An experimental device for studying the migration behavior of melt in the channel of lead-based reactor rods

Abstract

The invention discloses an experiment device for studying migration behaviors of a melt in a rod bundle channel of a lead-based reactor. Seven rods in the device are arranged in a regular triangle shape; a fuel rod in the right center is composed of a stainless steel shell and tungsten-rhenium heating rod; six rods around are non-heating stainless steel rods; the seven rods are arranged inside a lead bismuth alloy coolant channel; electric heating is carried out through the tungsten-rhenium heating rod in the center, decay heat of the fuel rods is simulated, and then the stainless steel shellis heated and molten. Through a reasonably arranged high temperature resistant tungsten-rhenium thermocouple, transient temperature parameters of the rods, the melt and a lead bismuth alloy coolant are measured, and due to adoption of a high-speed camera and a fluoroscopy device, a dynamic expansion process of a stainless steel shell melt after being migrated to a lead bismuth alloy coolant liquidlevel is recorded; distribution and morphology of a stainless steel melt inside a component after an experiment are studied, and then a fuel element melting process and a flowing expansion behavior of the melt in a rod bundle channel are analyzed; by adopting the experiment device, a significant experiment device is provided to study migration of a melt in a rod bundle channel and reposition themelt in a reactor core melting process in case of a serious lead-based reactor accident.

Description

technical field [0001] The invention relates to the technical field of research on the migration and relocation characteristics of molten matter between rod bundle channels during a severe accident of a lead-based reactor, in particular to an experimental device for studying the migration behavior of molten matter in the rod bundle channels of a lead-based reactor. Background technique [0002] As the fourth-generation nuclear energy system, the safety and reliability of lead-based reactors, especially the response capability under severe accidents, have received extensive attention; although lead-based reactors have relatively high safety, their unprotected transient Under the triggering of initiating events such as unprotected undercooling, there may still be serious accidents in which large-area fuel elements fail to melt, and after the fuel elements fail, there is theoretically fuel accumulation during the migration of fuel particles in the stack that leads to The possib...

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Problems solved by technology

[0002] As the fourth-generation nuclear energy system, the safety and reliability of lead-based reactors, especially the response capability under severe accidents, have received extensive attention; although lead-based reactors have relatively high safety, their unprotected transient Under the triggering of initiating events such as unprotected undercooling, there may still be serious accidents in which large-area fuel elements fail to melt, and after the fuel elements fail, there is theoretically fuel accumulation during the migration of fuel particles in the stack that leads to The possibility of the reactor returning to criticality, the serious consequence of which is a sudden increase in reactor power, which may eventually lead to the occurrence of a core disintegration accident, causing a large-scale release of radioactive materials;

[0003] Core material melting, melt migration, solidification and relocation phenomena play a crucial role in the recritical risk of lead-based reactors, and its mechanism research has always been one of the hotspots and difficulties in the research of lead-based reactors; due to lead-based materials The boiling point of the coolant is higher than the melting point of the cladding, and the melting, migration and re-solidification process of the core material of the lead-based reactor is obviously different from the relevant process under the serious accident of the pressurized water reactor and the sodium-cooled fast reactor; although a large number of core materials have been made internationally Experiments on migration and resolidification, but public and complete experimental data are very scarce

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