New sacrificial material for ex-vessel core catcher

2015 ◽  
Vol 467 ◽  
pp. 778-784 ◽  
Author(s):  
Andrei A. Komlev ◽  
Vyacheslav I. Almjashev ◽  
Sevostian V. Bechta ◽  
Vladimir B. Khabensky ◽  
Vladimir S. Granovsky ◽  
...  
Keyword(s):  
Sacrificial Material ◽  
Core Catcher

Experimental Investigation of Melt Coolability and Ablation Behavior of Oxidic Sacrificial Material at Prototypic Conditions in Scaled Down Core Catcher

2019 ◽  
Vol 5 (4) ◽  
Author(s):  
Samyak S. Munot ◽  
Ganesh V ◽  
Parimal P. Kulkarni ◽  
Arun K. Nayak
Keyword(s):  
Average Rate ◽  
Ablation Rate ◽  
Heat Temperature ◽  
Melt Pool ◽  
Simulated Experiment ◽  
Maximum Value ◽  
Sacrificial Material ◽  
Core Catcher ◽  
Core Meltdown ◽  
Time Required

To minimize the potential risk of design extension conditions (DEC) with core meltdown, some advanced reactors employ ex-vessel core catchers which stabilize and cool the corium for prolonged period by strategically flooding it. This paper describes the coolability of the melt pool and ablation process in a scaled down ex-vessel core catcher employing sacrificial material which reduces the specific volumetric heat, temperature, and density of the melt pool. To understand these phenomena, a simulated experiment was carried out. The experiment was performed by melting about 500 kg of corium simulant using thermite reaction at about 2500 °C. The bricks of oxidic sacrificial material were arranged in the core catcher vessel which was surrounded by a tank filled with water up to a certain level. After the time required for melt inversion, water was introduced to flood the test section from the top. The melt pool temperatures were monitored at various locations using “K” and “C” type thermocouples to obtain ablation depth at different elevations with time. The results show that the coolability of the molten pool in the presence of water for the present geometry is achievable with outside vessel temperatures not exceeding 100 °C. A ceramic stable crust was observed at the top surface of the melt pool, which prevented water ingression into the molten corium. The ablation rate was found to be maximum at the lower corners of the brick arrangement with the maximum value being 0.75 mm/s. An average rate of about 0.18 mm/s was obtained in the brick matrix.

scholarly journals Severe Accidents in Sodium-Cooled Fast Reactors: CFD Sensitivity Studies on the Thermal Ablation of Core-Catcher

2021 ◽  
Author(s):  
Olivier A. Czarny ◽  
Adrien Collin de l'Hortet ◽  
Nicolas Goreaud
Keyword(s):  
Thermal Ablation ◽  
Solid Material ◽  
Ablation Process ◽  
Fast Reactors ◽  
Severe Accidents ◽  
Core Catcher ◽  
Show Evidence ◽  
Internal Core ◽  
Sensitivity Studies

Abstract The present work aims at testing the CFD capabilities to simulate erosion of materials which interact with a corium mass. The main foreseen applications are the design of external/internal core catchers or in-vessel retentions devices used to mitigate severe accidents for Sodium-cooled Fast Reactors (SFR). 2D axisymmetric simulations of a corium jet impinging a sacrificial solid material show evidence of a pool-effect, previously observed in experiments, which contributes to limit the ablation process. Complementary sensitivities assess the influence of jet diameter, temperature and velocity.

Ablation of a Solid Material by High Temperature Liquid Jet Impingement: An Application to Corium Jet Impingement on a Sfr Core-Catcher

2021 ◽  
Author(s):  
Alexandre Lecoanet ◽  
Michel Gradeck ◽  
Xiaoyang Gaus-Liu ◽  
Thomas Cron ◽  
Beatrix Fluhrer ◽  
...  
Keyword(s):  
High Temperature ◽  
Deep Understanding ◽  
Jet Impingement ◽  
Severe Accident ◽  
Mitigation Measures ◽  
Liquid Jet ◽  
Cavity Formation ◽  
The Core ◽  
Core Catcher ◽  
Temperature Liquid

Abstract This paper deals with ablation of a solid by a high temperature liquid jet. This phenomenon is a key issue to maintain the vessel integrity during the course of a nuclear reactor severe accident with melting of the core. Depending on the course of such an accident, high temperature corium jets might impinge and ablate the vessel material leading to its potential failure. Since Fukushima Daiichi accident, new mitigation measures are under study. As a designed safety feature of a future European SFR, bearing the purpose of quickly draining of the corium out of the core and protecting the reactor vessel against the attack of molten melt, the in-core corium is relocated via discharge tubes to an in-vessel core-catcher has been planned. The core-catcher design to withstand corium jet impingement demands the knowledge of very complex phenomena such as the dynamics of cavity formation and associated heat transfers. Even studied in the past, no complete data are available concerning the variation of jet parameters and solid structure materials. For a deep understanding of this phenomenon, new tests have been performed using both simulant and prototypical jet and core catcher materials. Part of these tests have been done at University of Lorraine using hot liquid water impinging on transparent ice block allowing for the visualizations of the cavity formation. Other tests have been performed in Karlsruhe Institute of Technology using liquid steel impinging on steel block.

scholarly journals Highly porous multiwalled carbon nanotube buckypaper using electrospun polyacrylonitrile nanofiber as a sacrificial material

Heliyon ◽  
2019 ◽  
Vol 5 (3) ◽  
pp. e01386 ◽  
Author(s):  
J.A. Rojas ◽  
L.A. Ardila-Rodríguez ◽  
M.F. Diniz ◽  
M. Gonçalves ◽  
B. Ribeiro ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Multiwalled Carbon Nanotube ◽  
Multiwalled Carbon ◽  
Sacrificial Material ◽  
Highly Porous

Numerical Investigation of Heat Transfer Characteristics of Debris Bed After Severe Accident of SFR Based on 1-D Heat Conduction Model

2018 ◽  
Author(s):  
Mengwei Zhang ◽  
Bin Zhang ◽  
Jianqiang Shan
Keyword(s):  
Heat Transfer ◽  
Heat Conduction ◽  
Transfer Process ◽  
Severe Accident ◽  
Heat Transfer Characteristics ◽  
Conduction Model ◽  
One Dimensional ◽  
The Core ◽  
Transfer Characteristics ◽  
Core Catcher

Nuclear reactor severe accidents can lead to the release of a large amount of radioactive material and cause immense disaster to the environment. Since the Fukushima nuclear accident in Japan, the severe accident research has drawn worldwide attention. Based on the one-dimensional heat conduction model, a DEBRIS-HT program for analyzing the heat transfer characteristics of a debris bed after a severe accident of a sodium-cooled fast reactor was developed. The basic idea of the DEBRIS-HT program is to simplify the complex energy transfer process in the debris bed to a simple one-dimensional heat transfer problem by solving the equivalent thermal conductivity in different situations. In this paper, the DEBRIS-HT program code is prepared by using the existing model and compared with the experimental results. The results show that the DEBRIS-HT program can correctly predict the heat transfer process in the fragment bed. In addition, the heat transfer characteristics analysis program is also used to model the core catcher of the China fast reactor. Firstly, the dryout heat flux when all of molten core dropped on the core catcher was calculated, which was compared with the result of Lipinski’s zero dimensional model, and the error between two values is only 11.2%. Then, the temperature distribution was calculated with the heat power of 15MW.

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