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Radiation source leak tests

Sealed radioactive sources must be leak tested periodically to ensure the integrity of their source encapsulations. The leak test protocols depend on the source type and the environment in which the source is used.

Source leak tests are to be conducted in accordance with Annex A.3 of ISO9978 by a person who is appropriately trained and competent. As a minimum, a source leak test is to be conducted:

  • as a precautionary measure when service maintenance is performed on equipment containing sealed radioactive sources (e.g. source changes or shutter maintenance)
  • after an incident.

The wipe test method is a simple and effective test method that satisfies the periodic testing requirements.

Additional requirements for:

  • Industrial gauges
  • Borehole logging equipment
  • Portable moisture/density gauges
  • Lightly encapsulated sources
  • Sources used for educational or experimental purposes.

Guide for source leak test requirements

This is general guidance for source leak test requirements. The radiation safety and protection plan should specify the arrangements for each sealed source.

Industrial gauges

The nearest accessible part to the sealed radioactive source is to be leak tested at least once every 12 months.

This requirement does not apply to sources which are:

  • doubly encapsulated
  • in a stable physical and chemical form (e.g. ceramic)
  • within their recommended working life.

However, if they are mounted in an acidic environment or in proximity to PVC or other material able to produce acids by radiolytic action, then the nearest accessible part to the sealed radioactive source is to be leak tested at least once every 12 months.

Borehole logging equipment

The nearest accessible part to the sealed radioactive source is to be leak tested at least once every 12 months.

Radioactive sources are to be removed from their holders and leak tested at least once every 5 years (This should only happen for sources that have not been hermetically sealed into sondes, e.g. for oil well logging sources where the encapsulated source itself is routinely handled).

Portable moisture/density gauges

The nearest accessible parts to the sealed radioactive sources are to be leak tested at least once every 5 years.

Lightly encapsulated sources

Sealed radioactive sources in handheld, benchtop, or in-stream analysers are to be leak tested on the nearest accessible part to the sources at least once every 12 months.

Licensable ion generators, static eliminators, and serviceable ionisation chamber smoke detectors are to be leak tested on the nearest accessible part to the source (not the actual source as this may cause damage) at least once every 12 months.

Sources used for educational or experimental purposes

Radioactive sources (preferably the actual source capsule) used for educational or experimental purposes are to be leak tested once every 12 months.

Last updated: 26 July 2019