Control rod drop-time reduction in typical swimming pool research reactors

2018 ◽  
Vol 106 ◽  
pp. 146-152
Author(s):  
M.R. Salmanpour Paean Afrakati ◽  
M. Gharib ◽  
S.M. Mirvakili
Keyword(s):  
Swimming Pool ◽  
Control Rod ◽  
Research Reactors ◽  
Drop Time ◽  
Time Reduction

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

scholarly journals Estimation of Control Rod Worth in a VVER-1000 Reactor using DRAGON4 and DONJON4

Nukleonika ◽  
2014 ◽  
Vol 59 (2) ◽  
pp. 67-72 ◽  
Author(s):  
Farahnaz Saadatian-derakhshandeh ◽  
Omid Safarzadeh ◽  
Amir Saiid Shirani
Keyword(s):  
Control Systems ◽  
Systems Design ◽  
Reactor Physics ◽  
Control Rod ◽  
Research Reactors ◽  
Best Estimate ◽  
Hazard Control ◽  
Control Systems Design ◽  
And Control ◽  
Good Agreement

Abstract One of the main issues in safety and control systems design of power and research reactors is to prevent accidents or reduce the imposed hazard. Control rod worth plays an important role in safety and control of reactors. In this paper, we developed a justifiable approach called D4D4 to estimate the control rod worth of a VVER-1000 reactor that enables to perform the best estimate analysis and reduce the conservatism that utilize DRAGON4 and DONJON4. The results are compared with WIMS-D4/CITATION to show the effectiveness and superiority of the developed package in predicting reactivity worth of the rod and also other reactor physics parameters of the VVER-1000 reactor. The results of this study are in good agreement with the plant's FSAR.

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.

A Method for RCCA Drop Analysis

2013 ◽  
Author(s):  
Tong Liu ◽  
Heng Huang ◽  
Peng Li ◽  
Wei Xu ◽  
Yuemin Zhou ◽  
...  
Keyword(s):  
Computer Program ◽  
Equations Of Motion ◽  
Control Rod ◽  
Structure Interaction ◽  
Fluid Resistance ◽  
Fuel Assemblies ◽  
Control Assembly ◽  
Drop Time ◽  
The Impact ◽  
Fluid Interaction

The control rod drop time is one of the most important parameters for safety analysis. The calculation accuracy of control rod drop time will be affected if ignoring the transverse vibration, which is mainly caused by the fluid-structure interaction between the RCCA (rod cluster control assembly)s, guide tubes and the fluid interaction. A new method for RCCA drop analysis is presented in this paper. The transverse equations of motion are established considering fluid-elastic structure interaction, assuming the fluid is incompressible laminar flow. And the vertical equations of motion are established considering the gravity force of RCCAs, the fluid resistance, and the friction force led by collision. A computer program based on this method is used to calculate the control rod drop time, the impact and the dynamic response of RCCA. The analysis results are compared with those of the in-house code, which is used for commercial design. It shows the computer program using the new models provides a useful tool in the design of RCCAs and fuel assemblies.

Drop Time Evaluation for SMART Control Rod Assembly

2011 ◽  
Vol 14 (2) ◽  
pp. 25-28
Author(s):  
Kyoung-Rean Kim ◽  
Ki-Jong Jang ◽  
Jin-Seok Park ◽  
Won-Jae Lee
Keyword(s):  
Control Rod ◽  
Smart Control ◽  
Drop Time ◽  
Time Evaluation

A PSA Case Study: Promoting the Reliability of the CRSS on the CMRR Through the ATWS Mitigation System

2018 ◽  
Author(s):  
Heng Yu ◽  
Guan-bo Wang ◽  
Da-zhi Qian ◽  
Yu-chuan Guo ◽  
Bo Hu
Keyword(s):  
Research Reactor ◽  
Control Rod ◽  
Research Reactors ◽  
The Core ◽  
Core Damage ◽  
The World ◽  
Safety Features ◽  
Control Rods ◽  
Pool Type

An increasing number of PSA programs concerning research reactors have been launched across the world. As with many other reactors, the CMRR (China Mianyang Research Reactor), a typical pool-type research reactor, regards the control rod shutdown system (CRSS) as its primary shutdown system which enables the reactor subcritical by dropping control rods into the core after a specific initiating event is detected. As a result, the CRSS is an essential ingredient of engineered safety features. It is necessary to enhance the reliability of the CRSS, ensuring the reactor can be successfully shut down when the ATWS — the anticipated transients without scram occurs. Therefore, additional facilities should be designed to cope with the extremely severe circumstance. Accordingly, the purpose of this paper is to evaluate the promotion of the CMRR’s safety degree and the reliability of its CRSS from the PSA’s perspective with an ATWS mitigation system installed. Results indicate that, by introducing the ATWS mitigation system, the failure probability of the CRSS can decrease from 1.52e−05 per demand to 3.35e−06 per demand, while the aggregate CDF (core damage frequency) induced by all IE (initiating event) groups, is able to decrease to a relatively low value 1.17e−05/y from its previous value 3.11e−06/y. It is apparent that the reliability of the CRSS as well as the safety degree of the overall reactor can be enhanced effectively by adding the ATWS mitigation system to the elementary design of the normal CRSS.

scholarly journals R&D on a Nonlinear Dynamics Analysis Code for the Drop Time of the Control Rod

2017 ◽  
Vol 2017 ◽  
pp. 1-6
Author(s):  
Daogang Lu ◽  
Yuanpeng Wang ◽  
Qingyu Xie ◽  
Huimin Zhang ◽  
Muhammed Ali
Keyword(s):  
Nonlinear Dynamics ◽  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Response Analysis ◽  
Safe Operation ◽  
Control Rod ◽  
Long Time ◽  
Drop Time ◽  
Dynamics Response

Whether the control rod can drop down in time is one of the important guarantees for the safe operation of the nuclear power plant. The drop-down process of the control rod is very complicated. For a long time, the researchers have done a lot of work on that, but it is hard to consider all the nonlinear factors. This paper considers the main factors together. Based on the theoretical analysis, we developed the nonlinear dynamics response analysis software for the nuclear power plant, which can be used to calculate the rod’s drop-down time. Compared with the results of the experiments, the software we developed proves to be applicable and reliable.

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