Current State of Fuel Performance Modelling in the Loviisa NPP
26th Symposium of AER on VVER Reactor Physics and Reactor Safety (2016, Helsinki, Finland)
Fuel behavior in normal conditions
Abstract
CURRENT STATE OF FUEL PERFORMANCE MODELLING IN THE LOVIISA NPPVille PeriFortum Power and Heat OyABSTRACTSafe operation of nuclear fuel in the Loviisa nuclear power plant is ensured not only through years of operational experience and development, but also through understanding fuel behavior in normal operating conditions, transients and accidents. In the Loviisa nuclear power plant, steady state and transient fuel behavior is currently predicted and analyzed with the TRANSURANUS fuel performance code. TRANSURANUS has been used in fuel performance calculations on Loviisa fuel rods since the year 2014. The initial analyses focused on reproducing and re-evaluating prior results from ENIGMA fuel performance calculations at Fortum and VTT, in addition to comparing the results of the TRANSURANUS calculations to data from poolside and hot cell investigations.Further and current analyses concentrate on three different subjects. Firstly, TRANSURANUS is used in justifying the safety of fuel operation in all normal operating scenarios. Even in the most limiting cases, all parameters of fuel behavior are within their respective limits. Secondly, best-estimate analyses with TRANSURANUS provide reference results for poolside investigations, where calculated fuel parameters are used in determining fission gas release ratios from gamma scanning data and as a comparison to the measured fuel properties. Thirdly, results of fuel performance analysis serve as input data for neutron-physical and process simulation codes. This paper includes a short introduction on fuel performance analyses at Fortum with a summary of the calculation process. The principles and main results of the three primary areas of analysis are reviewed. The paper is concluded with an outlook on future analyses.26th Symposium of AER on VVER Reactor Physics and Reactor Safety 52 10 – 14 October 2016, Helsinki, Finland