| 摘要 |
<p>Determining the proportions of two differing fissile materials in a specimen, where the two materials have differing ratios of fission to absorption (fissile material to absorber material), consists of continuously moving the specimen along a path (call channel) in a critical reactor. At different positions along the channel the specimen causes position-dependent disturbances to the reactivity which can be calculated from the consequent change in measured power (neutron flux change with time). Initially, the dependence of the ratio of the specimen influencing functions for the two fissile materials upon the neutron spectrum existing at one position of measurement is determined and is used, in conjunction with a calibration measurement, to determine the change in the ratio of the two specimen influencing functions with the neutron spectrum at this position of measurement; then, a specimen requiring investigation is conducted through the central channel of the core and its specimen influencing function is determined at various positions of measurement having differing neutron spectrums; from this specimen influencing function, the proportions of the two types of fissile material is determined by the values obtd. from the calibration measurement. Used in particular for analysing the proportions of materials in spherical nuclear elements contg. fissile and absorber material and moderator, and more specifically, for determining the proportions of U-235 and U-233 in a fuel element.</p> |
