Application of the FSA scaling method to the LSTF ROSA 1.2 test and comparison to an application of the H2TS method

Antoine Ciechocki (1) , Sofia Carnevali (1) , Dominique Bestion (2) , Lionel Rossi (3)

1 STMF - Service de Thermo-hydraulique et de Mécanique des Fluides
2 Chercheur indépendant
3 LTHC - Laboratoire d'essais de Thermohydraulique et d'Hydromécanique analytique du Coeur et des circuits

The general objective of this work is to compare scaling methods and some different ways to apply them. In the present work, an application of the Fractional Scaling Analysis (FSA) method is compared to an application of the Hierarchical Two-Tiered Scaling (H2TS) method done by the Polytechnic University of Valence (UPV). The ROSA 1.2 test performed on the Japanese LSTF-ROSA-IV facility is analyzed. It is a 1% Hot Leg break LOCA. This transient is divided into five phases. Important bifurcating events are identified. A scaling analysis is applied to the first and the fourth phases called respectively the blowdown and the high-quality mixture discharge. The blowdown starts at the break opening while high-quality mixture discharge starts when primary and secondary pressures cross. The FSA methodology is applied at system and component scale by writing mass and pressure equations for two different control volumes, the primary system and the pressurizer. The CATHARE system thermal hydraulic code is used to calculate the effect metrics, scaling criteria specific to this method, which are analyzed and compared with the π-groups of the H2TS, obtained by the application of the UPV with the TRACE code. Differences between the results of the two methods are discussed. Moreover, the relative weight of the processes that control the pressure are evaluated. Some conclusions are drawn on the scaling and possible distortions of the test facility.

Mots clés: SB-LOCA; Scaling; LSTF; FSA; H2TS

Domaines: Mécanique des fluides [physics.class-ph]

Antoine Ciechocki, Sofia Carnevali, Dominique Bestion, Lionel Rossi. Application of the FSA scaling method to the LSTF ROSA 1.2 test and comparison to an application of the H2TS method. NURETH 19 - The 19th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, Mar 2022, Bruxelles, Belgium. ⟨cea-03818077⟩