Development and Application of Nuclear Measurement Techniques

摘要

A study program was performed on the selection of high-temperature materials for use as passive neutronfield-measuring devices and of thermal-neutron shields for use in extreme nonnuclear environments. Seventeen candidate materials were investigated from which four compounds were selected as most suitable for hightemperature neutron detectors. Also, five high-temperature cements were investigated for possible use as binders in pellet fabrication, and two were found to be acceptable. A limited amount of information is given on the feasibility of replacing cadmium thermal-neutron shields with cadmium oxide shields in high-temperature environments. Facility calibration procedures and results are presented for the modified Ground Test Reactor irradiation chambers, pneumatic tubes, and standard-pile facilities. Also discussed is the interfacility comparison of sulfur-pellet calibrations conducted jointly with three other nuclear facilities. Preliminary results are presented of an experiment performed to reevaluate the counting efficiencies of the Nuclear Aerospace Research Facility end-window counters for commonly used foils. (Author)