Transuranic wastes siting

Transuranic Waste. Transuranic wastes (TRU) contain significant amounts (>3,700 Bq/g (100 nCi/g)) of plutonium. These wastes have accumulated from nuclear weapons production at sites such as Rocky Flats, Colorado. Experimental test of TRU disposal is planned for the Waste Isolation Pilot Plant (WIPP) site near Carlsbad, New Mexico. The geologic medium is rock salt, which has the abiUty to flow under pressure around waste containers, thus sealing them from water. Studies center on the stabiUty of stmctures and effects of small amounts of water within the repository. 

In 1989 a deep mined repository, The Waste Isolation Pilot Plant, was opened in a bedded salt formation near Carlsbad, New Mexico. The site has been receiving transuranic wastes since and has now disposed hundreds of tons. 

At present, radioactive wastes are Being held at the DOE facilities including those in Richland, Washington, Savannah River, South Carolina, and at other reactor sites. These transuranic wastes are stored either above ground or in shallow burial pits. Neither of these methods are intended as long-term storage solutions. 

In 1989 a deep mined repository. The Waste Isolation Pilot Plant, was opened in a bedded salt formation near Carlsbad, New Mexico. However, state objections are delaying the experimental emplacement of transuranic wastes from the defense program. In addition, a Nevada site with a tuff formation above the water table has been selected to be intensively studied for disposal of high-level transuranic wastes. In this case also, state objections are delaying the work. It is very uncertain when the first repository will be receiving any transuranic waste, and it probably will not before 2010. ... 

Also resulting from reprocessing are the lower-activity wastes that are contaminated with transuranic elements (TRU waste). These wastes are defined as containing 100 nanocuries of alpha-emitting transuranic isotopes (with half-lives >20 years) per gram of waste. Over 60,000 m are stored retrievably at DOE sites and are destined for disposal at the Waste Isolation Pilot Plant in New Mexico (Aheame 1997). The estimated cost of remediation and restoration programs in the DOE complex during the next few decades is on the order of 200 billion dollars (Crowley 1997). 

Mr. Kazakov discussed problems associated with contamination from the Chernobyl nuclear accident. The first problem is in characterising what portion of the contaminated material in the exclusion zone should be considered radioactive waste and how to deal with it remove it or possibly use materials for construction. Consideration of the extent to which contaminated materials should be removed, as radioactive waste, presents a problem as well. This is related to the second problem in properly characterising the total inventory of the radioactive waste. The waste is characterised at temporary locations of radioactive waste (TLPRW) and radioactive waste burial sites (RWBS). Although there is a great deal of documented information on the locations, volumes and activities, it is unclear whether to categorise the radioactive waste by specific activity, volume or presence of transuranic and fissionable elements in the radioactive waste. 

Much waste from nuclear sites will contain significant amounts of transuranic nuclides. While Am can readily be measured by gamma spectrometry, the plutonium isotopes cannot. However, some of the even-mass plutonium isotopes undergo spontaneous fission (at sub-critical levels ) and emit neutrons at measurable rates as they do so. Drum scanning systems can be combined with neutron-detection systems that can be used to estimate... 

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