bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental Investigation on Dependence of Decontamination Factor on Aerosol Number Concentration in Pool Scrubbing Under Normal Temperature and Pressure
Authors: Sun HaoMin , Machida Shinichi , Sibamoto Yasuteru , Okagaki Yuria , Yonomoto Taisuke 
Published: October 2018

During a severe accident of a nuclear reactor, radioactive aerosols may be released from degraded nuclear fuels. Pool scrubbing is one of the efficient filters with a high aerosol removal efficiency, in other words a high decontamination factor (DF). Because of its high performance, many pool scrubbing experiments have been performed and several pool scrubbing models have been proposed. In the existing pool scrubbing experiments, an experimental condition of aerosol number concentration was seldom taken into account. It is probably because DF is assumed to be independent of aerosol number concentration, at least, in the concentration where aerosol coagulation is limited. The existing pool scrubbing models also follow this assumption.
In order to verify this assumption, we performed a pool scrubbing experiment with different aerosol number concentrations under the same boundary conditions. The test section is a transparent polycarbonate pipe with an inner diameter of 0.2 m. 0.5 μm SiO2 particles were used as aerosols. As a result, DF was increasing as decreasing the aerosol number concentration. In order to ensure a reliability of this result, three validation tests were performed with meticulous care. According to the results of these validation tests, it was indicated that DF dependence on the aerosol concentration was not because of our experimental system error including measurement instruments but a real phenomenon of the pool scrubbing.
Detailed Experimental and Analytical Study on Long Two-Phase Closed Thermosiphons Related to Passive Spent-Fuel Pool Cooling
Authors: Graß Claudia , Krüssenberg Anne , Kulenovic Rudi , Weyermann Fabian , Starflinger Jörg , Schaffrath Andreas 
Published: October 2018

New concepts are currently being discussed for passive residual-heat removal with heat pipes from spent-fuel pools and wet-storage facilities. Because of their high heat-transport capability and their simple design, two-phase closed thermosiphons have a great potential to satisfy the demands of a reliable and independent passive heat removal. The geometry of spent-fuel pools and the potential incorporation into existing plants requires thermosiphons of at least 10 m in length including bends. Such thermosiphons are neither available nor have they been investigated yet. Therefore, experimental and numerical investigations are being carried out.
At IKE the basic operational behavior of 10-m-long thermosiphons with water — as working fluid — are being experimentally investigated. Measurements for different pipe diameters (32 mm and 45 mm) are performed at various heat sink temperatures (10 °C, 20 °C and 30 °C), heat inputs (1000 W to 4000 W), and filling ratios (50%, 70% and 100%).
GRS is developing codes, such as AC2, in order to simulate all relevant phenomena within a nuclear power plant during normal operation, incidents, accidents, and severe accidents. Regarding passive residual-heat removal with thermosiphons, the models of AC2 are being improved to properly simulate the thermos-hydraulics of this heat transfer process. Starting with the module ATHLET (Analysis of Thermal-hydraulic of Leaks and Transients), the applicability of its existing models is checked for modeling long thermosiphons and calculating their operational behavior. The main model improvements are being validated against the new experiments of IKE.
External Hazard Coinciding With Small Break LOCA Thermohydraulic Calculation With System Code ATHLET
Authors: Kosowski Kai , Seidl Marcus 
Published: October 2018

The safety behaviors of a NPP after an external hazard-initiated event, as well as after a small break LOCA are already well known as part of the analyses done for standard licensing. In this paper, a combination of both event categories is investigated by means of the thermohydraulic system code ATHLET (analysis of the thermohydraulics of leaks and transients) developed by the Gesellschaft für Anlagen- und Reaktorsicherheit (GRS, Germany). The scenario assumes an external event with a loss of coolant accident caused by induced vibrations on a small pipe attached to the primary circuit, although all pipes are designed to withstand the loads created by such an external event. The coincidence of both events leads to a beyond-design basis consideration. Furthermore, in the context of both robustness and enveloping analyses, the unavailability of both the internal power supply via the external grid connection and the emergency diesel power supply due to the external impact is postulated. For emergency cooling, the NPP in the scenario considered has only access to the passive accumulators and to systems supplied via the safeguard emergency diesel engines (2nd quartet of emergency diesel engines) — a design feature of the Siemens KWU type PWRs —, which are housed in the bunkered emergency feed building and operate with lower voltage levels.
The scenario is exemplarily modeled and simulated with ATHLET. The manner of the external event itself is not in focus, but rather the thermohydraulic behavior of the NPP is considered in the reported analysis. Beside the model assumptions and the boundary conditions, the accident sequence is explained in detail. It turns out that the remaining systems for emergency cooling are able to handle the LOCA under such demanding boundary conditions. Most importantly, the primary pressure can be lowered below the zero flow pump head of the pool cooling pumps. The long-term cooling can thereby be ensured. Furthermore, the heat removal out of the core is always sufficient.
Overall it can be concluded that all safety protection objectives have been complied for this beyond-design basis scenario.
Welded Joint Evaluation for Chromium Controlled Carbon Steel Piping to Improve FAC Resistance
Authors: Uemoto Yoshio , Kawabe Takahiro , Shibata Hiroyuki , Tarasawa Shoh , Asano Hiroshi , Kaneda Junya 
Published: October 2018

For condensate and feed water piping in nuclear power plants, it is desired to mitigate the pipe wall thinning risk due to Flow-Accelerated Corrosion (FAC). In aspect of material selection, low alloy steels are generally applied to improve FAC resistance. However, low alloy steels are inferior to carbon steels from the point of material cost and construction efficiency due to requirement of post weld heat treatment (PWHT). On the other hand, chromium is known as the most effective element to improve FAC resistance, and it is reported that a certain improvement of FAC resistance is also expected for carbon steels by increasing chromium content to over 0.10 wt%.
Such chromium controlled carbon steels are manufactured within the chemical composition range specified by material code of carbon steels, such as ASME B&PV Code Sec.II. Therefore, the amount of alloy content is lower than those for low alloy steels. The authors expect that PWHT can also be exempted for a certain thickness range of chromium controlled carbon steels, according to the exemption condition for normal carbon steels by ASME B&PV Code Sec.III. Furthermore, the chromium controlled carbon steels are generally cheaper than low alloy steels for base materials such as pipe and plate.
However, since chromium content of normal welding materials for carbon steels is generally lower than 0.05 wt%, chromium controlled carbon steel welding materials are specially-produced material. It makes the procurability worse compared to normal carbon steel welding materials. Additionally it should be confirmed if the increased chromium content affects the soundness of welded joint.
From the above reasons, it is necessary to decide the appropriate welding materials and methods for the chromium controlled carbon steel piping, considering the procurability of welding materials and the soundness of welded joint. In this study, the authors prepared the test pieces which simulate the assumed circumferential butt welded joints, then conducted the mechanical test such as tensile, impact, bend and hardness test to evaluate the soundness of welded joints. Furthermore, the authors evaluated the chromium content distribution of welded joints by using the Electro Probe Micro Analyzer (EPMA), in order to confirm if the chromium content is maintained over 0.10 wt% within the whole expected area.
Virtual Fixture Augmentation of Operator Selection of Non-Contact Material Reduction Task Paths
Authors: Sharp Andrew , Petlowany Christina , Pryor Mitch 
Published: October 2018

Decommissioning of nuclear systems and consolidation of resulting waste remains a major hurdle for the industry. The radioactive nature of nuclear waste makes manual handling unfeasible, while teleoperation and inflexible automation also have drawbacks.
This effort utilizes virtual fixtures to augment path creation for non-contact material reduction tasks. It builds on previous Nuclear and Applied Robotics Group work with Variable Normal Surface Virtual Fixtures, which generate surfaces offset from task surfaces. Offset surfaces can then provide poses at a set orientation to task surfaces. Once the Variable Normal Surface Virtual Fixture is generated from task information, operators build a list of desired path poses. The Robot Operating System Descartes package takes the pose list and plans a smooth trajectory for task execution. Planar and cylindrical demonstrations based on experimental studies at the United Kingdom’s Sellafield site were performed. This methodology augments waste reduction by allowing flexible laser cutting routes.
An Effect of Bismuth Ion on the Reduction of Terbium Ion in Molten LiCl-KCl Eutectic Salt
Authors: Kim Beom Kyu , Park Byung Gi , Han Hwa Jeong , Park Ji Hye , Kim Won Ki 
Published: October 2018

A salt waste generated from the pyroprocess contains residual actinides and needs to be purified for recycling of the salt and waste conditioning. A co-reduction process could be considered for removal of residual actinides from the salt waste, which contains lanthanides and residual actinides. In the study, specifically, an effect of Bi(III) ion on the electrochemical reaction of Tb(III) ion was investigated in the molten LiCl-KCl eutectic with BiCl3 and TbCl3 at 773 K using electrochemical techniques of cyclic voltammetry, square wave voltammetry and open circuit chronopotentiometry. Tb(III) has a single redox couple without Bi(III). However, the cyclic voltammograms obtained at tungsten electrode in LiCl-KCl-BiCl3-TbCl3 showed four redox couples. The square wave voltammogram in same condition also showed five reduction peaks. Cyclic voltammogram and square wave voltammogram was resolved to find the accurate peaks for redox reaction. Each peak indicates the formation of Tb-Bi intermetallic compound except Tb(III) reduction peak. From the phase diagram of Tb-Bi, it is inferred that each peak corresponds to TbBi2, TbBi, Tb4Bi3, and Tb5Bi3. The open circuit chronopotentiometry was conducted to estimate Gibbs free energy of formation of Tb-Bi intermetallic compound.
The experimental results obtained from three kind of the electrochemical techniques showed that Tb-Bi intermetallic compounds were electrochemically formed under potential of Tb(III) reduction potential by co-reduction of Bi(III) and Tb(III). These results indicate that underpotential deposition by co-reduction could be used for Tb(III) removal from the salt waste with Bi(III).
Experimental and Numerical Analysis of Steam Generator Tube Rupture Event for MYRRHA Reactor in CIRCE Facility With SIMMER-IV Code
Authors: Pesetti Alessio , Tarantino Mariano , Forgione Nicola 
Published: October 2018

The Steam Generator Tube Rupture (SGTR) postulated event constitutes one of the most hazardous safety issues for Gen IV pool reactors, cooled by heavy liquid metals. This accidental scenario is characterized by quick water flashing when in contact with primary coolant liquid metal, causing pressure wave propagation, cover gas pressurization in the reactor main vessel as well as possible tube rupture propagation, vapour dragged through the core, oxides precipitation and consequent slugs and plugs formation.
The design phase of Gen IV MYRRHA reactor addressed the SGTR scenario issues in the framework of MAXSIMA project, supported by the European Commission. This research activity was fully executed at ENEA CR Brasimone, where a new test section was designed, assembled, instrumented and implemented in the large scale pool facility CIRCE. It was supported by the execution of preliminary and detailed pre-tests analysis performed adopting SIMME-III and -IV code, respectively.
This paper details the test section main features, able to host four full scale portions (each one constituted by 31 tubes) of the MYRRHA Primary Heat eXchanger (PHX), for carrying out four independent SGTR experiments. A couple of tests investigated the tube rupture at middle position between two spacer grids of the bundle. The other two tests analysed instead the rupture near the bottom tube plate. Auxiliary systems were adopted for reaching primary (Lead Bismuth Eutectic alloy, LBE) and secondary (water) coolant initial conditions in accordance with MYRRHA design. Water was injected at 16 bar and 200°C in LBE at 350°C under an argon cover gas at about atmospheric pressure. The experimental results of the first test (middle rupture), in terms of CIRCE vessel pressurization, vapour flow path through tube bundle and tubes deformation, are presented.
The post-test analysis was performed by SIMMER-IV code adopting the 3D Cartesian code version. The whole main vessel of CIRCE facility and implemented test section were modelled conserving heights and flowing areas. The experimental initial conditions were successfully matched by numerical results as well as the vessel pressurization and temperature time trends in the tube bundle following the SGTR. An important engineering feedback, for MYRRHA designer, was the evidence of rupture propagation absence. Moreover, the effectiveness of implemented safety devices, rupture disks, was evaluated and characterized for pressure relief feedbacks.
A wide series of high quality measured data (pressure, temperature, strain and mass flow rate) was acquired and constitutes a database enlargement for future codes validation and possible new model development.
Application of Vorticity Method in Auxiliary Impeller Optimization of HTR-PM Main Helium Fan
Authors: Fei Mo , Youjie Zhang 
Published: October 2018

The helium circulator is an important part of HTR-PM. In order to avoid the heat which produced by the helium calculator of HTR-PM cumulating in the motor cavity, the heat should be taked out by the way of forced convection. According to the the spatial structure of channel, we need to design a single stage axial flow compressor here which has the technical characteristics with small power, small flow and high pressure. Let it meet the cooling demand of the specific heat of the motor, and also reduce the power consumption of cooling system itself, so as to improve the overall efficiency of the system.
To sum up, in the present study, through the design path of the positive problem, the conventional variable method is used to solve the flow field, that is, the flow field is solved by the velocity and pressure terms, and then the vortex in the flow field is deduced according to the velocity distribution According to the distribution of vorticity in the flow field, it provides the direction for the optimal design of the impeller. In the end, we hope to use this optimized design method to further optimize the blades and runner of the auxiliary impeller of helium circulator for HTR-PM.
Transient Analysis of Fire Protection System at a Nuclear Power Plant Using Computer Code USLAM
Authors: Arastu Asif H. , Tom Eugene 
Published: October 2018

A new Method Of Characteristics (MOC) based computer code, USLAM, has been used to analyze the Fire Protection System (FPS) of a Nuclear Power Plant. Some unique features of this system are that it has a complex geometry, has many operating modes, is connected to an adjacent nuclear power plant FPS, and has a significant number of high elevation standpipes or risers. In a typical FPS, firefighting water is pumped from a low elevation reservoir at atmospheric pressure to the whole system including higher elevations regions where water hammer due to water column separation & rejoining may occur. A low capacity keep-full system is employed to keep the system pressurized during standby conditions. A loss of system pressure due to the opening of the pre-action or deluge valves can lead to void formation at high elevations whose collapse can result in severe water hammer. A catastrophic valve failure due to a water hammer event at a nuclear power plant (Arastu, et al, 1999) disabled the entire FPS.
The analysis presented in this paper is to evaluate the possibility of such a water hammer event and mitigate it in an effective manner. The mitigation method employed is the use of multiple vacuum breakers. As many as 11 vacuum breakers are used for this purpose. The paper discusses the analysis results without and with vacuum breakers for all operating modes. The basic methodology of the USLAM code is also discussed.
Health-related quality of life in patients with uveitis
Authors: Shamdas Mohith , Bassilious Kerolos , Murray Philip Ian 
Published: October 2018

Background/aimsTo measure health-related quality of life (HRQOL) in patients with uveitis using time trade-off (TTO) and standard gamble (SG) methods of direct utility analysis.MethodsConsecutive patients attending a tertiary referral uveitis clinic were administered standardised, interview-delivered TTO and SG questionnaires and completed the European Quality of Life Five Dimensions Five Level (EQ5D-5L) questionnaire. Clinical data recorded included best-corrected visual acuity, uveitis anatomical and clinical classifications, duration since diagnosis, disease activity, current medication and any ocular or systemic comorbidities.ResultsTwo hundred patients with uveitis (124 female, 76 male, median age 54 years) were included. Overall mean TTO utility was 0.831 (95% CI 0.802 to 0.860); mean SG utility was 0.868 (95% CI 0.840 to 0.896) and mean EQ5D-5L utility was 0.742 (95% CI 0.702 to 0.782). There was a negative correlation between visual acuity and mean HRQOL (6/12 or better: TTO 0.86, SG 0.893; 6/15–6/60: TTO 0.662, SG 0.742; worse than 6/60: TTO 0.608, SG 0.712). Poor vision in the better- seeing eye (p=0.004), bilateral disease (p=0.047) and concurrent glaucomatous optic neuropathy (p=0.005) were predictors of poor TTO HRQOL. No correlation was found between HRQOL and duration of diagnosis, a flare of uveitis or being on systemic therapy. Patients with uveitis with poor vision have a TTO value worse than patients with end-stage renal failure on haemodialysis or those with AIDS.ConclusionLoss of vision resulting from uveitis is associated with reduced HRQOL. The TTO and SG utility values appear directly dependent on the degree of vision loss and not on the duration of disease or systemic medications.
Assessing the operational feasibility and acceptability of an inhalable formulation of oxytocin for improving community-based prevention of postpartum haemorrhage in Myanmar: a qualitative inquiry
Authors: Than Kyu Kyu , Oliver Victoria , Mohamed Yasmin , La Thazin , Lambert Pete , McIntosh Michelle , Luchters Stanley 
Published: October 2018

ObjectiveThis study assessed the potential operational feasibility and acceptability of a heat-stable, inhaled oxytocin (IOT) product for community-based prevention of postpartum haemorrhage in Myanmar.MethodsA qualitative inquiry was conducted between June 2015 and February 2016 through focus group discussions and in-depth interviews. Research was conducted in South Dagon township (urban setting) and in Ngape and Thanlyin townships (rural settings) in Myanmar. Eleven focus group discussions and 16 in-depth interviews were conducted with mothers, healthcare providers and other key informants. All audio recordings were transcribed verbatim in Myanmar language and were translated into English. Thematic content analysis was done using NVivo software.ResultsFuture introduction of an IOT product for community-based services was found to be acceptable among mothers and healthcare providers and would be feasible for use by lower cadres of healthcare providers, even in remote settings. Responses from healthcare providers and community members highlighted that midwives and volunteer auxiliary midwives would be key advocates for promoting community acceptance of the product. Healthcare providers perceived the ease of use and lack of dependence on cold storage as the main enablers for IOT compared with the current gold standard oxytocin injection. A single-use disposable device with clear pictorial instructions and a price that would be affordable by the poorest communities was suggested. Appropriate training was also said to be essential for the future induction of the product into community settings.ConclusionIn Myanmar, where home births are common, access to cold storage and skilled personnel who are able to deliver injectable oxytocin is limited. Among community members and healthcare providers, IOT was perceived to be an acceptable and feasible intervention for use by lower cadres of healthcare workers, and thus may be an alternative solution for the prevention of postpartum haemorrhage in community-based settings in the future.
Is the alcohol industry doing well by ‘doing good’? Findings from a content analysis of the alcohol industry’s actions to reduce harmful drinking
Authors: Babor Thomas F , Robaina Katherine , Brown Katherine , Noel Jonathan , Cremonte Mariana , Pantani Daniela , Peltzer Raquel I , Pinsky Ilana 
Published: October 2018

ObjectivesThe aims of this study were to: (1) describe alcohol industry corporate social responsibility (CSR) actions conducted across six global geographic regions; (2) identify the benefits accruing to the industry (‘doing well’); and (3) estimate the public health impact of the actions (‘doing good’).SettingActions from six global geographic regions.ParticipantsA web-based compendium of 3551 industry actions, representing the efforts of the alcohol industry to reduce harmful alcohol use, was issued in 2012. The compendium consisted of short descriptions of each action, plus other information about the sponsorship, content and evaluation of the activities. Public health professionals (n=19) rated a sample (n=1046) of the actions using a reliable content rating procedure.Outcome measuresWHO Global strategy target area, estimated population reach, risk of harm, advertising potential, policy impact potential and other aspects of the activity.ResultsThe industry actions were conducted disproportionately in regions with high-income countries (Europe and North America), with lower proportions in Latin America, Africa and Asia. Only 27% conformed to recommended WHO target areas for global action to reduce the harmful use of alcohol. The overwhelming majority (96.8%) of industry actions lacked scientific support (p<0.01) and 11.0% had the potential for doing harm. The benefits accruing to the industry (‘doing well’) included brand marketing and the use of CSR to manage risk and achieve strategic goals.ConclusionAlcohol industry CSR activities are unlikely to reduce harmful alcohol use but they do provide commercial strategic advantage while at the same time appearing to have a public health purpose.