At present consumption rates, reactors could run for more than 200 years if the Nuclear Energy Agency (NEA) had properly calculated the planet's commercially available uranium supplies. But its estimate of these resources was based on old data that is now considered unreliable. Further, some countries hold back their reserves to keep prices low, so they will not be available for future generations.
The world's estimated remaining uranium supply can be divided into three categories: proven reserves, probable reserves, and possible reserves. Proven reserves are estimated to be about 740 million pounds (340 kg) out of a global total of 1.5 billion pounds (700 kg). Probable reserves amount to another 1.4 billion pounds (650 kg), while possible reserves remain only at the surface of the earth after mining.
After World War II, when uranium was still relatively cheap, many nations built large numbers of nuclear power plants. This popularity + the shortage of this kind of energy made it easy to find investors who wanted to build plants. In addition, electricity from nuclear power is not dangerous for production purposes, which means that there are no safety concerns for using this type of energy in factories. This is why most countries around the world have switched to nuclear power as their main source of electricity.
According to the NEA, known uranium deposits number 5.5 million metric tons, with a further 10.5 million metric tons yet undiscovered—a total supply of around 230 years at today's consumption rate. The amount of energy that could be produced from all this uranium is about 7.6 billion megawatt-years.
Uranium has been used as a nuclear fuel because it can produce large amounts of energy per unit mass. A typical reactor uses uranium oxide pellets, but reactors have also been built using enriched uranium (material with a higher concentration of uranium-235 than naturally occurring uranium) or plutonium (one atom of plutonium produces as much energy as two atoms of uranium-235). Enriched uranium is more expensive but also lasts longer; a typical power plant should generate enough material for about five years of continuous operation. Plutonium reactors are rare but may become important if commercial uranium enrichment techniques are not developed soon.
In 2010, the NEA estimated that the worldwide average production and consumption of electricity was about 14 trillion watts. This means that about 1.4% of the world's uranium reserves would last for more than 40 years. However, high levels of electricity usage increase radioactive decay rates so some uranium will be lost before then.
About 21% of the world's uranium reserves were estimated to be located in Canada.
Nuclear reactors are extremely dependable in generating power, capable of running continuously for months, if not years, regardless of weather or season. Furthermore, most nuclear reactors can operate for very long periods of time—in many cases, more than 60 years. This makes them particularly useful when the need for power is constant rather than seasonal.
All commercial nuclear reactors operate on a cycle that includes an active period and a shutdown period. During their active periods, they produce energy by fissioning uranium atoms inside the reactor core. Each time a reactor operates, some of its components become radioactive and have to be replaced over time. They include water pipes, control rods, and fuel assemblies. The average lifetime of a nuclear reactor is about 20 years.
During their shutdown periods, reactors cool off by drawing air through the core. This causes any remaining uranium atoms in the core to decay, producing more harmless radon gas. Shutting down the reactor also allows any damage to the reactor's internal structure caused by excessive heat during operation to heal itself. A reactor's lifespan can be extended by using passive cooling systems such as water tanks or pumped ice beds. These systems are used primarily for research reactors which are designed to generate enough heat energy to allow scientists to study materials that would otherwise be destroyed by too much heat.
In conclusion, nuclear reactors are very reliable and able to produce energy year-round.
Units 3 and 4 of the Turkey Point facility in Florida were the world's first reactors to be licensed for 80 years of operation in 2019. The reactors at Fukushima had operated for nearly 10 years when they were damaged by the 2011 earthquake and tsunami.
Nuclear power plants are built to last about twenty-five years. In fact, this is often an estimate of the life span of a plant's concrete containment structure. The core of the reactor itself will require replacement every few years.
When you add up the hours of operation over their lifetime, the average nuclear reactor produces approximately 7 million kilowatt-hours of electricity per year. This amount is enough to light about 70 homes during peak sunlight hours in northern California. One large nuclear plant has the potential to save nearly $300 million in costs related to energy consumption and production.
In addition to being efficient and sustainable, using nuclear energy is safe. No one has ever died from a nuclear accident. There have been no reported incidents of cancer caused by radiation exposure from nuclear power plants.
Nuclear energy is dangerous only if it's mishandled. And since these plants are designed to fail safely, there is little chance of someone being injured by them.
From 1981 to 2019, the typical construction period for nuclear reactors globally ranged from roughly 84 months to 117 months. Construction periods were longest for pressurized water reactors, which can cost up to $5 billion and take about 1.5 years to complete. Construction periods were shortest for boiling-water reactors, which can cost under $1 billion and take only about nine months to finish.
In general, building a nuclear reactor requires extensive planning and preparation that includes research and development, design, procurement, construction, installation, testing, qualification, licensing, maintenance, and decommissioning. The amount of time required for each step will vary depending on the reactor type and country of operation.
Nuclear energy was first developed in the 1940s and 1950s and has been used in power plants ever since. Although plans to build new nuclear power plants have been announced by several countries around the world, none have yet started construction.
Some countries may need more than one attempt to start a construction project before they give up. For example, China tried to start three different projects in 1994, 1998, and 2014 but had to stop them all due to technical difficulties and high costs.