Nuclear hazards and safety (introductory)
Nuclear energy · Physics
Bohr atom
Interactive 3DElectrons orbit the nucleus in shells — switch element to see H, He and Li fill their shells.
Controls
Drag the sliders or type a value — the simulation updates live.
Study notes
(a) A worker receives 0.5 mSv per week. Is this within the 20 mSv/year occupational limit? (b) A ¹³⁷Cs source reads 100 µSv/h at 1 m. Estimate the dose rate at 4 m distance (inverse square law, no shielding). Solution: (a) 0.5 × 52 = 26 mSv/year — EXCEEDS the 20 mSv/year limit; work must be reorganized (ALARA). (b) Intensity ∝ 1/r²: at 4 m, factor 1/16 → 100/16 = 6.25 µSv/h. Distance is powerful protection.