Materials are evaluated for use as in-core diluents and as peripheral reflectors for Gas-Cooled Fast Reactor (GFR) service, using coupled Monte Carlo (MCNP) and isotopics (ORIGEN) codes. The principal performance indices compared were effects on beginning of irradiation multiplication factor, reactivity-lineated burnup, and coolant (here CO2) void reactivity. While low values of the macroscopic...

In CANDU reactors, shim operation is used when the online refuelling capability becomes temporarily unavailable. Adjuster rods, normally in-core to provide flux flattening, are withdrawn in sequence additional reactivity as fuel depleted. a 900 reactor, up three of eight adjuster banks may be withdrawn, with power derated accordingly. this study, was modelled using combination TRACE_Mac1.1, PAR...

In the Theory of Challenge and Threat States in Athletes (TCTSA) it is proposed that on approach to motivated performance situations an individual can respond in a challenge state or a threat state. Challenge and threat states are marked by contrasting patterns of psychological, emotional, and cardiovascular (CV) responses. A challenge state is proposed to maintain or facilitate performance com...

This article gives an overview of recently published literature on the factors that govern SN2 reactivity. By comparing reactivity in solution with that in the isolated gas phase, it has become possible to dissect the contribution of the solvent from that of the intrinsic molecular properties. This has proven to be an extremely important and fruitful step forward in obtaining key knowledge not ...