The Development of Non Destructive Remote Measurement Method of Concrete Contamination

2013 ◽  
Author(s):  
V. E. Stepanov ◽  
V. N. Potapov ◽  
O. P. Ivanov
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Background Radiation ◽  
Natural Radionuclides ◽  
Remote Measurement ◽  
Sample Analysis ◽  
Accuracy Of Measurements ◽  
Contamination Levels ◽  
Destructive Measurement ◽  
Non Destructive

In the frame of the decommissioning of nuclear power plants or laboratories, the penetration depth of the contamination in concrete surfaces: walls, floor, is unknown. Its knowledge requires sample analysis, that is time consuming and expensive. The main goal of the work is to define and evaluate a non-destructive measurement technique for the evaluation of the contamination depth in concrete. Estimation of accuracy of measurements for different contamination levels, time of measurement, value of natural radionuclides (NRN) concentration in concrete and background radiation dose were carried out. The type of relevant detector depends of selected limiting sensitivity, the weight and sizes of the device.

Human reliability in non-destructive inspections of nuclear power plant components: modeling and analysis

2019 ◽  
Vol 7 (2B) ◽  
Author(s):  
Vanderley Vasconcelos ◽  
Wellington Antonio Soares ◽  
Raissa Oliveira Marques ◽  
Silvério Ferreira Silva Jr ◽  
Amanda Laureano Raso
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Human Factors ◽  
Nuclear Power ◽  
Power Plants ◽  
Failure Modes ◽  
Cooling System ◽  
Human Reliability ◽  
Non Destructive ◽  
Plant Components

Non-destructive inspection (NDI) is one of the key elements in ensuring quality of engineering systems and their safe use. This inspection is a very complex task, during which the inspectors have to rely on their sensory, perceptual, cognitive, and motor skills. It requires high vigilance once it is often carried out on large components, over a long period of time, and in hostile environments and restriction of workplace. A successful NDI requires careful planning, choice of appropriate NDI methods and inspection procedures, as well as qualified and trained inspection personnel. A failure of NDI to detect critical defects in safety-related components of nuclear power plants, for instance, may lead to catastrophic consequences for workers, public and environment. Therefore, ensuring that NDI is reliable and capable of detecting all critical defects is of utmost importance. Despite increased use of automation in NDI, human inspectors, and thus human factors, still play an important role in NDI reliability. Human reliability is the probability of humans conducting specific tasks with satisfactory performance. Many techniques are suitable for modeling and analyzing human reliability in NDI of nuclear power plant components, such as FMEA (Failure Modes and Effects Analysis) and THERP (Technique for Human Error Rate Prediction). An example by using qualitative and quantitative assessesments with these two techniques to improve typical NDI of pipe segments of a core cooling system of a nuclear power plant, through acting on human factors issues, is presented.

Method of Non-Destructive Measurement of Natural Radionuclides Concentration in Building Materials

ANRI ◽  
2021 ◽  
Vol 0 (1) ◽  
pp. 31-44
Author(s):  
Aleksey Vasil'ev ◽  
Aleksey Ekidin ◽  
Mariya Pyshkina ◽  
Georgiy Malinovskiy ◽  
Aleksandra Onischenko ◽  
...  
Keyword(s):  
Gamma Radiation ◽  
Flux Density ◽  
Building Materials ◽  
Specific Activity ◽  
Natural Radionuclides ◽  
Gamma Spectrometer ◽  
Average Activity ◽  
Destructive Measurement ◽  
Non Destructive ◽  
Calculated Flux

A method for non-destructive monitoring of the content of natural radionuclides in building materials has been developed. Spectrum measurements of gamma radiation are carried out with a pre-calibrated field gamma spectrometer. The calculation of the average specific activity of natural radionuclides in building materials is carried out by comparing the calculated flux density of unscattered gamma quanta normalized to the specific activity, and the experimentally measured count rates in the photopeak. calculated for the geometry of the room under study and the location of the detector. Application of the developed method makes it possible to estimate the average activity of natural radionuclides in building materials without destruction.

The Geometry of Steam Generator Tube and Its Relevance to the Occurrence of Stress Corrosion Cracking in Operating Nuclear Power Plants

2010 ◽  
Author(s):  
Deok Hyun Lee ◽  
Do Haeng Hur ◽  
Myung Sik Choi ◽  
Kyung Mo Kim ◽  
Jung Ho Han ◽  
...  
Keyword(s):  
Stress Corrosion ◽  
Steam Generator ◽  
Stress Corrosion Cracking ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Corrosion Cracking ◽  
Location Type ◽  
Steam Generator Tubes ◽  
Non Destructive

Occurrences of a stress corrosion cracking in the steam generator tubes of operating nuclear power plants are closely related to the residual stress existing in the local region of a geometric change, that is, expansion transition, u-bend, ding, dent, bulge, etc. Therefore, information on the location, type and quantitative size of a geometric anomaly existing in a tube is a prerequisite to the activity of a non destructive inspection for an alert detection of an earlier crack and the prediction of a further crack evolution [1].

Lifetime Management of EDF PWR Pressure Vessels and Pipings

2004 ◽  
Author(s):  
F. Hedin ◽  
J. C. Legendre
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Cost Benefit Analysis ◽  
Cost Benefit ◽  
Pressure Vessels ◽  
Destructive Testing ◽  
Key Points ◽  
Cast Stainless Steel ◽  
Non Destructive

Lifetime management of EDF PWR vessels and pipings are one of the main technical key points of safety and competitivness. This paper describes the EDF global approach in this field, which is applied to the nuclear fleet i.e 58 nuclear power plants, and particularly to the first 34 three loops, as far as lifetime is concerned: • operating procedures and routine maintenance, special maintenance and ten years safety reassessment, • engineering analysis, based on feed back experience, scientific knowledge, degradations mechanisms, causes and consequences management, • operating loadings decrease, • complementary deterministic and cost-benefit analysis, • fit for service justifications, • anticipation strategy to prepare future, based on Non Destructive Testing investigations, ability to repair and/or to replace components, in situ expertises, ... Some examples are given: lifetime management of reactor vessels heads and bottom penetrations of pressure vessels, fit for service of cast stainless steel primary pipings, primary nozzles and auxiliary pipings special maintenance.

Analysis of the Degradation Tendency of NPP Cables Using a Wireless Cable Indenting Robot

2013 ◽  
Vol 284-287 ◽  
pp. 1749-1753
Author(s):  
Kyung Nam Jang ◽  
Jong Soeg Kim ◽  
Sun Chul Jeong ◽  
Kyung Heum Park ◽  
Sung Yull Hong
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Condition Monitoring ◽  
Nuclear Power ◽  
Power Plants ◽  
Accelerated Aging ◽  
Test Equipment ◽  
Testing Time ◽  
Operation Period ◽  
Non Destructive

In nuclear power plants, there are many cables that perform safety-related functions. These cables should implement condition monitoring during the operation period in the nuclear power plant, in order to assess the remaining qualified life and extend the qualified life. In this study we focused on the indenting method which can measure the hardness of the cable jacket. This method is selected because it is non-destructive and requires short testing time and small sized equipment. In order to address the problems with the existing indenting test equipment, we developed new indenting test equipment, which could automatically move on the surface of the object cable. The newly developed equipment is designed for a small-sized and light-weight robot using wireless communication in order to implement condition monitoring in a harsh environment or locations that are inaccessible to the tester. The developed wireless cable indenting robot is composed of three parts, which are mechanical and electrical hardware parts and remote-control part. In order to analyze the degradation tendency of the cable, we prepared four thermally aged specimens and one un-aged specimen. Using the developed robot, we measured the modulus of the cable jacket of each specimen. The test data showed that the modulus of the cable jacket increased linearly as the accelerated aging time increased. From these results, we can analyze the degradation trends pertaining to cables installed in nuclear power plant according to the operation period.

Non-destructive testing of equipment and pipelines in nuclear power plants with RBMK

Atomic Energy ◽  
2012 ◽  
Vol 113 (1) ◽  
pp. 57-63
Author(s):  
Yu. G. Dragunov ◽  
B. P. Strelkov ◽  
A. A. Arefyev ◽  
A. S. Mokrousov ◽  
N. G. Roshchin
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Equipment And Pipelines ◽  
Non Destructive

scholarly journals Nuclear Power Plant Instrumentation and Control Cable Prognostics Using Indenter Modulus Measurements

2020 ◽  
Vol 6 (3) ◽  
Author(s):  
Dan McCarter ◽  
Brent Shumaker ◽  
Bryan McConkey ◽  
Hash Hashemian
Keyword(s):  
Condition Monitoring ◽  
Nuclear Power ◽  
Power Plants ◽  
Accelerated Aging ◽  
Remaining Useful Life ◽  
Test Bed ◽  
Efficient Operation ◽  
To Come ◽  
And Control ◽  
Non Destructive

As the fleet of nuclear power plants (NPPs) approach their1 original qualified life (typically 40 years) and operators seek license extensions, regulators require assurance that they can continue to operate safely in the decades to come. Some of the most important, yet often overlooked components, are the cables that provide the signal paths for instrumentation and control (I&C) systems used to ensure safe and efficient operation of NPPs.In response to this, the authors explore the use of expanding indenter modulus (IM), an industry-accepted technique for cable condition monitoring, into a prognostic tool for predicting the remaining useful life (RUL) of I&C cables. Not only is this technique non-destructive, but it can be performed while NPP cables are in service, thus making it practical for adoption into existing cable condition monitoring programs. In this paper, the authors describe an accelerated aging cable test bed used to acquire several types of measurement parameters as cables age. Additionally, practical techniques are described in which simple IM measurements can be leveraged for condition monitoring and RUL estimation.Error analysis indicates the proposed method is superior to conventional RUL estimation techniques, such as simple trending and curve fitting. The authors demonstrate that using IM can potentially provide a non-destructive, in-situ estimation of RUL for I&C cables. As described in this paper, the IM data clearly shows trends as a function of cable age, and shows promising performance for RUL estimation especially compared with conventional techniques.

NOMAD: Non-Destructive Evaluation (NDE) System for the Inspection of Operation-Induced Material Degradation in Nuclear Power Plants — Overview of the Neutron Irradiation Campaigns

2020 ◽  
Author(s):  
Inge Uytdenhouwen ◽  
Rachid Chaouadi
Keyword(s):  
Neutron Irradiation ◽  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Pressure Vessels ◽  
Material Heterogeneity ◽  
Non Destructive Evaluation ◽  
Surveillance Programs ◽  
Non Destructive

Abstract Worldwide there are more than 449 nuclear power plants (NPPs) in operation among which 329 reactors are older than 25 years and 94 will be operating for more than 40 years in 2020. Lifetime extensions are requested up to 50–60 years and sometimes even up to 80 years of operation for many existing NPPs. Long-term operation (LTO) of existing NPPs has therefore been accepted in many countries as a strategic objective to ensure supply of electricity for the coming decades. Within this strategy, the European Commission launched the NOMAD project, among others, through the Horizon-2020 programme. The reactor pressure vessels (RPVs) cannot be tested destructively in a direct way, neither can it be replaced. An indirect way is the use of Charpy samples from the so-called surveillance programs. The general strategy on the long term should focus on the ability to perform direct non-destructive evaluation (NDE) of the embrittlement of the vessel. NDE can be used to confirm that the data obtained by surveillance programs are being representative of the real state of the vessel for LTO. Moreover, a generic concern of large nuclear components such as the reactor vessel is the possible material heterogeneity such as macro-segregated regions which could eventually be located in the component but not in the baseline material used as surveillance material. Local non-destructive material inspection and comparison to reference materials in similar irradiation conditions would lead to a better assessment of the properties of the materials at any location of the vessel. The objective of NOMAD is to develop a tool that is capable of non-destructively evaluate the embrittlement of the vessel wall. The final system should be capable of inspecting the microstructure of the materials through the cladding. The tool that will be developed, will use existing and proven nondestructive testing techniques (NDT) with optimized and adjusted sensors. A combination of several techniques based on micro-magnetic, electrical and ultrasonic methods are investigated. Within NOMAD, they are calibrated and validated on a set of existing and newly irradiated samples consisting out of the most common RPV steels from Eastern and Western design, such as 22NiMoCr37, 18MND5, A533-B, A508 Cl.2, A508 Cl.3 and 15kH2NMFA. For the first time, a systematic study on a well-characterized set of samples that correlates the microstructure, mechanical properties, neutron irradiation conditions and non-destructive properties will be carried out. It will not only extend the existing database, but will include issues such as reliability, and uncertainty of the techniques as well as on material heterogeneity. The focus is laid on unbroken Charpy samples and large blocks with and without cladding to “simulate” the actual RPV inspection scenario. This paper gives an overview of the present status of the NOMAD project with focus on the outcome in WP1. The first preliminary NDE results from 6 set-ups and 28 parameters were compared with DBTT results from Charpy impact tests. They are very promising. Final results and detailed analysis will however only be available at the end of the project.

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