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JAEA Reports

Development of ball bearing in high temperature water for in-vessel type control rod drive mechanism of advanced marine reactor

Nunokawa, Hiroshi*; Yoritsune, Tsutomu; Imayoshi, Sho*; Kasahara, Yoshiyuki*; Ochiai, Masaaki; Ishida, Toshihisa

JAERI-Tech 2001-040, 115 Pages, 2001/06

JAERI-Tech-2001-040.pdf:10.18MB

no abstracts in English

JAEA Reports

Flow-induced vibration measuremnts of ATR high-burnup fuel assembly

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PNC TN9410 97-013, 111 Pages, 1997/01

PNC-TN9410-97-013.pdf:5.85MB

Since the 54-rod cluster high-burnup fuel assemblies are planing to be loaded in Fugen, it must be confirmed that the mechanical integrity of the assemblies will be retained during the dwelling period in the reactor core. In the integrity verification, the confirmation that fretting wear, which occurs on fuel cladding surface at the contact with the spacer ring-elements, will not exceed the design margin is important. Accurate measurements of the flow-induced vibration characteristics under the hydraulic condition of coolant simulating the reactor core, especially measurements of the vibration amplitude, is necessary because the vibration amplitude directly affects the fretting wear depth. The flow-induced vibration measurements of the 54-rod cluster high-burnup fuels in which accelerometers were installed, were carried out under the various hydraulic conditions in the Component-Test-Loop (CTL). The results of the measurements are discribed in this papers. From the frequency analysis, the characteristic frequency of the fuel was observed around 105 Hz and 160 Hz. This frequency approximately coincided with that estimated by the fretting wear analysis code. The amplitude of flow-induced vibration was increased with increase in total flow rate and steam quality. Though these tendencies coincided with the results calculated by the analysis code, the amplitude measured at the region of low flow rate tended to be large compared with the calculated values. It was confirmed that this difference can be reduced on the safety side by the modification of the equation in the analysis code. The Paidoussis equation is divided into two terms in this modification, in which one term depending on total flow rate and the other term depending on steam quality, and proper coefficients are determined for each term. Though the amplitudes of flow-induced vibration for this fuel were larger than for either of the 28-rod cluster fuel of Fugen and 36-rod cluster fuel of ATR demonstration ...

JAEA Reports

None

Nogami, Yoshitaka; ;

PNC TN8410 96-218, 216 Pages, 1996/07

PNC-TN8410-96-218.pdf:9.24MB

None

JAEA Reports

None

Nogami, Yoshitaka; ; ; ;

PNC TN8410 96-214, 36 Pages, 1996/07

PNC-TN8410-96-214.pdf:1.47MB

None

JAEA Reports

Effects of the chemical decontamination on the component parts of the ATR fuel assembly

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PNC TN9410 96-235, 258 Pages, 1996/03

PNC-TN9410-96-235.pdf:41.18MB

The chemical decontamination technique has been developed in order to remove the crud adhering to the surface of the components constructing the primary coolant system, as a part of the measure to decrease the exposure in the annual inspection. The technique has been already applied to the prototype reactor "Fugen", in the core of which the fuel assemblies were not loaded. The chemical decontamination, for the core in which the fuel assemblies are loaded, has been planned for the purpose of improving the utilization factor. It is necessary to confirm, through the test before putting the plan into practice, that the decontamination reagent does not exert a bad influence upon the components constructing the fuel assembly. This report describes the test results which have been carried out so as to investigate the influence of the reagent on the components constructing the fuel assembly. The outline of the results is as follows: (1)The susceptibility to stress corrosion cracking of the chemical decontamination treatment and the residual decontamination reagent on the components constructing the fuel assembly is low enough. (2)The chemical decontamination treatment and the residual decontamination reagent do not exert a bad influence upon the integrity of the fuel assembly concerning the fuel rod holding function of the spacer and the characteristics of the fretting wear caused on the fuel claddings.

JAEA Reports