Ionising radiation

Section 4.4 of University Policy S1/12 details the training requirements of all persons involved with work with ionising radiation and includes training syllabuses 6 to 11. The Policy includes the following training matrix for work with ionising radiation:

The University Safety Office provides two standard lectures for new workers:

• Radiation Safety for Laboratory Workers: this is a two hour session that satisfies the 'core of knowledge' (first hour) and 'open source module' (second hour) in the above matrix specifically for staff intending to work with open radioactive sources in university laboratories. The session also meets the needs for open source users who will also be required to use biological irradiators, without their having to attend a separate closed source module
• Safe Use of Closed sources and radiation generators: this is a two hour session that satisfies the 'core of knowledge' (first hour), 'closed source and radiation generators modules' (second hour) in the above matrix. Staff intending to use closed sources (ie discrete laboratory sources or equipment incorporating closed sources) and anyone intending to use an x-ray generator or particle accelerator should attend this session

If an individual’s only intended work with ionising radiation involves a biological irradiator and open sources, it is sufficient that they attend the 'Radiation Safety for Laboratory Workers' session only.

The above Safety Office training sessions provide the necessary information, instruction and training on the radiation protection principles and the fundamental requirements of legislation and University policy. Departments are responsible for supplementing that training, having identified the specific needs of individuals commensurate with their departmental role. The contents of that training should be identified as part of the risk assessment process. However, a suggested syllabus for a department’s task-specific training is available in Appendix 6 of University Policy UPS1/12.

Safety Office training sessions are scheduled at the start of each term and, whenever possible, individuals should attend before starting work with radiation. However, it is accepted that there are occasions when work must commence before an individual worker can attend a scheduled Safety Office provided training session. In this case, the department must ensure that information, instruction and training are provided in house that is applicable to the work undertaken and which addresses the core of knowledge requirements and any standard departmental training. Arrangements should then be made for individuals to attend the next available relevant Safety Office training session.

VIEW SAFETY TRAINING COURSES

No. All persons must receive adequate information, instruction and training before working with ionising radiation to ensure that they are able to work safely and in accordance with legislative requirements, relevant University Policy and departmental procedures.

University Policy S1/12 requires all workers to attend an introductory radiation safety lecture relevant to their proposed work, followed by task specific training provided by the department. This task specific training should satisfy a recommended syllabus outlined in Appendix 6 of the Policy.

It is accepted that there may be occasions when work must commence before an individual worker can attend a scheduled Safety Office provided training session, but this training must be met during the interim period by the department. The department must ensure that every worker has been provided with information, instruction and training that is applicable to the work undertaken and which addresses the core of knowledge requirements, together with the standard departmental training. Arrangements should then be made for individuals to attend the next available relevant Safety Office training session.

VIEW SAFETY TRAINING COURSES

Yes. The process of registration creates a record of the individual working with ionising radiation; the work they are doing; and the location in which that work is carried out. Furthermore, the registration form requires the signature of the radiation protection supervisors who will be responsible for supervising the work in the location it is being performed. A change of location will therefore require the supervision of a new RPS.

REGISTRATION OF RADIATION WORKERS

For example, if you are currently registered to use open sources and you would like to use an x-ray set or a closed source; or if you are currently registered to use P-32 and would like to use S-35.

If the new work will be carried out in your current department, you do not need to complete another registration form. Instead, the Safety office will accept an email from your department’s SRPS requesting that another work category or isotope is added to the conditions of your registration.

Staff whose current registration includes visits to named external institutions may add additional institutions by the same method.

Where work will be carried out in a different department, building or premises and will be supervised by a different SRPS, an entirely new registration form must be completed and submitted to the Safety Office.

Departments should ensure that training needs are reviewed and that individuals’ are provided with necessary information, instruction and training for the new work.

Registration forms are held locally within departments by the Senior Radiation Protection Supervisor (SRPS). Further copies can be obtained from the Safety Office.

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Whole body dosimetry must be provided for:

• individuals who work with closed sources or radiation generators where accessible instantaneous whole body dose rates can exceed 7.5 microsieverts per hour. This should be determined by the risk assessment
• individuals who work with photon emitting isotopes, including positron emitters, in unsealed forms where accessible instantaneous whole body dose rates exceed 7.5 microsieverts per hour. This should be determined by the risk assessment
• individuals who routinely access controlled areas whilst work with radiation is underway
• individuals who have been classified on the basis of potential external body exposures

Extremity dosimetry should be provided for:

• individuals who routinely dispense using unshielded pipettes from 9.25 MBq stocks of high energy beta or positron emitters or manipulate single aliquots of that order
• individuals who routinely manipulate 50 MBq quantities of photon emitting isotopes (other than positron emitters) in single aliquots
• new workers using open sources of high energy beta or photon emitting isotopes, at least initially, to confirm good isotope handling technique
• individuals who have been classified on the basis of potential extremity exposures

Dosimetry will not routinely be provided in the following circumstances:

• individuals working with high energy beta emitters in unsealed forms who are able to work behind suitable polycarbonate shielding.
• individuals working with soft beta emitters (eg ¹⁴C, ³³P, ³⁵S). Dosimetry will not be provided for work with ³H.
• individuals who work with equipment (including radiation generators) permanently installed within a suitably shielded and interlocked facility with accessible instantaneous dose rates during normal operation below 1 microsievert per hour.

Further information relating to the type of dosimetry required in particular circumstances (eg where high dose rates or intakes are possible) is provided in Section 4.9 of University Safety Policy UPS1/12.

With the exception of electronic personal dosimetry, if a dosemeter is required it is provided by the Safety Office. The URPO should be consulted as necessary for advice on the provision of dosimetry.

When travelling through security screening points, your baggage will go through X-ray equipment. Dosimetry that is kept in your bags will receive a significant radiation dose. This is an issue as dosemeters should record your occupational dose, not the dose that they receive from security X-ray scanners. 

We need to differentiate between the dose you may receive from your work and the dose that the dosemeters may receive during transit. We do this by issuing a (yellow) transit dosemeter that must be carried with your routine issue dosemeter(s).

Please contact us to discuss your travel plans and to collect a yellow transit dosemeter from the Safety Office, in advance of your planned travel.

In summary:

• Keep all dosimetry together during transit (see picture below)

• Keep dosimetry out of X-ray scanners if possible (keep them on your person or wear them, many security staff are aware of their purpose)
• Wear only your routine dosemeters for radiation work
• The yellow badge is purely to record dose received to all badges during transit, i.e. not your work
• Return your dosimetry as soon as possible on returning to Oxford if it has been through security X-ray equipment and notify the Safety Office
• Finally, if you have (or suspect you have) been involved in an accident or incident and may have received a dose of radiation, please contact the Safety Office immediately

If your dosemeter is lost, you should make every reasonable attempt to locate it. If it cannot be located, you should notify your radiation protection supervisor, who will be required to inform the Safety Office. Information provided to the Safety Office should include a statement regarding the work that has been performed since the dosemeter was issued, for example 'Worn ten times for routine ⁵¹Cr work without incident'. The notification should include a request for a replacement dosemeter if one is required before the next scheduled issue period.

To minimise the potential for loss, whole body dosemeters should not be left in common areas or attached to laboratory coats. Persons issued with extremity dosemeters should take care when removing disposable gloves that the dosemeter is not retained within the finger of the glove when discarded into the laboratory waste bin. The University is charged by the dosimetry provided for every lost dosemeter.

Inform the Safety Office of lost dosemeter

All pipes and ductwork along which radioactive waste is carried should display a radiation warning sign at appropriate intervals and at obvious access panels such that no-one should be able to break into the pipe/duct without being faced with the following warning:

This drain/duct may contain radioactivity. Do not dismantle it without permission from the Senior Radiation Protection Supervisor.

All departments currently undertaking work with radioactivity will have an appointed senior radiation protection supervisor (SRPS) who must be contacted before any attempt is made to break into the pipe/duct. If the warning is historical, relating to previous radioactive waste disposals in a building that is no longer used for work with radioactivity, the University Radiation Protection Officer should be contacted in lieu of an appointed SRPS. The SRPS must consult the URPO regarding any requests to access an active fume hood duct.

Before permitting the work, the SRPS should first confirm what isotopes have been disposed along the waste run and, by considering their half-life and the most recent disposals, determine whether a radioactive contamination hazard is expected. With the exception of disposal of very short lived isotopes, it should always be assumed that a contamination hazard may exist and therefore internal contamination monitoring must be undertaken at the outset. The SRPS or nominated deputy should be present at the initial stages of the work to perform this monitoring. Where practicable, pipe-work should be flushed with Decon solution prior to dismantling.

Appropriate PPE (disposable gloves, lab coats/overalls and protective eyewear) should be worn at all times.

Pipes should be drained of water as far as possible prior to breaking in. In the presence of the SRPS, building maintenance staff should careful break into the pipe using coupling points where possible, rather than sawing. Where the work involves removal of a section that will retain water (ie a U-bend), the section should be removed over a bucket to catch any spills. The waste water should be disposed of down a sink connected to a separate drain run. The inside of the pipe should then be dried with paper towels. All solid waste generated by the work should be bagged for subsequent disposal depending on the outcome of the contamination monitoring.

Typically, use of hand held radiation monitoring instruments is not possible inside drain runs. Therefore, contamination monitoring should be performed by wipe test and liquid scintillation counting. The only exceptions to this rule are likely to be waste runs where only photon emitting isotopes have been disposed. In any case, wipes must always be performed where pipes/ducts have been used for the disposal of ³H and ¹⁴C waste. Wipes should be made of the internal surfaces of removed sections and at either side of the break. Work must not continue until the results of the liquid scintillation counting are known.

If radioactivity is not detected on the wipes, work can proceed without any special consideration of radioactivity. However, if radioactivity is detected, the SRPS should supervise the entire job until the break in the pipe has been replaced. Dismantling should be carried out by removing complete sections where possible; reconnecting replacement sections using standard couplings. All waste must be disposed of as solid low level radioactive waste in accordance with departmental waste disposal procedures. This will require identification of the constituent isotopes and an estimate of the activity in the waste. The URPO should be consulted for advice as necessary.

On complete reassembly, the drain run should be confirmed to be free of leaks before any aqueous waste disposals are permitted.

Copies of radiation warning signs shown in Appendices 14 and 15 of University Policy S1/12 can be obtained from the University Safety Office.

REQUEST RADIATION WARNING SIGNS

Health Surveillance Guidance, including further information on ionising radiation requirements.