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A sodium-cooled fast reactor has been designed to attain a high burn-up core in commercialized fast reactor cycle systems. The sodium-cooled fast reactor adopts a wire spacer between fuel pins. The wire spacer performs functions of securing the coolant channel and mixing between subchannels. In high burn-up fuel subassemblies, the fuel pin deformation due to swelling and thermal bowing may decrease the local flow velocity in the subassembly and influence the heat removal capability. Therefore, understanding the flow field in a wire-wrapped pin bundle is important. This study performed particle image velocimetry (PIV) measurements using a wire-wrapped three-pin bundle water model to grasp the flow field in the subchannel under conditions, including the laminar to turbulent regions. The PIV results confirmed that the normalized flow velocity near the wrapping wire in the low Re number condition was relatively decreased compared to that in the high Re number condition. Meanwhile, in the region away from the wrapping wire, the maximum flow velocity was increased by decreasing the Re number. Accordingly, the PIV measurements using the three-pin bundle geometry without the wrapping wire were also conducted to understand the effect of the wrapping wires on the flow field in the subchannel. The results confirmed that the mixing due to the wrapping wire occurred, even in the laminar condition. These experimental results are useful not only for understanding the pin bundle thermal hydraulics, but also for the code validation.

Six commercially available movable core guide wires were compared with each other and with a new design in glass models simulating tortuous vessels. The results demonstrate a wide variability in performance of the commercially available wires and the superiority of the new design.

The local susceptibility profile is here proved to be a reliable source of unique information about the internal domain structure and the local magnetization process. In the present work, the profile is studied for a series of magnetically soft amorphous wires having different magnetostriction constants and exhibiting various domain structures. The presence of closure domain structures near the ends of the wires is confirmed. These domains appear regardless of the value of the magnetostriction constant. They reduce the stray field energy and strongly enhance the local values of susceptibility. Index Terms - Amorphous wires, domain structure, magnetic susceptibility, magnetization process.

An experimental and analytical study was conducted to determine the feasibility of using grit-impregnated, epoxy-coated, prestressing strands (coated strands) and smooth surfaced, epoxy-coated, deformed, welded-wire-fabric in thin prestressed concrete (PC) subdeck panels and to determine the transfer lengths for 9.53-mm (3/8 in.) diameter, seven-wire, 1,860-MPa (270 ksi), low-relaxation, coated and bare (uncoated) strands. When coated strands are located at the middepth of a PC panel, the experimental testing revealed that a 76-mm (3 in.) minimum thickness was required to prevent concrete cracking when the strands were cut, that the amount of concrete side cover affected the uncoated-strand transfer lengths, and that a 152-mm (6 in.) strand spacing did not appear to affect the transfer lengths for either the coated or uncoated strands. The experimental and analytical investigations showed that the measured coated-strand transfer lengths were about one-half of those measured lengths for uncoated strands and that the American Concrete Institute (ACI) Building Code expression for strand transfer length overestimates the coated-strand transfer lengths and underestimates the uncoated-strand transfer lengths.

This paper reports an experimental program conducted to measure the transfer lengths (or transmission lengths) of pretensioned seven-wire strands in pretensioned concrete specimens. The primary goals of the research were to investigate the ability of the larger 15.2 mm (0.6 in.) strand to reliably transfer its pre-stressing forces within a reasonable transfer length, and to evaluate the current design provisions for transfer lengths. Eight specimens were pretensioned with 12.7 mm (0.5 in.) diameter strands and 10 specimens were pretensioned with 15.2 mm (0.6 in.) strands. Experimental results indicate that the larger 15.2 mm (0.6 in.) diameter strands require longer transfer lengths and cause more distress than the smaller 12.7 mm (0.5 in.) strands. However, the tests indicate that 15.2 mm (0.6 in.) strands can be readily employed for pretensioned concrete structures. Additionally, the results demonstrate that current design practice estimating transfer lengths can lead to unsafe designs and that a more reliable expression for transfer lengths should be adopted.

We have developed a new method of measuring minimum quench energy (MQE) of superconducting wire. There have been conventional methods using heating wires, whose diameters are [approximately]0.1mm and are glued by epoxy resin. When we induce a pulse heat to superconducting wires, a duration of the pulse must be several hundreds micro seconds to demonstrate actual disturbances (for instance wire motion) in a superconducting magnet. In spite of this fact, thermal diffusion time constants of the conventional heaters are larger than the duration of the actual disturbance, because of these electrical insulator of the heating wire and the epoxy bind. Therefore, this kind of heater is not able to demonstrate the actual disturbance. To solve this problem, We have proposed a new constitution of a heater. In our method, heat generation is introduced in high resistive layer on a surface of a superconducting wire. The high resistive layer is consist of carbon paste. The thickness of the carbon paste layer is [approximately]20[[micro]meter], thus a time constant of this heater is expected to be small enough to demonstrate the actual disturbance. Adopting our new method to our MQE measurement, we successfully evaluate MQE of superconducting wires with high precision. Several results are introduced in this paper.

The mechanical properties of multifilamentary [Nb.sup.3]Sn wires have an important role in their application in large scale magnetic systems. The influence of heat treatment schedules and design factors on the mechanical properties of rectangular and round section bronze route wires was investigated. Ultimate tensile strength, yield strength and elongation of stabilized and non-stabilized wires 0.4 mm x 4 mm in section and 0.8 -1.5 mm in dia containing 4000 - 14000 Nb filaments before and after heat treatment were studied. It was shown that a change of the wire design, volume fraction of copper, heat treatment regimes influence strongly on strength and plasticity of wires. The level of the mechanical properties of stabilized wires depends on the volume fraction and location of stabilizer in the section of [Nb.sub.3]Sn wire.

The results of investigation on the influence of the intermediate heat treatment on the mechanical and electrical properties of Cu-Nb alloy microcomposites are presented. The transformation of structure and mechanical properties at the different stages of the production process are discussed. Different designs of microcomposites are developed which allowed to vary the combination of mechanical strength and electroconductivity in sufficiently wide range: UTS - from 900 to 1,200 MPa and conductivity from 65 to 75% IACS. Developed approach to manufacturing process are valid for production of the conductors with enhanced (above 10 mm x 10 mm) cross sections.

A magnetization process of FeCoSiB amorphous wire under the ac circumferential magnetic field with a triangular waveform is investigated. We obtained the locus chart of the magnetization vector under circular magnetic field, [h.sub.[Theta]]. By increasing the time differential component of [h.sub.[Theta]], d[h.sub.[Theta]]/dt, the hysteresis becomes noticeable gradually. It is believed that an eddy current damping is responsible for this phenomenon.

The mechanism of particle capture and retention of strongly magnetic particles in HGMS is investigated both theoretically and experimentally. Good quantitative agreement between the theory and experiments is found.

A magnetic sensor which consists of a compound magnetic wire and search coil has a novel performance to induce the detection voltage independent of changing rate of AC external field frequency in every one cycle. The detection voltage is changed by the previous magnetized state of the compound magnetic wire. This paper reports the effect of a DC bias magnetic field which is applied with an AC magnetic field to make an asymmetric field. To make a compound wire a previous magnetized state, the demagnetized wire is magnetized by various orienting DC field [H.sub.0]. When a symmetric AC field Hex and DC bias field Hb are applied to the wire, the wire is magnetized by an asymmetric magnetic field, which consists of a reset field Hr = Hex + Hb and a set field Hs = Hex - Hb. According to the relationship among the critical field Hp, [H.sub.0] and Hb, Hp is independent of the previous magnetized state of wire at Hb of 25 Oe or larger, and the pulse voltage is always induced at a fixed Hp. This phenomenon is very stable and reproducible.

In this paper we report some results on the dependence of the pulsed voltage output on the applied torsion or tensile stress in [Fe.sub.77.5][Si.sub.77.5][B.sub.15] amorphous wires used as magnetostrictive delay lines. The obtained results show a not monotonic dependence of the response of the delay line on applied torsion. For applied tensile stress the response could be fitted by a linear curve for as-cast wires and by an exponential curve for annealed wires. The good ratio between minimum and maximum magnetostrictive delay line signals and the absence of hysteresis suggest the possibility to use this technique in load cells and torque sensors.

Dependence of magnetization dynamics and magneto-impedance effect in positively magnetostrictive [Fe.sub.77.5][Si.sub.7.5][B.sub.15] amorphous wires on annealing conditions was studied. The observed MI ratio of the annealed samples was as much as 36% and the optimum annealing conditions were suggested. The locus of magnetization vector of the annealed wire indicated that the circumferential magnetization was easily proceeded in the annealed wire. It was also suggested that the effect of oxidation should be considered for the samples annealed in air.

The dependence of the magnetic properties of amorphous wire on the diameter have been investigated. The anisotropy constant, hence the internal stress, of the wire increases with the wire diameter. The size of the pinned reverse domain at the wire end increases with the wire diameter. Domain observation shows that irrespective of the change in the wire diameter, the domain structure basically consists of chevron domain layer sandwiched between the surface maze domain and the inner core domain.

Results on the magnetic behavior and properties of negative and nearly zero magnetostrictive amorphous glass-covered magnetic wires and on their changes determined by glass removal, applied tensile stresses, and annealing are reported. The experimental data allow the explanation of their specific magnetic behavior as emerging from the changes produced in the domain structure by these factors. The similarity in behavior between negative and nearly zero magnetostrictive glass-covered wires is due to the very high values of internal stresses induced during preparation.

Results on the helical magnetic anisotropy in positive magnetostrictive amorphous glass-covered magnetic wires are presented. Measurements of the circumferential magnetization component in [Fe.sub.77.5][Si.sub.7.5][B.sub.15] amorphous glass-covered wires show the existence of a non diagonal anisotropy component that determines an inclination of the easy axis of magnetization in the inner region of as-cast wires. Applied torque leads to an increase of the azimuthal magnetization and contributes to the increase of the easy axis inclination, determining an increase of the switching field at which the axial magnetization reversal occurs in these wires. The torsion sensitivity of wires after glass removal is higher than that of glass-covered wires.

We have investigated the giant magnetoimpedance (GMI) effect in fibers of different soft magnetic materials and in Permalloy wires. The fibers have been tested in the radio frequency (rf) range, by measuring the voltage drops in different parts of the circuit. The wires have been tested in the ultra high frequency (uhf) range, by measuring the transmission coefficient [s.sub.21] of coaxial lines having as central conductor a HyMu80 wire. The two methods provided quite similar results showing a strong GMI effect for very different magnetic samples.

The anisotropy distribution in [Fe.sub.77.5][Si.sub.7.5][B.sub.15] amorphous glass-covered wires and wires after glass removal is investigated by FMR measurements. The peaks of the FMR spectra allow the determination of easy axes and anisotropy fields. The anisotropy distribution changes with glass removal and applied stress. The results are explained by considering the magnetoelastic anisotropy of amorphous wires. Index terms--amorphous glass-covered wires, ferromagnetic resonance, magnetic anisotropy, magnetoelastic interactions.