Inspection nondestructive examination

G. Passi und S. Passi MUTOS Equipment for increasing reliability of ultrasonic weld inspection. International Conference Advanced Technologies in Welding and nondestructive examination. Proc., Tel-Aviv, 1993, p 32-34... 

The surface condition of the finished weld shall be suitable for the proper interpretation of the inspection and nondestructive examinations. In those cases where there is a question regarding the evaluation/interpretation, the actual weld surface condition shall be compared for verification. 

This Chapter includes the requirements for inspections by owner, quality control examinations, nondestructive examinations, and specified tests by the construction organization (manufacturer, fabricator, or erector). Inspection, examination, and testing shall be in compliance with the general requirements of Chapters GR-4 and GR-6, as well as the applicable specific requirements in this Chapter and engineering design. 

Inspection is usually done by nondestructive techniques. This is usually known as nondestructive examination (NDE). The general term nondestructive evaluation describes the various terms used such as nondestructive inspection (NDI), nondestructive testing (NDT) and nondestructive examination (NDEx). Some of the aspects or purpose of these techniques involve detection and evaluation of flaws, leaks, dimensions, location (position), microstructures, mechanical properties and stress. 

The interim examination and maintenance cell is a shielded hot-cell complex that conducts nondestructive examinations of test assemblies and core components under controlled argon-atmosphere conditions. (Its location is shown in Fig. A.l). The hot cell can also be used to perform limited maintenance of plant equipment or to prepare plant equipment for transfer to other maintenance facilities. The cell contains equipment necessary for disassembly, reassembly, and requalification of test assemblies and components. Nondestructive examinations that can be performed include dimensional checks, weighing, gamma scanning, visual inspections, and photography. Sodium removal facilities are also included. 

Prior to, during, and after fabrication of the reactor vessel, nondestructive tests based upon Section III of the ASME Boiler and Pressure Vessel Code are performed on all welds and forgings as indicated. The nondestructive examination requirements including calibration methods, instrumentation, sensitivity, reproducibility of data, and acceptance standards are in accordance with requirements of the ASME B PV Code, Section III. (See Table 5.2-1). These methods, procedures and requirements are compatible with Section XI of the ASME Code so that results of preservice inspections can be correlated with in-service inspections. Strict quality control is maintained in critical areas such as calibration of test instruments. 

The bolting material for the reactor vessel closure head is fabricated from SA 540, B23 or B24, Class III material. This material conforms to the requirements of 10 CFR 50, Appendix G and the intent of Regulatory Guide 1.65, "Materials and Inspections for Reactor Vessel Closure Studs." Nondestructive examination will be performed according to Subarticle NB-2580 of Section III of the ASME Code, during the manufacturing process. 

Nondestructive examination A mettrod of examination or inspection of a material or object which does not destroy or otherwise degrade the subject. 

The expression nondestructive examination (NDE) is a generic term encompassing visual inspection and the following techniques ... 

The disadvantages and limitations of the plate layered vessels lie in reduced fatigue strength at critical welding and discontinuity locations as well as in the difficulty to inspect these locations with the available nondestructive examination methods. If a plate-wound vessel fails due to fatigue cracks or overloading, then the failure mode is relatively safe due to multiple shells and the superior mechanical properties of thin plates [17]. 

Nondestructive examination techniques (ultrasonic testing (UT) and eddy current testing (ET)) shall be used to demonistrate that the reactor tank and the PWS piping will maintain their integrity under the operating conditions. The restart criteria for the reactor tank, based on the UT inspection, will be in accordance with WSRC-RP-89-208, "Tank UT Acceptance Criteria" (Reference 1). 

Speckle shearing interferometry, or shearography, is a full field optical inspection teclmique that may be used for the nondestructive detection of surface and, sometimes, subsurface defects. Whilst being more sensitive in the detection of surface defects, it may also be considered for pipe inspection and the monitoring of internal conoslon. In contrast, laser ultrasound and other forms of ultrasound, are point by point measurement techniques, so that scanning facilities and significant data processing is required before information on local defects is extracted from any examination of extensive areas [1 - 3]. 

In reality, the identification of one or more forms of corrosion requires visual observation, nondestructive inspection methods, optical microscopic examination, and sometimes electron scanning microscopy, etc. The first study of the corrosion appearance of a case should divide corrosion into uniform and localized corrosion. Localized corrosion can be further identified as macroscopic or microscopic local corrosion. Microscopic attack refers to a minute amount of dissolved metal, accompanied by considerable damage, before the phenomenon becomes visible to the naked eye. 

Over the past two decades there have been several studies of human reliability in aircraft structural inspection (Rummel et al. 1989 Spencer and Schurman 1995 Muigatroyd et al. 1994). AU of these to date have examined the reliability of nondestructive inspection (NDI) techniques, such as eddy current and ultrasonic technologies. 

Visual inspection is obviously an optical matter that includes noninstrumental assessment of aspects of appearance such as gloss, color matching against standard colors, and detection of flaws. Optical microscopy is an extension of visual inspection that makes examination of small details of appearance and structure possible. Visual inspection is also a nondestructive technique and this aspect is considered further in Chapter 32. Microscopy is an art and science of its own, and in-depth treatment of it is beyond the scope of this book. 

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