1. Radioactive Substances - an environmental compliance definition

Source: Ionactive Resource

Prelim

In creating this guidance two things come to mind immediately.

  1. How simple the definition is in the the UK Ionising Radiations Regulations 2017 (IRR17) which states 'means any substance which contains one or more radionuclides whose activity cannot be disregarded for the purposes of radiation protection'.
  2. When determining if a radioactive substance exists, it does exist unless the substance can be excluded from the remit of the environmental legislation (as we shall explore shortly).

What we are looking at is a 'technical' exclusion (exemption, out-of-scope etc), since if a substance is not radioactive for the purposes of environmental compliance in the UK, it does not mean that the substance is free from radioactivity.

A classic case is the radioactive mineral specimen containing naturally occurring radioactive material (NORM). For the purposes of the environmental legislation (specifically radioactive related), you do not need a permit (or equivalent) to keep or use that specimen, display it or store it. It is 'not radioactive' for the purposes of regulation. If the specimen becomes surplus to requirements it is not radioactive waste and there is no regulation over its accumulation or disposal. It is not radioactive waste. However keep in mind the following:

  • Many NORM specimens meeting the above definition may have several 100 micro Sv/h beta / on contact and measurable 10's of cm away. Can they be disregarded for the purposes of radiation protection?
  • Could such a high dose rate specimen be put in normal trade waste? What it be ALARP?
  • There may be other non-radiation related reasons it should not be disposed of to general waste (i.e. other chemical properties, heavy metal content or similar).
  • A significant store of NORM specimens (we know of whole rooms of NORM specimens), may have a Radon build up issue exceeding 300 Bq/m3 (this might then invoke IRR17).

In the guidance which follows we will generally use the guidance in England and Wales, made under EPR2016 (since Ionactive is based in the England). However, we will point you in the right direction for each of the devolved administrations of the UK.

As we will discuss later, in defining radioactive substances we are really saying : Are they out-of-scope (not radioactive), exempt (radioactive but can be held under an exemption provision so not regulated), or radioactive substances (in which case they are formally regulated). Complying with exempted radioactive substances is dealt with in Part D - Exemption and Out of Scope. We encourage you to read Part D carefully as there are a few differences in how this is applied across all administrations. For example, you can hold a 555 MBq electrodeposited Ni-63 sealed source (e.g. in a gas chromatograph unit) in England and Wales under exemption. In Scotland you need to declare to SEPA that you hold such sources, and comply with their 'Binding Rules'. You may want to head back to Part A - 3. Permits, registrations and authorisations for radioactive substances and waste in the UK for a reminder of the regulation applied in each devolved administration.

Reference documents

The document we will be working from is this : Scope of and exemptions from the radioactive substances legislation in England, Wales and Northern Ireland (this will open in a new window, it is a massive document!) At this stage we are not interested in exemption conditions, that will be found in Part D (Exemption & Out-of-scope) of this guidance.

Also of relevance is this document: Guidance on radioactive substances activities in Scotland that are out of scope of the Environmental Authorisations (Scotland) Regulations 2018 (EASR) (this will also open in a new window).

For the most part the actual figures presented are the same in both documents (they are derived from EU and IAEA standards). Some of the terminology is slightly different, and as already pointed out for Ni-63 sources above, Scotland treats their regulation slightly differently. In the resource which follows, references relate to the first link above (England, Wales & Northern Ireland). Any references to the Scottish publication will be be follows by [Scotland].

So - let us dig in! There are three sub-categories to consider which define radioactive substances.

NORM industrial activities

Here is the criteria, with references (tables feature in the first link above).

  • NORM industrial activities listed in Table 2.1 A, and at least one or more of the following apply
  • 'Column 2' Bq/g limits exceeded for solid or ‘relevant liquid’ (Table 2.2)
  • 'Column 3' Bq/l limits exceeded for aqueous liquid (Table 2.2)
  • 'Column 4' Bq/m3 limits exceeded for gaseous (Table 2.2).

Let us look at this in a little more detail.

For NORM industrial activities, we have from table 2.1A the following:

  • Production and use of thorium, or thorium compounds, and the production of products where thorium is deliberately added
  • Production and use of uranium or uranium compounds, and the production of products where uranium is deliberately added

Now let us look at Table 2.2 (open the above link and go to page 22). Let us look at the data for Po-210. The data is as follows, assuming that Po-210 fits into one of the two industries mentioned above (it does - Zircon sand is used in the ceramic industry and contains U-238 and Th-232 series radionuclides that will yield Po-210 via Pb-210 decay).

  • Solid or relevant liquid - 5 Bq/g Po-210
  • Aqueous liquid - 0.1 Bq/l
  • Gaseous 0.01 Bq/m3

In the circumstances noted above, if the criteria exceeds the levels noted, then Po-210 is a radioactive substance.

Right, on to the next one.

NORM used for its radioactive, fertile or fissile properties

For this definition the practice involves using a NORM material specifically because of its radioactive, fertile or fissile properties.

For this definition, radioactive substances are those that appear in Table 2.3 (see above link) where they are solid (or a relevant liquid) and the Bq/g concentration level is exceeded. Using Po-210 again as our example, radioactive material will be present where the activity concentration is > 0.01 Bq/g. Note the difference in values between the first and second definitions (5 Bq/g vs. 0.01 Bq/g). It is important to ensure you understand the nature of the practice in order to define radioactive material correctly - this is where you may wish to consult the Ionactive Radioactive Waste Adviser (RWA).

Artificial radionuclides

For this category, a practice where substances containing radioactive materials appear in Table 2.3, and where they are solid (or a relevant liquids) and the Bq/g concentration level is exceeded. This time let us use P-32 as used in many universities. You will have a radioactive substances where 1000 Bq/g is exceeded.

Aside - It is interesting to compare in this category Po-210 (our previous example) and P-32. We have 0.01 Bq/g [Po-210] compared with 1000 Bq/g [P-32]. This would suggest a considerable difference between the radiological significance of Po-210 as compared to P-32. Po-210 is an alpha emitter whereas P-32 is a high energy beta emitter. [If you want to know more you could consider our online RPS training course where these matters are considered in detail].

Any difference with the Scottish document?

No! In terms of the three definitions of radioactive substances given above, there are no differences.

The table references are slightly different but the actual values are the same. Table 2 and Table 3 are used in the Scottish guidance.

Ionactive comment - why not just do one document for the whole of the UK?

Anything else that excludes a material from being a radioactive substances?

Despite the above definitions, there are still circumstances where a material is NOT a radioactive substance. This means they are 'out-of-scope' and not considered further under the environmental legislation.

  • Radionuclides, where the half life is <100 seconds.
  • Where the radioactivity is solely related to artificial background radiation.
  • Where the material is contaminated with radionuclides and they remains on the premises where they were
    contaminated.
  • Where It has been previously lawfully disposed of as a waste, or is contaminated as a result of such a disposal.
  • Where the material has arisen from the remediation of land contaminated by Ra-226 prior to 13 May 2000 and the values are less than those given in Table 2.2 (for the English et al guidance, Scotland is the same).

As noted before, they 'may' still be regulated under the Ionising Radiations Regulations 2017 (Ionactive guidance). If in doubt contact the Ionactive Radiation Protection Adviser (RPA).

Reality is merely an illusion, albeit a very persistent one

– Albert Einstein -