What are the risks to your business from radiation?

What are the risks to your business from radiation?
Failing to detect radiation contamination in scrap will cost you time and money. Here we explain the risks and what you can do to make sure you protect your people and your profits.

What is radioactive contaminated scrap? Where is it from?

There have been many incidents worldwide where radioactive materials have become incorporated into the scrap metal chain. The radioactive material tends to originate from the following sources:

  • 'Orphan' radioactive sources – these are radioactive sources that are out of regulatory control and typically come from redundant industrial equipment such as gauges used for process control or redundant radioactive sources from medical applications.
  • Naturally occurring radioactive material (or NORM) or low specific activity (LSA) scale - NORM typically contains uranium-238 and thorium-232 and comes from zircon sands or refractory materials. LSA scale contains radium-226 and scrap metal or items of plant such as pipes can be contaminated with significant quantities. In addition, natural thorium, which contains radioactive thorium-232, is used in various alloys for specialist applications (eg aerospace) and welding rods. Scrap metal containing enhanced levels of these naturally occurring radionuclides can find its way into the metal supply chain.
  • Nuclear material - material originating from the nuclear fuel cycle has occasionally been found in the scrap supply chain. Whilst most countries with a nuclear industry have very rigorous controls over the release of potentially contaminated scrap metal for recycling, lack of controls in some countries has resulted in high value scrap such as stainless steel or copper being contaminated with radioactive material.
  • Steel – there have been incidents more recently when imported steel has contained radioactive material as a result of an orphan source being melted with the steel during the production process.

What are the hazards and risks?

Radionuclides (an unstable form of a chemical element that can emit nuclear radiation) give off a range of ionising radiations which can cause damage to cells and increase the risk of developing cancer. The nature of the hazard depends upon many factors such as:

  •     the particular radionuclide present;
  •     how much is present (measured in becquerel (Bq) the unit of radioactivity or ‘source strength’);
  •     the type of ionising radiation it gives off when it decays and how that radiation interacts with the human body; and
  •     the distance from the source.

Where will the hazards arise in the workplace?

Sealed radioactive sources are usually housed in an outer casing or container which acts as a shield to the radiation. 'Orphan' sealed sources from redundant industrial plant can present an immediate hazard in the scrap yard if this shielding is missing or damaged on initial receipt. They may present little risk if the container is properly closed and locked.

When scrap is processed and sorted by fragmenting, shearing, milling, cutting, etc, there is a potential for loss of shielding and subsequent significant exposure of employees to external radiation. Loose radioactive material can then contaminate large areas of processing plant including scrap yards with significant potential for exposure of operatives to internal radiation by ingestion or inhalation. If a source is ruptured during smelting, the linings of furnaces, slag- handling facilities, bag houses and the actual product can all become contaminated. Shutdown and decontamination of plant can be very expensive and time consuming.

What can be done to reduce the risk? Use of monitoring, alarms etc.

Ionising radiation cannot be detected by human senses, but loads entering the scrap chain can easily be scanned for external gamma radiation by passing vehicles through a portal monitoring system, often installed at the weigh bridge.  Upon detection of radiation, an alarm will sound to alert the operator. More sophisticated systems are available which will also indicate the likely position of the source(s) within the load as well as an indication of the radionuclides present in the load.

It is normal practice to monitor product on both entry into and exit from the premises, since monitoring is not guaranteed to detect the presence of a very well shielded radioactive source or radioactive contamination buried deep inside the load, where the load itself can effectively shield the source from detection.

Let us help

MMH Recycling Systems are experts in systems to detect radiation contamination in scrap metal and can help you protect your business. Find out more about RadComm radiation detection systems or contact us for more information.