[en] Vitrification of Savannah River Site (SRS) high level radioactive waste is scheduled to begin in late 1995. The vitrification operation will take place at the SRS Defense waste Processing Facility (DWPF). The US Department of Energy has instituted specifications which provide technical criteria which must be met by the DWPF to ensure that the waste glass will be suitable for permanent disposal in a federal geologic repository. Included in these criteria is a specification requiring DWPF to determine whether its high level, radioactive waste glass should also be classified as characteristically hazardous waste. A study was performed, using the anticipated range of glass compositions which will be produced over the lifetime of the DWPF, which definitively proved that DWPF waste glass should not be classified as characteristic hazardous waste

[en] The Nuclear Waste Policy Act of 1982 mandated that all high-level waste (HLW) be sent to a federal geologic repository for permanent disposal. DOE published the Environmental Assessment in 1982 which identified borosilicate glass as the chosen HLW form.¹ In 1985 the Department of Energy instituted a Waste Acceptance Process to assure that DWPF glass waste forms would be acceptable to such a repository. This assurance was important since production of waste forms will precede repository construction and licensing. As part of this Waste Acceptance Process, the DOE Office of Civilian Radioactive Waste Management (RW) formed the Waste Acceptance Committee (WAC). The WAC included representatives from the candidate repository sites, the waste producing sites and DOE. The WAC was responsible for developing the Waste Acceptance Preliminary Specifications (WAPS) which defined the requirements the waste forms must meet to be compatible with the candidate repository geologies

[en] Nonradioactive hazardous metal components of the DWPF waste streams are subject to regulation under RCRA. Vitrified material also falls under this regulation, potentially impacting disposal of glass generated during the DWPF Startup Test Program. RCRA-approved leach tests were performed on simulated DWPF waste glass to determine whether the glass should be classified as hazardous. The results of the tests verified that DWPF waste glass is not a hazardous waste

[en] The bases for control of electric melters with high level radioactive waste feed are complex. Preliminary limits are described for vitreous immobilization of high level radioactive waste at the US Department of Energy's Savannah River Site (SRS) in the Defense Waste Processing Facility (DWPF). Limits will be finalized based on extensive operation of the actual DWPF equipment, using simulated radioactive feed. Radioactive waste-glass production requires chemical control to assure adequate durability (aqueous leach resistance), physical control limits and glass composition control to assure continuous melter operation, and to sustain glass production. Glass composition, melter feed batching and melter temperature control are used to produce waste glass with adequate durability in a manner which avoids the formation of phases which are disruptive to melting or reduce melter life. Alternative control methods of product and process controls have been considered. It has been determined that product control and glass melting temperature controls the quality of the glass product. Further, it has been determined that process control is necessary to maintain the efficient operation of the facility. The essential requirements are maintenance of melter operation, control of the chemical composition of the mixtures fed to waste glass melters, and a minimum time at temperature to fuse the feed into a glass product. Variables considered for control in waste glass production include: temperature, glass residence time in melter, glass composition, glass durability limits, glass solubility limits, waste loading limits, glass redox control, combustible gas accumulation and sooting, glass cooling rate control, glass devitrification control, and glass cracking control. 56 refs., 1 tab

[en] Measurements of neutrons and hard x rays are made with a pair of plastic scintillators during injection of deuterium pellets into deuterium TFTR plasmas. Three cases are investigated. During ohmic heating in plasmas with few runaway electrons, the neutron emission does not increase when a pellet is injected, indicating that strong acceleration of the pellet ions does not occur. In ohmic plasmas with low but detectable levels of runaway electrons, an x-ray burst is observed on a detector near the pellet injector as the pellet ablates, while a detector displaced 126⁰ toroidally from the injector does not measure a synchronous burst. Reduced pellet penetration correlates with the presence of x-ray emission, suggesting that the origin of the burst is bremsstrahlung from runaway electrons that strike the solid pellet. In deuterium beam-heated discharges, an increase in the d-d neutron emission is observed when the pellet ablates. In this case, the increase is due to fusion reactions between beam ions and the high density neutral and plasma cloud produced by ablation of the pellet; this localized density perturbation equilibrates in about 700 μsec. Analysis of the data indicates that the density propagates without forming a sharp shock front with a rapid initial propagation velocity (greater than or equal to 2 x 10⁷ cm/sec) that subsequently decreases to around 3 x 10⁶ cm/sec. Modelling suggests that the electron heat flux into the pellet cloud is much less than the classical Spitzer value

[en] The Department of Energy (DOE) Office of Environmental Restoration and Waste Management (EM) has developed Waste Acceptance Product Specifications (EM-WAPS). The EM-WAPS will be the basis for defining product acceptance criteria compatible with the requirements of the Civilian Radioactive Waste Management System (CRWMS). The relationship between the EM-WAPS and the CRWMS Systems Requirements document (WA-SRD) will be discussed. The impact of the EM-WAPS on the Savannah River Sit (SRS) Defense Waste Processing Facility's (DWPF) Waste Acceptance Program, Waste Qualification Run planning, and startup schedule will also be reported. 14 refs., 2 tabs

[en] The US Department of Energy (DOE) weapons complex has numerous radioactive waste streams which cannot be easily treated with joule-heated vitrification systems. However, it appears these streams could be treated With certain robust, high-temperature, melter technologies. These technologies are based on the use of plasma torch, graphite arc, and induction heating sources. The Savannah River Technology Center (SRTC), with financial support from the Department of Energy, Office of Technology Development (OTD) and in conjunction with the sites within the DOE weapons complex, has been investigating high-temperature vitrification technologies for several years. This program has been a cooperative effort between a number of nearby Universities, specific sites within the DOE complex, commercial equipment suppliers and the All-Russian Research Institute of Chemical Technology. These robust vitrification systems appear to have advantages for the waste streams containing inorganic materials in combination with significant quantities of metals, organics, salts, or high temperature materials. Several high-temperature technologies were selected and will be evaluated and employed to develop supporting technology. A general overview of the SRTC ''High-Temperature Program'' will be provided

[en] The in-vivo behaviour of sulphur colloid has been investigated using colloids labelled with ³⁵S as well as sup(99m)Tc. The rates of clearance of ³⁵S and sup(99m)Tc from the blood, the rates of accumulation in liver and bone and the distribution of the two radioisotopes in various organs are all markedly different. The results demonstrate that although technetium is rapidly removed from the blood stream and primarily accumulated in the liver the colloid particles themselves are broken down in vivo with the release of sulphur. (orig.)

[en] Nonradioactive hazardous metal components of the DWPF waste streams are subject to regulation under RCRA. Vitrified material also falls under this regulation, potentially impacting disposal of glass generated during the DWPF Startup Test Program. RCRA-approved leach tests were performed on simulated DWPF waste glass to determine whether the glass should be classified as hazardous. The results of the tests verified that DWPF waste glass is not a hazardous waste

[en] The characteristics of sulphur colloids have been investigated using colloids labelled with ³⁵S as well as with sup(99m)Tc. The results support a model in which technetium is incorporated in the body of the particle rather than on its surface. Elemental sulphur on the surface of the particle is susceptible to attack both by sulphide ions and by protein and other materials containing -SH groups. The ready conversion of sulphur to soluble polysulphides means that sulphur colloid particles undergo conspicuous changes in diameter, both while standing in a closed vial, and on injection into body fluids. This behaviour casts doubts on the value of routine particle-size measurement as aquality control procedure. (orig.)