The NERVA engine [1], [2] used 60kg of 92.5% enriched Uranium. The online nuclear fuel cost calculator [3] shows that at current Uranium market prices, the cos

The NERVA engine [1], [2] used 60kg of 92.5% enriched Uranium. The online nuclear fuel cost calculator [3] shows that at current Uranium market prices, the cost for 1kg of such highly enriched Uraniums is about $50k, so the whole engine core would come at about $3 MM. This engine had a weight of about 2.5 metric tons, a thrust of 75 kN and a specific impulse of 860s. For comparison, the weight of a SpaceX Raptor engine is about 1.5 tons, it has a thrust of 1.8 MN (24 times higher than Nerva) and a specific impulse of 360 s (2.4 times lower than Nerva's). [1] https://en.wikipedia.org/wiki/NERVA https://en.wikipedia.org/wiki/NERVA [2] http://www.astronautix.com/n/nervaalphaengine.html http://www.astronautix.com/n/nervaalphaengine.html [3] https://www.uxc.com/p/tools/FuelCalculator.aspx https://www.uxc.com/p/tools/FuelCalculator.aspx