Research of the Rod Drop Time Based on the Control Rod System of TMSR-SF1

2017 ◽  
Author(s):  
Zuokang Lin ◽  
Lin Zhu ◽  
Chunfeng Zhao ◽  
Yun Cao ◽  
Xiao Wang
Keyword(s):  
Molten Salt ◽  
Similarity Criterion ◽  
Maximum Error ◽  
Driving Mechanism ◽  
Control Rod ◽  
Water Condition ◽  
Rod System ◽  
Drop Time ◽  
Control Rods ◽  
Reactor Accidents

The reactor scram function realized by the rapidly dropping of control rods ensures safety when the reactor accidents (loss of electricity and earthquake, etc.) happen. In the thorium base molten salt reactor (TMSR - SF1), the rod drop time is obviously affected by the resistance which produced in the molten salt as its high density and viscosity. In this paper, the drop time of the control rod is obtained by the theoretical and experimental methods for comparison. Firstly, the drop time is analyzed both in air and water condition with calculation and experiment. And the method used for the resistance calculation of the rod during dropping is verified. Secondly, the similarity criterion is adopted to calculate the drop time in molten salt condition. The study shows that: 1) In air and water condition, the calculation is coincidence with the experimental results within the maximum error less than 2 %. 2) The drop time of the rod in molten salt is 2.8 s with a dropping height 2.4m in reactor, which satisfy the safety requirement of the control system. 3) It is necessary to use another buffer beside the disc spring to protect the driving mechanism of the rod during the rod dropping.

Study on the Rod Drop Performance of High-Temperature Gas-Cooled Reactor

2014 ◽  
Author(s):  
He Yan ◽  
Xingzhong Diao
Keyword(s):  
High Temperature ◽  
Pressure Vessel ◽  
Reactor Core ◽  
Insertion Time ◽  
Operational Mode ◽  
Control Rod ◽  
Rod System ◽  
Key Factor ◽  
Control Rods ◽  
High Temperature Gas

In this paper, the theoretical study and experimental investigation on the rod drop performance of high-temperature gas-cooled reactor (HTGR) pebble-bed module have been presented. The control rod drive mechanisms (CRDMs), serving as the first shutdown system of the reactor, are positioned above the reactor pressure vessel. When the reactor is operated at the power regulation mode, the control rods are pulled up-and-down in their channels around the reactor core. The CRDM provides a fail-safe operational mode for the control rod system. If the reactor emergency shutdown is required the control rods could drop into their channels by gravity. Thus the key factor, emergency insertion time of the whole control rod stroke, which represents the inherent safety of the CRDM, is crucially important and should be measured precisely. In the final objective of ensuring reliability of the CRDM, a full size drive line had been built and tested to obtain the overall performance function of the CRDM. Every component of the CRDM test line was simulated at the scale 1:1, including a 15 meters high test bench that was used as the substitution of the pressure vessel. At current stage, the rod drop performance had been experimental investigated at ambient temperature and pressure. The emergency insertion time of an 8 meters stroke was measured to be less than 50 seconds. A mathematical model of CRDM also had been developed. The rod motion characteristic equations show that the rod dropping speed approaches to a constant during the emergency insertion. The theoretical results are in agreement with the test results.

Neutronic analysis of absorbing materials for the control rod system in reactor ALLEGRO

Kerntechnik ◽  
2016 ◽  
Vol 81 (4) ◽  
pp. 445-451
Author(s):  
F. Čajko ◽  
M. Sečanský ◽  
T. Chrebet ◽  
R. Zajac ◽  
P. Dařílek
Keyword(s):  
Control Rod ◽  
Rod System ◽  
Absorbing Materials

Calculation of phase diagrams and thermodynamic properties of 14 additive and reciprocal ternary systems containing Li2CO3, Na2CO3, K2CO3, Li2SO4, Na2SO4, K2SO4, LiOH, NaOH, and KOH

1984 ◽  
Vol 62 (3) ◽  
pp. 457-474 ◽  
Author(s):  
A. D. Pelton ◽  
C. W. Bale ◽  
P. L. Lin
Keyword(s):  
Phase Diagram ◽  
Thermodynamic Properties ◽  
Molten Salt ◽  
Phase Diagrams ◽  
Binary Systems ◽  
Ternary Phase ◽  
Ternary Phase Diagram ◽  
Ternary Systems ◽  
Maximum Error ◽  
Critical Assessment

Phase diagrams and thermodynamic properties of five additive molten salt ternary systems and nine reciprocal molten salt ternary systems containing the ions Li+, Na+, [Formula: see text], OH− are calculated from the thermodynamic properties of their binary subsystems which were obtained previously by a critical assessment of the thermodynamic data and the phase diagrams in these binary systems. Thermodynamic properties of ternary liquid phases are estimated from the binary properties by means of the Conformal Ionic Solution Theory. The ternary phase diagrams are then calculated from these thermodynamic properties by means of computer programs designed for the purpose. It is found that a ternary phase diagram can generally be calculated in this way with a maximum error about twice that of the maximum error in the binary phase diagrams upon which the calculations are based. If, in addition, some reliable ternary phase diagram measurements are available, these can be used to obtain small ternary correction terms. In this way, ternary phase diagram measurements can be smoothed and the isotherms drawn in a thermodynamically correct way. The thermodynamic approach permits experimental data to be critically assessed in the light of thermodynamic principles and accepted solution models. A critical assessment of error limits on all the calculated ternary diagrams is made, and suggestions as to which composition regions merit further experimental study are given.

Comparative Analysis of the Control Rod Drive System

2012 ◽  
Vol 614-615 ◽  
pp. 1558-1561
Author(s):  
Wen Wei Han ◽  
Wei Shi Han ◽  
Qing Guo
Keyword(s):  
Comparative Analysis ◽  
Drive System ◽  
Hydraulic Control ◽  
Control Rod ◽  
Rod System ◽  
Drive Systems ◽  
Research Situation

This article has systematically summarized the recent research situation of control rod system in China and comparatively analyzed the features of a variety of control rod drive systems on a basis of brief introduction of common types of control rod drive system. It has been proposed to that the hydraulic control rod drive system have a great potential in a wide application concerning on ships, warships power reactors and protable desalination system.

Predicting Thermal Mixing and Fatigue Inside Control Rod Guide Tubes

2013 ◽  
Author(s):  
Eric Lillberg
Keyword(s):  
Thermal Fatigue ◽  
Turbulent Mixing ◽  
Low Frequency ◽  
Experimental Measurements ◽  
Guide Tube ◽  
Control Rod ◽  
Thermal Mixing ◽  
Purge Flow ◽  
Control Rods ◽  
Good Agreement

The cracked control rods shafts found in two Swedish NPPs were subjected to thermal fatigue due to mixing of cold purge flow with hot bypass water in the upper part of the top tube on which the control rod guide tubes rests. The interaction between the jets formed at the bypass water inlets is the main source of oscillation resulting in low frequency downward motion of hot bypass water into the cold purge flow. This ultimately causes thermal fatigue in the control rod shaft in the region below the four lower bypass water inlets. The transient analyses shown in this report were done to further investigate this oscillating phenomenon and compare to experimental measurements of water temperatures inside the control rod guide tube. The simulated results show good agreement with experimental data regarding all important variables for the estimation of thermal fatigue such as peak-to-peak temperature range, frequency of oscillation and duration of the temperature peaks. The results presented in this report show that CFD using LES methodology and the open source toolbox OpenFOAM is a viable tool for predicting complex turbulent mixing flows and thermal loads.

scholarly journals A preliminary investigation of the molten salt mediated synthesis of Gd2TiO5 ‘stuffed’ pyrochlore

MRS Advances ◽  
2021 ◽  
Author(s):  
D. A. Austin ◽  
M. Cole ◽  
M. C. Stennett ◽  
C. L. Corkhill ◽  
N. C. Hyatt
Keyword(s):  
Molten Salt ◽  
Single Phase ◽  
Preliminary Investigation ◽  
Pyrochlore Phase ◽  
Comparative Investigation ◽  
Molten Salt Synthesis ◽  
Control Rods ◽  
First Time ◽  
Conventional Solid State Synthesis ◽  
Nuclear Applications

Abstract Refractory ‘stuffed’ pyrochlores such as Gd2TiO5 are of interest for nuclear applications, including as matrices for actinide disposition and as neutron absorbers in control rods. Here, we report the results of a preliminary comparative investigation of the synthesis of Gd2TiO5 by molten salt and conventional solid-state synthesis. We show that synthesis of Gd2TiO5 proceeds from the pyrochlore phase Gd2Ti2O7 which is first formed as a kinetic product. Molten salt synthesis afforded single phase Gd2TiO5 at 1300 °C in 2 h, via a template growth mechanism, and is effective for the synthesis of these refractory materials. This work demonstrates molten salt mediated synthesis of ‘stuffed’ pyrochlore for the first time. Graphic abstract

Estimation of control rod worth, xenon effect on reactivity and power defect of BAEC TRIGA Mark-II research reactor

2018 ◽  
Vol 33 (39) ◽  
pp. 1850233
Author(s):  
Md. Mehedi Hassan ◽  
K. M. Jalal Uddin Rumi ◽  
Md. Nazrul Islam Khan ◽  
Rajib Goswami
Keyword(s):  
Theoretical Analysis ◽  
Low Power ◽  
Temperature Effects ◽  
Research Reactor ◽  
Power Level ◽  
Fuel Temperature ◽  
Control Rod ◽  
Full Power ◽  
Triga Mark Ii ◽  
Control Rods

In this work, control rod worth, xenon (Xe) effect on reactivity and power defect have been measured by doing experiments in the BAEC TRIGA Mark-II research reactor (BTRR) and through established theoretical analysis. Firstly, to study the xenon-135 effect on reactivity, reactor is critical at 2.4 MW for several hours. Next, experiments have been performed at very low power (50 W) to avoid temperature effects. Moreover, for the power defect experiment, different increasing power level has been tested by withdrawing the control rods. Finally, it is concluded that the total control rods worth of the BAEC TRIGA Mark-II research reactor, as determined through this study, is enough to run the reactor at full power (3 MW) considering the xenon-135 and fuel temperature effects.

Development of REFT Code System for the Analysis of Highly Heterogeneous Research Reactors

2014 ◽  
Author(s):  
Tengfei Zhang ◽  
Hongchun Wu ◽  
Youqi Zheng ◽  
Liangzhi Cao ◽  
Yunzhao Li
Keyword(s):  
Least Square Method ◽  
Least Square ◽  
Core Analysis ◽  
Code System ◽  
Lattice Calculation ◽  
Control Rod ◽  
Research Reactors ◽  
The Core ◽  
User Friendly ◽  
Control Rods

As an effort to enhance the accuracy in simulating the operations of research reactors, a fuel management code system REFT was developed. Because of the possible complex assembly geometry and the core configuration of research reactors, the code system employed HELIOS in the lattice calculation to describe arbitrary 2D geometry, and used the 3D triangular nodal SN method transport solver, DNTR, to model unstructured geometry in the core analysis. Flux reconstruction with the least square method and micro depletion model for specific isotopes were incorporated in the code. At the same time, to make it more user friendly, a graphical user interface was also developed for REFT. In the analysis of the research reactors, the calculations involving the control rod movement are encountered frequently. The modeling of the control rods differential worth behavior is important in that the movement of the control rod may introduce variations on the reactivity. To handle the problem two effective ways of alleviating the control rod cusping effect are recently proposed, based on the established code system. The methodologies along with their application and validation will be discussed.

Measuring the Release Time and Total Drop Time of a Control Rod

1959 ◽  
Vol 6 (4) ◽  
pp. 328-332 ◽  
Author(s):  
Charles Zucker ◽  
Lewis Haring
Keyword(s):  
Release Time ◽  
Control Rod ◽  
Drop Time
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