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Published on: December 14, 2017
Analysis of neutron emissions from pebble nuclear fuels
Holden Walker1, Braden Goddard1
1Department of Mechanical and Nuclear Engineering, Virginia Commonwealth University, 401 West Main Street, Richmond, VA, 23284, USA.
None:
This work discusses the development of a tool for the instant modeling and analysis of neutron emissions for a single pebble nuclear fuel removed from the core of a Pebble Bed Reactor (PBR). The creation of this tool utilized computer codes SOURCES-4C and MCNP6.3 to generate data for converting any pebble's actinide masses into an energy-dependent neutron emission rate. This modeling method tackled unique challenges, primarily due to the small geometry of the TRi-structural ISOtropic (TRISO) particles within the fuel. The generated tool is capable of producing an energy-dependent neutron emission spectra for an entire pebble, or from the individual contribution of actinides within a pebble. Using the tool, estimations of a pebble that underwent 1304 days of burn time resulted in a total of 56,799 neutrons per second. Based on a plot of neutron emission over pebble burnup time generated by this tool, neutron detection in PBRs can be used to evaluate pebble cycling decisions for online refueling methods. Additionally, the ability to provide individual actinide neutron emission from pebbles aids waste management decisions for classifying the waste, as well as considering safety concerns in accident analyses.
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