Seminarprogramm für 2027
approx January 2027
| Der Forschungsreaktor Saphir: Eine Ära geht zu Ende. Vom Betrieb bis zum geplanten Abriss Sophie Harzmann, Abteilung Strahlenschutz und Sicherheit, PSI Abstract: Zielpublikum für Fortbildung im ENSI-Aufsichtsbereich: Strahlenschutzsachverständige, -techniker und -fachkräfte |
approx Fall 2027 |
The Fundamentals of Tritium Handling and Tritium-Surface Interaction Phenomena Walter T. Shmayda, Tritium Solutions, Inc Abstract: Containment, storage, process monitoring, and scavenging tritium form the basis of all tritium handling systems. This presentation discusses tritium interactions with stainless steel, uranium as a storage medium, tritium monitoring in process loops with ionization chambers, and recovering trace levels of tritium from inert and air-bearing streams for emission reduction. The transport of tritium from the gas phase into stainless steel is a complex process. Tritium decay impacts stainless steel in two distinct ways: energetic electrons fuel radical chemistry on the metal surface and atomic tritium orphaned by a decay provides a unique opportunity for the tritium to attach itself to the surface. Both pathways lead to tritium contamination of the surface and inventory buildup in the metal bulk. Several factors influence the loading rate of getter beds. These include the host medium, the thermal capacity of the containment, and the gas transmission rate from a vessel to the storage device. Uranium is the medium of choice against which the advantages and disadvantages of selecting other storage media need to be assessed. Pyrophoricity is often raised as an issue of concern. Responses to air ingress accident scenarios are benign events in correctly designed storage beds that use depleted uranium. Ionization chambers afford a simple and robust technique for monitoring the movement of tritium in process loops. These devices can be integrated directly into process loops without compromising the leaktightness of the process systems. Ion pair production in these chambers relies uniquely on the concentration of tritons in the carrier stream. However, detailed interpretation of the measurements needs to consider several mitigating factors: operating pressure, type of gas, impurity content, and surface effects. Emission reduction from facilities relies on the extraction of low concentrations of tritium from effluent streams before they are discharged to the environment. This scavenging depends on the composition of the effluent streams. Streams that contain negligible quantities of oxygen are passed through getter beds that have ultra-low hydrogen vapor pressures. Hydrogen containing tritium can be released from the getters and collected for tritium recovery if necessary. Air bearing streams rely on catalytic oxidation traditionally known as ‘burn and dry’ schemes. In these cases, tritium containing species are converted to tritiated water which is collected on driers. Once regenerated, the condensate can be processed for tritium recovery or can be land disposed. Zielpublikum für Fortbildung im ENSI-Aufsichtsbereich: Strahlenschutzsachverständige |