Since 1975, all of the submarines built for the U.S. Navy have been nuclear powered. Given the complexity of a nuclear reactor and the risk to human health, you may be surprised to hear that submarines can contain a nuclear reactor.
Read about nuclear powered submarines.pdfStart by reading this article about how a nuclear reactor is used to power a submarine. Consider how nuclear reactors have to be designed or used differently when built on land vs. as part of a vessel or vehicle.
Q: Why is nuclear power a better option for submarines?
Submarines try to stay very quiet to avoid detection by SONAR. Therefore, they need to travel submerged as much as possible. A combustion-powered engine requires the submarine to surface frequently or "snorkel" to swap carbon dioxide for oxygen to keep combustion going. Nuclear engines can stay submerged much longer (the humans are the reason they need to surface!)
More details (optional video): https://www.youtube.com/watch?v=AHIGMSQtF4E
Q: Who leads the nuclear power program for the Navy?
Scientists and engineers, including those in service and civilians.
"The Naval Nuclear Propulsion Program provides militarily effective nuclear propulsion plants and ensures their safe, reliable and long-lived operation. This mission requires the combination of fully trained U.S. Navy men and women with ships that excel in endurance, stealth, speed, and independence from supply chains." From Powering the Navy.
Their responsibilities include developing and maintaining the technology as well as protecting the health of people and the environment that could be hurt by radiation.
How can submarine crews sail with a nuclear reactor onboard??
Each reactor compartment contains over 100 tons of lead shielding. Shielding is protective layers that stop radiation. With ultraviolet radiation (which is a much lower energy form of radiation), we use shielding everyday, such as wearing a hat or putting on sunscreen. Nuclear reactors give off alpha, beta, and gamma electromagnetic radiation. Gamma radiation is the highest energy and requires the thickest shielding, such as thick cement walls, lead, or steel.
Image Credit : Nuclear submarine at FAS website
Comprehension Check
1. What is "shielding" and why is it important?
2. What are some of the differences between a nuclear reactor that is land-based compared to one on a submarine?
3. When a submarine is decommissioned, the reactor compartment is used to house some of the waste. Eventually, even the reactor compartment will corrode and release its contents. Why is that not a major concern?