Search

Ion implantation driven permeation (IDP) behavior on pure molybdenum has been investigated using deuterium ion with low energy (200–2000 eV). The experimental results include measurements of the de...

A computer-based Expert Adviser has been developed to catalog technical expertise and dispense this knowledge to operators of a complex system of distillation columns at the Los Alamos National Laboratory (LANL). The Expert Adviser is also used to train personnel in operation of the LANL Tritium Systems Test Assembly (TSTA) Isotope Separations System (ISS). The methodology is applicable to a wide range of operations where documentation and transfer of knowledge is desirable.

Experimental study for separation of hydrogen isotopes has been performed by using a ‘cryogenic-wall’ thermal diffusion column. The separation experiments were carried out with H-D system under total reflux and continuous feed operation mode. The dependence of the separation factor on the column pressure were examined for both experiments. In the total reflux experiments, the maximum separation factor of the ‘cryogenic-wall’ column was about 12.4 times larger than for the ‘water cooled-wall’. The effect of the feed flow rate on the separation factor and on the optimum pressure was examined in the continuous feed experiments. As the feed flow rate increased, the separation factor decrease appreciably, and the optimum pressure shift progressively to higher region.

This paper reports on dynamic behavior of cryogenic distillation columns which has been studied with a H-D-T system (1.5 g of tritium) under single column and two-column cascade operation modes. The columns used were different in inner diameters (1 cm and 2 cm) and in size packings (3 mm Dixon rings for the larger column and 1.5 mm Dixon rings for the smaller column). For both of the columns, the experimental observations for composition distribution at the steady-state was in close agreement with calculated results of all the components. The HETP values measured were in the range from 3 to 6 cm. The dynamic variations of compositions in bottom product streams experimentally observed were well predicted by computer-aided simulation. For top product streams, the variations were significantly slow in comparison with those of the calculated results using an assumption that liquid holdups in condensers were negligible. These results indicate holdups at the condensers.

This paper reports that to study application o laser Raman spectroscopy for fusion fuel gas analysis by an in situ method, methane (CH{sub 4}) and tritium (T{sub 2}) mixed gases were measured. In the mixed gases, hydrogen isotope exchange reactions were induced by beta decay, and various isotopic hydrogens and methanes were produced. Spectral peaks of {nu}{sub 1} and {nu}{sub 3} bands were detected individually for CH{sub 4} and four tritiated methanes. The {nu}{sub 1} bands between 1700-1900 cm{sup {minus}1} were selected as suitable ones for quantitative analysis. After mixing T{sub 2} and CH{sub 4} gases, while large amounts of tritiated methanes were produced as time lapsed, the equilibrium state was not reached by the time 1000 h had passed. It was presumed that the isotope exchange reactions were very slow compared to mixed gases of just hydrogen isotopes.

The R and D for tritium technology and studies of tritium science in Japan has been carried out in the national institutions (JAERI, PNC and others), in the universities, and in industry. In fusion fuel technology, the technological R and D of tritium processing and handling has been carried out by TPL-JAERI, including collaboration with TSTA (United States) and basic and innovative research conducted by the universities. PNC has conducted R and D and engineering studies in the heavy water quality control system for FUGEN reactor, a heavy water cooled reactor ATR, and in the tritium recovery system for the heavy water coolant. Since the last meeting in Toronto, there are many developments in the above researches which will be summarized in this paper with some results.

A polyimide membrane has a selective permeability for hydrogen gas and water vapor. A small scale experimental apparatus for reducing the tritium concentration of air was designed and fabricated at...

Laser Raman spectroscopy has been applied to the on-line analysis of the operation of the cryogenic Isotope Separation System (ISS) at the Tritium Systems Test Assembly (TSTA). A flow-through cell was employed to permit near real-time observation of the dynamic response of the 3-column ISS. Accurate analysis of hydrogen isotopic mixtures may be made in less than 2 minutes. Full response to a change in the sampling point is achieved in approximately one minute. In this paper, response measurements are shown as well as static column profiles and dynamic response to induced parameter changes. Cross check of analysis was performed with radio-gas chromatography.

The recent results of the Isotope Separation System (ISS) operations at the Tritium Systems Test Assembly (TSTA) with 100 g of tritium indicate that the system generally satisfies design goals, while system stability problems remain to be solved. In this paper, the authors configure the ISS system for the three column mode. which is one of the promising cascade configurations in a fusion fuel cycle, to eliminate such instability and operated it for six days. Fluctuations in flows and liquid levels were improved. Column separation characteristics obtained were satisfactory and agreed with the numerical analysis. The amount of discharged tritium was an acceptable effluent level. This means that the existing ISS system can be used as a three column system and possibly be applied to numerous fuel concepts. Presently, a new laser Raman spectroscopic gas analyzer has been installed at the ISS. This on-line system enables studies of the ISS dynamic behavior for further stability and performance data.

This paper reports the preliminary results of studies of the kinetics of the reactions of T2 with H2, D2, and CH4. The gas phase reactions were studied using laser Raman spectroscopy for the real-t...

This paper reports that the United States Department of Energy (USDOE) and the Japan Atomic Energy Research Institute (JAERI) have installed a full-sale fuel cleanup system (JFCU) for testing at Los Alamos. The JFCU was designed by JAERI and built by Mitsubishi Heavy Industries (MHI) in Kobe, Japan. Experience gained by Japanese working at Los Alamos facilitated development of a system consistent with Los Alamos operations and standards. US or equivalent Japanese standards were generally used for design resulting in minor problems at electrical interfaces. Frequent written interchanges were essential to project success, as spoken communications can be misunderstood. Differing work styles required detailed pre-planning, separation of responsibilities, and daily scheduling meetings. Safety and operational documentation drafted by JAERI personnel was revised at Los Alamos to assure conformance with USDOE and Los Alamos standards. The project was successful because both Japanese and American participants worked hard to overcome potential problems. These experiences will be valuable in conducting future international fusion projects.

In this paper experimental study for separation of hydrogen isotopes has been performed by using a cryogenic-wall thermal diffusion column refrigerated by liquid nitrogen. The column separated H-D system at total reflux and total recycle operational modes. The dependences of the separation factor on the column pressure and hot wire temperature were examined for the total reflux experiments. The optimum pressure observed was 30 kPa at 1273 K. The maximum separation factor at 473 K was larger than that at 1273 K since HD molecules were not produced on the hot wire by the isotope exchange reaction. The separation factor was exponentially proportion al to the hot wire temperature. In the total recycle experiments, the separation factor was measured under a variety of flow rates, positions and compositions of the feed stream. The increase in the feed flow rate deteriorated the separation factor appreciably.

In order to discuss the long-term reliability and safety of zirconium-cobalt alloy for tritium use, the release behavior of decay helium from ZrCo tritide has been investigated for one and a half years with a radio-gaschromatograph. In this paper, the results show that the release fractions of the total decay {sup 3}He in ZrCo tritide are less than 3% and has been almost constant for 18 months under the following conditions: the operating temperatures = 293 {approximately} 523 K, the atom ratios (T/ZrCo) = 0.3 {approximately} 1.4, and the number of hydrogenation-dehydrogenation cycles before tritiation = 1 {approximately} 10. Moreover, residual decay {sup 3}He was not released even if ZrCo was heated to 873 K, though most of the tritium was released. It became clear that the decay {sup 3}He was quite immovable in ZrCo tritide under these experimental conditions.

This paper reports on cryogenic distillation experiments that have been performed with an H- D-T system (1.5 g of tritium) by using two columns with different inner diameters (1 and 2 cm) and different size packings (a 3-mm Dixon ring for the larger column and a 1.5- mm Dixon ring for the smaller column). The height equivalent to a theoretical plate (HETP) values measured during total reflux operation ranged from 4 to 6 cm for both columns and showed no apparent dependence on vapor velocities. The HETP values under total recycle operation, which varied from 3 to 6 cm, gradually decreased with increasing reflux ratios. The feed flow rates also had influenced the HETP. Consequently, the HETP values were correlated by the flow rates of the feed and vapor streams of the column and by the reflux ratio.

The Tritium Process Laboratory (TPL) at the Japan Atomic Energy Research Institute (JAERI) has developed a Fuel Cleanup System (FCU) which accepts simulated fusion reactor exhaust and produces pure hydrogen isotopes and tritium-free waste. The major components are; a palladium diffuser, a catalytic reactor, cold traps, a ceramic electrolysis cell, and zirconium-cobalt beds. In 1988, an integrated FCU process loop was installed in the TPL. A number of “hot” runs were performed to study the system characteristics and improve performance. Under the US-Japan collaboration program, the “JAERI Fuel Cleanup System” (JFCU) was designed and fabricated by JAERI/TPL for testing at the Tritium Systems Test Assembly (TSTA) in Los Alamos National Laboratory as a major subsystem of the simulated fusion fuel cycle. The JFCU was installed in the TSTA in early 1990.

An experiment on the separation of hydrogen isotopes has been carried out by using a thermal diffusion column with a “cryogenic-wall” cooled by liquid nitrogen. The separation factor was compared w...

Implantation-driven permeation (IDP) behavior of deuterium implanted with low energy (100–1800 eV) into 304 stainless steel has been studied. The experimental results showed that steady state perme...

Under a collaborative agreement between US and Japan, two tritium processing components, a palladium diffuser and a ceramic electrolysis cell have been tested with tritium for application to a Fuel Cleanup System (FCU) for plasma exhaust processing at the Los Alamos National Laboratory. The fundamental characteristics, compatibility with tritium, impurities effects with tritium, and long-term behavior of the components, were studied over a three year period. Based on these studies, an integrated process loop, JAERI Fuel Cleanup System'' equipped with above components was installed at the TSTA for full scale demonstration of the plasma exhaust reprocessing.

This paper discusses the possibility that tritium might exchange with water trapped in aluminum anodize cryopanels in JET which prompted a test program at the Tritium systems Test Assembly, TSTA. Los Alamos, New Mexico. JET furnished two test pieces of cryopanel which were exposed to tritium at approximately liquid nitrogen temperature and 25 torr pressure for nearly two weeks. One specimen was removed and the retained tritium was measured. The second specimen was subjected to several increasing temperature vacuum bakeouts and the effectiveness of the bakeouts were inferred from the pressure history of the chamber. When the retained tritium in the second specimen was measured, it was found that nearly 96% of the tritium, as measured in the first specimen, had been removed during the vacuum bakeouts. If the tritium retained in the cryopanel without bakeout were scaled to JET conditions according to a linear pressure-time relationship, the tritium expected to become trapped in the JET cryopanels would be approximately 0.6 gram.

In 1988, a prototypical vacuum system was added to the Tritium Systems Test Assembly (TSTA) at Los Alamos National Laboratory. Since then various pumping scenarios, which might be expected in a fus...

At the Tritium Process Laboratory (TPL) in the Japan Atomic Energy Research Institute, the Thermal Diffusion process is applied to enrich and recovery tritium diluted by the operation and experiments of the other apparatus installed in the gloveboxes. The apparatus is required to process 200-liter of hydrogen isotope mixture containing up to lg tritium by batch operation and enrich tritium to 90%. Preliminary studies were performed numerically as well as experimentally, and good agreement was obtained. Based on the results, the apparatus was designed. Major components are four 2.5m-high diffusion columns, reservoirs, pumps, active metal beds and a mass spectrometer.

This report contains: crystallographic analysis; phase diagrams in Pd-alloy/H/sub 2/, D/sub 2/ systems; diffusivity of /sup 3/He in Pd-alloy membrane; problems for tritium compatible design of Pd-diffuser; and review of the past work done by authors.

The first loop operation tests of the Tritium Systems Test Assembly (TSTA) with 100 grams-level of tritium were performed at the Los Alamos National Laboratory (LANL) in June and July, 1987. The July run was resumption of the June run, which was halted because of a loss of cryogenic refrigerant in the hydrogen isotope separation system.

Cryogenic distillation experiments were performed at TSTA with H-D-T system by using a single column and a two-column cascade. In the single column experiment, fundamental engineering data such as the liquid holdup and the HETP were measured under a variety of operational conditions. The liquid holdup in the packed section was about 10--15% of its superficial volume. The HETP values were from 4 to 6 cm, and increased slightly with the vapor velocity. The reflux ratio had no effect on the HETP under the condition that the vapor velocity was almost constant. For the two-column experiment, dynamic behavior of the cascade was observed.

In March of 1988 full operation of the 4-column isotope separation system (ISS) was realized in runs that approximated the design load of tritium. Previous operations had been fraught with operating difficulties principally due to external systems. This report will examine the recent highly successful 6-day period of operation. During this time the system was cooled from room temperature, loaded with hydrogen isotopes including 109 grams of tritium, integrated with the transfer pumping, impurity injection, and impurity removal systems, as well as the remote computer control system. At the end of the operation 12 grams of tritium having a measured purity of 99.987% (remainder deuterium) were offloaded from the system. Observed profiles in the columns in general agree with computer models. A Height Equivalent to a Theoretical Plate (HETP) of 5.0 cm is confirmed.

A Monte Carlo computer code for analyzing free molecular gas flow has been developed to study the pumping characteristics of compound cryopumps for plasma chamber evacuation of fusion reactors. The code can deal with complex internal geometries of the pumps which commonly consist of cryopumping surfaces surrounded with elements like baffles, shields, and reservoirs. This code was used to study the pumping performance of a compound cryopump in the Tritium Systems Test Assembly (TSTA) at Los Alamos National Laboratory. The results show that the calculated pumping speeds are strongly effected by the geometrical models employed in the calculations, and that an analysis based on a detailed model is essential to estimate the performance of compound cryopumps.

An experimental apparatus has been developed to carry out tritium permeation experiments for candidate first-wall materials subjected to a high flux of low energy tritium ions, and installed in a g...

At the Tritium Process Laboratory (TPL) in the Japan Atomic Energy Research Institute, an apparatus for the Fuel Cleanup Process was designed, fabricated and installed for the experiments with up to 1g of tritium. The function of the system is continuous processing of a simulated plasma exhaust and separation of hydrogen isotopes and impurity elements in it. Main components are, palladium diffusers, catalytic reactors, cold traps, an electrolysis cell and zirconium-cobalt beds. The apparatus was installed in a glovebox and tested with hydrogen by early 1988.

An intermetallic compound of zirconium-cobalt was prepared, and the pressure-composition isotherms for the ZrCo-H system were measured in the pressure range from 10 Pa (0.1 Torr) to approx. =130 kPa (1000 Torr) and in the temperature range from 130 to 400/sup 0/C. The equilibrium hydrogen pressures of plateaus under the the experimental conditions were one or two orders of magnitude higher than that of a uranium-hydrogen system. A pronounced hysteresis between hydrogenating isotherms and dehydrogenating ones was observed. Based on the results, ZrCo is proposed as a substitute for uranium for the purpose of recovering, storing, and supplying gaseous tritium.

An experimental apparatus for the development of cryogenic hydrogen isotope separation system (ISS) was designed and fabricated at the Tritium Process Laboratory (TPL) in Japan Atomic Energy Research Institute (JAERI). This apparatus will serve to study the separation characteristics of hydrogen isotope mixture with 10/sup 4/ Ci of tritium. It consists of two distillation columns with isotopic equilibrators for H-D-T mixtures and can be operated with both single column distillation mode and two interlinked cascade modes. Installation of this system in a glovebox was completed by late January, 1988. Tests with tritium will start late 1988.

A breeder blanket interface for an aqueous lithium salt blanket is defined for TSTA. High calculated radiolysis rates result in a high overpressure in the blanket and the need for a depressurizer a...

Nuclear Fusion Council, Atomic Energy Commission of Japan, has started to review the nuclear fusion R and D plan for the next stage, post JT-60. The council launched a subcommittee on fundamental issues in the nuclear fusion development in 1985, for review of the basic strategy of a development plan. The subcommittee presented an interim report in Feb. 1986 after 6 months discussion and the report was approved by the Nuclear Fusion Council. Two major R and D programs described in the interim report are the development of a Tokamak type large facility and the comprehensive development of the fusion reactor technology. The latter means to promote the reactor technologies which will be essential in the future to construct not only a D/T burning but also a DEMO reactor. The Nuclear Fusion Development Program in Japan is shown. The interim report recommended to organize two subcommittees to establish an integrated national R and D plan; one was for the design of the next step large facility and the other was for the R and program of the fusion technology. The subcommittee for the latter consisted of 7 working groups; one of them was organized for the tritium technology.

The pressure-composition isotherms for the LaNi3Mn2 -H and D systems were obtained in the temperature range 25–300 C. The absorption plateau pressure increases from 4 Pa at 25 C to 200 kPa at 300 C...