Nuclear power plant shielding: the biological shield is provided primarily to protect which group from ionising radiation?

Introduction / Context:
In nuclear facilities, shielding design separates high-radiation regions from areas where people work. The biological shield is a dedicated, high-density barrier meant to attenuate radiation to safe levels for humans outside core and primary circuit boundaries.

Given Data / Assumptions:

• Biological shield materials typically include thick concrete and sometimes steel or other attenuators.
• The main design objective is protection of people, not equipment.
• Radiation sources include neutrons and gamma rays from the core and primary systems.

Concept / Approach:
While reactor vessels and fuel assemblies are engineered for heat and radiation environments, the biological shield specifically addresses dose limits for humans. It reduces neutron and gamma flux to regulatory limits in accessible areas. Equipment like fuel elements or turbine blades have separate design considerations; the turbine in a PWR/BWR secondary loop is not the target of the biological shield, and vessel integrity is managed by other design margins and materials, not primarily by this shield.

Step-by-Step Solution:
Identify the shield’s purpose: reduce dose to people outside high-radiation zones.Match with the correct group: operating personnel.Exclude equipment-centric options which are not the aim of a “biological” shield.

Verification / Alternative check:
Nuclear safety texts define biological shielding explicitly with reference to human radiation protection and dose limits (e.g., mSv/hr in controlled areas).

Why Other Options Are Wrong:
Fuel elements/vessel walls: engineered for radiation but not the shield’s primary protection target.None of these/Only turbine blades: incorrect scope for biological shielding.

Common Pitfalls:
Assuming any thick structure around the vessel primarily protects the hardware; the term “biological” signals the focus on human safety.

Final Answer:
Operating personnel (human workers)