Preliminary evaluation on the relocation phase of ex-vessel debris of fukushima daiichi nuclear power plant unit-3

Xin Li, Akifumi Yamaji, Masahiro Furuya, Ikken Sato, Hiroshi Madokoro, Yuji Ohishi

Research output: Chapter in Book/Report/Conference proceedingConference contribution


To deepen our understanding for the current debris status and investigate the debris-structure interactions in the pedestal region of Fukushima Unit-3, the Moving Particle Semi-implicit (MPS) method is further developed for simulation of multicomponent liquid/solid relocation with solid-liquid phase changes aiming for plant-scale practices. The improvement of the existing MPS method mainly consists of two parts, namely 1) the improvement of numerical stability and accuracy, including a) applying second-order corrective matrix to the particle interaction models and b) particle shifting that can optimize particle configurations; and 2) improvement of calculation efficiency, including a) hybrid OpenMP and MPI parallelization and b) particle type-dependent speed-up algorithms to reduce calculation costs for particles with extremely high viscosity and low velocity. In the current study, the improved MPS method is validated against the experiments carried out at Waseda University, in which molten salt droplets were released to interact with aluminum pillars and solidify on them. Good agreement of the total height of the solidified salt and its distribution on the pillars has been achieved. The successful validation has shown the capability of the current MPS method for simulations of Unit-3 pedestal region.

Original languageEnglish
Title of host publicationComputational Fluid Dynamics (CFD); Verification and Validation; Advanced Methods of Manufacturing (AMM) for Nuclear Reactors and Components; Decontamination, Decommissioning, and Radioactive Waste Management; Beyond Design Basis and Nuclear Safety; Risk Informed Management and Regulation
PublisherAmerican Society of Mechanical Engineers (ASME)
ISBN (Print)9784888982566
Publication statusPublished - 2021
Event2021 28th International Conference on Nuclear Engineering, ICONE 2021 - Virtual, Online
Duration: 2021 Aug 42021 Aug 6

Publication series

NameInternational Conference on Nuclear Engineering, Proceedings, ICONE


Conference2021 28th International Conference on Nuclear Engineering, ICONE 2021
CityVirtual, Online


  • Decommissioning
  • Fukushima Daiichi Nuclear Power Plant
  • MPS method
  • Severe accident

ASJC Scopus subject areas

  • Nuclear Energy and Engineering


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