Two-Stage Reactor Heat Exchanger for Hydride Moderator Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing heat pipe-based cooling systems for nuclear reactors with hydride moderators face challenges in maintaining stability at elevated temperatures, as hydride materials like yttrium hydride and zirconium hydride undergo hydrogen dissociation, compromising moderation capabilities without increasing design complexity.
Innovation Solution
A two-stage heat exchanger configuration where external working fluid first traverses moderator heat pipes before power heat pipes, ensuring optimal temperature differentials and insulation between fissile material and moderator cells, preventing hydrogen dissociation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If heat pipe-based cooling systems are used for nuclear reactors with hydride moderators at elevated temperatures, then energy generation efficiency is improved, but hydrogen dissociation in hydride materials occurs compromising moderation capabilities
Solution Approach 1:
The cooling system is segmented into two distinct circuits: a primary cooling circuit that contacts the moderator heat pipes and maintains lower temperatures to prevent hydrogen dissociation, and a secondary power conversion circuit that contacts the fuel cell heat pipes and operates at higher temperatures for efficient energy generation. This segmentation allows each circuit to be optimized for its specific function without compromising the other.
Solution Approach 2:
Different temperature conditions are applied to different parts of the reactor system. The moderator regions are maintained at lower temperatures through the primary cooling circuit to preserve hydride stability, while the fuel cell regions are maintained at higher temperatures through the secondary power circuit to maximize energy generation efficiency. Each region receives the temperature quality it needs for its specific function.
2Temperature
If separate cooling circuits are implemented for moderator and fuel cells, then temperature control is improved preventing hydrogen dissociation, but system complexity increases
Solution Approach 1:
The two separate cooling circuits (primary moderator cooling and secondary power conversion) are merged into a single integrated heat exchanger assembly where the primary and secondary circuits exchange thermal energy through a common structure. This merging allows independent temperature control for each circuit while sharing common infrastructure, thereby reducing overall system complexity compared to completely separate systems.
Solution Approach 2:
The heat exchanger assembly serves multiple functions simultaneously: it acts as the primary cooling system for moderator heat pipes, the secondary power conversion system for fuel cell heat pipes, and a thermal energy exchange interface between the two circuits. This multi-functionality reduces the need for separate dedicated components for each function.
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
The system maintains optimal energy generation while preventing hydrogen dissociation in moderator cells, reducing design complexity and potential failure modes by ensuring cooler temperatures for moderator cells and higher temperatures for fuel cells.
Implementation Method 1
a first plenum configured to envelope a moderator heat pipe extending from the core of the nuclear reactor
Implementation Method 2
Heat pipe-based cooling systems for nuclear reactors
Implementation Method 3
the first plenum and the second plenum are in fluid communication and configured such that the external fluid must traverse the first plenum and over the moderator heat pipe before entering the second plenum and traversing over the power heat pipe
Implementation Method 4
transferring, via the working fluid, thermal energy away from a power heat pipe extending from the core of the nuclear reactor
Data Source
AI summary
A heat exchanger for cooling a nuclear reactor core is disclosed herein. The heat exchanger can include a first stage including an input configured to receive a working fluid from an external source into the heat exchanger, and a first plenum configured to envelope a moderator heat pipe extending from the nuclear reactor core. The heat exchanger can further include a second stage including an output configured to remove a working fluid from the heat exchanger to the external source, and a second plenum configured to envelope a power heat pipe extending from the nuclear reactor core, wherein the first plenum and the second plenum are in fluid communication and configured such that the external fluid must traverse the first plenum and over the moderator heat pipe before entering the second plenum and traversing over the power heat pipe.