With the advent of nuclear power plants for the generation of electricity, the problem of what to do with the long-lived, high-level radioactive waste (HLRW) byproducts of the fission reactor process has been a major concern. Currently, the only option for handling these hazardous materials is long-term storage in waste disposal sites. However, since the radiotoxic byproducts (exposed fuel rods) remain lethal for thousands of years, and containment methods have proved insufficient to prevent deterioration and leakage, this has been shown to be a highly unpopular and unsatisfactory answer to the problem. Fortunately, there is a much better solution called transmutation on the horizon.
Nuclear waste transmutation is a process in which long-lived radioactive elements in spent fuel rods are converted to shorter-lived, less radiotoxic particles that produce radiation for a far shorter time span. This method can be applied to transform the long-term radioactivity, radiotoxicity, and heat from elements such as Plutonium (Pu), Minor Actinides, MA (Np, Am, Cm) and long-lived fission fragments (LLFF) such as 99Tc, 129I, 135Cs, 126Sn etc. into stable and/or short-lived materials that are either neutralized or safely stored for the duration of their decay (< 30 years).
The main radiotoxic components in spent fuel are the transuranic elements (TRU) called Pu and MA. When transmutation is induced by the irradiation of TRU using high neutron fluxes from a mono-energetic fast neutron source, these elements are transformed to short-lived, more easily contained products.
Over the last three decades, while working at the University of California, Irvine (UCI), and as a Tustin, California based corporate entity for the past eight years, the scientists at Magneto-Inertial Fusion Technologies Inc. (MIFTI) invented and developed a patented technology called Staged Z-pinch (SZP). With the use of recently developed linear transformer driver (LTD) technology, SZP methodology can be applied as a reliable source of high flux fast neutrons (2.45 MeV). MIFTI is currently conducting research based on available machines at the University of Nevada, Reno National Terawatt Facility (UNR/NTF), the University of California, San Diego (UCSD), and Cornell University, New York. All three devices have the capability to deliver a current of less than 1MA and, as a result, can produce a neutron yield of 1.0x1010 per shot.
MIFTI’s goal is to operate a pulsed power machine at a high repetition rate to optimize the neutron yield at levels predicted through simulation. Based on our studies, a machine designed for 2 to 5 MA capability will produce up to 1012 or more neutrons per shot, with a repetition rate of 1Hz. This configuration will have many applications, including transmutation that can reduce the radiotoxicity of both the currently stored high-level radioactive waste (HLRW) and any future radiotoxic products that occur through fission-based nuclear power generation.
MIFTI’s research is currently funded through a research grant from the Department of Energy Advanced Research Projects Agency (DOE/ARPA-E) and private investment. In order to design a suitable machine to produce a high rep-rate and high flux neutrons for the purpose of transmutation of HLRW, MIFTI must conduct a comprehensive feasibility study. Based on the results of that study, which will include theoretical, computational and experimental components, a compact machine of 2 to 5 MA will be designed, engineered, and built. The timeline and funds required for this study are approximately six months and $500K.