Model updates and performance evaluations on fuel performance code FEMAXI-8 for light water reactor fuel analysis

Udagawa, Yutaka; Amaya, Masaki

Journal of Nuclear Science and Technology, 56(6), p.461 - 470, 2019/06

https://doi.org/10.1080/00223131.2019.1595766

no abstracts in English

Development of fuel performance code FEMAXI-8; Model improvements for light water reactor fuel analysis and systematic validation

Udagawa, Yutaka; Yamauchi, Akihiro*; Kitano, Koji*; Amaya, Masaki

JAEA-Data/Code 2018-016, 79 Pages, 2019/01

JAEA-Data-Code-2018-016.pdf:2.75MB

FEMAXI-8 is the latest version of the fuel performance code FEMAXI developed by JAEA. A systematic validation work has been achieved against 144 irradiation test cases, after many efforts have been made, in development of new models, improvements in existing models and the code structure, bug-fixes, construction of irradiation-tests database and other infrastructures.

Study of the quality of vipac oxide fuel obtained by pyro-processing

Kakehi, Isao;

JNC TN9400 2000-054, 84 Pages, 2000/04

JNC-TN9400-2000-054.pdf:7.15MB

This report describes accomplishment of the study on the quality of vipac (vibro-packed) oxide fuel obtained by pyrochemical processing (molten salt electrolytic processing). This study is intended to contribute to the design study of the pyro-reprocessing-vipac fuel recycling system of oxide fuel. In this study, vibro-packing experiment has been conducted using granular U0 obtained by molten salt electrolytic processing (cold experiment). The oxide pyro process developed by Research lnstitute of Atomic Reactors (RIAR) is the method in which the sintered oxide is electrically deposited on the cathode at approximately 600C. 0xide granules for vipac fuel are obtained by crushing the oxide deposited on the cathode. This process is also developed as recycle process because it is capable of FP separation. Also in Japan, this process is studied as one of the new FBR fuel recycling systems. ln this study, we made an effort to clarify the mechanisms of vibro-packing of the electrically obtained granules, which influence on the effective parameters of vibro-packing density and fuel particles size distribution in the fuel cladding in case of non-sphere particles of the granules. As a result of the study, smear density of 75% and almost uniform distribution of U0 particles have been taken in the experiment, and much knowledge for the improvement of the vibro-packing quality has been found. And the possibility of the smear density over 80% and the uniform distribution of U0 particles has been suggested in this study.

Discovery of the shape controllable cavity surrounded by facets in ceramics

Serizawa, Hiroyuki

no journal, , 

My investigation on cavities in ceramics was triggered by the unexpected discovery of a polyhedral cavity in a UO matrix. The SEM image that attracted my attention was a cavity observed in the fracture surface of a single crystal of UO that was heat-treated in helium at 90 MPa, followed by annealing at 1573 K for 1 h. It was clear that the cavity was a negative crystal that was formed by the precipitation of helium during heat treatment after Hot Isostatic Pressing (HIP) injection. In a series of experiments, I noticed that the shape of the negative crystal changes depending on the heat-treatment history. A truncated octahedron-type, an octa-triacontahedron-type, and a pentacontahedron-type negative crystal were observed. Our study implies that the shape of the negative crystal should change depending on the helium inner pressure enclosed in the negative crystal.

Study on the minor actinide transmutation utilizing Monju data, 11; Heterogeneous core in which UO-matrix MA target fuel assemblies are loaded dispersively

Fujimura, Koji*; Oki, Shigeo; Takeda, Toshikazu*

no journal, , 

no abstracts in English

Study on the physical properties of non-stoichiometric oxide fuels with high minor actinide contents, 6; Evaluation of fuel properties for simulated MA containing oxide fuel

Muta, Hiroaki*; Kato, Naoki*; Tanaka, Kosuke; Matsuda, Tetsushi*; Oishi, Yuji*; Kurosaki, Ken*; Yamanaka, Shinsuke*

no journal, , 

Effect of MA and FP addition on thermo-mechanical properties of UO were investigated.

The Effect of carbonate ion on the dissolution rate of UO pellet

Moroi, Yuriko*; Kirishima, Akira*; Akiyama, Daisuke*; Sato, Nobuaki*; Kitamura, Akira; Kimuro, Shingo

no journal, , 

Development of spent nuclear fuel direct disposal system is one of important options in Japan to maintain flexibility of the back-end strategy of nuclear fuel cycle. Other countries like Sweden and Finland advance in research and development of the direct disposal system. However, it is known that some groundwater in Japan contains higher concentration of carbonate ion than that in Sweden or Finland. Therefore, the effect of carbonate ion on the dissolution rate of UO has to be discussed to evaluate feasibility of the direct disposal system in Japan.

Enthalpy measurement and evaluation of heat capacity on PuO

Morimoto, Kyoichi; Ogasawara, Masahiro*

no journal, , 

The heat capacity of MOX fuel is one of the important thermophysical properties. To evaluate the heat capacity of MOX fuel, the heat capacity of PuO is required because the heat capacity of MOX fuel is generally calculated from the compositional average of those of UO and PuO. The experimental results of the heat capacity of PuO are very scarce. In this study, the enthalpy of PuO pellet was measured in the temperature range from 980 to 2160 K with a drop calorimeter. In the measurement, the pellet was loaded in a tungsten container and a rhenium inner container was applied to prevent the reaction between the specimen and the tungsten container. It was found that the enthalpy increased at a constant rate with increasing temperature up to about 1900 K, and that above about 1900 K, its rate tended to increase with increasing temperature. It means that the heat capacity is raised when temperature exceeds about 1900 K.