P. Swaminathan

Inner race bearing fault detection using Singular Spectrum Analysis

A novel method to diagnose the bearing fault is presented. The proposed method is based on the analysis of the bearing vibration signals using Singular Spectrum Analysis (SSA). SSA is a non-parametric technique of time series analysis that decomposes the acquired bearing vibration signals into an additive set of time series to extract information correlated with the condition of the bearing. Information in terms of time-domain features extracted from the SSA processed signal has been presented to a neural network for determination of inner race bearing fault. The result shows the effectiveness of the proposed method.

Accelerated life testing of Field Programmable Gate Arrays

Advent of VLSI technology has paved the way for Programmable Logic Devices (PLD), which are widely used as the basic building blocks in high integrity electronic systems. PLDs are considered for their robust features such as high gate density, performance, speed etc. For PFBR Instrumentation and Control systems, PLDs are extensively used to implement digital designs such as VME bus interface logic, control logic and sequencing logic etc. Types of PLDs, such as Field Programmable Gate Arrays, Complex Programmable Logic Devices and Gate Array Logic devices are used in Core Temperature Monitoring System and Safety logics of shutdown systems. Since these devices are reliable as per the manufacturers specification, they were used in R&D facilities like Fast Breeder Test Reactor and Augmented Boron Enrichment Plant as test beds.

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.

Reliability analysis of Safety Logic with Fine Impulse Test system of Indian Prototype Fast Breeder Reactor

Safety Logic (SL) System is a safety critical system provided to protect the Prototype Fast Breeder Reactor (PFBR) against various neutronic & thermal incidents. SL system receives trip parameters from various systems such as neutron flux monitoring, failed fuel detection, sodium flow monitoring, reactor inlet temperature monitoring etc and performs logical operations to drive Electro-Magnet (EM) coils of Control and Safety Rod Drive Mechanism which holds the absorber rods. Whenever any trip parameter exceeds / falls below the preset threshold or whenever important equipment / system is not available, SL system shuts down the reactor by dropping the absorber rods into the reactor core. The trip parameters are triplicated in nature, i.e. Triple Modular Redundancy (TMR) concept is employed.

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.

Formal representation of knowledge using Z in fast breeder test reactors

In this paper, knowledge representation using Z, a formal notation, is adapted in mapping Fast Breeder Test Reactor (FBTR) requirements. The most frequent cause of faults in safety-critical real-time computer systems is traced to fuzziness in representing requirements knowledge. Pitfalls using a natural language as a medium for representing the system requirements knowledge were analysed and explored. To ensure the specified safety, it is necessary to represent the system requirements of safety-critical real-time computer systems using formal mathematical methods. This removes the fuzziness in communicating knowledge on reactor system requirements. This paper contains the formal mathematical model for requirement specifications of FBTR systems using Z notation. Finally, the advantages of using formal representation for representing system requirements knowledge of FBTR using Z notations to minimise the ambiguity in knowledge communication and thus improve the safety are summarised.