Combined square fuel assembly, reactor core and two-pass flowing method of super-critical water reactor

Abstract

The invention provides a combined square fuel assembly, a reactor core and a two-pass flowing method of a moderator and a coolant, which are suitable for a super-critical water reactor. The fuel assembly consists of 4 same child components arranged in a 2*2 square form, wherein each child component consists of multiple fuel rods arranged in a square grid form, a water rod is arranged in a central area, and a guide tube of a crossed control rod and a conduit of the water rod are placed above the component and a conduit of the water rod and a moderator duct are placed below the component; the reactor core is divided into first and second pass areas; the moderator flows into the space between the water rod and the child component from top to bottom in both passes; the coolant flows into a first pass fuel area from top to bottom; and the moderator and the coolant flow into a second pass fuel area from bottom to top after being stirred and mixed below the reactor core and flow out of the reactor core. According to the combined square fuel assembly, the reactor core and the two-pass flowing method of the super-critical water reactor, the moderator and the coolant as well as the different pass coolants in the components and the reactor core can be effectively shunted when the fuel rod is fully and uniformly moderated, the structural materials are reduced and the feasibility and safety are high.

Description

technical field [0001] The invention relates to a nuclear reactor fuel assembly, a reactor core composed of the fuel assembly, and a moderator and coolant flow method, in particular to a combined square fuel assembly suitable for a supercritical water reactor, a reactor stack Core, moderator and coolant dual flow method. Background technique [0002] Supercritical water reactor is one of the most promising generation IV nuclear energy systems, which has outstanding advantages such as high unit thermal efficiency and simplified system. In order to further improve the thermal efficiency, the supercritical water reactor adopts a higher core outlet temperature (500°C) and a larger core inlet and outlet temperature difference (500°C / 280°C), and the coolant mass flow rate is about 1 / of that of the pressurized water reactor 10. As a result, the design of supercritical water reactor components needs to solve two very prominent problems: high fuel pellet and fuel rod cladding tempe...

AI Technical Summary

Problems solved by technology

In order to further improve the thermal efficiency, the supercritical water reactor adopts a higher core outlet temperature (500°C) and a larger core inlet and outlet temperature difference (500°C / 280°C), and the coolant mass flow rate is about 1 / of that of the pressurized water reactor 10. As a result, the design of supercritical water reactor components needs to solve two very prominent problems: high fuel pellet and fuel rod cladding temperature, and a sharp drop in reactivity due to severe neutron moderation

The coolant flow is long, the flow resistance and core pressure drop are relatively large, which is extremely detrimental to the performance and safety of the core

(3) In order to divert the coolant of the 1st, 2nd, and 3rd processes, a closed and heat-insulated chamber must be set in the lower chamber, resulting in the inability to install a flow distributor at the bottom of the fuel assembly, which reduces the safety margin of the core

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