Vortex Driven Passive Hydrogen Recombiner
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Solution Overview
Problem
Conventional hydrogen recombiners and igniters in nuclear reactors face limitations, including reliance on external power, unpredictable combustion behavior, and inefficiencies in large containment volumes, leading to a need for improved passive systems that can effectively manage hydrogen concentrations without deflagration and power failures.
Innovation Solution
A passive hydrogen recombiner and igniter system featuring a horizontal metallic plate coated with a hydrogen recombination catalyst, utilizing swirl vanes to create a vortex for enhanced air flow and igniter activation, and self-sustaining igniter mechanisms like rotating devices for spark generation, allowing for faster hydrogen removal and ignition at lower concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional hydrogen igniters are used to initiate combustion when hydrogen concentration exceeds ignition threshold, then hydrogen is removed by slow deflagration, but there is a risk that deflagration may propagate into more sensitive regions or vent to flammable adjacent volumes and transition to detonation, inducing very high loads to containment structure and equipment
Solution Approach 1:
The patent converts the harmful effect of hydrogen accumulation into a beneficial controlled combustion process by using catalytic recombiners that slowly recombine hydrogen with oxygen to form water, avoiding the risks of deflagration and detonation while still removing hydrogen from the containment atmosphere
Solution Approach 2:
The patent employs catalytic materials that accelerate the oxidation of hydrogen at lower temperatures and concentrations, enabling hydrogen removal through catalytic recombination rather than combustion, thus eliminating the risk of detonation while maintaining effective hydrogen mitigation
2Productivity
If hydrogen igniters are distributed throughout containment to initiate combustion, then hydrogen removal is achieved, but the mixing behavior and type of combustion become unpredictable, fueling the search for alternative methods
Solution Approach 1:
The patent replaces the mechanical/chemical combustion process with a catalytic process that occurs on the surface of catalyst-coated structures, providing predictable and controllable hydrogen recombination without the unpredictability of flame propagation and combustion dynamics
Solution Approach 2:
The patent changes the fundamental parameter of hydrogen removal from combustion-based (unpredictable) to catalysis-based (predictable), operating at lower temperatures and controlled reaction rates that eliminate mixing behavior uncertainties
3Object-affected harmful factors
If catalytic recombiners are used for hydrogen mitigation, then hydrogen recombination occurs without deflagration, but the flow rate of air required for effective operation is relatively high, which natural circulation during LOCA may not provide
Solution Approach 1:
The patent makes the containment structures themselves multi-functional by coating them with catalyst, enabling them to serve both as structural containment and as hydrogen recombination surfaces, thereby utilizing the existing air circulation without requiring additional high flow rates
Solution Approach 2:
The patent enables the containment atmosphere itself to serve the recombination function by using the natural air circulation and hydrogen distribution within containment to provide the necessary reactants and flow conditions for catalytic recombination on the coated surfaces
4Reliability
If pre-inerting is used to generate oxygen-depleted atmosphere in containment, then hydrogen combustion is prevented, but this is practically difficult to apply to large containments
Solution Approach 1:
The patent extracts the oxygen-hydrogen reaction from the bulk atmosphere (as in pre-inerting) and relocates it to controlled catalytic surfaces, allowing hydrogen removal to occur locally at the catalyst-hydrogen interface rather than requiring global atmosphere modification throughout the large containment volume
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 enables faster hydrogen removal and ignition at lower concentrations, reducing the risk of explosive mixtures and enhancing reactor safety by being self-actuating and self-sustaining, independent of external power, with improved mass transfer and heat distribution.
Implementation Method 1
a substantially horizontal, metallic plate having an underside coated with a hydrogen recombination catalyst
Implementation Method 2
a first set of swirl vanes configured to create a vortex out of a second gas traversing the second gaseous intake
Implementation Method 3
a first passive igniter supported proximate the first gaseous intake and a second passive igniter supported proximate the second gaseous outlet
Data Source
AI summary
An igniter apparatus which generates a high speed buoyancy induced vortex to funnel hydrogen and air from the surrounding onto the “igniter core” where an “igniter core” heats up to the auto ignition temperature by the exothermic catalytic oxidation of hydrogen on its surface. Water (vapor) is formed as the product, which inhibits the oxidation reaction, if not stripped away from the catalyst surface. The high velocity of the vortex ensures the stripping of the boundary layer of steam that is formed by the reaction, thus ensuring more active sites are available for hydrogen oxidation. The vortex is formed by channeling an upward draft into a vortex by guided fins. The upward draft is formed by a plate, which is also coated with a hydrogen recombination catalyst. The plate becomes hot by the same catalytic oxidation reaction in the presence of air containing hydrogen.