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Volume 23, Issue 5
Displaying 1-10 of 10 articles from this issue
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Hiroshi SEKIMOTO, Dae-Won LEE1986 Volume 23 Issue 5 Pages 381-386
Published: May 25, 1986
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSThe scalar neutron spectrum normalized in reference to unit source neutron was meas-ured with a miniature NE213 spectrometer at several positions along the centerline in a graphite-reflected lithium fluoride pile irradiated with D-T neutrons. The measured spectra were compared with the results of calculation using the MORSE-GG Monte Carlo code with the modified point-detector estimator and the GICXFNS group cross section set. The calculated spectrum near source neutron peak was less than the measured spectrum, and the discrepancy became larger with increasing penetration distance in the lithium fluoride region. The calculated spectrum was less than the measured spectrum below 4 MeV, especially in the graphite region.View full abstractDownload PDF (397K) -
Yoshiaki OKA, Chihiro TSUKISHIMA, Hiroyuki HASHIKURA, Masatsugu AKIYAM ...1986 Volume 23 Issue 5 Pages 387-394
Published: May 25, 1986
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSNeutron streaming in a very narrow and long stainless steel annulus which was 3 mm wide and 2, 480 mm long, was measured by TLDs and a neutron dose rate meter at the fast neutron source reactor YAYOI. The attenuation was very strong near the entrance and became very weak beyond 900 mm. The weak attenuation was due to the streaming of neu-trons through the annulus.
The two-dimensional discrete ordinates transport calculation with a forward biased S418 quadrature set failed to predict the attenuation beyond the point where the most-forward ray from the entrance intersected the wall of the annulus. It was practically impossible to analyze the streaming problem by the Sn code with more detailed Sn quadratures. The analytic expression describing the direct component agreed fairly well with the experiment far from the entrance of the annulus.View full abstractDownload PDF (516K) -
Masayoshi KAWAI, Michinori YAMAUCHI, Masaru NAKAI1986 Volume 23 Issue 5 Pages 395-403
Published: May 25, 1986
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSThe albedo data are important for use in solving the radiation streaming problem with albedo techniques, such as albedo Monte Carlo and albedo-Sn methods. This paper describes a method for calculating the energy-angle dependent doubly differential albedos for slab geomery with one-dimensional transport theory, based on the invariant imbedding method as well as the Sn method. Neutron albedo data calculated by the invariant imbedding method, are compared with those calculated by the Sn method and with the experimental data. It is found that the invariant imbedding method can be used to calculate the albedo data for a semi-infinitely thick slab several dozens of times faster than when using the Sn method. The calculated results have excellent agreement with the measured values.View full abstractDownload PDF (635K) -
Kiyoshi MATSUMOTO, Nobuo SHIMEGI, Atsuo KOHSAKA1986 Volume 23 Issue 5 Pages 404-414
Published: May 25, 1986
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSIt is very important to identify the reverse loss coefficient of BWR jet pump in the evaluation of core inlet flow at the beginning phase of BWR LBLOCA (Large Break Loss-of-Coolant Accident) analyses. Hence, the reverse flow property of jet pump was investi-gated in relation between the momentum equation, pressure loss coefficient and RELAP4 noding, and a new modeling has been proposed. In the proposed modeling, an equivalent pressure loss coefficient is used to take into account of the effect of accellerating pressure loss by the continuous flow area reduction from the tale pipe to the throat. The effective-ness of this model was studied by analyses for the LOFT 1/6 scale jet pump experiment and typical BWR LBLOCA. It has been, consequently, shown that this proposed model gives better jet pump property than a previous model which is used in the WREM sample problem and which gives very conservative result in core inlet flow and in the peak cladding tem-perature through whole transient.View full abstractDownload PDF (668K) -
Yutaka ABE, Makoto SOBAJIMA, Yoshio MURAO1986 Volume 23 Issue 5 Pages 415-432
Published: May 25, 1986
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSEmergency core cooling (ECC) water is carried up to the upper plenum and falls down again into the core during the reflood phase in PWR-LOCA. Therefore the quench front also propagates downward from the top of the core. The effect of upward steam flow rate on the top-down quench propagation was experimentally investigated. It was found that top-down quench velocity was delayed by upward steam flow. This effect is more significant when rod surface temperature is low and the falling water flow rate is small.
The effect of the flow rate and the rod temperature on the quench velocity was correlated based on the experimental results under the conditions of atmospheric pressure, saturation temperature for water and steam, rod surface temperature of 350600°C, down-ward water velocity of 0.01-0.1 m/s and upward steam velocity of 020 m/s.View full abstractDownload PDF (1008K) -
Derivation of Basic EquationsMotoaki OKAZAKI1986 Volume 23 Issue 5 Pages 433-450
Published: May 25, 1986
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSFor development of a two-phase flow analysis code by use of two-velocity two-temperature (2V2T) model, six basic equations completely independent and consistent with one another are derived for several possible types of thermodynamical unequilibrium conditions. Characteristic of the basic equations is that evaporation and condensation take place in the saturated water and saturated vapor separately. These phase change equations in the saturated state are rigorously derived using the thermodynamical law.
The energy conservation equation of each phase is derived from the well known total two-phase flow energy equation, using the first law of thermodynamics and conservation equations of mass and momentum of each phase. This derivation method will give assurance that all conservation equations are consistent with one another.
To form simplest 2V2T model, the terms of wall and interphase friction, and heat transfer to the two-phase flow and between phases are considered in this Dauer.View full abstractDownload PDF (1036K) -
Masanori YAMAKAWA, Takao SAKAI, Hiroaki KAWASHIMA, Akio SAKURAI, Sadao ...1986 Volume 23 Issue 5 Pages 451-460
Published: May 25, 1986
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSThe natural convection characteristics of gas in a vertical narrow annular gap which had its bottom opened to high temperature fluid and its upper shielding exposed to low temperature sealant have been evaluated from simulated fluid experiments using water and from calculations using the three-dimensional thermal hydraulic analysis computer code THERVIS-III. The following results were obtained :
(1) The critical Rayleigh number which represented the limit of convection generation increased as the aspect ratios ε1 (height/circumference) and ε2 (height/gap distance) increased.
(2) The flow pattern along the circumferential direction was seen to depend more strongly on the radiant heat from the side wall, rather than the aspect ratios ε1 and ε2.
(3) The temperature difference along the circumferential direction in the annular gap obtained from the calculation code coincided with that obtained from experiments within +10%, by taking account of a loss in gravitational head difference due to thermal conduction across the side wall which becomes a driving force for natural convection.View full abstractDownload PDF (592K) -
Hiroaki SUZUKI, Michio MURASE1986 Volume 23 Issue 5 Pages 461-468
Published: May 25, 1986
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSExperiments on countercurrent air-water flow were performed in two vertical channels with the same cross section as a BWR channel, but shorter channel length, which were interconnected with upper and lower plenums. Water and air were injected into the upper and lower plenums, respectively, and the air velocities in the two channels were measured. The air velocities differed in the two channels under the conditions where the differential pressure between the upper and lower plenums decreased with the increase in the air velo-city. The air velocity ratios between the two channels were calculated using measured single channel characteristics. The calculated results showed the same trends as the data.View full abstractDownload PDF (495K) -
Tadasumi MUROMURA, Takashi MURAKAMI, Mitsuo AKABORI1986 Volume 23 Issue 5 Pages 469-471
Published: May 25, 1986
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSDownload PDF (285K) -
Kozo GONDA, Shigehiko MIYACHI, Shoji FUKUDA1986 Volume 23 Issue 5 Pages 472-474
Published: May 25, 1986
Released on J-STAGE: April 18, 2008
JOURNAL FREE ACCESSDownload PDF (214K)
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