Modular Radiation Shielding for Transportation and Use of Microreactors

Nuclear microreactors producing < 20 MW of power are being researched for portable and on-site energy production in situations such as disaster relief, mobile encampments, or remote locations where access to the regional power grid is limited or difficult. In order to facilitate mass production of nuclear reactors, reliable, replaceable, and lightweight radiation shielding must be produced for both transportation and improved maintenance procedures. Modular composite shielding is ideal for this situation, allowing for simple mass-production and assembly. The need for simplified shielding can be solved by creating a novel lightweight composite material to be used as a radiation absorber for all relevant radiation types. Proposed aluminum-based metal matrix composites contain tungsten and boron-carbide reinforcement for both gamma and neutron absorbing capabilities respectfully. In Phase I, metal matrix composite shielding consisting of an aluminum matrix reinforced with both tungsten and boron carbide was developed. Manufacturing processes were established, and the resulting composites were shown to be effective at both neutron and gamma radiation shielding. Neutron shielding performance was similar to other aluminum-boron carbide composites on the market, while gamma shielding results far surpassed typically used materials while reducing mass by over 50%. In Phase II, composite compositions will be further optimized to maximize shielding performance while driving down mass. Manufacturing processes will be scaled to fabricate demonstrator components as large as 48ö x 36ö in area. Continued radiation, mechanical, and thermal testing will be performed to generate material property databases. Developing light weight composite microreactor shielding materials will enable the proliferation of reliable, low-cost nuclear energy production. The modular composites will be cheaper to produce than custom designs, and easier to replace if damaged or during regular maintenance. Furthermore, the production process will lend itself to rapid development of additional composites using novel radiation absorbers. Additional commercial potential includes replacing commonly used shielding in both the space and medical radiation shielding markets.