[en] In order to precisely measure the dimensions of the CANDU fuel bundles in atmosphere or water, a fuel inspection system was developed. The LVDT was used as measuring sensor in this system. An LVDT calibration equipment was also developed in order to satisfy the required accuracy of the system. And, polynomial functions were introduced to calibrate the LVDT and to eliminate mechanical systematic errors. The accuracy of the fuel inspection system was examined. The results show that the accuracy in dimensional measurement of fuel rod profile and bearing pad profile, diameter of fuel bundle, fuel rod length, and end plate profile using standard test equipment satisfies the design criteria, i.e., maximum measurement error of 0.01mm(10 μm)

[en] The ab-plane thermal conductivity of single-crystalline hexagonal MgB₂ has been measured as a function of magnetic field with orientations both parallel and perpendicular to the c-axis and at temperatures between 0.5 and 8 K. The observed anomalous variation of the thermal conductivity in magnetic fields at constant temperature is consistent with a field-induced suppression of two superconducting energy gaps of significantly different magnitude. An anomalous nonlinear temperature dependence of the electronic thermal conductivity, violating the Wiedemann-Franz law, is observed in the field-induced normal state

[en] We present results of the optical reflectivity in the basal-plane of the hexagonal MgB₂ superconductor. The data were collected on a mosaic of MgB₂ single crystals with T_c=38 K from the ultraviolet down to the far infrared (FIR) as a function of temperature as well as of magnetic field oriented along the c-axis. In the FIR there is a clear signature of the superconducting gap with a gap-ratio 2Δ/k_BT_c∼1.2, well below the weak-coupling value. The gap is suppressed in an external magnetic field, which is a function of temperature. We extract the upper critical field H_c2 along the c-axis

[en] This paper describes the thermalhydraulic characteristics of CANDU-6 reactors' fuel channel loaded with CANFLEX-RU (CANDU Flexible Fuelling - Recycled Uranium) bundles. The NUCIRC code, recently updated with the pressure drop and critical heat flux(CHF) models of CANFLEX bundle, is used to evaluate the thermalhydraulic characteristics of the CANFLEX-RU fuel channel such as the distributions of channel flow rate, channel exit quality, Critical Channel Power(CCP) and Critical Power Ratio(CPR). This paper also examines the effects of pressure tube creep and bearing pads height on the thermalhydraulic characteristics. The distributions of channel flow rate and CCP for CANFLEX-RU fuel channel show the typical thermalhydraulic characteristics of CANDU-6 reactor channel, and the CPR keeps greater than 1. 455. Considering the pressure tube creep for CANFLEX-RU bundle, the decrease of the CCP for CANFLEX-RU fuel channel is less than that for 37-element natural uranium fuel channel. Raising bearing pads height from 1.4 mm to 1.8 mm, the CCP enhancement is estimated to be about 2%

[en] Large conductivity increases under 21 K electron or neutron irradiations are observed in SmS and SmSsub(1-x)Psub(x). It is shown that they are related to Sm defects. A possible mechanism is 4f electron delocalization around radiation defects. In SmB₆, the low temperature resistivity increase desappears under 21 K irradiation. The thermal stability of the defects is also investigated up to room temperature

[en] This document is a report on the safety assessment for the 24 CANFLEX-NU(CANDU Flexible fuelling - Natural Uranium) fuel bundle demonstration irradiation at Wolsong-1 Generating Station. The CANFLEX fuel bundle as a CANDU advanced fuel has been jointly developed by KAERI/AECL. This document describes the rationale for the demonstration irradiation and comments on the Korean government licensing issues such as the status of the CANFLEX fuel irradiations at NRU research reactor in AECL, status and plan of the CANFLEX fuel irradiations at a CANDU-6 power reactor, status of the water CHF(Critical Heat Flux) test at Stern Laboratories and the CHF correlation. This documents presents an assessment the consequences of postulated accidents with all safety system available during demonstration irradiation of 24 CANFLEX-NU fuel bundles at Wolsong-1 Generating Station. The assessment is made by two kinds of approaches. One approach is based on the document of the safety assessment for the 24 CANFLEX-NU fuel bundle demonstration irradiation at Point Lepreau Generating Station. The other approach is taken from the safety analyses using the analysis methods and assumptions used in the final safety reports on the 600 MWe CANDU-PHWR Wolsung-2, 3, and 4 Nuclear Power Plants for the Korea Electric Power Cooperation. The analyses are not comprehensive reviews of the postulated accidents, but examination of the expected difference in accident consequences because of the presence of 24 CANFLEX fuel bundles in two channels. The approach is to compare the difference to the safety margin for 37-element bundle cases

[en] We report on measurements of the magnetic moment in superconducting MgB₂ single crystals by SQUID magnetometry. Neutron irradiation is employed to modify the defect structure. We show that both the reversible as well as the irreversible properties are significantly affected by irradiation. The upper critical field and the irreversibility line are strongly enhanced for H_a parallel c and the critical current density shows a very pronounced fishtail

[en] We present small-angle neutron scattering (SANS) measurements of the vortex lattice (VL) in single crystal MgB₂--a two-band superconductor. Bragg diffraction of neutrons visualizes the structure and orientation of the VL while the scattered intensity probes the super-carrier density. Superconductivity in the π-band is rapidly suppressed with increasing field with a corresponding decrease in scattered intensity and a re-orientation of the VL between 0.5 and 0.9 T. Both these observations are consistent with superconductivity in the π-band being weaker than in the σ-band (Δ_π<Δ_σ), and a changing influence of different parts of the Fermi surface determining the VL orientation. SANS measurements of the VL for fields applied at an angle to the c-axis allow the penetration depth anisotropy, γ_λ, to be estimated

[en] Korea Ministry of Science and Technology(MOST) has pushed and given a financial support to a KEPRI/KAERI Joint Industrialization Program of CANFLEX-NU Fuel as one of Korea's National Nuclear Mid- and Long Term R and D Program. The Industrialization Program will be conducted for 3 years from 2000 November to efficiently utilize the CANFLEX fuel technology developed by KAERI and AECL jointly, where the KAERI's works have been conducted under the Korea's national program of the mid- and long-term nuclear R and D programs since 1992. This document is a report to guideline the following activities on the safety assessment for the 24 CANFLEX-NU (CANDU Flexible fuelling-Natural Uranium) fuel bundle demonstration irradiation at Wolsong-1 Generating Station: 'bundle manufacture and QA', 'Fuel handling aspects such as loading fuel, de-fuelling and segregation, and visual in-bay examinations', 'Flasking and shipping', 'Post-irradiation examination', and 'Follow-up documentation to be produced'

[en] Flat space is not stable in massive gravity, in the sense that for any nonzero graviton mass m, no matter how small it may be, any nontrivial solution for the massive field equations is not asymptotically flat as one goes far away from the source, i.e., r→ This is because, although one may be able to construct a locally stable solution with respect to flat space, it does not approach flat space in the limit r→ This is still true even if one takes a successive set of both limits r→ and m→0. Flat space in massive gravity as well as in its massless limit is only an isolated trivial solution. This leads to the conclusion that Einstein's general relativity is an isolated theory