Radioisotopes as radiotracers are used for leak and blockage detection in buried pipelines and for determining residence time distribution and flow dynamics and other applications..
Internal on-line leakage testing is carried out by injecting a radioactive tracer into the process stream from which the leakage is suspected and presence of the tracer in adjacent stream or in the environment is monitored.
The technique finds application in leak detection in underground pipelines, cross country pipelines, industrial systems, heat exchangers, valves, flares, boilers.... etc.
Residence time distribution (RTD) analysis using radiotracers can be used to gain better understanding of flow dynamics inside a vessel.
RTD analysis provides valuable diagnostic data on plant malfunctioning, such as:
Depth of navigation channels in ports and harbours is maintained by dredging sediment and dumping at suitable locations. Radiotracers help in selecting suitable dumping sites at optimum distances.
After selecting suitable dumping site, the dredger travels less, thereby reducing the expenses by crores of rupees per year.
If any water loss is there due to leakage, the flow lines will be formed in the direction of leak. Ionised radioactive gold from the injected gold solution travels through these flow lines and gets easily adsorbed on the soil matrix at the leakage spot. Using underwater radiation detector the exact location of the spot at which gold has got adsorbed can be identified. BRIT helped NIH, Roorkee to pinpoint the location of leakage of water at a dam near Chandigarh using Au-198 as radiotracer.
During the secondary recovery of oil, to study the flow dynamics of injected water i.e. direction of injected water flow, residence time/ breakthrough time estimation, flow pattern, etc. radiotracers are used.
For this purpose a suitable radiotracer is injected in a water injection well. Samples are collected from the surrounding production wells in the reservoir. The samples are analyzed after pretreatment in auto-liquid scintillation counter. The results are interpreted to decide the reservoir characteristics and the water movement in the reservoir.