[en] The nuclear power program in Sweden consists of 12 reactors. Up to the year 2010, these units will give rise to some 7800 tonne of spent nuclear fuel. Present planning foresees that the spent fuel will be stored at the existing interim storage facility for ∼40 yr before final disposal in a geological repository. Such a repository is planned to be located in bedrock and to be in operation from 2020. A siting application should be submitted to the pertinent authorities around 2000. The application for a siting permit must be based on a system adapted to the site and on a comprehensive analysis of the long-term safety of the system. To perform such adaptation and safety analysis, the site must be carefully characterized. During the 1990s, therefore, it is planned to select and characterize at least two candidate sites. The characterization would take ∼5 yr at least and should therefore start about 1993. Before starting any detailed site investigations, the methods to be used must be developed, carefully tested, and verified. A great part of the ongoing research in Sweden is devoted to these tasks. This paper gives a few examples of projects that are of great importance in this respect: the international Stripa project, the Finnsjon fracture zone study, and the Swedish Hard Rock Laboratory

[en] In discussions about spent nuclear fuels, plutonium is often mentioned as a specially difficult substance to handle. It is important that the debate is founded on correct data and facts. Such information has been compiled in this report, which also deals with some examples of plutonium toxicity that have been used in the Swedish debate recently. The purpose of the report is to provide the interested layman with easily accessible data on properties, use of, availability and health hazards of plutonium. 9 refs., 3 figs

[en] In discussions about spent nuclear fuels, plutonium is often mentioned as a specially difficult substance to handle. It is important that the debate is founded on correct data and facts. Such information has been compiled in this report, which also deals with some examples of plutonium toxicity that have been used in the Swedish debate recently. The purpose of the report is to provide the interested layman with easily accessible data on properties, use of, availability and health hazards of plutonium. The report is un updated version of the report SKB-R--97-10

[en] It is desirable to obtain an experimental check of the reliability of the methods currently used to determine reactivity changes in a reactor and, with a view to meeting this requirement to some extent, a preliminary comparison has been made between calculated and measured cross-section changes in rods of natural uranium irradiated in NRX. The measurements were made at Harwell in the GLEEP reactor and a description has been given by, inter alia, Ward and Craig. The theory of the calculations, which is briefly described in this report, has been indicated by Littler. The investigation showed that the methods for calculating burn up used at present provides a good illustration of the long-term variations in isotope contents. A satisfactory agreement is obtained with experimental results when calculating apparent cross-section changes in uranium rods due to irradiation if the fission cross- section for ²³⁹Pu is set to 780 b. This is 34 b higher than the figure quoted in BNL - 325 (1958). However, in order to get a good idea as to whether the calculated long-term variations in reactivity really correspond to reality, it is necessary to make further investigations. For this reason the results quoted in this report should be regarded as preliminary

[en] Within the Swedish KBS-project a great effort has been devoted to the development of canisters for the encapsulation of high level vitrified waste or spent unreprocessed fuel. The canisters will upon final disposal in deep geological formations provide an extra engineered barrier against the dispersal of radioactive nuclides in the groundwater. Comprehensive studies have been made on two types of pure metal canisters, i.e., lead--titanium for the high level vitrified waste and pure copper for spent fuel. The final disposal is made in hard crystalline rock where the waste canisters are embedded in a buffer material - a clay with good long term stability. For the lead--titanium canister a mixture of quartz sand and bentonite is proposed whereas for the copper canister highly compressed bentonite is preferred. Careful evaluations predicted a lifetime of at least thousands of years for the lead--titanium canisters and probably tens of thousands of years in the actual environment. For the copper canister it is realistic to expect a lifetime of hundreds of thousands of years. Comprehensive studies have also been made of a ceramic canister of alumina for spent fuel. Through hot isostatic pressing it is possible to make a completely tight and joint-free alumina container. Alumina has a very high chemical and mechanical resistance over very long periods of time. Preliminary studies have also been made of a glass ceramic material of the beta-spodumenetype. 9 figures

[en] In a comparison between pressure tube and pressure vessel type reactors for pressurized D₂O coolant and natural uranium, one can say that reactors of these two types having the same net electrical output, overall thermal efficiency, reflected core volume and fuel lattice have roughly the same capital cost. In these circumstances, the fuel burn-up obtainable has a significant influence on the relative economics. Comparisons of burn-up values made on this basis are presented in this report and the influence on the results of certain design assumptions are discussed. One of the comparisons included is based on the dimensions and ratings proposed for CANDU. Moderator temperature coefficients are compared and differences in kinetic behaviour which generally result in different design philosophies for the two types are mentioned, A comparison of different methods of obtaining flux flattening is presented. The influence of slight enrichment and other coolants, (boiling D₂O and gases) on the comparison between pressure tube and pressure vessel designs is discussed and illustrated with comparative designs for 400 MW electrical output. This paper was presented at the EAES Enlarged Symposium on Heterogeneous Heavy Water Power Reactors, Mallorca, October 10 - 14, 1960

[en] The once-through fuel cycle in the LWR has come into focus over the last 10 to 15 years. It has been adopted as the preferred option in several countries. Interim storage periods in the range of 10 to 50 years have been proposed in various countries. This provides flexibility with respect to the final choice of disposal method and allows the residual heat and radiation from the fuel to decay, thus facilitating final disposal. Extensive studies of spent fuel leaching are in progress and are expected to make more accurate quantitative prediction models available in the early or mid-1990s. Several materials for encapsulation are being studied in several countries. Selection of material will depend on the particular conditions in the geological environment selected for the repository. The once-through fuel cycle is economically attractive in Sweden and several other countries under current conditions. (author). 6 refs, 5 figs, 2 tabs

[en] This is a condensed version of the proposals of the Swedish Nuclear Fuel Safety Project (KBS). It consists of two parts; safe final storage of vitrified waste, and safe final storage of spent nuclear fuel. In this report are proposals which are detailed and comprehensive to permit a safety evaluation. These proposals specify concretely in which form the waste or spent fuel is to be stored, how the storage facility is to be designed and how transportation is to be effected. For unreprocessed spent nuclear fuel, proposals indicate how and where an absolutely safe final storage can be effected. Various stages in the handling of the fuel on its way to final storage are fully described. Briefly summarized, the report stipulates that the high-level radioactive waste will be in the form of borosilicate glass cylinders containing 9% fission products. The cylinders will be surrounded by 10 cm of lead, which is further encased in a titanium canister. The canisters are placed in deposition holes drilled in the tunnel floor. The holes are backfilled with a sand-clay mixture. The fuel assemblies are dismantled and the rods are encased in copper containers with 20 cm thick walls. The cylindrical containers are deposited into holes drilled in the floor of a tunnel system. The spaces between the rock and copper canisters are filled with compacted bentonite clay

[en] Direct disposal without reprocessing is the main strategy for management of spent nuclear fuel in Sweden. Under the present circumstances this is the most economic route. Before final disposal the fuel will be stored for about 40 years in CLAB, a sepcially built underground facility which was put in operation in July, 1985. This will give flexibility in the choice of final disposal method. Wastes from reactor operation will be disposed of in SFR, another underground facility in hard rock with planned operation starting in 1988. The total cost for waste management in Sweden is estimated to 47 billion SEK (5.5 billion US$) or about 0.02 SEK/kWh (2.4 mills/kWh) including all types of waste and also the decommissioning of all twelve nuclear power facilities. (author)

[en] This conference was held in 1993 in Prague, Czech Republic to provide a forum for exchange of state-of-the-art information on radioactive waste management. Volume 2 contains 109 papers divided into the following sections: recent developments in environmental remediation technologies; decommissioning of nuclear power reactors; environmental restoration site characterization and monitoring; decontamination and decommissioning of other nuclear facilities; prediction of contaminant migration and related doses; treatment of wastes from decontamination and decommissioning operations; management of complex environmental cleanup projects; experiences in actual cleanup actions; decontamination and decommissioning demolition technologies; remediation of obsolete sites from uranium mining and milling; ecological impacts from radioactive environmental contamination; national environmental management regulations--issues and assessments; significant issues and strategies in environmental management; acceptance criteria for very low-level radioactive wastes; processes for public involvement in environmental activities and decisions; recent experiences in public participation activities; established and emerging environmental management organizations; and economic considerations in environmental management. Individual papers have been processed separately for inclusion in the appropriate data bases