b'a fast flux environment in order toAccomplishments: Figure 2. Depiction of thermal model prepare specimens for post irradiationA model of BEAST was developedand temperature estimatesexams and transient tests. in the Monte Carlo N-Particle A previous scoping study investigated(MCNP) code in the Northeast Flux use of the existing Belgium ReactorTrap (NEFT) of ATR. The model 2 (BR2) fuel assembly in an ATR fluxincorporated explicit representations trap as a fast-flux converter booster.of the BEAST booster fuel element, These results were promising, butthermal neutron filtering, and 15 it was recognized that that the BR2SFR test pin locations in the center assembly was not optimized for this(EBR-II U-10Zr fuel pins were purpose. Investigations into a newmodeled). Significant reductions in design, termed the Boosted Energythe amount of moderating coolant Advanced Spectrum Test (BEAST),water were made in the design was undertaken under AFC fundingto harden the spectrum as much in 2022. as possible. Flux levels, neutron energy spectrum, and heating rates 2022|AFC ACCOMPLISHMENTS 161'