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Radiation safety deviations in industry and research

Radiation safety deviations in industry and research

An anonymised description of the radiation safety deviations is published on this page, describing the incident, the reasons for the incident, the resolution of the incident and the measures taken to prevent similar incidents. In this way, lessons can be learned from the incident and hopefully avoid similar incidents in the future. The Radiation and Nuclear Safety Authority has recently been notified of the following radiation safety deviations in the use of radiation in industry and research:

Case 1

The shield of a radiation source used in the process industry broke off and fell from a height of a few meters. There were no workstations next to the radiation source, and the shutter of the source was locked in closed position. The workers were not exposed to radiation. The supplier of the source has maintained the device and the factory has carried out a root cause analysis of the incident to ensure that nothing similar happens in the future.

Case 2

In the production facilities of an industrial radiography site, a locked tin shed was located next to the filming location. During radiography, noises began to be heard from the shed and the radiographers immediately stopped filming. Two outside workers were present in the shed and were exposed for a total of about two minutes. Both were exposed to an estimated dose of 12.25 µSv.

Case 3

A recycling metal company reported the discovery of a radiating object in a scrap lot. The radiation gate alarmed, even though the scrap batch was driven through the gate several times, so based on this, the entire load was measured with a hand-held meter. The piece was identified as depleted uranium (uranium-238) and was stored in the company's radiation source storage. No workers were exposed to radiation due to the deviation.

Case 4

When using open sources, the worker had inadvertently touched his goggles with contaminated work gloves, and contamination had thus entered the eyebrow area. The contamination was removed by rinsing. The estimated exposure time was approximately 5 to 60 minutes. The dose to a small area of skin was estimated to be 10 mSv.

Case 5

A radiopharmaceutical manufacturing site produced a drug labelled with fluorine-18. Three people participated in the production. The drug was dispensed with a dispenser into product bottles in a lead-shielded dispensing cabinet. After dispensing, the product bottles are dropped into a radiation shield in the take-out hatch on the side of the dispensing cabinet. During the drop, the sound of breaking glass was heard and the fixed dose rate meters in the production laboratory began to alarm. The cover of the radiation shield was in place, causing the falling bottle to break when it hit the cover.

Forgetting the cover was a human error. The workers received a small additional radiation exposure because of the error, calculated at 33 µSv each. As a result of the radiation safety deviation, workers were advised to take extra care whenever handling open sources.

Case 6

A recycled metal company reported a radiating object found among scrap metal, which set off alarms at several radiation gates. The entire load of scrap metal was unloaded, and a cylindrical object was identified as the radiating object by measurements with a radiation meter. The piece was identified by as depleted uranium (uranium-238) and was stored in the company's radiation source storage after the discovery. No workers were exposed to radiation because of the incident.

Case 7

Four radiation sources to be installed were in the same transport container. The installer had to handle the radiation source capsules longer than usual to be able to choose the right source to be installed, because the identification information of the sources was not clearly marked.
For the first radiation source, the attachment was not successful, the source fell back into the transport container and had to be reattached. The second source was installed without any problems, but the third one was again difficult to install. The last source was moved as planned, as the challenging points were known due to previous events. However, the installer was exposed to extra radiation due to poorly planned installation work. The effective dose resulting from the radiation safety deviation was 0.8 mSv and the equivalent dose to the hands was 5.45 mSv.

Case 8

During a cleaning day, a small piece with a radiation source label was found in a company. This source was separate from the actual measuring equipment to which it belonged. Those working on the premises did not know what it was or where it belonged.
The measuring device, which had the radiation source as an ionizer of gases, was stored years ago when an employee retired. In that situation, apparently no knowledge was passed on that such a device even existed. Nor was the measuring device found in the company's device register. The radiation source was transferred for proper disposal. No one is known to have been exposed to radiation.

Case 9

A holder of a radiation source asked STUK how they could properly dispose of the disused sealed source device. The device contained a krypton-85 source with an initial activity of 1850 MBq. STUK (Finnish radiation and nuclear safety authority) told the owner of the device that the device would have required a safety licence and instructed on how to dispose of the source.

In response to STUK's request for further clarification, the holder of the source replied that it had acquired the source in 1999. The device was decommissioned in 2011. The holder of the source was not aware of the obligation to apply for a safety license, as the seller of the equipment had never informed of this. The device was properly disposed of.

Case 10

A radiating source was found in a metal yard with a dose rate of 68.16 uSv/h measured at the surface (the background is 0.11 uSv/h). According to the contact person, it was a piece of a stainless-steel pipe. The piece of pipe had been lifted into a plastic bucket and removed from the rest of the operation. At STUK's request, the operator identified the nuclide as Radium-226 using a meter borrowed from another unit of the company. The tube was delivered to a company that handles radioactive waste.

Case 11

An industrial company was doing maintenance work inside a tank, but the shutter of the radiometric level gauge on the side of the tank was not closed despite the work permit. The sealed source in the level gauge was a cobalt-60 source with a current activity of approximately 310 MBq. Several people worked in the tank over a four-day period. The estimated radiation doses were below the record threshold.

The reason for the deviation was found to be deficiencies in the work permit system for radiation sources. In addition, the markings on the tank, including the closure of the radiation sources, were poorly visible. The operator updated the work permit system for radiation sources and renewed and checked the warning labels on the tanks.

Case 12

A piece was found in the scrap metal load of a company processing recycled metal, which triggered an alarm at the radiation measurement port. The piece was searched for in the load with the help of portable hand-held radiation detectors and taken apart. The piece was detected to contain radioactive radium-226 and it was delivered for disposal as radioactive waste.

Case 13

An employee producing radiopharmaceuticals was finishing dispensing a batch of radiopharmaceuticals and was transferring the dispensing hose to a lead-lined waste container used to age radioactive waste. During the transfer, a needle at the end of one of the hoses came loose from the needle guard and scratched the protective glove on the other hand and caused a small scratch on the base of the index finger. The employee removed the gloves and measured the skin with a contamination meter. The hand was rinsed with warm water. After rinsing, the result did not differ from the background, indicating that all the radiopharmaceutical on the skin had been washed away.