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This chapter provides a discussion of radiation safety aspects of operation of electron linear accelerators equipped with bremsstrahlung converters. Electron accelerators with 3, 6, 9 and 15 MeV electron beams are discussed. High-energy photon and photoneutron production during linac operation was analyzed using Monte Carlo methods. Radiation dose rates for diferent conigurations of linacs were evaluated and compared with experimental results.

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Abstract.A Varian K15 electron linear accelerator (linac) has been considered for installation at University of Nevada, Las Vegas (UNLV). Before experiments can be performed, it is necessary to evaluate the photon and neutron spectra as generated by the linac, as well as the resulting dose rates within the accelerator facility. A computational study using MCNPX was performed to characterize the source terms for the bremsstrahlung converter. The 15 MeV electron beam available in the linac is above the photoneutron threshold energy for several materials in the linac assembly, and as a result, neutrons must be accounted for. The angular and energy distributions for bremsstrahlung flux generated by the interaction of the 15 MeV electron beam with the linac target were determined. This source term was used in conjunction with the K15 collimators to determine the dose rates within the facility.

The mission of the Transmutation Research Program (TRP) at University of Nevada, Las Vegas (UNLV) is to establish a nuclear engineering test bed that can carry out effective transmutation and advanced reactor research and development effort. UNLV has developed a multi-function software package, TRPSEMPro, to interact with the chemical separation process developed by the Argonne National Laboratories (ANL). As indicated in the Spent Fuel Treatment Facility (SFTF) process requirement, developing a software package system with the capability of optimizing facility process based on the pre-defined objective functions can be valuable for the SFTF. The objective is to further extent the TRPSEMPro framework to integrate chemical separation calculation package AMUSE (Argonne Model for Universal Solvent Extraction) with commercially available system process package (ASPEN-plus). A development concept of middleware is employed to build communication between the AMUSE code and the ASPEN-plus. Since the object-oriented designed ASPEN-plus software package exposes its parameters as well-defined objects, the TRPSEMPro can directly access its variable trees through the object call. Due to the complicity of the system, a scenario-based database system will be developed associated with the chemical separation and system processes. A light-weight MS ACCESS database is selected for easy maintenance and accessibility. The database manages the scenario parameter files with associated separation results and outputs from the system process packages. A comprehensive SFTF process simulation will greatly facilitate the evaluation of overall systems options. Such simulation is gradually becoming important for down-selecting reactor types, fuel types, and multi-recycle modes. Optimization tool associated with the TRPSEMPro system engineering model intends to speedup the possible chemical separation parameters.