[en] Automatic translation: ZUT-DGL means ''ZUT and the like''. It represents an amalgamation of programmes required for the calculation of resonance absorption cross-sections in GAM groups. Resolved and unresolved resonance integrals are calculated on the basis of basis of ZUT and TUZ /1,2/ are calculated. For heterogeneous arrangements of spherical fillings and rod arrangements with coated particle filling, the numerical calculations of the geometric probabilities can be carried out as in ZUT-DG /3/ and for interactions in and for the interactions in rod arrangements a calculation of calculation of Dancoff factors on the basis of DANCOFF-3 /4/ is carried out.

[en] Hahn-Meitner-Institut presented an overview concerning the HEU/LEU-conversion at the 15. RERTR-Meeting. Our last report at the 2.0 RERTR-Meeting dealt with the successful operation of the first mixed core. (author)

[en] Automatic translation: For a 3000 MW_th--OTTO spherical pile process heat reactor, the nuclear and thermo-hydraulic characteristics of the Equilibrium cycle specified. This is their first Design draft that works at an average power density of 5 MW/m³ fed with low-enriched uranium Burnup of 101,000 MWd/t and an average gas outlet temperature of 950°C were achieved.

[en] The design is described of a line for the analysis of plutonium and mixed (U, Pu) fuels. The design meets the requirement that the line should allow a continuous analysis of plutonium nuclear fuels using chemical methods oriented to oxidation-reduction titration techniques. This determined the nature of operations which should take place on the line. The specifications are given of the individual details as are parameters affecting the correct line operation in the analysis of plutonium fuels. (author) 7 figs., 2 refs

[en] We report our benchmark calculations performed with one- and two-dimensional S_N-codes in the adjoint mode. Special emphasis is put on multigroup treatment of neutrons in the high and low energy ranges including upscattering, taking account of hydrogen bound in polyethylene. Sensitivity studies show the effects of the steel wall and the stem of the proportional counter together with the influence of changes of the moderator density. The responses are compared with recent measurements. (orig./HP)

[en] The BER II is a swimming pool reactor and mainly used for neutron scattering experiments. The BER II has been operating since 1973, and was upgraded from 1985 to 1991 to increase the neutron flux. Hereby, the power was increased from 5 to 10 MW. In addition the core size was decreased and was then encompassed by a beryllium reflector. Finally, a cold source was installed. When the reactor restarted 1991 with HEU-fuel, we applied for a license to convert to LEU-fuel, which was granted in 1993. However, we still had to solve the problem of getting rid of our spent LEU-fuel assemblies. At that time, we also had about 30 HEU-assemblies on storage. This was the main reason why we only started conversion after August, 1997, when our HEU-fuel was used. At this point, we signed a contract with US-DOE dealing with the return of the spent fuel assemblies to the USA. Since then, at each refueling, we have exchanged 2 to 5 HEU-fuel assemblies by LEU-assemblies. Each time we had to perform several measurements to ensure for the necessary safety requirements. Even after the completion of the conversion in February 2000, we have to do this also for each pure LEU-core. These measurements and their results are presented in the following paper. (orig.)

[en] The BER II is a swimming pool reactor and mainly used for neutron scattering experiments. The BER II has been operating since 1973, and was upgraded from 1985 to 1991 to increase the neutron flux. Hereby, the power was increased from 5 to 10 MW. In addition the core size was decreased and was then encompassed by a beryllium reflector. Finally, a cold source was installed. When the reactor restarted 1991 with HEU-fuel, we applied for a license to convert to LEU-fuel, which was granted in 1993. However, we still had to solve the problem of getting rid of our spent LEU-fuel assemblies. At that time, we also had about 30 HEU-assemblies on storage. This was the main reason why we only started conversion after August, 1997, when our HEU-fuel was used. At this point, we signed a contract with US-DOE dealing with the return of the spent fuel assemblies to the USA. Since then, at each refueling, we have exchanged 2 to 5 HEU-fuel assemblies by LEU-assemblies. Each time we had to perform several measurements to ensure for the necessary safety requirements. Even after the completion of the conversion in February 2000, we have to do this also for each pure LEU-core. These measurements and their results are presented in the following paper. (orig.)

[en] The operation of the 10 MW research reactor BER II with pure HEU cores ended on July 27,1997. The conversion from HEU to LEU fuel was started with three LEU elements in the first HEU/LEU mixed transition core. The licensing and technical procedures are explained. All safety criteria according to the HEU/LEU-conversion license are fulfilled. Since August 26, 1997, the BER II is again in routine operation. (author)

[en] The BER II (Berliner Experimental Reactor) research reactor is a swimming pool type reactor located in Berlin, Germany. The reactor operates with a thermal power of 10 MW and is primarily used to produce neutrons for neutron scattering experiments. The conversion from HEU- to LEU-fuel elements began in August, 1997. At the last RERTR Meeting 1999 in Budapest, Hungary, Hahn-Meitner-Institut (HMI) presented a 'Status Report' on the conversion of 10 HEU/LEU mixed cores. In February 2000, HMI finished the HEU/LEU-conversion. Hereby, the first pure LEU-standard-core went into operation. Our second LEU-core just ends its operation at the end of July. The third LEU-core will be built up in the beginning of August. The average burn-up rate was improved from 50 - 55% (HEU) to 60 - 65% (LEU). Therefore, only 14 elements/year are now used instead of 28/year. The following report describes our first steps in building pure LEU-cores from mixed HEU/LEU-cores, as well as our initial experience using the pure LEU-cores. (author)

[en] For the complete conversion of the BER II core, 9 HEU/LEU-mixed-cores had to be built. The safety margins for each core had to be verified by measurements, which took about two weeks time, respectively. Leading to a loss in the experimental period for the scientists of about 25% (20 weeks), compared to the normal operation time of 35 weeks per year. For two cores, however, the reactor could only be operated with a maximum power of 9.5 and 7.0 MW, respectively. (author)