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Yamaji, Akifumi; Suzuki, Motoe; Okubo, Tsutomu
no journal, ,
FEMAXI-6 is considered to be a powerful tool for developing an advanced LWR concept that utilizes MOX fuel rods, such as FLWR. In order to use this code, verifications with LWR MOX fuel irradiation data is necessary. In this study, the MOX fuel test data obtained from Halden reactor is used to verify FEMAXI-6. Up to about 40 GWd/t, the pellet temperature calculations through the gap conduction calculations are important to predict the fuel rod behavior. Especially, the FGR, pellet relocation, densification, and swelling are influential. These models in FEMAXI-6 have been developed based on UO
irradiation experience. However, the results show that these models can also be applied to LWR MOX fuel analysis except the FGR model.
Nakamura, Takehiko; Hanawa, Satoshi; Chimi, Yasuhiro; Sasajima, Hideo; Ogiyanagi, Jin; Nakamura, Jinichi
no journal, ,
Irradiation tests of new BWR fuels under abnormal transient conditions and water chemistry tests are planned in the JMTR. Facilities for the transient fuel irradiation tests and a water chemistry test loop are being constructed in the JMTR. In parallel, transportation of the test fuel and development of the sensors are progressing for the programs. Outlines of the programs are presented.
Sugiyama, Tomoyuki
no journal, ,
Udagawa, Yutaka
no journal, ,
Nagase, Fumihisa
no journal, ,
Integral thermal shock tests, simulating the LOCA sequences, and ring compression tests of the oxidized cladding were conducted in order to obtain information for safety evaluation of the high burnup fuel in a LOCA. Effects of high burnup are inconsiderable in terms of oxidation, ballooning and rupture behavior in the examined burnup range. Fracture boundary determined by the integral thermal shock test is not reduced significantly by high burnup and use of new alloys. The embrittlement criterion derived from the ring-compression test is quite different from the fracture boundary derived from the integral thermal shock test, due to the difference in the loading conditions. Most important sequence in terms of the safety for a LOCA and loading conditions in the sequence should be discussed and confirmed for selecting appropriate test methodologies and safety judgment with higher rationality.
Fukuda, Takuji
no journal, ,
no abstracts in English
Suzuki, Motoe
no journal, ,
Numerical analyses were performed by using the RANNS code for the NSRR experiments VA-1, VA-2 (room temperature tests), VA-3 and VA-4 (high temperature tests) using high burnup PWR fuels. The fuel changes during base-irradiation were calculated a by the fuel performance code FEMAXI-6 and the results were fed to RANNS as initial conditions prior to the pulse irradiation tests. The RANNS analyses were conducted for the temperature, stress/strain and PCMI of pellet and cladding, and the fuel conditions at failure instant or internal pressure change in the non-failed VA-4 test were evaluated. These results were compared with the actual cladding rupture morphology and factors dominating cladding failure were discussed. Also, a simulation calculation was carried out with a widened pulse power which has the same integrated enthalpy as that of the original NSRR pulse power in the VA-3 test. This suggests no possibility of cladding failure.