The advantage of the piezocone penetration test is a guarantee of continuous data, which are a source of reliable interpretation of the target soil layer. Much research has been carried out for several decades, and several classification charts have been developed to classify in situ soil from the cone penetration test result. Even though most present classification charts or methods were developed on the basis of data which were compiled over many countries, they should be verified to be feasible for local country. However, unfortunately, revision of those charts is quite difficult or almost impossible even though a chart provides misclassified soil class. In this research, a new method for developing soil classification model is proposed by using soft computing theory—fuzzy C-mean clustering and neuro-fuzzy theory—as a function of 5173 piezocone penetration test (PCPT) results and soil boring logs compiled from 17 local sites around Korea. Feasibility of the proposed soil classification model was verified from the viewpoint of accuracy of the classification result by comparing the classification results not only for data which were used for developing the model but also new data, which were not included in developing the model with real boring logs, other fuzzy computing classification models, and Robertson’s charts. The biggest advantage of the proposed method is that it is easy to make the piezocone soil classification system more accurate by updating new data.

The radiological impact of radionuclide transport via groundwater pathways at the Wolsong Low- and Intermediate-Level Waste (LILW) Disposal Center was estimated by considering site-specific characteristics, including hydrogeology, geochemistry, and land use. Human intrusion scenarios, such as groundwater well development, were analyzed to evaluate potential pumping volumes and radionuclide migration pathways. Particular attention was given to the hydrological and geochemical aspects of radionuclide transport, with a focus on local aquifer heterogeneity, flow dynamics, and interactions with engineered barriers and surrounding rock formations that delay radionuclide migration through sorption and other retention mechanisms. Sorption coefficients (K_d), calibrated using site-specific geochemical data, were incorporated to ensure realistic modeling of radionuclide behavior. A hierarchical approach integrating scenario screening, particle tracking techniques, and mass transfer modeling was employed. Numerical simulations using FEFLOW ver. 7.3 and GoldSim ver. 14.0 software provided insights into near-field and far-field transport phenomena under well pumping conditions. The results revealed distinct spatial flux behaviors, where carbon-14 (¹⁴C) dominated near-field flux due to its high inventory, while technetium-99 (⁹⁹Tc) emerged as the primary dose contributor in the far-field flux, owing to its anionic nature and limited sorption capacity. Additionally, under high-pH conditions near concrete barriers, cellulose degradation into isosaccharinic acid was identified, enhancing radionuclide mobility through complex formation. These findings underscore the importance of site-specific sorption and speciation parameters in safety assessment and highlight the need for accurate geochemical modeling to optimize waste placement and ensure long-term disposal safety. The outcomes provide valuable insights for optimizing waste placement and contribute to the development of evidence-based safety strategies for long-term performance assessment.