ML20059N067

Proposed Tech Specs Re Addition of 161 Kv Offsite Source

ML20059N067
Person / Time
Site:	Cooper
Issue date:	09/28/1990
From:	OMAHA PUBLIC POWER DISTRICT
To:
Shared Package
ML20059N065	List: ML20059N067 NLS9000310, Application for Amend to License DPR-46,consisting of Tech Spec Change 83,including Addl/Independent Offsite Power Source
References
NUDOCS 9010100007
Download: ML20059N067 (9)

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, 1 REVISED TECHNICAL SPECIFICATION PAGES FOR-ADDITION OF THE 161 KV CFF-SITE SOURCE

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193 BACKCROUND/ DISCUSSION In 1981, . the Nebraska Public Power District. (DISTRICT) ; installed' a 101- kV r 'tchyard at Cooper Nuclear Station (CNS). This 161 kV switchyard'isidesigned in a ring bus configuration capable of handling _ three -(3) line terminals. . These-t.hree (3) line terminals consist of 1) Omaha Public Power District's :(OPPD) 161 kV transmission line to Auburn, Nebraska; 2) tie-in to the existing 345/161 kV auto-transformer located in the CNS 345 kV switchyard.and; 3)_ tie-in to the CNS startup station service transformer (this configuration can'be seen in Figure -

1). To date, the DISTRICT has not' taken credit for this 161 kV transmis'sion line 3

as an off site power source for Cooper Nuclear Station.

With the installation of the 161 kV switchyard, the DISTRICT has the capability of supplying power to the startup station service transformer f?:om one of two off-site sources; 1) the 345/161 kV auto-transformer which is fed from the 345 kV -

I switchyard and; 2) .the 161 kV switchyard -(this configuration can be seen in Figure 2). Although the 161 kV switchyard has been in operation since 1981, the-l 9010100007 900928' PDR ADOCK 05000298

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[ DISTRICT has never1 acknowledged or requested thtt this off-site source be it.cluded in our operating license (CNS Technical Specifications) . - In ' the - .!

y unlikely - event Cooper. Nuclear Station would have lost the' entire 345 : kV .

switchyard (resulting in the emergency buses'1F-and 1G being powered from the .;

emergency transformer orf the diesel generator),- the DISTRICT could have supplied <

-i power to the-startup transformer;through the 161 kV System. However, the CNS ;l Technical Specifications,fas currently _ written,.do not acknowledge the ability to energize the startup station service transformer from the'161 kV swit'chyard sys tem.- CNS Technical Specifications -currently state in part "both off-site '

sources (345 kV and 69 kV) are available~."-

Therefore, the DISTRICT proposes to revise CNS Technical' Specification 3.'9. A.1.a' ,

to include the OPPD 161 kV system as an off-site power source available to Cooper ; ,

1 Nuclear Station to power the auxiliary electrical' equipment. Technical Specification 3.9. A.1 a will be revised to read as follows: -(revision underlined) f "One off-site source (345 kV or 161 kV) and the emerrency off-site source (69 kV) and the startup transformer and emergency transformer are available and capable of automatically supplying power to the 4160 Volt emergency buses 1F and 1G. 1 This proposed change will allow Cooper Nuclear Station to energize the startup-station service transformer from the 161 kV switchyard, thereby increasing- the operational readiness of off-site AC power sources for Cooper Nuclear Station.

This proposed change will also establish a greater flexibility in off-site power source availability at CNS. With approval of this proposed change, the DISTRICT

NLS9000310 '

Attachmint-Page 3 of 9 will-have three-(3) separate,_ independent, and unique off site power sources L _ entering Cooper Nuclear Station: 1) 345 kV source This source currently has-t four (4) 345 kV iines entering 'the -345 kV ' switchyard which are available. to supply power to emergency buses 1F and 1G; 2) 161 kV source. - This source currently has : one (1) 161 kV line entering the 161 kV switchyard which is -

available to supply power to emergency buses IF and 1G; 3)-69 kV source This-is -

, a stand-alone source and is directly tied into the 69 kV emergency transformer-l' . . ,

and is used to supply power to emergency buses IF.and'10.  !

The 161 kV transmission line discussed in this proposed change as an alternate ,

off site power source for Cooper ~ Nuclear Station, was designed and has been analyzed to show, that this line will- provide adequate rated voltage . to the 4

emergency buses under all accident scenarios -(including worst - case LOCA). In-

. addition, the voltage on this transmission line is continually monitored, with the meter readout provided in the control room for. the operator's information.

Also, procedures are in place, and annunciation is provided to declare this transmission line inoperable in the event that the transmission line voltage -

drops below the required voltage necessary to operate all loads on the emergency ,

buses.

l It should be noted that these three- (3) independent sources are' adequately separated, and that the loss of one (1) off-site source, would not disable the two (2) remaining off-site sources. Therefore, with the approval of. this proposed change, the DISTRICT will be well positioned to cope with industry concerns involving station black out and loss of off-site power due to the I

existing independence and diversity of Cooper Nuclear Stations off-site source capability / availability.

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Page 4 Eof 9: 3 The DISTRICT requests an approved SER on this proposed change byl June 1991. This

- will enable the DISTRICT to proceed, as scheduled, with a planned 345 kV, -

Switchyard-Modification, - This' modification is necessary to accommodate a new. j

- line terminal enterinj; the 345' kV switchyard in association with the Missouri,' l

' Iowa, Nebraska Transmission (MINT) Project. , h t

' EVALUATION OF THIS REVISION WITH RESPECT TO 10CFR50.92 l

This license amendment proposes to add a.new 161 kV off-site power source.

I 4 The enclosed Technical Specification change is judged to involve no significant- l

. 'i hazards based on the following: '

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1. Does the proposed license amendment involve a significant increaae -in' the O probability or consequence of an accident previously evaluated?

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Evaluation l

-i ll The proposed amendment would revise the Technical Specifications to recognize an y additional existing source of off-site power, available 'to supply the emergency- I buses. Thic additional full capacity, independent source - of off-site power '

significantly improves the reliability and flexibility of . the Cooper Nuclear-St.: tion auxiliary electrical system. The probability of a loss-of voltage:or- l.

degraded voltage to the station emergency buses is si 5 nificantly reduced. The  ;

proposed amendment will require the availability of at least one off-site source  ;

prior to allowing reactor criticality. In addition the 69 kV emergency line till still be required to be operational as currently specified in the existing a o.

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, . l Therefore, = this change .has- no-. effect fon : the

-Technical Specifications.

probability of loss of off-site power or reliability of the power supply to plant emergency buses and equipment, and there.is no increase in the probability or the .i consequences of an analyzed' accident.

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2. -Does the propose'd licensed amendment create the possibility of a new or different kind of accident from any accident previously evaluated?. ,

Evaluation-1

-The proposed Technical Specification change deals exclusively with the off-site ,

electrical power sources for the Cooper Nuclear Station. This groposed change reflects the addition of a full -' capacity.. independent . off-sive source of .

electrical power to the plant. Cooper Nuclear: Station is designed' to respond to r

design basis accidents assuming the , coincident .' loss : of ' off-site power, and.

I analyses contained in Section XIV of the Updated Safety Analysis Report (USAR)..

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reflect this assumption, e

l The intent of the~ additional full capacity, independent off-site source is to )

. improve the reliability of off-site power. No new or different kind of accident l.

l from any accident previously evaluated would be created since the - loss of' l

l off-site power is already assumed. 1 l

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3. . Does the proposed amendment involve' ~a significant reduction'in the margin

, of safety?

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The proposed Technical Specification wording. change will recognize lthe addition

_to the plant of another full capacity,1 independent, source of off-site electrical power. This source wi11'significantly~ improve the reliability and availability ; -]

of off-site power sources capable of supplying power to the emergency. buses.  !

However, Cooper Nuclear Station is designed to respond to design basis ' accidents assuming a coincident loss of all off-site power. Therefore,' this proposed I

change will not involve a reduction in the margin of safety. .,

i As previously described, the Technical Specification change reflects the addition.

of the 161 kV electrical source which will provide < an additional - source of ,

off site power available to the plant. The installation process for the AC power source involved standard industry practices related to transmission system l 1

equipment. The overall effect of the change is' to : improve plant safety. -

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. FIGURE -I rog,7 or 9 161: KV J SWITCHYARD L CO NN ECTIONS- ?a i

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-TIED TO CNS 34SKV SWITCHYARD

(' 34S KV/164 KV AUTO-TRANSFORMER .

3 ( LOCATED IN 345 KV SWITCHYARD.

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) CNS' OFF-SITE SOURCE CONNECTIONS:

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,(.G .N LIMITING-CONDITIONS FOR' OPERATION SURVEILLANCE REOUIREMENTS.

3.9 AUXILIARY ELECTRICAL SYSTEM- 4.9. AUXILIARY ELECTRICAL SYSTEM

.Aoulicability:

6EPJicabilitv: f

-1 Applies to the auxiliary electrica1H-L ' Applies to the periodic . testing power. system. requirements- of. the auxiliary ,

eleetrical. systems.

l Obiective: Obiective:

To assure - an adequate' supply of Verify the operability o'f .the electrical power for operation of auxiliary electrical' system. 'J those systems required for' safety.

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Soecification: Soecification:

A. Auxiliarv Electrical Eculement A. Auxiliary Electrical Eautoment .

1. The reactor shall not be. made 1. Emergency Buses Undervoltage' Relaysi critical from a Cold Shutdown' Condition- unless 'all of the ,,

g , og voltage relays- 1 following conditions are satisfied:

a. One off-sitei source (345 kV or once every 18 mon &s, loss of a 161 kV) and the emergency off-site voltage--on emergency buses is source (69 kV) and the' startup simulated to demonst. rate the  !

transformer- and emergency load shedding fromE emergency ,

transformer are available and . buses and the automatic start capable of automatically supplying of diesel generators.

power to ' the 4160 Volt emergency buses IF and 10. 'b' . Undervoltage relays L

b. Both diesel generators shall be' 'Once every 18 . months, low I operable and there shall be a voltage' on emergency buses is minimum of 45,000 gal. of diesel simulated- co- demonstrate fuel in the fuel oil storage tanks. disconnection.of the emergency ,

buses from the offsite power

c. The 4160V critical buses 1F and 1G source.. The undervoltage-and the 480V critical buses IF~and relays.-shall. be calibrated 10 are energized. once,every 18 months.

1. The loss of voltage relays 2. Diesel Generators and their auxiliary relays I are operable, a. Each diesel-generator shall be

2. The undervoltage relays and- not less ' than 50% of rated-their auxiliary relays are load for no less than 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />  ;

operable, '

once each month to demonstrate P*#"" "" #*" "****

d. 'The four unit 125V/250V batteries and their chargers shall be operable.

e. The power monitoring system for the inservice RPS MG set or alternate source shall be operable.

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