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 G NRC/OE
To:
References
IN-85-031, NUDOCS 8504170236
Download: ML031180339 (3)

SSINS No.: 6835IN 85-31UNITED STATESNUCLEAR REGULATORY COMMISSIONOFFICE OF INSPECTION AND ENFORCEMENTWASHINGTON, D.C. 20555April 19, 1985IE INFORMATION NOTICE NO. 85-31: BUILDUP OF ENRICHED URANIUM IN VENTILATIONDUCTS AND ASSOCIATED EFFLUENT TREATMENTSYSTEMS

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 forapplicability to their facilities and consider actions, if appropriate, to pre-clude a similar problem occurring at their facilities. However, suggestionscontained 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 ofuranium in ventilation ducts and associated effluent treatment systems ofenriched uranium fuel fabrication plants. For nuclear criticality safety pur-poses, licensees establish controls to prevent a buildup of enriched uraniumin unsafe or unfavorable geometry ventilation equipment and other effluenttreatment systems.On two occasions recently, significant quantities of highly enriched uraniumwere found in unfavorable geometry effluent ducts and treatment systems as aresult 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 scrubberwalls above the water line. The deposition appears to have increased as the airstream cooled and when air changed direction in elbows. The accumulation abovethe water line appears to have resulted from splashing and subsequent drying ofscrubber liquid on the scrubber walls. To control this situation the licenseeinitiated a surveillance program to identify accumulations of uranium in theeffluent system and to take appropriate corrective actions when uranium buildup8504170236 IN 85-31April 19, 1985 exceeded predetermined limits. Also, a program was initiated to identify theuranium source and to take remedial actions to prevent the uranium from enteringthe system.In another event, uranium solids were deposited in unfavorable geometry ductsas a result of changes in the speed or direction of air flows. Periodic cleaningof the ducts prevented a significantly large accumulation of uranium. As acontrol measure, the licensee initiated a visual inspection and a radiation detec-tion surveillance program to identify significant accumulation of uranium inunfavorable geometry ventilation and effluent treatment systems.Discussion:These incidents are significant to nuclear criticality safety because enricheduranium accumulated in excess of acceptable quantities in ventilation andeffluent treatment systems of unfavorable geometry. The lack of an adequatelicensee program for detecting, locating, and estimating the quantity of thedepositions 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 RegionalAdministrator of the appropriate NRC regional office or this office.James A. Partlow, DirectorDivisibn of Inspection ProgramsOffice of Inspection and Enforcement

Technical Contact:

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

Attachment 1IN 85-31April 19, 1985LIST OF RECENTLY ISSUEDIE INFORMATION NOTICESInformation Date ofNotice No. Subject Issue Issued to85-30Microbiologically InducedCorrosion Of ContainemntService Water SystemUse Of Unqualified SourcesIn Well Logging Applications4/19/854/12/8585-2985-03Sup. 185-2885-27Separation Of Primary Reactor 4/9/85Coolant Pump Shaft AndImpellerAll power reactorfacilities holdingan OL or CPAll well loggingsource licenseesAll power reactorfacilities holdingan OL or CPAll power reactorfacilities holdingan OL or CPAll power reactorfacilities holdingan OL or CPPartial Loss Of AC Power AndDiesel Generator DegradationNotifications To The NRCOperations Center AndReporting Events In LicenseeEvent Reports4/9/854/3/8585-26Vacuum ReliefBoiling WaterI And Mark IISystem ForReactor MarkContainments4/2/85All BWR facilitieshaving a Mark I orMark II containmentand holding an OL orCP85-2585-2485-2385-22Consideration Of ThermalConditions In The Design AndInstallation Of Supports ForDiesel Generator ExhaustSilencersFailures Of ProtectiveCoatings In Pipes And HeatExchangersInadequate Surveillance AndPostmaintenance And Post-modification System TestingFailure Of Limitorque Motor-Operated Valves ResultingFrom Incorrect InstallationOf Pinon Gear4/2/853/26/853/22/853/21/85All power reactorfacilities holdingan OL or CPAll power reactorfacilities holdingan OL or CPAll power reactorfacilities holdingan OL or CPAll power reactorfacilities holdingan OL or CPOL = Operating LicenseCP = Construction Permit