ML20215C275
| ML20215C275 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 12/05/1986 |
| From: | Gridley R TENNESSEE VALLEY AUTHORITY |
| To: | Youngblood B Office of Nuclear Reactor Regulation |
| References | |
| TVA-SQN-TS-73, NUDOCS 8612150086 | |
| Download: ML20215C275 (5) | |
Text
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- TENNESSEE VALLEY. AUTHORITY.
CHATTANOOGA, TENNESSEE 374ot
' SN 157B Lookout Place DEC 0 5 986 TVA-SQN-TS-73 Director.of Nuclear Reactor Regulation Attention: ' Mr. B. Youngblood, Project Director PWR' Project Directorate No. 4
. Division of Pressurized Water Reactors (PWR)
Licensing A U.S. Nuclear Regulatory Commission Washington, D.C.
'20555
Dear Mr. Youngblood:
In the Matter of
)
Docket Nos. 50-327 Tennessee Valley Authority
)
50-328 SEQUOYAH NUCLEAR PLANT (SQN) - TECHNICAL SPECIFICATION CHANGE 73 Our August 8, 1986 submittal (TVA-SQN-TS-73) requested an' amendment to operating licenses DPR-77 and DPR-79 to change the technical specifications of Sequoyah Nuclear Plant units 1 and 2.
The proposed change reduces minimum flow rate requirements for the Safety Injection Pumps (SIPS) and Centrifugal Charging Pumps (CCPs). On October 22, 1986, J. Holonich and W. Jensen of your staff requested additional'information concerning not positive suction head (NPSH) available to the SIPS versus NPSH required for two specific operating conditions.
In accordance with 10 CFR 50.90, enclosed are 40 copies of the response, as provided by Westinghouse Electric Corporation to NRC's request for additional information.
If you have any questions, please call T. S. Andreychek at 615/870-7470.
Very truly yours,
[-
TENNESSEE VALLEY AUTHORITY 7
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ridley, D ector Nuclear Safety and Licensing s
Sworn to-and subscri before me this #
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1986 111 01 L
' Notary Public My Commission Expires i
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An Equal Opportunity Employer
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..- Directo'r of Nuclear Reactor Regulation DEC 0 5' E06 cc-(Enclosure):
U.S. Nuclear Regulatory Commission Region II
- Attn:
Dr. J. Nelson Grace, Regional Administrator 101 Marietta Street, NW, Guite 2900 Atlanta, Georgia 30323-Mr. Michael H. Mobley, Director (w/o-Enclosures)
Division of-Radiological Health T.E.R.R.A. Building 150 9th Avenue North Nashville. Tennessee 37203 Mr. Carl Stahle Sequoyah Project Manager U.S. Nuclear Regulatory Commission-
-7920 Norfolk Avenue Bethesda, Maryland 20814.
Mr. G. G. Zech Director,-TVA Projects U. S. Nuclear Regulatory Commission Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 1
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November 13, 1986 e
Mr. H. L. Abercrombie b
Ref: W GO#CO-41805 9
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Tennessee Valley Authority Sequoyah Units 1 and 2
-E Safety Injection Pumo NPSH Available
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Dear Mr. Abercromble:
TVA Sequoyah Nuclear Station, per M. J. Burzynski, requested Westinghouse to
-;;m-provide the NPSH available for the operation of the High Head Safety Injection (SI) Pump NPSH in the following operating modes:
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1.
The SI Pump NPSH available when taking suction from the RWST.
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Note: At the end of the injection from the RWST.
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The SI Pump NPSH available during cold leg recirculation.
gj The responses are as follows:
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Question:
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The NPSH available at the end of the injection for the SI pump when d
drawing suction from the RWST.
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Response
1g Per Westinghouse calculation, the recuired NPSH (per pump vendor performance 2
curve) is 27 feet at 650 gpm.
The TVA layout from the TWST provt jei-Eh--
E available of 54 feet which is sufficlewnt available NPSH for the SI rRumpAPLMT 3
This NPSH available will be also sufficient for the SI Pump at 675TphF4fFcFiTAFF requires an NPSH of 38 feet (Reference Ltr. TVA-86-510).
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TVA-86-718 Mr. H. L. Abercromble November 13, 1986-Question:
2.
The NPSH available for the.SI Pump during cold leg recirculation.
Response
Westinghouse performed Hot / Cold Leg recirculation calculations evaluating the.
NPSH available for the SI Pumps.
Extrapolating information_from the calculations demonstrates that adequate NPSH is available to the suction of the SI Pump to satisfy the NPSH requirement of 38 feet at 675 gpm.
The adequacy of the Safety Injection Pump NPSH available during cold leg recirculation was based on information extrapolated from the hot leg recirculation calculation.
The Safety Injection Pump flowrate will be greater during cold leg recirculation than during hot leg recirculation due to the setting of the cold leg injection path needle valves to limit the runout of the pump to 675 gpm.
The results of the Westinghouse hot leg recirculation calculation concluded that the NPSH Available was 25 feet for the SI Pump at a flowrate of 525 gpm (per pump vendor curve NPSH required is 19 feet) with the RHR Pump providing suction boost.
This calculation was performed with one RHR Pump operating at a flowrate of 4700 gpm with a pump head of 317 feet.
During cold leg recirculation one RHR Pump provides:
1.
900 gpm to the Centrifugal Charging Pumps 2.
675 gpm to the SI Pump (to maximize NPSH required only one SI pump delivers to all four cold legs) 3.
2400 gpm to the RHR flow path down two cold legs Therefore the total RHR Pump flowrate is 3975 gpm at a pump head of 350 feet.
The increase in RHR Pump head (350 ft. -317 ft.) of 33 feet increases the Available NPSH (25 ft. + 33 ft.) to 58 feet which is greater than the SI Pump Required NPSH of 38 feet at 675 gpm.
Very truly yours, NGHOUSE ELECTRIC CORPORATION a ua saw L. L. Williams, Manager ESSO Projects Mid South Area D. F. Oudek/05025.0378.0 cc:
H. B. Abercrombie R. C. Weir D. H. H11 son R. U. Mathieson I. R. Williamson T. S. Andreychek 6723e