Nuclear Reactor Containment Vent System with Passive Gas Extraction
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Solution Overview
Problem
The reactor containment vessel vent system in nuclear power plants faces challenges in continuously releasing steam to the atmosphere when power supply is lost, leading to potential pressure buildup due to reduced permeation performance of the noble gas filter.
Innovation Solution
The system includes a vent line with a noble gas filter allowing steam passage and a return pipe connecting the upstream portion to the reactor containment vessel, featuring an intermediate vessel to store non-permeating gases, utilizing passive components like relief and check valves to manage pressure without external power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a noble gas filter is installed to remove radioactive noble gases, then the removal of radioactive noble gases is improved, but the permeation performance of steam is reduced due to gas accumulation in the immediate upstream portion
Solution Approach 1:
The patent extracts the non-permeable gases (radioactive noble gases and other non-condensable gases) from the immediate upstream portion of the noble gas filter by introducing a return pipe that connects this portion back to the reactor containment vessel. This extraction prevents gas accumulation that would otherwise block steam permeation, thereby resolving the contradiction between removing radioactive noble gases and maintaining steam permeation performance.
Solution Approach 2:
The return pipe acts as an intermediary mechanism that facilitates the removal of accumulated non-permeable gases from the immediate upstream portion of the noble gas filter. By providing this intermediate pathway, the system maintains both the radioactive noble gas removal function and the steam permeation performance without direct conflict between these two functions.
2Productivity
If an active device such as a pump is used to return gas to the reactor containment vessel, then the gas removal function is improved, but the system becomes dependent on power supply which may be lost
Solution Approach 1:
The patent implements a self-service system where the return pipe utilizes the existing pressure differential between the immediate upstream portion of the noble gas filter and the reactor containment vessel to drive gas flow automatically. This passive mechanism requires no external power supply or active devices, eliminating power dependency while maintaining reliable gas return function even during power outages.
Solution Approach 2:
The patent replaces the proposed active mechanical system (pump) with a passive system that relies on natural pressure differential and flow dynamics. This substitution eliminates the need for powered mechanical components while achieving the same gas return function, thereby improving reliability by removing power supply dependency.
3Quantity of substance
If gas containing noble gases stays in the immediate upstream portion of the noble gas filter, then the partial pressure of noble gases is increased, but the steam discharge function is hindered
Solution Approach 1:
The return pipe extracts accumulated non-permeable gases (including radioactive noble gases) from the immediate upstream portion of the noble gas filter and returns them to the reactor containment vessel. This extraction maintains low partial pressure of non-permeable gases in the immediate upstream portion, preventing blockage of steam permeation while preserving the concentration of noble gases in the overall vent gas stream for continued removal.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration ensures continuous steam release and pressure reduction in the reactor containment vessel, even during power outages, maintaining permeation performance and preventing unnecessary pressure drops.
Implementation Method 1
a noble gas filter that allows at least steam to pass through and that does not allow radioactive noble gases to pass through among vent gas
Implementation Method 2
a relief valve that operates when pressure in the immediate upstream portion of the noble gas filter exceeds a set value to reduce the pressure
Implementation Method 3
a check valve that allows the gas to flow into the immediate upstream portion of the noble gas filter from the intermediate vessel
Data Source
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AI summary
The invention provides a reactor containment vessel vent system capable of continuously releasing steam generated in a reactor containment vessel to the atmosphere even when a power supply is lost. In the reactor containment vessel vent system (15), the noble gas filter (23) that allows steam to pass through but does not allow radioactive noble gases to pass through among vent gas discharged from the reactor containment vessel (1) is provided at a most downstream portion of the vent line. An immediate upstream portion of the noble gas filter (23) and the reactor containment vessel (1) are connected to each other by the return pipe (24a, 24b) via the intermediate vessel (100). Further, when the radioactive noble gases having pressure equal to or higher than predetermined pressure stays in the immediate upstream portion of the noble gas filter (23), the staying radioactive noble gases flows into the intermediate vessel (100) by the relief valve (25). Thus, the noble gas filter (23) does not lose steam permeability, and the reactor containment vessel vent system (15) can continuously release the steam to the atmosphere.