Comparison of Experimentally Measured and Calculated Radiation Environment Internal to the PAX R-1 Reactor

Radiation data calculated by the discrete-ordinates technique is compared with experimentally determined information measured on the PAX intermediate spectrum reactor which is neu-tronically similar to the NERVA nuclear rocket. The information compared consists of the neutron dose rate, photon dose rate, fast neutron flux (measured with ²³⁸ U and sulfur detectors), and thermal neutron flux (measured with bare- and cadmium-covered dysprosium detectors) data in the core and reflector of the reactor. The calculated results displayed the same shape as the experimental data for all detectors and, with the exception of the bare dysprosium data in the core and the sulfur data, the calculated results had the same magnitude as the experimental results within the limits of experimental accuracies.