This work provides a structural integrity assessment of a spent fuel casks using BS7910. The containment barrier of the casks is designed following ASME Section III. Accordingly, it is necessary to demonstrate the integrity of the materials all along the range of operation temperatures, based on the determination of the corresponding reference temperature for nil-ductile temperature. This approach may be very conservative for the case being analyzed, with a low Lowest Service Temperature, −40°C, established to obtain the Certificate of Compliance for a Type B(U) package. The present work provides an alternative analysis to evaluate and guarantee the structural integrity.
The analysis is based on the use of the BS7910 and a number of engineering conservative assumptions for the treatment of material properties, defect types and loading conditions.
The results show that the cask operation is safe in both Normal Operating Conditions (NOC) and Accidental Conditions (AC), also complying with minimum safety factors established by the nuclear industry for this kind of components and applications.
The work provides a sound original methodology for assessing the structural integrity of casks in cases where the direct application of ASME Code Section III is not capable of demonstrating the absence of non-ductile fracture.
