Effect of Bacterial Biofilm on Corrosion of Galvanically Coupled Aluminum and Stainless Steel Alloys under Conditions Simulating Wet Storage of Spent Nuclear Fuel

AbstractDuring spent nuclear fuel reprocessing ruthenium is liable to form black ruthenium deposits on the stainless steel walls of process equipments. These deposits promote corrosion and can eventually obstruct the off-gas lines. The results of decontamination of 304L stainless steel test specimens covered with RuO(OH)

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Welding Process Development for Spent Nuclear Fuel Canister Repair

Volume 1: Codes and Standards ◽

10.1115/pvp2019-93946 ◽

2019 ◽

Cited By ~ 1

Author(s):

Wei Tang ◽

Stylianos Chatzidakis ◽

Roger Miller ◽

Jian Chen ◽

Doug Kyle ◽

...

Keyword(s):

Residual Stress ◽

Stainless Steel ◽

Nuclear Fuel ◽

Arc Welding ◽

Spent Nuclear Fuel ◽

Welding Process ◽

Tensile Residual Stress ◽

304L Stainless Steel ◽

Welding Temperature ◽

Stress Direction

Abstract The potential for stress corrosion cracking (SCC) of welded stainless-steel interim storage containers for spent nuclear fuel (SNF) has been identified as a high priority data gap. This paper presents a fusion welding process that was developed for SNF canister repair. Submerged arc welding (SAW) was developed to weld 12.7 mm (0.5 in.) thick 304L stainless steel plates to simulate the initial welds on SNF canisters. The SAW procedure was qualified following ASME Boiler and Pressure Vessel Code requirements. During SAW, the welding temperature was recorded at various locations by using thermocouples. After SAW, weld microstructures were characterized, joint mechanical properties were tested, and the maximum tensile residual stress direction was identified. After SAW procedure qualification, artificial cracks were excavated perpendicular to the maximum tensile residual stress direction in the SAW heat affected zone. Machine cold-wire gas tungsten arc welding (CW-GTAW) was developed and used for repair welding at cracked locations.

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Crack Growth Rate Testing and Large Plate Demonstration Under Chloride-Induced Stress Corrosion Cracking Conditions in Stainless Steel Canisters for Storage of Spent Nuclear Fuel

Volume 6B: Materials and Fabrication ◽

10.1115/pvp2019-94031 ◽

2019 ◽

Cited By ~ 1

Author(s):

Poh-Sang Lam ◽

Andrew J. Duncan ◽

Lisa N. Ward ◽

Robert L. Sindelar ◽

Yun-Jae Kim ◽

...

Keyword(s):

Growth Rate ◽

Stainless Steel ◽

Crack Growth Rate ◽

Stress Corrosion ◽

Crack Growth ◽

Nuclear Fuel ◽

Stress Corrosion Cracking ◽

Spent Nuclear Fuel ◽

Compact Tension ◽

Corrosion Cracking

Abstract Stress corrosion cracking may occur when chloride-bearing salts deposit and deliquesce on the external surface of stainless steel spent nuclear fuel storage canisters at weld regions with high residual stresses. Although it has not yet been observed, this phenomenon leads to a confinement concern for these canisters due to its potential for radioactive materials breaching through the containment system boundary provided by the canister wall during extended storage. The tests for crack growth rate have been conducted on bolt-load compact tension specimens in a setup designed to allow initially dried salt deposits to deliquesce and infuse to the crack front under conditions relevant to the canister storage environments (e.g., temperature and humidity). The test and characterization protocols are performed to provide bounding conditions in which cracking will occur. The results after 2- and 6-month exposure are examined in relation to previous studies in condensed brine and compared with other experimental data in the open literature. The knowledge gained from bolt-load compact tension testing is being applied to a large plate cut from a mockup commercial spent nuclear fuel canister to demonstrate the crack growth behavior induced from starter cracks machined in regions where the welding residual stress is expected. All these tests are conducted to support the technical basis for ASME Boiler and Pressure Vessel Section XI Code Case N-860.

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