Ph.D. projects

Investigations of the behavior of pressurized water reactors in case of cold water injection during the early phase of core melt scenarios

Ph.D. student:
Eduard Diaz Pescador
Dr. Frank Schäfer/Dr. Yuri Bilodid (HZDR), Prof. Dr. Uwe Hampel (HZDR, TU Dresden)
Reactor Safety


During beyond design basis accidents (BDBA) core uncover may occur and one accident management measure in the preventive domain is the injection of cold and possibly un-borated water from external sources such as fire pumps. The asymmetric injection of cold and un-borated water ensures core cooling on the one hand but simultaneously it may entail core re-criticality. The main goal of the PhD is the investigation of the injection of cold/overcooled and un-borated water in the primary side of a generic PWR KONVOI concerning multidimensional fluid mixing in the reactor pressure vessel (RPV) and core re-criticality. The research is conducted by means of the in-house nodal diffusion code DYN3D and the thermal-hydraulic system code ATHLET, both of them coupled. This approach allows to determine the core response based on the evolution of the feedback parameters against the cold water arriving to the core. The obtained results are assessed against experimental tests at the PKL and ROCOM test facilities [1] [2].


  • Investigation of three-dimensional effects in the RPV during an asymmetric injection of cold water by means of ATHLET standalone and the coupling system ATHLET-DYN3D.
  • Verification of the obtained results against experimental data.
  • Development of state-of-the-art reactor models.


  1. S. Kliem and R. Franz, "OECD PKL2 Project – Final Report on the ROCOM Tests", Institute Report HZDR\FWO\2012\03, July 2012.
  2. Rohde, U., et al., "Fluid mixing and flow distribution in the reactor circuit, measurement data base", Nuc. Eng. Des. 235 pp. 421-443, 2005.