ML20249B836
| ML20249B836 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 06/19/1998 |
| From: | Terry C, Woodlan D TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-97-04, GL-97-4, TAC-M99976, TAC-M99977, TXX-98155, NUDOCS 9806240294 | |
| Download: ML20249B836 (4) | |
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""""l Log # TXX-98155 L
C File # 10035 C
C Ref. # 10CFR50.54(f) 1UELECTRIC GL 97-04 C. Lance Terry June 19,1998 s,ador vic, vi,,ie,
& PrincipalNuclear Officer U. S. Nuclear Repjulatory Commission Attn: Document Control Desk Washington, DC 20555
SUBJECT:
COMANCHE PEAK STEAM ELECTRIC STATION (CPSES)
DOCKET NOS. 50-445 AND 50-446 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING GL 97-04 ISSUES AT COMANCHE PEAK, UNITS 1 AND 2 TAC NOS. M99976 AND M99977 REF: 1) TU Electric Letter, logged TXX-98004, " Response to Generic Letter 97-04,.
. " from C. L. Terry to U.S. Nuclear Regulatory Commission dated January 14,1998.
- 2) TU Electric Letter, inqged TXX-98096, Response to Generic Letter 97-04,...
" from C. L. Terry i MS. Nuclear Regulatory Commission dated April 14, I
1998.
- 3) NRC Letter from T. J. Polich to C. L. Terry dated May 22,1998.
Gentlemen:
On October 7,1997, the NRC issued Genwic Letter 97-04," Assurance of Sufficient Net Positive Suction Head for Emergency Core Cooling and Containment Heat Removal Pumps."
included in this letter was a request for a 90 day response from all addressees. TU Electric provided that response on January 14,1998, per Reference 1. In Reference 2, TU Electric provided confirmation that the response included as an attachment to Reference 1 was I
accurate and complete for CPSES. On May 22,1998, the NRC issued a Request for Additional Information (Reference 3) to CPSES. That requested information is provided in tlie I
attachment to this letter.
This communication contains no new licensing basis commitments regarding CPSES Units 1 and 2.
!f you have any questions, please contact Randy Blankenship at (2f4) 897-5890.
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P PDR COMANCHE PEAK STEAM El ECTRIC STATION P.O. Box 1062 C,len Rose. Texas 76N3-1002 E
TXX-9$155 Page 2 of 2 Sincerely, C. L. Terry By:
D. R. Woodlan Docket Licensing Manager RTB/rb Attachment c-
. E. W. Merschoff, Region IV
. J. l. Tapia, Region IV T. J. Polich, NRR Resident inspectors, CPSES I
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Attach (nent to TXX-98155
'Page 1 of 2 CPSES RESPONSES TO REQUEST FOR ADDITIONAL INFORMATION REGARDING GL 97-04 AT COMANCHE PEAK, UNITS 1 AND 2 TAC NOS. M99976 AND M99977 1.
What is the maximum sump temperature assumed in the Net Positive Suction Head (NPSH) analysis?
The maximum sump temperature used in the NPSH analysis is the saturation temperature. Since this temperature varies as the containment pressure varies, no specific figure was used for the sump temperature in the NPSH analyses. This is explained below.
The NPSH, equation is defined as follows:
P' ~ P* + Z - H, NPSHA =
Where:
p, =
The absolute pressure on the free surface of the liquid (Ib,/ft2) p, = Vapor pressure of pumped liquid at design temperature (Ib /ft')
f y=
Specific weight of the liquid (Ib / ft')
f 2=
The vertical distance from minimum water surface to the pump impeller centerline (ft)
H, =
The head loss due to the friction in the pipe (ft)
To be consistent with regulatory guide 1.1 the pressure on the surface is set equal to the vapor pressure of the pumped liquid and the first term drops out. This action sets the temperature of the Ilquid at the surface to be at saturated conditions. (i.e. at the onset of boiling at the temperature that corresponds to the varying containment pressure).
Therefore, the equation is reduced to:
NPSHA = Z-H, Of these two terms, the friction loss (H,) is the only term where an indirect temperature was used in the NPSH Calculations. This is because the specific weight and/or the A
viscosity was used to determine the friction losses.
For the containment spray A/E NPSH calculations, the specific weight used was 61.71 lb /ft' which corresponds to a fluid temperature of 120 *F. For the RHR NPSH f
. calculations, the specific weight used was 59.8 lb,/ ft' and the viscosity used was 0.29 centipoise which corresponds to an approximate fluid temperature of 212 F.
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' Attachment to TXX-98155 Page 2 of 2 l
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~ 2.
Your response to question 2 in a letter dated January 14,1998, provides the results of the NPSH analyses provided by the NSSS vendor and NE. The A/E NPSH analyses l
appear to be more limiting. Which NPSH analysis is the calculation of record for Comanche Peak, Units 1 and 2 The NPSH analysis performed by the A/E is the NPSH calculation of record for CPSES for NPSH ayailable. The analysis performed by the NSSS vendor as part of 1
the recirr 'ation orifice sizing was performed to ensure an adequate limitation of pump runout to support NPSH reauired and was, therefore, included for completeness. Both analyses are considered within the design and licensing basis of CPSES. Any plant modifications or reanalyses performed at CPSES, consider both the NSSS vendor and A/E analyses for completeness.
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