Welding method of outer cylinder and bottom plate in base of lower core shell of high temperature gas-cooled reactor

Abstract

The invention discloses a method for welding an outer cylinder in a reactor core vessel base and a base plate in a high-temperature gas cooled reactor. By the adoption of the method, the maximum deformation of the base plate can be controlled to be 9.6 mm or below. An inner cylinder tool and an outer cylinder tool are placed on a site, then the base plate is placed on the inner cylinder tool and the outer cylinder tool, welding portions are preheated, the welding portion of the outer cylinder is divided into eight welding areas: a, b, c, d, e, f, g and h with the same arc length in the circumferential direction clockwise, positioned welding is conducted after preheating, and then a multi-layer multi-pass welding method is adopted. The multi-layer multi-pass welding method specifically comprises the steps of three-layer welding of an internal groove, three-layer welding of an external groove, welding of the fourth layer and the fifth layer of the internal groove, welding of the fourth layer and the fifth layer of the external groove, complete welding of the internal groove, and complete welding of the external groove. The method has the advantages that the maximum deformation of the base plate can be controlled to be 9.6 mm or below, welding is firm, the requirement of the nuclear power field for welding quality is met, and the service life of the base is prolonged.

Description

technical field [0001] The invention relates to a method for welding an outer cylinder and a bottom plate in a base of a lower core shell in a high-temperature gas-cooled reactor. Background technique [0002] With the introduction of the "fourth generation advanced nuclear energy system" concept, high temperature gas-cooled reactors are gradually characterized by their unique safety, wide range of uses, miniaturization, low investment, and short construction period following the introduction of the concept of modular high temperature reactors. And other characteristics have won the favor of more and more people of insight. [0003] The high-temperature gas-cooled reactor is an advanced reactor with the safety characteristics of the fourth-generation nuclear energy system. It is one of the six alternative reactor types in the fourth-generation nuclear energy system in the international nuclear energy field, and it is the only one that can achieve commercial operation before ...

AI Technical Summary

Problems solved by technology

[0009] The material of the base workpiece is 12Cr2MolR. Due to the high content of Cr and Mo in the material, there is a greater tendency to harden during welding, and the welding is very difficult.

The maximum deformation of the bottom plate should be controlled at ≤9.6mm, that is to say, within the processing allowance. The current conventional welding method cannot guarantee that the maximum deformation of the bottom plate is controlled at ≤9.6mm

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