ML20245H285
| ML20245H285 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 08/04/1989 |
| From: | Tucker H DUKE POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737, TASK-2.D.1, TASK-TM TAC-65753, TAC-65754, NUDOCS 8908160398 | |
| Download: ML20245H285 (3) | |
Text
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,a DUKE PowEn GOMPm P.O. DOX 33189 e
CHARLOTTE, N.O. 28242
- !!AL IL TUCKER Truenown N" ::l"ln,,
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- 4 August 4, 1989 Document Control Desk U. S. Nuclear Regulatory Commission Washington, D. C.
20555
Subject:
Catawba Nuclear Station, Units 1 and 2 Docket Nos. 50-413 and 50-414 Performance Testing of Relief and Safety Valves Gentlemen:
Dr. K. N. Jabbour's letter dated October 18, 1988 transmitted a request for additional information regarding the performance testing of relief and
. safety valves (NUREG-0737, Item II.D.1). These questions were based on my submittals dated April 29, May 31, and June 14, 1988. Please find attached a response to Question No. 2 from your request for additional information.
Responses to Question Nos. 1, 3, and 5 were transmitted to the NRC per my March 16, 1989 letter to the Document Control Desk. We are preparing a plan of action regarding Question No. 4 and will provide the details by August 16, 1989. We are currently reviewing vendor proposals regarding the thermo-hydraulic analysis to determine the methodology for resolving the items in Question No. 4. The enclosed response to Question No. 2 was scheduled for submittal to the NRC on July 31, 1989. We apologize for the slight delay.
Very truly yours,
/
H.
. Tucker JGT/4/IID1 xc:
Mr. S. D. Ebneter Regional Administrator, Region II U. S. Nuclear Regulatory Commission 101 Marietta St., NW, Suite 2900 Atlanta. Georgia 30323 g(,
Mr. W. T. Orders NRC Resident Inspector Catawba Nuclear Station g g
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8908160398 890804 PDR ADOCK 0500 3;
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' Question 2 DPC's response to question 6 in Reference 1 stated that the bending moments
-calculated for the safety valves and PORVs did not include a seismic load because the probability of a peak seismic load coinciding with a peak blowdown load was extremely small.
This response is not considered acceptable because the NRC request specifically asked that the loads due to a safe shutdown earthquake (SSE) be included in the bending moment calculation.
Therefore, provide a comparison of the bending moment calculated for Catawba 1 and 2 including the loads due to deadweight, thermal expansion, SSE, and valve actuation.
Compare the calculated bending moment to those applied to the valves in the EPRI test program.
If the calculated bending moment is higher than the applied moment, justify the valves will operate satisfactorily with the higher bending moment.
Response
Unit 1 SAFETY VALVES:
(Dresser 31749A)
COMPARISON OF C-E TEST VALVE MOMENTS TO PLANT SPECIFIC ANALYSIS EPRI TEST ANALYSIS Lateral Moment Maximum Lateral Moment (in-lbs)
(in-lbs)
Test Number:
1011 Valve Outlet:
241,738 135,709 POWER OPERATED RELIEF VALVES i
1.
Control Components l
EPRI TEST ANALYSIS l
Lateral Moment Maximum Lateral Moment (in-lbs)
(in-lbs)
Test Number:
47-CC-3S Valve Outlet:
39,000 39,482 L
- - o. -...., -
...a Unit 2 SAFETY VALVES:
(Dresser 31749A)
COMPARISON OF C-E TEST VALVE MOMENTS TO PLANT SPECIFIC ANALYSIS
'EPRI TEST
' ANALYSIS Lateral' Moment Maximum Lateral Moment (in-lbs)
(in-lbs)
Test Number:
1011
' Valve Outlet:
241,738 137,897 POWER OPERATED RELIEF VALVES 1.
Control-Components EPRI TEST ANALYSIS Lateral Moment Maximum Lateral Moment (in-lbs).
(in-lbs)
Test Number:
'47-CC-3S Valve Outlet:
39,000 38,811 NOTES:
(1) Homents are perpendicular to the plane of pipe configuration.
(2) Maximum lateral moment is the vectorial resultant of the two orthogonal l
moments. : Load combination is gravity + thermal + SSE + peak blowdown.
(3) The power operated relief valve, INC36B, is the only valve exceeding the EPRI test moment. Valve 1NC36B exceeds the EPRI test moment by only 1%.
l The difference between 39,482 and the EPRI test value of 39,000 is insignificant.
A review of the test parameters shows that the EPRI bending moment is based on maintaining pipe stresses at.75 Sy.
The 39,487 in-lb moment for valve 1NC36B would cause pipe stresses at.76 Sy, which is still a considerable margin below yield.
Combining SSE with L
peak blowdown is conservative because the probability of peak seismic l
loads occurring simultaneously with peak blowdown load is extremely small. The duration of the blowdown is very short.
Combining SSE with peak blowdown is.not.part of the Catawba design basis for piping analysis.
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