Background on LLRW Blending

Since the closure of the LLRW disposal facility at Barnwell, South Carolina on June 30, 2008, the issue of blending of LLRW has received increased attention from stakeholders, industry, and Agreement States, especially blending that results in a change in the classification of the waste, as defined by the radionuclide concentrations in 10 CFR Part 61.55. Blending is not prohibited nor is it explicitly addressed in current NRC regulations. Existing NRC staff guidance discourages blending in some circumstance, but also recognizes that some blending, including blending that lowers the classification of a waste, may be appropriate in others. However, the closure of the Barnwell facility to LLRW generators in 36 States means that they have no disposal option for their Class B or C LLRW and must therefore store it, typically at their licensed facility. Any waste with Class B or C concentrations that could be blended down to Class A could potentially be disposed of at an existing Class A facility, and not have to be stored by licensees at their facilities. While some blending of LLRW resulting in reduced waste classification has occurred in the past, the scale of blending being considered since the closure of Barnwell has expanded.

NRC's guidance on blending of LLRW is contained in the 1995 Concentration Averaging Branch Technical Position (BTP). Although this document addresses many issues associated with concentration averaging of LLRW (i.e. the mathematical averaging of radioactivity concentrations in solid, non-mixable, materials, such as reactor components), it also addresses blending of homogeneous wastes. The BTP discourages blending by recommending a limit on the range of concentrations of batches that can be mixed. At the same time, these recommendations do not apply when there are operational efficiencies or worker dose reductions that can be achieved.

On October 8, 2009, the Chairman directed the staff to prepare a Commission vote paper on blending, noting that there were policy issues associated with blending that the Commission needed to consider. The staff completed the paper, SECY-10-0043, "Blending of Low-Level Radioactive Waste," on April 7, 2010. In developing the paper, the staff held public meetings with the three primary industry stakeholders to hear their views on blending. The staff also held a facilitated roundtable discussion with all stakeholders on January 14, 2010. Roundtable members included LLRW generators, waste processers, disposal facility operators, advocacy groups, the States, and Department of Energy. The views of these stakeholders were addressed in the staff's Commission paper. The paper identified and analyzed regulatory, safety, and policy issues and provided four different options on a blending position for Commission consideration. The staff-recommended option was for NRC to adopt a risk-informed, performance-based blending position, consistent with the Agency's overall policy for regulating its licensees. Other options included maintaining the status quo (i.e., relying on existing blending guidance), prohibiting large-scale blending (i.e., blending of multiple generators' waste at an offsite processing facility), and adopting a regulation similar to Texas's which allows blending, but requires that waste be classified based on its highest concentration before blending, thus eliminating one of its primary advantages, the lowering of the waste class.