Nondestructive test/inspection

R. C. McMaster, ed., "Liquid Penetrant Inspection," Nondestructive Testing Handbook, Vol. 2, 2nd ed., American Society for Nondestmctive Testing, Columbus, Ohio, and the American Society for Metals, Cleveland, Ohio, 1982. 

It has developed a real time method to compare successive non-destructive inspections of the steam generator tubes in nuclear power plants. Each tube provides a safety barrier between the primary and secondary coolant circuits. Each steam generator contains several thousands of tubes whose structural integrity must be ensured through the lifetime of the plant, Therefore, Laborelec performs extensive nondestructive tests after each plant outage. 

Laser-based profilometry systems have also been applied for nondestructive testing and measurement of both smooth-bore and rifled gun tubes. Working through Small Business Innovation Research program, the U.S. Army has developed laser-based profilometry systems for the inspection of the 120mm cannon used on the MI-Al Abrams main battle tank. Systems have also been built to measure the erosion of 25 mm and 155 mm rifled gun tubes. 

Nondestructive Testing. Nondestmctive inspection of an explosion-welded composite is almost totally restricted to ultrasonic and visual inspection. Radiographic inspection is appHcable only to special types of composites consisting of two metals having a significant mismatch in density and a large wave pattern in the bond interface (see Nondestructive evaluation). 

Corrosion-fatigue cracks can be detected by nondestructive testing techniques such as magnetic particle inspection, radiography, ultrasonics, and dye penetrant. Corrosion-fatigue cracks may occur in numerous tubes simultaneously. Nondestructive testing of tubes at locations similar to those in which cracks are observed can be useftil. 

Most defects can be detected using one or more appropriate nondestructive testing techniques. However, in the absence of routine nondestructive testing inspections, identification of defects in installed equipment is generally limited to those that can be observed visually. Defects such as high residual stresses, microstructural defects such as sensitized welds in stainless steel, and laminations will normally remain undetected. Defects that can be detected visually have the following features ... 

Failure of clad- Implement routine inspections ding, allowing sub-, Implement periodic nondestructive testing strate to be exposed, leading to corrosion and potential failure. CCPS G-7... 

Welding Defects Visual, radiographic and/or ultrasonic Indications. Any welded joints. Basic welding problem laminated steel can cause trouble. Electrode manipulation. Control of welding speeds, procedures, careful inspection and nondestructive testing to locate defects for cutting out or repair. 

These techniques include (1) vibration monitoring (2) thermography, (3) tribology, (4) process parameters, (5) visual inspection and (5) other nondestructive testing techniques. This chapter will provide a description of each of the techniques that should be included in a full capabilities predictive maintenance program for typical plants. 

Formal inspection programs present a good opportunity for the water treatment service company representative to undertake an informal internal inspection to observe the various boiler surfaces first hand, perhaps undertake some limited nondestructive testing (NDT) work, and record the results of the previous 12 months water treatment management program. 

In addition, a variety of cleaning, inspection, and planned maintenance work is also required, including boil outs, lay ups, protection of idle boilers and nondestructive testing. Some of these many ancillary tasks are discussed in the following sections. 

The integrity of welded structures depends on the integrity of the welds, and much attention is given to testing methods, such as destructive tests, nondestructive tests, and general weld inspection. An objective of many tests is to determine whether welds contain specific defects, such as porosity, slag inclusions, cracks, or lack of fusion (14,15). 

Nondestructive evaluation, also termed nondestructive testing or nondestructive inspection, is extensively used in weld testing (14). Nondestructive tests do no impair the serviceability of the material or component under stress. The most widely used tests for evaluation of welds are liquid penetrant, magnetic particle, ultrasonics, and radiography. Acoustic-emission tests are increasingly used. Nondestructive tests detect and characterize, in terms of size, shape, and location, the various types of weld discontinuities that can occur. 

Nondestructive Testing. Nondestructive testing (NDT) is far more economical than destructive test methods, and every assembly can be tested if desired. Several nondestructive test methods are used to check the appearance and quality of structures made with adhesives or sealants. The main methods are simple ones such as visual inspection, tap, proof, and more advanced physical monitoring such as ultrasonic or radiographic inspection. The most difficult defects to find are those related to improper curing and surface treatments. Therefore, great care and control must be exercised in surface preparation procedures and shop cleanliness. 

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. 

Operation Inspection, testing Nondestructive testing, condition monitoring, corrosion monitoring, malfunction detection, plant degradation audits Plant safety audits... 

Perform nondestructive testing, inspection and maintenance programs to avoid SCC precursors, such as a concentration of stresses by localized corrosion. In case of protective coatings, routine maintenance is essential since scratches could create favorable sites for initiation of SCC. 

The soundness of welds is checked by visual inspection and by nondestructive testing (radiography). 

Control of welding speeds, procedures, careful inspection and nondestructive testing to locate defects for cutting out or repair. 

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