Fission-product measurements in the SCARABEE mono and seven-pin loss-of-coolant experiments

Abstract

During the course of the ‘SCARABEE’ experimental programme, the primary objective of which was to study the fuel and thermohydraulic behaviour, fission-product concentration were measured by a number of techniques. These included delayed neutron monitoring, total gamma, gamma spectrometry, sodium sampling and analysis and gas sampling and analysis. This paper describes the methods used to evaluate the data from these measurements and discusses the results. The theoretical models for fission-product generation and release are described and compared with the experimental data, and a critical examination of the techniques and results leads to recommendations for improvements in methods for future experiments. Conclusions are drawn relating to fission-product behaviour in LMFBRs. It is recognized that the experiments do not model closely the power reactor situation, but it is argued that the results obtained, particularly from delayed-neutron measurements, do provide a useful pointer to the value of fission-product monitoring in limiting fuel damage from local fuel overheating faults.