how does the energy spent in enrichment of nuclear fuel compare to the energy released by its fission for the same amount?
In: Physics
I’ll leave the exact amounts to a nuclear expert, but I’m guessing the gist of your question is how economical is producing nuclear energy. Nuclear energy is about 8000 times more economical than fossil fuel production, *once it’s up and running*. Originally it was thought that nuclear power would be “too cheap to meter”, meaning they considered just making it free. The problem began with construction. Building nuclear power plants now cost upwards of $9 billion according to a report ten years ago (up from between $2B – $4B), and I’m guessing that’s gone up in the last decade. Lots of original projects to build were abandoned because of out of control costs to build.
The second cost is managing the spent materials. There’s really no great answer. Initially spent rods are place in cooling pools for 10-20 years and then into dry storage, for (I believe) around 60 years. I’m not sure what happens after that, but as you can see, the method of “kicking the can down the road” is troubling from a safety point of view and an obvious financial one.
Since the rods are still in the fission stage, the water molecules can be split creating hydrogen explosions so there’s a lot of monitoring of the air, water, and just about everything. There’s some research that sees turning that problem into a resource, potentially creating hydrogen fuel from the process, but I have no idea where that research is as far as it becoming a practical idea.
So, as you can see, your question about how much energy is required to produce fission *must* include building the reactors and dealing with the cleanup makes it very hard to truly know the actual cost per kilowatt hour, or as you’re looking for (I think), a ratio of energy spent to energy created.
Some believe nuclear power to be the ultimate “green” energy, but 3 Mile Island, Chernobyl and Fukushima have shown that the potential for disaster negates creating an otherwise enormous source of energy. It’s the ultimate trade off.
I’m hoping someone who knows a lot more than me can chime in on the actual ratio of energy spent to energy created, but in my estimation, unless you count the cost and energy of all stages, it’s not an accurate measurement.
Uranium enrichment costs roughly [50-60 kWh per kg](https://energyeducation.ca/encyclopedia/Uranium_enrichment). 1 kg of enriched uranium can produce up to [24 million kWh](https://www.euronuclear.org/info/encyclopedia/f/fuelcomparison.htm) of energy through fission. So the ratio is approximately 500,000 to 1. This doesn’t take into account inefficiencies in the reactor or additional energy spent on related activities, but it’s hard to imagine those would account for more than a hundredfold decrease, which would still give a ratio of 5,000 to 1.
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