Multi-Stage PCCS Condenser with Interstage Catalyst
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current Passive Containment Cooling Systems (PCCS) for nuclear reactors face challenges in effectively managing non-condensable gases like hydrogen and oxygen, which can lead to increased pressure and potential damage during accident scenarios, as they rely on passive recombination methods that are not always efficient.
Innovation Solution
A multi-stage PCCS system is introduced, featuring condensers with interstage catalysts, such as palladium, platinum, or rhodium, to catalytically convert hydrogen and oxygen into steam, reducing the risk of detonation and optimizing heat transfer by using a cross-over conduit system with insulation to manage gas flow and condensation efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If passive recombination methods are used to manage non-condensable gases, then system complexity is reduced, but recombination efficiency is insufficient leading to pressure buildup
Solution Approach 1:
A catalyst (such as platinum, palladium, or rhodium) is introduced as an intermediary substance to facilitate the recombination reaction between hydrogen and oxygen. The catalyst provides an alternative reaction pathway with lower activation energy, enabling efficient recombination without requiring complex external energy input systems, thus maintaining passive operation while significantly improving recombination efficiency
Solution Approach 2:
The catalyst changes the kinetic parameters of the recombination reaction by providing an alternative reaction mechanism. This parameter change enables the reaction to proceed at much higher rates under the existing temperature and pressure conditions in the containment system, resolving the contradiction between simple passive operation and efficient recombination
2Object-affected harmful factors
If hydrogen and oxygen are allowed to accumulate, then heat transfer is simplified, but detonation risk increases
Solution Approach 1:
The catalyst converts the potentially harmful accumulation of hydrogen and oxygen (which could lead to detonation) into a beneficial process by facilitating their controlled recombination into water. This transforms the harmful chemical energy storage into a controlled exothermic reaction that actually helps remove heat from the system while eliminating the detonation risk
3Productivity
If multiple condensing stages are added, then heat removal efficiency is improved, but system complexity increases
Solution Approach 1:
The condensation process is divided into multiple sequential stages, each operating at different temperature and pressure levels. This segmentation allows each stage to be optimized for specific conditions, improving overall heat removal efficiency by capturing heat at multiple points in the thermodynamic process rather than relying on a single condensation event
4Quantity of substance
If catalyst is introduced for recombination, then non-condensable gas concentration is reduced, but system complexity and cost increase
Solution Approach 1:
The catalyst enables the hydrogen and oxygen mixture to self-recombine without requiring external energy input, control systems, or active management. The system essentially serves itself by utilizing the naturally present gases and the catalytic surface to automatically reduce non-condensable gas concentration through the recombination reaction, maintaining simplicity while achieving the desired outcome
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 multi-stage PCCS system effectively reduces the concentration of non-condensable gases, prevents pressure buildup, and enhances heat removal by converting hydrogen and oxygen into steam, thereby improving the safety and efficiency of the cooling process.
Implementation Method 1
A passive containment cooling system (PCCS) for a nuclear reactor is provided. The PCCS includes a first stage condenser, a second stage condenser, and a catalyst in at least one of the first stage outlet header or a second stage inlet header. The catalyst is configured to catalyze a reaction for forming a first gas from a second gas and a third gas in the fluid mixture
Implementation Method 2
The first stage condenser includes a first inlet header, a first outlet header, and a first plurality of channels in fluid communication between the first inlet header and the first outlet header. The first plurality of channels are configured to condense a first condensate portion from a first gas in the fluid mixture
Implementation Method 3
PCCS condensers may include channels (e.g., tubes and/or parallel plates) and may transfer heat to a pool outside of containment and release it to the atmosphere as water vapor, or directly transfer it to the air
Data Source
Figure 1
Figure 2
Figure 3~4A
AI summary
A passive containment cooling system (PCCS) condenser may include a first (SI) and a second stage condenser (S2), which may include channels (104, 114) in fluid communication between an inlet (102, 112) and an outlet header (106, 116). The inlet header (102) of the first stage condenser (SI) may be configured to receive a fluid mixture through a first inlet opening (InOI). The channels (104, 114) may be configured to condense water from the fluid mixture flowing through the channels (104, 114) from the inlet header (102, 112) to the outlet header (106, 116), respectively, of the first (SI) and second stage (S2) condenser. The PCCS condenser may include a catalyst (108) in at least one of the outlet header (106) of the first stage condenser (S 1) or the inlet header (112) of the second stage condenser (S2). The catalyst (108) may catalyze a reaction for forming water from hydrogen and oxygen.