5 key nuclear technologies that engineers are trying to make smaller

As the world seeks to limit the effects of climate change, engineers are racing to build small modular reactors and provide a vital boost to nuclear energy. Here are five of the technologies that engineers are trying to shrink.
Light-water reactors (LWRs) are the Toyotas of the nuclear fission industry. Tried, tested and reliable, they make up 80% of large-scale nuclear power plants around the world. Of the 55-odd reactors under construction, 49 are based on this technology.
LWRs rely on fissile chain reactions, with elements such as uranium and plutonium split apart to create heat, boil water, generate steam and turn turbines. Some compare it to boiling a kettle, but with nuclear reactions instead of electricity.