Hydrogen Injection System for BWR Startup and Shutdown
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Solution Overview
Problem
Conventional Hydrogen Water Chemistry systems in BWRs are unable to inject hydrogen during reactor startup and shutdown phases due to varying pressures and temperatures, leaving reactor support systems at risk of Inter-Granular Stress Corrosion Cracking (IGSCC) as hydrogen cannot be efficiently transported to recirculation piping and reactor internals.
Innovation Solution
A startup/shutdown hydrogen injection system that provides hydrogen at variable pressures up to 1,100 psig, using a hydrogen gas booster to match the changing operating pressures of reactor support systems during startup and shutdown, ensuring hydrogen delivery to high-pressure areas such as reactor water cleanup and feedwater recirculation lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional hydrogen injection systems are used at fixed low-pressure points, then hydrogen can be injected during normal operation, but hydrogen injection is impossible during startup and shutdown when support system pressures exceed conventional injection capabilities
Solution Approach 1:
The system employs a variable speed compressor that can dynamically adjust its operation across multiple speed ranges (first, second, and third speed ranges) to match the varying pressure requirements of the support system during different operational phases. This dynamic adaptation enables hydrogen injection at both low pressures during normal operation and high pressures during startup and shutdown, resolving the contradiction between fixed injection capability and variable pressure requirements.
Solution Approach 2:
The system changes operational parameters by switching between different compressor speed ranges and activating different injection paths based on the support system's current pressure. The controller monitors support system pressure and adjusts compressor speed and injection valve configuration accordingly, enabling the system to adapt from low-pressure injection during normal operation to high-pressure injection during startup and shutdown modes.
2Reliability
If hydrogen is not injected during startup and shutdown, then the injection system remains simple and reliable, but the recirculation piping and reactor internals are at high risk of IGSCC corrosion
Solution Approach 1:
The hydrogen injection system is designed to perform multiple functions across different operational modes. The same compressor and injection infrastructure serve both normal operation (low pressure) and startup/shutdown (high pressure) conditions, eliminating the need for separate injection systems. This multi-functionality provides continuous corrosion protection while avoiding the complexity of duplicate systems.
Solution Approach 2:
The system prepares for high-pressure injection requirements in advance by incorporating a compressor capable of operating in high-speed ranges and configuring injection paths that can handle elevated pressures. This preliminary capability ensures that when startup or shutdown occurs, the system can immediately provide hydrogen injection without requiring additional equipment or complex reconfiguration.
3Adaptability or versatility
If a high-pressure capable injection system is implemented, then hydrogen can be injected during all operational modes, but the system complexity and cost increase significantly
Solution Approach 1:
The compressor operation is segmented into distinct speed ranges (first, second, and third speed ranges) with specific injection paths activated for each range. This segmentation allows the system to use simpler, lower-pressure components during normal operation while reserving high-pressure capability only when needed during startup and shutdown, thereby reducing overall system complexity while maintaining full operational coverage.
Solution Approach 2:
The controller acts as an intermediary that monitors support system pressure and intelligently switches between different compressor speed ranges and injection paths. This intermediary coordination enables the system to automatically select the appropriate operational mode without requiring manual intervention or complex mechanical reconfiguration, simplifying the overall system architecture while achieving adaptability across all operational modes.
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 effectively mitigates IGSCC by ensuring continuous hydrogen injection at varying pressures and temperatures, protecting reactor support systems during startup and shutdown by maintaining hydrogen dissolution and transport to critical areas, thereby reducing corrosion risks.
Implementation Method 1
a hydrogen gas booster to match the changing operating pressures of reactor support systems during startup and shutdown
Implementation Method 2
the injected hydrogen causes a reduction in dissolved oxygen by lowering the radiolytic net production of hydrogen and oxygen in the core region of the reactor
Data Source
AI summary
A system for injecting hydrogen into Boiling Water Reactor (BWR) reactor support systems in operation during reactor startup and/or shutdown. The system the hydrogen injection system includes at least one hydrogen source, flow control equipment, and pressure control equipment. The pressure control equipment being configured to regulate a pressure of a hydrogen flow between the at least one hydrogen source and the at least one first BWR support system based upon an operating pressure of the at least one first BWR support system.