Fundamental study on cavitation erosion in liquid metal; Effect of liquid parameter on cavitation erosion in liquid metals (Joint research)

Hattori, Shuji*; Inoue, Fumitaka*; Kurachi, Hiroaki*; Watashi, Katsumi; Tsukimori, Kazuyuki; Hashimoto, Takashi; Yada, Hiroki

JAEA-Research 2008-080, 45 Pages, 2009/02

JAEA-Research-2008-080.pdf:2.86MB

Research on cavitation erosion in liquid metal is very important to confirm the safety of fast breeder reactor using sodium coolant. In this study, a cavitation erosion test apparatus was developed to carry out the erosion tests in low-temperature liquid metals. Cavitation erosion tests were carried out in liquid lead-bismuth alloy and in deionized water. We discuss the effect of liquid parameters and temperature effects on the erosion rate. We reach to the following conclusions. The erosion rate was evaluated in terms of a relative temperature which was defined as the percentage between freezing and boiling points. At 14 C relative temperature, the erosion rate is 10 times in lead-bismuth alloy, and 2 to 5 times in sodium, compared with that in deionized water. The erosion rate can be evaluated as a function of material density and sound velocity. Finally, the temperature dependence was discussed in term of liquid vapor pressure.

Development of Advanced Methodology for Defect Assessment in FBR Power Plants (Phase II)

Meshii, Toshiyuki*; Watashi, Katsumi; Doi, Motoo; Hashimoto, Takashi

JNC TY4400 2004-001, 90 Pages, 2004/03

JNC-TY4400-2004-001.pdf:10.67MB

Based on the results of the Phase I of the titled research, we started Phase II scheduled to reach conclusion (develop basic methods necessary for FBR post-construction code) in three years. The following results were obtained. (1) Development of assessment procedure for multiple defects due to creep damage: We first confirmed that multiple surface cracks in axial and circumferential direction inside a cylinder can be evaluated independently by investigating multiple flaws found in a cylinder due to cyclic thermal shock. Then we developed a method to evaluate the stress intensity factors (SIFs) of the multiple circumferential cracks in a finite legth cylinder under axisymmetric loads. (2) Improving creep-fatigue crack grown (C-FCG) assessment pfodedure: We reviewed the French code A16 for flaw assessment and compared it with the JNC proposal. Since the fundamenfal philosophy for both was to evaluate the C-FCG by estimating elastic-plastic fracture mechanics parameter from the SIF, we developed a "3D crack finite element analysis system that can specify the target error in SIF." (3) Crack propagation assessment under thermal stresses (fatigue crack grown (FCG) resistace for small load): To improve accuracy of FCG assesment for components in FBR power plants (designed to minimize thermal stresses) under thermal cycles, we obtained near threshold FCG data for S55C, SUS304, HT60, SS400, 2.25Cr-1Mo, SUS316, SUS321, T91, Inconel718 by Kmax = constant test method. The results showed that FCG curves in the JSME post construction code (which is an extrapolation of the curves in ASME PVP code sec. XI) are valid in general. However, precise review of S55C, HT60's data suggested that the JSME FCG, evaluation curve may not have enough safety margin. In addition, we proposed a method to predict the decrease in the threshold SIF range DeltaKth due to high Kmax and showed its validity.

Effect of liquid parameter on cavitation erosion in liquid metals

Hashimoto, Takashi; Hattori, Shuji*; Inoue, Fumitaka*; Watashi, Katsumi

no journal, , 

Research on cavitation erosion in liquid metal is very important problem to confirm the safety of the fast breeder reactor using sodium coolant and to solve the problem of cavitation erosion in a liquid-mercury target of spallation neutron source. In this study, the cavitation erosion test apparatus was developed to carry out in liquid metals at low temperatures. Erosion tests of SUS304 were carried out in lead-bismuth and deionized water. Mass loss was measured at various liquid temperatures in lead-bismuth and deionized water.