محسن شریف زاده

Pigging is one of the conventional processes in the oil and gas industries, which is done in order to remove sediments from pipelines and also perform some non-destructive tests. On the other hand, due to various branches in the main pipeline, there is a possibility of stopping the pig. The right solution is to use mesh caps that not only prevent the pig from getting stuck, but also guarantee the passage of flow through all the main and secondary lines. According to the opinions of technical inspectors, there is no comprehensive information about the presence/absence of these caps in a large number of branches. The industrial radiography lacks the ability to detect the presence and absence of the cap in a fully filled pipe due to the average energy of the emitted beam and its geometrical structure. It is focused on the conceptual design of the nuclear system for investigating the possibility of pigging in the location of pipeline branches in the Monte Carlo environment. Ultimately, the results show the fact that in the situation where the source and the detector are perpendicular to the axis of the main and secondary branches and facing each other, the maximum counting sensitivity and discrimination can be achieved. Moreover, the relative difference of two states with and without the presence of metal grid for two states of filling the pipe with air and oil is equal to 53.8% and 57.1%, respectively.

Ensuring flow with the increasing need to extract oil and gas from reservoirs is known as a big challenge, and in the meantime, scale deposition in pipelines is a major problem. Since scale deposition occurs in a short time, it is especially important to control and predict it in pipelines as soon as possible. There are several methods for predicting the deposition pattern and measuring its thickness. The gamma transmission method is a non-destructive method for this task. The application of this technique requires optimal placement of the detectors and radioactive source around the pipe so that the measurement can be made with maximum accuracy in a short time. The cost, the ability to deploy the instrument at various positions on the platform and underwater, and minimization of absorbed dose to the operator are other important goals that should be considered. In this study, using the geometric analysis and Monte Carlo simulation, it is shown that the fan-shaped arrangement of the detectors with certain spacing around the pipe can lead to an optimal measurement of the deposition regime and the scale thickness.

In this paper, by using Monte Carlo simulation of MCNPX software, the design and optimization of the dimensions and distances between the plastic scintillation detectors used in the gamma ray portal monitor in order to build based on these optimized dimensions It can be. The test and performance evaluation steps of the gamma ray portal monitor based on the radiation acceptance test section of the International Electrotechnical Commission standard No. IEC 62244:2024 including the false alarm test, the background effects test (on the performance of the detectors), the gamma radiation detection test and the out-of-range response test is accepted. The results of the conducted evaluation tests confirm the compliance of this portal monitor with the IEC 62244 standard. Based on this, it can be concluded that the design, simulation and placement of the detectors have been done with sufficient accuracy and are approved. Also, the minimum detectable activity of the device for the 60Co source was equal to 0.7 microcurie activity and for the 137Cs source equal to 1.5 microcurie activity at 1 meter with a discrimination level of ±2.7σ, which is comparable to the available commercial monitors.

One of the important steps in the nuclear fuel cycle is uranium enrichment. It is essential to carry out control processes using continuous measurement on the way to uranium with the desired enrichment of the facility. On the other hand, due to being in the environment with high external radiation and also suitable for internal exposure of the operator, especially when working with uranium powder, it is necessary to use accurate instruments with the ability to monitor online and continuously, which is a special place in the nuclear instrumentation. In this work, we decided to work on a conceptual design of the enrichment and weight measurement system for uranium tetrafluoride powder into loading and handling tanks in the nuclear industry. For this purpose, with the aim of reducing costs while eliminating maximum counting error, focus on reading only gamma rays emitted from powder or with radioactive lateral source was considered. The design was based on geometric location optimization of scintillating detector/detectors around the tank containing uranium tetrafluoride powder in order to have maximum accuracy in measurement. The simulation results in Monte Carlo software show that for different enrichment percentages and also different heights of uranium powder inside the cylindrical tank, we are able to have maximum accuracy in measuring two parameters of richness percentage and powder weight at specific angles.

The acquisition of knowledge and the continued development of cosmic ray detection technology has led to new connections between academic disciplines such as physics, geology, agriculture, mining and archaeology. Because of the interaction of these beams with the Earth's atmosphere, a massive flux of secondary particles is produced and collided with the Earth. As one of these energetic charged particles, the muons are capable of penetrating large surface and deep earth structures, which provides a new tool in surface/subsuface mapping. Due to the density dependent interaction of these charged particles with matter, it is possible to image various surface structures such as volcanoes, antiquities and civil structures or reservoirs, cavities, radioactive wastes and subsurface valuable mineral veins. The aim of this paper is to review the recent years of research on this new technique called muography and it was tried here in a new structure to use this technique in all three fields of mapping, surveying and remote sensing to extract information about large surface/subsurface volumes.

In the process of extracting gas and condensate from the seabed, we often encounter a multiphase flow. Multiphase fluid flow to pass through the transmission pipes requires the separation of outgoing water from the formation on offshore platforms in order to eliminate corrosion effects in downstream facilities such as refinery. Formation water often enters the sea after separation. Water monitoring of the formation in terms of salinity is an important part of the process of measuring the volumetric rate of multiphase flow components at the separator site by single-phase metering systems. Considering the high dependence of parameters such as density, viscosity and electrical conductivity of fluid to salinity level, we decided to investigate the possibility of conceptual design of formation water salinity system based on gamma technique. The change in the key characteristics related to the gamma beam shaping module emitted from the cobalt-60 radioactive source and with the consideration of radiation safety of personnel, it was obtained the optimum geometric and dimensional conditions of the collimator in order to achieve maximum accuracy in different amounts of salinity fraction of sodium iodide salt in water measurement.

Distance measuring between two metal plates by γ-ray backscattering is a new method that is applicable for different industries, especially the oil, gas, and petrochemical industry. In the present work, 2, 6, and 10 mm thick steel plates were used as thin, medium, and thick plates to perform the experiments. Also, two sources of 137Cs and 60Co have been used to show the effect of source energy on the accuracy of the measurements. The results showed that the distance measurement depends on the Gamma-ray energy, and for the same measurement accuracy, the Gamma source with higher energy would be more applicable for measuring the distance between two steel plates. Moreover, it was found that increasing the γ-ray energy will increase the accuracy of the measurement. In addition to the energy of the gamma source, the distance measurement depends on the thickness of the two plates, the arrangement of the thicker plate comparing to the thinner ones, and the distance between them. Finally, increasing the distance between the plates leads to reducing the measurement accuracy, which was calculated to be one centimeter.

When there is limitation access to one side of the structure in industry, one of the best methods for thickness measurements is the Compton scattering. In this paper, due to the statistical behavior of dispersed beam counting, we discuss the accuracy of the measurement for steel thickness. Using the experimental method and comparing it with MCNP simulation code, the accuracy is obtained less than 0.2 mm.

Multiphase flow metering, has been one of the most important issues in oil/gas industry, since the early 80s. Oil-water two-phase flow, shows off specially in flow meters that work based on separation of oil-water-gas three-phase flow into liquid (oil-water), and gas streams just before measurement. Here, at first, two-phase flow homogenizer loop (TPFHL) as a solid-liquid as well as liquid-liquid homogenizer loop, is introduced, and then its performance accuracy is verified by counting the transmitted gamma-rays of a 137Cs radioactive source. The acceptable results, compared to the reference data, endorse the capability of the introduced loop in conjunction with the gamma densitometer for volume fraction measurement in a wide range of two-phase mixtures. Moreover, the instrumentation usage for oil-water component fraction measurement was simulated, using an 241Am gamma source which showed a good agreement with the authentically published results.