Overcoming Mythology - Real Analysis Regarding Carbon Intensity of Uranium Fuel Cycle
- Jan 18, 2011 5:56 pm GMTJul 6, 2018 9:48 pm GMT
- 364 views
It might surprise many people who are not actively involved in discussions about our energy future, but there is a persistent myth that comes up with depressing regularity regarding the carbon dioxide emissions associated with various energy sources. The myth is that nuclear power plants – which produce electricity by converting uranium fission heat into mechanical energy through a conventional steam cycle system – are somehow prodigious producers of carbon dioxide.
Not only do I know how to do the chemical and nuclear balanced equations to see that fission does not release any CO2, but I used to spend months at a time sealed up inside a submarine with an operating reactor that had no smokestack or means of discharging any gases. Theory and practice both support my gut feeling that nuclear energy is an emission free source of power.
However, in internet conversations with advocates of other types of energy who are often viscerally opposed to the use of fission, I have continually run into people who make rather vague assertions about all of the fossil fuel that is used in mining for uranium, enriching the fuel, fabricating the fuel rods, and transporting the fuel. They also talk about the energy required to manufacture the concrete, the steel, and the other raw materials associated with constructing the plant. Then they claim that there is an uncounted amount of energy associated with the process of decommissioning the plant after it has served its useful life.
After a number of engagements with people who were unable to provide numbers to support their assertions, I began to realize that part of the argument was quite emotional. Many of the people who actively promote non nuclear alternatives to fossil fuel find it very inconvenient to acknowledge that one of their main selling points – lack of emissions – is shared by a far more capable and reliable non fossil fuel alternative.
The organized forces that oppose nuclear energy apparently recognized that vague arguments did not provide them much cover, so they have worked hard to find and promote studies that “proved” or documented substantial quantities of CO2 in various portions of the nuclear fission power lifecycle. People like Jan Willem Storm van Leeuwen and Benjamin Sovacool have produced frequently referenced papers that attempt to provide hard numbers – but whose methodologies have been frequently called into question by capable and qualified observers. (Hat tip to Charles Barton at Nuclear Green for this link.)
Often, the arguments have devolved into something akin to “he said, she said”, though people with reasonably good technical backgrounds and critical reading skills can readily determine which side of the argument is real and which side is propaganda. Unfortunately, hard-nosed analysis that is not a survey of other people’s assertions is often hard to come by. It exists, but it has often been done by sources that are dismissed out of hand. For some reason, the environmental reports of corporations like Vattenfall is not seen as a credible source of information, even when certified by an outside regulator.
Yesterday, however, I received a document titled Measures of the Environmental Footprint of the Front End of the Nuclear Fuel Cycle, dated August 23, 2010. The document was prepared for the U. S. Department of Energy and has an identification number of FCRD-SYSA-2010-000104. I have not yet been able to locate the document in a publicly accessible archive, but I will keep trying. In the meantime, I thought it would be worth while to provide some information from the executive summary of the 115 page, meticulously documented study.
Front End Fuel Cycle CO2 Emissions, 2050 Scenarios kg CO2/MWh(e)
|Current||2050 Low||2050 High|
|Fuel Fab (UOX)||0.09||0.02||0.06|
Source: Schneider, Carlsen, Tavrides, Measures of the Environmental Footprint of the Front End of the Nuclear Fuel Cycle, dated August 23, 2010, Idaho National Laboratory
Though this study focuses on just the fuel cycle, it provides valuable support for the assertion that atomic fission is virtually emission free. It also provides a substantial amount of support for the assertion that nuclear fission is sustainable and has a very high Energy Return on Energy Invested (EROI) According to one of the tables in the study, the fuel cycle requires the energy investment of just 0.0085 GJ(e)/MWh(e) plus 0.029 GJ(t)/MWh(e).
Here is a quote from the executive summary:
With the exception of water use, these impacts are very favorable relative to other competing technologies for large-scale energy production. For example, front-end processes have been estimated to account for 38% of the carbon footprint associated with production of electricity from nuclear energy. Scaling the above estimate for FEFC emissions accordingly, one estimates 7.4 kg CO2/MWh(e) for nuclear electricity production . For comparison, current average U.S. emissions from natural gas and coal-fired electricity production are 410 and 979 kg CO2/MWh(e), respectively.