• Nuclear Engineering and Technology
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• 제35권6호
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• pp.515-522
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• 2003

Tritium behavior in the solid breeder blanket is one of the key factors in determining tritium self-sufficiency, as well as safety, of fusion reactors. Recently, a model has been developed to describe the tritium behavior in solid breeder material, which can predict the tritium release and inventory in the blanket. However, the model has limitation to account for tritium solubility effects, mainly existing as LiOT, especially inside the $Li_{2}O$ solid breeder. In order to improve the capability of predicting the LiOT precipitation in $Li_{2}O$ solid breeder, a new logic is developed and integrated in the existing tritium release and inventory calculation code. With the logic developed in this work, the code can have capabilities to analyze tritium release and inventories in $Li_{2}O$ under steady and transient conditions. It can be found that tritium inventory as LiOT is an important mechanism under pulsed operation, and the amount of inventory becomes higher as the tritium generation rate increases and the temperature decreases. Also, the temperature limits for the generation of LiOT precipitation are determined. Therefore the developed logic helps understand the tritium transport mechanism in $Li_{2}O$ solid breeder.

• Nuclear Engineering and Technology
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• 제41권5호
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• pp.729-738
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• 2009

Given the evolution of High-Temperature Gas-cooled Reactor(HTGR) designs, the source terms for licensing must be developed. There are three potential source terms: fission products, actinides in the fuel and tritium in the coolant. It is necessary to provide first an inventory of the source terms under normal operations. An analysis of source terms has yet to be performed for HTGRs. The previous code, which can estimate the inventory of the source terms for LWRs, cannot be used for HTGRs because the general data of a typical neutron cross-section and flux has not been developed. Thus, this paper uses a combination of the MCNP, ORIGEN, and MONTETEBURNS codes for an estimation of the source terms. A method in which the HTR-10 core is constructed using the unit lattice of a body-centered cubic is developed for core modeling. Based on this modeling method by MCNP, the generation of fission products, actinides and tritium with an increase in the burnup ratio is simulated. The model developed by MCNP appears feasible through a comparison with models developed in previous studies. Continuous fuel management is divided into five periods for the feeding and discharging of fuel pebbles. This discrete fuel management scheme is employed using the MONTEBURNS code. Finally, the work is investigated for 22 isotope fission products of nuclides, 22 actinides in the core, and tritium in the coolant. The activities are mainly distributed within the range of $10^{15}{\sim}10^{17}$ Bq in the equilibrium core of HTR-10. The results appear to be highly probable, and they would be informative when the spent fuel of HTGRs is taken into account. The tritium inventory in the primary coolant is also taken into account without a helium purification system. This article can lay a foundation for future work on analyses of source terms as a platform for safety assessment in HTGRs.

• 한국수소및신에너지학회논문집
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• 제23권1호
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• pp.49-55
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• 2012

Hydrogen isotopes accountancy and storage are important functions in a nuclear fusion fuel cycle. The hydrogen isotopes are safely stored in metal hydride beds. The tritium inventory of the bed is determined from the decay heat of tritium. The decay heat is measured by circulating helium through the metal hydride bed and measuring the resultant temperature increase of the helium flow. We are reporting our preliminary experimental results on the hydrogen isotopes accountancy and storage performance in a metal hydride bed.

• 품질경영학회지
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• 제19권2호
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• pp.96-107
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• 1991

At the design stage of a plant, the plausible causes and pathways of release of hazardous materials are not clearly known. Thus there exist large amount of uncertainties on the consequences resulting from the operation of a fusion plant. In order to better handle such uncertain circumstances, we utilize the Probabilistic Risk Assessment(PRA) for the safety analyses on fusion power plant. In this paper, we concentrate on the tritium release accident. We develop a simple model that describes the process and flow of tritium, by which we figure out the locations of tritium inventory and their vulnerability. We construct event tree models that lead to various levels of tritium release from abnormal initiating events. Branch parameters on the event tree are assessed from the fault tree analysis. Based on the event tree models we construct influence diagram models which are more useful for the parameter updating and analysis. We briefly discuss the parameter updating scheme, and finally develop the methodology to obtain the predictive distribution of consequences resulting from the operating a fusion power plant. We also discuss the way to utilize the results of testing on sub-systems to reduce the uncertain ties on over all system.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2003년도 가을 학술논문집
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• pp.117-123
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• 2003

지난 논문에 이어서 삼중수소 취급시설의 일부인 삼중수소 주입계통과 재생계통을 소개하였다. 두 계통은 모두 삼중수소의 유출이 가능한 계통들로서 GB안에 설치되어야 하는 계통들이다. 삼중수소 주입계통은 삼중수소 취급시설을 사용하여 목적하는 제품을 생산하게 되는 주 계통으로서 삼중수소의 관리를 위하여 정확히 삼중수소의 주입/분배량을 계량할 수 있어야 하고, 주입 후 계통내 잔여 삼중수소를 최대한 회수할 수 있도록 하여 방사성 물질의 환경방출을 최소화 할 뿐만 아니라 귀한 자원의 손실을 최소화하도록 설계되었다. MS, Ni catalyst bed, metal getter 등 재생이 필요한 TRS 내부의 장치들은 별도의 재생계통을 사용하여 재생한다. 다른 장치들의 재생은 장치를 가열하면서 적절한 purge gas를 흘려주는 비교적 간단한 방법으로 재생이 가능하나 삼중수소를 흡착한 metal getter의 삼중수소를 회수해야 하기 때문에 복잡한 공정을 거쳐야 한다.

• 한국수소및신에너지학회논문집
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• 제23권1호
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• pp.56-64
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• 2012

The ITER fuel cycle is designed for DT operation in equimolar ratio. It involves not only a group of fuelling system and torus cryo-pumping system of the exhaust gases through the divertor from the torus in tokamak plant, but also from the exhaust gas processing of the fusion effluent gas mixture connected to the hydrogen isotope separation in cryogenic distillation to the final safe storage & delivery of the hydrogen isotopes in tritium plant. Tritium plant system supplies deuterium and tritium from external sources and treats all tritiated fluids in ITER operation. Every operation and affairs is focused on the tritium inventory accountancy and the confinement. This paper describes the major fuel cycle processes and interfaces in the tritium plant in aspects of upcoming technologies for future hydrogen and/or hydrogen isotope utilization.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2017년도 추계학술논문요약집
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• pp.323-324
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• 2017

• 품질경영학회지
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• 제26권1호
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• pp.201-212
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• 1998

A methodology of the safety analysis on the fusion power plant is introduced. It starts with the understanding of the physics and engineering of the plant followed by the assessment of the tritium inventory and flow rate. We a, pp.y the probabilistic risk assessment. An event tree that explains the propagation of the accident is constructed and then it is translated in to an influence diagram, that is accident is constructed and then it is translated in to an influence diagram, that is statistically equivalent so far as the parameter updating is concerned. We follow the Bayesian a, pp.oach where model parameters are treated as random variables. We briefly discuss the parameter updating scheme, and finally develop the methodology to obtain the predictive distribution of time to next severe accident.