Safety Upgrades Research Articles

Performance testing of roof beam–column connections for precast N-system

The precast N-system based on embedded-pin connections is used widely to construct large precast industrial halls in south-eastern Europe and further afield, including areas of high seismicity. To realistically assess the seismic performances, safety margins and limitations of the connections, experimental investigations are essential. Experimental results from laboratory tests on a large-scale prototype model of an original roof beam–column connection show its actual bearing capacity, damage propagation pattern and specific failure mode. The experimental study was then extended to a prototype model of an upgraded roof beam–column connection. To improve safety, the connection was upgraded with improved concrete confinement and stronger steel connecting pins. The experimental results show clearly that the method implemented to upgrade the pin-based connection provided very limited upgrading effects. To obtain much better and more reliable safety upgrading, an innovative and effective upgrading method had to be developed. The capability of the implemented refined nonlinear three-dimensional (3D) micro-modelling concept to realistically simulate the complex nonlinear response of the tested original and upgraded roof beam–column connections was demonstrated by an extensive analytical simulation study.

Dose Rate Assessment Around the PCFV Release Line During Severe Accident Conditions in Nuclear Power Plant Krsko

Abstract Passive containment filtered vent (PCFV) was installed in Nuclear Power Plant Krsko (NEK) in 2013 as part of the safety upgrade program. It is intended for severe accident consequences prevention and mitigation by ensuring the containment integrity. When the pressure in the containment reaches limiting value, containment atmosphere is released into the environment through the PCFV system exhaust line. But, before release in the environment, the containment atmosphere passes through five aerosol filters in the containment and one iodine filter in the auxiliary building (AB) to reduce isotopic activity. In this paper, dose rates around the exhaust line of the PCFV system resulting from radioactivity release in case of a severe accident were determined in a four-step methodology. The assumed severe accident scenario is a beyond design basis accident station blackout (SBO) in NEK, which was simulated using the MELCOR code. Its results were input for the radionuclide transport and removal and dose estimation (RADTRAD) radiological calculations to obtain the activities released in the containment. These activities were then transformed into the gamma source intensity and spectrum using the ORIGEN-S libraries. This form of the source term is required for Monte Carlo calculations which were performed using the MCNP6.2. Two Monte Carlo calculations were performed. One for which the radiation source was modeled to emanate from the containment atmosphere and the other from the PCFV duct fluid. The main reason for the calculation was to assess limiting dose rates around PCFV duct (radiation monitor location) during actuation after severe accident. That is why the model is simple and conservative. The other task was to demonstrate that this location is not suitable for longer personnel presence in case of equipment failure during the PCFV actuation. Due to conservative assumptions, predicted dose rates are the highest expected at that location for any severe accident scenario.

Evaluation of Safety Management of Smart Construction Sites from the Perspective of Resilience

In the context of green, low-carbon, and sustainable construction, the safety management of smart construction sites has been a key issue. Current related research mainly focuses on the application of technology, but lacks methods to evaluate the safety management level. Therefore, this research aims to construct a smart construction site safety management evaluation model from a resilience perspective. First, this research identified and screened the indicators initially based on the 4R resilience characteristics and 4M theory by analyzing the policy texts of smart construction site safety management. Then, through expert consultation, the ISM model of resilience indicators was established to determine the evaluation indicator system of smart construction site safety management. Next, the weight of each indicator was determined with the help of the analytic network process, and the evaluation criteria of the indicators were formulated according to the existing specifications and expert interviews; then, the evaluation model of smart construction site safety management was established. Finally, the feasibility of the model was proved through a case study. The findings of the research show that in terms of weights, management has the highest score, followed by media, man, and machine. However, more resilience measures are used for the safety management of machine than the other three in policy texts. Obviously, there is a deviation between weights and resilience characteristics. These findings help reveal the current situation of safety management at smart construction sites, which is of great significance for improving resilience. The findings also help smart construction sites to realize the upgrading of safety, efficiency, and greenness, and promote the sustainable development of smart construction sites as well as the construction industry.

Containerized Architecture Performance Analysis for IoT Framework Based on Enhanced Fire Prevention Case Study: Rwanda.

Nowadays, building infrastructures are pushed to become smarter in response to desires for the environmental comforts of living. Enhanced safety upgrades have begun taking advantage of new, evolving technologies. Normally, buildings are configured to respond to the safety concerns of the occupants. However, advanced Internet of Things (IoT) techniques, in combination with edge computing with lightweight virtualization technology, is being used to improve users’ comfort in their homes. It improves resource management and service isolation without affecting the deployment of heterogeneous hardware. In this research, a containerized architectural framework for support of multiple concurrent deployed IoT applications for smart buildings was proposed. The prototype developed used sensor networks as well as containerized microservices, centrally featuring the DevOps paradigm. The research proposed an occupant counting algorithm used to check occupants in and out. The proposed framework was tested in different academic buildings for data acquisition over three months. Different deployment architectures were tested to ensure the best cases based on efficiency and resource utilization. The acquired data was used for prediction purposes to aid occupant prediction for safety measures as considered by policymakers.

Dose Calculation for Emergency Control Room HVAC Filter

NPP Krsko is introducing Emergency Control Room (ECR) as part of safety upgrades. According to 10CFR50 Appendix A, GDC 19, both main control room and emergency control room should have adequate radiation protection to permit operators to shutdown the plant and keep it in safe shutdown conditions without receiving more than 50 mSv effective whole body dose, within 30 days from accident initiation. One of the important prerequisites to achieve that is proper operation of control room HVAC. In this work we are focused to calculation of gamma doses from radioactive materials accumulated in HEPA and charcoal filters during 30 days of HVAC operation. The dose at selected points around the filter was calculated using Microshield 10.0 point kernel code. The radioactive gamma source is calculated using RADTRAD 3.03 for plant's severe accident SGTR sequence calculated with MAAP 4.0.7 code. Calculated dose rates at peak filter activity are compared against results obtained with SCALE 6.2 MAVRIC shielding sequence (Monaco Monte Carlo functional module and CADIS methodology). The reasonable agreement between point kernel and hybrid Monte Carlo results was obtained.

NPP Krško Station Blackout Analysis after Safety Upgrade Using MELCOR Code

The analysis of a Station blackout (SBO) accident in the NPP Krško including thermalhydraulic behaviour of the primary system and the containment, as well as the simulation of the core degradation process, release of molten materials and production of hydrogen and other incondensable gases will be presented in the paper. The calculation model includes the latest plant safety upgrade with addition of Passive Autocatalytic Recombiners (PAR) and the Passive Containment Filter Venting (PCFV) system. The code used is MELCOR, version 1.8.6. MELCOR is an integral severe accident code which means that it can simulate both the primary reactor system, including the core, and the containment. The code is being developed at Sandia National Laboratories for the U.S. Nuclear Regulatory Commission. The analysis is conducted in two steps. First, the steady state calculation is performed in order to confirm the applicability of the plant model and to obtain correct initial conditions for the accident analysis. The second step is the calculation of the SBO accident with the leakage of the coolant through the damaged reactor coolant pump seals. Without any active safety systems, the reactor pressure vessel will fail after few hours. The mass and energy releases from the primary system cause the containment pressurization and rise of the temperature. The newly added safety systems, PAR and PCFV, prevent the damage of the containment building by keeping the thermalhydraulic conditions below the design limits. The analysis results confirm the capability of the safety systems to effectively control the containment conditions. Results of the analysis are given with respect to the results of the MAAP 4.0.7 analysis for the same accident scenario. The MAAP and MELCOR codes are the most popular severe accident codes and, therefore, it is reasonable to compare their results. In addition, sensitivity calculations performed by varying most influential parameters, such as the hot leg creep failure, blockage of a pipe connecting the cavity and the sump, inclusion of a radionuclide package in the MELCOR, etc. are done in order to demonstrate correct physical behaviour and the accuracy of the developed NPP Krško MELCOR model.

Evaluation of Impact of NEK Safety Upgrade Program Implementation on the Reduction of Total Core Damage Frequency

The nuclear accident in Japanese plants in 2011 has initiated a quick response from the countries utilizing a nuclear power. Krsko Nuclear Power Plant (NEK) was required by Slovenian Nuclear Safety Administration (SNSA) to perform consequential actions to reduce the risk of severe accidents and their consequences as low as feasible. NEK have analyzed the response to the severe accidents, and based on the results of this analysis, proposed the measures to be implemented in the shortest possible time. In response to SNSA request NEK has developed the Safety Upgrade Program (SUP) which contains a comprehensive set of measures for plant safety improvements. SUP Phase 1 has been implemented during the Outage 2013. This paper presents the work done on the evaluation of impact of plant modifications planned for implementation in Phases 2 and 3 of NEK Safety Upgrade Program on the quantitative figure of merit for the plant risk significance – total core damage frequency (CDF). A significance of the most valuable measures in terms of contribution to the CDF reduction was determined and a new fractional contribution of initiators categories was obtained. The quantification of total CDF was made by employment of RiskSpectrum PSA code and running a predefined set of analytical cases for all initiator categories covered by the scope of NEK PSA model. The basis for analysis was NEK’s most recent at-power PSA model which reflects the plant status with plant modernization implemented in SUP Phase 1. The analysis was done in two steps. In the first step plant modifications planned for SUP Phase 2 were addressed and in the second step plant modernization measures and upgrades planned in SUP Phase 3 were modeled in addition to those already modelled in the first step.

Novel “Rubber” electrolyte will be applied to long-lasting, safer future EV batteries

Solid-state lithium metal batteries (LMBs) have become a potential component, as they provide a considerable safety upgrade by eliminating flammable organic solvents. Solid polymer electrolytes (SPEs) are also a promising candidate, owing to their non-toxicity, low-manufacturing cost, and comparatively soft nature that allows the development of a seamless interface with the electrodes. Polymerization-induced phase separation (PIPS) controls the connectivity of phase-separated structures and domain size, enabling the co-continuous nanostructures’ formation. Researchers of a study published in Nature envisioned that outstanding mechanical and ionic properties could be realized, provided ionic conducting materials form a 3D interconnected phase inside a mechanically strong elastomer matrix via PIPS.

Safety Upgrades in Domestic Dwellings. Pluggable Off-Line UPSs of Low Quality and Backfeed Hazards

International policies incentive the reduction of energy consumptions in domestic dwellings and the use of energy from renewable sources, but do not sufficiently support their safety. Many domestic dwellings in many countries operate with the supplying neutral grounded (T) and with all the exposed conductive parts isolated (I) that is with a “TI-system.” This article deals with a concise presentation of these unclassified types of grounding systems and, then, with the backfeed hazard originated by pluggable off-line UPSs very commons in homes of stressed electrical grids. Against frequent blackouts, the users install battery powered automatic switchover type standby off line UPS. UPSs of low quality are unsafe and must be upgraded. Cases of back feed have been noted into utility supply lines from these UPSs and linemen doing maintenance by switching off supply receiving fatal shocks. This article examines the reasons for such back feed and gives few methods to eliminate fatal and often unforeseen back feed. It briefly discusses the needs of upgrading TI-system to TT-system, basic for the safety protection against touch voltages in domestic dwellings. It concludes expecting in a next time the promotion of the global grounding system as constitution of a public “grounding service” organized and managed similarly to the water, gas, energy, telephone, or internet services.

Smart Frontal Safety System for Automobiles

The focus of this work is to develop a new safety system in addition to reduce accidents for innocents in automobiles. When confronted with an accident, the only safety measure which we bet our lives on is “airbags”. In several cases, airbags alone may not be able to completely protect the passengers in the vehicle due to the high magnitude of the impact. In the present work, a new safety upgrade will be modeled in vehicles to absorb the sudden frontal impacts while in motion. The ultrasonic sensors are placed in the front portion of the vehicle which is set to propagate and receive ultrasonic waves while moving. The change of distance from the sensor to the obstacle is monitored continuously and in the event of an emergency, the frontal safety system in the vehicle gets activated. In such an event, the bumper or a metallic formed plate is actuated forward to a certain distance and upon striking the obstacle, the impact force is then reduced by shock absorbers or springs provided in the safety system. Hence, the impact transmitted to the passengers inside the vehicle is less when compared to the direct impact.

Unlocking solid-state conversion batteries reinforced by hierarchical microsphere stacked polymer electrolyte

Pursuing all-solid-state lithium metal batteries with dual upgrading of safety and energy density is of great significance. However, searching compatible solid electrolyte and reversible conversion cathode is still a big challenge. The phase transformation at cathode and Li deformation at anode would usually deactivate the electrode–electrolyte interfaces. Herein, we propose an all-solid-state Li-FeF3 conversion battery reinforced by hierarchical microsphere stacked polymer electrolyte for the first time. This g-C3N4 stuffed polyethylene oxide (PEO)-based electrolyte is lightweight due to the absence of metal element doping, and it enables the spatial confinement and dissolution suppression of conversion products at soft cathode-polymer interface, as well as Li dendrite inhibition at filler-reinforced anode-polymer interface. Two-dimensional (2D)-nanosheet-built porous g-C3N4 as three-dimensional (3D) textured filler can strongly cross-link with PEO matrix and LiTFSI (TFSI: bistrifluoromethanesulfonimide) anion, leading to a more conductive and salt-dissociated interface and therefore improved conductivity (2.5 × 10–4 S/cm at 60 °C) and Li+ transference number (0.69). The compact stacking of highly regular robust microspheres in polymer electrolyte enables a successful stabilization and smoothening of Li metal with ultra-long plating/striping cycling for at least 10,000 h. The corresponding Li/LiFePO4 solid cells can endure an extremely high rate of 12 C. All-solid-state Li/FeF3 cells show highly stabilized capacity as high as 300 mAh/g even after 200 cycles and of ~200 mAh/g at extremely high rate of 5 C, as well as ultra-long cycling for at least 1200 cycles at 1 C. High pseudocapacitance contribution (>55%) and diffusion coefficient (as high as 10–12 cm2/s) are responsible for this high-rate fluoride conversion. This result provides a promising solution to conversion-type Li metal batteries of high energy and safety beyond Li-S batteries, which are difficult to realize true “all-solid-state” due to the indispensable step of polysulfide solid–liquid conversion.

Citizen Scientist: Frank von Hippel’s Adventures in Nuclear Arms Control PART 8. Nuclear-reactor Safety Again

ABSTRACT The Fukushima accident of 2011 pulled von Hippel back into the reactor-safety world. He was invited to join a Congressionally-mandated four-year study of the lessons that could be learned from the Fukushima accident to improve the safety of US nuclear plants. During that study he learned more about both a much worse accident that almost happened at Fukushima, and about how the US Nuclear Regulatory Commission had come to use “risk-informed regulation” as a way to avoid requiring costly safety upgrades opposed by US nuclear utilities. He campaigned unsuccessfully at both the national and state levels to move the nuclear utilities away from densely packed spent fuel pools by moving fuel that had cooled for more than five years to dry-cask storage. He also promoted on-site dry-cask storage in Japan and South Korea as an alternative to reprocessing. This last chapter ends with some stories of his father, also a physicist, who would not be intimidated and who was a leader in the development of the field of materials science and engineering.

Retracted: Effect of driving domain on driving attitude profiles in winter seasons of India

AbstractThe trademark of motor vehicle use and driving attitude profiles explores new safety upgrades and energy redemption because of the role of driving attitude profiles and driving domains on road mishaps and traffic intensities. Thus, the goal of this research was to identify driving attitude profiles for multiple driving domains (on the basis of speed limits and winter conditions) from real‐world driving information and to investigate how these driving environments have an impact on driving attitude profiles. The study for this research was located in Bhubaneswar, India, where driving information from 64 motorists was collected with Fog Monitor (FM‐120) for at least 12 months. The outcomes indicate that both speed limits and winter states influence driving attitude profiles significantly. Specifically, for winter states, the outcomes provide authentication that motorists drive more quietly (normal speed is 21% lower for zero visibility (visibility < 100 m) than under haze conditions (visibility: 2–5 km), while positive and negative accelerations decrease by 7% and 9%, respectively), when deliberating the effect of speed limit more local streets (limits II, III, and IV streets) are the ones that present more reckless driving profiles in terms of acceleration (30%–40% increase from limit I to limit IV streets). The contribution of this study regards the quantification of the impacts of driving domains on driving attitude profiles, providing evidence that winter conditions significantly affect driving attitude profiles, leading motorists to adjust their driving attitude profiles to the driving domains. However, regarding the speed limit, the differences found in driving attitude profiles seem to be more a consequence of the infrastructure characteristics than an adjustment of driving attitude profiles.

Innovative approaches to the formation of environmental safety at the objects of oil and gas production

The innovative approach to environmental safety upgrade of pumping-circulatory equipment of drilling rigs based on the analysis of life history and continuous perfection principles. Examples of implementation of innovative approach in environmental safety investigation of oil and gas wells in order to define environmentally hazardous units of equipment and technological processes are given. In order to solve the problem of environmental safety improvement and the effectiveness of flushing out of well that are being drilled a modernized scheme of drilling rig pumping-circulatory system has been designed. System approach of modernizing separate elements of pumping-circulatory system has been used. The maximum air-tight pumping-circulatory drilling rig system has been designed. The proposed model takes into account the necessity of hazardous evaporations outlet with the aim of their further utilization. Such an approach will avoid the entry harmful substances into the environment and prevent harmful effects of aggressive substances on health personnel of drilling rig, environment and on state of the technological equipment.

Multi-hazard visual inspection for defining safety upgrading strategies of learning facilities at territorial level: VISUS methodology

School safety is one of the main concerns of administrators and decision-makers both for saving lives and for guaranteeing the continuity of education. This is especially true in natural hazard-prone areas, but it is also true for human-induced hazards. The elaboration and implementation of action plans for reducing the risk level of schools require both assessing all the relevant hazards potentially affecting each school and considering the resources available for the realisation of the required safety upgrading interventions. This paper illustrates the multi-hazard VISUS methodology adopted by UNESCO within the Comprehensive School Safety framework, in line with the Sendai framework for disaster risk reduction 2015–2030. VISUS was conceived and developed to provide decision-makers with a quick assessment of safety situations, upgrading needs, and status conditions of a large set of existing learning facilities. The methodology is the result of progressive improvements derived from multiple applications in pilot projects worldwide and in international peer reviews. This paper aims to illustrate the VISUS methodology, framing it within scientific literature. It also presents a selection of outcomes, describing the graphical indicators designed for supporting decision-makers in developing school safety upgrading strategies. Then, an overview of the VISUS applications shows improvements and evolutions of the methodology over the years and recaps its main specificities, highlighting how it can contribute to supporting the implementation of school safety initiatives.

Relative doses instead of relative concentrations for the determination of the consequences of the radiological atmospheric releases

Radiological atmospheric releases require population dose calculation for proper determination of preventive measures. The old concept of relative concentrations requires long lasting constant emission which is not realistic.The proposed concept of the “relative doses” is the generalization and expansion of the known concept of relative concentrations. Relative doses allow an evaluation of the general non-stationary pollutants emission under the real weather conditions over complex terrain. Relative doses can be calculated even before the actual source term – quantified emission - is known.The relative impact is also very useful for considering the possible impact of an accident scenario on the surroundings for various meteorological situations. This is applied for environmental impact assessments which require long term statistical evaluation. The method has a practical possible application for realistic dose assessment of effectiveness of additional protection achieved by installation of Passive Containment Filtered Venting Systems (PCFVS). PCFVS is considered an obligatory safety upgrade after the Fukushima accident.

The evaluation of the in vitro antimicrobial properties of fibers functionalized by chitosan nanoparticles

In this work, chitosan (CS) and its water-soluble derivatives, N,N,N-trimethyl chitosans (TMC), were used in the form of solution and nanoparticles dispersions (CSNP) as an adsorbate for cellulose fibers in order to obtain bioactive functionality of fibers aimed toward use in tampons. To examine the usability of bioactive tampons it is extremely important to provide detailed information about tampons’ antimicrobial capacity regarding pathogen microorganisms (MOs), as well as for those responsible for healthy flora such as Lactobacillus sp. Thus, evaluation of the in vitro antimicrobial properties of functionalized fibers was performed in detail using the standard shake-flask test method (ASTM E2149) and “time-kill” method (non-standard method) against S. aureus, E. coli, and C. albicans. Both methods were compared. Susceptibility of Lactobacillus sp. to coated fibers was tested as well. Additionally, cytotoxic properties of fibers were evaluated as a further indicator of safety aspect of tampons functionalized by CS and TMC. The results show that specific functionalization of tampons using CS nanoparticles could improve tampon antimicrobial activity and offer a safety upgrade for the regular feminine cotton tampon, providing an attractive feature.

The Improvement of an APEX Machine involved in the Tire Manufacturing Process

Over the years, there has been a huge expansion in the automotive component industry and its consequent innovation, which has evolved along with automation and robotics. Therefore, in order to ensure component quality, as well as the quality of the entire production process, it is crucial to enhance competitiveness in the sector. Since quality is a key feature in this industry, all manufacturers and suppliers are scrutinized by systematic audits to ensure constant improvements. This work was developed at a multinational industry and focuses on tire production for the automotive sector. Tires present a complex production process, which covers a wide range of activities from mixing, preparation, construction and vulcanization to the inspection departments, all of which are greatly predisposed to process improvement. In one of these departments (Preparation - APEX machines, responsible for the tire bead production), one of the main problems detected was directly related to a large number of failures in the pneumatic systems. These were found to be difficult to control, both in terms of speed and positioning. Some of the failures in automation were generating delays in certain processes, leading to lengthy setup times and culminating in higher production costs. In order to achieve greater quality, reliability and accuracy, a higher level of automation was applied to these kinds of machines by resorting to 5S methodology. A safety upgrade of the equipment was also undertaken, which will allow for the improvement of workplace safety.The performance improvement of the APEX machines was reached by implementing the following strategies: the automation of conveyor and tray movements between the cutting and application subprocesses; the implementation of 5S methodology; the automation of the cutting process; the updating of safety devices; and the automated control of the separation subprocess. A strong decrease in the breakdown time was recorded (-62%) resulting of the project implementation. The APEXmachine performance was also improved in 9%.

Trading service quality for safety: a cautionary tale from the French ‘Robien law’ on elevator safety

To deal with elevator accidents the French ‘Robien law’ mandated safety upgrades for ‘old’ elevators. Available statistics suggest that the law reduced fatal accidents but also coincides with an unprecedented deterioration in service quality, multiplying breakdowns and downtime. We exploit a unique data set of more than 3500 elevators over 10 years to investigate the law’s impact. Using a difference-in-difference setting, our results indicate that the law led to a considerable increase in the number of failures and downtime. We also find evidence that the situation was exacerbated by the fact that the higher failure rates were not met by a sufficient increase in maintenance staff.

Switchgear operating personnel safety upgrade solutions for aged installed base

The study presents novel solutions and risk mitigation strategies to reduce internal arc and accidental electrical contact injuries hazard and health consequences. Motorised closed-door racking in–out operational mode enables to modernise the installed base equipment and to keep personnel at a safe distance: by an innovative hard-bus retrofill design concept, enabling to install a standard motorised-racking withdrawable new breaker into a wide range of existing panels, or by adding on existing panels an external motorisation system applicable to roll-in retrofit. Both solutions improve operational procedure safety on installed base, keeping personnel out of arc flash boundaries and reducing personal protection equipment requirements.