Climate change has led to a significant increase in jellyfish populations globally, causing various problems. For power plants that use nearby seawater for cooling, the intrusion of jellyfish into intake systems can block the flow, leading to reduced output or even shutdowns. This issue is compounded by other small marine organisms like shrimp and salps, making it urgent to develop solutions to prevent their intrusion. This study addressed the problem using the BioSonics DT-X 120 kHz scientific fish finder to conduct preliminary tank experiments. We also deployed underwater acoustic and camera buoys around the intake of nuclear power plant, utilizing a bidirectional communication system between sea and land to collect data. Data collection took place from July 31, 2023 to August 1, 2023. While harmful organisms such as jellyfish and salps were not detected, we successfully gathered acoustic data on small fish measuring backscattering strength (SV). Analysis showed that fish schools were more prominent in the evening than during the day. The highest fish distribution was observed at 3:30 AM on July 31 with an SV of -44.8 dB while the lowest was at 12:30 PM on the same day with an SV of –63.4 dB. Additionally, a solar-powered system was used to enable real-time data acquisition from sea buoys with smooth communication between the land server and the offshore buoy located 1.8 km away. This research developed an acoustic-based monitoring system for detecting harmful organisms around the intake and provided foundational data for preventing marine organism intrusion and planning effective measures.

This study installed and evaluated the efficiency of a radon barrier membrane, radon mat, and radon well in the removal and reduction of radon gas that originates from the soil and flows indoors. The study aims to present a fundamental and long-term solution to radon reduction in buildings by preventing soil radon, which is the main source of radon gas, from migrating indoors. A radon barrier membrane, radon mat, and radon well were developed and verified, and the radon reduction effect of each system was evaluated. Through applying a special radon gas blocking film with a 5-layer structure, the radon barrier membrane prevents radon gas particles from passing through the polymer deposited on the radon blocking film. The radon mat is a type of radon reduction construction method that induces radon gas generated from the soil under the building to move in the desired direction through the plate-structured pressure reducing panel and discharges radon gas to the outside of the building through an exhaust pipe and fan installed at the edge. In addition, the radon well can also be applied to special structures such as old buildings and historical sites where it is difficult to directly reduce radon concentration within the building foundation, because the intake area can be controlled and, therefore, the method can be applied in a variety of environments and ranges. In the case of Intervention 1 (installing a radon barrier membrane and radon mat), the soil radon was reduced by 24.7%. Intervention 2 (installing a radon barrier membrane, radon mat, and radon well) reduced the soil radon by 45.1%, indicating that the effect of reducing the soil radon concentration was 1.8 times higher compared with installing only the radon barrier membrane and radon mat. The measurement showed that the indoor radon concentration was reduced by 46.5%, following the reduction in soil radon concentration through Interventions 1 and 2, demonstrating the effect of reducing indoor radon gas by installing the radon barrier membrane, radon mat, and radon well. Through the production and installation of prototype systems, this study confirmed the reduction effect of radon concentration in soil and indoor air. These systems achieved a higher efficiency at a relatively low cost than that achieved with the existing radon reduction methods applied in Korea and abroad.