Integral Reactor Passive Safety System Design
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Solution Overview
Problem
Integral reactors face challenges in maintaining safety and water level during a loss of coolant accident due to high manufacturing costs, complexity in safeguard vessel design, and reliance on active systems for residual heat removal, which are not suitable for long-term operation without external power.
Innovation Solution
A passive safety system combining core makeup tanks, safety injection tanks, and passive residual heat removal systems using natural forces like gravity and gas pressure to supply water and remove heat without active equipment or safeguard vessels, ensuring stable operation for extended periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a safeguard vessel is used to maintain pressure balance for gravity-driven safety injection, then the reactor can achieve passive safety injection, but the manufacturing cost and system complexity increase significantly
Solution Approach 1:
The patent removes the safeguard vessel from the system entirely, extracting the pressure balance function to be achieved through alternative means (atmospheric pressure reference and gravity head) rather than through a complex pressurized vessel structure
Solution Approach 2:
The system uses natural atmospheric pressure and gravity to drive the safety injection process without requiring active pressure control systems or complex safeguard vessels, allowing the system to self-regulate based on environmental conditions
2Productivity
If active safety injection pumps are used to maintain water level, then the injection flow rate can be controlled, but the system requires external power supply which may not be available during accidents
Solution Approach 1:
The patent replaces the mechanical pump system (requiring electrical power) with a gravity-driven passive injection system that uses natural forces to achieve water injection without external power sources
Solution Approach 2:
The safety injection system uses natural gravity and pressure differential to automatically inject water into the reactor core without requiring external control systems or power sources, enabling autonomous operation during accidents
3Speed
If pressurized-type safety injection tanks are used for rapid coolant injection, then the injection speed is improved, but the system cannot operate for extended periods without significant residual heat removal capability
Solution Approach 1:
The patent combines the rapid injection capability of pressurized tanks with the sustained operation capability of passive residual heat removal systems, creating an integrated system that can operate effectively both rapidly and for extended periods
Solution Approach 2:
The safety system is designed to perform multiple functions: rapid coolant injection during initial accident phases and sustained residual heat removal during extended periods, making the system adaptable to different accident scenarios and timeframes
4Device complexity
If gravity-driven core makeup tanks are used for safety injection, then the system is simpler and passive, but the injection flow rate is low due to low gravitational head
Solution Approach 1:
The patent merges gravity-driven tanks with pressurized safety injection tanks to combine the simplicity and passive operation of gravity systems with the high flow rate capability of pressurized systems
Solution Approach 2:
The system uses a composite approach combining different injection mechanisms (gravity and pressure) to achieve both simplicity and high performance, analogous to using composite materials to combine properties of different materials
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 safety systems, maintains reactor water levels, and effectively removes residual heat for extended periods without external power, enhancing reactor safety and reducing manufacturing costs.
Implementation Method 1
filled therein with water and nitrogen gas, and supplies the water into the reactor
Implementation Method 2
stores water therein, and supplies the water into the reactor through the second safety injection line
Implementation Method 3
passive residual heat removal systems connected with a feedwater line and a steam line connected with a steam generator installed in the reactor to remove residual heat from the reactor
Data Source
AI summary
A passive safety system includes a containment, a reactor in the containment, a plurality of safety injection tanks connected with the reactor and having water and nitrogen gas to supply water thereof into the reactor through a safety injection line communicating to the first safety injection line upon a loss of coolant accident, a plurality of core makeup tanks connected with the reactor to supply water thereof into the reactor through a second safety injection line communicating to a safety injection line upon the loss of coolant accident, and a plurality of passive residual heat removal systems to remove residual heat from the reactor upon the loss of coolant accident or a non-loss of coolant accident. The water in each of the safety injection tank is stably supplied to the reactor for many hours by a differential head resulting from gravity or gas pressure.