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[en] The Chernobyl accident in April/May 1986 showed that Norway could be threatened from accidents at nuclear installations further away and to a larger extent then previously thought. From the point of view of decision makers and Government officials, the most important tool missing at that time was a real-time dispersion model implemented in an operational environment for analysing the transport of harmful airborne pollutants. As the institution in Norway responsible for the weather forecasts, the Norwegian Meteorological Institute (DNMI) put high priority on the development of such a tool. SNAP has been developed and implemented at DNMI to simulate large accidental releases of radioactivity from nuclear power plants or other sources. ETEX came as a 'godsend' opportunity to test SNAP against measurements. It also gave us a chance to show (and test) our preparedness in providing real-time predictions of the atmospheric dispersion, transport and evolution of the released tracer
[en] The model: Several Nuclear Accident Program (SNAP) has been developed at the Norwegian Meteorological Institute (DNMI) in Oslo to provide decision makers and Government officials with real-time tool for simulating large accidental releases of radioactivity from nuclear power plants or other sources. SNAP is developed in the Lagrangian framework in which atmospheric transport of radioactive pollutants is simulated by emitting a large number of particles from the source. The main advantage of the Lagrangian approach is a possibility of precise parameterization of advection processes, especially close to the source. SNAP can be used to predict the transport and deposition of a radioactive cloud in e future (up to 48 hours, in the present version) or to analyze the behavior of the cloud in the past. It is also possible to run the model in the mixed mode (partly analysis and partly forecast). In the routine run we assume unit (1 g s-1) emission in each of three classes. This assumption is very convenient for the main user of the model output in case of emergency: Norwegian Radiation Protection Agency. Due to linearity of the model equations, user can test different emission scenarios as a post processing task by assigning different weights to concentration and deposition fields corresponding to each of three emission classes. SNAP is fully operational and can be run by the meteorologist on duty at any time. The output from SNAP has two forms: First on the maps of Europe, or selected parts of Europe, individual particles are shown during the simulation period. Second, immediately after the simulation, concentration/deposition fields can be shown every three hours of the simulation period as isoline maps for each emission class. In addition, concentration and deposition maps, as well as some meteorological data, are stored on a public accessible disk for further processing by the model users
[en] To manage climate change, we need to reduce carbon dioxide emissions from the global energy system to near zero by mid-century. Meanwhile, global energy demand might double from current levels. All credible studies have concluded that to have a serious chance of success, we will likely need all the low carbon solutions we have available to us. In order to meet the Paris climate treaty’s more ambitious goal of limiting global temperature rise to 1.5ºC this century, world carbon dioxide emissions would need to be cut 50% by 2030 and entirely by 2050. To achieve this historically unprecedented societal shift, most of the IPCC scenarios along with numerous other expert projections call for not only the massive expansion of renewable energy, but also major investments in nuclear energy, carbon capture and storage, negative emissions technologies, and for research evaluating geo engineering options. However, some question whether nuclear energy can, or should, play a substantial role in decarbonizing the global energy system. The costs of US and European projects have been high and progress slow, and recent schedule delays and cost overruns at nuclear projects in the Southeastern USA, as well as Finland and France, have further supported these doubts. Are the financial and timing risks of a major nuclear expansion program simply too high? Should we wait for new technologies to emerge? Or is there a way to deploy today’s nuclear technology rapidly and affordably to help us address climate change in time, even as we develop complementary nuclear technologies?