Improved-EDC tests on the Zircaloy-4 cladding tube with an outer surface pre-crack

Abstract

In order to investigate the failure behavior of fuel cladding under a reactivity-initiated accident (RIA) condition, biaxial stress tests on unirradiated Zircaloy-4 cladding tube with an outer surface pre-crack were carried out under room temperature conditions by using an improved Expansion-Due-to-Compression (improved-EDC) test method which was developed by Japan Atomic Energy Agency. The specimens with an outer surface pre-crack were prepared by using Rolling-After-Grooving (RAG) method. In each test, a constant longitudinal tensile load of 0, 5.0 or 10.0 kN was applied along the axial direction of specimen, respectively. All specimens failed during the tests, and the morphology at the failure opening of the specimens was similar to that observed in the result of post-irradiation examinations of high burnup fuel which failed during a pulse irradiation experiment. The longitudinal strain (ε tz ) at failure clearly increased with increasing longitudinal tensile loads and the circumferential strain (ε tϑ ) at failure significantly decreased in the case of 5.0 and 10.0 kN tests, compared with the case of 0 kN tests. From these tests, the data of cladding failure were obtained in the range of strain ratio (ε tz /ε tϑ ) between about −0.6 and 0.7: this range of strain ratio covers the range between about 0.0 and 0.7 which is estimated in the case of RIAsimulated test. It is considered that the data obtained in this study can be used as a fundamental basis for quantifying the failure criteria of fuel cladding under a biaxial stress state.

The effect of strain biaxiality on the fracture of zirconium alloy fuel cladding

“…Shinozaki et al [17][18] and Li et al [19] developed a type of EDC test in which the sample experiences tensile axial strain as well as tensile hoop strain. Therefore, the strain biaxiality is very similar to that experienced by fuel cladding during PCMI.…”

Development of Standardized Property Requirements, Measurement Methods, and Reporting Guidance for Coatings

“…Microcantilever testing isolates and tests the fracture strength of the coating, but also requires significant equipment and expertise [5]. From the standpoint of understanding and measuring the fundamental/idealized strength of a coating, this technique is the most direct.…”

“…However, different coating materials, thicknesses, coating processes, process parameters, and testing methods have an impact on the microstructure and mechanical properties and therefore on the results of the applied investigation methods, which makes the licensing of a selected coating cumbersome [4]. A large variety of methods has been developed to investigate coatings for cladding materials and their mechanical properties [5][6][7][8][9]. Coating performance must be evaluated with respect to the applied coating technique.…”

Microstructure Investigation and Mechanical Properties of Coated Zircaloy Cladding

“…Different coating materials, thicknesses, coating processes, process parameters, and testing methods have an impact on the microstructure and mechanical properties and therefore on the results of the applied investigation methods, which makes the licensing of a selected coating cumbersome [4]. A large variety of methods have been developed to investigate coatings for cladding materials and their mechanical properties [5][6][7][8][9]. Coated zirconium cladding concepts have grown to become prioritized approaches of industry ATF efforts.…”