the bombs to breed fuel for conventional fission reactors. In a 1975 review of the various Plowshares efforts, the Gulf University Research Consortium (GURC) considered the economics of the PACER concept. They demonstrated that the cost of the nuclear explosives would be the equivalent of fuelling a conventional light-water reactor with uranium fuel at a price of $328 per pound. Prices for yellowcake at that point were $27 a pound (), and were around $45 in 2012. GURC concluded that the likelihood of PACER being developed was very low, even if the formidable technical issues could be solved. The report also noted the problems with any program that generated large numbers of nuclear bombs, saying it was "bound to be controversial" and that it would "arouse considerable negative responses". In 1975 further funding for PACER research was cancelled. Despite the cancellation of this early work, basic studies of the concept have continued. A more developed version considered the use of engineered vessels in place of the large open cavities. A typical design called for a thick steel alloy blast-chamber, in diameter and tall, to be embedded in a cavity dug into bedrock in Nevada. Hundreds of long bolts were to be driven into the surrounding rock to support the cavity. The space between the blast-chamber and the rock cavity walls was to be filled with concrete; then the bolts were to be put under enormous tension to pre-stress the rock, concrete, and blast-chamber. The blast-chamber was then to be partially filled with molten fluoride salts to a depth of , a "waterfall" would be initiated by pumping the salt to the top of the chamber and letting it fall to the bottom. While surrounded by this falling coolant, a 1-kiloton fission bomb would be detonated; this would be repeated every 45 minutes. The fluid would also absorb neutrons to avoid damage to the walls of the cavity. See also Nuclear pulse propulsion Project Gnome Nuclear fusion-fission hybrid References Citations Bibliography External links Determination of main reactor parameters for flibe (Li2BeF4) cooled peaceful nuclear explosive reactors (PACER) (pdf) Ralph Moir's PACER page - contains a short summary and research papers about the topic Nuclear weapons testing Inertial confinement fusion Fusion reactors