Stress Corrosion Cracking Mitigation Coating

Stainless steel dry storage canisters are used for the storage of nuclear waste. Recent work has shown that these containers are susceptible to stress corrosion cracking under conditions that will be present underground, where a combination of chloride-containing dusts and deliquesce leads to a concentrated aggressive aqueous environment. Under these conditions, the weldments of AISI 304/316 are vulnerable to stress corrosion cracking, a potentially catastrophic event. Better corrosion protection is required to ensure long-term safe storage of nuclear waste in dry storage casks. TDA Research will use a novel, highly effective coating system to protect the stainless steel nuclear waste dry storage casks. This coating system has excellent barrier properties to prevent moisture and chloride attack and also contains active corrosion inhibitors. The active inhibitors are designed to stop stress corrosion cracking and pitting on AISI 304/316 steels and will ensure extended corrosion protection for the 20-60 year service life of the dry storage casks. TDA Research will demonstrate the effectiveness of this approach in laboratory testing on AISI 304/316 stainless steel dogbones and u-bends. The test pieces will be sensitized to make them vulnerable to stress corrosion cracking and coated with the protective system. We will conduct slow strain rate testing and U-bend testing to show that we prevent the stress corrosion cracking of the sensitized steel. This corrosion-inhibiting coating system is applicable for nuclear waste dry storage containers and can also be used for austenite stainless steels in chemical and power plants. Stress corrosion cracking can cause disastrous failure to occur unexpectedly, even with a minimal overall loss of material.