Lean Processing of Plutonium 238

Reduced Cycle time, reduced inventory and continuous flow in the production Plutonium 238.

I’m an avid reader of New Scientist and this made me smile(You will need to create a user account on New Scientist to read the article).

Basically NASA is going to run out of Pu 238 within 10 years, which they need to power deep space craft like voyager, Cassini etc.

Why?

Because Pu 238 traditionally has been a by-product of making weapons grade fissile materials, which we don’t do any more. 

 

(Reproduced from Page 6 of http://www.nasa.gov/pdf/636900main_Howe_Presentation.pdf)

The options open to NASA are an entirely new energy source (Unlikely in the time they have) Better solar (Bearing in mind a probe that generates its required power via a 1 m2 solar array in earth orbit would require a 2000 m2 solar array by the time it gets to Pluto!) or restart Pu 238 production.

Traditionally this is done by “soaking” a big lump of Np 237 (Neptunium) in a reactor kicking out a bunch of Neutrons that bombard the 237 turning it into 238.

This takes a BIG reactor about 6 to 12 months to perform (Think Big set up costs – Huge reactor cores, All the Big Infrastructure projects of the 60’s USA)

Or there is this proposal (The report the graph above is from) which on Page 13 describes creating the plutonium in a small university sized reactor core using small pellets of Neptunium – Basically reducing Cycle time, reducing inventory and using continuous flow in the production Plutonium 238 to increase delivery and lower costs.

In some ways could be considered a lean processing of Np 237 to Pu 238.

Why bother?

Well when NASA were buying Pu 238 from the Russians the market rate was about $12m / Kilo (Gold / Kg is approx . 51,000 USD making Pu 238 about 244 times as valuable as gold.) 

 

August 14 2012
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