Reactor power control

MONJU (Japan) power control on outlet temperature or manual 

BN-600 (Russian Federation) automatic power control on outlet Na and steam temperature 

Super-Phenix 1 (France) base load operation 

---

Our present discussions relate only to the laboratory testing of safety-related secondary systems, as are employed in critical areas such as areas of emergency power supply and reactor power control supply etc. of a nuclear power plant (NPP) according to IEEE 344 and lEC 60980. There are other codes also but IEEE 344 is referred to more commonly. Basically, all such codes are meant for an NPP but they can be applied to other critical applications or installations that are prone to earthquakes. 

One is the secondary- coolant reduction test by partial secondary loss of coolant flow in order to simulate the load change of the nuclear heat utilization system. This test will demonstrate that the both of negative reactivity feedback effect and the reactor power control system brings the reactor power safely to a stable level without a reactor scram, and that the temperature transient of the reactor core is slow in a decrease of the secondary coolant flow rate. The test will be perfonned at a rated operation and parallel-loaded operation mode. The maximum reactor power during the test will limit within 30 MW (100%). In this test, the rotation rate of the secondary helium circulator will be changed to simulate a temperature transient of the heat utilisation system in addition to cutting off the reactor-inlet temperature control system. This test will be performed under anticipated transients without reactor scram (ATWS). 

Plant Control, Data, Reactor power control. 

The moderator boron concentration is used for slow reactivity changes and for establishing the upper limit of a reactor power control range. It is also used for rapid shutdown by opening scram valves that let borated reactor pool water into the primary loop -at the coolant pump... 

For small power reductions (less than a 10% change in load), the turbine bypass system is not actuated. Instead, it is accommodated by the reactor power control, the pressuriser level control, the pressuriser pressure control and the steam generator level control systems. 

The plant control system provides the fimctions necessary for normal operation of the plant, from cold shutdown through to full power. This system controls the duty systems in the plant, which are operated from the main eontrol room or remote shutdown woikstation. The plant control system contains the control and instmmentation needed to change reactor power, control pressuriser pressure and level, eontrol feed water flow, turbine control and perform other plant fimetions associated with power generation. 

To ensure the function of reactor power control, two independent systems based on diverse drive mechanisms are provided for reactor shutdown. One system acts as an accident protection system, while the actuated second system is designed to provide guaranteed subcriticality for an unlimited period of time and to be able to account for any reactivity effects including those in accidental states. Either system can operate under the failure of a minimum of one rod with maximum worth. In case of loss of power to the reactor control and protection system (RCP), all rods of this system can be inserted in the core under the effect of gravity. 

Outer control rods in the replaceable reflector region to support reactor power control and... 

PWR Reactor following turbine Turbine control valves Reactor power Control rods... 

Fig. 4.24 Calculation results for tuning maximum deviation for proportional control in reactor power control system...

The instrumentation and control system of the JRR-3M consists of its constituent systems of neutron instrumentation, process instrumentation, reactor power control, reactor protection, engineered safety feature stating and process radioactivity monitoring The system is designed and constructed under the laws, standards and criteria of those days with a satisfactory quality assurance program A specific feature of the system is an extensive introduction of computer systems with a process computer and a management computer This contributes to lightening operators loads satisfactorily... 

The reactor power control system consists of a reactivity control system, the linear power monitoring channels of the neutron instrumentation system and the reactor shut-down (control rod system) It is designed to automatically operate control rods to compensate reactivity changes caused by loading and unloading of irradiation samples, accumulation of Xenon, changes of coolant temperature, bum-up of fuels and so on in reactor operation... 

---