This study investigated the behavior and environmental impact of expanded polystyrene (EPS) in a simulated marine environment, focusing on the effects of UV exposure. Through a series of controlled experiments, it was found that UV-induced weathering increased the formation of smaller EPS degradation products, leading to higher concentrations of dissolved organic carbon (DOC) in the seawater. Additionally, it was suggested that the assembly behavior of dissolved organic matter (DOM) contributed to the reduction of DOC levels over time. The EPS layer exhibited slightly higher DOC concentrations compared to the seawater, likely due to hydrophobic interactions that retained degradation products near the EPS. Analysis of the soil layer revealed that EPS particles and degradation products settled or adsorbed more extensively under UV conditions, indicating a greater risk of sediment contamination. Soil layer elution experiments further confirmed that EPS particles and their degradation products could migrate through soil pores, posing a potential contamination risk to other environments. UV exposure resulted in a twentyfold increase in DOC release from EPS compared to dark conditions. These findings highlight the persistent pollution potential of EPS in marine environments, especially under UV exposure, and emphasize the need for effective EPS waste management and further research into its environmental impacts.

Fatigue crack growth rate tests were conducted as a function of temperature, dissolved hydrogen (DH) level, and frequency in a simulated PWR environment. Fatigue crack growth rates increased slightly with increasing temperature in air. However, the fatigue crack growth rate did not change with increasing temperature in PWR water conditions. The DH levels did not affect the measured crack growth rate under the given test conditions. At 316 oC, oxides were observed on the fatigue crack surface, where the size of the oxide particles was about 0.2 μm at 5 ppb. Fatigue crack growth rate increased slightly with decreasing frequency within the frequency range of 0.1 Hz and 10 Hz in PWR water conditions; however, crack growth rate increased considerably at 0.01 Hz. The decrease of the fatigue crack growth rate in PWR water condition is attributed to crack closure resulting from the formation of oxides near the crack tips at a rather fast loading frequency of 10 Hz.

The most commonly used material of construction structures is steel. In this study, Epoxy-based coating materials and Ceramic-based coating materials durability were investigated. Exposed water immersion, chloride immersion, temperature changes, freezing and thawing for severe environments to simulate and environmental conditions are showed degraded in epoxy-based coating materials.