Communication Plan Key Messages
These key messages represent the collective views of workshop participants and may not represent the final regulatory position of the NRC.
The rulemaking will not alter the waste classification of depleted uranium.
There is a need for interim guidance to be issued by the NRC for use by disposal facility operators and Agreement State regulators during the period before the rulemaking becomes final.
The technical parameters for the site-specific analysis should be specified in the rule language, which would provide uniformity in the technical approaches used by the Agreement States and their disposal facility licensees and allow more alignment across the disposal sites. The NRC will also publish regulatory guidance on implementation to help ensure more uniformity.
DU is currently Class A waste by default since it contains radionuclides not specified listed in Table 1 and Table 2 of 10 CFR 61.55.
It is prudent not to define the term "significant quantity" of depleted uranium in the regulation, as the performance assessment would determine the amount of waste appropriate for disposal.
General agreement among stakeholders not to define the term "unique waste streams" during the initial rulemaking was expressed, as the performance assessment would determine the amount of waste appropriate for disposal.
Large amounts of DU were not analyzed in the final low level waste EIS: the draft of that EIS only considered 17 curies of U-238 or 3 curies of U-235.
Technical details of modeling disposal of large amounts of DU that form the basis of the analysis in SECY-08-0147 were discussed. Limitations of the model include the following: A broad range of climate states were imposed and persisted for the duration of the simulations, climate change was not considered; the clay barrier to radon migration into a home built over or near the disposal area was assumed to stay intact for the duration of the simulations because iw was assumed the facility would be licensed under Part 61 and need to meet the stability requirements.
The period of performance should be specified in rule language with other criteria, such as exposure scenarios, specified in guidance. Development of a numerical value for period of performance needs to balance practical considerations of demonstrating compliance with 10 CFR Subpart C, and the feasibility of modeling longer time periods with high uncertainty.
Due to the potential long period of performance, the requirement to perform and update a disposal facility's performance assessment on a periodic basis should be specified in the rule.
Because large quantities of depleted uranium may be disposed before NRC completes its rulemaking, it would be prudent for the site operator and state regulator to review the existing site-specific performance assessment. The performance assessment should consider the key elements of the analysis of depleted uranium disposal the NRC staff identified in SECY-08-0147.
Consideration should be made to determine if exposure scenarios should be site specific as opposed to setting the regulatory limit for radon dose for an intruder.
Changes to sections of 10 CFR Part 61 (e.g., the performance objectives to specify the inadvertent intruder dose limit) may be necessary and should include more risk and performance based assessments.