ML20043B077
| ML20043B077 | |
| Person / Time | |
|---|---|
| Issue date: | 04/26/1990 |
| From: | Remick NRC COMMISSION (OCM) |
| To: | Chilk S NRC OFFICE OF THE SECRETARY (SECY) |
| References | |
| NUDOCS 9005240154 | |
| Download: ML20043B077 (2) | |
Text
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- N0TATION o
3,,3 I TO:
SAMUEL J. CHIUC, SECRETARY OF THE COMISSION FROM:
C0094ISSIONER REMICK
SUBJECT:
SECY-90-120 - REC 0l#4ENDATIONS OF CONTAll#4ENT PERFORMANCE IMPROVEMENT PROGRAM FOR PLANTS WITH MARK II, MARK III, ICE CONDENSER, AND DRY CONTAINMENTS APPROVED X
,,,. J DISAPPROVED ABSTAIN NOT PARTICIPATING REQUEST DISCUSSION C0684ENTS:
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DATE r
WITHHOLD VOTE
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ph ENTERED ON "AS" YES /
bk NO 9005240154 900426 bbRE ON E PDC
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,o DRAFT TO:
ALL LICENSEES HOLDING OPERATING LICENSES AND CONSTRUCTION PERMITS FOR NUCLEAR POWER REACTOR FACILITIES
SUBJECT:
CollPLETION CF CONTAINMENT PERFORMANCE IMPROVEMENT PROGRAM AND FORWARDING OF INSIGHTS FOR USE IN THE INDIVIDUAL PLANT EXAMINATION FOR SEVERE ACCIDENT VULNERABILITIES - GENERIC LETTER NO. 88 20,.
SUPPLEMENT NO. 2 This letter announces the completion of tha NRC staff's Containment' Performance Improvement (CPI) program. Technical insights arising from this effort for PWR containments and for BWR Mark II and Mark III containments are being forwarded via this letter for use in licensee efforts as aart of the Individual Plant Examination (IPE) effort described in Generic Letter 88-20.
No regulatory requirements have resulted from the CPI program for these contairment types.
Similar technical information for BWR Mark I containments was discussed in SECY 89-017, ' Mark I Containment Performance Improvement 1
Program", dated January 23, 1989, and summarized in an enclosure to Generic Letter 88-20, Supplement-I, dated August 29, 1989.
The technical information y
may be useful to licensees during their examinations of their plants for
'b vulnerabilities to severe accidents.
d Four specific insights are believed by the staff to be important'enough to bring.to the attention of licensees for use as they detarmine appropriate in h
the IPE for the plant types to which they apply.
These insights are briefly I
summarized below. As final technical reports providing additional detail are f
)ublished, they will ha =ua avaHable to all licensees l Licensees should i~sar in mind that the insights listed below are not all inclusive and unique
! plant features, may exist that also warrant consideration in the IPE. Licen.r e h e-to re. n 4,r um We "e,c t, ge ' hir est be. nh:en Asent a. 3 4 t m Ti Mark 11 containments hat c.h m arosof.(,tksrc arwn ant / pre ve e'en.
For events where inadequate containment heat removal couli ca~use core degradation, additional containment heat removal capability using plant-specific hardware procedures is expected to be considered as part of the IPF process.
Potential methods of removing hat from containment inc.iade, but are not limited to, using a hardened vent or other means of itaproving reliability of supprer;sion pool cooling.
It is expected that-the negative as well as the positive benefits of-the enhanced containment heat removal capability will be considered.
For example, for those events where venting is init'.al.s after core melt and subsequent vessel failure have occurred, tne benefit of scrubbing of fission products care not La assured for Mark II containments to the same degree as in Mark I plants. This is because molten core materials on the floor of the containment may fail downcomers or drain lines and result in suppression pool bypass.
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