PY-CEI-NRR-1329, Suppls 890417 Response Re Station Blackout Consisting of 4 H Coping Evaluation & Proposed Plant/Procedure Mods,Per NUMARC 87-00 & Reg Guide 1.155

Suppls 890417 Response Re Station Blackout Consisting of 4 H Coping Evaluation & Proposed Plant/Procedure Mods,Per NUMARC 87-00 & Reg Guide 1.155

ML20070L691
Person / Time
Site:	Perry
Issue date:	03/15/1991
From:	Lyster M CENTERIOR ENERGY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
RTR-REGGD-01.155, RTR-REGGD-1.155 PY-CEI-NRR-1329, NUDOCS 9103200164
Download: ML20070L691 (4)

Text

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GNTE PERRY NUCLEAR POWER PLANT Malt Aasess:

P.O BOX 07 Michael D. Lyster 10 CENTER ROAD PERRY, OHIO 44081 PERRY, OHIO 44081 VICE PRESIDENT NUCLEAR

<2'6) 2543737 March 15, 1991 PY-CEI/NRR 1329 L U.S. Nuclear Regulatory Commission Document Control Desk Washington, D. C. 20555 Perry Nuclear Power Plant Docket No. 50-440 Supplemental Response on Station Blackout Gentlemen:

By letter PY-CEI/NRR-0995 L, dated 4/17/89 we provided a 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> blackout coping evaluation and proposed plant / procedure modifications for NRC review.

This evaluation was based on NUMARC 87-00 and Regulatory Guide 1.155, with implementation of proposed changes to be 1 year following NRC notification that our evaluation was adequate.- We-subsequently reconfirmed that our '

evaluation was performed in accordance with NUMARC 87-00, and that diesel generator target reliability of~0.95 would be maintained, in letter PY-CEI/NRR-1159L, dated 3/30/90.

In a telephone conference on 2/8/91, several additional NRC questior.s l concerning our blackout evaluation were addressed. These questions and the responses are included in the attachment to this letter. These answers should provide the necessary information to all.ow NRC resolution of this issue for l the Perry Nuclear Power Plant.

If you have any questions, please feel f rr.e to call.

Sincer 1 ,

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l Attach:cnt PY-CEI/NRR-1329 L Page 1 of 3 l

1) Explain the classification of PNPP as severe weather (SV) group 2 versus .

SV group 3 since, according to the PNPP UliAR, there is only one I right-of-way for the first 1.1 miles from the plant.

Severe Weather Group vas calculated per iable 6 of Regulatory cuide 1.155, using the multiplier on annual tornado 2xpectation (b) = 12.5. This (b) factor is justified by the ansver to qtestion number 22 in " Responses to Questions Raised at the Station Blackott S*.minars," which was approved as Enclosure 2f in NRC letter dated 10/7/88, dApproval of NUMARC Documents on Station Blackout," A.C. Thadani to V.H. Rasin (NUMARC). As stated there, a plant is justified using a (b) factor of 12.5 if transmission' lines-are separated at least 1/4 mile at a point less than 1 mile from the plant.

Referring to Perry USAR Pigure 8.2-1, line S-29-AT-ERV.is in the common corridor for a radial distance of 4600 ft, from the switchyard (distance verified by survey or. 2/15/91), before doubling back-in the dircetion of the plant and heading east to obtain the required separation within 1 mile of the switchyard. USAR text (p. 8.2-7) vill be revised accordingly.

2a) Does the condensate storage tank technical specification level of 150,000 gallons apply under normal operating conditions?

The condensate storage tank (CST) is a 500,M0 gallon tank vented to atmosphere. Normal level of the condensate torage tank is automatically maintained between 250,000 and 300,000 gallons. Redundant level alarms warn the operator if CST level drops belov 155,000 gallons available to a common suction for High Pressure Core Spray (HPCS) and Reactor Core Isolation Cooling (RCIC) The HPCS/RCIC common-suction line taps into the tank approximately-one foot ( 15,000 gallons) from bottom. Other supply lines that penetrate the CST and drop below the 11 foot level have siphon breaker holes to prevent siphoning the HPCS/RCIC reserve volume. CST low level switches that automatically transfer HPCS/RCIC suction from the CST to Suppression Pool are covered by Technical Specification 3.3.3-1, ECCS Actuation Instrumentation.

At least 150,000 gallons therefore remain available for HPCS supply.

2b) Please provide information on Leveral key points of the sequence of events during SBO, including the conditions of the reactor coozant system ,

(RCS) at the end of the SB0 event.

Initial conditions for the 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> coping analysis, and important points cf the sequence of events are listed belov, including RCS conditions at the end of the SB0 events l Time Plant Conditions 0 - see Initial Conditions: USAR Table 15.0-1 Loss of all AC transmission lines, plant undervoltage relays initiate diesel starts for Div. 1, 2, 3 0 + set. USAR 15.2.6.2.2; HPCS diesel start 10 see Div. 1 and 2 diesels fail to reach design conditions 13 see HPCS diesel at design conditions; HPCS AC power available

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.- l LAttachznt:

=PY-CEI/NRR-1329 L Page 2 of 3 i Time _ Plant Conditions 36 see HPCS initiates on Level 2 90 min Manual depressurization initiated per EPG guidancel I suppression pool at 143 F.

140 min CST volume depleted; trar.sfer (automatic or manual) HPCS pump suction to suppression pool.

0 173 min Suppression pool 180 Fi-manually initiate upper pool dump by' opening suppression pool _make-up system valves 182 min Upper pool dump complete; suppression pool 163'F ,

240 min Suppression pool-180 F1 reactor outlet 160 psia saturated.

stese -

240 + min Division 1 or 2 AC:pover-restored manuallyLestablish. normal decay host removal and commence suppression _ pool cooldown:

2c) What are the plant modifications necessary to make the Suppression Pool Make-up System (SPMS) available?

As noted in our original response, a temporary power s'upply to Lthe SPMS valves from the Division 3 AC source vill be utilise 4. _ This consists of a temporary

~

cable used to: interconnect spare buckets _between HPCS motor control center.-

EF1E-1 and motor control center EF1C07, which- vill allow:the necessary valve manipulations to be made from t he control" room. Battery-powered lighting vill.

also be provided. The use of the' temporary cable. vill-'be proceduralised.and the cable vill be ste nd.in a designated location'.

3). Bettery calculations: What actions. vill be taken to ensure that~the

, Division 1 or-2 batteries (guidance requires thatiat'least one division L of instrumentation and control be available) vill-last for four. hours, since'the UEsR states that the batteries are designed.for two hours?-

As described and found accepOble in'SER (NUREG-0887) Section 8.3.2.1 and in SSER 10 Section 16.2.15, maintenance tie busses connect the same Divisions of Unit 1 and 2, e.g., Unit 1,? Division 1 to Unit 2, Division 1._ This cross-tie effectively doubles the-capacity of our DC sys' tem, providing:the 4 hour-capability described. These cross-ties'are routinely.used:in normal _ plant operations for maintenance.- - As noted in the SER,- battery capacity includes a design margin-of 1.15 and an aging factor of-1.25-_-No _ Unit 1-load shedding was assumed.in determining the capability to supply DC'pover to associated safe shutdown loads for 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.

Our station blackout (SBO) procedures vill;specify that plant DC loadsivill remain on=the Division / Unit batteries in'use at the time.of SB0 initiation. '

Unit 2 batteries vill be tied to their c~orresponding Unit 1 Division by SBO.'

procedure early in the event, before loss of capability.to supply necessary ,

loads.

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AttachDDnt i PY-CEI/NRR-1329 L

Page 3 of 3 l

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4) Loss of HVAC. Explain a) the way in which areas of concern vere chosen, b) the initial temperature assumptions and final temperatures reached.

Areas of concern vere chosen using NUMARC B7-00 for guidance, with areas necessary to support HPCS operation, and to provide control roorn indication / control functions, receiving primary attention. As noted in NUMARC 87-00, large dry containments are well bounded by LOCA (SAR Chapter 15) temperatures used to determine equipment qualification envelows. The Perry Mark III containment, although not as large as comparably sized PVR's, has over one million cubic feet of free volume and significant temperature increases are not expected during sn SBO.- Ve have also reviewed dryvell temperature response, with 66 gpm teakage assumed due to both recirculation pump seals and Tech Spec maximum leakage, which confirmed that other USAR analyzed accidents conservatively bound the SB0 dryvell conditions.

The steam tunnel does not contain equipment required for 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> coping.

'<entilacion for HPCS-associated equipment is provided by a system povered from the HPCS diesel, with the exception of some co;tainment instrumentation (addressed above) and the switchgear/ battery room. This room temperature is routinelycheckedonplantrounds,agdremainsatorbelov75F. Heatup under SB0 conditions vould be less than 13 F, which is of no equipment qualification (EO) concern, since the lovest temperature effect on eguipment in this room is MCC thermal overload *"2tch potential actuation at 104 F. In addition, this room would be n ,a for the MCC interconnection described under #2c, coincidentally providing further cooling from a much larger svitchgear room with no SB0 heat lod (ennpting MOV isolation if needed, one valve at a time).

TheControlRoom,algowithdailytemperaturerecordsindicatinginitial temperaturebelov75F,wascalculatedugingNUMARC87-00methodologyto increase 23 F under SB0 conditions to 98 F.. Starting at the Tech Spec 4.7.2 limit of 90 F resulte in a final temperature of 113 F. -Instrument cabinets (each of which contains associated DC inverters) vill be opened under procedural control if temperatures exceed 104 F to provide assurance that no EQ concern exists.

The redundant reactivity control system invu ..rs located in the cable spre. ding room vill be turned of f per SB0 procedures in order to essentially eliminste heat loads in this area.  !

6) What are the plant modifications necessary to provide containment isolation capability during an SB07 The plant modification described in #2c vill allow closure of required inboard isolation-MOV's from the control _ room with position indication. Procedures a vill list the isolation valves to be closed, one at a time to avoid f overloading the temporary cable or the AC power source. This procedure vill address normally closed M0V's to ensure that they are closed. Credit vill be taken for normal function of inboard isolation check valves. l I