Nuclear Waste Management: Celestial Solutions David Froot

Unaddressed Solution:  Many solutions to the nuclear waste issue: dilution and disperse, concentrate and confine, etc.  What about disposal of nuclear waste in space?  Is this a feasible solution economically and physically?

Economic Feasibility  Currently nuclear costs between 11.1 – 14.5 cents per kilowatt-hour.  One ton of Uranium produces 40 million kilowatt hours of energy.  New price of nuclear power per kilowatt hour is equal to original price plus cost of launching mass of uranium required to produce 1 kilowatt hour of energy into space. How much is this?

Price per kWh Approximately $10,000 to launch 1 pound of mass into space. 2,000 lb / 40,000,000 kWh = lb/kWh lb x 10,000 $/lb =.5 cents per kWh Only pushes price up from 11.1 – 14.5 cents to 11.6 – 15.0 cents per kWh: Economically feasible!

But what about the physics…  If the energy consumed by launching the nuclear waste into space exceeds the energy produced by that same mass, then the system does not result in a net energy gain, and is not a valid solution to the problem.  1 kg Uranium produces 3.26 x 10 ^10 Joules of Energy.  But how much energy does it take to put something into space?

 In theory, we need to achieve escape velocity for each kg of nuclear waste  The energy in 1 kg of nuclear waste at this speed is only 6.27 X 10 7 J, which is only.192% of the energy produced by same mass of equivalent uranium.  This is a gross under estimate because it completely neglects air resistance, fuel needs, etc. But this shows the theoretical minimum.  A more realistic solution… Which on earth is approximately 11,200 m/s

Look at the space shuttle for an idea… 1 st Stage Rockets: 1,000,000 kg of 31.0MJ/kg from Solid Rocket Boosters 2 nd Stage Rockets: 100,000 kg of 143 MJ/kg Liquid Hydrogen with liquid Oxygen as oxidizer Total Energy consumed by fuel = 4.53 x 10 ^ 13 J If the entire space shuttle were replaced by a nuclear waste container, it could launch 110,000 kg into space. Therefore at maximum efficiency, each kg would use approximately: 4.12 x 10 8 Joules Which is equivalent to only 1.2% of energy produced by the same mass of nuclear waste. Physically Feasible!

So why is no one considering this?  Yucca Mountain Nuclear Waste Facility holds approximately 2.25 x 10 9 kg at a cost of 8$ billion (so far), which means $3.55 per kg of waste (minimum)  Compare to $22,000 per kg ($10,000 per lb) of nuclear waste launched into space.

Sensitivity Study  How efficiently must we be able to launch waste into space to make it a viable option?  Each launch must cost only $390,500  Far, far too cheap.

Sources:    er_Kilowatt-Hourhttp:// er_Kilowatt-Hourhttp://  pers/FutronLaunchCostWP.pdf pers/FutronLaunchCostWP.pdf