Hongsuk Chung

Disproportionation Characteristics of a Zirconium-Cobalt Hydride Bed Under ITER Operating Conditions

Abstract Quantitative assessment of a disproportionation in the ZrCo-hydrogen system under ITER-relevant operating conditions was performed by means of experimental tests and a theoretical calculation. In the static temperature experiments with equilibrium hydrogen pressures, a 10% disproportionation of ZrCoHx (x = 2.0 and 2.5) was observed in 5.5 h at 415° (~78 kPa), 9 h at 400° (~72 kPa), 172 h at 380° (~51 kPa), and 1626 h at 350° (~28 kPa). An experimental formula [log τ = 17 268/T (K) - 25.814, where τ is the reaction time (day) of 10% disproportionation] was derived from these experiments. Experiments with a temperature cycling of up to 125 cycles (from room temperature to 350 to 360°) proved that no enhancement of a disproportionation occurs in the ZrCoHx (1.7 < x ≤ 2.0). Typical operation conditions of the ZrCo hydride bed for the D-T gas storage delivery system were proposed based on the ITER FDR 2000 plasma operation scenarios. The disproportionation rate estimated conservatively by the theoretical model indicates that a disproportionation in the ITER basic performance phase can be reduced by <4% even when there is a direct supply from the fuel storage and delivery system beds for all the D-T pulses and by <0.1% when the supply is from the hydrogen isotope separation system.

R&D Activities on the Tritium Storage and Delivery System in Korea

Abstract R&D activities on the tritium storage and delivery system include the development of getter beds to increase tritium recovery and delivery performance, the investigation of tritium reaction characteristics with ZrCo metal-hydride, in-bed calorimetry as tritium measurement techniques, and the development of process design technologies for the storage and delivery system such as pump performance test and bed simulator. The current status of the R&D activities on these subjects is addressed in this paper.

Properties of titanium sponge bed for tritium storage

ABSTRACT A TRF (Tritium Removal Facility) will be constructed at Wolsong Nuclear Generating station to remove the tritium from heavy water. Titanium sponge has been selected as suitable material for tritium product immobilization. This paper is a summary of the experimental results conducted for the various properties of the reaction between titanium sponge and hydrogen isotopes. The conditions for activation, hydriding and dehydriding were investigated. The factors such as initial gas pressure and the helium content in the gas stream influencing the hydriding rate of the bed were examined.

Korea's activities for the development of ITER tritium storage and delivery systems

Abstract The ITER fuel cycle plant is composed of various subsystems such as a long term tritium storage system (LTS), a fuel storage and delivery system (SDS), a tokamak exhaust processing system, a hydrogen isotope separation system, and a tritium plant analytical system. Korea shares in the construction of the ITER fuel cycle plant with the EU, Japan and US, and is responsible for the development and supply of the SDS and LTS. The authors thus present details on the development status of the tritium transport container, the long term tritium storage beds, the short-term delivery system T2, DT, and the D2 storage beds, the calorimetry system, and the associated He-3 recovery loop, the over pressure protection systems, and the gas analysis manifold connected to the tritium plant’s analytical systems.

Adsorption of cobalt(II) ion by titanium-based oxides in high temperature water

Titanium-based adsorbents such as TiO2 and Fe-Ti-O were prepared by hydrolysis of Ti(OC3H7)4 and alkalinizing an equimolar mixed solution of TiCL4 and FeCl2 followed by heat treatment of their hydroxides, respectively. The prepared Fe-Ti-O adsorbent was found to be stable nonstoichiometric ferrous and ferric titanium oxides with pseudobrookite and rutile structures. The Co2+ adsorption characteristics of the adsorbent in high temperature water were investigated in the autoclave.Co2+ adsorption capacity of the Fe-Ti-O adsorbent was determined to be larger man that of TiO2 at high temperatures. The enthalpy changes of 34 and 49 kJ-mol-1 due to the adsorption of Co2+ on the TiO2 and Fe-Ti-O adsorbents indicate that the adsorption is endothermic in the experimental temperature range (15-280 ‡C). From this preliminary study, titanium-based oxides are shown to have good potential applicability for reactor water purification as high temperature adsorption media.

Precipitation characteristics of palladium from a simulated radioactive liquid waste by Ascorbic Acid

The precipitation characteristics of palladium (Pd) from a simulated radwaste solution by ascorbic acid was investigated. Pd was selectively precipitated by the reduction reaction of Pd with ascorbic acid. When the nitric acid concentration in the 8 component system was below 2.0 M, Pd over 99.5 % was selectively precipitated at an ascorbic acid concentration above 0.06 M, while other elements mainly remained in solution. The precipitation yield of Pd by ascorbic acid decreased with the increase of the nitric acid concentration.

Tritium Activities in Korea

ABSTRACT An overview of the tritium related research and activities presently undertaken in Korea is presented. These activities encompass the Wolsong Tritium Removal Facility (WTRF) in KHNP, isotope separation, storage and biology in KAERI, KEPRI and KAIST. The design status of the WTRF that serves four CANDU reactors is described. It is made up of three parts; liquid phase catalytic exchange (LPCE), cryogenic distillation, and metal hydride storage. Results from the technological R&D of tritium processing for the WTRF and biology are summarized.

Key technologies for tritium storage bed development

Abstract ITER Storage and delivery system (SDS) is a complex assembly system. Lots of individual components including tens of storage beds, a few reactors, multiple transfer pumps, vessels, umpteen instruments & sensors which are interconnected with tubing and fittings in a confined glovebox system are to be installed in the given Tritium Plant area. The most important SDS getter bed will be utilized for absorbing and desorbing of hydrogen isotopes in accordance with the fusion fuel cycle scenario. This paper deals with R&D activities on SDS bed design, especially thermal hydraulic analysis in heat loss aspect, the real-time gas analysis in He-3 collection system, and introductory experimental plans using depleted uranium (DU) getter material for storage of hydrogen isotopes, especially of tritium.

Performance of 500kCi Tritium Storage Vessel for WTRF

A prototype TSV (Tritide Storage Vessel) has been manufactured for the long-term storage of tritium of the WTRF (Wolsong Tritium Removal Facility). A performance test was carried out to demonstrate that the TSV could hold a minimum of 500kCi of tritium. This experiment was conducted by a batch type hydriding reaction. Hydrogen gas equivalent to 50kCi of tritium was reacted with the titanium sponge in a batch reaction. Experimental results for 10 batches show that the TSV has enough capacity to store 500kCi of tritium.

Separation of Palladium from a Simulated Radioactive Liquid Waste by Precipitation Using Ascorbic Acid

The separation characteristics of palladium (Pd) from a simulated radwaste solution by ascorbic acid was investigated. Pd was selectively precipitated by the reduction reaction of Pd with ascorbic acid. For a 1-component system with only Pd, over 99.9% Pd was precipitated at ascorbic acid concentrations above 0.025 M. When the nitric acid concentration in a 7-components system (Pd, Rh, Ru, Fe, Mo, Cs, Sr) was below 2.0 M, Pd over 99.5% was selectively precipitated at an ascorbic acid concentration above 0.06 M while the other elements mainly remained in the solution. As the nitric acid concentration in the simulated solution increases, the precipitation yields of Pd decrease. Pd precipitates formed by ascorbic acid were confirmed as Pd metal from XRD analysis results.