scholarly journals Decay Heat Generation by Fission Products and 233Pa in a Single-Region Molten Salt Reactor

1968 ◽  
Author(s):  
W. L. Carter
Keyword(s):  
Molten Salt ◽  
Heat Generation ◽  
Fission Products ◽  
Molten Salt Reactor ◽  
Decay Heat ◽  
Single Region

scholarly journals SIMULATION OF BREED AND BURN FUEL CYCLE OPERATION OF MOLTEN SALT REACTOR IN BATCH-WISE REFUELING MODE

2021 ◽  
Vol 247 ◽  
pp. 13003
Author(s):  
Valeria Raffuzzi ◽  
Jiri Krepel
Keyword(s):  
Molten Salt ◽  
Fuel Cycle ◽  
Fission Products ◽  
Molten Salt Reactor ◽  
Core Size ◽  
Spent Fuel ◽  
Fluid Core ◽  
Active Core ◽  
Breed And Burn ◽  
Gen Iv

The Molten Salt Reactor (MSR) is one of the most revolutionary Gen-IV reactors and it can be operated, especially with chloride salts, in the so-called breed and burn fuel cycle. In this type of fuel cycle the fissile isotopes from spent fuel do not need to be reprocessed, because the excess bred fuel covers the losses. The liquid phase of the MSR fuel assures its instant homogenization, and the reactor can be operated with batch-wise refueling thus reaching an equilibrium state. At the same time, the active core of the chloride fast MSR needs to be bulky to limit neutron leakage. In this study, the code Serpent 2 was coupled to the Python script BBP to simulate batch-wise operation of the breed and burn MSR fuel cycle. The script, previously developed for solid assemblies shuffling, was modified to simulate fuel homogenization after fertile material addition. Several fuel salts and fission products removal strategies were simulated and their impact was analyzed. Similarly, the influence of blanket volume was assessed in a two-fluid core layout. The results showed that the reactivity initially grows during the irradiation period and later decreases. The blanket has a large impact on the performance and it can be used to further increase the fuel burnup or to shrink the active core size. The breed and burn fuel cycle in MSR can reach high fuel utilization without fuel reprocessing and a multi-fluid layout can help to decrease the core size.

Transient Analyses of Passive Residual Heat Removal System of 10MW Molten Salt Reactor Experiment

2014 ◽  
Vol 953-954 ◽  
pp. 621-626
Author(s):  
Hang Bin Zhao ◽  
Chang Qi Yan ◽  
Li Cheng Sun ◽  
Kai Bin Zhao
Keyword(s):  
Molten Salt ◽  
Power Plants ◽  
Heat Removal ◽  
Molten Salt Reactor ◽  
Inherent Safety ◽  
Decay Heat ◽  
Reactor Experiment ◽  
Heat Removal System ◽  
Removal System ◽  
Residual Heat

In order to improve the inherent safety of the Molten Salt Reactor (MSR), a concept of passive residual heat removal system (PRHRS) for the 10MW Molten Salt Reactor Experiment (MSRE) was put forward. Its transient characteristics were investigated by developing a model of it using C++ code. The effects of environmental temperature, finned tube number and chimney height on the PRHRS were analyzed. The results show that the PRHRS can remove the decay heat timely. Three natural circulations are established in the PRHRS when it begins to operate. With the decay heat power reducing, the PRHRS can automatically adjust its heat removal ability. It needs not any external power for the PRHRS to operate, which enhances the inherent safety and reliability of the reactor, especially under the condition that power plants lose power.

Study on dynamic characteristics of fission products in 2 MW molten salt reactor

2020 ◽  
Vol 31 (2) ◽  
Author(s):  
Bo Zhou ◽  
Xiao-Han Yu ◽  
Yang Zou ◽  
Pu Yang ◽  
Shi-He Yu ◽  
...  
Keyword(s):  
Molten Salt ◽  
Dynamic Characteristics ◽  
Fission Products ◽  
Molten Salt Reactor

Preliminary Thermal-Hydraulic Analyses for Designing an Experimental Model of a Molten Salt Reactor Concept

2013 ◽  
Author(s):  
Bogdán Yamaji ◽  
Attila Aszódi
Keyword(s):  
Molten Salt ◽  
Fast Reactor ◽  
Three Dimensional ◽  
Internal Heat ◽  
Molten Salt Reactor ◽  
Cfd Modelling ◽  
Scaled Model ◽  
Experimental Modelling ◽  
The Core ◽  
Single Region

Based on the MSFR (Molten Salt Fast Reactor) reactor concept presented within the framework of the EVOL (Evaluation and Viability of Liquid Fuel Fast Reactor System, EU FP7) international research project preliminary three-dimensional thermal-hydraulic analyses and the discussion of scaled experimental modelling will be presented. The MSFR concept is a single region, homogeneous liquid fuelled fast reactor. The reactor concept uses fluoride-based molten salts with fissile uranium and/or thorium and other heavy nuclei content with the purpose of applying the thorium cycle and the burn-up of transuranic elements. The concept has a single region cylindrical core with sixteen radial inlet and outlet nozzles located at the bottom and top of the core. The external circuit (internal heat exchanger, pump, pipes) is broken up into sixteen identical modules distributed around the core. Purpose of the three-dimensional computational fluid dynamics (CFD) calculations is to study the possibility of experimental investigation of the fluid flow in the core of the proposed MSFR concept using a scaled model and Particle Image Velocimetry (PIV) flow measurement technique. First the main properties of the proposed MSFR concept are introduced, and the information on other experimental thermal-hydraulic modelling of different reactors, including MSRE (Molten Salt Reactor Experiment) are summarised. With a scaled plexiglas MSFR model it would be possible to carry out flow field measurements under laboratory conditions using PIV method. Possible way of scaling are presented and a series of preliminary CFD calculations are discussed. Possibilities and limitations of such scaling and segmenting of a model and the use of water as substitute fluid for the experimental mock-up will be discussed. Objectives of such a measurement series would be validation, benchmarking of CFD calculations and codes, application of CFD modelling experience in the detailed thermal-hydraulic design of the MSFR concept, possible measurements for the study of specific problems or phenomena, for example refinement of inlet geometry, effects of internal structures, coolant mixing.

Natural Convection With Non-Uniform Heat Generation in Molten Salt Reactor

2009 ◽  
Author(s):  
Libo Qian ◽  
Suizheng Qiu ◽  
Dalin Zhang ◽  
Guanghui Su
Keyword(s):  
Natural Convection ◽  
Rayleigh Number ◽  
Molten Salt ◽  
Heat Generation ◽  
Dimensionless Temperature ◽  
Molten Salt Reactor ◽  
Closed Cavity ◽  
Dimensionless Velocity ◽  
Fuel Salt ◽  
Salt Flow

The Molten Salt Reactor (MSR) is one of the six Generation IV systems capable of breeding and transmutation of actinides and long-lived fission products, which uses the liquid molten salt as the fuel solvent, coolant and heat generation simultaneously. The MSR neutronics, such as the distribution of the delay neutron precursors (DNP), is significantly influenced by the fluid flow, which is quite different from the conventional reactors. Therefore, it is very important to do some research on MSR, especially in accident conditions. The present paper studies the natural convection through which the heat generated by the fuel is removed out of the core region (simply a square cavity in this paper). The neutronic theoretical model is founded based on the conservation law, which consists of two-group neutron diffusion equation for the fast and thermal neutron fluxes and that for one-group DNP, in which the convection terms are included to reflect the fuel salt flow. The SIMPLER numerical method was used to calculate the natural convection heat transfer to the molten salt inside a closed cavity for which the boundary temperature was spatially uniform. The equations were discretized by finite volume method based on collocated grids, in which QUICK defect correction was adopted for the convection terms and the central difference was for the diffusion terms. The discretization equations were calculated by ADI (Alternative Direction Implicit) with block-correction technique. The distributions of the dimensionless temperature, the dimensionless velocity, the fluxes and the DNP in the cavity were obtained. The calculated results showed that: a) the distribution of the DNP was correlated both with that of the fluxes and with the fuel salt flow and when Rayleigh number increased, the latter one was of much more importance; b) the distribution of the local Nusselt number varied with different Rayleigh numbers; c) the distribution of the dimensionless velocity and the dimensionless temperature were also closely related to Rayleigh number; d) the maximum dimensionless temperature decreased as Rayleigh number increases.

scholarly journals MAXIMISING DISCHARGE BURNUP IN AN OPEN CYCLE MOLTEN SALT REACTOR

2021 ◽  
Vol 247 ◽  
pp. 12002
Author(s):  
Charlie Constable ◽  
Ben Lindley ◽  
Geoff Parks
Keyword(s):  
Molten Salt ◽  
Fission Products ◽  
Molten Salt Reactor ◽  
The Core ◽  
Unit Cells ◽  
Internal Set ◽  
Open Cycle ◽  
Set Up ◽  
Work Done ◽  
Graphite Moderator

This paper discusses work done to find an estimate of the maximum achievable discharge burnup in an open cycle molten salt reactor (MSR). An in-development deterministic code (WIMS11) is used to create a model of a simple generic MSR, and the methodology employed is discussed. Some experimentation is done with regards to the internal set-up of the ‘unit cells’ within the core, which shows there is a strong link between this geometry and the achievable burnup. Work is done to quantify the effects of removing volatile fission products and implementing a two-batch refuelling scheme. Finally, an optimization process is carried out whereby the optimal proportion of graphite moderator within the core is found which balances power across the regions while maximising discharge burnup. Two fuels are tested, one which carries only 235U and 238U, and another which also carries 232Th. It is found that the maximum achievable discharge burnup is approximately 155 MWd/kg, which is considerably higher than modern PWRs, despite a lower enrichment and only two batches of fuel being used.

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