Melt Wire Array for Passive Nuclear Reactor Temperature Measurement
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Solution Overview
Problem
Current methods for monitoring temperatures within nuclear reactors, especially in harsh reactor environments, face challenges such as high costs and radiation-induced de-calibration of active sensors, and the manufacturing process for melt wire capsules is complex and time-consuming, making it difficult to accurately determine maximum temperatures.
Innovation Solution
The development of a sensor using additive manufacturing to create a melt wire array with varying melting temperatures, allowing for spatial resolution and passive temperature measurement by forming melt wires with controlled compositions and geometries on a substrate, which can be easily analyzed post-irradiation using x-ray computed tomography.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If active temperature sensors (thermocouples, solid-state thermistors) are used for real-time temperature monitoring, then real-time temperature data can be obtained, but the sensors are expensive to install and subject to radiation-induced de-calibration
Solution Approach 1:
The patent uses disposable melt wires with known melting points that are placed in capsules. These melt wires are inexpensive compared to active sensors and do not require calibration. After irradiation, the capsules are retrieved and examined to determine if melting occurred, providing temperature data without the reliability issues of electronic sensors in radiation environments.
Solution Approach 2:
The patent replaces electronic active sensing systems with a passive mechanical/thermal system. Instead of using electronic thermocouples or thermistors that require power and calibration, the system uses the physical melting phenomenon of materials at specific temperatures. This substitution eliminates radiation-induced de-calibration issues while providing temperature measurement capability.
2Measurement precision
If multiple melt wires are placed in a single capsule for temperature monitoring, then some level of temperature monitoring is achieved, but the manufacturing process is difficult and time-consuming
Solution Approach 1:
The patent segments the temperature monitoring function into multiple individual melt wires, each with a specific melting point, placed within a single capsule. This allows temperature monitoring at multiple discrete temperature levels simultaneously. The segmentation approach enables simple manufacturing - each capsule contains pre-fabricated melt wires of known compositions, avoiding complex assembly processes while achieving multi-level temperature monitoring.
3Ease of manufacture
If traditional melt wire capsules are used for passive temperature monitoring, then cost-effective temperature estimation is achieved, but evaluating the wires during post irradiation examination is not easy
Solution Approach 1:
The patent applies color changes as visual indicators on or near the melt wires within the capsule. After irradiation, these color changes provide immediate visual cues about the thermal history and melting status of the wires, making post-irradiation examination much easier. The color-coded system allows rapid assessment without complex analytical equipment, maintaining cost-effectiveness while solving the detection difficulty.
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 solution provides a cost-effective and efficient means to determine maximum temperatures in nuclear reactors, overcoming the limitations of active sensors and complex manufacturing processes, while offering improved spatial resolution and ease of analysis.
Implementation Method 1
a plurality of melt wires within a cavity defined within the substrate, at least one melt wire of the plurality of melt wires exhibiting a variable melting temperature along a length of the at least one melt wire
Data Source
AI summary
A sensor for passively measuring a maximum temperature within a nuclear reactor comprises a substrate, and a plurality of melt wires within a cavity defined within the substrate, at least one melt wire of the plurality of melt wires exhibiting a variable melting temperature along a length of the at least one melt wire. Related sensors and methods of forming the sensors are also disclosed.