ML20149K929
| ML20149K929 | |
| Person / Time | |
|---|---|
| Issue date: | 07/25/1997 |
| From: | Lobel R NRC (Affiliation Not Assigned) |
| To: | Berlinger C NRC (Affiliation Not Assigned) |
| References | |
| NUDOCS 9707300255 | |
| Download: ML20149K929 (40) | |
Text
, j P "'%g -
ft UNITED STATES j
fgk
~
T.L NUCLEAR REGULATORY COMMISSION
. t WASHINGTON. D C. 20555-0001 July 25,1997 MEMORANDUM T0: Carl Berlinger. Chief Containment Sy ,
es and Severe Accident Branch. DSSA FROM: Richard Lobel gk2d C Containment Systems and Severe Accident Branch. DSSi
SUBJECT:
J'JLY 17,1997 MEETING WITH THE NUCLEAR ENERGY INS':,UTE (NEI)
AND THE WESTINGHOUSE OWNERS GROUP (WOG). THE COMBUSTION ENGINEERING OWNERS GROUP (CEOG). AND THE BABC0CK AND WILC0X OWNERS GROUP (BWOG) TO DISCUSS THE POTENTIAL BLOCKAGE OF THE EMERGENCY CORE COOLING SYSTEM (ECCS) SUMP DURING RECIRCULATION FOLLOWING A LOSS-0F-COOLANT ACCIDENT (LOCA)
The Naclear Regulatory Commission (NRC) staff held a meeting in Rockville. MD on Thursday, July 17. 1997, with the Nuclear Energy Institute (NEI) and the Westinghouse Owners Group (WOG). the Combustion Engineering Owners Group (CEOG). and the Babcock and Wilcox Owners Group (BWOG) to discuss the potential for blockage of the emergency core cooling system (ECCS) sump by debris generated by a loss-of-coolant accident (LOCA).
The meeting was requested by the NRC staff in a conference call with representatives of NEI and the Pressurized Water Reactor (PWR) Owners Groups on June 17. 1997. The purpose of the meeting was to inform NEI and the PWR Owners Groups of preliminary work done by the NRC staff in identifying potential problems related to recirculation of coolant following a LOCA in PWRs and informing NEI and the PWR Owners Groups of the work that had been done by the staff. the Boiling Water Reactor Owners Group (BWROG), and licensees with boiling water reactors in resolving a similar issue. A representative of the BWROG attended this meeting.
Attachment 1 is an attendance list. Attachment 2 contains the viewgraphs used by the staff at the meeting. There were no prepared presentations by NEI or the PWR Owners M ups.
The meeting was opened by Richard Lobel of the Containment Systems and Severe Accident Branch in the Office of Nuclear Reactor Regulation (NRR). Mr. Lobel discussed the underlying safety concern which led the staff to request the meeting. This safety concern is loss of adequate net positive suction head to the ECCS pumps during a LOCA caused by blockage of the ECCS sump screens by debris. The NRC staff considers this to be a com)liance issue. 10 CFR 50.46 requires, among other things, that the ECCS will 3e able to remove long-term decay heat following a LOCA. In a PWR this is accomplished by recirculating water to the ECCS sump. Hence, the concern with sump blockage. v_,y LJ1'L g Q .) , n (p i. r; I.
9707300255 970725 PDR REVGP ERGN C _g g g gg FiE CEM 0 g me t~em W,, 4&QA$%
! design deficiencies, and problems with protective coatings. This generic letter also requires information on protective coatings. Page 31 of the attached viewgraphs discusses the relationship of these generic letters to the new work discussed at this meeting.
After the presentations there was a discussion about the best way to proceed.
It was decided that John Butler of NEI would be the industry contact until NEI and the owners groups decide on the approach they would like to use to interact with the staff.
A participant asked about the use of leak-before-break and risk informed regulation as two ap3 roaches to assist in resolving this issue. The staff res)onded that leak-]efore-break and risk were not accepted by the staff while wor (ing on the related BWR issue. The staff considers this issue to be a compliance issue in that the licensee must be able to demonstrate the ability to satisfy the applicable design basis accident criteria.
The staff was asked about the possibility of a joint NRC-industry test program. The staff responded that this may be~ acceptable for the concerns dealing with protective coatings. However, for the concern with ECCS sump blockage. the staff preferred to work independently but share information and opinions on any testing programs.
Several questions were asked regarding protective coatings.
The NRC staff then thanked the attendees for coming and the meeting was adjourned.
cc: Gary Holahan Scott Newberry DISTRIBUTION w/ Attachment 2:
J. Davis John Butler. NEI D. V. Rao. SEA. Inc. R. Lobel R. Elliott A. Serkiz M. Marshall J. Davis Central Files PDR SCSB r/f (2) w/o Attachment 2:
J. Kudrick D. Mathews S. Magruder J. Strosnider J. Lyons DOCUMENT NAME: PWROGMTG. SUM RL OFFICE: SCSB/DSSA/NRR NAME: RLo 1:bw DATE: 7/1 /97
_2 t ,
The staff has begun an examination of this concern for the PWRs. The goal of this effort, at this point. is to determine if there is a need for further NRC action to be taken for PWRs beyond that taken during the original resolution of Unresolved Safety Issue (USI) A-43. " Containment Emergency Sump Performance". This 'ssue was resolved with issuance on December 3. 1985 of NRC Generic Letter 85-22. " Potential for Loss of Post-LOCA Recirculation Capability Due to Insulation Debris Blockage" Mr. Robert Elliott from the Containment Systems and Severe Accident Branch then reviewed the history of the staff's and the BWROG's ef forts to resolve the issue of blockage of ECCS strainers in the suppression pools of BWRs. As discussed in the meeting's viewgraphs, there were several events at operating BWRs and several NRC bulletins were issued. NRC Bulletin 96-03. " Potential Plugging of Emergency Core Cooling Suction Strainers by Debris in Boiling Water Reactors". dated May 6.1996 provided the final NRC guidance for resolution of this issue. The BWROG prepared a document called the Utility
.tesolution Guidance (URG) which provMes implementation guidance to the BWR licensees.
Mr. Michael Marshall of the Office of Nuclear Regulatory Research (RES) discussed the concerns which have been raised in a preliminary review of the resolution of USI A-43 based on what the staff has learned from a re-review of the USI A-43 work and the knowledge gained from the BWR work in this area.
Some of these concerns are the following:
e More debris may be generated than assumed in A-43. Also, more of
, this material may be fine particles (more capable of reaching and blocking the sump) than assumed in USI A-43.
- Based on the work done for USI A-43. it was assumed that debris would settle before reaching the sump if the water velocity was less than 0.2 feet per second and the debris had a specific gravity of greater than 1.05. New evidence shows that a lower velocity must be reached before the debris will settle.
e The BWR work demonstrated the existence of a 3henomenon termed filtration by which fibrous debris (such as tlat from thermal insulation) captures particulates and produces a much higher pressure drop across the screens than would otherwise be expected.
This phenomenon may be applicable to PWRs also. It was not considered by USI A-43.
e Previous work ,:u USI A-43 did not consider turbulence in the flow carrying debris to the sump. Such turbulence may increase the l capability of the flow to carry debris further.
l l Mr. Lobel then discussed the relationship between this work and two generic letters that the staff is proposing to issue in the near future. One generic letter requests information on NPSH for the ECCS pumps. The second discusses foreign material exclusion concerns, degradation of sumps and strainers.
l l
e i
design deficiencies, and problems with protective oatings. This generic letter also requires information on protective coatings. Page 31 of the attached viewgraphs discusses the relationship of these generic letters to the new work discussed at this meeting.
After the presentations there was a discussion about the best way to proceed.
It was decided that John Butler of NEI would be the industry contact until NEI and the owners groups decide on the approach they would like to use to interact with the staff.
A participant asked about the use of leak-before-break and risk informed regulation as two ap3 roaches to assist in resolving this issue. The staff res]onded that leak-Jefore-break and risk were not accepted by the staff while worcing on the related BWR issue. The staff considers this issue to be a compliance issue in that the licensee must be able to demonstrate the ability to satisfy the applicable design basis accident criteria.
The staff was asked about the possibility af a joint NRC-industry test program. The staff responded that this may be acceptable for the concerns dealing with protective coatings. However, for the concern with ECCS sump blockage. the staff preferred to work independently but share information and opinions on any testing programs.
Several questions were asked regarding protective coatings.
The NRC staff then thanked the attendees for coming and the meeting was l adjourned.
cc: Gary Holahan l Scott Newberry l DISTRIBUTION w/ Attachment 2:
J. Davis John Butler. NEI D. V. Rao SEA. Inc. R. 'obel R. Elliott A. aerkiz M. Marshall J. Davis Central Files PDR SCSB r/f (2) w/o Attachment 2:
J. Kudrick D. Mathews S. Magruder J. Strosnider J. Lycns DOCUMENT NAME: ,PWROGMTG. SUM SL OFFICE: SCSB/DSSA/NRR NAME: RLobel:bw DATE: 7/,d/97
i
'! design deficiencies, and problems with protective coatings. This generic ,
, letter also requires information on protective coatings. Page 31 of the '
, attached viewgraphs discusses the relationship of these generic letters to the new work discussed at this meeting.
After the presentations there was a discussion about the best way to proceed. ;
It was decided that John Butler of NEI would be the industry contact until NEI and the owners groups decide on the approach they would like to use to I interact with the staff. I
- A participant asked about the use of leak-before-break and risk informed
- regulation as two ap3 roaches to assist in resolving this issue. The staff res]onded that leak-Jefore-break and risk were not accepted by the staff while
, wor (ing on the related BWR issue. The staff considers this issue to be a {
compliance issue in that the licensee must be able to demonstrate the ability 1
- to satisfy the applicable design basis accident criteria.
. The staff was asked about the possibility of a joint NRC-industry test d
program. The staff responded that this may be acceptable for the concerns dealing with protective coatings. However, for the concern with ECCS sump blockage. the staff preferred to work independently but share information and opinions on any testing' programs.
1 Several questions were asked regarding protective coatings.
i The NRC staff then thanked the attendees for coming and the meeting was I adjourned. j l
- cc: Gary Holahin Scott Newberry i
i
- DISTRIBUTION w/ Attachment 2:
J. Davis John Butler. NEI
. D. V. Rao, SEA. Inc. R. Lobel
- R. Elliott A. Serkiz M. Marshall J. Davis Central Files PDR i
SCSB r/f (2) ,
) w/o Attachment 2:
i J. Kudrick D. Mathews S. Magruder J. Strosnider J. Lyons DOCUMENT NAME: PWROGMTG. SUM RL OFFICE: SCSB/DSSA/NRR NAME: RLo 1:bw DATE: 7/1 /97
The staff has begun an examination of this concern for the PWRs. The goal of this effort, at this point, is to determine if there is a need for further NRC action to be taken for PWRs beyond that taken during the original resolution of Unresolved Safety Issue (USI) A-43. " Containment Emergency Sump Performance". This issue was resolved with issuance on December 3. 1985 of NRC Generic Letter 85-22. " Potential for Loss of Post-LOCA Recirculation Capability Due to Insulation Debris Blockage" Mr. Robert Elliott from the Containment Systems and Severe Accident Branch then reviewed the history of the staff's and the BWROG's efforts to resolve the issue of blockage of ECCS strainers in the suppression pools of BWRs. As discussed in the meeting's viewgraphs, there were several events at operating BWRs and several NRC bulletins were issued. NRC Bulletin 96-03. " Potent.ial Plugging of Emergency Core Cooling Suction Strainers by Debris in Boiling Water Reactors", dated May 6.1996, provided the final NRC guidance for resolution of this issue. The BWROG prepared a document called the Utility Resolution Guidance (URG) which prov' des implementation guidance to the BWR licensees.
Mr. Michael Marshall of the Office of Nuclear Regulatory Research (red) discussed the concerns which have been raised in a preliminary review of the l resolution of USI A-43 based on what the staff has learned from a re-review of the USI A-43 work and the knowledge gained from the BWR work in this area.
Some of these concerns are the following:
e More debris may be generated than assumed in A-43. Also, more of this material may be fine particles (more capable of reachirig and blocking the sump) than assumed in USI A-43.
e Based on the work done for USI A-43, it was assumed that debris would settle before reaching the sump if the water velocity was less than 0.2 feet per second and the debris had a specific gravity of greater than 1.05. New evidence shows that a lower velocity must be reached before the debris will settle.
e The BWR work demonstrated the existence of a 3henomenon termed filtration by which fibrous debris (such as tlat from thermal insulation) captures particulates and produces a much higher pressure drop across the screens than would otherwise be expected.
This phenomenon may be applicable to PWRs also. It was not considered by USI A-43.
- Previous work in USI A-43 did not consider turbulence in the flow carrying debris to the sump. Such turbulence may increase the capability of the flow to carry debris furt her.
Mr. Lobel then discussed the relationship between this work and two generic letters that the staff is proposing to issue in the near future. One generic letter requests information on NPSH for the ECC5 pumps. The second discusses foreign material exclusion concerns, degradation of sumps and strainers.
design deficiencies. and problems with prctective coatings. This generic letter also requires information on protective coatings. Page 31 of the attached viewgraphs discusses the relationship of these generic letters to the new work discussed at this meeting.
After the presentations there was a discussion about the best way to proceed.
It was decided that John Butler of NEI would be the industry contact until NEI and the owners groups decide on the approach they would like to use to interact with the staff.
A participant asked about the use of leak-before-break and risk informed regulation as two ap3 roaches to assist in resolving this issue. The staff resaonded that leak-Jefore-break and risk were not accepted by the staff while wor (ing on the related BWR issue. The staff considers this issue to be a compliance issue in that the licensee must be able to demonstrate the ability to satisfy the applicable design basis accident criteria.
The staff was asked about the possibility of a joint NRC-industry test program. The staff responded that this may be acceptable for the concerns dealing with protective coatings. However. for the concern with ECCS sump blockage. the staff preferred to work independently but share information and
- opinions on any testing programs.
Several questions were asked regarding protective coatings.
The NRC staff then thanked the attendees for coming and the meeting was ;
adjourned.
cc: Gary Holahan Scott Newberry j
l
. - _ - - - - . - . - . . . . - . . . ~ - . - . . - - - . _ . - - - - - - - . .-
i
~
l Attachment 1
- i
, PWR SUMP ISSUES NRC/PWR OWNERS GROUPS i
- JULY 17. 1997 i ATTENDANCE LIST i i
W NAME AFFILIATION PHONE NUMBER l
3 John Butler NEI 202 739 8108 Dave Modeen NEI 202 739 8084 Avtar Singh EPRI 415 855 2384 4
Ies England Entergy 601 368 5766
, Tem Green BWROG/GE 408 925 1308 1.
' Bill Houston Sequoia Consulting Group 904 461 8774 Gordor, Buchoff CEOG/ABB 860 285 5494 l Roger Newton WEPCo/WOG 414 221 2002
- Kenneth Slaby Westinghouse Electric 412 374 4452
! Karl Jacobs NYPA/WOG 914 681 6262 Keith Jensen LNL/WOG 803 857 1327
- Jan Bostleman ITS 505 254 1005
- Kerri Kavanagh NRC/SRXB 301 415 3743 )
j D. V. Rao SEA. Inc. 505 884 2300 Mohammed Shuaibi NRC/SRXB 301 415 2859
- Steve Katradis NUS Information Svcs. 301 258 2448 .
i Ray Rosten Duke Engineering 630 778 4329 Joe Kelly Framatome Technologies 804 832 2964 i Bill Foster Duke Power 864 885 3163 l Toshiyuki Zamma TEPCo 202 457 0790
- Franklin Coffman NRC/RES/GSIB 301 415 5704
- Frank Cherny NRC/RES/GSIB 301 15 6786 Wayne Scott NPC/NRR/HOMB 301 415 1020 Mike Shoppman FP&L 301 656 6100 l Theresa Sutter Bechtel 301 417 4244
! Dan Patton Bechtel 301 228 6070 l i Gordon Hart Performance Contracting. Inc. 913 441 0100 :
! Ken Wilson Entergy Operations Inc
-Waterford 504 739 6221
- Milton Huff Entergy Operations Inc - AND 501 858 4326
- J Kudrick NRC 301 415 8071 Rob Elliott NRC/NRR/SCSB 301 415 1397 Michael Marshall NRC/RES 301 415 5895
] Richard Lobel NRC/NRR/SCSB 301 415 2865 Al Serkiz NRC/RES 301 415 6563
NRC MEETING WITH PWR OWNERS GROUPS TO DISCUSS BLOCKAGE OF ECCS SUMPS BY LOCA-GENERATED DEBRIS gn REcy,
+ .g e~ "
- I 1 S g
c-( . r.
s +++++
@ J a y C0 Richard Lobel l Robert Elliott f Michael Marshall U.S. Nuclear Regulatory Commission g C
9 July 17,1997 j Public Meeting [
Rockville, Maryland 3 e 4 %
AGENDA
- 1. Introduction (Richard Lobel, NRC)
Discussion of safety concern and the regulatory basis.
- 2. Discussion of BWR history ofissue (Rob Elliott, NRC)
- 3. Discussion of concerns since USI A-43 (Michael Marshall, NRC)
- 4. Discussion of relationship betweer, this work and GLs on NPSH and debris and protective coaljags problems (Richard Lobel, NRC)
- 5. Open Discussion (NRC/NEI/ Owners Groups)
Discussion of future work on this issue and working relationship with PWR OGs and NEI 4
0 Public Meeting w/ Niil and PWR OGs / 7 'g
~Ihursday. July I7.1997 i( - !
% . .:. . /
- . . _ = - . . . . _ - . . . - . - - . . _ . _ . . . . . - . . . . - . . - . _ . . - . . . . - . . _ . . - .. . . . . . . . . . . . -
INTRODUCTION i
i ga REGg G 47 >>
q\
4 \
4 x !
O A y c.- > g ,
4 I I O O (A j
' ,, (1)4*hf
-..,b. c7
- - t vg N,c .
'/ MW. O
++*** ,
Richard M. Lobel U.S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Disision of Systems Safety and Analysis i Containment Systems and Sesere Accident Branch (301)415-2865 t
July 17,1997 Public Meeting Rocksille, Mary land ,
. . . r SAFETY CONCERN LOSS OF ADEQL ATE NPSH TO ECCS PL WPS DLRING A LOCA BLOCKAGE OF ECCS St MP SCREENS BY DEBRIS i
f.** %,
l'ublic Meeting w/ NI:1 and I' Wit OGs l N, ...;g -
I hursday, July 17.1997
- 5. id-y [f
SAFETY CONCERN COMPLIANCE ISSUE 10 CF.R 50.46 THE CALCULATED CORE TEMPFRATURE SHALL BE MAINTAINED AT AN ACCEPTABLY LOW VALUE AND DECAY HEAT SHALL BE REMOVED FOR THE EXTENDED PERIOD OF TIME REQUIRED BY LONG-LIVED RADIOACTIVITY REMAINING IN THE CORE.
p" ~%,,
.OIE0liOS"""""" ( )
.. .I
SAFETY CONCERN t
i THE GOAL OF THIS EFFORT IS TO DETERMINE IF THERE IS A NEED '
FOR FURTHER NRC ACTION TO BE TAKEN FOR PWRs BEYOND THAT TAKEN DURING THE ORIGINAL RESOLUTION OF USI A-43. !
i i
Public Meeting w/ NI.'I and I'WR OGs f' g
'I hursday, July 17.1997
- 5. ( . ' ! ,
%.;;..s t i
f
- m. _ . _ _ _ _ _ _ _____ _ _ _ _ _ _ _ _ _ _ _ _ _ . _ _ _ _ _ _ _ . _ _ _ _ _ _ _ _ . _ . _ . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . _ _ _ _ _ _ _ _ _ . _ _ . _ _ _ _ . _ _ _ _ _ . . _ . . _ _ . _ . _ . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ . _ _ . _ _ _ _ . _ _ . _ _ _ _ _ _
1 USI A-43
" CONTAINMENT EMERGENCY SUMP PERFORMANCE" GL 85-22 " POTENTIAL FOR LOSS OF POST-LOCA RECIRCULATION CAPABILITY DUE TO INSULATION DEBRIS BLOCKAGE" DECEMBER 3,1985 f
e A SINGLE SOLUTION WAS NOT POSSIBLE. DEBRIS BLOCKAGE EFFECTS ARE GOVERNED BY PLANT SPECIFIC FEATURES e 50% SCREEN BLOCKAGE CRITERION SHOULD BE REPLACED WITil A MORE COMPREHENSIVE REQUIREMENT TO ASSESS DEBRIS EFFECTS ON A PLANT-SPECIFIC BASIS
- TECHNICAL FINDINGS SUMMARIZED IN NUREG 0897 REVISION 1 " CONTAINMENT EMERGENC'i SUMP PERFORMANCE" OCTOBER 1985
- NO NEW REQUIREMENTS NEED BE IMPOSED e NO RESPONSE REQUIRED e RECOMMEND THAT REGULATORY GUIDE 1.82 REVISION 1 BE USED AS GUIDANCE IN DEALING WITH MODIFICATIONS TO THERMAL INSULATION INSIDE CONTAINMENT l'ubhc Meeting w/ NEl and I'WR OGs _i i I hursday, July 17.1997 5 j
BARSEB CK i
r r
IN 92-71 " PARTIAL PLUGGING OF SUPPRESSION POOL STRAINERS AT A FOREIGN BWR" SEPTEMBER 30,1992 i l'ublic Meeting w/ NEl and I'WR OGs
[s , , *g Ihursday. July I7.1997 s, (' f- )
% . . l. . '
L DISCUSSION OF BWR HISTORY OF ISSUE i
4
/gn REGg,% ,
% 9 (% $
A y e#3 g O '
q O r
B s
\~Q
,y t
.r, M
. g.3 y r- -
%e g'\6N') w. &
Y***M
[
r Robert 11. tilliott U.S. Nuclear Regulatory Commission OITice of Nuclear Reactor Regulation ;
Disision of Systems Safety and Analysis ,
Containmer;t Systems and Sescre Accident tiranch .
(301)415-1397 l i
I July 17,1997 Public Meeting Rockville, Maryland f
l I
BARSEB CK e
IN 92-71 " PARTIAL PLUGGING OF SUPPRESSION POOL STRAINERS AT A FOREIGN BWR" SEPTEMBER 30,1992 e
ECCS STRAINERS DESIGNED SO THAT BACKFLUSHING NOT NECESSARY FOR FIRST 10 HOURS FOLLOWING AN AC IDENT e REACTOR AT LOW POWER (1 TO 2 PER CENT),435 PSI e LEAKING PILOT VALVE CAUSED SAFETY VALVE TO OPEN e REACTOR SCRAM, SAFETY INJECTION, CONTAINMENT JPRAY INITIATED e
STEAM DISCHARGE FROM OPEN SAFETY VALVE DISLODGES THERMAL INSULATION o TWO OF FIVE STRAINERS CLOGGED - CONTAINMENT SPR AY PUMPS AFFECTED o
OPERATORS SUCCESSFULLY BACKFLUSHED STRAINERS AND SHUT DOWN REACTOR Public Meeting w/ NEI and I'WR OGs y== '* %,,
1 hursday. July 17,1997 f j .. , , ;
S. Q i. 5 ' !
~'. . . ' , *. '
PERRY IN 93-34: "POTENTI AL FOR LOSS OF EMERGENCY CORE COOLING FUNCTION DUE TO A COMBINATION OF OPERATIONAL AND POST-LOCA DEBRIS IN CONTAINMENT" APRIL 16, 1993 e
MAY 1992 REFUELING OUTAGE: INSPECTION OF SUPPRESSION POOL FINDS DEBRIS ON STRAINERS AND TWO RHR STRAINERS DEFORMED (BUCKLED AND CRACKED)
- MARCil 1993: SAFETY RELIEF VALVE LIFTED. RHR USED FOR SUPPRESSION POOL COOLING. TEST RUN OF RHR AFTER EVENT RESULTS IN LOSS OF SUCTION PRESSURE.
ATTRIBUTED TO FIBROUS AIR FILTER MATERIAL IN SUPPRESSION POOL.
e INTERACTION BETIVEEN FIBROUS MA TERIAL AND PARTICULA TES IN SUPPRESSION POOL
- NRC BULLETIN 93-02: " DEBRIS PLUGGING OF EMERGENCY CORE COOLING SUCTION STRAINERS" MAY l1,1993 (ADDRESSED TO BOTH PWRS AND BWRS) e IDENTIFY SOURCES OF FIBROUS MATERI AL NOT DESIGNED TO WITHSTAND A LOCA AND TAKE IMMEDIATE COMPENSATORY ACTIONS
~
f* *%, ,
Public Meeting w/ Nlil and I'WR UGs
'I hursday, July 17,1997 ['Tpg\!
i 1
- _. s_ _- _ _ _ _ _ _____ _ _ _ _ _ _ _ _ . _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
9 BULLETIN 93-02 SUPPLEMENT 1 BULLETIN 93-02 SUPPLEMENT 1: " DEBRIS PLUGGING OF EMERGENCY CORE COOLING SUCTION STRAINERS" FEBRUARY l8,1994 e
STAFF CALCULATIONS SHOW THAT A POTENTIAL EXISTS TO CLOG STRAINERS AT MOST BWRS BULLETIN 93-02 SUPPLEMENT 1 REQUESTS:
+
TRAINING TO OPERATORS. AWARENESS OF POSSli>ILITY OF STRAINER BLOCKAGli i
+ ASSURANCE OF ADEQUATE PROCEDURES.
+ COMPENSATORY ACTIONS TO PREVENT, MITIGATE, OR DELAY LOSS OF NPSil f ~%,
l'ublic Meeting w/ NI:1 and 1*WR OGs lhursday . July 17.1997 i 'r c/i
'%y ] t
LIMERICK UNIT 1
- SEPTEMBER 11,1995 LIMERICK UNIT 1 100% POWER
- ONE SAFETY RELIEF VALVE OPENED e AFTER 30 MINUTES, OPERATOk NOTES FLUCTUATING MOTOR CURRENT AND FLOW OF Ril!! PUMP e PUMP STOPPED AND RESTARTED AT LOWER FLOW RATE. OPERATOR GRADUAliJ INCREASED FLOW ,
RATE e BOTil RilR SUCTION STRAINERS FOUND COVERED WITil TilIN MAT OF MATERIAL
- NRC BULLETIN 95-02," UNEXPECTED CLOGGING OF A RESIDUAL IIEAT REMOVAL PUMP STRAINER WillLE OPERATING IN TIIE SUPPRESSION POOL COOLING MODL" OCTOBER 17,1995 -
- BULLETIN 95-02 REQUESTS:
+ VERIFYING OPERABILITY OF ALL ECCS PUMPS BASED ON CLEANLINESS OF SUPPRESSION POOL
+ ESTABLISil AND SCIIEDULE A SUPPRESSION POOL CLEANING
+ REVIEW FOREIGN MATERIAL EXCLUSION PROCEDURES / IDENTIFY WEAKNESSES,IF ANY c.. % ,
Public Meeting w/ NEl and PWR OGs ;x, ,. - ";
Thursday, July 17,1997
( (c3 / ,I
% , ,',', , l .
4
.. . _ . . .= - .
RESOLUTION OF ISSUE FOR BWRS I
e REVISION 2 TO REGULATOR GUIDE 1.82," WATER SOURCES FOR LONG-TERM PECIRCULATION COOLING FOLLOWING A LOSS-OF-COOLANT ACCIDENT" MAY 1996
+ REVISED GUIDANCE FOR 13WRs NRC BULLETIN 96-03, " POTENTIAL PLUGGING OF EMERGENCY CORE COOLING SUCTION '
STRAINERS BY DEBRIS IN BO' LING WATER REACTORS" MAY 6,1996
+ REQUESTS 13WR LICENSEE 5 ADOPT ONE OF TilREE OPTIONS TO RESOLVE ISSUE -
- 1. LARGE PASSIVE STRAINERS
- 2. 13ACKFLUSillNG 3 SELF-CLEANING STRAINERS I
- FIRST REFUELING OUTAGE AFTER JANUARY 1,1997 BWR OWNERS' GROUP UTILITY RESOLUTION GUIDANCE FOR ECCS SUCTION STRAINER BLOCKAGE NOVEMBER 20,1996 o BWR LICENSEE IMPLEMENTATION o STRAINERS ARE BEING SIZED AN ORDER OF MAGNITUDE OR HIGHER p>=~= , ;
Public Meeting w/ N!!! and PWR OGs
't hursday, July 17,1997
[j , ,.,, d Wj m Ja' !
%.::../
DISCUSSION OF PWR DEBRIS BLOCKAGE CONCERNS AND PROPOSED RES PROGRAM ggR REcog j
+
,y ?s A y c- 0 4
- n-
- g; 't 4
.,, e O
~ '
O ,, ,6 _".
g3 '
.-r -
4 ,
Y' sI. yYh Nb i O :
- Y hiichael I,. h1arshali, Jr.
U.S. Nuclear Regulatory Commission !
Ollice of Nuclear Regulatory Research t Dis ision of Engineering Technology Generic Safety issues liranch (301)415-5895 July 17,1997 Public hiceting Rockville, hianland I t
t
. f t
5
DEBRIS BLOCKAGE CONCERNS: OVERVIEW o Debris Threats
+ Reduced NPSII Margin
+ Impede Flow of Water e Conventional Wisdom (USI A-43 vs Current)
+ Debris Generation
+ Debris Tra isport
+ Debris Ilead I.oss
+ Variability of Sump Design t
l'ublic Meeting w/ NEl and l'WR OGs
- y. ~ . ,, .
I hursday. July 17,1997 [s s, ' '
-.g s., s y
..... i
.b* .
t
DEBRIS BLOCKAGE CONCERNS: OVERVIEW m,=,,,,=
3jg. g
. . ~, . -
- - . . _ a ..e 9.2m 2 M~-*.~ ,
n ./ I l t., cr
. Tr ro i f
T
{ V ~ s e s, .-- ; q- ,.-
..t. =u
[- _~
'R&,3 S.
.J 0.
. g w.p ..
,I e
r e ;__
.. ,h;,q L' '
i :
j
. ..ie
\
' f j .i" e-) 0:,2'"W ,
,c.,,,t. A' ! I~~ % I
/ "~ *~~'t me L -_.. _a_td ' _, N.,s'}.3
(.
" ~ ' ~ ' " ~
\ j h '
s-~~**
-d] 2 5 cra=s r==x
.. \
7 _ < .-- -a A
/
-r - 4 ,.
/,/wgn : 7 as o;\
W-= - '
f ..
( R...
5
- . . . . . . ,-.... ..., ,m,w W C 3
,- ,'. T... .
NM m..
S/
- g
== C4 _. i.W' ,
1
=
~ *, .
( <. .-.~,...].
, c ._
. * N
, . , . ;- c.*- -*
[ a.... -
, .; f .
- 5 team Genereter excerpt irom FURL:0 UK-2403
[ \ ., ; 2
- i?_- :q
{
""*'**",**'.*,""Q""N El. $9 3' 6'
'.".J':* "J" ".
l Public !.lecting w/ NI:1 and PWR OGs ~c.-ss
~
.?
thursday. July 17.1997 j -;,
i, . ,/
t 9
CONCERNS: REDUCED NPSH MARGIN e Addressed During USI A-43 e Deleterious Effect
+ Accumulation of Debris on Debris Screen increases Resistance Thus Reducing NPSII Margin t e
Locations
+ Debris Screens Attached to Suction Piping e Addressed
+ Calculate llead Loss Caused by Debris Accumulation
+ Reduce Surface Area of Debris Screen by Debris Amount and Calculate / vailable NPSil i
Public Meeting w/ NEI and PWR OGs p ' ='< ,
'Itursday, July 17.1997 fj..g'g
- 5. Q : . P /
'2
~
-e
- l
,f' * ***% ag f' h. e i 9;i! i
\
.e o .:.O p* l m . .' ;;
l I
i m
e l
u 9 ,
l H b j iMi@E l {I l m
I .
Ni_$$$
fj$II Nh g lr !
d
' 8" bi lim -
=
g
& e z c> li 1m
.. n a@
m 00 U l M -. l z > ll tu---, >
\
Q U =========
, I N i fa am n I
> ll l
N
~
( h,h[f[ik I-
- h n iG k ,
s a- l
=. ,
1 1
I
CONCERNS: IMPEDE FLOW OF WATER e Not Addressed During USI A-43 e Deleterious Effect
+ Decrease Water IIcight Inside of Sump i
+ Prevent Water From Reaching Sump 1
e Locations
+ Trash Racks / Debris Screen
+ Flowpath .
l i-I i
l j o *%,, ;
Publ;c Meeting w/ NEl and PWR OGs ;1 , ,1 Ihursday. July 17.1997 5, Q':;" / . ,I
% ,;,',, / i
CONCERNS: FLOWPATH SKETCH execrpt from NUREG UR-2403
. ** > : yff *"g,
,f- , N, 6. .......a .) / .,,~3 p 9/ % .,,r?
N =- x N '""*-' '"
ll O f l 0, ,c5 W
'k f
.A 0% ~
gy'= Q . i, . ,
... k'* .: ..
- i'" j-
/ , - -4..a . .. a 7 / ":-
8 .. L L[ IGD-)';. tv di-
~
p 9 N ._ W, '
!. = 8
&((g
- d' '
A' g
( p k{ ?
/
E';""" I
. r,. f. >-
\ ; Shi" 5
- 11
~
+j
'O,.,..%.*Q~ s s 0..df' i! % ...~ ...-... ..-
4;, x -
\ q- -
. .y % I?.' r ,
~~% , . . :.
"."' ";" 2 " " " 1"*.": T.
- = = = -
., .== sec. ., .e. .e.u,, u ...
El. 95 e o=
- p. ~s,,
Public Meeting w/ NEl and PWR OGs
't hursday. July 17.1997
[\ ng[j
'D r.
,. . .'. . / _
CONCERNS: USI A-43 vs CURRENT j '- "f
/\.
/\ \ ; :
z\
\
\ #
,/ \ / \ f \
/ \ / \ s
/ s / s C C C U U U R R R R R R E E E N N N T T T I .
Debris Generation Debris Transport Debris Head Loss t
A -4 3 A-43 A-43 Since 1985 a number of factors have been identified that would increase the amount of debris generation, debris transport, and debris head loss.
Public Meeting w/ NI:1 and I'WR OGs j ,,
'I hursday . July 17.1997 [ $ ,, , ' '
- 5. Qu . 'y! )
% . .~.'. . !
i I
CONCERNS: DEBRIS GENERATION 1
e USI A-43 1
+ Three Region llemispherical Model Based on Analysis and Experiments
+ ~ NUREG/CR-2913 l
i e Current View
+ Debris Can He Generated at Greater Distance Than Predicted with USl A-43 Model i
- + Larger Number of Fines than Previously Assumed in USI A-43 Modeling and Testing
+ Debris Other Than Thermal Insulation Should be Considered
- Particulates !
I f.- ~.,.,,
l'ubhc Meeting v / NEl and 1* Wit OGs ;i i I hursday. July 17,1997 I, h, b,, . / *;,I
~ "
'~..'..' .
i i
1
CONCERNS: DEBRIS TRANSPORT AND ACCUMULATION -
e U:SI A-43
+
If Transport Velocity Is less than 0.2 ft/s and Specific Gravity 21.05, Then Debris Will Settle Before Reaching Debris "creen.
+ IfTransport Velocity Is less than 0.2 ft/s, Then Debris Will Settle Before Reaching Debris Screen.
+ RG l.82, Rev.1 (NUREG/CR-2982) e Current View
+ Transport Possible at Velocity Less Than 0.2 ft/s
- Fibrous i
+ Turbulence Will Prolong (Impede) Settling l
- Break Flow and Containment Spray 6
l raa s.,
l'ublic Niecting w/ NI!I and I'WR OGs f
'Ihursday, July 17.1997
[',
i Q4. .,. - !
}
N . . ', . Y l
[
CONCERNS: DEBRIS HEAD LOSS l e USI A-43 -
+ Empirical IIcad Loss Equat ions Developed l
+
NUREG/CR-2982 (NUREG/c i-2791) '
l e Current View
+ Finer Debris Used to Develop Ilead Loss Correlation Which
+ Filtration ofl' articulates by Fibrous Debris Beds Causes Larger llead Losses i
+ Combinations of Debris May Cause Larger IIcad Loss '
r t
L i
- f. ~ % ,,
Public Meeting w/ Nlil ar:d PWR (Xis /. A Thursday, July 17,1997 !
t e
_ . _ _ _ _ _ _ _ _ . . _ _ _ _ _ _ _ _ _ _ _ . _ _ _ _ _ _ _ _ _ _ _ _ _ .___ _ ____ _____.__ m _
L CONCERNS: USI A-43 vs CURRENT Selected Technical Considerations 1
Same as USI A-43 Changed Since USI A-43 New Variability of Sump Designs Debris Sizes Filtration Postulated LOCA Amount Debris Generated Draw Down of Sump Transport of Debris IIcad Loss Correlations '
tiebris Sources l
Public Alceting w/ Niil and PWit OGs ,.=~c.,,
- x . . ,/ *.
'Ihursday July 17.1997 5,( ," / ,I
- l PROPOSED RES PROGRAM: OVERVIEW e GSI-191, " Assessment of Debris Accumulation on Pressurized Water Reactors Sump Performance" e Conduct a Similar Study to the BWR Study and USI A-43 Study
- Determination of Safety Significance Will Be Based on PWR Survey and Parametric Analysis l
e= *c., !
Public Meeting w/ NI_I and PWR OGs '*
'thurWay July 17,1997 f-~
g i' 'l
'N..,,,*#' .
I 9 $
PROPOSED RES PROGRAM: OVERVIEW t e Survey of PWRs
. Diversity of Sump Designs
. OMB Clearance e Identify and Investigate Debris Sources o Perform Detailed Calculations on Reference Plants
. Review Piping Layouts and Potential Break Locations
. Review Accident Progression and Conditions -
- Calculate Amount of Debris Generated :
. Calculate Amount of Debris Transported !
. Determine Effect of Debris Accumulation e Parametric Analysis mener-
,p= ~ m,,_
PuNic Meetin,* w/ NEl and PWR OGs ;'. ,,*,
liiursdaw July 17,1997 5, (C ' ,f s . . .: . - ;
DISCUSSION OF RELATIONSHIP BETWEEN THIS WORK AND GLS ON NPSH AND DEBRIS AND PROTECTIVE COATINGS PROBLEMS gn REGg, A>
n s k-~ ft }
.,. a O
,' ' t
- d,>+.
- \ ? %e f'4 xe) d 4 . l.
- A Y Richard M. lobel U.S. Nuclear Regulatory Commission .
l Oflice of Nuclear Reactor Regulation Disision of Systems Safety and Analy sis Containment Sy stems and Severe Accident liranch (301)415-2865 i
July 17,1997 i Public Meeting Rocbille, Maryland j
.. .- .. - .- . - .- - - - ..- - . ~ -. - - - . .- . - .-
RECENT GENERIC COMMUNICATIONS GL 97-XX: ASSURANCE OF SUFFICIENT NET POSITIVE SUCTION HEAD FOR EMERGENCY CORE COOLING AND CONTAINMENT HEAT REMOVAL
- SPECIFY NPSH ANALYSES SPECIFY WHETHER CONTAINMENT OVER PRESSURE WAS CREDITED IF CONTAINMENT OVER PRESSURE CREDITED, CONTAINMENT HEAT REMOVAL ASSUMPTIONS TO DETERMINE MINIMUM CONTAINMENT PRESSURE eusuc uxony wi nni ana ewn oos
~1 hursday. July 17,1997 f I'is
[
%.;.../
k_ . -
I RECENT GENERIC COMMUNICATIONS GL 97-XX: POTENTIAL FOR DEGRADATION OF THE EMERGENCY CORE COOLING SYSTEM AND THE CONTAINMENT SPRAY SYSTEM AFTER A LOSS-OF-COOLANT ACCIDENT BECAUSE OF CONSTRUCTION AND PROTECTIVE COATING DEFICIENCIES AND FOREIGN MATERIAL IN THE CONTAINMENT e DISCUSSES FOREIGN MATERIAL EXCLUSION PROBLEMS e DISCUSSES SUMP AND STRAINER CONSTRUCTION DEFICIENCIES e DISCUSSES DEGRADED CONDITIONS OF STRAINERS AND SUMPS e REQUIRES RESPONSES TO QUESTIONS ON PROTECTIVE COATINGS I :ur a ) 17, 7 s.6 -
RELATIONSHIP TO NEW PWR STUDIES RELATED BY IMPACT ON ECCS PUMP NPSH ISSUES WHICH WILL BE ADDRESSED REGARDLESS OF NEW WORK:
- FOREIGN MATERIAL EXCLUSION e CONSTRUCTION DEFICIENCIES e DEGRADATION OF SUMPS AND STRAINERS o DEGRADATION OF PROTCCTIVE COATINGS NEW ISSUES:
o ADEQUATE ALLOWANCE FOR IMPACT OF LOCA-GENER ATED DEBRIS (E.G., DISL.ODGED THERMAL INSULATION, DISLODGED UNQUALIFIED PAINT AND OTHER PARTICULATES) ON ECCS AND CONTAINMENT SPRAY PUMP NPSH WORK ON GLs AND REASSESSMENT OF A-43 ADEQUACY WILL PROCEED INDEPENDENTLYBUTINSIGHTS WILL BE SHARED
,~%,,
Public Mec ing u/ NEl and I'WR OGs a ~
thursday . July 17,1997
[ ) . , , /'-;
5
- - /
- = - .-__
NEED FOR INFORMATION .
INFORMATION:
- SUMP DESIGN
- SUMP LOCATION IN CONTAINMENT
- ECCS PUMP DESIGN PARAMETERS t i
NRC WILL REQUEST INFORM ATION IN ACCORDANCE WITH OUR PROCEDURES AND REGULATIONS :
4
- OMB REQUEST ,
- GENERIC LETTER t
i 1
f - "' . ,
Public Meeting w/ Niil and PWR OGs
) ... / g t i
Ihursday . July 17,1997 i (c u. , ' l
'N . . .'. . *# ,
[
. s .
. . _ _ - - - . - - . - - _ - - - - - - . - _ - _ - _ - _ _ - - , <