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2 results on '"melt pouring"'

1. Three-dimensional numerical study on the effect of sidewall crust thermal resistance on transient MCCI by improved MPS method.

Author

Cai, Qinghang, Zhu, Dahuan, Chen, Ronghua, Deng, Jian, Li, Yonglin, Dong, Chunhui, Tian, Wenxi, Qiu, Suizheng, and Su, G.H.

Subjects
*THERMAL resistance, *NUCLEAR power plants, *NUCLEAR power plant accidents, *PRESSURE vessels, *HEAT transfer
Abstract

• 3-D simulation of a MCCI test was presented with improved MPS method. • Three crust heat transfer models or assumptions were applied to explore the effect of crust thermal resistance on MCCI. • Difference ablation patterns were obtained due to the lower melt pouring rate. Molten Corium and Concrete Interaction (MCCI) is the phenomenon that could occur in the severe accident of nuclear power plant (NPP) after the failure of reactor pressure vessel (RPV). There are considerable uncertainties regarding the MCCI initial conditions, including melt pouring, which is harder to be considered in many severe accident analysis codes. In this study, the improved MPS method with explicit pressure method was used to simulate the pouring stage of HECLA-3 transient MCCI experiment. The anisotropic ablation was obtained at a lower pouring rate, which was in good agreement with the experiment. It is found that the initial sidewall crust formation is the main reason for the ablation difference of MCCI caused by low melt pouring rate. And the mechanism of adiabatic effect of the crust layer on MCCI was revealed by the comparison of simulation results with three different crust heat transfer models or assumptions. [ABSTRACT FROM AUTHOR]

Published
2020
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2. Development of Scaling Approach for Prediction of Terminal Spread Thickness of Melt Poured into a Pool of Water

Author

Konovalenko, Alexander and Kudinov, Pavel

Subjects
melt pouring, Other Physics Topics, scaling, pulims, Annan fysik, corium, uncertainty, sensitivity, spreading model
Abstract

Corium melt stabilization and long term cooling in a pool of water located beneath reactor vessel is adopted in several existing designs of light water reactors (LWRs) as an element in severe accident (SA) mitigation strategy. At certain conditions of melt release into the pool (e.g. large ratio of the vessel breach size to the pool depth), liquid melt can spread under water and reach a coolable configuration. Coolability of the melt is contingent on terminal spread thickness of the melt layer \delta_{sp} which defines decay heat generated per unit area of the melt surface. The thickness of the melt layer is determined by the competition between characteristic time scales of hydrodynamic melt spreading and solidification of the melt. This paper presents a modification of the scaling approach, originally proposed by Dinh et al. (2000) for prediction of the terminal melt spread thickness, to the case when liquid melt jet is poured into a pool of water and allow to spread unrestricted on a horizontal floor of the pool. Modified scaling approach takes into account mass and heat losses during to melt jet interaction with the coolant. The hydrodynamic spreading timescale is described with phenomenological approaches proposed by Huppert and Britter (1982) and Britter (1979). Proposed model is validated against PULiMS experiments (Pouring and Underwater Liquid Melt Spreading Konovalenko et al., 2012). Finally, sensitivity analysis and preliminary assessments of the uncertainties are performed for the PULiMS test conditions. BEST PAPER AWARD!QC 20131216

Published
2012

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