Most of the spent nuclear fuel generated by domestic nuclear power plants (NPPs) is temporarily stored in wet storage which is spent fuel pool (SFP) at each site. Currently, in case of Kori Unit 2, about 93.6% of spent nuclear fuel is stored in SFP. Without clear disposal policy determined for spent nuclear fuel, the storage capacity in each nuclear power plant is expected to reach saturation within 2030. Currently, the SFP stores not only spent fuel but also various non-fuel assembly (NFA). NFA apply to all device and structures except for fuel rods inserted in nuclear fuel assembly. The representative NFA is control element driving mechanism (CEDM), in-core instrument (ICI), burnable poison, and neutral resources. Although these components are irradiated in the reactor, they do not emit high-temperature heat and high radiation like nuclear fuel, so if they are classified as intermediate level waste (ILW) and low level waste (LLW) and moved outside the SFP, positive effects such as securing spent fuel storage space and delaying saturation points can be obtained. Therefore, this study analyzes the status of spent fuel and Non Fuel Assembly (NFA) storage in SFP of domestic nuclear power plants. In addition, this study predict the amount of spent fuel and NFA that occur in the future. For example, this study predicts the percentage of current and future ICIs and control rods in the SFP when stored in the spent fuel storage rack. In addition, the positive effects of moving NFA outside the SFP is analyzed. In addition, NFA withdrawn from SFP is classified as ILW & LLW according to the classification criteria, and the treatment, storage, and disposal methods of NFA will be considered. The study on the treatment, storage, and disposal methods of NFA is planned to be conducted by applying the existing KN-12 & KN-18 containers and ILW & LLW containers being developed for decommissioning waste.
Naegleria fowleri is pathogenic free-living amoeba leading to primary amoebic meningoencephalitis(PAM) in human and animals. The nfa1 gene cloned from N. fowleri is located on food-cup structure called pseudopodia and function an adherence of host target cells. To evaluate the effect of nfa1 vaccination against N. fowleri infection, we constructed retroviral vector(pQCXIN) expressing nfa1 gene. To determine the effect of vaccination and protective immunity in in vivo models, we measured the immunoglobulin levels, cytokine induction, and survival rate in mice infected with N. fowleri. Both levels of IgG and IgG subclass in DNA vaccinated mice were significantly elevated. The cytokine analysis show that DNA vaccinated mice induces production of IL-4 and IFN-γcytokines suggesting a Th1/Th2 mixed type immune response. The levels of nfa1 specific IgG antibody were maintained highly until 12 weeks post-vaccination in vaccinted mice. The nfa1 vaccinated mice using retroviral vector increased significantly survival rate(60%) after N. fowleri infection. Consequently, the nfa1 vaccination effectively induces protective immunity by upregulation of immune response in mice infected with N. fowleri. These results suggest that DNA vaccination using retroviral vector may be proper trial for treatment and prevention of PAM.