Source term analysis should be carried out to prepare the decommissioning of the nuclear power plant. In the planning phase of decommissioning, the classification of decommissioning wastes and the cost evaluation are performed based on the results of source term analysis. In this study, the verification of MCNP/ORIGEN-2 model is carried out for preliminary source term calculation for Wolsung Unit 1. The inventories of actinide nuclides and fission products in fuel bundles with different burn-up were obtained by the depletion calculation of MCNPX code modelling the single channel. Two factors affecting the accuracy of source terms were investigated. First, the neutron spectrum effect on neutron induced activation calculation was reflected in one-group microscopic cross-sections of relevant radio-isotopes using the results of MCNP simulation, and the activation source terms calculated by ORIGEN-2 using the neutron spectrum corrected library were compared with the results of the original ORIGEN-2 library (CANDUNAU.LIB) in ORIGEN-2 code package. Second, operation history effect on activation calculation was also investigated. The source terms on both pressure tubes and calandria tubes replaced in 2010 and calandria tank were evaluated using MCNP/ORIGEN-2 with the neutron spectrum corrected library if the decommissioning wastes can be classified as a low level waste.

The aim of present study was to investigate the effect of three types of Chestnut Meals (CM) on chemical composition and rumen fermentation characteristics of the fermented diet. The inoculants consisted of Lactobacillus acidophilus, Bacillus subtilis, and Sacaromyces cerevisiae and were applied to three different types of CM; Whole Chestnut (WC), endodermis (EN), and kernel (KE). All types of CMs were ensiled at 39°C for 0, 1, 2, 4, or 6 days. After ensiling, the fermented CMs were sub-sampled for laboratory assays. On day six of fermentation, counts of the lactic acid-producing Bacillus subtilis, and yeast were higher (P<0.05) in WC than in the other CM types. On day four, KE had higher (P<0.05) crude protein content but lower (P<0.05) neutral detergent fiber and acid detergent fiber contents than the other treatments. In terms of rumen digestibility, KE had the highest (P<0.05) in vitro digestibility of dry matter (IVDMD), neutral detergent fiber digestibility (IVNDFD), total volatile fatty acid (VFA), propionate, butyrate concentrations, and total gas volume, as well as the lowest (P<0.05) acetate concentration. On the other hand, EN had the highest (P<0.05) pH and ammonia-N concentration in the rumen. In the rumen, even though WC application produced the highest microbial count and fermentation characteristics, it did not have a beneficial effect on rumen digestibility. Therefore, this study concluded that application of KE could be recommended due to the observed improvements in IVDMD and IVNDFD.