[en] Collective properties of even-even nuclei in the radium region are studied theoretically. Energy of the lowest collective states and reduced probabilities B(E2) and B(E3) of electromagnetic transitions between these states are mainly analysed. The excited states are treated as large-amplitude quadrupole and octupole vibrations coupled with each other. A large anharmonicity of the spectrum and a large value B(E3) of the transition from the first octupole excited state to the ground state are obtained, for octupole-deformed nuclei. A strong dependence of the results on the shape of the potential energy of a nucleus, treated as a function of its deformation, is stressed. (author)

[en] Research reactors are designed to produce in the core a neutron flux as high as possible, and to adapt the flux in response to the local energy requirements of experiments. This is why slow (thermal) neutrons generated outside the core are of importance, as they can be applied for scatter experiments using the beam holes, and for direct sample irradiation, whereas the fast neutrons in the core are of significance only to special purposes (mainly for the study of radiation damage). The thermal power generated in a research reactor is relatively low (typically lower than 50 MW) and in general is released unexploited. This is done because the temperature level of the thermal energy is very low, in order to achieve optimum core cooling and to meet experimental requirements, so that conversion to electrical output or for heating purposes is unattractive. Another reason is that any utilizable output from research reactors would be available at very irregular intervals only, due to the experimental time-table. (orig.)

[en] Reference core KKE7 could be defined and specified in all dimensions, materials, uranium density and distribution, control rod structure and central canal (for core control and guidance, and removal of D₂O). The effectiveness of the central control rod and of the cooling under the different operational conditions is largely known. Questions on the erection, control and guidance, anchoring and handling are answered with respect to the following components: Details of the D₂O reflector tank with central canal, internals and adjacent cooling structure. Mechanical design of KKE5 and KKE 7 with anchorings and guide system. Conception and comparisons of the power control rod with drive, linkage, absorber and Beryllium sequential controller. Fitting of emergency shutdown rods positioned in relation to the beam holes, the cold source and the cooling structure. Logistical studies on the compact core, control rod, emergency shutdown rods, instrumentation, central canal, beam holes and the D₂O reflector tank for operational refuelling, inspection and repair. (orig.)

[en] Papers presented at this Meting were divided into following sessions: safety, licensing and decommissioning of research and test reactors; new reactor facilities and upgrades of the existing research reactors; optimisation of operation and Utilisation; secondary neutron sources; neutron scattering techniques available at existing reactor facilities

[en] In this paper, a contribution given at the Kyoto University Research Reactor Institute to the temporal meeting on the design of the facilities for high flux, low temperature irradiation is summarized. The following five subjects were discussed. The project of modernizing the swimming pool type research reactor FRM with 4 MW power at Munich is to achieve relatively high thermal neutron flux, and an extremely compact core is designed. The existing low temperature irradiation facility (LTIF) of the FRM is the most powerful in the world, and has been successfully operated more than 20 years. The fast and thermal neutron fluxes are 2.9 x 10¹³ and 3.5 x 10¹³ /cm² sec, respectively. The experimental techniques in the LTIF of the FRM, such as a measuring cryostat, the mounting of irradiated samples and so on, are described. The installation of new LTIFs in connection with the projects of advanced neutron sources in Germany is likely to be made in the modernized FRM at Garching, in the spallation neutron source SNQ at KFA Juelich and so on. The interesting problems in fundamental and applied researches with LTIFs, and the unusual application of LTIFs are shown. (Kako, I.)

[en] A new national research reactor is planned in Germany which shall replace the existing FRM reactor at Garching. The new FRM-II will be optimized primarily with respect to beam tube applications but it will also allow the irradiation of samples etc. Because of the compact core reactor concept, which provides for a particularly small H₂O cooled reactor core in the center of a large D₂O moderator tank, high values of the thermal neutron flux can be obtained at only 20 MW power. This paper also discusses some of the features of the technical concepts of the new reactor

[en] A new research reactor FRM-II is planned for the University of Munich. It will replace FRM-I, which has been operating since 1957, and will provide a 50 times increase in thermal neutron flux for a five-fold increase in thermal power. There is a diverse range of applications for such a high intensity neutron source in European research. The FRM-II will have a compact core consisting of a single fuel element cooled with light water and surrounded by heavy water as moderator. A summary of the specifications is given. The reactor will use high density uranium silicide fuel containing high enriched U-235 (HEU). An intense thermal neutron flux of about 10¹⁵n/cm²s can be generated. In the interest of non-proliferation there is an international programme to convert all research reactors from HEU fuel to low enriched fuel. The designers of FRM-II claim, however, that HEU is essential to the successful performance of the reactor's role. (2 figures, 2 tables) (UK)

[en] The Technical University of Munich is currently designing-together with other research institutes and with industry-a new high flux research reactor to replace its old 4-MW swimming pool facility. This new national neutron source will be optimized primarily for beam tube applications of thermal (and cold) neutrons. The plans are to realize a particularly efficient source, i.e., to obtain high values of the thermal neutron flux in a large usable volume outside of the reactor core at a level of reactor power that has to be low for reasons of economy and public acceptance. These criteria can be best met by the concept of a particularly small, light-water-cooled reactor core surrounded by a large heavy-water moderator tank. The reactor power has been settled at 20 MW. The new U₃Si₂/Al dispersion fuel will be used with an uranium density of 3.0g/cm³ up to a 105.6-mm radius and with 1.5g/cm³ in the outer region to flatten the radial power density profile. The present status of the project is discussed

[en] None

[en] The project of the FMR-II reactor which is planned to be built at the Technical University of Munich (Garching, Germany) is described. The reactor will be used as a new neutron source which is supposed to satisfy the needs of research in Germany for the next three decades or longer. The core of the FRM-II reactor consists of a single fuel element 24 cm in-diameter with an active height of about 70 cm. The core contains about 8 kg of highly enriched uranium in the form of the aluminium-uranium silicide dispersion. The fuel elements is positioned in the center of a heavy water moderator tank. The moderator tank is located in the reactor pool containing light water. There are 10 horizontal and 2 inclined beam tubes which supply the experiments with neutrons of various spectra. As secondary facilities the reactor has 1 cold neutron source, 1 hot neutron source, 1 converter facility producing a fission spectrum, 2 silicon doping units, several pneumatic systems for specimen irradiations, 1 positron source and other installations and options. The total cost of the facility including a basic scientific instrumentation are estimated to 720 million German marks. 4 figs