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A split-core heat pipe reactor, fueled with either U(233)C or U(235)C in a tungsten cermet and cooled by 7-Li-W heat pipes, was examined for the effects of the heat pipes on reactor while trying to safely absorb large reactivity inputs through inherent shutdown mechanisms. Limits on ramp reactivity inputs due to fuel melting temperature and heat pipe wall heat flux were mapped for the reactor in both startup and at-power operating modes.
A split-core heat-pipe reactor fueled with either 233-UC or 235-UC in a tungsten cermet and cooled by 7-Li-W heat pipes is examined for the effects of the heat pipes on this reactor in trying to safely absorb large reactivity inputs through inherent shutdown mechanisms. Limits on ramp reactivity inputs due to fuel-melting temperature and heat-pipe wall heat flux are mapped for the reactor in both startup and at-power operating modes.
Description of the concept of splitting a heat-pipe reactor for out-of-core thermionics into two identical halves and using the resulting center gap for reactivity control. Short Li-W reactor heat pipes penetrate the axial reflectors and form a heat exchanger with long heat pipes which wind through the shield to the thermionic diodes. With one reactor half anchored to the shield, the other is attached to a long arm with a pivot behind the shield and swings through a small arc for reactivity control. A safety shim prevents large reactivity inputs, and a fueled control arm drive shaft acts as a power stabilizer. Reactors fueled with U-235C and with U-233C have been studied.-
Li3W is Uranium Silicide-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Li is bonded in a distorted see-saw-like geometry to four equivalent W atoms. There are two shorter (2.70 Å) and two longer (2.77 Å) Li–W bond lengths. W is bonded to twelve equivalent Li atoms to form a mixture of corner and face-sharing WLi12 cuboctahedra.
Li3W is Uranium Silicide-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are two inequivalent Li sites. In the first Li site, Li is bonded to eight Li and four equivalent W atoms to form distorted LiLi8W4 cuboctahedra that share corners with twelve equivalent LiLi8W4 cuboctahedra, edges with eight equivalent LiLi8W4 cuboctahedra, edges with eight equivalent WLi12 cuboctahedra, faces with four equivalent WLi12 cuboctahedra, and faces with ten equivalent LiLi8W4 cuboctahedra. There are four shorter (2.70 Å) and four longer (2.91 Å) Li–Li bond lengths. All Li–W bond lengths are 2.91 Å. In the second Li site, Li is bonded in a square co-planar geometry to eight equivalent Li and four equivalent W atoms. All Li–W bond lengths are 2.70 Å. W is bonded to twelve Li atoms to form WLi12 cuboctahedra that share corners with four equivalent WLi12 cuboctahedra, edges with eight equivalent WLi12 cuboctahedra, edges with sixteen equivalent LiLi8W4 cuboctahedra, faces with four equivalent WLi12 cuboctahedra, and faces with eight equivalent LiLi8W4 cuboctahedra.