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| Hauptseite > Publikationsdatenbank > Comparison of US/FRG accident fuel condition models for HTGR fuel failure and radionuclide release |
| Hauptseite > Publikationsdatenbank > Comparison of US/FRG accident fuel condition models for HTGR fuel failure and radionuclide release |
| Book/Report | FZJ-2016-05741 |
; ;
1991
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag
Jülich
Please use a persistent id in citations: http://hdl.handle.net/2128/12652
Report No.: Juel-2458
Abstract: This report describes cooperative work on HTGR safety research as agreed to in the "US/FRG Umbrella Agreement for Cooperation in OCR Development: Safety Research Subprogram Plan". The objective was to compare calculation models used in safety analyses in the US and FRG which describe fission product release behavior from TRISO coated fuel particles under core heatup accident conditions. The First step performed is the qualitative comparison of both sides' fuel failure arid release models in order to identify differences and similarities in modeling assumptions and inputs. Assumptions of possible particle failure mechanistns under accident conditions (SiC degradation, Pressure vessei) are principally the same on both sides though they are used in different modeling approaches. The characterization of a standard (= intact) coated particle to be of non-releasing (GA) or possibly releasing (KFA/ISF) type is one of the major qualitative differentes referring to the philosophy which the recently developed statistical model (Integrated Failure and Release Model for Standard Partieles) and the classical diffusion model, respectively, are based upon. Sirnilar models are used regarding radionuclide release from exposed particle kernels. In a second step, a quantitative comparison of the caleulation models was made by assessing a benchmark problem predieting particle failure and radionuclide release under MHTGR conduction cooldown accident conditions. Calculations with each side's referenee method haue come to almost the saure failure fractions after 250 hours for the core region with rnaximum core heatup temperature despite the different modeling approaches of SORS and PANAMA-1. The comparison of the results of particle failure obtained with the Integrated Failure and Release Model for Standard Particles and its revision which are used an both sides provides a "verification" of these models in this sense that the codes (SORS and PANAMA-II, and -IH, respectively) which were independently developed lead to very good agreernent in the predictions. Differences in radionuclide release fractions are basically related to a different degree of simplification in the description of certain phenomena in the models by empirical approach and to different input data whose derivation could be based upon different experiments. These differentes would need further study in order to be resolved.
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