Multi-Stage Safety Injection Device for Reactor Coolant Control
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Solution Overview
Problem
Current safety injection systems for reactors are complex and require multiple systems to manage varying coolant flow rates during accidents, leading to inefficiencies and potential delays in pressure balancing during flow rate switching.
Innovation Solution
A multi-stage safety injection device that uses a safety injection tank, pressure balance line, and multiple safety injection lines with different heights and orifices to gradually adjust coolant flow rates based on reactor vessel pressure and water level, ensuring continuous coolant injection with reduced complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple safety injection systems are used to manage varying coolant flow rates, then the required coolant injection capability at different accident stages is achieved, but the system complexity increases and potential delays in pressure balancing occur
Solution Approach 1:
The safety injection line is divided into multiple segments (first safety injection line and second safety injection line) with different heights. Each segment serves a specific accident stage by providing coolant injection at different flow rates, eliminating the need for multiple separate systems while maintaining adaptability across different accident scenarios.
Solution Approach 2:
The single safety injection tank serves multiple functions by providing coolant injection at different flow rates through the multi-level injection lines. The same tank and injection mechanism handle both high flow rate (first stage) and medium flow rate (second stage) requirements, reducing system complexity while maintaining versatility.
2Productivity
If high flow rate coolant injection is used at the initial stage of accident, then the core level decrease is rapidly addressed, but the system requires complex multi-system coordination for subsequent stages
Solution Approach 1:
The injection system is segmented vertically with the first safety injection line positioned lower than the second safety injection line. This segmentation enables automatic flow rate reduction from high (first stage) to medium (second stage) based on the water level in the reactor vessel, eliminating complex coordination requirements while maintaining high initial injection capability.
Solution Approach 2:
The system dynamically adjusts flow rate based on the water level in the reactor vessel. As the water level decreases during the accident, the flow rate automatically transitions from high to medium through the multi-level injection lines, providing adaptive coolant injection without requiring complex control systems.
3Loss of time
If pressure balance is rapidly established between reactor vessel and safety injection tank, then the coolant injection timing is optimized, but the flow rate switching between stages may cause delays
Solution Approach 1:
The segmented injection lines at different heights create distinct flow paths that operate independently. The first safety injection line provides high flow rate injection while the second provides medium flow rate injection, allowing seamless transition between stages without disrupting pressure balance or causing delays.
Solution Approach 2:
The multi-level injection lines ensure continuous coolant injection without interruption during flow rate transitions. As the water level in the reactor vessel changes, coolant flow automatically transitions between the first and second injection lines, maintaining continuous cooling action and eliminating delays in flow rate switching.
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 simplifies coolant injection by varying flow rates stepwise, maintaining pressure balance and extending injection time, enhancing reliability and stability compared to active systems.
Implementation Method 1
a safety injection tank formed to contain coolant to be injected into a reactor vessel by a gravitational head of water when an accident occurs
Implementation Method 2
a pressure balance line connected to the reactor vessel and safety injection tank to form a pressure balance state between the reactor vessel and the safety injection tank
Implementation Method 3
connected to the safety injection tank with different heights to reduce a flow rate of coolant injected into the reactor vessel step by step according to the water level reduction of the safety injection tank
Data Source
AI summary
The present disclosure may disclose a multi stage safety injection device, including a safety injection tank formed to contain coolant to be injected into a reactor vessel by a gravitational head of water when an accident occurs in which the pressure or water level of the reactor vessel is decreased, a pressure balance line connected to the reactor vessel and safety injection tank to form a pressure balance between the reactor vessel and the safety injection tank, and a set of safety injection lines connected to the safety injection tank and the reactor vessel to inject coolant to the reactor vessel in a pressure balance state between the reactor vessel and the safety injection tank, and connected to the safety injection tank with different heights to reduce a flow rate of coolant injected into the reactor vessel step by step according to the water level reduction of the safety injection tank in order to inject coolant to the reactor vessel at multi stages.