Resolution of Generic Safety Issues: NMSS-0016. Adequacy of 0.05 Weight Percent Limit in 10 CFR 40 (Rev. 1) ( NUREG-0933, Main Report with Supplements 1–34 )
Exposure to the “unimportant quantities” of source material, defined in 10 CFR 40.13(a) as less than 0.05 wt% uranium or thorium, could result in annual doses to the public of hundreds of millirem exceeding NRC’s public dose limit of 100 mem/year from all sources. In July 1996, NMSS developed a Draft User Need memorandum requesting development of a regulation to limit the transfer of source material meeting the “unimportant quantity” limit or to revise the definition of source material. Discussions in 1996 and 1997 with RES and OGC indicated that there were several options available to the staff to revise the definition of source material. However, the User Need memorandum was never finalized.
Subsequently, the Division of Fuel Cycle Safety (FCSS)/NMSS received a licensee request to transfer baghouse dust containing less than 0.05 wt% uranium and thorium to an exempt person per 10 CFR 40.51(b)(3) and 40.13(a). Some conservative dose estimates indicated that the transfer could result in doses exceeding the public dose limit. This issue was identified1723 by NMSS to pursue rulemeking to immediately cease transfers under 10 CFR 40.51(b)(3) and 40.51(b)(4) of source material exempted under 10 CFR 40.13(a). By eliminating these provisions, any future transfers would have to meet existing general license conditions or be specifically approved on a case-by-case basis.
This issue was given a medium priority ranking and resolution was pursued.1723 The staff initially pursued a modification to 10 CFR 40.51, “Transfer of source or byproduct material,” to codify the Commission’s direction given in various SRMs. However, in November 2006, NMSS concluded that the existing NRC policy for handling the source material satisfied the intent of the Commission directives, and the issue was closed by the Office of Federal and State Materials and Environmental Management Programs (FSME)/NMSS with no new requirements or guidance for licensees. The staff plans to take further action related to the proposed rule (i.e., publish the final rule or rescind the proposed rule) when the EPA finalizes activities related to its ANPR, and/or the recommendation of the Interagency Jurisdictional Working Group(IJWG) is implemented.1894