A time-dependent dose model for glovebox processing of fissile material

Abstract

A new modeling system for high-intensity neutral particle radiation fields is presented. The code PANDEMONIUM calculates external effective dose rates from neutrons and photons produced at specific locations within an industrial-size plutonium processing facility. The new version of PANDEMONIUM introduces time-dependent neutronics for source multiplication coupled with transient source and detector positions. The code is designed to provide quick and acceptably accurate total effective dose estimates for scenarios and facilities for which conventional methods prove to be too impractical or costly to model. The energy range of the code has also been extended to include the effects of prompt-fission photons.

Improvement of Photon Buildup Factors for Radiological Assessment

“…The first version of Pandemonium (Photon And Neutron Dose Equivalent Model Of Nuclear Materials In Uncomplicated Geometry Models) [2] was developed by Kornreich and Dooley.…”

“…The photons that originate in an energy group remained in that group throughout the calculation and point kernel theory is applied to simulate attenuation and buildup of photons. Photon sources are determined from a library of mass-normalized photon source strengths for the various transuranic isotopes, and photon buildup factors are applied to approximate the scattered photons in the different groups [2].…”

“…The groupaveraged ENDF data that was implemented into CEPXS was outputted as a cross-section value in cm 2 , whereas the MCNPX outputted the point-wise ENDF data as its given cross section in units of barns (10 -24 cm 2 ). The comparison of the cross-section values were studied with the units of cm 2 . The equations that were used to obtain the end results are shown below: difference between the group-averaged and point-wise ENDF data is probably because of the width of the energy groups compared to a single point.…”

Improvement of Photon Buildup Factors for Radiological Assessment

“…The groupaveraged ENDF data that was implemented into CEPXS was outputted as a cross-section value in cm 2 , whereas the MCNPX outputted the point-wise ENDF data as its given cross section in units of barns (10 -24 cm 2 ). The comparison of the cross-section values were studied with the units of cm 2 . The equations that were used to obtain the end results are shown below:…”

“…This code determines the radiation dose received by workers given a set of source characteristics (nuclides, emitted radiation types and energy, material form, and density), physical distributions of sources and workers, and the shielding between them [2][3][4].…”