DRS Policy Requirements
In the case of a laboratory inactivation, move, or renovation, the DRS must be contacted to ensure the laboratory has been decontaminated to levels acceptable for public use, as such actions may involve non-occupational workers. Contact the area health physicist as early as possible to help facilitate the process.
Review this checklist for clearance guidelines regarding (1) laboratory inactivation, moves, partial or whole lab renovations, and (2) potentially contaminated items or equipment that will be released for disposal or unrestricted (non-radioactive material) use.
Direct DRS involvement with equipment clearance is not typically required, except for liquid scintillation and gamma counters (see below). DRS should also be consulted for fume hoods that used volatile radioactivity and objects with complicated internals.
The Authorized User (AU) who owns any equipment in which radioactive materials have been used or stored is responsible for surveying and decontaminating those items as necessary before they are sent to surplus, repaired, released for non-radioactive material use, or moved by non-occupational workers or movers. Upon successful decontamination, all "Caution Radioactive Material" labels or tape must be removed or defaced.
Please note that moving an LSC or gamma counter within the NIH campus without first removing and/or re-installing the lead shielding could result in damage to the internal source or other parts of the instrument. Contact the appropriate vendor for lead removal/re-installation prior to moving an LSC or gamma counter.
Liquid Scintillation and Gamma Counters
Liquid Scintillation Counters
Because some liquid scintillation counters (LSCs) contain an internal radioactive source, the equipment manufacturer or service representative must be contacted to first determine if there is an internal source.
If the unit does contain an internal source:
The AU is required to have the internal source removed and disposed of by the LSC manufacturer or service representative prior to sending the unit off campus for repair or disposal. The DRS cannot perform this activity due to license regulations.
If the LSC is being moved from one location to another on the NIH campus:
The internal source does not have to be removed. However, the internal source must be removed if the unit is being relocated between the NIH campus and an off-campus building under NIH control. The lab staff must also perform a contamination survey of the counter prior to the unit being sent off campus for repair, relocation, or disposal. The unit must first also be monitored with a portable meter in areas that could be contaminated. Examples include the controller keyboard or where contaminated liquid could have spilled from a counting vial. Any contaminated areas must be decontaminated.
Once it has been determined if the unit contains an internal source and one of the appropriate action has taken, a minimum of 5 swipes should be performed to determine if any loose removable surface contamination exists. A map of where the swipes were taken should be made, and the swipe counting results should be retained for three years. The swipe map and counting results should be given to the area health physicist for review. The AHP will attach a DRS clearance sticker that will allow the unit to be removed and disposed.
Upon completion of the source removal and swipe survey, the laboratory staff must contact the area health physicist to schedule an official DRS clearance before the LSC is removed from the lab.
Gamma counters usually require the use of an external sealed source for calibration. Nevertheless, the AU should contact the manufacturer or service representative to ensure there are no internal sources. If no internal source exists or has been removed, the AU will have the unit checked for contamination as outlined above.
If any external sealed calibration or quench sources were used with the LSC or gamma counters, they are to be disposed of as radioactive waste through the DRS waste contractor.
Radiation-producing machines do not require special clearance due to the absence of radioactive material during use. Examples of these machines include:
- Cabinet x-ray units
- X-ray diffraction units
- Electron microscopes
- Radiographic and fluoroscopic x-ray units
As periodic safety inspections are performed on these machines by a DRS contractor, the laboratory staff must notify DRS when new units are purchased or old units will be moved or disposed.
Devices containing radioactive sources
Devices containing radioactive sources or radioactive static charge eliminators are controlled, subject to federal regulations, and are inventoried by the DRS. Examples of these devices may include the following:
- Self-shielded irradiators containing sealed source Cs-137 or Co-60
- Mass spectrometers
- Gas chromatographs
- Lead paint analyzers
The laboratory staff must notify DRS prior to the relocation, repair, or disposal of such items. The area health physicist should be contacted for assistance in determining the proper clearance procedures.