Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Georgenthum, V.*; 杉山 智之; 宇田川 豊; 更田 豊志; Desquines, J.*
Proceedings of Water Reactor Fuel Performance Meeting 2008 (WRFPM 2008) (CD-ROM), 8 Pages, 2008/10
An analysis based on an Elastic Plastic Fracture Mechanics approach has been derived to understand the cladding failure conditions during the Pellet Cladding Mechanical Interaction phase of an RIA transient. The impact of incipient cracks at the cladding periphery has been evaluated through the calculation of J-integral. The J-integral is evaluated in a module coupled with the SCANAIR code and compared to the critical value of the J-integral deduced from the fracture toughness of Zircaloy. The clad metallography on CABRI and NSRR tested fuel rods provided the depth of brittle zone, i.e., the length of incipient crack. This analysis shows the J-integral can be used both in the elastic and elasto-plastic ranges to predict the failure occurrences. The study also points out that due to the strong dependence of hydride solubility with temperature, the conditions are more severe in the NSRR room temperature than in the CABRI or the Pressurized Water Reactor temperature.
Petit, M.*; Georgenthum, V.*; 杉山 智之; Quecedo, M.*; Desquines, J.*
Proceedings of EUROSAFE Forum 2007 (Internet), 9 Pages, 2007/11
Zirlo is an improved fuel cladding material that was developed to accommodate constraints associated with increasing burnups in a more severe duty operation. The behavior of Zirlo irradiated above 75 GWd/t under RIA conditions was studied in CABRI CIP0-1 and NSRR VA-2 tests. The samples were initially similar but VA-2 failed at relatively low enthalpy whereas CIP0-1 did not fail. Because test conditions were different in terms of initial temperature, coolant nature and power pulse width, it is necessary to use a transient fuel code to compare the two results. Using SCANAIR and CLARIS it was shown that the concentration of hydrogen precipitates at the temperature of the test is of primary importance to assess both experiments in a consistent manner. The analysis demonstrated that room temperature is a testing condition much more severe than that expected at typical PWR conditions.