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Description
The upgrade of the storage ring of Synchrotron SOLEIL, the French 3rd generation synchrotron light source, to a 4th generation ring, based on multi-bend achromat to achieve a very low emittance electron beam (~80 pm.rad), has entered the TDR phase.
This upgrade will led to the decommissioning of the present storage ring. In France, it is mandatory before the shutdown to submit to the French Nuclear regulation Authority (so call ASN) a demand of authorisation for both the decommissioning of present storage ring and to operate the new one.
If, in France, there are no real clearance levels for induced radioactive materials, there is a brand-new regulation that allows nuclear waste recovery only for very low induced radioactivity of metallic materials if able to be recycled by a dedicated industrial partner and below both total (Bq) and specific radioactivity (Bq/g) threshold levels. Our application for decommissioning authorisation must bring the demonstration that the induced radioactivity of the storage ring components will be below these very demanding criteria.
This paper presents the methodology, calculations and measurements that will be conducted to evaluate the actual induced radioactivity that will be present in the storage ring components at the moment of the shutdown. This study will mainly rely on Monte Carlo simulations, thanks to the capabilities of FLUKA4-2 code, based on a very detailed geometry, as accurate as possible, including the magnetic fields produced by the storage ring magnets and realistic beam loss pattern as observed and measured during operation nowadays to comply with ASN’s requirements.