Calculations of Induced Activity in the ATLAS Experiment for Nuclear Waste Zoning.

Extensive calculations were performed with the general activation formula using the fluxes of high-energy hadrons and low-energy neutrons previously obtained from simulations with the GCALOR code of the ATLAS detector. Three sets of proton cross-sections were used for hadrons energy above 20 MeV: (a) one set calculated with the YIELDX code (i.e., the Silberberg-Tsao formula of partial proton spallation cross-sections), (b) one set calculated with the Rudstam formula, and (c) the âbest-estimate' dataset which was a compilation of the available experimental and calculated data. In the energy region below 20 MeV, neutron activation cross-sections were taken from evaluated nuclear data files. The activity of each nuclide for a predefined operation scenario (i.e., number and duration of irradiation and shutdown cycles) was normalized to reference values taken from the European or Swiss legislations, to obtain an aggregate estimate of the radiological hazard comparable with a nuclear waste zoning definition criteria that has been adopted by the LHC experiments. The impact of changing the operation scenario and hadrons spallation cross-sections datasets on the zoning was investigated for the 21 most common materials

Predicting induced radioactivity in a large high-energy physics apparatus: The example of the ATLAS experiment

Calculations of induced radioactivity in the ATLAS detector were performed in order to define its radioactive waste zoning. Two independent studies were carried out. The first was based on folding particle flux spectra obtained from the GCALOR code with the radionuclide production cross-sections. The second study was based on extensive calculations with the FLUKA code. This paper describes the two studies in detail; it presents the calculation methods and discusses their advantages and disadvantages. A comparison of their predictions is given. Finally, the paper discusses the designation of the ATLAS radioactive waste zoning on the basis of the combined knowledge gained from both studies. (C) 2008 Elsevier B.V. All rights reserved