B
Boron
Z = 5 · Metalloid · 10.8 u
Nuclear Engineering Significance
Primary neutron absorber in reactor control. B-10 (σ_a = 3,840 b) has a strong ¹⁰B(n,α)⁷Li reaction used in control rods (B₄C), soluble boric acid (PWR chemical shim), and shielding. Natural boron (~20% B-10) is often enriched for more effective absorption.
Basic properties
- Atomic number (Z)
- 5
- Standard atomic mass
- 10.8 u
- Category
- Metalloid
Isotopes & cross-section data
| Isotope | Mass (A) | Half-life | ZAID | Libraries |
|---|---|---|---|---|
| B-10 | 10 | Stable | .80c.71c.70c | |
| B-11 | 11 | Stable | .80c.71c.70c |