Regulatory and Standards Framework
Core concepts
Understand the international and national framework: IAEA safety standards (Basic Safety Standards, GSR Part 3), ICRP recommendations, and national regulatory bodies. Know the categories of practices and sources (exempt, licensed), the concepts of justification, optimization, and dose limitation, and the system of notification, authorization, and inspection. Familiarize yourself with dose limits (occupational 20 mSv/y averaged over 5 years with 50 mSv in any single year; public 1 mSv/y; lens 20 mSv/y; extremities 500 mSv/y) and the principles of transport, waste, and emergency regulation. Understand records, reporting, and the role of the radiation protection officer.
Traps
Questions often confuse occupational and public limits, or misstate the averaging period for the 20 mSv limit. Another trap is treating guidance (ICRP) as legally binding; only national regulations are enforceable. Remember that dose limits apply to the sum of external and internal (committed) dose.
Worked example
A worker accumulates 18, 22, 15, 19, 21 mSv over 5 years: total 95 mSv, average 19 mSv/y - compliant with the 20 mSv/y average and no year exceeds 50 mSv. Rule of thumb: check both the 5-year average and the single-year cap.
Practical points
ICRP recommends; national regulators enforce. Limits cover combined external and committed internal dose.