Nuclear Engineering and Technology

Korean Nuclear Society (한국원자력학회)
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Can a nanofluid enhance the critical heat flux if the recirculating coolant contains debris?

  • Han, Jihoon (Department of Nuclear Engineering, Kyung Hee University) ;
  • Nam, Giju (Department of Nuclear Engineering, Kyung Hee University) ;
  • Kim, Hyungdae (Department of Nuclear Engineering, Kyung Hee University)
  • Received : 2021.08.12
  • Accepted : 2021.11.15
  • Published : 2022.05.25
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Abstract

In-vessel corium retention (IVR) during external reactor vessel cooling (ERVC) is a key severe accident management strategy adopted in advanced nuclear power plants. The injection of nanofluids has been regarded as a means of enhancing CHF when using the IVR-ERVC strategy to safeguard high-power nuclear reactors. However, a critical practical concern is that various types of debris flowing from the contaminant sump during operation of an ERVC system might degrade CHF enhancement by nanofluids. Our objective here was to experimentally assess the viability of nanofluid use to enhance CHF in practical ERVC contexts (e.g., when fluids contain various types of debris). The types and characteristics of debris expected during IVR-ERVC were examined. We performed pool boiling CHF experiments using nanofluids containing these types of debris. Notably, we found that debris did not cause any degradation of the CHF enhancement characteristics of nanofluids. The nanoparticles are approximately 1000-fold smaller than the debris particles; the number of nanoparticles in the same volume fraction is 1 billion-fold greater. Nanofluids increase CHF via porous deposition of nanosized particles on the boiling surface; this is not hindered by extremely large debris particles.

Keywords

Acknowledgement

This work was supported by National Research Foundation of Korea (NRF) funded by the Korean government (MSIT: Ministry of Science and ICT) (2019M2D2A1A02059364). This work was supported by the Nuclear Safety Research Program through the Korea Foundation Of Nuclear Safety (KoFONS) using the financial resource granted by the Nuclear Safety and Security Commission (NSSC) of the Republic of Korea (2106022).

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