No abstract available

[en] As a part of the HDR program, methods for coupled fluid-structural dynamics are being developed. On the fluid side the 2D finite difference code YAQUI has been modified (it became YAQUIR) and adapted to describe the fluid dynamics in the downcomer of PWR's. On the structural side for determination of the dynamic core barrel response the code CYLDY2 has been developed. In this code the core barrel is treated as a thin cylindrical shell fixed at the upper end and ring stiffened at the lower end. The mass of the lower end ring also simulated a part of the core mass. Both models have been successfully tested. Coupling has been achieved for a simplified structural model proving the correctness of the coupling procedure. The structural model CYLDY2 is based on Fluegge's shell equations and uses variational principles. The solution is a superposition of steady-state and transient eigenfunctions. Results indicate that for the relatively thin-walled core barrel of the HDR-experiments in most cases the local deformations are somewhat higher than the global deformation (beam model). The coupling of YAQUIR and CYLDY2 is performed by imbedding the structural model in the fluid model. Fluid velocities are parallel to the fluid/structure interface. The structure desplacements define the time and space dependent thickness of the two-dimensional fluid layer (2 1/2-dimensional model)

No abstract available

[en] Short communication

[en] Failed fuel element detection and location system adaptive for about all water cooled reactors is discussed. The system was originally constructed for and operated at the Heissdamfreaktor HDR. Sampling system and fission product measurement method used in the failed fuel location system are described

[en] The studies being performed on the HDR are intended to verify and, if necessary, optimize with respect to earthquake effects the methods of computation for the dynamic analysis of reactor pressure vessel, piping systems, soil, equipment and fluids. The program is divided into two parts: phase I 'low excitation level', and phase II 'high excitation level'. Phase I is characterized by the fact that mainly a linear vibration behavior is investigated experimentally with the stresses in the structures largely remaining in the elastic range. The results of the experimental studies of phase I are available for comparison with the results of theoretical studies carried out by means of the usual linear models. Phase II relates mainly to the assessment of the non-linear vibration behavior of the structures. The experimental studies are planned to go beyond the range of purely elastic material behavior. For this reason, it may be necessary in these theoretical studies to use computer models, or to develop new ones, which allow the treatment of non-linear material behavior and non-linear geometric effects. This becomes particularly important if non-linear effects have such significant consequences that an approximate assessment of the vibration behavior by linear methods will be no longer meaningful. The verification of methods and dynamic models by detailed comparison of calculated and experimental results is directed to: - the information about reliability of existing structural dynamic techniques and methods of measurement; the quantification of the influence of interactions between the soil and the containment structure and between the reactor pressure vessel or other circuit components and the pipes; the assignment of the techniques to their optimum fields of application; - the quantification of the influence on the vibration behavior of the parameters of materials, soil and design structure; - improved methods, especially for the assessment of non-linear effects

[en] The author surveys the HDR safety programme. This includes simulated breakdowns on a large scale (original dimensions). By comparing values the accuracy of the theoretical calculation can be demonstrated by the simulation results. The author illustrates the procedure using pipeline fractures as example. (orig.)

[en] A fire research program was started in FRG at the HDR plant to generate the necessary plant data for fire calculations and to verify the present know-how about fire scenarios and codes in a complex realistic environment. The HDR is able to generate a new database about fire characteristics in containment. The results of HDR fire experiments differ substantially from others known up to now. They were used to verify different types of fire codes on one experiment to initiate a code evaluation which makes calculation transferable from experiment to real plant behavior. (orig./HP)

[en] Published in summary form only

[en] A structural dynamic simulation was conducted to predict the structural response of a nuclear power piping system to severe thermal-hydraulic loads. The simulations were part of the series of 'blind' calculations sponsored as part of the Heissdampfreaktor Safety Research Program, Federal Republic of Germany. The results of one such simulation and comparison to experimental behavior is reported herein. (orig.)