ML20198H475
| ML20198H475 | |
| Person / Time | |
|---|---|
| Site: | Hope Creek  |
| Issue date: | 12/30/1997 |
| From: | Eric Simpson Public Service Enterprise Group |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-97-04, GL-97-4, LR-N97792, NUDOCS 9801130309 | |
| Download: ML20198H475 (8) | |
Text
{{#Wiki_filter:. e Pubhc Serv 6ce Doctre and Gas - Ccrnpany E. C. Simpson Public Serwce Electrc and Gas Company P.O. Box ?*a Hancocks Bridge PAJ 08038 009 3341700 c., P,-. "-* DEC 8 01997 LR-N97792-United States Nuclear Regulatory Commission Document Control Desk . Washington, DC 20555 Gentlemen: 90 DAY RESPONSE TO GENERIC LETTER 97-04 ASSURANCE OF SUFFICIENT NET POSITIVE SUCTION HEAD (NPSH) FOR EMERGENCY CORE COOLING (ECCS) AND CONTAINMENT HEAT REMOVAL PUMPS HOPE CREEK GENERATING STATION FACILITY OPERATING LICERSE NO. NPF-57 DOCKET NO. 50-354 This letter provides the 90 day response to Generic Letter 97-04 for the Hope Creek Generating Station, As requested in Generic Letter 97-04, Public Service Electric and Gas Company (PSE&G), via Attachment 1 to this letter, is providing:
- 1) the general methodology used to calculate the head loss assoc}ated wit.h Emergency Core Cooling System (ECCS) suction' strainers; 2) the required and available Net Positive Suction Head (NPSH) for the ECCS pumps; 3) a description of any differences between the design-basis NPSH analysis and the most recent analysis reviewed t
and approved by the NRC for which a safety evaluation was issued; and 4) information concerning containment overpressure in the NPSH analyses, Should you_have any questions or comments on this transmittal, do not hesitate to contact us, Sincerely 7 o f.h Attachment 1 Affidavit-9801130309 9719.30 yDR ADOCK 05000354~ PDR" ll ll I.l!!,'I' ll I.ll.l l.l o) -- ( fhW Papw
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y t-.., m t :. - -~ i ? a .1 4 + . f" Document - Control:: Desk;. y u lLR-N97792f'l LC-l Mr.f HJ 'J. Milleri,i Administratori-;-Region'-'I L U '. ; S.1-- Nuclear'RegulatoryLCommission-1475.Allendale' Road. ' - +- --Kingi of i Prussia,s _PAi19405 :. iMs. B; Mozafari, Licensing. Proj et:t Mknager s Hope; Creek : '10.;S. Nuclear Regulatory Commission .One White Flint. North _:11555.Rockville. Pike ~ -MailiStop:14E21 Rockville, MD 20852 j Mr.-S.-Morris-USNRC: Senior Resident Inspector (X24)_ Mr.I-Ki Tosch, Manager IV ' Bureau of Nuclear Engineering PO Box:-415 =. Trenton, NJ. 08625 i [I i i 6! E 1 1 ,'j.. m 3 .H s a 7 j
r:. e -REF:-LR-N97792 STATE OF NEW JERSEY ) ) SS. COUNTY OF SALEM ) E..C. Simpson, being. duly sworn according to law deposes and says: !I am Senior Vice President - Nuclear Engineering of Public ' rvice Electric and Gas Company, and as such, I find the matters set forth in the above referenced letter, concerning the Hope Creek Generating Station, are true to the best of my knowledge, information and belief, Subscribed and Sworn to before me this d day o 1& n}/ A, 1997 Q ~\\i c' T U7(I A. 13 30L -hotary Puhlic bf dew Jersey y kiMBERLY JO BROWN NOTARY NtRtiC 0F NEW JERSEY ="an n p 21 m -My Commission expires on ________j
9 O LR-N97792 Response to Generic Letter 97-04 90 DAY RESPONSE TO GENERIC LETTER 97-04 ASSURANCE OF SU1'FICIENT NET POSITIVE SUCTION HEAD FOR EMERGENCY CORE COOLING AND CONTAINMENT HEAT REMOVAL PUMPS 1. Specify the general methodology used to calculate the head as associated with the ECCS suction strainers. The general methodology used at Hope Creek to calculate the head loss associated with the ECCS suction strainers is as follows: The asic equation for calculating NPSH is: - NPSH = h. - h,p. + hn hr where: absolute pressure on the surface of the liquid supply h. = level. head corresponding to the vapor pressure of the liquid h w. at the temperature being pumped. static height that the liquid supply level is above or he = below the pump centerline of the impeller eye, suction line losses including entrance losses and hr = friction losses. Additional detail on each of the terms is provided below, h. absolute pressure on the surface of the liquid supply = level. For both CS (Core Spray) anc RHR (Residual Heat Removal) 14.7 psia is used in the calculations, h head corresponding to the vapor pressure of the liquid = w. at the temperature being pumped. This term requires the determination of.the temperature of the fluid being pumped. The temperature used in the limiting net positive suction head (NPSH) calculation is based on the post-LOCA maximum fluid temperature predicted. UFSAR Table 6.2-6 1 of 5
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1 j vt cAttachment'if LR-H97792 ?hasponselto::GenericlLetter 97-04? \\ - shows(a pea'kl suppre'ssion^ pool 1temperaturef of,212*F.:. The NPSH - : calculations 7use; a Jvapc.rEpressure..of - 14.-7 psia,o corresponding 'to 3 a temperature 4of1212*F. j m static height-tha_tLt!he liquid ; supply level-isc above or: ch,E = . belowLthe;pumpicenterline:orJthe impeller: eye.. 3 i This-cterm is-the minimum static-height 1of. fluid _above the pump reference point'. For-RHR,'thefpump reference point.is 2 feet: j Tabove5the topiofithe; pump _mountingLflange. This corresponds 4 tota-i ireactor building elevation of-~60.-29 feet, as shown-in'UFSAR f, sectior._6.3.2.".4,_ page 6.3-29. The minimum fluid height'infthet j suppression pool"is defined-in Technical Specification--3.5.3.a-J f" Suppression Chamber", as an indicated-level of 74.5 inches. (This level corresponds to a1 reactor building elevation-of ~ <71 feet-1/2 inch. (71.04 is used in calculation BC-0002 (Q),s while- -UFSAR section 6.3.2.2.4; rounds to 71 feet). RHR static head =isLas follows: 171.04 - 60.29 = 10.75 feet 1 ForfCS the pump reference point is the pump suction:line'at Ji reactor: building elevationLof 55 feet 7 inches. The minimum fluid'heightLin the suppression pool-is the same as for RHR - -{ feet-1/2. inch. CS static head is as follows: 71.04 - 55.58 = 15.46 feet suct1on line losses including-entrance losses and he= = friction lossos. The following parameters are considered in the NPSH calculations:
- Fluid velocity --The-maximum expected. flow: rates are 4015 gpm for.
each'CS. pump and 10,500 gpm for,each RHRLpump. The_ internal pipe diameter is used to convert the volumetric flow rate to velocity. i Pipe-roughness.- Two methodologies are used to calculate pipe 1 roughness... 'Reynolds : numbers (Re)Jand friction factors.(f)are 9Gaerated using equations'fromicrane1Co.,-Technical' Paper-410, " Flow *of Fluids". 6. .s F 2 of'5-3 'Y~-- l 3_,.. I I' . +. - e ,,-.<-,;-..,,-e w.,-, w. -a
o LR-N97792 Response to Generic Letter 97-04 / The alternate methodology uses the Saph and Schoder formula ho = 0.296 to 0. 4 69 v '" " /d'd6 2 where, v equals velocity in feet per second and d equals inside diameter of the pipe, in feet. The low values cf the constant and exponent apply to smooth pipes and the high values to rough pipes. The NPSH calculations use the formula in the following formt ho = 0. 38v""/d 2d$ The resultant friction factors are as follows: Crane 410 Saph and Schoder CS 6.0128 0.0175 ~ RHR 0.0110 0.0155 The friction factors resulting from the Saph and Schoder formula, are used in the head loss calculations and provide margin towards the aging effects of the piping. Length of piping - System isometric drawings were used to tabulate the length and diameter of the piping. Number and types of valves and fittings - The system isometric drawir. were used to determine the number and type of valves and fittin;,. Crane Co., Technical Paper 410, " Flow of Fluids" was used to convert the valves and fjttings to equivalent piping lengths to determine the overal.1 friction head loss. Strainer losses
- llope Creek is installing large, stacked disk strainers in responce to Bulletin 96-03.
ahe RHR pump "D" strainer was replaced during refuel outage 1, in November 2997. The remaining strainers are scheduled for replacement during refuel outage 8, which is currently scheduled to begin in February 1999. NI'SH available data is provided below, in Item 2, for the existing strainers as well as the replacement stacked disc atrainers. The NPSH available with the existing strainers is calculated using_the original vendor provided design ~ basis of 1.0 foot head loss at 50% plugged. Pre-operational startup testing of the CS and RilR systems was performed with the strainers 50% blocked. Pressure drop across the strainers was not measured, however, the flow rates were measured and the test criteria was met for availa' ole NPSH with the strainers 50% blocked. 3 of 5
o LR-H97792 Resp 6nse'to Generio Letter 97-04 The NPSH available with the replacement < strainers is calculated using a debris loading and head. loss determined as described in the Hope Creek response to Bulletin 96-03. t 2. Identify the required NP8H and.the available NPSH. Existing Strainers Required NPSH (feet of water) Available NPSH CS 10 11.2 RilR 4.5 6.02 Replacement Strainera e Required NPSH (feet of water) Available NPSH CS 10 10.28 RHR 4.5 4.99 As discussed in Item 1 above, The NPSH available with the i i existing strainers is calculated using the original design basis of 1.0 foot head loss at 50% pitc;ed. The NPSH available with the replacement strainers is calculated using debris loading and head loss methodologies described in the Hope Creek response to Bulletin 96-03. 3. Specify whether-the curraat design-basis NP8F analysis differs from the most recent analysis reviewed and approved by the NRC for which a safety evaluation was issued. The current design basis is reflected in calculations BE-0001(Q), . revision 3, for CS and BC-0001(Q), revision 2, for RHR. These calculations were _ approved (by PSE&G) in 1984. The most recent analysis; reviewed and approved by the NRC for which a safety evaluation-was issued is shown in UFSAR section 6.3.2.2.3 for CS and section_6.3.2.2.4 for-RHR. =These sections were unchanged -from;revisionLO-of the-UFSAR, dated April 1988, until installation of'the new' strainer design. For the "old" strainer design,tthe current design: basis analysis does not differ from the most recent analysis reviewed and approved by the NRC for which a. safety evaluation.was issued. The new analysis and UFSAR 4 of 5 rf ppP++-ec -9 e ;b7+r +-m-ig 9 y-9 te---- T --s 'ny-q +~*wy
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t i I LR-H97792 Resphnee'to Generic Letter 97-04 sections associated with the new strainer design is being incorporated into. Hope Creek's licensing and design bases as described in Hope Creek's response to NRC Bulletin 96-03 and the associated NRC Safety Evaluation dated October 31, 1997 (TAC NO. M96150). 4. Specify.whether containment overpressure (i.e., containment f pressure above the vapor pressure of the sump or suppression, pool fluid) was credited in the calculation of available i NPdH. Specify the amount of overpressure.needed and the j minimum overpressure available. The suppression pool fluid is assumed to be at a temperature of 212*F. ine corresponding vapor pressure cf 14.7 psia was used in j the calculations. Therefore, containment overpressure was not credited in-the calculation of NPSH. 5. When containment overpressure :is credited in the calculation i of the available NPSH, confirm that an appropriate l containment pressure analysis was done to establish the i minimum containment pressure. l Containment overpressure is not credited in calculations of available NPSH at Hope Creek. i I t S i 5 of 5 4 , - - -..... _ _ _ _. ~... --}}