Activity inventory of activated materials in distant components of the CENM TRIGA MARK II reactor for decommissioning planning

• Published in: Progress in nuclear energy (New series) 2025-02, Vol.180, Article 105569
• Main Authors: El Maliki El Hlaibi, S., El Bardouni, T., Boulaich, Y., Nacir, B., El Hajjaji, O., Lahdour, M., Al-Zain, J., Ziani, H., El Yaakoubi, H.
• Format: Article
• Language: English
• Subjects: Activation products; Activity inventory; CENM TRIGA reactor; Decommissioning; Distant components; MCNP6
• ISSN: 0149-1970
• DOI: 10.1016/j.pnucene.2024.105569

This paper presents a methodology for the activity inventory calculations of activated materials in the distant components of the Moroccan TRIGA MARK II reactor after its final shutdown. The induced activity calculations in components further from the core are more complex due to significant neutron flux attenuation away from the core and spatial variations in the neutron energy spectrum. The described method combines reaction rate calculations with the reactor operating history to estimate the neutron-induced activity in distant components. The MCNP6.2 code was used to calculate the neutron flux distributions throughout the reactor and activation reaction rates to estimate the activity inventory in distant components, including the most remote parts of the concrete shielding. Furthermore, the SSW/SSR technique was applied to support calculations in distant components, reducing the computing time and the statistics error. The activity inventory of activated materials in distant components is presented after a cooling period of six months following the final shutdown, and the main contributing radionuclides to the total activity for each material are identified. •Activity inventory of distant components of CENM TRIGA for decommissioning planning.•MCNP6 used for neutron flux distribution and activation reaction rate calculations.•Combining reaction rates with reactor operating history to estimate induced activity.•SSW/SSR applied to support calculations of activation rates in distant components.