Development of an accelerator-based neutron source to prototype Mo-99 production, part I: A liquid LBE windowless target

Journal Article · Wed Nov 15 00:00:00 EST 2023 · Nuclear Engineering and Design

DOI:https://doi.org/10.1016/j.nucengdes.2023.112735· OSTI ID:2532369

Kong, Ran ^[1]; Wahlen, Robert ^[2]; Grimm, Terry ^[2]; Grote, Matthew ^[2]; Singh, Bhavini ^[3]; Olivas, Eric Richard ^[3]; Woloshun, Keith Albert ^[3]

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1. Niowave, Inc., Lansing, MI (United States); Purdue University, West Lafayette, IN (United States)
2. Purdue University, West Lafayette, IN (United States)
3. Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)

In this article, Molybdenum-99 (Mo-99)’s decay product, technetium-99 (Tc-99 m), is one of the most critical isotopes for medical diagnostics. To provide U.S. domestic supply of Mo-99 without using high-enriched uranium (HEU), a subcritical uranium target assembly (UTA) is irradiated by an accelerator-based neutron source to create Mo-99 through fission. This study discusses the development of the accelerator-based neutron source. The high-energy electrons from the accelerator irradiate a liquid lead-bismuth eutectic (LBE) target to produce neutrons. Part I of this work focuses on numerical and experimental analysis towards the development of a liquid LBE windowless target. Unlike the existing windowless targets in literature, the current design creates a vertical free surface for a beam to irradiate. First, a hydrodynamic analysis of the LBE windowless target is performed. Simplified analytical calculations are assisted by 2D computational fluid dynamics (CFD) simulations to design the target, with the focus on eliminating recirculation zones and avoiding cavitation. With the optimized geometry, the experimental study is performed to investigate the flow hydrodynamics using liquid LBE. The experiments (1) compare pressure drop in the system to correlation predictions; (2) visualize the free surface liquid LBE flow from the beam view; (3) validate the LBE flow profile using temperature sensitive paint from the side view; and (4) validate the liquid LBE film thickness using gamma densitometer measurements. Second, the power handling capability of the designed windowless target is investigated. The divider plate in the current design is susceptible to overheating due to the thin LBE film in front. As LBE erosion and corrosion is likely to occur at an LBE velocity of 2.0 m/s and temperature above 500 °C, a power limit of 10 kW of beam power was established to prevent this corrosion from occurring, which is calculated by a Nusselt number correlation. The divider plate surface temperature at 10 kW agrees well with the 3D CFD simulation results. Part I demonstrates the fundamental physics in liquid LBE windowless target design and associated testing. A companion paper, Part II will demonstrate how to couple this windowless target into the Mo-99 production system, including an accelerator system operating under an ultra-high vacuum and the UTA cooled by water at room temperature.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA); USDOE National Nuclear Security Administration (NNSA), Office of Defense Nuclear Nonproliferation; USDOE National Nuclear Security Administration (NNSA), Office of Defense Programs (DP)
• Grant/Contract Number: 89233218CNA000001
• OSTI ID: 2532369
• Alternate ID(s): OSTI ID: 2369117
• Report Number(s): LA-UR--23-24836
• Journal Information: Nuclear Engineering and Design, Journal Name: Nuclear Engineering and Design Vol. 415; ISSN 0029-5493
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
Accelerator Design, Technology, and Operations
Accelerator driven system
LBE windowless target
Mo-99
Neutron source