THE DEVELOPMENT OF A THERMAL-NEUTRON-FLUX MEASURING INSTRUMENT

摘要

An instrument was developed to measure thermal neutron flux directly and automatically in the range from 10 13 to 1014 neutrons/(cm ) /sec) at ambient temperatures up to 600 F. Two prototype tests were conducted. Measurements made with this instrument are independent of gamma flux and, within a small error, independent of ambient temperature. The method depends on balancing the temperatures of an electrically heated balancing element and a fission-heated uranium-fueled sensing element. Thus, the instrument gives a direct measurement of fission-product power, produced by a known amount of uranium.nThe flux-detector assembly measures 3/16-in. in OD by about 4 in. in length and is fitted with an extension so that it is movable over a 20-ft length inside a 0.210-in ID tubular well in the reactor.