Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Takeda, Takeshi; Owada, Akihiko; Nakamura, Hideo
Experimental Thermal and Fluid Science, 51, p.112 - 121, 2013/11
Times Cited Count：12 Percentile：48.9(Thermodynamics)Kamiwaki, Tadayoshi; Owada, Akihiko; Takeda, Takeshi; Nakamura, Hideo
JAEA-Testing 2008-006, 77 Pages, 2008/07
JAEA-Testing-2008-006.pdf:6.32MB
Non-condensable gas for the pressurization of accumulator (ACC) tanks of emergency core cooling system may flow into the primary system during loss-of-coolant accidents (LOCAs) in a pressurized water reactor (PWR) after the ACC coolant injection is completed. Since the non-condensable gas may travel to and accumulates in steam generators (SGs) U-tubes, primary cooling and depressurization via SG secondary-side depressurization would become ineffective because of the degradation of condensation heat transfer in SG U-tubes. Since quantitative measurement of gas concentration is necessary to clarify the influences of non-condensable gas on the depressurization in ROSA/LSTF experiments that simulate PWR LOCAs and transients, an apparatus using a Zirconia oxygen sensor has been developed to directly measure the gas concentration in steam by introducing air as the non-condensable gas for the ACC pressurization. This apparatus is improved and applied to LSTF experiments where the gas concentration is measured directly in vessel upper head where gas may pass through with steam and in SG outlet plenum where gas accumulates. This report describes the improvement of the apparatus and the results of oxygen gas measurement characterization tests and the LSTF secondary-side depressurization experiments.
Takemoto, Masafumi; Nakamura, Hideo; Owada, Akihiko; Osaki, Hideki
JAEA-Research 2006-009, 48 Pages, 2006/03
JAEA-Research-2006-009.pdf:3.8MB
Nitrogen (N
)gas used for the pressurization of accumulator (ACC) tanks may flow into the PWR primary system during LOCAs after the ACC coolant injection is completed. Since N gas may travel to and accumulates in reactor vessel top and U-tubes in steam generators (SGs), primary cooling and depressurization via SG secondary-side depressurization would become ineffective because of the degradation of condensation heat transfer in SG U-tubes. Quantitative measurement of gas accumulation is necessary to clarify the influences of gas onto such degradation in the heat transfer and thus the primary depressurization. However, direct measurement method of non-condensable gas concentration in steam has not been established. An apparatus to directly measure gas concentration in high-temperature steam was developed to measure gas concentration in vessel upper head and SG U-tubes during LOCA experiments using ROSA/LSFT. The developed apparatus is primarily composed of zirconia oxygen sensor and turbine meter, enabling to deal with small amount of steam-gas mixture at high temperature when air is used to pressurize ACC tanks instead of N gas. This report describes the developed apparatus and its operation method with several test results for the confirmation of oxygen gas measurement capability and applicability of the apparatus to the ROSA/LSTF experiments.
Takei, Akihiko*; Owada, Hitoshi*; Fujita, Hideki*; Negishi, Kumi*; Hibiya, Keisuke*; Yokozeki, Kosuke*; Watanabe, Kenzo*
JNC TJ8400 2003-047, 120 Pages, 2003/02
JNC-TJ8400-2003-047.pdf:4.46MB
We acquired the water permeation properties and also mechanical characteristics of the altered specimen that produced by permeation or immersing as the fundamental data.
Takei, Akihiko*; Owada, Hitoshi*; Fujita, Hideki*; Negishi, Kumi*; Hibiya, Keisuke*; Yokozeki, Kosuke*; Watanabe, Kenzo*
JNC TJ8400 2003-046, 282 Pages, 2003/02
JNC-TJ8400-2003-046.pdf:8.26MB
We acquired the water permeation properties and also mechanical characteristics of the altered specimen that produced by permeation or immersing as the fundamental data.
Takei, Akihiko*; Owada, Hitoshi*; Fujita, Hideki*; Negishi, Kumi*
JNC TJ8400 2003-042, 67 Pages, 2003/02
TRU waste includes various chemical compounds such as nitrates. The influence of the chemical compounds on the performance of the barrier system should be estimated. In this study, we estimated the influence of sodium nitrate and also that of the chemical compounds derived from the sodium nitrate to the degradation of the cementitious material. 1) Evaluation of the influence of nitrate ion on the alteration of the cementitious material Alteration of characteristics of cementitious material was evaluated by the water permeation test using sodium nitrate solution. The calcium concentration of sodium nitrate solution permeated sample was higher than that of blank. The result indicates that sodium nitrate solution will accelerate the alteration of cementitious material. the permeation test was continued by using the ion-exchanged water as the permeation-water. As the results, the chemical and physical characteristics of the samples approached to those of blanks.2) Evaluation of the influence of ammonia on the alteration of the cementitious material Alteration of characteristics of cementitious material in nitrate and ammonia solution was evaluated by the water permeation test using 1mol/liter-sodium-nitrate and 0.5mol/liter-ammonia solution (denoted as NH-solution in the following). The calcium concentration of NH-solution permeated sample was higher than that of blank and the value of the calcium concentration was almost the same as that of the sodium nitrate solution case. The alteration range by the calcium leaching of the solid phase of the NH-solution case shows similar trend to that of the sodium nitrate solution case. The acceleration of the calcium dissolution was considered from this result. And the change of the water-permeability indicated the same trend with sodium-nitrate-solution case. From these results we confirmed that ammonia solution would not influence the alteration of cementitious solution.
Takei, Akihiko*; Owada, Hitoshi*; Fujita, Hideki*; Negishi, Kumi*
JNC TJ8400 2003-041, 152 Pages, 2003/02
JNC-TJ8400-2003-041.pdf:7.93MB
TRU waste includes various chemical compounds such as nitrates. The influence of the chemical compounds on the performance of the barrier system should be estimated. In this study, we estimated the influence of sodium nitrate and also that of the chemical compounds derived from the sodium nitrate to the degradation of the cementitious material. 1) Evaluation of the influence of nitrate ion on the alteration of the cementitious material Alteration of characteristics of cementitious material was evaluated by the water permeation test using sodium nitrate solution. The calcium concentration of sodium nitrate solution permeated sample was higher than that of blank. The result indicates that sodium nitrate solution will accelerate the alteration of cementitious material. the permeation test was continued by using the ion-exchanged water as the permeation-water. As the results, the chemical and physical characteristics of the samples approached to those of blanks. 2) Evaluation of the influence of ammonia on the alteration of the cementitious material Alteration of characteristics of cementitious material in nitrate and ammonia solution was evaluated by the water permeation test using 1mol/liter-sodium-nitrate and 0.5mol/liter-ammonia solution (denoted as NH-solution in the following). The calcium concentration of NH-solution permeated sample was higher than that of blank and the value of the calcium concentration was almost the same as that of the sodium nitrate solution case. The alteration range by the calcium leaching of the solid phase of the NH-solution case shows similar trend to that of the sodium nitrate solution case. The acceleration of the calcium dissolution was considered from this result. And the change of the water-permeability indicated the same trend with sodium-nitrate-solution case. From these results we confirmed that ammonia solution would not influence the alteration of cementitious solution.
; *; Owada, Hitoshi*; *; *
JNC TJ6400 2003-001, 44 Pages, 2003/02
JNC-TJ6400-2003-001.pdf:3.09MB
None
; *; Owada, Hitoshi*; *; *
JNC TJ6420 2002-007, 28 Pages, 2002/03
JNC-TJ6420-2002-007.pdf:0.38MB
None
*; Owada, Hitoshi*; Fujita, Hideki*; *
JNC TJ8400 2002-033, 60 Pages, 2002/02
JNC-TJ8400-2002-033.pdf:1.97MB
TRU waste includes various chemical compounds such as nitrates. The influence of the chemical compounds on the performance of the barrier system should be estimated. Since the temperature of the deep-underground is higher than that of the near surface and a part of the TRU waste generates the heat accompanied with the decay of the radioactive nuclides, the influences of the heat to the barrier material also should be taken into account. In this study, we estimated the influence of sodium nitrate and also that of the leachate from the ROBE-waste (borate-solidified body of concentrated low-level liquid waste) to the degradation of the cementitious material. We also obtained the mineralogical data of cementitious mineral after alteration in elevated temperature conditions. Results in this year are described below. (1)Alteration of characteristics of cementitious material in nitrate solution were evaluated by the water permeation test using sodium nitrate solution. The enhancement of the alteration of cementitious material due to sodium nitrate was observed. The dissolution quantity of the calcium of sodium nitrate solution permeated sample was larger than that of deionized water permeated sample (denoted as "blank" in following). Hydraulic conductivity of sodium nitrate solution permeated sample was lower than blank, but after changing permeation liquid from sodium nitrate solution to deionized water, hydraulic conductivity rose quickly. The increase of porosity and the decrease of compressive strength were observed in the case of sodium nitrate solution compared with blank. In the nitrate solution, sulfate type and carbonate type of AFm changed into the nitrate type AFm. The nitrate type AFm altered to the carbonate type AFm when the nitrate concentration was lowered. (2)The influence of the leachate from the two types of ROBE-waste on the dissolution of the cementitious material was evaluated by the leaching experiments. Dissolution of the calcium from the ...
*; Owada, Hitoshi*; Fujita, Hideki*; *; *; Yokozeki, Kosuke*; *
JNC TJ8400 2002-029, 79 Pages, 2002/02
JNC-TJ8400-2002-029.pdf:1.58MB
We acquired the water permeation properties and also mechanical characteristics of the altered specimen that produced by permeation or leaching as the fundamental data for the evaluation in "Study on the system development for evaluating long-term alteration of hydraulic field in Near Field" that had been carried out separately. The results in this year are shown below. (1)Hardened cement paste specimens with W/C=85% and 105% were altered and characterized after permeation. Permeability of altered part was increased, as permeated water increased. Porosity was increased at the upper part of altered specimens, and compressive strength that means the properties from altered part of specimens were decreased after water-permeation. Adequate correlations are estimated between compressive strength and porosity, permeability, Vickers hardness. From the chemical properties, it is presumed these physical changes were caused by dissolution of portlandite. (2)Hardened cement paste specimens with W/C=40 to 105% were immersed into deionized water and alteration behavior under diffusion condition was investigated. As a result, after 12 weeks, porosity was increasing and Vickers hardness was decreasing at the altered area. And the water permeability and the compressive strength at the deteriorated area were simulated from relations between water permeability, compressive strength, porosity, Vickers hardness and leaching ratio of calcium. These results suggest that two methods (permeation and leaching) make up for fault of each other. It is necessary to prepare additional data, to clarify the relations between each alteration factor.
*; Owada, Hitoshi*; Fujita, Hideki*; *; *; Yokozeki, Kosuke*; *
JNC TJ8400 2002-028, 218 Pages, 2002/02
We acquired the water permeation properties and also mechanical characteristics of the altered specimen that produced by permeation or leaching as the fundamental data for the evaluation in "Study on the system development for evaluating long-term alteration of hydraulic field in Near Field" that had been carried out separately. The results in this year are shown below. (1)Hardened cement paste specimens with W/C=85% and 105% were altered and characterized after permeation. Permeability of altered part was increased, as permeated water increased. Porosity was increased at the upper part of altered specimens, and compressive strength that means the properties from altered part of specimens were decreased after water-permeation. Adequate correlations are estimated between compressive strength and porosity, permeability, Vickers hardness. From the chemical properties, it is presumed these physical changes were caused by dissolution of portlandite. (2)Hardened cement paste specimens with W/C=40 to 105% were immersed into deionized water and alteration behavior under diffusion condition was investigated. As a result, after 12 weeks, porosity was increasing and Vickers hardness was decreasing at the altered area. And the water permeability and the compressive strength at the deteriorated area were simulated from relations between water permeability, compressive strength, porosity, Vickers hardness and leaching ratio of calcium. These results suggest that two methods (permeation and leaching) make up for fault of each other. It is necessary to prepare additional data, to clarify the relations between each alteration factor.
*; Owada, Hitoshi*; Fujita, Hideki*; *
JNC TJ8400 2002-020, 146 Pages, 2002/02
JNC-TJ8400-2002-020.pdf:4.21MB
TRU waste includes various chemical compounds such as nitrates. The influence of the chemical compounds on the performance of the barrier system should be estimated. Since the temperature of the deep-underground is higher than that of the near surface and a part of the TRU waste generates the heat accompanied with the decay of the radioactive nuclides, the influences of the heat to the barrier material also should be taken into account. In this study, we estimated the influence of sodium nitrate and also that of the leachate from the ROBE-waste (borate-solidified body of concentrated low-level liquid waste) to the degradation of the cementitious material. We also obtained the mineralogical data of cementitious mineral after alteration in elevated temperature conditions. Results in this year are described below. (1) Alteration of characteristics of cementitious material in nitrate solution were evaluated by the water permeation test using sodium nitrate solution. The enhancement of the alteration of cementitious material due to sodium nitrate was observed. The dissolution quantity of the calcium of sodium nitrate solution permeated sample was larger than that of deionized water permeated sample (denoted as "blank" in following). Hydraulic conductivity of sodium nitrate solution permeated sample was lower than blank, but after changing permeation liquid from sodium nitrate solution to deionized water, hydraulic conductivity rose quickly. The increase of porosity and the decrease of compressive strength were observed in the case of sodium nitrate solution compared with blank. In the nitrate solution, sulfate type and carbonate type of AFm changed into the nitrate type AFm. The nitrate type AFm altered to the carbonate type AFm when the nitrate concentration was lowered. (2) The influence of the leachate from the two types of ROBE-waste on the dissolution of the cementitious material was evaluated by the leaching experiments. Dissolution of the calcium ...
; *; Owada, Hitoshi*; *; *
JNC TJ6430 2002-002, 38 Pages, 2002/02
JNC-TJ6430-2002-002.pdf:2.33MB
None
Yonomoto, Taisuke; *; *; Anoda, Yoshinari; Kukita, Yutaka; ; Ito, Hideo; Osaki, Hideki; ; Nishikizawa, Tomotoshi; et al.
JAERI-M 94-069, 145 Pages, 1994/03
no abstracts in English
Kukita, Yutaka; Nakamura, Hideo; *; *; *; Anoda, Yoshinari; Kumamaru, Hiroshige; Suzuki, Mitsuhiro; ; Yonomoto, Taisuke; et al.
JAERI-M 91-040, 122 Pages, 1991/03
no abstracts in English
; Tasaka, Kanji; ; ; ; *
JAERI-M 83-105, 61 Pages, 1983/07
no abstracts in English
Nakamura, Hideo; Owada, Akihiko; Osaki, Hideki
no journal, ,
no abstracts in English
Owada, Akihiko
no journal, ,
no abstracts in English
