bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental Investigation of Boil-Off-Scenario in BWR Spent Fuel Pools
Authors: Schulz Steffen , Schuster Christoph , Hurtado Antonio 
Published: February 2014

Accident scenarios in spent fuel pools (SFP) were not a main topic in nuclear safety studies so far. Heat fluxes are low and the timeframe for counteractions in case of a loss of cooling is long. However, because of their huge activity inventory safety of spent fuel pools should be analyzed with great intensity. Beside some analytical approximations from the U.S. Nuclear Regulatory Commission (NRC) there is only few experimental data about loss of coolant accidents in a SFP [1, 3, 4, 5, 6]. After the reactor accident in Fukushima Daiichi NPP this issue became omnipresent in public perception. The presented paper investigates boil-off scenario of a boiling water reactor (BWR) SFP after a station blackout with focus on experimental findings.
Since 2006 experiments for SFP boil-off scenarios were conducted at the Technische Universität Dresden [7]. For a detailed investigation under realistic geometrical fuel assembly conditions the test facility ADELA-II was built in 2011. It consists of two channels. The inner channel simulates a quarter of a BWR fuel element with a 24 rod bundle. In the outer channel 8 more heating rods were assembled to reduce heat losses from the inner channel and to simulate the surrounding. With a heated length of 3760 mm and a width of 120 mm it was designed in an axial and radial scale of 1:1. The heating profile is based on the heat flux profile of a fuel rod with low burn-up. To measure the detailed axial and radial temperature profiles 113 thermocouples are mounted. With these data conclusions for heat and mass transfer can be made with special regard to convection inside the assembly. Boil-off experiments at the ADELA-II facility with a supplied heat of 20 Watts per rod lead to rod surface peak temperatures of about 479 °C. Due to the high temperature and narrowed geometry the axial heat transport is harmed and radial heat conduction had a great influence on the test results. Accordingly, quasi adiabatic boil-off could not be verified. Thus, coolability of a fuel assembly strongly depends on the (radial) heat removal from the fuel assembly box to the surrounding. Further investigations have to be done for a better consideration of neighbored fuel elements and global thermohydraulic effects in the spent fuel pool.
Risk Insights and Use Based on Fukushima Accident
Authors: Chapman James R. , Fine K. Raymond , Grantom C. Rick 
Published: February 2014

A beyond design basis event resulted in severe core damage at 3 units at Fukushima Dai-iche. In response the International community identified lessons learned, conducted initial stress tests, and requested nuclear power plant operators to conduct additional evaluations and act on the results of these evaluations. In the US actions have included development of enhanced strategies to deal with an extended loss of offsite power or the ultimate heat sink, design and procurement of portable equipment to support core cooling indefinitely, and external hazard evaluations. The key external hazard evaluations are related to external flooding and seismic hazards.
In addition to directed evaluations, NRC, ASME and NEI are pursuing refinements to the risk informed approach to decision making. The use of PRA in a risk informed decision making process, combined with defense in depth and safety margin considerations, has expanded considerably in the past two decades. So the questions addressed in this paper are: Why expand this approach further? How are PRA and traditional practices balanced? And what is the outcome if we do not expand this approach?
The insights are based on the ongoing activity by NRC to address Near Term Task Form (NTTF) Recommendation 1 [1,2] NUREG-2150 [3] which proposes a more risk informed regulatory process, ASME [4] and Industry activity lead by the Nuclear Energy Institute (NEI) [5]; and past and ongoing uses of PRA.
In summary, the paper concludes that an improved and increased use of a risk informed process is appropriate so as to better address lessons learned from the events at Fukushima, to better understand and act on limiting plant features (“vulnerabilities”), and have a framework in place to address any future beyond design basis events or new information more coherently.
A key lesson learned from Fukushima Dai-ichi is that PRA can identify vulnerabilities which can be acted on to reduce the potential for loss of another plant. But this requires the International community to embrace PRA, and to date the International community has not. This is because most in the Industry rely on checklists and are challenged to envision low frequency high consequence events.
A Research on Eliminating the Deposited Water After Water-Ingress Accident in HTR
Authors: Liu Peng , Zheng Yanhua 
Published: February 2014

Water-ingress accident, caused by steam generator heating tube rupture of a high temperature gas-cooled reactor (HTGR) is an important accident to consider because it will introduce positive reactivity leading the nuclear power increase rapidly, as well as the chemical reaction of graphite fuel elements and reflector structure material with steam. Researches and simulations (Zuoyi Zhang et al. 1995; Zheng Yanhua et al. 2009) have been carried out for calculating the total amount of water ingress and to validate the safety and security of HTR. The water ingress amount, which is our mainly concerned, ranges from a few hundred kilograms to thousands of kilograms, because of the different reactors and different computing methods. The place, where the water deposits, is most likely to be the bottom of the steam generator.. Such liquid water removal, with the approach of providing a forced circulation in primary loop and accelerating the evaporation, is analyzed in this paper.
Many experimental data have been got on water evaporation rate (Dalton et al.; Willis Carrie et al. 1914; Yoshida, Hyodo et al. 1970; Sweer et al. 1976; Pauken et al. 1995). All these formulas have a common form, ṁ = hc(Pw − Pa)/hw, which shows the relationship between evaporation rate and velocity over water face, water temperature and the relative partial pressure of the water vapor. This formula has been used widely in chemical industry and other fields and shows good agreement.
FLUENT CFD code (ANSYS Fluent 14) is used for the calculation of the distribution of the flow and temperature fields. The evaporation rate is estimate combined thermal fluid data with empirical formula. As the working condition of empirical formula and that of actual reactor don’t match very well, sensitivity analysis is necessary in this report.
Feasibility Study of Utilizing TRISO Fuel in PWR Technology
Authors: Hussain Anwar , Khan Ammar 
Published: February 2014

The aim of this paper is to summarize the research that has already been conducted in the field of PWR technology which utilizes TRISO fuel (Tri-Structural Isotropic) instead of standard PWR fuel. TRISO fuel which in mainly used in HTGRs has been used in SMRs. This type of reactor can be a potential source of energy for a limited power production, heating and desalination facilities at remote location. Combination of TRISO fuel and PWR technology results in a reliable and safe NPP design. Due to enhanced and outstanding passive safety features advanced SMRs are being studied around the world and substantial amount of conceptual research has already been conducted in this field. However, further research is required to be undertaken to optimize these design concepts.
Finally, few areas have been pointed out for further research to overcome the challenges and gaps in this research field.
Ventilation Management for the AP1000 Containment Building During Construction Stage
Authors: Sun Zhiyou , Shen Hongwei 
Published: February 2014

Confined space can be defined as closed or semi-closed equipments, facilities and places which potentially have poor ventilation, poisonous and hazardous gases or poor oxygen. Confined space has complex working environment and more hazardous factors which makes safety accidents occurred frequently. Modularized Construction, as the typical feature of AP1000 nuclear project construction, shortens the construction schedule but increases safety risk, since there is more confined space and cross work, especially in the Containment building after the setting of CVTH.
This thesis analyses the confined space construction feature of the containment building and emphasizes the necessity of ventilation and fume control. Some ventilation methods have been taken on site which has effectively reduced the construction risk inside containment buildings. Therefore, this thesis has practical value for the consequent AP1000 project construction.
Estimation of Fukushima-Daiichi NPS PCV Cooling States Based on Measurement Data After Nitrogen Injection
Authors: Ichikawa Ryoko , Masuhara Yasuhiro 
Published: February 2014

The cooling states in the PCV are not clear after the TEPCO’s Fukushima Daiichi NPS accident. But from the standpoint of the long-term stability cooling, the understanding of the PCV cooling condition is important.
Therefore, the simple method was developed in which the PCV water and gas leak diameters and those locations, etc. could be estimated based on the time transient data. By applying this method to Fukushima Daiichi NPS accident after the nitrogen injection for prevention of the hydrogen explosion, the PCV leak locations, diameters and partial pressures, etc. were estimated.
It was found that the partial pressure of hydrogen and oxygen was kept low and the nitrogen injection to PCV was effective as a prevention of hydrogen explosion. The decay heat from the fuel was mainly removed by the sub-cooling water injected and steam condensation on the PCV wall. The heat release by leakage was estimated to be small.
Application of Cloud Chambers for Heuristic Comprehension of Radiation
Authors: Tawara Yuzuru , Hara Shinji , Koga Kazuo , Tsuji Kenji 
Published: February 2014

In the nuclear-related public relation center, a variety of displays such as models of nuclear facility, panel presentations to explain radiation properties, radiation detectors are used for the visitors to help the understanding of nuclear power and radiation. The PR center demonstrates various aspect of the radiation such as the presence of natural background radiations around us in the daily life, shielding effect for the different kind of radiations. Cloud Chambers are often used to demonstrate the presence of natural background radiation, showing tracks caused by the ionizing effect. The shielding effect of radiation is demonstrated by inserting a shield material between a radiation source and the detector such as GM counter. It is usually illustrated in the panel that the penetration properties are different for kinds of radiation but actual demonstration is seldom used.
Then a question arises that people cannot properly understand overall characteristics of the radiation in the above described demonstrations in the PR center. So we have been trying to improve a utilization method of a cloud chamber to help the deep understanding of properties of radiation. The improved cloud chamber has the area size of 225 mm × 225 mm with 100 mm in depth and has the structure for the function of insertion and extraction of both a radiation source and a shield material, independently. When a radiation source such as Cs-137 or Fe-55 is inserted in the chamber, it is clearly shown that high energy electron created by gamma-ray or X-ray emitted from such radioisotope can make track with different length. It is also shown using lantern core with thorium-series isotopes that thick track can be made by alpha particle. Fe-55 radioisotope generates 5.9 keV X-rays, which produces about 1mm track in the chamber through photoelectron.
When a shield material of lead with a thickness of 1mm was inserted in front of the source, the fading out of the tracks is clearly observed. Thus shielding effect can be easily confirmed by eye using cloud chamber. The demonstrations of shielding effect described above can help more clear and essential understanding of the radiations. This was shown by the questionnaire survey done before and after the demonstrations for the 32 participants.
For further improvements of the cloud chamber, we are planning to enlarge the size of cloud chamber and to get much clearer track image by improving track illumination method. Finally we will re-consider more effective explanation to give correct understanding of the radiation and will verify the effectiveness of utilization method of new cloud chamber.
Levels and Patterns of Daily Physical Activity and Sedentary Behavior Measured Objectively in Older Care Home Residents in the United Kingdom
Authors: Barber S.E. , Forster A. , Birch K.M. 
Published: February 2014

Background:Physical activity is important for maintaining independence and quality of life in older people living in care homes. Little is known about patterns of physical activity or sedentary behavior in this population.Methods:Thirty-three care home residents (82.6 ± 9.2 years) wore an ActiGraph GTX3 accelerometer for seven days, which provided minutes of sedentary behavior and low, light, and moderate-to-vigorous physical activity. Participants undertook the Mini-Mental State Examination and care staff reported activities of daily living (Barthel index) and functional ambulation classification (FAC) for each participant.Results:Participants spent on average 79% of their day sedentary, 14% in low, 6% in light, and 1% in moderate-to-vigorous physical activity. Activity levels did not significantly differ between days or hours of the day (P > .05).Conclusion:Levels of physical activity were very low and time being sedentary was high. This study can inform physical activity and sedentary behavior interventions for care homes’ residents.
Whole-Genome Shotgun Assembly and Analysis of the Genome of
Shiraia
sp. Strain Slf14, a Novel Endophytic Fungus Producing Huperzine A and Hypocrellin A
Authors: Yang Huilin , Wang Ya , Zhang Zhibin , Yan Riming , Zhu Du 
Published: February 2014

ABSTRACT

Here, we report the draft genome sequence of
Shiraia
sp. strain Slf14 (China Center for Type Culture Collection [CCTCC] no. 209294), which is used to produce huperzine A and hypocrellin A. The genome sequence will allow for the characterization of the molecular mechanisms underlying its beneficial properties.
Genome Sequence of Legionella anisa, Isolated from a Respiratory Sample, Using an Amoebal Coculture Procedure
Authors: Pagnier Isabelle , Croce Olivier , Robert Catherine , Raoult Didier , La Scola Bernard 
Published: February 2014

ABSTRACT

Legionella anisa
is a gammaproteobacterium from the class
Legionellaceae
, which is responsible for nosocomial pneumonia. We sequenced the genome from the
L. anisa
strain Linanisette, which was recovered from a clinical sample using an amoebal coculture procedure but not with standard culture methods.
Draft Genome Sequence of Clostridium ultunense Strain BS (DSMZ 10521), Recovered from a Mixed Culture
Authors: Wei Yongjun , Zhou Haokui , Zhang Lei , Zhang Jun , Wang Yuezhu , Wang Shengyue , Zhou Zhihua , Yan Xing 
Published: February 2014

ABSTRACT

Clostridium ultunense
BS is the first isolated strain (type strain) of
C. ultunense
that was identified as a mesophilic syntrophic acetate-oxidizing bacterium (SAOB). Here, we report the draft genome sequence of this strain, which will help us to elucidate the mechanism of syntrophic acetate oxidization.
How well do doctors think they perform on the General Medical Council's Tests of Competence pilot examinations? A cross-sectional study
Authors: Mehdizadeh Leila , Sturrock Alison , Myers Gil , Khatib Yasmin , Dacre Jane 
Published: February 2014

ObjectiveTo investigate how accurately doctors estimated their performance on the General Medical Council's Tests of Competence pilot examinations.DesignA cross-sectional survey design using a questionnaire method.SettingUniversity College London Medical School.Participants524 medical doctors working in a range of clinical specialties between foundation year two and consultant level.Main outcome measuresEstimated and actual total scores on a knowledge test and Observed Structured Clinical Examination (OSCE).ResultsThe pattern of results for OSCE performance differed from the results for knowledge test performance. The majority of doctors significantly underestimated their OSCE performance. Whereas estimated knowledge test performance differed between high and low performers. Those who did particularly well significantly underestimated their knowledge test performance (t (196)=−7.70, p<0.01) and those who did less well significantly overestimated (t (172)=6.09, p<0.01). There were also significant differences between estimated and/or actual performance by gender, ethnicity and region of Primary Medical Qualification.ConclusionsDoctors were more accurate in predicating their knowledge test performance than their OSCE performance. The association between estimated and actual knowledge test performance supports the established differences between high and low performers described in the behavioural sciences literature. This was not the case for the OSCE. The implications of the results to the revalidation process are discussed.
Anthropometric measurements of general and central obesity and the prediction of cardiovascular disease risk in women: a cross-sectional study
Authors: Goh Louise G H , Dhaliwal Satvinder S , Welborn Timothy A , Lee Andy H , Della Phillip R 
Published: February 2014

ObjectivesIt is important to ascertain which anthropometric measurements of obesity, general or central, are better predictors of cardiovascular disease (CVD) risk in women. 10-year CVD risk was calculated from the Framingham risk score model, SCORE risk chart for high-risk regions, general CVD and simplified general CVD risk score models. Increase in CVD risk associated with 1 SD increment in each anthropometric measurement above the mean was calculated, and the diagnostic utility of obesity measures in identifying participants with increased likelihood of being above the treatment threshold was assessed.DesignCross-sectional data from the National Heart Foundation Risk Factor Prevalence Study.SettingPopulation-based survey in Australia.Participants4487 women aged 20–69 years without heart disease, diabetes or stroke.Outcome measuresAnthropometric obesity measures that demonstrated the greatest increase in CVD risk as a result of incremental change, 1 SD above the mean, and obesity measures that had the greatest diagnostic utility in identifying participants above the respective treatment thresholds of various risk score models.ResultsWaist circumference (WC), waist-to-hip ratio (WHR) and waist-to-stature ratio had larger effects on increased CVD risk compared with body mass index (BMI). These central obesity measures also had higher sensitivity and specificity in identifying women above and below the 20% treatment threshold than BMI. Central obesity measures also recorded better correlations with CVD risk compared with general obesity measures. WC and WHR were found to be significant and independent predictors of CVD risk, as indicated by the high area under the receiver operating characteristic curves (>0.76), after controlling for BMI in the simplified general CVD risk score model.ConclusionsCentral obesity measures are better predictors of CVD risk compared with general obesity measures in women. It is equally important to maintain a healthy weight and to prevent central obesity concurrently.
The case of the whelping bitch
Authors: McCulloch Steven 
Published: February 2014

THIS series gives readers the opportunity to consider and contribute to discussion of some of the ethical dilemmas that can arise in veterinary practice. Each month, a case scenario is presented, followed by discussion of some of the issues involved.In addition, a possible way forward is suggested; however, there is rarely a cut‐and‐dried answer in such cases, and readers may wish to suggest an alternative approach. This month's dilemma, ‘The case of the whelping bitch’, was submitted and is discussed by Steven McCulloch. Readers with comments to contribute are invited to send them as soon as possible, so that they can be considered for publication in the next issue. Discussion of the dilemma ‘Dealing with dark desires’, which was published in the January issue of In Practice, appears on page 103.The series is being coordinated by Siobhan Mullan, of the University of Bristol. It is hoped it will provide a framework that will help practices find solutions when facing similar dilemmas.
Heavy mineral record of Andean uplift and changing sediment sources across the NE margin of South America: a case study from Trinidad and Barbados
Authors: Vincent Hasley , Wach Grant , Ketannah Yawooz 
Published: February 2014

Abstract
The heavy mineral compositions of sandstones in Trinidad and Barbados record the onset of Andean-related erosion and a reduction of craton-derived sediments into NE South America. The changing provenance was deduced by comparing heavy mineral assemblages interpreted from ancient sandstones with associations recognized in modern sands that can be reasonably correlated to existing tectonic domains. The impact of the Andean orogeny across the margin was to introduce a suite of minerals characteristic of low-temperature metamorphism that today is prevalent adjacent to the Caribbean Mountain belt and differs from the zircon-rich assemblage produced within cratonic plains. Twenty-one Paleocene–Late Pliocene sandstone samples from Trinidad revealed systematic changes in mineral diversity and maturity that recorded this provenance transition, and suggests Andean erosion during deposition of the Late Oligocene Nariva Formation. Similar to Palaeogene sandstones of Trinidad, four Eocene Scotland Formation samples from Barbados support craton derivation, but with additional evidence of minor Andean input probably due to the proximity of the Scotland Formation delivery systems to an earlier uplift episode. By the Late Miocene, most of the sediments delivered into Trinidad basins were supplied from the Andean orogeny as suggested by the relative abundance of minerals of this affinity. The heavy mineral records of Trinidad and Barbados are similar to that described across northern South America from both modern and ancient environments that collectively mark the uplift of the Andean mountain belt, with its strong influence on drainage patterns and reservoir provenance along this sector of the continental margin.

Supplementary material:

Sample location coordinates, sample and outcrop photographs, and summary outcrop sections are available at
http://www.geolsoc.org.uk/SUP18728
.