Nanofluid applications in Nuclear Reactor Severe Accident Mitigation

L-W Hu
Massachusetts Institute of Technology, US

Keywords: nanofluid, CHF enhancement, IVR

Summary:

Nanofluids have been shown experimentally to increase of critical heat flux (CHF) compared to water at low concentrations (<0.1% by volume). The use of nanofluids in severe accident management would allow either to increase the safety margins in case of a severe accident or to upgrade the power of an existing power plant with constant margins. A potential nanofluids application in nuclear systems was evaluated for In-vessel retention (IVR) with enhanced boiling heat transfer of reactor vessel using a nanofluid injection system. The nanofluid injection system and natural convection in reactor cavity were analyzed to verify the mixing capabilities of a conceptual nanofluid injection system. Experimental results for flow boiling using stainless steel heaters showed that dilute water-based alumina nanoparticles (0.001% by volume) yielded an average 70% CHF enhancement with range of 17% to 108% depending on the specific flow conditions expected for IVR. Experiments also indicate that only about thirty minutes of boiling time (which drives nanoparticle deposition) is needed to obtain substantial flow boiling CHF enhancement with nanofluids.