Transmutation Reactions in Condensed Matter - American Chemical

Chapter 12

Transmutation Reactions in Condensed Matter

Downloaded by PENNSYLVANIA STATE UNIV on July 1, 2012 | http://pubs.acs.org Publication Date: August 1, 2008 | doi: 10.1021/bk-2008-0998.ch012

Tadahiko Mizuno Laboratory of Nuclear and Environmental Materials, Graduate School of Engineering, Hokkaido University, Kita-ku, North 13, West 8, Sapporo 060-8628, Japan

The appearance of many elements on palladium electrodes after long-duration electrolysis in heavy water at high pressure, high temperature, and large current density was confirmed by several analytic methods. Mass numbers as high as 208 corresponding to elements ranging from hydrogen to lead were found, and the isotopic distributions of many of these elements were radically different from the naturally occurring ones. Changes in element distribution and in their isotopic abundances took place during electrolysis in both heavy and light water, whether or not excess energy was generated. If the transmutation mechanism can be understood, it may then be possible to control the reaction, and perhaps produce macroscopic quantities of rare elements by this method. In the distant future, industrial scale production of rare elements might become possible, and this would help alleviate material shortages worldwide.

Introduction Many people have asserted that if nuclear reactions are induced by electrochemical reactions using solid electrodes there should also appear clear evidence of the generation of radioisotopes and of radiation. Moreover, the evolution rates of reaction products should be able to be quantitatively explained in terms of well-established nuclear reaction mechanisms, but this expectation would be valid only if the reaction mechanism is in accord with accepted nuclear theory. However, there is little reason to believe that a conventional mechanism applies to the nuclear reactions accompanying electrolysis. Hence, © 2008 American Chemical Society In Low-Energy Nuclear Reactions Sourcebook; Marwan, J., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2008.

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the expected emission of radiation and radioisotopes may not occur. This work presents evidence that a nuclear reaction takes place during electrolysis that produces isotopically changed elements on the cathode surface. These elements are generated by a mechanism that does not induce any detectable radiation. The anomalous isotopic abundances of these elements show that they do not come from contamination. We suggest that the operative nuclear mechanism is completely different from any known nuclear reaction. Mizuno (/), Miley (2), Ohmori (3), Iwamura (4), and others have reported anomalous production of radiation-less foreign elements (Fe, Cr, Ti, Ca, Cu, Zn, Si, and so on) on cathode metals (mainly Pd) with heavy water or light water electrolysis experiments. These elements sometimes have drastically non-natural isotopic ratios.

Experimental Sample

The experimental details of the sample, cell, electrolysis, and the reaction conditions have been described elsewhere (5). After the Teflon coat of the sample electrodes was removed and the samples were washed in the Mill Q water, they were analyzed by means of energy dispersive X-ray spectroscopy (EDX), Auger electron spectroscopy (AES), secondary ion mass spectroscopy (SIMS), electron probe micro analyzer (ΕΡΜΑ), and inductively coupled plasma (ICP) spectrometry. Palladium rods used were of high purity (99.97% min.) supplied by Tanaka Noble Metals, Ltd. Impurities in the rods were as follows: B: 110, Si: 10, Ca: 9, Cr: 8, Cu: 6. Ti: 5, Ag: 41, Pt: 16, and Au: 23 ppm. Nothing more was detected by ICP measurement. The palladium rod was held in a vacuum of 5*10' Torr at 473 Κ for 6x10 sec. Showa Denko, Ltd. supplied heavy water. It is 99.75% pure and includes 0.077 micro Ci/dm of tritium. The heavy and light water were purified once in a quartz glass distiller. Reagent grade lithium hydroxide was obtained from Merck, Ltd. Impurities in the reagent were specified as follows: L i C 0 : 2% max, CI: 0.05%, Pb: 16, Ca: 154, Fe: 13, K: 156, and Na: 135 ppm. Other impurities were under detectable limit by ICP analysis. The anode was a Pt plate and the recombiner catalyst was a Pt mesh, both high purity (99.99%). The Pt metal is specified to contain impurities as follows: Rh: 18 ppm, Si, Cr, and Pd: 2 ppm, Au, Ag, B, Ca, Cu, and Fe: less than one ppm. And other impurities were under detectable limits of ICP analysis. 5

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Electrolysis

All electrolysis was performed in a closed cell made from a stainless steel cylinder. The cell has an inner Teflon cell made with a 1-mm thick

In Low-Energy Nuclear Reactions Sourcebook; Marwan, J., et al.; ACS Symposium Series; American Chemical Society: Washington, DC, 2008.

273 wall and a 1-cm thick upper cap; the inner height and diameter are 20 cm and 7 cm, the volume is 770 cm (Figure 1). Further details have been described elsewhere (6, 7). Before electrolysis, 400 cm of electrolyte were pre-electrolyzed using another Pt mesh electrode at 1 A and 150°C for 7 days in the closed cell. After that the Pt electrode was removed and the palladium rod sample was connected to the electrical terminal. Electrolysis experiments were performed with the current density of 0.2 A/cm or total current of 6.6 A (33 cm χ 0.2 A/cm ) for 32 days at 105°C. Typical time variations of current, temperature, and D/Pd ratio during electrolysis in heavy water solution are shown in Figure 2. In the experiment shown here, some excess heat was generated after electrolysis, as indicated by the temperature rise of the electrolyte after the electrolysis was stopped at 766 hours. The phenomenon is very anomalous since the temperature would be expected to decrease after shutting off the input power. All electrolysis was carried out at 0.2 A/cm or a total current of 6.6 A (33 cm χ 0.2 A/cm ) for 2.59 χ 10 s (30 days) at around 100°C. 3

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Figure 1. Photo of cell. The upper portion shows the cell cylinder and Pt recombiner. The lower portion shows the anode, cathode, pressure gauge, temperature sensor, and relief valve. Element Analysis After electrolysis the palladium rod was washed with Mill-Q water (Japan Millipore Ltd., model MillQ-lab) and covered by a Teflon tube. The analysis samples were prepared by cutting the rod into 1 cm segments with a diamond cutter, and then cutting the segments lengthwise into two semicircular-shaped masses. The sample electrode was removed from the Teflon coat, washed with


274 împerature

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100 200 300 400 500 600 700 800 900 Time/hour

Figure 2. Changes of temperature, pressure, and D/Pd ratio during electrolysis.

Mill-Q water again, and analyzed with EDX, ΕΡΜΑ, AES, and ICP spectrometry, performed by the author. SIMS analysis was performed by Hitachi Measurement Engineering Co., Ltd., Ibaraki Laboratory (Hitachinaka City, Ibaraki prefecture), and Nissan Ark Co., Ltd. (Yokosuka City, Kanagawa prefecture). EDX measurements were done with 20 keV electron irradiation, with variation of the scanning area. The energy spectra were measured with a siliconlithium drift detector. The energy range of analysis was zero to 20 keV; the interesting range was divided into 1024 channels of energy width. The energy resolution was 150 eV at 5.9 keV, but for practical purposes it was 200 eV. Peaks were calibrated using high purity samples of C, A l , Si, Ti, Cr, Mn, Fe, Co, Zn, Sr, Nb, Mo, Pd, Ag, Sn, Ce, Hf, W, Pt, Au, and Pb. AES (ANELVA model AAS-200) analyses were performed to obtain the depth distribution of the elements; the ion irradiation energy and the current were 3 keV and 2.5 A , respectively. An ΕΡΜΑ (Shimadzu Ltd. Model EPMA-8705) was used to obtain the elemental distribution on the samples. SIMS measurements (Hitachi Co. model IMA-3000) were made, with 0 ions targeted onto the sample at a spot of 400 square micrometers, with primary energy of 10.5 keV and 100 nano Amperes ion current. Resolution for the mass measurement was m/e=10000. Mass numbers were calibrated with high-purity metals including L i , B, C, A l , Si, Ca, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Nb, Mo, Pd, Ag, Cd, Sn, Ce, Hf, W, Os, Pt, Au, and Pb. No isotopic changes over the natural deviations were noted in the calibration measurements. Careful estimations of the abundance of each element +

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were required because many mass peaks due to molecules, oxides, hydrides, and other complex materials interfere. We used various analytic methods to obtain precise isotopic abundance. ΕΡΜΑ analysis was used first to estimate the element's distribution on the sample. AES was employed to obtain the depth distribution of certain elements and EDX measurements determined the relative concentrations of various elements. These techniques were used complementarily because any one method could not necessarily be applicable to all of the elements. In later studies, the SIMS technique was adopted to determine the elemental abundances at various points on the sample surface. The entire palladium surface was dissolved in hydrofluoric acid and the solution was analyzed by ICP. The total atomic concentration was estimated.

Results Many elements were deposited on the electrode surface in an irregular distribution. The concentrations varied depending on the parameters of the electrolysis. The elements that have been detected on the samples were C, O, S, CI, Si, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Mo, Pd, Sn, Pt, Hg, and Pb. The amount of each element varied by the sample lots. This may mean that some factors such as surface conditions play an important role in the reaction. Several elements were also detected in the palladium sample by the EDX and ICP method; the measurements were taken to determine the rough level of concentration of the elements because mass peaks in the SIMS measurement can include signals from other molecular peaks. Figure 3 shows a typical EDX spectrum for a sample that was electrolyzed in heavy water solution and evolved some excess heat (1.2 χ 10 J) (/) after electrolysis. It shows data from before and after electrolysis. Several peaks of Pt, Cr, and Fe are clearly seen; these amounts were comparable to the Pd bulk peak. Smaller amounts of Sn, Ti, Cu, and Pb are also clearly observed. The EDX analyses were repeated at various locations on the sample surface; the EDX counts sometimes varied by as much as a factor of ten depending on the location. In the last stage of the analysis, the mass abundance for the elements was measured by SIMS. The EDX, AES, and ΕΡΜΑ methods were complimentarily used to attribute mass spectra to specific atoms and to determine isotopic distributions. The following procedure was used: 7

1. The mass numbers were establishedfirstfor light to heavy mass number. 2. The mass numbers were confirmed by referring to the EDX and AES spectra. 3. The large count number of mass peaks was used to confirm the existence of their molecular ion and oxide ion peaks.



0

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Energy/keV

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Figure 3. EDX spectrum of the Pd electrode surface electrolyzed in heavy water solution.

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The final mass spectra were estimated by applying the relative sensitivity factor (rsf) to the original count of mass depending on the element composition. This factor changes from high to low values for the inert gases and alkali metals when 0 ion bombardment is used. +


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The atomic concentration on the palladium surface was estimated by the ICP method. Figure 4 shows the typical concentration in a 10 micrometer layer of the sample. Two values are shown, for before and after electrolysis that produced excess heat. Impurities before the experiment were as follows, where the Pd concentration is normalized at 100: B: 0.0012, Si: 0.001, Cr: 0.001, Fe: 0.0015, Pd: 100.0, Ag: 0.0040, Pt: 0.002, and Au: 0.0025. The total element concentration after electrolysis was: C: 100, O: 120, Si: 15, P: 7.5, S: 17, Ca: 3, Cr: 18, Fe: 7.5, Cu: 12, Zn: 37, Pd: 100.0, Xe: 1000, Pt: 0.9, Pb: 0.4. Based on this, it seems that the detected elements are distributed in atomic numbers close to those of the impurity elements that originally existed in the cell. The total amount of the elements existing at a one-micrometer depth in the palladium surface were calculated as follows: C: 0.40, O: 8.84, Si: 0.15, S: 0.17, CI: 0.06, Ca: 0.142, Ti: 0.76, Cr: 22.96, Fe: 10.06, Cu: 5.61, Zn: 3.35, Pd: 33.45, Pt: 9.65, Pb: 4.39, and others were less than 0.005 atomic percentage. It should be stressed that the total amount of deposited elements on the palladium is much higher than the total impurity in the electrolyte and palladium

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Transmutation Reactions in Condensed Matter - American Chemical

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