Low-level waste, disposal

Fig. 4. Integrated vault technology for low level waste disposal where A represents waste containers that are placed in concrete overpacks and sealed with grout B, closed modules covered with a multiple-layer earthen cover, to direct water away from modules, and short rooted vegetation for erosion control and C, overpacks placed in reinforced concrete modules which are closed with a reinforced concrete roof Courtesy of Chem-Nuclear Systems, Inc.

Methods to control infiltration of water into low level waste disposal faciUties are being studied. Three techniques that may be employed separately, in sequence, or in conjunction are use of a resistive layer, eg, clay use of a conductive layer, involving wick action and bioengineering, using a special plant cover. 

Large volumes of mill tailings may not be sent to a low-level waste disposal facility. 

Another credible assumption is that permanent access to the site could occur at the end of the 100 y period of institutional control. This assumption has been used in establishing waste acceptance criteria at all DOE low-level waste disposal sites (DOE, 1988c 1999c), including the Hanford site, based on an acceptable dose from chronic exposure of an inadvertent intruder of 1 mSv y Therefore, the waste acceptance criteria for the Hanford site already take into account an acceptable dose to an inadvertent intruder from permanent site occupancy, so the waste is acceptable for near-surface disposal as low-hazard waste according to this scenario without the need for further analysis. 

Rilley R.W.D., McHugh J.O., Champ D.R., Cooper E.E., Young J.L. (1984) Subsurface cobalt-60 migration from a low-level waste disposal site. Environ. Sci. Technol. Vol. 18, p. 148-157. 

Releases from the nuclear fuel cycle may occur during reactor operations, nuclear fuel reprocessing, UFg conversion, uranium enrichment, uranium fuel fabrication, high-level waste solidification, high-level and low-level waste disposals. The enrichment process, with a significant aimual release through liquid discharges to the sea, is considered as the key contributor. So far, the total release of Tc to the... 

There has been a rapid growth in use of isotopes in medical research, medical therapy, smoke detectors, static eliminators, sealed sources for a variety of purposes including weld checks, geophysical examinations, etc. Most of these wastes will be buried in low level waste disposal facilities. 

While the question of low level waste disposal has found practical answers in several countries, there is to-day no concrete experience available on deep geological disposal of high level or long lived waste. To compensate for die lack of eiqierience, a specially careful safety approach is deemed necessary, in particular at the stages of site selection and deep repository design studies, a major present-day issue. Deep geological repositories will be addressed in this presentation from the point of view of repository system integration and overall safety. 

He noted that the cost of large volume very low level waste disposal in Centre de I Aube is too expensive and that other solutions are being sought. Limited experience exists in France of metal recycle internal to nuclear industry - it has been handled on a "case by case basis" - there is no national scheme for handling such wastes. He discussed press reactions to radioactive sources found... 

In a study of insect-plant relationships at Oak Ridge National Laboratory, Crossley (1963) utilized a field nuclear waste site containing Cs. Chrysomela knabi beetle larvae were collected on leaves from willow trees (Salix nigra) growing on White Oak Lake bed. This lake was formerly a low-level waste disposal site at the laboratory, and the sediments contained various radionuclides, including Cs. Consequently, the leaves of the willow tree contained Cs... 

McGahan, D. j. 1987. Survey of microbiological effects in low-level waste disposal to land. Atomic Energy Research Establishment Report AERE R 12477, Harwell, UK. 

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