Seminar Series - Taek K. Kim, Principal Nuclear Engineer & Dept. Manager, Nuclear Systems Analysis, Argonne National Laboratory

Nanofluid-based Accelerator-driven Transmutation Recycler (NATURE)

Abstract:

NATURE is a nanofluid-based accelerator-driven transmutation recycler for transmuting the entire U.S. minor actinides (MAs) stockpile and selected long-lived fission products within 30 years using a few proposed systems. NATURE consists of a high-energy, high-current proton accelerator; a 3,000 MWt subcritical fission blanket containing liquid lead and nano-sized suspended particles of MA and fissile mixture, termed a nanofluid; and an online cleaning system using centrifugal force to separate fission products (FP) from the nanofluid. The fission blanket uses the liquid lead-based nanofluid as a carrier for the transmutation targets and a coolant for heat transfer. To simplify spallation-target design and improve material resilience against frequent beam trips and temperature variations, NATURE adopts liquid lead. The transmutation targets, composed of MA and fissile material recovered from spent nuclear fuels, are irradiated as nano-sized particles, aiming for homogeneous suspension in the liquid lead and ejection of FPs into the lead coolant because the FP recoil distance is larger than the nanoparticle size. The FPs ejected into the lead coolant are removed from the fission blanket during operation, while nanoparticles are recycled back into the fission blanket. For this purpose, NATURE adopts an innovative online FP cleaning technology. Using the flowing capability of lead-based nanofluid and the differences in density and chemical activity between lead and FPs, FPs can be separated in a purely non-proliferation manner. A fractional lead-based nanofluid flows continuously into the cleaning system, where FPs are separated using a centrifugal force-based system such as a centrifugal contactor. The separated FPs are discharged, and the nanofluid returns to the fission blanket with an external feed of nanoparticles as needed. The fission blanket and the cleaning system are designed to be subcritical to avoid criticality issues in all operating and cleaning conditions. The proton beam from the external accelerator is directed to the spallation target installed in the fission blanket. Using spallation neutrons, the fission blanket sustains MA depletion until the desired goal is achieved. NATURE aims for net-zero cost to transmute the entire MA stockpile, which can be achieved by simplifying the transmutation system, adopting innovative FP cleaning technologies, and offsetting capital and O&M costs by selling electricity. The transmutation (depletion) rate of MA depends on various design parameters, including neutron multiplication, nanoparticle forms, the volume fraction of nanoparticles in liquid lead, the nanofluid online cleaning flow rate, the FP separation rate in the cleaning system, heat-transfer configurations, etc. For the current fission blanket design with an internal heat exchanger and an FP cleaning rate of at least 50%, NATURE can deplete about 650 kg of MA per year. The NATURE project, including design and experiments, is funded by the Advanced Research Projects Agency-Energy (ARPA-E).

Bio:

Dr. Taek K. (TK) Kim is a senior nuclear engineer and the manager of the Nuclear Systems Analysis Department, Nuclear Science and Engineering Division at Argonne National Laboratory. Also, he serves as the National Technical Director (NTD) of the Systems Analysis and Integration (SA&I) Campaign, a multinational laboratory R&D program under the US DOE Nuclear Energy (NE) Office. He served as the Dean of the Modeling, Experimentation, and Validation (MeV) Summer School in 2018. Dr. Kim joined Argonne National Laboratory in 2001. Before joining Argonne, he was a visiting scholar at Purdue University from 2000 to 2001 and worked at the Korea Atomic Energy Research Institute (KAERI) for 5 years. At Argonne, he is responsible for technical leadership and programmatic guidance across reactor physics, modeling and simulation of advanced reactors, advanced reactor concept development, and nuclear fuel cycle analyses. As the NTD of the SA&I campaign, he leads the multinational labs’ R&D programs for advanced nuclear fuel-cycle simulations and nuclear-economy assessments. He has participated in various international projects related to the design and analysis of advanced fast reactors through bilateral collaborations with the U.S., Japan, France, and Korea, as well as with international organizations such as the OECD Nuclear Energy Agency (NEA) and the International Atomic Energy Agency (IAEA).