Aging Management Inspections of Dry Shielded Canisters and Horizontal Storage Modules

For the DSC, no aging related observations were seen on any of the DSCs in over twenty years of operations.

AUTHORS
Prakash Narayanan, Karan Mauskar
Orano TN

PRESENTING
March 11, 2025 - Entire white paper will be posted here
Waste Management Symposia

ABSTRACT
The Orano TN Standardized NUHOMS^® Dry Storage System was certified by the NRC under Certificate of Compliance (CoC) No 1004 for an initial storage duration of 20 years. The CoC was renewed for an additional storage duration of 40 years by the NRC which required the implementation of an Aging Management Program (AMP) by the general licensees [1]. The NUHOMS system was originally certified in 1995 and several systems have been stored at various licensee sites for more than 25 years. This paper summarizes the operational experience associated with the aging management inspections performed on Orano TN dry storage systems over the last several years. The inspections were performed to meet the AMP implementation requirements per CoC-1004.

Orano AMP canister crawler robot Remote visual inspections were performed on the Dry Shielded Canister (DSC) and Horizontal Storage Module (HSM) using robotic crawlers capable to perform ASME Level VT-3 and VT-1 inspections. Potential degradation of the stainless steel, welded DSCs and concrete HSMs due to the environment in which they are exposed to, during storage operations is a consideration as part of the AMP. The aging management inspections are developed specifically to address these aging management effects and encompass several sites with varying environmental factors. Special tools and techniques were developed to access the external surfaces of the DSC through limited openings of the inlet vents of the HSM and to control and maneuver the robotic crawlers inside the HSM cavity. The inspection planning applied ALARA principles to ensure that operations conducted in potential high dose areas resulted in the lowest possible exposures.

The paper describes the criteria, equipment, procedures, techniques, lessons learned, and the results of various inspections performed by Orano TN. Further, this paper also correlates the results obtained at various sites to environmental considerations to develop a generic understanding on the aging effects on NUHOMS system components. As part of the Learning Aging Management process, it is important to periodically evaluate the impact of the various environmental and operational factors on the potential for degradation.

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