·Table of Contents
·Reliability and Validation 2
Quality Assurance for Non-Destructive TestingLiu Jinhong , Du Jianying , Zhou Zaiqi
( Suzhou Nuclear Power Research Institute, State Power Corporation, P.R.China)
Keywords: Quality Assurance, Non-destructive Testing
The quality system is maintained so that all the customer demands and regulatory requirements are satisfied during all our site applications of non-destructive testing activities.
3.1 Personnel qualifications
Inspector qualification is essential to a reliable inspection, and it is also mandatory required by regulatory bodies. China has such a NDT personnel qualification system that each industrial sector has its specific requirements in addition to the basic NDT society requirements. Therefore, in order to fulfill different requirements for different industrial applications, our NDT personnel hold different qualification certificates, including foreign certificates, to satisfy different customers for different requirements. Although much expenses are spent for the training and qualifications, our NDT personnel are well qualified in such a way.
3.2 Test equipment and material
Test equipment and material are very important for NDT inspections. As an inspection service organization, we developed and purchased all necessary equipment and materials for our services, including ultrasonic testing, radiographic testing, eddy current testing, magnetic particle testing, liquid penetrate testing, and visual testing as well as acoustic emission testing. These equipment and materials are mainly used in power generating industry and chemical industry for pressure vessel and related component inspections.
Periodic calibration of test equipments are carried out and documented so that their accuracy and tolerance are identified and controlled.
Test materials are controlled so that they are valid for the tests, and have no harmful to the component tested, which is extremely important to stainless steel component testing. For example, when stainless steel components for nuclear power plants are tested by ultrasonic testing method, the coupling material should contain very little amount of chlorinate, sulphate, phosphate materials, and should be qualified.
3.3 Test procedure
Test procedures define the responsibilities, techniques, operational steps and control means for specific method of testing and test objects. SNPI establishes a series of test procedures for different tasks, which we consider is necessary for carrying out quality services of testings.
3.4 Environmental conditions
Environmental conditions affect the test results seriously on some occasions. Attention should be taken for the temperature, humidity, radioactive, and/or surrounding materials to the test objects. For example, the ultrasonic transmission speed in the steel changes about 8 m/s when the temperature varies 1°; radioactive background of test objects affect the radiographic testing results.
3.5 Monitoring of NDT processes
As an important quality assurance measure, quality surveillance inspectors are assigned to verify the effectiveness of actual performance of NDT activities. The surveillance inspectors have very good background knowledge of NDT, they check the prerequisite of testing for a specific task, including NDT examiner's personnel qualification, status of test equipment and materials to be used, test procedures adapted, and the environmental conditions presented. They make sample checks to major test performance to verify if the test procedures are followed by the NDT examiners. They check also the test results to verify if the results are correct and the regulatory requirements are met.
Of course, the responsibility of testing is still on NDT examiner shoulders; the quality surveillance inspector is responsible for the verifications. Such verifications are normally carried out by means of implementation of witness and hold points inspections of quality plans for NDT testing.
The customers such as Guangdong and LingAo nuclear power joint venture companies, Suzhou chemical works, Jiangsu Changshu and Guangxi Liuzhou power plants give us high praise of the quality provided and reached as well as the quality management system implemented.
All feedback information are analyzed and used for continuous improvement of our quality of NDT services and our quality management system.
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