Information Notice 1999-05, Inadvertent Discharge of Carbon Dioxide Fire Protection System and Gas Migration

Inadvertent Discharge of Carbon Dioxide Fire Protection System and Gas Migration

ML031040494
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:	03/08/1999
From:	Matthews D Division of Regulatory Improvement Programs
To:
References
IN-99-005, NUDOCS 9903020265
Download: ML031040494 (8)

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF NUCLEAR REACTOR REGULATION

WASHINGTON, D.C. 20555-0001 March 8, 1999 NRC INFORMATION NOTICE 99-05: INADVERTENT DISCHARGE OF CARBON DIOXIDE

FIRE PROTECTION SYSTEM AND GAS MIGRATION

Addressees

All holders of licenses for nuclear power, research, and test reactors, and fuel cycle facilities.

Purpose

The U.S. Nuclear Regulatory Commission (NRC) is Issuing this Information notice to alert

addressees to potential personnel safety hazards and operational complications associated with

discharge of carbon dioxide (C02) fire protection systems. It Is expected that recipients will

review the Information for applicability to their facilities and consider actions, as appropriate.

However, suggestions contained Inthis Information notice are not NRC requirements; therefore, no specific action or written response to this notice Is required.

Background

At Duane Arnold Unit I on March 22, 1992 (LER 331/92-004), the licensee performed a special

test of the C02 fire suppression system In the cable spreading room. This test was conducted

to check corrective actions taken following a C02 discharge In 1990. At the time of this test, the reactor had been shutdown and defueled. As a result of this test, C02 had Intruded into the

control room; this Intrusion led to an unacceptable reduction In area oxygen level within a few

minutes. Oxygen levels of 17 percent (at chest level) and 15 percent (at floor level) were

recorded; these levels were below the plant acceptance criterion of 19.5 percent. Essential

control room personnel donned self-contained breathing apparatus (SCBA) and were able to

remain In the control room. The lowered oxygen levels were caused by increased pressure In

the cable spreading room which Is directly beneath the control room. Sealed penetrations

between the two rooms leaked under the high differential pressure.

On July 28, 1998, at the Idaho National Engineering and Environmental Laboratory, during

preparation for electrical system preventive maintenance, a high-pressure C02 fire suppression

system unexpectedly actuated. The room In which workers were located was filled instantly

with C02, creating whiteout conditions. Workers did not have the means of escaping safely.

Emergency exit training was not provided; exit pathways were not dear, and, emergency

breathing apparatus, exit pathway lighting, and emergency ventilation were not available. The

accident resulted In one fatality, several life-threatening Injuries, and significant risk to the

safety of the Initial rescuers. The Accident Investigation Board determined that since 1975 there have been a total of 63 deaths and 89 inJuries resulting from accidents Involiing the

discharge of C02 fire suppression systems.

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IN 99-05 March 8, 1999

Description of Circumstances

On January 15, 1999, at 5:49 p.m., with the plant at full power, an Inadvertent discharge of the

C02 fire suppression system occurred In the Millstone Unit 3 cable spreading room. At

Millstone 3, the cable spreading room is located Inthe control building directly below the control

room. The actuation was caused when a non-licensed plant equipment operator trainee In the

service building blew dust off a printed circuit board located In the cable spreading room C02 control panel. The panel Is located in the service building, not the control building. There were

no plant personnel In the cable spreading room at the time of the discharge. Shortly after the

discharge, C02 was found to have migrated down Into the swltchgear rooms located directly

below the cable spreading room. Approximately 37 minutes after initiation, the licensee used a

portable Instrument to measure the concentration of C02 In one of the Control Building

stairwells (which allows access to the control room, the cable spreading room and the

switchgear rooms). The reading was off-scale high Indicating that the C02 concentration was

in excess of 50,000 parts per million (ppm). The current NRC Regulatory Guide 1.78 recommended toxicity limit for C02 is 10,000 ppm'. On the basis of this Indication, the licensee

declared the area uninhabitable.

Approximately 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> after the C02 discharge, operators aligned the control building purge

system to remove C02 from the switchgear rooms. The switchgear rooms were selected for

purging first because they contained important plant equipment, such as the auxiliary shutdown

panel. The purge system Is a non-safety-related system designed to remove C02 and smoke

from various control building areas. Placing the purge system in service diverted air from the

control room to the switchgear rooms which lowered the pressure In the control room relative to

the cable spreading room. This lowering of pressure in the control room may have allowed

C02 from the cable spreading room to migrate up through penetrations Into the control room.

When the concentration of C02 reached 5000 ppm Inthe control room, the operators donned

self-contained breathing apparatus (SCBA) as required by their procedures. The concentration

of C02 Inthe control room reached a peak level In excess of 17,000 ppm before It began to

decrease. The operators wore SCBA for approximately 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> until the C02 was successfully

purged from the control room.

Discussion

A review of this event by the licensee Identified several design and personnel safety Issues.

The cable spreading room C02 system Is designed to automatically actuate In response to a

fire. The system is equipped with alarms to warn personnel In the cable spreading room of an

Impending discharge of C02 to allow time to evacuate the cable spreading room.. In response

lThe current NRC toxicity limit for C02, specified in Reg. Guide 1.78, is 10000 ppm. Plant

personnel exposed to C02 need to be protected by self contained breathing apparatus before this

concentration is reached. In the proposed revision to Reg. Guide 1.78, the toxicity limit for C02 was

raised to 40000 ppm. Whis new limit is based on the Immediately Dangerous to Life and Health (IDLE)

concentration of C02, established by the National Institute for Occupational Safety and Health (NIOSH).

IN 99-05 March 8, 1999 to several previous Inadvertent actuations, the licensee had previously modified automatic C02 fire protection systems In other areas of the plant so that they could only be actuated manually.

After the January 15, 1999 event, the licensee disabled the automatic function of the C02 system for the cable spreading room and Implemented appropriate compensatory measures.

The licensee Is evaluating permanent changes to avoid future Inadvertent C02 discharges.

The migration of C02 Into three separate fire zones may have adversely affected the operators'

ability to shut down the plant during a fire in the cable spreading room. A severe fire In the

cable spreading room may adversely affect the operators' ability to safely shut down the plant

from the control room. In the event that the operators are required to evacuate the control

room, plant procedures require operators to shutdown the plant from the auxiliary shutdown

panel and other panels which are located In the switchgear rooms. During this event, the C02 concentration at the auxiliary shutdown panel would prohibit access without SCBA.

In 1996 the licensee established a site wide fire brigade. In 1997, the licensee suspended the

formal SCBA training and qualification program for plant operators except those who were

members of the fire brigade. This determination was based on projected post-accident radiation

levels and Intrusion of toxic gases Into the control room from outside sources. However, this

determination failed to consider C02 a toxic gas as recommended In NRC Regulatory Guide

1.78. Fortunately, during this event, SCBA were available in the control room area and at

various other locations around the site. Although training and qualifications for all plant

operators were not current, all the plant operators that were on shift during the event had

previously been trained and qualified with the SCBA and consequently they were able to

perform their duties using the SCBA. To improve communication between the operators, the

licensee replaced the Unit 3 SCBA with SCBA from Unit 2 which had an improved type of radio

communication system. In addition, some of the operators did not have corrective lenses

which were compatible with the SCBA face masks. As an Immediate corrective action the

licensee re-qualified all plant operators for SCBA use. The licensee Is evaluating the need to

reinstate the SCBA qualification program for plant operators on a permanent basis. This

suspension of SCBA quarffication was for plant operators only and did not affect fire brigade

members who were trained and qualified.

The discharge of C02 set off a security alarm on the cable spreading room door. A security

officer was Instructed to check the door alarm but to not open the door. The guard entered the

stairwell and ascended the stairs to the cable spreading room. Upon approaching the cable

spreading room, the officer smelled wintergreen (which Is discharged with the C02 to produce

an odor for personnel safety) and was engulfed In a mist that he concluded was C02. The

officer held his breath and rapidly exited the building. The Uoensee's root cause team

recommended that procedures for isolating areas potentially affected by C02 be reviewed.

IN 99-05 March 8, 1999 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, the appropriate regional office, or the appropriate office of Nuclear Reactor

Regulation (NRR) Project Manager.

David B. Matthews, Director

Division of Regulatory Improvement Programs

Office of Nuclear Reactor Regulation

Technical contacts: Beth Korona, Region I Frank Amer, Region I

860-447-3170 610-337-5194 E-mail: bek(&nrc.aov E-mail: fiafnrc.aov

Chuck Petrone, NRR Peter S. Lee, NMSS

301-415-1027 301-415-8111 E-mail: cdp@nrc.gov E-mail: psll@nrc.gov

Attachments:

1. List of Recently Issued NMSS Information Notices

2. List of Recently Issued NRC Information Notices

Attachment I

IN 99-05 March 8, 1999 LIST OF RECENTLY ISSUED

NMSS INFORMATION NOTICES

Information Date of

Notice No. Subject Issuance Issued to

99-04 Unplanned Radiation Exposures 311/99 All radiography licensees.

to Radiographers, Resulting From

Failures to Follow Proper Radiation

Safety Procedures

99-03 Exothermic Reactions Invoking 1/29199 All operating uranium recovery

Dried Uranium Oxide Powder facilities that produce oxide

(Yellowcake) powder (U308) (yellowcake)

99-02 Guidance to Users on the 1121199 All medical licensees authorized to

Implementation of a New conduct brachytherapy

Single-Source Dose- treatments.

Calculation Formalism and Revised

Air-Kerma Strength Standard

for Iodine-125 Sealed Sources

99-01 Deterioration of High-Efficiency 1/20199 All holders of licences for nuclear

Particulate Air Fitters In a power, research and test reactors;

Pressurized Water Reactor and fuel cycle facilities.

Containment Fan Cooler Unit

98-33 NRC Regulations Prohibit 81298 All holders of a Nuclear

Regulatory Agreements that Restrict or Commission license

Discourage an Employee from

Participating In Protected Actvities

98-30 Effect of the Year 2000 8/12/98 All material and fuel cycle

Computer Problem on NRC licensees and certificate holders

Licensees and Certificate Holders

97-91 Recent Failure of Control 8110198 All industrial radiography

Supp. I Cables Used on Amersham licensees.

Model 660 Posilock Radiography

Systems

98-20 Problems With Emergency 6/3/98 All holders of operating licenses

Preparedness Respiratory for nuclear power reactors; non- Protection Programs power reactors; all fuel cycle and

material licensees required to

have an NRC-approved

emergency plan.

Attachment 2 IN 99-05 March 8, 1999 Page 1 of I

LIST OF RECENTLY ISSUED

NRC INFORMATION NOTICES

Information Date of

Notice No. Subject Issuance Issued to

99-04 Unplanned Radiation Exposures 311/99 All radiography licensees.

to Radiographers, Resulting From

Failures to Follow Proper Radiation

Safety Procedures

S9-03 Exothermic Reactions Involving 1/29199 All operating uranium recovery

Dried Uranium Oxide Powder facilities that produce oxide

(Yellowcake) powder (U30g) (yellowcake)

99-02 Guidance to Users on the 1121/99 All medical licensees authorized

Implementation of a New to conduct brachytherapy

Single-Source Dose- treatments.

Calculation Formalism and Revised

Air-Kerma Strength Standard

for Iodine-125 Sealed Sources

99-01 Deterioration of High-Efficiency 0112099 All holders of licenses for nuclear

Particulate Air Filters In a power, research and test reactors;

Pressurized Water Reactor and fuel cycle facilities.

Containment Fan Cooler Unit

9845 Cavitation Erosion of Letdown Line 12115198 All holders of operating licenses

Orifices Resulstin In Fatigue Cracking for nuclear power reactors, except

of Pipe Welds those that have permanently

ceased operations and have

certified that fuel has been

permanently removed from the

reactor.

98-44 Ten-year Inservice Inspection 12/10/98 All holder of operating licenses

(ISI) Program Update for Ucensees for nuclear power reactors, except

that Intend to Implement Risk-Informed those that have permanently

ISI of Piping ceased operations and have

certified that fuel has been

permanently removed from the

reactor

OL Operating License

CP = Construction Permit

IN99-05 March 8, 1999 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, the appropriate regional office, or the appropriate office of Nuclear Reactor

Regulation (NRR) Project Manager.

orig /s/'d by

Davi 'Fa w serrireFcR

Division of Regulatory Improvement Programs

Office of Nuclear Reactor Regulation

Technical contacts: Beth Korona, Region I Frank Amer, Region I

860-447-3170 610-337-5194 E-mail: bekZnrc.aov E-mail: fiaL&-nrc.gov

Chuck Petrone, NRR Peter S. Lee, NMSS

301-415-1027 301-415-8111 E-mail: cdpenrc.gov E-mail: psll@nrc.gov

Attachments:

1. List of Recently Issued NMSS Information Notices

2. List of Recently Issued NRC Information Notices

• See Previous Concurrence

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IN99-XX

March xx, 1999 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, the appropriate regional office, or the appropriate office of Nuclear Reactor

Regulation (NRR) Project Manager.

David B. Matthews, Director

Division of Reactor Program Management

Office of Nuclear Reactor Regulation

Technical contacts: Beth Korona, Region 1 Frank Amer, Region 1

860-447-3170 610-337-5194 E-mail: bek(&nrc.aov E-mail: fiaL&nrc.aov

Chuck Petrone, NRR Peter S. Lee, NMSS

301-415-1027 301-415-8111 E-mail: cdp@nrc.gov E-mail: psll@nrc.gov

Attachments:

1. List of Recently Issued NMSS Information Notices

2. List of Recently Issued NRC Information Notices

• See Previous Concurrence

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