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Volume 23, Issue 2
Displaying 1-11 of 11 articles from this issue
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Hideshi FUKUMOTO1986 Volume 23 Issue 2 Pages 97-109
Published: February 25, 1986
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSA new method and an accompanying computer code CINAC have been developed for the calculation of neutron-induced transmutation, radioactivity and afterheat. In the method, the generation and depletion of nuclides during and after reactor operation are described in a matrix form in which the arrangement of nuclides is determined systematically. The solutions are obtained by an eigenvalue analysis of the matrix without any time steps or iterative schemes which would increase the computational time. The method can treat any type of activation chains equally, and it gives analytical solutions for linear chains. The CINAC code, coupled with the radiation transport codes ANISN and DOT3.5, can also calculate the dose distribution at any time after shutdown in a one- or two-dimensional geometry of fusion reactors. Two calculations were carried out using CINAC to confirm its validity. The results were compared to those calculated by the THIDA code system which is based on a matrix exponential method. The new method was 50 times faster than the latter, while the discrepancy between them was 4% at the most.View full abstractDownload PDF (765K) -
Characteristics of Residual Two-Phase Pool in Upper PlenumHideo NAGASAKA, Masaru KATOH, Nobuaki ABE, Hideto AOKI, Tatsuo KAGAWA1986 Volume 23 Issue 2 Pages 110-122
Published: February 25, 1986
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSIn the first report of this study, dealing with CCFL and CCFL breakdown phenomena associated with the injection of emergency core cooling spray water into upper plenum dur-ing refill-reflood phase of a BWR LOCA, the following tests results were obtained. The injected water maintained two-phase pool across the top of entire core after CCFL breakdown. The pool level oscillated near spray elevation. The objective of this paper is to clarify the mechanism of these phenomena, evaluating steam and spray flow effects on CCFL breakdown. It is found that when spray flow rate was slightly larger than the CCFL drainage deter-mined by core steam flow, pool maintained at some constant level near spray elevation, after CCFL breakdown. On the other hand, when spray flow was appreciably larger than CCFL drainage, pool level slowly oscillated. The oscillation was caused by significant changes in steam condensation rate, and the corresponding subcooling penetration into the fuel bundles, when the pool level passed the spray elevation. The TRAC-BD1 analysis of test results suggested the small sector wall effect of test apparatus on CCFL breakdown phenomena.View full abstractDownload PDF (702K) -
Takamichi IWAMURA, Hiromichi ADACHI, Makoto SOBAJIMA1986 Volume 23 Issue 2 Pages 123-135
Published: February 25, 1986
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSTwo-dimensional effects on the core cooling behavior during the reflood phase of a PWR-LOCA were experimentally studied by performing four tests with various radial core power profiles under the same total power and initial core stored energy conditions using the Slab Core Test Facility (SCTF). The heat transfer was enhanced and the cladding temperature was reduced for the higher and average power bundles in the steep radial power profile test especially at the upper elevation. The effect of radial power profile on the cladding temperature was quantitatively evaluated. For all tests with different radial power profiles, the collapsed water level in the upper plenum became higher in the hot leg side and the quench in the upper half of the core was delayed in the bundles corresponding to the outer bundles of a PWR core. The delay of the quench is considered to be caused by a flow stagnation trend in those bundles because the pressure in the outer bundles be-came higher than the pressure in the inner bundles due to the nonuniform water accumula-tion in the upper plenum.View full abstractDownload PDF (742K) -
Tadashi NARABAYASHI, Kenji ARAI, Takashi KUBOKOYA, Osamu AMANO, Toshie ...1986 Volume 23 Issue 2 Pages 136-150
Published: February 25, 1986
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSIn the event of a LOCA (loss-of-coolant accident) resulting from a hypothetical guillo-tine break in the suction line of the PLR (primary loop recirculation) pump for a BWR plant, the PLR pump will be reversely driven by the two-phase fluid flowing back at high speed in the line. For clarifying the two-phase flow characteristics of the PLR pump, which would be necessary for the analysis of pump behavior during LOCA, blowdown tests were conducted using three scale model pumps. The two-phase flow characteristics data for the pump were plotted with use of homologous curves method and the two-phase degradation multiplier in order to examine the effect of specific speed and void fraction. As a result of this study, it was shown that the characteristics of any pump with specific speed between Ns=500 and 4, 200 rpm•gpm1/2/ft3/4 can be obtained by interpolation. Experimental analyses were made using the TRAC code. Analytical results regarding pump inlet pressure, void fraction, volumetric flow rate and pump speed showed good agreement with the test results. This is a joint study of Japan BWR utilities and plant makers.View full abstractDownload PDF (838K) -
Yasuo HARAYAMA, Masahiko KYOYA1986 Volume 23 Issue 2 Pages 151-159
Published: February 25, 1986
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSA hollow pellet is proposed as fuel for high performance fuel rods. It is difficult, dur-ing pellet fabrication, to accurately center the hole in the pellet. A fabrication tolerance must be allowed for the center of the hole and that of the pellet. The present paper seeks to analytically obtain the temperature and heat flux distribu-tion in a fuel rod containing pellets with eccentric holes. The temperature distribution in power reactor fuel, based on practical assumption, can be obtained within reasonable limits by solving the steady-state heat conduction equation for the pellets with eccentric holes. The solution is simple, and appropriate to fuel design or safety evaluation.View full abstractDownload PDF (510K) -
Hiroshi UJITA, Kazuo TAKARAGI, Hidesuke MATSUSHIMA1986 Volume 23 Issue 2 Pages 160-167
Published: February 25, 1986
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSA plant reliability analysis method using both prime implicant sets in an event tree and minimal cut sets in a fault tree is developed for probabilistic safety assessment. The method can evaluate not only common mode failures in different systems, but also phased mission analysis problems in different phases. Applicability of the method is confirmed for phased mission analysis problems taking the FBR plant decay heat removal system as an example.View full abstractDownload PDF (417K) -
Kazuaki YANAGISAWA1986 Volume 23 Issue 2 Pages 168-175
Published: February 25, 1986
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSA study was made on an incubation burn-up for fission gas release using fuel swelling microstructural analysis. Conclusions of the study are : (1) The fuel microstructural analysis successfully determined the incubation burn-up. The analyzed values agreed with those estimated by the Halden empirical gas release model. (2) The incubation burn-up obtained from the Halden model was correlated with the fuel center temperature, but the micro-structural analysis was more dependent on the local fuel swelling temperature. (3) The incubation burn-up was attributed to the grain boundary diffusion process and the fuel local gaseous swelling.View full abstractDownload PDF (556K) -
Makoto TAKANO, Kazuhiro SAWA1986 Volume 23 Issue 2 Pages 176-178
Published: February 25, 1986
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSDownload PDF (201K) -
Yasumasa IKEZOE, Kaoru ONUKI, Hayato NAKAJIMA, Shoichl SATO, Tomoo NAK ...1986 Volume 23 Issue 2 Pages 179-181
Published: February 25, 1986
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSDownload PDF (212K) -
Toshikazu TAKEDA, Takafumi AOYAMA, Akira HASEGAWA, Yasuyuki KIKUCHI1986 Volume 23 Issue 2 Pages 181-184
Published: February 25, 1986
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSDownload PDF (223K) -
Ryosho KUWAE, Minoru OBATA, Kanemitsu SATO, Seishi SHIMA1986 Volume 23 Issue 2 Pages 185-187
Published: February 25, 1986
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSDownload PDF (174K)
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