Study of in-service ultrasonic inspection practice for BWR piping welds

Technical Report · Mon Aug 01 04:00:00 EDT 1977

DOI:https://doi.org/10.2172/7089010· OSTI ID:7089010

Reinhart, E. R.

The occasional occurrence of intergranular stress corrosion cracks (IGSCCs) in bypass lines and core spray lines on boiling water reactors (BWRs) has made it desirable to quantify the response of Code-required ultrasonic inspection methods to flaws of this nature. To quantify the ability of the ultrasonic method to detect flaws, an evaluation of actual piping removed from operating plants, including both cracked and uncracked pipe samples, was performed. In addition to evaluation of the flaw detection and analysis capability of each inspection group, the variables of code interpretation, procedures, techniques, standards, equipment, and training were studied. The overall results of the program indicate that ultrasonic examination is a viable in-service volumetric inspection method for the detection of IGSCCs. The majority of the ultrasonic inspections found indications in essentially all of the flawed pipes (as determined by destructive examinations of specimens), but interpretation varied as to whether further confirmation was needed to establish the importance of the indications. Comparing the geometric location of the source of suspect signals with the previously established probable location of IGSCCs appears to be one of the most useful methods of analyzing data. Training of personnel specifically for the detection and analysis of IGSCCs appears to be the single most important factor in obtaining a high probability of correct inspection results. Techniques, equipment, and standards all influence the inspection process, but to a lesser degree. The program results have been used by EPRI to initiate programs intended to further improve the decision-making process of the inspector. The program results also indicate that the necessary guidelines have now been established for conducting future inspection quantification programs in the utility industry. The details of planning and conducting the study and analysis of the inspection results are covered.

• Research Organization: Electric Power Research Inst., Palo Alto, Calif. (USA)
• OSTI ID: 7089010
• Report Number(s): EPRI-NP-436-SR
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
210100* -- Power Reactors
Nonbreeding
Light-Water Moderated
Boiling Water Cooled
ACOUSTIC TESTING
BWR TYPE REACTORS
CHEMICAL REACTIONS
CORROSION
CRACKS
DEFECTS
IN-SERVICE INSPECTION
INSPECTION
JOINTS
MATERIALS TESTING
NONDESTRUCTIVE TESTING
PIPES
REACTORS
STRESS CORROSION
TESTING
ULTRASONIC TESTING
WATER COOLED REACTORS
WATER MODERATED REACTORS
WELDED JOINTS