Parametric Study of 99Mo Production Using a Sub-critical Low Enriched Uranium Assembly Design Proposed by Niowave Inc.

The radioisotope, technetium-99m (t1/2=6 hours) is used in over 80% of diagnostic medical imaging and is the daughter product from the radioactive decay of the isotope, molybdenum-99 (t1/2=66 hours). 99Mo is a fission product, with a fission yield of 6.1%, and therefore can be produced by nuclear reactors. While 99Mo has been produced using highly enriched uranium (HEU), there is an international interest to produce this isotope using low enriched uranium (LEU) due to the nuclear proliferation concerns of HEU. Niowave Inc. is a facility that has plans to produce 99Mo in the United States. The production of 99Mo in the US ensures its seamless availability to benefit the people who need 99mTc based medical diagnostics in the country. 99Mo production was studied for an electron beam and sub-critical LEU assembly design proposed by Niowave Inc. by applying Monte Carlo radiation transport and coupled isotope generation-depletion calculations. In addition, the production of 135Xe, 135I 131I, 239Pu, 105Ru and 105Rh were also investigated. The Niowave design was studied by varying neutron moderators in the sub-critical system and LEU enrichment to predict optimal production of 99Mo and other radioisotopes products of interest. The neutron moderators that were considered for this study are light water, heavy water and beryllium. 99Mo production rate was studied, the predicted value for this study is ~9 kCi per week with a 235U enrichment of 10% and light water as the neutron moderator. This amount of 99Mo production could meet 12% of the US demand from one production facility. Studies found that water is the best neutron moderator for the current design to maximize the production of 99Mo. The light-water-moderated system achieves highest criticality level as well as a highest thermal neutron flux and power, when compared to the other two candidates. Heavy water is a better neutron moderator than beryllium for the current design, however, it is not as good as water. Even at 19.9% enriched fuel, heavy water and beryllium do not achieve the neutron flux, power or 99Mo production levels when water is used moderator in the system. In conclusion, the studies conducted found that water is the best moderator candidate for this design, maximizing the production of 99M

Parametric Study of 99Mo Production Using a Sub-critical Low Enriched Uranium Assembly Design Proposed by Niowave Inc.

The radioisotope, technetium-99m (t1/2=6 hours) is used in over 80% of diagnostic medical imaging and is the daughter product from the radioactive decay of the isotope, molybdenum-99 (t1/2=66 hours). 99Mo is a fission product, with a fission yield of 6.1%, and therefore can be produced by nuclear reactors. While 99Mo has been produced using highly enriched uranium (HEU), there is an international interest to produce this isotope using low enriched uranium (LEU) due to the nuclear proliferation concerns of HEU. Niowave Inc. is a facility that has plans to produce 99Mo in the United States. The production of 99Mo in the US ensures its seamless availability to benefit the people who need 99mTc based medical diagnostics in the country. 99Mo production was studied for an electron beam and sub-critical LEU assembly design proposed by Niowave Inc. by applying Monte Carlo radiation transport and coupled isotope generation-depletion calculations. In addition, the production of 135Xe, 135I 131I, 239Pu, 105Ru and 105Rh were also investigated. The Niowave design was studied by varying neutron moderators in the sub-critical system and LEU enrichment to predict optimal production of 99Mo and other radioisotopes products of interest. The neutron moderators that were considered for this study are light water, heavy water and beryllium. 99Mo production rate was studied, the predicted value for this study is ~9 kCi per week with a 235U enrichment of 10% and light water as the neutron moderator. This amount of 99Mo production could meet 12% of the US demand from one production facility. Studies found that water is the best neutron moderator for the current design to maximize the production of 99Mo. The light-water-moderated system achieves highest criticality level as well as a highest thermal neutron flux and power, when compared to the other two candidates. Heavy water is a better neutron moderator than beryllium for the current design, however, it is not as good as water. Even at 19.9% enriched fuel, heavy water and beryllium do not achieve the neutron flux, power or 99Mo production levels when water is used moderator in the system. In conclusion, the studies conducted found that water is the best moderator candidate for this design, maximizing the production of 99M

Improved high temperature solar absorbers for use in Concentrating Solar Power central receiver applications.

Concentrating solar power (CSP) systems use solar absorbers to convert the heat from sunlight to electric power. Increased operating temperatures are necessary to lower the cost of solar-generated electricity by improving efficiencies and reducing thermal energy storage costs. Durable new materials are needed to cope with operating temperatures >600 C. The current coating technology (Pyromark High Temperature paint) has a solar absorptance in excess of 0.95 but a thermal emittance greater than 0.8, which results in large thermal losses at high temperatures. In addition, because solar receivers operate in air, these coatings have long term stability issues that add to the operating costs of CSP facilities. Ideal absorbers must have high solar absorptance (>0.95) and low thermal emittance (<0.05) in the IR region, be stable in air, and be low-cost and readily manufacturable. We propose to utilize solution-based synthesis techniques to prepare intrinsic absorbers for use in central receiver applications