Dr. Jim Conca recently published an article titled What’s Better? A Carbon Tax or Energy Subsidies? for his column on Forbes.com. I invited him, along with Cal Abel, a nuclear engineering PhD candidate at Georgia Tech with a strong interest in energy economics, for a chat on the Atomic Show.
We got a little off topic at times, but I think you will find the discussion thought provoking and worth a listen.
Podcast: Play in new window | Download (Duration: 1:09:03 — 31.6MB)
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Rod – any chance we could see a picture of your fuel pellets that you mention in the show? … and what are their dimensions and weight?
Just interested
All the best
You can buy a simulated fuel pellet from ANS http://www.new.ans.org/store/i_750027
Oh that’s great thank you.
I’m was trying to get numbers for mass density. Do these sound about right
uranium metal 19g/cm3
uranium oxide fuel pellet 10g/cm3
uranium fuel rod 10g/cm3 (about the same, cladding doesn’t contribute much)
yellow cake 10g/cm3
uranium ore – varies massively perhaps 5g/cm3 (denser than most rock which is usually 2-3g/cm3)
I think yellow cake is actually 2g/cm3
The Wolfram Alpha site will allow you to enter in chemical formulas. I typed in “density of U3O8” and here’s what I got:
http://www.wolframalpha.com/input/?i=density+of+U3O8
Much appreciated. I did try that, but there are conflicting numbers over the internet. So I thought I’d ask. Maybe yellowcake, as it is transported, is a long way from being pure U3O8. I don’t know. If there’s anyone from Kazakhstan who could help me out…
As for the density of a uranium fuel pellet, sorry if I’m a little late to catch on to this, but if uranium dioxide is 10g/cm3
and a fuel rod is 4m long and cross section of 1cm3
then a fuel rod weighs about 4kg
of which about 3% is U235
which is 120g of U235
which contains (6 x 10^23) x (120/235) atoms of U235
which equals 3×10^23 atoms of U235
which when fissioned gives off (3×10^23) x (200 Mev) x (1.6×10^-19 J) / 3.6×10^6 kwh
which, with a thermal efficiency of about a third, gives about 1 million kwh of electricity.
(not all U235 is fissioned in a fuel rod, but that which isn’t is made up for by Pu239)
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in the USA you use about 12-13,000 Kwh of electricity per capita per year.
or 1 million kwh per lifetime.
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which means if USA was 100% nuclear, when you shuffle off this planet, after a lifetime of electricity consumption, all you would leave behind you is one sole uranium fuel rod.
Personally, I find that not only amazing but quite beautiful. I would quite like my name engraved in “my” fuel rod before it is put in a reactor, be allowed to go and visit it when it is in spent fuel pool, and finally be present to give thanks and pay my respects when it goes into dry cask storage. It has, after all, done far more work than I ever did.
…it certainly sounds much better than leaving behind 1000 tonnes of supercritical CO2 in some CCS salt dome. Fission is the new fire as someone likes to say.
10 gm/cm3 is about right for the fuel pellet
“which means if USA was 100% nuclear, when you shuffle off this planet, after a lifetime of electricity consumption, all you would leave behind you is one sole uranium fuel rod.”
So if the US went 100% nuclear fission, there would be 300 million fuel rods to deal with. This does require a certain amount of organisation.
From the point of view of the power companies, the end products from burning gas just blow away, and need no storage or handling. The companies are not bothered about climate change. Not their problem. If temperatures do go up, it increases the sales of power for air conditioning.
One can see the attraction of gas.
hmm it seems to have had the opposite effect on you.
I thought 1 fuel rod per person per lifetime to be quite impressive. My bones would take up more room.
Not to think of all the non biodegradable waste each of us leave behind at the end of our lives.
http://en.wikipedia.org/wiki/Great_Pacific_Garbage_Patch
Any modern society composed of 300 million people is going to require a certain amount of organization. Keep in mind that’s over the span of 78 years (the average life span in the US). Mankind has known about the neutron for only 80 years.
A fuel rod might seem like a lot of material, because of its length, but that’s misleading. The volume of one rod is about the same as the volume of a standard soft-drink can or less, depending on the design. A single 8.5″×8.5″×13.3′ Westinghouse fuel assembly holds 264 of these rods.
To give you some perspective, in just 2011 alone, Americans purchased over 9 billion cases (not cans) of carbonated soft drinks.
T Boone Pickens wants to convert all vehicles engine to natural gas … He also admitted yesterday that he ‘lost his shirt with wind and that it will never work’.
I agree. Since USA started making nuclear electricity commercially it has produced approx. 25 trillion kwh of electricity.
With my new-found calculation tool. I can quite easily say that it has produced in the region of 25 million spent fuel rods. If you were to store those end on then it would fill 50metres x 50metres (and 4metres high). Half the size of a football pitch and just above the height of the goal posts.
If you were to put them in dry cask storage. I think the area required would go up by a factor of 20. And so 10 football pitches covered with these.
and those 10 football pitches would take up less room on this map than one of those dots.