bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of traumatic dental injury on quality of life of Brazilian preschool children and their families
Authors: Viegas Cláudia Marina , Paiva Saul Martins , Carvalho Anita Cruz , Scarpelli Ana Carolina , Ferreira Fernanda Morais , Pordeus Isabela Almeida
Published: February 2014

Aim

The aim of this study was to evaluate the impact of traumatic dental injury (TDI) on the oral health‐related quality of life (OHRQoL) of Brazilian preschool children and their families.

Material and methods

A cross‐sectional study was carried out with 1632 children of both sexes aged 60–71 months in the city of Belo Horizonte, Brazil. Data on OHRQoL were collected using the Brazilian version of the Early Childhood Oral Health Impact Scale (B‐ECOHIS), which was self‐administered by parents/caregivers to record their perceptions regarding the oral health of their children. A questionnaire addressing demographic and socio‐economic data was also sent to parents/caregivers. Oral examinations of the children were performed by a single, previously calibrated dentist (intraexaminer and interexaminer agreement: kappa ≥ 0.83) for the assessment of the prevalence and type of TDI using the diagnostic criteria proposed by Andreasen et al. [2007]. Bivariate and multiple Poisson regression analyses were performed, with the level of significance set at 5%.

Results

The prevalence of negative impact from oral conditions on quality of life was 36.8% and 31.4% for children and families, respectively. TDI was not significantly associated with OHRQoL. Tooth avulsion remained in final multiple models of child OHRQoL [PR = 1.37, 95%CI = 1.02–1.85] and family OHRQoL [PR = 1.55, 95%CI = 1.12–2.14]. Tooth discolouration remained in the final multiple models of family OHRQoL [PR = 1.23, 95%CI = 1.05–1.44].

Conclusions

The presence of TDI in Brazilian preschool children has no impact on quality of life of the children or their families. However, tooth avulsion is associated with a negative impact on OHRQoL in both groups, and tooth discolouration is associated with a negative impact on family OHRQoL.
The Effect of Study Abroad Homestay Placements: Participant Perspectives and Oral Proficiency Gains
Authors: Di Silvio Francesca , Donovan Anne , Malone Margaret E.
Published: February 2014

Although the study abroad homestay context is commonly considered the ideal environment for language learning, host‐student interactions may be limited. The present study explored how language development of students of Spanish, Mandarin, and Russian related to student and host family perspectives on the homestay experience. The study used pretest and posttest Simulated Oral Proficiency Interviews to investigate student oral proficiency gains and surveys to examine beliefs of these students (n = 152) and their hosts (n = 87). Students and families were generally positive about the homestay, with significant variation based on language. A significant relationship was found between students' oral proficiency gains and their being glad to have lived with a host family. Significant correlations were also found between students' language learning satisfaction and their satisfaction with the homestay.
Model collaboration for the improved assessment of biomass supply, demand, and impacts
Authors: Wicke Birka , van der Hilst Floor , Daioglou Vassilis , Banse Martin , Beringer Tim , Gerssen‐Gondelach Sarah , Heijnen Sanne , Karssenberg Derek , Laborde David , Lippe Melvin , van Meijl Hans , Nassar André , Powell Jeff , Prins Anne Gerdien , Rose Steve N. K. , Smeets Edward M. W. , Stehfest Elke , Tyner Wallace E. , Verstegen Judith A. , Valin Hugo , van Vuuren Detlef P. , Yeh Sonia , Faaij André P. C.
Published: February 2014

Existing assessments of biomass supply and demand and their impacts face various types of limitations and uncertainties, partly due to the type of tools and methods applied (e.g., partial representation of sectors, lack of geographical details, and aggregated representation of technologies involved). Improved collaboration between existing modeling approaches may provide new, more comprehensive insights, especially into issues that involve multiple economic sectors, different temporal and spatial scales, or various impact categories. Model collaboration consists of aligning and harmonizing input data and scenarios, model comparison and/or model linkage. Improved collaboration between existing modeling approaches can help assess (i) the causes of differences and similarities in model output, which is important for interpreting the results for policy‐making and (ii) the linkages, feedbacks, and trade‐offs between different systems and impacts (e.g., economic and natural), which is key to a more comprehensive understanding of the impacts of biomass supply and demand. But, full consistency or integration in assumptions, structure, solution algorithms, dynamics and feedbacks can be difficult to achieve. And, if it is done, it frequently implies a trade‐off in terms of resolution (spatial, temporal, and structural) and/or computation. Three key research areas are selected to illustrate how model collaboration can provide additional ways for tackling some of the shortcomings and uncertainties in the assessment of biomass supply and demand and their impacts. These research areas are livestock production, agricultural residues, and greenhouse gas emissions from land‐use change. Describing how model collaboration might look like in these examples, we show how improved model collaboration can strengthen our ability to project biomass supply, demand, and impacts. This in turn can aid in improving the information for policy‐makers and in taking better‐informed decisions.
Understanding diagnostic variability in breast pathology: lessons learned from an expert consensus review panel
Authors: Allison Kimberly H , Reisch Lisa M , Carney Patricia A , Weaver Donald L , Schnitt Stuart J , O'Malley Frances P , Geller Berta M , Elmore Joann G
Published: February 2014

Aims

To gain a better understanding of the reasons for diagnostic variability, with the aim of reducing the phenomenon.

Methods and results

In preparation for a study on the interpretation of breast specimens (B‐PATH), a panel of three experienced breast pathologists reviewed 336 cases to develop consensus reference diagnoses. After independent assessment, cases coded as diagnostically discordant were discussed at consensus meetings. By the use of qualitative data analysis techniques, transcripts of 16 h of consensus meetings for a subset of 201 cases were analysed. Diagnostic variability could be attributed to three overall root causes: (i) pathologist‐related; (ii) diagnostic coding/study methodology‐related; and (iii) specimen‐related. Most pathologist‐related root causes were attributable to professional differences in pathologists' opinions about whether the diagnostic criteria for a specific diagnosis were met, most frequently in cases of atypia. Diagnostic coding/study methodology‐related root causes were primarily miscategorizations of descriptive text diagnoses, which led to the development of a standardized electronic diagnostic form (BPATH‐Dx). Specimen‐related root causes included artefacts, limited diagnostic material, and poor slide quality. After re‐review and discussion, a consensus diagnosis could be assigned in all cases.

Conclusions

Diagnostic variability is related to multiple factors, but consensus conferences, standardized electronic reporting formats and comments on suboptimal specimen quality can be used to reduce diagnostic variability.
Extending and Enhancing the Properties of Porous Cordierite Ceramics by Mo6+ ion Incorporation via Facile Combined Synthesis Technique
Authors: Sanad Moustafa M. S. , Rashad Mohamed M. , Abdel‐Aal El‐Sayed A. , El‐Shahat Mohamed F. , Powers Kevin W.
Published: February 2014

Molybdenum‐doped cordierite ceramics have been fabricated through facile combined techniques, coprecipitation followed by solid state. XRD results revealed that α‐cordierite phase is predominated with increasing Mo6+ ion content. The density measurements showed that the bulk density reduced to the minimum value of 0.61 g/cm3, which corresponds to the maximum porosity of about 76.8% at 5% Mo6+ ion. The dielectric permittivity (ε) of pure cordierite is decreased with increasing Mo6+ ion content. The minimum dielectric loss of Mo‐doped cordierite at 1 MHz was equal 0.008 with 10% Mo6+, while at 1 GHz was equal 0.03 with 5% Mo6+.
Sequencing artifacts in the type A influenza databases and attempts to correct them
Authors: Suarez David L. , Chester Nikki , Hatfield Jason
Published: February 2014

Background

There are over 276 000 influenza gene sequences in public databases, with the quality of the sequences determined by the contributor.

Objective

As part of a high school class project, influenza sequences with possible errors were identified in the public databases based on the size of the gene being longer than expected, with the hypothesis that these sequences would have an error. Students contacted sequence submitters alerting them of the possible sequence issue(s) and requested they the suspect sequence(s) be correct as appropriate.

Methods

Type A influenza viruses were screened, and gene segments longer than the accepted size were identified for further analysis. Attention was placed on sequences with additional nucleotides upstream or downstream of the highly conserved non‐coding ends of the viral segments.

Results and Conclusions

A total of 1081 sequences were identified that met this criterion. Three types of errors were commonly observed: non‐influenza primer sequence wasn't removed from the sequence; PCR product was cloned and plasmid sequence was included in the sequence; and Taq polymerase added an adenine at the end of the PCR product. Internal insertions of nucleotide sequence were also commonly observed, but in many cases it was unclear if the sequence was correct or actually contained an error. A total of 215 sequences, or 22.8% of the suspect sequences, were corrected in the public databases in the first year of the student project. Unfortunately 138 additional sequences with possible errors were added to the databases in the second year. Additional awareness of the need for data integrity of sequences submitted to public databases is needed to fully reap the benefits of these large data sets.
Developing and testing a discharge planning decision support tool for hospitalized pediatric patients
Authors: Holland Diane E. , Conlon Patricia M. , Rohlik Gina M. , Gillard Kris L. , Tomlinson Angie L. , Raadt Dawn M. , Finseth Onalee R. , Rhudy Lori M.
Published: February 2014

Purpose

To develop and test a decision support tool that identifies patients who would benefit from early consult with discharge planners.

Design and Methods

A predictive, correlational design was used with parents/guardians of children (1 month to 18 years; N = 197). Data were collected by interviews and record reviews. Expert consensus determined referral to discharge planning.

Results

Mean age was 8.7 years; mean length of stay was 7.5 days. Forty percent (n = 79) were identified for early referral. The variable “substantial post‐acute care needs” had the strongest association with expert consensus (internally validated AUC = 0.79).

Practice Implications

Findings from this study provide preliminary evidence for a decision support tool to improve the discharge planning process by reducing individual decision‐making variability through systematic matching of patient needs to service delivery.
UNIFIED INTERVAL ESTIMATION FOR RANDOM COEFFICIENT AUTOREGRESSIVE MODELS
Authors: Hill Jonathan , Peng Liang
Published: February 2014

The consistency of the quasi‐maximum likelihood estimator for random coefficient autoregressive models requires that the coefficient be a non‐degenerate random variable. In this article, we propose empirical likelihood methods based on weighted‐score equations to construct a confidence interval for the coefficient. We do not need to distinguish whether the coefficient is random or deterministic and whether the process is stationary or non‐stationary, and we present two classes of equations depending on whether a constant trend is included in the model. A simulation study confirms the good finite‐sample behaviour of our resulting empirical likelihood‐based confidence intervals. We also apply our methods to study US macroeconomic data.
Normal values for solid‐state esophageal high‐resolution manometry in a European population; an overview of all current metrics
Authors: Weijenborg P. W. , Kessing B. F. , Smout A. J. P. M. , Bredenoord A. J.
Published: February 2014

Background

Esophageal high‐resolution manometry (HRM) allows accurate evaluation of esophageal motility. Normal values for HRM were established in the United States and several new parameters were introduced since. We aimed to provide a complete set of normal values for HRM obtained in a European population, including all current metrics used to describe the function of the upper esophageal sphincter (UES), the esophageal body, and the esophagogastric junction (EGJ).

Methods

Fifty healthy volunteers underwent esophageal HRM. Subjects swallowed 10 liquid boluses in supine position, after which UES, EGJ, and contraction wave parameters were evaluated. Mean and median values with 5–95th percentile ranges were calculated.

Key Results

The normative thresholds (5–95th percentile) for the various parameters were; UES resting pressure 34.6–137.7 mmHg, UES residual pressure 0.0–8.5 mmHg, UES 0.2‐s integrated relaxation pressure (IRP) 0.0–14.5 mmHg, EGJ length 3.1–6.3 cm, EGJ resting pressure 3.0–31.2 mmHg, EGJ 4‐s IRP 2.0–15.5 mmHg, intrabolus pressure (IBP) 6.6–19.5 mmHg, distal contractile integral 178–2828 mmHg*s*cm, contractile front velocity (CFV) 2.9–5.9 cm s−1, distal latency 5.4–8.5 s, and transition zone length 0.0–8.2 cm.

Conclusions & Inferences

Most HRM parameters assessed in this study resemble the previously described values on which the current criteria are based, supporting the widespread use of these criteria for clinical purposes. However, vigor of the esophageal contraction was lower and transition zone length larger than in previous reports. Peristaltic breaks occur frequently in healthy subjects.
Dose requirements of remifentanil for intubation in nonparalyzed Chinese children
Authors: Liu Hua‐Cheng , Tao Wei‐Ke , Zeng Rui‐Feng , ShangGuang Wang‐Ning , Li Jun , Huang Wen‐Guang , Dong Zhang‐Lei , Wang Xin , Lian Qing‐Quan
Published: February 2014

Background

The objective of this study was to determine ED50 and ED95 of remifentanil for intubation combined with propofol in nonparalyzed Chinese children.

Methods

Forty‐seven American Society of Anesthesiologists Class I children aged 4–11 years weighing 14–33.5 kg underwent general anesthesia with 2.5 mg·kg−1 of intravenous propofol followed by remifentanil in Wenzhou, China. The initial dose of remifentanil was 2.5 μg·kg−1 injected over 60 s. Intubation was attempted 30 s after the completion of remifentanil injection. Level of difficulty to intubate was graded on a scoring system. If the initial intubation condition was deemed satisfactory, subsequent remifentanil doses were decreased by 0.25 μg·kg−1. If the intubating condition was deemed unsatisfactory, subsequent remifentanil doses were increased by 0.25 μg·kg−1. Mean arterial pressure, heart rate, and pulse oximetry were documented before and after induction, immediately after intubation, and 1 min after intubation.

Results

The ED50 of remifentanil used to render a satisfactory intubating condition used in combination with 2.5 mg·kg−1 of propofol in nonparalyzed Chinese children was 2.30 μg·kg−1 (95% confidence interval: 2.28–2.31 μg·kg−1), and the ED95 is 2.75 μg·kg−1 (95% confidence interval: 2.59–3.35 μg·kg−1). These doses were lower than previously reported.

Conclusion

When used in combination with 2.5 mg·kg−1 of intravenous propofol, ED50 and ED95 of remifentanil for adequate intubation in nonparalyzed children were lower than previously reported, at 2.30 and 2.75 μg·kg−1, respectively.
Do educational outcomes correspond with the requirements of nursing practice: educators' and managers' assessments of novice nurses' professional competence
Authors: Numminen Olivia , Laine Tuija , Isoaho Hannu , Hupli Maija , Leino‐Kilpi Helena , Meretoja Riitta
Published: February 2014

Objective

This study evaluated weather educational outcomes of nurse education meet the requirements of nursing practice by exploring the correspondence between nurse educators' and nurse managers' assessments of novice nurses' professional competence. The purpose was to find competence areas contributing to the acknowledged practice–theory gap.

Design

A cross‐sectional, comparative design using the Nurse Competence Scale was applied.

Subjects

The sample comprised nurse educators (n = 86) and nurse managers (n = 141).

Methods

Descriptive and inferential statistics were used in the data analysis.

Main outcome measures

Educators assessed novice nurses' competence to a significantly higher level than managers in all competence areas (p < 0.001). The biggest correspondence between educators' and mangers' assessments were in competencies related to immediate patient care, commitment to ethical values, maintaining professional skills and nurses' care of the self. The biggest differences were in competencies related to developmental and evaluation tasks, coaching activities, use of evidence‐based knowledge and in activities which required mastering a comprehensive view of care situations. However, differences between educators' and managers' assessments were strongly associated with their age and work experience. Active and improved collaboration should be focused on areas in which the differences between educators' and managers' assessments greatly differ in ensuring novice nurses′ fitness for practice.
On the absence of solar evolution‐driven warming through the Phanerozoic
Authors: Waltham David
Published: February 2014

Reconstructed temperatures through the Phanerozoic indicate a gradual cooling or, at best, no significant temperature trend, despite a 4.4% increase in solar heating. It is possible that an underlying warming trend has simply been swamped by ‘noise’ due to significant data‐errors and/or natural fluctuations. Alternatively, the lack of warming may indicate cooling by biological and/or geological processes, which happen to have the right amplitude to cancel the effects of solar warming. This paper demonstrates that the absence of Phanerozoic warming cannot be explained as a warming trend hidden by noise. It also shows that, given widely accepted estimates of climate sensitivity, it cannot be explained as cancellation by negative feedback in the climate system. The Gaia hypothesis, anthropic selection or some other unconventional mechanism may therefore have to be invoked to explain the absence of long‐term warming through the Phanerozoic.
Reliability Monitor for PWR Safety System Using FMEA and Go-Flow Methodology: Application of Risk Monitor for Nuclear Power Plants
Authors: Hashim Muhammad , Yoshikawa Hidekazu , Matsuoka Takeshi , Yang Ming
Published: February 2014

Author’s proposed risk monitor system of Nuclear Power Plant (NPP) is based on the idea of Plant Defense-in-Depth (DiD) risk monitor and reliability monitor to monitor what degree of safety functions incorporated in the plant system is maintained by multiple barriers of Defense-in-Depth (DiD). In the risk monitor system, the range of risk state is not limited in core damage accident but includes all kinds of dangerous states brought by severe accident. In present study, method of the reliability monitor of a risk monitor system is applied to the PWR safety system in order to evaluate the risk state numerically by pursuing all conditions of reliability evaluation given by plant DiD risk monitor. Large break LOCA is taken as an initiating accident event and the implementation of method of the reliability monitor is discussed in detail for single loop PWR safety system by considering the Multilevel Flow Model (MFM), Failure Mode and Effect Analysis (FMEA), and the qualitative reliability evaluation by Fault Tree Analysis (FTA) and the dynamic reliability evaluation by GO-FLOW. The summary of reliability results of PWR safety subsystems are also presented.
Preliminary Study of the Application of PEFS on PCWA
Authors: Cao Jianhua , Fu Xiangang , Lu Xianghui , Jiang Xiaohua
Published: February 2014

Developing the advanced nuclear power plant design to meet the demanding safety, efficiency and environmental goals of electric utilities requires great efforts. A passive emergency feedwater system (PEFS) combined with other passive engineering safety features (PESF) is introduced into PCWA (Passive Combined With Active) designs. The typical accidents are calculated and analyzed for this safety system design, especially steam generator tube rupture (SGTR). It is preliminarily concluded that this safety system design in PCWA makes a great balance between passive and active safety systems, and no radioactive liquid was released to the environment except some steam from affected steam generator.
Design of Fuzzy-PID Controller for Hydrogen Production Using HTPBR
Authors: Badgujar Kushal Dinkar , Revankar Shripad T.
Published: February 2014

Fuzzy logic offers better control over conventional control method. It has capability of fast execution which is useful to develop real time control system. In this work, a design of Fuzzy-proportional integral derivative (PID) controller to control the power of the high temperature pebble bed reactor (HTPBR) is presented. A simplified reactor model consisting of reactor heat balance and point kinetics model with reactivity feedback due to power coefficient of reactivity and Xenon poisoning is used. The reactor is operated at various power levels by using Fuzzy-PID controller. The Fuzzy logic eliminates the necessity of the tuning the gains of PID controller each time by extending the finite sets of the PID controller gains. Hydrogen production is considered using SI cycle. The process heat required for Hydrogen production using SI cycle is supplied by High Temperature Pebble Bed Reactor. A methodology has been developed for the production of Hydrogen. Simulation results are useful for controlling the reactor power in accordance with hydrogen production rate.
High Temperature Creep Properties of UO2 Fuel Pellets Manufactured by Low Temperature Sintering Technology
Authors: Li Rui , Zhou Yuemin
Published: February 2014

In this paper, the low temperature sintering technology to UO2 pellets has been introduced, and we have studied the high temperature creep properties of the pellets which manufactured by low temperature sintering. The sintering temperatures are 1073K, 1273K, 1473K and 1673K, sintering time are 1 hour, 2 hours and 3 hours respectively. We obtained the highest sintering density of pellets at 1673K with 3 hours, which is 10.41g/cm3 (94.98% theoretical density). The grain size of pellets which prepared by low temperature sintering technology and traditional technology are 9.0μm and 23.8μm respectively. So the high temperature creep properties of the two kinds of pellet must be studied. They were performed at 20–50 MPa, 1673K and 1773K respectively, under a nitrogen atmosphere to shorten the experimental time. According to the results, the creep rates of sintered UO2 with the grain sizes of 9.0μm and 23.8μm under the load of 10MPa are almost the same. The creep process is controlled by both Nabarro-Herring creep and Hamper-Dorn creep for uranium dioxide with grain size of 9.0μm; while Hamper-Dorn creep is the dominant mechanism for uranium dioxide with grain size of 23.8μm.
Flow Characteristics of Fuel Bundle With New Mixing Vane Design
Authors: Yu Wenchi , Pang Zhengzheng , Zhou Yuemin , Li Weicai , Chen Xiaoming
Published: February 2014

The prevalent fuel assembly geometry of Pressurized Water Reactors (PWR) is constituted of open-lattice rod bundles arranged in a square configuration with grid spacers. In order to enhance the coolant mixing effects across the adjacent flow channels, mixing vanes are added to the grid. The presence of the spacer grids with mixing vanes imposes two opposite effects that would affect the thermal-hydraulic characteristics in the core. Grid spacers with optimized mixing vanes will generate more effective swirl flow across the neighboring subchannel to enhance the local heat transfer rate from the fuel rod cladding to the core coolant downstream the grids, however, it would slightly increase the local pressure drop that would render an negative effect, though it is small, on the core thermal margins.

The key elements for mixing effects, such as mixing length, cross and swirl flows, hinged on the coolant flow that is redistributed by the mixing vanes. This paper presents a mixing vane grid design (or concept) that could increase the effectiveness of heat transfer. Its structure includes flow-oriented section and vane. Flow oriented channel section is set on the other side of the neighboring cell which is different from a conventional mixing vane design. For mixing effect, there exists a balance between the incoming flow area and the bending angle. It also effectively draws more coolant from the adjacent cells to the mixing vane. Thus, it is an effective way to create a stable swirl flow downstream. The flow mixing impact travels much longer than that caused by the most conventional mixing vanes.
Development of Electron Beam Welding Technology Using AA6061-T6 Aluminum Alloy for Nuclear Fuel Plate Assembly
Authors: Kim Soo-sung , Lee Don-bae , Lee Yoon-sang , Park Jong-man
Published: February 2014

This study was carried out to establish the electron beam welding process for a nuclear fuel plate assembly fabrication. A preliminary investigation for plate fuel fabrication was conducted with a consideration of weld performance using AA6061-T6 aluminum alloy made by the EBW (Electron Beam Welding) process. The optimum welding parameters for the fuel plate assembly were obtained in terms of the accelerating voltage, beam current and welding time. The welds made by the optimum parameters showed slightly lower tensile strengths than those of the un-welded specimens. The integrity of the welds by the EBW process was confirmed by the results of the tensile test, an examination of the macro-cross sections and the fracture surfaces of the welded specimens.
Research and Application of Modular Construction Schemes for Containment Steel Liner of Nuclear Power Station
Authors: Lu Qinwu , Cai Hui , Liu Shaosong , Li Jiabao
Published: February 2014

By referencing the advanced concepts of other countries, we have carried out systematic research on modular construction of containment steel liner of CPR1000 NPP, including modular scheme, spreader structure, the selection of hoisting equipment, have completed the design of the module, spreader and construction scheme, and have applied this technology successfully in the demonstration project.
The Simulation of Low-Background Gamma Spectrometer With Clover Detector
Authors: Liu Huilan , Song Yushou , Xie Zhaoyang , Sun Baodong
Published: February 2014

A low-background gamma spectrometer consists of a high-performance gamma detector and a low-background chamber. It is widely used to monitor the radiation level of the environment and to identify the species of the radiological source. It is especially important for the analysis of the nuclear accident. Usually a high purity Germanium detector (HPGe) is used as a gamma ray detector. In order to enhance the detecting accuracy and sensitivity, it is essential to improve the performance of the gamma detector. In recent years, a clover detector composed of four coaxial HPGe crystals appear and is widely utilized in nuclear physics experimental research. Because of the larger dimensions and segmented structure, it displays outstanding characteristics different from traditional HPGe detectors. With a clover detector as the main detector and the HPLBS1 chamber of ORTEC as the lead chamber, the low-background gamma spectrometer is simulated by the Monte Carlo toolkit GEANT4, where the interaction processes of gamma ray provided by the GEANT4 physics list is used. The detecting performance of the low-background gamma spectrometer such as detecting efficiency and peak-total ratio are given. The results indicate that low-background gamma spectrometer with a clover as the main detector has better characteristic than that with HPGe as a main detector traditionally.
Algorithm of Water Film Identification in Passive Containment Water Distribution Test
Authors: Zhu Mingzhang , Chang Huajian , Wang Han , An Xu , Wang Xianmao
Published: February 2014

Water distribution test designed to study the relationship between water film coverage and water flow rate and containment structure, is an important part of the passive containment cooling test. In the process of developing CAP1400 Pressurized Water Reactor (PWR), water distribution test facility was built by SNPTRD (State Nuclear Power Technology Research & Development Center). Water distribution test facility is a separate-effect test facility, based on CAP1400 containment as the prototype. Test body contains 1/8 sector of the containment dome and a certain length (3m) vertical wall, with the ratio of 1:1 of the prototype. Water film identification algorithm is used to extract water film image information from the photo of measured area obtained by Matrix CCD and to determine the effective water film region in order to calculate the water film coverage. The starting point of designing water film identification algorithm was to find out the boundaries between water film zone and no water film region based on the gray difference. In order to ensure that the difference identification can be achieved, median filtering and mean value block were conducted on gray value matrix to remove high-frequency fluctuations in the gray value curve. The algorithm was implemented with MATLAB and sensitivity studies were performed to investigate the effects of block size and difference magnitude on the identified coverage of water film. It was found out that block size and difference magnitude had little influence on the identification of water film coverage. According to the corresponding degree between identified images and original photos, 2-by-2 block and gray-difference function were selected in the algorithm. Then the program identified results were compared with artificial identified results, the results showed that: water film identification algorithm can identify water film effectively. Coverage deviation between calculated and artificial identified results is less than 5%, and nearly not affected by brightness, laying foundation for the analysis of water distribution test.
The Development of a Mechanistic Model of MCCI Under Severe Accidents
Authors: Wei Wei , Qi Kelin , Shan Fuchang , Chen Yanfang , Guo Fude
Published: February 2014

This paper describes a mechanistic model of the molten core-concrete interaction (MCCI) process under severe accidents, and selects the Daya-Bay nuclear power plant as the research object to calculate and analyze the process of the MCCI when the station blackout (SBO), or loss of coolant (LOCA) severe accident serial is happened. The calculation results of this procedure are compared with the large-scale analysis programs MELCOR to verify the reasonableness and correctness of the model. The results indicate that the model present in this paper can simulate the MCCI process correctly and reasonably under multi-serial severe accidents.
Reflections and Suggestions on the Inspection Qualification System Development in China Nuclear Power Industry
Authors: Zhong Zhimin , Li Jinsong
Published: February 2014

This paper briefly introduces the history, development, aims and roles, state of the art of Inspection Qualification in nuclear power industry in developed countries, such as US and UK. Then, the author reviewed the related works in China in past years and the state of art, the challenges and reflections of building China inspection qualification system. Furthermore, based on the actual situation in China, combined with the advantages and disadvantages of European Inspection Qualification system and ASME Performance Demonstration method, the author put forward some suggestions on organization, system and related technical basis to promote the establishment and development of inspection qualification system in China. It was obvious that the inspection qualifications have to be taken before nuclear power plant pre-service inspection or in-service inspection. The inspection qualification system shall be developed as soon as possible and it will improve nuclear power plants safety operation in China.
Burnup Credit in the Criticality Safety Analysis of Spent Fuel in Transportation and Storage Systems
Authors: Soloviov Vladyslav
Published: February 2014

In this paper accounting of spent nuclear fuel (SNF) burnup of RBMK-1000 only with actinides has been performed.

The following characteristics were analyzed: initial fuel enrichment, burnup fraction, axial burnup profile in the fuel assembly (FA) and fuel weight.

As the results show, in the first 400 hours after stopping the reactor, there is an increase in the effective neutron multiplication factor (keff) due to beta decay of 239Np into 239Pu. Further, from 5 to 50 years, there is a decrease in keff due to beta decay of 241Pu into 241Am. Beyond 50 years there is a slight change in the criticality of the system.

Accounting for nuclear fuel burnup in the justification of nuclear safety of SNF systems will provide an opportunity to increase the volume of loaded fuel and thus significantly reduce technology costs of handling of SNF.
Numerical Investigation of Two Phase Flow and Heat Transfer Characteristics of Passive Containment Cooling System
Authors: Deng Jia-Jia , Pan Liang-Ming , Kang Mei-Qiang
Published: February 2014

The heat transfer characteristics of passive containment cooling system (PCS) are very important to protect the nuclear reactor from early release in some severe accident scenarios. In this paper, based on the natural convection and the VOF (Volume of Fluid) multiphase model, the two-phase flow and heat transfer characteristics of the water film of PCS at postulated accident was numerically investigated. To economize the calculation resource, a two dimensional axis symmetry cooling system was included in the simulation model owing to the symmetry of the system. The transportation of mass and energy during the phase change at film interface was established by adding source terms to the mass and energy equations with User Defined Function (UDF). Because of the lower heat capacity of the cooling gas, the air flow rate and flow pattern of natural convection were the governing factor of the heat transfer through containment. Generally, the heat transfer rate is very lower because the heat and flow attached layer at air baffle and water film are very thick due to the flat plate air baffle, but stronger vortex produced by air baffle will reduce the heat transfer because of damage of the water film. The dimensions and the shape of the air baffle have important effect on air flow rate and flow pattern of the natural convection, and the optimal option was chosen based on the simulation results.
Measurement of Inhaled Uranium Using Lung Counting System
Authors: Cheng Zhiwei , Shen Maoquan , Zhang Yang , Zou Ronghu , Li Xianli
Published: February 2014

The coefficient of detector efficiency is an essential while we use lung counting system to assess the internal exposure dose. This paper used an anthropomorphic phantom which was made accordance with Chinese Reference Man to calibrate our system. We cooperated with China Institute for Radiation Protection to manufacture the phantom which was made of tissue equivalent materials. In the lung there are 246 club-shaped uranium sources. Each source includes (20.12±0.32) Bq 238U and (0.53±0.01) Bq 235U. There are 4 parts in this paper. We start with a brief introduction to our lung counting system. Then the method of how to manufacture the lung and the result of the parameters such as density, linear absorption coefficient of the lung are provided in detail. The efficiency curve under different Chest Wall Thickness (CWT) is obtained. In our application, about 22 workers have been measured finally. We find in our research that the Minimum Detectable Activity (MDA) of natural uranium changes from 2.5mg to 5.9mg as the CWT varies from 16.2mm to 40.5mm for our lung counting system in 4000s detecting time by analyzing 63.3keV photo-electricity peak of gamma ray. Based on the least limited value of annual inhalation is about 220mg while the lung slowly absorbed uranium aerosol with particles about 1 μm, we may conclude that our lung counting system can be well used to detect the activity of natural uranium in a short time after a worker inhaled uranium aerosol.
Scaling for Different Containment Passive Cooling Design Under LOCA Conditions
Authors: Li Shengqiang , Xiong Yin , Hao Yalei , Jiang Shengyao
Published: February 2014

The containment passive cooling feature is one important indicator for advanced Pressurize Water Reactors (PWRs). Several innovative passive cooling designs have been proposed in industries, such as double steel cooling structure (DSS) in AP1000, the Vertical Heat exchanger in VVER, the water cooling wall in High Temperature Reactor (HTR), and ice cooler in some Generation II PWR plants. A universal passive cooling experimental facility is under design and construction. The object of this facility is performance testing and optimization of new passive cooling facilities. Considering of the diverse characteristics of the different passive cooling system, include mechanism of heat and mass transfer, conditions for operation and facility structures, a theoretical scaling study is necessary to be applied before a technical design process. Some general passive cooling models were made based on existing industrial designs. To enhance the compatibility of these models and future designs, pivotal and common parameters for these passive cooling designs were provided by scaling study. The main test facility will be built based on these parameters. For every different design, special appurtenances will be added to the main facility to complete the test device for special purposes. Time scale, facility height and physical properties were the most important parameters for the main test facility. Heat transfer area ratio, hydraulic diameter, volume flow rate and wall thickness of DSS was defined for appurtenances design.
Dynamic Balance and Vibration Control on Field of the Fan L9DVN272ZV in Lingao Nuclear Power Plant
Authors: Dong Xiangxiang , Li Zhaojie
Published: February 2014

Dynamic balancing is an effective measure for adjusting an unbalanced fan rotor mass to within its allowable limits. This is a typically implemented method used in nuclear power plants for resolving fan rotor unbalance conditions.

The operating spectrum of L9DVN272ZV has always been the fundamental component of the vibration frequency since finding the fan high vibration. This paper discusses the balance process of the subject fan. The vibration data collected was evaluated to aid in selecting the proper method of vibration attenuation. Ultimately the fan vibration was reduced to within the specified allowable limits.
Development of a Thermal-Hydraulic Code for Chinese Helium-Cooled Ceramic Breeder TBM Cooling System
Authors: Wang Jie , Su Guanghui , Tian Wenxi , Qiu Suizheng
Published: February 2014

Helium was chosen as the coolant for divertor cooling loop, Korea helium cooled solid breeder TBM, European helium cooled pebble bed TBM and Chinese helium cooled ceramic breeder TBM. The thermal-hydraulic analysis for the divertor cooling loop and the TBM cooling systems were carried out by RELAP5 and MELOCR codes, which were developed for transient simulation of light water reactor coolant system during postulated accidents. In this study, a thermal-hydraulic and safety analysis code (TSACO) for helium cooling system was developed and calculation of the Chinese HCCB TBM cooling system was presented. Heat transfer and flow friction models for helium were added in the code. First, the code was verified by comparing with the RELAP5 code with the same initial and boundary conditions. The first wall temperature, pressure drop and inlet/outlet temperatures were studied and a good agreement was obtained, then ex-vessel loss of coolant accident for Chinese HCCB-TBM cooling system was investigated using TSACO. The results show that the TBM can be cooled efficiently and the TCWS pressure stays within the design limits with a large margin.
Neutron Image Restoration by Combining Richardson-Lucy With Steering Kernel
Authors: Qiao Shuang , Wang Qiao , Huang Jipeng
Published: February 2014

Neutron image obtained from a small digital neutron imaging system, always has characteristics of low contrast, blurred edges and serious noise. It is disadvantageous to further analyse information about the sample’s internal structure, so it is essential for the observer to process the degraded image to improve its visual quality. In order to avoid the noise amplification problem of the original Richardson-Lucy (R-L) algorithm, which is adopted to recover degraded image, a restoration algorithm by combining R-L algorithm with Steering Kernel (S-K) algorithm for neutron image is presented in this paper. First S-K algorithm is applied to restrain the noise of the blurred noisy neutron image, as well as improving the signal-to-noise ratio of the image, and then R-L algorithm is used to reconstruct the blurred noisy image. The proposed algorithm is able to make up for the deficiency of R-L algorithm in dealing with the noise amplification problem, which is caused by the repeated iteration, while retaining the details of the image characteristics as much as possible. Comparative experimental results show that the algorithm can obtain satisfactory restoration visual effect for neutron image. The details of the work done are described in this paper.
A Method for RCCA Drop Analysis
Authors: Liu Tong , Huang Heng , Li Peng , Xu Wei , Zhou Yuemin , Yang Yiren
Published: February 2014

The control rod drop time is one of the most important parameters for safety analysis. The calculation accuracy of control rod drop time will be affected if ignoring the transverse vibration, which is mainly caused by the fluid-structure interaction between the RCCA (rod cluster control assembly)s, guide tubes and the fluid interaction.

A new method for RCCA drop analysis is presented in this paper. The transverse equations of motion are established considering fluid-elastic structure interaction, assuming the fluid is incompressible laminar flow. And the vertical equations of motion are established considering the gravity force of RCCAs, the fluid resistance, and the friction force led by collision.

A computer program based on this method is used to calculate the control rod drop time, the impact and the dynamic response of RCCA. The analysis results are compared with those of the in-house code, which is used for commercial design. It shows the computer program using the new models provides a useful tool in the design of RCCAs and fuel assemblies.
COSINE Validation Experiment Plan: 1st Phase
Authors: Liu Lifang , Fu Xiaoliang , Du Zheng , Yu Nan , Yang Yanhua
Published: February 2014

COSINE (COre and System INtegrated Engine for design and analysis) is the software platform for nuclear power plant design and analysis being developed in China, which contains three thermal-hydraulics codes and three physics codes in the first phase of this project. Three thermal-hydraulics codes in COSINE are sub-channel code, system analysis code, and containment analysis code. Separate experiments data and integral experiments data are needed to validate the models and analyze the uncertainty of these codes. Some data are obtained from international database and organizers. At the same time, an experiment plan has been made by SNPSDC to meet the COSINE thermal-hydraulics codes validation requirements. In the 1st phase of this plan, eight separate effects facilities are being constructed to get some valuable data from January 2011 to December 2014, and the test contents has been programmed. The facilities, contents and the schedules of the tests of COSINE validation experiment plan-I are detailed in this paper.
Experimental Investigations of Control Rod Drive Mechanism
Authors: Lu Guangyao , Lu Zhaohui , Xiang Wenyuan , Lv Yonghong , Huang Wenyou , Zhou Jianming
Published: February 2014

The control rod drive mechanism (CRDM) is installed on the CRDM socket in reactor pressure vessel (RPV). Directed by Rod Control and Rod Position Indicating System (RGL), CRDM can impel the control rods move up and down in the nuclear reactor core, which implements the functions of reactor start-up, power regulation, power maintaining, normal reactor shutdown and abnormal (accident) shutdown.

CRDM was developed by China Nuclear Power Research Institute (CNPRI). Several design improvements were conducted to solve the problems appeared in the operation of nuclear power station. Test bench was also set up and cold tests were carried out to investigate the characteristics of CRDM. The cold tests included lifting experiment, inserting experiment, rod drop experiment. And studies were carried out to analyze the signals of lifting coil, moving coil, stationary coil and the vibration signals. The test results show that the design of CRDM is reasonable and the operation is reliable.
The RCM Technique Application in NPP Operation and Design Stage
Authors: Lifei Yang , Hong Jiang
Published: February 2014

The national nuclear safety regulation commands that the safety, reliability and economy of the NPP must be considered in design and operation stage. In order to reach the goal, the paper firstly introduces how to use the RCM technique to make preventive maintenance programs to ensure the safety and reliability of the NPP which is in service or under construction, and then elaborates how to take the RCM technique into design in the early phase, to promote the safety and reliability of the NPP. It has been considered that RCM technique shows a positive role in the whole process, not only improving the maintenance manage level, but also the safety and reliability at the design stage.
Zero Thickness and Reference Demarcating Method for the Deposition Detection of Corrosion Products in PWR Primary System
Authors: Cheng Xiaolei , Yu Qian , Liu Fang , Ouyang Xiaoping
Published: February 2014

A nondestructive detection method based on radiation detecting technology has been design to inspect the deposition of corrosion products in Pressurized Water Reactor (PWR) Primary system. The zero thickness and reference demarcating method could measure the thickness of the corrosion products deposited inside the pipeline without the γ attenuation coefficient of the pipeline, coolant and the corrosion products which are necessary in the normal Nondestructive detection yet hard to be controlled and accurately obtained. With this method, the wall thickness and the inner diameter of the pipeline are not required during detection. The thickness of the corrosion products could be measured by only five parameters which could be monitored on-site real time: the gamma intensity at Measured Angle I, the gamma intensity at standard angle I0′, the length of the demarcating sample Z, the gamma intensity through the sample of corrosion products Ip and the gamma intensity through the sample of coolant Ic. With this method, the space distribution of the corrosion products inside the pipeline could be measured outside intuitively and conveniently. This method could also be applied to research the transport mechanisms of corrosion products in PWR Primary system, as the reference of the study on Primary water chemical.