Harri Toivonen

Atmospheric transport modelling in support of CTBT verification—overview and basic concepts

Abstract Under the provisions of the Comprehensive Nuclear-Test-Ban Treaty (CTBT), a global monitoring system comprising different verification technologies is currently being set up. The network will include 80 radionuclide (RN) stations distributed all over the globe that measure treaty-relevant radioactive species. While the seismic subsystem cannot distinguish between chemical and nuclear explosions, RN monitoring would provide the “smoking gun” of a possible treaty violation. Atmospheric transport modelling (ATM) will be an integral part of CTBT verification, since it provides a geo-temporal location capability for the RN technology. In this paper, the basic concept for the future ATM software system to be installed at the International Data Centre is laid out. The system is based on the operational computation of multi-dimensional source–receptor sensitivity fields for all RN samples by means of adjoint tracer transport modelling. While the source–receptor matrix methodology has already been applied in the past, the system that we suggest will be unique and unprecedented, since it is global, real-time and aims at uncovering source scenarios that are compatible with measurements. Furthermore, it has to deal with source dilution ratios that are by orders of magnitude larger than in typical transport model applications. This new verification software will need continuous scientific attention, and may well provide a prototype system for future applications in areas of environmental monitoring, emergency response and verification of other international agreements and treaties.

Transport of radioactive particles from the Chernobyl accident

Abstract After the Chernobyl accident large and highly radioactive particles were found in several European countries. Particles > 20 μm in aerodynamic diameter were transported hundreds of kilometres from the plant, and they were sufficiently active (> 100 kBq) to cause acute health hazards. Here, a particle trajectory model is used to identify the areas of large particle fallout. Effective release height of the particles and atmospheric phenomena related to their transport are investigated by comparing particle findings with locations given by trajectory calculations. The calculations showed that in the Chernobyl accident either the maximum effective release height must have been considerably higher than previously reported (> 2000 m) or convective warm air currents may have lifted radioactive material upwards during transport. Large particles have been transported to other areas than small particles and gaseous species. The particulate nature of the release plume must be taken into account in dispersion and transport analyses. Air parcel trajectories alone are not necessarily sufficient for identifying the fallout area of radioactive material.

Determination of 235 U, 239 Pu, 240 Pu, and 241 Am in a nuclear bomb particle using a position-sensitive α-γ coincidence technique

A nuclear bomb particle containing 1.6 ng of Pu was investigated nondestructively with a position-sensitive α detector and a broad-energy HPGe γ-ray detector. An event-mode data acquisition system was used to record the data. α-γ coincidence counting was shown to be well suited to nondestructive isotope ratio determination. Because of the very small background, the 51.6 keV γ rays of (239)Pu and the 45.2 keV γ rays of (240)Pu were identified, which enabled isotopic ratio calculations. In the present work, the (239)Pu/((239)Pu+(240)Pu) atom ratio was determined to be 0.950 ± 0.010. The uncertainties were much smaller than in the previous more conventional nondestructive studies on this particle. Obtained results are also in good agreement with the data from the destructive mass spectrometric studies obtained previously by other investigators.

EMCCD imaging of strongly ionizing radioactive materials for safety and security

In this work, an electron-multiplying camera is introduced for the first time for rapid alpha imaging in a glovebox. To demonstrate the technique, fuel pellets containing uranium and plutonium isotopes were measured at the Institute for Transuranium Elements, Karlsruhe. Further development of the EMCCD imaging system can evolve to a viable tool for security and safety officials around the world. The method has potential to be used in crime scene investigation if illicit use of alpha active materials is suspected. Other applications lie in the field of nuclear industry and especially in decommissioning of old facilities.

Event Mode Data Acquisition for Characterization of Samples Containing Radioactive Particles

The use of double-sided silicon strip detectors and alpha-gamma coincidence technique, among others, for the characterization of samples has been studied. Encouraging results including an improved detection capability of transuranic elements are reported. Based on these results, a project was initiated to develop and improve analysis of samples. The overall project including a new measurement system called PANDA is introduced.

European Reference Network for Critical Infrastructure Protection: - Novel Detection Technologies for Nuclear Security

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After-action Analysis of the Magic Maggiore Workshop on Expert Support and Reachback

...................................................................................... 5 1 Scope and structure of the workshop ............................................. 6 2 Main findings .............................................................................. 6 3 Workshop conclusions — key takeaways ........................................ 9 4 After-action analysis by the ERNCIP Thematic Group Radiological and Nuclear Threats to Critical Infrastructure — Reachback sub-group ...... 10 4.1 Awareness raising ............................................................................. 10 4.2 Scientific, technical and operational expert support ................................ 11 4.3 Alarm adjudication ............................................................................ 12 4.4 CBRNE threat management — integrated prevention, detection and response ............................................................................................... 12 4.5 International issues ........................................................................... 14 European Reference Network for Critical Infrastructure Protection After-action Analysis of the Magic Maggiore Workshop on Expert Support and Reachback 5 European Reference Network for Critical Infrastructure Protection (ERNCIP Project) https://erncip-project.jrc.ec.europa.eu Abstract The European Commission’s Joint Research Centre (JRC) in collaboration with the Global Initiative to Combat Nuclear Terrorism (GICNT) organised a two and a half-day workshop on expert support and reachback entitled Magic Maggiore at the JRC Ispra, Italy in 28-30 March 2017. Through a series of presentations, case studies, panel discussions, and a demonstration exercise, Magic Maggiore helped raise awareness and build commitment towards technical reachback. Furthermore, the workshop presented best practices to address key challenges, and identified areas for future work in this field. The workshop included a real-time detection and reachback exercise of a hypothetical nuclear security incident, put on between the JRC (Ispra) and France (Paris). The demonstration focused on core components of alarm adjudication and information exchange between front-line officers, a national reachback centre, and an advanced centralised reachback centre located in Paris. A list of concrete post-workshop activities has been generated. The purpose of the list is to pave the way for the identification of the next steps towards development of European capabilities for nuclear security and in more general, for CBRNE security. Reachback is necessary for alarm adjudication to provide timely information for a balanced response. Information sharing between competent authorities is of vital importance for nuclear security. Due to the variety of responsibilities, Technical, Scientific and Operational support needs to be defined. The Member States should consider developing joint protocols on data structures and data handling to ease the information flow and so the response time. European Reference Network for Critical Infrastructure Protection After-action Analysis of the Magic Maggiore Workshop on Expert Support and Reachback 6 European Reference Network for Critical Infrastructure Protection (ERNCIP Project) https://erncip-project.jrc.ec.europa.eu 1 Scope and structure of the workshop The European Commission’s Joint Research Centre (JRC) in collaboration with the Global Initiative to Combat Nuclear Terrorism (GICNT) organised a two and a half-day workshop on expert support and reachback entitled Magic Maggiore at the JRC Ispra, Italy from 28-30 March 2017. The workshop brought together more than 60 experts from 25 countries, and representatives from the European Commission (EC) and the International Atomic Energy Agency (IAEA). Most of the participants were technical, scientific, or operational experts on detection of and response to a nuclear security event, including information sharing, data processing, alarm adjudication and technical responsibilities, such as running and sustaining large detection networks for nuclear security. The workshop included a series of presentations and panel discussions to introduce the key themes for the discussion with a particular focus on the roles and responsibilities of expert support. A deep dive was made into three common reachback challenges: information sharing, alarm adjudication, and detection technology. Also, the impact of the new technology on nuclear security detection architectures was analysed. National-level presentations were included to identify the core components of different reachback systems. Supporting panel discussions were focused on scaling and sustaining reachback capabilities. A real-time detection demonstration was organised between the JRC and France to show how the front-line officers (FLO) and the reachback centre could work together to resolve a complex nuclear security event.

Erratum: Optical detection of radon decay in air.

Scientific Reports 6: Article number: 2153210.1038/srep21532; published online: February122016; updated: April222016 The HTML version of this Article contained a typographical error in the volume number ‘6’, which was incorrectly given as ‘5’. This has now been corrected. In addition, there were typographical errors in the Abstract. “Radon decay is directly measured by observing the secondary radiolumines cence light that alpha particles excite in air,” now reads: “Radon decay is directly measured by observing the secondary radioluminescence light that alpha particles excite in air,” “The presented technique paves the way for optical approaches in rapid radon detec tion,” now reads: “The presented technique paves the way for optical approaches in rapid radon detection,” These errors have now been corrected in the PDF and HTML versions of the Article.

List-mode data acquisition based on digital electronics - State-of-the-art report

41 pags. 3 tabs.; 3 app.; EUR 26715 EN – Joint Research Centre – Institute for the Protection and Security of the Citizen