Chlorine-36 dispersion in the Chalk River area

Abstract Concentrations of inorganic 36 Cl around the Chalk River Laboratories (CRL) slightly in excess of natural rates of production are a byproduct of reactor operations and radioisotope production at this site. The primary release of the 36 Cl to the atmosphere is via the 50 m main CRL stack which vents air from the reactor facilities. The atmospheric dispersion pattern for this radioisotope is correlated fairly strongly with that of tritium which is also released in low but measurable quantities at CRL. Air, rain, snow and surface water measurements are presented and evaluated. The data have been used to show that the majority of the release is deposited over a relatively small area.