Emergency source containers: what do the regulations say?
12/02/2015
Mark Brooks of Gilligan Engineering takes a look at a few of the issues relating to the Ionising Radiation Regulations regarding emergency equipment, in particular emergency containers, including the clarity of the regulations, equipment types, transportation and best practice…Why do you need an emergency container?
The Ionising Radiation Regulations 1999 (IRR99) require that an emergency container is on hand to facilitate the safe retrieval of a source in the event of an incident involving ionising radiation. The regulations state that contingency plans must be in place by the establishment in consultation with the Radiation Protection Adviser (RPA) to resolve any foreseeable emergency. The regulations give a list of essential special equipment that must be available during an emergency, and an emergency storage container (EC) is one of these items.
The regulations are clear, or are they?
The regulations are clear: each site must have an emergency container for radioactive sources used in industrial radiography. However, where they are unclear is how many emergency containers you need. You must have access to an emergency container, but does this mean it has to be somewhere on the site where you can go and collect it if an emergency occurs? Another interpretation is that an EC must be part of your radiography kit and you must have it right by you when you are conducting radiography. The number of ECs owned by a company varies from one company to the next, with some having just one for many sources in use to others who will have one EC for each source in use on site. It is often hard to tell how many sources a company may have the need for; sometimes extra sources are bought in, in order to keep up with the workload, and therefore it is hard to predict how many emergency containers are required. In circumstances similar to these it is important to ensure the essential emergency kit (as stated in Section 33 of JSP 392: Radiation Safety Handbook) follows the number of radiography teams, sources and containers you have in use.
Equipment type
There are many brands of equipment in use in gamma radiography and each has a different model of source pigtail. The emergency container used should be able to be loaded with this pigtail, allowing the radioactive isotope to be stored in the correct location. The other important property of an EC is the shielding used. This is commonly lead; however, it could be depleted uranium. The size and shape of this shielding could vary and, most importantly, this will affect the amount it attenuates the radiation by. There are no set regulations on how much the radiation should be attenuated to; however, typically a value of 2 mSv/hr on the surface of the container is used.
Transportation
If a source disconnect does occur, how the source would be transported to a safer place must be considered. In most cases, the recovered source would need to be transferred to an appropriate transport container, adding complications in a retrieval situation and increasing the level of exposure. Using an appropriate EC with a transport certificate ensures a damaged or suspect source can be transported off-site for inspection at an appropriate location, without the need to transfer the suspect or damaged source between containers.
Best practice
Best practice is based on each team of radiographers having access to an emergency container in case of a source disconnect, either right next to the radiography projector or in the van a short distance away. Having an emergency container very close to the radiography team ensures that if an incident were to occur, and there is no way of knowing when this would be, the radiation exposure as a result of the incident can be kept to a minimum. To implement this, however, can be very expensive. To meet best practice, sites that currently operate with several sources but only have one emergency container may need to re-think the number of emergency containers they have.
The other side, cost!
Working to best practice and creating the safest possible environment to carry out gamma radiography can come at a high cost. In today’s financial environment, companies are looking at controlling costs while maintaining the highest levels of safety and sometimes these two aims don’t go hand in hand. As with many items of kit used in gamma radiography, there is an initial purchase cost and an annual service cost. An EC is an essential piece of kit helping to keep radiographers and others working nearby safe. To comply with IRR99, there is a reasonably practical test that can be applied. Your RPA should be able to help you conclude what is appropriate and safe for the number of ECs you have and use.
A safer way
A safer method would be to use an emergency container that is Type A certified, such as Gilligan Engineering’s EC2, EC3 or EC4. This allows the EC to be transported when loaded and taken to a safer environment. Not all emergency containers are classed as Type A packages, so this should be an important consideration when making a purchase. “An important factor for us was to create an emergency container that can help minimise the radiation dose received in a potentially dangerous situation, that’s why our EC2, EC3 and EC4 are Type A certified, so that radiographers don’t have to increase their radiation exposure or risk something else going wrong through having to transfer a suspect source to a suitable transport container,” said Chris Cole, Director of Gilligan Engineering and designer of the EC range.
More information on emergency containers and the EC range is available from Gilligan Engineering, tel: 01661 836886; email: sales@gilligan-engineering.co.uk
www.gilligan-engineering.co.uk
