A Fast Neutron Source for Material Irradiation using a Superconducting Electron Linac

Next generation reactor R&D aims to produce safer, longer lasting and economically viable nuclear power plants. New designs rely on novel materials that are resistant to both corrosive environments and radiation damage. Testing these novel materials requires an intense fast neutron environment, commonly created with a nuclear reactor or a national laboratory scale accelerator such as the proposed Material Test Station at Los Alamos National Lab (using a 800 MeV proton beam). However, the need for a high fast neutron flux to induce significant material damage used to be provided by the Fast Flux Test Facility (FFTF). Unfortunately, FFTF no longer exists; and there are currently no fast-neutron reactors in the United States, and development of MTS is currently on hold. Fast neutron fluxes greater than 1014 n/cm2s is required for in-situ radiation damage studies, whereas, fluxes greater than 1015 n/cm2s is required for radiation damage studies with significant displacements per atom (DPA). We propose a convenient and low-cost alternative: an intense source of fast, fission- like spectrum, neutrons produced from a superconducting electron linac. The proposed source uses photonuclear reactions (γ,n), photo-fission reactions (γ,f), and neutron-induced fission (n,f), producing fast neutron fluxes greater than 1014 n/cm2s. The electron linac specification for the proposed fluxes requires a 40 MeV electron beam with beam powers over 50 kW. This accelerator energy and power level is within the capabilities of superconducting linacs under development at Niowave. In addition to demonstrating fast fluxes in excess of 1014 n/cm2s, we will explore methods and layout plans for exceeding fast fluxes 1015 n/cm2s. Independent of this proposal, Niowave is building a radioisotope production facility using a 40 MeV and >100 kW superconducting electron linac. The proposed fast neutron source will utilize the same linac as the isotope production station. However, a beamline switchyard will direct the beam between the two end-stations: one for isotope production, another is for material irradiations. Because a majority of the development is already underway with the isotope production facility, and because of the progress we made in Phases I and II, our intent is to have the proposed commercial fast neutron source operational by the completion of Phase IIA. In addition to offering beam time at our user facility we intend to build a dedicated material testing system that will be commercially available for research.