[en] Convergence measurements were taken during the construction of a circular shaft in massive granite. The convergence results were used to back-calculate the in situ horizontal stress orientation and magnitudes. The results from the convergence method were supported by other measurement techniques and numerical modelling. (author). 16 refs., 1 tab., 10 figs

[en] The earthquakes that have occurred around Kiruna in northern Sweden have been studied in detail in order to determine their source characteristics and to understand the pattern of seismic acticity in the region. All earthquakes with magnitude greater than 3.0 (M_L) that occurred during the period between 1967 and 1985 in the region bounded by 66.5 degrees - 69 degrees N and 19 degrees - 25 degrees E are studied. Relocated epicenters of the events exhibit a cluster of events in a direction NE - SW at at the western side of the region close to Kiruna, Though, the focal depths of the events are not very well constrained, the relocation results suggest that the events in this cluster might have occurred at focal depths between 15 and 25 km. At the easstern side of the region, the epicenters are roughly aligned along an elongated area trending NNW - SSE. The focal depths of the events in this area tend to be shallow and are probably in the upper crust at the depths range from 5 to 16 km. The earthquakes studied show nearly constant source radii of about 0.4 - 0.6 km over the seismic moment range 10²⁰ to 10²¹ dyne-cm. Consequently, the events studied are characterized by a steadily incresing stress drop relative to increasing seismic moment. The source mechanisms obtained for the two largest earthquakes suggest that the mechanisms are dominated by the normal faultings on the near-vertical fault planes trending N - S to NE - SW. (With 26 refs.) (authors)

[en] One of the aims in the safety assessment of SFR-1 is to estimate the release to the environment. In order to make these calculations there is a need to describe the inventory in greater detail. The new computerised database of waste in SFR-1 gives a good possibility to achieve this. The aim for project SAFE is to make both conservative and realistic radionuclide transport calculations. To achieve this goal there must be two inventories. The conservative inventory is the inventory used in the design of the repository, which in most parts is identical with the limits in the licence for SFR-1. There is a great interest to have good estimates of the volumes of the different waste types. A thorough prognosis should be made in 1999, but until then the latest one from 1995 could be used in the calculations. The total (actual) inventory of nuclides is calculated from the measurements of the easy-to-measure nuclides since, in principle, all hard-to-measure nuclides are calculated by correlation factors to ⁶⁰Co and ¹³⁷Cs . These factors should be reviewed since there are quite large uncertainties involved. ¹⁴C dominates the individual doses after a few hundred years and the collective dose in the inland-scenario. The amount of the nuclide is uncertain since the correlation factor is very uncertain. The chemical speciation of ¹⁴C is also of interest due to different properties of organic and inorganic carbon. ³⁶Cl is very hard to measure. Although the authorities in their reviews of the safety reports say that there probably are small doses from chlorine, the inventory should be improved. ⁵⁹Ni is a long-lived nuclide that sets a limit to the close-to-the-core metal scrap that can be taken to SFR- 1. There is an ongoing research project to provide a better measuring method for ⁵⁹Ni. This should make it possible to improve the knowledge about ⁵⁹Ni inventory. The assumption that 90 % of the inventory is collected in the ion-exchange resins should be checked. Actinides/⁹⁰Sr are subjects to a special program. The database from this work should be used to calculate a more detailed inventory. Calculations of the amount of different plutonium nuclides in SFR-1 should be done and an estimate of how Actinide nuclides are distributed in the repository should also be performed. Chemical substances in the waste and the waste package and in the construction materials are of great interest since even small amounts can seriously disturb the long term performance of SFR-1. SKB has already started a project to make a better inventory of chemicals in SFR-1. There is also a special program about concrete admixtures going on. These two projects will hopefully improve the knowledge of the chemical substance inventory of SFR-1. The waste package and the matrix are also well defined in terms of which materials are present. The accuracy in the amounts of materials depends on how good the volumes prognosis is. Regarding knowledge of the inventory of the actual waste there is room for improvement in the refuse and scrap metal inventory. A better average composition of different materials should decrease the uncertainties. A literature review of corrosion rates of steel, aluminium and zinc in an alkaline environment should be performed

[en] The IAEA Underground Disposal Programme has so far addressed near-field phenomena only generally in the context of the more important general system considerations. The need for more technical reviews and discussions on subjects of specialised importance in this area is highlighted

[en] The hydrologic evaluation of radionuclide migration from a repository is centered on three areas of uncertainty: the existing hydrologic system at a given site, prediction of events (earthquakes, etc.) altering the hydrologic properties with time, and evaluating the interaction of wastes with the burial environment. The volumes and types of waste are briefly considered. Problems in making the hydrologic evaluation are discussed

[en] Several countries (or member states) are planning to design, build, and operate geologic repositories in the near future for direct final disposal of spent fuel. It is unlikely that any such facilities will be loaded to capacity, backfilled, and sealed before the middle of the next century. The projected ultimate spent-fuel capacities range from ∼2000 to 200000 tonnes of uranium and 20 to 2000 tonnes of plutonium. The observation that spent-fuel repositories become plutonium mines was made during the course of the International Fuel Cycle Evaluation ∼20 yr ago. To appraise fully the non-proliferation issues, the Department of Safeguards has in recent years accelerated its endeavor to develop a safeguards policy as well as technology for implementing appropriate safeguards

[en] In recent years, agencies have worked out directives on an order for inventory-taking, recording mines sites and enterprises, transportation, processing, use collection, storage, and burial of radioactive substances and sources of ionizing radiation. ONe stage in solving this problem concerns management of radioactive wastes: making allowance for them during collection, processing, and burial, which at the present scientific and technical level requires an integrated data base capable of storing and processing large arrays of primary data. The main task in the conceptual design of the data base is to analyze the overall information requirements and to form the initial version of the information model. An analysis of the universe of discourse reflecting the enrichment process with radioactive wastes from the time they are formed in organizations until they are stored in repositories (REPOS), given, has made it possible to specify the following sets data elements, categorized by their essential nature, to give them the labels SUPPLIER, PERSONNEL, INSTRUMENT, WASTES, TRANSPORT, FACILITY, END PRODUCT, REPOSITORY, and PREMISES. Each entity is determined by an ensemble of properties (attributes)

[en] This is the third part of a report of a preliminary study for AECL. It summarizes the topics considered in reports AECL-6188-1 and AECL-6188-2 as requirements for an undergpound repository for disposal of wastes produced by the Canadian Nuclear Fuel Program. (author)

[en] This report provides the final hazard categorization for the remediation of six 300-FF-2 Operable Unit Burial Grounds, the 618-1, 618-2, 618-3, 618-7, 618-8, and 618-13 sites.

[en] This paper outlines test protocols to determine the chemical stability and radionuclide release behavior of waste forms produced from aluminum based spent nuclear fuels