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Miyoshi, Yoshinori; Yamamoto, Toshihiro; Nakajima, Ken
JAERI-Research 2002-002, 30 Pages, 2003/03
JAERI-Research-2002-002.pdf:1.42MB
no abstracts in English
*;
JNC TN9400 2000-047, 114 Pages, 2000/03
JNC-TN9400-2000-047.pdf:8.25MB
Prediction of weld residual stresses by a general finite element code is beneficial to the improvement of the accuracy of integrity assessment and residual life assessment of FBR plants. This reports develops an evaluation method of weld residual stresses using FINAS. Firstly, we suggested a basic procedure derived from parametric analyses with a simple weld joint model. The procedure can be summarized as follows: (1)For heat conduction analysis, prepare different models corresponding to the number of layers to be modeled. Hand over the analytical results to the following model. (2)Use multi-linear stress-strain curves for modeling the stress-strain response of base metal and weld metal. Use the isotropic hardening rule. (3)When metals are melt, use a user-subroutine to keep stresses from arising. (4)Put the thermal expansion coefficient as zero when heat is being input. Then, using the above procedure and TIG welding, we predicted the weld residual stresses of plate and tube. The results agreed well with the other reports, showing the suggested procedure was reasonable.
; *;
JNC TN9400 2000-045, 64 Pages, 2000/03
JNC-TN9400-2000-045.pdf:2.47MB
During the irradiation, the Pu redistribution phenomena would occur in the FBR MOX fuel pellets. The phenomena would considerably affect on the thermal properties of the fuels, therefore, it is need to establish the evaluation method for Pu redistribution phenomena. ln JNC, the efforts for development of the evaluation model for the phenomena had been continued and the simple evaluation model was constructed in 1992. In this work, the modification of the simple model developed in JNC has been done and the following results were obtained. (1)Based on the recent data of the MOX fuel irradiation tests, the evaluation model for Pu redistribution phenomena constructed in l992 is modified. And the model is included into the fuel performance analysis code "CEDAR". (2)To calibrate the modified CEDAR code, it is confirmed that the uncertainty in the Pu concentration evaluation for the center of the fuel pellet at EOL is about 
3wt.%. (3)Based on the results of the evaluations using the modified CEDAR code, it is found that, in the early stage of the irradiation, the Pu redistribution is controlled by the vapor transportation mechanism via pores, and after that, the Pu redistribution is kept in progress due to the thermal diffusion mechanism with the change of the Pu concentration due to the degradation of U and Pu by fissions. And it is also found that the O/M ratio dependence of the U-Pu inter diffusion coefficients would affect on the Pu redistribution mechanisms, in especial, in the early stage of the irradiation.
Futakawa, Masatoshi; *; Takada, Shoji;
Nuclear Technology, 118(1), p.83 - 88, 1997/04
Times Cited Count：1 Percentile：14.48(Nuclear Science & Technology)no abstracts in English
Futakawa, Masatoshi; Koizumi, Koichi; Shimizu, Katsusuke*; Takatsu, Hideyuki; ; *
JAERI-M 92-164, 58 Pages, 1992/11
no abstracts in English
Kawaguchi, Munemichi
no journal, ,
This study presents the fundamental research on the thermal decomposition behavior of sodium hydride (NaH) in FY2021. This study on the thermal decomposition behavior of NaH was carried out using TG-DTA and FT-IR for the decommissioning of the cold trap in Monju. Due to the weak ionic bonding of Na-H in NaH, the hydrogen is enable to move easily at close to 565K. Upon further heating, the hydrogen desorbs by the thermal decomposition. A simple model using each kinetic rate equations (
, 
, 
) can give us the quantitative evaluation of the thermal decomposition behavior of NaH, which tended to overestimated the Na evaporation.
