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Acute oral toxicity and bioavailability of uranium and thorium in contaminated soil
Rashid Nur Shahidah Abdul,엄우용,Ijang Ibrahim,Khoo Kok Siong,SINGH BHUPENDRA KUMAR,Mahzan Nurul Syiffa,Fadzil Syazwani Mohd,Rodzi Nur Syamimi Diyana,Nasir Aina Shafinas Mohamad 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.4
A robust approach was conducted to determining the absolute oral bioavailable (fab) fractions of 238U and 232Th in rats exposed to contaminated soil along with their hematotoxicity and nephrotoxicity. The soil sample is the International Atomic Energy Agency-312 (IAEA-312) certified reference material, whereas blood, bones, and kidneys of in vivo female Sprague-Dawley (SD) rats estimate 238U- and 232Th-fab fractions post-exposure. We predict the bioavailable concentration (Cab) and fab values of 238U and 232Th after acute soil ingestion. The blood 238U (0.750%) and 232Th (0.028%) reach their maximum fab values after 48 h. The 238U (fab: 0.169–0.652%) accumulates mostly in the kidney, whereas the 232Th (fab: 0.004–0.021%) accumulates primarily in the bone. Additionally, 238U is more bioavailable than 232Th. Post 48 h acute ingestion demonstrates noticeable histopathological and hematological alterations, implying that intake of 238U in co-contaminated soil can lead to erythrocytes and proximal tubules damage, whereas, 232Th intake can harm erythrocytes. Our study provides new directions for future research into the health implications of acute oral exposures to 238U and 232Th in co-contaminated soils. The findings offer significant insight into the utilization of in vivo SD rat testing to estimate 238U and 232Th bioavailability and toxicity in exposure assessment.
Kamarudin Nur Anis Zulaikha,Ismail Aznan Fazli,Rabir Mohamad Hairie,Kok Siong Khoo 한국원자력학회 2024 Nuclear Engineering and Technology Vol.56 No.7
Effective management of slightly used nuclear fuel (SUNF) is crucial for both technical and public acceptance reasons. SUNF management, radiotoxicity risk, and associated financial investment and technological capabilities are major concerns in nuclear power production. Reducing the volume of SUNF can simplify its management, and one possible solution is utilizing small modular reactors (SMR) and advanced fuel designs like those with thorium. This research focuses on studying the neutronic performance and radionuclide inventory of three different thorium fuel configurations. The mass of fissile material in thorium-based fuel significantly impacts Kinf, burn-up, and neutron energy spectrum. Compared to uranium, thorium as a fuel produces far fewer transuranic elements and less long-lived fission products (LLFPs) at the end of the core cycle (EOC). However, certain fission product elements produced from thorium-based fuel exhibit higher radioactivity at the beginning of the core cycle (BOC). Physical separation of thorium and uranium in the fuel block, like seed-and-blanket units (SBU) and duplex fuel designs, generate less radioactive waste with lower radioactivity and longer cycle lengths than homogeneous or mixed thorium-uranium fuel. Furthermore, the SBU and duplex feel designs exhibit comparable neutron spectra, leading to negligible differences in SUNF production between the two.