Zr
Zirconium
Z = 40 · Transition Metal · 91.2 u
Nuclear Engineering Significance
Standard fuel cladding material (as Zircaloy alloys). Chosen for its very low thermal neutron absorption cross-section (σ_a = 0.185 b) combined with adequate mechanical properties at reactor operating temperatures. Zr-water reaction at high temperatures produces hydrogen — a key concern in severe accident analysis.
Basic properties
- Atomic number (Z)
- 40
- Standard atomic mass
- 91.2 u
- Category
- Transition Metal
Isotopes & cross-section data
| Isotope | Mass (A) | Half-life | ZAID | Libraries |
|---|---|---|---|---|
| Zr-90 | 90 | Stable | .80c.71c.70c | |
| Zr-91 | 91 | Stable | .80c.71c.70c | |
| Zr-92 | 92 | Stable | .80c.71c.70c | |
| Zr-93 | 93 | 1.53e6 y | .80c.71c | |
| Zr-94 | 94 | Stable | .80c.71c.70c | |
| Zr-95 | 95 | 64.02 d | .80c.71c | |
| Zr-96 | 96 | Stable | .80c.71c.70c |