IRR17 (13) - Contingency plans

One reason for completing a risk assessment (IRR17 - Regulation 8) is to determine if a radiation accident is reasonably foreseeable. IRR17 - Regulation 2 defines a radiation accident as ‘where immediate action would be required to prevent or reduce the exposure to ionising radiation of employees or any other persons’.

Despite many definitions, ‘reasonably foreseeable’ is still open to interpretation by clients, Ionactive, and regulators - it is not defined in IRR17. A popular definition is that a reasonably foreseeable accident, which results in injury or damage (i.e. unplanned radiation exposure), should be predicted by a reasonable person with necessary skills and knowledge (i.e. an RPA). However, we point out to clients that the risk assessment and contingency plan development is a joint effort– lots of input is required from the employer to ensure nothing has been missed.

Where a radiation accident is deemed reasonably foreseeable the employer will need to prepare a contingency plan. The plan must be designed to achieve restriction of exposure (so far as is reasonably practicable). ‘Contingency plan’ applies to all users of ionising radiation where a radiation accident is reasonably foreseeable - however the plan will be proportional to the exposure risk. An x-ray machine that fails to cease x-ray production during routine use may require no more than an emergency stop being pressed, or the power supply being removed. Whereas, a spill of radioactive material in a laboratory may need a comprehensive contingency plan which requires a spill kit, trained employees using PPE, and post incident monitoring etc. The extent of the plan will then influence the frequency and detail of any contingency training, and the rehearsal of the plan.

Specific advice

Contingency plans are only required for reasonably foreseeable events – just because an event is ‘just about credible’ (e.g. a lorry running into a building and crushing a source), there must be reasonable grounds for believing that the event will occur before contingency plans are required. Whilst the lorry example may not always be deemed credible (after suitable assessment), fire is one event which is usually considered reasonably foreseeable.

The ACoP to IRR17 - Regulations 13, denotes the following as reasonably foreseeable, and therefore requiring contingency plans.

Reasonably foreseeable events requiring a contingency plan

(a) failure of specific control equipment such as shielding, electrical interlocks and warning devices

(b) failure of control measures such as fume cupboards, faulty PPE or misuse leading to exposure

(c) contamination spread from the controlled or supervised area

(d) fire leading to possible dispersal of radioactive material, or melting of lead shielding leading to substantial increases in dose rates

(e) faulty equipment, e.g. X-ray sets

(f) user error for example correct procedures not being followed

(g) loss or theft of radioactive material

We have already suggested that fire is reasonably foreseeable. User error is also reasonably foreseeable, nearly all accidents and incidents have human error as the root course.

Content of contingency plan

Some, or all, of the following needs to be considered.

Likely content of a contingency plan

(a) who is responsible for putting the plan into effect (this must be specified in writing)

(b) what immediate actions for assessing the seriousness of the situation are necessary, for example the use of suitable radiation and contamination monitors (your risk assessment will help you determine this)

(c) what immediate mitigating actions are needed, for instance in clearing the accident area and establishing temporary means of preventing access (a full understanding of your ionising radiation source is essential here)

(d) what emergency equipment is required to deal with identified accidents and where this can be found

(e) other sources of information and guidance, such as equipment manufacturers and contact details (similar accidents already occurred elsewhere?)

(f) what PPE is needed and where it can be found (the training for use of PPE is essential, especially if not worn routinely)

(g) what personal dosimetry requirements there are for people involved in controlling the accident

(h) what training is required for employees (this will include rehearsal - see below)

(i) how to obtain radiation protection expertise so that proper judgements can be made about the seriousness of the situation and recovery measures (it is important to understand what you can do in-house, and where you require immediate RPA advice)

(j) under what circumstances do you contact the emergency services, and who is responsible for doing this (if contact is reasonably foreseeable then liaison and rehearsal is essential)

(k) what dosimetry follow-up is needed so that the people affected by the accident are identified and provision is made for their dose assessment.

The employer must ensure the following is provided:

  • Where local rules are present, they must make reference to the contingency plan – either including a copy of it, or a direct reference to other readily available documentation.
  • The employer must provide sufficient information, instruction and training to all those that might be affected by a radiation accident – and who will need to follow the contingency plans.

With respect to (i) above, there are very few circumstances where immediate RPA advice is appropriate, or would be realistically available. Be cautious if an RPA provider insists that 24/7 cover is essential. What is essential is that the employer should have the local knowledge and resources to provide an immediate response to any reasonably foreseeable accident.

Contingency plan rehearsal

There may be a requirement to ‘exercise’ the contingency plan by carrying out some practice exercises at suitable intervals. The extent to which this is required will depend on the following factors:

  • The potential severity of the accident (as determined by risk assessment)
  • The estimated accident doses that may be received (as they approach dose limits it is likely that rehearsal of the mitigation measures will become more and more important)
  • The number of personnel likely to be involved and the complexity of the plan
  • Involvement of the emergency services

IRR17 – Regulation 13 (2) states that ‘where appropriate, rehearsals of the plan are carried out at suitable intervals’. This may be anything from a table top exercise, to a demonstration of capability using directing-staff and casualty actors. This rehearsal should be documented – and training records made.

Contingency plan use

IRR17 – Regulation 13 requires that if the contingency plan arrangements are required to be implemented (in full or in part) then:

  • the causes of those circumstances are analysed to determine, so far as is reasonably practicable, the measures required to prevent a recurrence
  • a record the analysis is made and kept for at least 2 years from the date on which it was made; and,
  • any exposure which occurs due to the above circumstances is noted on any relevant dose record.

Most larger employers, with the most significant ionising radiation sources, are already likely to have an accident investigation procedure already in place.

If you start from nothing, it is very difficult to get anywhere

– Gerhard Herzberg -