Aging power plants are requiring more nondestructive evaluation (NDE) and more cost effective NDE. A nondestructive evaluation workstation (NEW) can provide the means of achieving cost-effective NDE. It consists of a multipurpose NDE computer for any or all of the following: (1) examination planning and development, (2) data acquisition, (3) data processing and analysis, (4) forms and report generation and (5) data exchange. For example, if a power plant wants to contract out a computer-assisted ultrasonic examination, they can require that the data be delivered in a standard Intermediate File Format (IFF). They can then review the data on their own NEW. Enterprising contractors also have the opportunity to compete on follow-up evaluations and examinations by offering a compatible NEW. The author discusses a PC-based ultrasonic NEW developed and used extensively at Pacific Gas and Electric (PG&E).

Fossil power plant operating and maintenance cost reduction efforts coupled with changing plant operating modes have rendered traditional approaches to plant component condition assessment inadequate. New NDE techniques are required to meet utility needs in this changing environment. Key attributes of such new techniques will be improved measurement speed and accuracy, reduced preparation requirements, automated data acquisition, and computer-based analysis support. In addition, tools will be required to assist power plant personnel in making the best decisions on what, when, and how to inspect plant components to achieve overall economic objectives.

Thermal embrittlement, which can occur during normal operating conditions, may reduce the fracture toughness of materials to the point that structural integrity becomes suspect. Much of the data reported in the literature is based on using impact energy to quantify the extent of embrittlement experienced by base metal specimens. These data provide a useful, qualitative description of the embrittlement but are of limited use in predicting structural integrity when there are cracks in the base metal or in weldments. This paper presents fracture toughness data for both base metal and weldments exposed at 649 degrees Celsius for times up to 5000 h. In addition, preliminary results are provided regarding the use of nondestructive examination (NDE) techniques to predict changes in fracture toughness.

The application of infrared thermography (IR) to electric utility applications is discussed. A joint program with electric power research institute (EPRI) demonstrated the inspection of specific power plant components including boiler casing, condenser air-inleakage, and condenser tube leakage. Infrared thermography was successfully demonstrated as a predictive maintenance tool for power plant applications and real dollar savings by the utility.

As the nation's power consumption continues to increase in conjunction with stricter environmental requirements, the need for monitoring the effectiveness of mist eliminator systems becomes a key issue. Techniques for monitoring the performance of these systems under operating conditions is vital for the industry in determining locations of high outages of flue gas desulfurization. This paper discusses one type of instrumentation for monitoring MES performance, the technique and the benefits provided to the industry.

This paper discusses a new technique for locating and detecting wall thickness reduction in boiler tubes caused by erosion/corrosion. Traditional means for this type of defect detection utilizes ultrasonics (UT) to perform a point by point measurement at given intervals of the tube length, which requires extensive and costly shutdown or `outage' time to complete the inspection, and has led to thin areas going undetected simply because they were located in between the sampling points. Pulsed infrared imaging (PII) can provide nearly 100% inspection of the tubes in a fraction of the time needed for UT. The IR system and heat source used in this study do not require any special access or fixed scaffolding, and can be remotely operated from a distance of up to 100 feet. This technique has been tried experimentally in a laboratory environment and verified in an actual field application. Since PII is a non-contact technique, considerable time and cost savings should be realized as well as the ability to predict failures rather than repairing them once they have occurred.

Over the past several years lasers have been employed in an ever widening number of applications in an incredibly diverse set of markets. In the area of nondestructive testing, however, laser-based systems have only recently made inroads into the commercial markets. About ten years ago QUEST Integrated, Inc., began working with the U.S. Navy to adapt the principal of laser triangulation to solve a serious maintenance related problem. The internal surfaces of marine boiler tubes were experiencing pitting and corrosion which had resulted in catastrophic shipboard failures. At that time, conventional visual methods only allowed operators to inspect the first eighteen inches of the tube using a rigid borescope. If any pits were located, a mechanical stylus mechanism was used to obtain an approximate depth measurement of the pit. The condition of the balance of the tube was then extrapolated based on this extremely limited amount of information. Often the worst pitting was found in the bends of the tube, which could not be inspected by the visual method. Finally, a catastrophic boiler failure on an aircraft carrier resulted in the initiation of a search by the U.S. Navy for a better solution. Quest was contracted to develop an articulated probe which could negotiate the full length of a boiler tube with multiple bends, and generate a complete digital map of the inside surface. A key requirement of this probe would be rapid and quantitative measurement of internal features such as ID pits and corrosion. In 1987 QUEST delivered the first laser- optic tube inspection system to the U.S. Navy for use in marine boiler tubes. The Laser Optic Tube Inspection System (LOTIS^TM) was immediately put to use and paid for itself many times over in reduced maintenance costs. Over the next six years several generations of LOTIS were developed for the U.S. Navy, each one providing more capabilities, improved inspection speeds, and more user friendly operator interface. Today, LOTIS is used for routine inspections on marine boiler tubes by the U.S. Navy, with units located in several parts of the United States and overseas. In 1993 QUEST began exploring the possibility of extending this technology to the inspection of commercial tubes used in power generation and chemical processing. The following is an overview of the use of laser profilometry for nondestructive testing.

Eddy current testing (ET) is routinely used to assess tubing condition in heat exchangers at power plants. Generally, ET results provided by typical final report formats are not well- suited for facilitating condition assessments, especially when the component has a significant number of tubes. The main condenser at Calvert Cliffs Nuclear Power Plant (CCNPP) Unit #1 contains nearly 50,000 tubes. An accurate condition assessment based on 2,500 pages of final reports generated from a 100% condenser inspection in 1992 proved difficult, if not impossible, without some type of automated data management system. With the aid of a data management system, engineering recommendations, founded on database queries and graphics, can be made quickly and reliably. These displays effectively communicate information about overall condition, are helpful in making operating decisions, and aid in predicting future performance. Standard procedures for critical heat exchanger inspections require trending of indication growth over time to determine a rate of tube degradation. Specifically, for the 1994 ET inspection of CCNPP Unit #1 condenser, the size of indications were compared against their 1992 value to determine a mean growth rate. The results of these efforts are presented along with a discussion of how Baltimore Gas and Electric has used eddy current data to prolong the operating life of this condenser while ensuring leak tightness.

The current inservice inspection activities at a U.S. nuclear facility are based upon the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code, Section XI. The Code selects examination locations based upon a sampling criteria which includes component geometry, stress, and usage among other criteria. This can result in a significant number of required examinations. As a result of regulatory action each nuclear facility has conducted probabilistic risk assessments (PRA) or individual plant examinations (IPE), producing plant specific risk-based information. Several initiatives have been introduced to apply this new plant risk information. Among these initiatives is risk-based inservice inspection. A code case has been introduced for piping inspections based upon this new risk- based technology. This effort brought forward to the ASME Section XI Code committee, has been initiated and championed by the ASME Research Task Force on Risk-Based Inspection Guidelines -- LWR Nuclear Power Plant Application. Preliminary assessments associated with the code case have revealed that potential advantages exist in a risk-based inservice inspection program with regard to a number of exams, risk, personnel exposure, and cost.

Nondestructive evaluations of aging infrastructure provide a powerful means of detecting structural degradation. However, once a defect is detected, there is the problem of dispositioning it, i.e. deciding on the significance of the defect relative to structural integrity. Fracture mechanics procedures can be used to analyze the future behavior of detected defects, thereby providing guidance in run/repair/retire decisions. The purpose of this paper is to provide an example of the use of probabilistic fracture mechanics to predict the failure rate of a 304 stainless steel weldment in a typical boiling water reactor piping system. The weldment is considered to have a crack of an indicated size that has been identified by a nondestructive inspection, and the predicted failure rate is used in dispositioning of the indicated defect. A target reliability is suggested, and run/repair/replace decisions are based on the predicted reliability relative to the target. The results of an example problem are presented to show the suggested procedure. The example problem showed an exceedance of the target failure probability at short time following the inspection.

Research literature documents several nondestructive (NDE) techniques for measuring material properties such as residual stress, embrittlement and fatigue damage. Reports in peer reviewed publications thoroughly describe the experimental measurement techniques and provide a comparison between expected analytical results and experimental measurements. A simple rationale for estimating the required accuracy of NDE to measure residual stress shows that residual stress measurements are acceptable if accurate to within plus or minus 10%. An analysis of the effect of neutron fluence on fracture toughness shows a more complex relationship. At temperature and fluence conditions corresponding to low toughness; fracture toughness is insensitive to fluence and high accuracy for NDE embrittlement is not required. However, for conditions associated with high toughness, changes in fluence have significant effect. Calculations indicate that NDE measurements of irradiation effects should have an accuracy of approximately plus or minus 15% to correspond to a plus or minus 10% change in K_IC over the toughness range from about 40 to 100 ksi(root)in.

Non-intrusive examination methods are currently being developed and initially implemented to evaluate the performance and operability of check valves in nuclear power plants. These methods are used in lieu of disassembling and inspecting the check valves to detect underlying causes or degradation that may lead to failure of this important equipment when it is called upon to perform a critical safety function. Risk-based methods are currently being developed to determine which check valves and their inherent failure modes are important to the safety of the plant from a core damage risk perspective. Risk-based methods are also emerging to evaluate the effectiveness of current and emerging inservice testing methods, such as non- intrusive examinations, particularly for the risk-significant check valves. Finally, decision analysis and value-impact methods are used to evaluate the safety and economic trade-offs in the development of an inservice test program for all check valves. This paper summarizes the latest work from this application currently being developed within the nuclear industry.

Acoustic emission (AE) monitoring techniques have been applied successfully to high voltage transformers, to aid in the detection and source location of the origin of partial discharge (PD) events. Three dimensional source location techniques have been applied in the manufacturing environment evaluating suspect transformers based on capacitance measurements. Good correlation levels have been established with the capacitance microvolt measurement and AE activity. Accurate source location has been confirmed by visual examination. Field substation transformers have also been evaluated using the same technique. Suspect transformers based on high combustible gas levels were monitored. Correlation has been established between high combustible gas levels and AE activity. Accurate source location has been confirmed by visual examination. Test procedures and acceptance criteria are being evaluated for new and in- service transformers. Both of the above case studies are presented in this paper.

This paper discuses Bonneville Power Administration's recent field experiences combining old and new technologies and techniques as a diagnostic tool for transformer maintenance. Several cases studied during the past 2 years are briefly discussed in the case history section.

Vetco Pipeline Services, Inc. (VPSI) has been using the magnetic flux leakage (MFL) technique to inspect operating pipelines and above ground storage tanks for many years. This technique involves magnetically saturating the material under inspection and scanning the surface of the material for MFL fields caused by wall thinning defects. Recently, VPSI has adapted this technology for the inspection of in-service distribution pipelines. This new inspection system couples the MFL techniques used for pipeline inspection to a novel delivery system for the specific task of gathering real time data on the condition and integrity of distribution pipelines. The focus of this paper is to review this application of the magnetic flux leakage technique to describe the novel delivery systems developed and to detail the enabling technologies that now allow real time capture and analysis of inspection data.

PLS International introduces its technology to visually examine the internal condition of in- service low pressure distribution piping. The PLS 3000* Enhanced Pipeline Inspection System has the capability to visually examine 3 inch to 8 inch cast iron, steel, and plastic in-service piping to distances to 1000 linear feet through a sealed removable access fitting. PLS proprietary pipe crawling robots are capable of examining 8 inch to 60 inch diameter piping to 2000 linear feet through sealed accesses from a single excavation. A summary of benefits to distribution companies by employing this technology is detailed. Actual color videotape and videophotographs are presented as documentation.

Under the sponsorship of the Gas Research Institute (GRI), of Chicago, Illinois; INVOCON, Inc. (IVC) and Maurer Engineering, Inc. (MEI) are developing a unique, cost-efficient pipe inspection method employing ultrasonic technology. This article examines the gas industry's need for improved methods of inspection and the role that this new method can play in the satisfaction of that need. Subsequently, the article describes the system being developed. The narrative is supported by drawings of the engineering prototype. The system focuses on inspection of the three most common materials used in natural gas distribution systems: cast iron, steel, and plastic.

Saudi Aramco has many thousands of kilometers of carbon steel cross-country pipelines, in- plant piping, and hundreds of process vessels that may experience environmental conditions favorable for the formation of several different types of cracking. Two types of cracking of particular interest to the company's engineering and production personnel are caustic stress corrosion cracking propagating from the inside to outside of process piping walls and hydrogen induced cracking (HIC) in piping and vessel walls. The occurrence of these cracks in operating piping and large vessels, when undetected, may present problems due to potential failures during operation of systems and facilities. Once the location of cracking is known, the extent and severity of the problem can usually be determined using suitable nondestructive examination (NDE) techniques. Screening methods offering accurate detection and location of cracking and capable of 100% inspection of a given piping system or vessel need to be developed. Examples of how the two types of cracking are normally located along with details of the nondestructive characterization methods used are presented.

Damage to municipal wastewater systems has received much attention over the past decade. Many new rehabilitation methods have been developed. Improved inspection methods have not kept pace. The standard and accepted tool is video inspection which is valuable, but has limitations. A complementary system for large line inspections is the caliper tool. Caliper tools are deployed like video tools, and provide direct measurements to show displacement, corrosion, debris, alignment, or other parameters in the inspected pipe. Several types of caliper tools are discussed and examples of field and laboratory programs are presented.

Many sewers in America's cities are more than 125 years old and are subject to structural failure. In one year alone, St. Louis, Missouri had 4,000 sewer collapses that carried an astronomical repair tag. When a sewer caves in, it often takes the street, sidewalks, and surrounding buildings along with it endangering public health and safety. The ideal situation would be to repair a sewer before such cave-ins occur, as emergency repairs are far more costly than preventive measures. The question addressed by this paper is how to detect unseen problem areas in sewer systems before collapses occur. At the present, progressive sewer administrations may use crawl crews or remote controlled video cameras to inspect sewers at suspected problem locations. This can be extremely costly, dangerous, and not very accurate, as a void around the outside of the sewer is often invisible from within. Thus, even a crawl crew can fail to detect most voids. Sewer districts and independent engineering firms have found infrared thermography, a nondestructive testing method, to be extremely accurate in finding sewer voids, and accompanying pipeline leaks, before they can cause expensive and dangerous problems. Infrared thermography is a non-contact, remote sensing method, with the potential for surveying large areas quickly and efficiently.

This paper reviews the details of a sewer system, identifying the important aspects since any rehabilitation must be in conformance with the use and characteristics of the system. The discussion then reviews the general methods used to establish the condition of a sewer system and the need for repair. The paper closes with a review of the various methods currently used for rehabilitation of sewer systems and indicates the advantages of the use of such trenchless technologies.

Trenchless Technology Consultants is a sewer rehabilitation company that offers solutions to problems using a variety of `no-dig' techniques. This paper reports on one particular problem that we were asked to solve, a new building complex which was occasionally being flooded as the sewers could not cope with the flow.

Computerized infrared thermographic pipeline inspection is now a refined and accurate process having been thoroughly proven to be accurate, cost effective, and efficient technology for pipeline rehabilitation programs, during a 10 year development and testing process. The process has been used to test pipelines in chemical plants, water supply systems, steam lines, natural gas pipelines and sewer systems. Its non-contact, non-destructive ability to inspect large areas, from above ground, with 100% coverage and to locate subsurface leaks as well as the additional capability to locate voids and erosion surrounding pipelines, make its testing capabilities unique and highly desirable. This paper details the development of computerized infrared thermographic pipeline testing along with nine case histories illustrating its implementation problems and successes during various rehabilitation programs involving pipelines carrying water, gas, petroleum, and sewage.

This paper is an `extended abstract' for a more complete presentation at the SPIE Conference on Nondestructive Evaluation of Aging Infrastructure, scheduled for June 6 - 8, 1995 Oakland, California. The physical and economic climate of electric power generation, particularly for aging fossil-fuel plants, is reviewed. This calls for reliable sensing and monitoring/control systems to extend equipment life and preclude major breakdowns. An instrumentation system requirement is outlined for a cold reheat header located in the high temperature and contaminated/corrosive environment of the fluc-gas stream of a 480 MW fossil-fuel boiler. The development and installation of what is believed to be the world's first distributed fiber optic temperature and strain/displacement monitoring system, operating at 1100 degrees F, is reviewed. The nature of initial data acquisition and planned future system operation for improved plant health are presented. The installation of a discrete fiber optic system for main steam lines is also presented. Drawing on the technology and experience with the aforementioned development and installation, the planned function of the system is to provide data on thermally induced stresses (creep) for strain reduction by operational control.

The Gas Research Institute (GRI) has been supporting a comprehensive research and development program on in-line inspection techniques for natural gas transmission pipelines. This program contains assessments of state-of-the-art nondestructive evaluation methods, improvements in current approaches, and developments of advanced inspection technologies. The elements of the GRI Nondestructive Evaluation Program range from laboratory evaluations of the capabilities of inspection technologies to large-scale measurements in simulated pipeline settings. Each level of research stresses a quantification of both the limits of detection and the accuracy of characterization of pipeline imperfections that are found by in- line inspection tools. The overall goal of GRI's Nondestructive Evaluation Program is to develop and improve technologies that will help gas pipeline companies maintain the physical integrity of their transmission systems, prevent pipeline shutdowns, and reduce maintenance costs. This paper summarizes the results of the GRI program to date in relationship to their direct application to in-line inspection of gas transmission pipelines. The program consists of three main elements: facilities development, research on current inspection technologies, and research on future inspection technologies. The facilities development is centered around the Pipeline Simulation Facility; the research on current inspection technologies is aimed at improving magnetic flux leakage analyses; and the research on future inspection technologies is centered on stress-corrosion crack detection and characterization.

The increasingly popular Remote Field Electromagnetic Technique(RFET) is being utilized for larger diameter piping. This is particularly useful for the inspection of Underground Gas Distribution Lines. The Proof-of-Principle of the method including the sensitivity and limits of detection for both pitting and wall thinning is presented in this paper.

I am pleased to welcome you to this timely and informative conference organized by The International Society for Optical Engineering (SPIE). As Conference Chair, I amvery pleased, but not at all surprised, by your interest and enthusiastic response: Over 300 participants are contributing over 210 technical papers to six topical conferences.

The infrastructure in the United States and the world is aging. There is an increasing awareness o the need to assess the severity of the damage occurring to our infrastructure. Limited resources preclude the replacement of all structures that need repairs or have exceeded their lifetimes. Methods to assess the amount and severity of damage are crucial to implementing a systematic, cost effective approach to repair and/or replace the damaged structures. The challenges of inspecting aging structures without impairing their usefulness rely on a variety of technologies and techniques for nondestructive evaluation. This paper will briefly describe several nondestructive evaluation technologies that re required for inspecting a variety of systems and structures.

the role of the National Laboratory in technology transfer is to help industry implement the latest technology. The National laboratory must have a unique capability that does not compete with tax paying companies. Typically a National Laboratory will demonstrate the benefit of applying NDE to a company's production line. The company then contracts with a vendor to supply a production inspection system based on the laboratory's demonstration. Both the company and the vendor benefit from the participation with the National Laboratory. The company improves the quality of its products and the vendor has a new product to market. The purpose of this paper is twofold: (1) to present a brief overview of NDE capabilities and application activities within the National Laboratory System and (2) to identify NDE point-of- contacts at each laboratory.