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

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
Issue date:	09/30/1992
From:	Rossi C Office of Nuclear Reactor Regulation
To:
References
IN-92-071, NUDOCS 9209290014
Download: ML031200327 (7)

_~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

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, 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.(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 92-69 91-29, Supp.92-68 92-67 1 Westinghouse

Motor-Operated

Valve Performance

Data Supplied to Nuclear Power Plant Licensees Water Leakage from Yard Area Through Conduits Into Buildings Deficiencies

Identified

During Electrical

Dis-tribution

System Func-tional Inspections

Potentially

Substandard

Slip-On, Welding Neck, and Blind Flanges Deficiency

in Design Modifications

to Ad-dress Failures of Hiller Actuators

Upon A Gradual Loss of Air Pressure Access Denied to NRC Inspectors

at Five Star Products, Inc. and Construction

Products Research, Fairfield, Connecticut

Safety System Problems Caused by Modifications

That Were Not Adequately

Reviewed and Tested 09/25/92 09/22/92 09/14/92 09/10/92 09/10/92 09/01/92 09/03/92 08/28/92 All holders of OLs or CPs for nuclear power reactors.All holders of OLs or CPs for nuclear power reactors.All holders of OLs or CPs for nuclear power reactors.All holders of OLs or CPs for nuclear power reactors.All holders of OLs or CPs for nuclear power reactors.All holders of OLs or CPs for nuclear power reactors and all recipients

of NUREG-0040, "Licensee, Con-tractor and Vendor Inspec-tion Status Report" (White.Book).All holders of OLs or CPs for nuclear power reactors.All holders of -OLs or CPs for nuclear power reactors.92-66 92-65 92-64 Nozzle on Low Relief Ring Settings Pressure Water-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 List of Recently Issued NRC Information

Notices Attachment:

Document Name: 92-71.IN*SEE PREVIOUS CONCURRENCES

• OEAB:DOEA:NRR*SC/OEAB:DOEA:NRR

RWWoodruff

RLDennig 09/24/92 09/24/92 V CEp/aze SC~hLAt_-

Jest)o1i A e- ,L .I DO *C/OGCB:DOEA:NRR*RPB:ADM

C GHMarcus TechEd 09/; 92 09/28/92 09/24/24*C/OEAB:DOEA:NRR*C/SPLB:DST:NRR

ICEP/OIPw AChaffee CEMcCracken

AKenqeke 09/k8/92 09/1r/92 09/dg/92 ago,. 4 e , am ASCo-- -I rw W. 4.4a

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*RWWoodruff

09/24/92 D:DOEA CERossi 09/ /92 LevA^-t l40-m'-is -DcNpu P I 0 u; "r cz- NX,-,I- PO T-P'TECH EDITORS*JDMain 09/24/92 SC:OEAB*RLDennig 09/24/92:SPLB CEMcCrcken

092/92 09 3-1 n I -Kc BC:OEAB AEChaffee 09/4&/92 BC:OGCB GHMarcus 09/ /92 Or? o SSC.l1er- Dues c,?/Xl/q;;

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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 List of Recently Issued NRC Information

Notices Attachment:

Document Name: 92-71.IN*SEE PREVIOUS CONCURRENCES

• OEAB:DOEA:NRR*SC/OEAB:DOEA:NRR

RWWoodruff

RLDennig 09/24/92 09/24/92 DOEA:NRR C/OGCB:DOEA:NRR*RPB:ADM

CERossi GHMarcus)GLK-

TechEd 09/ /92 09/,S/92 &o 09/24/24*C/OEAB:DOEA:NRR*C/SPLB:DST:NRR

CEP/OIP AChaffee CEMcCracken

AKenneke 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'RWWoodruff

09 5/92 D : DOEA CERossi 09/ /92 TECH EDITOR irgaln Pl 09/2,1/92 09/; f92 BC: SPLU CEMcCracken

09/ /92 BC: OEKB AEChaffee 09/ /92 BC: KCB GHMarcus 09/ /92 410.in