HTGR Power-Level Control Only by Regulating Helium Flowrate

2020 ◽  
Author(s):  
Zhe Dong
Keyword(s):  
Neutron Flux ◽  
Closed Loop ◽  
Power Level ◽  
Negative Temperature ◽  
Helium Temperature ◽  
Level Control ◽  
Outer Loop ◽  
Satisfactory Performance ◽  
Temperature Feedback ◽  
Control Rods

Abstract Currently, most of the power-level control methods of nuclear reactors are given based upon the scheme of inducing reactivity directly via control rods. However, the reactivity can also be injected indirectly via the negative temperature feedback effect. Motivated by this, a cascaded power-level control of high temperature gas-cooled reactor (HTGR) is proposed by only regulating primary helium flowrate, which can be able to provide globally asymptotical closed-loop stability. This new HTGR power-level control is composed by a helium temperature controller and a neutron flux controller. The former controller, which is located in the inner loop, regulates the primary helium flowrate according to the setpoint of helium temperature. While, the latter one in the outer loop revises the setpoint of helium temperature so as to regulate neutron flux. Numerical simulation results verify the theoretical result while showing the satisfactory performance as well as the influence from the controller parameters.

Power level control of CANDLE reactor without control rods

2014 ◽  
Vol 63 ◽  
pp. 427-431 ◽  
Author(s):  
Hiroshi Sekimoto ◽  
Sinsuke Nakayama
Keyword(s):  
Power Level ◽  
Level Control ◽  
Control Rods

scholarly journals The Transient Reactor Test Facility (TREAT)

2021 ◽  
Author(s):  
Nicolas Woolstenhulme
Keyword(s):  
Negative Temperature ◽  
Test Facility ◽  
Design History ◽  
New Era ◽  
Safety Research ◽  
Temperature Feedback ◽  
Reactor Test ◽  
Transient Control ◽  
Reactor Types ◽  
Control Rods

Constructed in the late 1950s, the Transient Reactor Test facility (TREAT) provided numerous transient irradiations until operation was suspended in 1994. It was later refurbished, and resumed operations in 2017 to meet the data needs of a new era of nuclear fuel safety research. TREAT uses uranium oxide dispersed in graphite blocks to yield a core that affords strong negative temperature feedback. Automatically controlled, fast-acting transient control rods enable TREAT to safely perform extreme power maneuvers—ranging from prompt bursts to longer power ramps—to broadly support research on postulated accidents for many reactor types. TREAT’s experiment devices work in concert with the reactor to contain specimens, support in situ diagnostics, and provide desired test environments, thus yielding a uniquely versatile facility. This chapter summarizes TREAT’s design, history, current efforts, and future endeavors in the field of nuclear-heated fuel safety research.

Control Strategies for a Highly Loaded Biological Ammonia Elimination Process

1993 ◽  
Vol 28 (11-12) ◽  
pp. 531-538 ◽  
Author(s):  
B. Teichgräber
Keyword(s):  
Closed Loop ◽  
Control Strategies ◽  
Level Control ◽  
Sludge Dewatering ◽  
Loop Control ◽  
Reject Water ◽  
Line Measurement ◽  
Control Pattern ◽  
On Line ◽  
Treatment Facilities

A nitrification/denitrification process was applied to reject water treatment from sludge dewatering at Bottrop central sludge treatment facilities of the Emschergenossenschaft. On-line monitoring of influent and effluent turbidity, closed loop control of DO and pH, and on-line monitoring of nitrogen compounds were combined to a three level control pattern. Though on-line measurement of substrate and product showed substantial response time it could be used to operate nitrification/denitrification within process boundaries.

scholarly journals Modeling and Reconstruction of State Variables for Low-Level Control of Soft Pneumatic Actuators

2021 ◽  
Vol 8 ◽  
Author(s):  
Serhat Ibrahim ◽  
Jan Christoph Krause ◽  
Alexander Olbrich ◽  
Annika Raatz
Keyword(s):  
Inertial Measurement Unit ◽  
Closed Loop ◽  
Measurement Unit ◽  
Closed Loop Control ◽  
State Variables ◽  
Level Control ◽  
Pneumatic Actuators ◽  
Loop Control ◽  
Inertial Measurement ◽  
Low Level

To further advance closed-loop control for soft robotics, suitable sensor and modeling strategies have to be investigated. Although there are many flexible and soft sensors available, the integration into the actuator and the use in a control loop is still challenging. Therefore, a state-space model for closed-loop low-level control of a fiber-reinforced actuator using pressure and orientation measurement is investigated. To do so, the integration of an inertial measurement unit and geometric modeling of actuator is presented. The piecewise constant curvature approach is used to describe the actuator’s shape and deformation variables. For low-level control, the chamber’s lengths are reconstructed from bending angles with a geometrical model and the identified material characteristics. For parameter identification and model validation, data from a camera tracking system is analyzed. Then, a closed-loop control of pressure and chambers’ length of the actuator is investigated. It will be shown, that the reconstruction model is suitable for estimating the state variables of the actuator. In addition, the use of the inertial measurement unit will demonstrate a cost-effective and compact sensor for soft pneumatic actuators.

scholarly journals Open-closed Iterative Learning Control Algorithm for Exoskeleton Rehabilitation Purposes

2019 ◽  
Vol 292 ◽  
pp. 01010
Author(s):  
Mihailo Lazarević ◽  
Nikola Živković ◽  
Darko Radojević
Keyword(s):  
Iterative Learning Control ◽  
Control Algorithm ◽  
Closed Loop ◽  
Learning Control ◽  
Open Loop ◽  
Iterative Learning ◽  
Control Law ◽  
Exact Linearization ◽  
Outer Loop ◽  
Control Scheme

The paper designs an appropriate iterative learning control (ILC) algorithm based on the trajectory characteristics of upper exosk el eton robotic system. The procedure of mathematical modelling of an exoskeleton system for rehabilitation is given and synthesis of a control law with two loops. First (inner) loop represents exact linearization of a given system, and the second (outer) loop is synthesis of a iterative learning control law which consists of two loops, open and closed loop. In open loop ILC sgnPDD2 is applied, while in feedback classical PD control law is used. Finally, a simulation example is presented to illustrate the feasibility and effectiveness of the proposed advanced open-closed iterative learning control scheme.

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