Information Notice No. 82-21: Buildup of Enriched Uranium in Effluent Treatment Tanks
SSINS No.: 6835 IN 82-21 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C. 20555 June 30, 1982 Information Notice No. 82-21: BUILDUP OF ENRICHED URANIUM IN EFFLUENT TREATMENT TANKS Addressees: All uranium and plutonium fuel fabrication licensees. Purpose: This notice provides information about the potential for the buildup of enriched uranium in large liquid waste tanks after the waste solutions have been released from criticality control. For nuclear criticality control purposes, licensees must sample or monitor effluent streams containing uranium prior to release of such liquids from favorable geometry hold systems. On two occasions significant quantities of uranium were detected in large, non-favorable geometry effluent treatment systems as a result of post-precipitation or other chemical/mechanical action. This information should be brought to the attention of all personnel having operational and safety responsibilities for waste treatment systems. Description of Circumstances: In one event, uranium was to be removed from waste liquids by precipitation and centrifugation. The centrifugate was pumped through a polishing filter and an inline monitor. If the uranium concentration in the filtrate was low enough, the liquid was directed to a large retention tank with a side discharge. At the request of the NRC inspector, the tank was inspected and found to have a significant quantity of uranium sludge below the discharge line. Corrective actions included relocating the discharge line, improving the recirculation system in the tank, and periodic inspections of the tank for uranium buildup. In a second event, waste solutions containing very low levels of uranium were mixed with a precipitating agent, pumped through a filter press and collected in a large effluent holding tank. The holding tank had a side discharge line about two feet above the bottom of the tank. Sludge containing a significant quantity of uranium was found in the bottom of the tank. Corrective actions included relocation of the discharge line, a study of the precipitation process to assure completion precipitation, prior to filtration, and periodic inspections to detect uranium buildup. . IN 82-21 June 30, 1982 Page 2 of 2 Discussion: These incidents are significant to nuclear criticality safety in that enriched uranium was accumulating beyond "criticality safety release points". If your effluent waste treatment system includes large tanks or other such hold systems, procedures for detection and removal of significant accumulations of enriched uranium from these tanks or other hold or handling systems should be reviewed for adequacy. No written response to this information notice is required. If you need additional information regarding this subject, you should contact the Regional Administrator of the appropriate regional office. L.I. Cobb, Director Division of Fuel Facilities, Materials and Safeguards Technical Contact: D. Sly 301-492-4783 Attachment: List of Recently Issued IE Information Notices
Page Last Reviewed/Updated Tuesday, March 09, 2021
Page Last Reviewed/Updated Tuesday, March 09, 2021