WO1993001601A1 - Methode de reproduction constante d'une charge elevee de deuterium et d'obtention de tritium dans des electrodes de palladium - Google Patents

Methode de reproduction constante d'une charge elevee de deuterium et d'obtention de tritium dans des electrodes de palladium Download PDF

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WO1993001601A1
WO1993001601A1 PCT/US1992/005717 US9205717W WO9301601A1 WO 1993001601 A1 WO1993001601 A1 WO 1993001601A1 US 9205717 W US9205717 W US 9205717W WO 9301601 A1 WO9301601 A1 WO 9301601A1
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electrode
discharging
cell
charging
palladium
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PCT/US1992/005717
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Krystyna Cedzynska
Denton C. Linton
Fritz G. Will
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University Of Utah Research Foundation
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    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21B—FUSION REACTORS
    • G21B3/00—Low temperature nuclear fusion reactors, e.g. alleged cold fusion reactors
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E30/00—Energy generation of nuclear origin
    • Y02E30/10—Nuclear fusion reactors

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  • the present invention relates generally to the diffusion of isotopic hydrogen into hydrogen-absorbing electrodes, and more particularly to a method for consistently achieving a high loading ratio of isotopic hydrogen in hydrogen absorbing electrodes. Specifically, the present invention relates to a method that has consistently achieved a sufficiently high deuterium loading ratio in palladium electrodes that the generation of tritium has been consistently observed.
  • palladium may absorb large quantities of hydrogen and its isotopes. Upon absorption, two phases are formed, known as the a-phase and the b-phase, in which the palladium hydride PdH n or deuteride PdD n are formed. Moreover, the study of absorption of isotopic hydrogen in palladium electrodes has been the subject of considerable work over the years. In general, consistent results have not been easily obtained.
  • a palladium foil electrode was treated by washing in hot concentrated nitric acid, then washing it in twice-distilled water, and then heating it to white heat in air. After this the electrode was immersed in a normal solution of sulfuric acid, anodically polarized at 0.0002 A until its potential with the current flowing assumed a value of about 1 V, and then saturated with hydrogen, the potential and time being measured.
  • This method of preliminary treatment of the electrode, with the complete exclusion of cathodic polarization was said to give an electrode of low activity, the deactivation of the electrode being variable according to the duration and intensity of the heating, and apparently palladium electrodes sufficiently active with respect to the absorption and evolution of hydrogen can be made only by alternate anodic and cathodic polarization.
  • Poisonous species can be present in either insufficiently purified electrolytes or in the hydrogen or other gas streams or be leached from the electrolyte container or specimen holder.
  • copper, zinc or mercury being introduced into the electrolyte from electrical connections. It is further said that despite the elimination of catalytic poisons from the sources listed, extremely misleading data can be obtained if specimens are not efficiently cleaned before, introduction into solution since subsequent activation procedures, such as anodization or cathodization, may not thereafter be entirely successful.
  • An electrode surface that is much less readily poisoned may be obtained by "palladizing", i-,e-, by plating the palladium (or palladium alloy) with a layer of palladium black from a dilute solution of chloropalladous acid (e.g., 2% PdCl 2 in 0.1N HCl).
  • a dilute solution of chloropalladous acid e.g., 2% PdCl 2 in 0.1N HCl.
  • the reaction generates low levels of neutrons, much higher levels of tritium, and heat possibly in excess of that explained by the generation of neutrons or tritium.
  • the reaction mechanism therefore appears to involve the fusion of deuterium to form neutrons and tritium, but the observed reaction rates are too high to be explained by any known kind of fusion reaction between deuterium at low temperature. More puzzling is the fact that the rate of tritium generation appears to be enhanced, relative to rate of neutron generation, by a factor on the order of about ten million.
  • the dilatometry method also has problems. Due to the fact that the deuterium will enter the palladium so readily it has been shown that the palladium can fill to the point that it will crack and bulge the metal. This gives an overestimate of the amount of deuterium in the palladium. A few groups have applied resistance measurement techniques [See J. P. Burger, D. S. MacLachlan, R. Mailfert, B. Sonffache, Solid State Comm. 17, 277 (1975)]. Some of them have found that the curves are parabolic in shape which indicates a maximum resistivity. It appears that beyond this point the palladium deuterium cathode behaves as a semiconductor. Under these conditions, the resistivity measurements are not adequate for precise loading information.
  • a simple direct way to measure loading is by a volumetric measurement of the oxygen and deuterium produced during electrolysis. [See J. Divisek, L. Furst, J. Balej, J. Electroanal. Chem. 278, 99 (1990).] This technique has been used to measure loading as a function of time. The loading has been found to be generally in the range of 0.65 to 0.85 for the saturation or equilibrium atomic loading ratio, D/Pd. In most cases, prolonged electrolysis does not cause further increases in loading ratio and only in a few cases, loading ratios of approximately 1.0 may have been achieved but the reasons for this are obscure.
  • Scott et al. "Measurement of Excess Heat and Apparent Coincident Increases in the Neutron and Gamma-Ray Count Rates During The Electrolysis of Heavy Water," Fusion Technology, Vol. 18, Aug. 1990, pp. 103-114, for example, discloses on page 114 that a decrease in electrolyte temperature appeared to be most efficient for initiating excess power generation, and in two cases, increases in neutron count rate appeared to be related to system perturbations such as cathode current cycling or electrolyte temperature change. A closed-system test shown in FIG. 7 of Scott et al.
  • Pulsed cathode current was reported for a cell described on page 67 of P.K. lyengar and M. Srinivasan, "Overview of BARC Studies in Cold Fusion," Conference Proceedings of the First Annual Conference on Cold Fusion. Salt Lake City, Utah, March 28-31, 1991, pp. 62-81.) At first a current of 1 ampere was used for the electrolysis. After about 30 hours of operation, current pulsing between 1 and 2 ampere at one second intervals was adopted. After a charge of 17.5 ampere-hours had been passed, the first neutron emission was detected. As shown in Fig.
  • isotopic hydrogen such as deuterium is electrolytically loaded into a hydrogen absorbing electrode by alternately charging and discharging the electrode in a plurality of cycles, each cycle including charging of the electrode with isotopic hydrogen approximately to a saturation level and then discharging of the electrode to a predetermined retention level.
  • the electrode is charged approximately to a saturation level by charging for a predetermined duration of time, and the electrode is discharged to a predetermined retention level by discharging until a predetermined cell voltage threshold is reached at a predetermined discharge current.
  • the predetermined cell voltage threshold is a positive voltage on the electrode such as 0.8 volts that is just below the voltage (about 1.2 volts) at which oxygen evolution at the electrode could thermodynamically occur.
  • the electrolytic cell includes a microporous separator preventing recombination on the palladium cathode of isotopic hydrogen being discharged from the electrode with oxygen having been generated during the charging of the electrode.
  • charging for each cycle is performed up to a maximum rate that is decreased for subsequent cycles following an initial cycle.
  • the electrode is discharged abruptly during each cycle, for example by ramping-down or stepping-down a cell current set-point while limiting the magnitude of the discharge voltage to the predetermined cell voltage threshold at which discharging is terminated.
  • palladium or palladium alloy electrodes are pre-treated by palladizing to deposit a thin surface layer of palladium black, and then the electrodes are preloaded with isotopic hydrogen gas in a gas-filled vessel.
  • a 2 mm diameter Pd wire purchased from Hoover & Strong, Inc. (99.99% purity) is palladized by electrodeposition of a thin coating of Pd black, then pre-loaded in deuterium gas at approximately atmospheric pressure for about 12 hours, then immediately transferred to an electrochemical cell having a 0.5 M D 2 SO 4 in D 2 O electrolyte, initially charged electrolytically at current density of 10-50 milliamps/cm 2 for 1,000 to 2,000 minutes, then discharged at current densities sequentially of 30, 10, and 5 milliamps/cm 2 while limiting the cell voltage to below 1 volt to avoid oxygen evolution on the palladium electrode, immediately followed by reloading the electrode with deuterium, employing a current density of 10 or 20 milliamps/cm 2 for at least 1,000 minutes, and repeating discharging and charging under these conditions for a total of 4-5 times.
  • This procedure leads to a stepwise increase in the D/Pd loading ratio, ultimately obtaining loading ratios in the vicinity of 1.
  • This procedure has been successful in 4 out of 4 experiments for consistent reproduction of the high loading ratio and consistent reproduction of tritium generation. No tritium generation was observed in four H 2 SO 4 control cells operated simultaneously. Evidence for neutron generation was also observed from all four D 2 SO 4 cells. A single anomalous temperature excursion was observed in one of the four cells.
  • FIG. 1 is a schematic diagram in cross-section of a test cell used for loading ratio and tritium generation experiments
  • FIGS. 2A and 2B are graphs of the deuterium to palladium loading ratio, and the hydrogen to palladium ratio, respectively, as a function of time obtained in a pair of cells wired in series to have a similar cycling of cell current in accordance with the present invention during one experiment;
  • FIGS. 3A and 3B show results of an experiment similar to that reported in FIGS. 2A and 2B, but with a decrease in current density during a latter portion of a first cycling of the cell current;
  • FIGS. 4A and 4B show results of a loading experiment using a palladizing pre-treatment of the palladium electrode to obtain a small increase in the loading ratios
  • FIGS. 5A and 5B show results of a loading experiment using gas-phase pre-loading of palladized palladium electrodes with deuterium or hydrogen, respectively, to obtain an additional small increase in the loading ratios;
  • FIGS. 6A and 6B show results of a loading experiment using gas-phase pre-loading of palladium electrodes, but without using a palladizing pre-treatment, and using a single cycling of the loading current followed by pulsing of the loading current;
  • FIGS. 7A and 7B show graphs of the deuterium to palladium loading ratio, and the temperature of the palladium and platinum electrodes, in a deuterium cell during a loading experiment with a palladized palladium electrode;
  • FIGS. 8A and 8B show the results in a hydrogen cell during the experiment also reported in FIGS. 7A and 7B;
  • FIGS. 9A to 9E show graphs of data from a set of tritium generation experiments; in particular, FIG. 9A shows a graph of the deuterium to palladium loading ratio as a function of time for a second one of the tritium generation experiments, FIG. 9B shows a graph of the electrode temperatures as a function of time in a deuterium cell for the second one of the tritium generation experiments, FIG. 9C shows a graph of the hydrogen to palladium loading ratio as a function of time for the second one of the tritium generation experiments, FIG. 9D shows a graph of the deuterium to palladium loading ratio as a function of time for a third one of the tritium generation experiments, and FIG. 9E shows a graph of the hydrogen to palladium loading ratio as a function of time for the third one of the tritium generation experiments;
  • FIG. 10 shows the tritium distribution observed in four palladium cathodes from deuterium cells after four respective tritium generation experiments
  • FIGS. 11A and 11B show neutron count data for the deuterium cells in the first and third tritium generation experiments, respectively.
  • FIGS. 12A and 12B show the electrical power input, and the temperatures observed for the palladium and platinum electrodes, respectively, during a latter portion of the second tritium generation experiment;
  • FIGS. 13A and 13B show expected cell potential and programmed cell current in a system wherein a cell is controlled in accordance with the invention by operating a digital computer;
  • FIG. 14 is a block diagram of a system including a battery of cells and a digital computer for cycling the current in each of the cells in accordance with the invention
  • FIG. 15 is a schematic diagram of a thermistor bridge and amplifier circuit used in the block diagram of FIG. 14;
  • FIG. 16 is a schematic diagram of a cell power supply used in the block diagram of FIG. 14;
  • FIG. 17 is a flowchart of a program executed by the computer in the system of FIG. 14 for cycling the current in each of the cells in accordance with the invention
  • FIG. 18 is a flowchart of a sample timer interrupt routine that the digital computer of FIG. 14 executes at periodic sample times to collect cell data and to change the cell currents;
  • FIG. 19 is a flowchart of a routine executed once for each cell at each sample time, in order to determine whether the current for each cell should be changed at each sample time, and if so, to change the cell current and to compute the next time that the current for the cell should be changed;
  • FIG. 20 is a flowchart of a routine executed to repeat cycling of cell current in accordance with the invention, beginning with a first discharge cycle, in an attempt to restore a high loading ratio in the cell.
  • a volumetric technique was used for continuous measurement of respective deuterium and hydrogen uptake during loading of palladium cathodes while imposing non-steady state diffusion conditions upon the cathodes.
  • Two parallel experiments were conducted, one with deuterium and the other with hydrogen, in order to compare the loading ratios obtained under otherwise identical conditions.
  • the hydrogen or deuterium uptake was determined by a volumetric measurement of the difference between the D 2 or H 2 and the O 2 liberated under electrolysis.
  • the experimental electrochemical cell 20, which was fabricated from laboratory grade glassware, is shown in FIG. 1.
  • the cell 20 eliminated contact between hydrogen or deuterium and oxygen gas by using a fritted glass cell divider 21 between the cathode 22 and the anode 23 of the cell.
  • the fritted glass cell divider 21 was in the form of a fritted glass cylindrical tube 2.5 cm diameter ⁇ 3.0 cm long in coaxial relationship with the cathode 22 and the anode 23 and separating a cathodic compartment 24 from an anodic compartment 25.
  • the fritted glass tube 21 had holes of 200 microns porosity through which electric current was passed while preventing recombination of the deuterium or hydrogen and oxygen discharged from the electrodes.
  • the cathode 22 was a 1.0 mm diameter by 3.0 cm long cylindrical wire placed at the center of the cell 20.
  • the anode 23 was a cylindrical piece of 0.1 mm thick Pt foil surrounding the fritted glass tube to provide uniform current distribution during electrolysis.
  • the cathodic compartment 24 and anodic compartment 25 were separated on the bottom part of the cell 20 with a "TEFLON"
  • two calibrated thermistors 31, 32 were used. One of these 31 was employed to measure the cathode temperature. It was enclosed in a glass capillary tube 33 and bonded to the cathode with thermally conductive epoxy. For still better heat conduction, the thermistor 31 was embedded in thermal joint compound inside of the glass capillary tube 33. The second thermistor 32 was employed to measure the temperature in the anode compartment 25. It was positioned as close as possible to the Pt foil of the anode 23.
  • Both the cathodic and anodic compartments 24, 25 had two fittings 35, 36 and 37, 38 each for gas inlet and outlet.
  • the cathodic and anodic compartments 24, 25 were connected by an exterior loop 39 through valves 40, 41 so that the gases could recombine on a platinum catalyst 42 placed above the anode electrolyte.
  • the electrolyte volume in the cell was approximately 38 cm 3
  • the total gas volume was approximately 300 cm 3 .
  • a water-filled manometer 43 comprised of two burets 44, 45 which were connected at their lower ends with flexible tubing 46, was connected to the port 38 of the cell 20 through a valve 47.
  • the manometer 43 was used to measure changes in the gas volume above the electrolyte 28.
  • a first buret 44 was initially filled with water 48. By adjusting the relative height of the second buret 45, the pressure in the cell 20 was maintained at atmospheric pressure. All joints were of ground glass, greased with silicone to ensure a vacuum-tight system.
  • the system was kept at constant pressure, so that the resulting decrease in the gas volume of the cell 20 was a direct measure of the quantity of deuterium or hydrogen absorbed by the palladium cathode 22. Corrections were made for atmospheric pressure and temperature. The system was regularly tested for leaks by moving the second adjustable buret 45 and pressurizing the cell.
  • H cell 0.5 M D 2 SO 4 /D 2 O electrolyte for the deuterium cell
  • D cell 0.5 M D 2 SO 4 /D 2 O electrolyte for the deuterium cell
  • the D 2 SO 4 solution was made by diluting concentrated D 2 S0 4 (98%; Aldrich Chem. Co. Inc.) in D 2 O, and the H 2 SO 4 solution was made by diluting concentrated H 2 SO 4 (96%; Baker Analyzed Reagent) in H 2 O.
  • Deuterium gas 99.99% purity UN1954 from Cryogenic Rare Gas Comp.
  • hydrogen gas 96% from US Welding Comp.
  • Palladium was obtained from Aesar (Johnson Matthey; 1 mm diameter wire; 99.995% purity). The palladium as received from the manufacturer was wiped clean with a clean paper tissue wetted with deionized water.
  • the surface of a palladium cathode 22 was activated by electrodepositing palladium black onto the surface of a palladium rod.
  • the palladizing solution was 0.05 M PdCl 2 in 0.1 M DCl and for Pd-cathode used in "H” cell palladizing solution was 0.05 M PdCl 2 in 0.1 M HCl.
  • Palladizing conditions were 20 mA/cm 2 current density for 60 seconds in both experiments.
  • the palladium cathodes were preloaded with D 2 or H 2 in a gas-phase system.
  • Platinum foil (0.1 mm thick: 99.98%) obtained from Johnson Matthey Electron., was used to fabricate the cylindrical anode 23.
  • the anode was provided with a platinum black layer, by electrodepositing platinum black from a PtCl 2 solution.
  • a piece of Fuel Cell Grade Pt Catalyst on Ag plated Ni screen (ESN) electrode (E-TEK Inc.) was used.
  • the electrolytic cell was initially evacuated and then refilled with D 2 or H 2 gas of ambient pressure.
  • the palladium electrode 22 was made cathodic and a constant charging current of 50, 20 or 10 mA/cm 2 was passed through the cell.
  • This oxygen was catalytically recombined with deuterium (or hydrogen) gas in the oxygen compartment of the cell at the catalyst 42 to form liquid water. Since the system was kept at constant atmospheric pressure by adjusting the water level in the burets 44, 45, the resulting decrease in the gas volume of the cell 20 was a direct measure of the quantity of deuterium (or hydrogen) absorbed by the palladium.
  • the palladium electrode 22 was made anodic and sequential constant discharging currents of 30, 10 and 5 mA/cm 2 through the cell. The voltage of the cell was monitored and the discharge current was decreased to the next lower value when the cell voltage reached 0.8 V. Under these conditions, the main reaction occurring on the palladium electrode 22 was the oxidation of deuterium atoms, diffusing out of the palladium, to D+ ions (see equation (1) below). Depending on the surface activity of the palladium electrode, recombination of D atoms to form D 2 gas may also take place to a minor extent (see equation (2) below). Due to the fact that the cell potential is kept below 0.8 V, oxygen evolution did not take place.
  • Deuterium gas was generated on the platinum electrode 23, and therefore the resulting increase in the gas volume of the cell was a direct measure of the quantity of deuterium (or hydrogen) diffusing from the palladium electrode.
  • the reactions on the palladium electrode during discharging (anodic unloading) were:
  • FIG. 2A Data from a typical loading experiment are shown in FIG. 2A for the "D" cell and in FIG. 2B for the "H” cell.
  • the loading level achieved was similar to typical results obtained in LiOD or LiOH electrolyte (0.58 for D:Pd ratio and 0.64 for H:Pd ratio). These ratios, however, were increased by cycling of the electrolytic current, and reached values of about 1.0 for both cathodes (deuterium and hydrogen) after a total of 150 hours of operation.
  • FIGS. 4A and 4B show a similar experiment using palladized cathodes. This experiment shows that a small increase in the loading ratio was observed when palladizing surface pre-treatment of palladium was used. The loading rate was considerably faster than in the experiment using a non-palladized palladium cathode.
  • FIGS. 5A and 5B show another experiment in which the palladium cathodes were palladized and pre-loaded with deuterium or hydrogen in the gas phase.
  • the degree of preloading was calculated from pressure drop measurements and verified by mass differences.
  • FIGS. 6A and 6B show a loading experiment for preloaded cathodes without palladizing.
  • FIGS. 6A and 6B also show long term electrolysis of Pd cathodes (pre-loaded with D 2 or H 2 ) after a first cycling experiment.
  • a loading ratio plateau 61 of about 0.79 for D/Pd and a loading ratio plateau 62 of about 0.94 for H/Pd was overcome by a discharge cycle at about 1500 minutes.
  • the palladium electrodes were then loaded at 10 mA/cm 2 current density for ⁇ 100 hrs and then for ⁇ 30 hrs palladium cathodes were loaded using variable current density in which the current density was alternately switched at 30 minute intervals between 10 and 20 mA/cm 2 .
  • FIGS. 7A and 7B Two typical electrolysis experiments with 1-mm diameter palladium wires (palladized before being used) are shown in FIGS. 7A and 7B for the "D" cell, and 8A and 8B for the corresponding "H” cell.
  • the D/Pd and H/Pd loading ratios are shown in FIGS. 7A and 8A, respectively.
  • the temperatures of the electrodes were measured with a sensitivity of 0.05°C and response time of a few seconds.
  • the volumetric method was adopted for continuous measurement of the absorption of deuterium (or hydrogen) by palladium during the electrolysis of heavy-water (or light-water) in acidic electrolytes.
  • the electrolytic cell was designed to eliminate contact between oxygen and palladium and, hence, spontaneous recombination between D 2 (or H 2 ) and O 2 at the palladium electrode.
  • the discharging cycles were run at controlled current with a maximum cell voltage below 0.80 volts.
  • the accuracy of the volumetric techniques for loading measurements was confirmed by mass measurements on a 1 mm palladium wire. The accuracy was about 5%.
  • Loading ratios of approximately 1.0 have been achieved when suitable cycling conditions were used for loading and unloading.
  • the first loading cycle was carried out at 10 to 50 mA/cm 2 current density for 20 to 50 hrs respectively, but each subsequent loading cycle was carried out at lower current density ( ⁇ 10 mA/cm 2 ). It appears that carrying out each subsequent loading cycle at lower current density should be done to achieve a maximum loading ratio of 1.0.
  • Each cycle increased the loading ratio by a factor of about 0.05 to 0.1, and a loading ratio of about 1.0 was achieved after the 5th cycle.
  • the normal charging time between discharge cycles should be at least 15 hrs. However, prolonged electrolysis at constant current does not cause further significant increases in loading ratio.
  • the surface pre-treatment by palladizing the surface of the cathodes does not appear to increase the final loading ratios significantly but increases the rate of loading and unloading.
  • Using cathodes pre-loaded in the gas phase also does not appear to increase the final loading level.
  • the gas pre-loading of cathodes decreases the number of cycles needed to achieve the high loading ratios.
  • palladizing prior to gas preloading decrease the time required for gas pre-loading from about 12 hours to about 3 hours.
  • tritium generation was consistently reproduced in four out of four electrolytic cells having palladium cathodes of 2 mm diameter. Deuterium loading ratios near or slightly higher than unity were obtained in these palladium cathodes by the current cycling procedure previously used in the loading experiments described above.
  • the hermetically sealed cell design of FIG. 1 was used. The tritium content of the electrolyte, the Pd and the gas above the electrolyte is determined prior to and after an experiment. Therefore, any increase in tritium content could have only originated from nuclear reactions occurring during the experiment.
  • a light water control cell was always run in electrical series to every D 2 O cell under essentially identical conditions. This procedure always permitted direct comparison of any tritium, neutron or excess heat generation in the D 2 O cell and the H 2 O control cell.
  • Li 2 SO 4 solid 99.99% from Aldrich Chem. Corp. Inc.
  • Deuterium gas was purchased from Air Products & Chemicals Inc. and Alphagaz -Liquid Air Corp. Both suppliers use heavy water electrolysis to produce D 2 gas, and both purchase the heavy water from the same source, Ontario Hydro (Canada). It can be assumed that any tritium contamination in the D 2 gas originates from this heavy water and therefore should be similar for both gas suppliers.
  • the level of tritium contamination in the D 2 gas is given as less than 5 nCi/liter gas, which is the detection limit of the suppliers' chemical analysis. Otherwise, the materials and reagents for the tritium generation experiments were the same as described above for the loading experiments.
  • the recombined heavy water was rinsed out with distilled water and analyzed for tritium in a Beckman LS5000 TD Liquid Scintillation Counter.
  • the tritium content was found to be 0.13 to 0.14 nCi/liter of D 2 . This value was in good agreement with values obtained by Dr. Claytor at Los Alamos National Laboratory on a D 2 tank provided to him.
  • Neutron detection was performed with 3 He tubes. Two tubes each were used to monitor the light and heavy water cells, respectively. They were installed and positioned at a distance of 7 cm from the electrolysis cells in the water baths. To prevent cross talk between the 3 He tubes for the light and heavy water cells, they were spaced 1 m apart and separated by a layer of borate-impregnated paraffin bricks. Neutron data were recorded with an IBM computer system.
  • the amount of D 2 or H 2 , consumed by reaction with the O 2 was precisely equivalent to the number of D or H atoms absorbed by the Pd.
  • the decrease in the gas volumes in the cells was a precise measure for the D/Pd and H/Pd loading ratio, respectively.
  • the gas volume stopped changing when full loading was attained.
  • FIGS. 9A to 9E Typical results of our loading ratio measurements as a function of time are presented in FIGS. 9A to 9E.
  • the second electrolytic deuterium loading experiment (Experiment #2 in TABLE I below), for example, was performed for 12 days.
  • the electrodes were initially charged electrolytically at current densities up to 20 or 50 milliamps/cm 2 for 1,000 to 2,000 minutes, then discharged at current densities sequentially of 30, 10, and 5 milliamps/cm 2 while limiting the cell voltage to below 1 volt to avoid oxygen evolution on the electrodes, immediately reloaded with hydrogen or deuterium at a current density of 10 or 20 milliamps/cm 2 for at least 1,000 minutes, and repeatedly discharged and charged under these conditions for a total of 4 to 5 times.
  • the loading ratio already had a finite value, which for the deuterium cell was 0.68 (FIG. 9A) and for the hydrogen cell 0.75 (FIG. 9C).
  • the loading curves in FIGS. 9A and 9C for this second experiment show a rise in the loading ratio to values of about 0.95.
  • the loading ratio in the deuterium cell appears to continue increasing (FIG. 9A) whereas the loading ratio in the hydrogen cell appears to be saturating (FIG. 9C). Actually, the tendency to saturate is observed in most cases.
  • Table 1 summarizes the tritium analysis results for all four experiments. We have found in other experiments that tritium is generated predominantly at loading ratios in excess of 0.85. Table 1 lists in the first horizontal column the times at which this loading ratio is attained in the four experiments. Table 1 also gives the maximum loading ratios that were achieved in the four experiments, comprising four D 2 cells and four H 2 cells. The loading ratios lie between 0.95 and 1.15, with an experimental uncertainty of ⁇ 0.05. Tritium was not detected in any of the four H 2 control cells.
  • the fourth cell has an enhancement factor of only 1-7, owing to the fact that in this cell a new batch of heavy water was inadvertently used with a tritium contamination level 30-40 times larger than the normal tritium content of the heavy water we have used. The analysis results of the heavy water were obtained only after the electrochemical experiments had been started.
  • the tritium analysis of the palladium cathodes was carried out by analyzing several small pieces cut from the entire electrode. The four samples for analysis were cut one each from the two ends and two from near the center of the cathode. The only exception was the palladium cathode used in experiment three in which the entire electrode was cut into four pieces.
  • FIG. 10 Shown in FIG. 10 are the tritium distributions in the four Pd cathodes in T atoms/g Pd.
  • ND is an abbreviation for "none detected” and means that any tritium present was below the detection of about 5 ⁇ 10 8 tritium atoms/g.
  • the eight pieces near the center of the four electrodes showed a surprisingly tight band of values, namely from 1.2 ⁇ 10 10 to 8.9 ⁇ 10 10 T atoms/g Pd. It appears that the ends of the Pd wires either did not charge as efficiently as the center regions or that tritium escaped from the ends more readily.
  • the detection limit of our analytical procedure was 5 ⁇ 10 8 T atoms/g Pd. Therefore, the tritium levels that we found in the Pd after electrolysis are up to 178 times larger than the maximum possible contamination level before electrolysis.
  • Tritium generation appears to be related to the D/Pd loading ratio; this would not be the case if tritium generation were a surface phenomenon.
  • Tritium is evidently emerging from the palladium during our analytical procedure which involves dissolution of the palladium of aqua regia; if the tritium were adsorbed on the surface of the palladium, it would be very unlikely that it would survive several minutes of exposure to air during the cutting procedure and the transfer into the analytical system,
  • FIG. 11A shows the quadruple neutron event monitored in experiment #1
  • FIG. 11B shows the quadruple neutron event monitored in experiment #3. It is seen that the first event consists of 4 neutrons counted in 320 ⁇ sec whereas in experiment #3 the 4 neutrons are counted in 120 ⁇ sec. While the number of neutron events involving triplets and quadruplets detected in our experiments is quite small, we regard their consistently more frequent occurrence in the D 2 cells as compared to the H 2 controls as significant. Conducting the neutron detection in an underground laboratory would significantly reduce the background and lead to firmer conclusions. Table 2
  • FIG. 12A shows the electrical input power into the cell
  • FIG. 12B shows the temperatures of the Pd cathode and Pt anode as a function of time for the D 2 cell in experiment #2.
  • the D/Pd loading ratio for this experiment was shown in FIG. 9A.
  • the curves shown in FIGS. 12A and 12B relate to the time interval in FIG. 9A from 15,430 to 16,030 minutes.
  • FIG. 12A shows that the electrical input power to the cell increased steadily with time. From FIG. 12B it can be seen that the temperature of the platinum anode stayed constant at 26.84°C during the entire time period of 600 minutes. However, the temperature of the Pd cathode showed a relatively constant value of 26.7°C only in the first 370 minutes of the time period shown. The relatively sudden temperature excursion of the Pd cathode from 26.7°C to 27.7°C followed by less elevated temperatures in the subsequent 70 minutes represents an increase in temperature which can not be explained on the basis of the smoothly rising electrical input power. On the basis of a temperature-power input calibration performed on the cell, the temperature excursion in FIG.
  • the total tritium enhancement in the D 2 cells amounted to factors as high as 50.
  • the total amount of tritium generated was between 4.3 ⁇ 10 10 and 1.1 ⁇ 10 11 T atoms/cm 2 in typically 7 days. This corresponds to an average tritium generation rate from 5.8 ⁇ 10 4 to 2.0 ⁇ 10 5 T atoms/cm 2 /sec.
  • Neutron generation has also been observed in these experiments. However, the neutron levels were fairly small, amounting on very rare occasions to 4 neutrons counted in a time frame of less than 320 ⁇ sec.
  • suitable metals and metal alloys for use as hydrogen absorbing electrodes are those which are capable of dissolving hydrogen in the metal lattice, such as by (i) electrolytic decomposition of hydrogen into atomic hydrogen, (ii) adsorption of the atomic hydrogen on the lattice surface, (iii) diffusion of the atoms into the lattice.
  • the metal is also preferably capable of maintaining its structural integrity when isotopic hydrogen atoms are compressed into the metal lattice. That is, the metal lattice is capable of swelling without cracking as an increasing concentration of isotopic hydrogen atoms are compressed into the lattice.
  • the group VIII metals and particularly palladium, nickel, cobalt, iron, and alloys thereof, such as palladium/silver and palladium/cerium alloys, are favored, although other metals such as platinum and tantalum may also be suitable.
  • the group VIII metals have cubic face-centered lattice structures. With diffusion of hydrogen or isotopic hydrogen atoms into the metal lattice, the lattice is able to adopt an expanded beta form which accommodates a high concentration of diffused atoms into the lattice, and effectively prevents localized strain and cracking.
  • palladium alloy is superior to pure palladium.
  • Palladium alloy can maintain dimensional stability and structural integrity during the process of electrolytic compression.
  • Specific examples of preferred alloys having these properties are palladium (95%)-cerium (5%), and palladium (90%)- silver (10%).
  • the time required for charging an electrode to a saturation level generally is a function of the square of the radius of the electrode.
  • the cycling times indicated in FIGS. 2A and 2B, for example, were selected for a 0.05 cm radius palladium electrode, and similar results for a
  • 0.1 cm radius palladium electrode should require an expansion of the time axis by a factor of 4.
  • it may also be desirable to increase the number of charging and discharging cycles for larger radius electrodes because initially saturation typically occurs at a loading ratio of much less than one, suggesting that the loading ratio at the central region of the electrode may initially be saturated to a much smaller level than the regions of the electrode closer to the surface.
  • the time for charging an electrode to a saturation level is given by the equation:
  • This formula would also give the time for achieving saturation during pre-loading of a palladium electrode with isotopic hydrogen by placing the palladium electrode in an atmosphere of isotopic hydrogen gas.
  • Electrode surface conditions can affect the flux rate of deuterium through the surface into the volume of the electrode. It is known that many metal impurities tend to migrate to the surface of a metal when heated to melt temperature for casting or annealing. For this reason, metals such as palladium which have been formed by casting or annealing may have significant platinum impurities at their surface regions, and may therefore show relatively poor charging efficiency.
  • a solid lattice formed by casting or annealing, followed by machining or the like to remove outer surface regions would have relatively low surface impurities.
  • the machined lattice may be further treated, such as with abrasives, to remove possible surface contaminants from the machining process.
  • Such methods for reducing impurities in a metal lattice are known.
  • the charging rate for an electrode having a clean surface may be improved further by palladizing, and by pre-loading of the electrode with isotopic hydrogen by placing the palladized electrode in an atmosphere of isotopic hydrogen in the gas phase.
  • a hydrogen absorbing electrode When a hydrogen absorbing electrode is used in an aqueous electrolyte, a negative voltage is applied to the electrode to charge the electrode with isotopic hydrogen; in this case the electrode is the cathode of the electrolytic cell.
  • a positive voltage must be applied to the electrode to charge the electrode with isotopic hydrogen; in this case the hydrogen absorbing electrode is the anode of the electrolytic cell.
  • a preferred deuteride molten salt electrolyte is an eutectic LiCl-KCL molten salt saturated with lithium deuteride. Experimental results using such an electrolyte were reported by B.Y. Liaw, P-L Tao, P. Turner, and B.E.
  • the excess heat, as a percentage of the total electrical power input to the cell was said to be about 1512% for a 0.4874 g palladium anode of irregular shape of about 0.99 cm 2 surface area.
  • the palladium anode was charged for more than three weeks at 4 mA/cm 2 and then charged at 290 mA/cm 2 for about 30 hours, 420 mA/cm 2 for 50 hours, and then 692 mA/cm 2 for about 30 hours.
  • the cell voltage at 692 mA/cm 2 was said to 2.453 volts, and the density of the excess heat was said to be in the range of 627 W/cm 3 Pd.
  • the working examples above used an aqueous electrolyte of 0.5 M D 2 SO 4 in D 2 O or H 2 SO 4 in H 2 O, it is not believed that the electrolyte is an important factor for obtaining consistently high loading or tritium generation. Rather, the charging and discharging durations used in the working examples indicate that the cycling procedure of the invention is the most significant aspect of the invention. Therefore the present invention should have application to a wide variety of electrolytes, including non-aqueous electrolytes such as deuteride molten salts.
  • the manner in which the present invention overcomes low loading saturation levels suggests that there is some kind of "memory effect" in the bulk of the palladium, which is probably related to the alpha (a) to beta (b) phase transition in the palladium. For this reason it is likely that the present invention should be useful in achieving high loading levels of isotopic hydrogen in a wide range of hydrogen-absorbing materials that undergo phase transitions during the absorption of hydrogen, for example the group VIII metals and their alloys.
  • the present invention is most easily practiced by operating an electrochemical cell (e.g., the cell 20 in FIG. 1) in such a way that the cell voltage (e.g., of the palladium electrode 22 with respect to the platinum electrode 23) during discharge is constrained within voltage limits, and by alternately charging and discharging the palladium electrode in a galvanostatic (i.e, constant current) fashion.
  • an electrochemical cell e.g., the cell 20 in FIG. 1
  • the cell voltage e.g., of the palladium electrode 22 with respect to the platinum electrode 23
  • galvanostatic i.e, constant current
  • FIGS. 13A and 13B there are shown graphs of the cell voltage and cell current, respectively, for another example of operation of an electrochemical cell in a galvanostatic fashion while constraining the cell voltage within voltage limits.
  • the time scale has been shown to illustrate the charging and discharging times for consistently achieving a high loading ratio of deuterium in a 2 mm diameter palladium wire electrode so that tritium generation is consistently observed.
  • the cell voltage will be defined as the voltage of the palladium electrode in the cell, with the platinum electrode at a ground potential of zero volts, and the cell current will be defined as the current into the palladium electrode.
  • the cell current will be defined as the current into the palladium electrode.
  • FIG. 13A and 13B it is assumed that the electrolyte in the cell provides isotopic hydrogen cations (for example the electrolyte is an aqueous electrolyte) so that the palladium electrode becomes charged with isotopic hydrogen when the cell voltage is negative.
  • the voltage and current axes have been drawn with negative voltages and currents at the tops of the respective graphs and positive voltages and currents at the bottoms of the respective graphs so that charging of the palladium electrode is generally indicated by high curves and discharging of the palladium electrode is generally indicated by low curves. More precisely, charging of the palladium electrode occurs when the curve in FIG. 13B lies above the time axis, and discharging of the palladium electrode occurs when the curve in FIG. 13B lies below the time axis.
  • the charging and discharging for example, is defined by the schedule listed in Table 2 below.
  • the palladium electrode is alternately charged and discharged in a plurality of cycles, each of the cycles including charging the palladium electrode with isotopic hydrogen to approximately a saturation level and then discharging the palladium electrode to a predetermined retention level.
  • the palladium electrode is charged to approximately a saturation level by charging for a predetermined period of time, specified by the schedule of Table 2 below.
  • the palladium electrode is charged gradually by increasing the cell current in a step-wise fashion with steps of -10, -20, -30, -40, and -50 mA/cm 2 .
  • the charging of the palladium electrode is limited so that voltage of the cell is limited to a threshold V NTH to limit evolution of hydrogen gas at the palladium electrode.
  • the desired threshold V NTH is most easily established experimentally by operating the cell potentiostatically while increasing the magnitude of the cell voltage from zero until hydrogen gas is evolved at no more than a tolerable rate.
  • the desired threshold V NTH will depend upon such factors as the conductivity of the electrolyte, the gas pressure in the cell, the hydrogen over-potential of the palladium electrode, and the ability of hydrogen gas bubbles forming at the surface of the palladium electrode to become dislodged from the surface of the electrode and rise to the surface of the electrolyte so as not to substantially interfere with the flow of electrical current in the cell.
  • the charging for each cycle is performed up to a maximum rate that is decreased for
  • the initial cycle has a maximum charging rate of -50 mA/cm 2
  • a second cycle has a maximum charging rate of -20 mA/cm 2
  • a third cycle has a maximum charging rate of -10 mA/cm 2
  • a fourth cycle has a maximum charging rate of -10 mA/cm 2
  • a fifth cycle has a maximum charging rate of -10mA/cm 2
  • a sixth cycle has a maximum charging rate of -10 mA/cm 2 .
  • the palladium electrode is charged up to a high maximum rate, preferably up to a current at which the voltage threshold V NTH is reached, to initiate nuclear reactions.
  • a loaded electrode might be subjected to changing conditions over a period of time so that its loading ratio might decrease.
  • a prolonged temperature excursion for example, might cause deuterium to diffuse out of a palladium electrode, causing nuclear reactions in the electrode to stop.
  • it would be desirable to restore the palladium electrode to a high degree of loading by repeating cycles of the cell current schedule beginning with the discharging of the palladium electrode at a point in the schedule following the initial charging of the palladium electrode.
  • this point is at a time of 4500 minutes, when the cell current is switched abruptly to a discharge current of 30 mA/cm 2 , corresponding to the beginning of the entry in Table 2 having an index value of 6.
  • the discharging is limited so that the voltage of the cell during the discharging is limited to a predetermined cell voltage threshold V PTH .
  • the cell voltage threshold V PTH preferably is selected to be a point just below a voltage at which evolution of oxygen gas at the palladium electrode occurs.
  • the cell voltage threshold V PTH is 0.8 volts.
  • the palladium electrode is discharged to a predetermined retention level by discharging until the cell voltage threshold V PTH is reached at a predetermined discharge current. As shown by FIG. 13A and FIG.
  • each charging phase of a cycle is abruptly terminated and the discharge phase begins abruptly and immediately after the charging phase.
  • the discharging phase during each cycle is performed at a maximum rate of 30 mA/cm 2 immediately after the charging phase of the cycle, and thereafter the rate of discharging is decreased to 10 and then 5 mA/cm 2 during the cycle.
  • the rate of discharging is decreased during each cycle when the cell voltage reaches the cell voltage threshold V PTH .
  • the discharging phase of each cycle is terminated to begin the charging phase of the next cycle when the cell voltage threshold V PTH is reached at the 5 mA/cm 2 discharge current.
  • FIG. 14 there is shown a block diagram of a system including a battery of cells 100 and a digital computer 101 for cycling current to a palladium electrode 102, 103 in each of the cells.
  • the battery of cells 100 for example, has a planar geometry and includes platinum foil electrodes 104, 105, 106 that serve as cell separators and are all connected to ground potential.
  • the platinum electrodes 104, 105, 106 are separated from the palladium electrodes 102, 103 by separator sheets 107, 108 of microporous material such as microporous plastic.
  • each palladium electrode is connected to a respective cell power supply 111, 112.
  • the cell power supplies are controlled by a programmable digital computer 113.
  • a data bus 116 interconnects the computer 113 and the power supplies for the exchange of control data
  • an address bus 115 interconnects the computer and the power supplies 111, 112 to permit the computer to select a particular one of the power supplies for the exchange of data.
  • the cell power supplies 111, 112 are further described below with reference to FIG. 16.
  • the digital computer 113 is programmed, as further described below with reference to FIGS. 17 to 20, to achieve a high degree of loading of deuterium in each of the palladium electrodes 102, 103 by controlling the cell power supplies 111, 112 in accordance with a cell current schedule 117.
  • the cell current schedule for example, is a table of cell current set points and time durations in computer memory in the format of Table 2 above.
  • the computer 113 also has a real-time clock 118 that is used in connection with the cell current schedule 117 to make changes to the settings of the power supplies 111, 112 at the scheduled times.
  • the digital computer has an analog-to-digital converter 119 for periodically sampling the cell voltage and the temperatures of the electrodes in each cell.
  • the digital computer 113 places a predetermined address on the address bus 115.
  • the address is decoded by an address decoder 121, which enables a data register 122 to accept a data code indicating the selected parameter.
  • the code is fed to an analog multiplexer 123, which connects an input of the analog-to-digital converter 119 to a selected palladium electrode 102, 103 to sample the voltage of a cell, or to sample the output of a selected thermistor amplifier 124, 125, 126, 127.
  • the computer 113 After a predetermined conversion time interval required by the analog-to-digital converter 119, the computer 113 reads a digital sample from the analog-to-digital converter by placing an address on the address bus 115.
  • the address is decoded by the address decoder 121, which enables a bus driver 128 to transmit the digital sample over the data bus 116 to the computer 113.
  • FIG. 15 there is shown a schematic diagram of a conventional thermistor amplifier 127.
  • a thermistor 131 associated with the amplifier 127 is a component of a bridge circuit also including resistors 132 and 133 of approximately equal resistance R 1 , and a variable resistor 134.
  • the bridge is energized by a regulated voltage +V R .
  • the output of the bridge is fed to an operational amplifier 135.
  • Resistors 138, 139, 140 and 141 set the gain of the operational amplifier 135. It is known that the performance of the circuit is optimized when the resistance R 1 is equal to the nominal resistance of the thermistor 131, the resistors 138 and 139 have the same resistance R 2 , and the resistors 140 and 141 have the same resistance R 3 .
  • the gain of the amplifier 135 is given by the ratio R 3 /R 2 .
  • the variable resistor 134 is adjusted to null the output of the bridge at a nominal temperature, and a null output of the bridge is indicated by a zero (mid-range) output from the amplifier 135.
  • FIG. 16 there is shown a schematic diagram of the cell power supply 111.
  • the cell voltage is sensed by a pair of operational amplifiers 151, 152 (such as part No. 741).
  • the cell current is supplied by a power driver 154 and is sensed by a series resistance 153.
  • the power driver may have essentially the same construction as the output stage of a direct-coupled audio amplifier, and for cell currents up to about an ampere, an audio amplifier integrated circuit could be used, such as part No. SN76023 or CA3132EM.
  • the operational amplifier 151 compares the cell voltage to the positive threshold V PTH , and when the cell voltage reaches the positive threshold, then the operational amplifier 151 prevents any further rise in the cell voltage by clamping the input to the power driver 154. For this purpose, the output of the operational amplifier 151 is fed back to the input of the power driver 154 through a directional diode 155 and a pnp transistor 156.
  • the pnp transistor is used so that the clamping current can be sensed by a resistor 157 and an npn transistor 158.
  • the output of the npn transistor 158 is level-shifted by a pnp transistor 159 to ground and +Vs (such as 5 volts) to provide a logic signal "V PTH SENSE" that is transmitted by a bus driver 160 to the computer (113 in FIG. 14) to indicate when the cell voltage reaches the positive threshold V PTH .
  • the bus driver 160 is enabled when the computer addresses an address decoder 161 to monitor the status of the power supply 111.
  • the operational amplifier 152 compares the cell voltage to the negative threshold V NTH , and when the cell voltage reaches the negative threshold, then the operational amplifier 152 prevents any further decrease in the cell voltage by clamping the input to the power driver 154.
  • the output of the operational amplifier 152 is fed back to the input of the power driver 154 through a directional diode 162 and an npn transistor 163.
  • the npn transistor 163 is used so that the clamping current can be sensed by a resistor 164 and a pnp transistor 165.
  • Transistor 165 provides a logic signal "V NTH SENSE" that is fed back by the bus driver 160 to the computer (113 in FIG. 14) to indicate when the cell voltage reaches the negative threshold V NTH .
  • the cell current is regulated to a selected value in response to a comparison of the voltage across the current sensing resistor 153 to a set-point value.
  • the computer (113 in FIG. 14) addresses the address decoder 161 to enable a data register 171 to receive a data code indicating a current set-point.
  • the data code is fed to a digital-to-analog converter 172, such as an "R/2R ladder network", that provides a voltage ranging from -Vs to +Vs (for example from -5 volts to + 5 volts) depending on the value of the data code.
  • a code of 00 hexadecimal provides a voltage of -Vs
  • a code of 7F hexadecimal provides a voltage of -Vs/255
  • a code of 80 hexadecimal provides a voltage of +Vs/255
  • a code of FF hexadecimal provides a voltage of +Vs.
  • the output of the digital-to-analog converter is then fed through a variable resistor 173 and a resistor 174 to the negative input of an operational amplifier 190 that compares the control voltage to a voltage indicating the cell current.
  • the voltage indicating the cell current is provided by an operational amplifier 176 that works in conjunction with resistors 177, 178, 179, 180, 181 and 182 to provide a voltage referenced to ground indicating the current through the current sensing resistor 153.
  • the amplifier functions as a differential amplifier to amplify the voltage difference across current sensing resistor 153 without significantly responding to any variation in cell voltage. This condition can be achieved by selecting resistors 177 and 178 to have approximately the same value R 4 , and selecting resistor 181 and the total resistance of resistor 179 and resistor 180 to have the same value R 5 .
  • the gain of the amplifier 176 is set by the ratio R 5 /R 4 , and this ratio should be selected, along with the value of the current sensing resistor 153, so that the output of the amplifier 176 swings within its linear range when the cell current swings over the desired range of cell current.
  • the operational amplifier 190 drives the power driver 154 through a resistor 192 that is needed for the clamping function described above.
  • a capacitor 195 that sets the response time of the amplifier 190.
  • the response time is the product of the capacitance C and the resistance at the negative input of the amplifier 190.
  • the response time for example, is about 15 milliseconds, and it ensures stability of current control by providing a "dominant pole" in the feedback loop consisting of the amplifier 190, the power driver 154, and the amplifier 176.
  • the positive threshold V PTH and the negative threshold V NTH are established by potentiometers 195, 196.
  • these thresholds could be established by respective analog-to-digital converters (not shown) to provide computer adjustment of the thresholds.
  • the power supply circuit in FIG. 16 is calibrated by connecting the power supply cell terminals 197, 198 to a voltmeter 199, an adjustable load resistor 200, and an ammeter 201.
  • the variable resistors 173, 179, 180, 195 and 196 are set to mid-range positions.
  • a data code (such as 80 hexadecimal) is transmitted by the computer (113 in FIG. 14) to the digital-to-analog converter 172 to set a minimum cell current.
  • the load resistor 200 is adjusted to a minimum resistance
  • the resistor 182 is adjusted to obtain a zero current reading by the ammeter 201.
  • the power supply circuit in FIG. 16 is somewhat unusual in that the current sensing resistor 153 does not have one of its terminal connected to ground. This permits independent current sensing to a respective palladium electrode in the battery of cells 100 having the platinum electrodes all connected together to ground, which would be desirable in a power-generating reactor.
  • the fact that the current sensing resistor 153 does not have one of its terminals connected to ground causes some variation in the output of the amplifier 176 with the cell voltage, due to so-called "common mode" signal amplification, unless resistor 180 is adjusted to null out the common mode.
  • CM common mode
  • a data code of 81 hexadecimal (representing -1 mA, assuming 1 mA steps) is transmitted by the computer to the digital-to-analog converter. Then the actual current reading indicated by the ammeter 201 is noted. Next, the load resistance 200 is increased, until the voltmeter 199 reads 2 volts. The current reading indicated by the ammeter 201 is observed, and if it has changed, then the resistor 180 is adjusted to bring the reading back to its original value.
  • the load resistance 200 is set back to a minimum value, and then a data code of FF hexadecimal (representing 127 mA, assuming 1 mA steps) is transmitted by the computer to the digital-to-analog converter 172. Then the resistor 173 is adjusted to obtain precisely the desired full-scale value.
  • the resistor 173 is intended to have a rather narrow adjustment range in order to provide a precise adjustment. If it is desired to obtain a large change in the full-scale value, this should be done by changing the current sensing resistance 153.
  • a switch (not shown) could be provided to select one of a number of precision current sensing resistors (not shown) for different respective current ranges, as is the common practice in power supplies and current measuring instruments.
  • V PTH and V NTH can be adjusted approximately by connecting a voltmeter (not shown) to the taps of the respective potentiometers 195, 196.
  • a more precise adjustment for a particular cell current set-point could be made by transmitting the a code for the current set-point from the computer to the digital-to-analog converter 172, and then increasing the load resistance 200 until the voltage indicated by the voltmeter
  • the potentiometer 195, 196 for the respective threshold can then be adjusted to obtain a desired voltage threshold indication by the voltmeter
  • FIG. 14 can be programmed to automatically perform the method of the present invention upon each of the palladium electrodes in the battery 107 by the transfer of data between the computer and the power supplies 111, 112.
  • the programming includes an executive program
  • an interrupt routine 220 in FIG. 18 that is executed once every minute in response to an interrupt from the real-time clock (118 in FIG. 14), and a routine 230 in FIG. 19 that is called by the interrupt routine once for each cell.
  • the computer clears values for the parameters of each cell. These parameters include the next time that the cell current needs to be updated (CELL_TIME(i)), the step in the cell current cycling schedule that the cell is presently at (INDEX(i)), the temperature of the palladium electrode in the cell (TEMPC(i)), the cell voltage (VOLT(i)), and the cell current set-point (CURRENT(i)).
  • the cell current set-point (of zero mA) is transmitted to each of the cell power supplies.
  • the cell power supplies are energized.
  • each cell power supply 111 (FIG. 16) are powered by the computer, so that when the cell power supplies are turned on, for example by the computer energizing a latching relay, the cell voltage and cell current for each of the cells will initially have zero values.
  • step 204 the value of a variable "BEGIN_TIME" is set to the value of the present time indicated by the real-time clock (118 in FIG. 14).
  • step 205 a cell data matrix is displayed by the computer. This cell data matrix, for example, includes the values of the schedule index, temperatures, voltage, and current set-point for each cell.
  • step 204 the sample timer interrupt is enabled, so that the sample timer interrupt routine 220 of FIG. 18 is periodically executed, for example, once every minute.
  • step 207 the computer operator may enter an
  • the executive program may monitor the performance of the cells , for example , by searching for cells having anomalous temperature excursions, or possibly by monitoring other data collected about the cells, such as data inputted to the computer about analysis of tritium content of the electrolyte in the respective cells, or data inputted to the computer about neutrons or x-rays detected from the respective cells.
  • the computer may formulate a judgement about the performance of the cell.
  • step 210 the computer may attempt to restore the loading of the cell to a high loading ratio, by repeating the cycling schedule for the cell, beginning with discharging of the electrode at the point in the schedule following the initial charging of the cell at a high rate. This is done in step 210 by calling a restoration routine 250 described further below with reference to FIG. 20.
  • step 221 the value of a variable "ELAPSED_TIME" is computed by subtracting the value of the variable "BEGIN_TIME” from the present time indicated by the real-time clock (118 in FIG. 14).
  • step 222 the present time and the elapsed time are recorded in a log file and displayed to the computer operator.
  • step 223 for each cell, the cell parameters are sampled, recorded and displayed. In particular, the cell voltage, cell temperatures, and any indications of the voltage limit thresholds being exceeded, are sampled, recorded and displayed.
  • step 224 the cell current set-point for each cell is recorded and displayed.
  • step 225 the cycle routine 230 of FIG. 19 is called for each cell possibly to update the cell current set-point.
  • step 231 the value of the scheduled current for the index value of the cell is compared to zero to determine whether the cell is being charged. If the cell is being charged, then in step 232 the value of the variable "ELAPSED_TIME" is compared to the value of the cell time for the cell; when the elapsed time is equal to or greater than the cell time for the cell, then the cell current is updated in accordance with the cell current schedule. For this purpose, in step 233 the index for the cell is compared to a predetermined maximum value to determine whether the cycling for the cell has reached the end of the schedule. If not, then the index for the cell is incremented in step 234.
  • step 235 the schedule is indexed with the index for the cell in order to obtain the scheduled cell current set-point, and the cell current set-point is transmitted to the respective power supply for the cell.
  • step 236 the cell time for the next update of the cell current set-point is computed as the sum of the elapsed time and the duration obtained by indexing the cell current schedule with the index for the cell.
  • a cell is advanced immediately to the next step in the cell current schedule when the voltage threshold indicates that a predetermined level of discharging has been achieved at the present level of discharge current.
  • the proper voltage threshold is the positive voltage threshold
  • the logic signal V PTH SENSE from the power supply of the cell indicates whether the positive voltage threshold has been reached.
  • the elapsed time is compared to the cell time for the cell. The elapsed time should not normally be equal to or greater than the cell time for the cell, because the durations for the discharge steps in the cell current schedule should be selected so that the predetermined level of discharging is normally reached before the elapsed time reaches the cell time. Otherwise, as indicated in step 239, the cell is indicated as having a discharge problem, and the cell current is updated in steps 233-236 in accordance with the cell current schedule.
  • step 251 the sample timer interrupt is disabled.
  • step 252 the value of the schedule index for the cell is set to 5, and the current time for the cell is set to the elapsed time.
  • step 253 the sample timer interrupt is enabled. Therefore, at the next sampling time, the index for the cell will be advanced to 6, and the current set-point for the cell will be updated to begin discharging the cell at a high rate.

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Abstract

Un isotope de l'hydrogène est chargé électroniquement dans une électrode de palladium ou en alliage de palladium (22) en chargeant et en déchargeant alternativement l'électrode en plusieurs cycles, chaque cycle incluant le chargement de l'électrode avec un isotope de l'hydrogène à peu près jusqu'au niveau de saturation puis à décharger l'électrode jusqu'à un niveau de rétention prédéterminée. L'électrode peut être palladisée par électrodéposition d'une mince couche de noir de palladium, puis préchargée dans un gaz de deutérium à la pression atmosphérique, avant d'être transférée dans une cellule électrochimique (20) dans laquelle les opérations alternées de chargement et de déchargement s'effectuent au total quatre à cinq fois.
PCT/US1992/005717 1991-07-11 1992-07-08 Methode de reproduction constante d'une charge elevee de deuterium et d'obtention de tritium dans des electrodes de palladium WO1993001601A1 (fr)

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Publication number Priority date Publication date Assignee Title
EP0576293A1 (fr) * 1992-06-26 1993-12-29 Quantum Nucleonics Corp. Production d'énergie par commande des probabilités d'effets quantiques, réalisé par l'intermédiaire d'interactions induites de niveaux quantiques
WO2019070789A1 (fr) * 2017-10-04 2019-04-11 Ih Ip Holdings Limited Réacteur nucléaire in situ
CN110831895A (zh) * 2017-03-29 2020-02-21 艾合知识产权控股有限公司 在高氢加载速率条件下触发放热反应

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CN110831895A (zh) * 2017-03-29 2020-02-21 艾合知识产权控股有限公司 在高氢加载速率条件下触发放热反应
WO2019070789A1 (fr) * 2017-10-04 2019-04-11 Ih Ip Holdings Limited Réacteur nucléaire in situ

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