Preliminary Investigation on Atmospheric-Induced Stress Corrosion Cracking of British Intermediate Level Nuclear Waste Containers: Residual Stress Analysis and Four Point Bend Exposure Test

2011 ◽  
Vol 110-116 ◽  
pp. 321-327
Author(s):  
Yin Jin Janin ◽  
Stuart B. Lyon ◽  
John Wintle ◽  
Briony Holmes ◽  
Chi Ming Lee
Keyword(s):  
Residual Stress ◽  
Stress Corrosion ◽  
Nuclear Waste ◽  
Stress Corrosion Cracking ◽  
Structural Integrity ◽  
Preliminary Investigation ◽  
Corrosion Cracking ◽  
Intermediate Level ◽  
Stress Profile ◽  
Induced Stress

There are approximately 45,000 Intermediate Level Nuclear Waste (ILW) containers currently stored in the UK at Sellafield and elsewhere. These stainless steels containers should last up to 150 years of surface storage. In this study the general structural integrity of 500L ILW containers were investigated. The associated degradation issue under ambient conditions known as atmospheric-induced stress corrosion cracking (AISCC) has been studied. Preliminary investigation included profiling of residual stress distribution in parent and weld specimens, atmospheric exposure testing under various salts. So far residual stress profile shows high degree of complexity. No cracks have been observed until this moment in time.

Development of Ultrasonic Shot Peening Technique for Reactor Components to Improve Structural Integrity Against Stress Corrosion Cracking

2009 ◽  
Author(s):  
Shohei Kawano ◽  
Ayaka Kawagishi ◽  
Nobuichi Suezono ◽  
Kenichi Ueno ◽  
Ken Okuda ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stainless Steel ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Shot Peening ◽  
Structural Integrity ◽  
Weld Line ◽  
Corrosion Cracking ◽  
Experimental Result ◽  
Ultrasonic Shot Peening

The ultrasonic shot peening (USP) technique has been developed for boiling water reactor (BWR) components as a countermeasure against stress corrosion cracking. The effects on residual stress of USP for type 316L stainless steel and alloy 600 were evaluated. Compressive residual stress layer of 0.5 mm from the surface were formed on the specimens after USP using stainless steel ball with a diameter of 3 mm. Cross-sectional hardness measurement revealed that the increase of hardness due to USP is not significant compared with shot peening (SP). The FEM calculation showed the plastic strain induced by the impacts of 3 φ shot with 5 m/s is lower than those of 0.6 φ shot with 50 m/s. It suggests USP process suppresses the degree of work hardening in comparison with SP process. Dissimilar weld joint specimens which simulate the material and dimension of the shroud weld line H7 were examined to confirm the applicability of USP. The experimental result reveals that USP technique is applicable to reactor internal components as stress modification process.

Development of an Apparatus for Chloride Induced Stress Corrosion Cracking Test Using Immersion Method With Constant Displacement Condition

2019 ◽  
Author(s):  
Jae-Yoon Jeong ◽  
Myeong-Woo Lee ◽  
Yun-Jae Kim ◽  
Robert Sindelar ◽  
Andrew Duncan
Keyword(s):  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Structural Integrity ◽  
Compact Tension ◽  
Corrosion Cracking ◽  
Test Method ◽  
Immersion Method ◽  
Induced Stress ◽  
Displacement Condition ◽  
Constant Displacement

Abstract This paper presents a new test method for assessing chloride induced stress corrosion cracking occurred in metal canisters used for storing spent nuclear fuels. The material applied to experiment is austenitic stainless steel, SS304 similarly used on manufacturing canisters and the experiment is carried out with immersing a compact tension specimen to chloride solution made up with artificial sea salt. Constant displacement condition using bolt tightening is applied to the test and a load is measured as a function of time using a load cell. Five specimens are used for the experiment at temperature of 50 °C for several months and stress intensity factor is calculated through the measured relaxed load and crack length on fractured surface of the specimen. Crack growth rate is presented in terms of test periods and consequently this apparatus suggests a method for evaluating structural integrity of chloride stress corrosion cracking.

NRC/EPRI Residual Stress Validation Program Phase I: Experimental Specimen Modeling and Measurement

2011 ◽  
Author(s):  
J. Broussard ◽  
P. Crooker
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Phase 1 ◽  
Measurement Techniques ◽  
Corrosion Cracking ◽  
Welding Residual Stress ◽  
Hole Drilling ◽  
Pressurized Water

The US Nuclear Regulatory Commission (NRC) and the Electric Power Research Institute (EPRI) are working cooperatively under a memorandum of understanding to validate welding residual stress predictions in pressurized water reactor primary cooling loop components containing dissimilar metal welds. These stresses are of interest as DM welds in pressurized water reactors are susceptible to primary water stress corrosion cracking (PWSCC) and tensile weld residual stresses are one of the primary drivers of this stress corrosion cracking mechanism. The NRC/EPRI weld residual stress (WRS) program currently consists of four phases, with each phase increasing in complexity from lab size specimens to component mock-ups and ex-plant material. This paper describes the Phase 1 program, which comprised an initial period of learning and research for both FEA methods and measurement techniques using simple welded specimens. The Phase 1 specimens include a number of plate and cylinder geometries, each designed to provide a controlled configuration for maximum repeatability of measurements and modeling. A spectrum of surface and through-wall residual stress measurement techniques have been explored using the Phase 1 specimens, including incremental hole drilling, ring-core, and x-ray diffraction for surface stresses and neutron diffraction, deep-hole drilling, and contour method for through-wall stresses. The measured residual stresses are compared to the predicted stress results from a number of researchers employing a variety of modeling techniques. Comparisons between the various measurement techniques and among the modeling results have allowed for greater insight into the impact of various parameters on predicted versus measured residual stress. This paper will also discuss the technical challenges and lessons learned as part of the DM weld materials residual stress measurements.

Effects of Cold Working and Heat Treatment on Caustic Stress Corrosion Cracking of Alloy 800M

2005 ◽  
Vol 297-300 ◽  
pp. 993-998 ◽  
Author(s):  
Chun Bo Huang ◽  
Guang Fu Li ◽  
Zhan Peng Lu ◽  
Jian Min Zeng ◽  
Wu Yang
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Cold Working ◽  
Corrosion Cracking ◽  
Caustic Solution ◽  
Surface Films ◽  
Microstructure Examination ◽  
Increasing Temperature

The effects of cold working and heat treatment on caustic stress corrosion cracking (SCC) of mill annealed (MA) alloy 800M in boiling solution of 50%NaOH+0.3%SiO2+0.3%Na2S2O3 were investigated by means of microstructure examination, tensile test, X-ray stress analysis, SCC testing of C-rings, Auger electron spectroscopy (AES), scanning electron microscopy (SEM) and metallography. The microstructure of alloy 800M under tested conditions was austenite. With a train of 25% by cold working, the grains of alloy 800M became longer, yield strength (YS) and ultimate tensile strength (UTS) increased, elongation (δ ) decreased, residual stress and the susceptibility to SCC increased. With increasing temperature of heat treatment of alloy 800M with cold working, the grains became bigger , residual stress, YS and UTS decreased and δ increased, the susceptibility to SCC of alloy 800M decreased. In boiling caustic solution, SCC cracks on the surfaces of C-ring specimens polarized potentiostatically at –20mV/SCE initiated from pitting and propagated along grain boundaries. AES analysis indicated that the surface films on MA alloy 800M were enriched in nickel and depleted in iron and chromium.

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