By Brian Schimmoller, Contributing Editor
In the nuclear power industry, not all waste is created equal. High-level waste, including spent nuclear fuel, garners the most attention because of its long-term radiotoxicity. Low-level waste (LLW), on the other hand, typically flies below the radar. However, the pending closing of a critical disposal facility in South Carolina is focusing attention on the LLW issue.
Low-level waste is just what it sayswaste containing lower levels of radioactivity. LLW is classified in three categories: A, B and C. Class A waste is nominally safe after 100 years, Class B waste after 300 years and Class C waste after 500 years. Nuclear power plants generate significant quantities of LLW each year, through daily maintenance activities, health and safety checkups and during plant outages. Class A waste comprises the bulk of LLW from nuclear power plants, about 85 to 90 percent.
Nuclear plant operators currently have three options for disposing low-level waste:
- The EnergySolutions facility in Barnwell, S.C., which currently accepts Class A, B and C waste from around the country
- The EnergySolutions facility in Clive, Utah, which only accepts certain types of Class A waste and
- The U.S. Ecology facility near Richland, Wash., which accepts Class A, B and C waste from the 11 states in the Rocky Mountain and Northwest Low-Level Waste Compact states.
In 2000, lawmakers in South Carolina initiated a plan to close the state’s doors to nuclear waste from producers outside the Atlantic Compact, which includes South Carolina, Connecticut and New Jersey. The plan goes into effect this summer. The result is that as of July 1, 2008 there will be no Class B and C disposal option for commercial LLW producers in 36 states, meaning about 15,000 cubic feet of material per year will need to find another home.
The obvious solution would be to open another waste disposal facility. In the world of nuclear power, however, the obvious solution is rarely an easy or even acceptable one. While LLW disposal is authorized and regulated according to federal law, actual disposal is a commercial matter, which adds business and economic constraints to the broader array of technical, safety and environmental issues facing waste disposal in general. Moreover, while states have known for some time that LLW disposal capacity could ultimately impact nuclear industry operations around the country, the technical need for such facilities has not overcome opposition and political inertia. Only Texas has a new LLW disposal site under license review and it will only accept wasteat least initiallyfrom Texas and Vermont.
Facing this reality, the nuclear power plants left out in the cold as of July 1 have been taking several steps to ensure LLW disposal does not preclude sustained operation. The first order of business is to reduce the amount of waste generated at nuclear power stations. “We are evaluating a number of specific strategies to reduce the amount of Class B/C waste,” said Graham Johnson, supervising scientist with Duke Energy, which operates two nuclear plants in the Atlantic Compact and one outside the compact. Minimization strategies include operating resin demineralizers with less resin, operating some demineralizers on an as-needed basis (rather than continuously, removing filters from service earlier) and using non-metal filters, which can be processed with steam reforming, leaving very little waste material.
Waste minimization, of course, only reduces waste; it doesn’t eliminate it. With Barnwell out of the equation, out-of-compact plants will have to store LLW on-site for some period of time. How long is uncertain, but one thing is certain: nuclear operators will be getting more familiar with best practices and procedures to ensure proper on-site handling, identification, monitoring and tracking of LLW. Duke Energy already has an on-site outdoor storage facility at its McGuire Station in North Carolina, in which it could safely store LLW for the life of the station, if needed, according to Duke Energy’s Johnson.
The Nuclear Regulatory Commission is currently working to review and update guidance on extended on-site storage of LLW, with completion scheduled by end of the second quarter of 2008, according to an NRC assessment published on its Web site in October (see www.nrc.gov/reading-rm/doc-collections/commission/secys/2007/). The updated guidance is needed because, although NRC guidance already exists, it is obsolete in some cases and may have gaps in security areas.
A third industry strategy to deal with LLW disposal relates to the distinction between Class A, B and C waste streams. Technically, these streams are segregatedphysically and legallyaccording to the ratio of radionuclides in the streams. Those with higher percentages of longer-lived radionuclides are classified as Class B or C and are therefore buried deeper in the LLW disposal facility. Through averaging across waste streams, however, it may be possible to reclassify some amount of Class B/C waste as Class A, enabling disposal in existing facilities. The nuclear industry is investigating whether the NRC’s “Branch Technical Position” could be updated to achieve this reclassification. “It is unclear at this time if this approach will be accepted and how much waste would be a candidate for this approach,” said Johnson. “Clearly, some waste will still be Class B/C, but Duke would welcome an update to the Branch Technical Position.”
Reclassification would not negate the need for LLW disposal facilities, just as closing the nuclear fuel cycle through reprocessing would not negate the need for a high-level waste facility such as Yucca Mountain. Together with waste minimization, however, it would provide some welcome breathing room. So, although not all nuclear waste is created equal, making it more equal could have significant benefits.