Contaminated Graphite Decontamination via Thermal Volatilization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The disposal of contaminated graphite, particularly irradiated graphite, is challenging due to the presence of volatile radionuclides like H-3, C-14, and Cl-36, which complicates near-surface storage and increases costs for deep geological disposal, as existing methods fail to reliably prevent radionuclide release.
Innovation Solution
A method involving a base mixture of contaminated graphite and glass, heated to separate volatile radionuclides, followed by compression into a shaped article suitable for storage, which can be embedded in a matrix material to reduce radionuclide content and allow for safer, cost-effective near-surface storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contaminated graphite is stored in deep geological regions, then radionuclide release is prevented, but disposal costs and complexity increase significantly
Solution Approach 1:
The patent applies preliminary action by heating the contaminated graphite before storage to remove volatile radionuclides in advance. This pre-treatment reduces the radionuclide content to below detection limits, allowing the graphite to be stored in simpler near-surface facilities rather than complex deep geological repositories, thus resolving the contradiction between containment reliability and system complexity
Solution Approach 2:
The patent changes the physical-chemical parameters of the graphite by heating it to high temperatures (above 400°C) to volatilize and remove radioactive contaminants. This parameter change transforms the graphite from a high-risk contaminated state to a low-risk cleaned state, enabling simpler storage solutions and reducing disposal complexity while maintaining safety
2Ease of manufacture
If contaminated graphite is heated to separate volatile radionuclides, then near-surface storage becomes possible, but energy consumption increases
Solution Approach 1:
The patent utilizes phase transitions by heating the graphite to convert volatile radionuclides from solid/adsorbed states to gaseous states, allowing them to be removed through heating. This phase change approach efficiently separates contaminants at temperatures above 400°C, making near-surface storage feasible while managing energy consumption through controlled heating processes
Solution Approach 2:
The patent applies extraction by removing volatile radionuclides from the graphite matrix through thermal heating. The radionuclides are extracted in gaseous form and separated from the graphite, which then becomes suitable for near-surface storage. This extraction process reduces energy requirements compared to storing the original contaminated material in complex deep repositories
3Reliability
If volatile radionuclides are present in graphite, then long-lived contamination occurs, but removal through conventional methods is ineffective
Solution Approach 1:
The patent changes the temperature parameter to above 400°C to induce volatilization of radionuclides that cannot be removed by conventional methods at lower temperatures. This parameter change enables the separation of long-lived volatile radionuclides like C-14 and Cl-36 from the graphite matrix, achieving effective decontamination where conventional methods fail
Solution Approach 2:
The patent utilizes phase transitions by heating the graphite to high temperatures where volatile radionuclides transition from bound states in the graphite matrix to gaseous states. This phase change enables effective removal of persistent contaminants through thermal desorption and volatilization, achieving decontamination that conventional low-temperature methods cannot accomplish
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 method significantly reduces volatile radionuclide content in graphite, enabling safe storage over geological periods with reduced safety requirements, allowing for near-surface disposal and minimizing the need for deep underground storage, thus lowering disposal costs and complexities.
Implementation Method 1
Heating a base mixture comprising contaminated graphite and at least one glass for separating volatile radionuclides from the contaminated graphite
Implementation Method 2
separating volatile radionuclides from the contaminated graphite
Implementation Method 3
compressing the treated graphite to obtain a shaped article which is suitable for final storage
Data Source
AI summary
The present invention relates to the decontamination of contaminated graphite, in particular of irradiated graphite. According to the invention, this is understood as meaning a method for separating volatile radionuclides from contaminated graphite and transforming the graphite together with non-volatile radionuclides into a form appropriate for ultimate storage. The method according to the invention comprises heating up the contaminated graphite to obtain treated graphite, compacting the treated graphite to obtain a formed piece and optionally embedding the treated graphite in a matrix material to obtain an encapsulated formed piece. Depending on the requirements specific to the country concerned, disposal and storage of the formed piece comprising the treated graphite is possible with less demanding safety requirements. As a result, the volume of such material that requires particularly sophisticated and consequently particularly cost-intensive disposal and storage, particularly storage deep underground, can be reduced significantly. This also leads to significantly reduced costs for the disposal of contaminated graphite, large quantities of which occur on an annual basis.