ML20076D910

Suppls 901023 Application for Amends to Licenses NPF-9 & NPF-17,respectively,in Response to NRC 910221 Request for Addl Info Re Proposed Request to Increase Allowable Temp of Standby Nuclear Svc Water Pond

ML20076D910
Person / Time
Site:	McGuire, Mcguire
Issue date:	07/18/1991
From:	Tuckman M DUKE POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20076D915	List: ML20076D910 ML20076D918
References
NUDOCS 9107310061
Download: ML20076D910 (9)

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i h:; iom V U . ?!I firC i U lI L~~1 NI DUKE POWER July 18,1991 U. S. Nuc!:ar Regulatory Commission Attention: Document Control Desk Washington, D. C. 20555

Subject:

McGuire Nuclear Station Docket Nos. 50-369 and 50-370 Proposed Technical Specifiution A ndment Supplement Increase Allowable Tempera'ure of L.ie Standby Nuclear Service Water Pond (SNSWP)

Response to Request for AdditionalInfctm' ion f Gentlemen:

By a letter dated February 21, 1991, the NRC staff requested additional information regarding their review of our proposed request to revise the required water temperature and monitoring elevation of the McGuire iSWP that was submitted by a Duke Power letter dated October 23,1990. Accordingly, please find 'ttached our response to the questions (Attachment 1).

l Please note in response to Question #2, after further evaluation of the proper elevation for j the temperature probe, 722 feet was determined to be the proper location instead of 718 l feet which was initially proposed. Since this new elevation of 722 feet affxts our initially preposed Technical *Specdications (TS) Amendment, we have included a new marked page reflecting the current desired changes to the TS (Attachment 2). This elevation change to 722 feet is more conservative and, therefore, does not significantly impact the Justification l and No Significant Hazards Analysis provided in our original TS submittal dated October 23,1990.

If you have any questions regarding our response or the amendment request, please contact David V. Ethington at (704) 373-2025.

l Very ly yours,

, ,. < g M. S. Tuckman, Vice President-Nuclear Operations g[j 9107310061 910718  :

PDR ADOCK 05000369 l P PDR

4 U.S. Nuclear Regulatory Commission Attention: Document Control Desk July 18,1991 Page 2 Attachments snswp.tse xc: (w/ Attachments)

S. D. Ebneter Regional Administrator, Region 11 Dayne Brown, Director Division of Radiation Protection T. A. Reed, ONRR P. K. Van Doorn Senior Resident inspector

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NITACH A1ENT 1 DUKE POWER COh1PANY hlCGUIRE NUCLEAR STATION HESPONSE TO REQUEST FOR ADDITIONAL. INFORh1ATION NRC OUESTIONJ Identify specifically what the applicable design basis inlet temperature assumptions are for those safety related aystems and components that credit the Standby Nuclear Service Water Pond (SNSWP) as a source of cooling or makeup water. If the design assumptions were changed to accommodate the higher SNSWP temperature of 82*F, provide applicable details.

DPC RESPONSC 1 As discussed in attachment 1 of the October 23, 1990 proposed technical speciGcation arnendment request, the SNSWP is the back-up source of water for the Nuclear Service Water (RN) system. In addition, the SNSWP is one part of the Ultimate Heat Sink for hicGuire, During abnormal or emergency operations, the SNSWP is the assured source of water for one train of the RN system

("B" essential Header). In the event that the Cowans Ford Dam is lost resulting in a loss of Lake Norman (i.e. seismic event), both trains of the RN System can be realigned to the SNSWP.

Additional details regarding the SNSWP and the RN system can be found in section 9.2.2 of the hicGuire FSAR.

As stated above, the SNSWP is the safety related source for the RN system and is the Ultimate Heat Sink. In turn, the RN System provides assured cooling water for various Auxiliary Building and Reactor Building heat exchanger during all phases of station operation. There are two redondant " essential headers" serving two trains of equipment necessary for safe shutdown.

The following is a list of safety related systems and components that, through the RN system, I take credit far the SNSWP; Component Cooling Pump hiotor Coolers Centrifugal Charging Pump hiotor Coolers Safety injection Pump hiotor Coolers Air Handling Fan Coil Unit (AHU) for the Containment Spray Pump hiotor l AHU for the Residual Heat Removal Pump hiotor

!- AHU for the Fuel Pool Cooling Pump hiotor l Nuclear Service Water Pump hiotor Coolers l Containment Spray Heat Exchangers L

Diesel Genciator Heat Exchangers Component Cooling Heat Exchangers ,

Centrifugal Charging Pump Bearing Oil Coolers Centrifugal Charging Pump Gear Oil Coolers Control Area Ventilation Systen. Condensers

Auxiliary Feedwater Pump hiotor Coolers Assured Auxdiary Feedwater Supply Assured Fuel Pool hiakeup Supply Assured Diesel Generator Cooling Water hiakeup Supp!y Assured Component Cooling Water hiakeup Supply Safety injection Pump llearing Oil Coolers The only systems and components impacted by the increase in the SNSWP Temperature are Containment Spray (NS) heat exchanger and Component Cooling (KC) heat exchanger All the other systems and coinponents identined above are not impacted by the proposed increase in water temperatore for the SNSWP. For those systems and components, the design basis inlet temperature assumption was that the temperature be maintained below 95*F, thus no changes to the design assumption to accommodate the higher temperature of 82"F is necessary.

As discussed in the October 23,1990 submittal, the impact of the higher inlet temperature on the NS, KC, and the ND heat exchangers was evaluated by re analyzing the contaimnent peak pressure analysis. The results of the analysis was provided by attachment 3 of the October 23, 1990 letter and additional information regarding the analysis is provided in our responses to questions 3 and 4

@C_OUESTIOBL2 Provide technicaljustification which supports the assumption that warmer water from elevations higher than 718 feet in the SNSWP will not be introduced as a result of the Gow dynamics involved.

DK_llE&ONSE 2 We have re-visited the calculations regarding the location of the SNSWP temperature probe and determined that a probe elevation (liL) of 722 feet will ensure that no signi6 cant volume of wate greater than 82 degrees F will be drawn into the intake during the Grst 12.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> of an accident. P! acing the probe at til 722 htSL provides 145 acre feet of cool water above the top of the intake opening at the start of the accident. During the Grst 12.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> of the accident ,

85 acre feet of water is drewn into tne plant. Therefore,12.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> into the accident there are 60 acre feet of " cool" (< 82* F) water remahling in the pond. This corresponds to the volume of water in the pond below IIL 713, providing 7.5 feet of cool water above the ir.take opening.

Since any warmer water in the pond will be more buoyant in proportion to its temperature, a substantial volume of warmer water will not be drawn into the intake within the 6rst 12.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> of an accident.

NilCMESTION 3 The information pertaining to peak containment pressure that sas provi&d in the amendment hpplicatior,is not consistent with the information contained in Section 6.2 of the Updated Final Safety Analysis Report. Provide clarification.

DE_I1ESLMSE2 Ilased on our review, the only actual diffe, in terms of input assumptions between the information sent and the u lated FSAR is the initial ice weight. The updated FSAR has the reduced ice weight of 1.89 x 1(f lbs. Please note that the NRC staff has reviewed and approved by a separate activity a technical speci0 cation amendment request regarding ISc ice Condenr:r reduced ice weight. 1 The other inconsistencies identined by our review, result from differences in format and from several errors found in the updated FSAR. The information provided with the amendment application is a copy of a Westinghouse package containing analytical results typically submitted to Duke Power to be used for updating the FSAR. Therefore, differences between these two documents in terms of information being presented are frequently found. The errors identined as a result of the review will be corrected for the 1991 update. The errors found are:

1) The RWST water temperature was modelled at 105T not 10(FF.

2) The containment structural heat sinks in table 6.2.1-17 of the FSAR are incorrect, the correct values are those transmitted with the initial Technical Specification Amendment request.

3) The iteat transfer coef6cient for the containment spray heat exchanger is 1.47 x 1 06 IITU/hr-T nct 2.94 x -10' IlTU/hr-T.

4) The Table 6.2.1 16 has not been updated. Th 'orrect table is attachcd.

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"Allit b.2.1 +16; P

'ICCS ANi] SPRAY ROW RA11IS ASSUMiILjN CON; AJNMl_NI 131Bijl {Al[UI.31 ION

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Interval ECCS fl0W 5 PRAY fl0W. ECCS l'l0W SPRAY llow . Auxiliary Spa.ny I fsec.)

free RWST from led L from Sume. from Si_me- Llow from simp 0'- 45 -0 0 0 0 0 4857 2

.45 -'1886.9- 3400 0 0- 0 i

'1887 -'2036.9 1064 3400 3793 0 0  !

r 2037 - 2999.9 0 3400 3917 0 0 'I

'3000 - 3319.9 0 3400 624 0 2400 i

3320 - 3499.9 0 'O 624 0 2400 3500 - End of 0. 0 624 3432 2400 .

Iransient-  ;

i I All flow rates'in g p

. ' lhis assumes 3793 gpa from:the Residual lleat Hemoval pump plus 603 gpa fros. the Safety injectson

',oump and 461 from the Centrifugal Charging-pump.  ;

IHeticculation-RilRllow .

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5 NRC OUESTIO.14 4 The input assumptions used in the peak containment pressure analysis have changed signiGcantly from those that were originally reviewed by the NRC. Provide the basis for each of the current .

l input assumptions, or reference licensing documents that have been submitted which explain the bases for these assumptions. Also explain why it was necessary to snake changes to those assumptions that have changed.

DPC RESPONSIL4 l

The input assumptions that have been changed from those originally submitted as part of the License Application for a Facility Operating License (FOL) are as follows:

l Initial ice mass l Nuclear Service Water temperature Containment strue' ural hea; sinks RWST water temperature Active sump volume Auxiliary spray flow from the sump Nuclear Service Water flow to the Containment Spray and to the Component Cooling heat exchanger Each of the above changes identified above were made in accordance with the provisions of 10CFR50.59. A brief discussion / explanation for each of the above changes are as follows:

Initial Ice Mass 1.89 x 10' lbs explanation:

Tbc basis for this change can be found in a proposed Technical SpeciGcation Amendment request that was submitted by a Duke letter dated June 7,1990. NRC approved the reduced ice weight amendment request on June 12, 1991.

Nuclear Service Water temperature 82"F explanation:

This input change is the subject of this amendment application,

m Containment structural heat sinks The new containment structural heat sinks was provided with the October 23, 1990 submittal.

ciphmatiefn The original structural heat sinks used for the McGuire model were signi6cantly different than the numbers used for the later Catawba model. Since the differences could not be justined, the structural heat tr:msfer areas were recalculated. As expected, the discrepancies were negligible, so that we now .ne the same structural heat sinks data for both plants.

Heat Exchanger heat transfer coefficients Containment Spray: 1,47 x 10^ BTU /hr- F CIchmatinin Due to fouling of the heat exchanger the original assumption for the heat transfer coefficient of 2.94 x 106 BTU /hr *F could not be met. The current v'lue was arrived at by engineering calculations and plant data.

Component cooling water neat exchanger: 1.60 x 106 BTU /hr- F c3plarlatiOE The tubes in the KC heat exchanger are exhibiting an increased tendency to pit and, therefore, additional tube plugging may be required in the near future. The current value of 1.6 x 10^

BTU /hr "F v.as arrived at by Westinghouse through a sensitivity study, by reducing the original l value of 5.0 x 10^ BTU /hr "F such thit the peak ontainment pressure remained below 14.8 psig RWST Water temperature l

105 F l CAphulatiotn l this input was originally 120'F. To gain margin to the containment design pressure, this temperature was later reduced. The current value is still conservative because the Technical Speci6 cation maximum is 10(TF.

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. Active sump volume -

90,000 ft' explanation:

The. Westinghouse model divides the sump into an active and inactive sump. The active sump is located within the crane wall and the inactive sump is located outside the crane wall. The excess water that spills into the inactive sump is no longer available for the safety injection or spray flow. At McGuire the suction piping for the recirculation flow was changed snd is now located outside the crane. wall. Therefore both sump regions can now be considered .'ctive.

This modification resulted in an increase from the original volume of 46,000 ft' to the curent value.

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- Auxiliary spray now from the sump 2400 gpm explanation:

This input was increased from originally 1,623 gpm in order to achieve a safety margin. The new value is based on an engineerir.g calculation.

Nticlear Service Water now to the contalp'nent spray and to the component cooling heat i exchanger

. 3,800 gpm/5,500 gpm h exolanation The original flows of 5,000 gpm/8,000 gpm could not be met. Plant data and engineering calculations required a reduction of the flow rates' for both heat exchanger.

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