Discrimination of Nuclear Explosions against Civilian Sources Based on Atmospheric Radioiodine Isotopic Activity Ratios

A global monitoring system for atmospheric radioactivity is being established as part of the International Monitoring System that will verify compliance with the comprehensive nuclear-test-ban treaty (CTBT) once the treaty has entered into force. This paper studies isotopic activity ratios to support the interpretation of observed atmospheric concentrations of 135I, 133I and 131I. The goal is to distinguish nuclear explosion sources from civilian releases. Simulated nuclear explosion releases along with observational data of radioiodine releases from historic nuclear explosions at the Nevada Test Site are compared to simulated light water reactor releases in order to provide a proof of concept for source discrimination based on radioiodine isotopic activity ratios.