bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison and Harmonization of French RCCM and ASME Code
Authors: Faidy Claude
Published: April 2011

The objectives of this paper is to discuss technical harmonization of Nuclear Codes and Standards, based on French long experience in Codes and Standards used for design-fabrication and operation of nuclear components (mainly pressure retaining components). After a long period of use of ASME Section III code, during the Westinghouse licensing process, AFCEN (AREVA, EDF and the major manufacturers) decided to develop their own AFCEN French Codes. The 1st version has been issued in 1980 and the last one in 2007, completed by annual addendum. During more than 20 years the 2 Codes, RCCM and ASME Section III, have leave separately, with different constraints like industrial history, localisation of fabrication, more new plants in France than in USA, different R&D programs to support Code improvement… Recently a detailed review of differences for class 1 vessel has showed under a “general global quality equivalence”, a lot of differences in the Code development process, in the Code organization, in the scopes, in the State of the Art fulfillment, in ageing consideration at the design stage, in relation with national or international regulations, in term of standards used or complementary specification needs… The harmonization of Codes and Standards is possible under an important effort to move toward new ideas, more international rules and with a strong support of national safety authorities.
Design of a Multijunction Antenna Unit for EAST Lower Hybrid Current Drive
Authors: Jia Hua , Liu Fukun , Li Jun , Wang Mao
Published: April 2011

A multijunction antenna unit has been designed and will be used to fabricate the new 4.6GHz Lower Hybrid Current Drive (LHCD) launcher for the long pulse operation of the Experimental Advanced Superconducting Tokamak (EAST). In this paper, the construction and design method of the multijunction antenna unit are described, and then the reflection coefficients of the unit with the matched load and with the plasma load are analyzed and discussed respectively by using High Frequency Structure Simulator (HFSS) code and by using numerical calculation based on linear coupling theory. The simulation result shows that the return loss of the antenna unit keeps below −25dB in a bandwidth of 100MHz and the power is distributed equally in the secondary waveguides of the unit. Numerical calculation result also shows that the unit has good coupling property in a wide range of tokamak plasma parameters.
Development of Electrical Resistivity Measurement Systems for Inspecting Void Swelling in Irradiated Microscopy Discs
Authors: Sagisaka Mitsuyuki , Isobe Yoshihiro , Garner Frank , Fujita Satoshi , Okita Taira
Published: April 2011

Results are presented of resistivity change measurements made on a model Fe-Cr-Ni-Ti-C austenitic alloy irradiated in the Fast Flux Test Facility to doses ranging from 1.87 to 67.8 dpa. Two different electrical resistivity measurement systems were developed to overcome problems associated with examination of small microscopy specimens in order to investigate small changes in resistivity arising from voids and other radiation-induced microstructural features. A correlation is shown between resistivity changes arising primarily from void swelling. However, contributions arising probably from radiation-induced redistribution and perhaps precipitation of carbon and titanium can dominate the resistivity at low dpa levels.
Development of Personal Dosimeter Based on New Measurement Method
Authors: Wang Min , Fang Fang , Duan Xiaojuan , Zhao Xiang
Published: April 2011

In this article, the defect of measurement method using pulse-counting for total measurement is discussed. Time-to-count measurement principle is introduced and Monte Carlo method was successfully used to simulation. The author designs a personal dosimeter with that principle, which eliminates the influence of dead time and other factors and improves the performance of the entire instrument.
Design Study on Power Flattening to Sodium Cooled Large-Scale CANDLE Burning Reactor With Using Thorium Fuel
Authors: Okawa Tsuyoshi , Nakayama Sinsuke , Sekimoto Hiroshi
Published: April 2011

The CANDLE (Constant Axial shape of Neutron flux, nuclide densities and power shape During Life of Energy production) burnup strategy is a new burnup concept. The CANDLE reactors generate energy by using only natural or depleted uranium as make up fuel and achieve about 40% burnup without fuel recycling of the conventional nuclear energy concept. So far the CANDLE cores feature a relatively large peak-to-average power density and discharge burnup distribution. Peaked power and burnup distribution are undesirable as they deteriorate economical performance. The objective of this paper is to study the feasibility of power flattening of sodium cooled large scale CANDLE reactor toward commercial use by using thorium fuel loading into the inner core zone. When power density profile becomes flat, it is expected that the axial position of burning region is aligned at the same height for each radial position. It makes core height shorter and raises the average power density farther. The shorter core has usually more merits such as smaller loss of coolant pressure obtained during passing fuel channel and more negative coolant void coefficient. For this purpose, thorium is added uniformly to the uranium fuel in the inner core. If we choose the amount of thorium proper, net radial current of neutrons in the inner core becomes zero in the inner core, and at the boundary between inner and outer core enough neutrons leak from the uranium region and the net radial current is still zero at this point. In the outer region the neutrons leak outward. By this way, we can make the power density distribution flat in the inner core. In the present work, the power density profile is intended flatten for the metallic fuel CANDLE reactors by adding thorium uniformly in the inner core region. The maximum axially integrated power density (radial peaking factor) decreases from 1.87 with only uranium fuel to 1.44 with uranium and thorium fuels. We can expect increasing average discharge burnup and decreasing fuel inventory and pressure drop.
Construction of Westinghouse AP1000™ Nuclear Power Plants in China
Authors: Harrop Grenville , Poirier Bill P.
Published: April 2011

In July 2007, China entered a new era of sustainable, safe, and ecologically sound energy development by committing to build four AP1000™ units to be constructed in pairs at the coastal sites of Sanmen (Zhejiang Province) and Haiyang (Shandong Province). Both sites have the planned ability to accommodate at least six AP1000 units. The Westinghouse AP1000 is the only Generation III+ reactor to receive design certification from the U.S. Nuclear Regulatory Commission (NRC). With a design that is based on the proven performance of Westinghouse-designed pressurized water reactors (PWRs), the AP1000 is an advanced 1100 megawatt (MW) plant that uses the forces of nature and simplicity of design to enhance plant safety and operations. Excavation commenced for the first of four China AP1000 units in February 2008, and placement of the basemat concrete for Sanmen Unit 1 was completed on schedule in March 2009. This was soon followed by the placement of the first major structural module; the auxiliary building. As part of localization and the Peoples Republic of China (PRC) desire for self-reliance, a China-based module factory is constructing the major modules and manufacturing the containment vessel plates. The fabrication and welding of the containment vessel bottom head for Sanmen Unit 1 is now complete. The 2010 milestones for Sanmen Unit 1 include the setting of major modules such as the reactor vessel cavity, the steam generator, and refueling canal modules, plus containment vessel rings 1, 2, 3, and 4. All major equipment orders have been placed and the first deliveries are beginning to arrive. The technology transfer is also well underway. The Haiyang Unit 1 basemat was placed on schedule in September 2009 and Sanmen Unit 2 Nuclear Island (NI) concrete basemat placement was completed a month earlier than the milestone date of January 2010. Sanmen Unit 1 will be fully operational in November 2013 followed by Haiyang Unit 1 in May 2014. Operational dates for Sanmen Unit 2 and Haiyang Unit 2 are September 2014 and March 2015, respectively. As one of the world’s largest consumers of energy, China’s path in achieving sustainable energy has profound global economic and environmental consequences. The contract with the Westinghouse and Shaw Consortium for four AP1000 units is the largest of its type between the People’s Republic of China and the United States.
Bubble Size and Group Influence for CFD Simulation in Vertical Tube Upward Flow
Authors: Li Songwei , Zhang Hong
Published: April 2011

The near-wall bubble congregating in vertical tube upward flow exerts an influence on fluid heat transfer. A 0.5m test section is simulated using CFX10.0 to research the bubble influence on the heat transfer. The vapor-water two-phase CFD calculation is done. The bubbles are added at near wall area, taking no account of the mass transfer between water and vapor. The different bubble max diameter and the different MUSIG model size group get different calculation results, these results are compared, include the distribution of vapor void fraction, the wall temperature distribution and near-wall water temperature distribution, the bubble mean diameter. A guide setting is advised. The calculation result shows that the max bubble diameter and the MUSIG size group on the vapor void fraction distribution is large. The near-wall void fraction gets down to the least (nearly zero, while at the inlet, near wall vapor fraction is 0.95) at 0.1m∼0.14m axis height, then rises. The wall temperature gets highest at the same height, and then appears a flat, keeping this temperature about 0.1m long, after that the temperature gets down, then rises along the axis.
Prediction Model for Bubble Contact Circle Diameter on Heating Wall
Authors: Chen De-qi , Pan Liang-ming
Published: April 2011

Phenomenal and theoretical analysis about the evolution of bubble contact circle diameter during bubble growing is presented in current paper; and it is found that bubble contact diameter is dependent on bubble growth rate and bubble radius strongly. By analyzing experimental data from open literature, the relation between dimensionless bubble contact diameter, kw, and dimensionless bubble growth time, t+, is obtained; based on this, a model relative to dimensionless bubble growth rate, dR+/dt+, and dimensionless bubble radius, R+, is proposed for prediction of bubble contact diameter. With proper values for coefficients, aw and nw, this model can well predict experimental data of bubble circle contact diameter in published literatures, with an error within ±20%.
Residual Life Prediction of Corroded Pipeline Based on Electrochemical Model
Authors: Wang Wen-he , Yi Jun , Ma Ai-xia , Shen Shi-ming , Yu Xiao-chun
Published: April 2011

According to the corrosion failure characteristics of buried oil and gas pipelines, electrochemical corrosion rates of the local corrosion and pitting corrosion flaws were derived by Faraday’s laws, and the limit size model of corrosion defects was established based upon ASME-B31G criteria. A new method of the residual life prediction for buried pipelines was finally developed based on the corrosion rate model and limit size model of corrosion defects, and the prediction method was validated with an example and the results showed that the method is reliable for pipelines with corroded defects.
Effect of Hazardous Impurities on Steam Generator Tube Degradation
Authors: Lu Yucheng
Published: April 2011

Steam generator (SG) tubing materials are susceptible to corrosion degradation in certain electrochemical corrosion potential (ECP) regions under aggressive local chemistry conditions developed under deposits or in SG crevices. Because of the hideout of impurities, the areas under sludge and inside SG crevices may be very aggressive and contain high concentrations of chlorides and other impurities. These areas are the locations where SG tubing materials are susceptible to the major forms of degradation such as pitting, crevice corrosion, intergranular attack (IGA) and stress corrosion cracking (SCC). The corrosion susceptibility of each SG alloy is different and is a function of ECP and chemical environment. Electrochemical corrosion behaviors of major SG tube alloys were studied under plausible aggressive crevice chemistry conditions. The potential hazardous conditions leading to SG tube degradation and the conditions, which can minimize SG tube degradation, have been determined and documented in a form of safe ECP/pH zones for SG operation. SCC tests and accelerated corrosion tests were carried out to verify and revise the safe ECP/pH zones. This information has been incorporated and updated into a system health monitor tool, ChemAND®, which was developed by AECL for utilities to monitor online the status of the SG alloys and prevent material degradation surprises through appropriate SG water chemistry management. Recently, further studies were performed to investigate the effect of several aggressive SG impurities on the boundary conditions that will lead to the degradation of SG alloys. These aggressive species include chloride, different sulphur species, lead, copper, magnesium, and calcium. This paper presents the effect of chloride concentration and copper contamination on Alloy 800 SG tubing corrosion degradation at 300°C under SG crevice chemistry conditions. The data provide important information to support SG materials degradation and life management.
Study the TOF Detector in RIBLL With GEANT4
Authors: Li Jiaxing , Zhang Denggao , Liu Pingping
Published: April 2011

We present here an ellipsoidal timing detector in Radioactive Ion Beam Line in Lanzhou (RIBLL). The photons induced by radioactive beam ions passing through a thin plastic-scintillator foil BC422, emit from the foil center corresponding to one focal point of an aluminum ellipsoidal mirror and are reflected to another focus point at which the cathode of a photomultiplier tube locates. A time resolution of about 115ps is achieved for 12N and the counting rate up to 108 pps is allowed. The simulation was carried out using GEANT4 Monte Carlo toolkit. The photons total collection efficiency following projectile from different position, photon collection efficiency and time resolution of photon to photocathode of 3 different cases were calculated. Also the main factors influencing the detector’s time resolution and some proposals are given.
Stored Energy Scale and Evaluation in Nuclear Plant Test Facility
Authors: Chen Lian , Ding Ming
Published: April 2011

The stored energy in the component in a nuclear power plant test facility would gradually release to coolant. This would affect the coolant temperature and thermal-hydraulic behavior of the testing. This paper analytically investigated the relationship between stored energy and scaling ratio, design pressure of the pressure vessel when modeling an ideal power plant test facility. Taking AP1000 as an example, the stored energy ratio between the test vessel and prototype reactor vessel was calculated. Comparisons manifest that in order to meet the stored energy scaling criteria, the height ratio, diameter ratio should be deliberately selected. Further investigation revealed that the stored energy increasing with design pressure can be compensated by changing vessel material. The research indicated several practical principals for coping with the stored energy in test facility design.
Development of a Software for Calculation of Kinetic Parameters of PWR Reactors
Authors: Jahanbin Ali , Boroushaki Mehrdad
Published: April 2011

In this research, new software package for neutronic calculations, especially kinetic parameters of PWR reactors, has been developed. The program used to link the WIMS-D5, BORGES and CITVAP nuclear codes has been written in Visual C# programming language. This software was used for calculation of kinetic parameters of WER-1000 and NOK Beznau reactors. The ratios (βeff)i/(βeff)core of parameters, which are an important input data for the reactivity accident analysis, were also calculated. The results were compared with final safety analysis report (FSAR) and published documents.
Thermal-Hydraulic Experiments Under High Pressure Condition
Authors: Liu Wei , Hidesada Tamai , Takase Kazuyuki , Hayafune Hiroki , Futagami Satoshi , Kisohara Naoyuki
Published: April 2011

For steam generator with straight double-walled heat transfer tube that used in sodium cooled Faster Breeder Reactor, flow instability is one of the most important items need researching. As the first step of the research, thermal hydraulics experiments with water were performed under high pressure condition in JAEA with using a circular tube. Pressure drop, heat transfer coefficients and void fraction data were derived. This paper summarizes the pressure drop characteristics under 15MPa. Several two-phase flow multiplier models were checked and Chisholm model and homogeneous model were found being the best ones for the prediction of present data. A sudden pressure drop decreasing tendency was observed when flow pattern shifts from bubbly/churn flow to annular flow. The reason for this decrease is tried interpreted.
Application of Extra High Purity Austenitic Stainless Steel to Weld Overlay
Authors: Ioka Ikuo , Suzuki Jun , Kiuchi Kiyoshi , Nakayama Jumpei
Published: April 2011

Stress Corrosion Cracking (SCC) was understood to be the result of a combination of susceptible material, a corrosive environment and tensile stress above a threshold. An Extra High Purity Fe-Cr-Ni austenitic stainless steel (EHP alloy) was developed with conducting the new multiple refined melting technique in order to suppress the total impurities (C, O, N, P, S, B, Si, Mn) less than 100ppm. EHP alloy has great intergranular corrosion resistance. It is considered that intergranular corrosion becomes initiation of SCC. So, we try to apply EHP alloy to weld overlay materials to prevent from occurring SCC. EHP alloy (Fe-25Cr-20Ni, Fe-25Cr-35Ni) was melted by the new technique. The conventional weld metals (Type Y316L and Inconel 82) were also prepared as comparisons. Specimens were machined from the welded metal of each material. Intergranular corrosion tests were performed in boiling 8kmol/m3 HNO3 solutions containing 1kg/m3 Cr(VI) ions. The intergranular corrosion of conventional weld metals was severer than those of EHP alloys. Crevice Beam Bending tests to evaluate susceptibility of SCC were carried out in high temperature water of 561K with saturated oxygen (32ppm) for 1000h. Though cracks and intergranular corrosion were observed in all specimens, cracks of conventional weld metals were much more than those of EHP alloys. It was confirmed that EHP alloy has also excellent SCC resistance as a weld overlay material.
High Temperature Aging and Corrosion Study on Alloy 617 and Alloy 230
Authors: Mo Kun , Lovicu Gianfranco , Tung Hsiao-Ming , Chen Xiang , Stubbins James F.
Published: April 2011

The very high temperature gas-cooled reactor (VHTR), with dual capacities of highly efficient electricity generation and thermochemical production of hydrogen, is considered as one of the most promising Gen-IV nuclear systems. The primary candidate materials for construction of the intermediate heat exchanger (IHX) for the VHTR are Alloy 617 and Alloy 230. To have a better understanding of the degradation process during high temperature long-term service and provide practical data for engineering design of the IHX, aging experiments were performed on Alloy 617 and Alloy 230 at 900 and 1000°C. Mechanical properties (hardness and tensile strength) and microstructure were analyzed on post-aging samples after different aging periods (up to 3000 h). Both alloys attained increased hardness during the early stages of aging, and dramatically soften after extended aging times. Microstructural analysis including Transmission Electron Microscopy (TEM), Scanning Electron Microscope (SEM), Energy Dispersive X-ray spectroscopy (EDS), and Electron Backscatter Diffraction (EBSD) were carried out to investigate the microstmcture evolution during aging. A carbide particle precipitation, growth and maturing process was observed for both alloys, which corresponds to the changes of materials’ mechanical properties. Few changes in grain boundary character distribution (GBCD) and grain size distribution were observed after aging. In addition, high temperature corrosion studies were performed at 900 and 1000°C for both alloys. Alloy 230 exhibits much better corrosion resistance at elevated temperature compared to Alloy 617.
Modelling Rewetting of Heated Surfaces as Intermittently Bursting Liquid-Metal Contacts
Authors: Ilyas Muhammad , Walker Simon P. , Hewitt Geoffrey F.
Published: April 2011

Understanding of the rewetting behavior of heated vertical fuels pins is an important part of establishing reliable cooling of a PWR core following a loss of coolant accident (LOCA). Ahead of the quench front, complex and chaotic processes occur over a very small axial range, where high temperature gradients exist. In particular, repeated cyclic wetting and explosive evaporation at frequencies in the range 0.1 to 1.0 kHz is observed experimentally [1]. Despite extensive experimental and theoretical studies, the heat transfer mechanism in this region is still not well understood. In this paper we propose a mechanism, based on these observations, to explain the cyclical behavior. This postulated mechanism is transient near-surface cooling, followed by temperature recovery, of the metal substrate, with explosive vaporization when the homogeneous nucleation temperature is restored at the metal-water interface. A one-dimensional model of this cyclical process is constructed. The model indicates that the mechanism is plausible, predicting the observed periodic behavior, with predicted frequencies consistent with those observed in experiments.
State of the Art NDT Mechanized Equipment Used in PWR Reactor Vessel Inspection
Authors: Li Ming , Chen Huaidong , Xiao Xuezhu , Lv Tianming , Yu Zhe
Published: April 2011

The equipment used to carry out Non Destructive Testing (NDT) examination have played a significant role, as they have rapidly evolved to fulfill the requirements of the industry as well as to adapt to new materials and manufacturing technologies. To a great extent, the development of the robotics in the last 30 years has made this evolution possible, contributing to optimize the critical component inspection time in terms of quality and productivity. The safety operation and significance of reactor vessel is obvious to the nuclear power station. The application of NDT mechanized equipment is a key factor to enhance the safety, reliability and availability of the reactor vessel for a cost and time effective operation. According to requirement from code and the authority concerning detailed ultrasonic inspection requirement, Reactor Pressure Vessel (RPV) need to performance full scope examination for different position during PSI and ISI period. At the same time, consider RPV component have high radiation, RPV inspection machined usually was in operation wholly submerged in primary water, the machine is composed of different function parts, mechanical and control system, ultrasonic data acquisition and evaluation system and television testing system. This paper introduces how to choose and define some basic ultrasonic parameters, for example: choose probe frequency, define probe angle and for different depth use different focus probe to cover full sound path between 6dB focus lengths. Finally, preset a simple brief about typical function of ultrasonic data acquisition system and evaluation system.
Reactor Protection Diversity Requirements and the Typical Solution Base on DCS
Authors: Huang Wei-Jun , Tian Ya-Jie , Dong Xiao-Sheng , Zhang Li Ming , Liu Guang-Ming , Jiang Guo-Jin
Published: April 2011

According to the study of series of related standards, the defense-in-depth and diversity have become the basic requirements for digital I&C and should be strictly followed when carrying out the overall scheme design of Digital Control System, in which the risk of Common Cause Failure has to be prevented or coped with. This paper analyzes the requirements according to the diversity principle and illustrates the typical solution of the diversified protection base on the CPR1000 NPP. Some concepts will be helpful to the design of DCS.
Steam Generator Ageing Management Database
Authors: Chen Junqi , Xue Fei , Liu Peng , Zhou Lin , Lin Lei , Ti Wenxin
Published: April 2011

Steam generator (SG) is one of the key important equipments to safety of nuclear power plant (NPP), which is covered by NPP ageing management program (AMP). SG tube rapture often takes place due to stress corrosion crack for a long time according to international application. And its reliability is the only one vital weakness of nuclear steam supply system (NSSS), so it is necessary to increase its reliability for safety operation in ageing management (AM) area. Utility engineers and managers frequently use information of their individual SG to optimize SG AM in their plants. However the SG AM data has not always been readily available, thus the Steam Generator Ageing Management Database (SGAMDB) was developed to integrate decentralized information and provide a valuable data center that the data needed could be easily and quickly retrieved, and can serve as the basis platform for optimizing SG ageing evaluation and management. SGAMDB is an online interactive integrated information management system. Some modern information technologies are applied, especially real-time data acquisition and virtual reality technology. The in-situ application of SGAMDB can improve efficiency in SG AM. As the main platform for SG AM, it not only contains all equipment condition information and important operation data that are needed based on data warehouse technology, but also provides fundamental online monitoring, trend analysis, ageing assessment functions and basis data management functions. The assessment models and technology of real-time online monitoring can ensure SG a controllable state during in-service time, find the change of operation environment and adjust the operation condition early, so as to reduce influence for equipment ageing.
The Development of SRCM and the Application at Home and Abroad
Authors: Yang Lifei , Hong Jiang
Published: April 2011

It is well-known that RCM is an advanced and effective maintenance strategy in practice. With the development of the automation and mechanization in modern industry, RCM method turns to be complex and consumes more resources in real production. However, the development and application of the Streamline RCM (SRCM) has injected new vitality for the new situation, especially in the nuclear power plants. This paper firstly introduces the background, the characteristics of the SRCM and the differences from RCM, and then shows the process in detail as well as the application status of the SRCM in country and abroad. It is proved that SRCM is a unique available method which saves the time and resource consumed, ensuring the integrity and correctness of the classical RCM. Finally, the weak points and the prospect are reviewed and prospected.
Development of Advanced Loop-Type Fast Reactor in Japan: Progress of Design Study Based on Preliminary Assessment Results
Authors: Sakamoto Yoshihiko , Kotake Shoji , Aoto Kazumi , Toda Mikio
Published: April 2011

The Japan sodium-cooled fast reactor (JSFR) is an advanced loop-type reactor concept which is investigated in the Fast Reactor Cycle Technology Development project in Japan. This paper describes some important progress on the JSFR design study and R&D discussed in a preliminary assessment for the first milestone of this project. As for the reactor system design, structural integrity against both thermal stress and seismic force was investigated. Then, the specification of the reactor vessel was established. Also, investigation of design options to extend a design margin against seismic force has been suggested. Regarding thermal hydraulics issues in the reactor vessel, design measures against cover gas entrainment and vortex cavitations have been introduced to the reactor system design based on R&D results. Further investigation is in progress for design optimization or improvement of preventive effect. The hot-leg piping design of primary cooling circuit was also established taking “Type-IV” damage into account.
Calibration of Activation Counter by a 2.48 kJ Plasma Focus Device
Authors: Rajabi Moghadam Sahar , Davani Fereydoon Abbasi , Shirani Bidabadi Babak
Published: April 2011

A silver activation counter has been constructed by plastic scintillator plates along with silver foils for determination the neutron yield of a 2.48kJ plasma focus device, SBUPF1. This counter was calibrated by source removal method with an Am-Be 5 Ci neutron source which was placed above the anode of plasma focus device. Deuterium gas up to 8mbar pressure was injected to this device, and the neutron yield produced by pulsed D-D fusion of plasma focus device was measured by the counter. the neutron yield of SBUPF1 in 8mbar pressure was obtained 3.71±0.32×107 neutrons per shot. This result has relatively agreed with the neutron yield measured by silver activation Geiger counters.
A Procedure to Address the Fuel Rod Failures During LB-LOCA Transient in Atucha-2 NPP
Authors: Adorni Martina , Del Nevo Alessandro , D’Auria Francesco , Mazzantini Oscar
Published: April 2011

Depending on the specific event scenario and on the purpose of the analysis, it might be required the availability of calculation methods that are not implemented in the standard system thermal hydraulic codes. This may imply the use of a dedicated fuel rod thermo-mechanical computer code. This paper provides an outline of the methodology for the analysis of the 2A LB-LOCA accident in Atucha-2 NPP and describes the procedure adopted for the use of the fuel rod thermo-mechanical code. The methodology implies the application of best estimate thermal-hydraulic, neutron physics and fuel pin performance computer codes, with the objective to verify the compliance with the specific acceptance criteria. The fuel pin performance code is applied with the main objective to evaluate the extent of cladding failures during the transient. The procedure consists of a deterministic calculation by the fuel performance code of each individual fuel rod during its lifetime and in the subsequent LB-LOCA transient calculations. The boundary and initial conditions (e.g. pin power axial profiles) are provided by core physics and three dimensional neutron kinetic coupled thermal-hydraulic system codes (RELAP5-3D©) calculations. The procedure is completed by the sensitivity calculations and the application of the probabilistic method, with the aim of a better understanding of the uncertainties involved and their technological consequences on the behavior of the fuel rods, not addressed in the current paper.
Post Test Analysis of LB LOCA Transient in PSB-VVER by CATHARE2 Code
Authors: Coscarelli Eugenio , Del Nevo Alessandro , D’Auria Francesco
Published: April 2011

The OECD/NEA PSB-VVER project provided unique and useful experimental data from the large-scale PSB-VVER test facility for code validation. This facility represents the scaled down layout of the Russian designed PWR reactors, namely VVER-1000. The fifth experiment is a LB LOCA in cold leg. The objectives of the test are the investigation of the thermal-hydraulic response of the VVER-1000 following a LB LOCA accident as well as the investigation of the phenomena involved in the transient by the availability of experimental data which are useful for the validation of thermal-hydraulic system codes. The paper discusses the achievements of the assessment of CATHARE2 code from the qualitative and the quantitative evaluations of the results. The results are compared with the analysis carried out by RELAP5-3D code. The quantification of the accuracy is based on the Fast Fourier Transform Base Method, developed at University of Pisa, which provides an integral representation of the accuracy quantification in the frequency domain.
The Advanced Installation Method of Containment Liner Plates
Authors: Kim Woosung , Park Jihong
Published: April 2011

In Korea, newly advanced installation method of containment liner plates was developed and adopted for the construction of Shin Wolsong Unit 2 NPP. The key method of the new installation method of concrete liner plates was using a three-stage-based modularization (lifting of 3 plate ring module) instead of using conventional installation method. In this paper, overall newly developed installation method of containment liner plates including such as characteristics, merits and procedures were described briefly.
Effect of Irradiation Deformation and Graphite Varieties on the Irradiation Equivalent Stress and Life of Nuclear Graphite
Authors: Fang Xiang , Wang Haitao , Yu Suyuan
Published: April 2011

Graphite is selected as moderator, reflector and major internal structural material in high temperature gas-cooled reactors (HTRs) because of its unique characteristics. Inside the core, both high temperature and fast neutron irradiation can influence the mechanical property, thermal property, dimensional change and some other characteristics of graphite in evidence, while the creep of graphite plays an important role in the whole process. There have been several kinds of creep models, and the creep process is divided into two parts in most of models: primary creep and secondary creep. The primary is always treated as exponential function while the secondary is linear. A code based on user subroutines of MSC.MARC is developed in INET in order to perform three-dimensional finite element analysis of irradiation behavior of the graphite components for the HTRs. In this paper, the irradiation behavior of nuclear graphite was simulated, and the impact of irradiation-induced deformation of various kinds of graphite on the irradiation-induced stresses and lives is discussed. In order to describe the creep behavior, the linear elastic model is chosen while the influence of high temperature and irradiation to the dimensional change, physical parameters and creep property of nuclear graphite is used as original data.
Ultraviolet photodetectors based on MgZnO thin films
Authors: Wu Cheng-Zhi , Ji Liang-Wen , Liu Chien-Hung , Peng Shi-Ming , Young Sheng-Joue , Lam Kin-Tak , Huang Chien-Jung
Published: April 2011

In this work, Ti/Au Ohmic contacts to both Mg0.24Zn0.76O and ZnO film-based metal-semiconductor-metal (MSM) photodetectors (PDs) were fabricated on glass substrates for comparative analysis. The transmittance spectra measured around the optical energy gap revealed that Mg0.24Zn0.76O films have a larger optical energy gap (3.54 eV) than ZnO films (3.25 eV). Mg0.24Zn0.76O MSM-structured ultraviolet (UV) PDs show a much higher UV-to-visible rejection ratio of 2.78×103 than those made of ZnO films. This can be attributed to the low dark current (0.08 pA) of the Mg0.24Zn0.76O UV PDs and the small full width at half maximum (0.34°) of the Mg0.24Zn0.76O (002) x-ray diffraction peak, indicating better crystal quality than that of ZnO. With an applied bias of 5 V and illuminations at 350 and 380 nm, the Mg0.24Zn0.76O and ZnO film-based MSM PDs exhibited responsivities of 0.4 and 0.32 A/W, respectively.
Angiotensin II Type 2 Receptor Signaling Attenuates Aortic Aneurysm in Mice Through ERK Antagonism
Authors: Habashi Jennifer P. , Doyle Jefferson J. , Holm Tammy M. , Aziz Hamza , Schoenhoff Florian , Bedja Djahida , Chen YiChun , Modiri Alexandra N. , Judge Daniel P. , Dietz Harry C.
Published: April 2011

Transforming growth factor–β promotes aortic aneurysm formation through activation of its “noncanonical” signaling pathway.
Teleportation of Nonclassical Wave Packets of Light
Authors: Lee Noriyuki , Benichi Hugo , Takeno Yuishi , Takeda Shuntaro , Webb James , Huntington Elanor , Furusawa Akira
Published: April 2011

Teleportation is demonstrated with bunches of photons.
Deterministic Preparation of a Tunable Few-Fermion System
Authors: Serwane F. , Zürn G. , Lompe T. , Ottenstein T. B. , Wenz A. N. , Jochim S.
Published: April 2011

Optical traps are used to prepare up to 10 cold lithium atoms to be used for simulating few-body fermionic systems.
58 Ways of Looking at a Blackberry
A History of Communications
Media and Society from the Evolution of Speech to the Internet

by Marshall T. Poe

Cambridge University Press, Cambridge, 2011. 349 pp. $85. ISBN 9781107004351. Paper, $24.99. ISBN 9780521179447.
Authors: Kelty Christopher
Published: April 2011

Surveying the origins and impacts of different forms of communication, Poe provides a fresh approach to understanding the history of media.
Another Spin on Graphene
Authors: Castro Neto Antonio H.
Published: April 2011

Electrical measurements on graphene reveal further exotic electronic properties of this one-atom-thick material.
Make It Quantum and Continuous
Authors: Grangier Philippe
Published: April 2011

Robust teleportation of a fragile Schrödinger's-cat state was achieved with nonclassical wave-like states of light.
Fukushima Radiation Creates Unique Test of Marine Life's Hardiness
Authors: Reardon Sara
Published: April 2011

Monitoring seafood and fish taken from the waters around the leaking Fukushima Daiichi plant makes sense, according to radiation geochemists, but they warn against overreacting to the perceived risk of ocean contamination.
Tennessee House Bill Opens Door to Challenges to Evolution, Climate Change
Authors: Mervis Jeffrey
Published: April 2011

U.S. science educators are wringing their hands over what they characterize as a significant legislative victory for those who oppose the teaching of evolution.
Uncertain Future for Tropical Ecology
Authors: Simons Craig
Published: April 2011

Three premier research outfits are scaling back ambitions—and struggling to maintain local staffs as funds grow scarce.
A Badly Battered Vesta Awaits Dawn's Arrival
Authors: Kerr Richard A.
Published: April 2011

A group of impact modelers argued at the Lunar and Planetary Science Conference that the object that crashed into asteroid Vesta—the asteroid belt's second-most-massive body—and reshaped its geology was eight times as massive as previously thought.
Impact of Hepatitis B Virus (HBV) X Gene Mutations on Hepatocellular Carcinoma Development in Chronic HBV Infection
Authors: Lee Jong-Han , Han Kwang-Hyub , Lee Jae Myun , Park Jeon Han , Kim Hyon-Suk
Published: April 2011

The hepatitis B virus (HBV) PreS mutations C1653T, T1753V, and A1762T/G1764A were reported as a strong risk factor of hepatocellular carcinoma (HCC) in a meta-analysis. HBV core promoter overlaps partially with HBx coding sequence, so the nucleotide 1762 and 1764 mutations induce HBV X protein (HBx) 130 and 131 substitutions. We sought to elucidate the impact of HBx mutations on HCC development. Chronically HBV-infected patients were enrolled in this study: 42 chronic hepatitis B (CHB) patients, 23 liver cirrhosis (LC) patients, and 31 HCC patients. Direct sequencing showed HBx131, HBx130, HBx5, HBx94, and HBx38 amino acid mutations were common in HCC patients. Of various mutations, HBx130+HBx131 (double) mutations and HBx5+HBx130+HBx131 (triple) mutations were significantly high in HCC patients. Double and triple mutations increased the risk for HCC by 3.75-fold (95% confidence interval [CI] = 1.101 to 12.768,P= 0.033) and 5.34-fold (95% CI = 1.65 to 17.309,P= 0.005), respectively, when HCC patients were compared to CHB patients. Functionally, there were significantly higher levels of NF-κB activity in cells with the HBx5 mutant and with the double mutants than that of wild-type cells and the triple-mutant cells. The triple mutation did not increase NF-κB activity. Other regulatory pathways seem to exist for NF-κB activation. In conclusion, a specific HBx mutation may contribute to HCC development by activating NF-κB activity. The HBx5 mutation in genotype C2 HBV appears to be a risk factor for the development of HCC and may be used to predict the clinical outcomes of patients with chronic HBV infection.
Improving the Yield of Blood Cultures from Patients with Early Lyme Disease
Authors: Liveris Dionysios , Schwartz Ira , Bittker Susan , Cooper Denise , Iyer Radha , Cox Mary E. , Wormser Gary P.
Published: April 2011

Approximately 45% of untreated United States patients with early Lyme disease associated with erythema migrans have a positive blood culture based on microscopic detection of
Borrelia burgdorferi
in Barbour-Stoenner-Kelly medium after 2 to 12 weeks of incubation. In this study we demonstrate that the yield of blood cultures can be significantly increased to 70.8% by the use of a combined culture-quantitative PCR technique and that among those patients found to have a positive blood culture, positivity was detected in over 90% within just 7 days of incubation. Patients with multiple erythema migrans were almost uniformly culture positive by this technique.
Identification of Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa in Blood Cultures: a Multicenter Performance Evaluation of a Three-Color Peptide Nucleic Acid Fluorescence In Situ Hybridization Assay
Authors: Della-Latta Phyllis , Salimnia Hossein , Painter Theresa , Wu Fann , Procop Gary W. , Wilson Deborah A. , Gillespie Wendy , Mender Alayna , Crystal Benjamin S.
Published: April 2011

A multicenter evaluation was undertaken to evaluate the performance of a new three-color peptide nucleic acid fluorescence
in situ
hybridization assay that identifies isolates directly from blood cultures positive for Gram-negative bacilli (GNB). The assay correctly identified 100% (186/186) of the
Escherichia coli
isolates, 99.1% (109/110) of the
Klebsiella pneumoniae
isolates, and 95.8% (46/48) of the
Pseudomonas aeruginosa
isolates in this study. Negative assay results were correctly obtained for 162 of 165 other GNB (specificity, 98.2%).
Improved Antigen Yield in Pandemic H1N1 (2009) Candidate Vaccine Viruses with Chimeric Hemagglutinin Molecules
Authors: Harvey Ruth , Guilfoyle Kate A. , Roseby Sarah , Robertson James S. , Engelhardt Othmar G.
Published: April 2011

The candidate pandemic H1N1 vaccine virus NIBRG-121 was derived by reverse genetics and comprises the hemagglutinin (HA) and neuraminidase (NA) genes from A/California/7/2009 (CAL) on an A/Puerto Rico/8/34 (PR8) backbone. NIBRG-121 was found to grow poorly in eggs, compared to seasonal H1N1 candidate vaccine viruses. Based on our previous study with H5N1 candidate vaccine viruses, we generated two new viruses with chimeric PR8/CAL HA genes. Here we show that these new viruses have considerably improved growth in eggs and are therefore better candidate vaccine viruses for use in production of pandemic H1N1 (2009) vaccine.
Significant Protection against High-Dose Simian Immunodeficiency Virus Challenge Conferred by a New Prime-Boost Vaccine Regimen
Authors: Schell John B. , Rose Nina F. , Bahl Kapil , Diller Kathryn , Buonocore Linda , Hunter Meredith , Marx Preston A. , Gambhira Ratish , Tang Haili , Montefiori David C. , Johnson Welkin E. , Rose John K.
Published: April 2011

We constructed vaccine vectors based on live recombinant vesicular stomatitis virus (VSV) and a Semliki Forest virus (SFV) replicon (SFVG) that propagates through expression of the VSV glycoprotein (G). These vectors expressing simian immunodeficiency virus (SIV) Gag and Env proteins were used to vaccinate rhesus macaques with a new heterologous prime-boost regimen designed to optimize induction of antibody. Six vaccinated animals and six controls were then given a high-dose mucosal challenge with the diverse SIVsmE660 quasispecies. All control animals became infected and had peak viral RNA loads of 10
6
to 10
8
copies/ml. In contrast, four of the vaccinees showed significant (
P
= 0.03) apparent sterilizing immunity and no detectable viral loads. Subsequent CD8
+
T cell depletion confirmed the absence of SIV infection in these animals. The two other vaccinees had peak viral loads of 7 × 10
5
and 8 × 10
3
copies/ml, levels below those of all of the controls, and showed undetectable virus loads by day 42 postchallenge. The vaccine regimen induced high-titer prechallenge serum neutralizing antibodies (nAbs) to some cloned SIVsmE660 Env proteins, but antibodies able to neutralize the challenge virus swarm were not detected. The cellular immune responses induced by the vaccine were generally weak and did not correlate with protection. Although the immune correlates of protection are not yet clear, the heterologous VSV/SFVG prime-boost is clearly a potent vaccine regimen for inducing virus nAbs and protection against a heterogeneous viral swarm.
Evolution of Drug-Resistant Viral Populations during Interruption of Antiretroviral Therapy
Authors: Wang Dongning , Hicks Charles B. , Goswami Neela D. , Tafoya Emi , Ribeiro Ruy M. , Cai Fangping , Perelson Alan S. , Gao Feng
Published: April 2011

Analysis of a large number of HIV-1 genomes at multiple time points after antiretroviral treatment (ART) interruption allows determination of the evolution of drug-resistant viruses and viral fitnessin vivoin the absence of drug selection pressure. Using a parallel allele-specific sequencing (PASS) assay, potential primary drug-resistant mutations in five individual patients were studied by analyzing over 18,000 viral genomes. A three-phase evolution of drug-resistant viruses was observed after termination of ART. In the first phase, viruses carrying various combinations of multiple-drug-resistant (MDR) mutations predominated with each mutation persisting in relatively stable proportions while the overall number of resistant viruses gradually increased. In the second phase, viruses with linked MDR mutations rapidly became undetectable and single-drug-resistant (SDR) viruses emerged as minority populations while wild-type viruses quickly predominated. In the third phase, low-frequency SDR viruses remained detectable as long as 59 weeks after treatment interruption. Mathematical modeling showed that the loss in relative fitness increased with the number of mutations in each viral genome and that viruses with MDR mutations had lower fitness than viruses with SDR mutations. No single viral genome had seven or more drug resistance mutations, suggesting that such severely mutated viruses were too unfit to be detected or that the resistance gain offered by the seventh mutation did not outweigh its contribution to the overall fitness loss of the virus. These data provide a more comprehensive understanding of evolution and fitness of drug-resistant virusesin vivoand may lead to improved treatment strategies for ART-experienced patients.
Stimulation of Homology-Directed Repair at I-SceI-Induced DNA Breaks during the Permissive Life Cycle of Human Cytomegalovirus
Authors: Kulkarni A. S. , Fortunato E. A.
Published: April 2011

Human cytomegalovirus (HCMV) selectively relocalizes many DNA repair proteins, thereby avoiding a potentially detrimental damage response. In the present study, we evaluated interactions between HCMV and the homology-directed repair (HDR) pathway. In permissive human foreskin fibroblasts, a fluorescence-based double-stranded break repair assay was used to determine that HCMV stimulated HDR. Repair of both stably integrated and extrachromosomal reporter substrates was observed to increase. HDR was also stimulated through individual expression of the viral immediate-early protein IE1-72, mimicking full virus infection. These experiments further demonstrate HCMV's role in modulating critical cellular processes during a permissive infection.