A REPORT ON VOCATIONAL TRAININGNUCLEAR POWER CORPORATION OF INDIA LTD. (A Government of India Enterprise) Rajasthan Atomic Power Station DURING THE PERIOD FROM 11th JUNE 2012 SUBMITED TO: Mr. M. M. GUPTA TO 10th JULY 2012 SUBMITTED BY UMESH KUMAR MEHAR B.TECH. (III Year) BRANCH: - ECE SUBMITTED BY: - UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY,CHITTORGARH 1 PREFACE As we know that an engineer has to serve an industry, for that one must be aware of industrial environment, their management, problems and the way of working out their solutions at the industry. After the completion of the course an engineer must have knowledge of interrelation between the theory and the practical. For this, one must be familiar with the practical knowledge with theory aspects. To aware with practical knowledge the engineering courses provides a six weeks industrial training where we get the opportunity to get theory applying for running the various process and production in the industry. I have been lucky enough to get a chance for undergoing this training at RAJASTHAN ATOMIC POWER STATION. It is a constituent of board of NPCIL. This report has been prepared on the basis of knowledge acquired by me during my training period of 30 days at the plant. SUBMITTED BY: - UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY,CHITTORGARH 2 ACKNOWLEDGEMENT It at was highly educative and interactive to take training RAJASTHAN ATOMIC POWER STATION. As technical knowledge is incomplete without practical knowledge, I couldn’t find any place better than this to update myself. I am very much thankful to the Site director Mr. C.P. Jhamb &Training superintendent Mr. D. Chanda for allowing me for the industrial training at RAPS. Thanks to Mr. A.P. Jain for their guidance during my project. I also take the opportunity to thanks Nuclear training Centre for providing lecture on overview of the plant and providing me Orange qualification. SUBMITTED BY: - UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY,CHITTORGARH 3 INTRODUCTION India's Nuclear power developments are under the purview of the Nuclear Power Corporation of India, a government-owned entity under the Department of Atomic Energy India. The corporation is responsible for designing, constructing, and operating nuclear-power plants. In 1995 there were nine operational plants with a potential total capacity of 1,800 megawatts, about 3 percent of India's total power generation. There are two units each in Tarapur, north of Bombay in Maharashtra; in Rawatbhata in Rajasthan; in Kalpakkam near Madras in Tamil Nadu; and in Narora in Uttar Pradesh; and one unit in Kakrapur in southeastern Gujarat. However, of the nine plants, all have been faced with safety problems that have shut down reactors for periods ranging from months to years. The Rajasthan Atomic Power Station in Rawatbhata, India was closed indefinitely, as of February 1995. Moreover, environmental problems, caused by radiation leaks, have cropped up in communities near Rawatbhata. Other plants operate at only a fraction of their capacity, and some foreign experts consider them the most inefficient nuclear-power plants in the world. 4 SUBMITTED BY: - UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY,CHITTORGARH MISSION To develop nuclear power technology and produce in a self-reliant manner nuclear power as a safe, environmentally benign and an economically viable source of electrical energy to meet the growing electricity needs of the country ********** 5 SUBMITTED BY: - UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY,CHITTORGARH VISION NPCIL has its vision to have an installed nuclear power capacity of 20.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY. importing light water reactors and by the introduction of fast breeder reactors. This capacity could be achieved by the development of more 220 MW(e) & 550 MW(e) units of Pressurized heavy water reactors.CHITTORGARH . ************** 6 SUBMITTED BY: .000 MW(e) by the year 2020. UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY.7 SUBMITTED BY: .CHITTORGARH . UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY.Prime Minister DAE NPCIL TAPS 1&2 TAPP 3&4 RAPS 1& 2 RAPS 3 & 4 RAPP 5 & 6 MAPS NAPS KAPS KAIGA PS 1& 2 KAIGA Proj.CHITTORGARH . 3& 4 Atomic Energy Commission Atomic energy Regulatory board India Rare Earth BARC Heavy Water Board Indra Gandhi center for advance research Nuclear fuel complex KKPS ECIL Center for advance technology UCIL 8 SUBMITTED BY: . P.W. 9 SUBMITTED BY: . However. Ultimately water is turned into steam at high pressure that is used to derive turbines as in any conventional power plant. The maximum wind velocity records so far is 129 km/hr at 120 m. It however does have a population of about 58 thousand distributed in the radius of 15 Km. for slowing down the neutrons. The energy released is absorbed by the water (either light or heavy). The mass that is destroyed is converted into energy (200Mev/ fission). This process is called nuclear fission reaction. in a reactor. some of the neutrons produced are absorbed so that for every neutron causing fission. The plant site is about 64 KM from Kota city. above mean sea level with a latitude of 24053’ north and a longitude of 76036’ east. A neutron it splits into two big parts hits when a heavy nucleus likes that of uranium – 235 & in addition 2 or 3 neutrons are released. The fuel in a nuclear reactor consists of Uranium that may be natural or enriched in which proportion of U235 is increased. only one is left. This coolant in turn transfers its energy to the light water.P). the most predominant wind direction is at 7. the mass of the parts is slightly less than the mass of the uranium nucleus. India has six Nuclear Power Plants.CHITTORGARH .RAPS LOCATION AND SITE CONDITIONS RAPS is located on the eastern bank of Rana Pratap Sagar lake (R. This neutron in turn collides with another U235 nucleus & causes fission. Also.90m and 120m heights is North of south west and west of south west respectively. The place has an average rainfall of 825mm as per records. Two processes produce this: 1) Nuclear fission. It is much more likely if neutrons are slow.S dam across the chambal river at an elevation of 388 mt. the only nearby major industry is HEAVY WATER PLANT (H.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY.S) upstream of the R. A chain reaction is thus set up.P. 2) Nuclear fusion. NUCLEAR ENERGY: Mass defect converted into energy through nuclear reaction. the neutrons have to be slowed down. Either light water (for enriched uranium) or heavy water (for natural uranium) may be used as a moderator. The site has no population with in its vicinity of radius of 5km. SOME IMPORTANT NUCLEAR REACTIONS: 1) 92U238+0n1-----92U239+r------93Np239-------94Pu239 Typical fission reaction: 2) 92U235+0n1------38Sr90+54Xe144+20n1+r+200MeV Reactor poisoning reaction: 3) 52Te 135 ----53I135-----54Xe135-----55Cs135---56Ba135 (Stable) We know that about 200MeV of energy is released during per fission. 4) Energy of gamma rays released on n–capture: 10MeV. At Tarapur in Maharastra. At Narora in Uttar Pradesh At Kakarpara near Surat in Gujarat At Kaiga near Karwar in Karnataka. of the fission fragments: 167MeV. 6) Beta – decay energy: 5MeV. ---------------------------- 10 SUBMITTED BY: .CHITTORGARH .E. 3) Energy of gamma released at fission: 5MeV. Nuclear fission has become commercially viable and is being exploited in several countries. The reactors at Tarapur use enriched uranium as fuel & light water as moderator and coolant. At Rawatbhata near Kota in Rajasthan At Kalpakkam near Madras in Tamil Nadu. 2) K. ---------------------------TOTAL =199MeV. of neutrons: 5MeV.E.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY. 5) Gamma decay energy: 7MeV. all others use uranium and heavy water. This energy is divided in the following way: 1) K. Nuclear Power Plant under construction is two units of 500 MW at Tarapur and two similar units at Rawatbhata near Kota. This stage envisages on the construction of Fast breeder reactors (FBR) fuelled by plutonium & depleted U produced in stage I.Thorium as fuel. 3) STAGE III = This stage would comprise power reactors using U233. which is used as a blanket in these type of reactors. Spent fuel from these reactors is reprocessed to obtain plutonium. linking the fuel cycle of pressurized heavy water reactor (PHWR) & Fast breeder reactors (FBR) for judicious utilization of our reserves of Uranium & Thorium. as uranium enrichment is capital intensive. 11 SUBMITTED BY: . helps cut heavy investments on enrichments.This stage envisages construction of natural Uranium. The nuclear power programme formulated embarked on the three-stage nuclear power programme. The emphasis of the programme is self – reliance and thorium utilization as a long -term objective.THREE STAGES OF INDIAN NUCLEAR POWER PROGRAMME: 1) INTRODUCTION: India figured in the nuclear power map of the world in 1969. Heavy water moderator & cooled pressurized heavy water reactors (PHWR). The three stages of our Nuclear power programme are: 1) STAGE I:. largely to prove the techno-economic viability of nuclear power. 2) Uranium requirement is the lowest & plutonium production is the highest. Use of natural uranium available in India. These reactors would also breed U233 from thorium.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY.The main objective of setting these units was. when two boiling water reactors (BWRS) were commissioned at Tarapur (TAPS-1&2) these reactors were built on the turnkey basis .CHITTORGARH . The PHWR was chosen due to the following: 1) It uses natural uranium as fuel. 2) STAGE II: . steam generators. As a part of PHWR Programme (STAGE I) second nuclear power plant was taken up as a joint Indo-Canadian venture this plant was built at Rawatbhata (Rajasthan) two units laid a milestone in the history of India all the components were taken up in India and the import content reduced considerably. Canadians withdrew in 1974. environmental & seismic qualification of safety analysis. Supply of equipments of international nuclear standard was also a problem so momentous efforts were put into development of such manufacturing industries. To achieve self –sufficiency in this field in the long run.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY. preparation &development of validation of computer codes. the department of atomic energy established extensive research & development facilities covering diverse areas for supporting technology absorption. 2) CHALLENGES FACED: The industry was new to the manufacturing techniques & stringent quality requirements of the nuclear components like calandria. The requirement of convectional power plant equipment was of much larger capacity than those being manufactured in the country. Indian engineers did balance design & commissioning of the Unit 2.CHITTORGARH . 12 SUBMITTED BY: . etc. The long-term policy is based on recycling nuclear fuel and harnessing the available Thorium resources to meet country’s long-term energy demand and security. The short –term goal of the programme was to complement the generation of electricity at locations away from coalmines. from prospecting to mining to fabrication of fuel & zirconium alloy components. Moreover.3) The infrastructure available in the country is suitable for undertaking manufacture of the equipment. for manufacture of precision reactor components & production of heavy water were also set up. and heavy water pumps. Extensive R&D set up were established for metallurgical studies of both fresh as well as radioactive material. fuelling machine. non –destructive testing. end shield. Facilities. as appropriate to the conditions in India. repair &replacement using robotics & life extension programme of the operating reactors.e. improve availability requirement of in.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY. the concerted efforts put in by DAE. 3. ease of maintenance etc. spent fuel storage bay & other auxiliaries like heavy water upgrading. a number of significant design changes have been made progressively from the first unit at Rajasthan to the 500 MWe units.CHITTORGARH . 1000MWe light water reactors (LWR) UNITS & fast breeder reactors (FBR) units. together with Indian industries & institutions have led to development & full capabilities to design. 1000 MWe per year in the coming two five –year plans. have also been successfully developed. The lay out for a typical 13 SUBMITTED BY: . These design changes have been made from the consideration of currently prevailing safety criteria.. construction. . Such an arrangement retains independence for safe operation of each unit & simultaneously permits optimum use of space. The basic design of the 220/500MWe units in similar. finance & construction time. NPCIL plans to contribute about 10% of the total additional needs of power of about 10000MWe per year i. waste management facilities etc. operation & maintenance of nuclear power plant. The total installed capacity of nuclear generation would increase to more than 20000 MWe in year 2020 from the present level of 2720 MWe. however. To summaries. Today India is amongst the select band of few countries of the world that have developed such capabilities. Separate safety related systems & components are however provided for each unit. manufacturing of equipment.service inspection. sharing common facilities such as service building.Technologies for inspection of the reactor components. DESCRIPTION OF STANDARD INDIAN PHWR: 1) LAYOUT: The nuclear power stations in India are generally planed as two units modules. Status of nuclear power generation & future plans: The nuclear power programme in India up to year 2020 is based on installation of a series of 235 MWe &500Mwe pressurized heavy water reactor (PHWR) UNITS. its constituent units & NPCIL. seismicity. Sectional views of the reactor building are shown in figure 2 depicting general layout inside the reactor building. Other safety related building s &structures are also located as not to fall in the trajectory of missiles generated from the turbine.220MWe station as given in figure 1. contain the fuel & hot high – pressure heavy water coolant.End – shields are the integral parts of the calandria and are provided at each end of the calandria to attenuate the radiation emerging from the reactor. A typical pressure tube assembly is shown figure 4 . safety related electrical & control buildings and the two turbine buildings. Orienting turbine building radial to the reactor building provides protection from the effect of turbine missiles. arranged in a square lattice. active service building including spent fuel bay. Removable shield plugs fitted in the end fittings provide axial shielding to individual coolant channels. the Indian pressurized heavy water reactor is a pressure tube type reactor using heavy water moderator. 2) REACTOR: In concept. These pressure tubes. which permit their sliding. and form part of the vault enclosure at these openings. also refer as coolant channels.CHITTORGARH . permitting access to the fuelling machine vaults when the reactor is shutdown. The buildings and structures have also been physically separated on the basis of their seismic classification. The calandria is housed in a concrete vault. which is lined with zinc metallised carbon steel & filled with chemically treated demineralised light water for shielding purposes. The end shields are supported in openings vault wall. The reactor as shown in the cut away view in figure 3 consists primarily of calandria a horizontal cylindrical vessel. The end fittings are supported in the end shield lattice tubes through bearing. It is penetrated by a large number of zircaloy pressure tubes (306 for 235MWe reactor).UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY. The pressure tubes are attached to the alloy steel and fitting assemblies at either end by special role expended joints. 14 SUBMITTED BY: . shows two reactor building. heavy water coolant & natural uranium dioxide fuel. The trip signal actuates a combination of fast acting valves and causes poison to be injected simultaneously in 12 interstitial liquid poison tubes of calandria. The reactivity control devices are installed in the low. 1) Regulating rods 2) Shim rods 3) Adjuster rods for xenon override 4) Natural boron addition in the moderator to compensate for the excess reactivity in a fresh core &for absence of xenon after a long shutdown. which are filled with lithium penta borate solution under helium pressure.CHITTORGARH . The second shutdown system. 15 SUBMITTED BY: . instrumentations & triplicated control channels. fast acting & independent shutdown systems have been adopted.critical in less than 2 secs. viz. the PHWR’s do not need a large excess reactivity. Fail-safe features like gravity fall &spring assistance have been incorporated in design if mechanical shut off rods. which is also fast acting. The regulating systems are thus fully independent with its own power supplies. Correspondingly the devices required for control of reactivity in the core need not have large reactivity worth’s. This feature provides a high degree of assurance that plant transients requiring prompt shutdown of the reactor will be terminated safely. Furthermore. Cobalt & stainless steel absorber elements have been utilized in the reactivity control mechanisms. the relatively spacious core lattice of PHWR allows sufficient locations to obtain complete separation between control & protective functions. The primary shutdown system consists of 14 mechanical shut off rods of cadmium sandwiched in stainless steel &makes the reactor sub. Standard reactors designs are provided with four systems for reactivity control. For 220MWe standardized design. two diverse.3) REACTIVITY CONTROL MECHANISMS: Due to the use of natural uranium fuel & on-load refueling. comprises 12 liquid poison tubes.pressure moderator region & so they are not subjected to potentially severe hydraulic & thermal forces in the event of postulated accidents.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY. which circulates pressure coolant through the fuel channels to remove the heat generated in fuel. refueling to compensate for fuel depletion & for over all flux shaping to give optimum power distribution is carried out with the help of 2 fueling machines. which have very low excess reactivity. sheathed &sealed in thin zircaloy tubes. One of the machines is used to fuel the channel while the other one accepts the spent fuel bundles. opening & closing of the respective seal plugs. two reactor inlet headers. four pumps &interconnecting pipes & valves. In addition. sending spent fuel from magazine to shuttle transfer station. receiving new fuel in the magazine from fuel transfer system. from shuttle transfer station to inspection bay & from inspection bay to spent fuel storage bay. Figure 5 shows the 19. Each fuelling machine is mounted on a bridge & column assembly. is referred as Primary Heat Transport System.4) FUEL DESIGN: Fuel assemblies in the reactor are short length (half metre long) fuel bundles.element fuel bundle being used in 220 MWe PHWRs. Twelve of such bundles are located in each fuel channel. Various mechanisms have been provided which enables clamping of fueling machine head to the end fitting. the fueling machines facilitate removal of failed fuel bundles. Y&Z direction) of fueling machine head and make it possible to align it accurately with respect to channels. The major components of this system are the reactor fuel channels.directional movement (X. 6) PRIMARY HEAT TRANSPORT (PHT) SYSTEM: The system. feeders. In this type of reactor. The basic fuel material is in the form of natural uranium dioxide a pellet. 5) FUEL HANDLING: On –power fuelling is a feature of all PHWRs. The headers steam generators & pumps are 16 SUBMITTED BY: . Various mechanisms provided along tri. shield plugs &perform various fuelling operations i.CHITTORGARH . two reactor outlet headers. which work in conjunction with each other on the opposite ends of a channel.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY. Welding them to end plates to form fuel bundles assembles these tubes.e. The purification system consists of stainless steel Ion – Exchange Hoppers. The high chemical purity and low radioactivity level of the moderator are maintained through moderator purification system. 7) MODERATOR SYSTEM: The heavy water moderator is circulated through the calandria by aid of a low temperature & low – pressure moderator system. The cooled moderator is returned to the calandria via. Also.the coolant circulation is mentioned at all times during reactor operation.Exchange resin (80% anion & 20% cation resins) . mixed Ion . Figure 6 depicts schematically the relative layout of major equipment in one bank of the PHT system . Furthermore. in the core there would no significant increase in the reactivity.72% U-235) precludes the possibility of a reactivity accident during fuel handling or storage. This system circulates the moderator through two heat exchangers. high melting point of UO2 permits several full power 17 SUBMITTED BY: . The headers are connected to fuel channels through individual feeder pipes. which remove heat dissipated by high – energy neutrons during the process of moderation.located above the reactor and are arranged in two symmetrical banks at either end of the reactor.CHITTORGARH . 7) FUEL: The use of natural uranium dioxide fuel with its low content of fissile material (0.the purification system is also utilized for removable of chemical shim. shutdown & maintenance. in the ever of any mishaps causing redistribution of the fuel by lattice distortion or otherwise. Moderator inlet nozzles. boron to effect start –up of reactor Helium is used as a cover – gas over the heavy water in calandria.gas is control led by circulating it using a sealed blower and passing through the recombination containing catalyst Alumina – coated with 0. The thermal characteristics namely the low thermal conductivity and high specific heat oh UO2 permit almost all the heat generated in a fast power transient to be initially absorbed in the fuel.3% Palladium. eight numbers in 220MWe contains nuclear grade.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY. The concentration deuterium in this cover. Also on the account of the uranium dioxide being chemically inert to the water coolant medium. Most of the fission products remain bound in the UO2 matrix and may get released slowly only at temperatures considerably higher than the normal operating temperatures.CHITTORGARH .clad gap conductance resulting in lower fuel temperatures & consequently lower fission gas release from the UO2 matrix into pellet – clad gap. However the bulk of the heat is removed by End shield cooling system. Heat is removed from the end shields to moderator and calandria vault water. The use of 12 short length fuel bundles per channels in a PHWR. rather than full – length elements covering the whole length of the core. REACTOR AUXILIARIES END SHIELD COOLING SYSTEM There are two End Shields provided at both the ends of calandria performing the following functions.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY. The thin Zircalloy – 2/4 cladding used in fuel elements is designed to collapse under coolant pressure on to the fuel pellets. subdivides the escapable radioactive facility in PHWR has also the singular advantage of allowing the defected fuel to be replaced by fresh fuel at any time. This feature permits high pellet . (ii) Provides radiation and thermal shielding for fuelling machine vaults so that the fuelling machine vaults can be accessible during shutdown. 18 SUBMITTED BY: . the defected fuel releases limited amount of radioactivity to the primary coolant system. (i) Providing supports for calandria tubes and pressure tubes. The basic requirements of the end shield cooling system are: (i)To maintain calaridria side tube sheet (CSTS) of end shield at an average temperature of 67deg centigrade.seconds of heat to be safely absorbed above that contained at normal power. DM Water (900 LPM) enters the front compartment (the compartment facing the calandria) from five inlets at the top. circulating pumps. This heat is removed by __ circulation of demineralised water through the End Shields. A total of 1. Feeders. in end shield. convection and radiation across insulation gaps. (iv)To avoid overheating and hot spots which could lead to damage of end shield. and also acts as heat sink in case of serious contingency. and heat exchangers.4 MW of heat load exists for each end shield. (v)To provide venting of end shield for uniform shielding in accessible and S/D accessible areas. An auxiliary loop exists for the control of water chemistry. CALANDRIA VAULT COOLING SYSTEM In RAPS calandria vault (the space between the calandria and steel lined structural wall) is full of demineralised (DM) water. DM water filled calandria vault provides radiation.CHITTORGARH . The End Shields consist of two compartments called front and rear compartments.e. End fittings. The End Shield Cooling System is a closed loop system Consisting of end shields. biological and thermal shielding.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY. Filling of calandria vault with DM water eliminated Argon-41 activity of earlier Indian PHWRs which had air filled 19 SUBMITTED BY: .7 cm/sec and flows into the annulus space between the outer and inner shells of End shield. (Almost 50% of the heat load is from PHT). (iii) To avoid stagnant pockets of coolant. which could cause corrosion problems. There are two end shields where the heat is generated due to radiation and conduction from other reactors component i. DM Water passes through these columns at a velocity of 37.(ii)To maintain temperature difference between various parts of end shield within permissible limits. Front Compartment is further divided into five separate columns. This drastically cuts the exposure of public in the vicinity of Indian Nuclear Power Plants. is distributed through perforated header laid out in the bottom of the vault and warm water at 46. FUNCTIONS OF THE CALANDRIA VAULT COOLING SYSTEM i)To remove heat generated in vault water. VAPOUR SUPPRESSION SYSTEM Large pooi of water (2200M3.calandria vaults (RAPS 1&2 AND MAPS). iv) Provide an environment compatible with the material used for components within vault. Water at 42. ii)To provide thermal shielding and biological shield under all condition. Volume Vi is connected to the suppression pool via an annular space between the RB structure wall and inner containment wall. Heat appearing in calandria vault water is removed by a closed loop cooling system. iii) To maintain uniform temperature in the vault structure below permissible limit under all condition.4m deep) at the basement of the reactor building is provided to limit peak pressure inside volume Vi during LOCA (Loss of coolant accident) or MSLB(Main steam line break) by condensing high enthalpy steam. 2. 20 SUBMITTED BY: .5deg cen.CHITTORGARH .UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY. The dimensions of the calandria vault are such that a minimum water thickness of 1. leaves the vault through header at the top. The suppression pool is provided with a re circulation system to protect against corrosion and biological growth. This ensures adequate shielding.2deg cen.35 meters is ensured between the calandria and concrete vault. the annulus gas minimizes corrosion and hydrides formation in the coolant tubes or in the garter spring spacers by providing a dry 02 doped gas atmosphere in the annulus. LPIS is actuated so that sub criticality margin is maintained under all conditions. the annulus gas also acts as a thermal barrier. This causes the pressurisation of poison tank by helium stored in helium tank. In addition. This is an independent process system and is the replacement of (i) ALPAS bulk addition mode (at NAPP and KAPP) which required moderator circulation and (ii) gravity addition of boron (GRAB) The LPIS works on pneumatic pressurization of boron solution by helium. separating the hot high pressure coolant tubes and the comparatively cooler low pressure calandria tubes.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY.ANNULUS GAS MONITORING SYSTEM The annulus gas monitoring system of RAPP 3&4 provides a means of monitoring the leakage (if any) of heavy water either from PHT or from moderator system due to failure of coolant tube calandria tube or rolled joints. By reducing heat transfer between coolant tube and calandria tube. Apart from leak detection. heat removal requirements from moderator system are minimized as well as the reduction in loss of heat from PHT system. It is a closed loop recirculating system which maintains flow of C02 gas through the annulus gap between coolant tithe and calandria tithe. LPIS adds a bulk amount of liquid poison directly to the moderator to keep the reactor under shutdown state for prolonged duration. This in turn causes injection of 21 SUBMITTED BY: .CHITTORGARH . The system consists of poison tank and helium tank. When a command for poison addition is received the pressure balance valves and siphon break valves close and injection valves open. LIQUID POISON INJECTION SYSTEM For prolonged shutdown of reactor (1) for maintenance jobs or (ii) when reactor has tripped on reactivity transient which do not permit restart of reactor within poison override time. UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY. Products resulting from radiolytic process. Cleanup system comprises of oil water separation stage. To ensure personnel spray supply. Such leaked heavy water collected from various points in the reactor is to be upgraded before use in reactor.CHITTORGARH . D20 evaporation and cleanup system is designed to clean the downgraded heavy water chemically so that it can be fed to upgrading plant. To provide backup PW cooling to various systems. Fire protection system consists of fire fighting water system. 22 SUBMITTED BY: . FIRE FIGHTING SYSTEM Fire protection system in a nuclear power plant is meant To prevent damage to various equipment or system due to fire. it gets downgraded on exposure to atmosphere. carbon dioxide fire protection system and portable fire protection system. The heavy water collected from various leakages and spills contains a number of impurities which normally arise from— Surf ace from which D20 is collected. filtration stage and ion exchange stage. To ensure decay heat removal of the reactor. Corrosion products produced inside the reactor D20 system. Heavy water is highly hygroscopic. since the isotopic purity required for moderator heavy water is as maximum as achievable. To minimize the release of radioactivity to environment in the event of a fire. Organic material from ion exchange resin dueteration and breakdown. Hence it leaks from the system. HEAVY WATER UPGRADING SYSTEM Heavy water is used as moderator and primary heat transport fluids in PHWRs.boron poison directly into the moderator through two nozzles in calandria at 75%FT level D2O EVAPORATION AND CLE~AN UP SYSTEM D20 evaporation and clean up system purifies downgraded heavy water to a level which is not harmful to heavy water upgrading system by removing all the impurities. FIRE WATER SYSTEM Fire water system comprises of constantly pressurized fire hydrant system and sprinkler system. Class III power supply to all safety related electric motor driven equipment and backup supply from fire water system to meet static component failure This system is potentially active since there is a possibility of leakage of active primary fluid to this system through various heat exchangers. moderator system and reactor auxiliary system to ultimate heat sink during all operational stages of the plant and accident condition like LOCA. RB VENTILATION SYSTEM RB is designed as a double containment structure in order to prevent ground level release during accident conditions. dome region and includes FMSA when they are in contact with F/M 23 SUBMITTED BY: . Hydrant system covers the whole plant for outdoor and indoor supply of firewater. Primary containment houses all equipments and piping of nuclear systems.CHITTORGARH . Vi containing the systems having high enthalpy fluids comprising of F/M vaults. PC is divided into two volumes. ACTIVE PROCESS WATER SYSTEM Active process water system provides direct means of heat transport from equipment and heat exchangers in the primary heat transport system. Thus it forms the secondary part in the ultimate heat removal system. Reliability and continuous heat removal is achieved by designing the system for SSE/OBE by providing redundancy in rotating equipment. Secondary containment envelops the primary containment with an annular radial gap of 2 meters. Water for both hydrant and sprinkler system is supplied by the firewater pumps from the sumps located in the cooling water pump house(CWPH). pump room. Automatic sprinklers have been provided for oil filled transformers and non-automatic sprinklers are provided for oil systems.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY. It is a safety-related system. cable vaults and cable tunnels. The volume Vi is maintained at negative pressure with respect to V2 by maintaining continuously a small purge to the stack. To keep the volume Vi area under negative pressure with respect to volume V2 area for preventing the spread of activity from volume Vi to volume V2. Following are the criteria for design and operation of vapour recovery system— To effect economy in reactor operating costs by efficient recovery of heavy water that escapes into the building atmosphere.CHITTORGARH . Vapour recovery system is an important feature of the station heavy water management schemes.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY. The remaining area constitutes volume V2. FMSA and DN monitoring rooms. No ventilation is provided for this volume but closed loop heavy water vapour recovery system is provided to recover D20 that escapes from high enthalpy systems. The calandria is a single walled austenitic stainless steel vessel.vaults. The main shell is stepped down in diameter at each end and 24 SUBMITTED BY: . These areas are not accessible during normal plant operation. moderator and fuelling machine circuits is recovered from building atmosphere by adsorption on molecular sieve beds. CALANDRIA The calandria is horizontal vessel housed in a rectangular calandria vault. Volume V2 is separated from Vi by a leak tight barrier and pressure suppression pool. Volume V2 is normally accessible except moderator room. HEAVY WATER VAPOUR RECOVERY SYSTEM Heavy water vapour arising out of spills/leakages from primary heat transport. To minimise heavy water loss and tritium loss and tritium release through stack. To minimise tritium activity levels in various areas of the reactor building. Each end of the coolant tube is joined to a special type 403SS end 25 SUBMITTED BY: . COOLANT TUBE Coolant tube is the most important structural component inside the reactor core. 2. CALANDRIA TUBE The calandria tubes are manufactured from Zircalloy2 strip that is cylindrically formed and seam welded.To separate the relatively cold moderator from hot coolant tubes to minimize heat losses. END SHIELD The end shields are cylindrical boxes whose extensions are welded to the calandria side tube sheet at the calandria end and fueling machine side tube sheets at fueling machine end of the end shield during shop fabrication.CHITTORGARH . The primary functions of the calandria tubes in a reactor system are1.To support the horizontal coolant tubes (through garter springs) and prevent the excessive sag caused by creep.site welded to their cylindrical extensions of the end shields on each side of the reactor. The seams are then leveled by rolling.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY. Coolant tubes are manufactured from Zr-Nb. To act as containment vessel for the contents of the channel in the unlikely but postulated instance of a pressure (coolant) tube rupture accident. The space inside the end shield is divided into two compartments by a 38mm thick baffle plate and fueling machine side tube sheet is filled with 10mm dia spherical mild steel balls and light water in the 57:43 ratio.6mm square pitch. The box is pierced by 306 lattice tubes arranged on 228. SEAL PLUG The function of the sealing plug is to close the ends of the coolant assemblies and prevent the escape of heavy water from the end fittings. with a single thrust bearing on HP shaft between No. with special provision for extraction of moisture. of parallel coolant tubes are placed horizontally inside the reactor core at the square lattice distance of 228. The turbine cylinders and generator is solidly coupled together in line. The nozzle plates of the HP 26 SUBMITTED BY: . Coupling each rotor is supported in two main bearing. A solid forged steel rotor is provided in the HP cylinder whilst the LP rotor have shrunk and keyed on discs. GARTER SPRING SPACERS Four numbers of garter spring for each coolant channel and located in the annulus space between coolant and calandria tubes. reheating. END FITTINGS The end fittings on either end of the reactor identical and connected at the ends. The turbine is of the horizontal tandem compound.CHITTORGARH . Such 306 Nos. SHIELD PLUG The shield plug which normally resides in the end fitting serves the three functions of providing — Radiation shielding at the ends of the coolant tubes Means of locating the fuel in the fuel channel and stopping the fuel column from following the seal plugs when they are withdrawn during fuel changes.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY. 2 bearing (HP rotor bearing) and the HP~LP. running at 3000 rpm. The turbine comprises of one HP cylinder and two double flow LP Cylinders thus providing 4 LP flow in parallel. 6mm.fitting. The turbine has a maximum continuous and economic rating of 220 MW. impulse type. Thetas are five impulse stages in the HP cylinder and six stages for each of the LP cylinders. During fuel changes it is necessary to remove these plugs. Steam is extracted from double flow L1~ cylinder before stages 24 and b for feed heating and before stage 6 for a moisture extractor.5 psig and temperature of 43OoF passes through governor operated butterfly interceptor valves before entering the two double flow LP cylinders. The LP cylinder of turbine is of four flow design: each two flow LP has a central admission belt with outward direction of steam flows. and ensure that no excessive thrust loads from the piping are transmitted to the HP cylinder.E.60F (saturated) is supplied to the HP cylinder of the turbine through two separately anchored steam chests each containing a steam strainer a combined stop and emergency valve and two throttle (or governing) valves. which is maintained at vacuum 27.the exhausts from the LP bleeding combines into a condenser. During normal operation the C~S.5” hg. The chests are connected to the HP cylinder through loop at allow axial movement of this Cylinder.E. Extraction steam is taken for feed heating purpose before stages 4&5 and at the exhaust of the H. Steam is supplied to the two flow provision via the separator and reheater in each HP cylinder . The steam from the reheaters Having a pressure of 47. STEAM CYCLE: Steam for the turbine through two steam lines or header to the two stem lines or header to the two combined stop and emergency valves.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY.S. A10” balance line connected line connect the header the C.P cylinder after expansion is led two moisture separators in parallel which reduce the moisture content of the steam before it is reheating is two live steam reheaters. A data logger monitors all turbine and ancillaries parameter. valves are fully 27 SUBMITTED BY: . The over all length of the Turbine generators 100 and the outside diameter of the last row of blade is 100”. The LP diaphragms are cast iron with cast-in nozzle division plates. valves.cylinder are welded assemblies incorporating machined nozzle segments.CHITTORGARH . Steams packed labyrinth glands are provided for each cylinder. Live steam at a pressure of 580 psig and temp 482. An interceptor’s valve is provided in the line from each reheater to the LP inlets. P. the steam leaves the H~P. steam is bled off or Extracted and passed to feed water heat exchangers. Governor valve position controls turbine speed and load and thus are made responsive to the governor valves (two on each bank) are connected by means of balance lines and the steam passes to the H. After expansion. remaining extraction line and heater was calculated to give only a small increase so check valves were omitted 28 SUBMITTED BY: . one is an increase in the heat cycle efficiency and the minimum permissible inlet feed temp. The interceptor valves remain full open normal operation and admit the steam to LP cylinder from where it is exhausted to the condenser.. The to governor valves in each steam chest are in parallel i.P. Entrained steam from the (one.P. and are called lob pressure heaters if they are in the feed line before the boiler feed pumps and are called high pressure if they are in the feed line after the pumps.P.e. before entering LP cylinders. cylinder. LP emergency stops valves and interceptor valves. inlet nozzles. there is common inlet and outlet manifold for both of the two governor valves in a steam chest. These check valves close on a turbine trip to prevent entrained stream in the extraction lines and heaters from backing up into the turbine and causing it to over speed. trough the H. to boiler is 24OoF. Heating the feed water by extraction steam has two beneficial results. The RAPS turbine has six extractions feed heaters three including deaerators heaters Fed from the H. not all of the steam to the LP cylinders from where it is exhausted to condenser.CHITTORGARH . In the event of governor or interceptor valve malfunction the relief valve will open and vent the steam to atmosphere preventing over pressurizing the separator or reheaters. cylinder. cylinder and passes through the separator. cylinder. Also to relief valves are installed after each of the two re heaters.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY. cylinder This arrangement in conjunction with the 10” balance line ensures uniform steam take off from each of the 8 boiler and uniform distribution to each portion of H~P. reheater. Also lines from each steam chest joint and go to both top and bottom of H. Five of the extraction lines have spring closed check valves.open to permit steam flow to inlet steam chest and then to the two governor valves. Not all of the steam admitted to turbine by the governor valves is expanded through the turbine and exhausted to main condenser At different points on the turbine. This take off is located downstream of the condenser. 2 moisture Extractor.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY. The condensing system is provided to supply condensate from the deaerators under all condition of operation. One 21/2% capacity auxiliary condensate Extraction pump takes water from the condenser hot well and discharge into the same system as the 100% pumps. are 91 5oF in the condenser hot well and 245oF at the deaerators inlet DESCRIPTION Condensate system comprises of main condenser two 100% capacity condensate extraction pumps and two 21/4% duty emergency pump. pipelines and instrumentation The condensate extraction pumps take suction from the condenser hot well and discharge through the moisture extractors. The maximum flow of condensate to deaerators at 100% turbine load is i 900. the design temp. drain cooler and LP heaters. A condensate recirculation line back to the condenser is provided. the condensate flow is controlled by the control valve part of the Condensate front the condensate pump discharge header flow changes the gland steam condenser and air ejectors and returns to main condensate line before it enters the moisture extractors. The condensate pumps also supply boiler feed pump gland seal water and water f or the turbine spray cooling. The air gases are removed from the condensate by the air ejectors.000lbs/hr. gland steam and high level reserve feed water tank with their associate fittings. The flow in this line is controlled by means of regulating control valve which maintains a fixed differential pressure across the gland steam condenser having been designed to have the same pressure deferential tar its design flow as the air ejector.CHITTORGARH . 29 SUBMITTED BY: . The circulating water in the condenser condenses the exhaust steam from LP Turbines.CONDENSING SYSTEM: GENERAL. The condensate is recycled through boilers. g) All the supplies /services (electric. it is required to grade various systems. commensurate with their importance to safety.SAFETY DESIGN PRINCIPALS It has been ensured that systems. b) The safety related equipment inside the containment building is designed to perform its function even under the elevated pressure & temperature &steam environment conditions expected in the event of postulated loss of coolant accidents (LOCA).CHITTORGARH . e) To minimize the probability of unsafe failures f) Provisions are incorporated to ensure that active components in the safety systems are testable periodically. SAFETY CLASS I: It is the highest safety class & includes equipment & structures needed to accomplish safety functions necessary to prevent release of substantial core fission product 30 SUBMITTED BY: . compressed air or water) to these systems. necessary for the performance of their safety functions are assured & ‘safety grade’ sources. These requirements are met by adopting the following design principles: a) The quality requirements for design.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY. equipment & structures in their importance to safety & reliability. SAFETY & SEISMIC CLASSIFICATION OF SYSTEMS: SAFETY CALSSIFICATION: In the design of Indian PHWRs. components & structures having a bearing on reactor safety are designed to meet stringent performance & reliability requirements. d) Adequate redundancy is provided in systems such that the minimum safety functions can be performed even in the event of single active components in the system. The safety gradation consists of four different safety classes depending upon the nature of safety functions to be performed by the various items of the plant. c) Physical & functional separation is assured between process systems & safety systems. construction & inspection for these systems are of the high order. fabrication. CHITTORGARH . SAFETY CLASS III: Includes systems that perform functions. emergency core cooling system. which do not fall within the above classes but are required to limit the discharge of radioactive material & airborne radioactivity below the prescribed limits . dueteration &service building ventilation systems are classified as class IV safety systems. air supply system. are included in this category. which are needed to support the safety functions of safety class II & I. SAFETY CLASS IV: Includes those items & systems.inventory. it includes systems & functions required to control the release of radioactivity from sources located outside the reactor building. 31 SUBMITTED BY: . which become necessary to mitigate the consequences of an accident involving release of substantial core fission product inventory from fuel. which are required to prevent escalation of anticipated operational occurrences to accident conditions. SAFETY CLASS II: Includes equipment. This includes reactor shutdown systems & primary heat transport system.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY. reactivity control provisions & reactor containment building are included in this class. which performs those safety functions. shield cooling system primary coolant purification ion exchange columns & filters etc. waste management. Process watercooling system include induced draft cooling towers. Boiler feed water & steam system. This class also includes those items.D2O upgrading. Also. CHITTORGARH .UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY.32 SUBMITTED BY: . . 10 of the Display Stations are Utility CRTs (UCRTs) and the remaining 2 are Alarm CRTs (ACRTs). A three-tier system design consisting of Display Stations. They do the logging of the history data and take care of the printer tasks. trend curves. A high speed Ethernet LAN (Local Area Network) is used for communication between the subsystems. and pass the required data to display stations. I/O subsystems are Motorola 68020 CPU based systems.1.CHITTORGARH . They also direct the I/O systems to govern the field outputs as required. This makes the different subsystems to be hardware independent on each other. These systems are having high resolution (Super VGA-1024 x 768 pixels) 19” monitors.2 as the Operating system. Each I/O subsystem has 2 CPUs working in dual redundant mode. DPHS. Data Acquisition Computers and I/O subsystem has been adopted to improve the reliability and availability. which give a good pictorial representation of the data. status. They are Intel 80386 microprocessor based systems doing most of the user interface job. They mainly acquire the data from I/O subsystems and other Computer Systems like PLC. Both the DACs work in dual redundant hot standby mode. Data Acquisition Computers are based on Intel Pentium which UNIX SVR 4. RADAS etc.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY. They also do the network management of both the LANs. history displays and printouts of groups of process variables etc. They mainly do the scanning and alarm checking of the field inputs 33 SUBMITTED BY: .0 DESIGN DESCRIPTION: COIS is a data acquisition and display equipment for providing the operator with process alarm messages. A significant component in the topology is “Repeater”. c).UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY. which facilitate the connection without a cut in the cable. c or d fails than ¼ of inputs/outputs (of the nodes connected to that part of the network) will be lost & the system will continue to 34 SUBMITTED BY: . The network topology is designed in such a way that a single break anywhere in the network (broken cable or failed n/w equipment) will not result in a collapse of the total system.a. If any transceiver or the cable connecting the transceiver to the node fails. b). the hot standby DAC will take over and the system will not be affected. only that node will fail & reset of the system will continue to work as usual. They also change the field outputs as per the directive from DACs. This has given rise to a fault tolerant network. ii). The significant aspects of the designed network topology are: a). . If any one of the cables of LAN1 . If the connection with the Master DAC fails. b. It isolates the remaining network from a fault in any of the other cables. Repeater is an active component that can be used to connect different cables of networks.connected to them and pass on the data to DACs. Thicknet cable is used as it is much more rugged than the Transceivers that are used to connect different nodes to the network are piercing type tap boxes. The various failures considered their effect is described below: i).CHITTORGARH thinnet cable. but will allow the system to continue to work at a degraded level. The network is divided into 4 parts each connecting ¼ of the system. c or d fails.work with 75% of inputs/outputs data.CHITTORGARH . Analog inputs There are 1256 analog inputs to the COIS. These include about 10% spare points. 1. then ¼ of display stations will not be available. Display stations are connected in these four cables in such a way that CRTs on adjacent Main Control Room panels are connected to different cables and will not fail simultaneously. If more than one cable fails. COIS will still work with the corresponding reduction in display stations. If any one of the cables of LAN-2 – a. The approximate distribution into different categories is as follows: RTD’S Thermocouples Volts/Current Inputs Thermistor 392 points 16 points 824 points 8 points 35 SUBMITTED BY: . If more than one cables fail.1 Inputs/Outputs There are various types of plant inputs to the COIS viz. COIS still will work with the reduced capacity accordingly. iii). analog inputs and digital inputs. Each plant input is also referred to as “point” the COIS also provides voltage free relay contacts as outputs.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY. ACRTs are connected to different repeaters and hence will not fail simultaneously. b. for each analog input are available in the COIS analog input. Among the 824 voltage or current inputs.CHITTORGARH . For the current inputs the terminating resistors (of value as specified in analog input list) are a part of the COIS.Exact details of description. will be performed by the COIS.1. These analog inputs are numbered in the range of 000 to 1299.1. Cold junction compensation for thermocouple will also be provided by the COIS.. input range.1.g.1 Voltage free contact inputs: There are 736 voltage free contact inputs. Input impedance of voltage inputs is greater than 1 Ohm. There are two types of contact inputs as follows: 1. These contacts represent alarm or status inputs. any number may be voltage input. Linearisation and lead resistance compensation wherever necessary. 1. Provision will be made to terminate a 3 wire RTD at each RTD input point. 36 SUBMITTED BY: . for RTD and thermocouple inputs. Provision will be use 3 wire RTDs in the field. alarm priority. All RTD inputs will use 3 wire RTDs in the field. Thus all of these 824 inputs can be arranged to take a current or voltage input.1 Digital (contact) Inputs There are 1136 digital inputs of contact type.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY. e. process range and processing required etc. 1. Radiation Data Acquisition System (RADAS). 1.1.1. Digital Recording System (DRS). These contacts represent alarm events. The input impedance presented by COIS to these inputs will not be & 5901 to 5999 : 2801 to 2899 : 2901 to 2999 : 9501 to 3499 37 . 1.2 Digital (Voltage level) Inputs There are 656 voltage level inputs representing the status of valves (open or closed).1. Electrical DAS and PLC’s via LAN thorough gateways.2 Shared contact inputs: There are 400 field contact inputs which are shared between the window Annunication system (WAS) and the COIS.3 Input Data from other computer systems COIS receives data from other computers viz. In the COIS.1. State Level 0 Level 1 less than 10K ohm.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY. these input parameters are numbered as follows: (1) Radiation Data Acquisition System: Analog points: 3601 to 3799 Digital points: 3001 to 3999 (2) Electrical DAS: Analog & contact points: 7001 to 9499 (3) PLC’s Digital points representating : 1301 to 1999 Status of hand switch position (4)Digital Recording System (DRS) a) Normal/Disturbance Analog inputs b) Visicorder Function Analog inputs c) Contact inputs of ESR function SUBMITTED BY: .CHITTORGARH Voltage Between 0 volts and 2 volts Between 40 volts and 48 volts. Ten or these contacts are used for Fuel Failure Monitoring function described in Sec. Values of these points are provided to the COIS periodically by the above systems.g. these points are treated as the field COIS inputs.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY. 38 SUBMITTED BY: . The remaining contacts will be used for miscellaneous purposes like giving time synchronizing pulses to other computer based systems. selected channel differential temperatures and DNM detector outputs etc.1. for e.CHITTORGARH . 1. indication of which computer system is faulty etc.11. testing function described in section 5.6 The COIS will also provide.1. annunciation of the failure of the COIS.5 Ethernet The COIS will provide Ethernet LAN connectivity for connection to other computer systems.4 The COIS will also provide 224 outputs of voltage free relay contacts.d) Dual Process Hot Standby Analog inputs : 9501 to 9699 (5)Other Computer Systems a) Analog inputs b) Contact/digital inputs : 9701 to 9899 : 9901 to 9999 Note: There are no physical inputs corresponding to these points. These variables will be numbered in the range of 6001 to 6699.1. For all displays and logging functions except alarm functions. 1. on operator’s demand. 1. processed data outputs called calculated analog variables. 50Hz common mode voltage on any thermocouple inputs.CHITTORGARH .2 Overall accuracy of analog data acquisition for any point will be 0.c.1. common mode voltage.2 Accuracy.1 For all digital and analog inputs. 1. common mode voltage of + 15V d. Noise Rejection.c. Beyond 15V./a.c.25% of span or better.c. opto-isolators are used for digital inputs.2.c. /a. For providing the above common mode voltage capabilities.c. common mode or + 50V dc/ac normal mode voltage on any other type of analog inputs.c. + 250V d. protection is provided for a max./a. A low pass filter will be provided on each analog input to suppress normal mode (predominantly) 50Hz. on any input.c. Protection will be provided against following conditions for different categories of analog input. on the input./50Hz a.c. This accuracy will be maintained even in the presence of common mode noise (Max./50Hz. 1.240V AC (Max. 1. a very high isolation between the transducer circuit and the COIS is provided to avoid problems in the transducer circuit due to ground faults etc.+ 250V d.). noise. (Whichever is more) common mode or normal mode voltage. 39 SUBMITTED BY: .) + 15V d.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY. Contact Debounce and Isolation.3 Processing of potential free contact type inputs will not be affected even under a max.2. For RTD inputs: Depending on RTD bridge excitation network Or + 50V d.2. This adjustable could be on an individual basis or on group basis (Group = type of input). these points are not displayed on the ACRTs when the status of these points changes. five samples will be taken within the sampling interval and the average of these five samples will be taken as the value for that sampling interval. The remaining points will be checked 40 SUBMITTED BY: .3 Alarm Function The computer system will check some of the analog inputs and almost all of 736 digital alarm inputs in the 656 Digital (voltage) inputs for alarm events. Some COIS points are inhibited from reporting to ACRTs as alarms. Note: Sampling interval for all analog & contact inputs will be adjustable to any of the following: 5 sec. There will also be a provision for averaging over last five sampling intervals for selected number of analog inputs (max.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY.e.). and are not checked for alarm at all. 30 sec. Many analog points are only for periodic logging and BG display etc. 1.2. i. both alarms are not required.1... with the normal interval specified in the above table.CHITTORGARH . These average values will be used in all displays and printouts. But this does not prevent them from displaying their status in BGs.e. And some points have to be checked for only low alarm limit or only high alarm limit i. For all analog inputs. And some points have to be checked for alarm at all. Some of contact (digital) inputs are for status monitoring only and will not be checked for alarm. tabular trends etc. The remaining point will have both low and high alarm limits. 100Nos. 10 sec.4 In case of digital (contact) inputs and digital (voltage level) inputs input status changes lasting less than 50 milliseconds will be ignored by the system. This is also referred to as ‘Normal’ occurrence is short. BL (Bad Low) than lower end of span Lost. “High” and “Bad” states. A suitable audiovisual indication for the alarm in the concealed pages is provided. 2. Provision will also be made to list the alarms on any UCRT for a selected USI or a range of USIs keyed in by the 41 SUBMITTED BY: . Capacity for such 100 additional alarms is provided.CHITTORGARH . Latest ‘alarm/’ return to normal’ message line will also be displayed on the last line of all the ACRT pages. The frequency of alarm checking will be same as that or the point for data acquisition. An analog input going above a high limit (HL) or falling below a low limit (LL) or a digital input sent to alarm state since previous scan is referred to as an “Alarm” occurrence. analog points will be limited to only “low”. Analog input returning between its high and low point or a digital input going to normal state since previous scan is referred to as “return to normal” occurrence. As for as ACRT display or output on alarm printer are concerned. The alarm events are defined as follows: 1. Operator will be able to call up for display any of the ACRT concealed alarm pages on any of the two ACRTs or on both ACRTs will be different and independent. Such additional alarms will store in the computer memory and arranged as CRT concealed alarm pages for display purposes. Provision will be made for scrolling up or down (one line at a time) of ACRT display.for alarms. Provision will be made so that the operator can retain on the screen the most important/of immediate interest/relevant alarms only on the screen and put the rest of them in concealed alarm pages.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY. Such ‘ignored’ inputs will be resumed automatically in 30 minutes or whenever desired by the operator. The system will maintain a list of such “alarm-disabled points. 2) Mode 2: Under this mode. whichever is earlier. It will be possible to add/delete points in this “disabled list”.CHITTORGARH . It will be possible for the operator to call up the summary of existing alarms on any UCRT. It will also be possible to call this summary as total or only of alarms with a priority 1 or only of alarms with a priority 2. Provision will be made to list all alarms for a selected USI or range of USIs keyed in by the operator. This is called “alarm” display management”. Such operator commands will get immediately logged on Alarm Printer. repetitive alarms are also reported (without any suppression) lost. A suitable audiovisual indication for the alarm in the concealed pages is provided. Each input point will be given a priority number of 1 or 2. Provision will be made for scrolling up or down (one line at a time) of 42 SUBMITTED BY: . 1) Mode 1: Under this mode repetitive alarms are suppressed.e. approx.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY. as if those do not exist) for alarm function. Operator will be able to call up for display any of the ACRTs or on both ACRTs i. The COIS will have the following two codes of alarm processing. 5 concealed alarm pages) is provided. Such additional alarms will be stored in the computer memory and arranged as CRT concealed alarm pages for display purposes.e. Capacity for such 100 additional alarms (i. Inputs with priority of 2. Operator will be able to ‘tell’ the COIS any analog/digital inputs which are to be ignored (i. the pages selection keys for both the ACRTs will be different and independent.e.operator. Such ‘ignored’ inputs will be resumed automatically in 30 minutes or whenever desired by the operator. Inputs with priority 1 being more important than those with a priority of 2. i) ii) Mode 1: Under this mode repetitive alarms are suppressed. Each input point will be given a priority number of 1 or 2. as if those do not exist) for alarm function. It will be existing alarms on any UCRT.ACRT display. whichever is earlier. It will also be possible to call this summary as total or only of alarms with a priority 1 or only of alarms with a priority 2.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY. This is called “alarm display management”. Mode 2: Under this mode. Such operator commands will get immediately logged on Alarm Printer. 1) Alarm processing under mode 1: 43 SUBMITTED BY: . Provision will be made to list all alarms for a selected USI or range of USIs keyed in by the operator. Latest ‘alarm/’ return to normal’ message line will also be displayed on the last line of all the ACRT pages. The system will maintain a list of such “alarm-disabled points. It will be possible to add/delete points in the “disabled list”. Provision will also be made to list the alarms on any UCRT for a selected USI or a range of USIs keyed in by the operator. Provision will be made so that the operator can retain on the screen the most important/of immediate interest/relevant alarms only on the screen and put the rest of them in concealed alarm pages. The operator through a password can select alarm-processing mode 1 or 2.e. Operator will be able to ‘tell’ the COIS any analog/digital inputs which are to be ignored (i. repetitive alarms are also reported (without any suppression).CHITTORGARH . Of alarm generation will be programmable between ¼ of an hour to a selected period will also be adjustable between 4 and 10. Any point which changes status (from normal to alarm/bad or alarm/bad to normal etc.1 There are about 400 Nos. some of the points (analog/contact) may oscillate between alarm and normal states and hence any cause large number of alarm/normal messages on the alarm printer & ACRT’s. 1. Hence. will be automatically disabled from alarm scanning for the remaining part of the quarter hour. every quarter of an hour. This period for checking max. if 6th message is normal message. (Note: These are the window 44 SUBMITTED BY: . Is not required for these).e. Tape cartridge/disk cartridge (i. Alarm message) is reported.Under some abnormal field conditions. For this purpose.CHITTORGARH .e. CRT display and audio ann. it is required that not more than six message (status changes) are generated by any point in any quarter of an hour. the COIS will set the “status change” count of each to zero.) 6 times in any quarter of the hour. NO. the COIS will disable alarm scanning of the point after 7th message (i. digital inputs (shared input contacts) which are scanned only for the logging of their status changes on the alarm printer and mag.e. But the COIS will freeze the status only with alarm/bad status i. Alarm processing under mode 2 : All alarm messages are reported without any suppression.3.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY. first alarm message in red colour. 1. otherwise it is 45 SUBMITTED BY: .3 Valve Status Monitoring There are 656 Nos. Voltage level inputs are normally taken across the indicating lamps corresponding to the valve. Status changes are recorded on magnetic tape also. These are voltage level inputs with two levels. 1. These are scanned every one second. When the indicating lamp is ‘ON’ indicating valve “Fully open” or “fully closed”. at 0 volt for 48 volts dc. successive alarm message will be displayed in alternate red and pink colours on UCRTs (e.3. Normal message will always be shown in green colour. These inputs are scanned once every 1-second for displaying the actual status of the valves in the Mimics and for logging their status changes on printer used for alarm logging.e. However.annunciator points numbered in the range of 4001 to 4999). Each valve to be monitored for its status on COIS will have one or two inputs connected to COIS.3.CHITTORGARH . voltage level inputs representing the valve status (open or closed). Any alarm/normal message will be continuously displayed until another alarm/normal message is generated to replace the previous one.2 Latest Alarm Message Display Function on UCRTs The latest “Alarm”/”Normal” message displayed on the ACRTs will also be displayed on the bottom-most line of all the UCRTs also. i.g. Operator will provide a facility to switch off this alarm/normal message display on any UCRT whenever required.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY. second in pink colour and third in red again and so on). No flashing of the alarm message or any audio is required on the UCRTs. the input to COIS is +48V DC. For valves having single input to COIS. the status will be either “Fully open” or Not Fully open” (“Not Fully Closed”). The “Instrument failure” status is treated as an alarm and would be annunciated on the ACRT. It may be noted that the “Intermediate” status and “Instrument failure” status are taken as new status only if it has remained so for two successive scans.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY. FAILURE The COIS will show the actual status in the Mimics appropriately.4 Interface to Various other Computer Based Systems The COIS will also provide Ethernet LAN interface for connecting the following computer systems. the COIS will sense both the inputs and derive the status as follows: “Fully open” input 48 V 0V 0V 48 V “Fully Closed” 0V 48 V 0V 48 V Input Status Fully open Fully closed In intermediate position INST.CHITTORGARH . The COIS will receive data from them as required as per the approved protocol. If there are tow inputs corresponding to a valve. The data will be available for all the functions described in this design manual except for alarm function: a) RADAS 46 SUBMITTED BY: .zero. If there is a change in status the new status will be logged on to the printer. It will also log the change of status on the printer accordingly. 1. ‘Help’ facility will be available at all phases of dialogue. it will be showing the main menu. The COIS will be user friendly and the operator will be able to get the desired information in desired formats on the various UCRT’s in an interactive manner. Various menus/indexes/lists of UCRT’s functions. will not call for entry of artificial low/high alarm limit e. History groups and graphic trend groups etc. If no display is demanded.g. BG’s. No UCRT will have a blank screen at any time. will be displayed on the UCRT on operator’s demand. Data retrieval procedures will be quick and easy. as this 47 SUBMITTED BY: .b) c) d) e) f) g) Electrical SCADA (EDAS). Process data base will contain flags for each Analog input to indicate whether any Low Alarm Limit/High Alarm Limit is applicable or not.5 General Features: 1. lower than lower end of span/higher than higher end of span etc. 2. Menu driven CRT based dialogue with the system will be designed. 1. Software for Alarm processing and various displays etc. PLC DRS DPHS CTM PDCS etc.CHITTORGARH . so that operator can quickly select the display of his choice.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY. ) will in various cases be as follows or better: Sr.3245 for a process range of 0-100°C will be avoided and an approximated value 21. Analog inputs cards are designed for automatic calibration at regular intervals under software control using precision reference sources for 25% and 75% scale.1 to 0. 4.3 will be displayed.1% 0.CHITTORGARH . etc. 48 SUBMITTED BY: . The operator will not require a better resolution than this and it will waste the useful area of the screen. data such as current value of a process variable. These low alarms mostly correspond to the failure of the sensors. software offset correction is provided for any drift due too temperature or time. 5.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY.6 Resolution of Values in Numeric/Plot/Bar Graph Form Resolution of Values (i. 1 2 Type of output Numeric form Graphic Display/Mimic/Bar Graph/Plot Resolution 0. Hence.2% of full span. 1. alarm point.2% better or Numerical resolution will be limited to 0. Hence numerical displays like 21. A facility for enabling/disabling “low” alarms in bulk for certain points with a single command will be provided.e. Microprocessor based and standalone type I/O subsystems are used. No.causes confusion and inconvenience to the operator while studying the printouts/displays. Initial Display Lag: It is defined as the Maximum Time taken for the first complete display (static + dynamic parts) to appear on the display after the operator’s common will not be more than 2 seconds.CHITTORGARH .UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY. Display Lag: It is defined as the maximum time difference between time stamping of an event and it being displayed will not be more than 1 second. 1.8 Data Storage/Retrieval and Off-line Computer System 1. Sampling interval: It is defined as the maximum time between Print Lag: It is defined as maximum time difference between the two consecutive scanning of the inputs 5.1 Data Storage The following on-line data will be recorded on the magnetic disk for last 32 hours: a) b) c) d) e) History data Static data base Changes done in static data base Five sets of DNM data & ECCS Test Data Alarm logging 49 SUBMITTED BY: .8.1. 3. 4. 2. the commencement of the demanded printout and the operator’s commands and will not be more than 10 seconds.7 Response Time Expected response times are described as follows: 1. Time Stamp Lag: It is defined as the maximum time difference between the real time of a field event occurrence and the time stamp (Time stamp will be done as soon as the scanning is done) will in principle be same as the sampling interval. This data for the last 24 hours. on default.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY.2 Data Retrieval Provision will be made to retrieve the data from the disk (current 24 hours) or from any previously recorded magnetic tape and store it on a PC (MS-DOS) compatible floppy.). 1. etc. It will be possible to read the data recorded on floppies by the on-line system .C. will be dumped on to the magnetic tape one in a day at a fixed time.f) g) Snapshot of current values of all the points at every shift and as Data and time of recording the data. if the tape on the drive is of that day’s tape. one tape will be used for a day and previous one month’s data will be stored (i.8. If not.e.The software would also include standard package like DBASE IV. Facility will be provided to select any type of data and in any range (time. system will check. power supply of the following specifications will be available in the station. which will be adjustable on system starting time. Two independent sources of single phase. Before dumping the data. A. Typically. it will ask the operator to insert new tape for dumping the data. 1. Voltage 50 SUBMITTED BY: .3 Off-line computer system Off-line computer system will comprise of a standard PC-AT and a printer. usi.CHITTORGARH . 1.8. demanded by the operator. 31 tapes will be available).9 Input Power Supply to the Equipment and Effect of Power Failure. power interruption (total outage) lasting 30 milliseconds or less will not affect the working of the COIS in anyway. 1.1 1.c. power supplies will be connected to the load through isolation diodes.C.RMS Value Steady state variation Transient variation Frequency Frequency Steady state variations Transient variation : 240 Volts + 10% : + 10% : 0% (for 200m secs) : 50 Hz : + 1% : + 5% During transient variations (upto 200m sec) the COIS will continue to operate without malfunctioning. Seismic specification The I/O subsystem equipment will operate satisfactorily during and after the vibration tests at the following peak accelerations when subjected to a sinusoidal acceleration for 30 seconds at each frequency in the given range.c.10 Master Clock Time 51 SUBMITTED BY: .C. power supplies are used.9. Peak acceleration I the horizontal axes and vertical axis: 3.5g from 1 Hz to 33 Hz. Wherever duplicated D. separate a. For all 240V AC loads. main source will be given to the two D. 1.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY. both sources of main supply will be connected through contractors such that failure of any main power supply will not affect operation of any subsystem. An input a.CHITTORGARH . a master and hot standby computer redundancy is employed. 1.CHITTORGARH . plotters and CRT’s will be 4000 hours or more with an availability of 99. In order to achieve the high availability figures. The meantime to detect a fault (MTTD) plus the mean time to detect a fault (MTTD) plus the mean time to repair (MTTR) will not exceed 1 hour.Real time clock of the COIS Unit-1 will be used as the master clock for synchronizing time of various computer systems of the plant. 52 SUBMITTED BY: . To keep the MTTD+MTTR under one hour. In case of a computer going faulty. The contact status change will be sensed by each of the computer based systems and the time will be set to 10:00:00 hrs.9% or better.11 Reliability and Availability The meantime between failures (MTBF) of the system excluding the printers.UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY.5 second status change at 10. The COIS will provide a potential free change over contact to each of the computer based systems for time synchronization with 0.00 hours every day (Normal status will be resumed at 10:00:00 hours). MTBF and availability figures for the printers/plotters and CRT’s will be 2000 hours and 99% respectively. its load will be automatically switched over to the other computer. ‘hot repairs’ concept is used. become active automatically without operator’s intervention after switching over pertaining to History will not be lost due to such switchover. Displays/printouts active before the failure of computer. CHITTORGARH .UMESH KUMAR MEHAR RAJASTHAN INSTITUTE OF ENGINEERING & TECHNOLOGY.53 SUBMITTED BY: .