Non-Destructive Shield Testing Services for Safety

Radiation shielding plays an important role in protecting staff and the public from exposure to ionising radiation. Typically, radiation shielding is installed as part of, or within, walls, windows and doors. It is therefore essential that the shielding has been constructed and installed as per the design intent. This reassurance can be achieved by undertaking Non-Destructive Shield Integrity Testing (sometimes referred to as critical examination).

What is Non-Destructive Shield Integrity Testing?

Non-Destructive Shield Testing refers to any means of establishing whether or not the required amount of shielding has been installed during construction of a facility or component that makes use of, or houses, an ionising radiation source.

Visual inspection is largely impractical and can be destructive as partial damage of walls may be required to achieve this and it could only be ascertained that shielding has been installed in those select areas sampled. Therefore, Non-Destructive Shield Testing is used to ensure that the correct amount of shielding has been installed and/or that there are no omissions or construction deficiencies present that might lead to unacceptable radiation leakage and hot-spots.

Radiographic sources used for the testing are carefully selected depending upon their emission rate, energy and the amount of shielding to undergo testing, which for example, can range from a few millimetres of lead to several metres of concrete. In some cases, operation of equipment (e.g. a LINAC) is required to establish that the installed shielding is acceptable.

Why is Non-Destructive Shield Integrity Testing Important?

Most countries have strict regulations regarding the amount of radiation dose people can legally be exposed to. For non-radiation workers, such as members of the public, these limits are low. An employer has a duty of care to its staff and the public. Part of evidencing this duty of care is demonstrating to the relevant government health and safety board that its radiation shielding provisions are adequate. Shield integrity testing in itself may also be a legal requirement, for articles that have been erected and carry radiation protection implications.

If issues with radiation shielding are identified late, corrective construction measures can be time consuming, expensive and disruptive to the employer’s operations. Therefore, implementing Non-Destructive Shield Integrity Testing methods during construction and/or pre-commissioning can minimise the risk of such measures being required.

TÜV SÜD's Services

TÜV SÜD’s Radiation Physics Team can offer a complete radiation shielding inspection service for hospitals, industrial radiography facilities or indeed, any other facility where ionising radiation may present a hazard. This can include:

• Shield Integrity Testing – experienced staff undertake physical measurements of radiation levels through shielding using calibrated and fit-for-purpose dose rate monitors and equipment.
• Radiation Protection Supervisors – staff are trained company appointed Radiation Protection Supervisors to ensure safe operation of sources and designation of appropriate access controls, barriers and signage.
• Dose Rate Calculations – radiation transport modelling using codes such as MCNP and Attila to calculate the expected dose rates during testing prior to arrival on-site.
• Remedial Shielding Design Advice – provision of shielding design advice for any required remedial action if shielding inadequacies are found.