- How does nuclear power work?
- What are small modular reactors?
- How much power can small modular reactors produce?
- Are nuclear reactors safe?
- Why aren't small modular reactors more common in the U.S.?
- Do small modular reactors create pollution?
How does nuclear power work?
While there are many nuances as to how nuclear fission works, the essential steps are as follows. Nuclear fuel rods, typically made of a specific type of uranium formed into small pellets and kept in metal rods, are used to create a fission reaction in which atoms are broken apart into smaller atoms, releasing large amounts of energy in the process. The fuel rods are kept within a reactor core and inserted or withdrawn from the core to decrease or increase the amount of reactions. As the reactions occur, heat is generated, which then turns water into steam, spinning a turbine to generate energy which is then put onto the electrical grid.
What are small modular reactors?
Essentially, a small modular reactor (SMR) is a shrunken down and self contained version of a traditional nuclear reactor. Like a traditional nuclear reactor, SMRs utilize fission reactions from uranium to produce power, splitting one large uranium nucleus into two smaller nuclei. What makes SMRs unique, besides their smaller size, is the fact that their parts can be prefabricated whereas traditional nuclear plants often have their parts custom made. Because of this, SMRs could theoretically be mass produced at a fraction of the cost that traditional nuclear facilities run. Several could then be placed at a single site and provide similar levels of power to traditional reactors, or a single SMR could be placed near an area with high local power demand from things like a data center, military base, or isolated town.
How much power can small modular reactors produce?
According to the International Atomic Energy Agency (IAEA), to be considered a small modular reactor, a SMRs highest production capacity must be 300 megawatts (MW) or lower. Comparatively, a traditional reactor can generally produce around 900 MW of power at their highest capacity (though this can vary depending on the reactor). Some SMRs may produce as little as 10 MW of energy at maximum capacity.
Are nuclear reactors safe?
While nuclear disasters can have devastating tolls on both humans and the environment (i.e. Chernobyl, Fukushima, etc.), it is important to remember how uncommon they really are. The most recent major nuclear incident on US soil was in Pennsylvania in March of 1979, during an event known as the Three-Mile Island incident. During that incident, the nuclear station had a partial meltdown resulting in roughly 2 million people being evacuated from the surrounding area. Fortunately, the average dose of radiation that individuals received was only around 1.4 millirem (mrem). To put that into perspective, an x-ray provides a dose of around 6 mrem and the average person is exposed to 620 mrem annually from natural and man-made sources.
Many of the lessons learned since nuclear power began use can be applied to SMRs as well. Beyond the typical nuclear safety measures like control rods and active cooling, most SMR designs incorporate passive safety systems. These systems, in theory, would provide a way to automatically shut down the reactor without any need for human intervention.
The International Atomic Energy Agency (IAEA) is responsible for reviewing current nuclear safety standards to determine what must change to accommodate this new style of nuclear generation.
Why aren't small modular reactors more common in the U.S.?
SMRs are still in the research and development phase. The first SMR design approved by the U.S. Nuclear Regulatory Committee (NRC) was approved in early 2023 but has yet to be built. Understandably, the relatively new and untested SMR designs are under a lot of scrutiny as they are developed. Nuclear safety precautions and standards must be updated and adjusted to accommodate these new designs.
Do small modular reactors create pollution?
It’s expected that SMRs, just like their larger counterparts, will not produce CO2 or other greenhouse gasses when operating; however, their spent fuel will be radioactive waste that must be carefully handled and disposed of. Whether or not SMRs produce more, less, or comparable amounts of radioactive waste is under debate, largely due to the fact that, as of 2024, no SMR has been built in the US or anywhere else in the world. A 2022 study from Stanford University did indicate that NuScale’s SMR design would produce more radioactive waste than traditional reactors; however, representatives from NuScale, a leading company in SMR development, claimed that the data used in the study was out-of-date and inaccurate.
As SMR designs are approved and built, it will become clearer where they stand in terms of amounts of pollution being produced in comparison to one another, and traditional nuclear overall.
