Pressure Vessel Monitoring Research Articles

Laser micro-fabricated multifunctional sensing layer for structural health monitoring

Multifunctional sensing layer (MSL) integrated with multiple sensors and transducers has diverse applications in structural health monitoring (SHM). However, current MSLs still suffer from using rigid sensing units and complicated fabrication methods. To address this, a type of MSL integrated with flexible multi-functional sensing units and stretchable interconnectors was developed in this study by a laser-microfabrication (LMF) method with high efficiency and scalability. The flexible strain sensor has a sensitivity of 8.5, a minimum detection limit of 0.01%, and a durability of up to 12 000 cycles. The flexible temperature sensor has a temperature coefficient of resistance up to 2.75 × 10−3 °C–1 and a response time of 2.5 s. The flexible comb transducer provides a damage detection accuracy of over 90%. Further investigation proves the capability of the MSL for real-time monitoring of pressure vessels. The high efficiency and scalability of the LMF as well as the multi-functional sensing ability pave the potential application of the MSL in SHM.

A 3D leakage monitoring method for pressure vessel based on region segmentation and time difference estimation

Leak monitoring and location technology is an important guarantee for the safety of pressure vessels. However, the first-time capture of sudden leakage incidents and the structure of the revolving body have brought challenges to the full range of pressure vessel monitoring and location. In this paper, based on the structural characteristics of the cylindrical pressure vessel, a 3D monitoring and location method based on region segmentation and time difference estimation is proposed, which combines regional location and time difference location to improve the location speed and accuracy of the algorithm. The adaptive threshold is adopted to capture the first moment of leakage, and the regional cross-correlation calculation is used to locate the leakage source in the area. The performance of the method is verified by liquid leakage experiment based on distributed acoustic emission sensor. The results show that the proposed method has good adaptability. It can capture leakage events and locate the leakage events at different positions and apertures in the first time, with an average location error of 2.44 cm. This study will have a new understanding of the location technology of pressure vessels and provide a reference for the health monitoring of large pressure vessels.

Detection of parallel double crack in pressure vessel based on optical fibre ultrasonic sensing

In pressure vessels, cracks often do not appear singly, and current pure ultrasonic testing cannot meet the needs of online monitoring of pressure vessels. Based on the ultrasonic reflection method, the relationship between the axial spacing and circumferential spacing between two parallel cracks, the time of the peak voltage signal, and the peak voltage and amplitude are discussed. Based on the experiment, the interacting region between the two parallel cracks with length, width, and depth of 10, 1, and 4 mm, respectively, was determined.

Research of a Novel Ultra-High Pressure Sensor with High-Temperature Resistance.

Ultra-high pressure measurement has significant applications in various fields such as high pressure synthesis of new materials and ultra-high pressure vessel monitoring. This paper proposes a novel ultra-high pressure sensor combining a truncated-cone structure and a silicon-on-insulator (SOI) piezoresistive element for measuring the pressure up to 1.6 GPa. The truncated-cone structure attenuates the measured pressure to a level that can be detected by the SOI piezoresistive element. Four piezoresistors of the SOI piezoresistive element are placed along specific crystal orientation and configured as a Wheatstone bridge to obtain voltage signals. The sensor has an advantage of high-temperature resistance, in that the structure of the piezoresistive element can avoid the leakage current at high temperature and the truncated-cone structure separates the piezoresistive element from the heat environment. Furthermore, the upper surface diameter of the truncated-cone structure is designed to be 2 mm for the application of small scale. The results of static calibration show that the sensor exhibits a good performance in hysteresis and repeatability. The temperature experiment indicates that the sensor can work steadily at high temperature. This study would provide a better insight to the research of ultra-high pressure sensors with larger range and smaller size.

Research of Key Technology for Macroscopic Hydrogen Induced Injury Testing and In-Service Monitoring of Pressure Vessel in Wet Hydrogen Sulfide Environment

The hydrogen induced injury detection and propagation monitoring of pressure vessels serviced in wet hydrogen sulfide environment is one of problems needs to be solved urgently for petrochemical device long-term operation. According to the key technology and difficulties of macroscopic hydrogen induced injury testing and in-service monitoring of pressure vessels in wet hydrogen sulfide environment, multiple ultrasonic nondestructive testing technologies were used. In order to realize rapid detection for macroscopic hydrogen induced injury of large area, electromagnetic ultrasonic technologies were used to test the pressure vessel cutting board, and ultrasonic guided wave technique was used to research the HB artificial simulated test plate by simulation and testing; Ultrasonic phased array was used to measure defects accurately for pressure vessels which have hydrogen induced injury; The electromagnetic ultrasonic technology was used to study its in-service monitoring, and the expansion situation caused by macroscopic hydrogen induced injury was monitored; It were provided foundation for hydrogen induced injury diagnosis and safety evaluation after FFS evaluation by study and application of these detection techniques.

On-line Monitoring of Engineering Components Using Acoustic Emission Technique

Acoustic emission technique (AET) has been used for on-line monitoring of pressure vessels with artificial defects in the laboratory and for monitoring structural integrity of storage vessels in heavy water plant. The laboratory studies are helpful for getting better insight into the deformation and fracture aspects in the vessels, towards better utilisation of AET for structural integrity of components. AE results generated during hydrotesting of the storage vessels were used to confirm the structural integrity of the vessels. AE was used to monitor compression loading of plain and fly ash concrete. This showed three stages due to crack closure/microcracking, steady crack propagation and unstable crack propagation. An attempt was made to compare the types of cracking in concrete using AE parameters.

Accurate Determination and Benchmarking of Radiation Field Parameters, Relevant for Pressure Vessel Monitoring—Review of Some REDOS Project Results

Abstract Plant life management needs a reliable estimation of radiation field parameters, including their uncertainty, to avoid the use of conservative approaches. The particular objectives of the REDOS project [1] are the improvements of the RPV monitoring, the improvement of the neutron-gamma calculation methodologies through the LR-0 engineering benchmarks for WWER-1000 and WWER-440, and the accurate determination of radiation field parameters in the vicinity and over the thickness of the RPV. This paper is mainly devoted to the comparison and analysis of the experimental and calculated LR-0 data. The LR-0 benchmark data consist of neutron spectra (WWER-440 Mock-ups) and neutron + photon spectra (WWER-1000 Mock-up) in several points from the barrel simulator to the outer surface of RPV and evaluated integral fluxes, space-energy indices, like the spectral indices and attenuation factors in measuring points.

Measurement and calculation of the fast-neutron and photon spectra from the core boundary to the biological shielding in the WWER-1000 reactor model

The fast-neutron and photon space-energy distributions have been measured in an axially (1.25 m active height) and azimuthally (60 degree symmetry sector) shortened model of the WWER-1000 reactor assembled in the LR-0 experimental reactor. The space-energy distributions have been calculated with the stochastic code MCNP and the deterministic three-dimensional code TORT. Selected results are presented and discussed in the paper. This work has been done in the frame of the EU 5th FW project REDOS REDOS, Reactor Dosimetry: Accurate determination and benchmarking of radiation field parameters, relevant for reactor pressure vessel monitoring. EURATOM Programme, Call 2000/C 294/04). All geometry and material composition data of the model as well as the available experimental data were carefully checked and revised.

Acoustic emission monitoring of pressure vessels

This paper summarises the main features of the acoustic emission testing method. A short overview is given of how common failures can be detected at pressure vessel testing and how measurement results are evaluated. Acoustic emission monitoring of pressure vessels for the power plant industry has been introduced also in Hungary: an overview is given and some of the measurement results are presented.

An assessment of acoustic emission for nuclear pressure vessel monitoring

Recent research has greatly improved our understanding of the basic mechanisms of deformation and fracture that generate detectable acoustic emission signals in structural steels. A critical review of the application of acoustic emission (AE) to the fabrication, proof testing and in-service monitoring of nuclear pressure vessels is presented in the light of this improved understanding. The detectability of deformation and fracture processes in pressure vessel steels is discussed, and recommendations made for improving source location accuracy and the development of quantitative source assessment techniques. Published data suggest that AE can make an important contribution to weld fabrication monitoring, and to the detection of defects in lower toughness materials during vessel proof testing. In high toughness materials, however, the signals generated during ductile crack growth may frequently be too weak for reliable detection. The feasibility of AE for continuous monitoring has not yet been adequately demonstrated because of high background noise levels and uncertainty about AE signal strengths from the defect growth processes that occur in service. In-service leak detection by AE shows considerable promise. It is recommended that further tests are carried out with realistic defects, and under realistic conditions of loading (including thermal shock and fatigue) and of environment.