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Calcimator

Nuclear Fuel Burnup Calculator

Calculate energy extracted from nuclear fuel assemblies by burnup level in MWd/MTU.

Inputs

MWd/MTU
%
lb
MWt

Results

Total Core Energy

95,882 GWh(t)

Estimated Cycle Length

1,175 days

Energy per Assembly20,700 MWd
Energy per Assembly496.8 GWh
Electricity Generated31,641 GWh(e)
U-235 Consumed per Assembly20,700 g
Residual Enrichment (est.)0%
Initial Decay Heat at Shutdown204 MW
Pu Buildup39,951
Relative Activity1
Homes Per Year3,013,446.86
How to Use This Calculator
  1. Enter Target Burnup, Initial Enrichment, and Assembly Mass (UO₂).
  2. Set Reactor Thermal Power and Number of Assemblies.
  3. Review Total Core Energy (GWh(t)) and Estimated Cycle Length (days).
  4. Use Energy per Assembly (MWd) and Energy per Assembly (GWh) to inform your decision.
  5. Use the chart to visualize the results and explore different scenarios by adjusting inputs.

How the result changes with Target Burnup

Target BurnupTotal Core EnergyEstimated Cycle Length
10,90023,225 GWh(t)285 days
35,65075,960 GWh(t)931 days
65,350139,243 GWh(t)1,706 days
90,100191,978 GWh(t)2,353 days

What each input means

Target Burnup
Discharge burnup target in megawatt-days per metric ton of uranium. Typical PWR: 40,000–60,000.
Initial Enrichment
Initial U-235 enrichment in weight percent. Typical PWR: 3.5–5.0%.
Assembly Mass (UO₂)
Mass of uranium (as UO₂) per fuel assembly in kg. PWR: ~460 kg, BWR: ~175 kg.
Reactor Thermal Power
Total reactor thermal power in MW. Typical 1 GWe PWR: ~3400 MWt.
Number of Assemblies
Number of fuel assemblies in the core. Typical PWR: 157–241, BWR: 500–800.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Target Burnup = 45000, Initial Enrichment = 4.5, Assembly Mass (UO₂) = 460, Reactor Thermal Power = 3400 = 5 input(s) provided
  2. Calculate Total Core Energy
    Total Core Energy
    95882 = 95882
  3. Calculate Estimated Cycle Length
    Estimated Cycle Length = cl
    1175 = 1175
  4. Calculate Energy per Assembly
    Energy per Assembly
    20700 = 20700
  5. Calculate Energy per Assembly
    Energy per Assembly
    496.8 = 496.8

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