bluuebunny/crossref_metadata_2025_split huggingface dataset:
Calculations of the Dual Functional Lithium Lead-Test Blanket Module for ITER With Three-Dimensional Deterministic Method
Authors: Zhang GuangChun , Wu Hongchun , Cao Liangzhi , Zheng Youqi 
Published: October 2013

Neutronics calculations and analysis of ITER test blanket module lay the foundation for the design, construct and experiment of ITER. In this paper, the realistic 3D neutronics calculations of the dual functional lithium lead-test blanket module (DFII-TBM) have been carried out by means of the 3D MOC code and the SPN code, which are both deterministic methods and developed by NECP lab, adopting the multi-group nuclear data library FENDI/MG-2.1. The main features of the TBM nuclear response are assessed, paying a particular attention to the neutron flux and tritium production rate.
The 3DMOC code is a coupling a 3D method of characteristics (MOC) to the common geometry module. It could calculate the flux throughout three-dimensional systems by the MOC, which has been proved a very flexible and effective method for the neutron transport calculation in a complex geometry. In this code, a modular ray tracing technique is adopted to reduce the amount of the ray tracing data and the Coarse Mesh Finite Difference (CMFD) acceleration method is employed to save computing time, which could well solve the difficulties when applying MOC in three-dimensional geometries.
The SPN code is another three-dimensional Boltzmann transport equation calculation code. The simplified PN method is used to treat the directional variable, and the Nodal method treats the spatial variable. Consequently, this code has an advantage in shorting computing time when applied to big geometry problems.
Considering the big geometry of DFII-TBM and the large number of the cross sections of nuclear data library FENDI/MG-2.1, a two-step approach is adopted. Firstly, the DFII-TBM is dissected into some typical independent parts. 3D calculations are performed on these parts respectively with 3D MOC code and FENDL/MG-2.1 library to obtain the detailed heterogeneous flux distribution. Then the homogenization is carried out to calculate the average homogeneous cross sections, followed by the use of homogeneous cross sections to calculate the flux distribution throughout the DFII-TBM with SPN code.
The results obtained are herewith presented and critically discussed.
Surface Tension of Liquid Sodium With Suspended Nanoparticles
Authors: Ogawa Takuro , Sugiyama Ken-ichiro 
Published: October 2013

Liquid sodium to be described by sodium here after with suspended nanoparticles is expected to mitigate sodium-water reaction, because sodium with suspended nanoparticles will suppress the degree of chemical activity by the atomic interaction between nanoparticles and sodium. In order to investigate this interaction from the view point of physical property, we tried to measure the surface tension of sodium with suspended nanoparticles in a static and dynamic state.
For the measurement of the surface tension in a static state, we employed the pendant drop method. The measurements were done in the globe box keeping inert gas atmosphere, which was required for the experiment using sodium to get rid of an easy chemical reaction of sodium with oxygen and moisture. We succeeded to make pendant drops of sodium and sodium with suspended nanoparticles between 200°C and 500°C.
On the other hand, to evaluate the surface tension in a dynamic state, we employed the method applying the principle of the Kelvin-Helmholtz instability. The measurements were done in the globe box used in the static experiment. Sodium or sodium with suspended nanoparticles throwing a nozzle was ejected into a paraffin pool. Its fragments were made due to the Kelvin-Helmholtz instability. The fragments were retrieved from a paraffin pool and we measured fragment size distribution. We carried out the experiments at temperature of 150°C and 200°C, and the ejection volume rate of 3.0L/min and 6.0L/min.
It was found that droplet sizes of sodium with suspended nanoparticles were increased as compared with those of sodium without nanoparticles. This result physically must have mean that sodium with suspended nanoparticles has larger surface tension than that of sodium without nanoparticles in the present condition. Therefore, we could consider the effect of the atomic interaction might mitigate sodium-water reaction.
IVR Model Study for Passive PWR
Authors: Xu Hong , Zhang Peng , Zhou Zhiwei 
Published: October 2013

1000-MWe scale Pressurized Water Reactor (PWR) is taking service or under construction all over the world, and larger scale plant is studied and developed for its more competitive economics. Not only design basic accidents are analyzed for nuclear safety, the severe accident must also be considered to meet with the increasing requirement of safety. In the “nuclear power plant design safety regulation” (HAF102) issued by Nation Nuclear Safety Administration (NNSA), aim at the preventing and mitigating of severe accident, the regulation bring forward new requirement, which required that during design phase, NPP should consider setting the preventing and mitigation measurement of severe accident as actually as possible. As an approach to prevent the curium from melting down the vessel and entering the containment when a postulated severe accident occurs, In-vessel retention (IVR) of molten core debris via water cooling of the external surface of the reactor vessel has been introduced into AP1000.
External reactor vessel cooling (ERVC) is assumed to be achieved keeping exterior surface of vessel at 400K. It is known to all that different scenario and process results in different IVR molten model. As the core melt, different IVR model is formed at different time, such as two-layer model, three-layer model and four layer model. It is necessary to study the IVR model when severe accident process moves on. This paper studies two-layer and three-layer IVR models and find the features of the models. Based on this, sensitivity study of important parameters has also been analyzed. It is useful for us to understand the mechanism of the molten pool. This paper has some directive significance on future IVR strategy research and also provides theoretical support to safety evaluation of PWR plants.
Role of Complicated Flow Fields in Lower Plenum on Coolant Flow Distribution to Core of ABWR
Authors: Watanabe Shun , Abe Yutaka , Kaneko Akiko , Watanabe Fumitoshi , Hirao Kazuki 
Published: October 2013

In order to achieve increase of power outputs of an ABWR, it is extremely important to evaluate coolant flow in a lower plenum. Numerical simulation is helpful to predict the coolant flow, and thus verification experiments are needed. Hence, the present study is focusing on the construction of benchmark of CFD code. The objective of the study is to clarify relation between flow distribution to the core and the complicated flow structures in the lower plenum.
We constructed a 1/10 model of a lower plenum to conduct flow experiment for validation of CFD analysis. In the experiment, it turned out that coolant flow distribution becomes to be uniform at core support beam, and there are complicated flows like vortices around side entry orifices. Regarding differential pressure distribution, it was revealed that profile of the region including side entry orifices is very dominant. This pressure loss might be caused by contraction flow at the orifices. Such flow structures were also described by CFD analysis. As good performance of analysis, we investigated flow distribution to the core particularly by using CFD results. And relation between the flow distribution and the complicated flow structures were also discussed.
Integration of Direct/Indirect Influences of Severe Accidents for Improvements of Nuclear Safety
Authors: Silva Kampanart , Ishiwatari Yuki , Takahara Shogo 
Published: October 2013

Risk evaluation is an important assessment tool of nuclear safety, and a common index of direct/indirect influences of severe accidents as a compound of risk is necessary then. In this research, various influences of severe accidents are converted to monetary value and integrated. The integrated influence is calculated in a unit of “cost per severe accident” and “cost per kWh”. The authors must emphasize that the aim is not to estimate the accident cost itself but to extend the scope of “risk-informed decision making” for continuous safety improvements of nuclear energy.
To calculate the “cost per severe accident” and the “cost per kWh”, typical sequences of severe accidents are picked-up first. Containment failure frequency (CFF) and source terms of each sequence are taken from the results of level 2 probabilistic risk assessment (PRA). The source terms of each sequence is input into the level 3 PRA code OSCAAR which was developed by Japan Atomic Energy Agency (JAEA). The calculations have been made for 248 meteorological sequences, and the results presented in this study are given as expectation values for various meteorological conditions. Using these outputs, the cost per severe accident is calculated. It consists of various costs and other influences converted into monetary values.
This methodology is applied to a virtual 1,100 MWe BWR-5 plant. Seismic events are considered as the initiating events. The data obtained from the open documents on the Fukushima Accident are utilized as much as possible. Sensitivity analyses are carried out to identify the dominant influences, sensitive assumptions/parameters to the cost per accident or per kWh. Based on these findings, optimization of radiation protection countermeasures is recommended. Also, the effects of sever accident management are investigated.
Mechanical Aspects of the Canadian Generation IV Supercritical Water-Cooled Pressure Tube Reactor
Authors: Yetisir M. , Gaudet M. , Martin D. 
Published: October 2013

Canada is developing a next generation (Gen IV) reactor, the Canadian Super-Critical Water-cooled Reactor (SCWR), which has the potential of meeting all design goals of the Gen IV International Forum (GIF). These design goals include enhanced safety features (inherent safe operation and deploying passive safety features), improved economic and resource utilization (∼40% more efficient than current nuclear power generating stations, sustainable fuel cycle (will burn thorium, which is three times more abundant than uranium), enhanced sustainability, and greater proliferation resistance compared to the current fleets (i.e., Gen III and Gen III+) of reactors. The Canadian SCWR concept is a pressure-tube type reactor that uses supercritical water as a coolant, a separate low-pressure heavy water moderator, a high efficiency fuel channel that includes a zirconium alloy pressure and a ceramic zirconia insulator, and a direct steam power cycle.
This paper presents the evolution of the Canadian SCWR core design, simplifications introduced in the design to deal with design challenges, and ongoing design activities.
Estimation of Thyroid Doses From Land Contamination Maps for the Fukushima Disaster
Authors: Saji Genn 
Published: October 2013

Starting with sketchy information acquired during the still on-going Fukushima Daiichi disaster, the thyroid doses were estimated, based on the detailed and precise Cs-137 land contamination density maps constructed through a joint effort of MEXT and US DOE/NNEA. The basic methodology has already been benchmarked in the assessment of the radiological consequences of the Chernobyl accident [1].
From the release fraction assessment based on the contamination maps as well as on-site meteorological data obtained and reported by TEPCO’s temporary monitoring cars, the heavy land contamination zone stretching to a NW direction was found induced with the hydrogen explosion which occurred in 1F1 at 15:36 of March 12, only one day after the tsunami. Due to this early iodine release, the shorter half-lived I-133 induced an additional 20% more thyroid doses from I-131 through inhalation.
The results, as presented in Table 7 and Figure 3, predicted rather large thyroid doses, comparable but less than the author’ previous estimation of thyroid doses through inhalation pathway among the public living near the Chernobyl NPP during the disaster. However, age specific doses are more widely spreading among children aged less than 15 years old and not distinctively large among babies, thanks to early restriction of fresh milk.
It should be noted that, above Zone V (300K-1000K/m2 in Cs-137), the estimated thyroid doses with a range of several tens of mGy are already of concern in a possible future outbreak of hypothyroidism. However, if the exposed individuals happened to be staying indoors at the time of plume passage, an order of magnitude of reduction is expected, although the alleviating effects depends on the airtightness of buildings.
Even with these uncertainties, the estimated thyroid dose calls for continued health monitoring of those young residents who happened to be staying in these highly contaminated zones at the time of the plume passage.
Pool Boiling and Flow Boiling CHF Enhancement at Atmospheric Pressure Using Magnetic Nanofluid
Authors: Lee Taeseung , Lee Jong Hyuk , Jeong Yong Hoon 
Published: October 2013

In this study, we suggest a new working fluid: magnetic nanofluid, or magnetite-water nanofluid, which is a colloidal suspension of magnetite nanoparticles in the pure water. By using the nanofluid, we can expect the critical heat flux (CHF) enhancement, and also for the magnetic nanofluid. Since the magnetite nanoparticles can be controlled by an external magnetic field, the magnetic nanofluid is regarded as a controllable nanofluid, and thus, we can expect the advantages of magnetic nanofluid: 1) the nanoparticle suspension in nanofluid can be maintained by applying the alternating magnetic field, 2) the nanofluid concentration can be localized by applying the magnetic field for a region of interest and 3) the magnetite nanoparticles can be removed from magnetic nanofluid easily.
In this study, we focused on the CHF characteristics of magnetic nanofluid in both pool boiling and flow boiling. The first part is for the pool boiling CHF of magnetic nanofluid. At atmospheric pressure, saturated pool boiling CHF experiments were conducted using Ni-Cr wire for magnetic nanofluid and the other nanofluids. Among the various nanofluids, magnetic nanofluid has the highest value of pool boiling CHF, and the enhancement ratio (with respect to the pure water) ranges from 170 to 240 percent. To elucidate the mechanism underlying the pool boiling CHF enhancement, three approaches were introduced: 1) scanning electron microscope (SEM) images were obtained to explain the pool boiling CHF enhancement mechanism due to the deposited nanoparticles, which is related to the surface wettability of the heat transfer surface, 2) ultra-high speed movie were taken and analyzed to observe the bubble dynamics at the heat transfer surface and 3) the strength of electricity-induced magnetic field neat the heat transfer surface were calculated to examine the effect of magnetic field on the pool boiling CHF.
The second part is for the flow boiling CHF of magnetic nanofluid. A series of flow boiling CHF experiments were performed at atmospheric pressure and low mass flux conditions. Based on the experimental data, we conclude that the use of magnetic nanofluid improves the flow boiling CHF characteristics: the flow boiling CHF enhanced for the magnetic nanofluid. This is mainly due to the deposition of magnetite nanoparticles on the heat transfer surface, which results in the improvement of wettability and re-wetting characteristics. And we need enough time to ensure the nanoparticle deposition and the flow boiling CHF enhancement, when a nanofluid is used as a working fluid.
Antibody Response to Achromobacter xylosoxidans during HIV Infection Is Associated with Lower CD4 Levels and Increased Lymphocyte Activation
Authors: Tatro Erick T. , Purnajo Intan , Richman Douglas D. , Smith Davey M. , Gianella Sara 
Published: October 2013

ABSTRACTInflammation during HIV infection is associated with worse disease outcomes and progression. Many mechanisms have been indicted, including HIV itself, coinfections, and gut microbial translocation. Concerning microbial translocation, we hypothesized that adaptive immune responses to a specific bacterial species known to be present in gut-associated lymphoid tissue are higher among HIV-infected individuals than among HIV-uninfected controls and are associated with T cell activation and lower CD4 T cell counts. By characterizing the IgG response toAchromobacter xylosoxidans, we found that HIV-infected participants who were immunoresponsive (n= 48) had significantly lower CD4 percentages (P= 0.01), greater CD4 activation (percentages of RA−CD38+) (P= 0.03), and higher soluble CD14 (P= 0.01). HIV-positive individuals had higher anti-A. xylosoxidansIgG titers than HIV-uninfected individuals (P= 0.04). The results suggest an abnormal adaptive immune activation to gut microflora during HIV infection.
Safety and Immunogenicity of Single-Dose Live Oral Cholera Vaccine Strain CVD 103-HgR, Prepared from New Master and Working Cell Banks
Authors: Chen Wilbur H. , Greenberg Richard N. , Pasetti Marcela F. , Livio Sofie , Lock Michael , Gurwith Marc , Levine Myron M. 
Published: October 2013

ABSTRACTCurrently, no cholera vaccine is available for persons traveling from the United States to areas of high cholera transmission and who for reasons of occupation or host factors are at increased risk for development of the disease. A single-dose oral cholera vaccine with a rapid onset of protection would be particularly useful for such travelers and might also be an adjunct control measure for cholera outbreaks. The attenuatedVibrio choleraeO1 vaccine strain CVD 103-HgR harbors a 94% deletion of the cholera toxin A subunit gene (ctxA) and has a mercury resistance gene inserted in the gene encoding hemolysin A. We undertook a phase I randomized placebo-controlled two-site trial to assess the safety and immunogenicity of a preliminary formulation of CVD 103-HgR prepared from new master and working cell banks. Healthy young adults were randomized (5:1 vaccinees to placebo recipients) to receive a single oral dose of ∼4.4 × 108CFU of vaccine or a placebo. Blood serum vibriocidal and cholera toxin-specific IgG antibodies were measured before and 10, 14, and 28 days following vaccination or placebo. Excretion of the vaccine strain in the stool was assessed during the first week postvaccination. A total of 66 subjects were enrolled, comprising 55 vaccinees and 11 placebo recipients. The vaccine was well tolerated. The overall vibriocidal and anti-cholera toxin seroconversion rates were 89% and 57%, respectively. CVD 103-HgR is undergoing renewed manufacture for licensure in the United States under the auspices of PaxVax. Our data mimic those from previous commercial formulations that elicited vibriocidal antibody seroconversion (a correlate of protection) in ∼90% of vaccinees. (This study has been registered at ClinicalTrials.gov under registration no. NCT01585181.)
Blood Collection Tubes Influence Serum Ficolin-1 and Ficolin-2 Levels
Authors: Brady Allison M. , Spencer Brady L. , Falsey Ann R. , Nahm Moon H. 
Published: October 2013

ABSTRACTThe ficolins are members of a recently discovered family of host innate opsonins that can activate the lectin pathway of complement. The ficolins bind many ligands, although they are typically described as binding acetylated sugars. Ficolin-1 (M-ficolin) and ficolin-2 (L-ficolin) are known to bindStreptococcus pneumoniaeserotypes 19C and 11A, respectively. While studying the binding of ficolins to pneumococci, we found variations in ficolin-2 binding among serum samples collected in different types of blood collection tubes. Plastic tubes, which contain a silica clot activator, yielded sera with reduced ficolin-2 binding and apparent ficolin-2 levels. We found that the silica clot activator eluted from plastic red-top tubes inhibited ficolin-2 ligand binding, while other related proteins, like mannose-binding lectin (MBL) and ficolin-1, were not affected. These tube types did not affect the concentrations of other related opsonins (C1q, MBL, or ficolin-3 [H-ficolin]). Interestingly, we also found that ficolin-1 levels were increased 2- to 3-fold in plastic serum separator tubes compared to the increases in other tube types. These findings have implications for future ficolin-1 and ficolin-2 studies, as proper sample collection and handling are essential.
Proposal of a Consensus Set of Hypervariable Mycobacterial Interspersed Repetitive-Unit–Variable-Number Tandem-Repeat Loci for Subtyping of Mycobacterium tuberculosis Beijing Isolates
Authors: Allix-Béguec Caroline , Wahl Céline , Hanekom Madeleine , Nikolayevskyy Vladyslav , Drobniewski Francis , Maeda Shinji , Campos-Herrero Isolina , Mokrousov Igor , Niemann Stefan , Kontsevaya Irina , Rastogi Nalin , Samper Sofia , Sng Li-Hwei , Warren Robin M. , Supply Philip 
Published: October 2013

ABSTRACT

Mycobacterium tuberculosis
Beijing strains represent targets of special importance for molecular surveillance of tuberculosis (TB), especially because they are associated with spread of multidrug resistance in some world regions. Standard 24-locus mycobacterial interspersed repetitive-unit–variable-number tandem-repeat (MIRU-VNTR) typing lacks resolution power for accurately discriminating closely related clones that often compose Beijing strain populations. Therefore, we evaluated a set of 7 additional, hypervariable MIRU-VNTR loci for better resolution and tracing of such strains, using a collection of 535 Beijing isolates from six world regions where these strains are known to be prevalent. The typeability and interlaboratory reproducibility of these hypervariable loci were lower than those of the 24 standard loci. Three loci (2163a, 3155, and 3336) were excluded because of their redundant variability and/or more frequent noninterpretable results compared to the 4 other markers. The use of the remaining 4-locus set (1982, 3232, 3820, and 4120) increased the number of types by 52% (from 223 to 340) and reduced the clustering rate from 58.3 to 36.6%, when combined with the use of the standard 24-locus set. Known major clonal complexes/24-locus-based clusters were all subdivided, although the degree of subdivision varied depending on the complex. Only five single-locus variations were detected among the hypervariable loci of an additional panel of 92 isolates, representing 15 years of clonal spread of a single Beijing strain in a geographically restricted setting. On this calibrated basis, we propose this 4-locus set as a consensus for subtyping Beijing clonal complexes and clusters, after standard typing.