Fast Reactors and Accelerator Driven Systems Knowledge Base

Conference Article: The control rod modelling code REGAIN

Truffert, J. (CEA Centre d'Etudes de Cadarache (France). DRN/DEC/SDC/LEMC)

Abstract

We present here the CEA’s control rod modeling code REGAIN. REGAIN is applied to modeling both normal reactor control rod operations and experimental irradiation of absorber pins. It models long permanent periods and transient pin behaviour during shutdown. Calculations are performed for a single pin with its subchannel, including the cladding, one or more different columns and possibly a shroud. The models cover both thermal, mechanical and some chemical aspects of the problem. Written in Ada language this code is built according to an object oriented method; these choices lead to high modularity, safety and portability. This architecture enables a clean division to specific modules: properties for different materials, thermal analysis, mechanical analysis and mathematical methods. Adding new materials (absorber or cladding) is possible’ either by inheritance of material properties from parent material and slight modification or in the case of very different materials (e.g. metal, ceramic, cermet and including cracks) by rewriting a specific package unit: specification and body. For boron carbide material it can deal with both sodium bonded (diving bell) and helium bonded existing design concepts. REGAIN is thus able to provide details of the absorber material and cladding temperatures, stresses and strains through the life of the rod. Absorber material is also calculated in some detail, giving porosity, 10B concentration and capture rate. REGAIN is now being licensed and will be used for the calculation of the SAC PHENIX.

view the full text of this article (7 pages, format: PDF, size= 287kB)

key words: control elements; fast reactors; neutron absorbers; r codes; shutdown; simulation; transients
Reference:
Technical committee meeting on absorber materials, control rods and designs of backup reactivity shutdown systems for breakeven cores and burner cores for reducing plutonium stockpiles. Obninsk (Russian Federation). 3-7 Jul 1995
International Atomic Energy Agency, Vienna (Austria)
IAEA-TECDOC--884, pp:53-59