Fuel Inventory Research Articles

Serpent-2 and OSCAR-4 computational tools compared against McMaster nuclear reactor improved operational data history for U-235 fuel inventory tracking, local power tracking and validation of multiplication factor

The tracking of fuel inventory is important for safety and for knowledge of the flux distribution. In a research reactor, tracking of the reactor core fuel composition using simulation code is crucial for fuel management strategy, such as by optimizing the core pattern for sample irradiation purposes and for providing an economical fuel cycle length. Operational data history for the McMaster Nuclear Reactor (MNR) is a valuable asset for comparing and validating simulation code. A previous study examined U-235 content using the nodal diffusion code Overall System for CAlculation of Reactors (OSCAR-4) against standard MNR operational data and recommended considering the Pu-239 content in the energy production in the standard operational data. In this work, a new method was implemented by introducing a Fuel Inventory Correction (FIC) factor for improving the U-235 operational data records. U-238 and Pu-239 code-to-code tracking comparisons were also employed. The maximum difference between U-235 at end of life (EOL) and the updated operational data history was 2.43% and 6.97% for Serpent 2 and OSCAR-4, respectively. The FA power profile tracking showed a similar response whenever fuel shuffling and/or refueling occurred, with a maximum different of 16% (30 kW) in one cycle. The multiplication factors for the two sets of code differed systematically, averaging 0.9982 and 1.0051 for Serpent 2 and OSCAR-4, respectively.

Fuel inventory and material migration of JET main chamber plasma facing components compared over three operational periods

Fuel retention and material migration results from JET ITER-like wall beryllium limiter tiles are presented for three operating periods. Ion beam analysis results support the general picture of erosion during limiter configurations with local deposition on tile ends far into the scrape off layer. Similar trends of fuel concentrations are observed in all JET operating periods; (i) low on surfaces exposed to high heat flux and erosion and (ii) higher in deposits. The pattern of fuel retention and deposition correlates with heat flux and distribution of limiter plasmas touching inner and outer limiters. The D/Be ratio in the thickest deposit is ∼0.01. Global fuel retention attributed to limiters is <0.01% of injected fuel. Marker coatings reveal a rapid transition from strong erosion to deposition within 15 mm. This work highlights the need to carefully consider the requirements of marker coatings for long exposure studies in high erosion areas.

Fuel inventory and impurity deposition in castellated tungsten tiles in KSTAR: experiment and modelling

Plasma-facing components have castellated structure for thermo-mechanical durability and integrity under high heat flux loads. However, fuel co-deposition in the grooves of the castellation may enhance fuel retention. In KSTAR, castellated tungsten tiles were tested to investigate the impact of tile shaping and misalignment on the retention. The tiles with poloidal and toroidal gaps of 0.5 mm were exposed at the divertor during a whole campaign encompassing 4364 s of plasma operation. Surfaces inside the gaps were analysed by means of 3He-based micro-NRA, ERDA and PIXE. Modelling of carbon deposition was performed with the impurity transport code 3D-GAPS assuming impurity penetration along the magnetic field lines with plasma-wetted areas defined by simple geometrical shadowing. The main deposited element is carbon with different concentration at the entrance of the groove, dependent on the tile shaping: 6 × 1017 cm−2 for a chamfered and misaligned gap and up to 283 × 1017 cm−2 for a flat and aligned gap. The deposition patterns are exponentially decreased to 4–10 × 1016 cm−2 inside the gap. Deuterium concentration in the gaps described above ranges, respectively, from 2 × 1017 cm−2 to 50 × 1017 cm−2 at the top of the groove and decreases to 1–4 × 1016 cm−2 following the carbon deposition trends. The highest carbon and deuterium densities are measured at the plasma-exposed side of the flat tile and aligned gap. Modelled deposition profiles reproduce qualitatively the experimentally observed trends.

Emission inventory of alternative fuels for a turboprop engine considering flight conditions

The aviation sector continues to work in many directions to limit the impact of global climate change on the struggle. In this context, it has achieved significant gains especially with the improvements in motor technologies. However, in order to achieve the desired targets, not only technological but also alternative studies based on alternative fuels have taken the agenda. In this context, fossil fuel improvements also developed as an important field of study. This study primarily evaluated the thermodynamic analysis of alternative fuel-based preferences for a turboprop engine. Then, environmental effects, which are defined as CO2 emissions, caused by entropy production due to irreversibility were investigated. Especially the benefits of alternative fuel preferences were defined by their CO2 emission potentials. At the end of the study, the effects of alternative fuel use with engine performances were evaluated.

Emission inventory of alternative fuels for a turboprop engine considering flight conditions

The aviation sector continues to work in many directions to limit the impact of global climate change on the struggle. In this context, it has achieved significant gains especially with the improvements in motor technologies. However, in order to achieve the desired targets, not only technological but also alternative studies based on alternative fuels have taken the agenda. In this context, fossil fuel improvements also developed as an important field of study. This study primarily evaluated the thermodynamic analysis of alternative fuel-based preferences for a turboprop engine. Then, environmental effects, which are defined as CO2 emissions, caused by entropy production due to irreversibility were investigated. Especially the benefits of alternative fuel preferences were defined by their CO2 emission potentials. At the end of the study, the effects of alternative fuel use with engine performances were evaluated.

QUESTIONS THAT ARE ARRANGED WHEN CARRYING OUT THE EXAMINATION ON DOCUMENTAL CONFIRMATION OF THE FAILURE OF COMBUSTIBLE MATERIALS.

One of the most important tasks of economic expertise in the study of accounting, tax accounting and reporting documents, which are established by the Scientific and Methodological Recommendations on the preparation and appointment of forensic examinations and expert studies, approved by order of the Ministry of Justice of Ukraine of October 8, 1998 № 53/5, is the definition of a documentary confirmation of the size of the shortage of fixed assets, material values, stocks, including the shortage of fuel and lubricants.&#x0D; The above regulatory document to the indicative list of issues addressed by this type of forensic examination included the following:&#x0D; - Is the shortage of fixed assets, material values, stocks (including fuel and lubricants) established by the inventory report at the enterprise (the name of the enterprise is indicated) documented for the period of the materially responsible person (the employee is indicated, the materially responsible person) in the amount of (indicate quantitative and value indicators) as of (date indicated)?&#x0D; In the modern world, business entities for conducting accounting and tax accounting, the preparation of documents using specialized software.&#x0D; Therefore, recently, a significant part of forensic economic examinations on the issue of confirming the shortage of fixed assets, material values, stocks, including fuel and lubricants, is appointed not only for properly prepared inventory materials and accounting records of a business entity provided for research to experts, but also by screenshots (snapshots of images on the screen of documents, programs, diagrams, etc.), which in their opinion may be documentary evidence of this s accounting and inventory results.&#x0D; The article describes an example of the question put to the study, provides an analysis of the current legislation of Ukraine on the correctness of the inventory of fuels and lubricants and the determination of the shortage, as well as an algorithm for conducting expert examinations as defined by the legislation of Ukraine. Analyzed the materials provided to the expert, which cannot be documented evidence of a shortage of fuel and lubricants.

Monte Carlo fuel burnup analyses of the Accelerator-Driven Subcritical systems

This paper describes the Monte Carlo fuel burnup analysis performed for the Argonne National Laboratory (ANL) Accelerator-Driven Subcritical (ADS) conceptual design. The ANL ADS conceptual design was developed to dispose of the 131 tons of Minor Actinides (MA) fuel of the current United States Spent Nuclear Fuel (SNF) inventory. It uses a neutron source from 1 GeV 25 MW proton beam with the liquid lead target to drive the subcritical fission assembly. It utilizes the liquid metal slurry fuel concept to load the MAs fuel. The subcritical fission assembly has a neutron multiplication factor of 0.98. The total fission power generated in the system is about 2.67 GW. The system is designed to operate for 35 full power years. Monte Carlo fuel burnup analyses were performed to calculate the amount of MAs consumed by the ANL ADS conceptual design. The MCNP6 computer program was used to simulate the high energy physics of the protons striking the liquid lead target for generating the neutron source. The MCB5 and SERPENT Monte Carlo burnup computer programs were used to simulate the fuel burnup during the ADS operation. In the ANL ADS conceptual configuration, the reactivity loss during the fuel burnup is compensated by adding fresh fuel into the subcritical assembly. In this paper, both batch and continuous fueling modes are examined. The fresh fuel particles are loaded into the slurry fuel carrier at the beginning of each burnup step of the batch-fueling mode and loaded continuously into the slurry fuel carrier during the operation in the continuous fueling mode. Monte Carlo fuel burnup analyses show that one ANL ADS conceptual design can consume about 25.7 tons of MAs fuel during the 35 full power years with the continuous fueling mode. About five units is required to dispose of the 131 tons of MAs.

Fuel inventory and deposition in castellated structures in JET-ILW

Since 2011 the JET tokamak has been operated with a metal ITER-like wall (JET-ILW) including castellated beryllium limiters and lamellae-type bulk tungsten tiles in the divertor. This has allowed for a large scale test of castellated plasma-facing components (PFC). Procedures for sectioning the limiters into single blocks of castellation have been developed. This facilitated morphology studies of morphology of surfaces inside the grooves for limiters after experimental campaigns 2011–2012 and 2013–2014. The deposition in the 0.4–0.5 mm wide grooves of the castellation is ‘shallow’. It reaches 1–2 mm into the 12 mm deep gap. Deuterium concentrations are small (mostly below 1 × 1018 cm−2). The estimated total amount of deuterium in all the castellated limiters does not exceed the inventory of the plasma-facing surfaces (PFS) of the limiters. There are only traces of Ni, Cr and Fe deposited in the castellation gaps. The same applies to the carbon content. Also low deposition of D, Be and C has been measured on the sides of the bulk tungsten lamellae pieces. Modelling clearly reflects: (a) a sharp decrease in the measured deposition profiles and(b) an increase in deposition with the gap width. Both experimental and modelling data give a strong indication and information to ITER that narrow gaps in the castellated PFC are essential. X-ray diffraction on PFS has clearly shown two distinct composition patterns: Be with an admixture of Be–W intermetallic compounds (e.g. Be22W) in the deposition zone, whilst only pure Be has been detected in the erosion zone. The lack of compound formation in the erosion zone indicates that no distinct changes in the thermo-mechanical properties of the Be PFC might be expected.

Fuel Inventory of the Multi-Bed Storage System of the SDS Considering Daily Operation of the Tokamak

A Tokamak has startup and shutdown periods during which demand specifications differ from those during steady fueling operation. These periods can affect the required number of getter beds of the Storage and Delivery System. In this study, we developed a mathematical model based on the State Task Network, and an algorithm that considers daily operation which includes the period from startup to shutdown to find the optimal number of getter beds. This algorithm can estimate the optimal initial inventory of tritium or deuterium in a getter bed to compensate for fuel consumption until shutdown. The inductive operation mode of the Tokamak is analyzed to illustrate the applicability of the model and algorithm.

Fuel inventory and price relationships in the U.S. electric power sector under regulatory and market change

Long-run relationships among coal inventories at U.S. electric power plants, corporate bond rates and coal, natural gas, and electricity prices are estimated over the period July 1976 to October 2014. Tests for constancy of the long-run relationships show periods of instability which coincide with major regulatory events in the electric power sector. Deregulation of the natural gas and electricity markets are likely sources of instability for the period mid-1994 to mid-2001. Additionally, inventory behavior may have had a smoothing effect over instability caused by natural gas prices during the recent U.S. shale boom. Policy makers should be aware that altering the regulatory environment can result in considerable fluctuations in how firms’ inventory decisions interact with input and output markets and opportunity costs in the long run.

PENGARUH POROSITAS PACKING STEEL WOOL TERHADAP PRESSURE DROP DIDALAM PACKED BED COLUMN PADA DISTILASI CAMPURAN ETANOL-AMIL-ALKOHOL-AIR

Inventories of petroleum fuels are increasingly depleted and will someday run out. These shortcomings can be overcome by using alternative fuels, such as ethanol. Based on this, it is necessary to research and development of ethanol as a fuel. One way is with a separation in a packed distillation column. This study aims to assess the mass transfer phenomena that occur in the process of distilling a mixture of ethanol-water-amyl alcohol packed in column. In addition, this study aims to optimize temperature and reflux to obtain the highest levels of ethanol. This research method uses packed bed distillation system with the batch process. Feed used is synthetic ethanol, water, and solvent. Solvent used were amyl alcohol. Doing distillation with heating temperature is maintained. Distillation is done in the packing of stainless steel wool. Research carried out in a batch process with a variable temperature of 79°C; 84°C; 91°C; and porosity packing 20%; 30%; 40%; 50%; 60%; 70%; 80%.

Uncertainty Propagation of Fission Product Yield Data in Spent Fuel Inventory Calculations

The effects of correlations between uncertainties of independent yields are considered to propose a method of including covariance terms within uncertainty propagation for spent fuel inventory calculations and a method outlined to achieve this. The use of the “Total Monte-Carlo” technique for such calculations are investigated for a simple decay example and for the case of a fission pulse calculation and the results discussed.

Uncertainty in Life Cycle Greenhouse Gas Emissions from United States Coal

Coal is an abundant energy resource, consumed in the United States chiefly by the power generation sector. Due to potential energy security benefits, it has also been considered as an alternate source for gasoline and diesel production. Life cycle assessment (LCA) studies have previously estimated the greenhouse gas emissions associated with coal combustion as well as upstream activities such as mining and transport, to compare its environmental impact with other fuels. Until recent years, LCA studies predominantly ignored the uncertainty and variability inherent in life cycle assessment. More recent work has estimated the uncertainty in the life cycle inventories of fossil fuels, but the use of these uncertainty ranges to model system-wide impacts has been limited. As shown by previous studies, uncertainty often affects the conclusions of comparative life cycle assessments, especially when differences in average environmental impacts between two competing fuels/products are small. This study builds upon ...

Quantifying Variability in Life Cycle Greenhouse Gas Inventories of Alternative Middle Distillate Transportation Fuels

The presence of variability in life cycle analysis (LCA) is inherent due to both inexact LCA procedures and variation of numerical inputs. Variability in LCA needs to be clearly distinguished from uncertainty. This paper uses specific examples from the production of diesel and jet fuels from 14 different feedstocks to demonstrate general trends in the types and magnitudes of variability present in life cycle greenhouse gas (LC-GHG) inventories of middle distillate fuels. Sources of variability have been categorized as pathway specific, coproduct usage and allocation, and land use change. The results of this research demonstrate that subjective choices such as coproduct usage and allocation methodology can be more important sources of variability in the LC-GHG inventory of a fuel option than the process and energy use of fuel production. Through the application of a consistent analysis methodology across all fuel options, the influence of these subjective biases is minimized, and the LC-GHG inventories for each feedstock-to-fuel option can be effectively compared and discussed. By considering the types and magnitudes of variability across multiple fuel pathways, it is evident that LCA results should be presented as a range instead of a point value. The policy implications of this are discussed.

A line intersect distance sampling strategy for downed wood inventory

Perpendicular distance sampling (PDS) has emerged as a compelling alternative to line intersect sampling (LIS) for the inventory of forest fuels and other downed woody materials (DWM), particularly where the aggregate volume of DWM is of primary interest. This article develops a selection protocol and design-unbiased estimators for a new probability proportional-to-volume sampling strategy, termed line intersect distance sampling (LIDS). LIDS combines the distance sampling protocol of PDS with the transect sampling protocol of LIS and provides unbiased estimates of aggregate DWM volume from counts of selected logs or log fragments. Simulations indicate that LIDS along multidirectional (e.g., Y-shaped) transects should perform similarly to PDS in terms of sampling error; however, it remains unclear how LIDS and PDS compare with LIS, especially when interest is attached to multiple DWM population parameters. It is argued that LIDS will be most useful in reducing implementation errors, particularly detection errors, relative to PDS under limited visibility field conditions.

Determination of fission products in nuclear samples by capillary electrophoresis-inductively coupled plasma mass spectrometry (CE-ICP-MS)

Determination of fission products and of their isotopic composition is of high importance for the characterisation and complete inventory of nuclear fuels. Radiometric and mass spectrometric methods, which are currently used, enable only an incomplete determination of the fission products. Radiometric methods cannot be applied to all fission products and mass spectrometric methods are hindered by the existence of isobaric interferences, therefore a previous chemical separation is required before mass spectrometric analysis. Capillary electrophoresis (CE) has been coupled with inductively coupled plasma mass spectrometry (both ICP-QMS and ICP-SFMS). Typical detection limits of 6 ng/mL and 4 pg/mL for caesium as well as 8 ng/mL and 7 pg/mL for lanthanides have been obtained by CE-ICP-QMS and CE-ICP-SFMS, respectively. In addition to these very low detection limits, the procedures present the advantages to be fast (6 min for caesium and 13 min for lanthanides, respectively), to require a low microliter range sample volume and a nanoliter range injection volume. The radiation dose for the personnel as well as the volume of nuclear liquid wastes generated during the measurements are consequently reduced. The procedures have been applied to nuclear samples from PUREX process and leachates from MOX fuels.

Measurement repeatability of a large-scale inventory of forest fuels

An efficient and accurate inventory of forest fuels at large scales is critical for assessment of forest fire hazards across landscapes. The Forest Inventory and Analysis (FIA) program of the USDA Forest Service conducts a national inventory of fuels along with blind remeasurement of a portion of inventory plots to monitor and improve data quality. The goal of this study was to evaluate the measurement repeatability/biases of FIA's national inventory of fuels and suggest opportunities for improving data quality and application of sampling protocols. Results indicated that more than half of the attributes did not attain the desired levels of repeatability and about one-third exhibited a non-zero measurement bias. However, the bias generally had little affect on plot-level estimates. A number of factors that contributed to these results were examined and a holistic approach that considers all aspects of inventory was suggested to improve measurement repeatability.

Forest Fuel Inventory in 5 and 9-Year-Old Acacia Mangium Plantations

This study was conducted to determine the fuel components on forest floor of two different age stands and to estimate the fuel loading of the various fuel components. This study was carried out at Bukit Tarek Forest Reserve, Hulu Selangor, Selangor Darul Ehsan, at two stand age of Acacia mangium of 5 and 9-year-old. Fuel components of downed woody material and duff were sampled along transects lines. Shrubs, litter, herbaceous and small trees ( 1 of total fuel (downed woody material, litter and herbaceous), 1.73 cm of duff depth, 37,030 stem haG 1 of shrubs density and 2,175 tree haG 1 of small trees. The 9 year-old stand showed 17.42 Mg haG 1 of forest fuel, 3.03 cm of duff depth, 39,151 stem haG 1 shrubs density and 3,515 tree haG 1 of small trees. Downed woody material made up of 89 and 74% of the total fuel weight for 5 year and 9-year-old stands, respectively. Comparison between two different age stands, showed that 5 year old stand has higher quantity of downed woody materials than 9 year-old stand with 20.66 and 12.82 Mg haG 1 , respectively. Based on diameter class interval, the weight of downed woody material, diameter class of 0-7.6 cm were higher compared to diameter class of >7.6 cm. The fuel weight for 0-7.6 cm diameter class was 12.48 and 9.94 Mg haG 1 for 5 and 9-year-old stands, respectively. Statistical analysis showed that the loading of downed woody material on 5-year-old stand was significantly greater than the 9 year-old stand. However, litter loading was greater on the 9-year-old stand than the 5-year-old stand. The study concludes that in terms of fuel loading, 5-year-old stand has higher fire risk than 9-year-old stand. This is due to the silviculture activities in the 5-year old stand

What Is the Fire Danger Now? Linking Fuel Inventories with Atmospheric Data

Abstract The combination of forest fuel maps with real-time atmospheric data may enable the creation of more dynamic and comprehensive assessments of fire danger. The goal of this study was to combine fuel maps, based on data from the Forest Inventory and Analysis (FIA) program of the USDA Forest Service, with real-time atmospheric data for the creation of a more dynamic index of fire danger. Results indicated fuel loadings and moisture could be estimated for specific points on a meteorological modeling grid network (4 × 4 km; based on FIA's strategic-scale fuel inventory and atmospheric data) enabling the current assessment and 1- to 2-day prediction of fire danger as well as refined understanding of fire danger across forest ecosystems.

Fuel Inventory and Co-Deposition in Grooves and Gaps of Divertor and Limiter Structures

Plasma facing components from JET and TEXTOR were studied. The emphasis was on the comparison of co-deposition, material mixing and fuel inventory on plasma facing and side surfaces of tiles, i.e. in gaps separating the tiles. Integrated fuel content in gaps of the Mk-I JET divertor floor was approximately two times greater than detected on the plasma facing surfaces. Taking into account similarities between the Mk-I structure and the castellation in the ITER divertor, the impact of the tile shaping on the tritium inventory is addressed. Deposition on the side of limiter tiles in TEXTOR was around 3–5% of that on the plasma facing surfaces. Experiments aiming at a deeper insight into the deposition on ITER-relevant components are also proposed.