scholarly journals Safety Analysis of Small Modular Natural Circulation Lead-Cooled Fast Reactor SNCLFR-100 Under Unprotected Transient

2021 ◽  
Vol 9 ◽  
Author(s):  
Chao Guo ◽  
Pengcheng Zhao ◽  
Jian Deng ◽  
Hongxing Yu
Keyword(s):  
Fuel Assembly ◽  
Flow Rate ◽  
Fast Reactor ◽  
Optimization Design ◽  
Natural Circulation ◽  
Coolant Flow ◽  
Coolant Flow Rate ◽  
Design Stage ◽  
Large Power ◽  
The Core

SNCLFR-100 is a small modular natural circulation lead-cooled fast reactor, developed by University of Science and Technology of China, aiming at taking full advantage of the good economics and inherent safety of lead-cooled fast reactors to develop miniaturized, lightweight and multi-purpose special nuclear reactor technology. SNCLFR-100 is still in the conceptual design stage, in order to fully evaluate the safety features of the reactor and provide reference for the optimization design of the next stage, three typical transients are selected based on the analysis of the SNCLFR-100 initiating events by using the code Analysis of Thermal-hydraulics of Leaks and Transients (ATHLET), which are unprotected transient overpower (UTOP), unprotected loss of heat sink (ULOHS) and unprotected partial blockage in the hottest fuel assembly. For UTOP, the unexpected positive reactivity insertion of 0.7$ in 15s led to two large power peaks in the core quickly, and then the core power began to decrease and gradually stabilized under the action of various of negative feedbacks of the reactor, the peak temperatures of fuel and cladding rose rapidly with the increase of core power and eventually stabilized at a higher temperature. For ULOHS, as the reactor were driven by natural circulation, the coolant mass flow rate continued to decline after the transient, both core and cladding temperatures rose quickly and the temperature rise were smaller than that of UTOP transient, the reactor shutdown by itself and the peak temperatures of fuel and cladding were smaller than the safety limit. For unprotected partial blockage in the hottest fuel assembly, with the increase of the blockage rate of the hottest fuel assembly inlet, the coolant flow rate, the peak temperatures of coolant, fuel and cladding increased significantly, when the blockage rate increased to 0.9, the coolant flow rate of the hottest fuel assembly dropped to about 12.6% of the normal value, and the cladding peak temperature would exceed the cladding melting point, measures should be taken to avoid the happening of severe accident.

Investigation on Multi-Objective Optimal Design of a Two Pass Condenser

2013 ◽  
Author(s):  
Lei Chen ◽  
Chang-qi Yan ◽  
Jian-jun Wang
Keyword(s):  
Flow Rate ◽  
Optimization Design ◽  
Optimization Techniques ◽  
Coolant Flow ◽  
Geometric Constraints ◽  
Coolant Flow Rate ◽  
Coolant Temperature ◽  
Outer Diameter ◽  
Pressurized Water ◽  
Multi Objective

Condenser is one of the key components in nuclear power plant with pressurized water reactor. It is important to control the dimension and weight in the design of condenser through optimization techniques. In this paper, a mathematic model of a two pass condenser is set up for Qinshan I condenser. Some modifications are made based on the original multi-objective algorithm, and the comparison between modified algorithm and the original one is conducted. Furthermore, the multi-objective optimization design of the condenser, taking minimization of the coolant flow-rate and net weight as objectives, is carried out considering thermohydraulic and geometric constraints through hybrid Pareto-sorting multi-objective genetic algorithm (HPSMOGA). The sensitivities of some parameters, which may influence the coolant flow-rate and the net weight of condenser, are also analyzed. The results show that the mathematical model is agreeable for the condenser. it is also shown that the proposed multi-objective optimal method is more effective in searching non-dominated solutions. the sensitivity analysis show that the tube outer diameter, tube pitch, coolant velocity and coolant temperature rising influence the coolant flow-rate and net weight of the condenser more than other variables. The corresponding results would provide guidance in the engineering design of this type of condenser.

Preliminary Study of Safety Analysis of Pb-Bi Cooled Small Power Reactor with Natural Circulation

2013 ◽  
Vol 772 ◽  
pp. 519-523
Author(s):  
Novi Trian ◽  
Abdul Waris ◽  
Sparisoma Viridi ◽  
Su'ud Zaki
Keyword(s):  
Flow Rate ◽  
Power Reactor ◽  
Natural Circulation ◽  
Safety Analysis ◽  
Coolant Flow ◽  
Coolant Flow Rate ◽  
Outlet Temperature ◽  
Small Power ◽  
Optimum Height ◽  
Lead Bismuth Eutectic

We report our study of the safety analysis in design of small power reactor which design based on the concept of a long-life core reactor cooled by lead-bismuth eutectic (LBE). The motivation of these studies is in order to design a next generation of reactors, we need to design a type of reactor that has inherent safety. We designed the small Pb-Bi cooled reactor with MOX-Nitrate as a fuel. In order to study the safety analysis of this reactor we conducted studies of chimney length effect to coolant flow rate in natural circulation and dependency of outlet temperature with coolant flow rate. From this work we obtained the optimum height of chimney at 15 m for the lead-bismuth eutectic flow rate 3500 kg/s and also we found the dependency of outlet temperature with lead-bismuth eutectic flow rate.

scholarly journals Thermal-hydraulic calculations for a fuel assembly in a European Pressurized Reactor using the RELAP5 code

Nukleonika ◽  
2015 ◽  
Vol 60 (3) ◽  
pp. 537-544
Author(s):  
Maciej Skrzypek ◽  
R. Laskowski
Keyword(s):  
Fuel Assembly ◽  
Flow Rate ◽  
Transient State ◽  
Steady States ◽  
Coolant Flow ◽  
Coolant Flow Rate ◽  
Normal Operation ◽  
Technical Documentation ◽  
Design Data ◽  
Relap5 Code

Abstract The main object of interest was a typical fuel assembly, which constitutes a core of the nuclear reactor. The aim of the paper is to describe the phenomena and calculate thermal-hydraulic characteristic parameters in the fuel assembly for a European Pressurized Reactor (EPR). To perform thermal-hydraulic calculations, the RELAP5 code was used. This code allows to simulate steady and transient states for reactor applications. It is also an appropriate calculation tool in the event of a loss-of-coolant accident in light water reactors. The fuel assembly model with nodalization in the RELAP5 (Reactor Excursion and Leak Analysis Program) code was presented. The calculations of two steady states for the fuel assembly were performed: the nominal steady-state conditions and the coolant flow rate decreased to 60% of the nominal EPR flow rate. The calculation for one transient state for a linearly decreasing flow rate of coolant was simulated until a new level was stabilized and SCRAM occurred. To check the correctness of the obtained results, the authors compared them against the reactor technical documentation available in the bibliography. The obtained results concerning steady states nearly match the design data. The hypothetical transient showed the importance of the need for correct cooling in the reactor during occurrences exceeding normal operation. The performed analysis indicated consequences of the coolant flow rate limitations during the reactor operation.

scholarly journals Deterministic Analysis of Natural Circulation Events at the Ignalina NPP

2008 ◽  
Vol 2008 ◽  
pp. 1-9
Author(s):  
Algirdas Kaliatka ◽  
Eugenijus Uspuras ◽  
Virginijus Vileiniskis
Keyword(s):  
Flow Rate ◽  
Nuclear Power ◽  
Natural Circulation ◽  
Reactor Core ◽  
Coolant Flow ◽  
Coolant Flow Rate ◽  
Normal Operation ◽  
Main Question ◽  
Forced Circulation ◽  
Main Circulation

Eight main circulation pumps (MCPs) are employed for the cooling of water forced circulation through the RBMK-1500 reactor at the Ignalina nuclear power plant (NPP). These pumps are joined into groups of four pumps each (three for normal operation and one on standby). In the case of all MCPs trip, the reactor shutdown system is activated due to decrease of coolant flow rate. At the same time, after the pump trip, the coolant to the reactor fuel channels during the first few seconds is supplied by pump coastdown. Later, the reactor is cooled by natural circulation. The main question arises whether this coolant flow rate is sufficient to remove the decay heat from the reactor core. This paper presents the investigation of all MCPs trip events at the Ignalina NPP by employing best estimate code RELAP5 and methodology of uncertainty and sensitivity analysis.

Effect of Outer Fin Axial Gap on the Sealing Effectiveness and Fluid Dynamics of Radial Rim Seal

2017 ◽  
Author(s):  
Zhigang Li ◽  
Jun Li ◽  
Liming Song ◽  
Qing Gao ◽  
Xin Yan ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Flow Rate ◽  
Gas Turbines ◽  
Flow Behavior ◽  
Three Dimensional ◽  
Numerical Approach ◽  
Coolant Flow ◽  
Coolant Flow Rate ◽  
Navier Stokes ◽  
Hot Gas

The modern gas turbine is widely applied in the aviation propulsion and power generation. The rim seal is usually designed at the periphery of the wheel-space and prevented the hot gas ingestion in modern gas turbines. The high sealing effectiveness of rim seal can improve the aerodynamic performance of gas turbines and avoid of the disc overheating. Effect of outer fin axial gap of radial rim seal on the sealing effectiveness and fluid dynamics was numerically investigated in this work. The sealing effectiveness and fluid dynamics of radial rim seal with three different outer fin axial gaps was conducted at different coolant flow rates using three-dimensional Reynolds-Averaged Navier-Stokes (RANS) and SST turbulent model solutions. The accuracy of the presented numerical approach for the prediction of the sealing performance of the turbine rim seal was demonstrated. The obtained results show that the sealing effectiveness of radial rim seal increases with increase of coolant flow rate at the fixed axial outer fin gap. The sealing effectiveness increases with decrease of the axial outer fin gap at the fixed coolant flow rate. Furthermore, at the fixed coolant flow rate, the hot gas ingestion increases with the increase of the axial outer fin gap. This flow behavior intensifies the interaction between the hot gas and coolant flow at the clearance of radial rim seal. The preswirl coefficient in the wheel-space cavity is also illustrated to analyze the flow dynamics of radial rim seal at different axial outer fin gaps.

Simulation on the Temperature Field of Milling Roller Using Fluent Software

2015 ◽  
Vol 1095 ◽  
pp. 846-850
Author(s):  
Min Wang ◽  
Ke Ping Zhang ◽  
Feng Wei Zhang
Keyword(s):  
Temperature Field ◽  
Flow Rate ◽  
Coolant Flow ◽  
Coolant Flow Rate ◽  
Roller Surface ◽  
Fluent Software ◽  
The Law

In order to study the law between the internal coolant flow rate and the temperature of milling roller, the temperature field of water-cooled roller was simulated with Fluent software. The results showed that with the increase of the coolant flow rate, the temperature on roller surface decreased, but after the flow rate of coolant increased to 3.5 kg/s, the temperature of roller maintained invariant almost, so 3.5 kg/s was the best flow rate.

Numerical Studies on the Effect of Tip Clearance and Tip Cooling Flow on Endwall Losses of an Unshrouded Axial Turbine Rotor

2013 ◽  
Author(s):  
K. Asgar Ali ◽  
Quamber H. Nagpurwala ◽  
Abdul Nassar ◽  
S. V. Ramanamurthy
Keyword(s):  
Flow Rate ◽  
Layer Growth ◽  
Coolant Flow ◽  
Tip Clearance ◽  
Coolant Flow Rate ◽  
Total Efficiency ◽  
Turbine Stage ◽  
Suction Surface ◽  
Axial Turbine ◽  
Ejection Rate

This paper deals with the numerical investigations on a low pressure axial turbine stage to assess the effect of variation in rotor tip clearance and tip coolant ejection rate on the end wall losses. The rotor, along with the NGV, was modeled to represent the entire turbine stage. The CFX TASCflow software was used to perform steady state analysis for different rotor tip clearances and different tip coolant ejection rates. The locations of the cooling slots were identified on the blade tip and the coolant ejection rate was specified at these areas. The simulations were carried out with tip clearances of 0%, 1% and 2% of blade height and ejection flow rates of 0.5%, 0.75% and 1% of main turbine flow rate. It is shown that the size and strength of the leakage vortex is directly related to the tip clearance. The reduction in efficiency is not in linearity with the tip clearance owing to the effect of boundary layer growth on the end walls. Introduction of the tip coolant flow shows increased total–total efficiency compared to that of the uncooled tip. This is attributed to a reduction in the strength of the leakage vortex due to reduced cross-flow over the tip clearance from pressure surface to suction surface. At a coolant flow rate of 0.75% of the main flow rate, there is significant increase in efficiency of about 0.5%. Optimum tip clearance and coolant flow rate are obtained based on the results of the present analysis.

Effects of Endwall Film Coolant Flow Rate on Secondary Flows and Coolant Mixing in a First Stage Nozzle Guide Vane

2021 ◽  
Author(s):  
Mahmood Alqefl ◽  
Kedar Nawathe ◽  
Pingting Chen ◽  
Rui Zhu ◽  
Yong Kim ◽  
...  
Keyword(s):  
Flow Rate ◽  
Guide Vane ◽  
Secondary Flows ◽  
Coolant Flow ◽  
Coolant Flow Rate ◽  
Nozzle Guide Vane ◽  
Nozzle Guide
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