Oxygen Control in Liquid Metal Reactor Coolant
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Solution Overview
Problem
Nuclear reactor plants with liquid-metal coolants face corrosion issues due to the dissolution of protective oxide coatings in the coolant, leading to increased corrosion rates, which existing methods struggle to control effectively.
Innovation Solution
A method and device for controlling oxygen concentration in the coolant using a mass-exchange apparatus and a disperser, in conjunction with an oxygen sensor, to maintain optimal oxygen levels, activating or deactivating these components based on real-time measurements to prevent corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If oxygen is supplied to the coolant to maintain protective oxide coatings, then corrosion resistance is improved, but oxygen concentration control becomes difficult leading to either insufficient protection or excessive oxidation
Solution Approach 1:
The patent implements a feedback control system using oxygen sensors to monitor oxygen concentration in the coolant and automatically adjust oxygen supply rate. The control unit receives sensor signals and modulates the oxygen injection to maintain optimal concentration levels, resolving the contradiction between ensuring adequate corrosion protection and preventing excessive oxidation.
Solution Approach 2:
The system uses the coolant's own oxygen consumption characteristics (as structural materials diffuse into coolant and consume oxygen) as the basis for control. By monitoring the natural oxygen depletion rate and matching oxygen supply to this consumption, the system achieves self-regulating corrosion protection without external intervention.
2Object-affected harmful factors
If oxygen concentration in coolant is increased to prevent coating dissolution, then corrosion rate decreases, but measurement and control of oxygen concentration becomes difficult
Solution Approach 1:
The patent replaces difficult chemical measurement methods with electrical sensing technology. Oxygen sensors with solid electrolyte membranes convert oxygen concentration measurements into electrical signals that can be easily processed and controlled, overcoming the difficulties of direct oxygen measurement in liquid metal coolants.
Solution Approach 2:
The patent introduces solid electrolyte membranes as intermediaries between the oxygen-containing coolant and the sensing electrode. These membranes selectively transport oxygen ions while blocking other coolant components, enabling accurate oxygen concentration measurement without direct contact between the sensor and the aggressive liquid metal coolant.
3Quantity of substance
If oxygen is supplied as gas or oxides to coolant, then oxidizer concentration increases, but control precision over oxygen injection rate is lost
Solution Approach 1:
The patent employs dynamic control of oxygen injection by continuously adjusting the oxygen supply rate based on real-time coolant oxygen concentration measurements. The system transitions from static oxygen dosing to dynamic modulation, allowing precise control of oxygen injection rates to match varying oxygen consumption conditions in the coolant.
Solution Approach 2:
The patent changes the physical state and delivery method of oxygen from fixed gas/oxide injection to continuously variable controlled dosing. By modifying oxygen delivery parameters (flow rate, injection timing, concentration) based on sensor feedback, the system achieves precise control over the quantity of oxygen added to the coolant.
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 approach ensures efficient and safe operation of nuclear reactor plants by precisely controlling oxygen concentration, reducing corrosion rates, and extending equipment life, enabling safe operation in various modes.
Implementation Method 1
an oxygen sensor in the coolant
Implementation Method 2
a mass-exchange apparatus installed in the coolant which holds solid-phase coolant oxides and is adapted to flowing of coolant through it
Implementation Method 3
a disperser installed partially in the coolant and partially in the near-coolant space and adapted to gas supply from the near-coolant space to the coolant
Implementation Method 4
the rate of oxygen diffusing into the coolant
Implementation Method 5
Oxygen is constantly consumed for oxidation of iron, chrome and other components of construction materials diffusing into coolant
Data Source
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AI summary
The method and system for control of oxygen concentration in the coolant of a reactor plant including a reactor, coolant in the reactor, gas system, mass-exchange apparatus, disperser and an oxygen sensor in the coolant have been disclosed. The method includes the following steps implemented by the system: estimation of the oxygen concentration; comparison of the oxygen concentration with the permissible value; if the oxygen concentration is reduced, comparison of the reduction value and\or rate with the corresponding threshold value; if the reduction value and\or rate of oxygen concentration is below the threshold value, activation of the mass-exchange apparatus; if the reduction value and/or rate of oxygen concentration is above the corresponding threshold value, supply of oxygen-containing gas from the gas system to the near-coolant space and/or activation of the disperser. Technical result: improvement of controllability of oxygen concentration in coolant, enhancement of safety and extension of reactor plant operating life.