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Norway’s Halden reactor takes first step toward decommissioning
The government of Norway has granted the transfer of the Halden research reactor from the Institute for Energy Technology (IFE) to the state agency Norwegian Nuclear Decommissioning (NND). The 25-MWt Halden boiling water reactor operated from 1958 to 2018 and was used in the research of nuclear fuel, reactor internals, plant procedures and monitoring, and human factors.
Özlem Yilmaz, Michael Buck, Jöoerg Starflinger (Univ of Stuttgart)
Proceedings | 2018 International Congress on Advances in Nuclear Power Plants (ICAPP 2018) | Charlotte, NC, April 8-11, 2018 | Pages 900-909
In case of a severe accident in a light water reactor, core melt can be released from the reactor pressure vessel and dislocate to the reactor cavity where it attacks the concrete structures. In order to avoid possible containment failure due to molten corium concrete interaction, the molten corium is to be retained and cooled. Core-catcher concepts considering water-injection via the bottom into the melt layer can lead to rapid quenching and solidification of the melt layer, forming a highly porous structure. The COMET-PC concept relies on porous concrete layers to distribute the water below the melt layer. This paper presents investigations on hydraulics of prototypical porous concretes that have been being used for the experimental verification of the COMET-PC core-catcher system. Pressure losses within these concretes were measured for various water flow rates to determine permeability and passability of the porous concretes. Measurement results were applied in simulations of COMET-PC experiments and reactor application with the COCOMO3D code. The simulation results show that using these concretes in large reactor cavity would not provide sufficiently homogeneous cooling of the entire corium layer unless additional water distribution systems are installed.