Physical-chemical Background of the Potential Phase Transitions during Loss of Coolant Accidents in the Supercritical Water Loops of Various Generation IV Nuclear Reactor Types

Authors

  • Gábor Györke
    Affiliation

    Department of Energy Engineering, Faculty of Mechanical Engineering, Budapest University of Technology and Economics, H-1111 Budapest, Műegyetem rkp. 3, Hungary

  • Attila R. Imre
    Affiliation

    Thermohydraulics Department, Atomic Energy Research, Centre for Energy Research, Hungarian Academy of Sciences (MTA), H-1525 Budapest, POB 49, Hungary

https://doi.org/10.3311/PPch.12770

Abstract

Loss of coolant accidents (LOCA) are a serious type of accidents for nuclear reactors, when the integrity of the liquid-loop breaks. While in traditional pressurized water reactors, pressure drop can cause flash boiling, in Supercritical-Water Cooled reactors, the pressure drop can be terminated by processes with fast phase transition (flash boiling or steam collapse) causing pressure surge or the expansion can go smoothly to the dry steam region. Modelling the pressure drop of big and small LOCAs as isentropic and isenthalpic processes and replacing the existing reactor designs with a simplified supercritical loop, limiting temperatures for various outcomes will be given for 24.5 and 25 MPa initial pressure. Using the proposed method, similar accidents for chemical reactors and other equipment using supercritical fluids can be also analyzed, using only physical-chemical properties of the given supercritical fluid.

Keywords:

adiabatic expansion, isenthalpic expansion, steam collapse, flash boiling

Published Online

2019-03-18

How to Cite

Györke, G., Imre, A. R. “Physical-chemical Background of the Potential Phase Transitions during Loss of Coolant Accidents in the Supercritical Water Loops of Various Generation IV Nuclear Reactor Types”, Periodica Polytechnica Chemical Engineering, 63(2), pp. 333–339, 2019. https://doi.org/10.3311/PPch.12770

Issue

Section

Articles