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Conclusion
Published in David Toke, Geoffrey Chun-Fung Chen, Antony Froggatt, Richard Connolly, Nuclear Power in Stagnation, 2021
David Toke, Geoffrey Chun-Fung Chen, Antony Froggatt, Richard Connolly
Various safety measures and practices have been selected for inclusion in these tables on the basis that they are, in a review of the relevant literatures, ones that feature prominently in discussions and technical reports about safety. There is discussion of these measures in the different chapters, but, we can add here in order to explain the acronyms that a) FCVS stands for ‘filtered containment venting system’. This type of system attempts to ensure that in the event of a severe accident, pressure within the containment vessel can be reduced by venting gases whilst filtering out the radioactivity that would remain within the plant itself. b) PAR stands for ‘Passive Autocatalytic Recombiner’ which, in the event of a severe accident, attempts to safely ‘recombine’ hydrogen inside the reactor building that might otherwise explode. c) Independent power generation (and water supply) means that in the event of a severe accident the reactor can continue to be cooled, and therefore the possibilities of radioactive releases and meltdown reduced. Other measures are self-explanatory.
Evaluation of the PAR Mitigation System in Swiss PWR Containment Using the GOTHIC Code
Published in Nuclear Technology, 2019
Davide Papini, Michele Andreani, Pascal Steiner, Bojan Ničeno, Jens-Uwe Klügel, Horst-Michael Prasser
Passive autocatalytic recombiners (PARs) are an established safety measure to mitigate the possible hydrogen risk during beyond-design-basis and severe accidents in nuclear reactor containment, particularly during accidents with loss of off-site power. The PARs are self-starting, due to the buoyant flow induced by the heat released from the exothermic recombination reaction of hydrogen and oxygen into steam, which makes a PAR a completely passive operating device. The hydrogen and the oxygen (from the air) react (i.e., recombine) at the catalyst surface to form water vapor and heat. The catalyst (e.g., platinum) promotes the reaction by lowering the threshold so that the reaction takes place at a low temperature and concentration. The balanced recombination reaction reads