Reactor tests of a neutron-flux regulation system based on layered compouns of pyrolytic graphite with cesium

This paper is concerned with the results of an experimental check of the absorption method of regulating the neutron flux density with the help of layered structures, the basis for which is given in [i]. Experimental investigations performed with the use of activated carbon-cadmium [ 2] and activated carbon--boron trifluoride [ 3] have confirmed the effectiveness of the absorption method, based on absorption of substances by the surface of solids. In contrast~to previously studied pairs, the absorbing screen in the case of layered structures is formed with absorption and penetration of neutron absorbing substances into the bulkof the structure of a neutron-transparent matrix, for example cesium in pyrolytic graphlte, In view of the fact that the use of different neutron absorbing substances greatly affects the neutron spectrum due to the different spectral dependence of the absorption cross section of sorbates, as well as the temperature regime of operation of the sorptlo n screen, it is necessary to perform thermal and reactor investigations of different sorption pairs in order to select the optimum composition for each specific problem.