Development of experimental and computational frameworks to predict subcooled flow boiling in the LANL Isotope Production Facility

Journal Article · Tue Jan 10 00:00:00 EST 2023 · International Journal of Heat and Mass Transfer

DOI:https://doi.org/10.1016/j.ijheatmasstransfer.2022.123836· OSTI ID:1909562

Seong, Jee Hyun ^[1]; Morrell, Jonathan Troy ^[1]; Singh, Bhavini ^[1]; Woloshun, Keith Albert ^[1]; Olivas, Eric Richard ^[1]; Lance, Patrick K. ^[1]; Kollarik, Nate ^[1]; O'Brien, Ellen Margaret ^[1]; Vermeulen, Christiaan ^[1]

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1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

Cooling is crucial to maintain the integrity of target systems in isotope production facilities. At Los Alamos National Laboratory (LANL)’s Isotope Production Facility (IPF), multiple encapsulated targets are stacked and irradiated in tandem with a 100 MeV, ~250μA proton beam. To facilitate effective heat removal, these stacked targets are separated and cooled via a series of water channels. At these beam currents, this high-energy proton beam heats the target system, likely initiating subcooled flow boiling in the cooling channels. However, in-beam monitoring of the IPF target system is not possible due to the extreme radiation environment, and the necessarily significant shielding. To better understand high-power target performance, we developed ex-situ experimental and computational frameworks to predict the behavior of subcooled flow boiling at IPF. Subcooled flow boiling experiments on Inconel 625 samples under IPF conditions (2 bar pressure, 10 GPM flow rate (i.e., 2249 kg/m²/s), 85 K subcooling) revealed that IPF's average operating power is at the early stage of boiling with a heat transfer coefficient of 48,000 W/m²/s. The proposed modeling framework enables us to predict a complete boiling curve, i.e., single-phase heat transfer, onset of nucleate boiling, two-phase heat transfer, and critical heat flux (CHF), with specification of input boiling parameters up to intermediate heat flux levels. The estimated CHF under IPF conditions is 5.2 MW/m². Experimental data under reduced conditions (2 bar pressure, 1.5 GPM flow rate (i.e., 337 kg/m²/s), 45 K subcooling) served as validation cases for the computational modeling. This computational model can be further extended to more complicated systems replicating the real IPF configuration, for instance, to study void distribution as a function of the incident proton beam profile and coolant velocity profile of multiple cooling channels. Finally, the proposed experimental and computational frameworks provide a means to better understand cooling systems in the isotope production facilities at different accelerators, where in-beam monitoring of the cooling process is not available.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA); USDOE Office of Science (SC), Engineering & Technology. Office of Isotope R&D and Production
• Grant/Contract Number: 89233218CNA000001
• OSTI ID: 1909562
• Report Number(s): LA-UR-22-30515
• Journal Information: International Journal of Heat and Mass Transfer, Journal Name: International Journal of Heat and Mass Transfer Vol. 203; ISSN 0017-9310
• Publisher: Elsevier
• Country of Publication: United States
• Language: English

Related Subjects

07 ISOTOPE AND RADIATION SOURCES
computational modeling
isotope production
subcooled flow boiling