No abstract available

[en] The stress states that lead to failure of joints between Glidcop^TM CuAl25 and 316L SS were examined using finite element modeling techniques to explain experimental observations of behavior of those joints. The joints were formed by hot isostatic pressing (HIP) and bend bar specimens were fabricated with the joint inclined 45 deg. to the major axis of the specimen. The lower surface of the bend bar was notched in order to help induce a precrack for subsequent loading in bending. The precrack was intended to localize a high stress concentration in close proximity to the interface so that its behavior could be examined without complicating factors from the bulk materials and the specimen configuration. Preparatory work to grow acceptable precracks caused the specimen to fail prematurely while the precrack was still progressing into the specimen toward the interface. The finite element model demonstrated maximum stress concentrations in the interface layer to be shifted off-center. An additional benefit from the finite element modeling effort was in understanding if the stress states in this non-conventional specimen were representative of those that might be experienced in practice

[en] On a two-dimensional lattice, the SU(2) gauge theory coupled to an unflavored fermion is formulated suitably for a Hamiltonian Monte Carlo calculation. This involves propagation through gauge-invariant states defined so that all transitions have positive amplitudes. The vacuum energy and the mass of the lightest baryon are discussed

[en] The purpose of this study is to understand the influence of green rust on the migration of iodide. GR(CT) would be major corrosion product of iron near the seawater or saline layer in underground. The GR(CT) may play an important role in the retardation of the iodide migration in a deep geological environment due to it's anionic exchange reaction. In underground radioactive waste repository, the corrosion of iron canisters would be proceed as follows; Fe(II) and/or Fe(III) dissolved from iron containers → Fe(II)(OH)₂ and/or Fe(III)(OH)₃ → Green rust → Lepidocrocite or Magnetite → Goetite etc. Generally, the green rust has known to exist in environments close to the Fe(Π)/Fe(ΠΙ) transition zone or between the oxidized layer and reduced layer in the underground. As anion exchanger and strong reducer, the green rusts can affect the migration of anions, reactions involving green rusts were poorly studied in relation to the safety assessment of radioactive waste repository

[en] The powder characteristics and sinterability were investigated with the powder milled after OREOX treatment and the powder only OREOX-treated without milling. The powder was prepared from the simulated spent fuel. In the case of 1 cycle OREOX-treated powder, the particle has relatively large size and very irregular shape with a number of macro-cracks. With repeating of the OREOX treatment cycle, the macro-cracks changed to micro-cracks and the particle size decreased. Powders having less than 1 μm of average particle size could be obtained by milling the OREOXed powders regardless of the cycle number. The sound pellets with higher than 95% T.D. of sintered density and larger than 8μm of grain size were made with the powder milled after 1 cycle of OREOX treatment. The powder milled for short time after 3 cycle of OREOX treatment also produced the pellets with higher than 95% T.D. of sintered density and larger than 8 μm of grain size. It could be concluded that the sintered density and grain size of DUPIC pellets are greatly influenced by milling process

[en] We study chiral symmetry of SU(2) Yang-Mills theory coupled to an unflavored fermion on a two-dimensional lattice using a hybrid algorithm based on the projector Hamiltonian Monte Carlo method. The correlation functions of a chiral condensate and of fermion occupation number are calculated. We find chiral-symmetry breaking in the continuum limit. The theory is calculated to reside in only one phase in which chiral symmetry is broken

[en] Se-79 has emerged as one of the most frequently considered nuclides in the safety assessments of high level radioactive waste disposal, especially in the disposal of pyro-process wastes, due to its long half life (t_1/2 = 3.0x10⁵∼1.1x10⁶ years). While selenium naturally exists in four different oxidation states, -2, 0, +4 and +6, selenium is likely to exist as .2, 0 and/or +4 in an underground. In a Korean concept, a canister containing high-level radioactive wastes or spent fuel would be installed in a cylindrical bentonite block placed in a borehole located deep underground. After corrosion of canister, the selenium ions released from waste materials will be contacted with bentonite. In this study, the sorption phenomenon of selenium ion onto bentonite has been examined

[en] The stress states that lead to failure of joints between GlidCop trademark CuAl25 and 316L SS were examined using finite element modeling techniques to explain experimental observations of behavior of those joints. The joints were formed by hot isostatic pressing (HIP) and bend bar specimens were fabricated with the joint inclined 45 degree to the major axis of the specimen. The lower surface of the bend bar was notched in order to help induce a precrack for subsequent loading in bending. The precrack was intended to localize a high stress concentration in close proximity to the interface so that its behavior could be examined without complicating factors from the bulk materials and the specimen configuration. Preparatory work to grow acceptable precracks caused the specimen to fail prematurely while the precrack was still progressing into the specimen toward the interface. This prompted the finite element model calculations to help understand the reasons for this behavior from examination of the stress states throughout the specimen. An additional benefit sought from the finite element modeling effort was to understand if the stress states in this non-conventional specimen were representative of those that might be experienced during operation in ITER

[en] For the performance evaluation of the DUPIC fuel fabrication technology, largescale in-cell experiments were conducted using kilogram quantities of natural UO₂ powder and the equipment installed in the M6 hot cell at IMEF (Irradiated Material Examination Facility). As part of the fabrication process development, granulation was attempted with the roll-compacting technique, which is found unsuitable for remote operation in hot cell due to the sensitivity of the process parameters to the granule properties. In each experiments, the powders and pellets produced were characterized to investigate the relationship between the process parameters and the properties of the products. The UO₂-based DUPIC pellets having a sintered density of 95%TD (Theoretical Density) and average grain size of 5.4μm, meeting CANDU specifications, were fabricated successfully. The process flow and process parameters to fabricate DUPIC pellets were established. Consequently the fabrication technology and the performance of the equipment developed for DUPIC fuel pellet were verified

[en] Guidelines for the optimal management of patients with cervical cancerous nodes from an unknown primary site, has not been yet settled. However, radical treatment has been advocated employing either a surgery, or radiotherapy, or a combination of the two in relation to the location, stage and histologic features of the nodes in the neck. Of 43 patients who presented with 'Cervical metastases from an unknown primary' since 1971, 31.2% survived 3 years after adequate management. Combined modality with surgery and radiation showed more favorable treatment results: in local control rate, 3 year survival rates and the subsequent appearances of the contralateral side of neck node through the retrospective analysis. In 11 cases, the primary tumors became apparent later, carcinoma of the hypopharynx, being the most frequent site, rather than the nasopharynx