Calculation of the HPRR Neutron Spectrum for Simulated Nuclear Accident Conditions

Abstract

Since 1964, the Health Physics Research Reactor (HPRR) at the Oak Ridge National Laboratory has been used to simulate nuclear excursions to allow intercomparisons of accident dosimetry systems. Generally, activation foils or threshold-activation foils are used to measure the neutron fluence. Usually, data from these detectors are used to provide the neutron dose and the general shape of the neutron energy spectrum. However, some participants have used an iterative technique to calculate a spectral distribution to fit the experimental results. A calculational study was begun to provide the HPRR neutron spectrum for three typical accident exposure conditions. Results of these calculations are compared with spectra derived from the use of several dosimeters under actual exposure conditions at the HPRR. Also included in the results of the calculation were neutron dose distributions as a function of distance from the reactor. These results are compared with the results of measurements performed during the Intercomparison Study of 1971.

Sulfur Pellets Responses to a Bare and Steel Reflected Pulse of the Oak Ridge National Laboratory Health Physics Research Reactor

“…The superstructure is the name given to all the other components located above the core related to the its operation, like rod drives, starting source, and detectors. No drawing with dimensions of the superstructure elements was found, but schematics of an old calculation model from 1974 [11] is shown in Figure 25, and an overview drawing of the HPRR with the superstructure attached is shown in Figure 26. From those pictures, a few assumptions can be made.…”