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The Tritium Systems Test Assembly (TSTA) at Los Alamos National Laboratory has conducted its longest continuous integrated loop operation to data. This provided an opportunity to test some hitherto unproven capabilities of the TSTA fuel cleanup system (FCU). The purpose of the FCU is to remove impurities from a stream of hydrogen isotopes (Q/sub 2/) representative of torus exhaust gas. During this run, impurities loadings ranging from 60 to 179 sccm of 90% N/sub 2/ and 10% CH/sub 4/ were fed to the FCU. Each of the two FCU main flow molecular sieve beds (MSBs) were filled to breakthrough three times. The MSBs were regenerated during loop operations. The experiment yielded two principle findings. The first is that using the cryogenic molecular sieve is very robust method for removing impurities from fusion fuels. While loop flow rates, pressures, and impurities concentrations varied, the MSBs continued unaffected, completely removing impurities. The second is that the first step in the MSB regeneration process proved to be very effective. >

Tritium Systems Test Assembly (TSTA) in the Los Alamos National Laboratory is a reactor-scale fusion fuel processing loop and is operated by the Japan Atomic Energy Research Institute (JAERI) and the USDOE under the collaboration. An extended experimental campaign of the TSTA loop was performed with 100 grams of tritium in April-May 1992 in order to simulate a steady-state fusion fuel processing for 25 days. Continuous processing of simulated plasma exhaust (DT and H mixture, He, CH/sub 4/ and N/sub 2/) was successfully demonstrated. Impurity processing was successfully tested by two different techniques. US developed Fuel Cleanup System (FCU) purifies DT by cryogenic molecular sieve beds and decomposes tritiated water by Magnesium beds. Japanese developed J-FCU is based on purification by permeation through palladium alloy membrane and vapor electrolysis with a ceramic electrolyte cell. Isotope Separation System was stably operated with four interlinked columns and continuously produced pure tritium and deuterium stream while exhausting protium impurity. Real-time analysis in the ISS process was demonstrated with the laser Raman Spectroscopy. The result demonstrated the safe and stable operation of reactor-scale fusion fuel loop in a steady state.

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...

A novel method for the highly regioselective deprotonation of the indole alkyl substituents has been established by the particular sequence of base treatments. This success may be due to the aromatic stabilization of cross [6e/4p] conjugated systems. We are presently pursuing further application revolving around this methodology

In 1987 the US Department of Energy (DOE) and th Japan Atomic Energy Research Institute (JAERI) signed collaborative aggrement for the joint operation and join funding of the Tritium Systems Test Assembly (TSTA) for a five year period ending June 1992. The tritium research and development accomplished during this five year period has provided a very valuable data base for the fusion energy program. During the past year a number of significant experiments were completed and major programmatic milestones were met. This paper summarizes some of the major accomplishments during the initial five year collaboration. The integrated TSTA gas processing loop was operated continuously for 25 days. Both the JAERI fuel cleanup system and the original TSTA fuel cleanup system were operated under similar conditions of flow, pressure, and impurity content of the DT gas. The isotope separation system was operated continuously, using the recently installed laser Raman spectroscopy system for in situ analysis of the gas in the loop. Additional studies include studies on the interaction of tritium with sulfur hexaflouride, studies on the compatibility of cryosorption pump materials with tritium, and studies of tritium interaction with gaseous materials such as methane and deuterated methane.

The Tritium Process Laboratory (TPL) has been constructed to carry out research and development on tritium processing and tritium safety handling technologies for fusion reactors. Since 1988, many tritium experiments including simulated plasma exhaust gas cleanup, hydrogen isotope separation, tritium accountability, tritium removal and containment, and so on have been carried out using gram level tritium at TPL. The experiments have produced remarkable accomplishments on tritium technology for fusion reactors.

We analyzed the bond interactions at the transition state of the Cope rearrangement of 1,5-hexadiene to disclose the significant participation of the geminal σ bonds at the reacting centers. The electron-donating σ bonds at the Z-positions and the electron-accepting σ bonds at the E-positions in the 1-substituted 1,5-hexadienes were predicted from the geminal bond participation to enhance the reactivities. For the reverse reactions, the 3-substituted 1,5-hexadienes were similarly predicted to rearrange more readily into the 1-substituted ones with the electron-donating σ bonds at the Z-positions. The predictions were confirmed by the density functional theory calculations.

This paper will review the current state-of-art of organoaluminum- or organoboron-mediated asymmetric reactions in the natural product synthesis. The newly developed methods heavily depend on the characteristic features of main group organometallic compounds. Asymmetric Diels-Alder reaction, pioneered by Walborsky (ref. l), has been established as one of the most important tools in modern synthesis of natural products. In the study of the influence of concave-convex topological features on asymmetric Diels-Alder reactions, a number of fascinating chiral auxiliary groups were reported (ref. 2). However, readily available dimen- thy1 fumarate appears to deserve careful reinvestigations since its primitive topological feature seems to be underestimated. Thus, the Lewis acid coordinated fumarate is considered to exist in the s-trans form predominantly and the two menthyl groups should cooperatively cover the re face of the molecule. A series of dienes was then subjected to Diels-Alder reaction with or- ganoaluminum reagent at low temperature and all the attempted reaction proceeded with excel- lent stereoselection (ref. 3).

An efficient and stereospecific ring formation from unsaturated alcohols, which in turn are prepared by regio- and stereospecific ring opening of acetals, is described

Uranium isotope separation by redox chromatography is analytically studied. The periodic withdrawal of products and tails and the introduction of natural feed are simulated on the assumption of a square cascade for a uranium adsorption band. The influences on the separative power and the lead time until product withdrawal are investigated by varying the magnitude of the isotope separation factor, uranium band length, tails concentration, and so on. Simulating calculations indicate that using ion-exchange resins to achieve uranium isotope separation requires a very long lead time for the production of highly enriched uranium.

The Tritium Process Laboratory (TPL) was constructed at the Japan Atomic Energy Research Institute (JAERI) in June, 1985. The objectives of this laboratory are the research and development of the fusion reactor fuel processing system and safe handling technology of large amounts of tritium. Total tritium inventory in the facility is 10 g and each experiment will be conducted with up to 1 g. Safety systems have been in operation since 1985 and have been tested without tritium. Tritium removal systems, gloveboxes, vacuum pumping system and tritium storage systems etc. have been proven to work as designed so that tritium can be handled safely in this facility. The various items of experimental apparatus were designed, fabricated, installed and checked early in 1988. First tritium was shipped from Oak Ridge National Laboratory in February, and then the “hot” operation was initiated in March, 1988.

A mathematical simulation procedure is developed for a single cryogenic distillation column with a feedback stream and a catalytic equilibrator used for protium-tritium (HT) separation. Large error...

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.

The decomposition of tritiated water vapor by means of solid oxide electrolysis cells has been proposed for the application to the D-T fusion reactor system. This method is essentially free from problems such as large tritium inventory, radiation damage, and generation of solid waste, so it is expected to be a promising one. Electrolysis of water vapor in an argon carrier was performed using a tube-type stabilized zirconia cell with porous platinum electrodes over the temperature range 500–950°C. High conversion ratios from water to hydrogen, of up to 99.9%, were achieved. The characteristics of the cell were deduced from the Nernst equation and the conversion ratios expressed as a function of the IR-free voltage. Experimental results agreed with the equation. The isotope effect in electrolysis is also discussed and experiments with heavy water were carried out. The obtained separation factor was slightly higher than the theoretical value.

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.

A ZrCo intermetallic compound is proposed as the material for recovery, storage and supply of gaseous tritium. It is a substitute for the uranium that has been extensively used for this purpose in spite of its restricted handling as a nuclear fuel material. Pressure-composition isotherms of a ZrCoH2 system were investigated and this material proved to be applicable and advantageous. Some ZrCo beds were designed, fabricated and tested for actual use. A bed for the handling of large amounts of hydrogen isotopes was developed. The test establishes ZrCo beds as practical components for tritium service.

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.

The use of chiral organoaluminum reagent as a catalyst to resolve simple ketoepoxides is explored. The optically pure ketoepoxide 10 was recovered after 80% conversion. The recovered pure epoxide is a useful chiral building block in the synthesis of chiral terpenes. The method applies for the short asymmetric synthesis of the juvenile hormone by the synthetic route which depends on the palladium-catalyzed coupling process.

A design for a palladium diffuser and fuel cleanup system for a deuterium-tritium fusion reactor is proposed. The feasibility of the palladium-alloy membrane method is discussed based on early stud...

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.

Employing the homochiral acetal template, asymmetrization of meso-substituted cyclohexanones is explored. By the use of optically-active 2,4-pentanediol as a chiral protecting group, highly diastereoselective acetal cleavage is achieved when treated with organoaluminum reagent. Dialkylaluminum amides are also effective reagents for this reaction.

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.

This paper will review the current state-of-art of organoaluminum- or organoboron-mediated asymmetric reactions in the natural product synthesis. The newly developed methods heavily depend on the characteristic features of main group organometallic compounds. Asymmetric Diels-Alder reaction, pioneered by Walborsky (ref. l), has been established as one of the most important tools in modern synthesis of natural products. In the study of the influence of concave-convex topological features on asymmetric Diels-Alder reactions, a number of fascinating chiral auxiliary groups were reported (ref. 2). However, readily available dimen- thy1 fumarate appears to deserve careful reinvestigations since its primitive topological feature seems to be underestimated. Thus, the Lewis acid coordinated fumarate is considered to exist in the s-trans form predominantly and the two menthyl groups should cooperatively cover the re face of the molecule. A series of dienes was then subjected to Diels-Alder reaction with or- ganoaluminum reagent at low temperature and all the attempted reaction proceeded with excel- lent stereoselection (ref. 3).

A short synthetic route to C 16 -juvenile hormone is described which depends on new oxirane ring opening methodology and which also involves the joining of intermediate 8 and 12 in a one flask operation to construct the sesquiterpene structure.

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.

Reports on remarkable improvements in the previously reported mathematical model for multicomponent separating cascades, which are applicable to the cases where the interstage flows and the stage separation factors are input variables for the calculations. The number of the independent variables is greatly decreased for much more efficient iterative calculations by the multidimensional Newton-Raphson method. Particularly, if the stage separation factors are independent of concentrations of the up and down streams, the improved model presents great decreases both in the computation time needed at each iterative step and in the number of total iterations. Several numerical experiments made for a five-component system of N/sub 2/-O/sub 2/-/sup 41/Ar-/sup 85/Kr-/sup 133/Xe, which are separated by using the porous membrane method, indicate that the total computation time is shortened by almost two orders of magnitude if the improved model is used.

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.

Selective absorption of laser photons was studied for the separation of a gaseous mixture by laser-induced thermal diffusion. It was found that the separation factor depends on the gas pressure in a way similar to that for normal thermal diffusion processes.