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Annual Report

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To optimize the performance of accelerator driven transmutation systems (ADS), engineers will need to design the system to operate with a neutron multiplication factor just below that of a critical, or self-sustaining, system. This design criteria requires particle transport codes that instill the highest level of confidence with minimal uncertainty, because the larger the uncertainties in the codes, the larger the safety margin required in the design and the lower the efficiency of the ADS transmuter. For current design efforts, the MCNPX code is used to determine neutron production and transport for spallation neutron systems.

While providing a very useful research and modeling tool, the uncertainties in MCNPX, particularly at higher energies, require engineers to increase the safety margin in the designs of the ADS transmuter. Much of the uncertainty associated with MCNPX is thought to be due to the escape of multiple high energy particles from the target (multiple scattering), along with uncertainties in the predictions of source term volume measurements. Determining a reliable method that measures, validates, and benchmarks the code calculations of such a volume source term is necessary.

The primary goal of this research is to develop and deploy the detector systems necessary for the measurement of neutron leakage from targets in calibrated beam lines, and to produce precise, position sensitive measurements of the source term volume for neutron production.


Accelerator-driven systems – Design and construction; Radioactive wastes — Transmutation


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