COMPLETION OF RESEARCH pROJECTS USINGRADIOACTIVE MATERIAL

This information sheet outlines the process required when a research project involving the use of unsealed radioactive isotopes has been completed and the research group vacates the radiation laboratory.

It specifically applies to projects that commenced before the adoption of the University’s Policy & Procedures Document in October 2006, where residual waste remains in laboratories that either requires storage past the end of project date for decay or long term storage where there is no disposal path.

Since October 2006 disposal paths for research waste must have been identified as part of the project Risk Assessment.

The process is required to ensure that radioactive material remaining from completed projects is not left as the responsibility of future occupants.

In situations where no disposal path is available it is the responsibility of the Faculty to arrange for, and bear the costs of the removal and long term storage of the material.

If radioactive material can be used by other researchers, the transfer of this will need formal approval of the Head of Department that will receive the material.

Remaining radioactive material

A list of all isotopes and their approximate activities remaining in the laboratory from the research project must be documented.

The form of the material should also be noted. It can be laboratory waste, contaminated biological specimens, contaminated scintillation fluid or unused stock.

The details should be listed in Attachment 1.

Action required

For material that meets the University’s disposal criteria the Chief Investigator should package it appropriately and submit a disposal request to the OHSIM section.

For material that does not meet the disposal criteria there are the several options.

  1. Decay to disposable level

The decay option is only applicable for isotopes with “short”half lives. These include I-125, S-35, P-32 & P-33. This is NOT appropriate for long lived isotopes such as C-14 or H-3.

In operational laboratories, radioactive waste requiring decay prior to disposal is stored for extended periods [a year or more]. The residual activity of this waste is checked at routine intervals to check that it is decaying and is inactive prior to disposal.

In “end of project” situations where it is likely that the research group may leave the University, the situation arises where no one is responsible for the ownership of waste undergoing this decay process or the final disposal.

Therefore “end of project” researchers need to calculate the actual decay time, label the material with this information, place in a dedicated local storage area and notify the University RSO that this material will need to be disposed of after the calculated decay time. Note the decay time in Attachment 1.

The formula to calculate the decay time required is:

t = [T½ ÷ 0.693] x ln [A0 /A]

Where:

t = Decay Time required [in the same units as half-life.

T½ =Half-life of the isotope [usually in days]

A0 = Activity of the isotope [MBq]

A = 4 for P32 & S-35; 0.4 for P-33 & I-125

Common half-lives are:

P-32=4.3 days; S-35=87 days; P-33=25.4 days; I-125= 60 days]

  1. Store indefinitely

For any long lived isotopes such as C-14 or H-3, where disposal is NOT an option, the Chief Investigator must arrange for the material to be transferred to the local long term storage area and advise the Local RSO.

If the laboratory is to remain as a radioisotope laboratory, the material may be stored in the area with other isotopes. It must be clearly labelled, to indicate the isotope, activity, date of purchase, and the name of the researcher. Note the details in Attachment 1.

Clearance

When the above process has been completed, the Chief Investigator should complete the Laboratory Clearance Declaration and/or the Transfer Declaration and forward it together with Attachment 1 to the University Radiation Safety Officer.

LABORATORY CLEARANCE DECLARATION

Chief Investigator:

Research Project:

Room number:

Date project ceased:

As the Chief Investigator of this project I am satisfied that:

  1. All residual radioactive waste, that can be, has been disposed of
  2. All waste requiring decay for disposal has been appropriately stored

Waste awaiting disposal or in long term storage has been placed under the control of:

Staff member:

Date transferred:

Building:

Room:

Chief Investigator:
{insert name}
University Radiation Safety Officer:
Felix Werner
Report Date:

TRANSFER DECLARTION

The following radioactive material has been transferred to:

Staff member:

Building:

Room:

Isotope:

Activity:

Date transferred:

Chief Investigator:
{insert name}
Recipient Head of Department:
{insert name}
Date:

ATTACHMENT 1

END OF PROJECT REMAINING RADIOACTIVE MATERIAL

Laboratory:

Building:

The following radioactive material remains from this research project.

Isotope / MBq / Form / Dispose / Decay/ Store / Storage time
for decay

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