[en] In the frame of JRC's 1984-87 Fusion Technology Programme and with the aim of contributing to tritium R and D for NET, the commission of the European communities decided in July 1985 the construction on the site of the Ispra establishment of a European tritium handling experimental laboratory (ETHEL). ETHEL is a facility designed to handle a maximum inventory of 100 G tritium and to release annually a maximum of some tenths of curies of tritium. Its commissioning is foreseen for end 1989 beginning 1990. Current practices to be applied for routine management of tritiated wasted generated during the normal ETHEL operations as well as objectives of the experimental research that the JRC staff specifically intend to perform in the field of tritiated waste management strategy and technology are briefly illustrated

[en] This study addresses the issue of partitioning between organically bound and tissue free water tritium (OBT and TFWT consequently) and their modelling in plants subject to chronic releases, with major emphasis on this partitioning validation in field experiments. Under chronic releases, tritium level in plants oscillates between background environmental level and the elevated level when the atmospheric plume is present. Typical long term regulatory models are based on the quasi-equilibrium specific activity paradigm, which produces considerable uncertainty, making the model validation difficult. An alternative approach based on dynamical model describing the processes leading to tritium level oscillations is promising, as it allows for validation of process components and parameters while reducing uncertainty. New formulation of bi-directional tritium exchange under chronic releases is deployed for atmosphere-plant interactions modelling. The proposed robust and simple approach is sensitive to the accuracy of calculated evapotranspiration (ET). To minimize the uncertainty involved, the evapotranspiration and ground heat flux were accounted for using the temperature-based Reference Crop Penman-Monteith formulation (PM). The seasonal delay in the development of the summertime latent heat flux accounted via subsurface temperature in PM was found to be adequate for the Canadian Shield (CRL study site). Measurements of OBT (including OBT night-time formation) conducted in 2008 and 2009 at CRL were used for OBT model calibration. Published results dedicated to experimental quantification of OBT/HTO ratios and datasets collected at CRL in different years were used for OBT model validation. It is found, that notwithstanding enhanced predictive skill of the model (close proximity of model results to observations on a QQ plot), substantial difference from observations exist at high OBT/HTO ratios, which occur shortly after the plume departure. This suggests important contribution from fast-forming labile OBT currently ignored in the model. (author)

[en] Reacting tritiated water with hot metal to recover the tritium from tritiated water has been practiced for considerable time. A metal frequently used for this purpose has been uranium. Recent work at the Tritium Systems Test Assembly at Los Alamos National Laboratory has focused on using magnesium for this purpose. This work was done as part of the Annex IV collaboration between the US Department of Energy/TSTA and the Japan Atomic Energy Research Institute/Tritium Processing Laboratory. Magnesium appears to have reactive properties that are as good as uranium and possibly better, and, of course, magnesium is easier to handle and less strictly controlled. Both bench-scale and practical-scale experiments were conducted with magnesium, including tests with tritiated water. Mg bed construction techniques and operating parameters were determined. Testing showed that the Mg packed bed was very effective for recovering hydrogen isotopes from water. However, when used for this purpose either Mg or U is irreversibly consumed and must be disposed of as tritiated waste. It follows tat this processing technique would be inappropriate for a large tritiated water processing operation. However, this technique may find utility for small-scale systems

[en] The most suitable process for water detritiation is the combined electrolysis catalytic exchange (CECE) process, a combination of electrolysis and catalytic exchange of hydrogen isotopes in a liquid phase catalytic exchange (LPCE) column. Tritium is recovered in gas phase from tritiated water and then injected in the cryogenic distillation system for further enrichment. At the Tritium Laboratory, Karlsruhe (TLK) a CECE facility is running in order to investigate the simultaneous transfer of tritium and deuterium between gas and water. Experiments are performed to determine the height equivalent of theoretical plate (HETP) and the mass transfer coefficients for deuterium and tritium. The purpose of the experiments is to provide the data required for the design of large water detritiation facility for JET and ITER

[en] The chemical processes by which elemental tritium can be converted to tritiated water have been examined by reviewing the available literature on these processes. It would appear that gas phase conversion reactions at room temperature are slow and that they do not contribute significantly to any observed conversion following releases of elemental tritium. The effects of surfaces are not clearly understood. Metals, however, can increase the rate over the gas phase processes, but the magnitude of this increase is not well documented. Further work is necessary to examine the effects of various materials, elevated temperatures, and other parameters on conversion reactions in order to more closely reflect conditions in reactor buildings and other tritium containing facilities

[en] Fusion reactors are our hope for a clean nuclear energy. But as they shall handle huge amounts of tritium, 1.5 10¹⁹ Bq GWth^-1 a^-1 or about 50 000 times more tritium than light water fission reactors, they need detritiation. Most tritium losses can be trapped as or can easily be transformed into tritiated water. Water detritiation is preferably based on the multiplication of the large equilibrium isotope effect during the exchange reaction of tritium between hydrogen gas and liquid water in a counter current trickle bed reactor. Such LPCE (Liquid Phase Catalytic Exchange) requires an efficient hydrophobic catalyst. SCK-CEN invented and developed such a catalyst in the past. In combination with an appropriate packing, different batches of this catalyst performed very well during years of extensive testing, allowing to develop the ELEX process for water detritiation at inland reprocessing plants. The main objectives of this study were to reproduce and possibly improve the SCK-CEN catalyst for tritium exchange between hydrogen and liquid water; and to demonstrate the high overall exchange rate and thus high detritiation factors that can be realized with it in a small and simple LPCE column under typical but conservative operating conditions

[en] Properties of natural and artificial tritium sources are reviewed and the role of tritium in LWR and PWR is analyzed. (author)

[en] Short communication

[en] There have been many significant changes in the status of tritium activities in the US since the 4th Tritium Conference in October, 1991. The replacement Tritium Facility (RTF) at Savannah River Site and the Weapons Engineering Tritium Facility (WETF) at the Los Alamos National Laboratory are now operational with tritium. The Tokamak Fusion Test Reactor (TFTR) has initiated a highly successful experimental campaign studying DT plasmas, and has produced more than 10 Megawatts (MW) of fusion power in a D-T plasma. Sandia National Laboratory has ceased tritium operations at the Tritium Research Laboratory (TRL) and many of the activities previously performed there have been transferred to Los Alamos and Savannah River. The tritium laboratory at Lawrence Livermore National Laboratory has reduced the tritium inventory to <5 grams. The Tritium Systems Test Assembly (TSTA) at Los Alamos continues to be at the forefront of tritium technology and safety development for the fusion energy program

[en] Short communication