Bundle experiments

A polishing cloth residue is bundled into a cube of 1 m on the half-side dimension. It is stored in an environment of 35 °C and the convective heat transfer is very good between the air and the bundle. Experiments show that the cloth residue has the following properties ... 

One of the interesting measurements among the bundle experiments was done by Rakitin et al. [71]. They compared the conductivity of a A-DNA bundle to that of an M-DNA [71-74] bundle (DNA that contains an additional metal ion in each base pair, developed by the group of Jeremy Lee from Saskatchewan). The actual measurement was performed over a physical gap between two metal electrodes in vacuum (see Fig. 10). Metallic-like behavior was observed for the M-DNA bundle over 15 /um, while for the A-DNA bundle a gap of -0.5 V in the I-V curve was observed followed by a rise of the current. 

Boldyrev, A.V, Palagin, A.V., Shestak, V.E., Steinbriick, M and Stuckert, J. (2005), Modelling of B4C oxidation by steam at high temperature based on separate-effects tests and its application to the bundle experiment QUENCH-07. Sdentific report, Forschungszentrum Karlsruhe, Wissenschaftliche Berichte FZKA 7118. 

Prediction of heat transfer in SCW can be based on data from fossil-fired power plants, as discussed by Pioro and Duffey (2007). Computational tools for more complex geometries like fuel assemblies are available, but stUl need to be validated with bundle experiments. System codes for transient safety analyses have been upgraded to include SCW, including depressurization transients to subcritical conditions. Flow stability in the core has been studied numerically. As in BWRs, flow stability can be ensured using suitable inlet orifices in fuel assembhes. 

A large-scale CFD calculation is useful for the design of the Super FR and Super LWR. For example, the ACE-3D code for supercritical water calculation was developed for analysis of the 37-fuel rod bundle geometry. Validation of the code with 7-rod bundle experiments can be expected to reduce future R D work on fuel assembhes. The flow characterization within the RPV will also be made by CFD calculation. 

These equations apply to single tubes or to flat surfaces in a large pool. In tube bundles the equations are only approximate, and designers must rely upon experiment. Palen and Small [Hydrocarbon Process., 43(ll), 199 (1964)] have shown the effect of tube-bundle... 

We will discuss below the reeent experimental observations relative to the eleetrieal resistivity and magnetoresistance of individual and bundles of MWCNTs. It is interesting to note however that the ideal transport experiment, i.e., a measurement on a well eharacterised SWCNT at the atomic scale, though this is nowadays within reaeh. Nonetheless, with time the measurements performed tended gradually eloser to these ideal eonditions. Indeed, in order to interpret quantitatively the eleetronie properties of CNTs, one must eombine theoretieal studies with the synthesis of well defined samples, which structural parameters have been precisely determined, and direet electrical measurements on the same sample. 

Burn-out data and descriptive details of 24 different rod-bundle geometries, representing all known published work up to 1965, have been compiled and analyzed by Macbeth (M4). Data that have subsequently appeared are given by Matzner (M10), Janssen (J2), Edwards and Obertelli (El), Becker et al. (B11), Moeck (M14), and Hesson (H3). All these data refer to water, and in most of the bundles the direction of water flow is vertically upwards, parallel to the heated rods however, a few tests have also been made with the bundles horizontal, also using parallel flow. Nearly all the experiments have been performed at around 1000 psia, so that the correlation of rod-bundle data must be restricted to this pressure alone. 

All the references to burn-out have thus far been concerned with uniformly heated channels, apart from some of the rod bundles where the heat flux varies from one rod to another, but which respond to analysis in terms of the average heat flux. In a nuclear-reactor situation, however, the heat flux varies along the length of a channel, and to find what effect this may have, some burn-out experiments on round tubes and annuli have been done using, for example, symmetrical or skewed-cosine axial heat-flux profiles. Tests with axial non-uniform heating in a rod bundle have not yet been reported. 

After a few minutes irradiation with a high pressure mercury lamp at about 50 C, a rather complete cover of grafted acrylic acid, acrylamide and other vinyl monomers could be obtained. In later experiments a continuous grafting method has been developed where a tape or a fiber bundle after suitable pretreatment is grafted by UV irradiation for a few seconds. Homopolymer formed is removed by washing and grafted polymer analyzed by dye absorption, IR reflection and ESCA spectroscopy. 

Rod bundle heat transfer analysis (Anklam, 1981a) A 64-rod bundle was used with an axially and radially uniform power profile. Bundle dimensions are typical of a 17 X 17 fuel assembly in a PWR. Experiments were carried out in a steady-state mode with the inlet flow equal to the steaming rate. Generally, about 20-30% of the heated bundle was uncovered. Data were taken during periods of time when the two-phase mixture level was stationary and with parameters in the following ranges ... 

Effects of nuclear heating. Both out-of-pile loop experiments and in-pile reactor operating measurements are available. The rod bundle data obtained in an operating reactor (Farmer and Gilby, 1971) agree with those obtained in an out-of-pile loop, as shown in Figure 5.63. 

The uncertainty in the predicted CHF of rod bundles depends on the combined performance of the subchannel code and the CHF correlation. Their sensitivities to various physical parameters or models, such as void fraction, turbulent mixing, etc., are complementary to each other. Therefore, in a comparison of the accuracy of the predictions from various rod bundle CHF correlations, they should be calculated by using their respective, accompanied computer codes.The word accompanied here means the particular code used in developing the particular CHF correlation of the rod bundle. To determine the individual uncertainties of the code or the correlation, both the subchannel code and the CHF correlation should be validated separately by experiments. For example, the subchannel code THINC II was validated in rod bundles (Weismanet al., 1968), while the W-3 CHF correlation was validated in round tubes (Tong, 1967a). 

Waters, E. D., 1963, Fluid Mixing Experiments with a Wire-Wrapper 7-Rod Bundle Fuel Assembly, Rep. HW-70178 Rev., Hanford Lab., General Electric Co., Hanford, WA. (App.)... 

Here, the components of hCT molecules observed by the DDMAS and CPMAS experiments are defined as A and B forms, respectively. For early stages, it is proposed163 that a formation of micelles corresponding to the a-helical bundle is reversibly formed from the monomers with the same aggregation number n0 (An0),... 

---