High-Pressure Hydrogen Injection for PWR Coolant Control
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Solution Overview
Problem
Existing hydrogen injection systems in pressurized water reactors face limitations such as low hydrogen feed rates, delayed effects, and the use of toxic wet chemistry solutions, which are harmful to the environment and personnel.
Innovation Solution
A high-pressure hydrogen injection system is introduced, featuring a high-pressure feeding pump, preferably a piston compressor, to inject hydrogen downstream of the high-pressure charging pumps, achieving a 40-fold increase in injection pressure and allowing for precise control of hydrogen injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If hydrogen is injected into the primary reactor coolant using low-pressure injection (downstream of suction side of charging pump), then the system is simpler to operate, but the hydrogen feed rate is limited and the injection process is temporarily inert with delayed effects
Solution Approach 1:
The patent changes the pressure parameter of hydrogen injection from low-pressure (downstream of suction side) to high-pressure (downstream of discharge side of charging pump). This parameter change enables faster hydrogen dissolution into the coolant, increasing the hydrogen feed rate and reducing the temporarily inert period while maintaining operational simplicity through automated pressure control
2Productivity
If wet chemistry systems (hydrazine or hydrogen peroxide) are used for injection, then hydrogen can be delivered, but the solutions are toxic, cancerous, corrosive, and harmful to the environment and personnel
Solution Approach 1:
The patent extracts and eliminates the harmful wet chemistry components (hydrazine, hydrogen peroxide) from the hydrogen delivery system. Instead, it uses pure gaseous hydrogen injected directly into the primary reactor coolant, thereby maintaining hydrogen delivery capability while removing toxicity, cancerous properties, corrosiveness, and environmental harm associated with wet chemistry solutions
Solution Approach 2:
The patent converts the previously harmful wet chemistry systems into a beneficial pure hydrogen gas injection system. The high-pressure hydrogen gas injection not only eliminates the harmful effects of wet chemistry but also provides faster hydrogen delivery and more reliable operation, turning a harmful system into a beneficial one
3Productivity
If high-pressure hydrogen injection is implemented (downstream of discharge side of charging pump), then the hydrogen feed rate increases and response time decreases, but the system complexity increases due to higher pressure requirements
Solution Approach 1:
The patent makes the high-pressure charging pump serve a dual function: both charging the reactor coolant and providing the high-pressure environment for hydrogen injection. This multi-functionality eliminates the need for separate high-pressure hydrogen injection equipment, thereby increasing hydrogen feed rate and reducing response time while minimizing the increase in system complexity
4Ease of operation
If nitrogen is used to flush the Volume Control Tank during startup, then the tank can be prepared for hydrogen injection, but nitrogen pollution occurs and C14 is created in the core
Solution Approach 1:
The patent extracts and eliminates nitrogen from the startup procedure. Instead of using nitrogen to flush the Volume Control Tank, the system directly introduces hydrogen gas into the primary reactor coolant through high-pressure injection, thereby avoiding nitrogen pollution and C14 creation in the core while maintaining ease of operation during startup
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 high-pressure hydrogen injection system enables efficient and fast hydrogen delivery, reducing startup time, minimizing nitrogen pollution, and enhancing hydrogen control with shorter response times, while also being modular and redundant for high availability.
Implementation Method 1
a high-pressure feeding pump, preferably a piston compressor or a membrane compressor, to inject hydrogen at any suitable position of the CVCS downstream the charging pump
Implementation Method 2
The advantage in terms of physics for the injection of hydrogen is diffusion with a specific pressure in a specific time via a specific surface while the pressure is approx. 40 times higher than for the low-pressure injection
Data Source
AI summary
A pressurized water reactor includes a primary reactor coolant circuit flown through by a primary reactor coolant during operation, and a chemical and volume control system for the primary reactor coolant. The chemical and volume control system includes, along the direction of flow of the primary reactor coolant, a letdown line, a high-pressure charging pump with a given discharge pressure, and a charging line leading to the primary reactor coolant circuit. The chemical and volume control system further includes a hydrogenation system with a hydrogen supply and a hydrogen feeding line. In order to achieve efficient and fast hydrogen injection into the primary reactor coolant, a high-pressure feeding pump is arranged in the feeding line to provide a gas pressure higher than the discharge pressure of the charging pump. The feeding line discharges into the charging line.