Posts Under: Nuclear Energy

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Renewable Energy Versus Nuclear Energy: Debunking the Myths

Renewable Energy Versus Nuclear Energy: Debunking the Myths

Posted on by in Blog, Nuclear Energy, Renewable Energy with Comments Off on Renewable Energy Versus Nuclear Energy: Debunking the Myths

When it comes to low carbon electricity, nuclear and renewable energy are the top competitors in most countries. But renewables often get a bad reputation because proponents of nuclear (typically nuclear energy companies) want to protect their bottom line.

There is a lot of misinformation about renewable energy perpetuating the media and the Internet. Today, we’re going to debunk these myths.

1.    Renewable Energy is Not Ready to Replace Fossil Fuels. Nuclear Is.

The majority of nuclear power reactors are classified as Generation 2. Generation 2 reactors are largely considered obsolete. New nuclear power stations are classified as Generation 3 or Generation 3+.

There are only four Generation 3 reactors in operation today, all of which are in Japan. Their performance has been unimpressive thus far. There are no Generation 3+ reactors operating today, but there are several under construction in the U.S., Europe and China. Unfortunately, these projects are all behind schedule and way over-budget.

solar-panels

It can be argued that nuclear energy is the one not ready to replace fossil fuels.

Wind and solar are seeing rapid growth and quickly becoming more affordable. Solar and wind farms can be planned and constructed in just 2-3 years and can easily replace fossil fuels right now.

2.    Renewable Energy Requires Huge Land Areas

It is true that on-ground solar farms and hydro-electric dams can occupy large areas of land. However, rooftop solar panels, which are highly prevalent in Australia and Germany, require no additional land.

On-shore wind farms are usually located on farms, and occupy just 1%-2% of the land. How much land they require will be dependent on the type of wind turbine. A horizontal-axis turbine typically requires less space than the vertical-axis design. These have two or three blades and operate upwind, meaning the blades face the wind (similar to how the flywheel works on a magnetic rowing machine like the ones here).

3.    Nuclear Energy Emits Virtually No Greenhouse Gas Emissions

It is true that nuclear energy and most renewable energies release no CO2 while in operation. However, when you compare the entire life cycle for nuclear (from mining raw materials to managing waste) to renewables, it’s easy to see that nuclear is far from eco-friendly.

According to Manfred Lenzen, life-cycle emissions for nuclear are around 60 grams of CO2 per kilowatt hour when using high-grade uranium ore. Natural gas produces 500-600 grams, while wind produces 10-20 grams.

Experts say there are only a few decades of high-grade uranium ore reserves left. Over time, the ore-grade will decline, making nuclear even less efficient. Mining will need to occur more frequently, which will require the use of diesel-fueled equipment. Greenhouse gas emissions will undoubtedly be higher.

Lenzen estimates that when low-grade uranium is in use, the life-cycle emissions for nuclear will increase to 131 grams per kilowatt hour.

4.    Nuclear Energy is a Great Partner for Renewable Energy

Proponents of nuclear energy argue that it can be used on the same grid with renewables, but the two are poor partners.

  • Nuclear reactors are inflexible in operation. Solar and wind can provide bulk energy, which can be balanced with dispatchable renewables.
  • Solar and wind farms are not as costly to run as nuclear plants.
  • Both nuclear and renewables often compete for support policies from governments, which can create a conflict of interest.
  • When nuclear power stations need repairs, the station is typically offline for months. Lulls in solar and wind are temporary and do not require backup from baseload power stations.

5.    The Nuclear Waste Storage Problem Has Been Solved

High-level nuclear waste is currently being stored in dry casks or pools. There are no permanent repositories in place anywhere in the world. The proposed storage repository at Yucca Mountain was canned after spending $13.5 billion. Finland and Sweden are currently working on underground repositories.

Even if a permanent storage solution can be found, there are still social and economic issues to consider, as the waste must be stored for 100,000 years.

Renewable energy, on the other hand, requires no permanent storage solution because it produces no waste.

Nuclear energy, while eco-friendlier than coal, still poses problems in the fight against climate change. Renewable energy is not perfect, but these myths are slowing progress in the industry, which could resolve these issues.

 

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How is Uranium Produced?

How is Uranium Produced?

Posted on by in Blog, Nuclear Energy, Radiation with Comments Off on How is Uranium Produced?

Uranium is an element which exists naturally in the Earth’s crust; specifically in sedimentary rocks, such as sandstone. In its elementary state uranium is only weakly radioactive due to its unstable isotopes, which vary naturally. Uranium ore must be mined and processed in order for it to be used commercially as fuel and in weapons.

Uranium ore is currently mined in around 20 countries, though more than half of the world’s supply of uranium comes from mines in just three countries: Australia, Canada and Kazakhstan. Other notable uranium producers include China, Namibia, Niger, Russia and the USA.

Mining

There are three methods of mining uranium: traditional open-pit mining, underground mining and in-situ leaching. Open-pit mining is only possible if the uranium ore is near the surface of the rock, and involves using machinery to remove soil and rock to reach the uranium ore deposits below. Underground mining is necessary where the uranium ore is too far underground to be reached by open-pit mining. The uranium ore is blasted and the resulting debris transported to the surface.

After both open-pit and underground mining, the uranium ore concentrated in the extracted rocks is weak, usually only around 0.3%. The rocks are crushed to a fine powder and added to water to create a slurry. The slurry is then ‘leached’ with sulphuric acid, or sometimes an alkaline solution if certain mineral rocks are present, to separate the uranium from the base rock.

In-situ leaching, known as in-situ recover mining in the US, has now become a more widely-used mining method, as it is more economical and environmentally friendly than open-pit or underground mining. In-situ leaching simplifies the mining process by essentially creating a slurry while the uranium is still in the ground. Heavily oxygenated water is pumped into a uranium well, dissolving the uranium but leaving the base rock intact. The water based uranium is then pumped back to the surface, where it’s already ‘leached’.

All three mining methods produce uranium suspended in liquid. The liquid is filtered and the uranium extracted from it by ion exchange to form a uranium oxide concentrate. This is a bright yellow powder, known as yellowcake. Yellowcake is only mildly reactive and must go through the enrichment process before uranium is usable in a commercial way.

To enrich the uranium oxide, it is first converted to gas, (uranium hexafluoride) though a process called calcining, essentially heating to a very high temperature. The gas can then be enriched to make it concentrated in uranium isotope 235, the isotope most needed for nuclear power. To do this, the centrifuge process is used, separating the uranium 235 from waste uranium by repeatedly diffusing the gas through a silver-zinc membrane in thousands of fast-spinning vertical tubes.

Once the uranium hexafluoride has been enriched, it is chemically converted to uranium dioxide powder. The powder is shaped into small cylindrical fuel pellets and heated to solidify them. The uranium dioxide pellets are slotted into thin tubes to form rods of fuel, which are grouped together to create fuel assemblies of several metres each.

Chernobyl
Chernobyl 30 Years On

Chernobyl 30 Years On

Posted on by in Blog, Nuclear Energy, Radiation with Comments Off on Chernobyl 30 Years On

On April 26, 1986, a horrific accident took place at the Chernobyl nuclear power plant located in Ukraine – part of the former Soviet Union. Originally there were four reactors and they were constructed between 1970 and 1983. The disaster at the Chernobyl plant was the worst of its kind in history, and even though the 30th anniversary of the tragedy is approaching, an exclusion zone (a radius of thirty kilometers) still exists around Chernobyl and public access is forbidden.

chernobyl powerplant

The nearest inhabited city was Pripyat and at the time of the meltdown it had 50,000 people, many of whom held jobs at the power plant. No one lives there now. What went wrong at Chernobyl on that day in 1986, and who was at fault?

Causes of the Accident

There was a special test scheduled, a low power test conducted to find out how long turbines would spin and give power to the main circulating pumps if the electricity supply were cut off. The test involved two steps: insert all control rods halfway to simulate a blackout, then disconnect one of the turbines and allow its inertia to generate power, which would be measured.

In a report published in August 1986, the blame for the Chernobyl incident was placed squarely on the workers who disabled the automatic shutdown mechanisms during the test. This was no doubt a mistake due to inexperience. However, new insights revealed that a bigger problem was the reactor itself, the Soviet RBMK-1000. This type of reactor differed from all other reactors in one key aspect: it used graphite as a moderator to continue a nuclear reaction in the core. At around 1:23 a.m. on April 26, extremely hot nuclear rods were placed in cool water, causing an incredible amount of steam. There was more reactivity in the core and this led to a power surge – a rather big one. An explosion blew the 1,000-ton plate off the top of the reactor and radiation made its way into the atmosphere. A second explosion spread burning graphite and damaged an adjacent reactor.

How the Accident Affected the Local Population

More than 100,000 people were evacuated from their homes in Ukraine, Belarus, and the Russian Federation. The people most affected were the “liquidators,” cleanup crews assigned to put out fires and bury radioactive materials. Unfortunately, they didn’t know what to expect until they were in the middle of the chaos, and unfortunately, weren’t fully recognized or fairly compensated for their work. Pripyat was emptied within three and a half hours, and no one has returned since.

It’s generally agreed that cases of thyroid cancer are greater in people who lived in the vicinity of Chernobyl when the reactor went up. Many of these individuals were children at the time.

Conclusion

The Chernobyl disaster is one of those traumatic events which is hard to come to terms with even after three decades. Authorities in Moscow were reluctant to admit the RBMK-1000 reactor was flawed, and this was due to a culture of secrecy that existed in the Soviet state. Pripyat is now marketed as an “extreme destination,” where, in the absence of humans, nature has started to take over the deserted community.