title: International challenge to predict the impact of radioxenon releases from medical isotope production on a comprehensive nuclear test ban treaty sampling station.
abstract: The International Monitoring System (IMS) is part of the verification regime for the Comprehensive Nuclear-Test-Ban-Treaty Organization (CTBTO). At entry-into-force, half of the 80 radionuclide stations will be able to measure concentrations of several radioactive xenon isotopes produced in nuclear explosions, and then the full network may be populated with xenon monitoring afterward. An understanding of natural and man-made radionuclide backgrounds can be used in accordance with the provisions of the treaty (such as event screening criteria in Annex 2 to the Protocol of the Treaty) for the effective implementation of the verification regime. Fission-based production of (99)Mo for medical purposes also generates nuisance radioxenon isotopes that are usually vented to the atmosphere. One of the ways to account for the effect emissions from medical isotope production has on radionuclide samples from the IMS is to use stack monitoring data, if they are available, and atmospheric transport modeling. Recently, individuals from seven nations participated in a challenge exercise that used atmospheric transport modeling to predict the time-history of (133)Xe concentration measurements at the IMS radionuclide station in Germany using stack monitoring data from a medical isotope production facility in Belgium. Participants received only stack monitoring data and used the atmospheric transport model and meteorological data of their choice. Some of the models predicted the highest measured concentrations quite well. A model comparison rank and ensemble analysis suggests that combining multiple models may provide more accurate predicted concentrations than any single model. None of the submissions based only on the stack monitoring data predicted the small measured concentrations very well. Modeling of sources by other nuclear facilities with smaller releases than medical isotope production facilities may be important in understanding how to discriminate those releases from releases from a nuclear explosion.
authors.affiliation: Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, WA, 99352, USA. Electronic address: paul.w.eslinger@pnnl.gov.
authors.forename: Paul W
authors.initials: PW
authors.lastname: Eslinger
authors.affiliation: Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, WA, 99352, USA. Electronic address: ted.bowyer@pnnl.gov.
authors.forename: Ted W
authors.initials: TW
authors.lastname: Bowyer
authors.affiliation: Commissariat à l'Energie Atomique, CEA, DAM, DIF, 91297, Arpajon, France. Electronic address: pascal.achim@cea.fr.
authors.forename: Pascal
authors.initials: P
authors.lastname: Achim
authors.affiliation: NOAA/Air Resources Laboratory, College Park, MD, USA. Electronic address: tianfeng.chai@noaa.gov.
authors.forename: Tianfeng
authors.initials: T
authors.lastname: Chai
authors.affiliation: Institut des Radioéléments, Fleurus, Belgium. Electronic address: Benoit.Deconninck@ire-elit.eu.
authors.forename: Benoit
authors.initials: B
authors.lastname: Deconninck
authors.affiliation: AWE, Aldermaston, Reading, RG7 4PR, United Kingdom.
authors.forename: Katie
authors.initials: K
authors.lastname: Freeman
authors.affiliation: Commissariat à l'Energie Atomique, CEA, DAM, DIF, 91297, Arpajon, France. Electronic address: sylvia.generoso@cea.fr.
authors.forename: Sylvia
authors.initials: S
authors.lastname: Generoso
authors.affiliation: Air Force Technical Applications Center, Patrick Air Force Base, FL, USA. Electronic address: philip.hayes.2@us.af.mil.
authors.forename: Philip
authors.initials: P
authors.lastname: Hayes
authors.affiliation: Federal Office for Radiation Protection (Bundesamt für Strahlenschutz, BfS), Frieburg, Germany.
authors.forename: Verena
authors.initials: V
authors.lastname: Heidmann
authors.affiliation: Health Canada, Radiation Protection Bureau, Ottawa, Canada. Electronic address: ian.hoffman@hc-sc.gc.ca.
authors.forename: Ian
authors.initials: I
authors.lastname: Hoffman
authors.affiliation: Japan Atomic Energy Agency, Tokai, Ibaraki, Japan. Electronic address: kijima.yuichi@jaea.go.jp.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Kijima
authors.affiliation: Comprehensive Test Ban Treaty Organization (CTBTO), International Data Center, Vienna, Austria. Electronic address: monika.krysta@ctbto.org.
authors.forename: Monika
authors.initials: M
authors.lastname: Krysta
authors.affiliation: Environment Canada, Canadian Meteorological Centre, Dorval, Canada.
authors.forename: Alain
authors.initials: A
authors.lastname: Malo
authors.affiliation: Zentralanstalt für Meteorologie und Geodynamik, Vienna, Austria. Electronic address: christian.maurer@zamg.ac.at.
authors.forename: Christian
authors.initials: C
authors.lastname: Maurer
authors.affiliation: NOAA/Air Resources Laboratory, College Park, MD, USA. Electronic address: fantine.ngan@noaa.gov.
authors.forename: Fantine
authors.initials: F
authors.lastname: Ngan
authors.affiliation: AWE, Aldermaston, Reading, RG7 4PR, United Kingdom. Electronic address: peter.robins@awe.co.uk.
authors.forename: Peter
authors.initials: P
authors.lastname: Robins
authors.affiliation: Federal Institute for Geosciences and Natural Resources (BGR), Hannover, Germany. Electronic address: ole.ross@bgr.de.
authors.forename: J Ole
authors.initials: JO
authors.lastname: Ross
authors.affiliation: French Institute for Radiation Protection and Nuclear Safety, Fontenay-aux-Roses, France. Electronic address: olivier.saunier@irsn.fr.
authors.forename: Olivier
authors.initials: O
authors.lastname: Saunier
authors.affiliation: Federal Office for Radiation Protection (Bundesamt für Strahlenschutz, BfS), Frieburg, Germany. Electronic address: cschlosser@bfs.de.
authors.forename: Clemens
authors.initials: C
authors.lastname: Schlosser
authors.affiliation: Program on Science and Global Security, Princeton University, Princeton, NJ, USA. Electronic address: schoeppner@princeton.edu.
authors.forename: Michael
authors.initials: M
authors.lastname: Schöppner
authors.affiliation: Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, WA, 99352, USA. Electronic address: brian.schrom@pnnl.gov.
authors.forename: Brian T
authors.initials: BT
authors.lastname: Schrom
authors.affiliation: University of Natural Resources and Life Sciences, Institute of Meteorology and University of Vienna, Department of Meteorology and Geophysics, Vienna, Austria. Electronic address: petra.seibert@univie.ac.at.
authors.forename: Petra
authors.initials: P
authors.lastname: Seibert
authors.affiliation: NOAA/Air Resources Laboratory, College Park, MD, USA. Electronic address: ariel.stein@noaa.gov.
authors.forename: Ariel F
authors.initials: AF
authors.lastname: Stein
authors.affiliation: Health Canada, Radiation Protection Bureau, Ottawa, Canada. Electronic address: Kurt.Ungar@hc-sc.gc.ca.
authors.forename: Kurt
authors.initials: K
authors.lastname: Ungar
authors.affiliation: Health Canada, Radiation Protection Bureau, Ottawa, Canada.
authors.forename: Jing
authors.initials: J
authors.lastname: Yi
mesh_terms: D000396:Air Pollutants, Radioactive / Q000032:analysis*; D005107:Explosions; D008962:Models, Theoretical; D011834:Radiation Monitoring; D018788:Radioactive Hazard Release; D019275:Radiopharmaceuticals; D014980:Xenon Radioisotopes / Q000032:analysis*
chemical_list: D000396:Air Pollutants, Radioactive; D019275:Radiopharmaceuticals; D014980:Xenon Radioisotopes
keywords: (133)Xe; Atmospheric modeling; CTBTO; Medical isotope production; Source-term estimation