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Microstructure and In-Service Degradation of Baffle-Former Bolts – In-Core Components of Light-Water Reactors, ORNL/TM-2023/311823814Specimen surfaces that are exposed to high-temperature, high-pressure water exhibited signs of in-service corrosion degradation. EBSD and EDS analyses highlighted intergranular corrosion, possible grain boundary oxidation at depths of less than 3 μm, and unexpectedly, short cracks filled with Cr-rich oxides measuring approximately 5–6 μm.4/5/2024 5:51:43 PMORNL/TM-2023/3118 M3LW-23OR0402027 ORNL IS MANAGED BY UT-BATTELLE LLC FOR THE US DEPARTMENT OF ENERGY Reports produced after January 1, 1996, are generally available free via 25https://lwrs.inl.gov/Materials Aging and Degradation/Forms/AllItems.aspxpdfFalsepdf2023-09-29T06:00:00Z
Spread Spectrum Time Domain Reflectometry (SSTDR) and Frequency Domain Reflectometry (FDR) for Detection of Cable Anomalies Using Machine Learning, PNNL-34821275555Cables are initially qualified for nuclear power plant use for 40 years. As plants extend their operating license to 60 and 80 years, continued use of these cables must shift to a performance-based approach since it is cost prohibitive to completely replace cables that are likely still capable of performing their design function. A variety of cable tests are available and are commonly applied during outages when the cables can be taken out of service.12/14/2023 9:25:34 PMU.S. Department of Energy Office of Nuclear Energy This information was prepared as an account of work sponsored by an agency of the U.S. Government A variety of cable tests are 188https://lwrs.inl.gov/Materials Aging and Degradation/Forms/AllItems.aspxpdfFalsepdf2023-09-26T06:00:00Z
Extended Bandwidth Spread Spectrum Time Domain Reflectometry Cable Test for Thermal Aging, Low Resistance Fault, and Water Detection, PNNL-34815275556In 2022, researchers at Pacific Northwest National Laboratory (PNNL) used the Accelerated and Real-Time Environmental Nodal Assessment (ARENA) cable and motor test bed to characterize spread spectrum time domain reflectometry (SSTDR) and compare the responses of an SSTDR instrument to those of a frequency domain reflectometry (FDR) instrument. Results showed both techniques could detect and locate cable anomalies such as phase-to-phase low resistance and shorts, thermal insulation damage, mechanical insulation damage, and the presence or absence of water in some conditions. The SSTDR tests used a commercial instrument provided by LiveWire Innovations Inc. This commercial instrument performed tests at 6, 12, 24, and 48 MHz bandwidth. The results of these tests were compared to FDR tests where bandwidths could be extended up to 1.3 GHz, although the best responses for cable tests were from 100 to 500 MHz. Lower bandwidth signals can propagate better along the cable while higher bandwidths have higher resolution for impedance change reflections allowing more precise indication of location and separation of anomalies.9/20/2023 4:02:00 PMU.S. Department of Energy Office of Nuclear Energy This information was prepared as an account of work sponsored by an agency of the U.S. Government The results of these tests were 56https://lwrs.inl.gov/Materials Aging and Degradation/Forms/AllItems.aspxpdfFalsepdf2023-09-26T06:00:00Z
Complete the additional microstructural evaluation and SCC CGR testing on two heats of aged Alloy 152, ANL/LWRS-23/1275557Nickel-based Alloy 690 and the associated weld Alloys 52 and 152 are typically used for nozzle penetrations in replacement heads for pressurized water reactor (PWR) vessels, because of their excellent overall resistance to general corrosion and environmental degradation, primarily stress corrosion cracking (SCC). However, many of the existing PWRs are expected to operate for 40-80 years. Likewise, water-cooled small modular reactors (SMRs) will use Ni-Cr alloys and are expected to receive initial operating licenses for 60 years. Hence, the thermal stability of Ni-Cr alloys is critical for the long-term performance of both existing and advanced nuclear power plants, and possibly spent fuel storage containers.9/20/2023 4:14:50 AMEffect of thermal aging on microstructure and stress corrosion cracking behavior of Alloy 152 weldments Argonne is a U.S. Department of Energy laboratory managed by UChicago 41https://lwrs.inl.gov/Materials Aging and Degradation/Forms/AllItems.aspxpdfFalsepdf2023-09-26T06:00:00Z
Applying grain-boundary sensitive electrochemical scanning probe techniques to evaluate intergranular degradation of irradiated and deformed stainless steels, AM3LW-23OR04020211275558In nuclear power plants, IASCC of the critical structural components can cause frequent shutdown of the nuclear reactor. This results in the power generation loss and incurring high maintenance cost. IASCC is a complex problem where the synergetic effect of irradiation, mechanical load, and corrosion activity all comes into play, thereby making its mechanism difficult to understand. Irradiation assisted elemental segregation (e.g., Cr-depletion at grain boundaries) can be the major reasons to induce IASCC, but the corrosion activity related to such compositional heterogeneities has not been fully understood.9/26/2023 8:53:45 PMU.S. Department of Energy Office of Nuclear Energy This information was prepared as an account of work sponsored by an agency of the U.S. Government IASCC is a complex problem where 31https://lwrs.inl.gov/Materials Aging and Degradation/Forms/AllItems.aspxpdfFalsepdf2023-09-26T06:00:00Z
The Mechanism of Irradiation Assisted Stress Corrosion Cracks in Stainless Steels, M2LW-23OR0402029275561The objective of this Light Water Reactor Sustainability (LWRS) project is to determine the mechanism of irradiation-assisted stress corrosion cracking (IASCC) in austenitic stainless steels in a PWR primary water environment and to propose mitigation strategies. A novel miniaturized four-point bend test was used to determine the crack initiation stress and to relate it to the microstructure features responsible for crack initiation. In this current work, we lay out the mechanism of IASCC as deduced from work in this LWRS program, complimentary programs and work done by others over the past 60 years. Despite evidence of this degradation mode that dates back to the 1960s, the mechanism by which it occurs has remained elusive. 9/18/2023 7:55:02 PMSeptember 2023 U.S. Department of Energy Office of Nuclear Energy M2LW-23OR0402029 ii DISCLAIMER This information was prepared as an account of work sponsored by an agency of 74https://lwrs.inl.gov/Materials Aging and Degradation/Forms/AllItems.aspxpdfFalsepdf2023-09-26T06:00:00Z
Status of Cable Aging Knowledge Gaps Identified in the Expanded Materials Degradation Assessment (EMDA)62804Knowledge gaps identified in the Expanded Materials Degradation Assessment (EMDA), Volume 5: Aging of Cables and Cable Systems represent concerns that the assumptions made in 40-year environmental qualification of cables may be weak, that the pre-aging of cables prior to LOCA testing may have represented less than 40-year equivalence, and that consequently the EQ process may not be conservative and thereby overpredict cable useful lifetime. 1/15/2024 4:55:20 PMU.S. Department of Energy Office of Nuclear Energy This information was prepared as an account of work sponsored by an agency of the U.S. Government It begins with a discussion of 24https://lwrs.inl.gov/Materials Aging and Degradation/Forms/AllItems.aspxpdfFalsepdf2023-09-15T06:00:00Z
Complete the first phase of the comprehensive characterization of repair welding performed on irradiated Ni alloy182 using stress improved laser welding in collaboration with EPRI,ORNL/TM-2023/3109275562This report describes the research activities conducted in FY 2023 on post-weld evaluation and characterization of the quality and properties of welds made on irradiated Ni-base alloy 182 (with boron concentration up to 15 wppm) by the advanced laser repair welding technology developed under the DOE Light Water Reactor Sustainability Program and EPRI LTO program. The research represents a major progress in repair welding of highly irradiated helium containing reactor internals and its feasibility to use the ABSI-LW technology developed in this program. 9/15/2023 4:31:57 PMU.S. Department of Energy Office of Nuclear Energy This information was prepared as an account of work sponsored by an agency of the U.S. Government This report fulfills the FY 2023 56https://lwrs.inl.gov/Materials Aging and Degradation/Forms/AllItems.aspxpdfFalsepdf2023-09-15T06:00:00Z
Comprehensive Characterization of Helium-induced Degradation of the Friction Stir Weld on Neutron Irradiated 304L Stainless Steel, ORNL/TM-2023/3088283610Fractography analysis showed mostly ductile fracture with some brittle areas, related, as believed, to the helium-rich spots. From the BM observation, such helium enriched spots might be produced artificially in the BM production but needs further characterization to determine. Helium-rich spots led to localized fracture effects along the specimen edges and probably in the bulk. Helium-related issues were the most pronounced in the top retreating side (TR) specimen, leading to delamination effects.10/11/2023 2:33:54 AMORNL/TM-2023/3088 M3LW-23OR0406013 ORNL IS MANAGED BY UT-BATTELLE LLC FOR THE US DEPARTMENT OF ENERGY Reports produced after January 1, 1996, are generally available free via 39https://lwrs.inl.gov/Materials Aging and Degradation/Forms/AllItems.aspxpdfFalsepdf2023-09-12T06:00:00Z
FY 2023 Progress on Stress Corrosion Crack Testing of Ni-Base Alloys in PWR Primary Water, M2LW-23OR04020311280727The first part of this report documents the final year progress of a three-year research effort on evaluating the SCC initiation and growth behavior of Ni-base alloys in LiOH vs. KOH-containing PWR primary water. The material types and the specific water chemistry conditions evaluated in this research were selected based on discussions with EPRI, who is assisting the U.S. pressurized water reactor utilities in a potential transition from LiOH to KOH.8/30/2023 5:33:05 AMU.S. Department of Energy Office of Nuclear Energy This information was prepared as an account of work sponsored by an agency of the U.S. Government The first part of this report 64https://lwrs.inl.gov/Materials Aging and Degradation/Forms/AllItems.aspxpdfFalsepdf2023-08-29T06:00:00Z