Ar
Argon
Z = 18 · Noble Gas · 40.0 u
Nuclear Engineering Significance
Cover gas in some sodium-cooled fast reactor designs. Ar-40 activates to Ar-41 (t₁/₂ = 1.83 h, strong gamma emitter) in air surrounding reactor systems and in gas-cooled reactor primary circuits, creating a radiological protection concern.
Basic properties
- Atomic number (Z)
- 18
- Standard atomic mass
- 40.0 u
- Category
- Noble Gas
Isotopes & cross-section data
| Isotope | Mass (A) | Half-life | ZAID | Libraries |
|---|---|---|---|---|
| Ar-36 | 36 | Stable | .80c.71c.70c | |
| Ar-38 | 38 | Stable | .80c.71c.70c | |
| Ar-40 | 40 | Stable | .80c.71c.70c |