Hydrogen triggered exothermal reaction in uranium metal

Transcription

1 Dufour, J., et al., Hydrogen triggered exotermic reaction in uranium metal. Pys. Lett. A, : p Hydrogen triggered exotermal reaction in uranium metal J. Dufour, D. Murat, X. Dufour, J. Foos CNAM, Laboratoire des sciences nucléaires, 2 rue Conte, Paris, France Received 3 November 999; accepted 28 April 2000 Communicated by J.P. Vigier Abstract An exotermal reaction as been observed wen submitting metallic uranium to te combined action of a magnetic field and an electrical current. e set-up used to study te penomenon is described and results are given. A tentative explanation is given, based on te possible existence of a still ypotetical proton/electron resonance. Keywords: ranium; Magnetic field; Electrical current; Exotermal nuclear reaction; Proton/electron resonance. Introduction We report ere results obtained by submitting uranium metal to te combined action of a pulsed electrical current and a magnetic field. We ave observed wat seems to be an exotermal reaction occurring in te uranium. e magnitude of te exotermicity observed is too ig to be explained by any known cemical reaction. We tus present a tentative explanation based on a ypotetical - and purely electromagnetic - resonance proton/electron tat could catalyze certain nuclear reactions of te uranium nuclides. e protons involved are initially present in te uranium metal we use. e manufacturer indicate an ydrogen content from 3 to 0 ppm weigt (metal obtained by magnesium reduction of te oxide). is ydrogen content is a common value for uranium prepared using tis metod []. is tentative explanation is substantiated by te first indications given by te mass spectrometry analysis of te uranium samples obtained in te preliminary experiments. 2. Experimental strategy Preliminary simplified calorimetric experiments (experiment placed in a box excanging eat wit te air of te laboratory kept at 25 C, eat flux measured by te temperature of te uranium metal), ad given indications of an exotermal reaction occurring in te metal. Wen certain types of currents (pulsed currents) were passed troug it and a magnetic field was simultaneously applied, more termal energy was recovered tan electrical energy was put in. e analysis of te treated uranium samples compared to te virgin ones sowed te apparition of a significant amount of lead. Moreover, by monitoring te gamma activity of te samples during and after treatment, we observed no important variation of tis activity [2].

2 Given tese preliminary results, we tougt it was wort looking more in details into tis reaction. e strategy we decided to follow as two steps: first: improve te calorimetry and master te conditions under wic te penomenon occurs second: analyze te treated uranium samples by mass spectrometry (including isotopic ratios) to confirm te apparition of lead we observed in te preliminary experiments, monitor te gamma activity of tese samples and test various oter metals to compare teir beavior to tat of uranium. In parallel, we ave tried to find a plausible, but still ypotetical, explanation for te penomenon. We ave now acieved te first step. We are going to describe te experimental set-up and report te results it yields. We sall also present te ypotetical explanation we propose. Before tat, a brief summary of te preliminary experiments will be given. 3. Summary of te main results of te preliminary experiments 3.. ermal effect ranium samples (turnings of natural uranium metal) were pressed in a small reactor between two steel electrodes (2 to 6 mm diameter, 0 mm long), temselves placed between two permanent magnets of comparable diameter (remanence around ). e reactor was placed in a tigt aluminum box, kept under argon atmospere and could be eated to te required temperature by a resistor. e eat flux was monitored by te measurement of te reactor temperature. ree preliminary experiments yielded te results summarized in able wen a pulsed current was passed troug te uranium. able Results of preliminary experiments Experiment A B C Mean power due to te reaction (W) otal energy of reaction during te experiment (kj) Reactor temperature ( C) C 200 C 70 C ranium weigt (mg) Energy of reaction from processed (MJ/mole ) Pulsed current intensity (A) 6 to 0 ( oxidation) 5 3

3 able 2 Results Experiment Ref. Ref. A B C Pb content (ppm) Energy of reaction per atom Pb produced (MeV/ Pb atom) 3.2. Mass spectrometry analysis ranium samples were dissolved in two steps: uranium react wit ydrocloric acid rapidly to form uranium (IV) cloride and a black precipitate of ydrated uranium (III- IV) oxide. Hydrogen peroxide is ten added to te solution for a complete dissolution of te precipitate to obtain a clear uranyl cloride solution [3]. e samples were analyzed by ICP-MS. Reference samples exibit very low lead quantity, wereas samples tat ad been treated wit pulsed current under a magnetic field (sample A, B and C) exibit a muc iger lead quantity. Combining tese results wit tose obtained in te calorimetric measurements yields te able 2. It is clear from ables and 2 tat no cemical reaction involving te uranium can explain te observed difference between te energy input and te energy output and tat tis difference per atom of lead produced point towards a nuclear reaction involving te uranium nuclei Gamma potons registration Gamma potons emitted by te uranium samples during and after treatment were registered (Ortec germanium detector). We only observed small variations of te samples total activity (up to plus or minus 0% of te initial total activity). Most of te variations are observed on te peaks of te first daugter of te 238 : 234. ese variations are well above background fluctuations. ey are neverteless ardly compatible wit an acceleration of te well known deactivation route leading from 238 to 206 Pb, acceleration wic could explain te calorimetric results and te lead level we observe (te gamma activity would tremendously increase). is point will be dealt wit later. 4. Principle of te improved calorimetric measurements now in use e observation of te penomenon was done in te following conditions: uranium metal at relatively ig temperature 200 C witout oxidation experiment of several days a sufficient amount of uranium more tan 500 mg in order to allow subsequent analysis of te sample by mass spectrometry te passage of a ig electrical current: 5 A te presence of a ig magnetic field: tesla is precludes te use of classical calorimetric metods as for instance currently available Calvet or Seebeck calorimeters (weter te total eat flux is measured by termocouples or by te Seebeck effect of a semiconductor). e experiment indeed requires a minimum volume of 500 cm 3 and we do not ave suc equipment in te lab.

4 We ave tus been compelled to develop an alternative approac, adapted to te required conditions for te penomenon to be observed and presenting a sufficient degree of reliability. e principle of te calorimetric measurement is to compare te termal effect of a pulsed current versus te termal effect of a direct current. Fig. is a description of te overall experimental set-up. Fig.. Description of te experimental set up. 4.. Principle and description of te electrical measurements We need to measure te electrical power P tat is dissipated in our experimental device. P 0 u t it dt I, were and I are te root-mean-square (rms) values of te tension and te intensity. P I if tere is only pure resistance in our experimental device. I appears to be an upper limit of te dissipated power. We decided to neglect any possible nonresistive component of our experimental device. us, te dissipated power we consider is a maximum value of te real dissipated power.

5 Fig. 2. Sape of te pulsed current. e AOIP SA multi-cannel data acquisition system we use is designed to measure te tension (or te intensity) of a direct current. Wit a pulsed current (Fig. 2) te given value is te mean one: t t u 0 d were is te integration time ( = 40 ms i.e. about 700 signal periods)., () t t u 0 2 d, (2) From Eqs. () and (2) we ave (3) and I I (4) us I P (5)

6 f=( + )/ is a factor, wic depends on te sape of te pulsed current. In order to access tis sape factor, we measure te termal flux out of a tin film non-inductive resistor in line wit te experimental device. e resistor was put in a cubic aluminum box. On eac side of te box tere is a termoelectric generator tat utilizes Seebeck effect. e six termoelectric generators are in line and we measure te voltage V Seebeck. is simple calorimeter is calibrated wit direct current, we obtain a correlation V A I. en we infer te sape factor f from te response of tis Seebeck B r DC calorimeter, from te measured current. r te resistor voltage and from I wen we use a pulsed 4.2. Description of te experimental device A DC electrical generator delivers electrical power into a reactor containing te uranium metal. e electrical power is delivered eiter in te form of constant direct current, troug connection OB or in te form of pulsed current troug connection OA. e pulsed current is saped by te action of a transistor (International Rectifier Power MOFSE type IRL 3803), wic is triggered by a function generator (Metrix GX 245) (Fig. ). Natural uranium metal turnings (3 mm widt, 0. to 0.3 mm tick and cut into pieces of about 0 mm lengt) are placed between two cylindrical iron electrodes (6 mm diameter), according to Fig. 3. e first electrode is 9 mm long and te second 22 mm (central electrode, wit a 0 mm ole in its center). A tird electrode, identical to te first one is placed in contact wit te central electrode. wo wires are fixed by solder on electrodes and 3, allowing electrical current to be passed troug electrode, te uranium turnings, te central electrode and electrode 3. ree wires allow te measure of and RE. wo identical magnets (0 mm lengt, 5 mm diameter are placed in contact wit electrodes and 3 in suc a way tat tey generate, troug te uranium and te electrodes, a magnetic field parallel to te axis of te electrodes. ey are made from cobalt/samarium, ave a magnetic remanence of and can witstand 300 C witout loosing teir magnetism. ree temperature sensors (Pt 00) are placed in te central electrode: two at eac ends, in two 3 mm diameter oles bored at 4 mm from te two edges of tis electrode, and one in te central, 0 mm diameter ole and measure respectively (temperature of te uranium side), RE (temperature of te reference resistor side) and reg (regulation of te temperature level of te experiment).

7 Fig. 3. Reactor. e tree electrodes and te two magnets are enclosed in two identical aluminum cylinders acting as a regulated eater (see Fig. 4). Eac cylinder is 50 mm diameter and 40 mm long. A ole in te cylinders allows te exit of te wires connected to te electrodes. Four eating cartridges 76 mm long and 6.3 mm diameter (RS component) are introduced in four oles bored troug te aluminum cylinders and eat tem in a regulated way (Auto-tune temperature controller CAL 9400, delivering electrical power to te eating cartridges from a DC generator on a zero/full power basis). e two aluminum cylinders are pressed against te ends of bot magnets by te action of four bolts, parallel to te four eating cartridges (and not represented in Fig. 4). e wole assembly is finally placed in a vacuum tigt aluminum box, equipped wit te required passages for te wires conducting te current to te reactor and tose connecting te various sensors to te AOIP SA multi-cannel data acquisition system tat monitors te experiment. e box is kept under vacuum (5 to 0 Pa) by te action of a vacuum pump. nder tese conditions, te oxidation of te uranium sample is controlled at a very low rate for periods of several days and temperatures of te eater up to 200 C. e differential power measurement device functions as follows: te temperature of te eater is set at a given value reg (generally around 200 C). Preliminary measurements ave sown tat RE varies slowly wen increasing reg from ambient to 70 C and remains constant above 70 C up to 220 C. Let 0 be te value of Δ wen te eater as reaced its preset value reg. e mean power dissipated by te eater to maintain reg at 200 C is typically around 60 W.

8 a direct current is ten passed troug te tree electrodes. e resistance R of te contacts steel / uranium turnings / steel is typically between 5 and 5 mω and te corresponding resistance R RE of te reference contact resistance steel / steel between 2 and 5 mω. e Joule power W I f I on te uranium side is tus iger tan te Joule power W RE 0 I f I on te reference side and Δ increases. e intensity of te direct (or pulsed) current we use is limited to 5 A. e power injected in te electrode system is tus limited to less tan 6 W, wic is a small fraction of te power required to maintain te eater at 200 C. e joule effect is tus a perturbation of te total eating and te is a linear function of te difference relative temperature difference 0 P W W RE : RE RE K P 0 (6) K is essentially determined by te geometry of te electrodes and by teir termal conduction properties (te experiment being under vacuum, te main eat transfer mecanism is conduction). is relation as been cecked experimentally to be very accurate. If an exotermal reaction, yielding a power P E, takes place in te uranium, relation (6) is no longer valid and is replaced by: K P 0. (7) P E We measure K wen passing direct currents of various intensities in te electrodes. In all our experiments, we ave observed tat wen plotting ΔP versus 0 we obtain a very good linear relation: P K 0. (8) If we switc to pulsed currents (witout canging te experimental set-up) te points obtained are systematically on te rigt side of tis straigt line as explain on te sceme Fig. 5. We can calculate P E from te measurements of W, W RE and 0 wen passing te pulsed current and te correlation obtained wen passing te direct current: P Ppulse E K 0. (9) Remark. wo second order corrections ave to be taken into account to get precise measurements: Due to small modifications in te eating power of te cartridges, we observe a small and continuous drift of 0 during te course of an experiment (0.03 to 0.07 K/day). We measure tis drift and accordingly correct te temperature differences. Bot resistance R and R RE vary slowly wit time. Wen tis variation is too fast, 0 is somewat lagging beind ΔP, resulting wen ΔP increases during te calibration wit direct current, in an under estimation of te power injected

9 given by (8). In order to be on te safe side, we eliminate tese points from correlation (8), wic represent 5 to 0% of te points. Fig. 4. Reactor eating system. Fig. 5. P versus Δ-(Δ) Experimental results We report ere te results of an experiment run wit uranium. 788 mg of uranium turnings were placed in te reactor and te experiment was run according to te following protocol. 5.. Experimental protocol

10 e following operations are run in sequence. Measurement of 0. e eater is eated at four temperatures ( Reg = 70, 90, 200 and 20 C), to ceck te absence of variation of 0 wit Reg. 0 is taken at te temperature of te experiment (around 200 C). Duration 24. e temperature of te reactor is ten set at Reg = 200 C. Calibration of te sape factor measurement device. A direct current (tree intensities: 5, 0 and 5 A) is passed troug te experimental set-up (Fig. 2, contact OB closed). Duration 36. is yields a relation (0) between r I and V Seebeck. A linear relation gives a correlation coefficient iger tan 99%. V Seebeck A I B r DC Establisment of te relation between ΔP and 0 DC (0) wen a direct current is passed troug te metal under test (baseline of te experiment). is is done at te same time as te calibration of te sape factor measurement device and yields relation (3). A linear relation gives a correlation coefficient iger tan 99%. Determination of te drift of 0 wit time. e DC current is cut and 0 Determination of te drift of 0 is measured at Reg = 200 C Effect of te pulsed current on te metal under test. e contact OB is switc to OA and kept in tis position for several days. wit time. e pulsed current is cut and 0 is measured at Reg = 200 C. Back-cecking of relation (3) and (0). e direct current is switced on again (contact OB closed) and various intensities are passed troug te experimental device to yield an f factor calibration curve and a baseline of te experiment extending on bot sides of te results obtained wit te pulsed current (see below). Determination of te drift of 0 0 is measured at Reg = 200 C Presentation of te results wit time. e DC current is cut-off and Fig. 6 sows ow te measured ΔP varies as a function of te 0 measured. For direct current, te experimental points fall (wit a correlation coefficient better tan 0.99) on a straigt line. e corresponding coefficient K - of relation (3) is 989 mwk -. e situation is different wen pulsed current is passed troug te uranium. All points fall on te rigt side of correlation (3), indicating tat te power P E of an exotermal reaction occurring in te uranium is added to te power generated by te Joule effect in it. We can ten use relation (9) to calculate P E and consider its evolution wit time. Fig. 7 sows tis evolution. It can be seen from tis grap tat:

11 P E is about zero (mean value 0 mw, standard deviation 5 mw), wen a direct current is passed troug te uranium (before and after te pulsed current is passed troug it). P E is continuously increasing from some 50 mw to nearly 900 mw, wen a pulsed current is passed troug te uranium sample. Fig. 6. Experimental results (P versus Δ - (Δ) 0 ). Fig. 7. Experimental results (P E and R versus time).

12 5.3. Discussion of te results We now discuss some possible trivial explanations of tese results: Effect of te sape factor f. We find for relation (0) te following coefficients: A = 0.5 mv/w and B = 2.9 mv. From tese values, we can calculate te sape factor as V Seebeck measured V Seebeck from(0) f. Over te wole duration of te experiment, te following mean values were obtained f =.00 (standard deviation 0.004) for te periods wen direct current was passed and f =.30 (standard deviation 0.009) wen pulsed current was passed. From tese figures, we can conclude tat te properties of te transistor tat sapes te pulsed current ave not varied significantly during te experiment. Moreover, te sape factor f is very close to te teoretical one (.29) calculated from te and used in tis experiment. e variations of f are tus second order, wereas te ratio P E (W +W RE ) is continuously increasing from 0 to 28% during te experiment (as can be seen in Fig. 8). is second order variation cannot tus account for tis result. effect of te variations of te resistance of te uranium. As can be seen in Fig. 7, te resistance of te uranium as varied during te experiment. Periods of stability of tis parameter are found for instance between day 3 and day 4, wen P E continuously increased. is increase cannot tus be attributed to te lagging of 0 beind ΔP. In te period day 2 to day 3, te resistance of te uranium as increased twice abruptly. It can be seen in Fig. 7 tat P E as also increased sarply but as come back to te general trend of P E after te subsequent decrease of te resistance. From tese considerations, we conclude tat no trivial explanation can account for te observed value of P E. is value is of an order of magnitude comparable to wat we observed in our preliminary experiments and justifies te strategy we ave cosen.

13 Fig. 8. Experimental results (P E /(W + W RE ) versus time). 6. A possible and ypotetical explanation of tese results We give ere a possible but still ypotetical explanation of te penomenon we observe and tis for two reasons: we use tis explanation as a guideline for our experiments. it migt tus elp te reader to understand our approac. We assume te possibility of te existence of a resonance between a proton and an electron, yielding a particle of almost nuclear dimensions (a few fm) and we examine te possible consequences of te existence of suc a particle. e ydrogen atom is one of te best known objects of pysics and its properties can be completely calculated up to te tird order interactions (ydrogen yperfine structure). is last interaction results from te effect of potentials, wic are very strong at very sort distances of te electron from te proton, but are only tird order wen averaged on te wole volume of te atom (magnetic interactions between te proton and te electron, described by te yperfine structure Hamiltonian). e question as been raised [4,5] weter tis interaction could yield a muc smaller object tan te known ydrogen atom. In suc an object, it would of course be first order on te wole interaction volume. A quantum electrodynamics calculation was performed on te proton/electron system [6,7], pointing to te possibility of te existence of a resonance (life time of a few seconds, dimensions of a few fm and an endotermic energy of formation of a few ev). is resonance as been proposed to explain some ypotetical nuclear reactions [8,9]. We assume te existence of tis resonance (wic for simplicity of language we propose to call ydrex: H ~. We guess some of its properties and use tem to improve its

14 syntesis and explain ow it could act on nuclei to catalyze certain classes of nuclear reactions. 6.. Main properties of ydrex tat can reasonably be imagined e magnetic moment of te electron sould ave te same direction as te nuclear moment of te proton (probably parallel in te ground state and antiparallel in excited states). Hydrex can be polarized in te ig electrical field of a big nucleus (it could even be a small permanent electrical dipole) How do we try to improve te syntesis of ydrex We start from protons enclosed in a dense medium (metallic ydrides were tey ave a ig mobility) and favor teir collisions wit te conduction electrons by passing an electrical current troug te ydride. As we tink tat tese collisions are more efficient to form ydrex if te magnetic moments of te two particles ave te same direction (weter tey are parallel or antiparallel) we apply to te metallic ydride a magnetic field (of intensity as ig as possible) aving te same direction as te current. Note tat contrary to te situation in vacuum, te protons and te electrons are submitted to potentials due to te lattice tat could also favor te formation of ydrex How ydrex, wen formed, could catalyze certain nuclear reactions Hydrex as we imagine it, is an electric dipole wit almost nuclear dimensions. It can tus be attracted by a uranium nucleus. Peraps, one uranium nucleus and several ydrex could form a cluster, wit a lifetime on te order of seconds, wic is considerably iger tan typical nuclear time (0-22 s). us, in tis nuclear cluster, unusual nuclear reactions could take place. Let us now examine two of tem: Hydrex assisted α emission: te presence of several polarized ydrex in contact wit an uranium nucleus can modify its Coulomb barrier. Simple calculations, using a layer model, ave sown tat te initial barrier (eigt 32 MeV, tickness some 50 fm) could be split into two barriers: a first one close to te uranium nucleus wit same eigt, but muc tinner (some 5 fm), followed, after a potential well, by a second one of smaller eigt (5 to 7 MeV) and tickness 35 fm (te level of te potential well depends on te number of ydrex in te cluster). Since te works of Gamow, Gurney and Condon in 928, it as been well known tat te probability of alpa emission of a nucleus can vary considerably wit small variations of te eigt and tickness of te Coulomb barrier [0]. We tus tink tat te rate of alpa emission of te 238 can be considerably increased in our experiment due to te formation of te ydrex/uranium clusters [2]. ω emission of te uranium: tis is a reaction wit no classical equivalent, tat could explain te absence of tremendous increase of te β - emission tat sould be observed after an increase of te rate of te α emission. e first daugter of 238 is 234, wic decays into 234 Pa troug β - emission (/2 life time 24 days). In te ydrex/uranium cluster, 2 neutrons of te uranium could react wit 2 ydrex, to yield 232 and 4 He according to te reaction:

15 H ~ ω He 7.3 MeV (ω emission) 234 e combination of tese 2 types of reactions could give a route from uranium to lead witout β - emission. 7. Perspectives and conclusion e improved calorimetric device tat we ave developed confirms our preliminary experiments. e level of te power liberated in te uranium by te exotermal reaction tat we measure wit te new device compares well wit wat we found previously: 0.9 W versus 3.8, 0.8 and.2 W. Moreover, te oxidation of te uranium can be controlled, provided te vacuum of te experiment is of good quality. We tus ave planned a series of experiments to: measure te lead content of te uranium after treatment (including isotopic ratio) and compare tis level wit te energy liberated by te exotermic reaction. test oter metals to see if similar penomenon are observed wit tem. References. P. Pascal, in: Nouveau traité de cimie minérale, ome XV, Masson, Paris, France, p J.J. Dufour, J.H. Foos, X.J.C. Dufour, ICCF7 Proa, ENECO, Salt Lake City, SA, pp R.P. Larsen, Anal. Cem. 3 (959) A.O. Barut, J. Kraus, J. Mat. Pys. 7 (976) A.O. Barut, G. Craig, Pysica A 97 (993) J.R. Spence, J.P. Vary, Pys. Lett. B 254 (99). 7. J.R. Spence, J.P. Vary, Pys. Lett. B 27 (99) F.J. Mayer, J.R. Reitz, Fusion ecnology 20 (99) R. Antanasijevic, I. Lakicevic, Z. Marie, D. Zevic, A. Zaric, J.P. Vigier, Pys. Lett. A 80 (993) J. Foos, in: Manuel de radioactivité à l usage des utilisateurs, Formascience, Orsay, France, pp