ML20213D728
| ML20213D728 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 05/18/1981 |
| From: | Rubenstein L Office of Nuclear Reactor Regulation |
| To: | Tedesco R Office of Nuclear Reactor Regulation |
| References | |
| CON-WNP-0359, CON-WNP-359 NUDOCS 8106020147 | |
| Download: ML20213D728 (4) | |
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MEMORANDUM FOR:
R. Tedesco, Assistant Director for Licensing DL FROM:
L. Rubenstein, Assistant Director for Core and Containment Systems, DSI
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION RE: WNP-2 SRV METHOD-6 LOGY During the ACPS subcommittee meeting that was held in San Francisco on April 28 and 29, 1981, regarding Mark II pool (ynamic loads, representatives of WNP-2 re-quested a separate discussion with F. Eltawila of our staff regarding their SRV improved methodology.
The enclosed request for additional infomation reflects the staff's positions and need for additional infomation that were stated during the meeting with the applicant's representative, during the separate meeting cited above.
It should be forwarded to the UNP-2 applicant promptly to confim the results of the meet-ing.
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Lester S. Rubenstein, Assistant Director for Core and Containment Systems Division of Systems Integration
Enclosure:
As stated cc:
R. Mattson
. W. Butler A. Schwencer R. Auluck J. Kudrick F. Eltawila
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Contact:
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e Request for Additional Infonnation 1
Containment Systems Branch 021.SRV.12 Provide detailed calculations of the wall pressure amplitude multiplier to account for the difference between WNP-2 design conditions and Caorso test conditions.
021.SRV.13 Provide the quencher submergence and SRV line volumes for all WNP-2 discharge lines.
021.SRV.14 Detailed quencher design and vacuum breaker characteristics are important in the determination of SRV air clearing load.
Due to the difference in detailed quencher design and vacuum breaker characteristics between Caorso and WNP-2, we require further justification of t' e applicability of Caorso data to WNP-2 or h
require in-plant test.
021.SRV.15 Our evaluation of the Caorso data reveals that higher wall pres-sure amplitudes are observed for consecutive SRV actuation tests for lines with two 10" vacuum breakers than those with only one vacuum breaker.
Since the WNP-2 design utilizes two 10" vacuum breakers on each SRV line, it is our position that pressure am-plitude multipliers which will account for this difference should be provided.
021.SRV.16 Our evaluation of the Caorso data indicates that higher pressure amplitudes are observed for multiple SRV actuation tests than sin-gle SRV first actuation tests. Since WNP-2 specifications are based on single SRV actuation test results, it is our position that a pressure amplitude multiplier for the all-valve case based on the DFFR correlation (assuming WNP-2 surface area) should be used.
ENCLOSURE
. 021.SRV.17 The vertical wall pressure distribution in the WNP-2 specifica-tion does not bound Caorso test results.
Since the accuracy of sensors used to obtain test data is questionable, it is our posi-tion that the staff generic acceptance criteria set forth in NUREG-0487, Supplement 2. Item II.B.4.d should be used.
021.SRV.18 The method used in the calculation of the circumferential pres-sure distribution in the WNP-2 asymmetric case may not be con-servative because' of an over-prediction of pressure on the oppo-site side of the pool of the discharging quencher (s).
It is our recommendation that zero dynamic pressure be specified for the 180' circumference on the opposite side of operating quenchers to assure a maximum overturning moment.
021.SRV.19 The use of the DFFR correlation in the calculation of pressure multipliers to account for differences in parameter values between the WNP-2 design condition and Caorso test conditions is not neces-sarily conservative.
Over-prediction of pressure amplitude corresponding to the Caorso test conditions by the DFFR correlation may lead to under-predic-tion of the pressure multiplier.
Furthermore, despite the overall conservatism in the DFFR correlation, trends with respect to indi-vidual parameters may not be conservative, e.g., trend with re-spect to SRV steam flow.
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. It is, therefore, our position that trends obtainable from Caorso test results, if more conservative than the DFFR corre-lation, should be used in the pressure multiplier calculations or incorporation of the Caorso data in the DFFR mooel should be provided for our review.
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