Stress Corrosion Cracking Crack Growth Behavior of Type 316L Stainless Steel Weld Metals in Boiling Water Reactor Environments

Thermal aging and consequent embrittlement of materials are ongoing issues in cast and duplex stainless steels. Spinodal decomposition is largely responsible for the well-known "475 degrees C" embrittlement that results in drastic reductions in ductility and toughness in cast materials. This process is also operative in welds in cast or wrought stainless steels where delta ferrite is present. While the embrittlement can occur after several hundred hours of aging at 475 degrees C, it can also occur at lower temperatures where ductility reductions have been observed after tens of thousands of hours at 300 degrees C. The effect of thermal aging on mechanical properties, including tensile, toughness, fatigue, and static crack growth, has been investigated at room temperature and in 288 degrees C high-purity water simulating boiling water reactor (BWR) operating conditions. The measurements of tensile, microhardness, and Charpy-impact energy show an increase in strength and a decrease in impact energy after aging for up to 10,000 h at 430 degrees C and 400 degrees C. Stress corrosion crack (SCC) growth rates have been measured for as-welded and 5,000-h/400 degrees C aged weld metal at 288 degrees C in high-purity water containing 300 ppb of oxygen. Fracture toughness (J(IC)) have been measured in the 5,000-h/ 400 degrees C aged weld metal and estimated in the other conditions. Crack growth rates for material in the as-welded and aged metalfor 5,000 h at 400 degrees C have been measured and are generally within the scatter band for wrought material, although the aged material data fall at the high end. Unusual in situ unstable fracture behavior has been experienced for material that contains an SCC 'precrack" at toughness values significantly below (<50%) the room temperature fracture toughness. In situ fracture toughness with a fatigue precrack is still significantly below the air values. This behavior, termed "environmental fracture," requires further investigation.close4

Characterization and monitoring of 300 Area facility liquid waste streams during 1994 and 1995

Pacific Northwest National Laboratory`s Facility Effluent Management Program characterized and monitored liquid waste streams from 300 Area buildings that are owned by the US Department of Energy and are operated by Pacific Northwest National Laboratory. The purpose of these measurements was to determine whether the waste streams would meet administrative controls that were put in place by the operators of the 300 Area Treated Effluent Disposal Facility. This report summarizes the data obtained between March 1994 and September 1995 on the following waters: liquid waste streams from Buildings 306, 320, 324, 325, 326, 327, 331, and 3,720; treated and untreated Columbia River water (influent); and water at the confluence of the waste streams (that is, end-of-pipe)

Pacific Northwest National Laboratory 300 area facility liquid effluent monitoring: 1994 and 1995 field tests

Pacific Northwest National Laboratory Effluent Management Services manages liquid waste streams from some of the 300 Area buildings on the Hanford Site near Richland, Washington, to ensure liquid discharges to the Columbia River are in compliance with permit requirements. The buildings are owned by the U.S. Department of Energy and operated by Pacific Northwest National Laboratory. In fiscal year (FY) 1994 and FY 1995, three field tests were conducted to gather information that could be used to (1) increase the understanding of 300 Area building liquid waste streams based on the characterization and monitoring data collected during calendar year (CY) 1994 and CY 1995 and (2) establish improved methods for evaluating facility releases. The three field tests were (1) an evaluation of a continuous monitoring/event-triggered sampling system, (2) a volatile organic compound hold-time study, and (3) an investigation of the dilution and retention properties of the 300 Area process sewer. The results from the first field test showed that future characterization and monitoring of 300 Area facility liquid waste streams could benefit significantly from augmenting continuous monitoring with event-triggered sampling. Current continuous-monitoring practices (i.e., monitoring of pH, conductivity, and flow) cannot detect discharges of organic pollutants. Effluent control effectiveness would be enhanced by incorporating a continuous total organic carbon analyzer in the system to detect events involving releases of organic compounds. In the second field test, sample hold times were shown to have a significant effect on volatile organic compound data. Samples analyzed in the field within 1 hour of collection generally had 1.5 to 3 times higher volatile organic compound concentrations than those analyzed 1.5 to 4 weeks later at on-site and off-site laboratories, respectively. The number of volatile organic compounds detected also decreased with increasing hold times

Mechanical properties of JK2LB at 4K

The jacket of the central solenoid (CS) for ITER is designed to support cyclic tension load generated by the electro-magnetic hoop force during operation. Therefore, the CS jacket material requires high tensile strength, high ductility, and high resistance to fatigue. JK2LB was developed in Japan as a candidate material for CS jacket by using low carbon and boron additions in JK2. The preliminary data of mechanical property for JK2LB without cold work has shown improvement of ductility in comparison to JK2. As a routine multi-party verification process, a series of new mechanical tests including tensile, fatigue crack growth and fracture toughness have been carried out at 4K in MIT for both the base metal and welds of JK2LB. The test materials provided by JAREI were subjected to various cold work and aging before testing. It is found that the cold work has significant impact on the properties. Large variation of the tensile properties is observed. It includes a few specimens with brittle-like behavior. The fracture toughness of JK2LB is greatly reduced after cold work. High notch sensitivity at 4K is observed for side-grooved CT specimens. The current results indicate a need for more tests and studies