A Prototype Four-Inch Short Hydride (FISH) Bed as a Replacement Tritium Storage Bed

Abstract

The Savannah River Site (SRS) Other bed design improvements are also presented.

Hydriding-Induced Wall Stress Evaluation of a Prototype Four-Inch Short (FISH) Tritium Hydride Bed

“…The Savannah River Site (SRS) Tritium Facilities (TF) have used metal hydride beds to store, separate, transport, compress, and purify hydrogen isotopes for over 20 years. 1,2 The first generation (Gen 1) hydride beds utilize 12.6 kg of LaNi 4.25 Al 0.75 (or LANA.75) and require a hot and cold nitrogen (HCN) system for operation. The second generation (Gen 2) hydride bed uses the same pipe size and LANA.75 alloy as the Gen 1 bed but was developed to thermally swing the bed using electric heaters during desorption and forced atmosphere cooling during absorption.…”

“…The Four-Inch Short (FISH) hydride bed, which is the third generation (Gen 3) of hydride beds, is currently in development and was designed as a direct replacement for the Gen 2 bed. 1 The FISH bed offers the same hydrogen storage capacity as the Gen 2 bed in a shorter bed design (0.61 m) using 4-inch standard schedule pipe, which allows for a smaller glovebox footprint and full-bed-length cartridge heater replacement. Additionally, the FISH bed utilizes the lower pressure LaNi 4.15 Al 0.85 (LANA.85) hydride material, which is expected to improve absorption rates and reduce gas lost during inert evacuation.…”

“…In-Bed Accountability (IBA), and end-of-life bed removal; and facilitating potential He-3 recovery. 1,2 Because metal hydride materials expand upon hydrogen absorption, determining the process vessel (PV) expansion stresses to ensure adequate wall thicknesses is an important aspect of hydride bed development. In 1992, direct wall stress measurements on a prototype hydride SRNL-STI-2016-00198 DRAFT 3 storage bed for the Replacement Tritium Facility (RTF) determined that upon expansion a hydride material will exert force against the PV walls rather than act as a fluid by flowing into the void space to equalize the pressure.…”

“…2 The design and fabrication of the prototype FISH bed have been previously described. 1 The added design features of the FISH bed, including a cellular structure with aluminum heat transfer foam and porous divider plates to partition the hydride material, heater wells, central thermowell, gas inlet filters, IBA U-tube, and external heat transfer fins, may impart unknown stress on the PV walls during hydride absorption/desorption cycling. Therefore, a confirmatory hydriding-induced wall stress evaluation of the prototype FISH bed to ensure the ASME Code compliance of the bed design was performed and is discussed herein.…”

“…For this stepwise absorption, a "step" refers to a partial loading to reach a target H/M value.All bed loadings were determined by pressure-volume-temperature (PVT) calculations. Protium was loaded and unloaded through a gas inlet tube that only penetrates into the first zone/cell of the FISH bed 1. The other gas tube, which runs the full length of the bed, was blanked off during these tests.…”