[en] The meeting was organised under the auspices of OECD Nuclear Agency's International Information Exchange Programme on Actinide and Fission Product Partitioning and Transmutation. In the original announcement for the meeting the following sessions were proposed: 1) Concepts of accelerator-based transmutation systems, 2) Nuclear design problems of accelerator-based transmutation systems with emphasis on target facilities and their interfaces with accelerators, 3) Data and methods for nuclear design of accelerator-based transmutation systems, 4) Related cross-section measurements and integral experiments, 5) Identification of discrepancies and gaps and discussion of desirable R+D and benchmark activities. Due to the large number of papers submitted it was necessary to split session 2 into two parts and to reassign some papers in order to balance the sessions more evenly. No papers were submitted for session 5 and this was replaced by a summary and general discussion session. These proceedings contain all 30 papers in the order they were presented at the meeting. They are copies of the duplication-ready versions given to us during or shortly after the meeting. In the Table of Contents, the papers are listed together with the name of the presenter. (author) figs., tabs., refs

[en] Published in summary form only

[en] A new equation of state for the expansion adiabat of the low density explosive charge used in the COVA scale model tests is derived using impulse and strain data from test WT0 together with reported data from associated detonation tests. Use of this equation, combined with realistic modelling of the COVA experimental assembly, can successfully resolve many of the discrepancies between measured and calculated data observed in the series. (orig.)

No abstract available

[en] The minor actinides in the high-level waste from LWR spent fuel are contributors to the long-term radiological risk. In the present study a theoretical transmutation system for minor actinides is investigated which relies on the direct use of high-energy fission and spallation reactions alone. The advantage of utilising the high-energy reactions themselves as transmutation processes are the high fission probability and the tendency to directly reduce the mass of the bombarded nuclei of build-up of undesirable higher reaction products). The purpose of the study is to find the theoretically achievable reduction of the long-term risk by assuming different recycling and partitioning schemes. The transmutation system is simulated by a quasi-infinite minor actinide target irradiated by 1 GeV protons. It is shown that the reduction of the radiological toxicity is highest for a system in which all spallation products are recycled. Beyond 200 years the overall toxicity decreases by 3 orders of magnitude at 100 years compared with the direct decay of the original minor actinide mixture from LWR spent fuel. The disadvantages of the above theoretical transmutation system are a poor energy balance and the necessity of a powerful proton accelerator. However, the system provides a very intense neutron source which can be used to breed fissile material for high-conversion reactors or to transmute fission products with very low capture cross-section. (author) 10 figs, 9 tabs

[en] At the Paul Scherrer Institute (PSI), hybrid systems with a fast neutron spectrum are extensively investigated. The high-energy particle interaction is treated using the Monte Carlo method. For the transport of neutrons at low energies a deterministic approach is adopted, together with modern nuclear data libraries. (authors). 14 refs., 1 figs

[en] The response of an LMFBR roof cover to HCDA loadings is examined using a combined 2D/3D modelling approach. A generic 3D roof design of box-type construction is adopted and analysis under specimen loads carried out using the finite element program ADINA. The reactor tank and all internal components below roof level are assumed axisymmetric with the containment code SEURBNUK-EURDYN employed to follow the accident progression. An interface between SEURBNUK-EURDYN and ADINA is provided via a 2D simulant roof model, chosen to match the principal response characteristics of the 3D roof, to enable any interaction effects occurring during impact to be assessed. (author)

[en] The results of detailed steam entry calculations for a realistic reactor model are reported. The calculations predict that the effect of steam entry into a 300 MWe GCFR fueled with normal Pu mixed oxide fuel is negative in the whole range of interest. The effect is very sensitive to the method used for compensating the excess reactivity to obtain criticality before steam ingress occurs. Steam entry reactivity is sensitive to fuel enrichment and boron control. Changes in the isotopic compositions of Pu can give raise to important changes of the steam entry effect. A small amount of 237Np added to the fuel can considerably improve steam entry reactivity without noticeably deteriorating breeding ratio or affecting reactor operation

[en] The response of an LMFBR roof cover to HCDA loadings is examined using a combined 2D/3D modelling approach. A generic 3D roof design of box-type construction is adopted and analysis under specimen loads carried out using the finite element program ADINA. The reactor tank and all internal components below roof level are assumed axisymmetric with the containment code SEURBNUK-EURDYN employed to follow the accident progression. An interface between SEURBNUK-EURDYN and ADINA is provided via a 2D simulant roof model, chosen to match the principal response characteristics of the 3D roof, to enable any interaction effects occurring during impact to be assessed. (author)

[en] In view of the considerable amount of ²³⁷ Np produced as a by-product in nuclear power reactors, possible utilization of this nuclide in the nuclear fuel cycle has been studied. In particular, the performance of a gas-cooled fast breeder reactor as a neptunium burner was assessed. A strategy was developed and mass flows were computed for a denatured plutonium LWR strategy using uranium, plutonium and neptunium recycling. 10 refs