cooling water j pumps). If the inoperable con 11ng water punp in one of the diosci- ,

P iven coolin6 water pumps, then s,121 cooling water pump shall be aligned as shown in the table below (see Figure 2). All changes in valve positions shall be under direct administrative control.

Inoperable Valve Alignment Power Supply to Pump j Bur 27 (#121

,1 _ Cooling Vater pump)

1. 12 HV 32037 or MV 32036 closed; and Cooling associated Bkr Locked Off

^

Water Purnp Bus 25 HV 32034 and MV 32035 open; and both Bkrs Locked Off

1. 22 MV.32034 or MV-32035 closed; and Cooling -

the associated Bkr locked Off '

Water Pump Bus 26 MV 32037 and MV-3203b open; and ,

lboth Bkrs 1.ocked off _

Revise specification bania 3.3 to state that specification-3.3.D.1.a assures that an_ automatic safoty injection signal to the cooling water header isolation valves will not align both OPERABLE safeguards pumps to the same safeguards train.

Revise specification bawis 3.3 to state that specification 3.LD.1.a also assures. that the vertical motor driven (s121) cooling water purrp is aligned to provide cooling water to the same train as the train from which it.is powered.

- - ____ - ~ ---.- - - - -

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9

Enhildt A tape M of 3r Rentunber specification 3. 3.D 1.c as 3. 3.D. I .b.

Add.a new specification 3.3.D.1.c to clearly reflect the existing  ;

requireinent for two cooling water headers to be OPERABLE. ,

r Add a new specification 3.3.D.1.d to require the 19,000 gallon minimum '

fuel supply in the interconnected stora6e tanks for the diesel driven cooling water pumps. Furtner, new specification 3.3.D.1.d notes that r the 19,000 gallon requirement is included in the 70,000 gallon total diesel fuel oil requirement of specification 3.7.A.5 for Unit 1.

Revise the specifleation and basis 3,3 to include this minimum funi '

supply and to clarify that the 19,000 gallon tequirernent is included in the 70,000 gallon total onsite requirement of specif ication 3.7. A.5 i for Unit 1.  !

Replace specifications-3.3.D.2.a and b with a revised specification ,

3.3,D.2.a to reficct a limiting condition for operation when two of l the five cooling water pumps are inoperabic. Specification 3.3.D.2.a. '

. as proposed, requires that certain conditions be met if the two inoperable pumps are safeguards pumps (i.e., #12 cooling water pump, i

1. 22 cooling water pump, #121 cooling water pump). The conditions to be met are:

-(1) the engineered safety features associated with the OPERABLE safeguards cooling water pump ate OPERABLE; and i (2) both paths from the transmission grid to the unit 4KV  !

safe 6uards buses are OPERA!>lE (applicable to Unit 1 operation only); and (3) -this condition of inoperability (i.e., two safeguards pumps

• inoperable-simultaneously) may not exceed 7 days in any-consecuti t 30 day period.

Renumber specifications 3.3.D.2.e, d, e and f as 3.3.D.2.b, c, d i and e.

! . Revise specification basis 3.3 to reflect that cooling water can be supplied by either of two horizontal motor driven cooling water pumps, ,

by a saf eguards rnotor driven pump or by either of two safeguards diesel driven pumps.

Ecftsens for the Prop,gged Changes The vertical motor driven cooling water ptunp is beitig upgraded so:that is can be used as a safeguards cooling water pump, This vertical motor driven safeguards cooling-water pump will-be an equivalent replacement for either of the.two existing diesel driven safeguards ,

. cooling water pumps. Changes to specification 3.3.D 1 and 3.3.D.2 '

have been proposed to reflect the availability of this third L safeguards cooling water. pump and to simplify the specifications.

l'

4

( Ahlbit A Page 76 of 31 Revised specification 3.3.D.l.a requires four of the five cooling water pumps to be OPERABl.E. When it is necessary, this revised specification will allow any one of the five cooling water pumps to be out of service for maintenance without degrading the Technical Specification required cooling water system. The one out of five pumps may be a safeguards pump or a nonsafeguarda pump.

Revised specification 1.3.D.I.a specifies additional requirements if the inoperable cooling water pump is one of the diesel driven safeguards coolir.g water purops. In that caso, the following requirements are necessary so that the vertical motor driven cooling water pump can be used as an equivalent replacement for the inoperable diesel driven safeguards cooling vater pump:

If the inoperable cooling water pump is one of the diesel driven cooling water pumps, then #121 cooling water pwnp shall be aligned av shown in the table below. All changes in the valve positions shall be under direct administrative control.

inoperable Valve Alignment power Supply to pump ins 27 (ul21 Cooling Water pumpi

1. 12 MV 32037 or MV 32036 closed; ann Cooling associated Bkr Locked off E

HV 32034 and MV 32035 open; and both Bkrs Locked off

1. 22 MV 32034 or MV 32035 closed; and cooling the associated Bkr. Locked off MV 32037 and MV 32036 open; and both Bkra Locked off

, These proposed changes arisure that the_ cooling water hender isolation i valves are properly aligned so that #121 cooling water pump functions

as an equivalent replacement for the inoperable diesel driven cooling

! - water pump, thus maintaining redundant cooling waiter supply capability. These proposed changes aosure that un automatic safety i injeciton signal to the cooling water header isolation valves will not

! - align both OPERABLE safeguards pumps to the same uafeguards train.

i These proposed _ changes also assure that #121 cooling water pump is

! aligned to provido cooling water to the same train as the train from which it is powered.

i I

New specification 3.3.D l.c is added to clearly reflect the existing Technical Specifications requirement for two cooling water headers to s be OPERABLE. This 1$ not a new requirement since specification

! 3.3.D.2.c currently irovides the limiting condition for operation with j one of the two required cooling water headers inoperable.

=

Ikhibit A Peue 27 of 37 Specification 3.3.D.1.d ic being revised to specifically acknowledge the requirenent for a minimua fuel supply of 19,000 gallons for diesel driven cooling water pumps. Existing Technical Speciffcations include this minimuin fuel supply as part o'. the 70,000 gallon total required by specification 3.7.A.5 for Unic 1. Based on the Technical Specifications changes proposed in this request, it is prudent to clarify this requirement by specifically adding it to specification 3.3.D. This is not a new requirement but is a clarification of the existing Technient Specifications reouirciment.

Revisnd specification 3.3.D.2.a reficcts a limiting condition for operation when two of the five cooling water pumps are inoperable.

per the revised specification, two of the five cooling water pumps may be inoperable for 7 days, whether the pump is a safeguards ptunp or a nonsafeguards ptump.

Revision t o specification 3,3.D.2.a. (1) reflects deletion of what was a confusing reference to the " associated diesel generator." The Technical Specifications definition of the term "0PERABLE" states in part:

A system, subsyr, tem, train, component or device shall be OPERABLE l or have OpERAB7LITY when it is capable of performing its specified function (s), implicit in this definition shall be the assumption that all necessary attendant instrumentation, controls, normal and emergency electrical power sources, cooling or seal water, <

-lubrication or other auxiliary equipment that are required for the  !

system, subsystem, train, component or <!evice to perform its ,

function (s) are also capable of performing their related support t function (s).

In revised specification 3.3.D.2.a.(1), the istplicit assumption is that an _ emergency power source associated with the OPERABLE safegusrds ,

cooling water pump is available (i.e., the appropriate Unit 2  :

emergency diesel generator is available to power the vertical motor-driven safeguards cooling water ptump). And when this specification requires engineered safety features associated with the operable safeguards cooling water pump, it is an implicit assu ption that the engineered safety features (and their associated emergency diesel generator) associated with the OPERABLE safeguards cooling water pump are OpERABLEi An an example, if the vertical motor driven safeguar:ds cooling water ptunp was the remaining safeguards cooling water pump under specification-3.3.D.2,a, then revitSd. specification 3.3.Di2.a.(1) would require:

-(1) vertical-motor driven safeguards cooling water p'unp (aligned to one train of engineered safety features) and the anaociated Unit 2 emergency diesel generator; and '

(2) engineered safety foctures associated with the OPERABLE .

safeguards' cooling water pump and the Unit 1 or Unit 2 emergency diesel generator associated with the OPERABLE engineered safety features train on Unit 1 or Unit 2, ,

respectively, i

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j Eshibit A j Page 28 of 37 i Specification 3,3.D.2.a is being revised in specification  ;

! 3.3.D.2.a.(2) to specifically apply to Unit I since diesel generators  !

D1 and D2, which require cooling water system flow, are being '

dedicated to Unit 1. Unit 2 diet,el generators D5 and D6 do not require coolint, water system support and, therefore, loss of redundancy in the cooling water systein does not degrade the Unit 2  ;

onsite emergency AC power system. '

Ve have also taken this opportunity to make a change in revised specification 3.3.D.2.a.(2) to clarify that both paths from the transtnission grid are to the unit rather than El. ant 4kV safeguards buses.

Revised spectilcation 3.3.D.2.a.(3) acknowledges the more restrictive .

condition of inoperability (i.e., two safeguards purops inoperable simultaneously) and restricts this condition of inoperability so that it may not exceed i days in any consecutive 30 day period. This revised specification retains this restriction froin the current specification 3.3.D.2.n.

For editorial reasons, specifications 3.3.D.2.d, e, f and g have been renumbered as 3.3.D.2.c. d, e and f.

Egfety Evaluation und Determination of Sirnificant llaunLq Considerations The proposed changes to the Operating Licenses have been evaluated to determine whether they constitute a significant hazards consideration as required by 10 CFR Part 50, Section 50.91 using the standards provided in Section 50.92. This analysis is provided below:

, 1. The proposed. amendment will not involve a significant increase in

• the probability or consequences of an accident previously evaluated.

The existing vertical motor driven cooling water pump and supporting systems are being upgraded to safeguards classification t

as part of the SB0/ESU Project. This upgrade as reflected in the proposed Technical Specifications changes was evaluated to determine its impact, if any, on potential transients and accidents as described in the Prairic Island Nuclear Generating Each transient and accident was evaluated in terms of Plant USAR.

the mitigating actions described or assumed in the USAR analyses.

The role of the upgraded systems and components in mitigating the event.was analysed _to evaluate whether the upgrade:

(1) changed, degraded or prevented actions described or assumed in the USAR analysis; e

_(2) altered any assumptions made in evaluating the radiological consequences of the accident; (3) played a direct part in mitigating the radiological L consequences of'the accident; or I

L

_ -_ _ _ _ _ . . . - - . . , . . _ _ _ _ - . _ . . _ _ . _ . . _ _ _ _ . . _ . -,._,.___r -,

t i

I' fahlbit A Page 29 of 3F (4) affected any fission product barrier, i

The evaluation demonstrated that the USAR transient and accident ,

analyseo remain bounding, j r

The proposed Technical Specifications changes to specification '

l 3.3.D and specification basis 3_3 do not degrade the capability of the cooling water system to function as currently required by Technical Specifications. The upgrade of the vertical motor-driven cooling water pump and supporting systems / components  ;

provides a diverse means of satisfying the requirement for cooling c water to engineered safety features equipment.

In order to determine the effect of the upgrade upon the probability of an accident, the following items were specifically evaluated; '

(1) the applicable design, material and construction standards; (2) instrumentation performance; _

r (3) the equipment operating and design' limits, including not  !

positive suction head (NPSH) reqairements for the ,

vertical motor driven cooling water pump; and  ?

.(4) the system interfaces.

A detallod' evaluation was performed to determine that the upgraded vertical-motor driven cooling water pump and its support systema / components can function as an independent, diverse means of providing cooling water- to engineered safety features equipment. The'following areas were:specifically evaluated:

(1) seismic design end seiamic qualification; (2) separation, including control / power circuit interaction,-

redundancy / separation of systems, and. isolation between safety and non safety circuits; (3) severe meteorological events; -

(4) .tissiles; (5)- internal flooding; and (6) -fire protection.

The following additional actions were taken as part of the ,

upgrade; (1) Emystem/ component protection features were maintained in the~ upgrade;

(2) support system performance was verified;

-(3) system / component redundancy and independence was' assured where required; and (4) operation and-testing history for the vertical motor-drivencoolinglwaterpumpwasevaluated.

Failures of systems and components involved in the uP6rade were analyzed to determine if the safety function could be assured. It '

L

. _ _ . , _ _. _ _ . . . _ _ _ . ~ . _ ___m. ._ _ _.__ _ . _ _ _ _ _ _ _ _ _ _ . _ _ -

i i

9 i

tahibit A l Page 30 of 37 l

., was deterrained that all requi:ed safety functions could be assured.

I Specifiention 3.3.D.1.a simplifies previous specification 3.3.D.1.a and b and is being revised to require that cooling water i header isolation valves be prealigned and adrainistratively -

controlled whenever the vertical rnotor driven cooling water pump '

is being used as a safeguarda pump. This prealignment does not increase the probability or consequences of an accident previously evaluated since the prealignment places the cooling water header

- isolation valves in the positions required to respond to analyzed events.

t Specification 3.3 D.I.d is being added to clarify the ininimum fuel supply requirement of 19,000 gallons for the diesel-driven cooling water purnps. This change is conoidered adrainistrative in that it I does not reflect any change to the physical plant or any change to I the operation of the plant and as such is not considered to affect l the probability or consequences of an accident previously i evaluated.

b Itevised specification 3.3.D,2.a simplifies the previous specification.  ;

Specification 3.3.D.2.a.(2) specifically applies only to Unit I since the existing diesel Generators, D1 and D2, are being dedicated to Unit 1; at.d the new Unit 2 diesel generators, DS and D6, do not require cooling water system flow. This is considered an administrative clarification and as such in not considered to

- affect the probability or consequences of an accident previously evaluated.

Specification 3,3,D.2.a.(2) clarifles that both paths frorn the

! transmission grid are to the unit rather than plant 4kV safeguards '

busca. This change is concidered administrative in that it does not reflect any change to the physical plant or any change to the operation of the plant and as'such is not considered to affect.the probability or consequences of an accident previously evaluated. .

- For the reasons discussed above, the proposed amendment does not significantly increase the probability or consequences of an accident previously evaluated.

l

2. The proposed amendment will not create the possibility of a new or different kind of anident from any accident previousiv evaluated.

The upgrade of the vertical motor driven cooling water pump and  !

supporting sys". ems reflected in the proposed Technical Specifications changes was evaluated to' determine if it could create the possibility of 'a new or dif ferent kind of accident from any accident previously evaluated.

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• f lahibit A i Page 31 of 37 ,

t The upgrade was evaluated to determine the types of accidents which could result from malfunction of the upgraded systems and -

i components. It was determined that no new or different kinds of  ;

I accidents from those previously evaluated are created. USAR  !

analyses remain bounding.  ;

l In addition, the upgrade reflected ao proposed Technical  !

Specifications changes was evaluated determine types of failure  !

modes which were not previously evaluated. The following failures l L were evaluated: I l

(1) failures in the power supplies to 4kV safeguards bus 27  :

(on which the upgraded cooling water pump .is loaded) from '

AkV safeguards buses 25 and 26; (2) failure of the 4kV safeguards bus 27 itself; i l (3) failure of the _ power supply cable to the vertical motor-l driven cooling water pump; i (4) failure of the pump speed switch at either diesel driven  ;

l cooling water pump; '

(5) loss of DC control power to the vertical motor driven '

cooling water pump breakers due to transfer switch failure; (6) loss of power to half of the cooling _ water header L isolation valves; and i

(7) failure of a single cooling water header isolation valvo, t The failure analysis demonstrated that no single failure can -

defeat the safety function of the cooling water system.

Specification 3.3.D.1.a is being revised to require that cooling water header isolation valves be prealigned and administratively controlled whenever the vertical motor driven cooling water pump is being used as a safeguards pump. This prealignment does not create the possibility of a new or different kind of avaident from thore previously evaluated since the prealignment places the cooling water header isolation valves in the positions required to i respond to analyzed events, i

- The addition of specification 3.3.D.1.d to clarify the minimum -

fuel sapply requirement for the diesel-driven cooling water pumps is considered administrative and as such does not create the possibility of a new or different kind of accident from any

_ previously evaluated.

The chango in_ specification 3.3.D.2.a.(2) to clarify Unit _1 ,

applicability is considered administrative and as such does not create the possibility of a new or different kind of accident from any previously evaluated. 1 The_ change in specification 3.3.D 2.a.(2) which clarifies that both paths from the transmission grid are to the unit rather than plant 4kV safeguards buses _is considered administrative and as t

4

( ahit>it A Page 32 of 37 the possibility of a new or dif ferent kind of such does not create accident from any previously evaluated.

dot % not For the reasons discussed above, the proposed amendment from create the possibility of a new or different kind of accident any accident previously evaluated.

involve a significant reduction in

3. The proposed amendment will not iht margin of safgly.

The upgraded cooling water system as reflected in the proposed Technical Specifications changes has the capacity to provide sufficient cooling in one unit during the injection and recirculation phnses of a postulated loss of coolant accident in a hot standby plus suf ficient cooling to maintain the second unit condition. With recpect to each of the diesel-driven cooling water pumps the t.pgraded vertical motor driven cooling water pumpand di provides an equivalent Upgrade of the water to engineered safety features equiprnent.

vert ical motor driven cooling water pump and supporting systems provides additional cooling water system reliability and, at am Prairic luland Nuclear water system as currently reflected in the Generating Plant Technical Specifications.

The addition of specification 3.3.D.I.d to clarify the minimum fuel supply requirement for the diesel-driven cooling water pumps is considered administrative and ar, such does not af fect the margin of safety.

to clarify Unit 1 Th* channo in specification 3.3.D.2.a.(2) applicability is considered administrative and as such does not affect the wargin of safety.

The change in specification 3.3.D.2.a.(2) which clarifies that both paths from the transmission grid are to the unit rather than nlant 4kV saleguards buses is considered administrative and as such does not affect the raargin of safety.

For the reasons discussed above, the proposed amendment does not involve a sign 11tcant reduction in the margin of safety.

and pursuant to 10 ';FR Part Based on the evaluation described above, 50, Section 50.91, Northern Stat es Power Company hasindetermined accordance that operation of the Prairie Island Nuclear Generating Plant involve any with the proposed License Amendment Request does not significant hazards considerations as defined by NRC regulations in 10 CPR part 50. Section 50.92.

- - - - - _ _ _ '~"%

e Eahlbit A Page 33 of 37

) b. Ischnical Snecification 4.5 Proposed Chances Revise specification 4.5. A.S.a to add a surveillance test requiring automatic start of the vertical motor driven cooling water pump at each refueling outago.

Add specification 4 $ B.1.c to require that the vertical mottr driven cooling water pump be operated at quarterly intervals. The specification is written to reflect that an acceptable level of performance shall be that the pump starts and reaches its required developed head and the control board Indications and visual observations indicate that the pump is operating properly for at least 1$ minutes.

Eta 12na_f.nr the PropostSt Chanru itse of the upgraded vertical motor driven cooling water pump as a safeguards pump requires a more stringent level of surveillance testing than currently required for this pwnp. The proposed additions to specifications 4.5.A and 4.5 B provide the more stringent level of surveillance testing corrsensurate with other engineered safety features testing.

$,nfety Evaluation and Dt1EIDdpation of Sirn{ficant Hazards CEDsiderations The proposed changes to the Operating Licenses have been evaluated to determine whether they constitute a significant hazards consideration as required by 10 CFR Part 50. Section $0.91 using the standards provided in Section $0.92. This analysis is provided below:

1. The proposed amendment will not involve a significant increase in the probability _or consequences of an accident previously evaluagg51 The cooling water system it. required to have the capacity and capability to provide sufficient cooling in one unit during the injection and recirculation phases of a postulated loss of coolant accident plus sufficient cooling to maintain the second unit in a hot standby condition, Cooling water system testing and surveillance demonstrate that the cooling water system is capable of performing its design function.

. Testing and surveillance for the upgraded vertical motor-driven

, cooling water pump is necessary to ensure its capacity and capability.

1

e tahlbit A l'on 54 of 37 Automatic start of the upgraded vertical n.otor driven cooling water puitp is being added to the cooling water syste:n test performed at ench refueling per spectilention 4.5.A.S.a.

Fur ther, the proposed change to specificat ion 4.S.11 requires the vertical motor driven cooling water pump to be touted or a quarterly basis.. This la consistent with ASME Section XI.

These additional test and surveillance requirements are equivalent to those performed for the other safety related portions of the couling water syst em.

For the reasons discussed above, the proposed amendment does not significantly incronac the probability or consequences of an accident previously evaluated.

2. The propoaed amendment will not. create the possibility of a new or 111LLttt.nLhhtLLn.f arIldent i ronuny nec1!snt i ..pleyjntsly_ evnhtolti._

Testing and surveillance proposed by these specification changen do not constitute new nodes of operation for the cooling water system and are equivalent to tests und surveillances performed on other saf ety-related portions of the cooling water system.

Therefore, the proposed amendment does tiot create the possibility of a new or different kind of_ accident from any accident.

previounty evaluated.

3. "lhe proposed araendment will not involve a significant reduction in Jhe margin of safety.

Testing and surveillance of the vertieni motor. driven cooling water piutp as specified in the proposed specification changes will .

provide assurance that the cool!ng watcr system will provide suf ficient cooling capability, Therefore, the proposed amendment does not involve a significant reduction in the margin of safety.

linsed on the evaluation described above, and pursuant to 10 GPR part 50, Section 50.91, Northern States power Comp ny han determined that operation of the prairie Island Nuclear Generating plant in accordance with the proposed 1.icense Amendment Request does not involve any significant har.ards considerations as defined by NRC regulations in 10 CFR part 50, Section 50.92.

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fahibit A 6 Pope 35 of 37 j Environmental Assespeni This license araendment requeat does not change effluent types or total effluent armounts nor does it involve an increrse in power 1cvel . Therefore.

this change will not result in any significant environmental impact.

4 1 1.

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.i COMPARISON OF REAL TIME PISC-BASED DIESIL t.ENERATOR AUTS AND CURRENT PLAuf IECHNICAL SPECIFICATIONS . ,.

j Diesel Generator (s)

- LMit 1 Core Damage Change in th!t 1 Real-Tim + Rick-Baced Real-Tirte Risk-Based Current ACT I31

l (Jnsysitable Fre m y (Per Yei.r)- CDF (Per Year) ACT (11 For Unit 1 ACT For Unit 2 (2J (Hours; i f, - -(Mours) (Noves)

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~I '9.B7E-06 0 -- -- --

1 Nons_(Base Case IPEH Results)

[

1.86E 8.70E-06' ' 481 [4* -- (51 168

[ D1 168 l D2 1.86E-05 -

8.70E-06 f.S2 !41 -- t5]

D5 1.02E-05 -4.02E-47 -- [5] 451 I4] 168 ,

i D6 1.02E-05 3.925-07 -- (51 482 (41 168 01, D2 2.58E-04 -2.73E-04 16' 237 2 t

01,_pS 2.1.0E-05 1 f.1E-05 311 _

311 Undetermined i li 01, 06 2.35E-05 1.37E-05 320 320 undetermined H l t

02, 05 - 2.36E-C3 1.37E-05 32"- 320 tjrceterminad D2, D6 2.376-05 1.41E-05 311 311 undetermined DS, 06 2.83E-05 1.25E-05 237 16 undeterinined (11 Allowed Outage Time ( A0T'

based on NUEEG/CR-5742 Er. 3.2; ACD

• ACT 5 5.GE-7 (rounded te the neerest whole hour).

(2) The IPEM study was : *Jnit 1 trudet fAlch applies to Unit 2 also (because the twa units are essentietty low.t!<st). Each dieset senerater provides priciary emergency power to its respactive unit and backup emergency power to the opposite unit. Therefore, the Unit 2 AOi 6 a Unit 1 primary diesel generator will be approximately count to the Unit 1 ACT of the trein-related Unit 1 backup dieset generator, etc. ,

131 Querent maxicos Acts based on T/S 3.7.9.1, . sad apply to both umts since D1 anJ D2 are shared by both units.

Cf.! . This A0T was reduced slightly to account fer this die $et's backup pnwer function for the oppesite unit (see (51).

[5] The catcatered ACT for this dieset with respect to the unit specified indicates that it ney be out of service for the entire year without increasing risk >

5.0E-07. The actual change in CDF for this dieset has been taken fr.to account by adding it to its 4CDF with respect to the unit to which it is dedicated, med ,

decreasing that ACT by the corresponding amount.

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