I2S-LWR Top-Down Differential Economics Evaluation Approach

The Integral Inherently Safe Light Water Reactor (I2S–LWR) is a design concept of a large (~1000 MWe) light water reactor with integral primary circuit configuration. One of the key design features promoting inherent safety is implementation of an integral primary circuit configuration, which in turn requires a compact design of the core and primary circuit components. Assessments of the cost of I2S-LWR is an important aspect of the overall evaluation of the new reactor concept. There are several approaches to cost estimation and economics evaluation of the new nuclear power technologies. Frequently used guidelines rely on the Code of Accounts, originally developed in the U.S. Department of Energy (DOE) Energy Economics Data Base (EEDB) Program Code of Accounts, proposed as evaluation tool by C.R. Hudson, and further popularized in the guidelines for economic evaluation of bids, by The International Atomic Energy Agency (IAEA). The code of accounts allows to break down main costs (Total Capital Investment Cost, Fuel Cycle Cost, Operation and Maintenance) to individual systems and items. This work aims to implement and apply a top-down differential economics evaluation approach to the Code of Accounts based guidelines, to assess the costs of the I2S -LWR relative to a representative “standard” PWR. In this methodology, a representative PWR design was taken as a reference and the differential cost was estimated for each individual account based on the design difference (or similarity). Cost estimating techniques were applied to the accounts representing systems that differ from the ones of the reference PWR. In this manner, the cost of the common components cancels out, and the uncertainty in the estimate is reduced. While this preliminary evaluation yet needs to be completed, the indications so far are that the I2S-LWR LCOE will be economically competitive with a standard PWR

Cost optimization in agribusiness based on life cycle costing

In efforts to achieve and sustain competitiveness and contribute to the goal of sustainable development of society, entity management requires information that will enable the adoption of adequate decisions. The changed business environment and the growing importance of the issues that emerge from the domain of traditional business, both spatial and temporal, have necessitated the monitoring of costs not only during the production phase, but throughout the entire grain cycle of the product. Since conventional cost accounting systems do not have the capacity to generate the above information, in theory and practice, a life cycle costing system (LCC) has been developed. The aim of the paper is to point out the specificity and importance of perceiving and capturing the impacts and consequential costs that arise during the life cycle of the product, with particular reference to agribusiness, precisely because of the complexity of optimizing costs in that sector

Mineralni trioksidni agregat u terapiji eksterne resorpcije korena izbijenog zuba sa nezavršenim rastom korena - ishod posle deset godina

Introduction Root resorption may occur as a consequence of avulsion injury and may lead to the progressive loss of tooth structure. The aim was to report the outcome of root resorption treated with mineral trioxide aggregate in a replanted immature permanent incisor after 10 years of follow-up. Case outline This case presents external root resorption that was detected 18 months after the avulsion injury in a nine-year-old child. Apical portion of the canal was filled with mineral trioxide aggregate and the rest of the canal was filled with a canal sealer and gutta-percha. Control examinations were performed six months after the completion of the endodontic treatment and afterwards yearly. The tooth was asymptomatic clinically and radiographs did not show progression of root resorption up to four years of follow-up. Infraposition of the injured tooth was detected five years after the replantation, but without significant radiographic changes, until the eight-year follow-up, when root resorption was detected again. However, the tooth was still hard and symptomless at the 10-year follow-up. Conclusion Mineral trioxide aggregate may have an important role in the preservation of replanted immature teeth for a prolonged period.Uvod Resorpcija korena zuba se može javiti kao posledica povrede i može voditi progresivnom gubitku zubnih struktura. Cilj rada je bio da se prikaže klinički ishod replantacije izbijenog stalnog zuba sa nezavršenim rastom korena posle deset godina. Prikaz bolesnika Predstavljen je slučaj eksterne resorpcije korena zuba detektovane 18 meseci posle avulzione povrede kod devetogodišnjeg deteta. Apikalni deo kanala korena zuba je napunjen mineralnim trioksidnim agregatom, dok je ostatak kanala opturiran pastom i gutaperka poenima. Kontrolni pregledi su obavljani šest meseci posle završetka endodontskog lečenja i, posle toga, jednom godišnje. Do četvrte godine praćenja zub je bio bez kliničkih i radiografskih znakova progresije resorpcije korena. Infrapozicija povređenog zuba uočena je pet godina posle replantacije, ali bez značajnih radiografskih promena sve do osme godine praćenja, kada je uočeno napredovanje resorpcije korena. Ipak, posle deset godina zub je i dalje bio klinički bez simptoma. Zaključak Mineralni trioksidni agregat može imati značajnu ulogu u dugotrajnom očuvanju replantiranih zuba sa nezavršenim rastom korena

Integration of process planning, scheduling, and mobile robot navigation based on triz and multi-agent methodology

U radu je predstavljena metodologija za razvoj softverske aplikacije za integraciju projektovanja tehnološkog procesa, terminiranja proizvodnje i navigacije mobilnog robota u tehnološkom okruženju. Predložena metodologija je bazirana na primeni teorije inventivnog rešavanja problema i multiagentske metodologije. Matrica kontradikcije i inventivni principi su se pokazali kao efektivan alat za otklanjanje kontradiktornosti u koncepcijskoj fazi razvoja softvera. Predložena multiagentska arhitektura sadrži šest agenata: agent za delove, agent za mašine, agent za optimizaciju, agent za planiranje putanje, agent za mašinsko učenje i agent mobilni robot. Svi agenti zajedno učestvuju u optimizaciji tehnološkog procesa, optimizaciji planova terminiranja, generisanju optimalnih putanja koje mobilni robot prati i klasifikaciji objekata u tehnološkom okruženju. Eksperimentalni rezultati pokazuju da se razvijeni softver može koristiti za predloženu integraciju, a sve u cilju poboljšanja performansi inteligentnih tehnoloških sistema.This paper presents methodology for development of software application for integration of process planning, scheduling, and the mobile robot navigation in manufacturing environment. Proposed methodology is based on the Russian Theory of Inventive Problem Solving (TRIZ) and multiagent system (MAS). Contradiction matrix and inventive principles are proved as effective TRIZ tool to solve contradictions during conceptual phase of software development. The proposed MAS architecture consists of six intelligent agents: job agent, machine agent, optimization agent, path planning agent, machine learning agent and mobile robot agent. All agents work together to perform process plans optimization, schedule plans optimization, optimal path that mobile robot follows and classification of objects in a manufacturing environment. Experimental results show that developed software can be used for proposed integration in order to improve performance of intelligent manufacturing systems

Liquid-salt-cooled Reactor Start-up with Natural Circulation

The Liquid-Salt-Cooled Very High-Temperature Reactor (LS-VHTR) was modeled using the neutronics analysis code SCALE6.0 and the thermal-hydraulics and kinetics modeling code RELAP5-3D with objective to devise, analyze, and evaluate the feasibility and stability of a start-up procedure for this reactor using natural circulation of the coolant and under the Loss Of Offsite Power (LOOP) conditions. This Generation IV reactor design has been initially developed by Oak Ridge National Laboratory and studied by researchers worldwide for almost a decade. While neutronics and thermal-hydraulics analyses have been previously performed to show the performance of the reactor during normal operation and for shutdown scenarios, no study has heretofore been published to examine the active or passive start-up of the reactor. The fuel temperature (Doppler) and coolant density coefficient of reactivity of the LSVHTR were examined using the CSAS6 module of the SCALE6.0 code. Negative Doppler and coolant density feedback coefficients were calculated. Two initial RELAP5 simulations were performed to obtain the steady-state conditions of the model and to predict the changes of the thermal-hydraulic parameters during the shutdown of the reactor. Next, a series of step reactivity additions to the core were simulated to determine how much reactivity can be inserted without jeopardizing the safety and stability of the core. Finally, a start-up procedure was developed, and the restart of the reactor with natural convection of the coolant was simulated. The results of the simulations demonstrated the potential for natural circulation start-up of the LS-VHTR

Metodologija pregleda i ocena stanja konstrukcije izložbenih hala Beogradskog sajma

Beogradski sajam predstavlja jedno od najuspelijih ostva-renja domaće arhitekture i građevinskog konstrukterstva. Sagrađen je između 1954. i 1957. godine, prema arhitek-tonsko-urbanističkom rešenju Milorada Pantovića i kon-struktivnim rešenjima Branka Žeželja i Milana Krstića, kao moderno oblikovani kompleks sa tri izložbene hale prepoz-natljivih kupola. Hala 1 je najveći objekat kompleksa i zašti-ćena je kao spomenik kulture. Svojim specifičnim rešenjem predstavlja izuzetno konstruktivno ostvarenje, a njena kupola i danas drži Ginisov rekord za ovu vrstu konstrukcije. Insti-tut IMS redovno prati stanje objekata Beogradskog sajma i kroz stručnu podršku obezbeđuje sigurnu i funkcionalnu eks-ploataciju izložbenih hala. U radu su prikazani metodolo-gija i rezultati pregleda i ocene stanja konstrukcije Hale 1 nakon skoro 70 godina upotrebe, uključujući sprovedeno ispitivanje sile prednaprezanja u žicama kablova prstenas-tog nosača kupole Hale 1

Nuclear and thermal hydraulic calculation of a representative I2S-LWR first core

The Integral Inherently Safe Light Water Reactor (I2S-LWR) concept developed by Georgia Tech is a novel PWR reactor delivering electric power of 1000 MWe while implementing inherent safety features typical for Generation III+ small modular reactors. The main safety feature is based on integral primary circuit configuration, bringing together compact design of the reactor core (121 fuel assembly), control rod drive mechanism (CRDM), 8 primary heat exchangers (PHE), 4 passive decay heat removal systems (DHRS), 8 pumps, and other integral components. A high power density core based on silicide fuel and APMT (FeCrAl) stainless steel cladding is selected to achieve a high thermal power. Initial representative first core nuclear design is proposed by Westinghouse. Full core 3D depletion calculation was performed using PARCS code. The cross section library is prepared using FA2D code and verified using Polaris sequence from SCALE 6.2 beta5. The axial and radial reflectors are assumed to be homogeneous water-APMT mixtures. The axial reflectors are both assumed to be 12 inch (30.48 cm) sections composed of 30% APMT steel by volume. The radial reflector is assumed to be 90% APMT steel by volume. The reflector constants were calculated using SCALE TRITON sequence. The thermal hydraulic part of the model is based on COBRA subchannel code coupled to PARCS code. Initial depletion calculation is based on one thermal hydraulics channel per fuel assembly approach. The hot fuel assembly is determined using separate pin-by-pin COBRA subchannel model and pin power reconstruction data from PARCS. The objective of the paper is demonstration of LWR design methodology applicability to silicide fuel and identification of possible improvements in the first core design

PCA Benchmark Analysis with ADVANTG3.0.1. and MCNP6.1.1b Codes

The Pool Critical Assembly Pressure Vessel (PCA) benchmark is a well known benchmark in the reactor shielding community which is described in the Shielding Integral Benchmark Archive and Database (SINBAD). It is based on the experiments performed at the PCA facility in the Oak Ridge National Laboratory (ORNL) and it can be used for the qualification of the pressure vessel fluence calculational methodology. The measured quantities to be compared against the calculated values are the equivalent fission fluxes at several experimental access tubes (A1 to A8) in front, behind, and inside the pressure-vessel wall simulator. This benchmark is particularly suitable to test the capabilities of the shielding calculational methodology and cross-section libraries to predict invessel flux gradients because only a few approximations are necessary in the overall analysis. This benchmark was analyzed using a modern hybrid stochastic-deterministic shielding methodology with ADVANTG3.0.1 and MCNP6.1.1b codes. ADVANTG3.0.1 is an automated tool for generating variance reduction (VR) parameters for Monte Carlo (MC) calculations with MCNP5v1.60 code (and higher versions). It is based on the multigroup, discrete ordinates solver Denovo, used for approximating the forward-adjoint transport fluxes to construct VR parameters for the final MC simulation. The VR parameters in form of the weight windows and the source biasing cards can be directly used with unmodified MCNP input. The underlining CADIS methodology in Denovo code was initially developed for biasing local MC results, such as point detector or a limited region detector. The FW-CADIS extension was developed for biasing MC results globally over a mesh tallies or multiple point/region detectors. Both CADIS and FW-CADIS are based on the concept of the neutron importance function, which is a solution of the adjoint Boltzmann transport equation. The equivalent fission fluxes calculated with MCNP are based on several highenergy threshold reactions from international dosimetry libraries IRDF-2002 and IRDFF-2014, distributed by the IAEA Nuclear Data Section. The obtained results show a good agreement with referenced PCA measurements. Visualization of the deterministic solution in 3D was done using the VisIt code from the Lawrence Livermore National Laboratory (LLNL)

Challenges in experimental evaluation of morphological, chemo-mechanical and adhesive properties of glass-ionomer based dental materials

Changes in composition and new material characteristics require verification in clinical and experimental studies. Investigating glass-ionomer cements under laboratory conditions encounters problems in interpreting the results and in comparing them with other types of materials tested in the same way. As the connection between the glass-ionomer cements and the dental tissues is delicate, it is often the case that the impact of fractures and other artifacts is either underestimated or over-dimensioned when interpreting the results. A critical review was performed, with defining the main problems regarding the usage of SEM, EDX and nanoindentation techniques in glass-ionomer based materials evaluation