Depicting corrosion-born defects in pipelines with combined neutron/γ ray backscatter: a biomimetic approach

Abstract

The identification of corrosion, cracks and defects in pipelines used for transporting oil and gas can reduce the possibility of leaks, and consequently, it can limit the extent of an environmental disaster, public hazard and the associated financial impact of such events. Typically, corrosion in oil pipelines is measured with non-destructive ultrasonic or electromagnetic techniques, on the basis that corrosion and defects are often manifest as a change of thickness in the steel from which pipelines are made. However, such approaches are not practical for underground pipelines and their deployment can be complicated for the case of pipelines covered by insulation. in this paper, we present an innovative, non-destructive testing technique, which exploits the backscatter of a combination of fast-neutron and γ radiation from steel samples of a variety of thicknesses consistent with changes that might arise due to corrosion of a pipe wall. our research demonstrates the potential to measure and characterise different steel thicknesses by detecting both the elastic, fast-neutron backscatter and the Comptonscattered γ radiations, simultaneously. further, we demonstrate that the presence of insulation yields a consistent and separable influence on the experimental, wall-thickness measurements. The data from experimental measurements are supported by a comprehensive Monte carlo computer simulation study.The processes by which mechanical and electromagnetic waves are reflected by materials, are phenomena exploited by a variety of animal species for orientation, to procure food and for a great diversity of other purposes. A biomimetic relationship exists in this regard between the natural world and technological human achievements, exemplified on the one hand by the reliance of some species of mammals (predominantly bats) on ultrasound, with which to hunt, avoid predators and even to classify different types of plants 1-5 , and on the other by sonar 6 . The latter is central to a wide variety of non-destructive, industrial assessment techniques and a related international industry, such as the measurement of distance, density, porosity and imaging. Similar analogies exist for the case of reflected electromagnetic waves, e.g., sight, radar 7 etc.Amongst the first observations of the scattering of particles are those of Rutherford in his famous gold foil experiments (1908)(1909)(1910)(1911)(1912)(1913). At the atomic scale, the reflections of waves and particles approach one another phenomenologically, and offer one of the founding scientific observations supporting wave-particle duality. In this regard, neutron scattering and its applications are perhaps amongst the most remarkable and tangible exemplars of quantum-mechanics. As to whether a scattering process is elastic or inelastic is inferred by the corresponding isotopic cross section, calculated on the basis of neutrons affording properties of complex plane waves. Below the MeV range in energy, the radiation wavelength is much greater than the range of the strong nuclea...

Prompt gamma-ray methods for industrial process evaluation: A simulation study

“…The system consists of a neutron gauge and gamma measurement device that uses 137 Cs. Another study proposed the deployment of both neutrons and gamma-ray of 252 Cf by simultaneously measuring the backscatter of the two types of radiation to detect corrosion defects in pipelines [26].…”

Fast neutron and γ-ray backscatter radiography for the characterization of corrosion-born defects in oil pipelines

“…These measurements can be taken as a basis to develop an imaging technique, for instance, radiography or tomography, since the measured backscattered counting rate can be converted, as per analogy with the common transmission imaging, in an image contrast index. With this technique, both neutrons and  rays can be exploited simultaneously and merged with each other, as done in previous research [4,5] for transmission tomography.…”

“…Top: experimental results of the neutron (left) and -ray (right) backscattered flux for bare steel, steel and polyethylene insulation, and steel and concrete insulation. Bottom: MCNP6 Monte Carlo simulation results of backscatter flux, as a function of the steel thickness, for bare steel, steel and polyethylene insulation, and steel and concrete insulation[5].…”

Simultaneous, Robot-Compatible γ-Ray Spectroscopy and Imaging of an Operating Nuclear Reactor

“…The radiation detection analysis hardware utilised for this research is a quad-channel Mixed Field Analyser (MFA, Hybrid Instruments Ltd., UK) [12]. It provides 12-bit sampling resolution at a rate of 500 MSa/s, and has neutron-γ discrimination and spectroscopic capabilities, as well as Transistor-Transistor-Logic (TTL) outputs for counting purposes [13], [14]. For this application, part of this commercial hardware has been ported into a bespoke enclosure to contain the instrumentation's electronics, with passive cooling and 12 V DC power supply.…”