Neptunium

Nuclear Engineering Significance

Minor actinide produced primarily via U-235(n,γ)→U-236(n,γ)→U-237→(β⁻)→Np-237, and to a lesser extent U-238(n,2n)→U-237→Np-237. Np-237 (t₁/₂ = 2.14 × 10⁶ y) is a major long-term contributor to spent fuel radiotoxicity and a proliferation concern. Transmutation of Np-237 is a key goal in advanced fuel cycle research.

Atomic number (Z)

93

Standard atomic mass

237.0 u

Category

Actinide