One-dimensional model for containment in AP1000 nuclear power plant based on thermal stratification

Thermal stratification phenomena in piping systems of nuclear power plant would threaten the structural integrity of pipes, which are caused by the significant change of water density with temperature. To provide temperature gradients for the stress analysis of Normal heat Removal System (RNS) suction line of a Gen-III nuclear power plant, the relevant thermal stratification phenomena are analyzed by CFD in this paper. Cases without leakage (normal power operation) and with leakage are both studied. The results show that the first portion of pipe (one meter or so) near the hot leg is isothermal for normal power operation due to the penetrating flow. In the remaining portion, the radial temperature drops are of the order of 20∼27 K for no leakage case. For the leakage case, the radial temperature drops are 23 K or less, which are relatively smaller than those for the no leakage case due to the net hot flow from the hot leg to the valve.

Download Full-text

One-Dimensional Seismic Soil Response at the Nuclear Power Plant of Kashiwazaki-Kariwa during the 2007 Niigata-Chuetsu-Oki Earthquake

Proceedings of the Fifteenth International Conference on Civil, Structural and Environmental Engineering Computing ◽

10.4203/ccp.108.157 ◽

2015 ◽

Author(s):

F. Gatti ◽

F. Lopez-Caballero ◽

D. Clouteau

Keyword(s):

Power Plant ◽

Nuclear Power Plant ◽

Nuclear Power ◽

Soil Response ◽

One Dimensional

Download Full-text

Thermal Stratification Analysis and Fatigue Evaluation for Pressurizer Surge Line in Nuclear Power Plant

Volume 2: Plant Systems, Structures, Components and Materials ◽

10.1115/icone25-67118 ◽

2017 ◽

Author(s):

Xiao Xu ◽

Pan Liu ◽

Guihe Zhang ◽

Dasheng Wang ◽

Ting Jin

Keyword(s):

Power Plant ◽

Nuclear Power Plant ◽

Thermal Stratification ◽

Nuclear Power ◽

Influence Factors ◽

One Dimension ◽

Three Dimension ◽

Penetration Length ◽

Surge Line ◽

Fatigue Evaluation

Thermal stratification of pressurizer surge line in nuclear power plant induced by the stratification of fluid results in additional stresses (system-dependent and system-independent stresses). These additional stresses are related to the thermal stratification distribution, such as temperature difference, stratification location, stratification length and boundary layer slope and thickness. This thermal stratification distribution is effected by several parameters such as turbulent penetration length and surge line slope. These influence factors are studied with numerical method. For the additional stresses, this study theoretically establishes the solution of the system-dependent stresses according to the thermal stratification distribution assumption. With the system-dependent and system-independent stresses, a complex three-dimension problem is simplified into a one-dimension. Using this effective one-dimension method, fatigue evaluation can be fast processed and accurate improved in engineering analyses.

Download Full-text

Experimental Investigation Into Thermal Stratification by Direct Condensation in a Scaled Suppression Pool of Fukushima Daiichi Nuclear Power Plant

Volume 2A: Thermal Hydraulics ◽

10.1115/icone22-30090 ◽

2014 ◽

Cited By ~ 1

Author(s):

Byeongnam Jo ◽

Shinji Takahashi ◽

Daehun Song ◽

Wataru Sagawa ◽

Nejdet Erkan ◽

...

Keyword(s):

Power Plant ◽

Nuclear Power Plant ◽

Flow Rate ◽

Thermal Stratification ◽

Nuclear Power ◽

Experimental Results ◽

Steam Condensation ◽

Wide Range ◽

Fukushima Daiichi ◽

Suppression Pool

Experimental and numerical studies into thermal stratification by direct steam condensation in a torus type suppression pool were carried out to investigate the reactor core isolation cooling in the accidents of Fukushima Daiichi nuclear power plants. The suppression pool was manufactured to be a 1/22 scaled model of a Fukushima Daiichi nuclear power plant. Two different types of spargers were employed to simulate different units of the plants. In a sparger, 132 holes were uniformly drilled on the side of a pipe. However, the other sparger injected steam to the bottom. Flow rate was varied in a wide range to examine the effect on thermal stratification in the suppression pool. The experimental results showed that the sparger type influenced formation of thermal stratification. Moreover, steam flow rate strongly affected the onset time of thermal stratification, and the disappearance of the thermal stratification was affected by subcooling temperature. Computer simulation using a commercial software was conducted and the results show similar temperature profiles to the experimental results. Steam condensation was visualized in a vicinity of the spargers using high speed camera.

Download Full-text