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Journal Articles

Experimental examination of heat removal limitation of screw cooling tube at high pressure and temperature conditions

Ezato, Koichiro; Suzuki, Satoshi; Dairaku, Masayuki; Akiba, Masato

Fusion Engineering and Design, 81(1-7), p.347 - 354, 2006/02

 Times Cited Count:10 Percentile:52.29(Nuclear Science & Technology)

no abstracts in English

JAEA Reports

Change in heat exchange performance of VCS cooler and its recovery works

Hamamoto, Shimpei; Watanabe, Shuji; Oyama, Sunao*; Ota, Yukimaru; Tochio, Daisuke; Fujimoto, Nozomu

JAERI-Tech 2005-035, 35 Pages, 2005/07

JAERI-Tech-2005-035.pdf:2.54MB

The Vessel Cooling System (VCS) is one of the safety engineered features of the HTTR. The VCS removes the decay heat of the reactor core when the forced circulation can not be maintained due to pipe rupture accidents, etc. VCS cools the core by water cooling panels surrounding the reactor pressure vessel. The VCS also keeps the temperature of the concrete of the primary shielding under the design limit during the operation. The temperature of cooling water of the VCS has recently tended to rise gradually, though the amount of heat removal of VCS has been constant. Accompanying with the increase of the cooling water temperature, the temperature of the shielding concrete is also possible to rise and exceed the limit. The heat exchange performance of the VCS cooler was evaluated and the deterioration of the cooler was verified. Therefore, the cleaning of heat transfer tubes was carried out to recover the heat exchange performance. The cleaning recovered the performance of the VCS cooler drastically and the cooling water temperature of the VCS could be reduced sufficiently.

JAEA Reports

Heat transfer characteristics evaluation of heat exchangers of mock-up test facility with full-scale reaction tube for HTTR hydrogen production system (Contract research)

Shimizu, Akira; Ohashi, Hirofumi; Kato, Michio; Hayashi, Koji; Aita, Hideki; Nishihara, Tetsuo; Inaba, Yoshitomo; Takada, Shoji; Morisaki, Norihiro; Sakaki, Akihiro*; et al.

JAERI-Tech 2005-031, 174 Pages, 2005/06

JAERI-Tech-2005-031.pdf:20.71MB

Connection of hydrogen production system by steam reforming of methane to the High Temperature Engineering Test Reactor (HTTR) of the Japan Atomic Energy Research Institute (JAERI) has been surveyed until now. Mock-up test facility of this steam reforming system with full-scale reaction tube was constructed in FY 2001, and a lot of operational test data on heat exchanges were obtained in these tests.In this report specifications, structures and heat transfer formulae of steam reformer, steam superheater, steam generator, condenser, helium gas cooler, feed gas heater and feed gas superheater were described. Evaluation codes were newly made to evaluate heat transfer characteristics from measured test data. Overall heat-transfer coefficient obtained from the experimental data were compared and evaluated with the prospective value calculated with heat transfer formulae. As a result, heat transfer performance and thermal efficiency of these heat exchangers were confirmed to be appropriate.

JAEA Reports

Experimental study on secondary depressurization action for PWR vessel bottom small break LOCA with HPI failure and gas inflow (ROSA-V/LSTF test SB-PV-03)

Suzuki, Mitsuhiro; Takeda, Takeshi; Asaka, Hideaki; Nakamura, Hideo

JAERI-Research 2005-014, 170 Pages, 2005/06

JAERI-Research-2005-014.pdf:7.64MB

A small break LOCA (SBLOCA) experiment was conducted at the LSTF of ROSA-V program to study effects of accident management (AM) on core cooling, which is important in case of high pressure injection (HPI) system failure during an SBLOCA at a PWR. The experiment, SB-PV-03, simulated ten instrument-tube break LOCA at the PWR vessel bottom equivalent to 0.2% cold leg break, total HPI failure, non-condensable gas inflow from accumulator injection system (AIS) and AM actions on secondary depressurization at -55 K/h and auxiliary feedwater (AFW) supply for 30 minutes. It was clarified that the AM actions were effective on primary depressurization until AIS injection end at 1.6 MPa, but thereafter became less effective by the gas inflow, resulting in low pressure injection (LPI) delay and whole core heatup under continuous water discharge at the break. The report describes these phenomena including core heatup related with primary coolant mass and AM actions, primary-to-secondary heat transfer analysis and estimation of gas in the primary loops.

Journal Articles

Development of ITER divertor vertical target with annular flow concept,1; Thermal-hydraulic characteristics of annular swirl tube

Ezato, Koichiro; Dairaku, Masayuki; Taniguchi, Masaki; Sato, Kazuyoshi; Suzuki, Satoshi; Akiba, Masato; Ibbott, C.*; Tivey, R.*

Fusion Science and Technology, 46(4), p.521 - 529, 2004/12

 Times Cited Count:6 Percentile:42.52(Nuclear Science & Technology)

Thermal hydraulic tests measuring critical heat flux CHF and pressure drop of an annular tube with twisted fin, "annular swirl tube", have been. This tube consists of two concentric tubes, the outer tube and the inner tube with a twisted fin on its outer surface. Cooling water flows inside of the inner tube first, and then returns into an annulus with a swirl flow at an end-return of the cooling tube. The CHF testing shows the no degradation of CHF of the annular swirl tube in comparison with the conventional swirl tube. A minimum axial velocity of 7.1m/sec is required for 28MW/m$$^{2}$$, the ITER design value. Applicability of the JAERI's correlation for the heat transfer to the annular swirl tube is also demonstrated by the comparison of the experimental results with those of the numerical analyses. The friction factor correlation for the annular flow with the twisted fins is made for the hydraulic designing of the vertical target. The least pressure drop at the end-return is obtained by using the hemispherical end-plug. Its radius is the same as that of ID of the outer cooling tube.

Journal Articles

Thermal fatigue experiment of screw cooling tube under one-sided heating condition

Ezato, Koichiro; Suzuki, Satoshi; Sato, Kazuyoshi; Akiba, Masato

Journal of Nuclear Materials, 329-333(1), p.820 - 824, 2004/08

 Times Cited Count:5 Percentile:36.97(Materials Science, Multidisciplinary)

This paper presents thermal fatigue experiments of a cooling tube with a helical triangular fin on its inner cooled surface, namely a ${it screw tube}$. The screw thread is directly shaped in a CuCrZr heat sink bar as a cooling channel. Slits with the width of 1.5 mm are machined at the heated side of the heat sink. The thermal fatigue experiments are carried out at 20 and 30 $$rm MW/m^2$$ by using an electron beam irradiation facility in JAERI. Water leakages from fatigue cracks, which locate at the slit of the heat sink, occurred at around 4500th and 1400th cycles at 20 and 30 $$rm MW/m^2$$, respectively. These results show good agreement with lifetime predictions using Manson-Coffin's law based on finite element analyses. Fractographic observations reveal that the fatigue cracks start from the outer heated surface at the slit region of the cooling channel and propagate toward its inner surface.

Journal Articles

Heat transfer characteristics of the steam reformer in the HTTR hydrogen production system

Takeda, Tetsuaki

Proceedings of 12th International Conference on Nuclear Engineering (ICONE-12) (CD-ROM), 4 Pages, 2004/00

no abstracts in English

JAEA Reports

Quantitative experiments on thermal hydraulic characteristics of an annular tube with twisted Fins

Ezato, Koichiro; Dairaku, Masayuki; Taniguchi, Masaki; Sato, Kazuyoshi; Suzuki, Satoshi; Akiba, Masato

JAERI-Tech 2003-084, 49 Pages, 2003/11

JAERI-Tech-2003-084.pdf:1.94MB

Thermal hydraulic tests measuring critical heat flux CHF and pressure drop of an annular tube with twisted fin, "annular swirl tube", have been. This tube consists of two concentric tubes, the outer tube and the inner tube with a twisted fin on its outer surface. Cooling water flows inside of the inner tube first, and then returns into an annulus with a swirl flow at an end-return of the cooling tube. The CHF testing shows the no degradation of CHF of the annular swirl tube in comparison with the conventional swirl tube. A minimum axial velocity of 7.1m/sec is required for 28MW/m$$^{2}$$, the ITER design value. Applicability of the JAERI's correlation for the heat transfer to the annular swirl tube is also demonstrated by the comparison of the experimental results with those of the numerical analyses. The friction factor correlation for the annular flow with the twisted fins is made for the hydraulic designing of the vertical target. The least pressure drop at the end-return is obtained by using the hemispherical end-plug. Its radius is the same as that of ID of the outer cooling tube.

Journal Articles

Heat transfer characteristics of gas heated type steam reformer

Takeda, Tetsuaki; Ohashi, Hirofumi; Inagaki, Yoshiyuki

Nihon Kikai Gakkai 2003-Nendo Nenji Taikai Koen Rombunshu, Vol.3, p.17 - 18, 2003/08

A technology development of a hydrogen production system by a nuclear heat are being performed as a heat application system of a high-temperature gas cooled reactor in the Japan Atomic Energy Research Institute. The objective of this study is to clarify heat transfer characteristics of the steam reformer in the HTTR hydrogen production system. An experiment has been performed using a double coaxial vertical tube to obtain the heat transfer characteristics and to evaluate the effectiveness of heat transfer enhancement. The amount of produced hydrogen increases with increasing not only reaction rate of catalysis but also the heat transfer coefficient. It is necessary to take into account of heat transfer from both surfaces of the double coaxial tube in order to obtain the amount of transferred heat from the heated tube to the coolant gas.

JAEA Reports

Development of ultrasonic heat transfer tube thickness measurement apparatus (Contract research)

Oba, Toshihiro; Suetsugu, Hidehiko*; Yano, Masaya*; Kato, Chiaki; Yanagihara, Takao

JAERI-Tech 2002-082, 47 Pages, 2003/01

JAERI-Tech-2002-082.pdf:1.87MB

The demonstration test for evaluating reliability of the acid recovery evaporator at Rokkasho Reprocessing Plant has been carried out at JAERI. For the nondestructive measurement of the thickness of heat transfer tubes of the acid recovery evaporator in corrosion test, we have developed thickness measurement apparatus for heat transfer tubes by ultrasonic immersion method with high resolution. The ultrasonic prove in a heat transfer tube can be moved vertically and radially. The results obtained by this apparatus coincident well with those obtained by a destructive method using an optical microscope.

Journal Articles

High heat load test of CFC divertor target plate with screw tube for JT-60 superconducting modification

Masaki, Kei; Taniguchi, Masaki; Miyo, Yasuhiko; Sakurai, Shinji; Sato, Kazuyoshi; Ezato, Koichiro; Tamai, Hiroshi; Sakasai, Akira; Matsukawa, Makoto; Ishida, Shinichi; et al.

Fusion Engineering and Design, 61-62, p.171 - 176, 2002/11

 Times Cited Count:17 Percentile:73.26(Nuclear Science & Technology)

A flat carbon fiber composite tile mock-up with screw tubes, which have helical fins like a nut, was fabricated aiming at further improvement of the heat removal performance of the cost-effectively manufactured divertor target for JT-60SC (modified JT-60 as a superconducting coil tokamak). The heat removal performance of the mock-up was successfully demonstrated on the JAERI Electron Beam Irradiation Stand. The estimated heat transfer coefficient of the screw tube at the non-boiling region was roughly 3 times higher than that of the smooth tube. This corresponds to 1.5 times that of the swirl tube. A heat cycle test of 10 MW/m2 showed that the mock-up with the screw tubes could withstand for 1400 cycles. These results indicate that the divertor target plate with the flat carbon fiber composite tile and the screw tube can be a promising candidate for the JT-60SC divertor target.

Journal Articles

Roll wave effects on annular condensing heat transfer in horizontal PCCS condenser tube

Kondo, Masaya; Nakamura, Hideo; Anoda, Yoshinari; Saishu, Sadanori*; Obata, Hiroyuki*; Shimada, Rumi*; Kawamura, Shinichi*

Proceedings of 10th International Conference on Nuclear Engineering (ICONE 10) (CD-ROM), 9 Pages, 2002/00

no abstracts in English

JAEA Reports

Inspection of heat transfer tubes after mock-up tests of minituarized apparatus for the acid recovery evaporator (Contract research)

Hamada, Shozo; Fukaya, Kiyoshi*; Kato, Chiaki; Yanagihara, Takao; Doi, Masamitsu*; Kiuchi, Kiyoshi

JAERI-Tech 2001-063, 49 Pages, 2001/10

JAERI-Tech-2001-063.pdf:13.39MB

The demonstration test for the acid recovery evaporator and the dissolver used in the major equipment of Rokkasho Reprocessing Plant (RRP), has been carried out. The mock-up miniature equipment has been employed to it. This test had been performed from April in 1998. The total time of demonstration test using the mock-up equipment is about two and half years, which corresponds to about 20,000 hours. After that, four of the seven heat transfer tubes used in the evaporator were drawn out and the corrosion level and the mechanical properties were evaluated for one of them. As a result, intergranular corrosion was recognized in the inner surface of the heat transfer tube and the corrosion depth at the grain boundary was statistically shown to be about one grain from the inner surface. Further, no change in mechanical properties was observed and growth of intergranular cracks in the inner surface of the specimen was found after flattering test.

Journal Articles

Experiments on heat transfer of smooth and swirl tubes under one-sided heating conditions

Araki, Masanori; Ogawa, Masuro; Kunugi, Tomoaki; Sato, Kazuyoshi;

Int. J. Heat Mass Transfer, 39(14), p.3045 - 3055, 1996/00

 Times Cited Count:57 Percentile:92.34(Thermodynamics)

no abstracts in English

Journal Articles

Experimental study on heat transfer characteristics of a high-temperature gas-gas heat exchanger with helically coiled tube bundles

Inagaki, Yoshiyuki; *; Ioka, Ikuo;

Proc. of ASME$$cdot$$JSME 4th Int. Conf. on Nuclear Engineering 1996 (ICONE-4), 1(PART B), p.633 - 637, 1996/00

no abstracts in English

Journal Articles

Structural design for intermediate heat exchanger of the HTTR

Kunitomi, Kazuhiko; Takeda, Takeshi; Shinozaki, Masayuki; Okubo, Minoru; *; Koikegami, Hajime*

Nihon Genshiryoku Gakkai-Shi, 37(4), p.316 - 326, 1995/00

 Times Cited Count:1 Percentile:18.1(Nuclear Science & Technology)

no abstracts in English

JAEA Reports

Stress and strain evaluation of the heat transfer tubes in the intermediate heat exchanger for the HTTR

Kunitomi, Kazuhiko; Shinozaki, Masayuki; ; Okubo, Minoru; Baba, Osamu; *; Otani, Akihito*

JAERI-M 92-147, 77 Pages, 1992/10

JAERI-M-92-147.pdf:1.77MB

no abstracts in English

Journal Articles

Thermosiphon double-wall-tube heat exchanger

Kumamaru, Hiroshige; *; Shimooke, Takanori; *; Kukita, Yutaka

Thermal Hydraulics of Advanced Heat Exchangers, p.31 - 37, 1991/00

no abstracts in English

19 (Records 1-19 displayed on this page)
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