Radionuclide observables of underwater nuclear explosive tests. (December 2018)

• Record Type: Journal Article
• Authors: Burnett, Jonathan L.; Milbrath, Brian D.
• Is Part Of: Journal of environmental radioactivity. Volume 192(2018)
• Page Start: 160
• Page End: 165
• Publication Date: 2018-12
• Subjects: Radioactivity -- Periodicals; Radiation, Background -- Periodicals; Radioecology -- Periodicals; Radioactive pollution -- Periodicals; Environmental Pollutants -- Periodicals; Radioactive Pollutants -- Periodicals; Radioactivity -- Periodicals; Radioécologie -- Périodiques; Pollution radioactive -- Périodiques; Fond de rayonnement -- Périodiques; 539.752
• DOI: 10.1016/j.jenvrad.2018.06.007
• Languages: English
• ISSNs: 0265-931X

Abstract

Abstract: There remain technical challenges for an On-site Inspection (OSI) in the high seas environment, which gathers evidence of a violation of the Comprehensive Nuclear-Test-Ban Treaty (CTBT). For terrestrial nuclear explosions, the radionuclide observables are well defined and States Parties have chosen 17 particulate radionuclides that allow discrimination from other nuclear events. However, an underwater nuclear explosion generates induced radionuclides from the neutron activation of seawater, which has the potential to interfere with the measurement of the radionuclide observables using gamma-spectrometry techniques. To understand these effects the inventory of OSI relevant (6.0 × 10 16 Bq) and activation (1.6 × 10 19 Bq) radionuclides has been calculated for a 1 kT underwater nuclear explosion. The activation products consist predominantly of 38 Cl and 24 Na, which decay to 5.56% and 0.0007% of their initial activity within 1 and 14 days. Monte Carlo techniques have been used to assess spectral interferences within this timeframe. It is demonstrated that during this period they do not interfere with the measurement of the existing radionuclide observables. Additionally, 24 Na has been identified as useful for inspection purposes. Highlights: An underwater nuclear explosion will generate induced radionuclides from the neutron activation of seawater. The activation radionuclides may interfere with the gamma-spectrometry of radionuclide observables used for an OSI. The radionuclide observables and seawater activation products has been calculated for a 1 kT underwater nuclear explosion. Modelling has been used to assess gamma-spectrometry interferences and identify additional radionuclides useful for OSI purposes.