INNOVATION LEADS THE WAY TO ATTRACTIVE INERTIAL FUSION ENERGY REACTORS - PROMETHEUS-L AND PROMETHEUS-H

Two conceptual inertial fusion energy (IFE) reactor design studies emp loying innovative system concepts have been completed for the US Depar tment of Energy. These concepts enable power plants with inertially co nfined plasmas to be economically competitive with other energy source s and provide safety and environmental advantages. A KrF driver employ s 960 electric discharge laser amplifiers to enhance driver reliabilit y and target illumination with a loss of one or more amplifiers. A non -linear laser architecture uses Raman accumulator cells to combine and enhance the beam quality and stimulated Brillouin scattering cells fo r beam compression. Optical delay switchyards maximize the utilization of beam energy to provide proper beam pulse forms to the target. Graz ing incidence metal mirrors are the final optical elements that employ a high rigidity SiC support structure and graded thickness aluminum r eflective surface material to obtain a life-of-plant optical element w ith a direct line-of-sight to the target within 20 m of the target. Si xty of these laser beamlines symmetrically illuminate the direct-drive target. A performance and economic systems code determined the optimu m laser beam energy as 4 MJ corresponding to a target gain of 124. Whe n pulsed at 5.65 Hz, the fusion power is 2807 MW. To reduce the cost o f traditional, lengthy, multiple-beam heavy ion drivers, a single-beam LINAC driver with storage rings was adopted. A charge state of two wa s used to shorten the length and cost of the driver. An ion energy of 4 GeV reduced the number of beams. The LINAC is rapidly pulsed 18 time s. Pulses are contained in storage rings and combined to form 2 prepul se and 12 main beams. These are subdivided to illuminate the indirectl y driven target from two sides. Triplet coil sets ballistically focus the beams on the outside of the blanket. Channel transport is proposed to deliver the beams in two 6 mm diameter channels to the target. A t otal beam energy of 7 MJ is delivered to the target to obtain a gain o f 103 and fusion power of 1818 MW at 3.54 Hz. A common reactor design is used for the laser and heavy ion beam systems. Low activation SiC m aterial is used for the first wall and blanket systems. The first wall is protected with a thin film of liquid lead that is evaporated by ea ch microexplosion and recondensed between explosions, thus providing p rotection and vacuum pumping of target debris. A lithium oxide breeder is cooled with low pressure, high temperature helium that minimizes s tored energy and improves system safety and activation. The plant Leve l of Safety Assurance is one, and waste disposal is class C or better. Double-walled steam generators maintain low tritium permeation to the environment. High-temperature helium and first wall lead coolants are used with a 42% efficient, advanced Rankine cycle to deliver a power output of 1000 MW for both plant designs. All systems were optimized t o deliver the lowest cost of electricity.