KYT-2010 Public Nuclear Waste Management Program in Finland. Framework programme

Transcription

1 KYT-2010 Public Nuclear Waste Management Program in Finland Framework programme For research period

2 1 Preface Table of Contents 1 Introduction 1.1 Nuclear waste management in Finland 1.2 Former public nuclear waste management research programme 1.3 Research programme: preliminary preparations 2 Research programme: general features 2.1 Premises and targets 2.2 Research programme organization 2.3 Project search and financing decision 3 Detailed objectives of the KYT2010 research programme 3.1 Nuclear waste management: strategic clarifications 3.2 Final disposal of nuclear wastes: safety assessment 3.3 Studies of social impacts 4 Research programme: reportage and communication 5 Cooperation Annex Segmentation of safety research contents

3 2 Preface The Nuclear Energy Law of Finland stipulates that all nuclear waste [1] produced in Finland must be handled and disposed of in Finland. In accordance with the Law, the producers of the waste are solely responsible for the safe handling, management and disposal of their wastes. This responsibility includes the needed R&D and all costs arising. For regulating the safe management of nuclear wastes, there are two main authorities in Finland; the Ministry of Trade and Industry (The Ministry) having the overall leadership and control in nuclear energy matters in Finland and the Radiation and Nuclear Safety Authority STUK being the national safety technical regulatory body. Accordingly, there are three main R&D programs on nuclear waste management in Finland with the following main features: The program of Posiva Ltd; the company is owned by the Finnish nuclear power companies Teollisuuden Voima Oy and Fortum Oyj and the program is mainly aimed at planning and implementing the disposal of spent nuclear fuel in Finland; The program of STUK; the regulatory R&D program aimed at supporting the regulatory decision making of STUK while regulating Posiva and the power companies; The KYT 2010-program orchestrated by the Ministry; As stipulated in the Nuclear Energy Law, KYT 2010-program is aimed at supporting the creation and maintenance of the overall competence and the basic abilities needed for regulatory purposes, and at assessing alternative solutions for long term management of spent fuel. In accordance with the Law, projects approved to the KYT 2010-program can not be (i) related to any one facility project or (ii) satisfying regulatory STUK needs which are related to any one particular facility project. Therefore, KYT 2010 projects must be of generic nature applicable for multiple users. This document describes the KYT-2010 program. Ministry of Trade and Industry, Department of Energy [1] In accordance with the Law, spent nuclear fuel is considered as nuclear waste.

4 3 1 Introduction 1.1 Nuclear waste management in Finland The Nuclear Energy Act and decree define the clear contexts for the implementation of Finland s nuclear waste management. According to the amendment to the law in 1994, all nuclear wastes produced in Finland must be permanently disposed in Finland. In accordance with the legislation, the producers of nuclear wastes are explicitly responsible for the planning, implementation and costs of waste management, including the research and development work. The basic aims and planning schedule of nuclear waste management were determined by a policy decision of the Government in After this, the decision and schedule concerned have been further specified by the Ministry of Trade and Industry, for instance, 1991, 1995 and The schedules have been observed well. The management of spent nuclear fuel is a pivotal project whose progress still requires many years of deliberate planning and work. According to the plans, the spent fuel is subject to final disposal in canisters at an underground final disposal facility constructed at Eurajoki s Oikoluoto. The nuclear power companies individually are responsible for operating of all measures connected with the management of lowand intermediate-level and decommissioning wastes. Posiva Oy, a company jointly owned by TVO and Fortum, is in charge of the research and development of the final disposal of spent nuclear fuel and construction and operation of the disposal facility. For low- and intermediate-level nuclear waste, there are underground repositories already in operation at Loviisa and Olkiluoto. The power plant sites also have interim storages for spent nuclear fuel. It is the purpose that the spent nuclear fuel from these water basin stores shall in due course be transferred to Posiva Oy s final disposal facility planned at Olkiluoto. According to the plans and decisions, this should be ready for use in about The schedule set for licensees under a waste management obligation requires an application for a construction license to carry out the final disposal facility plans connected with Posiva Oy s project, to be completed in According to the current schedule, the plans should be ready by 2012.

5 4 1.2 Former public nuclear waste management research programme Publicly financed nuclear waste management research was launched in Finland already at the outset of the 1970s, on the initiative of the Atomic Energy Advisory Board. The public administration s coordinated nuclear waste management programmes have been implemented in our country as initiated by The Ministry since The publicly funded JYT nuclear waste research programme was carried out between the years (Vuori 1990, 1991, 1993). The public administration s JYT2 nuclear waste research programme was implemented in (Vuori 1997). The public administration s JYT2001 nuclear waste research programme was carried out in (Vuori 2000, Rasilainen 2002). The KYT National Nuclear Waste Management Research Programme was implemented between the years (Rasilainen 2006). The KYT programme carried out technical/natural science-related research projects in two areas of study: 1) strategic clarifications and 2) long-term safety of the final disposal of spent fuel. The strategic clarifications concentrated on the new nuclear fuel cycles, in particular the partitioning and transmutation (P&T) connected with the same. The long-term safety of final disposal for spent nuclear fuel clearly encompassed much more. Its research areas were: 1) safety analysis methodology, 2) release of radionuclides from the final disposal facility, 3) bedrock and groundwater, 4) migration of radionuclides in the bedrock and 5) biosphere studies. During the years , research in the KYT programme was funded collectively by organizations in the field, in such wise that each organization made its own financing decisions independently. A change in the Nuclear Energy Act, which came into effect at the outset of 2004, changed the financing arrangements so that research funding is granted by the State Nuclear Waste Management Fund (the Fund). 1.3 Research programme: preliminary preparations The four-year KYT programme was initiated by resolution of the Finnish Ministry of Trade and Industry (The Ministry), 4 Feb 2002 (Dnro 54/070/2001, 1/460/2002). In 2005, the Ministry as well as both the Nuclear Energy Advisory Committee (YEN) and the steering group of the KYT research programme deliberated on the Fund-financed research organization following the end of the KYT programme period.

6 5 On , the Ministry made a decision (Dnro 3/811/2005) with respect to the initiation of a new Public Nuclear Waste Management Program in Finland (KYT2010), to take place over a five-year period ( ). Representatives were invited to join the research programme steering group from the Radiation and Nuclear Safety Authority of Finland (STUK), Posiva Oy, Teollisuuden Voima Oy, Fortum Power and Heat Oy and the Finnish Funding Agency for Technology and Innovation (Tekes). In addition, the steering group has a representative from the Ministry. The Ministry published a letter of invitation concerning the KYT2010 programme research project proposals on (Dnro 4/811/2005). In the letter of invitation, not only the research programme itself was outlined but also the schedule for submitting the project proposals and the criteria for selecting the projects. A coordinator was appointed for the research programme at the beginning of 2006 after the public competition was carried out during the autumn of Research programme: general features 2.1 Premises and targets The points of departure for the KYT2010 research programme derive from the amended Nuclear Energy Act of The Nuclear Energy Act stipulates that financial resources are to be gathered annually for nuclear waste management research from those under obligation for nuclear waste management, according to the rationales presented in the legislation. On its part, the Fund annually distributes the resources gathered each year for research projects on the basis of the proposal by the Ministry. On the annual level, the Fund can direct slightly over one million euros into nuclear waste management research projects, which is significantly smaller than the yearly research and development funding for nuclear waste management respective to Posiva and the power companies. Although the role of KYT2010 is to supplement the research sphere in the field, it is nevertheless of considerable importance to many research facilities. The KYT programme primarily realizes projects by which the national foundation of know-how is consolidated in the nuclear waste field. Funding is not granted for research which is linked directly with projects belonging to licensees under nuclear waste management obligation or their representative interests, nor for

7 6 research directly required under the supervision of nuclear waste management. Projects that can be implemented in the research programme are also those that are co-financed by the Fund and other Finnish or foreign financiers. For instance, national part-financing is in most instances required for the purpose of participating in European Union projects. The same terms of financing and requirements are applied to co-financed projects as to those that are financed by the Fund. Other financiers besides the Fund can bring their projects which suit the content and goals of the programme into the sphere of the programme. The research programme steering group makes decisions separately on a project-by-project basis with regard to the practical procedures for these types of projects. The research programme also endeavours to function as a discussion and communication forum among officials, nuclear waste organizations and research facilities. In this way, the prerequisites are created for the effective utilization of limited research resources. According to the Nuclear Energy Act, the pivotal target of the KYT2010 research programme is the acquisition and upkeep of high-standard Finnish know-how, so that the authorities easily have, as required, the sort of nuclear engineering expertise and other facilities available on a sufficient scale. On an annual basis, the total research project to be financed should support this aim in an appropriate manner. It is evident that the main part of KYT2010 research shall be focused on technical/natural scientific safety studies in the research programme. In the inspection of nuclear waste managementrelated alternatives, aspects may nevertheless emerge which give reason to also direct the Fund research resources to social research regarded as important. The KYT2010 research programme endeavours on its part to correct blind spots perceived in national know-how. These may be research themes which have up to this point remained largely unnoticed or expansion projects related to research methods, e.g., modelling supplementing experimental research. There is good reason to develop new know-how at research facilities in which the continuity of research activity connected to the theme is likely. Expertise must not be left to the disposal of one researcher alone: rather, it is a good idea to organize a functional research group or network round the same.

8 7 Another real issue emphasizing the educational perspective is the impending retirement of experienced Finnish researchers over the next few years, which will increase the need to recruit new specialists. The national research programme is a natural forum for supporting training, because it involves actors in nuclear waste management as well as the most pivotal universities and research facilities in our country. Attaching dissertations to research projects is one way to network young specialists into the field. 2.2 Research programme organization Practical work in the KYT2010 research programme is based on mutual cooperation and labour distribution with respect to the steering group, support group, coordinator and research projects. The content of the research programme is annually contoured by the selection and focusing recommendations made by the steering group to The Ministry, as suggested by the research institutions. The framework programme is a framework for project proposals and it facilitates the work of the proposal makers and analyzers. The role of the steering group is to act as the organ coordinating the programme administration and general trends in research. The steering group steers the planning of the research programme and monitors the quality of the research results. The steering group ensures that annual proposals on the granting of the Fund financing for research projects are prepared for the Ministry within the framework of the programme. It also assesses the need to participate in public international research projects. The Ministry has asked for proposals for candidates from the organizations in the nuclear waste field and from Tekes to become members and deputy members of the steering group (letter of , Dnro 3/811/2005). The Ministry appoints a steering group on the basis of these proposals. The chairman of the steering group is from the Radiation and Nuclear Safety Authority (STUK). The coordinator of the research programme acts as secretary. During the five-year research period, the need for external assessment of the research programme may arise. The steering group discusses the assessment requirement and makes a recommendation to the Ministry. The support group functions as reinforcement for the steering group as a 10-person technical specialist body. The steering group selects the members of the support group. Among other things, the support group assesses, in a detailed manner, the project proposals

9 8 and formulates, on the basis of its assessment, an annual financing proposal draft for the steering group. The support group monitors the appropriate internal work distribution, observing the progress of the research projects by, for instance, keeping an eye on the invoicing rights of the projects. The support group may, as required, give support to the project supervisors in the research programme in, e.g., problematic internal research circumstances and in the reportage on the research results. The support group also operates as an information distribution forum in matters connected with both the KYT2010 programme and its external nuclear waste research. The task of the coordinator is to compile the research plans for the steering group and, in accordance with the instructions of the support group, monitor the implementation of plans and report on the progress of projects to the steering and support groups. In addition, s/he prepares the steering group s meetings under the direction of the chairperson and acts as the steering group secretary. In obtaining coordination services, the job description is specified in greater detail. The coordination services of the research programme will be set up for competitive bid by the Ministry in the autumn of Project search and financing decision The projects selected annually for the research programme are selected via publicly realized competitive bid by the Ministry. In assessing the project proposals, the main emphasis is on proposals which the steering group regards as corresponding best to the current requirements of nuclear waste management. The most upto-date requirements can be separately specified in the letter of invitation respective to the search concerned. Pivotal assessment criteria which should be taken into consideration in preparing the project proposal are: the beneficial character of the results, particularly in assessing the safety of nuclear waste management, but also other utility, e.g., support for the strategic choices of nuclear waste management; the development of new expertise; the logicality and clarity of the project proposal; the realism of the project proposal: in other words, the applicant s possibilities to implement his project; the amount of domestic and international cooperation.

10 9 The support group evaluates the content of the project proposals and composes a draft of the financing recommendation for the steering group. The steering group handles the draft and provides, on the basis of the same, a funding recommendation for the Ministry. The Ministry makes an official financing proposal on the annual research programme, Fig. 1. Project proposals (October) Assesment (Nov.-Dec.) Financing proposal (January) Financing decision (March) Projects to finance KYT2010 Steering group (recommendation) Advisory Committee on Nuclear Energy (statement) Ministry of Trade and Industry State Nuclear Waste Management Fund (financing decision) (financing proposal) Support group (assesment) Radiation and Nuclear Safety Authority (STUK) (statement) Other possible financiers Fig. 1. The annual schedule for decision-making concerning KYT2010 programme research projects. The annual schedule for decision-making derives from the fact that the assessed liability related to nuclear waste management acting as the financing basis for the research programme, in accordance with the Nuclear Energy Act, is officially ratified only at the end of January. 3 Detailed objectives of the KYT2010 research programme The content of the research areas and themes respective to the KYT2010 programme are outlined in the following section. The spheres respective to the research themes should provide answers to currently known, essential questions related to nuclear waste management. The research projects should, by reference to their comprehensiveness, be the sort that they are sensible to realize from the perspective of available resources. The most natural area for the research programme is in various application-neutral method development projects whose results will later be at the disposal of all actors in nuclear waste management.

11 0 According to the previous KYT programme, the research is distributed into strategic clarifications respective to nuclear waste management as well as into research areas connected with the long-term safety of the final disposal of nuclear wastes. The latter also contains, as a new subject, questions related to nonproliferation supervision. A new area of study rests in social clarifications. 3.1 Nuclear waste management: strategic clarifications Research assessing strategic alternatives in nuclear waste management lends support to the implementation-related reliability of Finnish nuclear waste management. With strategic clarifications, the aim is to ensure a national foundation of know-how in the realization of nuclear waste management, also under changing circumstances (Fig. 2). Although our country is progressing with intent and determination towards the final geological disposal of spent nuclear waste, our eyes must be kept open to the possible alternatives in the event that the current plans may not be fulfilled. In this connection, Finland must be open for the international discussion going on with respect to strategic options. Strategic studies of nuclear waste management Fundamental options in nuclear fuel cycle and nuclear waste management RESEARCH PROJECTS General safety principles in nuclear fuel cycle and nuclear waste management Nuclear waste management costs, transport of nuclear wastes, operating waste, decommissioning of nuclear power plants Fig 2. Strategic studies in the KYT2010 programme Questions related to basic policies of the nuclear fuel cycle and nuclear waste management are, for example, the clarifications linked to partitioning and transmutation (P&T) or long-term storage. In recent times, international discussion has also been generated on

12 1 regional fuel recycling centres argued on the basis of intensifying non-proliferation supervision. In our country, there is reason to follow the development occurring in the international research field in these areas. Involvement in general international projects requires a sufficient degree of personal expertise. Common safety concerns affecting the nuclear fuel cycle and nuclear waste management are, among other things, the central principles of safety and radiation protection inspections, the reversal of final disposal and illicit entry into the final disposal facilities. General safety questions represent the sort of thinking which is behind, e.g., the selection of the final disposal concept and the specification of safety criteria. To the strategic clarifications may be added, in addition to the safety clarifications connected with alternative technical options and cost clarifications of nuclear waste management as well as the transport of nuclear wastes, the management of power plant wastes and the decommissioning of nuclear power plants. Monitoring the international development work (EU, IAEA and NEA) with regard to these themes is justified. 3.2 Final disposal of nuclear wastes: safety assessment The long-term safety of the final geological disposal of spent nuclear fuel is the most pivotal research area of the research programme. Long-term safety is assessed by means of quantitative safety analyses, but the safety case for final disposal as a whole also contains other, less mathematical safety arguments. Through using various safety argument, the aim is that others beside nuclear waste management specialists are themselves capable of assessing the safety of final disposal. The KYT2010 programme focuses on the individual safety concerns of the final disposal of nuclear wastes by improving analysis readiness and reducing, in this respect, essential uncertainties. The purpose is not to formulate a complete safety analysis. The research area is distributed in accordance with Fig. 3 into three themes: Engineered barrier systems, bedrock and groundwater, and the release and transport of radio nuclides. The safety questions associated with these broad themes are examined in the following generally and in a more detailed manner in the annex.

13 2 Safety assessment of final disposal concerning nuclear waste Bedrock and groundwater groundwater flow groundwater chemistry rock mechanics glacial cycles Research projects Engineered barrier systems final disposal canister benonite buffer and tunnel backfill Release and migration of radio nuclides near field far field biosphere Fig. 3. Final disposal of nuclear wastes: safety assessment in the KYT2010 programme. The final disposal canister as well as the bentonite buffer and tunnel backfill make up the engineered barrier system. The long-term canister is the most important single engineered barrier in the Finnish final disposal concept for spent fuel. The most important task of the bentonite buffer is to ensure favourable conditions for the long life span of the canister. The task of the backfill and sealing structures is to prevent the formation of groundwater flow through channels in the excavated areas. The spent fuel matrix also functions as an engineered barrier for radio nuclides, though it is not an engineered (built for disposing) barrier in the same sense as that previously mentioned. The groundwater flow, groundwater chemistry, rock mechanics and impacts of ice ages are all respective to the bedrock and groundwater. The groundwater flow functions as a carrier of mass flows in the bedrock and, this being the case, the modelling of the groundwater flow, acts as the basis of migration studies. The groundwater chemistry conditions and groundwater flow are important from the perspective of the durability of the engineered barrier and the transport of radio nuclides. The rock mechanical measurements and simulations are important in connection with the construction and operation of the final disposal facilities, but rock mechanical questions are also linked with long-term safety. The ice age impacts, in particular, glaciation, permafrost and the depressing of the earth s crust incur fundamental changes in the bedrock, of

14 3 which the most significant in terms of safety are linked with groundwater flow, groundwater chemistry and rock movements. The release and transport of radio nuclides cover the research on the transport occurring in the near and far field as well as the biosphere. By transport in the near field is meant the transfer of radio nuclides found in the spent fuel assemblies with the canister and bentonite buffer forming a complete whole, through the rock fissures after the impermeability of the canister has been lost and water contact has formed between the fuel and the rock fissures. By far field transport is meant the transport of radio nuclides which have passed from the near field to the rock fissures into the boundary layers of the geosphere and biosphere primarily with the flow of groundwater. In biosphere modelling, it is primarily the human living environs that are studied. 3.3 Studies of Social Impacts In the public research programme (JYT2001) preceding the KYT programme, social research was included (Rasilainen 2002a). At the time, the subject was connected with Posiva s policy decision application concerning the final disposal of spent fuel, which was linked to social discussion and the statutory hearing procedures. In the previous stage of the KYT programme, there was no longer any social research, since after the policy decision was made the theme was no longer topical in the same way. The next big stage in Finnish nuclear waste management shall be the construction license process for Posiva s final disposal facility starting in An environmental impact assessment report (EIA) will be updated in the same procedure. For this reason, it is possible that during the ending part of the research programme in particular it will be appropriate to earmark funding for clarifications limited to social content, e.g., the acceptability of the final disposal facility. 4 Research programme: reportage and communication This report is the framework programme of KYT2010 programme for the period The report presents the points of departure for the research programme as well as its basic targets, and a description of the organization of the programme is outlined. The starting points for the research programme are derived from the future challenges, current situation and former research programme history.

15 4 A detailed research plan for the entire research programme is made annually on the basis of the research proposals accepted for financing. The progress of the individual research projects is monitored in three interim reports. Each year, an annual report on the level of the entire research programme is prepared for the year in question on the implementation of the research plan and its pivotal results. The final realizations of project-specific goals are also examined in the report. For the research programme s internal exchange of information, thematic seminars on various subjects are arranged. The purpose in these is to illuminate perspectives linked with the selected theme from the perspective of both the research facilities and the final users of the findings. The seminar concentrates on only one theme at a time, so that it is able to handle it with maximum thoroughness. The publishing of general research results at international conferences in the field and in high-standard periodicals is encouraged. International publishing is important from the perspective of the individual researcher, because in Finland the researcher is frequently the best specialist in his/her field, and expert feedback on the research results is not always easy to obtain from the homeland. It is worth to publish good research work internationally not only due to the quality assurance connected with such printing but also because the scientific community in the field is thereby kept up-to-date on Finnish research. There is good reason to keep the international scientific community freshly informed about our circumstances already due to the fact that specialists from top-level international research are occasionally needed to assess our country's nuclear waste management plans. Both STUK and Posiva have, in their own work, international top-level specialists as additional support. The research programme s website ( functions as a pivotal communication point both within the research programme and between the research programme and the outer world. These web pages feature reportage on the entire research programme and information distribution starting with the framework programme. The website offers links to the home pages of all organizations participating in the research programme as well as those of the most pivotal international organizations. Links are added to the website to the most essential publications concerning individual research projects. A compact English-language version of the website is also being made.

16 5 The KYT2010 research programme functions as a significant national data transfer forum between the research networks in nuclear waste management. One of the components of the information transfer is the announcements of the research programme always made after the steering group meeting and at other times as well when there is something special to communicate. At the end of the programme period, an English-language final report covering the entire period of the research programme is prepared. 5 Cooperation Due to the limited resources of the KYT2010 programme, the research carried out therein must be coordinated well with other nuclear waste research going on in Finland to avoid possible overlapping and to cover possible blind spot areas. Only in examining the entire Finnish research field it is possible to ascertain actual national know-how and its potential need for development. It is particular important to be knowledgeable about the content of Posiva s research program, because Posiva s research budget is significantly larger in comparison to that of the KYT2010 programme. In this respect, regular communication helps in both directions. KYT2010 represents independent research which does not directly target the projects of Posiva and the power companies or the direct clarification requirements demanded by safety supervision. Although KYT2010 is indeed a national research programme, the research work itself is international in character, starting in practice with the networks specific to individual researchers. There is an endeavour to encourage substance-oriented international cooperation in individual research projects, e.g., participation in relevant EU projects or other international research projects, since in these access is available to large multi-field integers which would be beyond the reach of mere Finnish funding. In cross-disciplinary international projects, it is possible to obtain entirely new research ideas, because they offer the possibility to get acquainted with the methods of other research groups functioning in the field. EU nuclear energy research occurs within the sphere of the Euratom Treaty. Euratom s framework programmes represent

17 6 essential tools in the EU's nuclear energy research. The 6th framework programme, now in progress, will end in 2006 and the next one will cover the years At the beginning of 2005, Finns in the framework programme were involved in 16 projects, of which 5 can be seen as focused on nuclear waste management (ACTINET, CETRAD, ESDRED, FUNMIG, NF-PRO). A national support group serves as an aid to the Finnish participants in the Euratom framework programmes. The KYT programme projects have so far not been an active part of the Euratom framework programmes. Given the new potential research instruments, e.g., the Technology Platform and/or the Joint Undertaking, which is currently under development, this sort of participation may become feasible. Via the KYT2010 programme, it is possible to apply for part-financing from the Fund for EU projects which thematically suit this framework programme. There is good reason to continue participating actively in the future as well in international specialist work groups, because it is possible through these to effectively communicate the overall status of the nuclear waste programme and nuclear energy research to the central organizations in various countries. Conversely, data is quickly obtained via the same on the general circumstances of other countries formulating nuclear waste management. Traditionally, the OECD/NEA specialist groups have already been pivotal to Finland in this respect.

18 7 Annex Segmentation of safety research contents In this annex, a more detailed outline of the possible research themes connected with the safety of the final disposal of nuclear wastes is presented. Themes are mentioned herein in connection with which significant clarification requirements are still significant. The list is not, however, intended to be all-embracing, and research themes not included herein can also be accepted into the KYT2010 programme. The objects directly relevant to Posiva s clarification obligations have been eliminated from the outline, such as the Olkiluoto-based studies and the engineering/technical planning specific to the final disposal concept. ENGINEERED BARRIER SYSTEMS The activity inventory for spent fuel assemblies makes up a term of reference for safety analysis. The fuel matrix functions as an engineered barrier for the radio nuclides bound to the same. Various alternatives have been presented for the conceptual model particular to the solubility/disintegration of spent fuel, the applicability of which is being studied. The rapidly releasing radioactive component for highly combustible fuel is another important research target. These studies can only be performed in Finland rather restrictively, as they generally require hot cell research. By means of natural analogy research, it is possible to obtain for the most part confirmation data on the solubility of uranium under final disposal conditions and determine the behaviour of the repository from the time perspective of millions of years. The task of the final disposal canister is to isolate the spent fuel from the environment for a long period of time. It is the most important single engineered barrier in the Finnish final disposal concept for spent fuel. The canister can in principle become damaged primarily via chemical corrosion, external mechanical stress or a combination of these processes. Potentially appropriate research themes linked with assessing the service life of the canister in the KYT2010 programme are: copper stress corrosion: although the copper planned has not been evidenced to be sensitive to stress corrosion under final disposal conditions, the long time-frame causes uncertainty; through better understanding of the mechanisms, the

19 8 possibility of stress corrosion could be excluded more reliably than at present copper pitting: the understanding of pitting in sulphide/sulphate environments is not as solid as with chlorides creep resistance with regard to the canister material: creep resistance, particularly in friction-tap welded copper, should be studied under conditions which correspond to tests up to this point under actual final disposal conditions (pressure, temperature, duration). In addition, the possibility of environmentally-assisted creep should be examined. More precise assessment of the canister s service life requires modelling coupled with the various processes, in which the processes going on at the same time impact not only each other but mutually on the endurance of the canister. Up to this point, the processes have been studied for the most part separately, though the joint impact of corrosion and creep was empirically studied already during the first phase of the KYT programme. The corrosion research must be coupled with the study of near field chemistry, so that the test and modelling conditions are verified in accordance with the best possible data. The bentonite buffer surrounds the canister, and its most important task is to ensure favourable conditions for the long service life of the canister. The bentonite buffer is made of compacted bentonite. In order to function in the planned manner, favourable physicochemical properties must be obtained for it during the saturation stage and it must preserve them for a very long period. The task of the backfill and sealing structures is to prevent the formation of groundwater flow through channels in the excavated areas. Research themes potentially suitable for the KYT2010 programme relating to the operational capacity of bentonite and backfill are: the saturation of the bentonite buffer after the sealing of the repository bentonite buffer yield capacity in rock movements and loadbearing capability heat transfer from the canister via the bentonite buffer to the rock (during water saturation) the mineralogical adaptation of the bentonite (due to the effect of high ph or groundwater elements) bentonite buffer gas permeability erosion of bentonite and backfill over the long term operational capacity of backfill in saline groundwater environs

20 9 The behaviour of bentonite and backfill can be modelled mathematically. Analyses are need for the modelling source data; for instance, from laboratory tests, in situ tests in rock laboratories (Äspö, Grimsel) and natural analogies. A precise mathematical description requires coupled THMC modelling in which the simultaneously affective processes of temperature (T), hydrology (H), mechanics (M) and chemistry (C) are involved. This demanding type of modelling has been developed in Finland only during the first stage of the KYT programme, and the work is still on-going. BEDROCK AND GROUNDWATER Groundwater flow in the bedrock acts as a carrier of mass flows. Groundwater flow modelling is required in specifying mass flows in the near field, the transport of radio nuclides in the bedrock and the numbers and concentrations of radio nuclides escaping into the biosphere. Suitable, more general research themes for the KYT2010 programme as connected with groundwater flow are: a better combination than currently for modelling concepts of various scales and types (stochastic, continuous medium, separate zones) modelling of close-to-surface flow and linkage with the modelling of deeper groundwater flows transients caused by increasing land elevation The groundwater chemistry conditions and groundwater flow are important from the perspective of the durability of the engineered barriers and the transport of radioactive agents. Suitable, more general research themes for the KYT2010 programme as connected with groundwater chemistry are: better mutual linkage between groundwater chemistry and flow modelling than at present modelling of microbe processes: nutrient sources, linkage with dissolved gases, reducing capacity niche filler research as an indicator of geochemical evolution. The subjects mentioned could in principle be clarified by means of paleohydrogeological research data as well as that obtained from rock laboratories. The rock mechanical measurements and simulations are important in connection with the construction and operation of the final disposal facilities. Mechanical questions are also linked with longterm safety. More general, potentially appropriate research themes for the KYT2010 programme connected with rock mechanics and

21 0 obtained e.g. through research data from the rock laboratories which could be clarified include: characterization of the excavation disturbance zone, for instance, from the perspective of the transport of radio nuclides and bentonite erosion solid rock deformation and emergence/advancement of fissures round the excavated space (the subject concerned has been studied during a former stage of the KYT programme) thermomechanical behaviour of the rock fault shifts Ice age impacts, in particular glaciation and permafrost induce fundamental changes in the bedrock. From the perspective of the safety of the final disposal, the most significant changes are connected with groundwater flow, groundwater chemistry and rock shifts. By means of theoretical inspections based on general geological data, it is possible to obtain the order of magnitude assessments particular to ice age impacts. From the impacts perspective, for support more precise estimates require field study data from the representative areas. Suitable, more general research themes for the KYT2010 programme as connected with ice age impacts are: the emergence and movement of saline groundwater layers during glaciation and permafrost cycles the effects of glacial melt water, for instance, oxygenation capacity rock shifts during the late stage of an ice age The final disposal site of spent nuclear fuel comes under the jurisdiction of international and national non-proliferation supervision, and monitoring is being initiated already during the construction stage of the underground research facility (ONKALO). The most essential target of non-proliferation supervision is to detect and prevent the unauthorized removal of nuclear elements from the final disposal facility both during its operation and after it is sealed. In planning the applicable supervision methods, it should be taken into account that the research and accumulated databases used in characterizing the final disposal site can also be incorporated for the requirements of non-proliferation supervision non-proliferation supervision can support safety monitoring (intrusion prevention) but must be realized in the manner that it does not weaken the safety of final disposal (intrusive methods)

22 1 RELEASE AND TRANSPORT OF RADIONUCLIDES By near field transport is meant the transfer of radio nuclides in the spent fuel assemblies forming the canister and bentonite buffer as a whole into the rock fissures. The prerequisite of this transfer is that the impermeability of the canister has failed (e.g., a small hole) and the canister has filled with water. The term near field refers to the repository and the bedrock environs whose conditions have been disturbed. Generally in near field modelling, there is the assumption that radio nuclides have dissolved into the water in a damaged canister and then, via the leakage point in the canister, diffused into the bentonite and further into the rock fissures. In addition, it is conceivable that radioactive agents are released into the rock as a result of a discharge caused by the pressure of the corrosion gases generated in the damaged canister. Precise modelling of the behaviour of the defective canister under final disposal conditions is demanding, as it requires coupled analysis of several different types of processes (corrosion processes, dual-phase water processes and release, solubility, speciation, diffusion and sorption processes). By experimental research is meant securing support for modelling primarily on the part-process level. More general suitable research themes for the KYT2010 programme as connected with near field transport are: conditions for the sealing of the final disposal facilities during the next transient stage: in particular, the duration of the oxygenated phase, temperatures and microbes in the near field the chemical conditions in the damaged, water-filled waste canister (for instance, the composition of the bentonite pore water) transport of the organic colloids through the bentonite modelling of gas discharges impact of corrosion products on the behaviour of the damaged canister and bentonite buffer. By far field transport is meant the movement of radio nuclides which have passed from the near field to the rock fissures into the boundary layers of the geosphere and biosphere. Movement occurs mainly with the groundwater flows. The term far field refers to the bedrock farther away from the final disposal facility, where the conditions have remained undisturbed.

23 2 The conceptual transport model utilized in the safety analysis is fundamentally based on the far field transport description, using two terms: groundwater flow resistance and retention factor. The specification of the parametric values contained in flow resistance is difficult due to, for instance, the heterogeneity of the bedrock. Their specification must be performed primarily at the final disposal site. By means of analyzing more general research data, e.g., obtained from the rock laboratories, it would be possible to shed light on uniformities linked with flow resistance, e.g., scaling rules and parameter correlations. The conceptual model based on the retention term has been criticized as too simplistic. Modelling which is more process-oriented (diffusion, ion exchange, surface complexing, depositing reactions) has been proposed so that it is possible to take into account, for instance: groundwater chemistry changes and impacts on the retention term. In addition, suitable, more general research themes for the KYT2010 programme are: retention in rock porosity as an impact of heterogeneity reactive geochemical transport modelling: testing of models and acquisition of source data sorption into bacteria-derived minerals, e.g., iron oxides (biosorption) colloid movement, e.g., bentonite as a source of colloid. The transport studies on radio nuclides have had a significant role in the KYT research up to this point, but reactive transport modelling has not been developed systematically. In biosphere modelling, the emission rates of radionuclides from the geosphere into the biosphere (Bq/a) are converted on the basic of susceptibility analysis into dosage rates (Sv/a). Biosphere modelling is required because the Finnish safety criteria set by STUK are based on the dose rate. In the YVL 8.4 guideline, STUK has specified nuclide-based emission rate limits for longer inspection period, but the dosage limits remain included in the criteria for an inspection period of a few thousand years, which period is specific to the best predictions. A more general research theme which could potentially suit the KYT2010 programme, is radiation protection for other organic nature than that respective to human beings. This theme is currently the target of vigorous international attention. STUK is participating in a research project concentrated on this International Commission on Radiological Protection (ICRP) theme.