Passive Coolant Injection System for Nuclear Reactor Safety
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Solution Overview
Problem
Current safety systems in nuclear power generation, particularly in pressurized water reactors, face challenges in effectively injecting coolant into the reactor pressure vessel at elevated pressures without relying on external power or complex systems, which can introduce additional risks and inefficiencies.
Innovation Solution
A passive coolant injection system that includes a make-up tank with a tank inlet and outlet, configured to switch between operating and fault response conditions, allowing coolant to flow from the tank into the reactor pressure vessel using residual pressuriser pressure, thereby preventing backflow and reducing system size and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high-head pumps are used for emergency injection of coolant into the reactor pressure vessel, then coolant injection effectiveness is improved, but system complexity and dependency on external power input increase
Solution Approach 1:
The invention extracts the essential function of coolant injection from complex active pump systems and implements it through a simplified passive make-up tank system that relies on pre-stored pressurized coolant and automatic valve actuation, eliminating the need for complex control systems and external power input during fault conditions
Solution Approach 2:
The make-up tank system is designed to automatically activate and inject coolant without external power input or complex control systems. The system uses pre-stored pressurized coolant that automatically flows when the pressuriser level drops, providing self-service emergency cooling functionality
2Productivity
If emergency core cooling systems are initiated to rapidly depressurise the reactor pressure vessel, then coolant injection is achieved, but plant operating conditions are highly disrupted
Solution Approach 1:
The invention applies local quality by targeting coolant injection specifically to the pressuriser vessel through the make-up tank system, rather than globally depressurizing the entire reactor pressure vessel. This localized approach restores pressuriser level without disrupting overall plant operating conditions
3Stress or pressure
If the pressuriser empties due to coolant volume reduction, then system pressure control is lost, but reactor core uncovering risk increases
Solution Approach 1:
The make-up tank is pre-filled with pressurized coolant and positioned to automatically activate when the pressuriser level drops. This preliminary preparation ensures that coolant injection begins immediately upon pressuriser emptying, preventing reactor core uncovering before it can occur
Solution Approach 2:
The make-up tank acts as an intermediary system between the pressuriser and the reactor core cooling system. It receives pressurized coolant from the pressuriser and automatically injects it back into the pressuriser when levels drop, mediating the pressure control function and preventing core uncovering
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
This solution enables a compact, efficient, and safer core cooling system that can operate at high pressures without depressurization, reducing the risk of reactor core exposure and fuel melt, while minimizing the risk of pump failures associated with active systems.
Implementation Method 1
allowing coolant to flow from the tank into the reactor pressure vessel using residual pressuriser pressure
Data Source
AI summary
A coolant injection system for a nuclear power generation system includes the coolant injection system, and method of operation of the coolant injection system. The nuclear power generation system includes a reactor pressure vessel having a reactor core, a pressuriser in fluid communication with the reactor pressure vessel, and the injection system, which comprises a make-up tank having a tank inlet and a tank outlet. The injection system has an operating condition, and a fault response condition, and is configured to switch between these conditions when coolant level in the pressuriser drops below a threshold level. In the operating condition, the tank outlet is isolated from the reactor pressure vessel such that coolant is retained in the make-up tank, and the tank inlet is in fluid communication with the reactor pressure vessel and the pressuriser.