Fiber Optic Leak Detection for Tight Spent Fuel Pool Spaces
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Solution Overview
Problem
Existing leak detection systems for deionized water in nuclear power plants require large mechanical structures and are inefficient in small spaces, leading to increased volume requirements and construction costs, while also being limited by the need for ionized or radioactive indicators.
Innovation Solution
The use of fiber optic and Time Domain Reflectometry (TDR) cables embedded in the pool walls and floors to detect deionized water leaks, which are compact and can identify leak locations with high precision using electromagnetic signals and optical fiber technology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional leak chase systems with mechanical structures and sight glasses are used, then leak detection capability is achieved, but space requirements and construction costs increase significantly
Solution Approach 1:
The patent replaces traditional mechanical leak chase systems with fiber optic cable-based detection systems. Instead of using mechanical structures like sight glasses and thick leak chases, the system uses fiber optic cables embedded in the pool structure that detect water presence through optical signal changes, thereby eliminating the need for large mechanical components and reducing space requirements
Solution Approach 2:
The patent changes the detection parameter from mechanical water level observation to optical signal detection. By monitoring changes in optical properties (such as light transmission or reflection) along the fiber optic cable, the system can detect leaks without requiring physical space for mechanical measurement structures, thus resolving the contradiction between detection reliability and space efficiency
2Reliability
If traditional leak chase systems are used, then leak detection is possible, but construction costs and maintenance requirements increase
Solution Approach 1:
The patent substitutes complex mechanical leak chase installations with simpler fiber optic cable embedding. The fiber optic cables can be integrated into existing pool structures during construction, eliminating the need for separate installation of thick leak chases and sight glass components, thereby reducing construction costs and simplifying manufacturing
Solution Approach 2:
The fiber optic cable serves multiple functions: it acts as both a structural reinforcement element and a detection sensor. This multi-functionality eliminates the need for separate dedicated leak detection components, reducing overall construction costs and simplifying the manufacturing process while maintaining reliable leak detection capability
3Quantity of substance
If deionized water is used in the pool, then water purity is maintained, but leak detection becomes difficult without ionized or radioactive indicators
Solution Approach 1:
The patent replaces chemical detection methods (relying on ionized or radioactive indicators) with optical detection using fiber optic cables. The fiber optic system detects water presence through physical optical property changes rather than chemical indicators, allowing leak detection in deionized water without compromising water purity
Solution Approach 2:
The fiber optic cable acts as an intermediary detection medium that translates physical water contact into detectable optical signals. This intermediary approach allows the system to detect leaks in deionized water without requiring the water itself to contain detectable ions or radioactive materials, thus maintaining water purity while enabling effective leak detection
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
Reduces space requirements and construction costs by enabling precise leak detection in small spaces without the need for large mechanical structures, while maintaining low maintenance and operation simplicity.
Implementation Method 1
probes of fiber optic and/or Time Domain Reflectometry (TDR) cables that provide at least one of an electric and electromagnetic signal upon coming in contact with a liquid from the pool
Implementation Method 2
Time Domain Reflectometry (TDR) cables that provide at least one of an electric and electromagnetic signal upon coming in contact with a liquid from the pool. An interrogator may be multiplexed with several of the cables and generate interrogation signals whose reflection determines an exact position along the cable of leakage contact
Data Source
AI summary
Leakage detection systems and methods of monitoring leakage using probes of fiber optic and/or Time Domain Reflectometry (TDR) cables that provide at least one of an electric and electromagnetic signal upon coming in contact with a liquid from the pool. An interrogator may be multiplexed with several of the cables and generate interrogation signals whose reflection determines an exact position along the cable of leakage contact. The cables may be run under a floor and/or wall of a spent fuel pool or other liquid volume in a nuclear power plant. Leakage even of deionized water near room temperature may be detectable. The cables may be a single serpentine cable or several straight cables wrapping around the volume. The cables may be small, such as 10 millimeters or less in diameter. Cables may be run behind liners at any pitch or interval, potentially between supporting structures and the liner.