Fracture behavior of non-irradiated Zircaloy-4 fuel cladding with a pinhole under simulated LOCA condition

LOCA時におけるピンホールを有する未照射ジルカロイ4被覆管の破損挙動

岡田 裕史

Okada, Yuji

In a case where a pinhole leak occurs in a fuel rod incidentally, it is possible that coolant enters the fuel rod through the pinhole. Since knowledge about the behavior of the fuel rod with a pinhole under LOCA conditions is limited, semi-integral quench tests were performed with non-irradiated zircaloy-4 fuel cladding tubes with a pinhole in order to investigate the difference in the fracture behaviors between normal and leaker fuels under LOCA conditions. Initially injected water affected the oxidation behavior of the inner surface of cladding during the test, and the fracture boundary of the test rod was dependent on not only the axial restrained condition during the test but also the existence of a pinhole and initially injected water. This tendency seemed to be related to the amount of oxidation of cladding inner surface caused by the steam which remained in or entered the test rod during the test.