Nuclear Fission Calculator

Calculate energy release, mass defect, and reaction products for nuclear fission reactions. Supports custom fission inputs.

Fission Parameters

Select fissionable material and mass to calculate energy release

kg
%
Total Energy Released
8.20 × 10<sup>13</sup>
Joules
Usable Energy
2.71 × 10<sup>13</sup>
Joules (after efficiency)
Equivalent TNT
19,598
Tons
Homes Powered
690
For 1 year

Nuclear Fission Explained

Nuclear fission is a process where a heavy atomic nucleus splits into two or more lighter nuclei, releasing a significant amount of energy. This process is the fundamental principle behind nuclear power plants and atomic weapons.

Chain Reaction: When each fission event releases neutrons that can trigger additional fission events, a self-sustaining chain reaction occurs. This is the basis for nuclear reactors and bombs.

Fission Energy Formulas
E = Δm × c²
Δm = mass defect
c = speed of light (3 × 10⁸ m/s)
Where:
E = Energy released
Δm = Mass defect (kg)
c = Speed of light (m/s)
Typical mass defect: ~0.1% of original mass
Fission Applications
Application Material Energy Release Scale
Nuclear Power Plant Uranium-235 1 GW/year Commercial
Atomic Bomb Plutonium-239 15-20 kt TNT Weapon
Research Reactor Uranium-233 1-10 MW Research
Nuclear Submarine Highly Enriched U 150-200 MW Military
Space Propulsion Plutonium-238 100-500 W Spacecraft
Fission Facts
  • Discovered by Otto Hahn and Fritz Strassmann in 1938
  • First controlled chain reaction at Chicago Pile-1 in 1942
  • 1 kg of U-235 can produce energy equivalent to 1,500 tons of coal
  • Nuclear power provides about 10% of world's electricity
  • Fission products remain radioactive for thousands of years

Nuclear fission occurs when a heavy nucleus absorbs a neutron, becoming unstable and splitting into two smaller nuclei (fission fragments), along with several neutrons and a large amount of energy.

The process follows these steps:

  1. A neutron is absorbed by a heavy nucleus (e.g., U-235)
  2. The nucleus becomes unstable and deforms
  3. The nucleus splits into two fission fragments
  4. 2-3 neutrons are released
  5. Energy is released as kinetic energy of the fragments and radiation

The energy released in fission comes from the mass defect - the difference between the mass of the original nucleus and the masses of the fission products.

According to Einstein's equation E=mc², this mass difference is converted to energy:

E = Δm × c²

Where:

  • E = energy released
  • Δm = mass defect
  • c = speed of light (3×10⁸ m/s)

For uranium-235 fission, about 0.1% of the mass is converted to energy, releasing approximately 200 MeV per fission event.

Fission products are the atomic fragments left after a nuclear fission event. They typically include:

  • Two fission fragments: Medium-mass nuclei (e.g., barium and krypton)
  • Neutrons: 2-3 neutrons per fission that can trigger further reactions
  • Gamma rays: High-energy photons
  • Beta particles: Electrons from radioactive decay
  • Neutrinos: Nearly massless particles

Fission products are typically radioactive and decay through various processes, emitting radiation over time.

A nuclear chain reaction occurs when one fission event causes an average of one or more subsequent fission events. This leads to a self-sustaining series of reactions.

There are three types of chain reactions:

  • Subcritical: Less than one neutron causes another fission (reaction dies out)
  • Critical: Exactly one neutron causes another fission (steady reaction)
  • Supercritical: More than one neutron causes another fission (exponential growth)

Nuclear reactors operate in a critical state, while nuclear weapons achieve supercriticality for explosive energy release.

Common Fission Reactions

n + ²³⁵U → ¹⁴⁰Ba + ⁹⁴Kr + 2n + 200 MeV
Energy: 200 MeV
n + ²³⁵U → ¹⁴⁴Xe + ⁹⁰Sr + 2n + 180 MeV
Energy: 180 MeV
n + ²³⁹Pu → ¹⁴⁰Ce + ⁹⁹Zr + 3n + 210 MeV
Energy: 210 MeV
n + ²³³U → ¹⁴²Ba + ⁹¹Kr + 3n + 197 MeV
Energy: 197 MeV