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AbstractIn facilities containing tritium, all process equipment is contained in inerted gloveboxes operating at slightly negative pressure relative to the process rooms. The gloveboxes have recirculation systems which include a stripper system. The glovebox stripper systems capture tritium from the glovebox atmosphere to minimize facility emissions with the possibility of recovering the tritium.Hydrogen isotopes released into the gloveboxes are converted to oxide form and removed from the glovebox atmosphere by the glovebox stripper systems – the intended function of these systems. Protiated water (and oxygen) enters the glovebox system in various ways. All water in the gloveboxes is ultimately removed by the stripper system molecular sieve beds which are then processed or disposed of as waste. The water and oxygen enter the glovebox in locations both internal and external to the gloveboxes. The majority of oxygen and water originates external to the gloveboxes in current facility operations.This study evaluated approaches for water source reduction i.e. reducing the amount of water entering the gloveboxes. The second approach explored options to segregate or prevent the mixing of protiated water in the glovebox with the tritiated water formed as part of the tritium oxidation and capture process used to reduce facility emissions.

AbstractRecently, the demand for He-3 has increased dramatically due to widespread use in nuclear nonproliferation, cryogenic, and medical applications. Essentially all of the world’s supply of He-3 is created by the radiolytic decay of tritium. The Savannah River Site Tritium Facilities (SRS-TF) utilizes LANA.75 in the tritium process to store hydrogen isotopes. The vast majority of He-3 “born” from tritium stored in LANA.75 is trapped in the hydride metal matrix. The SRS-TF has multiple LANA.75 tritium storage beds that have been retired from service with significant quantities of He-3 trapped in the metal. To support He-3 recovery, the Savannah River National Laboratory (SRNL) conducted thermogravimetric analysis coupled with mass spectrometry (TGA-MS) on a tritium aged LANA.75 sample. TGA-MS testing was performed in an argon environment. Prior to testing, the sample was isotopically exchanged with deuterium to reduce residual tritium and passivated with air to alleviate pyrophoric concerns associated with handling the material outside of an inert glovebox. Analyses indicated that gas release from this sample was bimodal, with peaks near 220 and 490°C. The first peak consisted of both He-3 and residual hydrogen isotopes, the second was primarily He-3. The bulk of the gas was released by 600 °C.

Palladium finely dispersed in a substrate of kieselguhr (diatomaceous earth) has been successfully used for tritium storage, separation and pumping for a number of years at the Savannah River Site (SRS). Recently SRS has designed and built a new Pd/kieselguhr flow through bed (FTB) prototype for separating tritium from other gases and simultaneously storing the tritium on palladium. The FTB prototype uses single-pass liquid nitrogen for cooling during tritium absorption/loading/storage and electrical heaters for desorption/unloading of tritium. Fourteen (14) hydrogen absorption/desorption or loading/unloading cycles have been conducted with the new FTB prototype. Test results show that all design performance objectives have been successfully achieved: recover >95% of hydrogen gas from feed gas, <5% hydrogen in discharge gas, and >99.9% hydrogen in the desorbed product gas. This paper will discuss the design and operation of the FTB, and results of performance tests such as separation efficiency, hydrogen/tritium storage capacity and temperature profiles during prep cooling, hydrogen loading and unloading.