RESULTS OF HDR-EXPERIMENTS FOR PIPE LOADS UNDER THERMALLY STRATIFIED FLOW CONDITIONS

During Phase II in of the HDR-Safety Program, 17 thermal stratification experiments (TEMR) were performed in a 6 m long, horizontal pipe section with 400 mm inside diameter. These experiments constituted the first, large-scale test program with close-to-realistic conditions on the issues of thermal shock, stratification and thermal striping. The examined system pressure ranged between 1 and 40 bar with the stagnant hot fluid temperatures between 100-degrees-C and 250-degrees-C, respectively, whereas the cold fluid temperature was kept about constant around 30-degrees-C. Special attention was given to the measurements of fluid and inside pipe surface temperature fluctuations. Prior to and upon completion of the experiments, various analytical activities evolved, covering all aspects of computer code simulations, stability analysis and assessments of the hydrodynamic, thermal and structural data. The HDR-TEMR data and related results received renewed international attention since the publications of U.S. Nuclear Regulatory Commission Bulletins No. 88-08 and 88-11. An overview is given on the major findings and highlights of the final data evaluation.