Preliminary Engineering Study Research Articles

DEM Simulation of the Idaho Calcine Simulant for Hot Isostatic Pressing Canister Filling Process: Part 2

This paper introduces a novel approach to the bulk material handling of simulated radioactive material, focusing on the challenging Idaho calcine waste. Due to the limited availability of the simulant, virtual dynamic simulations were utilized to develop technology demonstration−scale models to assess the efficacy of the discrete element method (DEM) for process development studies. The DEM model was validated using historical experimental data, demonstrating its feasibility with affordable hardware. Acknowledging the limitations of computational analysis, the presented contact model is deemed adequate for preliminary engineering studies. This research advances bulk material handling and provides valuable insights for nuclear waste treatment processes, offering a pioneering framework for researchers working with the Idaho calcine simulant.

Discrete Element Method Simulation of the Idaho Calcine Simulant for Hot Isostatic Pressing Canister-Filling Process: Part 1

In preliminary engineering studies and equipment commissioning, readily available simulants with certain resemblances to the target waste, such as particle size, may be employed. However, for the validation of engineering processes, it is crucial to use simulants that closely replicate the physical and flow characteristics of the waste material, typically excluding radioactivity. The production of such simulants can entail significant costs. To facilitate the development of novel engineering solutions, the U.S. Department of Energy provided a nonradioactive alumina calcine simulant. This simulant was utilized to demonstrate a hot isostatic press (HIP) canister-filling system designed by Gravitas Technologies in Australia. The simulant was synthesized through a fluidized-bed calcination process, which mirrored the chemistry and procedure employed for the actual alumina Idaho calcine waste material. Consequently, the simulant exhibited physical properties akin to the actual calcine, including particle size distribution, bulk density, and flow properties. This first paper, Part 1, presents the powder characterization test results determined by a Freeman FT-4 rheometer and the calibration methods that determined a set of unique contact model parameters for dynamically simulating Idaho calcine simulant in a discrete element method (DEM) model. The second paper, Part 2, will present the dynamic simulations of two bulk material-handling scenarios in a full-scale, three-dimensional integrated HIP canister-filling system. The predicted results are compared with historical experimental results for validating the contact model. The contact model, which represents the particle-particle and particle-boundary interactions, was calibrated according to experimental data obtained from six calibration tests. This work aims to support future research with powder characterization experimental data and a calibrated DEM contact model to assist in developing processes for the safe handling and treatment of Idaho calcine waste.

Applicability of two-dimensional numerical simulation associated with vortex-induced vibration response of the circular cylinder

ABSTRACT The VIV responses of the circular cylinder at low and moderate Reynolds numbers are calculated according to two-dimensional numerical simulation and the fourth-order Runge–Kutta algorithm. The first part of the study is focused on the applicability of 2D numerical simulation between the response of 2D numerical simulation and the actual response, which can guide the preliminary engineering studies by vortex shedding. The reasonable vortex shedding mode of each branch, and the change process of the trajectory from the ‘8’ type to the ‘droplet’ type, are discussed in the second part of the study. And independent calculations under different speed reduction conditions are employed to suit practical application scenarios. The comparison shows the applicability of the 2D numerical simulations at low Reynolds numbers. Although the amplitude calculation results at moderate Reynolds numbers are inconsistent with the experimental results, the two-dimensional numerical simulation has good reliability in the trailing vortex capture.

Determination Of Thermal Technical Characteristics Of Sewage Sludge

One of the largest environmental problems of the Russian Federation is the pollution of the territory waste. The focus is on waste generated during the treatment of urban wastewater - sewage sludge and sewage sludge (SS). The shortage of areas sharply raised the issue of eliminating these wastes. The main elimination method is high temperature combustion. The complex process of elimination requires preliminary heat engineering studies of sewage sludge. In the scientific work, gas-analytical studies of flue gases were carried out, the experimental process of preliminary drying of sewage sludge was reproduced, and calorimetric tests of specific samples of precipitation were calculated with recalculation to the lower calorific value.

Modeling and Assessment of Short-Term Electromagnetic Interference on a Railway System From Pole-to-Ground Faults on VSC-HVDC Cable Networks With Sea Electrodes

This work falls under the preliminary engineering studies that are carried out to assess the interference impact, which may be raised from the operation of the bipolar HVdc cable link between Attica and Crete. The interference impact concerns critical and public infrastructures that are located in close proximity to the intended link's on-shore routing. In this article, particular emphasis is given in modeling a specific interference situation, on a collocated railway system, that ascends from pole-to-ground fault conditions that may occur on the planned bipolar voltage source converter (VSC)-HVdc cable network. To this extent, the simulation analysis takes into account the specific characteristics of the interfering VSC-HVdc technology and the results are constructively benchmarked against the safety thresholds tabulated in international standards.

Preliminary forensic engineering study on aggravation of radioactive releases during the Fukushima Daiichi accident

Even after 6years since the Fukushima accident, the exact accident progression for each unit and location of core debris have not been clarified, although solidified low-melting metal debris was identified at the bottom of the 1F3 reactor pressure vessel (RPV) in July 2017. Currently efforts are directed towards robotic inspection with remote cameras, as well as dose and temperature measurements of the environment inside the Primary Containment Vessels (PCV). In spite of their effort, the observed environmental temperature distribution data does not support the existence of a significant radiation heat sources attributable to the molten core at the bottom of the PCV. At this point the total decay heat of the core debris should be as large asa few hundred kilowatts after 2000days since the initiation of the accident as summarized in Annex A. In addition, the temperature of the accumulated water inside PCVs is 10–20°C even with a reduction of the water injection to 3.0m3/h. The RPVs appear to be holding the heating core debris with water, implying that “in-vessel retention” of core debris has been achieved thanks to effective accident management. This should help greatly in the retrieval of the core debris by removing the top head of RPV.Under these circumstances the author has conducted a forensic engineering study (i.e., different fields of science working together to collect and integrate independent evidences) to clarify the most likely accident scenarios of the Fukushima Daiichi accident. Through this study the author identified that a large portion of the land contamination observed at the north-west direction is mostly the result of the accident that occurred at Unit 2.In this unit its blowout panel, provided for over-pressure protection against a main steam pipe breach in the secondary confinement building, was inadvertently activated before a leakage of radioactive effluent from the PCV. Its activation is believed due to the hydrogen explosion in Unit 1 which occurred on March 12, next day of the Fukushima accident initiation. By losing the confinement function, the radioactive effluent leaked from the 1F2’s PCV and would have been discharged without mitigation. This accident scenario explains the series of leakage events identified in two of the 24 monitoring posts which had been installed by the Fukushima Prefectural Government. A series of six large releases were repeated between March 15 and 16, behaving like a periodical actuation of the safety valves for the PCV. Such multiple release events were very likely induced by the overpressure release of the PCV due to leakage of the dry well flange. This leakage should have been induced through discharging steam and hydrogen due to the activation of Safety and Release Valves (SRV) into the suppression pool (SP) water. Unfortunately the wet well atmosphere must have been that of air, since there was no nitrogen charge line to the atmosphere of the SP surface water. The resultant air-hydrogen mixture resulted in an “internal hydrogen explosion” which should have deformed the flange. The recent robotic inspection inside PCV revealed that a gigantic water splash appears to have occurred at the bottom of the PVC dislodging the gratings installed over the platform.Next to the series of large releases from Unit 2, Unit 1 also induced two large releases on March 12. Fortunately, these releases left more than 3 orders of magnitude less soil contamination compared with the series of releases from Unit 2. Unit 3 also released a significant amount of radioactive species twice on March 13, resulting in a very small soil contamination. The main constituent of the radioactivity is likely radioactive noble gases in this unit.

Characteristic friction coefficient and scale effects in oscillatory porous flow

This work presents a simple method to evaluate the performance of a porous breakwater when it is impinged with normal incidence by a non-breaking monochromatic wave train. It is based on: 1) a potential flow model for wave interaction with permeable structures and 2) a set of experimental tests on a rectangular porous structure with uniform granular distribution. A characteristic friction diagram is obtained considering wave energy balance in a control volume, minimising the error between the numerical model and the experimental results for the wave transmission coefficient. Results show that, for large breakwater widths, the reflection process reaches a saturation regime before the waves exit the structure at a distance from the seaside between the interval 0.2 < x/ L < 0.45. For larger breakwater widths, the reflection coefficient is almost constant (except for “resonant” conditions) and wave transmission decreases exponentially. Under such conditions, the wave propagation through the porous medium depends on the relative diameter D/ L and the porosity of the material; the dependence on the relative breakwater width B/ L and the ratio diameter wave height D/ H is weak. This diagram intends to be useful for preliminary engineering studies of breakwater's efficiency and performance and as an adequate selection criteria of the experimental stone diameter to minimize scale effects in laboratory studies.

Modeling of Thermal Performance of a Cooling Tower Using an Artificial Neural Network

In the present study, the ability of an artificial neural network model to evaluate the thermal performance of a cooling tower, which used in the heating, ventilating, and air conditioning industries to reject heat to the atmosphere, is examined. The network is trained with the following experimental values: the ratio of the water mass flow rate to air mass flow rate, the inlet water temperature, and the outlet water temperature, and the inlet air wet-bulb temperature are selected as input variables, while the output is the coefficient of performance. It is concluded that a well-trained neural network provides fast, accurate, and consistent results, making it an easy-to use tool for preliminary engineering studies.

Planning for the First Light Rail Transit System in Korea: Jeonju Light Rail Transit Project

Pursuing a low-cost, yet modern, high-quality, medium-capacity transit system to improve their transit services, several Korean cities have opted for automated guided transit systems. Yet in 1999 the city of Jeonju decided to introduce a light rail transit (LRT) system not only to improve its transit services but also to improve living conditions, expand business activities, and increase livability. The initial study was performed in 1999, and the preliminary engineering study was completed in 2001. The project is now into the final design leading up to construction. The system consists of a network of two independent lines 24.92 km long with 46 stations and is planned to operate mainly on the street median with a separate right-of-way. The project will be financed and operated by the public sector according to the Public Investment Inducement Act. The first line is scheduled to open in 2008 and the second line in 2010. Numerous issues and elements should be considered for successful project implementation because Korea has no experience in building an LRT system. Although the project seems to be going well, opposition from local organizations has been encountered. The history of the Jeonju LRT system is presented. The system features are described, including network alignment, projected ridership, and financing. Major elements considered and issues encountered during the planning process are also discussed.

The concept of the volumetric neutron source on the basis of the JUST-T tokamak for minor actinides transmutation

By concept development of the compact volumetric neutron source on the spherical tokamak JUST basis for minor actinides transmutation with aspect ratio A = 2, some key plasma physics problems are arising: start of discharge; plasma current maintenance in stationary stage; appropriate neutron fluence for transmutation. On the basis of accepted physical and technical preconditions of the concept the combined scenario of current start and ramp-up, its stationary maintenance due to bootstrap effect and drive by neutral particle injection are considered. The plasma current is proposed to be initiated inductively and then bootstrap current will generate with using additional heating by injection of neutral beams. Necessary neutron flux for effective transmutation (Γn ≈ 0.4 MW/m2) will be reached by both plasma-beam reactions and thermal plasma fusion reactions. By the way of preliminary consideration engineering studies of vacuum chamber, toroidal magnetic system, divertor, and blanket with energy multiplicatio...

Short circuit currents of the SEPTA traction power distribution system

The Southeastern Pennsylvania Transportation Authority (SEPTA), USA, is undertaking a multi-phase modernization program of various electrical and infrastructure facilities. In this effort, a considerable amount of the facilities will be upgraded or replaced. The electrical power supply system is planned to be upgraded with modern state-of-the-art equipment. The overall aim of this effort is to increase the system performance and reliability while maintaining passenger and operator safety. In order to further the implementation of the ongoing modernization program, SEPTA authorized a preliminary engineering study of its electrical system. This effort included a comprehensive set of traction power system load flow studies, voltage drop analyses, short circuit studies, grounding grid analyses for the new substations and protective relay coordination studies. This article discusses the method developed to perform the short-circuit studies. The method is readily adaptable to many different feeder, trolley and track configurations.

Statistical and Simulation Analysis Assists Santa Clara Valley Water District Planning

Using Extend simulation software, we analyzed the Santa Clara County, California water supply. We determined that (1) the drought situation (1987–1992) can be expected to occur two or three times per 100 years, and (2) the supply will frequently not meet current annual demand and will fall far short of projected demand by 2020. We evaluated alternative courses of action. Using our analyses, the Santa Clara Valley Water District (1) negotiated a clause that saved $4 million on water contracts during 1992–1993, (2) evaluated using a storage facility in another California county, and (3) started preliminary engineering and environmental studies on a new reservoir.

Induced Draft Fan Innovation for Heat Recovery Steam Generators

A first of its kind, induced draft (ID) heat recovery steam generators (HRSG) have been in service at a cogeneration facility since 1991. A preliminary engineering study considered a forced draft (FD) fan to supply combustion air to the HRSG duct burners (when the combustion turbine (CT) is out of service) as a traditional design; however, the study indicated that the FD fan may require the HRSG duct burner to be shut off following a CT trip and re-ignited after the FD fan was in service. Although the induced draft HRSG design cost more than the FD fan design, the induced draft design has improved the cogeneration facility’s steam generation reliability by enabling the HRSG to remain in service following a CT trip. This paper briefly summarizes the preliminary engineering study that supported the decision to select the ID fan design. The paper also discusses the control system that operates the fresh-air louvers, duct burners, HRSG, and ID fan during a CT trip. Startup and operating experiences are presented that demonstrate the effectiveness of the design. Lessons learned are also summarized for input into future induced draft HRSG designs.

Annular Re-injection of Drilling Wastes

Summary Annular reinjection offers a cost-effective disposal mechanism for the oily cuttings and associated wastes generated when oil-based muds are used during drilling. This disposal method eliminates overboard cuttings discharge and hence removes any environmental impact. Continued use of oil-based muds is therefore feasible. A 12-member Drilling Engineering Assn. in Europe (DEAE) project was initiated in 1990 to study the engineering aspects of this approach in the North Sea. This paper reports on the first trial off a fixed platform in the North Sea and discusses the preliminary engineering studies, injection, and analysis of fracture propagation. It demonstrates that, with proper regard to the engineering of the injection well, the process is a safe, efficient, and effective disposal technique. Introduction Low-toxicity oil-based muds (LTOBM's), used widely in the North Sea operating area, offer significant operational benefits, especially for exploration and appraisal drilling and, more importantly, for development drilling. However, the overboard discharge of the oil-contaminated cuttings leads to environmental damage that, although localized, is unacceptable. To resolve this conundrum, novel water-based muds were evaluated and a range of cleaning and disposal options for the cuttings was reviewed. From these options, cuttings slurrying and reinjection appeared to offer the most cost-effective solution because this approach would also address the problem of oily liquids from the drilling unit. Cuttings slurrying and reinjection is established practice in Alaska and the Gulf of Mexico, but the technique had not been used previously in the North Sea. We knew that the legislative authorities would have some concerns. Therefore, 12 operating companies sponsored a joint project, through the auspices of the DEAE, to evaluate the engineering issues associated with this approach. The project was established with three objectives in mind:to demonstrate that cuttings slurrying and reinjection was technically viable for the North Sea,to gain acceptance of this approach to waste management from North Sea legislative authorities, andto evaluate a novel approach to cuttings grinding.

Central tracking with micro strip gas chambers in CMS

A central tracking detector based on micro strip gas chambers (MSGC) for the compact muon solenoid (CMS) at LHC is part of a hybrid inner tracking system to be operated in a 4 Tesla magnetic field. Expected performance in terms of momentum resolution, rate capability and long term survivability will be discussed. Considerable efforts in simulation studies have been made, to optimize the tracking system for pattern recognition and track finding efficiencies. A preliminary engineering study on mechanical stability and heat load shows that the detector structures can be made sufficiently stiff to maintain systematic alignment precision within the intrinsic spatial measurement accuracy of the detector.

Oil and Gas Developments in Eastern Canada in 1988

Exploration activity on Canada's east coast offshore region continued at a steady rate in 1988. A total of 10 wells were active: 1 exploratory well offshore Nova Scotia, and 5 exploratory wells and 4 delineation wells offshore Newfoundland. The highlights of 1988 were Mobil's discovery of a new gas and condensate pool south of Sable Island offshore Nova Scotia, and successful delineation drilling results offshore Newfoundland by Petro-Canada at Terra Nova and by Husky Oil Operations at Whiterose. Based on these successes, the estimates of discovered oil and gas resources for the region have been revised upwards to 235 million m3 (1.5 billion bbl) of oil and condensate and 309.4 billion m3 (10.9 tcf) of natural gas. A significant step was made toward development of the Hibernia oil and gas field with the signing of a Statement of Principles by the governments of Canada and of Newfoundland and Labrador with Mobil Oil Canada and its partners. Also Petro-Canada is undertaking a preliminary engineering study to evaluate alternative development scenarios for Terra Nova field. Studies are also in progress on possible schemes to develop the several natural gas discoveries and the 2 small oil discoveries in the Nova Scotia offshore. Legislation required to implement joint federal-provincial resource management offshore Nova Scotia has been passed by the Canadian Parliament and the provincial legislature and will likely be proclaimed in 1989. At that point, a new resource management board will assume responsibility for the Nova Scotia offshore. This arrangement is identical to that established in the Newfoundland offshore in 1987. The future looks bright for the East Coast given the stable resource management regime, the regular schedule of rights issuances, and the large remaining potential. Steps to development of the best of the discoveries will lead to an increase in the pace of exploration in the early 1990s. Activity in Ontario in 1988 was at its highest level since 1980, with drilling completed at a total of 188 wells for an aggregate length of nearly 107,000 m (350,000 ft). Activity was paced by a record amount of drilling of Ordovician targets, as interest in this very successful play continued to increase. Drilling of Ordovician targets was reported to be complete at 25 exploratory wells, 15 development wells, and 2 stratigraphic tests, resulting in 21 new oil producers and 4 gas producers. Oil production in Ontario increased dramatically in 1988, due entirely to production from new Ordovician reservoirs discovered since 1983. Production totaled approximately 190,570 m3 (1.2 million bbl) compared to 135,635 m3 (853,000 bbl) in 1987. Further production increases a e expected in 1989. Activity in Quebec in 1988 was concentrated in the Basse-Terres region near Trois Rivieres in the St. Lawrence lowlands, and on Anticosti Island. Five exploratory wells and 6 natural gas storage wells were drilled. Two of the exploratory wells resulted in discovery of an accumulation of natural gas in unconsolidated glacial sediments beneath Lake St. Pierre on the St. Lawrence River. There was no drilling activity in onshore portions of Prince Edward Island, Nova Scotia, New Brunswick, or Newfoundland in 1988.

Telescope Technology For The Far Ultraviolet Spectroscopic Explorer (FUSE)

Preliminary engineering studies are in progress to define a telescope for the Far Ultraviolet Spectroscopic Explorer (FUSE) mission. General science objectives include high resolution spectroscopy in the 900 A to 1200A spectral region, low or moderate resolution spectroscopy in the 100 A to 900 A range, and long slit imaging over a 1 arcmin field at a spatial resolution of 1 arcsec. Telescope design studies indicate that a 1 m diameter Wolter-Schwarzschild type II glancing incidence telescope with an effective collecting area of 3000 cm2 is required to meet the primary science objectives. A baseline optical design has been completed and initial alignment sensitivities derived to begin the process of error allocation for the entire system. Various mirror fabrication methods are being evaluated, including the incorporation of contemporary diamond turning technology with computer-controlled polishing.

Rail and road traffic continue during bridge modification

The crossing of Route 15 under the Bangor and Aroostook Railroad Bridge, Bangor, Maine had limited sight distance and marginal clearances. Maine Department of Transportation, therefore, proposed to reconstruct Route 15 at the crossing to improve horizontal and vertical alignment. A preliminary engineering study recommended modifying a portion of the bridge abutment to have Route 15 pass with an acceptable alignment. This included removal and reconstruction of the north abutment wingwall without any disruption to rail traffic. This was accomplished by constructing the new wing in two parts. The far end part was built first. The coffer dam to retain railroad embankment spanned between this part and the existing abutment. Excavation in front of the coffer dam was then completed and the remainder of the wing wall was constructed.

Intra-CBD Secondary Travel Patterns of Downtown Workers

Previous Downtown People Mover (DPM) feasibility studies have shown that the majority of the average daily DPM trips will be made by downtown workers during their travel to and from the downtown (Primary Travel) and within the downtown (Secondary Travel). An understanding of the travel patterns of downtown workers has become a prerequisite in developing alignments and in maximizing patronage of DPMs. A preliminary engineering study for the Detroit (Michigan) DPM, an alternatives analysis study for a distribution and circulation system in downtown Atlanta (Georgia) and a feasibility study for a Norfolk (Virginia) DPM form the basis for this paper. These projects were performed for the Southeastern Michigan Transportation Authority, Georgia Department of Transportation and the City of Norfolk respectively. During these studies, questionnaire surveys were conducted to understand the existing travel patterns of downtown workers and to calibrate DPM patronage forecasting models. The intra-CBD secondary travel patterns obtained from the surveys of CBD workers in these three cities are discussed.

Critique on Design of Pipeline Crossings

Pipeline crossings of natural barriers such as streams can involve many engineering problems. There are several hazards involved in buried stream crossings, especially those that have a moving stream bed material. There are potential and real dangers involved when excavations are made in a riverbed downstream from a buried pipeline crossing or any type of highway bridge structure. Pipeline bridge structures can be classified as cable suspension, combination pipeline-highway, deck bridge, and pipe trestle. The design of pipelines attached to highway bridges must give due consideration to live-load deflections. Pile trestles in general can be built at a very reasonable cost. In locations where pile trestle type of structures cannot be utilized, the use of a cable suspension span or a highway type of bridge structure can be built. However, these types of structures represent higher construction costs. Preliminary engineering studies must be included as part of the selection process before determining the type of crossing to be built.