A method and system for measuring air exchange capacity

Abstract

The invention discloses a method for measuring air exchange volume, comprising: S1, injecting a tracer gas into a space to be measured by a constant injection method; S2, measuring the concentration of the tracer gas in the space to be measured, and determining the concentration according to the concentration Whether the tracer gas in the space to be tested is mixed with the air in the space to be tested evenly; S3. After confirming that the tracer gas in the space to be tested is mixed with the air in the space to be tested evenly, take a gas sample in the space to be tested and record At the sampling time, measure the concentration of the tracer gas in the sampled gas; S4, perform function fitting on the corresponding relationship between the concentration of the tracer gas in the sampled gas and the sampling time, to obtain a fitting function; S5, according to the fitting function and the injection amount of the tracer gas in the space to be tested, and calculate the air exchange rate of the space to be tested. The method and system provided by the invention can accurately measure the air exchange volume of a single space related to safety by using the constant injection method.

Description

technical field [0001] The invention relates to the fields of nuclear safety and civil safety, in particular to a method and system for measuring air exchange volume. Background technique [0002] At present, the main control room of some nuclear facilities, especially the key departments of nuclear power plants, pays more attention to the amount of unfiltered air leakage in this space. It is an important parameter related to the safety of the staff in the main control room. All nuclear power plants in the United States are required to measure the amount of unfiltered air in the main control room to ensure that the staff in the main control room will not be affected by accident conditions. It will be exposed to radiation exposure and chemical poisons beyond the design standard. [0003] For the main control room of a nuclear power plant, the air exchange characteristics of the space to be tested can be measured by injecting tracer gas. Specifically, the air exchange rate, t...

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Problems solved by technology

[0004] The American ASTM E741 standard recommends three tracer gas test methods to measure the internal leakage of unfiltered air in the main control room, which are concentration decay method, constant injection method and constant concentration method. In fact, constant injection is more widely used. However, historically, due to the limitation of the measurement accuracy of the instrument and the limitation of the test time, American companies often cannot achieve the concentration balance of the constant injection method that satisfies the condition of mass conservation when conducting the tracer test of the leakage measurement in the main control room. In many cases, they use the unbalanced concentration data measured in the tracer test but use the mass conservation formula to calculate the air exchange rate. This is a method adopted due to the limitation of the available test time in the main control room. Obviously unreasonable but helpless method

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