Information Notice 1992-71, Partial Plugging of Suppression Pool Strainers at a Foreign BWR: Difference between revisions

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| issue date = 09/30/1992
| issue date = 09/30/1992
| title = Partial Plugging of Suppression Pool Strainers at a Foreign BWR
| title = Partial Plugging of Suppression Pool Strainers at a Foreign BWR
| author name = Rossi C E
| author name = Rossi C
| author affiliation = NRC/NRR
| author affiliation = NRC/NRR
| addressee name =  
| addressee name =  
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| page count = 7
| page count = 7
}}
}}
{{#Wiki_filter:_~K)UNITED STATESNUCLEAR REGULATORY COMMISSIONOFFICE OF NUCLEAR REACTOR REGULATIONWASHINGTON, D.C. 20555September 30, 1992NRC INFORMATION NOTICE 92-71: PARTIAL PLUGGING OF SUPPRESSION POOLSTRAINERS AT A FOREIGN BWR
{{#Wiki_filter:_~K)
                                  UNITED STATES
 
NUCLEAR REGULATORY COMMISSION
 
OFFICE OF NUCLEAR REACTOR REGULATION
 
WASHINGTON, D.C. 20555 September 30, 1992 NRC INFORMATION NOTICE 92-71:   PARTIAL PLUGGING OF SUPPRESSION POOL
 
STRAINERS AT A FOREIGN BWR


==Addressees==
==Addressees==
All holders of operating licenses or construction permits for nuclear powerreactors.
All holders of operating licenses or construction permits for nuclear power
 
reactors.


==Purpose==
==Purpose==
The U.S. Nuclear Regulatory Commission (NRC) is issuing this informationnotice to alert addressees to the potential-for loss of emergency core coolingsystems (ECCS) that was identified as a result of an event at a Swedishboiling water reactor (BWR). It is expected that recipients will review thelinformation for applicability to their facilities and consider actions, asappropriate, to avoid similar problems. However, suggestions contained inthis information notice are not NRC requirements; therefore, no specificaction or written response is required.
The U.S. Nuclear Regulatory Commission (NRC) is issuing this information
 
notice to alert addressees to the potential-for loss of emergency core cooling
 
systems (ECCS) that was identified as a result of an event at a Swedish
 
boiling water reactor (BWR). It is expected that recipients will review thel
 
information for applicability to their facilities and consider actions, as
 
appropriate, to avoid similar problems. However, suggestions contained in
 
this information notice are not NRC requirements; therefore, no specific
 
action or written response is required.


==Description of Circumstances==
==Description of Circumstances==
:On July 28, 1992, Sydkraft AB, the utility licensed by the Swedish regulatoryagency for the BarsebAck nuclear power plant, was restarting Unit 2 after theannual outage. While the reactor was at 1 or 2 percent power and at 435 psi,a leaking pilot valve caused a safety valve for the reactor vessel to open.This valve discharges directly to the drywell. Reactor scram, high pressuresafety injection, core spray, and containment spray systems initiatedautomatically in response to the event. Steam from the open safety valve,impinging on thermally-insulated equipment, dislodged 440 pounds of metal-jacketed, mineral wool. An estimated 220 pounds of insulating material waswashed into the suppression pool. Two of five strainers on the suction sideof the ECCS pumps were in service and became partially plugged with mineralwool. Plugging caused pressure to decrease significantly across the strainersand caused indications of cavitation in one pump in about an hour after theevent began. The operators successfully back flushed the strainers and shutdown the reactor without additional problems.DiscussionIn the safety analysis for Unit 2 of the Barsebdck plant, the licenseeconcluded that the strainers would not require back flushing during the first10 hours after a loss-of-coolant accident. Because of the event of July 28,the Swedish regulatory agency required Barseback Unit 2 and four other unitsof similar design to remain shut down until this problem is resolved.9209290014 e IIIIN 92-71September 30, 1992 This event at BarsebAck is directly applicable to an earlier study conductedby the NRC. That study evaluated the potential for displaced thermalinsulation to form debris and to be drawn to the sump screen. The results ofthe study are documented in "Containment Sump Performance," NUREG-0897,Revision 1, dated March 1984. The NRC concluded that the risk associated withthe sump clogging concern did not warrant backfitting of domestic plants.However, based on the Barsebdck event, this conclusion is being reevaluated.This information notice requires no specific action or written response. Ifyou have any questions about the information in this notice, please contactthe technical contact listed below or the appropriate Office of NuclearReactor Regulation (NRR) project manager.(arles si, DirectorDivision of Operational Events AssessmentOffice of Nuclear Reactor RegulationTechnical contact: Robert L. Dennig, NRR(301) 504-1156
:
On July 28, 1992, Sydkraft AB, the utility licensed by the Swedish regulatory
 
agency for the BarsebAck nuclear power plant, was restarting Unit 2 after the
 
annual outage. While the reactor was at 1 or 2 percent power and at 435 psi, a leaking pilot valve caused a safety valve for the reactor vessel to open.
 
This valve discharges directly to the drywell. Reactor scram, high pressure
 
safety injection, core spray, and containment spray systems initiated
 
automatically in response to the event. Steam from the open safety valve, impinging on thermally-insulated equipment, dislodged 440 pounds of metal- jacketed, mineral wool. An estimated 220 pounds of insulating material was
 
washed into the suppression pool. Two of five strainers on the suction side
 
of the ECCS pumps were in service and became partially plugged with mineral
 
wool. Plugging caused pressure to decrease significantly across the strainers
 
and caused indications of cavitation in one pump in about an hour after the
 
event began. The operators successfully back flushed the strainers and shut
 
down the reactor without additional problems.
 
Discussion
 
In the safety analysis for Unit 2 of the Barsebdck plant, the licensee
 
concluded that the strainers would not require back flushing during the first
 
10 hours after a loss-of-coolant accident. Because of the event of July 28, the Swedish regulatory agency required Barseback Unit 2 and four other units
 
of similar design to remain shut down until this problem is resolved.
 
9209290014     e
 
III
 
IN 92-71 September 30, 1992 This event at BarsebAck is directly applicable
 
by the NRC. That study evaluated the potential to an earlier study conducted
 
insulation to form debris and to be drawn to     for displaced thermal
 
the study are documented in "Containment Sump the  sump screen. The results of
 
Revision 1, dated March 1984. The NRC concluded Performance,"  NUREG-0897, that the risk associated with
 
the sump clogging concern did not warrant backfitting
 
However, based on the Barsebdck event, this             of domestic plants.


===Attachment:===
conclusion is being reevaluated.
List of Recently Issued NRC Information Notices AttachmentIN 92-71September 30, 1992 LIST OF RECENTLY ISSUEDNRC INFORMATION NOTICESInformation Date ofNotice No. Subject Issuance Issued to92-7092-6991-29,Supp.92-6892-671Westinghouse Motor-OperatedValve Performance DataSupplied to Nuclear PowerPlant LicenseesWater Leakage from YardArea Through ConduitsInto BuildingsDeficiencies IdentifiedDuring Electrical Dis-tribution System Func-tional InspectionsPotentially SubstandardSlip-On, Welding Neck,and Blind FlangesDeficiency in DesignModifications to Ad-dress Failures ofHiller Actuators UponA Gradual Loss ofAir PressureAccess Denied to NRCInspectors at Five StarProducts, Inc. andConstruction ProductsResearch, Fairfield,ConnecticutSafety System ProblemsCaused by ModificationsThat Were Not AdequatelyReviewed and Tested09/25/9209/22/9209/14/9209/10/9209/10/9209/01/9209/03/9208/28/92All holders of OLs or CPsfor nuclear power reactors.All holders of OLs or CPsfor nuclear power reactors.All holders of OLs or CPsfor nuclear power reactors.All holders of OLs or CPsfor nuclear power reactors.All holders of OLs or CPsfor nuclear power reactors.All holders of OLs or CPsfor nuclear power reactorsand all recipients ofNUREG-0040, "Licensee, Con-tractor and Vendor Inspec-tion Status Report" (White.Book).All holders of OLs or CPsfor nuclear power reactors.All holders of -OLs or CPsfor nuclear power reactors.92-6692-6592-64Nozzleon LowReliefRing SettingsPressure Water-ValvesOL = Operating LicenseCP = Construction Permit K><YIN 92-71September 30, 992This event at Barseback is directly applicable to an earlier study conductedby the NRC. That study evaluated the potential for displaced thermalinsulation to form debris and to be drawn to the sump screen. The results ofthe study are documented in "Containment Sump Performance," NUREG-0897,Revision 1, dated March 1984. The NRC concluded that the risk associated withthe sump clogging concern did not warrant backfitting of domestic plants.However, based on the BarsebAck event, this conclusion is being reevaluated.This information notice requires no specific action or written response. Ifyou have any questions about the information in this notice, please contactthe technical contact listed below or the appropriate Office of NuclearReactor Regulation (NRR) project manager.Original Signed byCharles E. RossiCharles E. Rossi, DirectorDivision of Operational Events AssessmentOffice of Nuclear Reactor RegulationTechnical conitact: Robert L. Dennig, NRR(301) 504-1156List of Recently Issued NRC Information Notices


===Attachment:===
This information notice requires no specific
Document Name: 92-71.IN*SEE PREVIOUS CONCURRENCES*OEAB:DOEA:NRR*SC/OEAB:DOEA:NRRRWWoodruff RLDennig09/24/92 09/24/92V CEp/azeSC~hLAt_- Jest)o1i A e- ,L .IDO *C/OGCB:DOEA:NRR*RPB:ADMC GHMarcus TechEd09/; 92 09/28/92 09/24/24*C/OEAB:DOEA:NRR*C/SPLB:DST:NRR ICEP/OIPwAChaffee CEMcCracken AKenqeke09/k8/92 09/1r/92 09/dg/92ago,. 4 e, am ASCo-- -I rw W. 4.4a NRCIN 92-XXSeptember xx, 1991 documented in "Containment Sump Performance," NUREG-0897, Revision 1, dated March1984. The NRC concluded that the risk associated with the sump clogging concerndid not warrant backfitting of domestic plants. However, based on the Barsebackevent and NUREG-0897, Revision 1, this conclusion is being reevaluated.This information notice requires no specific action or written response. If youhave any question about the information in this notice, please contact thetechnical contact listed below or the appropriate Office of Nuclear ReactorRegulation project manager.-Charles E. Rossi, DirectorDivision of OperationalEvents AssessmentOffice of Nuclear Reactor RegulationTechnmical Contact:Robert L. Dennig, NRR(301) 504-1156


===Attachment:===
action or written response. If
1. List of Recently Issued Information Notices* See previous page for concurrence.CONCURRENCE:OEAB*RWWoodruff09/24/92D:DOEACERossi09/ /92LevA^-t l40-m'-is -DcNpu P I 0 u; "rcz- NX,-,I- PO T-P'TECH EDITORS*JDMain09/24/92SC:OEAB*RLDennig09/24/92:SPLBCEMcCrcken092/9209 3-1n I -KcBC:OEABAEChaffee09/4&/92BC:OGCBGHMarcus09/ /92Or? oSSC.l1er- Duesc,?/Xl/q;;410a.inCovCO LV V% ecceLpCAPt"XU I4posh4aDSCet.C do Lue g;Al CLL4e.?.-
V- IN 92-71September 29, 992This event at Barseback is directly applicable to an earlier study conductedby the NRC. That study evaluated the potential for displaced thermalinsulation to form debris and to be drawn to the sump screen. The results ofthe study are documented in "Containment Sump Performance," NUREG-0897,Revision 1, dated March 1984. The NRC concluded that the risk associated withthe sump clogging concern did not warrant backfitting of domestic plants.However, based on the Barsebdck event and NUREG-0897, Revision 1, thisconclusion is being reevaluated.This information notice requires no specific action or written response. Ifyou have any questions about the information in this notice, please contactthe technical contact listed below or the appropriate Office of NuclearReactor Regulation (NRR) project manager.Charles E. Rossi, DirectorDivision of Operational Events AssessmentOffice of Nuclear Reactor RegulationTechnical contact: Robert L. Dennig, NRR(301) 504-1156List of Recently Issued NRC Information Notices


===Attachment:===
you have any questions about the information
Document Name: 92-71.IN*SEE PREVIOUS CONCURRENCES*OEAB:DOEA:NRR*SC/OEAB:DOEA:NRRRWWoodruff RLDennig09/24/92 09/24/92DOEA:NRR C/OGCB:DOEA:NRR*RPB:ADMCERossi GHMarcus)GLK- TechEd09/ /92 09/,S/92 &o 09/24/24*C/OEAB:DOEA:NRR*C/SPLB:DST:NRR CEP/OIPAChaffee CEMcCracken AKenneke09/ /92 09/ /92 09/ /92 K>-NRCIN 92-XXSeptember xx, 1991 technical contact listed below or the appropriate Office of Nuclear ReactorRegulation project manager.Charles E. Rossi, DirectorDivision of OperationalEvents AssessmentOffice of Nuclear Reactor Regulation
 
in this notice, please contact
 
the technical contact listed below or the appropriate
 
Reactor Regulation (NRR) project manager.                Office of Nuclear
 
(arles        si, Director
 
Division of Operational Events Assessment
 
Office of Nuclear Reactor Regulation
 
Technical contact:  Robert L. Dennig, NRR
 
(301) 504-1156 Attachment:  List of Recently Issued NRC Information Notices
 
Attachment
 
IN 92-71 September 30, 1992 LIST OF RECENTLY ISSUED
 
NRC INFORMATION NOTICES
 
Information                                    Date of
 
Notice No.              Subject                Issuance  Issued to
 
92-70          Westinghouse Motor-Operated    09/25/92  All holders of OLs or CPs
 
Valve Performance Data                    for nuclear power reactors.
 
Supplied to Nuclear Power
 
Plant Licensees
 
92-69          Water Leakage from Yard        09/22/92  All holders of OLs or CPs
 
Area Through Conduits                      for nuclear power reactors.
 
Into Buildings
 
91-29,          Deficiencies Identified        09/14/92  All holders of OLs or CPs
 
Supp. 1        During Electrical Dis-                    for nuclear power reactors.
 
tribution System Func- tional Inspections
 
92-68          Potentially Substandard        09/10/92  All holders of OLs or CPs
 
Slip-On, Welding Neck,                    for nuclear power reactors.
 
and Blind Flanges
 
92-67          Deficiency in Design            09/10/92  All holders of OLs or CPs
 
Modifications to Ad-                      for nuclear power reactors.
 
dress Failures of
 
Hiller Actuators Upon
 
A Gradual Loss of
 
Air Pressure
 
92-66          Access Denied to NRC            09/01/92  All holders of OLs or CPs
 
Inspectors at Five Star                    for nuclear power reactors
 
Products, Inc. and                        and all recipients of
 
Construction Products                      NUREG-0040, "Licensee, Con- Research, Fairfield,                      tractor and Vendor Inspec- Connecticut                                tion Status Report" (White.
 
Book).
 
92-65          Safety System Problems          09/03/92  All holders of OLs or CPs
 
Caused by Modifications                    for nuclear power reactors.
 
That Were Not Adequately
 
Reviewed and Tested
 
92-64          Nozzle Ring Settings            08/28/92  All holders of-OLs or CPs
 
on Low Pressure Water-                    for nuclear power reactors.
 
Relief Valves
 
OL = Operating License
 
CP = Construction Permit
 
K>                                        <YIN 92-71 September 30, 1992 This event at Barseback is directly applicable to an earlier study conducted
 
by the NRC. That study evaluated the potential for displaced thermal
 
insulation to form debris and to be drawn to the sump screen. The results of
 
the study are documented in "Containment Sump Performance," NUREG-0897, Revision 1, dated March 1984. The NRC concluded that the risk associated with
 
the sump clogging concern did not warrant backfitting of domestic plants.
 
However, based on the BarsebAck event, this conclusion is being reevaluated.
 
This information notice requires no specific action or written response. If
 
you have any questions about the information in this notice, please contact
 
the technical contact listed below or the appropriate Office of Nuclear
 
Reactor Regulation (NRR) project manager.
 
Original Signed by
 
Charles E. Rossi
 
Charles E. Rossi, Director
 
Division of Operational Events Assessment
 
Office of Nuclear Reactor Regulation
 
Technical con itact:    Robert L. Dennig, NRR
 
(301) 504-1156 Attachment:     List of Recently Issued NRC Information Notices
 
Document Name: 92-71.IN
 
*SEE PREVIOUS CONCURRENCES
 
DO                  *C/OGCB:DOEA:NRR*RPB:ADM
 
C                    GHMarcus        TechEd
 
09/; 92              09/28/92        09/24/24
  *OEAB:DOEA:NRR*SC/OEAB:DOEA:NRR        *C/OEAB:DOEA:NRR*C/SPLB:DST:NRR      ICEP/OIPw
 
RWWoodruff      RLDennig              AChaffee            CEMcCracken      AKenqeke
 
09/24/92       09/24/92              09/k8/92              09/1r/92        09/dg/92 V CEp/aze
 
SC~hLAt_- Jest)
  o1i  A                    e- rw W.
 
,L .I
 
4.4a
 
-- - I
 
4 ago,.            ?.        e
 
,      am ASCo
 
NRCIN 92-XX
 
September xx, 1991 documented in "Containment Sump Performance," NUREG-0897, Revision 1, dated March
 
1984. The NRC concluded that the risk associated with the sump clogging concern
 
did not warrant backfitting of domestic plants. However, based on the Barseback
 
event and NUREG-0897, Revision 1, this conclusion is being reevaluated.
 
This information notice requires no specific action or written response. If you
 
have any question about the information in this notice, please contact the
 
technical contact listed below or the appropriate Office of Nuclear Reactor
 
Regulation project manager.-
                                                      Charles E. Rossi, Director
 
Division of Operational
 
Events Assessment
 
Office of Nuclear Reactor Regulation
 
Technmical Contact:      Robert L. Dennig, NRR
 
(301) 504-1156 Attachment:
              1.    List of Recently Issued Information Notices
 
* See previous page for concurrence.
 
CONCURRENCE:
              OEAB            TECH EDITORS SC:OEAB            :SPLB    BC:OEAB        BC:OGCB
 
*RWWoodruff      *JDMain        *RLDennig    CEMcCrcken  AEChaffee      GHMarcus
 
09/24/92        09/24/92      09/24/92        092/92    09/4&/92        09/ /92 D:DOEA          Or?    o
 
SSC.l1er-      Dues
 
09    3-1 CERossi
 
09/    /92 c,?/Xl/q;;
                                                              nI -Kc
 
410a.in
 
LevA^-t l40-m'-
                                        CovCO
 
LV    ecc
 
V%
is-  DcNpu I P0u;"r                                                        t.C do            Lue  g;
                                      eLpCAPt"XU  I4 posh 4  aDSCe                          Al CLL4e.?.-
cz-    NX,-,I-  PO    T-P'
 
V- IN 92-71 September 29, 1992 This event at Barseback is directly applicable to an earlier study conducted
 
by the NRC. That study evaluated the potential for displaced thermal
 
insulation to form debris and to be drawn to the sump screen. The results of
 
the study are documented in "Containment Sump Performance," NUREG-0897, Revision 1, dated March 1984. The NRC concluded that the risk associated with
 
the sump clogging concern did not warrant backfitting of domestic plants.
 
However, based on the Barsebdck event and NUREG-0897, Revision 1, this
 
conclusion is being reevaluated.
 
This information notice requires no specific action or written response. If
 
you have any questions about the information in this notice, please contact
 
the technical contact listed below or the appropriate Office of Nuclear
 
Reactor Regulation (NRR) project manager.
 
Charles E. Rossi, Director
 
Division of Operational Events Assessment
 
Office of Nuclear Reactor Regulation
 
Technical con tact:  Robert L. Dennig, NRR
 
(301) 504-1156 Attachment:  List of Recently Issued NRC Information Notices
 
Document Name: 92-71.IN
 
*SEE PREVIOUS CONCURRENCES
 
DOEA:NRR       C/OGCB:DOEA:NRR*RPB:ADM
 
CERossi        GHMarcus)GLK- TechEd
 
09/ /92         09/,S/92 &o       09/24/24
*OEAB:DOEA:NRR*SC/OEAB:DOEA:NRR *C/OEAB:DOEA:NRR*C/SPLB:DST:NRR CEP/OIP
 
RWWoodruff      RLDennig          AChaffee        CEMcCracken     AKenneke
 
09/24/92       09/24/92         09/ /92         09/ /92          09/ /92
 
K>-
                                                                NRCIN 92-XX
 
September xx, 1991 technical contact listed below or the appropriate Office of Nuclear Reactor
 
Regulation project manager.
 
Charles E. Rossi, Director
 
Division of Operational
 
Events Assessment
 
Office of Nuclear Reactor Regulation


===Technical Contact:===
===Technical Contact:===
Robert L. Dennig, NRR(301) 504-1156


===Attachment:===
===Robert L. Dennig, NRR===
1. List of Recently Issued Information NoticesCONCTRRENCE:OEAB W'RWWoodruff09 5/92D : DOEACERossi09/ /92TECH EDITORirgaln Pl09/2,1/9209/; f92BC: SPLUCEMcCracken09/ /92BC: OEKBAEChaffee09/ /92BC: KCBGHMarcus09/ /92410.in}}
                      (301) 504-1156 Attachment:
1. List of Recently Issued Information Notices
 
CONCTRRENCE:
OEAB W'     TECH EDITOR                  BC: SPLU    BC: OEKB      BC: KCB
 
RWWoodruff    irgaln Pl                  CEMcCracken  AEChaffee    GHMarcus
 
09 5/92      09/2,1/92      09/; f92      09/ /92      09/ /92      09/ /92 D: DOEA
 
CERossi
 
09/ /92
                                                                            410.in}}


{{Information notice-Nav}}
{{Information notice-Nav}}

Latest revision as of 03:22, 24 November 2019

Partial Plugging of Suppression Pool Strainers at a Foreign BWR
ML031200327
Person / Time
Site: Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, Nine Mile Point, Palisades, Palo Verde, Perry, Indian Point, Fermi, Kewaunee, Catawba, Harris, Wolf Creek, Saint Lucie, Point Beach, Oyster Creek, Watts Bar, Hope Creek, Grand Gulf, Cooper, Sequoyah, Byron, Pilgrim, Arkansas Nuclear, Three Mile Island, Braidwood, Susquehanna, Summer, Prairie Island, Columbia, Seabrook, Brunswick, Surry, Limerick, North Anna, Turkey Point, River Bend, Vermont Yankee, Crystal River, Haddam Neck, Ginna, Diablo Canyon, Callaway, Vogtle, Waterford, Duane Arnold, Farley, Robinson, Clinton, South Texas, San Onofre, Cook, Comanche Peak, Yankee Rowe, Maine Yankee, Quad Cities, Humboldt Bay, La Crosse, Big Rock Point, Rancho Seco, Zion, Midland, Bellefonte, Fort Calhoun, FitzPatrick, McGuire, LaSalle, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant  Entergy icon.png
Issue date: 09/30/1992
From: Rossi C
Office of Nuclear Reactor Regulation
To:
References
IN-92-071, NUDOCS 9209290014
Download: ML031200327 (7)
v • d • e


_~K)

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555 September 30, 1992 NRC INFORMATION NOTICE 92-71: PARTIAL PLUGGING OF SUPPRESSION POOL

STRAINERS AT A FOREIGN BWR

Addressees

All holders of operating licenses or construction permits for nuclear power

reactors.

Purpose

The U.S. Nuclear Regulatory Commission (NRC) is issuing this information

notice to alert addressees to the potential-for loss of emergency core cooling

systems (ECCS) that was identified as a result of an event at a Swedish

boiling water reactor (BWR). It is expected that recipients will review thel

information for applicability to their facilities and consider actions, as

appropriate, to avoid similar problems. However, suggestions contained in

this information notice are not NRC requirements; therefore, no specific

action or written response is required.

Description of Circumstances

On July 28, 1992, Sydkraft AB, the utility licensed by the Swedish regulatory

agency for the BarsebAck nuclear power plant, was restarting Unit 2 after the

annual outage. While the reactor was at 1 or 2 percent power and at 435 psi, a leaking pilot valve caused a safety valve for the reactor vessel to open.

This valve discharges directly to the drywell. Reactor scram, high pressure

safety injection, core spray, and containment spray systems initiated

automatically in response to the event. Steam from the open safety valve, impinging on thermally-insulated equipment, dislodged 440 pounds of metal- jacketed, mineral wool. An estimated 220 pounds of insulating material was

washed into the suppression pool. Two of five strainers on the suction side

of the ECCS pumps were in service and became partially plugged with mineral

wool. Plugging caused pressure to decrease significantly across the strainers

and caused indications of cavitation in one pump in about an hour after the

event began. The operators successfully back flushed the strainers and shut

down the reactor without additional problems.

Discussion

In the safety analysis for Unit 2 of the Barsebdck plant, the licensee

concluded that the strainers would not require back flushing during the first

10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> after a loss-of-coolant accident. Because of the event of July 28, the Swedish regulatory agency required Barseback Unit 2 and four other units

of similar design to remain shut down until this problem is resolved.

9209290014 e

III

IN 92-71 September 30, 1992 This event at BarsebAck is directly applicable

by the NRC. That study evaluated the potential to an earlier study conducted

insulation to form debris and to be drawn to for displaced thermal

the study are documented in "Containment Sump the sump screen. The results of

Revision 1, dated March 1984. The NRC concluded Performance," NUREG-0897, that the risk associated with

the sump clogging concern did not warrant backfitting

However, based on the Barsebdck event, this of domestic plants.

conclusion is being reevaluated.

This information notice requires no specific

action or written response. If

you have any questions about the information

in this notice, please contact

the technical contact listed below or the appropriate

Reactor Regulation (NRR) project manager. Office of Nuclear

(arles si, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical contact: Robert L. Dennig, NRR

(301) 504-1156 Attachment: List of Recently Issued NRC Information Notices

Attachment

IN 92-71 September 30, 1992 LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information Date of

Notice No. Subject Issuance Issued to

92-70 Westinghouse Motor-Operated 09/25/92 All holders of OLs or CPs

Valve Performance Data for nuclear power reactors.

Supplied to Nuclear Power

Plant Licensees

92-69 Water Leakage from Yard 09/22/92 All holders of OLs or CPs

Area Through Conduits for nuclear power reactors.

Into Buildings

91-29, Deficiencies Identified 09/14/92 All holders of OLs or CPs

Supp. 1 During Electrical Dis- for nuclear power reactors.

tribution System Func- tional Inspections

92-68 Potentially Substandard 09/10/92 All holders of OLs or CPs

Slip-On, Welding Neck, for nuclear power reactors.

and Blind Flanges

92-67 Deficiency in Design 09/10/92 All holders of OLs or CPs

Modifications to Ad- for nuclear power reactors.

dress Failures of

Hiller Actuators Upon

A Gradual Loss of

Air Pressure

92-66 Access Denied to NRC 09/01/92 All holders of OLs or CPs

Inspectors at Five Star for nuclear power reactors

Products, Inc. and and all recipients of

Construction Products NUREG-0040, "Licensee, Con- Research, Fairfield, tractor and Vendor Inspec- Connecticut tion Status Report" (White.

Book).

92-65 Safety System Problems 09/03/92 All holders of OLs or CPs

Caused by Modifications for nuclear power reactors.

That Were Not Adequately

Reviewed and Tested

92-64 Nozzle Ring Settings 08/28/92 All holders of-OLs or CPs

on Low Pressure Water- for nuclear power reactors.

Relief Valves

OL = Operating License

CP = Construction Permit

K> <YIN 92-71 September 30, 1992 This event at Barseback is directly applicable to an earlier study conducted

by the NRC. That study evaluated the potential for displaced thermal

insulation to form debris and to be drawn to the sump screen. The results of

the study are documented in "Containment Sump Performance," NUREG-0897, Revision 1, dated March 1984. The NRC concluded that the risk associated with

the sump clogging concern did not warrant backfitting of domestic plants.

However, based on the BarsebAck event, this conclusion is being reevaluated.

This information notice requires no specific action or written response. If

you have any questions about the information in this notice, please contact

the technical contact listed below or the appropriate Office of Nuclear

Reactor Regulation (NRR) project manager.

Original Signed by

Charles E. Rossi

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical con itact: Robert L. Dennig, NRR

(301) 504-1156 Attachment: List of Recently Issued NRC Information Notices

Document Name: 92-71.IN

  • SEE PREVIOUS CONCURRENCES

DO *C/OGCB:DOEA:NRR*RPB:ADM

C GHMarcus TechEd

09/; 92 09/28/92 09/24/24

  • OEAB:DOEA:NRR*SC/OEAB:DOEA:NRR *C/OEAB:DOEA:NRR*C/SPLB:DST:NRR ICEP/OIPw

RWWoodruff RLDennig AChaffee CEMcCracken AKenqeke

09/24/92 09/24/92 09/k8/92 09/1r/92 09/dg/92 V CEp/aze

SC~hLAt_- Jest)

o1i A e- rw W.

,L .I

4.4a

-- - I

4 ago,.  ?. e

, am ASCo

NRCIN 92-XX

September xx, 1991 documented in "Containment Sump Performance," NUREG-0897, Revision 1, dated March

1984. The NRC concluded that the risk associated with the sump clogging concern

did not warrant backfitting of domestic plants. However, based on the Barseback

event and NUREG-0897, Revision 1, this conclusion is being reevaluated.

This information notice requires no specific action or written response. If you

have any question about the information in this notice, please contact the

technical contact listed below or the appropriate Office of Nuclear Reactor

Regulation project manager.-

Charles E. Rossi, Director

Division of Operational

Events Assessment

Office of Nuclear Reactor Regulation

Technmical Contact: Robert L. Dennig, NRR

(301) 504-1156 Attachment:

1. List of Recently Issued Information Notices

  • See previous page for concurrence.

CONCURRENCE:

OEAB TECH EDITORS SC:OEAB :SPLB BC:OEAB BC:OGCB

  • RWWoodruff *JDMain *RLDennig CEMcCrcken AEChaffee GHMarcus

09/24/92 09/24/92 09/24/92 092/92 09/4&/92 09/ /92 D:DOEA Or? o

SSC.l1er- Dues

09 3-1 CERossi

09/ /92 c,?/Xl/q;;

nI -Kc

410a.in

LevA^-t l40-m'-

CovCO

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cz- NX,-,I- PO T-P'

V- IN 92-71 September 29, 1992 This event at Barseback is directly applicable to an earlier study conducted

by the NRC. That study evaluated the potential for displaced thermal

insulation to form debris and to be drawn to the sump screen. The results of

the study are documented in "Containment Sump Performance," NUREG-0897, Revision 1, dated March 1984. The NRC concluded that the risk associated with

the sump clogging concern did not warrant backfitting of domestic plants.

However, based on the Barsebdck event and NUREG-0897, Revision 1, this

conclusion is being reevaluated.

This information notice requires no specific action or written response. If

you have any questions about the information in this notice, please contact

the technical contact listed below or the appropriate Office of Nuclear

Reactor Regulation (NRR) project manager.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical con tact: Robert L. Dennig, NRR

(301) 504-1156 Attachment: List of Recently Issued NRC Information Notices

Document Name: 92-71.IN

  • SEE PREVIOUS CONCURRENCES

DOEA:NRR C/OGCB:DOEA:NRR*RPB:ADM

CERossi GHMarcus)GLK- TechEd

09/ /92 09/,S/92 &o 09/24/24

  • OEAB:DOEA:NRR*SC/OEAB:DOEA:NRR *C/OEAB:DOEA:NRR*C/SPLB:DST:NRR CEP/OIP

RWWoodruff RLDennig AChaffee CEMcCracken AKenneke

09/24/92 09/24/92 09/ /92 09/ /92 09/ /92

K>-

NRCIN 92-XX

September xx, 1991 technical contact listed below or the appropriate Office of Nuclear Reactor

Regulation project manager.

Charles E. Rossi, Director

Division of Operational

Events Assessment

Office of Nuclear Reactor Regulation

Technical Contact:

Robert L. Dennig, NRR

(301) 504-1156 Attachment:

1. List of Recently Issued Information Notices

CONCTRRENCE:

OEAB W' TECH EDITOR BC: SPLU BC: OEKB BC: KCB

RWWoodruff irgaln Pl CEMcCracken AEChaffee GHMarcus

09 5/92 09/2,1/92 09/; f92 09/ /92 09/ /92 09/ /92 D: DOEA

CERossi

09/ /92

410.in


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