The HPF project (Hyperalkaline Plume in Fractured rock) at the Grimsel Test Site comprises an underground long-term field experiment in a shear zone, in-situ radionuclide transport experiments, two laboratory core infiltration experiments, sophisticated reactive transport modeling exercises, studies on radionuclide stability and solubility, innovative on-line measurement techniques and development of equipment for high-pH conditions (K-Na-Ca-OH, pH = 13.4 at 15 °C). Results to date indicate a decrease in the overall transmissivity of the tested shear zone over a duration of 2 years accompanied by channeling of flow as evidenced by repeat dipole tracer testing with Na-fluorescein, 82Br, 131I, 24Na, and 85Sr. The associated evolution in fluid chemistry indicates the in situ formation of Ca-Si-hydrates. Tracer transport modeling of dipole tests are based either on a heterogeneous porous medium approach or on discrete fracture models. Reactive transport modeling is achieving reasonable agreement with a laboratory core infiltration experiment. Integral to the project are supporting sorption / stability studies, colloid measurements, and development of analytical and measurement techniques.

Engineered barrier for HLW repository is composed of the waste form, the canister and the buffer/backfill material. Assessment of the applicability of metal as candidate materials of canister for HLW has been conducted in some countries. Many bronze relics from the XiZhou Dynasty, China, dated from more than 3,000 years ago, have been preserved perfectly. The study on the corrosion of the bronze relics could contribute to the material selection and design of canisters for HLW. The corrosion products of ancient bronzes consist of copper carbonate hydrate, lead carbonate, copper oxides etc. The corrosion mechanism of the substrate was mainly characterized by electrochemical corrosion, whereas the corrosion mechanism of surface layers was characterized by direct chemical corrosion and electrochemical corrosion.

Two different EU projects: the EQUIP project (Evidences from Quaternary Infills from Palaeohydrogeology) running from 1997 to 2000 and the ongoing PADAMOT-project (Palaeohydrogeological Data Analysis and Model Testing) have addressed the possibility of using fracture minerals as recorders of past hydrochemical and hydrogeological environments. The Swedish contribution in these two projects has concentrated on studies of fracture filling calcites from the Äspö/Laxemar area, southeast Sweden.

The analyses applied in the two projects comprise stable isotope ratios of carbon and oxygen and strontium together with trace element contents and textural studies. The results obtained so far (mainly from the EQUIP project) show that several generations of calcite can be identified, chemical zoning is common, and the influence on calcite precipitation of fresh and marine water decreases with depth. It can be concluded that fine scale zoning, possible dissolution/redistribution of calcite, and the disturbances caused by drilling (where loose material which may contain young calcite precipitates were lost), introduce uncertainties in the recognition of different calcite generations. However, despite these problems it is indicated that calcite fracture fillings in Precambrian bedrock environments can add information e.g. concerning changes in groundwater chemistry and redox conditions in the past. The possibilities and problems with palaeohydrogeological interpretations are discussed based on the available data.

Copper and bronze artefacts of Olviya archaeological collection dated the first century B.C. were the objects of this study. Susceptibility to soil corrosion of archaeological artefacts from pure copper and bronze was investigated. Detailed mineralogical and metallographic investigations were performed on specially prepared samples of metallic copper, such as cut and polished sections of a cylindrical body, etc. They reveal a complex picture of metal structure and mineralogical features that can be attributed to both original technological process of manufacturing and to alteration during the burial and weathering history. Corrosion products were researched and the thickness of the corrosion layer formed for the long period of time was determined. It is shown, that the corrosion rate of artefacts produced by casting depends on composition alloys and change of metal structure after the next mechanical-thermal processing. The soil corrosion rate of copper alloys also depends on the redox conditions in the soil of Olviya site.

Nagra - the Swiss National Cooperative for the Disposal of Radioactive Waste - has completed a study to determine the suitability of Opalinus Clay as a host rock for a SF/HLW/ILW repository in a potential siting area (reference repository site) in the Zürcher Weinland in northeastern Switzerland. Geoscientific information has been used to a wide extent for the demonstration of siting and engineering feasibility, and for the demonstration of long-term safety. It is shown that the selected area in the Zürcher Weinland fulfils the fundamental requirements placed on a siting area for a deep geological repository and that, in terms of the Opalinus Clay host rock option, the geological environment is advantageous.

Nagra (the Swiss National Cooperative for the Disposal of Radioactive Waste) has completed a study to determine the suitability of Opalinus Clay as a host rock for a repository for spent fuel (SF), high-level waste from reprocessing (HLW) and long-livedintermediate-level waste (ILW). The proposed siting area is in the Zürcher Weinland region of Northern Switzerland. A repository at this site is shown to provide sufficient safety for a spectrum of assessment cases that is broad enough to cover all reasonable possibilities for the evolution of the system. Furthermore, the system is robust; i.e. remaining uncertainties do not put safety in question.

The biogeochemical processes controlling release of radionuclides from solid low level radioactive waste (LLW) disposed at the Drigg site have been represented in a computational model in order to determine the effects of varying major element chemical parameters and solubility limits of radionuclides. The model is used to provide a source term for radiological safety assessment calculations for the groundwater pathway. Site data has been compared to the results for the initial stages of the model in order to build confidence in the conceptual and mathematical model used to derive the source term for 234U, the key dose contributor, and other radionuclides which are influenced by the biogeochemical processes. Measured aqueous concentrations of radionuclides whose release from LLW is sorption controlled are compared to the model results as a basis to discuss the uncertainty in sorption input parameters used.

The development of a radionuclide transport model for a tunnel of a repository for short-lived low and intermediate level waste is presented in this work. The model is two-dimensional and uses the finite element method to describe a cross-section perpendicular to the tunnel's main axis. It is shown that the use of a realistic geometry of the system, albeit in 2D, results in a transparent model that can handle the equations in a flexible way. The geometry can easily be changed and also extended to a 3D representation without affecting the numerical code. The disadvantage is the computational requirement. It is expected however that radionuclide transport modelling will evolve to 2D or 3D representations that are more realistic and transparent than today's 1D analytical models which involve many simplifications whose impact on the output is difficult to evaluate.

The role of Nirex is to provide the United Kingdom with safe, environmentally sound and publicly acceptable options for the long-term management of all intermediate level and some low level radioactive waste. Nirex has developed its Phased Disposal Concept as one option for the long-term management of radioactive materials. The Phased Disposal Concept represents a stepwise and reversible approach to the disposal of radioactive waste within a deep geological repository that involves the immobilisation of wastes in containers (mainly fabricated from stainless steel) that are surrounded by a cementitious backfill.

The wastes for potential disposal contain materials that may require consideration on the basis of their potential non-radiological hazards. This paper describes a preliminary two-stage methodology for assessing the post-closure impact of the disposal of chemically toxic materials to a conceptual Nirex repository. The study suggests some materials either exceeded current estimates of safe levels, or their impact could not be quantified at this stage but was considered to be of concern. These materials included beryllium, phenol, benzene, and nitrite.

ONDRAF/NIRAS – the Belgian radioactive waste management agency – has published in 2001 the SAFIR 2 report on request of the authorities. The SAFIR 2 report is to be considered as a state-of-the art report and not as a complete safety case. This report gives an overview of the Belgian R&D program related to the geological disposal of HLW and ILW for the period 1990–2000 in the Boom Clay (reference host rock). The three main outcomes of the SAFIR 2 report on which this paper will be more specifically focusing, are the following (including results reported after 2000): long-term safety functions, confirmation of the role of the Boom Clay formation as the main barrier and identification of practical difficulties with respect to technical feasibility (repository design).

One of the greatest challenges in the use of nuclear energy is the high radioactive long-lived waste which is generated during production. It must be dealt with safely and effectively. While technical solutions exist, including deep geological repositories, progress in the disposal of radioactive waste has been influenced, and in many cases delayed, by public perceptions about the safety of the technology. One of the primary reasons for this is the long life of many of radionuclides, actinides and fission products, with half-lives on the order of a hundred thousand to a millions years. Problems of perceptions could be reduced significantly, according to our and many others author's opinion, if there were a way to burn or destroy the most toxic long-lived radioactive wastes. As there are no industrial methods for waste destroying today, in this paper it was suggested a new hybrid, deterministic approach: instead of final waste disposal, long-termed but yet temporal storage only, striving towards final destruction once the appropriate conditions are maintained. This new or modified old approach could affect current HLLLW management and related activities in: changes of processing technology; prolonging the time period of waste storage at temporal depositories; increasing the investment into research regarding the methods and technologies for destructions of these materials, and slowing down the investments into the very expensive final disposal repositories. It is authors' opinion that such deterministic, conceptual approach would contribute the reviving interest in nuclear energy, all over the world and especially in small and developing countries.

The search for greater public acceptance for radioactive waste disposal has meant that repository planning increasingly includes monitoring, institutional control and flexibility with respect to retrieval and reversability. However, the fundamental repository designs are generally unchanged. This paper describes an alternative – the Cavern Extended Storage concept – which aims to incorporate requirements for flexibility and choice for future generations into a deep geological disposal concept that provides a much safer option than extended surface storage.

An alternative strategy is proposed for the disposal of spent nuclear fuel (SNF) and other forms of high-level waste (HLW) whereby the integrity of a mined and engineered repository for the bulk of the waste need be preserved for only a few thousand years. This is achieved by separating the particularly problematic components, notably heat generating radionuclides (HGRs) and very long lived radionuclides (VLLRs) from the waste prior to disposal. Such a solution requires a satisfactory means of disposing of the relatively minor amounts of HGRs and VLLRs removed from the waste. This could be by high-temperature very deep disposal (HTVDD) in boreholes in the continental crust [1,2]. However, the viability of HTVDD, and hence the key to the entire strategy, depends on whether sufficient melting of granite host rock can occur at suitable temperatures and whether the melt can be completely recrystallized. The high-temperature, high-pressure experiments reported here demonstrate that granite can be partially melted and completely recrystallized on a time scale of years, as opposed to millennia as widely believed. Furthermore, both can be achieved at temperatures and on a time scale appropriate to the disposal of packages of heat generating HLW. It is therefore concluded that the proposed strategy, which offers, environmental, safety and economic benefits, could be a viable option for a substantial proportion of HLWs.

A waste management scheme is described, which aims to utilise the ambient pressure of a disposal environment, its radiation shielding and extended time of storage to ensure reliable immobilisation of radioactive waste in a glass composite or polycrystalline matrix form. The conditions required for natural sintering of the waste form in the repository are assessed for viscous flow and grain boundary diffusion mechanisms. In situ sintering of materials in the repository creates geochemically stable materials in equilibrium with the disposal environment ensuring a higher degree of safety compared to existing approaches.