LEAK DETECTION BY ACOUSTIC EMISSION MONITORING

PHASE I WILL PROVE THE FEASIBILITY OF RELIABLE, ROBUST DETECTION OF GAS OR LIQUID LEAKS IN UNDERGROUND STORAGE TANKS AND PIPELINES, UTILIZING ACOUSTIC EMISSION MONITORING (AEM) TECHNIQUES, SUCH AS PRODUCT ARRAY PROCESSING AND FOURIER SPECTRUM PROCESSING. THE REQUIRED DETECTION THRESHOLD OF THE AEM PROCESSOR, FOR A GIVEN PROBABILITY OF DETECTION AND FALSE ALARM RATE, AND THE ACCELEROMETER SENSITIVITY WILL BE DEFINED FOR VARIOUS LIQUIDS, FUEL TANK AND PIPELINE MATERIAL, SOIL CHARACTERISTICS AND LEAK RATES. THE SPECIFICATION OF THE ACCELEROMETER ELEMENT, THE COUPLING OF THE ACCELEROMETER TO THE GROUND, AND THE ARRAY SPATIAL PROCESSING GAIN WILL BE STUDIED TO ACHIEVE RELIABLE DETECTION FOR A LOW LEAK RATE (LESS THAN 0.01 GAL/HR) AT NOMINAL DEPTH. A TECHNICAL ASSESSMENT WILL BE MADE OF WAVEFORM PEAK AND DIRECTIONAL DEVIATION ESTIMATION UTILIZING A SPLITBEAM CORRELATOR. A TECHNICAL ASSESSMENT WILL BE MADE OF SPECTRAL PEAK AND FREQUENCY ESTIMATION UTILIZING CONVENTIONAL FFT PROCESSING, AND THE UTILIZATION OF CROSS-SPECTRAL ESTIMATES OF EACH SENSOR TO DERIVE DIRECTIONAL INFORMATION. THE PERFORMANCE AND OPERATIONAL PARAMETERS FOR A COST-EFFECTIVE AEM SYSTEM WILL BE SPECIFIED FOR FABRICATION, TESTING, AND EVALUATION IN PHASE II.