[en] The nuclear utilities in Sweden are responsible for managing and disposing of spent nuclear fuel and radioactive waste from the nuclear power reactors in a safe manner. The most important measures are to plan, build and operate the facilities and systems needed, and to conduct related R and D. This report presents a calculation of the costs for implementing all of these measures. The following facilities and systems are in operation: Transportation system for radioactive waste products. Central interim storage facility for spent nuclear fuel, CLAB. Final repository for radioactive operational waste, SFR I. Plans also exist for: Encapsulation plant for spent nuclear fuel. Deep repository for spent fuel and other long-lived waste. Final repository for decommissioning waste. The cost calculations also include costs for research, development and demonstration, as well as for decommissioning and dismantling the reactor plants etc. At the end of 1995, certain amendments were made in the Financing Act which influence the calculations presented in this report. The most important amendment is that the reactor owners, besides paying a fee or charge on nuclear energy production, must also give guarantees as security for remaining costs. In this way the fee can be based on a probable cost for waste management. This cost includes uncertainties and variations that are normal for this type of project. Cost increases as a consequence of major changes, disruptions etc. can instead be covered via the given guarantees. The total future costs, in January 1998 prices, for the Swedish waste management system from 1999 onward has been calculated to be SEK 45.8 billion. The total costs apply for the waste obtained from 25 years of operation of all Swedish reactors. They will fall due over a total period of approximately 50 years up to the middle of the 2l st century, but the greater part will fall due during the next 20 years. It is estimated that SEK 12.1 billion in current money terms has been spent through 1998

[en] This report considers the potential physical and chemical perturbations caused by the excavation, operation and backfilling and sealing of a KBS-3 type repository for spent fuel in Sweden. Parts of the underground excavations are likely to remain open to the atmosphere for up to several decades. Time-dependent changes to the chemical environment and the properties of the geological formation will be occurring as well as the initial disturbance of construction and subsequent changes after backfilling. In addition, this report also discusses issues that arise from the co-disposal of spent fuel and intermediate level waste. The processes which are likely to act during each stage of a repository from construction through to backfilling and sealing have been reviewed and the degree to which these processes are understood and represented within the performance assessment is discussed. The areas of particular interest are: The coupling of thermal, hydrogeological and mechanical processes with particular reference to the development of the near-field; Understanding the transient process of re-saturation with particular reference to the buffer material surrounding the waste canisters, including chemical changes to the material; The impact of accidental events during the construction and operational phases of work and their possible consequence on the long term performance of the repository; Chemical issues relating to the co-disposal of spent fuel and intermediate level wastes within a single facility. When consideration of transient processes and coupling is discussed, it is apparent that numerical tools and a complete understanding to provide quantitative information is lacking. The importance of the engineered barrier system within the performance assessment for spent fuel disposal is recognised and the emphasis is placed on the understanding of the coupled processes in the evolution in the near-field of the geosphere

[en] This project was performed within the fifth and final phase of sub-project RAK-2.1 of the Nordic Co-operative Reactor Safety Program, NKS. RAK-2.1 has also included studies of reflooding of degraded core, recriticality and late phase melt progression. Earlier source term calculations for Swedish nuclear power plants are based on the integral code MAAP. A need was recognised to compare these calculations with calculations done with mechanistic codes. In the present work SCDAP/RELAP5 and CONTAIN were used. Only limited results could be obtained within the frame of RAK-2.1, since many problems were encountered using the SCDAP/RELAP5 code. The main obstacle was the extremely long execution times of the MOD3.1 version, but also some dubious fission product calculations. However, some interesting results were obtained for the studied sequence, a total loss of AC power. The report describes the modelling approach for SCDAP/RELAP5 and CONTAIN, and discusses results for the transient including the event of a surge line creep rupture. The study will probably be completed later, providing that an improved SCDAP/RELAP5 code version becomes available

[en] The input data in the near field compartment model concerning the connection between the hole in the canister wall and the surrounding bentonite has been studied. The calculations show that Z-AREA and A-ZERO must be given equal values in order to achieve consistent dimensions of the hole and the equivalent plug. The usage of an equivalent plug in the connection between the small hole and a large bentonite compartment is valid only if the hole is small compared to the area of the surrounding bentonite. It was shown that a hole with an area larger than about 0.001 m² overestimates the resistance between the hole and bentonite. An alternative is to make the model without the plug. However, in many cases with large hole the plug resistance is small compared to the total resistance and there is no need to take away the plug. In the case of an initially large hole it is better to exclude the plug from the model

[en] SFR-1 is a facility for disposal of low-level radioactive operational waste from the nuclear power plants in Sweden. Low-level radioactive waste from industry, medicine, and research is also disposed in SFR-1. The facility is situated in bedrock beneath the Baltic Sea, 1 km off the coast near the Forsmark nuclear power plant. SFR-1 was built between the years 1983 and 1988. An assessment of the long-term performance of the facility was included in the vast documentation that was a part of the application for an operational license. The assessment was presented in the form of a final safety report. In the operational licence for SFR-1 it is stated that renewed safety assessments should be carried out at least each ten years. In order to meet this demand SKB has launched a special project, SAFE (Safety Assessment of Final Disposal of Operational Radioactive Waste). The aim of the project is to update the safety analysis and to prepare a safety report that will be presented to the Swedish authorities not later than year 2000. Project SAFE is divided into three phases. The first phase is a prestudy, and the results of the prestudy are given in this report. The aim of the prestudy is to identify issues where additional studies would improve the basis for the updated safety analysis as well as to suggest how these studies should be carried out. The work has been divided into six different topics, namely the inventory, the near field, the far field, the biosphere, radionuclide transport calculations and scenarios. For each topic the former safety reports and regulatory reviews are scrutinised and needs for additional work is identified. The evaluations are given in appendices covering the respective topics. The main report is a summary of the appendices with a more stringent description of the repository system and the processes that are of interest and therefore should be addressed in an updated safety assessment. However, it should be pointed out that one of the improvements proposed as a part of the prestudy concerns the development of a systematic description of the SFR process system. Such an exercise may reveal additional improvements or new issues of importance for the safety assessment

[en] The Finnish bedrock has been investigated since 1987 for final disposal of spent nuclear fuel. Saline groundwaters have been observed at Olkiluoto and Haestholmen, two of the presently studied four sites. The new sampling equipment, PAVE, keeps deep groundwater samples in the in situ-pressure. The pressure vessels of the PAVE sampling system are divided into two parts by a movable, o-ring sealed piston. As the pressure compartment of the pressure vessel is filled with argon gas, the piston moves up. Then the sample compartment of the pressure vessels is vacuumed. If a microbe sample is included in the sampling programme, the equipment is first sterilized and then vacuumed. So far the PAVE sampler has been used in studies for dissolved gases and microbes. The salinity of groundwaters at Olkiluoto and Haestholmen increases with increasing depth, suggesting longer residence times and enhanced water-rock interaction. The signs of the ancient Litorina seawater are most prominent at about 100-400 m. The deep, saline Ca-Na-Cl groundwaters at Olkiluoto have low Eh values, high amounts of S^2- and dissolved gases (mainly CH₄ and H₂) suggesting anaerobic microbiological activity. The deep, saline groundwaters at Haestholmen have much higher amounts of Fe and somewhat lower pH values compared to those at Olkiluoto. The high U contents of the rapakivi bedrock of Haestholmen are reflected in the high He contents of dissolved gases. At both sites the deep (below 500 m), saline groundwaters are mixtures of preglacial meteoric waters and some old, hydrothermal saline fluid. The relative enrichment of Br and Ca compared to Cl and Na in the most saline groundwaters corresponds to the brines from the Canadian and Fennoscandian shields

[en] This paper presents the development and functionality of a suite of applications which are being developed to support the geological investigations in the Tono URL. GEOMASS will include 3D geological modelling, 3D fluid flow and solute transport and 3D visualisation capabilities. The 3D geological modelling in GEOMASS will be undertaken using a commercially available 3D geological modelling system, EarthVision. EarthVision provides 3D mapping, interpolation, analysis and well planning software. It is being used in the GEOMASS system to provide the geological framework (structure of the tectonic faults and stratigraphic and lithological contacts) to the 3D flow code. It is also being used to gather the geological data into a standard format for use throughout the investigation programme. The 3D flow solver to be used in GEOMASS is called Frac-Affinity. Frac-Affinity models the 3D geometry of the flow system as a hybrid medium, in which the rock contains both permeable, intact rock and fractures. Frac-Affinity also performs interpolation of heterogeneous rock mass property data using a fractal based approach and the generation of stochastic fracture networks. The code solves for transient flow over a user defined sub-region of the geological framework supplied by EarthVision. The results from Frac-Affinity are passed back to EarthVision so that the flow simulation can be visualized alongside the geological structure. This work-flow allows rapid assessment of the role of geological features in controlling flow. This paper will present the concepts and approach of GEOMASS and illustrate the practical application of GEOMASS using data from Tono

[en] This overview focuses on some major issues for risk analysis appearing in our recent study surveying radioactive sources on the Kola Peninsula, along with adjacent parts of the Arctic seas. The main issues of the parts are as follows: An introduction to the presence of radioactive sources and environmental contamination in the Barents Euro-Arctic Region and the current status as regards various significant studies. Radioactive contamination in man and the environment on the Kola Peninsula, as well as radioactive transfer during the last three decades from external sources to the Kola-Barents region. The main conclusion from the findings is that the contamination is generally relatively low and that neither the activity levels in samples of soil, vegetation, and the important food-chains, nor the content in man indicate any changes since 1986 that could not be explained by the combined effect of the cumulative deposition from the nuclear weapons testing and the accident in Chernobyl. The radioactive sources of main concern in the region belong to the following categories: nuclear power submarine and cruiser naval bases; civil nuclear power ice-breaker fleet; building and repairing shipyards; nuclear power plants; radioactive waste and spent nuclear fuel storage facilities; sunken reactors/ships; liquid radioactive waste dumping; solid radioactive waste dumping; nuclear weapon bases; nuclear weapon tests; civil nuclear explosions; nuclear accidents; mining radioactive ore deposits and plants; new projects and others. Several case studies concerning releases in the Kola-Barents region are reviewed, and followed by consequence analyses for the categories of primary interest covering: a) airborne releases from the Kola NPP, and from submarines or spent nuclear fuel; b) releases from objects in the marine environment including submarines, dumped reactors, and various other radioactive objects and waste; c) releases from liquid and solid wastes stored on land or during transport. The danger of uncontrolled chain reactions constitutes a potentially severe risk associated with both nuclear submarines and spent nuclear fuel. The problems involved in maintaining adequate and sufficient storage capacity have escalated recently. At present most storage facilities are filled to the limit. The principal research needs have been identified and classified in two groups. The first concerns objects or situations of known or probable risk, for which the radiological consequences may be relatively high. The need of research given high priority reflects the known or potential importance of certain chains of events for radioactive releases and associated radiological consequences. The assessments and ranking of priority summarised in this report often focus directly on radiological consequences. However, severe accidents leading to radioactive release are likely to influence social and economic conditions in areas subjected to substantial radioactive contamination. Such associated socio-economic effects have not been touched upon at least not explicitly. Yet, these issues are undoubtedly highly relevant, and constitute elements that besides the radiological issues proper would be particularly suited for further analyses. Some facets of this complex interactions are also discussed

[en] Biokinetic and dosimetric models for a number of clinically used radiopharmaceuticals, for which information on the radiation dosimetry is scarce, have been produced. On patients undergoing investigations with ¹¹¹In-DTPA-D-Phe¹-octreotide (for diagnosis of neuroendocrine tumours) and ^99mTc-MIBI (for myocardial perfusion imaging), whole body gamma camera scanning was performed several times after administration of the radiopharmaceutical. Total body and organ activity content was determined using the geometric mean of the number of counts in two 180 deg opposed planar images. A thorough investigation of sources influencing the accuracy of the quantification of activity was carried out, showing an overall uncertainty varying from 10% to 30% for organs with a significant uptake and 5% for the whole body. The activity in blood and urine was also measured. ¹¹¹In-DTPA-D-Phe¹-octreotide was predominantly excreted via the kidney-bladder system and a typical investigation with 1200 MBq resulted in an effective dose of 8.4 mSv (0.076 mSv/MBq). ^99mTc-MIBI was to a great extent excreted via the gastrointestinal tract and an investigation with 1200 MBq resulted in an effective dose of 13 mSv (0.011 mSv/MBq). Accelerator mass spectrometry (AMS) was used to investigate the possibility to measure ultra-low activity concentrations of ¹⁴CO₂, in exhaled air from patients undergoing ¹⁴C-breath tests, with special application to ¹⁴C-triolein (for study of fat malabsorption). AMS was proven to be a useful technique for long-term retention studies of ¹⁴C, and was used together with liquid scintillation counting in an investigation of the biokinetics of ¹⁴C-urea in adult and paediatric patients (for diagnosis of Helicobacter pylori infection in the upper gastrointestinal tract). The effective dose for ¹⁴C-urea was 0.019 mSv/MBq for adults and from 0.041 to 0.019 mSv/MBq for seven- to fourteen -year-old children, resulting in an effective dose of approximately 0.002 mSv per investigation for adults as well as for children down to the age of seven

[en] Several experiments and theoretical models of intermediate energy heavy ion collision physics are presented in this thesis. Statistical and dynamical aspects of nuclear collisions are widely discussed these days, particularly in connection with the multifragmentation phenomenon and the possible link to a liquid-gas phase transition in the spinodal region of nuclear matter phase diagram. Experimental techniques which allow us to measure various parameters of hot and dense (equilibrated) regions (emission sources) formed in a heavy ion collision are well established nowadays. In recent CHIC (Celsius Heavy Ion Collaboration) experiments the properties of such sources were measured using slowly ramping mode of the CELSIUS storage ring. In this thesis the entropy and chaos production in nuclear collisions is discussed in connection with the t/d/p ratios. Subthreshold pion production explores collective effects in heavy ion collisions and brings additional information about the equation of state of nuclear matter. Continuous pion production excitation functions were measured in the beam energy region from far below the nucleon-nucleon threshold up to the delta dominant region. Mass and angular dependencies of pion production are discussed. A version of the molecular dynamics model which includes pion production in direct nucleon-nucleon collisions was developed and experimental data were analysed in the scope of this model. Properties of the emission sources formed in heavy ion collisions at energies below 50A MeV were studied in the experiments of fragmentation type performed by CHIC. Temperatures of these sources were extracted from fragment energy spectra and from 'isotopic effect'. A version of the quantum molecular dynamics model, where the Pauli potential is introduced into the Hamiltonian, was combined with the statistical multifragmentation model and used to explore dynamical and statistical properties of the reaction development. The artificial neural networks were utilized for the analysis of data from the CHICSi detector which is described in details in this thesis