Dr. Frank Bok
Surface Processes
Phone: +49 351 260 2076

PhD thesis

Development of transport solutions for zooming in DYN3D

PhD student:
Dzianis Litskevich
Dr. Bruno Merk (HZDR)
Reactor Safety


Nowadays the reactor dynamics code DYN3D widely used for the analysis of a broad spectrum of transients in Light Water Reactors. DYN3D is available in two versions - for Russian VVER type reactors and western LWRs. DYN3D is nodal code and uses for calculations multigroup diffusion approximation. For solving diffusion equations it uses homogenized cross-sections inside each assembly. It means that power distribution calculates for each assembly inside the core separately.

For safety calculations we need not only power distribution in the core on the assembly level, but also pin-power distribution inside assemblies to determine, for example, hot channels. In this case diffusion approximation is not enough and we have to use higher order of approximation like transport solutions.


The aim of this study is to develop transport solution for pin-power reconstruction (zooming) inside assembly using information obtained from diffusion calculations in DYN3D.


Dzianis Litskevich
Reactor Safety