The Experts below are selected from a list of 2361 Experts worldwide ranked by ideXlab platform

Kenji Tominaga - One of the best experts on this subject based on the ideXlab platform.

  • Experimental Study on Performance of a Hybrid Baffle Plate for the Water-Wall-Type Passive Containment Cooling System
    Nuclear Technology, 1995
    Co-Authors: Fujii Tadashi, Yoshiyuki Kataoka, Michio Murase, Kenji Tominaga
    Abstract:

    A water-wall-type passive containment cooling system, which has an outer pool (O/P) outside the suppression pool (S/P), is one passive safety system for the next generation reactors. It utilizes the steel containment vessel wall as a heat transfer medium between the S/P and O/P. As a measure to improve heat removal capability, the authors propose introduction of a Baffle Plate. The Baffle Plate can mitigate thermal stratification and enlarge the high-temperature region in the S/P. In particular, a hybrid Baffle Plate utilizes the structure wall by setting up local flow holes and enhances the natural circulation in the S/P through these holes. To clarify the effects of the configurations of the flow holes, thermal-hydraulic behavior has been examined. 1. The circumferential temperature difference in the outside region of the Baffle Plate was 20%. 3. The maximum efficiency was obtained when the ratio of the depth between the vent tube outlet and the lower flow holes to the height between the vent tube outlet and the upper flow holes was ∼ 0.7.

  • Thermal hydraulics of an external water wall type passive containment cooling system
    Nuclear Technology, 1995
    Co-Authors: Yoshiyuki Kataoka, Tadashi Fujii, Michio Murase, Kenji Tominaga
    Abstract:

    An external water wall type containment cooling system is one of the passive containment cooling systems that use no active components and are intended for system simplification in the next generation power reactors. The core decay heat during a postulated loss-of-coolant accident is accumulated in the suppression pool (SP) and transferred to the outer pool, which is a cooling pool located outside and adjacent to the SP, by only natural phenomena such as natural convection, heat conduction, and evaporation. The temperature profiles and the convection heat transfer coefficients in the pools were measured using a 5-m height apparatus. The formation of a thermal stratification boundary at the vent outlets, which restricts the effective heat transfer area between pools, was clarified, and a correlation for natural convection heat transfer coefficients was obtained. Condensation heat transfer coefficients on the containment vessel wall and evaporation heat transfer coefficients on the SP surface under a noncondensable gas presence, which strongly affected the heat removal from the wet well, were evaluated based on the test results, and the correlations were obtained. The heat removal evaluation models, which analyze the trends of the temperatures and pressure, were developed and verified with system tests. As for themore » improvement of heat removal capability, two methods were proposed. One is a Baffle Plate to mitigate thermal stratification in the SP and enlarge the effective heat transfer area between pools. The second method is a divided wet well to avoid noncondensable gas effects. The thermal-hydraulic behavior in the SP with a Baffle Plate was clarified by three-dimensional analysis, and the effectiveness of these methods was experimentally confirmed.« less

Yoshiyuki Kataoka - One of the best experts on this subject based on the ideXlab platform.

  • Experimental Study on Performance of a Hybrid Baffle Plate for the Water-Wall-Type Passive Containment Cooling System
    Nuclear Technology, 1995
    Co-Authors: Fujii Tadashi, Yoshiyuki Kataoka, Michio Murase, Kenji Tominaga
    Abstract:

    A water-wall-type passive containment cooling system, which has an outer pool (O/P) outside the suppression pool (S/P), is one passive safety system for the next generation reactors. It utilizes the steel containment vessel wall as a heat transfer medium between the S/P and O/P. As a measure to improve heat removal capability, the authors propose introduction of a Baffle Plate. The Baffle Plate can mitigate thermal stratification and enlarge the high-temperature region in the S/P. In particular, a hybrid Baffle Plate utilizes the structure wall by setting up local flow holes and enhances the natural circulation in the S/P through these holes. To clarify the effects of the configurations of the flow holes, thermal-hydraulic behavior has been examined. 1. The circumferential temperature difference in the outside region of the Baffle Plate was 20%. 3. The maximum efficiency was obtained when the ratio of the depth between the vent tube outlet and the lower flow holes to the height between the vent tube outlet and the upper flow holes was ∼ 0.7.

  • Thermal hydraulics of an external water wall type passive containment cooling system
    Nuclear Technology, 1995
    Co-Authors: Yoshiyuki Kataoka, Tadashi Fujii, Michio Murase, Kenji Tominaga
    Abstract:

    An external water wall type containment cooling system is one of the passive containment cooling systems that use no active components and are intended for system simplification in the next generation power reactors. The core decay heat during a postulated loss-of-coolant accident is accumulated in the suppression pool (SP) and transferred to the outer pool, which is a cooling pool located outside and adjacent to the SP, by only natural phenomena such as natural convection, heat conduction, and evaporation. The temperature profiles and the convection heat transfer coefficients in the pools were measured using a 5-m height apparatus. The formation of a thermal stratification boundary at the vent outlets, which restricts the effective heat transfer area between pools, was clarified, and a correlation for natural convection heat transfer coefficients was obtained. Condensation heat transfer coefficients on the containment vessel wall and evaporation heat transfer coefficients on the SP surface under a noncondensable gas presence, which strongly affected the heat removal from the wet well, were evaluated based on the test results, and the correlations were obtained. The heat removal evaluation models, which analyze the trends of the temperatures and pressure, were developed and verified with system tests. As for themore » improvement of heat removal capability, two methods were proposed. One is a Baffle Plate to mitigate thermal stratification in the SP and enlarge the effective heat transfer area between pools. The second method is a divided wet well to avoid noncondensable gas effects. The thermal-hydraulic behavior in the SP with a Baffle Plate was clarified by three-dimensional analysis, and the effectiveness of these methods was experimentally confirmed.« less

Michio Murase - One of the best experts on this subject based on the ideXlab platform.

  • Experimental Study on Performance of a Hybrid Baffle Plate for the Water-Wall-Type Passive Containment Cooling System
    Nuclear Technology, 1995
    Co-Authors: Fujii Tadashi, Yoshiyuki Kataoka, Michio Murase, Kenji Tominaga
    Abstract:

    A water-wall-type passive containment cooling system, which has an outer pool (O/P) outside the suppression pool (S/P), is one passive safety system for the next generation reactors. It utilizes the steel containment vessel wall as a heat transfer medium between the S/P and O/P. As a measure to improve heat removal capability, the authors propose introduction of a Baffle Plate. The Baffle Plate can mitigate thermal stratification and enlarge the high-temperature region in the S/P. In particular, a hybrid Baffle Plate utilizes the structure wall by setting up local flow holes and enhances the natural circulation in the S/P through these holes. To clarify the effects of the configurations of the flow holes, thermal-hydraulic behavior has been examined. 1. The circumferential temperature difference in the outside region of the Baffle Plate was 20%. 3. The maximum efficiency was obtained when the ratio of the depth between the vent tube outlet and the lower flow holes to the height between the vent tube outlet and the upper flow holes was ∼ 0.7.

  • Thermal hydraulics of an external water wall type passive containment cooling system
    Nuclear Technology, 1995
    Co-Authors: Yoshiyuki Kataoka, Tadashi Fujii, Michio Murase, Kenji Tominaga
    Abstract:

    An external water wall type containment cooling system is one of the passive containment cooling systems that use no active components and are intended for system simplification in the next generation power reactors. The core decay heat during a postulated loss-of-coolant accident is accumulated in the suppression pool (SP) and transferred to the outer pool, which is a cooling pool located outside and adjacent to the SP, by only natural phenomena such as natural convection, heat conduction, and evaporation. The temperature profiles and the convection heat transfer coefficients in the pools were measured using a 5-m height apparatus. The formation of a thermal stratification boundary at the vent outlets, which restricts the effective heat transfer area between pools, was clarified, and a correlation for natural convection heat transfer coefficients was obtained. Condensation heat transfer coefficients on the containment vessel wall and evaporation heat transfer coefficients on the SP surface under a noncondensable gas presence, which strongly affected the heat removal from the wet well, were evaluated based on the test results, and the correlations were obtained. The heat removal evaluation models, which analyze the trends of the temperatures and pressure, were developed and verified with system tests. As for themore » improvement of heat removal capability, two methods were proposed. One is a Baffle Plate to mitigate thermal stratification in the SP and enlarge the effective heat transfer area between pools. The second method is a divided wet well to avoid noncondensable gas effects. The thermal-hydraulic behavior in the SP with a Baffle Plate was clarified by three-dimensional analysis, and the effectiveness of these methods was experimentally confirmed.« less

Fujii Tadashi - One of the best experts on this subject based on the ideXlab platform.

  • Experimental Study on Performance of a Hybrid Baffle Plate for the Water-Wall-Type Passive Containment Cooling System
    Nuclear Technology, 1995
    Co-Authors: Fujii Tadashi, Yoshiyuki Kataoka, Michio Murase, Kenji Tominaga
    Abstract:

    A water-wall-type passive containment cooling system, which has an outer pool (O/P) outside the suppression pool (S/P), is one passive safety system for the next generation reactors. It utilizes the steel containment vessel wall as a heat transfer medium between the S/P and O/P. As a measure to improve heat removal capability, the authors propose introduction of a Baffle Plate. The Baffle Plate can mitigate thermal stratification and enlarge the high-temperature region in the S/P. In particular, a hybrid Baffle Plate utilizes the structure wall by setting up local flow holes and enhances the natural circulation in the S/P through these holes. To clarify the effects of the configurations of the flow holes, thermal-hydraulic behavior has been examined. 1. The circumferential temperature difference in the outside region of the Baffle Plate was 20%. 3. The maximum efficiency was obtained when the ratio of the depth between the vent tube outlet and the lower flow holes to the height between the vent tube outlet and the upper flow holes was ∼ 0.7.

G.n. Tiwari - One of the best experts on this subject based on the ideXlab platform.