PRIOR RISK ASSESSMENT FOR WORK WITH IONISING RADIATION :
LEAK TESTING OF SEALED RADIOACTIVE SOURCES
This is a generic assessment for people involved in leak testing of sealed sources of ionising radiation. It
must be adapted to local circumstances. There should be a written testing protocol based on this
assessment. See Work with Ionising Radiation (Approved Code of Practice and Guidance on IRR99)
and AURPO Guidance notes on Working with Ionising Radiations in Research and Teaching (June 2005
Edition).
It covers various isotopes and activities ranging from a few kBq up to GBq amounts.
Locations include controlled areas, supervised areas, un-classified areas.
The main risk is to people taking or handling wipe samples or counting wipe samples. People observing
tests could also be at risk if there was exposure to a large source.
Other people at possible risk are cleaning staff, maintenance staff and contractors maintaining
equipment etc in the area. Members of the public should not be exposed to risks from this work.
Estimation of radiation hazard

Potential hazards:

Irradiation of part or whole of the body to ionising radiations (normally beta or gamma
radiation but other types possible);

Skin contamination with radioactive material leading to irradiation of the body or possible
uptake into the body (the later being particularly significant in the case of sources emitting
alpha radiation).

Estimated radiation dose rates to which anybody could be exposed (in micro Sv/hr): to be
determined on a case by case basis. Sources >1 GBq should be sampled indirectly to avoid
exposure.

Likelihood of contamination being spread: a leaking source could contaminate equipment,
surfaces and people handling them. Removal of sources from equipment could damage them
causing contamination. Likelihood is judged to be low because:

< 2 % leaking sources were detected during the last round of leak tests (Jul 2010);

Sources are not handled directly; and

Sources are not removed from equipment when this could cause damage.

Dosimetry results: evidence is limited but current measurements do not indicate significant
doses.



Area monitoring results: this must be carried out if significant dose rates are anticipated.



Advice from supplier/manufacturer: should be considered, especially for sources located in
equipment and sources larger than 1GBq.
Estimated levels of airborne/surface contamination likely to be encountered: likely to be
negligible if sources are handled carefully. Careless handling could lead to damage to
sources and release of contamination.
Consequences of failure of control measures

Exposure of operator to significant dose of direct radiation from the source as a result of an
error of judgement, poor working practices or misinformation about the activity of the source;

Exposure to contamination from leaking sources due to pre-existing leakage or mishandling
of the source during testing;

Failure to detect leakage due to poor technique or use of inappropriate or inadequately
sensitive monitoring equipment;

Failure to take appropriate action on discovering leakage from a source;

Failure to monitor wipes prior to postage leading to sending radioactive contaminated
material through the post; or

Keeping sources longer than is prudent leading to an increased risk of deterioration of the
encapsulation and subsequent leakage.
Other possible accident situations

Exposure to other sources of radiation in areas where leak testing is taking place; or

Testing sources that are not, in fact sealed, and subsequent spread of contamination.
LEVEL OF RISK: Low if control measures are in place and work is carried out or supervised by
competent persons.
ESTIMATION OF ANY NON RADIATION HAZARDS
Possible hazards are:

Electrical hazards from equipment that sources are located in;

Other equipment related hazards (heat, mechanical hazards, sharp surfaces etc);

Hazards from manual handling of sources and their containers;

Toxic chemical hazards from leaking sources (e.g. americium & plutonium);

Flammable solvent hazards from ethanol used to moisten wipes; and

Physical hazards in the environment in which the testing takes place (slip, trip & fall, contact
hazards, fire, flood etc).
LEVEL OF RISK from these hazards should normally be low and under control. Detailed
consideration of these risks is beyond the scope of this assessment. Significant risks should be
the subject of separate risk assessments.
CONTROL MEASURES:
Dose constraints. Doses must be constrained so that in practice, doses received during leak testing
should be low. Testers should avoid exposure to high activity sources and sources >1GBq should be
tested indirectly.
Dosimetry requirements: these should be determined on a case by case basis and should be
appropriate for the work area and the type of sources handled.
Designation of areas as Controlled or Supervised: criteria set out in Regulation 16 of the Ionising
Radiations Regulations should be applied.
Registration & designation of workers: University staff involved in carrying wipe testing of sealed
sources must be registered as radiation workers. A list must be kept. Designation as a Classified worker
should not normally be required given the activities currently being undertaken in the University.
Laboratory design features:
Wipes should be counted in areas where any contamination can be contained and removed easily. A
sink should be available for hand-washing preferably with hands-free operated taps.
Ventilation/engineering controls, interlocks, safety devices. Not normally applicable.
Access restriction/warning devices/signs, screens etc: as appropriate for the work areas and stores
visited.
Safe systems of work (effectiveness & suitability):

Leak testing must be carried out by competent persons using approved techniques and
monitors that are appropriate for the sources being tested and sufficiently sensitive to detect
signs of leakage;

Tests must be carried out in consultation with the University Radiation Protection Officer

Sealed sources must not be handled directly – forceps, tongs (long-handled if appropriate)
etc must be used;

Sources must be correctly identified with unique identification codes;

Local Rules appropriate for the work areas visited must be followed;

Sources shown to be leaking must be dealt with so that spread of contamination is minimised;
an action plan for the further management of the source and the decontamination of surfaces
and articles which it may have been in contact with must be drawn up;

Pass/fail criteria for leak testing must be as set out.
Personal protective equipment: as appropriate to the area in question and in compliance with Local
Rules.
Monitoring procedures (before during & after experiments):

Work areas should be monitored for possible contamination on completion of testing using
suitable monitors

Wipes destined to be sent through the post must be tested for gross contamination
(contaminated items must not be sent through the post).
Maintenance/testing procedures: equipment used for leak testing must be maintained as necessary.
Faulty equipment must not be used and must be repaired or replaced. Batteries must be adequately
charged. Monitors must be recalibrated by competent persons every year.
Storage & disposal of sources:

Sealed sources must be stored in a safe and secure place;

Appropriate security measures must be in place;

Source accountancy procedures must be in place according to the University Policy..

Departments should have a policy of disposing of sources that exceed their recommended
working life; and

Condemned sources must be disposed of in a safe manner by approved contractors as soon
as practicable.
Training requirements

All persons taking wipes of sources or carrying out leakage tests must be competent to do so;
and

Competence issues should be referred to the University Radiation Protection Adviser.
Health surveillance (including alteration of working conditions of pregnant/breastfeeding workers or
other persons at increased risk)

The need for health surveillance must be assessed on a case by case basis. Iit is unlikely to
be required given the current use of sealed sources in the University);

Exposure of pregnant or breastfeeding women to significant doses of radiation must be
avoided if practicable and in any case, must not exceed the dose limits.
Dose limits: investigational level for workers
It is good practice for the RPSs the University RPO to investigate any doses that are unexpected or
significantly above background. A formal investigation must be carried out for doses (single or
accumulated) exceeding the following limits in a calendar year:

Classified Workers: 3/10 of any of the dose limits for Classified Workers; or

Other workers: any of the limits for Members of the Public.
Emergency procedures and mitigation of the consequences of accidents

There must be an action plan for specifying action to be taken in the case of suspected
significant exposure to radiation or contamination from a sealed source;

If necessary, the advice of the University Radiation Protection Adviser should be sought;

Equipment necessary for decontamination of surfaces and equipment must be readily
available;

People working in the facilities must be instructed in the action to be taken in an emergency;

Where practicable, emergency procedures should be tested periodically.
ACTION PLAN
An Action Plan must be drawn up if the risk assessment identifies any actions that is needed to
Reduce risks to as low a level as is reasonably practicable (ALARP). The plan must specify who will
carry out the actions identified, a timescale for completion; and who is responsible for monitoring the
completion of the work.