Nuclear Feed System Vapor Pressure Control
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Solution Overview
Problem
Existing feed systems for nuclear reactors face challenges in maintaining long-term operational safety and preventing chemical decomposition of absorber liquids, particularly boron solutions, due to high temperatures and interactions with container materials, which can lead to pressure instability and corrosion.
Innovation Solution
A feed system with a spatially separate pressure tank and storage tank, using a propellant fluid to maintain operating pressure through a vapor cushion, with an adjustable heating device and an overflow line for pressure equalization, minimizing chemical and thermal interactions between the absorber liquid and propellant fluid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the absorber liquid is stored under high pressure using a nitrogen cushion, then the feed process can be initiated quickly, but the system requires complex nitrogen supply infrastructure and large space
Solution Approach 1:
The patent changes the state parameter of water from liquid to vapor by heating, creating a vapor cushion that provides pressure. This eliminates the need for nitrogen storage and supply systems while achieving the same pressure-generation function. The vapor cushion is created by heating water in the lower portion of the container, and the vapor rises to provide uniform pressure on the absorber liquid.
Solution Approach 2:
The patent uses water as a disposable consumable to generate vapor pressure, replacing expensive and complex nitrogen infrastructure. The water is heated to create vapor, and after use, the system can be refilled with fresh water. This approach eliminates the need for permanent nitrogen storage tanks and supply lines.
2Stress or pressure
If nitrogen is used to maintain pressure in the storage container, then operating pressure is achieved, but nitrogen dissolves in the absorber liquid and impairs condenser cooling efficiency
Solution Approach 1:
The patent extracts the harmful nitrogen gas from the system and replaces it with water vapor. By using water as the pressure-generating medium instead of nitrogen, the harmful dissolution effect is eliminated. The water vapor cushion provides the necessary pressure without introducing non-condensable gases that would impair condenser cooling.
Solution Approach 2:
The patent creates an inert environment using water vapor instead of nitrogen. The vapor cushion provides pressure while being harmless to the absorber liquid and condenser system. Water vapor is naturally compatible with the boric acid solution and does not cause the harmful effects associated with nitrogen dissolution.
3Stress or pressure
If the absorber liquid is heated to generate pressure, then pressure is achieved quickly, but chemical decomposition and corrosion of container walls occur over long storage periods
Solution Approach 1:
The patent segments the pressure-generation function from the storage function by using separate water and absorber liquid portions. The water in the lower portion is heated to generate vapor pressure, while the absorber liquid in the upper portion remains cool and chemically stable. This spatial segmentation prevents thermal and chemical degradation of the absorber liquid while maintaining the necessary pressure.
Solution Approach 2:
The patent introduces water vapor as an intermediary medium to transmit pressure from the heated water portion to the absorber liquid. The vapor cushion acts as a mediator that provides pressure without direct thermal contact between the heat source and the absorber liquid, preventing chemical decomposition and corrosion.
4Reliability
If a separate pressure vessel with propellant fluid is used, then chemical and thermal interactions are minimized, but device complexity increases
Solution Approach 1:
The patent merges the pressure vessel and storage container into a single integrated unit. The lower portion contains water for pressure generation, while the upper portion stores the absorber liquid. The overflow line connects the two portions, allowing vapor to rise and pressure to equalize. This integration eliminates the need for separate vessels and complex interconnections while maintaining chemical and thermal separation.
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 design ensures high operational safety by preventing chemical decomposition and maintaining pressure stability over long periods, allowing for quick and complete feeding of the absorber liquid into the reactor core while avoiding temperature shocks and corrosion.
Implementation Method 1
part of which is evaporated by the action of a heating device (18), so that a vapor cushion (20) forms in the upper region (10')
Implementation Method 2
this vapor cushion forces the cooling liquid through a feed line connected in the bottom area of the pressure vessel into the reactor core while at the same time expanding
Implementation Method 3
the required operating pressure is achieved by heating the cooling liquid held in a pressure storage tank by a heating device arranged in the pressure storage tank
Data Source
Figure 1
Figure 2
AI summary
A feeding system (2) for an absorber liquid (4) containing a neutron poison, in particular for a quick shut-down of a nuclear reactor, having a storage container (6) for the absorber liquid (4) is to be designed for high operational reliability with simple construction. In particular, a chemical decomposition of the absorber liquid (4) or corrosion of the container wall (10) of the storage container (6) is to be excluded. For this purpose, the invention provides for the storage container (6) to be connected to a pressure container (16) via an overflow line, wherein the pressure container (16) is filled with a motive fluid (14).