Mark A. Williamson

Bio: Mark A. Williamson is an academic researcher from University of California. The author has contributed to research in topics: Nuclear transmutation & Enriched uranium. The author has an hindex of 1, co-authored 1 publications receiving 23 citations.

Accelerator-driven transmutation of spent fuel elements

Abstract: An apparatus and method is described for transmuting higher actinides, plutonium and selected fission products in a liquid-fuel subcritical assembly. Uranium may also be enriched, thereby providing new fuel for use in conventional nuclear power plants. An accelerator provides the additional neutrons required to perform the processes. The size of the accelerator needed to complete fuel cycle closure depends on the neutron efficiency of the supported reactors and on the neutron spectrum of the actinide transmutation apparatus. Treatment of spent fuel from light water reactors (LWRs) using uranium-based fuel will require the largest accelerator power, whereas neutron-efficient high temperature gas reactors (HTGRs) or CANDU reactors will require the smallest accelerator power, especially if thorium is introduced into the newly generated fuel according to the teachings of the present invention. Fast spectrum actinide transmutation apparatus (based on liquid-metal fuel) will take full advantage of the accelerator-produced source neutrons and provide maximum utilization of the actinide-generated fission neutrons. However, near-thermal transmutation apparatus will require lower standing inventories of plutonium and higher actinides. Uranium, presently the largest volume constituent in nuclear waste, is fully utilized and not discharged as waste. Since no plutonium, higher actinides or fission products are present in the reconstituted fuel elements, the present processes can be used repeatedly. Since the performance of the existing reactors is not changed, full utilization of both thorium and uranium resources is achieved.

Biomarker generator system

Abstract: A biomarker generator system for producing approximately one (1) unit dose of a biomarker. The biomarker generator system includes a small, low-power particle accelerator ('micro-accelerator') and a radiochemical synthesis subsystem having at least one microreactor and/ or microfluidic chip. The micro-accelerator is provided for producing approximately one (1) unit dose of a radioactive substance, such as a substance that emits positrons. The radiochemical synthesis subsystem is provided for receiving the radioactive substance, for receiving at least one reagent, and for synthesizing the approximately one (1) unit dose of a biomarker.

Neutron-driven element transmuter

Abstract: A material is exposed to a neutron flux by distributing it in a neutron-diffusing medium surrounding a neutron source. The diffusing medium is transparent to neutrons and so arranged that neutron scattering substantially enhances the neutron flux to which the material is exposed. Such enhanced neutron exposure may be used to produce useful radio-isotopes, in particular for medical applications, from the transmutation of readily-available isotopes included in the exposed material. It may also be used to efficiently transmute long-lived radioactive wastes, such as those recovered from spent nuclear fuel. The use of heavy elements, such as lead and/or bismuth, as the diffusing medium is particularly of interest, since it results in a slowly decreasing scan through the neutron energy spectrum, thereby permitting very efficient resonant neutron captures in the exposed material.

Method of producing actinium-225 and daughters

Abstract: A method of producing an isotope comprising directing electrons at a converting material coated with a coating material, the coating material having an atomic number of n, whereby interaction of the electrons with the converting material produces photons, and whereby the photons produced interact with the coating material to produce an isotope having an atomic number of n-1. In preferred embodiments, the converting material is Tungsten, the coating material having an atomic number of n is Radium-226, and the isotope having an atomic number of n-1 is Radium-225.

Sustainable Modular Transmutation Reactor

Abstract: A light water reactor to safely convert depleted uranium into a fuel source that could be used as a sustainable source of energy for centuries. The reactor is a type of breed-burn reactor uniquely combined with a proliferation-resistant fuel cycle with no uranium enrichment and no plutonium isolation. It is comprised of a compact factory-produced fast region and a thermal region that produces about 95% of the core power and contains the passageways for transports of delayed-neutron emitters to the fast region, where they can provide additional neutrons (source-based mode) or all the necessary excitation without an external neutron source (self-regulating mode). A second embodiment of the invention is a small unit driven by a neutron source with beam recycling for propulsion, electrical power or radioisotope production. It could also serve as a demonstration facility for the transmutation reactor with fission-fusion fuel.

Field analysis of geological samples using delayed neutron activation analysis

Abstract: A system and method for rapidly analyzing elemental abundances in rock or soil samples ( 14 ) under field conditions. The system uses a portable neutron source ( 12 ) to allow neutron activation analysis of elements having identifiable radioactive decay characteristics. A radiation detector ( 18 ) detects radiation released by the sample ( 14 ) and provides radiation testing results to an amplifier ( 26 ) for computing the concentration of trace elements in the sample with a high degree of accuracy.