Incidents happen, are you prepared?
This article looks at some of the key issues surrounding a source disconnect, how can they happen and most importantly, what can be done to prevent them.
An example incident:
A night time site radiographer working in a power station slipped on a stairway whilst carrying a source container in one hand whilst also carrying a box of loose items in the other. The container housed a relatively low, but still potentially dangerous Ir192 (1.8Ci) source. The container was still connected to the guide tubes and had the locking key left in lock. A second radiographer removed the guide tubes and placed them in the box with the loose items. Others came to the scene to assist although no one was wearing a personal alarm dosimeters other than two passive personal alarms. When a third helper came to the scene, his personal alarm dosimeter sounded. When they used radiation monitors it was discovered that the source had left the container and was in the box of loose items fully unshielded. All the radiographers had been exposed to the unshielded source and received an unneccessary dose of radiation.
Why did this happen?
Source containers should never be transported without the source being home and locked. This is standard good working practice and shown in the operating manual of every type of equipment. Most importantly a complete radiation survey of the work area and container was not conducted otherwise the free source would have been found.
The source leaving the container was due to a damaged component on the container that had not been rectified due to the company not having the equipment serviced in a timely manner. A properly serviced container is a legal requirement to comply with the transport and IRR 99 regulations the lack of maintenance in this instance gave rise to the source disconnect.
Steps to prevention:
• Operation manuals stipulate the equipment is serviced annually and if required more frequently. It is advisable a service of the container is carried out on each source load.
• Examine the container daily. If there are any issues, they will be noticed and the equipment can be quarentined.
• One of the most common reasons for unneccessary exposure is lack of communication between radiographers on different shifts. For example, a container dropped or damaged on one shift may not be noticed by the following shift when an incident could occur.
• By examining the container at the start of each shift before work it will reduce the risk of a source disconnect.
• Many radiographers are given the containers and other essential equipment to carry out work without having full training. Without full training on each piece of kit, essential procedures may be missed introducing a serious safety risk.
• Regulations state that you must have emergency storage for a source. If a source were to disconnect it would need to be stored somewhere safe that shields the radiation to a safe level. Any delay in acessing an emergency container will increase the risk of receiving an unneccessary exposure.
How can we help?
At Gilligan Engineering Services we service each container when they are due a source reload, this ensures that servicing isn’t just conducted annually but a high activity new source is loaded into a container that is newly serviced. We can offer to work alongside you to help ensure your equipment is working correctly and more than that your equipment and setup is safe, efficient and providing the best radiographs possible. We will visit your sites with the radiographers to offer training, advice and solutions to issues that radiographers deal with on a daily basis and bring with us equipment and accessories for you to try.
The IRR99 require that an Emergency Container (EC) is on hand to facilitate the safe retrieval of a source in the event of an incident in particular a source disconnect. Our EC’s are small compact and light and have been designed, built and tested to these requirements. It can be supplied for use with Viking, Tech Ops or Gammamat source assemblies. Our EC’s also have a Type A certificate allowing it to be transported when loading, avoiding further complications in a retrieval situation.For more information on our EC's please click here.