Information Notice 1992-85, Potential Failures of Emergency Core Cooling Systems Caused by Foreign Material Blackage

Potential Failures of Emergency Core Cooling Systems Caused by Foreign Material Blackage

ML031190717
Person / Time
Site:	Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, Mcguire, 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, 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, 05000419, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant, Crane
Issue date:	12/23/1992
From:	Grimes B Office of Nuclear Reactor Regulation
To:
References
IN-92-085, NUDOCS 9212170209
Download: ML031190717 (16)

-

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C.

20555

December 23, 1992

NRC INFORMATION NOTICE 92-85:

POTENTIAL FAILURES OF EMERGENCY CORE COOLING

SYSTEMS CAUSED BY FOREIGN MATERIAL BLOCKAGE

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 failure of emergency core cooling

systems (ECCS) caused by foreign material blockage.

It is expected that

recipients will review the 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

H. B. Robinson Unit 2

On August 23, 1992, while the H. B. Robinson Nuclear Plant was in mode 4, hot

shutdown, plant personnel were performing an operations surveillance test of

the B safety injection (SI) pump. This test found that the recirculation flow

was 20 percent lower than it had been when it was last measured on July 12,

1992.

Prompted by the resident inspector, the Carolina Power and Light

Company (the licensee) retested this pump on August 24, 1992, and found no

recirculation flow.

The licensee also tested the A SI pump and found the

recirculation flow was 10 percent lower than when it was last measured.

The

licensee declared both pumps inoperable and took the unit to cold shutdown.

On August 25, 1992, the licensee opened the B SI pump recirculation line and

removed a single piece of white plastic, about the size of a nickel, from the

inline orifice.

Previously, on July 8, 1992, the licensee had declared the B SI pump

inoperable after a quarterly inservice inspection surveillance test found that

it was producing a recirculation flow of 11.4 Liters [3 gallons] per minute, rather than the required 132.5 Liters [35 gallons] per minute.

On July 9,

1992, the licensee shut down the plant to determine the cause of the low flow.

The licensee removed the recirculation line for the B SI pump and found that

debris was obstructing the inline orifice.

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IN 92-85 December 23, 1992 On July 12, 1992, after flushing the B SI pump and verifying that

recirculation flows for both SI pumps were acceptable, the licensee returned

the unit to service.

The licensee also tested all other ECCS pumps that could

have had contact with foreign material.

The licensee believed, prior to plant

startup, that all debris had been removed.

Point Beach Unit 2

On September 28, 1992, the Wisconsin Electric Power Company (the licensee)

performed an ASME Section XI quarterly test of containment spray pumps and

valves. During the test, the licensee noted that the discharge pressure for

the A train containment spray pump was zero and that the pump was making an

abnormal noise.

The test was stopped and the pump was declared inoperable.

Upon disassembly of the pump, a foam rubber plug was found blocking the

impeller suction.

The licensee removed the plug and retested the pump.

The

test was successfully completed and the pump was declared operable.

Discussion

The licensee at H. B. Robinson determined that the foreign material found in

the SI system was a plastic material that had been used during a modification

of the Residual Heat Removal (RHR) system performed in March through

June 1992.

The plastic material is manufactured by DuPont and the trade name

is Delrin-AF.

At the time of the RHR modification, the plastic material had

been cut into-four 23=centimeter [9-inch]-diameter,-circular pieces for use-as

weld purge dams. However, after completing the modification, the licensee did

not account for two of the four pieces.

Delrin-AF decomposes at RCS system

conditions because of reaction with the water and thermal degradation. The

licensee suspected that the purge dam pieces broke,. entered the RHR piping

after breaking, and migrated into the refueling water storage tank (RWST) and

SI header during initial cavity draindown.

The licensee sent divers with cameras into the RWST to inspect for the

plastic.

The divers found three fragments of Delrin-AF plastic and also other

pieces of miscellaneous debris.

The location and size of the recovered

Delrin-AF material agrees with the material migration theory since all of the

pieces were larger than those recovered from the B SI pump in July and August.

The licensee inspected orifices for the SI pump minimum flow recirculation

lines and also visually inspected piping, tanks, and components to find and

remove any foreign material.

Also, the licensee evaluated the potential

effect on other ECCS equipment and concluded that the ECCS equipment would

continue to be operable and reliable.

a

IN 92-85 December 23, 1992 The licensee for Point Beach Unit 2 reviewed plant records and determined that

the plug was most likely left in the piping after modifications were made to

install full flow test lines in the RHR, containment spray and safety

injection systems, during the 1991 refueling outage.

The NRC reviewed the

event and determined that one train of the safety injection system piping was

rendered inoperable in the recirculation mode because of the presence of the

plug.

This condition had continued for about a year and was caused by

inadequate foreign material exclusion controls during the system modifications

made in the previous outage.

The presence of small debris may not be detected by operational or post

modification testing since blockages may not appear immediately.

However, small debris may migrate into areas with smaller cross sections where the

debris could collect and cause blockage after extended operation.

These

examples illustrate the consequences of failure to ensure accountability of

all materials that are used when safety systems are opened and to perform

cleanliness checks of all affected areas prior to system closure.

Related Generic Communication

On November 21, 1989, the NRC issued Information Notice (IN) 89-77, "Debris In

Containment Emergency Sumps and Incorrect Screen Configurations," which

addressed problems that could result from debris in containment emergency

sumps.

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.

rnan K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contact:

Eric Benner, NRR

(301) 504-1171 Attachment:

List of Recently Issued NRC Information Notices

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IN 92-85 December 23,

1992 Page I of 1

LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information

Notice No.

Subject

92-84

Release of Patients

Treated with Temporary

Implants

88-23,

Potential for Gas

Supp. 4 Binding of High-Pres- sure Safety Injection

Pumps during A Design

Basis Accident

92-83

Thrust Limits for

Limitorque Actuators

and Potential Over- stressing of Motor-

Operated Valves

92-82 Results of Thermo-Lag

330-1 Combustibility

Testing

92-81

Potential Deficiency

of Electrical Cables

with Bonded Hypalon

Jackets

92-80

Results of Thermo-Lag

330-1 Combustibility

Testing

92-79 Non-Power Reactor

Emergency Event Response

92-78

Piston to Cylinder

Liner Tin Smearing on

Cooper-Bessemer KSV

Diesel Engines

Vate of

Issuance

Issued to

12/17/92

All Nuclear Regulatory

Comnission Medical

(

Licensees.

12/18/92

All holders of OLs or CPs

for nuclear power reactors

12/17/92

All holders of OLs or CPs

for nuclear power reactors

12/15/92

All holders of OLs or CPs

for nuclear power reactors

12/11/92

All holders of OLs or CPs

for nuclear power reactors.

12/07/92

All holders of OLs or CPs

for nuclear power reactors.

12/01/92 All holders of OLs or CPs(

for test and research

reactors.

11/30/92

All holders of OLs or CPs

for nuclear power reactors.

DL - Operating License

CP - Construction Permit

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IN 92-XX

December xx, 1992 The licensee for Point Beach Unit 2 reviewed plant records and determined that

the plug was most likely left in the piping after modifications were made to

install full flow test lines-in the residual heat removal (RHR), containment

spray and safety injection systems, during the 1991 refueling outage. The NRC

reviewed the event and determined that one train of the safety injection

system piping was rendered inoperable in the recirculation mode because of the

presence of the plug.

The NRC issued a Notice of Violation and Proposed

Imposition of Civil Penalty in the amount of $75,000.

This violation, which

was classified at Severity Level III, continued for about a year and was

caused by inadequate foreign material exclusion controls during the system

modifications made in the previous outage.

The presence of small debris may not be detected by operational or post

modification testing since blockages may not appear immediately.

However, small debris may migrate into areas with smaller cross sections where the

debris could collect and cause blockage after extended operation.

Whenever

safety systems are opened, it is important to ensure accountability of any

materials that are used and to perform cleanliness checks of all affected

areas prior to system closure.

Related Generic Communication

On November 21, 1989, the NRC issued Information Notice (IN) 89-77, "Debris In

Containment Emergency Sumps and Incorrect Screen Configurations," which

addressed problems that could result from debris in containment emergency

sumps.

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.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contact: Eric Benner, NRR

(301) 504-1171 Attachment:

List of Recently Issued NRC Information Notices

• SEE PREVIOUS CONCURRENCE

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IN 92-XX

December xx, 1992

The licensee for Point Beach Unit 2 reviewed plant records and determined that

the plug was most likely left in the piping after modifications were made to

install full flow test lines in the residual heat removal (RHR), containment

spray and safety injection systems, during the 1991 refueling outage. The NRC

reviewed the event and determined that one train of the safety injection

system piping was rendered inoperable in the recirculation mode because of the

presence of the plug. The NRC is issuing a Notice of Violation and Proposed

Imposition of Civil Penalty in the amount of $75,000. This violation, which

has been classified at Severity Level III, continued for about a year and was

caused by inadequate foreign material exclusion controls during the system

modifications made in the previous outage.

The presence of small debris may not be detected by operational or post

modification testing since blockages may not appear immediately. However, small debris may migrate into areas with smaller cross sections where the

debris could collect and cause blockage after extended operation. Whenever

safety systems are opened, it is important to ensure accountability of any

materials that are used and to perform cleanliness checks of all affected

areas prior to system closure.

Related Generic Communication

On November 21, 1989, the NRC issued Information Notice (IN) 89-77, "Debris In

Containment Emergency Sumps and Incorrect Screen Configurations," which

addressed problems that could result from debris in containment emergency

sumps.

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.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contact: Eric Benner, NRR

(301) 504-1171 Attachment:

List of Recently Issued NRC Information Notices

• SEE PREVIOUS CONCURRENCE

OEAB:DORS

ASC/OEAB:DORS

ADM:RPB

PM:PD2-1:DRPE

DGarcia*

AGautam*

JMain*

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10/07/92

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IN 92-XX

December xx, 1992

pieces of miscellaneous debris. The location and size of the recovered

Delrin-AF material agrees with the material migration theory since all of the

pieces were larger than those recovered from the B SI pump in July and August.

The licensee inspected orifices for the SI pump minimum flow recirculation

lines, and visually inspected piping, tanks, and components to find and remove

any foreign material.

Also, the licensee evaluated the potential effect on

other ECCS equipment and concluded that the ECCS equipment would continue to

be operable and reliable.

7-1- t-

The staff notes thatl$resence of small debris may not be detected by

operational or post-modification testing since blockages may not appear

immediately.

However, small debris may migrate into areas with smaller cross

sections where the debris can collect and cause blockage after extended

operation. Whenever safety systems are opened, it is important to ensure

accountability of any materials that are used and to perform'cleanliness

checks of all affected areas prior to system closure.

Related Generic Communication

On November 21, 1989, the NRC issued Information Notice (IN) 89-77, "Debris In

Containment Emergency Sumps and Incorrect Screen Configurations," which

addressed problems that could result from debris in containment emergency

sumps.

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.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical cor

Attachment:

• SEE PREVIOUS

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Eric Benner, NRR

(301) 504-1171

List of Recently Issued NRC Information Notices

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November xx, 1992 Related Generic Communication

On November 21, 1989, the NRC issued Information Notice (IN) 89-77, 'Debris In

Containment Emergency Sumps and Incorrect Screen Configurations," in which it

discussed problems that could result from debris found in containment

emergency sumps.

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.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contacts:

D. Garcia, NRR

(301) 504-1170

Attachment:

List of Recently Issued NRC Information Notices

• SEE PREVIOUS CONCURRENCE

OEAB:DORS

DGarcia*

10/07/92 ASC/OEAB:DORS

AGautam*

10/14/92 ADM:RPB

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IN 92-XX

October xx, 1992 Related Generic Communication

On November 21, 1989, the NRC issued Information Notice (IN) 89-77, "Debris In

Containment Emergency Sumps and Incorrect Screen Configurations," in which it

discussed problems that could result from debris found in containment

emergency sumps.

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.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contacts:

D. Garcia, NRR

(301) 504-1170

Attachment:

List of Recently Issued NRC Information Notices

• SEE PREVIOUS CONCURRENCE

OEAB:DORS

DGarcia*

10/07/92 ASC/OEAB:DgRS

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IN 92-XX

October xx, 1992 Related Generic Communication

On November 21, 1989, the NRC issued Information Notice (IN) 89-77, 'Debris In

Containment Emergency Sumps and Incorrect Screen Configurations,' in which it

discussed problems that could result from debris found in containment

emergency sumps.

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.

Brian K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contacts:

Denise M. Garcia, NRR

(301) 504-1170

Attachment:

List of Recently Issued NRC Information Notices

• SEE PREVIOUS

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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 contacts:

Denise M. Garcia, NRR

(301) 504-1171 Attachment:

List of Recently Issued NRC Information Notices

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UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C.

20555

December 23, 1992

NRC INFORMATION NOTICE 92-85: POTENTIAL FAILURES OF EMERGENCY CORE COOLING

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 failure of emergency core cooling

systems (ECCS) caused by foreign material blockage. It is expected that

recipients will review the 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

H. B. Robinson Unit 2

On August 23, 1992, while the H. B. Robinson Nuclear Plant was in mode 4, hot

shutdown, plant personnel were performing an operations surveillance test of

the B safety injection (SI) pump.

This test found that the recirculation flow

was 20 percent lower than it had been when it was last measured on July 12,

1992.

Prompted by the resident inspector, the Carolina Power and Light

Company (the licensee) retested this pump on August 24, 1992, and found no

recirculation flow. The licensee also tested the A SI pump and found the

recirculation flow was 10 percent lower than when it was last measured.

The

licensee declared both pumps inoperable and took the unit to cold shutdown.

On August 25, 1992, the licensee opened the B SI pump recirculation line and

removed a single piece of white plastic, about the size of a nickel, from the

inline orifice.

Previously, on July 8, 1992, the licensee had declared the B SI pump

inoperable after a quarterly inservice inspection surveillance test found that

it was producing a recirculation flow of 11.4 Liters [3 gallons] per minute, rather than the required 132.5 Liters [35 gallons] per minute.

On July 9,

1992, the licensee shut down the plant to determine the cause of the low flow.

The licensee removed the recirculation line for the B SI pump and found that

debris was obstructing the inline orifice.

9212

0209

<-2

<off92-85 December 23, 1992 On July 12, 1992, after flushing the B SI pump and verifying that

recirculation flows for both SI pumps were acceptable, the licensee returned

the unit to service. The licensee also tested all other ECCS pumps that could

have had contact with foreign material. The licensee believed, prior to plant

startup, that all debris had been removed.

Point Beach Unit 2

On September 28, 1992, the Wisconsin Electric Power Company (the licensee)

performed an ASME Section XI quarterly test of containment spray pumps and

valves. During the test, the licensee noted that the discharge pressure for

the A train containment spray pump was zero and that the pump was making an

abnormal noise. The test was stopped and the pump was declared inoperable.

Upon disassembly of the pump, a foam rubber plug was found blocking the

impeller suction. The licensee removed the plug and retested the pump. The

test was successfully completed and the pump was declared operable.

Discussion

The licensee at H. B. Robinson determined that the foreign material found in

the SI system was a plastic material that had been used during a modification

of the Residual Heat Removal (RHR) system performed in March through

June 1992. The plastic material is manufactured by DuPont and the trade name

is Delrin-AF. At the time of the RHR modification, the plastic material had

been cut into four 23-centimeter (9-inch] diameter, circular pieces for use as

weld purge dams.

However, after completing the modification, the licensee did

not account for two of the four pieces. Delrin-AF decomposes at RCS system

conditions because of reaction with the water and thermal degradation. The

licensee suspected that the purge dam pieces broke, entered the RHR piping

after breaking, and migrated into the refueling water storage tank (RWST) and

SI header during initial cavity draindown.

The licensee sent divers with cameras into the RWST to inspect for the

plastic. The divers found three fragments of Delrin-AF plastic and also other

pieces of miscellaneous debris. The location and size of the recovered

Delrin-AF material agrees with the material migration theory since all of the

pieces were larger than those recovered from the B SI pump in July and August.

The licensee inspected orifices for the SI pump minimum flow recirculation

lines and also visually inspected piping, tanks, and components to find and

remove any foreign material. Also, the licensee evaluated the potential

effect on other ECCS equipment and concluded that the ECCS equipment would

continue to be operable and reliable.

IN 92-85 December 23, 1992 The licensee for Point Beach Unit 2 reviewed plant records and determined that

the plug was most likely left in the piping after modifications were made to

install full flow test lines in the RHR, containment spray and safety

injection systems, during the 1991 refueling outage.

The NRC reviewed the

event and determined that one train of the safety injection system piping was

rendered inoperable in the recirculation mode because of the presence of the

plug. This condition had continued for about a year and was caused by

inadequate foreign material exclusion controls during the system modifications

made in the previous outage.

The presence of small debris may not be detected by operational or post

modification testing since blockages may not appear immediately.

However, small debris may migrate into areas with smaller cross sections where the

debris could collect and cause blockage after extended operation. These

examples illustrate the consequences of failure to ensure accountability of

all materials that are used when safety systems are opened and to perform

cleanliness checks of all affected areas prior to system closure.

Related Generic Communication

On November 21, 1989, the NRC issued Information Notice (IN) 89-77, "Debris In

Containment Emergency Sumps and Incorrect Screen Configurations," which

addressed problems that could result from debris in containment emergency

sumps.

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.

rnan K. Grimes, Director

Division of Operating Reactor Support

Office of Nuclear Reactor Regulation

Technical contact:

Eric Benner, NRR

(301) 504-1171 Attachment:

List of Recently Issued NRC Information Notices

l

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Attachment

IN 92-85

December 23, 1992 LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information

Date of

Notice No.

Subject

Issuance

Issued to

92-84

88-23, Supp. 4

92-83

92-82

92-81

92-80

Release of Patients

Treated with Temporary

Implants

Potential for Gas

Binding of High-Pres- sure Safety Injection

Pumps during A Design

Basis Accident

Thrust Limits for

Limitorque Actuators

and Potential Over- stressing of Motor-

Operated Valves

Results of Thermo-Lag

330-1 Combustibility

Testing

Potential Deficiency

of Electrical Cables

with Bonded Hypalon

Jackets

Results of Thermo-Lag

330-1 Combustibility

Testing

Non-Power Reactor

Emergency Event Response

Piston to Cylinder

Liner Tin Smearing on

Cooper-Bessemer KSV

Diesel Engines

12/17/92

12/18/92

12/17/92

12/15/92

12/11/92

12/07/92

12/01/92

11/30/92

All Nuclear Regulatory

Commission Medical

Licensees.

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 test and research

reactors.

All holders of OLs or CPs

for nuclear power reactors.

92-79

92-78 OL = Operating License

CP = Construction Permit