scholarly journals Neutronic Performance of a Compact 10 MWe Nuclear Reactor with Low Enrichment (ThxU1−x)N Fuel

JOM ◽  
2021 ◽  
Author(s):  
S. S. Parker ◽  
S. Newman ◽  
A. J. Fallgren

AbstractRecent interest in compact nuclear reactors for applications in space or in remote locations drives innovation in nuclear fuel design, especially non-oxide ceramic nuclear fuels. This work details neutronic modeling designed to support the development of a new nuclear fuel concept based on a mixture of thorium and uranium nitride. A Monte Carlo N-Particle Version 6.2 (MCNP-6) model of a compact 10 MWe reactor design which incorporates (ThxU1−x)N fuel is presented. In this context, a “compact” reactor is a completely assembled reactor which may be emptied of coolant and transported by specialized commercial vehicle, deployed by a C130J aircraft, or launched into space. Core geometry, reflector barrels, and the heat exchange zones are designed to support reduction of overall reactor volume of core components while maintaining criticality with a fixed total fuel mass of 4500 kg. Dense mixed nitrides of thorium nitride (ThN) additions in uranium nitride (UN) in 5 wt.% increments between $$0.05 \le x \le 0.5$$ 0.05 ≤ x ≤ 0.5 have been considered for calculation of $$k_{\infty }$$ k ∞ and $$k_{{{\text{effective}}}}$$ k effective . ThN additions in UN results in a slight increase in the magnitude of the temperature coefficient of reactivity, which is negative by design. The isotopic distribution of the principal actinide inventory as a function of burnup, time, and initial fuel composition is presented and discussed within the context of the proliferation risk of this core design.

2021 ◽  
Vol 155 ◽  
pp. 108152
Author(s):  
Yahya A. Al-Zahrani ◽  
Khurram Mehboob ◽  
Daud Mohamad ◽  
Abdulsalam Alhawsawi ◽  
Fouad A. Abolaban

Author(s):  
A. S. Chinchole ◽  
Arnab Dasgupta ◽  
P. P. Kulkarni ◽  
D. K. Chandraker ◽  
A. K. Nayak

Abstract Nanofluids are suspensions of nanosized particles in any base fluid that show significant enhancement of their heat transfer properties at modest nanoparticle concentrations. Due to enhanced thermal properties at low nanoparticle concentration, it is a potential candidate for utilization in nuclear heat transfer applications. In the last decade, there have been few studies which indicate possible advantages of using nanofluids as a coolant in nuclear reactors during normal as well as accidental conditions. In continuation with these studies, the utilization of nanofluids as a viable candidate for emergency core cooling in nuclear reactors is explored in this paper by carrying out experiments in a scaled facility. The experiments carried out mainly focus on quenching behavior of a simulated nuclear fuel rod bundle by using 1% Alumina nanofluid as a coolant in emergency core cooling system (ECCS). In addition, its performance is compared with water. In the experiments, nuclear decay heat (from 1.5% to 2.6% reactor full power) is simulated through electrical heating. The present experiments show that, from heat transfer point of view, alumina nanofluids have a definite advantage over water as coolant for ECCS. Additionally, to assess the suitability of using nanofluids in reactors, their stability was investigated in radiation field. Our tests showed good stability even after very high dose of radiation, indicating the feasibility of their possible use in nuclear reactor heat transfer systems.


1998 ◽  
Vol 4 (S2) ◽  
pp. 772-773
Author(s):  
J.T. Busby ◽  
E.A. Kenik ◽  
G.S. Was

Radiation-induced segregation (RIS) is the spatial redistribution of elements at defect sinks such as grain boundaries and free surfaces during irradiation. This phenomenon has been studied in a wide variety of alloys and has been linked to irradiation-assisted stress corrosion cracking (IASCC) of nuclear reactor core components. However, several recent studies have shown that Cr and Mo can be enriched to significant levels at grain boundaries prior to irradiation as a result of heat treatment. Segregation of this type may delay the onset of radiation-induced Cr depletion at the grain boundary, thus reducing IASCC susceptibility. Unfortunately, existing models of segregation phenomena do not correctly describe the physical processes and therefore are grossly inaccurate in predicting pre-existing segregation and subsequent redistribution during irradiation. Disagreement between existing models and measurement has been linked to potential interactions between the major alloying elements and lighter impurity elements such as S, P, and B.


2018 ◽  
Vol 117 (sup1) ◽  
pp. s76-s81 ◽  
Author(s):  
Tashiema L. Wilson ◽  
Emily E. Moore ◽  
Denise Adorno Lopes ◽  
Vancho Kocevski ◽  
Elizabeth Sooby Wood ◽  
...  
Keyword(s):  

Author(s):  
Heriberto Sánchez-Mora ◽  
Carlos Chávez-Mercado ◽  
Chris Allison ◽  
Judith Hohorst

RELAP/SCDAPSIM is a nuclear reactor simulator and accident analysis code that has been used in the nuclear energy industry for many years. Currently, Innovative Systems Software is developing a new tool that will show the behavior of the core components during a simulation of an accident. The addition of contour plots for the SCDAP components showing different properties: temperature, hydrogen production, etc. will allow a better understanding of core behavior during a severe accident in a nuclear reactor. The SCDAP components are fuel rods, electrically heated simulator rods, such as those used in the CORA experiments, control rods, a shroud and a BWR blade/box. This paper describes the progress in the development of the contour plot tool based on the OpenGL and FORTRAN90 libraries. The purpose of this tool is help to the user analyze the simulation of an accident and to debug an input file.


Author(s):  
Vladyslav Soloviov

In this paper accounting of spent nuclear fuel (SNF) burnup of RBMK-1000 with actinides and full isotopic composition has been performed. The following characteristics were analyzed: initial fuel enrichment, burnup fraction, axial burnup profile in the fuel assembly (FA) and fuel weight. As the results show, in the first 400 hours after stopping the reactor, there is an increase in the effective neutron multiplication factor (keff) due to beta decay of 239Np into 239Pu. Further, from 5 to 50 years, there is a decrease in keff due to beta decay of 241Pu into 241Am. Beyond 50 years there is a slight change in the criticality of the system. Accounting for nuclear fuel burnup in the justification of nuclear safety of SNF systems will provide an opportunity to increase the volume of loaded fuel and thus significantly reduce technology costs of handling of SNF.


Author(s):  
Songyang Li ◽  
Dingqu Wang ◽  
Wenli Guo ◽  
Yueyuan Jiang

The duplex pellets under a “Low-Interact” (LOWI) nuclear fuel design, which consist of an outer enriched annulus and a depleted or natural core, can provide lower center temperature and reduced probability of pellet-clad mechanical interact (PCMI). Analysis and experiments were done in 1970s to examine the benefits and cost of LOWI design for water-cooled reactors. Results showed that the additional economic cost of this design should not be neglected in spite of the benefits. However, due to the improvement of nuclear fuel fabrication technology in the past 30 years, the benefits of LOWI design become more significant, especially when the potential of other methods to elevate the power density and overcome the constraints on ramp rates in power reactors is running out. In order to evaluate the feasibility of deploying the LOWI fuel in commercial and research reactors, neutronics and thermal calculations are made to figure out the performance of duplex UO2 pellets in particular reactors. It is shown that the center temperature of pellet has been greatly reduced without any change on assembly and core geometry, which means the opportunity of less fission gas production, higher power density and more adequate safety margin. A mechanical analysis of a typical LOWI design is also done. The challenges on duplex pellet manufacture are also discussed. Several fabrication techniques are presented to show the potential of cutting the cost of pellet production.


Author(s):  
Vladyslav Soloviov

In this paper accounting of spent nuclear fuel (SNF) burnup of RBMK-1000 only with actinides has been performed. The following characteristics were analyzed: initial fuel enrichment, burnup fraction, axial burnup profile in the fuel assembly (FA) and fuel weight. As the results show, in the first 400 hours after stopping the reactor, there is an increase in the effective neutron multiplication factor (keff) due to beta decay of 239Np into 239Pu. Further, from 5 to 50 years, there is a decrease in keff due to beta decay of 241Pu into 241Am. Beyond 50 years there is a slight change in the criticality of the system. Accounting for nuclear fuel burnup in the justification of nuclear safety of SNF systems will provide an opportunity to increase the volume of loaded fuel and thus significantly reduce technology costs of handling of SNF.


2012 ◽  
Vol 1383 ◽  
Author(s):  
Yang Zhong ◽  
Robert C. O’Brien ◽  
Steven D. Howe ◽  
Nathan D. Jerred ◽  
Kristopher Schwinn ◽  
...  

ABSTRACTThe feasibility of the fabrication of tungsten based nuclear fuel cermets via Spark Plasma Sintering (SPS) is investigated in this work. CeO2 is used to simulate fuel loadings of UO2 or Mixed-Oxide (MOX) fuels within tungsten-based cermets due to the similar properties of these materials. This study shows that after a short time sintering, greater than 90 % density can be achieved, which is suitable to possess good strength as well as the ability to contain fission products. The mechanical properties and the densities of the samples are also investigated as functions of the applied pressures during the sintering.


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