Revisiting large break LOCA with the CATHARE-3 three-field model

Valette, Michel; Pouvreau, Jérôme; Bestion, D.; Emonot, Philippe

doi:10.1016/j.nucengdes.2011.04.019

Cited by 32 publications

(11 citation statements)

References 8 publications

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“…Using (9), the R S of the top event fuzzy probability for the best estimate, lower bound and upper bound values are 0.010409, 0.003102 and 0.027792, respectively. Finally the best estimate, lower bound and upper bound probabilities to describe the failure of the top event can be generated using (8). Those three top event probabilities are ̅ -, and…”

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confidence: 99%

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A Fuzzy Probability Algorithm for Evaluating the AP1000 Long Term Cooling System to Mitigate Large Break LOCA

Purba

2016

Atom Indo.

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Components of nuclear power plants do not always have historical failure data to probabilistically evaluate their reliability characteristics. To overcome this drawback, an alternative approach has been proposed by involving experts to qualitatively justify basic event likelihood occurences. However, expert judgments always involve epistemic uncertainty and this uncertainty needs to be quantified. Existing fault tree analysis quantifies uncertainty using Monte Carlo simulation, which is based on probability distributions. Since expert judgments are not described in probability distributions, Monte Carlo simulation is not appropriate for evaluating epistemic uncertainty. Therefore, a new approach needs to be developed to overcome this limitation. This study proposes a fuzzy probability algorithm to evaluate epistemic uncertainties in fault tree analysis. In the proposed algorithm, fuzzy probabilities are used to represent epistemic uncertainties of basic events, intermediate events, and the top event. To propagate and quantify epistemic uncertainty in fault tree analysis, a fuzzy multiplication rule and a fuzzy complementation rule are applied to substitute the AND Boolean and OR Boolean gates, respectively. To see the feasibility and applicability of the proposed algorithm, a case-based experiment on uncertainty evaluation of the AP1000 long term cooling system to mitigate the large break loss of coolant accident is discussed. The result shows that the best estimate probability to describe the failure of AP1000 long term cooling system generated by the proposed algorithmis 3.15×10-11 , which is very closed to the reference value of 1.11×10-11. This result confirms that the proposed algorithm offers a good alternative approach to quantify uncertainties in probabilistic safety assessment by fault tree analysis.

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confidence: 99%

“…The AP1000 design is the first commercial nuclear power plant (NPP) design which implements passive safety systems [3]. Those (PWRs) [7,8]. The AP1000 design provides three passive safety systems to mitigate the large break LOCA, i.e.…”

Section: Introduction mentioning

confidence: 99%

A Fuzzy Probability Algorithm for Evaluating the AP1000 Long Term Cooling System to Mitigate Large Break LOCA

Purba

2016

Atom Indo.

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“…LOCA is defined as an accident in which reactor coolant pressure boundary breaks to freely discharge reactor coolant. LOCA which is caused by a large break in the primary coolant system is a design basis accident for pressurized water reactors [21].…”

Section: Ap1000 Passive Safety System To Mitigate a Large Break Locamentioning

confidence: 99%

Reliability Study of the AP1000 Passive Safety System by Fuzzy Approach

Purba

Tjahyani

2014

Atom Indo.

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“…The mist flow which enters the SG tubes is the result of this deposition and entrainment of droplets occurring first in the upper plenum and in the HL. Prediction of the resulting droplet flow rate entering SG tubes is of prime importance for modelling the so-called "steam-bindind" effect [10]. The vaporization of droplets in the hot SG tubes creates additional pressure losses in the loops which decreases the flooding rate in the core.…”

Section: Phenomena Of Interest In Hot Leg and Cold Leg Of A Pwrmentioning

confidence: 99%

“…Complex situations with totally different droplet and continuous liquid velocities may be better modelled with two separate velocities. In particular it was found that the transit time of droplets between the core and the steam generators during the Reflooding of a LBLOCA could play an important role in the steam binding process for the damping or not of gravity oscillations between core and donwncomer (Valette et al [10]). This transit time is not respected with the two-fluid model since the unique liquid velocity is an average between the droplet velocity and the continuous liquid velocity.…”

Section: Status Of the Dynamic Ia And Turbulence Modellingmentioning

confidence: 99%