Daeseo Koo

ITER storage and delivery system R&D in Korea

Korea is supposed to develop the ITER tritium storage and delivery system (SDS), which is one of the main components of the ITER tritium plant. For successful procurement, there are several ongoing R&D activities in the detailed design phase. Investigation of design parameters of the storage and delivery beds has been performed. Small and large-scale mock-ups of ZrCo beds are used to test the capability of desirable rapid delivery and recovery performance and to establish the pertinent procedure of in-bed calorimetry. An experimental apparatus is prepared to develop the integration and verification technologies for the unit processes of the tritium SDS. The performance test of a tritium-compatible metal bellows pump is examined, and the results show a reasonable agreement with the catalog data of the pump. A tritium storage and delivery bed simulator has been developed to simulate various bed operation scenarios under normal and abnormal conditions. A prototype of the SDS simulator is fabricated, and the bed operation scenario generation program to be applied to this simulator is developed. The design requirement of the tritium loading station (TLS) calorimeter is prepared based on a benchmarking mock-up calorimeter, namely, Korea Electric Power Research Institute Tritium Laboratory (KEPTL) calorimeter. Documents for the procurement of the TLS calorimeter will be developed through the experience on the KEPTL calorimeter operation.

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.

Safety Analysis of a Hydrogen Isotopes Process

A nuclear fusion fuel cycle plant is composed of various subsystems such as a hydrogen isotope storage and delivery system, a tokamak exhaust processing system, and a hydrogen isotope separation system. Korea shares in the construction of the International Thermonuclear Experimental Reactor fuel cycle plant with the EU, Japan and US, and is responsible for the development and supply of the storage and delivery system. We thus present details on the hydrogen isotope process safety. The main safety analysis procedure is to use a hazard and operability study. Nine segments were studied how the plant might deviate from its design purpose. We present a detailed description of the process, examine every part of it to determine how deviations from the design intent can occur and decide whether these deviations can give rise to hazards. We determine possible causes and note protective systems, evaluate the consequences of the deviation, and recommend actions to achieve our safety goal.

Hydriding Performances and Modeling of a Small-Scale ZrCo Bed

Abstract Korea has been developing nuclear fusion fuel storage and delivery system (SDS) technologies including a basic scientific study on hydrogen storage. To develop nuclear fusion technology, it will be necessary to store and supply hydrogen isotopes needed for Tokamak operation. SDS is used for storing hydrogen isotopes as a metal hydride form. We designed and fabricated a small-scale getter bed of zirconium cobalt (ZrCo). The rapid hydriding of tritium is very important not only for safety reasons but also for the economic design and operation of the SDS. The effect of the initial absorption temperatures on the hydriding of ZrCo was measured and analyzed. The experimental results of the hydrogen pressure of hydriding (ZrCoH2.8) at various cooling temperatures are in agreement with the calculated values using numerical modeling equations. The effect of a helium blanket on hydriding was measured and analyzed. The experimental results of the hydriding with 0 %, 4%, and 8% of helium concentration are in agreement with the calculated values based on numerical modeling equations.

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.

Rapid Cooling Performance Evaluation of a ZrCo bed for a Hydrogen Isotope Storage

Abstract >> The nuclear fuel cycle plant is composed of various subsystems such as a fuel storage and deliverysystem (SDS), a tokamak exhaust processing system, a hydrogen isotope separation system, and a tritium plantanalytical system. Korea is sharing in the construction of the International Thermonuclear Experimental Reactor(ITER) fuel cycle plant with the EU, Japan ,and the US, and is responsible for the development and supply ofthe SDS. Hydrogen isotopes are the main fuel for nuclear fusion reactors. Metal hydrides offer a safe and convenientmethod for hydrogen isotope storage. The storage of hydrogen isotopes is carried out by absorption and desorptionin a metal hydride bed. These reactions require heat removal and supply respectively. Accordingly, the rapid storageand delivery of hydrogen isotopes are enabled by a rapid cooling and heating of the metal hydride bed. In thisstudy, we designed and manufactured a vertical-type hydrogen isotope storage bed, which is used to enhance the cooling performance. We present the experimental details of the cooling performances of the bed using variouscooling parameters. We also present the modeling results to estimate the heat transport phenomena. We comparedthe cooling performance of the bed by testing different cooling modes, such as an isolation mode, a natural convection mode, and an outer jacket helium circulation mode. We found that helium circulation mode is the mosteffective which was confirmed in our model calculations. Thus we can expect a more efficient bed design byemploying a forced helium circulation method for new beds.Key words : Nuclear fusion energy(핵융합), Storage and delivery bed(수소저장용기), Hydrogen isotope(수소동위원소), Metal hydride(금속수소화물), Zirconium cobalt(지르코늄 코발트)

Hydrogen Absorption/Desorption and Heat Transfer Modeling in a Concentric Horizontal ZrCo Bed

Long-term global energy-demand growth is expected to increase driven by strong energy-demand growth from developing countries. Fusion power offers the prospect of an almost inexhaustible source of energy for future generations, even though it also presents so far insurmountable scientific and engineering challenges. One of the challenges is safe handling of hydrogen isotopes. Metal hydrides such as depleted uranium hydride or ZrCo hydride are used as a storage medium for hydrogen isotopes reversibly. The metal hydrides bind with hydrogen very strongly. In this paper, we carried out a modeling and simulation work for absorption/desorption of hydrogen by ZrCo in a horizontal annulus cylinder bed. A comprehensive mathematical description of a metal hydride hydrogen storage vessel was developed. This model was calibrated against experimental data obtained from our experimental system containing ZrCo metal hydride. The model was capable of predicting the performance of the bed for not only both the storage and delivery processes but also heat transfer operations. This model should thus be very useful for the design and development of the next generation of metal hydride hydrogen isotope storage systems.

Dehydriding Performance in a Depleted Uranium Bed

4 KAERI, 989-111 Daedeokdaero, Yuseong, Daejeon, 34057, Korea Abstract >> It is necessary to store and supply hydrogen isotopes for Tokamak operation. A storage and delivery system (SDS) is used for storing hydrogen isotopes as a metal hydride form. We designed and fabricated a depleted uranium (DU) bed to store hydrogen isotopes. The rapid storage of hydrogen isotopes is very important not only for safety reasons but also for the economic design and operation of the SDS. The delivery rate at the desorption temperatures without the operation of a dry pump was analyzed in comparison with that with the operation of the dry pump. The effect of the initial desorption temperatures on the dehydriding of the DU without the operation of the dry pump was measured. The effect of the initial desorption temperatures on the dehydriding of DU with the operation of the dry pump was also measured and analyzed. The primary pressure on the desorption temperatures without the operation of the dry pump was analyzed in comparison with that with the operation of the dry pump. The temperature gradient of the coil heater and the primary vessel was also analyzed. Our results will be used to develop pilot scale hydrogen isotope processes. It was confirmed that dehydriding of a medium-scale DU bed has enabled without the operation of the dry pump.

Dehydriding performances of a medium-scale DU bed

It will be necessary to store and supply hydrogen isotopes needed for Tokamak operation. A storage and delivery system (SDS) is used for storing hydrogen isotopes as a metal hydride form. We designed and fabricated a medium-scale getter bed of depleted uranium (DU). The rapid hydriding of tritium is very important not only for safety reasons but also for the economic design and operation of the SDS. The delivery rate at the desorption temperatures without the operation of a dry pump was analyzed in comparison with that with the operation of the dry pump. The effect of the initial desorption temperatures on the dehydriding of the DU without the operation of the dry pump was measured and analyzed. The effect of the initial desorption temperatures on the dehydriding of DU with the operation of the dry pump was also measured and analyzed. The primary pressure on the desorption temperatures without the operation of the dry pump was analyzed in comparison with that with the operation of the dry pump. The temperature gradient of the coil heater and the primary vessel was also analyzed.

Development of Tritium Technologies at KAERI

Abstract Tritium is formed by neutrons captured from deuterium. If left to accumulate, tritium oxide will become a hazard to the operating staff and public. The primary purpose of a Tritium Removal Facility (TRF) is to reduce tritium concentration in a heavy water moderator. In Korea, operation of a TRF commenced at the Wolsong Nuclear Power Site on July 26th, 2007. Nowadays, KAERI is developing a Very High Temperature Gas Cooled Reactor (VHTR). We have developed a tritium behavior analysis code for the VHTR. We also developed analytical methods for the measurement of food stuffs. Korea shared in the construction of the ITER fuel cycle plant with the EU, Japan, and the US, and is responsible for the supply of an SDS (Tritium Storage and Delivery System). We present the recent progress in the development of tritium storage technology, and safety features of the related system. KAERI has been developing tritium technologies related to the Wolsong TRF, HANARO, VHTR, and nuclear fusion fuel systems. We thus present details on the recent development progress of these tritium systems.