In Situ Stress Corrosion Crack Repair and Prevention for Nuclear Waste Canisters

Period of Performance: 06/12/2017 - 03/11/2018

$150K

Phase 1 SBIR

Recipient Firm

VRC Metal Systems, LLC
525 University Loop Suite 211
Rapid City, SD 57701
Firm POC, Principal Investigator

Abstract

The U.S. depends on its fleet of nuclear facilities for the clean and reliable generation of electricity. With much uncertainty facing long term, permanent storage facilities such as Yucca Mountain, long duration on-site waste storage is becoming a reality. One major problem facing the existing fleet of nuclear waste storage canisters is stress corrosion cracking (SCC) of austenitic stainless steel, particularly on welded joints and in marine environments, such as those found at Diablo Canyon. With the large existing fleet of 304 stainless steel canisters, this problem becomes particularly widespread and significant. Needed is a cost effective repair of stress corrosion cracking, which can be performed in situ and results in a long term and reliable solution. VRC Metal Systems, in collaboration with our academic research partner, SDSM&T, our robotics system developer, Robotic Technologies of Tennessee, propose to apply cold spray technology to mitigate and repair SCC in 304 stainless steel nuclear waste canisters in situ. The repair will arrest crack growth, protect from further corrosion damage, and fully restore the hermetic seal and load carrying capacity of the canister. The small form-factor of the cold spray applicator will allow for the delivery of the cold spray repair within the canister, eliminating the need to disassemble and potentially expose or release high level nuclear waste. Repair of stress corrosion cracking and chlorine induced corrosion cracking stands as a significant safety and economic priority for utilities across the country, and around the world, with failures already occurring in these canisters after only 17 years of service. The development of cold spray repair of these canisters stands as critical enabling technology for the life extension of current long term storage solutions. Additionally, the development of robotic cold spray repair of stainless steel tanks could find applications in other energy sectors, such as fossil fuel storage and processing tanks. The proposed repair method of stress corrosion cracking in nuclear waste storage canisters will indefinitely extended the lifetime of the current fleet of dry storage canisters, which provides both a benefit to the plant owner / operator, as well as the general public. VRC Metal Systems has a proven track record of success transitioning advanced technologies to DOD customers and prime contractors. We will use our quality program management system to coordinate the multidisciplinary team and ensure a successful phase I and transition to phase II and beyond.