Information Notice 1985-06, Contamination of Breathing Air Systems

Contamination of Breathing Air Systems

ML031180698
Person / Time
Site:	Beaver Valley, Millstone, Hatch, 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, 05000000, 05000262, Zimmer, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant, Skagit, Marble Hill, Crane
Issue date:	01/23/1985
From:	Jordan E NRC/IE
To:
References
IN-85-006, NUDOCS 8501230236
Download: ML031180698 (5)

SSINS No.: 6835 IN 85-06

UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF INSPECTION AND ENFORCEMENT

WASHINGTON, D.C.

20555

January 23, 1985

IE INFORMATION NOTICE NO. 85-06: CONTAMINATION OF BREATHING AIR SYSTEMS

Addressees

All nuclear power reactor facilities holding an operating license (OL) or

construction permit (CP).

Purpose

This information notice is provided to alert licensees to two events resulting

in the radioactive contamination of compressed air systems used to supply

breathing air to respirator users at nuclear power plants.

It supplements

information previously provided in Information Notice 79-08 which discussed

similar events.

Licensee corrective actions and lessons learned from the two

relatively recent events and other previously documented occurrences are

discussed. It is expected that recipients will review this information for

applicability to their facilities and consider actions, if appropriate, to

preclude similar problems occurring at their facilities. However, suggestions

contained in this notice do not constitute NRC requirements; therefore, no

specific action or written response is required.

Description of Circumstances

Event 1 During September 1984, portions of the Browns Ferry service air system (SAS)

were contaminated with gaseous radioactivity directly from the station's

augmented offgas system (AOG).

The SAS and AOG were cross-connected via a

rubber hose (with a single check-valve). Air from the SAS was being supplied

to remove moisture from the AOG hydrogen analyzer sample line downstream of the

AOG hydrogen/oxygen recombiner.

Evidently this was a routine maintenance

activity. When the SAS on-line and backup air compressors failed and the air

receivers bled down, freshly produced radioactive offgas entered the service

air through the temporary hose connection. This condition existed for approxi- mately 2 1/2 hours; fortunately, no one used the system as a breathing air

supply during this period.

Plant personnel became aware of the problem after the air compressors were once

again operable. Apparently the offgas in a portion of the SAS line near an

area radiation monitor tARM) was compressed and caused the ARM to alarm

(lOmR/hr alarm set point). Only short-lived noble gases and their daughter

8501230236

IN 85-06 January 23, 1985 products were found in the SAS, and no explosive or flammability problems were

reported.

Along with tightened administrative controls, double check-valve

backflow protection is now required when cross-connecting to the SAS.

Event 2 On July 19, 1983, workmen while cutting up spent fuel racks inside a

tent-containment structure at H.B. Robinson were wearing air-line respirators

fed by the plant's instrument air system (IAS). While attempting to connect the

air manifold assembly to a different IAS supply point before putting on their

respirators, two workers were exposed to dust and rust particles from the

initial air surge. When "frisked," the two workers found themselves contami- nated.

Air sampled from the contaminated air line contained about 6.6E-8

2 pCi/cc (corresponding to an MPC fraction of 14.1).

On the basis of these air

samples and the whole-body counting, the workers involved were assigned radio- active intakes of less than 40 MPC-hrs.

The licensee investigated the incident, sampled other portions of the IAS, and

found no other radioactive contamination problems.

The source of the IAS

contamination could not be definitely determined.

Therefore, as part of the

corrective actions taken, the licensee now samples and analyzes for radioactiv- ity at each air supply connection point before the breathing air is used.

Discussion

The NRC staff is aware of other instances where installed service air systems

used to provide personnel breathing air have been contaminated (see Attachment

1 for references).

On the basis of a review of licensees' corrective actions

and discussions with the licensees' operating staff, the lessons learned from

the referenced events are summarized as follows:

1.

Radiological air sampling before use can help prevent inadvertent intakes

of radioactivity when infrequently-used portions of service/instrument air

systems are used as breathing air sources.

This precautionary radiologi- cal sampling of the air system would complement the periodic radiological

sampling and industrial hygiene sampling necessary to ensure continued

Grade D quality (or better) for supplied air as required by 30 CFR 11 and

10 CFR 20.

2. Operating procedures can provide for effective administrative controls and

establish physical separation criteria to prevent cross-contamination when

air systems are temporarily connected to contaminated systems.

To mini- mize the potential for cross-contamination, some licensees use intermedi- r

ate air motors (driven by service air) to directly supply air to a

contaminated system.

This approach is applicable only when the air supply

loads are low enough to be supplied by the air motors.

3. There is that potential for "an unreviewed safety question" situation when

system operations are changed from what is described in the Safety Analy- sis Report, such as cross-connecting contaminated and noncontaminated

systems.

IE Circular No. 80-18, "10 CFR 50.59 Safety Evaluations for

IN 85-06 January 23, 1985 Changes to Radioactive Waste Treatment Systems" discusses general princi- ples and philosophy of the 10 CFR 50.59 safety evaluation guidance and

provides insight as to when safety evaluations are necessary to ensure

that changes to SAR-described systems are properly evaluated.

4. For permanent, as-designed interconnections between installed compressed

air systems and contaminated systems, periodic function checks;-and mainte- nance of the system separation protection features (e.g., check valves and

air operated ball valves) can help ensure continued integrity of the

separation.

5. Procedures governing the startup, operation, and maintenance of "add-on"

air handling equipment (e.g., pressure regulating/filtration manifold) can

ensure proper air purging (blowing down) to remove contaminants such as

dead-leg water and rust before the air is used for breathing.

While a separate breathing air supply and distribution system is the ideal

source of worker-supplied air and this can be justified for plants at the

design stage, the physical and economic constraints of installing a separate

breathing air system in an existing facility might be overly burdensome.

Properly modified plant SASs and IASs, with attendant maintenance and sampling

surveillance programs, can be adequate, reliable sources of breathing air for

plant workers.

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

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

Administrator of the appropriate regional office or this office.

gL/ ~dan, Director

Divisi n f Emergency Preparedness

and tfgineering Response

Office of Inspection and Enforcement

Technical Contacts: J. E. Wigginton, IE

(301) 492-4967

R. L. Pedersen, IE

(301) 492-9425 Attachments:

1. References

2. List of Recently Issued IE Information Notices

Attachment 1

IN 85-06

January 23, 1985 References

1. U.S. Nuclear Regulatory Commisssion, Office of Inspection and Enforcement, Information Notice No. 79-08, "Interconnection of Contaminated Systems

with Service Air Systems used as a Source of Breathing Air," March 28,

1979.

2. Institute for Nuclear Power Operations, Significant Event Report (SER)

26-82, "Radioactive Contamination of Service Air System," issued 1982.

Attachment 2

IN 85-06

January 23, 1985

LIST OF RECENTLY ISSUED

IE INFORMATION NOTICES

Information

Date of

Notice No.

Subject

Issue

Issued to

85-05

Pipe Whip Restraints

Inadequate Management Of

Security Response Drills

1/23/85

1/17/85

85-04

85-03 Separation Of Primary Reactor 1/15/85

Coolant Pump Shaft And

Impeller

85-02

85-01

Improper Installation And

Testing Of Differential

Pressure Transmitters

Continuous Supervision Of

Irradiators

Reconcentration Of Radio- nuclides Involving Discharges

Into Sanitary Sewage Systems

Permitted Under 10 CFR 20.303

Potential For Loss Of Water

From The Refueling Cavity

Cracking Of Flywheel On

Cummins Fire Pump Diesel

Engines

1/15/85

1/10/85

12/21/84

12/17/84

12/17/84

All power reactor

facilities holding

an OL or CP

All power reactor

facilities holding

an OL or CP, & fuel

fabrication & pro- cessing facilities

All pressurized water

power reactor

facilities holding an

OL or CP

All power reactor

facilities holding

an OL or CP

All material licensees

possessing irradiators

that are not self- shielded and contain

more than 10,000

curies of radioactive

material

All NRC materials

licensees other than

licensees that use

sealed sources only

All power reactor

facilities holding

an OL or CP

All power reactor

facilities holding

an OL or CP

84-94

84-93

84-92 OL = Operating License

CP = Construction Permit