Information Notice 1998-25, Loss of Inventory from Safety-Related Closed-Loop Cooling Water Systems

Loss of Inventory from Safety-Related Closed-Loop Cooling Water Systems

ML031050129
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, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant
Issue date:	07/08/1998
From:	Roe J Office of Nuclear Reactor Regulation
To:
References
IN-98-025, NUDOCS 9807010287
Download: ML031050129 (9)

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555-0001 July 8,1998 NRC INFORMATION NOTICE 98-25: LOSS OF INVENTORY FROM SAFETY-RELATED,

CLOSED-LOOP COOLING WATER SYSTEMS

Addressees

All holders of operating licenses for nuclear power reactors, except those licensees who have

permanently ceased operations and have certified that fuel has been permanently removed

from the reactor vessel.

Purpose

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

addressees to potential inoperability of safety-related, closed-loop cooling water systems due to

loss of inventory from excessive leakage combined with the absence of a reliable and timely

annunciation and/or makeup system. 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

Palisades

On January 1, 1998, Palisades Nuclear Plant was operating at 100 percent power when a leak

from the safety-related, dosed-loop component cooling water (CCW) system at the 'A'

radioactive waste evaporator distillate cooler Increased from about 100 ml/min to about

757 I/min (200 gpm,) which was more than the makeup capacity to the CCW system. The leak

emptied the CCW surge tank and resulted in a reduction in the normal CCW discharge header

pressure from about 929 kPa (135 psia) to 777 kPa (113 psia). The licensee identified the

source of the leak and isolated the applicable components within about 15 minutes. The

licensee did not observe any abnormal component temperatures and did not Identify any effect

on the primary coolant pump seals. After Isolating the leak, the operators refilled and vented

the CCW system and returned It to service.

Calvert Cliffs I

In September 1993, at Calvert Cliffs Nuclear Power Plant, Unit 1, a 91 Vmin (24 gpm) leak

occurred In the safety-related, closed-loop service water system. The flow path for the makeup

system from the demineralized water and condensate systems Is not seismically qualified and

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IN 98-25 July 8, 1998 the transfer pumps are not powered from a Class 1E source. Therefore, the service water

system could have been rendered Inoperable in less than an hour in the event of a loss of

offsite power or a seismic event based on the available volume in the surge tank.

Perry 1 On July 2, 1993, during a performance test at Perry Nuclear Power Plant, Unit 1, the licensee

determined that inadequate procedural direction for setting motor-operated valve limit switches

and mechanical stops resulted In a leak rate of 946 Vmin (250 gpm) through the Isolation valve

between the non-safety-related and the safety-related portions of the emergency closed cooling

water (ECCW) system. This leakage would have exceeded the seven-day, design basis

Inventory of the ECCW surge tank. In addition, under specific conditions (i.e., loss-of-offsite

power concurrent with the single failure of the Division 2 diesel generator), both ECCW trains

could have failed.

San Onofre 2

In March 1988, at the San Onofre Nuclear Generating Station, Unit 2, the licensee determined

that the safety-related, dosed-loop CCW system may have operated outside Its design basis for

leakage before a 1984 design modification. In 1983, the licensee realized that the original basis

(CCW leakage of .537 Vmin [.142 gpm]) for having only a non-safety-related and a non- seismically qualified makeup system could not be maintained. The licensee concluded that on

the basis of the magnitude of the potential leakage, the ability to mitigate the consequences of

postulated accidents could have been impaired.

Discussion

At most boiling-water and pressurized-water reactor plants, a safety-related, closed-loop

cooling water system is provided to supply cooling water to safety-related components, including components that may carry radioactive or potentially radioactive fluids. This

closed-loop cooling water system provides a monitored, intermediate barrier between the

radioactive or potentially radioactive fluid and the environment. The closed-loop cooling water

system usually transfers Its heat to the ultimate heat sink through a safety-related open-loop

cooling water system. Inmost cases, the safety-related, dosed-loop cooling water systems are

required to operate during normal, shutdown, and accident conditions.

Many of these closed-loop cooling water systems also have portions that are not safety related

and not designed to seismic Category I requirements. A failure Inthese non-safety-related

portions of the system during normal operation or as a result of a seismic event can lead to

excessive loss of Inventory from the safety-related portion of the system. Therefore, Inaddition

to postulated leaks inthe safety-related portions of the system, postulated leaks or breaks In

the non-safety-related portions also have the potential to result Inan excessive loss of inventory

from the safety-related portions of the system.

An excessive loss of inventory from the dosed-loop system, without makeup, could prevent it

from performing its safety function and may result Inthe plant being outside Its design basis.

Components that could be adversely affected are plant dependent and could include the reactor

IN 98-25 July 8, 1998 Page 3 6f 4 coolant pumps and seals, emergency core cooling system pumps, containment coolers, containment spray pumps, emergency diesel generators, safety-related room coolers, residual

heat removal heat exchangers, suppression pool coolers, and other safety-related equipment.

The events previously discussed underscore the possibility that an excessive leakage from the

safety-related, cdosed-loop cooling water system could render it Inoperable under one of the

following conditions:

1. Non-safety-related annunciation for low Inventory failing to alert the operators.

2. Inadequate bases for low Inventory alarm setpoint resulting In insufficient time for

operator action.

3. Non-safety-related or non-seismically qualified makeup supply and inadequate

bases for Its startup setpoint with no procedures available for providing makeup

from a seismic category I source.

4. Non-conservative assumptions about the leakage resulting in actual leakage that

exceeds the makeup capacity.

5. Insufficient surge or makeup tank capacity to accommodate expected leakage

from the system for an extended period (7 days recommended by Standard

Review Plan Section 9.2.2, *Reactor Auxiliary Cooling Water Systems.")

Some of the actions taken by the above-mentioned licensees to address this issue are as

follows:

At Palisades, the licensee reported that the low-level alarm setpoint was changed. The

licensee also changed the makeup actuation setpoint to 41 percent. The licensee

revised Off-Normal Procedures to Include appropriate immediate actions. The licensee

also performed a root cause analysis to determine the cause of the leak and conducted

a programmatic review to prevent the system from leaking In the future.

At Calvert Cliffs, the licensee wrote procedures for a cross-connect path by way of

hoses from the safety-related saltwater system to the service water system for extreme

emergencies. In addition, precautionary limits have been incorporated into plant

procedures to ensure that engineering and maintenance personnel are informed before

leakage approaches the specified operability limit.

At Perry, the licensee readjusted the limit switches and mechanical stops for Isolation

valves. The licensee revised the applicable procedure to provide the requisite level of

direction for setting limittorque switches and adjusting mechanical stops.

At San Onofre, the licensee had already made a design modification In 1984 to add the

capability of supplying makeup water from a seismically qualified source.

> B2IN 98-25 July 8, 1998 Related Generic Communications

NRC INFORMATION NOTICE 93-92: PLANT IMPROVEMENTS TO MITIGATE COMMON

DEPENDENCIES IN COMPONENT COOLING WATER SYSTEMS,' dated December 7, 1993.

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

questions about the information In this notice, please contact one of the technical contacts listed

below or the appropriate Office of Nuclear Reactor Regulation (NRR) project manager.

,/5Jack W. Roe Acting Director

(7/ Division of Reactor Program Management

V/ Office of Nuclear Reactor Regulation

Technical contacts: Rick Khan, NRR

301-415-1152 e-mail: tmk@nrc.gov

William T. LeFave, NRR

301-415-3285 e-mail: wtl2@nrc.gov

Attachment: List of Recently Issued NRC Information Notices

x\_Attachment

IN 98-25 July 8, 1998 LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information Date of

Notice No. Subject Issuance Issued to

98-24 Stem Binding in Turbine 7/08/98 All holders of operating licenses

Governor Valves in Reactor for nuclear power reactors except

Core Isolation Cooling (RCIC) those who have permanently

and Auxiliary Feedwater (AFW) ceased operation and have

Systems certified that fuel has been

permanently removed from the

reactor vessel

98-23 Crosby Relief Valve Setpoint 6/26/98 All holders of operating licenses

Drift Problems Caused by for pressurized water reactors

Corrosion of the Guide Ring (PWRs), except those licensees

permanently ceased operations

and have certified that fuel has

been permanently removed from

the reactor vessel

98-22 Deficiencies Identified 6/23/98 All holders of operating licenses

During NRC Design for nuclear power reactors, except

Inspections those licensees who have

permanently ceased operations

and have certified that fuel has

been permanently removed from

the vessel

98-21 Potential Deficiency of 6/4/98 All holders of operating licenses

Electrical Cable/Connection for nuclear power reactors, except

Systems those licensees who have

permanently ceased operations

and have certified that fuel has

been permanently removed from

the reactor vessel.

OL = Operating License

CP = Construction Permit

IN 98-25 June 8, 1998 Related Generic Communications

NRC INFORMATION NOTICE 93-92: PLANT IMPROVEMENTS TO MITIGATE COMMON

DEPENDENCIES IN COMPONENT COOLING WATER SYSTEMS," dated December 7, 1993.

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

questions about the information in this notice, please contact one of the technical contacts listed

below or the appropriate Office of Nuclear Reactor Regulation (NRR) project manager.

[Original signed by]

Jack W. Roe, Acting Director

Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical contacts: Rick Khan, NRR

301-415-1152 e-mail: tmk@nrc.gov

William T. LeFave, NRR

301-415-3285 e-mail: wtl2@nrc.gov

Attachment: List of Recently Issued NRC Information Notices ,47 # - A

DOCUMENT NAME: S:/DRPMSEC\98-25.IN 'ip

• See previous concurrence 7/1 To receive a copy of this document, Indicate Inthe box C=Copy wlo attachment/enclosure E=Copy with attachment/enclosure N Icopy

I-I

OFFICE PECB I (TECH

CONTACT

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NAME TKhan* IWLefave* LMarsh* JStolz* JRoe*/DBM for

DATE 06/18/98 06/18/98 06/22/98 06/25/98 06/30/98

[OFFICIAL RECORD COPY]

IN9 x

June xx, 1998 Related Generic Communications

NRC INFORMATION NOTICE 93-92: 'PLANT IMPROVEMENTS TO MITIGATE COMMON

DEPENDENCIES INCOMPONENT COOLING WATER SYSTEMS," dated December 7,1993.

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

questions about the information in this notice, please contact one of the technical contacts listed

below or the appropriate Office of Nuclear Reactor Regulation (NRR) project manager.

Jack W. Roe, Acting Director

Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical contacts: Rick Khan, NRR

301-415-1152 e-mail: tmk@nrc.gov

William T. LeFave, NRR

301-415-3285 e-mail: wtl2@nrc.gov

Attachment: List of Recently Issued NRC Information Notices

DOCUMENT NAME: g:/tmk:fin98O5tx.tkl

• See previous concurrence

To receive a copy of this document, Indicate In the box C=Copy wlo attachmentlenclosure E=Copy with attachmentlenclosure N = No copy

OFFICE I

PECB I (TECH

CONTACT

) I C:SPLB I C:CB .I (A)D:DRPM4 11 NAME TKhan* WLefave* ILMarsh* JS+rt l JRoeAt t

DATE 06/18/98 06/18/98 06/22/98 I /98 I3 498 kIt

[OFFICIAL RECORD COPY] W

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IN 98-xx

June xx, 1998 Page$ of J5 Related Generic Communications

NRC INFORMATION NOTICE 93-92: "PLANT IMPROVEMENTS TO MITIGATE COMMON

DEPENDENCIES IN COMPONENT COOLING WATER SYSTEMS," dated December 7, 1993.

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

questions about the information in this notice, please contact one of the technical contacts listed

below or the appropriate Office of Nuclear Reactor Regulation (NRR) project manager.

Jack W. Roe, Acting Director

Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical contacts: Rick Khan, NRR

301-415-1152 e-mail: tmk@nrc.gov

William T. LeFave, NRR

301-415-3285 e-mail: wt2@nrc.gov

Attachment: List of Recently Issued NRC Information Notices

DOCUMENT NAME: g:/tmk:in9805tx.tkl

• See previous concurrence

Tn receive a mnnv of this document. Indicate In the box C=Conv wfo attachmentfenclosure E=CoDy with attachmentfenclosure N = No copy

OFFICE PECB l (TECH

CONTACT

) I C:SPLB I C:PECB (A)D:DRPM I

NAME TKhan* WLefave* LMarsh* JStolz JRo e

DATE 06/18/98 06/18/98 06/22/98 I /98 / /98

[OFFICIAL RECORD COPY]

62-56

IN 98-xx

June xx, 1998 Related Generic Communications

1. NRC INFORMATION NOTICE 93-92: "PLANT IMPROVEMENTS TO MITIGATE

COMMON DEPENDENCIES IN COMPONENT COOLING WATER SYSTEMS," dated

December 7, 1993.

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

questions about the information in this notice, please contact one of the technical contacts listed

below or the appropriate Office of Nuclear Reactor Regulation (NRR) project manager.

Jack W: Roe, Acting Director

Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical contacts: Rick Khan, NRR

301-415-1152 e-mail: tmk@nrc.gov

William T. LeFave, NRR

301-415-3285 e-mail: wtl2@nrc.gov

Attachment: List of Recently Issued NRC Information Notices

DOCUMENT NAME: g:/tmk:/in9805tx.tkl

[

To receive a copy of this document, Indicate in the box C=Copy wlo attachmentlenclosure E=Copy with attachment/enclosure N = No copy

OFFICET PECB AE

NAME

DATE

TKhan

_____98 _

(TECH

CONTACT

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WLefave 0

44/_98 I C:SPLB

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[OFFICIAL RECORD COPY]