Information Notice 1985-31, Buildup of Enriched Uranium in Ventilation Ducts and Associated Effluent Treatment Systems

Buildup of Enriched Uranium in Ventilation Ducts and Associated Effluent Treatment Systems

ML031180339
Person / Time
Issue date:	04/19/1985
From:	Partlow J NRC/OE
To:
References
IN-85-031, NUDOCS 8504170236
Download: ML031180339 (3)

SSINS No.: 6835 IN 85-31 UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF INSPECTION AND ENFORCEMENT

WASHINGTON, D.C. 20555 April 19, 1985 IE INFORMATION NOTICE NO. 85-31: BUILDUP OF ENRICHED URANIUM IN VENTILATION

DUCTS AND ASSOCIATED EFFLUENT TREATMENT

SYSTEMS

Addressees

All uranium fuel fabrication licensees.

Purpose

This information notice is provided to alert recipients of a potentially signi- ficant problem pertaining to criticality safety at enriched uranium fuel fabri- cation plants. It is expected that recipients will review the information for

applicability to their facilities and consider actions, if appropriate, to pre- clude a similar problem occurring at their facilities. However, suggestions

contained in this information notice do not constitute NRC requirements; there- fore, no specific action or written response is required.

Description of Circumstances

This notice provides information regarding a potential for the buildup of

uranium in ventilation ducts and associated effluent treatment systems of

enriched uranium fuel fabrication plants. For nuclear criticality safety pur- poses, licensees establish controls to prevent a buildup of enriched uranium

in unsafe or unfavorable geometry ventilation equipment and other effluent

treatment systems.

On two occasions recently, significant quantities of highly enriched uranium

were found in unfavorable geometry effluent ducts and treatment systems as a

result of settling or deposition of uranium-bearing solids.

In one event, uranium-bearing solids or vapors were picked up in the ventila- tion system and deposited on the inside of the ventilation ducts and scrubber

walls above the water line. The deposition appears to have increased as the air

stream cooled and when air changed direction in elbows. The accumulation above

the water line appears to have resulted from splashing and subsequent drying of

scrubber liquid on the scrubber walls. To control this situation the licensee

initiated a surveillance program to identify accumulations of uranium in the

effluent system and to take appropriate corrective actions when uranium buildup

8504170236

IN 85-31 April 19, 1985 exceeded predetermined limits. Also, a program was initiated to identify the

uranium source and to take remedial actions to prevent the uranium from entering

the system.

In another event, uranium solids were deposited in unfavorable geometry ducts

as a result of changes in the speed or direction of air flows. Periodic cleaning

of the ducts prevented a significantly large accumulation of uranium. As a

control measure, the licensee initiated a visual inspection and a radiation detec- tion surveillance program to identify significant accumulation of uranium in

unfavorable geometry ventilation and effluent treatment systems.

Discussion:

These incidents are significant to nuclear criticality safety because enriched

uranium accumulated in excess of acceptable quantities in ventilation and

effluent treatment systems of unfavorable geometry. The lack of an adequate

licensee program for detecting, locating, and estimating the quantity of the

depositions was the major contributing factor.

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 NRC regional office or this office.

James A. Partlow, Director

Divisibn of Inspection Programs

Office of Inspection and Enforcement

Technical Contact:

Douglas Sly

(301) 492-4783 Attachment: List of Recently Issued IE Information Notices

Attachment 1 IN 85-31 April 19, 1985 LIST OF RECENTLY ISSUED

IE INFORMATION NOTICES

Information Date of

Notice No. Subject Issue Issued to

85-30 Microbiologically Induced 4/19/85 All power reactor

Corrosion Of Containemnt facilities holding

Service Water System an OL or CP

85-29 Use Of Unqualified Sources 4/12/85 All well logging

In Well Logging Applications source licensees

85-03 Separation Of Primary Reactor 4/9/85 All power reactor

Sup. 1 Coolant Pump Shaft And facilities holding

Impeller an OL or CP

85-28 Partial Loss Of AC Power And 4/9/85 All power reactor

Diesel Generator Degradation facilities holding

an OL or CP

85-27 Notifications To The NRC 4/3/85 All power reactor

Operations Center And facilities holding

Reporting Events In Licensee an OL or CP

Event Reports

85-26 Vacuum Relief System For 4/2/85 All BWR facilities

Boiling Water Reactor Mark having a Mark I or

I And Mark II Containments Mark II containment

and holding an OL or

CP

85-25 Consideration Of Thermal 4/2/85 All power reactor

Conditions In The Design And facilities holding

Installation Of Supports For an OL or CP

Diesel Generator Exhaust

Silencers

85-24 Failures Of Protective 3/26/85 All power reactor

Coatings In Pipes And Heat facilities holding

Exchangers an OL or CP

85-23 Inadequate Surveillance And 3/22/85 All power reactor

Postmaintenance And Post- facilities holding

modification System Testing an OL or CP

85-22 Failure Of Limitorque Motor- 3/21/85 All power reactor

Operated Valves Resulting facilities holding

From Incorrect Installation an OL or CP

Of Pinon Gear

OL = Operating License

CP = Construction Permit