ML20041D238
| ML20041D238 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 02/17/1982 |
| From: | Nelson C Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8203040612 | |
| Download: ML20041D238 (10) | |
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FEB 171932 A
LICENSEE: Maine Yankee Atomic Power Company FACILITY: Maine Yankee Atomic Power Station h
SUBJECT:
MEETING
SUMMARY
- MAINE YANKEE CONTAINMENT SUMP PERFOR The subject of containment sump performance is being reviewed generically by the staff as Unresolved Safety Issue A-43.
Based on preliminary reports (Ref.1) done for this review we became concerned that the amounts of mineral wool insulation at Maine Yankee, which might become debris due to a LOCA, could block the containment sump screen and affect ECCS performance. On February 2,1982, we and our consultants met with members of the Maine Yankee Atomic Power Company (MYAPC) to discuss the potential for and effects of insulation debris on the containment sump screens.- A list of attendees is attached as Enclosure 1.
MYAPC discussed its present plans regarding this issue:
As depicted in Enclosure 2 MYAPC plans to install screens in shield wall penetrations through which water would flow enroute tothesumpduringthepostulatedLO(A.
Currently these screens are designed to stop large (relative to the mineral wool fiber size) pieces of insulation and may be installed during a March 1982 outage.
During that outage MYAPC plans to conduct a detailed review of the types and locations of insulation within containment.
In addition, MYAPC will provide insulation samples for the NRC study of -' pressure drops due to blockage by insulation' scheduled for this spring. outlines the MYAPC questions regarding the preliminary USI-A-43 report. Specific point's were highlighted by MYAPC as follows:
The maximum amount of debris mineral wool insulatio'n has been overestimated due to the assumption that the safety injection l
tanks are insulated which MYAPC believes is not the case.
l The assumption that 100% of the mineral wool insulation which becomes debris will do so as fiber-size mat.erial is too con-servative. We referenced data from tests done in Finland (Ref. 2&3) to support this assumption while acknowledging that these tests may not represent debris generated by high energy fluid impact from all angles.
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. The assumption that 100% of mineral wool fiber debris will be transported to the sump screens is too conservative. We indicated that this assumption was made in the absence of information on the migration characteristics of mineral wool fibers in water.
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MYAPC stated that it would proceed with its plans, discussed above, as well as review the practicality of:
1.
replacing insulation in key areas; 2.
modifying the design of the shield wall screens such that they would block fiber putsagc; and 3.
testing to obtain; information on: th'e g_eneration and.' trans--
port of mineral wool fibers.
I We agreedwith MYAPC's course of action and stated that we would attempt l
to test for mineral wool fiber transport and screen deposition characteristics during the testing to be performed this Spring.
It was also agreed that MYAPC would tell us the porosity (open or closed) l of the ca":cium silicate insulation used at Maine Yankee.
Ocir;nd hd by:
Christian C. Nelson, Project Manager Operating Reactors Branch #3 Division of Licensing
References:
See attached list cc; See next page l
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NUCLEAR REGULATORY COMMISSION h,,
WASHINGTON, D. C. 20555
- t, +....,g FEB 171982 LICENSEE: Maine Yankee Atomic Power Company FACILITY: Maine Yankee Atomic Power Station
SUBJECT:
MEETING
SUMMARY
- MAINE YANKEE CONTAINMENT SUMP PERFORMANCE The subject of containment sump performance is being reviewed generically by the staff as Unresolved Safety Issue A-43.
Based on preliminary reports (Ref.1) done for this review we became concerned that the amounts of mineral wool insulation at Maine Yankee, which might become debris due to a LOCA, could block the containment sump screen and affect ECCS performance. On February 2,1982, we and our consultants met with members of the Maine Yankee Atomic Power Company (MYAPC) to discuss the potential for and effects of insulation debris on the containment sump screens. A list of attendees is attached as Enclosure 1 MYAPC discussed its present plans regarding this issue:
As depidted in Encicsure 2 MYAPC plans to install screens in shield wall penetrations through which water would flow enroute to the sump during the postulated LOCA. Currently these screens are designed to stop large (relat'ive to the mineral wool fiber size) pieces of insulacion and may be installed during a March 1982 outage.
During that outage MYAPC plans to conduct a detailed review of the types and locations of insulation within containment.
In addition, MYAPC will provide insulation samples for tha NRC study of ' pressure drops due to blockage by insulation' scheduled for this spring. outlines the MYAPC questions regarding the preliminary USI-A-43 report. Specific point's were highlighted by MYAPC as follows:
The maximum amount of debris mineral wool insulation has been overestimated due to the assumption that t!ie safety injection tanks are insulated which MYAPC believes is not the case.
i The assumption that 100% of the mineral wool insulation which becomes debris will do so as fiber-size material is too con-servative.
We referenced data from tests done in Finland (Ref. 2&3) to support this assumption while acknowledging that these tests may not represent debris generated by high energy fluid impact from all angles.
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. The assumption that 100% of mineral wool fiber debris will be transported to the sump screens is too conservative. We -indicated that this assumption was made in the absence of information on the migration characteristics of mineral wool fibers in water.
MYAPC stated that it would proceed with its plans, discussed above, as well as review the practicality of:
1 replacing insulation in key areas; 2.
modifying the design of the shield wall screens such that they would block fiber passage; and 3.
testing to obtain. information on the generation and trans--
port of mineral wool fibers.
We agreedwith MYAPC's course of action and stated that we would attempt to test for mineral wool fiber transport and screen deposition characteristics during the testing to be performed this Spring.
It was also agreed that MYAPC would tell us the porosity (open or closed) of the calcium silicate insulation used at Maine Yankee.
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W Christian C. Nelson, Project Manager Operating Reactors Branch #3 Division of Licensing
References:
See attached list cc; See next page
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MEETING
SUMMARY
DISTRIBUTION Licensee: Maine Yankee Atomic Power Company
- Copies also sent tc those people on service (cc) list for subject plant (s).
Docket File NRC PDR.,
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ORB #3 Rdg JHeltemes BGrimes RAClark Project f.danager PMKreutzer
'0 ELD I&E ACRS-10 ORB #3 Summary File NRC Participants t
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Maine Yankee Atomic Power Company cc:
E. W. Thurlow, President Mrs. L. Patricia Doyle, Presid:nt Maine Yankee Atomic Power Company SAFE POWER FOR MAINE Edison Drive Post Office Box 774 Augusta, Maina 04336 Camden, Maine 04843 Mr. Donald E. Vandenburgh First Selectman of Wiscasset Vice President - Engineering Municipal Buf1 ding Yankee Atomic Electric Company U. S. Route 1 20 Turnpike Road Wiscasset, Maine 04578 Westboro, Massachusetts 01581 John A. Ritsher, Esquire Atomic Safety and Licensing Board Ropes & Gray U.S. Nuclear Regulatory Commission 225 Franklin Street Washington, D. C.
20555 Boston, Massachusetts 02110 David Santee Miller, Esq.
Mr. Rufus E. Brown 213 Morgan Street, N. W.
Deputy Attorney General Washington, D. C.
20001 State of Maine Augusta, Maine 04330 Mr. Paul Swetland Resident Inspector / Maine Yankee Mr. Nicholas Barth c/o U.S.N.R.C.
Executive Director P. O. Box E Sheepscot Valley Conservation Wiscasset, Maine 04578 Association, Inc.
P. O. Box 125 Mr. Charles B. Brinkman Alan, Maine 04535 Manager - Washington Nuclear Operations Combustion Engineering Inc.
Wiscasset Public Library Association 4853 Cordell Avenue, Suite A-1 High Street Bethesda, Maryland 20014 Wiscasset, Maine 04578 Mr. Robert H. Grace Mr. Torbet H. Macdonald, Jr.
Senior Engineer - Licensing Office of Energy Resources Maine Yankee Atomic Power Company State House Station #53 1671 Worcester Road Augusta, Maine 04333 Framingham, Massachusetts 01701 Robert M. Lazo, Esq., Chairman Atomic Safety and Licensing Board U.S. Environmental Protection Agency U.S. Nuclear Regulatory Commission Region I Office Washington, D. C.
20555 ATTN: Regional Radiation Representative JFK Federal Building Dr. Cadet H. Hand, Jr., Director Boston, Massachusetts 02203 Bodega Marine Laboratory University of California Bodega Bay, California 94923 Mr. E. C. Wood, Plant Manager Maine Yankee Atomic Power Company State Planning Officer P. 0. Box 3270 Executive Department Wiscasset, Maine 04578 189 State Street Augusta, Maine 04330 Regional Administrator Nuclear Regulatory Commission, Region I Office of Inspection and Enforcenent 631 Park Avenue King of Prussia, Pennsylvania 19406
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References:
t 1.
Burns & Roe Preliminary Draft Report, " Methodology for Evaluation of Insulation Debris", including Appendices for Salem Unit No.1, ANO-2 and Maine Yankee, October 16,1981 (prepared under contract toSandiaLabs).
2.
"Loviisa Emergency Cooling System Model Tests", Translated from the Finnish Report No. 275, 8/76 3.
"Model Tests of the Screen Meshes of the Emergency Cooling System",
Translated from the Einnish Report No. 291, 4/80 1
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ATTENDEES Name Organization G. Requa USNRC 00L Al Serkiz USNRC DST Edward J. Gahan Burns & Roe Peter Strom Sandia John Wysocki Burns & Roe Ronald Reyer Burns & Roe John Garrity Maine Yankee J. McCumber Maine Yankee Jukka Laaksonen USNRC RSB Frank Orr NRC, RSB Robert H. Groce Maine Yankee Chris Nelson NRC i
David Shum CSB/DSI Jack Kudrick CSB/DSI/NRC R. Clark NRC/0RB#3 T. Novak NRC/ADOR t
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s REACTOR CONTAINMENT PLAN ELEV.
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- 0" PROPOSED SCREEN LOCATIONS
u Enclosur.e 3 -
QUESTIONABLE AREAS IN SANDIA REPORT 1.
Quantity of Insulation Involved A.
Need specifics of piping / equipment involved.
B.
Some mineral wool blankets have been replaced.
2.
Mechanisms of Insulation Release A.
Need basis of assumption that insulation between break and hinge point will be released.
B.
Need basis of assumption that 5 banded sections of insulation are released on impact.
C.
What is f ailure mechanism for jet impingement.
3.
Degree of Insulation Breakage A.
Strength of insulation jacket; Will it break open?
B.
Finnish testing utilized high pressure jets to pulverize insulation - what is correlation to 0.5 psia stagnat. ion pressure.
4.
Amount of Insulation Which will Migrate to Sump A.
Need Basis for Assumption that 100% of blanket insulation will migrate when Finnish testing showed only 20-30%.
B.
Some percentage of insulation will be snagged by obstructions or f all to areas of floor with stagnant flow conditions and not migrate.
.