Environmental guidance for your business in Northern Ireland & Scotland

What is a radioactive substance

What is a radioactive substance?

Radioactive substances include radioactive material and radioactive waste. Different legal controls apply to handling radioactive material and dealing with radioactive waste.

Materials that have very low levels of radioactivity, some naturally occurring radioactive materials (NORM), some wastes that contain very low levels of radioactivity and materials with a very short half-life pose such a low risk to human health that they are out of scope of the regulations. This means that no controls from the radioactive substances regulations apply to their use or their disposal.

Materials with higher levels of radioactivity, but which still pose a very low risk to human health or the environment, are exempt from the regulations. This means they can be used and disposed of without informing the regulators, so long as certain conditions are met.

If you keep or use radioactive materials, accumulate and dispose of radioactive wastes and carry out activities that are not out of scope or exempt, then you will require:

  • a certificate of registration, for keeping and using radioactive materials,
  • a certificate of authorisation for the accumulation or disposal of radioactive wastes.

Radioactive material

Radioactive material includes substances or articles that are radioactive, or have become radioactive through non-natural processes, for example at a nuclear reactor.

Radioactive materials are used by many organisations. For example, hospitals, research organisations, radiographers and process industries use radioactive materials for:

  • diagnosing and treating disease
  • controlling industrial processes
  • preventing static electricity
  • industrial radiography
  • scientific research.

Different types of radioactive material, including open and sealed radioactive sources, are used for different activities.

Open radioactive sources are radioactive materials that you can easily divide, disperse or dilute. They can be in a liquid, gaseous or sometimes solid form. Open sources include radioactive laboratory chemicals and radiopharmaceuticals.

Open radioactive sources can potentially contaminate other material through leakage or leaching. You must store all open radioactive sources securely.

Sealed radioactive sources have a structure which prevents radioactive material from leaking during normal use. If you use sealed sources incorrectly you could cause radioactive contamination.

Sealed radioactive sources used to be called 'closed' sources. They are categorised according to their hazard or risk as:

  • high activity sealed sources (HASS)
  • sources of similar potential hazard to HASS
  • low hazard or low risk sealed sources.

A sealed source may take the form of a welded steel capsule, or a homogenous, laminated, electrodeposited or foil source.

HASS present a greater hazard to the environment and human health than other sealed sources. HASS may include sterilisation sources, hospital radiotherapy sources, industrial radiography sources, density and moisture gauges and some industrial process control gauges.

Mobile radioactive apparatus

Mobile radioactive apparatus includes equipment, appliances or other things that are portable and classed as radioactive material. They may be used for:

  • testing, measuring or investigation
  • releasing radioactive material into the environment or introducing it into organisms.

Mobile radioactive apparatus may contain sealed or open radioactive sources.

You must have a certificate of registration if you use or keep mobile radioactive apparatus, unless you are covered by an exemption.

Radioactive waste that is exempt

An exemption only applies if the total amount of radioactive material on your site is below a certain threshold. This total includes the materials that you keep and use as well as the wastes that you accumulate on site for disposal.

The waste you produce will be classed as radioactive waste only if it has certain properties. This depends on:

  • the activities that produce the waste
  • the presence of naturally occurring radionuclides that you have used for their radioactive properties
  • the presence of artificial radionuclides
  • the concentration of the above radionuclides in the waste, with regard to threshold values set out in the regulations.

Details of these conditions and the threshold values can be found in section 3 of the Government guidance document:

GOV.UK: Guidance on the scope and exemptions from radioactive substances regulations in the UK

If the waste you produce is radioactive waste and it is covered by an exemption, there are conditions that apply to the disposal of the waste.

Radioactive waste that is not exempt

If you keep and use radioactive materials, and accumulate radioactive waste, and:

  • the total amount of radioactivity is above the threshold required for an exemption,
  • or the concentration of radionuclides in the materials you use is above the threshold values required for an exemption,

then you will need a certificate of authorisation from your environmental regulator.

Further information

DAERA Northern Ireland: Radioactive substances

Scottish Environment Protection Agency (SEPA): Radioactive substances

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