Two deuterons undergo nuclear fusion to form a Helium nucleus. Energy released in this process is : (given binding energy per nucleon for deuteron=1.1 MeV and for helium=7.0 MeV)

²₁H + ²₁H → ⁴₂He + Energy
Mass of deuterium = 2.013550
Mass of He = 4.002602
The energy released in the process is :
ΔE = 4.002602 × 7MeV − 2 × 2.01355 × 1.1MeV
ΔE = 28.018214 MeV − 4.42971 MeV
ΔE = 23.588504 MeV ≈ 23.6 MeV