Canadian inter-laboratory organically bound tritium (OBT) analysis exercise

Published in: The Journal of Environmental Radioactivity – August, 2015

Authors: S.B. Kim, J. Olfert, N. Baglan, N. St-Amant, B. Carter, I. Clark, C. Bucur
Canadian Nuclear Safety Commission (CNSC)


Tritium is a radioactive form of hydrogen that occurs both naturally – from interactions of cosmic rays with gases in the upper atmosphere – and as a by-product of the operation of nuclear reactors and tritium processing facilities. The measurement of tritium in the form of tritiated water is well established. However, there is no established standard method for measuring organically bound tritium (OBT) in environmental samples.

A number of members of the CANDU (Canada Deuterium Uranium) Owners Group and international partners participated in a comparative exercise to measure OBT in three different environmental samples: fish, Swiss chard and potatoes.  This study describes the results of the inter-laboratory comparison exercise. Although different laboratories used their own analytical methods in the absence of an established standard OBT method, the study showed that the results of OBT inter-comparison samples were consistent among the different laboratories. The participating laboratories are furthering this work to establish a standard analytical method to measure OBT, and to participate in future inter-comparison exercises using low tritium activity level samples.

The CNSC measures organically bound tritium as part of its environmental monitoring around nuclear facilities to ensure that people and the environment are protected.

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