Sb-loca. With boron dilution in pressurized water reactors, impact to the operation and safety
- Autores: Jordi Freixa Terradas
- Directores de la Tesis: Francesc-Josep Reventós Puigjaner (dir. tes.)
- Lectura: En la Universitat Politècnica de Catalunya (UPC) ( España ) en 2007
- Idioma: español
- Tribunal Calificador de la Tesis: Xavier Ortega Aramburu (presid.), Mª del Carmen Pretel Sánchez (secret.), Rafael Macian Juan (voc.), Lluís Batet (voc.), César Queral Salazar (voc.)
- Materias:
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- Resumen
After the Specialist Meeting on Boron Dilution Reactivity Transients held in State College (USA) in 1995 and organized by the Organization for Economic Cooperation and Development (OECD) in mutual effort with the Nuclear Energy Agency (NEA) and the Committee on the Safety of Nuclear Installations (CSNI), one of the main concerns of the international thermal-hydraulic community was to establish and analyse the capabilities of thermal-hydraulic codes to correctly simulate the phenomena involved in boron dilution transients.
Small-break loss-of-coolant accidents (SB-LOCA) enable the formation of low-borated slugs in the loop seals. Low-borated water, if driven to the core, could cause a reactivity excursion. Since online boron concentration measurement is impractical in the primary system of pressurized water reactor (PWR) plants and quite difficult in test facilities, best-estimate codes should be seen as the most suitable tools.
Soon after the discussions yielded in State College, experimental programs were started to study this kind of transients and its phenomenology. Among the projects carried out in the early 2000's, the experiments performed in the PKL test facility faced the issue from the most thermal-hydraulic point of view and were a good reference to validate and improve thermal-hydraulic codes.
The work brought out in the present PhD Thesis is mainly based on the participation in both the OECD/SETH and OECD/PKL projects that consisted among other issues on the experimental and simulation studies of SBLOCA with boron dilution transients in the PKL test facility. The participation of the Technical University of Catalonia (UPC) and the Institute of Energy Technologies (INTE) started with the development of a new nodalization with RELAP5 system code to simulate 5 different post-tests. The nodalization proved its capability to simulate most of the involved phenomena although, in some cases, 3-D capabilities appeared to be necessary in order to improve some
