UWFDM-1019 Mechanical Design Aspects of the LIBRA-SP Light Ion Beam Driven ICF Power Reactor

LIBRA-SP is a 1000 MWe light ion beam driven inertial confinement fusion power reactor design study which utilizes a self-pinched mode for propagating ions to the target. It is driven by 7.2 MJ of 30 MeV Li ions of which 1.2 MJ is in prepulse and 6 MJ in the main pulse. There are 24 ion beams in a three tier geometry of 8 beams each. The chamber is an upright cylinder with a LiPb pool in the bottom and a flared extended roof. The blanket zone consists of solid ferritic steel tubes at a 50% packing fraction containing LiPb breeding material. The LiPb empties into the bottom pool and then flows through heat exchangers in the base of the reactor. The two front rows of tubes are called PERIT units (PErforated RIgid Tubes) and are at a distance of 4 m from the target. The front row has nozzles on its sides which spray vertical fans of liquid completely shadowing the tubes with a thin layer of liquid lithium lead and protecting them from x-rays and target debris. The deposition of the x-rays and debris ions in the liquid layer causes an explosive expansion which blows a small amount of vapor into the middle of the chamber, drives a shock through the liquid spray, and accelerates the bulk of the spray toward the PERITS. A computer code BUCKY is used to study these phenomena. The PERIT units, which are divided into upper and lower halves, each 5.3 m long, receive a 71 Pa-s impulse at 3.9 Hz reprate, have a maximum displacement of 0.8 cm and reach a maximum bending stress of 13 MPa. Beam tubes which guide the beams in the self-pinched mode are curved to avoid neutron streaming to the diodes and to avoid making contact with the PERIT units. A method for supporting these beam tubes and remotely aligning them on target will be discussed.