Pressure vessel and method for simulating upper chamber droplet entrainment of nuclear reactor

Abstract

The invention discloses a pressure vessel and a method for simulating upper chamber droplet entrainment of nuclear reactor. The pressure vessel is mainly composed of a water inlet, a gas inlet, a heating area, an experimental area and an air water outlet. The pressure vessel can carry out experiments in two working media, air-water and steam-water, can use heating rods to simulate core decay heat and realize physical simulation of the upper chamber entrainment phenomenon; and reactor internals and core upper plate contained in the pressure vessel can realize real reflection of simulation of upper chamber entrainment deposition phenomenon; in addition, the experimental device has the advantages of experimental process visualization, high safety and easiness for installation and maintenance, etc.

Description

technical field [0001] The invention belongs to the technical field of experimental devices, and in particular relates to a pressure vessel and a method for simulating droplet entrainment in an upper chamber of a nuclear reactor. Background technique [0002] After a small break accident occurs in the reactor, with the successive opening of the automatic depressurization systems at all levels, the system pressure will continue to decrease, and the coolant stock in the reactor will also continue to decrease due to break leakage and water entrainment. When the liquid level in the pressure vessel falls below the outlet heat pipe section, a large amount of steam generated by the decay heat in the pressure vessel will continue to entrain the coolant from the outlet heat pipe section, further reducing the liquid level in the reactor pressure vessel and possibly A serious accident that eventually led to the core exposure and melting. This entrainment occurs in the upper chamber of...

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Problems solved by technology

In addition, some foreign countries have done some related experiments on the entrainment of the upper chamber of the reactor, but the parameter range of these experiments is relatively narrow, and cannot cover the parameter range of the modeled reactor operating conditions, or the simulation of physical properties such as entrainment has not been realized.

Such as the upper chamber entrainment experiment carried out by Oregon State University on the ATLATS experimental bench (K.B.Welter, Q.Wu, Y.You et al. Experimental investigation and theoretical modeling of liquid entrainment in a horizontal tee with a vertical-up branch. International Journal of Multiphase Flow, 30(2004), p.1451–1484), this experiment uses air-water as the working medium, but the medium in the reactor is water vapor-water, so it is inevitable to replace water vapor with air because Larger simulation errors are introduced due to differences in physical properties, mass and energy transfer, etc.

In addition, the ATLATS test pressure is slightly higher than normal pressure, which cannot cover the corresponding pressure range when entrainment occurs in the upper chamber after the reactor small breach accident

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