Structural evaluation of thermal stratification for PWR surge line

Yu, Y.J.; Park, S.H; Sohn, G.H.; Bak, W.J.

doi:10.1016/s0029-5493(97)00224-0

Cited by 28 publications

(10 citation statements)

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“…Development of computational fluid dynamics (CFD) model required to model the thermal condition of SL. There are many researchers contributed for CFD modeling of SL or similar component for modeling complex flow mixing and associated thermal stratification [50][51][52][53][54][55][56][57][58][59][60][61][62][63]. In this section we present a detailed parametric study of standalone CFD and coupled CFD and heat transfer (CFD-HT) analysis of SL.…”

Section: Cfd and Thermal-mechanical Stress Analysis Under Transient Cmentioning

confidence: 99%

“…The flow rate in SL varies according to plant operating procedures and can vary widely from plant to plant. A flow rate of 25-100 gpm is reported in the literature [50][51][52][53][54][55][56][57][58][59][60][61][62][63] We selected a similar flow rate for the parametric studies discussed in this section. To understand the effect of SL flow rate, stand-alone CFD simulations were performed with SL flow rates of 10 gpm, 50 gpm, 100 gpm, and 200 gpm.…”

Section: Effect Of Sl Mass Flow Ratementioning

confidence: 99%

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Final Report on CFD and Thermal-Mechanical Stress Analysis of PWR Surge Line under Transient Condition Thermal Stratification and an Evolutionary Cyclic Plasticity Based Transformative Fatigue Evaluation Approach without Using S~N Curve: Rev. 1

Mohanty

Barua

Listwan

et al. 2018

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This report presents an evolutionary cyclic plasticity based transformative approach for fatigue evaluation of safety critical components. This approach is generic which can be used not only for the present generation light water reactor components (which is our focus) but also for advanced reactor components. The approach is based on the fundamental concept of time-evolution of progressive fatigue damage rather than the end-of-life data based conventional S~N curve approaches. Series of fatigue tests on 316 stainless steel uniaxial specimens were conducted under strain-controlled and stress-controlled cyclic loading in two different environment such as in-air at 300 °C and PWR coolant water condition at 300 °C. Material models are developed to capture the uniaxial test data and are subsequently programmed into commercially available ABAQUS code to transform the uniaxial material behavior to multiaxial loading domain. The developed evolutionary cyclic-plasticity approach is verified by both analytical and 3D-FE modeling of uniaxial fatigue test specimens. Results show that the developed material models can capture the time-dependence of material hardening and softening with great accuracy. In addition, results show that the material models not only can capture the material behavior under constant amplitude loading but also can capture the load-sequence effect under variable and random amplitude loading. The ANL developed approach is one of its kind, which shows first in the fatigue research community that fatigue evaluation of a component (in our case verified for laboratory scale fatigue test specimens with great accuracy) can be performed for its entire fatigue life, including the hardening and softening behavior, without using a conventional S~N curve based approach.

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Section: Cfd and Thermal-mechanical Stress Analysis Under Transient Cmentioning

confidence: 99%

Section: Effect Of Sl Mass Flow Ratementioning

confidence: 99%

Final Report on CFD and Thermal-Mechanical Stress Analysis of PWR Surge Line under Transient Condition Thermal Stratification and an Evolutionary Cyclic Plasticity Based Transformative Fatigue Evaluation Approach without Using S~N Curve: Rev. 1

Mohanty

Barua

Listwan

et al. 2018

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“…This depends on the range of temperature transient, layout of pipe, type of fluid and its mixing behaviour. During PWRs and PHWRs start-up from cold condition, the max temperature difference (top and bottom part of pipe) could be as high as 200 [1]. Such a high temperature gradient along circumference cause high thermal stresses.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Thermal Stratification Induced Stress in Pipe and its Impact on Fatigue Design

Kumar

Jadhav

Gupta

et al. 2014

Procedia Engineering

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Thermal stratification is a phenomenon where a hot layer of fluid flows over a cold layer of fluid due to density difference. Thermal stratification is dominant in NPP piping where hot and cold fluids coexist or separated by a leaking valve. This phenomenon produces stresses in axial and tangential direction which causes damage during thermal cycling induced due to thermal stratification. These stresses produce additional damage during fatigue which is not incorporated in earlier plant piping design. This paper comprises a detail study of thermal stresses induced due to thermal stratification and its impact on fatigue life of piping. In this study the variation in support conditions are also analyzed along with their effect on the stress distribution of the pipe. The categorization of axial stress distribution is carried out with finite element model for a thermally stratified pipe. An analytical model for calculation of different thermal stress considering intermixing layer between hot and cold layer is formulated during a thermal stratification condition. The formulation is also validated with the results available in literature on thermal stratification. A case study for damage evaluation due to thermal stratification was carried out for a thermally stratified typical NPP surge line.

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“…Abou-산된 온도분포와 실험결과를 비교하고 열성층 시작점 을 예측하였다. (8) Yeom 등 (9,10) 은 급수배관 및 밀림배관 수평부에서의 2차원 열성층 유동 및 열전달 해석을 수행하였고, Yu 등 (11) 은 2차원 및 배관 요소를 이용한 유한요소해석을 통해 밀림배관에서의 온도분포와 변 위를 계산하였다. Jo 등은 유한체적법을 이용하여 유 사 배관에 대한 유동해석을 수행한 바 있으며, 이 때 곡선 비직교 격자망(curvilinear nonorthogonal mesh) 및 벽면 두께 고려 유무에 따른 영향을 분석하였다.…”

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Numerical Analyses to Simulate Thermal Stratification Phenomenon in a Piping System

Jeong¹,

Kim²,

Chang³

et al. 2009

Transactions of the Korean Society of Mechanical Engineers B

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In some portions of nuclear piping systems, stratification phenomena may occur due to the density difference between hot and cold stream. When the temperature difference is large, the stratified flow under diverse operating conditions can produce high thermal stress, which leads to unanticipated piping integrity issues. The objectives of this research are to examine controvertible numerical factors such as model size, grid resolution, turbulent parameters, governing equation, inflow direction and pipe wall. Parametric threedimensional computational fluid dynamics analyses were carried out to quantify effects of these parameters on the accuracy of temperature profiles in a typical nuclear piping with complex geometries. Then, as a key finding, it was recommended to use optimized mesh of real piping with the conjugated heat transfer condition for accurate thermal stratification analyses.

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Structural evaluation of thermal stratification for PWR surge line

Cited by 28 publications

References 0 publications

Final Report on CFD and Thermal-Mechanical Stress Analysis of PWR Surge Line under Transient Condition Thermal Stratification and an Evolutionary Cyclic Plasticity Based Transformative Fatigue Evaluation Approach without Using S~N Curve: Rev. 1

Final Report on CFD and Thermal-Mechanical Stress Analysis of PWR Surge Line under Transient Condition Thermal Stratification and an Evolutionary Cyclic Plasticity Based Transformative Fatigue Evaluation Approach without Using S~N Curve: Rev. 1

Evaluation of Thermal Stratification Induced Stress in Pipe and its Impact on Fatigue Design

Numerical Analyses to Simulate Thermal Stratification Phenomenon in a Piping System

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