Information Notice 1989-54, Potential Overpressurization of the Component Cooling Water System

Potential Overpressurization of the Component Cooling Water System

ML031180685
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, 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, 05000000, Zimmer, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant
Issue date:	06/23/1989
From:	Rossi C Office of Nuclear Reactor Regulation
To:
References
IN-89-054, NUDOCS 8906190114
Download: ML031180685 (7)

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C.

20555

June 23, 1989

NRC INFORMATION NOTICE NO. 89-54: POTENTIAL OVERPRESSURIZATION OF THE

Addressees

All holders of operating licenses or construction permits for nuclear power

reactors.

Purpose

This information notice Is being provided to alert addressees to potential

problems resulting from failure of the component cooling water tubing within

the thermal barrier heat exchanger of a reactor coolant pump.

It is expected

that recipients will review the information for applicability to their facili- ties and consider actions, as appropriate, to avoid similar problems.

However, suogestions contained in this information notice do not constitute NRC require- ments; therefore, no specific action or written response is required.

Description of Circumstances

On May 15, 1989, the licensee for Surry Power Station informed the NRC of a

design deficiency in the component cooling water (CCW) system.

The deficiency

results from underdesign in relief capacity of the CCW lines connected to the

thermal barrier heat exchangers on the reactor coolant pumps. The reactor

coolant pumps at Surry were manufactured by Westinghouse and rely on heat

removal by the CCW system in conjunction with seal injection for reactor

coolant pump seal and lower radial bearing. cooling. The reactor coolant pump

motors are also cooled by component cooling water.

Component cooling water flows through the thermal barrier heat exchangers

within 1/2-inch ID tubes.

At the request of the licensee for Surry, Westing- house calculated the maximum reactor coolant flow rate that could occur from a

break in a thermal barrier tube. Westinghouse calculated the flow rate into

the CCW system assuming a double ended break of the 1/2-inch ID tube. The

calculation modeled the reactor coolant flow upstream of the break and the flow

out the break into the CCW system. An inleakage of approximately 275 gpm was

predicted.

The CCW piping adjacent to the reactor coolant pumps at Surry is of schedule

160 carbon steel and is designed to withstand full reactor system pressure.

The lower-pressure sections of the CCW system within containment and within the

auxiliary building are designed for 150 psig.

In the event of reactor coolant

i

T

77 --

IN 89-54 June 23, 1989 system inleakage, the low-pressure sections of CCW piping are protected from

overpressure by a check valve on the upstream side of the reactor coolant pump

thermal barrier and by a fast-closing, air-operated valve on the downstream

side.

The isolation valve is designed to close on a high CCW flow signal.

In

addition, a relief valve which is located on the upstream side of the thermal

barrier is designed to open at 150 psig. The licensee determined that this

protection was not adequate to protect the low-pressure parts of the CCW system

from overpressure if the calculated inleakage (approximately 275 gpm) were to

occur.

The air-operated isolation valve is not safety related and the relief

valve is only designed to pass 167 gpm.

Isolation valves are provided on the

CCW lines outside the containment building, but these are not designed to

withstand reactor system pressure.

Failure to isolate the leak inside contain- ment or to provide adequate relieving capacity could lead to an unisolatable

reactor coolant leak outside the containment building. The licensee is in- stalling additional relief capacity on the CCW lines upstream and downstream of

the reactor coolant thermal barrier heat exchangers at both Surry plants.

In July 1984, Westinghouse notified the NRC (in accordance with 10 CFR Part 21)

of a similar problem involving potential overpressure of CCW systems at 18 plants with CCW systems designed by Westinghouse. These plants were equipped

with a CCW surge tank vent valve that would close automatically on high radio- activity in the CCW system. Westinghouse stated that in the event that reactor

coolant inleakage resulted in closure of the vent valve, the CCW system could -

be overpressurized downstream of the CCW pumps. At the time of the 10 CFR Part

- 21 n"tification, Westinghouse Tndicated that a thermal ba-rrieFrtube rupture

would result in a leak rate of approximately 260 gpm. Westinghouse recommended

several corrective measures designed to ensure continual venting of the surge

tank, thereby preventing overpressurization of the low-pressure CCW system.

The CCW system at Surry was not designed by Westinghouse and Surry was, there- fore, not included with the 18 plants identified by Westinghouse in the 10 CFR

Part 21 notification.

In view of the potential for CCW over-pressurization

identified at Surry, other plant owners may wish to evaluate protection of

low-pressure CCW piping from overpressure in the event of failure of the

reactor coolant pump thermal barrier tubing.

No specific action or written response is required by this information notice.

If you have any questions about this matter, please contact one of the techni- cal contacts listed below or the Regional Administrator of the appropriate

regional office.

har

Rs

ssij

~reto

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: William Lefave, NRR

(301) 492-0862

Walton Jensen, NRR

(301) 492-1190

Attachment:

List of Recently Issued NRC Information Notices

Attachment

IN 89-54

June 23, 1989 LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information

Date of

Notice No.

Subject

Issuance

Issued to

89-53

Rupture of Extraction

Steam Line on High

Pressure Turbine

6/13/89

All holders of OLs

or CPs for nuclear

power reactors.

88-46, Supp. 3

89-52

89-51

Licensee Report of

Defective Refurbished

Circuit Breakers

Potential Fire Damper

Operational Problems

Potential Loss of Required

Shutdown Margin During

Refueling Operations

6/8/89

6/8/89

5/31/89

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.

88-88,

-

Supp. 1

Degradation of Westinghouse

--ARD Relays--

5/31/89

__

All holders of OLs

-

or CPs for-nucleare

power reactors.

89-50

89-49

89-48

89-47

89-46

Inadequate Emergency

Diesel Generator Fuel

Supply

Failure to Close Service

Water Cross-Connect

Isolation Valves

Design Deficiency in the

Turbine-Driven Auxiliary

Feedwater Pump Cooling

Water System

Potential Problems With

Worn or Distorted Hose

Clamps on Self-Contained

Breathing Apparatus

Confidentiality of

Exercise Scenarios

5/30/89

5/22/89

5/22/89

5/18/89

5/11/89

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

fuel facilities.

All holders of licenses

for fuel cycle facilities

and byproduct material

licensees having an

approved emergency

response plan.

OL = Operating License

CP = Construction Permit

IN 89-54 June 23, 1989 system inleakage, the low-pressure sections of CCW piping are protected from

overpressure by a check valve on the upstream side of the reactor coolant pump

thermal barrier and by a fast-closing, air-operated valve on the downstream

side. The isolation valve is designed to close on a high CCW flow signal.

In

addition, a relief valve which is located on the upstream side of the thermal

barrier is designed to open at 150 psig. The licensee determined that this

protection was not adequate to protect the low-pressure parts of the CCW system

from overpressure if the calculated inleakage (approximately 275 gpm) were to

occur. The air-operated isolation valve is not safety related and the relief

valve is only designed to pass 167 gpm.

Isolation valves are provided on the

CCW lines outside the containment building, but these are not designed to

withstand reactor system pressure.

Failure to isolate the leak inside contain- ment or to provide adequate relieving capacity could lead to an unisolatable

reactor coolant leak outside the containment building. The licensee is in- stalling additional relief capacity on the CCW lines upstream and downstream of

the reactor coolant thermal barrier heat exchangers at both Surry plants.

In July 1984, Westinghouse notified the NRC (in accordance with 10 CFR Part 21)

of a similar problem involving potential overpressure of CCW systems at 18 plants with CCW systems designed by Westinghouse. These plants were equipped

with a CCW surge tank vent valve that would close automatically on high radio- activity in the CCW system. Westinghouse stated that in the event that reactor

coolant inleakage resulted in closure of the vent valve, the CCW system could

be overpressurized downstream of the CCW pumps. At the time of the 10 CFR Part

21 notification, Westinghouse indicated that a thermal barrier tube rupture

would result in a leak rate of approximately 260 gpm. Westinghouse recommended

several corrective measures designed to ensure continual venting of the surge

tank, thereby preventing overpressurization of the low-pressure CCW system.

The CCW system at Surry was not designed by Westinghouse and Surry was, there- fore, not included with the 18 plants identified by Westinghouse in the 10 CFR

Part 21 notification. In view of the potential for CCW over-pressurization

identified at Surry, other plant owners may wish to evaluate protection of

low-pressure CCW piping from overpressure in the event of failure of the

reactor coolant pump thermal barrier tubing.

No specific action or written response is required by this information notice.

If you have any questions about this matter, please contact one of the techni- cal contacts listed below or the Regional Administrator of the appropriate

regional office.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts: William Lefave, NRR

(301) 492-0862

Walton Jensen, NRR

(301) 492-1190

Attachment:

List of Recently Issued NRC Information Notices

• SEE PREVIOUS CONCURRENCES

06/ft89

• EAB:NRR

• EAB:NRR *TECH:ED *NRR:SLPB

• C:DEST:NRR *C:EAB:NRR *C:O B:NRR

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WDLanning CHBerlinger

06/09/89

06/09/89 06/08/89 06/13/89

06/14/89

06/15/89

06/15/89

IN 89- June , 1989 v overpressure by a check valve on the upstream side of the reactor coolant

pumps and by a fast-closing, air-operated valve on the downstream side. The

isolation valve Is designed to close on a high CCW flow signal. In addition.

a relief valve which is located on the upstream side of the thermal barrier is

designed to open at 150 psig. The licensee determined that this protection

was not adequate to protect the low-pressure parts of the CCW system from

overpressure if the calculated inleakage (approximately 275 gpm) were to occur.

The air-operated isolation valve is not safety related and the relief valve is

only designed to pass 167 gpm.

Isolation valves are provided on the CCW lines

outside the containment building, but these are not designed to withstand

reactor system pressure. The licensee is installing additional relief capacity

on the CCW lines upstream and downstream of the reactor coolant thermal barrier

heat exchangers at both Surry plants.

In July 1984, Westinghouse notified the NRC (in accordance with 10 CFR Part 21)

of a similar problem involving potential overpressure of CCW systems at 18 plants with CCW systems designed by Westinghouse. These plants were equipped

with a CCW surge tank vent valve that would close automatically on high

radioactivity in the CCW system. Westinghouse stated that in the event

that reactor coolant inleakage resulted in closure of the vent valve, the CCW

system could be overpressurized downstream of the CCW pumps. At the time of

the 10 CFR Part 21 notification, Westinghouse indicated that a thermal barrier

tube rupture would result in a leak rate of approximately 260 gpm. Westinghouse

recommended several corrective measures designed to ensure continual venting of

the surge tank, thereby preventing overpressurization of the low-pressure CCW

system. The CCW system at Surry was not designed by Westinghouse and Surry

was, therefore, not included with the 18 plants identified by Westinghouse in the

10 CFR Part 21 notification. In view of the potential for CCW over- pressurization identified at Surry. other plant owners may wish to evaluate

protection of low-pressure CCW piping from overpressure in the event of

failure of the reactor coolant pump thermal barrier tubing.

No specific action or written response is required by this information notice.

If you have any questions about this matter, please contact one of the

technical contacts listed below or the Regional Administrator of the

appropriate regional office.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts William Lefave, NRR

(301) 492-0862

Walton Jensen, NRR

(301) 492-1190

Attachment: List of Recently Issued NRC Information Notices

• SEE PREVIOUS CONCURRENCES

• EAB:NRR

• EAB:NRR *TECH:ED *NRR:SLPB

• C:DEST:NRR *C:EAB:NRR C:OGCB:NRR

WJensen:db RLobel

BLefave

LShao

WDLanning CHBerlinger

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IN 89- June , 1989

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< overpressure by a check valve on the upstream side of the reactor coolant

pumps and by a fast-closing, air-operated valve on the downstream side. The

Isolation valve is designed to close on a high CCVI flow signal.

In addition, a relief valve which is located on the upstream side of the thermal barrier is

designed to open at 150 psig. The licensee determined that this protection

was not adequate to protect the low-pressure parts of the CCW system from

overpressure if the calculated inleakage (approximately 275 gpm) were to occur.

The air-operated Isolation valve is not safety related and the relief valve is

only designed to pass 167 gpm.

Isolation valves are provided on the CCW lines

outside the containment building, but these are not designed to withstand

reactor system pressure. The licensee is installing additional relief capacity

on the CCW lines upstream and downstream of the reactor coolant thermal barrier

heat exchangers at both Surry plants.

In July 1984, Westinghouse notified the NRC (in accordance with 10 CFR Part 21)

of a similar problem involving potential overpressure of CCW systems at 18 plants with CCW systems designed by Westinghouse. These plants were equipped

with a CCW surge tank vent valve that would close automatically on high

radioactivity in the CCW system.

Westinghouse stated that in the event

that reactor coolant inleakage resulted in closure of the vent valve, the CCW

system could be overpressurized downstream of the CCW pumps.

At the time of

the 10 CFR Part 21 notification, Westinghouse indicated that a thermal barrier

tube rupture would result in a leak rate of approximately 260 gpm. Westinghouse

recommended several corrective measures designed to ensure continual venting of

the surge tank, thereby preventing overpressurization of the low-pressure CCW

system.

The CCW system at Surry was not designed by Westinghouse and Surry was

therefore not included with the 18 plants Identified by Westinghouse in the

10 CFR Part 21 notification. In view of the potential for CCW over- pressurization identified at Surry, other plant owners may wish to evaluate

protection of low-pressure CCW piping from overpressure in the event of

failure of the reactor coolant pump thermal barrier tubing.

No specific action or written response is required by this information notice.

If you have any questions about this matter, please contact one of the

technical contacts listed below or the Regional Administrator of the

appropriate regional office.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts William Lefave, NRR

(301) 492-0862

Walton Jensen, NRR

(301) 492-1190

Attachment: List of Recently Is ued NRC Information No I

• SEE PREVIOUS CONCURRENCE

• EAB:NRR

EAB:NRR *TECH:ED NRR L B

T:NRR C: AB: VR C:OGCB:NRR

WJensen:db RLobel

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WDLann ng CHBerlinger

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IN 89- June , 1989 a CCW surge tank vent valve that would close automatically on high

radioactivity in the CCW system. Westinghouse stated that in the event

reactor coolant inleakage resulted in closure of the vent valve, that the CCW

system could be overpressurized overpressure downstream of the CCW pumps.

At the time of the 10 CFR 21 notification Westinghouse indicated that a

thermal barrier tube rupture would result in a leak rate of approximately

260 gpm. Westinghouse recommended several corrective measures designed to

ensure continual venting of the surge tank thereby preventing overpressurization

of the low pressure CCW system. The CCW system at Surry was not designed by

Westinghouse and Surry was therefore not included with the 18 plants identified

by Westinghouse in the 10 CFR 21 notification. Based on the potential for

CCW overpressurizatlon identified at Surry, other plant owners may wish to

evaluate protection of low pressure CCW piping from overpressure in the event

of reactor coolant pump thermal barrier tubing failure.

No specific action or written response is required by this Information Notice.

If you have any questions about this matter, please contact one of the

technical contacts listed below or the Regional Administrator of the

appropriate regional office.

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical Contacts William Lefave, NRR

(301) 492-0862

Walton Jensen, NRR

(301) 492-1190

Attachment:

List of Recently Issued NRC Information Notices

qL-

• SEE PREVIOUS CONCURRENCE

• EAB:NRR

EAB:NRR TECH:ED

NRR:SLPB C:DEST:NRR C:EAB:NRR C:OGCB:NRR

WJensen:db RLobel

BLefave

LShao

WDLanning CHBerlinger

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