The contribution of UPTF experiments to resolve some scale-up uncertainties in countercurrent two phase flow

Glaeser, H.; Karwat, H.

doi:10.1016/0029-5493(93)90059-i

Cited by 24 publications

(2 citation statements)

References 3 publications

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“…), 1993]. CCFL in hot leg under reflux condenser conditions is described by Glaeser & Karwat, 1993, [10] The ratio mass flowrate / power generated (G/P) in each FA is given in Fig. 16.…”

Section: Background Analysis and Challengesmentioning

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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“…), 1993]. CCFL in hot leg under reflux condenser conditions is described by Glaeser & Karwat, 1993, [10] The ratio mass flowrate / power generated (G/P) in each FA is given in Fig. 16.…”

Section: Background Analysis and Challengesmentioning

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 ECC direct bypass fraction during the late reflood phase of a LBLOCA is strongly dependent on the break suction flow, downcomer cross flow from intact cold legs, and the geometrical configuration of the DVI nozzle and its location in the downcomer (T.S. , H. Glaeser, 1992,1993). In the current DVI system, the ECC bypass which occurs near the break suction flow is not controllable because the smooth downcomer wall has no resistance against the highly increased pressure difference of the break flow, and has no roles to prevent a high steamwater interaction near the break nozzle.…”

Section: Introductionmentioning

confidence: 99%