Appendix 27 - Undergraduate work involving unsealed sources
These guidelines have been drawn up in order to restrict the exposure from radiation to undergraduates to the maximum recommended level for members of the general public, i.e. less than 1mSv per year. The quantities of the isotopes given in the table below are not greater than one-tenth of the minimum level which would require a controlled area in relation to the internal hazard and are also, therefore, not greater than the annual limit of intake for each isotope respectively. Where there is additionally an external hazard, the amount of isotope permitted has been further reduced, but some shielding may still be needed to ensure that the instantaneous dose rate, whenever practical, is kept below 2.5µSvh-l.
If the conditions specified for class experiments and project work can be met, then the students will not require individual registration as radiation workers. However, there will still be a requirement on the member of teaching staff responsible for the work to register it, through their DRPS, with the URPA, and indicate the number of students involved.
Prior to any demonstration or experiment involving ionising radiations, the students should be given:
a) instruction in the basic aspects of radiation protection with the importance of keeping doses as low as reasonably achievable (ALARA) being stressed;
b) reassurance with regard to the possible health hazards;
c) a copy of the 'Laboratory Rules - Unsealed Sources' (Appendix 17) - the importance of adhering to these cannot be over-emphasised;
d) the conditions specified in the ratified project application should be complied with.
The provision of information, instruction and training is a specific requirement of Regulation 14 of the Ionising Radiations Regulations 1999.
It is important to remember that all experiments should be carried out with the minimum amount of activity that is practical.
Class Experiments
The amounts specified in column 2 of Table 1 should not normally be exceeded for any one class experiment.
Table 1
| Radionuclide | Suggested Limit for Undergraduate Work (MBq) |
Limit for Supervised Laboratory (MBq) |
| H-3 | 20 |
100 |
| C-14 | 10 |
50 |
| Na-22 | 1 |
5 |
| Na-24 | 1 |
5 |
| P-32 | 1 |
5 |
| S-35 | 10 |
50 |
| Cl-36 | 1 |
5 |
| Ca-45 | 1 |
5 |
| Cr-51 | 10 |
50 |
| Fe-59 | 1 |
5 |
| Rb-86 | 1 |
5 |
| I-125 | 0.1 |
5 |
Where more than one isotope is being used, then a quantity ratio should be calculated, e.g.
80% of P-32 limit
20% of C-14 limit
The dispensing of the stock material should be performed by a registered radiation worker who should be familiar with the hazards associated with the particular isotope in use and the precautions that need to be taken when handling it.
The students should be under supervision at all times whilst radioactive work is in progress.
Project Work
The use of amounts in excess of those specified in column 2 of Table 1 in any one calendar year will not be permitted for any one student who is not registered as a radiation worker. Where more than one isotope is being used, then a quantity ratio should be calculated as above. If greater amounts are required, then the student should register as a radiation worker and the work will have to be performed under the project approved by the URPA.
If the work is performed in a Supervised, then the School/Unit would have a responsibility under Regulation 8(2) of the Ionising Radiations Regulations 1999 to provide the student with 'suitable personal protective equipment'.