Non-Destructive Evaluation of RPV Embrittlement by Means of the Thermoelectric Power Method

2020 ◽  
Author(s):  
M. Niffenegger ◽  
D. F. Mora ◽  
H. Kottmann
Keyword(s):  
Thermoelectric Power ◽  
Power Method ◽  
Dislocation Loops ◽  
The Finite Element Method ◽  
Magnetic Barkhausen Noise ◽  
Charpy Test ◽  
Ultrasonic Scattering ◽  
Paul Scherrer ◽  
Non Destructive ◽  
Surveillance Specimens

Abstract Nondestructive evaluation (NDE) methods are widely used for inspecting safety relevant components in nuclear reactors. Most of these NDE-methods are optimized and applied for the detection of cracks but there is still no reliable NDE method for measuring the embrittlement of RPV steels. However, since the evaluation of RPV embrittlement of so-called Surveillance specimens with the Charpy test is a destructive approach, NDE methods are highly required. Among the investigated technics are acoustic (Ultrasonic scattering), electric (resistivity, thermoelectric) and magnetic (Barkhausen Noise, Non-Linear Harmonics Analysis, Micromagnetic Multiparameter) methods. However, all the methods under investigation suffer from the fact that fracture toughness of steel depends upon several factors, especially on lattice defects such as vacancies, dissolved atoms, dislocation loops, solute clusters, precipitates and dislocations. A major obstacle to the application of NDE methods for the quantification of material embrittlement is that they may be not only sensitive to these defects but also to other factors, such as magnetic, acoustic and electrical properties, as well as to surface quality and ambient temperature, etc.). In this paper, we present results gained by the optimization and application of the thermoelectric power method (TEPM) at the Paul Scherrer Institut (PSI) in Switzerland. The TEPM uses the change of the Seebeck coefficient (K) as an indicator for the material embrittlement. A clear almost linear correlation between the shift of the Nil-Ductile-Transition-Temperature (NDTT) and the change of the K was found. Beside the TEPM and its optimization with the finite element method, we describe the influencing parameters and the potential of this promising NDE method.

Highlights in the history of X-ray topography1

1995 ◽  
Vol 210 (6) ◽  
Author(s):  
A. R. Lang
Keyword(s):  
Magnetic Domain ◽  
Diffraction Theory ◽  
Dislocation Loops ◽  
X Ray Diffraction ◽  
X Ray ◽  
Domain Structures ◽  
Structure Factors ◽  
History Of ◽  
Dislocation Sources ◽  
Non Destructive

AbstractX-ray topography provides a non-destructive method of mapping point-by-point variations in orientation and reflecting power within crystals. The discovery, made by several workers independently, that in nearly perfect crystals it was possible to detect individual dislocations by X-ray diffraction contrast started an epoch of rapid exploitation of X-ray topography as a new, general method for assessing crystal perfection. Another discovery, that of X-ray Pendellösung, led to important theoretical developments in X-ray diffraction theory and to a new and precise method for measuring structure factors on an absolute scale. Other highlights picked out for mention are studies of Frank-Read dislocation sources, the discovery of long dislocation helices and lines of coaxial dislocation loops in aluminium, of internal magnetic domain structures in Fe-3 wt.% Si, and of stacking faults in silicon and natural diamonds.

Design of controllable units for mechanical transmissions

2021 ◽  
pp. 22-26
Author(s):  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Simulation Modeling ◽  
Mechanical Transmission ◽  
Non Destructive Testing ◽  
The Finite Element Method ◽  
Destructive Testing ◽  
Bench Tests ◽  
Non Destructive ◽  
Element Method

The scientific and methodological foundations of the design of mechanical transmission units of transport and technological machines, adapted for diagnosing the operability by thermometry parameters, based on the results of bench tests and simulation modeling by the finite element method, are considered. An algorithm is developed for the design testing of power units for adaptability to thermometric non-destructive testing. Keywords: design, controllability, diagnostics, thermometry, finite element method [email protected]

scholarly journals Dislocation loops as a mechanism for thermoelectric power factor enhancement in silicon nano-layers

2016 ◽  
Vol 109 (17) ◽  
pp. 173905 ◽  
Author(s):  
Nick S. Bennett ◽  
Daragh Byrne ◽  
Aidan Cowley ◽  
Neophytos Neophytou
Keyword(s):  
Thermoelectric Power ◽  
Power Factor ◽  
Dislocation Loops ◽  
Thermoelectric Power Factor

Fatigue damage in bending of reinforced concrete frames using non-destructive tests for dynamic strength of the cylinder

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Dragan D. Milašinović ◽  
Aleksandar Landović ◽  
Danica Goleš
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Fatigue Damage ◽  
Cross Section ◽  
Modal Parameters ◽  
The Finite Element Method ◽  
Concrete Frames ◽  
Content Type ◽  
Non Destructive

PurposeThe purpose of this paper is to contribute to the solution of the fatigue damage problem of reinforced concrete frames in bending.Design/methodology/approachThe problem of fatigue damage is formulated based on the rheological–dynamical analogy, including a scalar damage variable to address the reduction of stiffness in strain softening. The modal analysis is used by the finite element method for the determination of modal parameters and resonance stability of the selected frame cross-section. The objectivity of the presented method is verified by numerical examples, predicting the ductility in bending of the frame whose basic mechanical properties were obtained by non-destructive testing systems.FindingsThe modal analysis in the frame of the finite element method is suitable for the determination of modal parameters and resonance stability of the selected frame cross-section. It is recommended that the modulus of elasticity be determined by non-destructive methods, e.g. from the acoustic response.Originality/valueThe paper presents a novel method of solving the ductility in bending taking into account both the creep coefficient and the aging coefficient. The rheological-dynamical analogy (RDA) method uses the resonant method to find material properties. The characterization of the structural damping via the damping ratio is original and effective.

scholarly journals Dielectric-Filled Reentrant Cavity Resonator as a Low-Intensity Proton Beam Diagnostic

Instruments ◽  
2018 ◽  
Vol 2 (4) ◽  
pp. 24 ◽  
Author(s):  
Sudharsan Srinivasan ◽  
Pierre-André Duperrex
Keyword(s):  
Resonance Frequency ◽  
Proton Beam ◽  
Second Harmonic ◽  
Cavity Resonator ◽  
Beam Current ◽  
Dielectric Thickness ◽  
Medical Treatment Facility ◽  
Beam Currents ◽  
Paul Scherrer ◽  
Non Destructive

Measurement of the proton beam current (0.1–40 nA) at the medical treatment facility PROSCAN at the Paul Scherrer Institut (PSI) is performed with ionization chambers. To mitigate the scattering issues and to preserve the quality of the beam delivered to the patients, a non-interceptive monitor based on the principle of a reentrant cavity resonator has been built. The resonator with a fundamental resonance frequency of 145.7 MHz was matched to the second harmonic of the pulse repetition rate (72.85 MHz) of the beam extracted from the cyclotron. This was realized with the help of ANSYS HFSS (High Frequency Structural Simulator) for network analysis. Both, the pickup position and dielectric thickness were optimized. The prototype was characterized with a stand-alone test bench. There is good agreement between the simulated and measured parameters. The observed deviation in the resonance frequency is attributed to the frequency dependent dielectric loss tangent. Hence, the dielectric had to be resized to tune the resonator to the design resonance frequency. The measured sensitivity performances were in agreement with the expectations. We conclude that the dielectric reentrant cavity resonator is a promising candidate for measuring low proton beam currents in a non-destructive manner.

scholarly journals Study of Residual Stresses and Microstructural Changes in Charpy Test Specimens Reconstituted by Various Welding Techniques

Metals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 632 ◽  
Author(s):  
Gizo Bokuchava ◽  
Peter Petrov
Keyword(s):  
Residual Stress ◽  
Laser Beam Welding ◽  
Diffraction Method ◽  
Charpy Impact ◽  
Stress Distributions ◽  
Charpy Test ◽  
Microstructural Changes ◽  
Surveillance Specimens ◽  
Weld Seams ◽  
Reactor Pressure

Changes in the reactor pressure vessel (RPV) material properties due to neutron irradiation are monitored by means of surveillance specimen programs, which are used for realistic evaluation of the RPVs’ lifetime. Due to a limited number of surveillance specimens, the evaluation of reconstitution methods by various welding techniques after Charpy impact tests is of great importance. Time-of-flight (TOF) neutron diffraction method was used to determine the residual stress distributions and microstructural changes in Charpy specimens welded by arc stud, electron, and laser beam welding techniques. The lowest level of the residual stress in weld seams regions was found for the specimen welded by electron beam with optimal parameters as compared to other techniques. At the same time, this specimen exhibits the maximal level of microstrain, which points to high dislocation density in the material. The corresponding contributions to the yield strength due to various strengthening mechanisms were estimated.

Testing of Hardness on Long Rail Welded Joint by Means of Magnetic Barkhausen Noise Technique

2014 ◽  
Vol 490-491 ◽  
pp. 351-357
Author(s):  
Liang Yin ◽  
Di Shu ◽  
Juan Chen ◽  
Xin Qi
Keyword(s):  
Welded Joint ◽  
Brinell Hardness ◽  
Surface Hardness ◽  
Barkhausen Noise ◽  
Non Destructive Testing ◽  
Magnetic Barkhausen Noise ◽  
Destructive Testing ◽  
Testing Technique ◽  
Non Destructive ◽  
Microstructure Of The Material

The experiment shows that the Magnetic Barkhausen Noise (MBN) signal strongly depends on the elastic deformation, heat treatment state of surface and microstructure of the material, etc. Using the MBN technology that rely on the material characteristics, MBN can be used for testing the surface hardness of 60kg/m U74 seamless rail made by China Harbin welded rail plant. And the testing result obtained by the MBN method is consistent with the results obtained by the Brinell hardness (HB) method. Consequently, this non-destructive testing technique will have a strong life and an extensive market.

scholarly journals Optimisation of amplitude distribution of magnetic Barkhausen noise

2017 ◽  
Vol 68 (5) ◽  
pp. 384-389
Author(s):  
Jozef Pal’a ◽  
Vladimír Jančárik
Keyword(s):  
Measurement Method ◽  
Measurement Accuracy ◽  
Amplitude Distribution ◽  
Barkhausen Noise ◽  
Significant Issue ◽  
Magnetic Barkhausen Noise ◽  
Non Destructive Evaluation ◽  
Treatment Conditions ◽  
Lift Off ◽  
Non Destructive

Abstract The magnetic Barkhausen noise (MBN) measurement method is a widely used non-destructive evaluation technique used for inspection of ferromagnetic materials. Besides other influences, the excitation yoke lift-off is a significant issue of this method deteriorating the measurement accuracy. In this paper, the lift-off effect is analysed mainly on grain oriented Fe-3%Si steel subjected to various heat treatment conditions. Based on investigation of relationship between the amplitude distribution of MBN and lift-off, an approach to suppress the lift-off effect is proposed. Proposed approach utilizes the digital feedback optimising the measurement based on the amplitude distribution of MBN. The results demonstrated that the approach can highly suppress the lift-off effect up to 2 mm.

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