Speaker
Description
During recent years, there has been increasing interest in innovative reactor concepts, which would bring better efficiency and ability to “burn” actinides from spent nuclear fuel in order to minimize the amount of radioactive waste to be disposed in deep geological repositories. One of the most promising ones are molten salt reactors, where the salt in molten form serves not only as coolant, but can also be a fuel carrier, so the fuel would be dissolved in the coolant. In order to determine the fundamental characteristics of salt environment for use in nuclear reactor, the physical and chemical features of salts have to be determined very precisely. There were mainly investigated two groups of salts – fluorides and chlorides. According to obtained results so far, both are suitable for use in molten salt reactor, but chlorides are much easier to work with since they are in general less chemically aggressive. Despite great progress in research, there are still some gaps which need to be addressed. One of them is neutron data for most common chloride salts, especially in energies above 10 MeV. In order to perform such research activities, experimental salt assembly has been created and neutron spectra in several experimental channels has been investigated by using gold activation detectors. Since gold shows relatively low cross-section for n, reaction at higher energies, the local moderation has been considered. The main aim of this study is to identify the most suitable moderator material which will perform local moderation around the detectors and therefore provide better results through increased reaction rate, but without moderating of surrounding fast neutron field. In order to achieve that, Monte Carlo calculations using MCNP code together with various nuclear data libraries have been performed. Following to that, calculated results have been validated by experimental results which provided sufficient data for meaningful discussion.
