Dresden 2011 – scientific programme

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AGA: Arbeitsgruppe Physik und Abrüstung

AGA 1: Fissile Materials and Arms Control

AGA 1.3: Talk

Wednesday, March 16, 2011, 16:30–17:00, BEY 81

Characterisation of Prompt and Delayed Atmospheric Radioactivity Releases from Underground Nuclear Tests at Nevada as a Function of Release Time — •Martin B. Kalinowski — Carl Friedrich von Weizsäcker-Zentrum für Naturwissenschaft und Friedensforschung, Universität Hamburg

A database with information on about 500 cases of atmospheric radioactivity releases from underground nuclear tests is analysed. The data are statistically evaluated and systematically aggregated in order to characterise prompt uncontrolled as well as delayed operational releases of radioactivity into the atmosphere. Conclusions are drawn on the main features of releases that can be expected from underground nuclear tests as a function of release time. These findings are relevant for developing and validating methods to be applied in global monitoring of atmospheric radioactivity to verify compliance with the Comprehensive Nuclear-Test-Ban Treaty (CTBT).

The Nevada data are consistent with full in-growth from the precursors prior to release irrespective of the release time. As a conclusion, there is no significant fractionation between the xenon isotopes and the precursors on any of the relevant pathways of operational releases. Though less data are available for uncontrolled releases, the same conclusion appears likely. The spread over many orders of magnitude observed for xenon isotopic ratios can mainly be related to the activity change with time. Accordingly, the isotopic ratios are a reliable parameter to facilitate source discrimination and assessment of the event time.