Sodium-cooled fast reactor debris bed migration criterion method

Abstract

The invention discloses a sodium-cooled fast reactor debris bed migration criterion method which comprises the following steps: carrying out stress analysis on debris particles in a debris bed by combining the density, size, shape and position of the particles, and meanwhile, introducing a liquid bridge force resultant force for representing a liquid surface tension effect to obtain a stress balance equation in a critical state in a migration process; the relative speed between the fragment particles under the liquid surface tension effect and the fluid is obtained, the external fluid speed is considered, the relative speed between the fragment particles under the liquid surface tension effect and the fluid is compared with the external fluid speed, and whether the fragment bed migrates or not is judged. According to the method, the movement trend of the fragment bed in the migration process can be correctly predicted, the migration characteristics of the fragment bed in the lower cavity in the sodium-cooled fast reactor core disintegration accident are effectively evaluated, and the problems that the migration phenomenon simulation effect of the fragment bed is poor and the credibility is not high in the prior art are solved.

Description

technical field [0001] The invention belongs to the technical field of nuclear reactor safety facility design, and in particular relates to a method for migration criterion of a sodium-cooled fast reactor debris bed. Background technique [0002] In the core disintegration accident of a sodium-cooled fast reactor, the molten core fuel will diffuse to the lower chamber of the core, on the one hand, it will be quenched, solidified and dispersed into fragmented particles by the action of the coolant in the lower chamber; On the one hand, the particles of the debris bed are subjected to gravity, and accumulate into a mound-like debris bed on the surface of the core melting collector in the lower chamber of the core. Due to the decay heat of the fuel particles, the coolant in the debris bed will boil, and the debris particles will migrate under the combined promotion of sodium vapor and liquid sodium, which will change the overall shape and thickness of the debris bed, and "migra...

AI Technical Summary

Problems solved by technology

The current semi-empirical migration criterion method for simulating the migration behavior of debris beds still has many shortcomings, the simulation effect is poor, and the reliability is not high

Images