Information Notice 1992-28, Inadequate Fire Suppression System Testing

Inadequate Fire Suppression System Testing
	ML031200404
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, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant, Crane
Issue date:	04/08/1992
From:	Rossi C; Office of Nuclear Reactor Regulation
To:	;
References
	IN-92-028, NUDOCS 9204020186
	Download: ML031200404 (8)
	v • d • e

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555

April 8, 1992 NRC INFORMATION NOTICE 92-28:

INADEQUATE FIRE SUPPRESSION SYSTEM TESTING

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 potential inadequate performance of carbon dioxide (CO2)

and Halon fire suppression systems caused by excessive leakage from the pro- tected enclosure or by deficient operation of the system's components. Limited

acceptance testing may not be adequate to identify these problems. 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 require- ments; therefore, no specific action or written response is required.

Background

In Section 50.48 of Title 10 of the Code of Federal Regulations, the NRC

established fire protection requirements for operating nuclear power plants.

This rule requires automatic and manual fire suppression systems to function so

that the capability to safely shut down the plant is ensured.

Many licensees

use total flooding CO2 and Halon fire suppression systems to protect systems

necessary for safe shutdown. In Branch Technical Position APCSB 9.5-1,

"Guidelines for Fire Protection for Nuclear Power Plants," the staff referenced

National Fire Protection Association (NFPA) standards, NFPA 12-1973, "Carbon

Dioxide Extinguishing Systems," and NFPA 12A-1973, "Halon 1301 Fire Extinguish- ing Systems." These standards emphasized the need to minimize leakage from the

enclosure in order to retain the fire suppressing agent for the required soak

time and the importance of thoroughly inspecting the fire suppression system to

ensure that it will operate properly. Licensees frequently use full discharge

tests to demonstrate that fire suppression systems perform properly and that

leakage from protected enclosures is acceptable.

Description of Circumstances

On February 23, 1988, the Connecticut Yankee Atomic Power Company, the licensee

for the Haddam Neck Power Plant, performed a full discharge test of the CO2 fire suppression system for the containment cable vault. The test results

indicated that the CO2 concentration within the cable vault failed to meet

NFPA 1242. "

ents.

Consequently, on February 27, the licensee declared the

M40201862O186

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IN 92-28 April 8, 1992 fire suppression system for the cable vault inoperable. The licensee deter- mined that the root cause of the failure was excessive leakage of CO from the

enclosure area through numerous unsealed electrical conduits in the lower level

of the cable vault.

These conduits were in the original plant design, but were

not considered in the design of the CO2 system.

While performing an inspection the week of April 3, 1989, at the Susquehanna

Steam Electric Station (Susquehanna), the NRC found a concern regarding the

adequacy of initial testing of the plant's CO2 fire suppression systems.

In 1982, the Pennsylvania Power and Light Company (PP&L), the licensee for

Susquehanna, had performed a full discharge test for one of seven areas pro- tected by automatic CO2 fire suppression systems. The test found that the

required concentration of CO2 was not maintained in the enclosure for the

required soak time. The test results may have been caused solely by the

failure of a temporary seal around an access door.

However, the licensee did

not perform additional testing to confirm the cause of the test failure. The

licensee then performed limited acceptance tests of the CO2 fire suppression

systems.

To address the NRC's concern, PP&L performed testing in the first quarter of

1990 using room pressurization to measure enclosure leakage and to determine a

projected agent retention time.

The licensee based the testing on the enclo- sure integrity procedure in Appendix B to NFPA 12A-1989. The test results

indicated that three of the seven areas included enclosures with leakage

greater than that which would ensure retention of the required CO2 concentrattogi-for-the-'requhtr-d-t-sbk tim6-.--T1eWfailure of these enclosures was

attributed to their small enclosed volume and the corresponding small allowable

leakage area.

In general, a smaller allowable leakage area should be expected

for small enclosures because of the higher ratio of boundary area to enclosed

volume.

On April 21, 1990, at the Catawba Nuclear Station (Catawba), an inadvertent

steam release actuated a CO2 fire suppression system. Although the fire

suppression system is designed to discharge to only one area at a time, the

three selector pilot valves installed in the system directed the CO2 discharge

to all three areas protected by the system. Duke Power Company, the licensee

for Catawba, investigated the incident and discovered that the solenoids

operating the three selector pilot valves were installed backwards. The

licensee determined that the required CO2 concentration could not be obtained

within the protected areas when the system discharged into more than one area

at a time. Therefore, the licensee declared the system inoperable. The

licensee attributed the improper solenoid installation, in part, to a

preoperational test procedure which did not adequately test the system for the

incorrectly installed components.

Discussion

Retaining an adequate concentration of fire suppressing agent for the required

soak time is important for enclosures containing equipment that could develop

"deep seated" fires.

In a study of deep seated cable fires, Sandia National

Laboratory determined that, for certain configurations of cables qualified to

Standard 383 of the Institute of Electrical and Electronic Engineers (IEEE), it

IN 92-28 April 8, 1992 was necessary to retain a 50X concentration of CO2 for a minimum soak time of

15 minutes to extinguish fully developed fires.

Sandia National Laboratory

documented the results of the study in NUREG/CR-3656, "Evaluation of Suppres- sion Methods for Electrical Cable Fires," dated October 1986.

Full discharge testing of CO2 fire suppression systems may present certain

hazards at operating nuclear power plants. These hazards include thermal shock

to safety-related components, uncontrolled electrostatic discharge, and hazards

to personnel from high concentrations of CO2.

Some licensees have used

alternative testing methods which avoid these hazards.

For example, the

licensee for the Vermont Yankee Atomic Power Station responded to the NRC's

concern regarding the adequacy of initial tests of the plant's fire suppression

systems by performing an alternative test that incorporated methodology from

the enclosure integrity procedure in Appendix B to NFPA 12A-1989.

That method- ology is conservative because the effects of the thermal expansion of the

mixture of CO2 and air are not included and a "worst case" distribution of

measured leakage area is assumed.

The licensee also performed a rigorous

engineering evaluation of the installed CO

system to verify that the system

would operate as designed to deliver a sufficient amount of Co2.

The testing described in Section 1-7.4 of NFPA 12A-1989 was developed to

alleviate concerns for both the cost and the environmental damage associated

with repeatedly performing full discharge tests of Halon fire suppression

systems.

The testing described in NFPA 12A provides an alternative method to

full discharge testing of Halon systems to demonstrate that the fire suppres- sion system and the enclosure function as designed.

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 contact:

S. R. Jones, NRR

(301) 504-2833 Attachment:

List of Recently Issued NRC Information Notices

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IN 92-28

April 8, 1992

Page I of I

LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information

Date of

Notice No.

Subject

Issuance

Issued to

92-27 Thermally Induced Acceler-

04/03/92

All holders of OLs or CPs

ated Aging and Failure of

for nuclear power reactors.

ITE/GOULD A.C. Relays Used

in Safety-Related Applic- ations

92-26 Pressure Locking of Motor-

04/02/92

All holders of OLs or CPs

Operated Flexible Wedge

for nuclear power reactors.

Gate Valves

92-25 Potential Weakness in

03/31/92

All holders of OLs or CPs

Licensee Procedures for A

for nuclear power reactors.

Loss of the Refueling

Cavity Water

92-24 Distributor Modification to

03/30/92

All holders of OLs or CPs

Certain Commercial-Grade

for nuclear power reactors.

Agastat Electrical Relays

92-23 Results of Validation Test-

03/27/92

All holders of OLs or CPs

ing of Motor-Operated Valve

for nuclear power reactors

Diagnostic Equipment

and all vendors of motor- operated valve (MOV) diag- nostic equipment.

92-22 Criminal Prosecution and

03/24/92 All holders of OLs or CPs

K

Conviction of Wrongdoing

for nuclear power reactors.

Committed by A Commercial-

Grade Valve Supplier

92-21 Spent Fuel Pool Reactivity

03/24/92

All holders of OLs or CPs

Calculations

for nuclear power reactors.

92-20

Inadequate Local Leak Rate

03/03/92

All holders of OLs or CPs

Testing

for nuclear power reactors.

92-19 Misapplication of Potter L

03/02/92

All holders of OLs or CPs

Brumfield NOR Rotary Relays

for nuclear power reactors.

OL - Operating License

CP

Construction Permit

I

IN 92-28 April 8, 1992 was necessary to retain a 50% concentration of CO2 for a minimum soak time of

15 minutes to extinguish fully developed fires.

Sandia National Laboratory

documented the results of the study in NUREG/CR-3656, "Evaluation of Suppres- sion Methods for Electrical Cable Fires," dated October 1986.

Full discharge testing of CO2 fire suppression systems may present certain

hazards at operating nuclear power plants. These hazards include thermal shock

to safety-related components, uncontrolled electrostatic discharge, and hazards

to personnel from high concentrations of CO2.

Some licensees have used

alternative testing methods which avoid these hazards.

For example, the

licensee for the Vermont Yankee Atomic Power Station responded to the NRC's

concern regarding the adequacy of initial tests of the plant's fire suppression

systems by performing an alternative test that incorporated methodology from

the enclosure integrity procedure in Appendix B to NFPA 12A-1989. That method- ology is conservative because the effects of the thermal expansion of the

mixture of CO2 and air are not included and a "worst case" distribution of

measured leakage area is assumed.

The licensee also performed a rigorous

engineering evaluation of the installed CO system to verify that the system

would operate as designed to deliver a sufficient amount of CO2.

The testing described in Section 1-7.4 of NFPA 12A-1989 was developed to

alleviate concerns for both the cost and the environmental damage associated

with repeatedly performing full discharge tests of Halon fire suppression

systems. The testing described in NFPA 12A provides an alternative method to

full discharge testing of Halon systems to demonstrate that the fire suppres- sion system and the enclosure function as designed.

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.

Orginal Signed by

Charles E. oRsi

Charles E. Rossi, Director

Division of Operational Events Assessment

Office of Nuclear Reactor Regulation

Technical contact:

S. R. Jones, NRR

(301)

504-2833 Attachment:

List of Recently Issued NRC Information Notices

Document Name:

IN 92-28

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PREVIOUS CONCURRENCES

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TechEd

02/21/92

02/24/92

03/02/92

03/26/92

02/21/92

IN 92-XX

March xx, 1992 15 minutes to extinguish fully developed fires.

Sandia National Laboratory

documented the results of the study in NUREG/CR-3656, "Evaluation of Suppres- sion Methods for Electrical Cable Fires," dated October 1986.

Full discharge testing of CO2 fire suppression systems may present certain

hazards at operating nuclear power plants. These hazards include thermal shock

to safety-related components, uncontrolled electrostatic discharge, and hazards

to personnel from high concentrations of CO2.

Some licensees have used

alternative testing methods which avoid these hazards.

For example, the

licensee for the Vermont Yankee Atomic Power Station responded to the NRC's

concern regarding the adequacy of initial tests of the plant's fire suppression

systems by performing an alternative test that incorporated methodology from

the enclosure integrity procedure in Appendix B to NFPA 12A-1989. That method- ology is conservative because the effects of the thermal expansion of the

mixture of CO2 and air are not included and a "worst case" distribution of

measured leakage area is assumed. The licensee also performed a rigorous