An early depressurization system for containment accidents in nuclear power plants

Abstract

The invention relates to a decompression system for a containment vessel of a nuclear power plant at an early period of an accident. The decompression system comprises the containment vessel, a decompression mechanism and a negative-pressure compensation mechanism, wherein the decompression mechanism comprises a gas isolation container, a decompression draught fan and a decompression exhausting pipeline; the decompression exhausting pipeline penetrates through the inner and outer parts of the containment vessel and is used for communicating an inner cavity of the containment vessel and the gas isolation container; the decompression draught fan is arranged on the decompression exhausting pipeline; the negative-pressure compensation mechanism is communicated with the inner part of the containment vessel or is arranged in the containment vessel. According to the decompression system for the containment vessel, provided by the invention, the containment vessel can be decompressed at the early period of the accident, pressure soaring of the containment vessel, caused by mass-energy release in the vessel is remarkably alleviated and overpressure failures of the containment vessel are avoided; air in the containment vessel is pumped through the decompression mechanism and water steam is supplemented into the containment vessel through the negative-pressure compensation mechanism to remove an air component in the containment vessel, so that the performance of a passive containment vessel heat leading-out system can be remarkably improved.

Description

technical field [0001] The invention relates to the safety field of containment shells of nuclear power plants, in particular to an early decompression system for containment shell accidents of nuclear power plants. Background technique [0002] The airtight containment is an important barrier to prevent the leakage of radioactive materials in the event of an accident in a nuclear power plant. Normally, after an accident, the containment vessel will be isolated and become a closed space, and the sharply increased temperature and pressure are all borne by the containment vessel structure. This design requires the containment vessel to have a large free volume and shell thickness, and also requires the matching post-accident containment depressurization and heat removal system to have high performance. After the accident, the airtight containment of a nuclear power plant needs to face two problems. One is the export of reactor waste heat. If the waste heat export mechanism is...

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Problems solved by technology

China Nuclear Power Engineering Co., Ltd.'s invention patent titled passive containment accident pressure relief system with release gas containment function (CN102750993B) provides a passive pressure relief scheme for the early stage of a containment accident, but the technical scheme is only for relief. Due to the effect of pressure, there is still a large amount of residual air components in the shell, and there is a risk of hydrogen explosion

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