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hydride habit planesUdagawa, Yutaka
no journal, ,
Fukuda, Takuji
no journal, ,
It is guessed that it becomes penetration damage by the crack generation from hydride rim area in the outer part in the damage of the high burn-up fuel cladding in the RIA. This study reports on the result of evaluating the experiment that uses the EDC examination method as a method of simulating such a damage form. It reports on the result of experimenting on two kinds of pre cracking sample. One is the machining, the other is rolling.
fuel behavior during power transientsOgiyanagi, Jin
no journal, ,
no abstracts in English
Nagase, Fumihisa
no journal, ,
JAEA has been conducting LOCA studies with unirradiated and irradiated fuel cladding tubes. As a result, various information has been obtained on cladding oxidation, ballooning and rupture behavior and condition of fracture on quench of high burnup fuel. JAEA is proceeding the second phase of the experimental program with high burnup fuel cladding irradiated European power reactors. It is expected that the experiments provide information for future regulation of high burnup fuels which use advanced cladding alloys. More investigations on secondary hydriding, restraint loading and development of test methodologies are required for better understanding of the high burnup fuel behavior under LOCA conditions.
Suzuki, Motoe
no journal, ,
no abstracts in English
Sasajima, Hideo
no journal, ,
RIA-simulating pulse-irradiation tests were performed with 38-61 GWd/t PWR and BWR fuels as the TK and FK series. By using fuels which had similar irradiation histories in each test series, systematic results were obtained on hydride-assisted PCMI failure and fission gas release as well as on the failure conditions. In the PWR fuel cladding, radial cracks were generated in the hydride rim at the early phase of pellet-cladding mechanical interaction. In the high burnup BWR fuel cladding, radially-oriented hydrides have the influence on crack initiation and propagation. Higher FGR and larger deformation were observed in the fuels which experienced DNB during the pulse irradiations. To understand on post-failure events, data on dynamic fission gas release during the transient is needed. The information obtained in the TK and FK test series is valuable for clarifying the failure mechanism of the high burnup fuel, evaluating the results of the ALPS program and planning the future tests.
Suzuki, Motoe
no journal, ,
no abstracts in English
Hanawa, Satoshi; Ogiyanagi, Jin; Chimi, Yasuhiro; Nakamura, Jinichi; Nakamura, Takehiko
no journal, ,
no abstracts in English
Chuto, Toshinori
no journal, ,
In order to investigate effect of burnup on high temperature oxidation of the advanced cladding alloy, isothermal oxidation test was performed with specimens prepared from high burnup fuel cladding which were irradiated up to 79 MWd/kg as well as non-irradiated cladding. Oxidation kinetics was evaluated from weight gain and oxide layer growth. Growth of the inner surface oxide layer formed in the irradiated cladding is almost equivalent to that in the non-irradiated cladding, while growth of the outer surface oxide layer is slightly smaller in the irradiated cladding. It is considered that the oxidation at the outer surface is suppressed by the pre-formed corrosion layer. Results of the weight gain measurement also suggest lower oxidation rates in the irradiated cladding. Consequently, it is concluded that high-burnup effect on high temperature oxidation is small for the examined range, though pre-formed corrosion layer may have the protective effect.
Amaya, Masaki
no journal, ,
A pulse irradiation experiment using the NSRR under high temperature- high pressure condition was carried out on a mixed-oxide (MOX) fuel rod which was irradiated in a light water reactor up to high burnup, and fission gas release from MOX fuel pellet during reactivity-initiated accident (RIA) was investigated. From the puncture test result of the test rod after the pulse irradiation, fission gas release from fuel pellet was estimated as about 40%. Based on the EPMA results on a cross section of the test rod after the pulse irradiation, the fission gas release from plutonium-rich region (Pu spot) was estimated as about 12%. From the comparison between the measured and estimated values, it is suggested that fission gas released also from the region excluding Pu spot. Large cladding residual hoop strain was observed in the fuel rod after the pulse irradiation. It is likely that an increase of rod inner pressure due to fission gas release acts as a driving force of the deformation.
fuel irradiated in the HBWRNakamura, Jinichi
no journal, ,
High burnup BWR UO and MOX fuel were re-irradiated at HBWR (Halden reactor) to measure the fuel center temperature and rod inner pressure in order to obtain the fuel behavior data such as fission gas release. The fission gas release data of UO fuel suggested that the fuel temperature threshold for fission gas release at high burnup is lower than Vitanza threshold based on low/middle burnup data. The fission gas release of MOX fuel was larger than that of UO fuel. This difference may be attributed to the formation of open porosity of MOX fuel due to the growth and coalescence of fission gas bubbles at higher power than UO fuel during base irradiation.
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