T. Jayanthi

Real time simulation and analysis of nuclear core temperature monitoring system for PFBR

Real time simulation of process models are in heavy demand in the present day industrial scenario especially in Nuclear Power Plant scenario. Nuclear core being the most important and critical component in the Nuclear reactor, the primary concern is towards safe and efficient operation of the reactor by adopting better techniques for monitoring and control of the reactor. Effort is on at global level to develop and build a Training Simulator, covering all the reactor subsystems to impart comprehensive training to Nuclear Power Plant operators. This paper describes about the importance of Core Temperature Monitoring System for Prototype Fast Breeder Reactor (PFBR), real time modeling and simulation of core temperature monitoring system, the basic requirements and methodologies adopted for modeling and simulation. The simulation includes run time calculation for all the fuel subassemblies (SA) outlet temperature and plugging or flow blockage of fuel subassembly for Equilibrium core. Equilibrium core is the state where fuel Subassemblies in the core have burnt for a definite period of time. The code calculates the individual subassembly outlet temperature according to flow and power fraction for that SA, Mean core outlet temperature and rise in mean core outlet temperature. At the time of flow blockage of a subassembly, the deviation in individual subassembly outlet temperature increases over its expected value and if it crosses its threshold, the SCRAM signal is initiated i.e. reactor comes to shutdown state automatically. The paper also discusses about the Integration of Core Temperature Monitoring logic model to the Simulator Environment and the integrated testing with simulator.

Novel approach of backplane communication for compact & field mountable I&C systems of FBR

This paper presents a novel and passive backplane communication protocol which can be used for CPU-I/O communication over backplane for I&C systems of a typical Nuclear Power Plant. This protocol is proposed as an alternate for existing protocols with essential features required for the development of reliable ultra-compact field mountable data acquisition & control systems. Customized serial communication on a non-shared bus is proposed with its benefits and limitations. Requirements for designing compact I&C systems is described with the possible approaches. The benefits achieved with this development are simple, reliable & easily verifiable interface logic on CPU/IO modules and reduced pin count backplane connector for IO modules leading to enhanced reliability. Remote Terminal Unit (RTU) design based on this developed protocol is detailed with the interface logic design, timings, electrical specifications, capabilities and connector/mechanical details. The concept validation on FPGA based hardware is also detailed.

Modelling and simulation of inclined fuel transfer machine in prototype fast breeder reactor operator training simulator

Indira Gandhi Centre for Atomic Research, Kalpakkam has successfully designed a 500 MWe prototype fast breeder reactor (PFBR). It is a proven fact that the critical factor in ensuring safe and reliable operation of any nuclear power plant is a qualified and well-trained personnel and hence, the need for operator training using a simulator. Fuel handling is one of the most important subsystems in a prototype fast breeder reactor. Ex-vessel subassembly transfer is done using an inclined fuel transfer machine (IFTM) which operates remotely and safely. Using IFTM, fresh fuel assemblies are loaded into the reactor, and spent fuel assemblies get unloaded. This paper deals with modelling and simulation of operations of IFTM in a simulator. Virtual panel models and control logic models were modelled using modelling tools present in the simulator. The process modelling was developed in-house using platform independent C++ code with 3D models.

Performance Comparison of Supervised Machine Learning Algorithms for Multiclass Transient Classification in a Nuclear Power Plant

For safety critical systems in nuclear power plant (NPP), accurate classification of multiclass transient leads to safer operation of the plant. Supervised machine learning is a key technique which solves multiclass classification related problems. The most widely used multiclass supervised machine learning methods for this purpose are k-nearest neighbor algorithm, support vector machine algorithm and artificial neural network (ANN) algorithm. This paper describes a comparative study on the performance of these algorithms towards classifying some of the transients in NPP. The performance analysis is mostly based on the prediction accuracy in classifying the correct transient occurred. Along with prediction accuracy, total number of epochs, training time and root mean square error was also observed as a characteristic feature for determining the performance of any backpropagation ANN. A 10-fold cross validation was carried on all these algorithms for ten times and the best among them was finally concluded for multiclass transient classification in NPP.

Process Modeling and Simulation of Feedwater Heaters Drains and Vents System of PFBR

Nuclear Power Plants are a complex system and need to be controlled very meticulously to avoid any catastrophe from occurring. The safety and availability of the power plant relies on the human operators both through their ability and reliability to ensure smooth and trouble-free plant operations. Training the operators on normal plant operation, maintenance, fault diagnosis and unforeseen emergencies in the plant helps reduce the latency period of the plant and thus increase the efficiency. Operator Training Simulator has become an indispensable entity in imparting hands on training to these operators. Development of process simulators calls for the process to be designed, modeled and implemented to replicate the real plant in steady state and transient conditions.

Simulation of control logics for plant transition state for PFBR Operator Training Simulator

In any nuclear power plant safety is assured by well defined procedures & practices and by implementing redundant & diverse technology. Procedures concern to the component/system will vary from state to state. Prototype Fast Breeder Reactor (PFBR) is a 500 MWe capacity, pool type reactor utilizing liquid sodium as a coolant and fuel as Mixed Oxide (Plutonium and Uranium). In general there are two reactor states inPFBR i.e. Transition state and Stable state. Wherein steady state indicates stable operating or shutdown state of reactor and transition state indicates an intermediate state between two stable states and this state ensures the healthiness of redundant/diverse system and its auxiliary system. This paper discusses about control logic simulation & implementation of Reactor Start-Up (RSU) system i.e. one of the transition state of PFBR which comes in-between Reactor in Shutdown (RSD) and Reactor in Operation (ROP). It elaborates about interfacing of various process conditions, authorization for reactor startup, inter connection of safety shutdown system, integration and testing of the simulated startup logic.