Energy Return for nuclear energy

Life cycle energy and greenhouse gas emissions of nuclear energy: A review by Lenzen is fairly frequently quoted for its energy return analysis of nuclear energy. Lenzen had calculated nuclear energy return at 3-10 times the energy input.

Lenzen assumes nuclear plants have an operating life of 25-45 years. Many nuclear plants are heading to extended operations of 60-80 years.
Lenzen assumes that enrichment is at 2 to 2.5 times more costly in electrical energy than it is. They then scale up the energy costs with other factors.
Lenzen converts his numbers to kwh of energy needed per kwh hour generated but does not have a clean breakdown of the input energy contributions. Lenzen then converts it do carbon dioxide contribution based on some greenhouse gas intensity of whole economy.

Lenzen is easily 6 times too high in the energy costs on those factors. I think the nuclear energy return is at 60 and will be increasing with more efficient enrichment, more efficient operation and other improvements like annular fuel.

The Lenzen paper talks favorably about the Storm van Leeuwen and Smith work.

Storm van Leeuwen and Smith is biased.

Almost all of the EROI literature is littered with academics with an agenda. They do a lot of referencing each others work.

There was a 15 page critique by Dones that explained problems with Storm van Leeuwen and Smith greenhouse gas and energy analysis.

Enrichment energy

Lenzen had the following energy efficiency for centrifuge and laser enrichment. 100 kwh per SWU.

Most centrifuges require only about 50-60 kWh per SWU.

Urenco indicates modern centrifuges need 40 kWh per SWU.

Laser enrichment is being commercialized by GE and is 3-10 times more efficient than gas centrifuges

So Lenzen is 2.5 times too high on the energy cost for enrichment today and will be 7 to 25 times too high going forward.

Decommissioning nuclear plants 25% cheaper

Commonwealth Edison, now part of Exelon, is trying out a radical new approach to decommissioning nuclear plant that promises to make the process faster, simpler and 25 percent less expensive — instead of hiring a contractor, it has turned the job and the reactors over to a nuclear demolition company that owns a nuclear dump site. The cost will be covered by the $900 million that Exelon accumulated in a decommissioning fund.

If the approach is successful, it could have implications for 10 other nuclear plants around the country that are waiting to be decommissioned, and for the 104 reactors that are still in operation but will eventually be torn down. It will also save money for electricity customers, who often end up paying for the cleanup of nuclear plants through their utility bills.

The decommissioning operation at Zion, which began on Sept. 1, will skip one of the slowest, dirtiest and most costly parts of tearing down a nuclear plant: separating radioactive materials, which must go to a licensed dump, from nonradioactive materials, which can go to an ordinary industrial landfill.

The new idea is not to bother sorting the two. Instead, anything that could include radioactive contamination will be treated as radioactive waste.

Nuclear waste is mostly unburned fuel

Nuclear waste is almost all unburned fuel. New deep burn reactors should be built to use up all of the unburned fuel. There is also offsite reprocessing that can be combined with current generation breeders to enable a closed fuel cycle. China is looking to scale up the breeder-offsite refueling method to close the fuel cycle. Closing the fuel cycle means that long term storage costs and complexity is avoided.

Energy return for nuclear energy is more like 60 times and rising with new technology

The World nuclear association has a detailed analysis of energy return and has a conservative estimate of 59.

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