Full numerical approach to demonstrate compliance with safety standards
Résumé
Para. 701 of lAEA's Régulations for the Safe Transport of Radioactive Material (No. SSR 6 Rev. 1, 2018 edition) provides various methods which shall be used to demonstrate the compliance of radioactive materials, packagings and packages with the performance standards required in Section VI of SSR-6: experimental testing with specimens or scale models, reference to previous satisfactory safety demonstrations of sufficiently similar nature, calculation or reasoned argument when the calculation procedures and parameters are generally agreed to be reliable or conservative, or the combination of those methods. Concerning mechanical safety performance in accident conditions of transport required for type B, type C and fissile packages, the conventional demonstration used to be primarily based on experimental testing which could be completed with numerical calculations (justification of the tests' parameters, extrapolation of the tests for the limit parameters of the regulations...). Lately, along with the increasing performance of numerical modeling and calculation, many applicants favor the calculation approach as an alternative for experimental testing, for new package designs. Some limited experimental tests continue to be carried out in order to justify reliability or conservatisms of the numerical approach. In some cases now, the mechanical demonstrations are exclusively numerical. This paper presents IRSN's expectations, feedbacks and issues regarding this full numerical approach, as a technical support organization (TSO), especially concerning:
■ the relevance of the numerical model, behavior law, mesh size and qualification of the code to
reproduce the physical phenomena of interest. These points are very important given the
complexity of the modeling of all components having an impact on the package performance;
■ the definition of criteria to assess the performance of the package designs;
■ the validity domain of the numerical calculations and associated parameters, through sensitivity
studies;
■ the determination and assessment of the global uncertainties associated with the results of the
numerical calculations for studied package designs.
The paper discusses areas where the current regulations could be adapted to address all the
aforementioned issues.
Domaines
Sciences de l'ingénieur [physics]Origine | Fichiers produits par l'(les) auteur(s) |
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