Nuclear Containment Sampling Line Vacuum Transport
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Solution Overview
Problem
Current sampling systems for nuclear reactor containment atmospheres face challenges in accurately determining gas components due to steam content assumptions under saturation conditions, leading to potential misinterpretation of explosive conditions and inappropriate countermeasures, and are inadequate for inert conditions and high radiation levels.
Innovation Solution
A sampling system that maintains a vacuum state during sample transport through a capillary sampling line with a restriction device to prevent steam condensation and uses a combination of thermal conductivity and heat of reaction methods for accurate hydrogen concentration measurement, independent of oxygen concentration, ensuring reliable analysis of containment atmosphere components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If measurement gas drying is carried out in an analysis cubicle outside the reactor containment, then hydrogen concentration can be measured by thermal conductivity analyzer, but the true hydrogen concentration cannot be determined accurately due to incorrect steam content assumptions
Solution Approach 1:
The patent introduces a sampling line as an intermediary component that directly connects the reactor containment atmosphere to the analysis system. This sampling line serves as a mediator that transports a representative sample without requiring assumptions about steam content, thereby enabling accurate hydrogen concentration measurement while eliminating the unreliable saturation assumption step.
Solution Approach 2:
The patent replaces the mechanical/thermodynamic approach of assuming saturation conditions and performing gas drying in an analysis cubicle with a direct sampling system. Instead of relying on thermal conductivity analysis with correction factors based on steam content assumptions, the system uses direct sampling to obtain accurate measurements without these problematic mechanical/thermodynamic assumptions.
2Productivity
If direct measurement systems are used inside the reactor containment, then real-time monitoring is possible, but measurement reliability is insufficient due to aggressive conditions with high radiation and chemical reactivity
Solution Approach 1:
The patent extracts the measurement function from the aggressive environment inside the reactor containment by taking atmospheric samples through a sampling line and transporting them to an analysis system located outside the containment. This extraction allows real-time monitoring capability while eliminating the measurement reliability problems caused by direct exposure to high radiation and chemical reactivity conditions.
Solution Approach 2:
The sampling line acts as an intermediary that bridges the aggressive containment environment and the safe analysis system. It enables real-time sample transport without requiring the analysis equipment to be directly exposed to harmful conditions, thus maintaining both productivity and reliability.
3Measurement precision
If sampling systems are used to take atmosphere samples, then analysis outside containment is possible, but steam condensation may occur during transport affecting measurement accuracy
Solution Approach 1:
The patent changes the pressure parameter of the sampling line to maintain a vacuum state during sample transport. This parameter change prevents steam condensation by keeping the sample in a superheated state, thereby maintaining measurement precision while controlling temperature effects during transport.
Solution Approach 2:
The patent creates an inert environment in the sampling line by maintaining a vacuum state, which prevents steam condensation and chemical reactions during transport. This inert environment protects the sample integrity and ensures accurate measurement of gas components.
4Measurement precision
If correction factors are applied based on saturation conditions, then hydrogen concentration can be calculated, but the correction is inaccurate due to varying atmosphere states from saturation to severely overheated conditions
Solution Approach 1:
The patent replaces the calculation-based correction method with a direct measurement approach. Instead of calculating hydrogen concentration using correction factors that assume saturation conditions, the system directly measures the sample in its actual state, eliminating the need to adapt to varying atmosphere states through complex corrections.
Solution Approach 2:
The sampling line serves as an intermediary that preserves the actual state of the containment atmosphere during transport. This allows direct measurement of hydrogen concentration without requiring adaptation to different atmosphere states, as the sample maintains its original conditions from the containment environment.
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
Enables reliable and accurate determination of containment atmosphere conditions, reducing the risk of inappropriate countermeasures and maintaining operational safety by maintaining sample overheating and minimizing activity release, allowing for precise management and control of incident responses.
Implementation Method 1
A sampling system (1) which is constructed to transfer the sample in the overheated state to the gas analyzer or separator (18) of the analysis system (14)
Implementation Method 2
limiting the pressure in the sampling line to a maximum of about 60% of the pressure in the reactor containment after an inflow of a sample into the sampling line
Implementation Method 3
the hydrogen concentration of the dried gas subsequently being measured by using a thermal conductivity analyzer
Implementation Method 4
hydrogen sensors which operate on the heat of reaction principle can also be directly inserted in reactor containments
Data Source
AI summary
A sampling system for taking a sample from the atmosphere in a reactor containment of a nuclear plant, includes a sampling line which is connected to a vacuum system and to an analysis system. The sampling line opens into the reactor containment and has a restriction device connected upstream thereof on the gas side for connection to the atmosphere in the reactor containment. A method for taking such a sample is also provided.