Periodic Reporting for period 1 - TITANS (Tritium Impact and Transfer in Advanced Nuclear reactorS)
Berichtszeitraum: 2022-09-01 bis 2024-02-29
Operation of fusion devices and future GEN IV reactors will generate or use larger amounts of tritium than existing facilities, therefore safety and social acceptability require to tackle potential permeation through the confinement materials and Tritium release in the environment. Consequences of accidental exposure, whether through dispersion in the environment and integration to the food chain, or directly to the workers or population, are to be understood to be able to propose suitable strategies, for instance developing permeation barrier to minimize tritium permeation at source.
TITANS (Tritium Impact and Transfer in Advanced Nuclear reactorS) is a transdisciplinary project carried out by 21 partners from material sciences, process engineering, biology, dosimetry, environmental sciences and modelling, within the framework of Horizon Europe Euratom research and innovation programme.Tritium as all hydrogen isotopes, is highly mobile in most materials; as a radioactive isotope, strong requirements apply to prevent permeation, dispersion in the environment and exposure of workers and population.TITANS aims at contributing to research and innovation on cross-cutting activities required to improve knowledge on tritium management with a multidisciplinary approach at each step of the tritium life cycle: develop tritium release mitigation strategies, improve waste management and refine knowledge in the field of radiotoxicity, radiobiology and dosimetry. Three scientific work packages address these issues:
- WP1: Proposals for enhancement of barriers against tritium permeation and tritiated waste management
- WP2: Tritium inventory management and modelling
- WP3: Dosimetry, risk assessment and radiation protection following accidental exposure to tritiated dust
Communication and dissemination of the work is of key importance, with a dedicated work-package to spread the knowledge gained to the various scientific communities and train young or new researchers and engineers to the specificities of tritium, most recently via the 3rd Tritium School.
TITANS (Tritium Impact and Transfer in Advanced Nuclear reactorS) is a transdisciplinary project carried out by 21 partners from material sciences, process engineering, biology, dosimetry, environmental sciences and modelling, within the framework of Horizon Europe Euratom research and innovation programme.Tritium as all hydrogen isotopes, is highly mobile in most materials; as a radioactive isotope, strong requirements apply to prevent permeation, dispersion in the environment and exposure of workers and population.TITANS aims at contributing to research and innovation on cross-cutting activities required to improve knowledge on tritium management with a multidisciplinary approach at each step of the tritium life cycle: develop tritium release mitigation strategies, improve waste management and refine knowledge in the field of radiotoxicity, radiobiology and dosimetry. Three scientific work packages address these issues:
- WP1: Proposals for enhancement of barriers against tritium permeation and tritiated waste management
- WP2: Tritium inventory management and modelling
- WP3: Dosimetry, risk assessment and radiation protection following accidental exposure to tritiated dust
Communication and dissemination of the work is of key importance, with a dedicated work-package to spread the knowledge gained to the various scientific communities and train young or new researchers and engineers to the specificities of tritium, most recently via the 3rd Tritium School.
The work carried out on enhancement of barriers against tritium permeation and tritiated waste management on the first half of the project has tackled several tasks, amongst them:
- A new permeation cell was designed to determine permeation rate through stainless steel
- Comparison between Gas Chromatography (GC) and TCAP (Thermal Cycling Absorption Process) systems for hydrogen isotopes separation and water detritiation
- Practical knowledge from decommissioning experience was gained via the SCK CEN and UKAEA collaboration, comparing cutting methods and their applicability
Related “Tritium inventory management and modelling”, a few highlights of the first half of the project are:
- The MAUD autoradiography system provided clear image reconstructions of tritium sources, and was updated to enhance its portability and usability for in-situ applications.
- Local-level detail tritium transport codes, FESTIM, MHIMS and mHIT were applied to various literature cases for validation
On characterizing the impact of exposure to tritium, the first step was to define hydrogen loading protocol for cement and steel particles, and both hydrogen-exposed and tritium-exposed batches were prepared. All studies for this first half focused on hydrogenated particles as a reference for the tritiated ones to come:
- Dry and wet dispersion and deposition study of cement aerosols on vegetables was carried out via a developed method for generating particles containing a tracer that can be used in the environment (fluorescein).
- Bioaccumulation experiments following particles exposure in mussels population showed oxidative DNA damage in digestive gland cells for acute and mid-term chronic exposure.
- To explore tritium particle biokinetics by the skin route, dissolution tests in synthetic sweat solutions, and metal permeation into and through the skin after particles deposition for various concentration and skin condition were carried out. For all metals except Mn and Mb, cells decontaminated using soaps and water presented the higher permeation profile and, for broken skins, the increment of permeation occurred after 8 hours linearly for all metals except for Mn, for which the increase started immediately.
- Genotoxic effects on human macrophages displayed no cytotoxicity impact for steel particles, while cement ones presented a slight cytotoxic effect after 24h at 200 µg/ml. Both types of particles significantly increased loss of chromosomes and chromosomal breakage for all concentrations, but no dose-dependent effect was observed.
- Last but note least, a dosimetric assessment software was developed for reproduction with radiation transport codes, integrating the obtained data on internalization of particles by cells and their position with respect to the nucleus.
- A new permeation cell was designed to determine permeation rate through stainless steel
- Comparison between Gas Chromatography (GC) and TCAP (Thermal Cycling Absorption Process) systems for hydrogen isotopes separation and water detritiation
- Practical knowledge from decommissioning experience was gained via the SCK CEN and UKAEA collaboration, comparing cutting methods and their applicability
Related “Tritium inventory management and modelling”, a few highlights of the first half of the project are:
- The MAUD autoradiography system provided clear image reconstructions of tritium sources, and was updated to enhance its portability and usability for in-situ applications.
- Local-level detail tritium transport codes, FESTIM, MHIMS and mHIT were applied to various literature cases for validation
On characterizing the impact of exposure to tritium, the first step was to define hydrogen loading protocol for cement and steel particles, and both hydrogen-exposed and tritium-exposed batches were prepared. All studies for this first half focused on hydrogenated particles as a reference for the tritiated ones to come:
- Dry and wet dispersion and deposition study of cement aerosols on vegetables was carried out via a developed method for generating particles containing a tracer that can be used in the environment (fluorescein).
- Bioaccumulation experiments following particles exposure in mussels population showed oxidative DNA damage in digestive gland cells for acute and mid-term chronic exposure.
- To explore tritium particle biokinetics by the skin route, dissolution tests in synthetic sweat solutions, and metal permeation into and through the skin after particles deposition for various concentration and skin condition were carried out. For all metals except Mn and Mb, cells decontaminated using soaps and water presented the higher permeation profile and, for broken skins, the increment of permeation occurred after 8 hours linearly for all metals except for Mn, for which the increase started immediately.
- Genotoxic effects on human macrophages displayed no cytotoxicity impact for steel particles, while cement ones presented a slight cytotoxic effect after 24h at 200 µg/ml. Both types of particles significantly increased loss of chromosomes and chromosomal breakage for all concentrations, but no dose-dependent effect was observed.
- Last but note least, a dosimetric assessment software was developed for reproduction with radiation transport codes, integrating the obtained data on internalization of particles by cells and their position with respect to the nucleus.
In addition to permeation barrier, nuclear operators currently rely on trapping systems to minimize release, and most of the tritium is then accumulated as a waste in the form of tritiated water. Developping a tritiated water-processing route to allow the recycling of tritium both minimizes nuclear waste and increases tritium avalaibilty by reusing it, which is highly valuable as it is scarce and potential fuel to nuclear fusion power plants. Another type of nuclear waste is particularly delicate to handle: tritiated metallic dust produced during fusion operation and fusion/fission plant dismantling: adequate conditioning must be conceived to prevent any safety and biological concern during handling and storage.
Decommissioning of nuclear facilities is known to generate fine airborne dust, namely steel and cement aerosols. The presence of tritium in such materials will therefore generate tritiated particles, possibly dispersed in the environment, yet very little studies exist on induced consequences for human/animals/environment contamination.
Decommissioning of nuclear facilities is known to generate fine airborne dust, namely steel and cement aerosols. The presence of tritium in such materials will therefore generate tritiated particles, possibly dispersed in the environment, yet very little studies exist on induced consequences for human/animals/environment contamination.