LOWERING ENGINEERING FACTOR FOR DNBR MARGIN FOR FUEL ASSEMBLIES TVS-2M AND TVSA
23rd Symposium of AER on VVER Reactor Physics and Reactor Safety (2013, Štrbské Pleso, Slovakia)
Reactor dynamics and safety analysis
In the paper is represented the robust method of calculation of reducing engineering
factor for DNBR, which can be used in ?hot channel? model in nuclear reactor safety analysis.
The estimation of DNBR producing with help of method of statistical account of
uncertainties. The method is based on the special developed FA model which includes
mathematical models of energy field calculations, FA thermomechanical deformations,
thermohydraulics and technological processes. FA thermohydraulics calculations carry out
using cell by cell thermohydraulic code SC-1 1. In these calculations were taken into
account deviations in different parameters.
Due to construction distinctions of different type cassettes the values of DNBR and
engineering coefficients in these cassettes can be vastly different. In the paper is shown
comparison of DNBR values and reducing engineering factors for DNBR in TVS-2M and
TVSA. The sensitivity of reducing engineering factor for DNBR was analyzed for different
factors: changing of power level, relative axial heat flux profiles, rods energy distribution, the
law of statistical distribution random parameters, deformation of energy field.
The researching of stability minimal DNBR values localization in normal and
emergency processes was done.