[en] Rock salt was heated and irradiated in situ by implanted radioactive wastes during the Project Salt Vault experiment which was carried out at Lyons, Kansas, in the abandoned Carey Salt mine between 1965 and 1967. It was found that irradiation results in coloration of the salt, producing colors ranging from blue-black nearest the radiation source, to pale blue and purple farther from the source. Bleached areas are common in the radiation-colored salt, many representing trails produced by the migration of fluid inclusions towards the heat source. These visible trails are thought to have formed during the cooling down of the salt after the removal of the heaters and radiation sources. The distribution of primary structures in the salt suggests that little migration, if any, occurred during the course of the experiment. It is proposed that radiolysis of the brine within the inclusions may have led to the production of gases which impeded or prevented migration. Evidence of strain was observed in slip planes at 4 in. (10 cm) and between 5.5 and 10 in. (13.5 to 25.4 cm) from the array hole. Deformed bleached areas in the salt between the areas were slip planes are developed suggest that slight plastic deformation or flow may have occurred at 6 in. (15 cm) from the array hole. Differential thermal analysis shows that the maximum amount of stored energy also occurs at 6 in. (15 cm) from the array hole. This region may therefore represent the zone where the combined effect of stress and radiation was greatest

[en] Brief description of the concepts studied by partners; of the Molten Salt Fast Reactor Concept activities; of the activities on MOSART concept; and of activities on FHR concept.

[en] Feasibility study of an underground molten salt thorium reactor is presented. Fuel cycle and safety considerations are given. (TRA)

[en] The underground exploration of a site with a view to its suitability for safe containment and final disposal of radioactive wastes (section 9a subsection 3 Atomic Energy Act) is not yet the beginning of an appropriate installation, and thus the plan approval procedure according to section 9 Atomic Energy Act is not required, this not even in the case of parts of the explored mine, such as shafts, after dimensioning and construction finding use in a final waste repository to be erected in the case of a positive decision on the site on the basis of a plan approval procedure. (Federal Administrative Court, judgment of 9.3.1990, BVerwG 7 G 23.89 (res judicata)). (orig./HP)

[en] Shapes made of salt are used as closures for horizontal or slightly inclined access roads to the hollow spaces. The sections are provided with precise, simple cross-sections for this purpose and are filled with cut shapes made of homogeneous salt to a length of several metres. The sections are then thermally melted at the intended places by heating pipes or laser beams. (PW)

[en] In the last 5 years, there has been a rapid growth in interest in the use of high-temperature (700 to 1000 C degrees) molten and liquid fluoride salts as coolants and for other functions in nuclear systems. This interest is a consequence of new applications for high-temperature heat and the development of new reactor concepts. These salts have melting points between 350 and 500 C degrees; thus, they are of use only in high-temperature systems. Nitrate salts with a peak operating temperature of about 600 C degrees are the highest-temperature commercial liquid coolant available today; thus, the development of higher-temperature salts as coolants opens new nuclear and non-nuclear applications. These salts are being considered for intermediate heat transport loops between all types of high-temperature reactors (helium and salt cooled) and hydrogen production systems, oil refineries, and shale oil processing facilities. Historically, steam cycles with temperature limits of about 550 C degrees have been the only efficient method to convert heat to electricity. This limitation produced few incentives to develop high-temperature reactors for electricity production. However, recent advances in Brayton gas-turbine technology now make it possible to convert higher-temperature heat efficiently into electricity and thus have created the enabling technology for more efficient cost-effective high-temperature reactors. The near-term advanced high-temperature reactor (AHTR) uses a graphite-matrix coated-particle fuel and a liquid salt coolant. There is the longer-term potential of a liquid-salt-cooled fast reactor (LSFR) that uses metal-clad fuel and a liquid salt coolant. The molten salt reactor (MSR), with the fuel dissolved in the molten salt coolant, is receiving attention because of (1) the advancing salt-coolant technology and Brayton cycles that improve the economics, (2) advances in salt chemistry that enable the development of fast-spectrum MSRs with the safety advantages of large negative void coefficients, and (3) the interest in actinide burning where MSRs avoid the need to fabricate fuel of highly active actinides. Last, there is a developing interest in liquid-wall fusion machines with much higher power densities than solid-wall fusion machines. (authors)

[en] According to the present planning level of the designed Gorleben repository, the salt produced by opening up cavities for ultimate disposal will be used as salt fines for backfilling residual cavities after radioactive waste emplacement. The essential function properties of the backfill - compaction and permeability - were studied for salt fines, and the results achieved were discussed. (BBR)

No abstract available

[en] The Thermal/Structural Interactions (TSI) In Situ Tests are a series of large-scale, well instrumented tests that have been constructed at the Waste Isolation Pilot Plant (WIPP) in southeastern New Mexico. As a precursor to the TSI tests, a ventilation drift (Room D) was mined, drilled and instrumented. This room provided the contractor an excellent area to practice controlled construction methods and was proving ground for construction monitoring and documentation methods. All gages in this first room have been monitored since their initial installation, which has provided a small, but representative, data base. These data also were the first to be available from any TSI area for analysis. This paper discusses the construction activities in Room D and the data generated from the construction and drilling. Deformation of the room is compared briefly to numerical calculations that used a rather simple creep model as a reference. The constitutive model for salt, it appears, must be improved before it can predict the underground deformations

[en] Now some conceptual projects of Molten-Salts Based Nuclear Reactors (MSBNR) exists and problem of creating of full-scale demonstration installation of such type is working up seriously enough. Wide researches, confirming reality of solving of the problem of MSBNR building, have already been carried out. At the same time engineer realization of the project needs tests of a whole number of technical and technological solutions, and obtaining of additional data in physics and chemistry of salts and compatibility of materials. Possessing powerful scientific and technical potential and developed experimental base RFNC-VNIITF would have a possibility to bring in adequate contribution to the problem of creating MSBNR