A thermoluminescent dosimetry intercomparison in operational power station fields

Area of Science:

• Medical Physics
• Radiation Dosimetry
• Nuclear Engineering

Background:

• External dosimetry is crucial for monitoring radiation exposure in nuclear facilities.
• Accredited agencies in Canada perform dosimetry for the Atomic Energy Control Board.
• Standardized intercomparisons are essential for validating dosimetry accuracy.

Purpose of the Study:

• To conduct a dosimetry intercomparison among Canadian agencies competent in external dosimetry.
• To assess the accuracy of thermoluminescent dosimeter (TLD) badges under operational conditions.
• To evaluate the consistency of dosimetry services within Candu nuclear generating stations.

Main Methods:

• Thermoluminescent dosimeter badges were exposed in radiation fields within Candu nuclear generating stations.
• Large, block-type phantoms with rotating faces ensured equal exposure for all badges.
• A depth-dose distribution measurement device was used for normalization across 36 exposure runs.
• Data from 522 badges exposed for 1 hour to 2 days were analyzed.

Main Results:

• The average relative readings for the five participating agencies ranged from 1.01 to 1.40.
• Normalization was based on absorbed dose at 1,000 mg cm-2 for each run.
• The study identified variations in dosimetry performance among accredited agencies.

Conclusions:

• The intercomparison revealed a range of performance among external dosimetry providers in Canada.
• Findings underscore the importance of regular dosimetry audits and calibration.
• Ensuring accurate external dosimetry is vital for worker safety in nuclear power plants.