Abstract
Integral test facilities (ITFs) are one of the main tools for the validation of best estimate thermalhydraulic system codes. The experimental data are also of great value when compared to the experiment-scaled conditions in a full NPP. The LOBI was a single plus a triple-loop (simulated by one loop) test facility electrically heated to simulate a 1300 MWe PWR. The scaling factor was 712 for the core power, volume, and mass flow. Primary and secondary sides contained all main active elements. Tests were performed for the characterization of phenomenologies relevant to large and small break LOCAs and special transients in PWRs. The paper presents the results of three posttest calculations of LOBI experiments. The selected experiments are BL-30, BL-44, and A1-84. They are LOCA scenarios of different break sizes and with different availability of safety injection components. The goal of the analysis is to improve the knowledge of the phenomena occurred in the facility in order to use it in further studies related to qualifying nodalizations of actual plants or to establish accuracy data bases for uncertainty methodologies. An example of procedure of implementing changes in a common nodalization valid for simulating tests occurred in a specific ITF is presented along with its confirmation based on posttests results.
Highlights
Experimental data recorded in integral test facilities (ITFs) are traditionally used in order to validate best estimate (BE) system codes and to investigate the behaviour of Nuclear Power Plants (NPPs) under accidental scenarios
The input deck used reflects as far as possible hardware configuration described in Section 2 and imposes initial, boundary conditions and set points shown in Table 2; one HPIS pump was used for the intact loop representing 2 of 4 pumps, one accumulator in the intact loop was simulated and cooldown of 100 K/h was adjusted to both Steam Generators (SG) experimental values
The results are in close agreement with experimental data and will become an interesting starting point for both future scaling calculations and accuracy evaluations
Summary
Experimental data recorded in integral test facilities (ITFs) are traditionally used in order to validate best estimate (BE) system codes and to investigate the behaviour of Nuclear Power Plants (NPPs) under accidental scenarios. Three different LOBI tests have been selected in order to be simulated They are all LOCA scenarios with break sizes between 5 and 10%. The objective of the test was to enrich the experimental database with a Counter Part Test having high value for code assessment and scalability, in particular with reference to the problem of initial power scaling in SB LOCAs. Phenomenological objectives were the identification of the mass distribution in the primary system (PS), loop seal behaviour, core heatup, and rewet and accumulator performance. Each relevant thermalhydraulic aspect appearing in more than one test has been identified and considered consistent when the expected behavior on the given test was in accordance with the explanation produced from the apparent differences in boundary conditions. Similarities and differences such as those depicted above have been carefully checked and unjustified distinctions strictly avoided
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
