ML17326A486
| ML17326A486 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 01/28/1980 |
| From: | Dolan J INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML17326A472 | List: |
| References | |
| AEP:NRC:00355, AEP:NRC:355, NUDOCS 8002060050 | |
| Download: ML17326A486 (6) | |
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REGULATORY ORHATION DISTRIBUTION SY M (RIDS) 8002060050 DOC ~ DATE! 80/01/28 NOTARIZED'O DOCKET Donald C.
Cook Nuclear Power'Pianti'nit 1g Indiana 8
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AFFILIATION'ffice of Nuclear Reactor Regulation
SUBJECT:
Forwards final rept re'ecirculation sump under LOCA/jet fmpingement" conditions completing response to NRC '7808O1 request fot addi info,Jets from credible breaks 7n AC8 will not c'ause significant ai'r binding of'CC'S pumps performances
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INDIANA Pa MICHIGAN ELECTRIC COMPANY P. O. BOX 18 BOWLING GREEN STATION NEW YORK, N. Y. 10004 January 28,1980 AEP:NRC:00355 Donald C.
Cook Nuclea1'lant Unit Nos.
1 and 2
Docket Nos.
50-315 and 50-316 License Nos.
Subject:
Request for addi'tional Information Regarding Recirculati'on Sump Mr. Harold R. Denton, Di'rector Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commi'ssi'on Washington, D.C. 20555
Dear Mr. Denton:
This letter completes our response to a Request for Additional Information enclosed iTI Mr. A. Schwencer's letter of August 1, 1979 concerning the performance of the D.
C.
Cook Plant recirculation sump under LOCA/jet i'mpi'ngement conditions.
In our letter of September 24, 1979 (AEP:NRC:00260) we stated that the tinal report of our.jet'impingement testing program would be submitted to you along with replies to the specific concerns identified in the referenced Request for Additional Information.
The final report entitled, "Experimental Investigation of Air En-trainment at a,Reactor Containment Sump Due to Break and Drain Flows Donald C.
Cook Nuclear Plant," prepared by Alden Research Laboratory (ARL) is enclosed as Attachment A to this letter.*
- 30 additional copies will be sent under separate cover.
'he report concludes that neither. submerged nor unsubmerged jets from credible breaks in the Reactor Coolant System (RCS) will cause significant air binding or other degradation of'ECCS pumps performance.
The report further concludes that drain flow from the ice'condenser generates. air entrainment at the impact location; however, most of bubbles are not drawn into the sump under the crane wall.
Small quantities of relatively smaller bubbles are pulled down the upstream sump portion into the downstream area, and most of these collect at the top cover in the downstream portion.
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Mr. Harold R. Denton, Di'rector AEP:NRC:00355 bubbles accumulate and occasionally a slug. of air is drawn into the suction pipe.
The report concludes that it would be beneficial to modify the two drains in questi'on, to eliminate the drain flow--
jet impact i'n front of the sump.
It must be pointed out that the entire ice condenser drai'n flow testing was performed assuming a
water level in the contai'nment of 602'10".
This water level is extremely conservati've since it does not account for the approximately 1,000,000 lbs. of water from the ice condenser drains prior to switchover of the fi'rst ECCS train.
Accounting for this quantity of water the revi'sed level would be approximately 607'.
Noting the effect of water level on bubble entrainment, the revised water level will eliminate or si'gnificantly mitigate this problem.
AEPSC requested that ARL perform testing at higher water levels to confirm that ice condenser drain flow does not cause air entrainment at a water level of approximately 607 feet.
These tests will be com-pleted within approximately two weeks of this submittal.
If the re-sults indicate that the problem has been eliminated, no further action will be taken.
If the tests indicate that the problem persists we will review implementation of the modifications outlined in the subject report.
In addition to the sump model testing we have evaluated the potential structural effects of break flow jets on the sump and have found that jets from credible RCS breaks do not compromise the sump's structural integrity.
JED:em Very truly yours, F.
John E. Dolan Vice President cc:
R.
C., Callen G. Charnoff R.
S.
Hunter R.
W. Jurgensen D. V. Shaller-Bridgman
ATTACHMENT A TO AEP:NRC:00355