Radiation shielding analysis

Radiation shielding plays an important engineered role in protecting workers and the public from exposure to ionising radiation. Radiation shielding is incorporated into the design of a facility or item (e.g. transport flask) to ensure that dose uptake does not exceed legal limits and helps demonstrate compliance with the ALARP / ALARA principle.

What is Radiation Shielding Analysis?

Radiation shielding analysis refers to the process of developing the shielding design for a facility or plant item to protect staff and the public from the potentially harmful effects of ionising radiation.

Throughout this process, design advice is provided for the layout and thickness of shield walls, windows, doors and access/egress labyrinths. Advice can also be provided regarding detailed features such as service penetrations (e.g. HVAC and electrical penetrations), door gaps, door overlaps, local and/or temporary shielding and skyshine assessment.

Radiation shielding analysis is performed throughout the project lifecycle from concept design and operations through to decommissioning and clean-up. Analysis is performed using specialist radiation transport codes and software, including MCNP, Attila, FLUKA and MicroShield, as well as the application of analytical techniques (i.e. hand calculations) when necessary.

As such, analysis relies heavily upon the underpinning input data (e.g. source type, activity and geometry), which is typically contained within a Shielding Design Basis document. Dose rate criteria, against which the shielding is designed to comply with, are typically provided within a Radiological Classification of Areas document. In parallel, dose uptake assessment should be performed to confirm that predicted doses do not exceed legal limits, ensure doses are ALARP / ALARA and to provide an opportunity to feed back into the radiation shielding analysis where areas for dose reduction are identified.

Why is Radiation Shielding Analysis Important?

Most countries have strict regulations regarding the amount of radiation dose people can legally be exposed to. Undertaking radiation shielding analysis to determine the required shielding design for a facility or plant item is essential for controlling and minimising dose to ensure that legal limits are not exceeded and that doses are ALARP / ALARA.

Consideration of the radiation shielding design early in a project and continuous refinement throughout the project’s lifecycle ensures that the necessary radiological protection requirements are addressed. Radiation shielding analysis can identify where the civil structure of a facility will need to provide the most shielding, which can help inform engineers performing civil and seismic assessments. This reduces the risk of corrective construction measures that can be time consuming, expensive and disruptive to the employer’s operations.

TÜV SÜD Services

TÜV SÜD Nuclear Technologies Division offer a complete range of Radiation Shielding Analysis services:

• Shielding Design Advice – provision of shielding design advice, including assessment of bulk shielding, shield doors, service penetrations, skyshine and optimisation of shielding provisions and plant layouts.
• Radiation Transport Codes & Software – licenced use of several radiation transport modelling using codes including MCNP, Attila, FLUKA and MicroShield. The team make use of purpose-built, multi-core servers to enable parallel processing of Monte Carlo and discrete ordinates calculations, thereby reducing calculation times and maximising throughput for detailed radiation transport problems.
• Shielding Design Basis – production of Shielding Design Basis documentation to provide a single and consistent reference for the underpinning input data for shielding design analysis.
• 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 Uptake Assessment – estimates of the dose accrued by persons due to both external and internal sources of ionising radiation.
• Compliance with Legal & Regulatory Requirements –  expert advice on legal and regulatory compliance.
  TÜV SÜD personnel can work with the client to develop a regime that will cover the client’s requirements.