[3K01-09] 1F Accident 2

[3K08] Estimation of RPV damage and fuel debris relocation behavior in the PCV at Fukushima Daiichi Nuclear Power Station

(8)Numerical simulation of core material relocation behavior in the RPV lower head region

*Xin Li¹, Akifumi Yamaji², Ikken Sato², Takuya Yamashita¹ (1. JAEA, 2. Waseda Univ.)

Keywords:Fukushima Daiichi Nuclear Power Station (1F), MPS method, Severe accident analysis

This study presents a numerical evaluation of possible core material discharge behavior from the RPV lower head region including the penetrations (Control Rod Drive (CRD) Housing) in 1F Unit-2 with Lagrangian-based MPS method. Two-dimensional geometry is established to model CRD housing with simplified inner structures in the center of RPV, with surrounding RPV walls and RPV insulation below. The initial temperature distribution/boundary conditions referenced the results from accident progression and global RPV CFD analysis (Series presentations (2), (5), and (7)). The results show that local CRD housing melting assumed at 15%Zr-85%Fe eutectic temperature (1523 K) before global RPV failure could result in melt discharge into the pedestal, which is consistent with the accident progression analysis and plant internal investigation results.