LWR neutronics thermal-hydraulics code for scoping applications

A methodology combining basic neutronics and thermal-hydraulics models has been formulated in a computer program, designated NTHAD (Neutronic and Thermal-Hydraulic Assembly Design). It has been programmed in BASIC for use on widely available microcomputers to permit rapid parameter studies of the burnup physics and fluid flow/heat transfer properties of light water reactor (LWR) fuel assemblies. The most significant research application to date has been in evaluation of various mechanical spectral shift concepts for pressurized water reactor (PWR) control. It has been found that the NTHAD program, because of its all-in-one nature and its extreme flexibility is a useful tool for scoping studies on advanced LWR core design and control concepts. Furthermore, its modular nature and the use of an assemblage of submodels which are no more complex than required for a given task, make it particularly useful for studying the physical phenomena involved and the rapid execution of parametric studies involving both design characteristics and model sophistication