Compound isotope target assembly for production of medical and commercial isotopes by means of spectrum shaping alloys

Abstract

A neutron generator and method of using the same to produce commercial and medical isotopes. Isotopes are transmuted using fission spectrum neutrons produced in neutron multiplier alloys proximate a target isotope. The produced neutron fission spectrum is tailored or shaped by alloys disposed between the multiplier alloys and the target isotope. The tailoring alloys selectively convert the neutron fission spectrum to a nearly coherent distribution of selected high energy, fast, epithermal, or thermal neutrons. The tailoring alloys are engineered to slow the fission spectrum neutrons to the resonance energies of the selected target isotopes through scattering or hydriding of selected components of high temperature aluminum alloys that optimize neutron capture in engineered target alloys.

Description

BACKGROUND OF THE INVENTION[0001]1. Technical Field[0002]The present invention relates generally to means for producing commercial and medical isotopes, and more particularly to a method and apparatus for transmuting isotopes using fission spectrum neutrons produced in novel neutron multiplier alloys adjacent to the target precursor isotope, shaping or tailoring the produced neutron fission spectrum using novel alloys located between the multiplier and the target so as to selectively convert the neutron fission spectrum to a nearly coherent distribution of selected high energy, fast or epithermal or thermal neutrons and to slow down the fission spectrum neutrons to the resonance energies of the selected target isotopes.[0003]2. Background Art[0004]It is well known that neutrons produce valuable isotopes for use in scientific research, manufacturing and medicine. Radioactive isotopes are employed in scientific research in fields as different as hydrology and life sciences. Isotopes a...

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Benefits of technology

[0018]The neutron multiplier uses thermal neutrons to fission uranium-233, uranium-235, plutonium-239, or a selected combination thereof with americium and curium if needed. The selected fissile material is dispersed in an inert metal matrix alloy that in some preferred embodiments also contains lead or beryllium to increase the local population of neutrons. The fissile material is in ceramic or metallic form. The neutron multiplier alloy consists of aluminum and zirconium and, if needed, refractory metals such as tantalum or depleted molybdenum or tungsten, as well as engineered quantities of beryllium and/or lead, bismuth, thorium or uranium. Thermal spectrum neutrons cause the fissile material to fission at a controlled rate. The fissile material is located in its highest concentration around the central axis of the power rod in the center and the exterior side of the power tube surrounding the array. For embodiments used out side of the reactor, an electron beam of 10 milliamps with electrons accelerated to 16 to 28 MeV interact with the electron target material in the neutron multiplier, or “converter.” The electron target material in the converter is preferably an optimized alloy of tantalum, tungsten and/or rhenium to produce penetrating and energetic gamma photons. These photons interact with high-z nuclei to eject and produce neutrons. These neutrons are moderated by spectrum shaping alloys to produce thermal neutrons. The thermal neutrons thus become available to the fissile material present, in optimized quantities. Produced neutrons and or fission spectrum neutrons pass through the second alloy, namely, the spectrum shaper

Problems solved by technology

These reactions generally do not yield the quantity of desired product material as efficiently as reactions involving successive or singular neutron capture in the nuclear reactor.

Additionally, these reactions are not as efficient in the treatment of fission products to transmute them to shorter lived isotopes or common stable isotopes.

Fission reactors in the United States and Canada are generally used for and available for irradiation of target materials for medical isotope production operate primarily in the thermal neutron spectrum, limiting the isoto

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