Radiological Classification of Areas

In many countries it is a regulatory and legal requirement to classify an area as controlled or supervised if there is the potential for significant exposure to ionising radiation. Segregation of a facility according to a convention of assigning supervised and controlled areas based on the relative radiation hazard is a process referred to as Radiological Classification of Areas, or Radiological Designation of areas.

What is Radiological Classification of Areas?

Areas of a facility are designated as controlled or supervised based upon the actual or potential radiation/contamination levels, worker occupancy requirements and levels of operational controls necessary to achieve acceptable worker doses.

Based upon its proposed function, each plant area is given a radiation and contamination classification which specifies the levels of radiation and contamination that are acceptable given the expected occupancy in that area.

Each classification level will also typically have associated with it any necessary access controls to that area, such as locked doors, barriers, signage and whether the area can only be accessed by trained staff.

The process of undertaking the Radiological Classification of Areas enables a consistent and efficient plant layout to be developed, which assists in minimising dose uptake to ensure that legal limits are not exceeded.

Why is Radiological Classification of Areas Important?

Whilst also demonstrating compliance with any regulatory and legal requirements, Radiological Classification of Areas is important for the control and minimisation of dose uptake and assists in the development of a plant layout which facilitates the radiation protection of the workforce and public. In the preliminary design phases, it can also assist with identifying where the civil structure of a facility will need to provide the most shielding. This can help inform engineers performing civil and seismic assessments.

Furthermore, Classification of Areas can also be used as a design tool to provide dose rate design criteria as part of the process of demonstrating compliance with legal dose criteria. As such, radiation exposure can be reduced by design, resulting in less reliance upon operational and administrative controls and thereby demonstrating implementation of ALARP / ALARA throughout the design process.

TÜV SÜD's Services

TÜV SÜD Nuclear Technologies Division offer a complete range of Radiological Classification of Areas services:

• Radiological Classification of Areas – development of an effective radiological classification areas scheme in order to ensure radiological protection and enable a consistent and efficient plant layout.
• Dose Rate Calculations – radiation transport modelling using codes such as MCNP and Attila to calculate dose rates.
• Shielding Design Advice – provision of shielding design advice in order to achieve dose rates that comply with the designed radiation classification of areas.
• Compliance with Legal Requirements - expert advice on legal and regulatory compliance.