VTT's APROS software is renewed to simulate nuclear power plants of the future

According to the main designer of the APROS software, Dr Kaj Juslin, Chief Research Scientist at VTT, it is developed to suite analysis needs of evolving new types of power plants such as Gen4 nuclear power plants and clean combustion power plants.

APROS version 5.08 brings several new features for the end-users. APROS steam tables have been extended to the supercritical region of interest in the design of new and more efficient power plants. Provisions are made for calculation of typical Gen4 coolants such as helium, sodium, lead and salts. Material properties for hydrogen and hydrocarbons, for example, are available for calculation of reactions and flows in synthetic fuel production processes.

APROS provides for elementary model building blocks enabling the user to graphically specify more extensive process component models in detail. Elementary blocks for the calculation of heat accumulation and diffusion in structures cover both plate, cylindrical, and spherical geometries. Model specifications can be written to ASCII-files using the versatile model specification language of APROS and easily transported to new software versions, computer hardware or operation systems. The specification language enables interconnection of APROS to other design tools and especially to new semantic design databases of both processes and control systems.

APROS simulation software is used in 20 countries. In Finland, it has been exploited in independent analysis calculations of the EPR plant under construction in Olkiluoto and in designing new digital automation systems for the Loviisa VVER plants. Other full-scope ARPOS-based simulators have been developed to replicate nuclear power plants of Russian, Swedish and Chinese design. As well as a design tool for prominent contractors and engineering agencies, APROS is used in training on how the processes operate.

APROS is the result of two decades of continuous and dedicated developments by VTT experts in co-operation with the Finnish energy company Fortum. The quality of each new version is thoroughly verified and validated. Along the way, end users have given valuable feedback and new goals to the developers. Now, for instance, the need for calculations that are hundreds of times faster than real-time in predicting simulators has been made clear to developers.