Energy Payback Times for Nuclear

Last Sunday, Palm Beach Post wrote an article about students from Florida Atlantic University protesting FPL's nuclear plant expansions. What struck me about the article was this claim made by the anti-nuclear energy group - Nuclear Information and Resource Service:

A nuclear power plant takes so much water and energy to build, it has to run for 15 years to offset its carbon footprint, according to the nonprofit group, the Nuclear Information and Resource Service. Mary Olson, director of the organization's southeast office, was a summit keynote speaker.

Fifteen years? I don't think so. This claim appears to be apart of the whole lifecycle emissions claim we’ve dealt with from Storm van Leeuwen and Smith. The two have claimed that nuclear’s lifecycle emissions are comparable to a gas plant based on the energy requirements at each stage of a nuclear plant’s cycle. In SLS' study, they mis-calculate the energy payback time for a nuclear plant at 10-15 years.

What's the real energy payback time?
The NIRS claim above confuses three different subjects – water consumption, energy and carbon footprint. The debate really centers on how much energy nuclear plants consume during the front and back-end of the fuel cycle, and during construction and decommissioning of the plant. The water consumption and carbon footprint claims are based off of how much energy a nuclear plant consumes during each of these stages.

According to Table 2 in this link from the WNA, the estimated amount of energy from all stages of a nuclear plant using centrifuge enrichment technology for uranium is about two percent of a nuclear plant’s lifetime energy production. This means that if a nuclear plant runs for 40 years, it will take about 10 months of operation for a nuclear plant to offset its energy from all of its other stages. If a nuclear plant uses diffusion enrichment technology for uranium (much more energy intensive), then it would take about 2.4 years to offset its energy. Since the U.S. and world are moving towards centrifuge enrichment technology, it is reasonable to say a nuclear plant takes about one year to offset its energy consumption from its other stages.

Research on NIRS
I was almost positive the NIRS claim above came from Storm van Leeuwen and Smith. But to be sure, I went through NIRS’ website and found this webpage by Mary Olsen discussing nuclear's CO2 emissions. Here’s her quote on the issue:

A number of recent studies have found that when mining, processing, and extensive transportation of uranium in order to make nuclear fuel is considered, the release of carbon dioxide (CO2) as the result of making electricity from uranium is comparable to burning natural gas to make electric power. [6] Additional energy required for decommissioning and disposition of the wastes generated increases this CO2 output substantially.[7]

I went to both of the cited studies and found nothing to back up NIRS' claim. Here's what the study for their sixth citation actually stated on page 25 (pdf):

In summary, nuclear power could contribute to a certain extent to ambitious emissions reduction targets at the global level.

This statement is a bit contradictory for NIRS since they are trying to say nuclear can't make a difference in reducing emissions.

The study for the seventh citation made no mention of nuclear's lifecycle emissions either. It was also a study we debunked back in the day. (If anyone would like to check my claim, use key words like uranium, natural gas, transportation, emissions etc. to search efficiently through the two cited documents.)

What’s interesting is the NIRS claim is exactly the same claim from Storm van Leeuwen and Smith, yet there is no citation anywhere for SLS. If you go to page 20 of SLS' Part C (pdf), you can see that NIRS chose the lowest line on the chart to show the energy payback time for nuclear at about 15 years. If you go to Chapter 1 on SLS' home page, you can find the same gas and nuclear lifecycle emissions comparison as claimed above by NIRS.

Why didn't NIRS cite SLS? Maybe NIRS is trying to distance themselves from SLS because they know SLS is no longer credible. So what does NIRS do? They cite two studies that don't verify their statement, claim the statement is backed up by “a number of recent studies,” and then hope nobody checks their sources. Only antis could get away with such deceit.