DOE OSTI · 3391613
Experimental observation and integrated modelling of proton-beryllium fusion in He and D plasmas at JET
Abstract
Validated integrated modelling of JET ITER-like wall experiments in which fusion performance is driven by reactions between fast ions and intrinsically present metal wall impurities is presented. A steady-state L-mode plasma with dominant proton-beryllium fusion and neutron yields of up to ≈ 6·10 13 s -1 is developed in He and D, via radiofrequency heating of a H minority. The fusion drive is unambiguously confirmed by the neutral particle analyser, fast ion loss detector, and γ-ray diagnostics. Experiments are analysed via an integrated modelling framework, developed to model the two-stage proton beryllium-fusion chain and produce high-fidelity fusion product source terms. The modelling chain comprises TRANSP and JETTO for plasma core modelling, LOCUST for full orbit product tracking and collisional slowing-down, DRESS to resolve two- and three-body fusion kinematics, and MCNP for neutron transport calculations. Modelling shows that the primary 9 Be(p,n) 9 B reaction is the dominant neutron emitter at naturally present concentrations of beryllium in these experiments. The yield contribution of secondary reactions between fusion products and beryllium, 9 Be(d,n) 10 B and 9 Be(α,n) 12 C, is found to be negligible. The proton-deuteron knock-on effect in D plasmas is modelled, which is calculated to contribute ≈ 25% to the total neutron yield. For both He and D discharges the total computed neutron rates match fission chamber (FC) measurements within the combined experimental and computational uncertainty, with an average discrepancy of ≈ ± 20%. Realistic proton-beryllium neutron sources are propagated through JET’s MCNP neutron transport model which shows that 235 U FCs’ response is sensitive to p–Be source changes, with up to ≈ 10% variation compared to a D–D neutron source. We show that the high-energy tail of the fast proton minority can be studied with multi-foil neutron activation. The framework is also applied to the study of interactions between fast protons and boron impurities, of relevance to ITER. We calculate that in JET conditions a significant alpha source with DT-like energies could be generated through 11 B(p, α)2α fusion, and detected via γ-emission in secondary interactions between fast alphas and boron. The work represents an important step towards validating predictive integrated modelling capabilities for non-standard fusion reactions.
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Štancar, Žiga [United Kingdom Atomic Energy Authority (UKAEA), Abingdon (United Kingdom)], Eriksson, J. [Uppsala University (Sweden)], Oliver, H.J.C. [United Kingdom Atomic Energy Authority (UKAEA), Abingdon (United Kingdom)], Kiptily, V.G. [United Kingdom Atomic Energy Authority (UKAEA), Abingdon (United Kingdom)], Conroy, S. [Uppsala University (Sweden)], Čufar, A. [Jozef Stefan Institute (IJS), Ljubljana (Slovenia)], Hjalmarsson, A. [Uppsala University (Sweden)], Kazakov, Ye.O. [Ecole Royale Militaire, Brussels (Belgium)], Ghani, Z. [United Kingdom Atomic Energy Authority (UKAEA), Abingdon (United Kingdom)], Gorelenkova, M. [Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)] (ORCID:0000000184871396), Boboc, A. [United Kingdom Atomic Energy Authority (UKAEA), Abingdon (United Kingdom)], Carvalho, P. [United Kingdom Atomic Energy Authority (UKAEA), Abingdon (United Kingdom)], Chomiczewska, A. [Institute of Plasma Physics and Laser Microfusion (IPPLM) Warsaw (Poland)], Delabie, E. [Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)], Dreval, M. [Kharkiv Institute of Physics and Technology (KIPT) (Ukraine)], Garzotti, L. [United Kingdom Atomic Energy Authority (UKAEA), Abingdon (United Kingdom)], Kirov, K. K. [United Kingdom Atomic Energy Authority (UKAEA), Abingdon (United Kingdom)], Kos, D. [United Kingdom Atomic Energy Authority (UKAEA), Abingdon (United Kingdom)], Lawson, K. D. [United Kingdom Atomic Energy Authority (UKAEA), Abingdon (United Kingdom)], Lengar, I. [Jozef Stefan Institute (IJS), Ljubljana (Slovenia)], Lennholm, M. [United Kingdom Atomic Energy Authority (UKAEA), Abingdon (United Kingdom)], Lerche, E. [Ecole Royale Militaire, Brussels (Belgium)], Litaudon, X. [Alternative Energies and Atomic Energy Commission (CEA), Cadarache (France)], Litherland-Smith, E. [United Kingdom Atomic Energy Authority (UKAEA), Abingdon (United Kingdom)], Maslov, M. [United Kingdom Atomic Energy Authority (UKAEA), Abingdon (United Kingdom)], Menmuir, S. [United Kingdom Atomic Energy Authority (UKAEA), Abingdon (United Kingdom)], O’Mullane, M. [United Kingdom Atomic Energy Authority (UKAEA), Abingdon (United Kingdom)], Parr, E. [United Kingdom Atomic Energy Authority (UKAEA), Abingdon (United Kingdom)], Patel, A. [United Kingdom Atomic Energy Authority (UKAEA), Abingdon (United Kingdom)], Snoj, L. [Jozef Stefan Institute (IJS), Ljubljana (Slovenia)], Sydenham, R. [University of Portsmouth (United Kingdom)], Sun, H. J. [United Kingdom Atomic Energy Authority (UKAEA), Abingdon (United Kingdom)], Villari, R. [ENEA Frascati Research Center (Italy)], Wang, V. T. [Queen Mary University of London (United Kingdom)], Zotta, V. K. [Sapienza University of Rome (Italy)]. 2026-07-21. Experimental observation and integrated modelling of proton-beryllium fusion in He and D plasmas at JET. https://doi.org/10.1088/1741-4326/ae870b
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