Nuclear Fission Energy Calculator Formula

Understand the math behind the nuclear fission energy calculator. Each variable explained with a worked example.

Formulas Used

Mass Difference

mass_diff = mass_reactants - mass_products

Energy Released per Fission

energy_mev = (mass_reactants - mass_products) * 931.494

Energy per Fission

energy_j = (mass_reactants - mass_products) * 931.494 * 1.602e-13

Energy per kg of Fuel

energy_per_kg = (mass_reactants - mass_products) * 931.494 * 1.602e-13 * 6.022e23 / (mass_reactants / 1000)

Variables

VariableDescriptionDefault
mass_reactantsTotal Mass of Reactants(u)236.0526
mass_productsTotal Mass of Products(u)235.8295

How It Works

Nuclear Fission Energy

Fission releases energy because the products have higher binding energy per nucleon than the parent nucleus. The energy comes from the mass difference between reactants and products.

Formula

E = delta_m × 931.494 MeV/u

A typical U-235 fission releases about 200 MeV, which is roughly 80 million times more energy per reaction than a typical chemical reaction (~2.5 eV for TNT).

Worked Example

U-236 fissions: total reactant mass 236.0526 u, total product mass 235.8295 u.

mass_reactants = 236.0526mass_products = 235.8295
  1. 01delta_m = 236.0526 - 235.8295 = 0.2231 u
  2. 02E = 0.2231 × 931.494 = 207.8 MeV
  3. 03E = 207.8 × 1.602 × 10⁻¹³ = 3.33 × 10⁻¹¹ J per fission