Millstone Power Station: Nuclear Fission
HS-PS1-8 & HS-ESS3-2 Case Study
Explore the massive energy released by Uranium-235 fission and evaluate the cost-benefit ratio of generating carbon-free electricity versus storing long-term nuclear waste.
Context: Waterford, CT
The Millstone Nuclear Power Station is the only operational nuclear power plant in Connecticut. It generates over 40% of the state's electricity.
Unlike fossil fuel plants (coal, natural gas) that burn chemical bonds, Millstone relies on Nuclear Fission. It uses slow-moving neutrons to split heavy Uranium-235 atoms, releasing immense amounts of heat to boil water and turn turbines.
Nuclear Fission of U-235
How Millstone Generates Heat
A slow-moving neutron strikes a fissile Uranium-235 nucleus in the reactor core. It temporarily absorbs the neutron, becoming highly unstable Uranium-236. Almost instantly, it violently splits into two lighter radioactive nuclei (such as Barium-144 and Krypton-89) and releases 3 fast neutrons.
This splitting releases a massive burst of energy due to a "mass defect" (a tiny fraction of mass is converted directly to energy via E=mc²). The 3 ejected neutrons can go on to strike other U-235 atoms, creating a controlled chain reaction.
Nuclear Fission vs. Chemical Combustion
To understand why Millstone is so powerful, we must compare the energy released by splitting a nucleus to the energy released by breaking/forming electron bonds in a chemical reaction (like burning coal).
Chemical Reaction (Burning Carbon)
~4 eV
Energy per atom
Nuclear Reaction (U-235 Fission)
~200,000,000 eV
(200 MeV) Energy per atom
Evaluating Energy Resources
Engineers and policymakers must perform a cost-benefit analysis when deciding how to generate grid electricity.
The Benefits (Pros)
- Zero Carbon Emissions: Unlike coal or natural gas, the fission process does not produce CO₂, making it crucial for mitigating climate change.
- High Energy Density: Due to the 50,000,000x multiplier, a tiny amount of Uranium fuel powers millions of homes.
- Reliability: It provides consistent "baseload" power 24/7, regardless of weather (unlike solar or wind).
The Costs & Risks (Cons)
- Radioactive Waste: The fission products (like Ba-144, Kr-89) are highly radioactive "spent fuel" that remains hazardous for over 10,000 years.
- Storage Geopolitics: There is no permanent national repository in the US. Spent fuel sits in dry casks on-site at Millstone, requiring long-term security.
- High Capital Cost: Building new, safe nuclear reactors is extremely expensive and takes decades.