Entwicklung einer Rechenmethode zur HTR-Auslegung im Rahmen des Programmsystems RSYST und deren Erprobung an der kritischen Anlage "KAHTER"

In this report the neutron- and reactor physical aspects of the high temperature pebble bed reactor are studied. For this purposeappropriate HTR-nuclear date sets are generated and applied in a calculation model, which is developed an the basis of neutron transport and diffusion theory. This model inoludes the complete reactor calculation for determination of neutron flux, reactivity and reaction rates. This reactor caiculation is based an following: evaluation of resonance absorption in double heterogeneity, cell calculation in spherical geometry, tone spectral calculation and subsequent 2-dimensional diffusion calculation. All calculations are performed in the modular program System RSYST, which accomodates simplified treatment of reactor physics problems through its data transfer and treatment techniques and through its calculations control features. The results of the calculations are compared with measured values of different core configurations of the critical facility for the high temperature pebble bed reactor (KAHTER). This comparison shows how a critical facility is used to verify and to adjust theoretical modeln for evaluating critical massec, neutron flux density and space dependent reaction rates