Code validation and uncertainties in system thermalhydraulics

D'Auria, Francesco Saverio; Galassi, G. M.

doi:10.1016/s0149-1970(97)00097-8

Cited by 61 publications

(11 citation statements)

References 3 publications

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“…The application of complex codes is needed to discuss items (a) to (i): this requires the demonstration of capabilities for the numerical tools and the qualification (or V&V) for the generated calculation results, e.g. D'Auria & Galassi, 1998; unavoidable uncertainty evaluation is also involved, IAEA, 2008. Physicals aspects reflecting current understanding and assuming the availability of suitable computational tools are discussed in sections 3.1 to 3.6 (general level) and 4.1, 4.2 (Atucha-II specific).…”

Section: The Lbloca Elements (Pwr and Phwr)mentioning

confidence: 99%

The role of nuclear thermal-hydraulics in the licensing of Atucha-II: The LBLOCA

Mazzantini¹,

Galassi

D'Auria

2019

Nuclear Engineering and Design

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The paper deals with the safety evaluation and the embedded licensing process of the Atucha-II 800 Mwe Pressurized Heavy Water Reactor (PHWR) in Argentina. Atucha-II was designed by Kraftwerk Union (KWU) during the 60's, the related construction was started/stopped in the 90's and restarted on 2006, and was connected to the electrical grid in 2014. Because of market policies, the KWU designer could not be directly involved in the licensing process during the first decade of the 2000 millennium: a licensing suited safety evaluation was performed by the Nucleoeléctrica Argentina (NA-SA), utility owner of the Atucha-II, with support of external experts group. A designer-independent assessment was performed having access to the installed systems and components other than the relevant design documents. Large core size (related to Pressurized Water Reactor-PWR-producing the same thermal power), presence in the core of natural uranium and heavy water fluids, i.e. the coolant and the moderator driven by two circulation loops with different average temperatures, characterize the system design. In those conditions, during the early phase of a depressurization transient, the 'hot' coolant vaporizes and the colder moderator remains in the liquid phase: a positive void coefficient is created. The relevance of the Large Break Loss of Coolant Accident (LBLOCA) in safety assessment is discussed with emphasis given to the system design features, the approach pursued in the analysis and the key results. Break opening time and time of occurrence of the safety boron injection affect, during the early period of the transient, the propagation of (negative) pressure wave, the fluid flashing, the heat transfer and the neutron flux: a fission power excursion is expected to occur. The analysis of a complex three-dimensional situation, considering the unavoidable uncertainties associated with the computation, demonstrates that safety limits are preserved.

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Section: The Lbloca Elements (Pwr and Phwr)mentioning

confidence: 99%

The role of nuclear thermal-hydraulics in the licensing of Atucha-II: The LBLOCA

Mazzantini¹,

Galassi

D'Auria

2019

Nuclear Engineering and Design

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“…ref. [9], as a mandatory process to be completed before application of those computational tools to safety and licensing. In this context, the basis was set for addressing the scaling issue, e.g.…”

Section: -1980mentioning

confidence: 99%

Perspectives in System Thermal-Hydraulics

D'Auria¹

2012

Nuclear Engineering and Technology

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“…The model can reproduce a specific part or the whole system to be simulated. However as there is not a fixed rule to perform the nodalization, a large responsibility is passed to the user of the code in order to develop an adequate model scheme which makes best use of the various modules and the prediction capabilities of the specific code (Petruzzi and D'Auria, 2008;D'Auria and Galassi, 1998). Subchannel codes are used to analyse specific processes within the core of the reactor, such as localized flow and heat transfer variables in representative fuel assemblies.…”

Section: Thermal Hydraulic Modelingmentioning

confidence: 99%