Abstract

Gypsum dissolves rapidly underground and at the surface, forming gypsum karst features that include caves, subsidence areas, and sinkholes. Mapping these landforms, understanding the gypsum karst and local hydrogeology, and producing sinkhole susceptibility and hazard maps are crucial for development and public safety. Situations that change the local hydrogeology, such as dams, water abstraction, or injection/drainage, can accelerate dissolution and subsidence processes, increasing the severity of the problems; dams and canals built on gypsum karst can leak or fail catastrophically. Gypsum karst problems can be mitigated by careful surveying and scientific investigation followed by phased preventive planning, ground investigation, and construction incorporating sinkhole-proof designs. Towns and cities, including parts of Paris (France), Dzerzhinksk (Russia), Madrid and Zaragoza (Spain), Birzai (Lithuania), and Ripon and Darlington (UK), are developed on such ground requiring local planning guidelines and special construction methods. Roads, railways, pipelines, and bridges are particularly vulnerable to such subsidence and require special consideration. Document type: Part of book or chapter of book

Abstract

The nature and distribution of residual stresses are invariably critical for fatigue life with dissimilar material joints often inducing high tensile residual stresses. A fatigue-resistant concept of weld cladding process pipelines, producing compressive residual stresses, is under investigation to examine how these stresses may be influenced. Simplified weld cladding simulations have successfully illustrated the development and distribution of residual stresses through the joint. The study has highlighted the importance of accurate material data for clad and substrate materials with current analysis assumptions in a simple thick-walled pipe discussed. Experimental validation, using ICHD, measured residual stresses with depth on weld clad specimens, resulting in good correlation between simulation and experiment for a nickel-chromium-based superalloy clad on low alloy carbon steel as discussed. Future work, including a full 3D representation of the cladding process and a comparison of residual stress measurement methods, are also discussed. Document type: Part of book or chapter of book

Abstract

Abstract: Mathematical models may be used for design or evaluation of cathodic protection (CP) systems. This chapter provides a historical perspective and a mathematical framework for the development of such models. The mathematical description accounts for calculation of both on- and off-potentials at arbitrarily located surfaces, thus making this approach attractive for simulation of external corrosion direct assessment (ECDA) methods. The approach also allows simulation of independent CP systems. Application of the model is presented for three cases: (a) enhancing interpretation of ECDA results in terms of the condition of the buried pipe; (b) simulating the detrimental influences of competing rectifier settings for crossing pipes protected by independent CP systems (e.g., rectifier wars); and (c) simulating the influence of coatings and coating holidays on the CP of above-ground tank bottoms. Document type: Part of book or chapter of book

Abstract

Establishes the performance, design development, and test requirements for the Special Protective Coating. The system engineering approach was used to develop this document in accordance with the guidelines laid out in the Systems Engineering Management Plan for Project W-314. Document type: Report

Abstract

The main objective of the study is as follows: Identify steel compositions/microstructures suitable for construction of new pipeline infrastructure and evaluate the potential use of the existing steel pipeline infrastructure in high pressure gaseous hydrogen applications. The microstructures of four pipeline steels were characterized and tensile testing was conducted in gaseous hydrogen and helium at pressures of 5.5 MPa (800 psi), 11 MPa (1600 psi) and 20.7 MPa (3000 psi). Based on reduction of area, two of the four steels that performed the best across the pressure range were selected for evaluation of fracture and fatigue performance in gaseous hydrogen at 5.5 MPa (800 psi) and 20.7 MPa (3000 psi). The basic format for this phase of the study is as follows: Microstructural characterization of volume fraction of phases in each alloy; Tensile testing of all four alloys in He and H{sub 2} at 5.5 MPa (800 psi), 11 MPa (1600 psi), and 20.7 MPa (3000 psi). RA performance was used to choose the two best performers for further mechanical property evaluation; Fracture testing (ASTM E1820) of two best tensile test performers in H{sub 2} at 5.5 MPa (800 psi) and 20.7 MPa (3000 psi); Fatigue testing (ASTM E647) ofmore » two best tensile test performers in H2 at 5.5 MPa (800 psi) and 20.7 MPa (3000 psi) with frequency =1.0 Hz and R-ratio=0.5 and 0.1.« le Document type: Report

Abstract

Aqueous radioactive wastes from Savannah River Site (SRS) separations processes are contained in large underground carbon steel tanks. Inspections made during 1993 to evaluate these vessels, and evaluations based on data accrued by inspections made since the tanks were constructed, are the subject of this report. The 1993 inspection program revealed that the condition of the Savannah River Site waste tanks had not changed significantly from that reported in the previous annual report. No new leaksites were observed. No evidence of corrosion or materials degradation was observed in the waste tanks. However, degradation was observed on covers of the concrete encasements for the out-of-service transfer lines to Tanks 1 through 8. Document type: Report

Abstract

This report provides an estimate of the leak rate from the emergency pump well in L-basin that is to be expected during an off-normal event. This estimate is based on expected shrinkage of the engineered grout (i.e., controlled low strength material) used to fill the emergency pump well and the header pipes that provide the dominant leak path from the basin to the lower levels of the L-Area Complex. The estimate will be used to provide input into the operating safety basis to ensure that the water level in the basin will remain above a certain minimum level. The minimum basin water level is specified to ensure adequate shielding for personnel and maintain the ''as low as reasonably achievable'' concept of radiological exposure. The need for the leak rate estimation is the existence of a gap between the fill material and the header pipes, which penetrate the basin wall and would be the primary leak path in the event of a breach in those pipes. The gap between the pipe and fill material was estimated based on a full scale demonstration pour that was performed and examined. Leak tests were performed on full scale pipes as a part of thismore » examination. Leak rates were measured to be on the order of 0.01 gallons/minute for completely filled pipe (vertically positioned) and 0.25 gallons/minute for partially filled pipe (horizontally positioned). This measurement was for water at 16 feet head pressure and with minimal corrosion or biofilm present. The effect of the grout fill on the inside surface biofilm of the pipes is the subject of a previous memorandum.« le Document type: Report