Remote Repair of Sealed Containers or Dry Storage Casks Containing Used Nuclear Fuel

Currently there are three types of storage systems used to store dry spent fuel: unshielded canisters in vertically-oriented shielded overpacks or silos, unshielded canisters horizontally oriented in concrete modules, and shielded casks. Different types of damage are possible for all three systems. The health and safety of the public will be best protected if the containment and shielding surrounding spent fuel in dry storage remains intact or is restored as soon as possible following a breach. Repairing a damaged storage system if it can be done remotely should provide a significant ALARA benefit compared to removing the fuel and replacing the damaged container since it should reduce the radiation exposure of the personnel involved in the process. If the dry cask storage system were replaced instead of repaired, then there is additional cost associated with disposing of a massive component that may be highly contaminated. A repair process for a damaged system will offer cost savings and a reduction in the radioactive waste produced. The purpose of this project is to develop a working prototype of a remotely operated system for performing repairs on spent fuel dry storage systems. The Phase I project identified the types of damage that could be incurred and determined options for repairing the damage. Based on the studies in Phase I, a concept for a remote repair system was developed that can implement the required repairs. The Phase II work plan is primarily structured around scaling up the Phase I research to full scale hardware; testing a broader range of failure modes and dry storage system geometries; and doing this in an operating environment that closely simulates what will be encountered during a field repair campaign. The concept from Phase I will be fully developed and a prototype system will be fabricated and tested utilizing full-scale, reduced-length non-radioactive canister mockups. The Phase II test program will culminate with at least two simulations; one to represent a horizontal cask and the other to represent a vertical configuration. In these simulations the full-scale, reduced-length, prototype canisters and the prototype repair system will be used to simulate a complete canister repair campaign from start to finish including system setup, canister extraction, defect repair, debris containment, canister reseating, and system teardown.