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Description
The recently evolved U4 upgrade of the single-pass RF linac driver for IFE [1] is based on Basko’s assessments of the requirements for stable compression, fast ignition, and high-gain fusion burn of large cylindrical fuel pellets [2]. Basko’s simulations use the beams of Koshkarev’s driver [3]: 100 GeV Bi for compression and eight, telescoping Pt beams for fast ignition: four Pt isotopes in either charge state. U4’s multiple, charge-balanced beams drive both compression and fast ignition. U4’s 10 single-isotopic linacs are duplexed for + and - beams in separate bores of integrated RF structures. Large unit-cost reductions are presumed from new designs innovated to be mass manufactured to meet the large energy demands of the future.
A linac for each species led to the concept of a beam-transformer switch-network (Kvetchnet) that converts incoming parallel beams of single isotopes to multiple-isotope outgoing beams set to telescope longitudinally during ~3 km identical-length drifts to pellets in multiple chambers. Multiple chambers are an essential foundation for the U4 energy facility’s attractive economics. At the intersections between incoming lines of isotopes (10, duplexed) and the outgoing beamlines (8, duplexed) are a pair of kicker magnet switches (50 nsec rise. 500 ns flattop) connected by a d.c. beamline ~16 m long (5o intersection Kvetchnet). 160 identical transformer kits: 320 switches and 160 connector beamlines.
U4’s vitality derives from combined technical feasibility and the outlook for low-cost energy due to the large economies of scale of many chambers with one driver igniting high yield fusion pulses round-robin. Chambers are free from the neutron-damage materials problem that is MFE’s nemesis. LLNL’s exhaustive (1977-85) and highly favorable assessment of the HYLIFE (High Yield Lithium Injected Fusion Energy) chamber for IFE [4] assumed ~1 pps energy yields ≥ 1 ton TNT/MWh/BOE—substantial economic value per pulse. Neutronically thick injected lithium eliminates the neutron-materials problem while containing the blasts. HYLIFE’s advantages depend on large pulses to make lithium protection work, as does U4’s further improved chamber. U4’s combined advantages enable IFE to achieve major acceleration of fusion energy. ~ 2 BOE per second in ~10 chambers is the output of a supergiant oil field.
References
[1] Burke, R.J., The Single Pass RF Driver: Final Beam Compression, Nuclear Instruments and Methods in Physics Research Section A, Volume 733, 1 January 2014, Pages 158-167.
[2] Basko, Mikhail M., M. D. Churazov and Aleksei Aksenov. “Prospects of heavy ion fusion in cylindrical geometry.” Laser and Particle Beams 20 (2002): 411-414.; Ramis, Rafael and Jürgen Meyer-ter-Vehn. “On thermonuclear burn propagation in a pre-compressed cylindrical DT target ignited by a heavy ion beam pulse.” Laser and Particle Beams 32 (2014): 41-47.
[3] Koshkarev, D.G. Charge-symmetric driver for heavy-ion fusion. Nuov Cim A 106, 1567–1573 (1993). https://doi.org/10.1007/BF02821253; D.G. Koshkarev, A.V. Barkhudaryan, AN. Talyzin, “New concept of a charge-symmetric driver for HIF,” Nuclear Instruments and Methods in Physics Research A415 (1998) 263-267.
[4] HYLIFE: Blink, James A., Hogan, William J., Hovingh, Jack, Meier, Wayne R., and Pitts, John H. (Compilers); Kellie L. Essary, Kevin E. Lewis. (editors) "High-Yield Lithium-Injection Fusion-Energy (HYLIFE) reactor". 1985. United States. Manuscript date: December 23, 1985. UCRL—53559. https://www.osti.gov/biblio/6124368
