Vacuum helium leak checking method for condenser at power operation phase of nuclear power plant

Abstract

The invention provides a vacuum helium leak checking method for a condenser at a power operation phase of a nuclear power plant. According to the method, helium is sprayed to a vacuum boundary to be tested, a helium mass spectrograph is connected to a condenser vacuum pump exhaust pipeline to detect the helium flow value, and whether the tested area has leak can be judged and the magnitude of a leak point can be estimated according to the change condition of the helium flow value, so that the leak point can be accurately positioned. Compared with the prior art, the vacuum helium leak checking method for the condenser at the power operation phase of the nuclear power plant has the advantages of convenience in operation, high sensitivity, high leak checking efficiency, no harm to human body and the like.

Description

technical field [0001] The invention belongs to the field of nuclear power plant debugging, and more specifically, the invention relates to a vacuum leak detection method for a condenser in the power operation stage of a nuclear power plant. Background technique [0002] The vacuum degree of the condenser is the most important final parameter of the nuclear power plant generating unit, which directly affects the cycle thermal efficiency of the nuclear power plant. Therefore, ensuring sufficient vacuum tightness of the condenser is related to the economic benefits of the entire nuclear power plant. Since the condenser maintains a high negative pressure state during the power operation of the unit, the main reason for the poor dissolved oxygen vacuum in the condenser is that there is a leak in the system or equipment connected to it, and air enters it. [0003] In the disclosed nuclear power plant, during the conventional island cold state vacuum pumping and hot state vacuum p...

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Problems solved by technology

[0004] However, during the power operation stage of the unit, the pipelines and equipment at the main vacuum boundary of the secondary circuit are wrapped with insulation cotton and iron sheets, and all the equipment in the plant is put into use, so it is no longer possible to find potential and newly added leaks by conventional methods

Specifically, if the above-mentioned conventional method is still used to search for vacuum leaks, the following problems will occur: 1) Due to the large number of operating equipment in the factory building and the mixed noise, it is impossible to distinguish the suction sound of the vacuum leak point to judge the leak. 2) Since most of the vacuum boundary pipes and equipment have been wrapped by insulation cotton and iron sheets, it is impossible to directly find the vacuum leak point with the naked eye; 3) Since the unit is in the power operation stage, all equipment valves must be in the required state, Vacuum leaks cannot be eliminated by isolating part of the pipeline equipment; 4) For small leaks, because they are wrapped in insulation cotton, they cannot be verified by covering the film; 5) Since all construction scaffolding on site has been removed during the power operation stage, most of the vacuum The boundary area cannot be approached; 6) Due to the large number of equipment and pipelines, a large amount of manpower is required, but it is impossible to find out the vacuum leak point in a short time, and it is difficult to achieve the purpose of reducing the economic loss caused by it

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