Contact

Ronald Oertel
Computational Fluid Dynamics
r.oertelAthzdr.de
Phone: +49 351 260 - 3157

Dr. Eckhard Krepper
Computational Fluid Dynamics
e.krepperAthzdr.de
Phone: +49 351 260 - 2067
Fax: +49 351 260 - 12067

Dr. Dirk Lucas
Head Computational Fluid Dynamics
d.lucasAthzdr.de
Phone: +49 351 260 - 2047
Fax: +49 351 260 - 12047

Safety of storage pools for spent nuclear fuel (SINABEL)

The collaborative project "SINABEL", funded by the Federal Ministry of Education and Research (BMBF) in the framework of the R&D program "Grundlagenforschung Energie 2020+" and accomplished by Helmholtz-Zentrum Dresden-Rossendorf (HZDR), the Technische Universität Dresden (TUD) and the University of Applied Sciences in Zittau/Görlitz (HSZG) is directed on the examination of the safety of storage pools for spent nuclear fuel. With the accident at the nuclear power plant Fukushima Daiichi in March 2011, the subject moved into the focus of nuclear safety research. After the removal of a fuel assembly from the reactor pressure vessel, it is stored in a water-filled pool over several years, in order to remove the heat that is created by nuclear decay. The nuclear decay heat production of an assembly decreases exponentially after its removal from the reactor core. Typical values lie between 200W per fuel rod at three days following removal, down to 5W after two years. Accordingly, the decay heat power of the individual fuel assembly is relatively small. A fully loaded pool exhibits a power of several megawatts however. A failure of the pool cooling system, for example due to a malfunction of the power supply of the plant, can result in a partial uncovering of the fuel elements. Within the HZDR part of the project, numerical flow simulation is applied to detect possible problems of the coolability of the fuel assemblies. The focus lies with the flow in the pool atmosphere for partially uncovered fuel assemblies. The connection between the spatial distribution of the decay heat in the pool and the large scale flow phenomena is examined. Problematic storage configurations of the fuel assemblies in the storage racks are determined as well as the feedback onto the flow in the single assembly. Current results show, that the large scale flow is relatively independent on the decay heat distribution in the storage pool (see Figure 1 and 2). The geometry-resolving simulations of the project partner TUD-ISM show a convective exchange of heat between the atmosphere and the interior of the fuel assembly also for high-density storage. The intensity of the exchange depends on its location in the pool. Thereby, the long-range order of the fuel assemblies as well as their short-range order has an influence on the coolability. As a result of the work, recommendations for favorable storage constellations will be published.

Temperaturverteilung und horizontale Geschwindigkeitskomponente auf der Brennelementkopf-Ebene für unterschiedliche Anordnungen.
Abb. 1: Temperaturverteilung und horizontale Geschwindigkeitskomponente auf der Brennelementkopf-Ebene für unterschiedliche Anordnungen.
Vertikale Geschwindigkeitskomponente auf halber Beckenhöhe für unterschiedliche Anordnungen.
Abb. 2: Vertikale Geschwindigkeitskomponente auf halber Beckenhöhe für unterschiedliche Anordnungen.

Acknowledgement

This work is carried out in the frame of a current research project funded by the German Federal Ministry of Education and Research, project number 02NUK027C.

BMBF-Sponsoring


Publications

R. Oertel, E. Krepper, D. Lucas
CFD Simulation of Spent Fuel Pool Accidents resulting in partially uncovered Fuel Assemblies
47th Annual Meeting on Nuclear Technology (AMNT 2016), 10.-12.05.2016, Hamburg, Deutschland

R. Oertel, E. Krepper, D. Lucas
Application of CFD towards the thermo-hydraulic analysis of Spent Fuel Pool accidents
16th International Topical Meeting on Nuclear Reactor Thermalhydraulics(NURETH-16), 30.09.-04.10.2015, Chicago, USA

R. Oertel, E. Krepper, D. Lucas
Large Scale CFD Simulations of Spent Fuel Pool Accident Scenarios Using a Porous Body Approach
46th Annual Meeting on Nuclear Technology (AMNT 2015), 05.-07.05.2015, Berlin, Deutschland


Contact

Ronald Oertel
Computational Fluid Dynamics
r.oertelAthzdr.de
Phone: +49 351 260 - 3157

Dr. Eckhard Krepper
Computational Fluid Dynamics
e.krepperAthzdr.de
Phone: +49 351 260 - 2067
Fax: +49 351 260 - 12067

Dr. Dirk Lucas
Head Computational Fluid Dynamics
d.lucasAthzdr.de
Phone: +49 351 260 - 2047
Fax: +49 351 260 - 12047