Dosimetry Requirements

by John Drozdoff, November 30, 1999

TSG [now RPG] has revisited the issue of dosimetry requirements for visitors and contractors in light of proliferation of radiation areas and the draft regulations of the new Nuclear Safety and Control Act.

Radiation areas are defined, for the purposes of this note, as areas where TRIUMF workers are required to wear direct reading dosimeters (DRD's), in addition to TLD badges.

The number of visitors who enter radiation areas is small. There is certainly a well-understood rule that there are to be no frivolous visitor entries to any radiation areas. There are the occassional well-controlled visits by the AECB or contractors preparing a quote, but there is no general Work Permit requirement for a simple entry to a radiation area.

The single DRD issued by Stores should be adequate dosimetry for visitors who enter radiation areas.

The policy that contractors (or anyone else) require a Work Permit to work in radiation areas is also well-understood. All Work Permits issued by all three Operations Groups - 500MeV, ISAC, and ATG - have space for DRD in/out entries that record doses for specific jobs.

It is logical, therefore, for the appropriate Operations Group to issue a second DRD to a contractor working in a radiation area.

The Operations DRD and Work Permit documents and tracks exposure for specific jobs, while the Stores DRD is the DRD record for the site entry.

Both should be returned to the point of issue at the end of each working day.

A further benefit of the two-DRD policy is that the one becomes a backup, should the other be dropped.

TRIUMF still has a responsibility to train staff and contractors should it be necessary to designate them as Atomic Radiation Workers [now Nuclear Energy Workers]. It is at this point that contractors should be issued TLD badges.

The new regulatory dose limit for non-ARW's [non-NEW's] is to be 1mSv per year.