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 fusi on power reactor design study which utilizes a self-pinched mode for p ropagating ions to the target. It is driven by 7.2 MJ of 30 MeV Li ion s 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 exten ded roof. The blanket zone consists of solid ferritic steel tubes at a 50% packing fraction containing LiPb breeding material. The LiPb empt ies 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 uni ts (PErforated RIgid Tubes) and are at a distance of 4 m from the targ et. The front row has nozzles on its sides which spray vertical fans o f liquid completely shadowing the tubes with a thin layer of liquid li thium lead and protecting them from x-rays and target debris. The depo sition of the x-rays and debris ions in the liquid layer causes an exp losive expansion which blows a small amount of vapor into the middle o f the chamber, drives a shock through the liquid spray, and accelerate s the bulk of the spray toward the PERITS. A computer code BUCKY1 is u sed 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 rep-rate, have a maximum displacement of 0.8 cm and reach a max imum bending stress of 13 MPa. Beam tubes which guide the beams in til e self-pinched mode are curved to avoid neutron streaming to the diode s and to avoid making contact with the PERIT units. A method for suppo rting these beam tubes and remotely aligning them on target will be di scussed.