Information Notice 1985-87, Hazards of Inerting Atmospheres

Hazards of Inerting Atmospheres

ML031180195
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, Skagit, Marble Hill
Issue date:	11/18/1985
From:	Jordan E NRC/IE
To:
References
IN-85-087, NUDOCS 8511150098
Download: ML031180195 (6)

SSINS No.: 6835 IN 85-87 UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF INSPECTION AND ENFORCEMENT

WASHINGTON, D.C. 20555 November 18, 1985 IE INFORMATION NOTICE NO. 85-87: HAZARDS OF INERTING ATMOSPHERES

Addressees

license (OL) or a

All nuclear power reactor facilities holding an operating

construction permit (CP) and fuel facilities.

Purpose

events that have

This information notice is provided to alert licensees to to

occurred at nuclear power plants where personnel were exposed

dangerous to life or health (IDLH).

oxygen-deficient atmospheres immediately largely outside the

This notice focuses on personnel safety issues that are

information should be

scope of NRC's nuclear safety requirements. However, the conditions for

helpful to licensees in their efforts to maintain safe working

their employees.

for applicability

It is expected that recipients will review this informationto preclude similar

to their facilities and consider actions, if appropriate, in this notice do

problems at their facilities. However, suggestions contained or written

not constitute NRC requirements; therefore, no specific action

response is required.

Description of Circumstances

In each event, A brief description of the events is provided in Attachment 1. attention. The

workers were physically affected and required prompt medical disturbed

severity of physical effects of inert-gas exposure ranged from resulted from

respiration to loss of consciousness. In one event, two deaths

exposure in an IDLH area.

Discussion:

and carbon

While not toxic themselves, inert gases such as nitrogen, argon, IDLH areas.

dioxide can displace normal air and thereby create oxygen-deficient

air of 1.5 and

Argon and carbon dioxide have specific gravities relative to areas.

1.4, respectively, and thus can present hazards even in open-topped to be inerted, Even after good faith efforts to purge and ventilate areas known gas can

a "de-inerted" area can present personnel hazards. Pockets of inerting is in

oxygen

linger in low-lying areas of the affected spaces. In areas where

can occur rapidly and without warning.

the 8-12% range, unconsciousness

8511150098

IN 85-87 November 18, 1985 Unprotected exposure to an atmosphere containing less than 6% oxygen by volume

(at sea level) causes incapacitation after only a few breaths, convulsive

movements, and death in a few minutes.

Title 29, Code of Federal Regulations, Part 1910.134, provides certain regula- tory requirements for worker protection against respiratory hazards. These

Occupational Safety and Health Administration (OSHA) regulations include (among

other things) requirements for "appropriate surveillance of work area condi- tions," written procedures for the proper use of respirators in dangerous

areas, and special provisions for communication and rescue from hazardous

working areas. However, in three of the four events discussed, unprotected

workers unknowingly entered existing oxygen-deficient IDLH areas. In all but

the Hope Creek event, an effective workplace surveillance program (including

periodic air quality sampling and hazard area controls/posting) could have

identified hazardous areas and possibly prevented worker entry into IDLH areas.

Along with the workplace surveillance program for hazards identification, procedures establishing entry and work requirements can form the basis of an

effective non-radiological hazards control program.

Several information documents are available that could be useful to licensees

trying to improve their worker safety programs. NUREG/CR-3551, "Safety Impli- cations Associated with In-Plant Pressurized Gas Storage and Distribution

Systems in Nuclear Power Plants" (May 1985), provides a detailed, thorough

technical review and offers a broad-perspective-for many aspects of using

compressed gases. The NUREG discusses many elements important to plant safety

that relate directly to a non-radiological hazards control program and person- nel respiratory protection, including (1) physical properties and hazards of

gases, (2) failure modes of gas systems, (3) incidents, and (4) potential

hazards. IE Information Notice 81-26, Part 4, "Personnel Entry Into Inerted

Containment" (August 1981), is another useful reference which discusses a

non-emergency entry into a fully inerted BWR containment at power. The notice

discusses the entry hazards, provides guidance, and lists other pertinent

references. The Institute for Nuclear Power Operations' Good Practice "Safe

Work Procedure for Enclosed Volumes" (OA-101, Rev. October 1983) provides

procedural guidance for safely entering and working in potentially IDLH con-,

fined spaces. Other related correspondence includes: IE Circular 80-03,

"Protection From Toxic Gases" (March 1980), and IE Information Notice 83-62,

"Failure of Redundant Toxic Gas Detectors Positioned at Control Room Ventila- tion Air Intakes" (September 1983). These two issuances focus primarily on

maintaining adequate protection of control rooms against toxic gas threats.

IN 85-87 November 18, 1985 information notice.

No specific action or written response is required by this the Regional

If you have any questions about this matter, please contact

Administrator of the appropriate regional office or this office.

wr A r. I r cto

Division f Emergency Preparedness

and Engineering Response

Office of Inspection and Enforcement

Technical Contacts: James E. Wigginton, IE

(301) 492-4967 Roger L. Pedersen, IE

(301) 492-9425 Attachments:

1. Event Summaries

2. List of Recently Issued IE Information Notices

Attachment 1 IN 85-87 November 18, 1985 Event Summaries

Hope Creek Event Date: September 1985 An inadvertent initiation of the carbon dioxide fire suppression system (FSS)

caused the release of approximately 10 tons of cardox (liquid carbon dioxide

under pressure) into one of the four diesel generator fuel oil storage tank

rooms. The affected room pressurized and carbon dioxide leaked into adjacent

areas where several workers were overcome. Twenty-three people were transported

to nearby hospitals with one individual listed in serious condition upon arrival

(condition later improved to "guarded"). The plant was evacuated, and search

and rescue teams reported some difficulty in accounting for all construction

personnel during the search to ensure all persons had been evacuated.

The cause of the 10 ton continuous discharge (system designed for 2-ton "burst"

release of CO2 ) is still under review, but believed to be caused by a fault in

the FSS control system initiated by moisture electrically shorting FFS control

circuitry. The licensee and OSHA are investigating the incident.

Rancho Seco Event Date: August 1985 With the plant in a cold, shutdown condition, a nitrogen inerting blanket was

placed on a moisture separator reheater. The nitrogen leaked past several shut

valves into the main condenser. A non-licensed operator, while walking down

the condensate system, stopped near the open condenser manway. The operator

passed out because of an apparent local IDLH area created by nitrogen escaping

the condenser. Prompt and effective rescue/first aid was provided by an

accompanying assistant, and the operator was transported to the hospital. No

permanent injury resulted from the incident. As a result of a licensee review

of the lessons learned from the event, the licensee has improved its hazards

controls program for using inerting gases by increasing atmosphere sampling, providing appropriate hazard postings to alert workers, and analyzing the

potential effect on associated systems (e.g., potential leak paths).

D.C. Cook Nuclear Plant Event Date: September 1976 Two workers were killed in a recirculation pit (sump) by asphyxiation from argon

inerting gas used to support welding on stainless steel piping. After the welding

was completed, the argon purge was not secured and gas leakage from the faulty

argon purge-pipe connection filled the pit. When a workman entered the pit to

remove the purge connection, he was overcome by the inerted atmosphere. He and

one of two fellow workers attempting rescue were killed. A licensee safety

review of the incident revealed several work practice deficiencies including:

1. Local ventilation for the pit was available, but not used before entry.

Attachment 1 IN 85-87 November 18, 1985 2. Although the equipment was available, oxygen air sampling was not

performed.

3. "Buddy system" for the first entry into a confined space was not employed.

Other Events

Other instances of problems have occurred during the past few years, many of

which are not reported formally to the NRC. In a typical example, a health

physics (HP) technician was overcome by an oxygen-deficient atmosphere in a

steam generator (SG). The secondary-side of SGs are often nitrogen inerted to

minimize oxygen uptake during non-operational modes. In this case, the wrong

SG was purged of its inerting atmosphere, and an HP technician (when entering

the still-inerted SG) was overcome. Another HP technician on the scene prompt- ly pulled the asphyxiated technician from the IDLH area. No lasting injuries

from the event were noted.

-

Attachment 2 IN 85-87 November 18, 1985 LIST OF RECENTLY ISSUED

IE INFORMATION NOTICES

Information Date of

Notice No. Subject Issue Issued to

85-86 Lightning Strikes At Nuclear 11/5/85 All power reactor

Power Generating Stations facilities holding

an OL or CP

85-85 Systems Interaction Event 10/31/85 All power reactor

Resulting In Reactor System facilities holding

Safety Relief Valve Opening an OL or CP

Following A Fire-Protection

Deluge System Malfunction

85-84 Inadequate Inservice Testing 10/30/85 All power reactor

Of Main Steam Isolation Valves facilities holding

an OL or CP

85-83 Potential Failures Of General 10/30/85 All power reactor

Electric PK-2 Test Blocks facilities holding

an OL or CP

85-82 Diesel Generator Differen- 10/18/85 All power reactor

tial Protection Relay Not facilities holding

Seismically Qualified an OL or CP

85-81 Problems Resulting In 10/17/85 All power reactor

Erroneously High Reading facilities holding

With Panasonic 800 Series an OL or CP and

Thermoluminescent Dosimeters certain material

and fuel cycle

licensees

85-80 Timely Declaration Of An 10/15/85 All power reactor

Emergency Class Implementa- facilities holding

tion Of An Emergency Plan, an OL or CP

And Emergency Notifications

85-17 Possible Sticking Of ASCO 10/1/85 All power reactor

Sup. 1 Solenoid Valves facilities holding

an OL or CP

OL = Operating License

CP = Construction Permit