METHOD FOR SYSTEMATIC TRANSFORMATION OF NUCLIDES

Method for systematic transformation of nuclides

The invention relates to a comprehensive atomic/nuclear shell model ( the Galactic Trinity Model = G.T.M. ),which is applied in relation with a Periodic System of Atoms = P.S.A.) as a basic method in nuclear physics and nuclear technology for the systematic planning, calculation,preparation, execution and assessment of nuclear transformations. The method is applicable for the production of nuclear energy, the production of usefull nuclides and the transformation of hazardous radioactive wastes. Assessment of the background art

A comprehensive, generally appliahle model of nuclear structure has not been available thus far for the further development of nuclear physics and nuclear technology. Much work is based on partial theories and trial and error procedures due to a lack of understanding of the fundamental structure of the atomic nucleus. This results in insufficient progress in. three fields: 1) nuclear energy production; 2)methods for the production of beneficial nuclides for applications in science and techno logy;and 3) treatment, storage and disposal of radioactive wastes.

The availability of a comprehensive, theoretically-based model which should account for the wide spectrum of experimental data could improve the situation drastically by leading to a well-defined, problem-oriented and highly-efficient use of the presently uncoherent complex of experimental and theoretical knowledge, manpower and nuclear facilities like reactors and accelerators.

The invention deals partly with the same subjects as described in patent applications by Verschraegen (GB-A-802971 ) ,Schikarsky (DE-A-2249429),Marriot et.al. (EP-A-0030404), and Keiss (EP-A-1-0099946), which deal with methods to transform radioactive wastes, or in the last case also with the production of nuclear energy. In all cases,however, their methods are based on the present, partly inadequate understanding of nuclear structure and the conventional nuclear shellmodel by Mayer and Jensen. The lack of a systematic, comprehensive nuclear model - as evident from the recent compilation by L. Valentin: Subatomic physics:Nuclei and particles. Vol. 1 and 2,600 pp.,North Holland Publ. Co. Amsterdam, 1981 ,leads in all cases mentioned to a more empirical approach,without the possibility of a systematic appraisal and calculation method as available now through the P.S.A. and G.T.M. A method to produce systematically desirable nuclides is not part of those patent applications. The P.S.A. and G.T.M. methods have a completely different conception and approach and lead to different conclusions. The invention provides a systematic method for the transformation of nuclides through the following steps: 1.Based on the objectives of the transformation ( energy production, production of usefull stable or unstable nuclides, or elimination of hazardous nuclides) a range of desired characteristics of initial or final nuclides and of transitions can be specified.

2. By means of the P.S.A. and the G.T.M. a systematic,preliminary choice of optimal options can be made,based on the objectives and the available facilities and constraints. 3. The range of options, can be refined and limitedby subsequent calculations on the basis of the G.T.M. to single out optimal pathways for the transitions, the types ofbombarding particles to be used or the radiations, the required energies for optimizing the cross sections of the desired reactions and minimizing or eliminating the yields of undesired, accompanying transformations.

4. The transitions can be performed finally by selection,programming and implementation of the necessary equipment according to the previously, systematically gathered information and the calculated specifications. Bas ic concepts of the invention

The invention presents a comprehensive .atomic/nuclear model (the Galactic Trinity Model = G.T.M.) in relation with a Periodic System of Atoms ( = P.S.A. ),which can satisfy the above mentioned scientific and technological needs, to be used as a basic method in nuclear technology. The G.T.M. and P.S.A. provide a method for the systematic transformation by appraisal of : 11 characteristics and behaviour of all nuclides separately and in their interrelation; 2) options to transform nu elides through various pathways ;3)optimal energies,particleand radiation types to be used .

The model is based on a holistic view or the atomary structure and the three fundamental atomary building blocks :neutron, proton and electron.Mendeleev's Periodic System of Elements is based on a partial view point: the periodic addition of charged-particle pairs(proton + electron), combined in groups of isotopes into elements. Similar partial views yield by periodic addition of neutrons a Periodic System of Neutrons with groups of isotones, and by periodic addition of nuclear particles a Periodic System of Isobars. A fourth partial Periodic System of Isarythms can be defined by considering periodic addition of any atomic particle, disregarding its character. This results in groups of atoms with identical numbers of building blocks, called isarythms. The four partial periodic systems -each constructed from a different view point - form together the underlying,fundamental organisation of matter in the Periodic System of Atoms, with the neutron as primary unit and related "to the secondary units proton and electron by beta processes.

The P.S.A. can be portrayed in triangular format (Figure 1) or in lattice format (Figures 2 and 3) . The rest-mass energy relations in the lattice are given in Figure 4. The binding energy of a neutron = mass deficit between rest mass of the neutron and the sum of the restmasses of the proton and the electron, equals 0.783 MeV and is called 1 Binding unit or 1 Bu. The Bu is a convenient yardstick to express the mesh values of restmass energy in the lattice of the P.S.A. The lattice is a modified version of conventional nuclide charts, more suited to bring out the periodicities.

According to the G.T.M. a particular neutron- and proton/electron configuration can be assigned to each conceivable type of atom. These two configurations form the coordinates for the particular position of the atom in the lattice of the P.S.A. The possible combinations of neutron- and proton/electron configurations become less stable v.ith increasing distance from the beta valley stability line (Figure 21). Atoms with identical neutron configurations are situated on straight diagonal, isotonic lines and atoms with identical proton/elec tron configurations are located on straight, horizontal , isotopic lines. The Galactic Trinity Model is a comprehensive,holistic model 01 the atom to account for its composition, spatial structure and interaction with other atoms or nuclei. The atom consists -according to the G.T. M. - of:

1 ) an electron envelope, subdivided in shell- and subshell configurations according to the quantum-mechanical subdivisions of present-day atomic theory;

2) a nucleus, consisting of an intertwined, periodic alternation of neutrons and protons, arranged equally in shells and subshells. This nuclear shell model is however strongly different from the conventional shell model as developed by Mayer and Jensen(Figures 5 and 10). In the G.T.M. the proton shells and subshells of a neutral atom are identical in configuration and filling order to their electronic counterparts. The filling of the neutron shells and subshells - which have the same structure and theoretical capacity as those of the protons and electronsproceeds differently. Neutron subshells are filled up to capacity with increasing mass numbers from inner to outer subshells without leaving temporary or permanent vacancies in the subshells as observed in electron and proton subshells. All atomic particles and their configurations can be described now in the same universal spectroscopic notation of atomary physics with a prefix N (neutron), P (proton) or E (elec tron). The nuclear structure is twinned; each nucleus consist of a succession of double subshells, an inner neutron subshe interwoven with a similar outer proton subshell. The two types are shifted in energy levels, which results in a periodi alternation of neutrons and protons in successive orbits (Figures 5,6,9). In Figure 5 the nuclear structure of each element is given for the isotope with the highest relative abun dance in case of stable elements, and for the isotope with the longest half-life for unstable elements. The nuclear configuration for all other isotopes of an element can be deduced easily by filling or emptying the consecutive neutron subshel in consecutive order.The fundamental differences between the conventional model and the G.T.M. are summarized in Figure 10 The G.T.M. continues the line of thought of Bohr's Planetary Model for the spatial distribution of the atomic particles in a new way by combining the quantum-mechanical basis of the shell configurations with the Schroedinger wave equations a nd the movement of the atomic particles in orbits in planes of rotation with fixed relative positions of the latter, (Figures 8 and 9). The atomic building blocks rotate in circular or elliptic orbits in planes under fixed angles, which are specific for each shell and subshell. The degree of stability of the atom is coupled to the degree of rotational symmetry around the center of gravity of the atom, with a preference for pairing of identical particles to maintain the delicate, rotational balance of gravitational, electromagnetic and centrifugal forces. The energetic fine-tuning of the rotational configurations is made possible by rotations in space of the spin vectors of the particles. The spin vectors are directed radially outwards in the orbital planes in those cases where no residual, net angular momentum is observed. In the case of net angular momentum the spin vectors are oriented perpendicular to the orbital planes in such a fashion that an outside observer measures a counterclock-wis nuclear angular momentum for nuclei with positive parity and a clockwise angular momentum for nuclei with negative parity (Figure 7). Spin/parity balance equations can be ma de for every transformation. The configuration of the spin vectorsdetermines the magnetic properties. Spin/parity balances of nuclei showing a deficit are associated with Szilard-Chalmers processes. The successive filling of the neutron-, proton-,and electron subshells results in a spatial distribution pattern of particles comparable to the configuration of a galaxy, the basic building stone of the Universe (Figure9). The/riajority of the particles rotates in a disc and a smaller number (especially from the d ana f subshells) in a globular halo around it.Due to the presence of net angular momentum from unaligned spin vectors the atomic and nuclear discs mayshow warps in opposite directions on eithei side of a cross section, like observed for galaxies. The P.S.A. and the (S.T.M. relate the structure of maiter at the scale of the atom to the structure of matter at the scale of the Universe according to the same fundamental principles. The use of the P . S . A . and the G. T .M . in und erstanding experimental data of widely diiferent character yields a list of results which will be mentioned partly and illustrated only briefly in the framework of this application.However, it may serve to illustrate the scope of the invention.

The G.T.M. explains and makes accessible to systematic calculations the following main groups of items:

1) the deviations in periodicity of atomic mass (Figure 12), the distribution pattern of stable and unstable isotopes in the P.S.A. (Figure 21);

2) the patterns of relative abundances and half-lives and the factors governing them (Figures 13,14,15), the origin of the magic numbers (Figure 10);

3) the distribution of the various decay modes in the P.S.A. (Figures 2,21,19), the factors governing branching decay and degree of "forbiddenness" or "hindrance" of transitions (Fig.

21,20,24);

4) the variations in separation and binding energies of neutrons, protons and alpha particles and their absorption aad a ctivation cross sections (Figures 18,19,20);

5) spin/pa rity relations in nuclear interactions and in nucleus/electron-shell interactions in Szlla rd-Chalmers processes (Figures 7,23,24 and 16);

6) the processes underlying spontaneous and induced fission and alpha decay and the mass distribution of fission fragments under different bombarding energy conditions.

An example of the application of the invention to the systematic transformation procedure for hazardous nuclides is quoted by reference to the patent application no.8203982 byEngelen, filed on Oct. 15 th 1982 in the Netherlands and scheduled for publication on April 15 th ,1984. The invention is elucidated further in the listed Figures:

Figure 1. Construction of the first part of the Periodic System of Atoms in triangular format by means of isarythms. Figure 2. The first part of the P.S.A. in lattice format. Figure 3. Relation between the component partial periodic systems and their combination in the underlying P.S.A. Figure 4. Rest mass energy relations in the lattice of the P.S.A.

Figure 5. a and b.Nuclear configurations of the elements according to the G.T.M. For stable elements the most auundant isotope is given, for unstable elements the isotope with the longest half-life.

Figure 6. Examples of atomic cross sections of atoms with low mass numbers.

Figure 7. Spin/parity assignment scheme. Legend: 1.vacant position in orbit; 2. occupied position in orbit with radial orientation of spin vector in orbital plain; 3. occupied position in orbit with orientation of spin vector perpendicular to orbital plane ;4.circular or elliptic orbit; 5. residual,una ligned spin/parity. Figure 8. Selected possibilities of configurations of orbital planes for successive subshells. Figure 9. Scheme of galactic-disc type of configuration in nucleus of atoms with subshell occupation up till 2p2 , note the absence of a globular halo of particles, which starts to develop only on further filling of subshells.

Figure 10 a and b . Comparison of G.T.M. (10 a) and currentshell model according to Mayer and Jensen (10 b).The data on the conventional shell model have been derived from Valentin ( 1981 ,p.307-327), and are presented in spectroscopic. notation as used in nuclear physics. In that model a subdivision is made for the configuration according to a harmonic oscillator (columns 13,14,15) and to a Woods-Saxon potential (columns 16,17,18). The G.T.M. is portrayed in 10 a with a uniform spectroscopic notation as used in atomary physics. in the not further specified column 1 the nuclear spin/parity value can be given to indicate the orientation of the spin vectors of the nucleons with regard to their orbital plane in units of n x ½

Figure 11. Examples of nuclear cross sections of groups of isobars.

Figure 12.Example of the periodic relations between atomic rest mass and neutron configuration according to the G.T.M. Figure 13.Example of element-stability graph of iodine in relation with the subshell configuraction of its isotopes. The lower part of this type of graph contains the unstable isotopes with the natural logarithm of their half-life in seconds, the upper part the stable isotopes with their percentual relative abundance.

Figure 14. Element-stability graphs of germanium and plutonium in relation with neutron configuration. Figure 15. Element-stability graph of polonium in relation with decay modes, neutron configurations and alpha decay energies in MeV.

Figure 16. Nuclear cross sections of the isotopes of iodine. Figure 17. Nuclear cross sections of the isotopes of germanium. Figure 18.Nuclear cross sections of the isotopes of plutonium in relation with thermal neutron cross sections.

Figure 19. Nuclear cross sections of polonium in relation wit decay modes and alpha decay energies (in MeV) . Figure 20. Plot of decay energies versus mass numbers for alpha emitters from bismuth to fermium in relation to neutron configuration(bas ed on a graph by Friedlander et al.,Nuclea and Radiochemistry, 2. nd ed. Wiley,New York, 1966,p.231). Figure 21. First part of P.S.A. with all stable atoms and all atoms with dual (branched) beta decay in relation to the track of the beta valley axis. Legend: 1.beta valley axis;2. stable nuclide; 3.stable isotope with highest abundance for element; 4. unstable nuclide; 5.unstable isotope with longest half-life for element; 6. branching or dual beta decay;7. assumed dual beta decay;8. element pair with anomalous mass sequence.

Figure 22. First part of isotopes on beta stability axis of P.S.A. with nuclear cross sections and known proton emitters.

Figure 23. Examples of changes in nuclear structure due to particle exchange reactions with lead and bismuth targets. Figure 24. Examples of changes in nuclear structure due to internal transitions and beta decay of isotopes of lead, thallium and mercury.