Ionising Radiations Regulations 2017 (IRR17) Guidance - Part 6 - Arrangements for the control of radioactive substances, articles and equipment

Apart from the critical examination of radiation generators, most of part 6 has certain parallels with UK environmental legislation for the keeping and use of radioactive materials (both sealed and unsealed). The various UK regulators (e.g. HSE and Environment Agency in England) have agreed there is no need for two separate record keeping systems - one system can be designed to meet all requirements.

  • IRR17 (28) - Sealed Sources & articles containing or embodying radioactive substances
  • IRR17 (29) - Accounting for Radioactive Material
  • IRR17 (30) - Keeping and Moving of Radioactive Substances
  • IRR17 (31) - Notification of certain occurrences
  • IRR17 (32) - Duties of manufactures etc of articles for use with work with ionising radiation.
  • IRR17 (34) - Misuse of or interference with sources of ionising radiation

IRR17 (28) - Sealed Sources & articles containing or embodying radioactive substances

Where a radioactive substance is used, it shall if possible be in the form of a sealed source (i.e. not dispersible). The design of any source must be so as to prevent leakage, and:

  • in the case of a sealed source, prevent leakage so far as is practicable; or
  • in the case of any unsealed source, prevent leakage so far as is reasonably practicable

Where it is appropriate, the employer must ensure that suitable tests are made at suitable intervals to detect any leakage. Typically, this test (‘leak test’) will be in the form of a ‘wipe’ made to the standard required by ISO 9978.

A record of these tests must be kept for 2 years after the source is disposed of, or until a further record is made of a subsequent test.

Where testing is appropriate under normal operating conditions the interval between tests should not be more than 2 years.

The Radiation Protection Adviser will normally be consulted by the RPS or employee to assist in determining what is ‘appropriate’. For example, it may be appropriate in certain circumstances to extend the testing interval of certain fixed gauges to meet plant maintenance schedules (which may have plant shut down every 3 years).

For older sealed sources outside their recommended working life, and normally at the request of the UK environmental regulators or on the advice of the RPA, the leak test frequency may be increased to perhaps once every 12 months. Unless otherwise known, the recommended working life of a sealed source should be assumed 15 years.

Note that sources outside their recommended working life will lose their special form status. This does not mean that the source is about to fail integrity, but it could have impact on:

  • The Radiation (Emergency Preparedness and Public Information) Regulations 2019 (REPPIR does not apply to special form sources. If special form status is lapsed the employer 'might' need to undertake an assessment to show that the sealed source is not dispersible under all identified hazard conditions so that the source remains outside of REPPIR requirements).
  • The transport of the source. For example, certain sources that can be carried in a Type A transport container may need to be carried in a Type B container if special form status has lapsed.

IRR17 (29) - Accounting for Radioactive Material

An employer must keep records of the quantity and location of radioactive substances and sources. They must be kept for at least 2 years after they were made and for at least 2 years after disposal of the radioactive material.

The records should be in a format that will allow loss of any significant quantity of radioactive material to be readily identified. Frequency of checking will depend on likely movements of material and how they are used (e.g. dilutions in laboratories and similar).

The IRR17 ACoP states that for static sources attached to machines, the interval between checks may be up to 1 month and for portable sources checks should be made daily.

IRR17 ACoP paragraph 579 is useful . This paragraph has the legal status of ‘guidance’ and therefore following it can be assumed to be acceptable, if not best practice. It states that employers who are subject to the requirements of the environmental permitting legislation may use a single system of accounting which satisfies both sets of legal requirements. For the UK the relevant legislation is as follows:

Many employers utilise the RPS to ensure that accounting under IRR17 and the environmental legislation is compliant. This is one reason an RPS will be appointed regardless of the legal need to do so (i.e. where these is no legal need to designate an area as Supervised or Controlled).

It should be noted that none of three sets of legislation above define the RPS (only IRR17 does this). Therefore, whilst the RPS may take on a role assisting with the compliance of radioactive substances environmental legislation, it is NOT within the specific remit of the RPS (other than for compliance with IRR17 which may not go as far as the environmental legislation). Modern legislation like EPR2016 specifies the requirement for competent persons - this could be the RPS if suitably experienced.

IRR17 (30) - Keeping and Moving of Radioactive Substances

Sources must be kept in a suitable receptacle and in a suitable store. Sources being moved as opposed to transported (i.e. within a site) must be in a suitable receptacle.

As noted for IRR17 (Regulation 29) a common system can be employed which meets the needs of IRR17 and the relevant environmental legislation. However, IRR17 Regulation 30 does provide some specific guidance on a suitable receptacle and suitable store.

Suitable receptacle

(a) radiation shielding – it is advisable that the surface dose rate never exceeds 2 mSv / h and usually it should be much less

(b) the ability to withstand damage from normal use and foreseeable misuse or accident

(c) fire resistance

(d) prevention of unauthorised access, exposure or dispersal

Special considerations are also required where:

(a) the radioactive substance is corrosive, self-heating or pyrophoric

(b) there could be pressure build-up inside the receptacle

(c) the storage environment itself is corrosive

Pressure build-up. This can occur in aged alpha emitting sources such as encapsulated Am-241. The encapsulation means that alpha particles never escape (this source is either designed for its 60 keV gamma radiation, or is combined with beryllium to form a neutron AmBe source). As the alpha decay proceeds over many years there is pressurisation of the capsule due to helium production which is the end point of alpha particle interaction. The design of the capsule takes pressurisation into account, but an aged source in a fire could result in containment failure in a worse case scenario.

Suitable store

(a) protection from the weather;

(b) resistance to fire sufficient to minimise dispersal and loss of shielding, taking into account combustible materials in the vicinity and the likely temperatures that would be reached

(c) shielding to achieve the lowest dose rate that is reasonably practicable outside the store. Where non-classified persons may approach the outside of the store, it is suggested that the dose rate does not exceed 2.5 μSv per hour. A further goal would be to reduce this to < 1 μSv per hour and therefore approach background levels.

(d) ventilation for both radioactive and non-radioactive substances that have accumulated as both may be harmful. Ventilation should also be provided for a radioactive substance that has been spilt or accidentally dispersed. Ventilation may also be required for substances that emit radon gas.

(e) physical security so that access is only possible to people permitted by the employer. There may be interaction between this requirement and that of the CTSA (counter terrorism security adviser) who will work and advise on behalf of the UK environmental agencies.

IRR17 ACoP paragraph 594 states ‘… a sign prominently displayed on the outside of the store (preferably on the door) will warn people that the store may contain radioactive substances. Such signs must conform to the Health and Safety (Safety Signs and Signals) Regulations 1996…’ It is the experience of Ionactive that the size and location of such signs can cause strong debate between the HSE and Environmental regulators (the environmental regulators and their security advisers do not like advertising the location of radioactive material).

IRR17 (31) - Notification of certain occurrences

Where the quantity of radioactive material controlled by an employer exceeds the value given in Schedule 7 (column 5, part 1) of IRR17, they must notify the HSE if there has been a release (i.e. not being allowed under environmental legislation), or spillage in excess of the quantity listed in that Schedule.

Typical values for notification (taken from Schedule 7) are are follows.

Notification of a spill

  • H-3 [1 TBq (Tritiated)]
  • P-32 [10 GBq]
  • Ni-63 [100 GBq]
  • Ra-226 [10 MB]
  • Tc-99m [10 TBq]
  • U-238 [10 MBq]

Notification of loss or theft

This regulation also deals with circumstances where a radioactive material is believed or known to be lost or stolen. If loss or theft has arisen (after carrying out an immediate investigation) the radiation employer needs to forthwith notify the HSE and police.

Similar notifications will also be required by the previously mentioned environmental legislation.

  • H-3 [10 GBq (Tritiated)]
  • P-32 [1 MBq]
  • Ni-63 [1 GBq]
  • Ra-226 [0.1 MBq]
  • Tc-99m [100 MBq]
  • U-238 [0.1 MBq]

Other details

Investigation reports need to be kept for at least 30 years.

This regulation links with certain requirements contained in the Reporting of Injuries, Diseases and Dangerous Occurrences Regulations 2013. This link applies to radioactive substances and any other radiation generators, specifically requiring notification to the HSE where:

  • the malfunction of a ‘radiation generator’ used for fixed / mobile industrial radiography, irradiation of food or processing of products by irradiation, causes it to fail to de-energise at the end of the intended exposure period, or
  • the malfunction of equipment used in fixed / mobile radiography causes a radioactive source to fail to return to its safe shielded position at the end of the intended exposure period.

IRR17 (32) - Duties of manufactures etc of articles for use with work with ionising radiation.

Some definitions (supplier, article, substances)

This regulation extends the provisions of the Health and Safety at Work etc. Act 1974 (HSWA). In relation to work involving ionising radiation, this regulation requires that an appropriate critical examination of equipment is undertaken after installation. This regulation applies to suppliers of material goods, i.e. ‘articles’ or radioactive substances.

The aim of this regulation is to ensure that consideration if given to radiation protection throughout the supply chain, from design, through to manufacture, during supply and at the point of installation. The RPS and Radiation Protection Adviser are likely to be involved, with the installer, during the critical examination.

For the purposes of this regulation, and its link with HSWA, a supplier can be defined as:

  • someone who supplies articles or substances by sale, lease or hire (regardless of being a principle or agent in the supply chain), and will include designers, manufactures, importers, installers and erectors etc

In addition, an article can be defined as:

  • any plant, machinery, equipment or appliance that is designed for use by persons at work, and this will also extend to any component of any article

In the above definition is should be noted that an article will include equipment that produces adventitious radiation as well as intentional radiation. An example of this might be a radar installation which produces radar waves, but where the equipment may also produce adventitious x-rays.

Substances will mean:

  • a sealed or unsealed radioactive substance, which could also include radioactive contamination

The regulation requires that radiation protection considerations are incorporated into the design and construction stages of manufacture and are not left to the end user.

Critical examinations

There is no legal requirement for the Radiation Protection Adviser (RPA) to be directly involved in any critical examination. However, it is a requirement that the RPA:

  • advises on the nature, scope and extent of the critical examination
  • gives advice on the results of any examination; ensuring that the safety features and devices designed to restrict exposure are functioning as intended
  • advises on how the results should be presented and retained

Generally it is Ionactive experience that:

  • For simple uses of ionising radiation (e.g. bench top x-ray QA unit) the installation / service engineer of the suppler will set up the equipment and carry out a critical examination.
  • For higher hazard installations (e.g. linac / HASS / irradiators) the RPA for the installer is usually involved directly in the critical examination process.

When a new piece of equipment (an article) arrives on site which emits ionising radiations (whether entirely contained or otherwise), the person installing shall:

  • where appropriate, undertake a critical examination of the way that it was erected or installed, for the purpose of ensuring in particular the safety features and warning devices operate correctly and there is sufficient protection for persons from exposure to ionising radiation
  • consult with the Radiation Protection Adviser appointed by himself, or the radiation employer (where the article is being installed), with regard to the complexity and extent of the critical examination and the results of that examination
  • provide the employer (who will use the article) with adequate information about proper use, testing and maintenance of the article (including a written record of the examination)

The RPS at the site when the equipment is being installed is very likely to be involved in the critical examination, if only to ‘supervise’ the work if it’s taking place in a designated area. Furthermore, many RPSs are also the users of the equipment and so have a personal interest in knowing that they have been installed and tested correctly.

Alternatively, for the higher hazard facility, at the point the critical examination is being carried out, the area may be under the control (so far as IRR17 is concerned) of the supplier rather than customer (until the area is handed over).

The critical examination should test the article under the most extreme conditions likely to be encountered in normal usage and check that all safety features / interlocks / signs and signals are operative. The user must be informed of the results of the test, including results of proven performance and operational limitations.

This requirement for testing applies only to those aspects of the equipment that have a bearing upon radiological protection. Where articles are supplied for use in work with ionising radiation that have wider areas of application, then unless specific contractual arrangements have been made regarding suitability, the responsibility for testing will reside with the employer who is the customer, rather than the supplier. An example of this might be a fan motor which is used as part of a ventilation system which controls the release of radioactive material into the workplace.

Particular care must be taken with larger projects involving potentially high hazard radiation sources (for example a linear accelerator in a bunker). Often there are several companies involved which maybe headed up by a project management group. The shielding design, construction, electrical installation, services, soft fit and similar may be conducted by different companies. In these cases the 'installer' may not be as clear as you might expect and should be agreed before the project starts. The installer of the linac cannot be responsible for the radiation shielding, or the external active warning lights that interface with the linac, if these features were not in their remit.

Ionactive spends many days a year undertaking critical examinations on behalf of suppliers and end users - particularly for high hazard facilities. If you need advice - please contact us.

IRR17 (34) - Misuse of or interference with sources of ionising radiation

It is an offence to intentionally or recklessly misuse, or without justification interfere with, any radioactive substance or electrical equipment for which IRR17 applies.

Whilst the RPS is not in a ‘policing role’, it is reasonable to suggest that they will be on the lookout for misuse or other similar behaviour.