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TRANSversal Actions for Tritium

Periodic Reporting for period 3 - TRANSAT (TRANSversal Actions for Tritium)

Reporting period: 2020-09-01 to 2022-02-28

Tritium is present in fission and fusion reactors and it is already the main radioisotope released in the environment. Strategies have to be elaborated to mitigate tritium sources, to improve the tritiated waste management as well as the knowledge on its radiotoxicity, radiobiology, dosimetry. These are the main goals of TRANSAT.
To limit the tritium sources, TRANSAT has developed new active and passive tritium permeation barriers. It has also worked on in situ treatment of operational effluents. Modelling tools for tritium inventory and tritium permeation fluxes estimation in fusion (ECOSIMPRO) and fission (KUTIM) devices has been benchmarked to improve the level of confidence of their estimations.
Tritium is absorbed/migrates in any material. For tritiated waste, tritium release is related to its inventory/profile in the material. TRANSAT developed innovative measurements to assess both tritium inventory and profile. New concept of confining drums has also been studied to improve tritiated waste storage capabilities.
TRANSAT has also improved the knowledge in the field of radiobiology, dosimetry, radiotoxicology, genotoxicology and ecotoxicology in case of contamination by tritiated dust (steel and cement) that are produced during decommissioning of nuclear facilities. As an example of the outstanding results of TRANSAT, the corresponding committed effective dose coefficient for steel particles, with an activity median aerodynamic diameter of 13.3 µm has been established: it is equal to 3.3 x 10-12 Sv/Bq. This is considered a valuable result for ICPR (International Commission on Radiological Protection) biokinetic models.
One TRANSAT activity is focused on the assessment of the fusion and fission tritium sources and the development of tritium permeation barriers.
After the tritium source evaluation, the development of permeation barriers have been undertaken focused on components of heat exchangers. They permeation efficiency have been tested in tritium rig. Following the assessment of the treatment of the operational tritiated gases generated in fission and fusion, the performance of a membrane reactor for tritiated water decontamination has been established.

In TRANSAT, innovative methods for tritium inventory measurements are developed as new autoradiography technique based on SiPM detectors, Nuclear Reaction Analysis and Laser Induced Breakdown Spectroscopy. They have been successfully tested on tritiated samples.
Modelling tools of the assessment of tritium inventory/migration in reactors or processes are also studied. The comparison of KUTIM and EcosimPro codes has given positive results.

Some studies are aimed at improving knowledge of the environmental consequences of contamination by tritiated products mainly stainless steel and cement ‘inhalable’ particles. Tritiated particles were produced and characterized in term of their physical-chemical stability in biologic media. Different activities have then been undertaken. As an example, the study of the environmental impact of the released tritiated particle by-products using freshwater mesocosms can be mentionned. The biodegradation of particles in the presence of benthic grazers, picoplankton and picobenthos was assessed, as well as the impact on behavioral changes. The results highlighted drastic differences in the ecological niches potentially exposed to tritiated steel or cement particles. Another task concerns rodents that were exposed to tritiated steel particles by intratracheal instillation. The radioactivity was determined in organs and excreta. Specific equivalent and effective dose coefficients were evaluated. Such results are valuable in future revisions of ICRP biokinetic models and dose coefficients for tritium.
Waste management and decommissioning issues surrounding tritium are also tackled. Decommissioning plan for a facility containing NaK and T tritium getters has been proposed with a technical solution that will be implemented.The accuracy of standard measurement techniques for tritium in soft waste was addressed. Later on, the permeability to tritium of proposed waste drum container materials was looking at. A detailed tritium permeation experiment rig was proposed and commissioned.

The project logo, website, templates were developed for the TRANSAT visual identity. Different crucial actions were undertaken for the TRANSAT dissemination. The most important one was the second Tritium School organised in 2021 with 367 registered participants from different countries all over the world. 28 invited speakers presented the main topics being addressed in the TRANSAT project and are the cross-cutting activities related to tritium.

The efficient TRANSAT coordination has insured the managing of contractual and financial issues, the maintain of project management tool and the reporting to the European Commission. Among all the actions, the monitoring of the impact of COVID-19 on TRANSAT, the management of review meeting with external experts and the EU Project Officer, the organization of the consortium meetings and the organization of the TRANSAT ExCom to discuss project progress and outstanding issues must be underlined.
TRANSAT contributes to the solution of a number of key issues in the management of tritium in fission and fusion facilities that will satisfy regulatory requirements and thus minimise environmental and possible subsequent health effects.

Concerning Tritium release mitigation, TRANSAT aims at expanding the body of knowledge in the field of technical solution to mitigate the tritium release. New permeation barrier concepts and effluent detritiation treatments are available at a TRL (~5) that generates trust in the technology and require limited development for industrial scale.
Furthermore, improvement in tritium permeation and inventory modelling in fusion/fission facilities is also a key outcome of the project that will help stakeholders to assess the tritium distribution in their process and thus identify where mitigation systems should be envisaged.

Tritiated waste management faces several issues like tritium mobility and uncertainty in the assessment of tritium inventory. The impact of TRANSAT project will benefit the nuclear waste producer, nuclear waste repositories and nuclear safety authorities.
By developing new confining drums concepts and innovative tritium inventory measurement or assessment methodologies, the TRANSAT project will improve the strategies for safe tritiated waste management at European and International levels.
From TRANSAT project results, recommendations in the field of tritiated waste management will be published that could lead to new regulation policies.

TRANSAT project is expanding the body of knowledge on tritium and to further enhance regulatory oversight of tritium-related activities, especially wherever tritiated particles are expected. TRANSAT project contributes to increase the accuracy of internal dosimetry for tritium and to improve the protection of human health from potential exposures to tritiated materials by means of contribution to preparation of new standards and regulations.
Group Photo at Kick-off Meeting in Brussels