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The Mission of the Robotics and Remote Systems Division is to promote the development and application of immersive simulation, robotics, and remote systems for hazardous environments for the purpose of reducing hazardous exposure to individuals, reducing environmental hazards and reducing the cost of performing work.
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2024 ANS Annual Conference
June 16–19, 2024
Las Vegas, NV|Mandalay Bay Resort and Casino
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Latest News
Digital control system installed at China’s Linglong One
Earlier this month, the first digital control system was put in place at Linglong One, a small modular reactor demonstration project being built at the Changjiang nuclear power plant in Hainan Province. This is the world’s first land-based commercial SMR and is controlled by China National Nuclear Power Co. Ltd., a subsidiary of the China National Nuclear Corporation (CNNC).
Nitendra Singh, Arun Kumar Nayak, Parimal Pramod Kulkarni
Nuclear Technology | Volume 198 | Number 3 | June 2017 | Pages 306-318
Technical Paper | doi.org/10.1080/00295450.2017.1305764
Articles are hosted by Taylor and Francis Online.
Melt pool coolability is one of the concerns when addressing severe accident scenarios. Long-term cooling and stabilizing of highly radioactive and reactive molten corium are still issues to be addressed and understood in order to devise a successful handling strategy. Core catchers have been envisaged in present and future advanced reactors to manage this concern. In the ex-vessel core catcher scenario, corium relocates to form a molten pool. Injecting water from the bottom of this melt pool to achieve coolability is found to be an efficient technique so far. However, the numbers of tests with prototypic materials and conditions are very limited and difficult to perform. In view of this, most of the earlier studies have been conducted with simulated melts. There are concerns with regard to scalability of experiments, effects of melt composition, and geometric parameters on melt coolability. To address these issues, series of experiments have been conducted and are presented in this paper. The experiments are performed with borosilicate glass, with two melt volumes, i.e., 3 and 20 L, and are compared. They show that the melt quenching time was more or less the same and suggest that the results can be extrapolated to higher scales. Two different simulants were used in the experiments, i.e., sodium borosilicate glass and CaO-B2O3, to study the effect of melt composition, and it was observed that the coolability behavior remains the same but the melt quenching time varies. The effect of nozzle diameters was studied by conducting experiments with three different nozzle diameters of 8, 12, and 18 mm keeping the same inlet pressure. It was found that the quenching time was higher for the 8-mm-diameter nozzle experiment due to smaller flow rates compared to the others. The experiments were repeated at two inlet water pressures of 0.35 and 0.75 bar(g) for the same nozzle diameter to study their effects on melt coolability. As expected, the quenching time was found to be less for the case of higher inlet pressure. The experimental measurements suggest that the overall average melt pool coolability behavior under bottom flooding was almost the same in all cases. However, each physical parameter affects the melt quenching time required to cool the melt. This average melt quenching time can be optimized using suitable combinations of geometric and physical parameters. The debris sizes and porosities formed during the melt eruption were also measured. The measured porosities ranged between 50% and 60% in all experiments.