b'even more so, for developers of fusionneering of BEAST will be a significant reactors, especially those who haveundertaking and, once in reactor, progressed their design to the pointBEAST will continue to require of giving earnest thought to materialongoing expenditures to replace selection. In any case, the urgentbooster fuel rings and cadmium need for fast neutron irradiation databaskets as they become depleted. and the angst in obtaining it withoutThus, accelerating the realization a fast spectrum test reactor were bothof BEAST could benefit greatlyFigure 1. Illustration of the BEAST design and candidate apparent, but few are willing to statefrom collaboration and potentialflux trap locationsit so strongly since the reliable proj- cost sharing among potential users. ects are not yet underway to createAFCs support on BEAST focused on capabilities needed. These capabilityassessing conditions for fuel pins irra-needs range from monumentaldiations. The appreciable fission rates projects like the Versatile Test Reactorin the cluster of fuel pins centered or Fusion Prototypic Neutron Source,in BEAST also helped boost fast to smaller efforts such as refinedneutron population, but sometimes spectral characterization configura- irradiations are needed on structural tions for existing test reactors. materials only (such as mechanicalFigure 2. Location of Outboard-A property test specimens of claddingpositions in the SW lobeAccomplishments: alloys). As part of a collaboration AFC has been developing the Boostedwith the newly formed Innovative Energy Advanced Spectrum TestNuclear Materials initiative, assess-(BEAST) as a next generation test rigments were made to determine how for ATR which will use a flux trapbest to provide fast neutron irradia-position with a plate-type boostertions of materials only. Calculations fuel ring to multiply incidentshowed the fast neutron population thermal neutrons into fission fastin BEAST was only slightly reduced neutrons. A multi-hole cadmium- if the center test hole were filled with lined basket sits within the boostermaterial test specimens.ring to enable larger fuel rods to be tested in a more prototypic fastIn 2027, ATR will begin operating reactor spectrum. Various BEASTin a new routine where a few High configurations were analyzed, andTemperature Steady State (HTSS) recommendations provided ascycles are performed every year.Figure 3. Rendering of Cd-basket and detailed in report [1]. BEAST willThese cycles will see a ~50% increasecross sectionoffer the best possible approachin power and resulting fast flux in the to engineering scale fast spectrumoutboard A positions in the south-irradiation using existing materialwest lobe of the reactor. Not all cycles test reactors. However, detailed engi- will be at the HTSS power level, so it 2023|AFC ACCOMPLISHMENTS 211'