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[en] In the period since Germany's experimental final repository ASSE was closed in 1978, around 5000 drums of conditioned plutonium-bearing radioactive waste from mixed-oxide (MOX) fuel fabrication have accumulated in the interim storage facilities of siemens AG's MOX fuel fabrication plant in hanau, Germany - formerly ALKEM GmbH, now siemens decommissioning projects (siemens DP). Another 5000 drums will arise in the course of decommissioning and dismantling the MOX plant which has now been underway for some months. The German Federal Government estimates that a geologic repository will not be needed for at least another 30 years. Therefore siemens is taking the necessary steps to enable radwaste to be safely stored in aboveground interim storage facilities for a prolonged period of time. Conditioning of MOX waste by cementation in drums was started in 1984. Permission to keep the drums in interim storage for a longer period of time in their current form would be extremely difficult to obtain as their corrosion resistance would have to be demonstrated for a further 30 years. The present goal is therefore to create a waste form suitable for interim storage which needs no maintenance over a long-term period, incorporates state-of-the-art technology and satisfy the requirements currently specified for final storage at the ''konrad'' repository [1]. The goal can be attained by immobilizing the cemented waste drums in concrete inside steel ''konrad containers'' (KCs). The KCs themselves and the concrete backfill represent two further barriers which not only serve as radiation shielding but also protect the drums against corrosion as well as any possible release of radioactive materials in the event of accidents occurring during interim storage. (orig.)

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[en] At the mixed-oxide (MOX) processing facility formerly operated by ALKEM GmbH in Hanau, Germany - which was taken over to Siemens in 1988 and renamed Siemens' Hanau Fuel Fabrication Plant, MOX facility - around 8500 kg of plutonium were processed to make MOX fuel rods and fuel assemblies since production started in 1965. After shutdown of the facility by the authorities in mid-1991 for political reasons, the remaining nuclear fuel materials were processed during the subsequent ''cleanout'' phase starting in 1997 into rods and assemblies suitable for long-term storage. The last step in cleanout consisted of ''flushing'' the production equipment with depleted uranium and thoroughly cleaning the gloveboxes. During cleanout around 700 kg of plutonium were processed in the form of mixed oxides. The cleanout phase including the subsequent cleaning and flushing operations ended on schedule in September 2001 without any significant problems. Starting in mid-1999, the various glovebox dismantling techniques were tested using uncontaminated components while cleanout was still in progress and then, once these trials had been successfully completed, further qualified through use on actual components. The pilot-phase trials required four separate licenses under Section 7, Subsection (3) of the German Atomic Energy Act. Thanks to detailed advance planning and experience from the pilot trials the individual dismantling steps could be described in sufficient detail for the highly complex German licensing procedure. The first partial license for decommissioning the MOX facility under Sec. 7, Subsec. (3) of the Atomic Energy Act was issued on May 28, 2001. It mainly covers dismantling of the interior equipment inside the gloveboxes a well as the gloveboxes themselves. Actual decommissioning work inside the former production areas of the MOX facility started on a large scale in early September 2001. (orig.)

[en] The framework plan gives an account of the current status and further, still necessary research and development work for the elaboration of scientific fundamentals and for the development of methods for the safety analysis of a future Federal radwaste repository for heat-releasing radioactive waste in salt formations. The framework plan is subdivided into a review of results and a part with project descriptions. The review of results covers the four subject areas: Scenarios and programs, chemical effects in the close-in area, geotechnical and physical effects in the close-in area, transport processes in the geosphere. (orig./HP)

[en] The effect of anisotropic thermal expansion of (1 anti 100)-oriented sapphire substrates has been investigated with respect to magnetostrictive anisotropy in sputter deposited (Tb_0.27Dy_0.73)_1-xFe_x single layers and [(Tb_0.27Dy_0.73)_0.27Fe_0.73 + 2 at% Zr]/Nb multilayers. It is found that the thermally induced anisotropic film stress due to the anisotropic thermal expansion of sapphire can result in a magnetostrictive inplane transversal anisotropy. This may be of major interest for giant magnetostrictive thin film applications in microsystems where reversible magnetomechanical switching elements are required. Magnetic, magnetostrictive and microstructural (XRD) experiments have been performed. Magnetostriction has been measured at room temperature using the cantilever method with maximum inplane applied fields of 0.8 T. Ratios λ _parallel /λ _{perpendicularto} of magnetostrictions in fields applied parallel and transversal to the cantilever's longside ([0001]-substrate direction) are taken as a measure of the magnetostrictive inplane anisotropy. We found that λ _parallel /λ _{perpendicularto} (0.8 T) is varying with the microstructure (average grain sizes d) resulting from different heat treament. It is assumed that within the competition of magnetoelastic (favouring an inplane transversal anistropy) and magnetocrystalline interactions (favouring an inplane isotropy) the second will dominate for larger average grain sizes. This is indicated by comparison of nanocrystalline films on sapphire with different grain sizes d: amorphous or nanocrystalline (d < 25 nm) films exhibit a transversal magnetostrictive anisotropy (λ _parallel /λ _{perpendicularto} (0.8 T) >> 2) while stable crystalline films show magnetostrictive inplane isotropy (λ _parallel /λ _{perpendicularto} (0.8 T) ∝ 1). (orig.)

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[en] In the early and mid-1990s, a series of decisions had to be made - partially as a result of political requirements but also, in some cases, for economic reasons - to permanently shut down four facilities operated by the Nuclear Fuel Cycle Division of Siemens' Power Generation Group (KWU). 1989 saw the closure of the hot cells in Karlstein in which Germany's most extensive post-irradiation examinations of fuel assemblies had been carried out since 1967. In 1994/95, manufacture of gadolinium-bearing uranium fuel assemblies was abandoned at the Siemens Karlstein Fuel Fabrication Plant which had been in operation since 1963. At the Siemens Hanau Fuel Fabrication Plant, the facilities for manufacturing mixed-oxide (MOX) fuel assemblies and uranium fuel assemblies were permanently shut down in 1991 and 1995, respectively. The uranium processing facility had been in operation since 1969, and the MOX processing facility since 1970. Shutdown and decommissioning of these four facilities have mainly been proceeding in the following stages. First of all the facilities are cleaned out and all process equipment is removed. Then the auxiliary and support systems are dismantled. Finally the buildings are decontaminated and, in some cases, demolished. Possibly contaminated soil will be removed and the site restorated, after which it is released for unrestricted use and is no longer subject to the licensing requirements of the German Atomic Energy Act. Nuclear fuel materials as well as a few of the process components have been given to other nuclear fuel manufacturers. (orig.)

[en] Four Siemens-owned German fuel cycle facilities are being decommissioned at the Hanau and Karlstein sites. Decommissioning of one of these facilities has already been completed. The facilities comprise three fuel fabrication plants and a facility for post-irradiation investigations of fuel assemblies. In each case the actual decommissioning phase was preceded by cleanout. Extensive preparatory investigations and planning, including licensing procedures, had been necessary. In some cases new measuring techniques and systems had to be developed and waste processing systems erected. In addition to providing a general survey of the different conditions and procedures involved, the MOX facility is used in this paper as an example for presenting these activities in greater detail. This includes the concept of immediate conditioning of radwaste for maintenance-free long-term interim storage (storage for several decades until a repository is available) in such a way as to also meet the requirements for shipment and final disposal without any need for further actions. A number of lessons have been learned and recommendations derived from the many years of decommissioning work at the four facilities. (orig.)