scholarly journals The Impact of Isotopic Composition of Lead on the Neutron-Physical Characteristics of Fast Reactor with Liquid Metal Coolant

2018 ◽  
Vol 3 (3) ◽  
pp. 400
Author(s):  
M.M. Ivanova ◽  
V.V. Kolesov ◽  
V.V. Korobeinikov ◽  
A.M. Terehova ◽  
G.L. Khorasanov
Keyword(s):  
Isotopic Composition ◽  
Fast Reactor ◽  
Reactor Core ◽  
Physical Characteristics ◽  
Reactor Model ◽  
Decay Products ◽  
Fast Reactor Neutron ◽  
Heterogeneous Models ◽  
The Impact ◽  
Effective Multiplication

It is well known, that lead coolant, highly enriched by 208Pb, has some advantages over other coolants. It is predicted that the use of 208Pb in the reactor core will lead to an increase in the production of plutonium and transmutation of long-lived decay products. The main objective of this paper was to investigate the influence of the isotopic composition on the fast reactor neutron-physical characteristics. For this purpose we used the RBETS-M benchmark - a fast energy reactor that includes 12 zones with different sizes and temperatures of the materials. Calculations were performed for homogeneous and heterogeneous models. Our calculations show that the replacement of the coolant with the natural lead to 208Pb and 208Pb together with Bi can substantially improve the neutron-physical characteristics of the fast reactor, in particular by reducing the initial reactivity margin. Studies of the heterogeneity effect in the reactor model showed an increase in the effective multiplication factor of about 1.5% at the end of the campaign.

scholarly journals Evaluation of isotopic composition of fast reactor core in closed nuclear fuel cycle

2017 ◽  
Vol 153 ◽  
pp. 07031
Author(s):  
Georgy Tikhomirov ◽  
Mikhail Ternovykh ◽  
Ivan Saldikov ◽  
Peter Fomichenko ◽  
Alexander Gerasimov
Keyword(s):  
Isotopic Composition ◽  
Nuclear Fuel ◽  
Fast Reactor ◽  
Fuel Cycle ◽  
Reactor Core ◽  
Nuclear Fuel Cycle ◽  
Closed Nuclear Fuel Cycle

Advances in the analysis of fast reactor core and coolant circuit structures

1992 ◽  
Vol 134 (1) ◽  
pp. 37-58
Author(s):  
Y.W. Chang ◽  
D.T. Eggen ◽  
A. Imazu ◽  
M. Livolant
Keyword(s):  
Fast Reactor ◽  
Reactor Core ◽  
Coolant Circuit

scholarly journals Pb isotopes in the impact melt breccia 66095: Association with the Imbrium basin and the isotopic composition of lithologies at the Apollo 16 landing site

2017 ◽  
Vol 466 ◽  
pp. 608-616 ◽  
Author(s):  
Joshua F. Snape ◽  
Alexander A. Nemchin ◽  
Jeremy J. Bellucci ◽  
Martin J. Whitehouse
Keyword(s):  
Isotopic Composition ◽  
Landing Site ◽  
Pb Isotopes ◽  
Impact Melt ◽  
The Impact

Concept of hydride fuel target subassemblies in a fast reactor core for effective transmutation of MA

1998 ◽  
Vol 271-273 ◽  
pp. 530-533 ◽  
Author(s):  
M Yamawaki ◽  
H Suwarno ◽  
T Yamamoto ◽  
T Sanda ◽  
K Fujimura ◽  
...  
Keyword(s):  
Fast Reactor ◽  
Reactor Core

scholarly journals Biofilm carrier migration model describes reactor performance

2017 ◽  
Vol 75 (12) ◽  
pp. 2818-2828 ◽  
Author(s):  
Joshua P. Boltz ◽  
Bruce R. Johnson ◽  
Imre Takács ◽  
Glen T. Daigger ◽  
Eberhard Morgenroth ◽  
...  
Keyword(s):  
Plug Flow ◽  
Biofilm Reactor ◽  
Bulk Liquid ◽  
Reactor Performance ◽  
Reactor Model ◽  
Operational Conditions ◽  
Limit Model ◽  
Biofilm Model ◽  
Reactor Models ◽  
The Impact

The accuracy of a biofilm reactor model depends on the extent to which physical system conditions (particularly bulk-liquid hydrodynamics and their influence on biofilm dynamics) deviate from the ideal conditions upon which the model is based. It follows that an improved capacity to model a biofilm reactor does not necessarily rely on an improved biofilm model, but does rely on an improved mathematical description of the biofilm reactor and its components. Existing biofilm reactor models typically include a one-dimensional biofilm model, a process (biokinetic and stoichiometric) model, and a continuous flow stirred tank reactor (CFSTR) mass balance that [when organizing CFSTRs in series] creates a pseudo two-dimensional (2-D) model of bulk-liquid hydrodynamics approaching plug flow. In such a biofilm reactor model, the user-defined biofilm area is specified for each CFSTR; thereby, Xcarrier does not exit the boundaries of the CFSTR to which they are assigned or exchange boundaries with other CFSTRs in the series. The error introduced by this pseudo 2-D biofilm reactor modeling approach may adversely affect model results and limit model-user capacity to accurately calibrate a model. This paper presents a new sub-model that describes the migration of Xcarrier and associated biofilms, and evaluates the impact that Xcarrier migration and axial dispersion has on simulated system performance. Relevance of the new biofilm reactor model to engineering situations is discussed by applying it to known biofilm reactor types and operational conditions.

Calculation studies of coated particles performance in sodium-cooled fast reactor

Kerntechnik ◽  
2021 ◽  
Vol 86 (1) ◽  
pp. 45-49
Author(s):  
N. V. Maslov ◽  
E. I. Grishanin ◽  
P. N. Alekseev
Keyword(s):  
Fast Reactor ◽  
Reactor Core ◽  
Heat Removal ◽  
Design Solution ◽  
Fast Neutrons ◽  
Steel Shell ◽  
Primary Circuit ◽  
Coated Particles ◽  
The Core ◽  
Fuel Assemblies

Abstract This paper presents results of calculation studies of the viability of coated particles in the conditions of the reactor core on fast neutrons with sodium cooling, justifying the development of the concept of the reactor BN with microspherical fuel. Traditional rod fuel assemblies with pellet MOX fuel in the core of a fast sodium reactor are directly replaced by fuel assemblies with micro-spherical mixed (U,Pu)C-fuel. Due to the fact that the micro-spherical (U, Pu)C fuel has a developed heat removal surface and that the design solution for the fuel assembly with coated particles is horizontal cooling of the microspherical fuel, the core has additional possibilities of increasing inherent (passive) safety and improve the competitiveness of BN type of reactors. It is obvious from obtained results that the microspherical (U, Pu)C fuel is limited with the maximal burn-up depth of ∼11% of heavy atoms in conditions of the sodium-cooled fast reactor core at the conservative approach; it gives the possibility of reaching stated thermal-hydraulic and neutron-physical characteristics. Such a tolerant fuel makes it less likely that fission products will enter the primary circuit in case of accidents with loss of coolant and the introduction of positive reactivity, since the coating of microspherical fuel withstands higher temperatures than the steel shell of traditional rod-type fuel elements.

scholarly journals Comparison of the impacts of thermal pretreatment on waste activated sludge using aerobic and anaerobic digestion

2018 ◽  
Vol 78 (8) ◽  
pp. 1772-1781 ◽  
Author(s):  
Hyungjun (Brian) Jo ◽  
Wayne Parker ◽  
Peiman Kianmehr
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Oxygen Demand ◽  
Waste Activated Sludge ◽  
Thermal Pretreatment ◽  
Decay Products ◽  
Anaerobic Biodegradability ◽  
Pretreatment Conditions ◽  
The Impact ◽  
Aerobic And Anaerobic

Abstract A range of thermal pretreatment conditions were used to evaluate the impact of high pressure thermal hydrolysis on the biodegradability of waste activated sludge (WAS) under aerobic and anaerobic conditions. It was found that pretreatment did not increase the overall extent to which WAS could be aerobically biodegraded. Thermal pretreatment transformed the biodegradable fraction of WAS (XH) to readily biodegradable chemical oxygen demand (COD) (SB) (16.5–34.6%) and slowly biodegradable COD (XB) (45.8–63.6%). The impact of pretreatment temperature and duration on WAS COD fractionation did not follow a consistent pattern as changes in COD solubilization did not correspond to the observed generation of SB through pretreatment. The pretreated WAS (PWAS) COD fractionations determined from aerobic respirometry were employed in anaerobic modeling and it was concluded that the aerobic and anaerobic biodegradability of PWAS differed. It was found that thermal pretreatment resulted in as much as 50% of the endogenous decay products becoming biodegradable in anaerobic digestion. Overall, it was concluded that the COD fractionation that was developed based upon the aerobic respirometry was valid. However, it was necessary to implement a first-order decay process that reflected changes in the anaerobic biodegradability of the endogenous products through pretreatment.

scholarly journals The Impact of the Physical Environment on Intrapartum Maternity Care: Identification of Eight Crucial Building Spaces

2019 ◽  
Vol 12 (4) ◽  
pp. 67-98
Author(s):  
Nicoletta Setola ◽  
Eletta Naldi ◽  
Grazia Giulia Cocina ◽  
Liv Bodil Eide ◽  
Laura Iannuzzi ◽  
...  
Keyword(s):  
Maternity Care ◽  
Physical Environment ◽  
Architectural Design ◽  
Well Being ◽  
Physical Characteristics ◽  
Interdisciplinary Studies ◽  
Room Size ◽  
Direct And Indirect Impacts ◽  
Indirect Impacts ◽  
The Impact

Objectives, Purpose, or Aim: This article investigates whether the physical environment in which childbirth occurs impacts the intrapartum intervention rates and how this might happen. The study explores the spatial physical characteristics that can support the design of spaces to promote the health and well-being of women, their supporters, and maternity care professionals. Background: Medical interventions during childbirth have consequences for the health of women and babies in the immediate and long term. The increase in interventions is multifactorial and may be influenced by the model of care adopted, the relationships between caregivers and the organizational culture, which is made up of many factors, including the built environment. In the field of birth architecture research, there is a gap in the description of the physical characteristics of birth environments that impact users’ health. Method: A scoping review on the topic was performed to understand the direct and indirect impacts of the physical environment on birth intervention rates. Results and Discussion: The findings are organized into three tables reporting the influence that the physical characteristics of a space might have on people’s behaviors, experiences, practices and birth health outcomes. Eight building spaces that require further investigation and research were highlighted: unit layout configuration, midwives’ hub/desk, social room, birth philosophy vectors, configuration of the birth room, size and shape of the birth room, filter, and sensory elements. Conclusions: The findings show the importance of considering the physical environment in maternity care and that further interdisciplinary studies focused on architectural design are needed to enrich the knowledge and evidence on this topic and to develop accurate recommendations for designers.

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