nuclear-news

 With environmental considerations constraining the further development of hydro-electric sources, nuclear technologies continue to present an option for future reliable energy that can be readily dispatched into the market.

This sentence appears in a passage dealing with the “move to low-emissions energy”, and although nuclear is not explicitly described as a low-emission option, it certainly looks as if the government is prepared to consider embracing nuclear power as part of an alleged move away from fossil fuel

Is nuclear energy really low-emission?

Unfortunately, the notion that nuclear energy is a low-emission technology doesn’t really stack up when the whole nuclear fuel life cycle is considered. In reality, the only CO₂-free link in the chain is the reactor’s operation. All of the other steps – mining, milling, fuel fabrication, enrichment, reactor construction, decommissioning and waste management – use fossil fuels and hence emit carbon dioxide.

Several analyses by researchers who are independent of the nuclear industry have found that total CO₂ emissions depend sensitively on the grade of uranium ore mined and milled. The lower the grade, the more fossil fuels are used, and so the higher the resulting emissions.

In one such study, the nuclear physicist (and nuclear energy advocate) Manfred Lenzen found that CO₂ emissions from the nuclear fuel cycle increase from 80 grams per kilowatt-hour (g/kWh) where uranium ore is high-grade at 0.15%, to 131 g/kWh where the ore grade declines to low-grade at 0.01%.

Other experts, such as nuclear energy critics Jan Willem Storm van Leeuwen and Philip Smith, using assumptions less favourable to nuclear energy, have reported an increase in emissions from 117 g/kWh for high-grade ore to 437 g/kWh for low-grade ore.

For comparison, the life-cycle emissions from wind power are 10–20 g/kWh, depending upon location, and from gas-fired power stations 500–600 g/kWh. So depending on your choice of analysis, nuclear power can be viewed as almost as emissions-intensive as gas.

Making the grade

The quantity of known global uranium reserves with ore grades richer than the critical level of 0.01% is very limited. With the 2013 contribution by nuclear energy of about 10% of the world’s electricity generation, the high-grade reserves would at best last several decades. It doesn’t make sense to invest vast amounts of money in a technology that will emit more and more CO₂ over time.

Are there alternative future pathways for obtaining nuclear fuel that could have lower emissions? Although there are vast quantities of uranium oxide in the Earth’s crust, almost all of such reserves exist at very low concentrations, typically 0.0004%. At this grade, 1000 tonnes of ore would have to be mined to get 4 kilograms of uranium in the form of yellowcake.

In this case the energy needed to extract uranium would be orders of magnitude greater than the energy output of the nuclear power station. There is a limit to how much the uranium industry can be expected to chase diminishing returns. For instance, seawater contains uranium, but at a concentration of about 0.0000002%, meaning that a million tonnes of seawater would have to be processed to extract just 2 kilograms of uranium.http://theconversation.com/sure-lets-debate-nuclear-power-just-dont-call-it-low-emission-21566