Quantitative safety analysis of cryogenic liquid releases in a deep underground large scale installation

The present work considers the quantitative risk assessment of a heat insulated Tank designed to host over 65 kt of cryogenic argon. A specially built detector grid will be submerged in the cryogenic medium to allow the detection of subatomic particles (neutrinos). The Tank and associated equipment for cooling, heating, pressurization and filtration, are located in appropriately constructed caverns 1400 m underground. Previous work on this infrastructure focused on pressure control failures leading eventually to minor argon gas leaks (Marcoulaki et al., 2016 [7]). This work identifies possible initiators for direct loss of containment and release of liquid argon in the underground premises, discusses the proposed safety measures, and presents results for two release category types involving medium and major liquid argon spills. Assessment of consequences aims at identifying the risks of human casualties and/or collapse of the underground caverns. Detailed thermodynamic predictions and CFD dispersion simulations are performed to support the phenomenology analysis.