Post-installed adhesive anchor bolts are commonly used on all types projects, from standard buildings to bridges and nuclear power plants. They are exposed to varying and diverse environmental conditions which are significant successfully to make connections to concrete structures for many years. In order to maintain the safety and reliability of concrete structures such as buildings or bridges on higher level over a long period time, we developed a new non-destructive inspection system of adhesive an...
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Development of non-destructive inspection technique for adhesive anchor bolts using AE sensor (1) An experimental approach

We have developed a non-destructive inspection technique using the AE (acoustic em sion) sensor. It is intended to be non-destructive evaluation in soundness of the adhesion anchor is installed in a nuclear power plant. We analyzed the Eigen frequ cy of the adhesive anchor measured by the AE sensor using a finite element method . Results of the analysis of the Eigen frequency, the change in Eigen frequency cou ld be confirmed between the adhesive anchor which simulates the Peeling of the resi n by aging de...
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Development of non-destructive inspection technique for adhesive anchor bolts using AE sensor (2) Theoretical examination

Test method has not been maintained for late-expansive aggregates (which cause cracks in concrete after 10 years or more), in addition to the early-expansive aggregates which have been considered as the major cause of ASR in Japan. In order to confirm the effectiveness of the aggregate test method of JNES flow (the method mainly composed of international methods RILEM AAR - 3 and AAR - 4) and to prepare applicable aggregate test method, we conducted comparative tests using domestic and foreign aggregate...
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Evaluation on Aggregate Testing Method for ASR Potential Evaluation

Time-of-flight ultrasonic measurements were conducted on a thick hexagonal block of 304 type austenitic stainless steel, which was used as a reflector in EBR-II and was irradiated to 23 ~ 33 dpa at 37 0 ~ 410 ?C. The results of ultrasonic-implied void swelling and carbide-induced densification were compared with those obtained by immersion density measurements and transmission electron microscope o bservations. The three types of measurements were found to agree rather well with each other, and the variati...
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Development of a non-destructive inspection technique for detecting irradiation-induced microstructural changes of austenitic stainless steels by use of an EBR-II reflector

Ultrasonic testing was conducted on two long (218-245 mm), Type 304 stainless steel blocks with a hexagonal cross-section (50 mm face-to-face thickness) that were removed from the reflector region of the decommissioned EBR-II reactor. Ultrasonic testing is one of the widely used non-destructive testing techniques for material characterization. Ultrasonic waves, currently used as a non-destructive technique to detect cracks, change as a result of interacting with microstructural components and can be em...
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Development of non-destructive inspection technique for microstructures under irradiation using austenitic stainless steel blocks

Development of methods of detecting degradation of irradiated reactor structural materials is required for successful operation of nuclear power plants. Ultrasonic waves, currently used as a non-destructive technique to detect cracks, change as a result of interacting with microstructural components and can be employed to measure radiation-induced changes in microstructure. Bulk-averaged measurements of microstructural changes can be determined usi ng ultrasonic velocity, attenuation and back-wall echo, wh...
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Development of non-destructive inspection technique for microstructuresunder irradiation using decommissioned materials(1) An experimental approach

Abstract It is desired to develop an ultrasonic inspection technique non-destructively measuring various forms of irradiation-induced degradation in structural components of nuclear reactors. In order to evaluate the depth distributions of ir radiation-induced microstructural changes, we have developed a numerical simulation model of ultrasonic wave changes caused by microstructural changes in austenitic stainless steel based on the developed theory of ultrasonic wave propagation for comparison with experi...
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Development of non-destructive inspection technique for microstructures under irradiation using decommissioned materials(2) An theoretical approach

An elemental factor on the crack propagation mechanism of SCC observed in LWRs component materials made of non-sensitization stainless steels is examined with respect to the local steam corrosion in cracks by atomic oxygen formed at the wall surface under the irradiation of γray. The excellent oxidation resistance of type 25Cr-35Ni EHP steel with forming the protective double layer oxides is observed up to 600℃. On the other hand, the oxidation of type 316L steel with non-protective single oxide is acc...
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Environmental compatibility evaluation of extra high purity stainless steel (EHP alloy)

We have developed Check Valve Inspection System using acoustic emission sensor and ultrasonic sensor, to examine degradation and detailed motion (Full open, Tapping, Oscillation, etc.) of the swing check valve. This inspection system was applied check valves in the seawater system line of domestic nuclear power plants. The examination was carried out before and after replacing the check valve. Comparing the results of the inspection system and the results of overhaul, effectiveness of this system has b...
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Development of check valve inspection technique