What is Nuclear Energy ?

This reaction has not been commercially developed yet and is a serious research interest worldwide, due to its promise of nearly limitless, low-pollution, and non-proliferative energy. Read more at our fusion page.

Energy densities of various energy sources in MJ/kg and in length of time that 1 kg of each material could run a 100W load.

Natural uranium has undergone no enrichment (0.7% U-235), reactor-grade uranium has 5% U-235. By the way, 1 kg of weapons grade uranium (95% U-235) could power the entire USA for 177 seconds. All numbers assume 100% thermal-to-electrical conversion. See our energy density of nuclear fuel page for details.

Table 1 sums the sustainability of nuclear power up quite well. However, there is quite a bit of talk about nuclear fuel (Uranium) running low just like oil.

Technically, this is a non-issue, as nuclear waste is recyclable. Economically, it could become a major issue.

Today’s commercial nuclear reactors burn less than 1% of the fuel that is mined for them and the rest of it or so is thrown away (as depleted uranium and nuclear waste).

The US recycling program shut down in the ’70s due to proliferation and economic concerns.

Today, France and Japan are recycling fuel with great success. New technology exists that can greatly reduce proliferation concerns.

Without recycling, the 2005 Uranium Reserves “Red Book” published by the U.N. IAEA suggests that there are over 200 years of Uranium reserves at current demand.

There is also a very large supply of uranium dissolved in seawater at very low concentration. No one has found a cheap-enough way to extract it yet, though people have come close. Nuclear reactors can also run on Thorium fuel.

In operation, nuclear power plants emit nothing into the environment except hot water. The classic cooling tower icon of nuclear reactors is just that, a cooling tower.

Clean water vapor is all that comes out. Very little CO2 or other climate-changing gases come out of nuclear power generation (certainly some CO2 is produced during mining, construction, etc., but the amount is about 50 times less than coal and 25 times less than natural gas plants. Details coming soon).

The spent nuclear fuel (nuclear waste) can be handled properly and disposed of geologically without affecting the environment in any way.

They’re safe too. In March, 2013 the former NASA scientist James Hansen (of the 350 ppm limit fame) published a paper showing that nuclear energy has saved a total of 1.8 million lives in its history worldwide just by displacing air pollution that is a known killer2. That includes any deaths nuclear energy has been responsible for from its accidents.

With nuclear power, many countries can approach energy independence. Being "addicted to oil" is a major national and global security concern for various reasons.

Using electric or plug-in hybrid electric vehicles (PHEVs) powered by nuclear reactors, we could reduce our oil demands by orders of magnitude.

Nuclear power is dirty, dangerous and expensive; not carbon-free; and encourages nuclear proliferation.

Additionally, many nuclear reactor designs can provide high-quality process heat in addition to electricity, which can in turn be used to desalinate water, prepare hydrogen for fuel cells, or to heat neighborhoods, among many other industrial processes.

A nuclear power station itself does not emit greenhouse gasses like CO2. Yet nuclear power contributes to climate change; with every step in the whole fuel chain, needed to generate electricity in the end, many energy is used.

When atoms split to release energy, the smaller atoms that are left behind are often left in excited states,

For instance, the extraction of uranium and the enrichment of uranium are extremely energy-intensive processes. Life-cycle analysis of the whole fuel chain clearly shows the contribution of nuclear power to climate change. In a ground-breaking study Sovacool et al screened 103 lifecycle studies of greenhouse gas equivalent emissions for nuclear power plants to identify a subset of the most current, original, and transparent studies.

emitting energetic particles that can cause biological damage.

Some of the longest lived atoms don’t decay to stability for hundreds of thousands of years.

This nuclear waste must be controlled and kept out of the environment for at least that long. Designing systems to last that long is a daunting task — one that been a major selling point of anti-nuclear groups.

They calculated that while the range of emissions for nuclear energy over the lifetime of a plant reported from qualified studies examined is from 1.4 grams of carbon dioxide equivalent per kWh (gCO2e/kWh) to 288 gCO2e/kWh, the mean value is 66 gCO2e/kWh.