Post-Accident Fission Product Removal System

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Solution Overview

Problem

Post-nuclear accident scenarios pose a risk of hydrogen combustion and explosion due to hydrogen production from damaged nuclear fuel, and venting to reduce this risk can release harmful fission products into the environment, necessitating an effective method to remove radioactive products from air.

Innovation Solution

A post-accident fission product removal system comprising an air mover connected to a filter assembly with a centrifugal separator, charcoal filter, and HEPA filter, followed by an ionization chamber with charged plates to capture radioisotopes from filtered air, and optionally a laser separator to separate isotopes by mass.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If venting is used to reduce hydrogen concentration and explosion risk, then safety against hydrogen explosion is improved, but harmful fission products are released to the environment

Engineering Contradiction:
Improveexplosion risk reductionVSAvoidfission product release
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent introduces an intermediary system (filter assembly with HEPA filters and ionization chamber) between the venting process and the environment. This intermediary captures radioisotopes from the vented air through filtration and electrostatic precipitation, allowing hydrogen to be safely vented while preventing fission products from reaching the environment.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent extracts harmful radioisotopes from the vented air stream using the filter assembly and ionization chamber. By separating and removing these harmful components while allowing the bulk gas (hydrogen and air) to pass through, the system resolves the contradiction between venting for safety and preventing radioactive release.

Inventive Principle:
Principle #2Taking out (Extraction)

2Object-generated harmful factors

If filtration is used to remove radioisotopes from air, then environmental contamination is reduced, but system complexity increases due to multiple filter components

Engineering Contradiction:
Improveenvironmental contaminationVSAvoidsystem structure
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent combines multiple filtration functions into a single integrated filter assembly that includes centrifugal separator, HEPA filters, and an ionization chamber with electrostatic precipitator. This merging of mechanical filtration and electrostatic precipitation into one unit reduces overall system complexity while maintaining high removal efficiency for radioisotopes.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The filter assembly uses composite structural design combining different filtration mechanisms (mechanical filtration media and electrostatic charging components) within a single integrated unit. This composite approach achieves superior radioisotope removal while simplifying the overall system architecture compared to separate standalone units.

Inventive Principle:
Principle #40Composite materials

3Measurement precision

If ionization chamber is used to capture radioisotopes, then capture efficiency is improved, but energy consumption increases due to charging electrodes

Engineering Contradiction:
Improveradioisotope capture efficiencyVSAvoidelectrode energy consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The ionization chamber applies partial ionization action by using charged plates to create an electric field that selectively captures only the radioisotopes that become ionized, rather than requiring complete ionization of all air molecules. This partial action achieves high capture efficiency for the target contaminants while minimizing energy consumption compared to full ionization approaches.

Inventive Principle:
Principle #16Partial or excessive action

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 effectively filters and ionizes contaminated air to capture radioisotopes, reducing the risk of explosions and environmental contamination by producing clean air while allowing for safe handling and decay of captured isotopes.

Implementation Method 1

a centrifugal separator configured to receive the contaminated air and to initially separate out larger-sized debris from the contaminated air

Methodology Applied
Scientific EffectCentrifugal separation: Centrifugal Separation

Implementation Method 2

a charcoal filter connected to the centrifugal separator, the charcoal filter including activated carbon, the charcoal filter configured to receive the centrifuged air and to remove gases with an affinity to the activated carbon

Methodology Applied
Scientific EffectAdsorption: Adsorption

Implementation Method 3

a high-efficiency particulate air filter connected to the charcoal filter, the high-efficiency particulate air filter configured to receive the carbon-filtered air and to remove smaller particulates missed by the charcoal filter

Methodology Applied
Scientific EffectPhysical filtration: Filter (physical)

Implementation Method 4

an ionization chamber connected to the filter assembly, the ionization chamber including an anode and a cathode, the ionization chamber configured to receive the filtered air from the filter assembly and to ionize and capture radioisotopes from the filtered air

Methodology Applied
Scientific EffectIonization: Ionisation

Implementation Method 5

ionizing the filtered air to facilitate the electrostatic capture of the radioisotopes

Methodology Applied
Scientific EffectElectrostatic capture: Electrostatics

Data Source

PatentEP3627519B1Post-accident fission products removal system and method of removing post-accident fission products
Publication Date: 2023.05.17 GE HITACHI NUCLEAR ENERGY AMERICAS LLC
  • EP3627519B1 patent drawingFigure 1
  • EP3627519B1 patent drawingFigure 2
  • EP3627519B1 patent drawingFigure 3

AI summary

A post-accident fission product removal system (100) may include an air mover (104), a filter assembly (106), and/or an ionization chamber (116). The air mover (104) may be configured to move contaminated air (102) through the filter assembly (106) to produce filtered air (115). The ionization chamber (116) may be connected to the filter assembly (106). The ionization chamber (116) may include an anode (118) and a cathode (120). The ionization chamber (116) may be configured to receive the filtered air (115) from the filter assembly (106) and to ionize and capture radioisotopes from the filtered air (115) to produce clean air (124).