Thorium-Based Nuclear Reactors
Department of Atomic Energy (DAE) has planned the use of large deposits of Thorium available in the country as a long-term option.
- A three-stage nuclear power programme has been chalked out to use Thorium as a viable and sustainable option, right at the inception of India’s nuclear power programme.
- The three stage nuclear power programme aims to multiply the domestically available fissile resource through the use of natural Uranium in Pressurised Heavy Water Reactors, followed by use of Plutonium obtained from the spent fuel of Pressurised Heavy Water Reactors in Fast Breeder Reactors.
- Large scale use of Thorium will subsequently follow making use of the Uranium-233 that will be bred in Reactors. The utilisation of Thorium, as a practically inexhaustible energy source, has been contemplated during the third stage of the Indian Nuclear Programme.
- As is the case with generation of electricity from Uranium, there will be no emission of greenhouse gases from Thorium also and therefore, it will be a clean source of energy.
- It is not possible to build a nuclear reactor using Thorium (Thorium-232) alone due to its physics characteristics. Thorium has to be converted to Uranium-233 in a reactor before it can be used as fuel.
- Development of technologies pertaining to utilisation of thorium has been a part of ongoing activities in Department of Atomic Energy. With sustained efforts over the years, India has gained experience in different areas of Thorium fuel cycle. Efforts are currently on to enlarge the present Thorium related R&D work and activities to a bigger scale and towards development of technologies for the third stage of our nuclear power programme. Safety has been accorded paramount importance in all Thorium technology development studies.
- Commercial utilisation of Thorium, on a significant scale can begin only when abundant supplies of either Uranium-233 or Plutonium resources are available. Accordingly, the large scale introduction and utilization of Thorium in the programme has been contemplated after an adequate inventory of Plutonium becomes available from our Fast Breeder Reactors (FBRs), comprising the second stage of Indian nuclear power programme.
- This will be after a few decades of large scale deployment of FBRs. In preparation for the utilisation of Thorium in Third Stage of India’s Nuclear Power Programme, efforts towards technology development and demonstration are made now so that a mature technology for Thorium utilisation is available in time.
Power Generation through Nuclear Energy
Atomic Energy Commission (AEC) set up in 1958, is the apex body regarding use of nuclear energy, it formulates policy of the Department of Atomic Energy in all matters concerning nuclear energy.
- The targets for nuclear power generation are set on an annual basis, as a part of Nuclear Power Corporation of India Limited (NPCIL)’s annual Memorandum of Understanding (MoU) with Department of Atomic Energy (DAE) considering planned biennial shutdowns (BSD) of units during the year, connections of new units to the grid if any, during the year etc. The generation target for the year 2018-19 was 36904 Million Units (MUs).The actual generation in the year 2018-19 was 37813 MUs.
- The Government has planned to increase the installed capacity base of nuclear power in the country for increased electricity production from nuclear power.
- The present installed nuclear power capacity of 6780 MW would reach 13480 MW by the year 2024-25 with the completion of projects under construction (including 500 MW Prototype Fast Breeder Reactor (PFBR), being implemented by Bharatiya Nabhikiya Vidyut Nigam Ltd. (BHAVINI).
- The Government has also accorded administrative approval and financial sanction for 12 nuclear power reactors aggregating a total capacity of 9000 MW, which are scheduled to be completed progressively by the year 2031. On their completion, the total nuclear power capacity would reach 22480 MW. More reactors based on both indigenous technologies and with foreign cooperation may be planned in the future.
Steps Taken by Indian Railways to Reduce Train Accidents
Indian Railways have taken several key measures, as a result of which the number of consequential train accidents have decreased from 118 in 2013-14 to 104 in 2016-17, to 73 in 2017-18 and further to 59 in 2018-19. These are the lowest ever figures in the history of Indian Railways.
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- Safety is accorded the highest priority by Indian Railways and all possible steps are undertaken on a continual basis to prevent accidents and to enhance safety of passengers.
Following steps/measures have been taken to prevent accidents:-
- Rashtriya Rail Sanraksha Kosh (RRSK) has been introduced in 2017-18 for replacement/renewal/upgradation of critical satety assets, with a corpus of ₹1 lakh crore for five years, having annual outlay of ₹ 20000 crore.
- Indian Railways has already adopted the technological upgradation in safety aspects of coaches and wagons by way of introducing Modified Centre Buffer Couplers, Bogie Mounted Air Brake System (BMBS), improved suspension design and provision of Automatic fire & smoke detection system in coaches. These modifications are being provided in newly manufactured coaches and wagons on a regular basis.
- Conventional ICF design coaches being replaced with LHB design coaches of Mail/Express trains in phased manner.
- A GPS based Fog Pass device is being provided to loco pilots in fog affected areas which enables loco pilots to know the exactdistance of the approaching landmarks like signals, level crossing gates etc.
- In order to improve safety, modern track structure consisting of Prestressed Concrete Sleeper (PSC), 60 KG, 90 or higher Ultimate Tensile Strength (UTS) rails, fanshaped layout turnout on PSC sleepers, Steel Channel Sleepers on girder bridges is used while carrying out primary track renewals.
- Long rail panels of 260 M/130M length are being manufactured at the steel plant to minimize number of Alumino Thermit joints in the track.
- Provision of Thick Web Switches (TWS) is planned for all important routes of IR. To expedite provision of TWS, procurement of Thick Web Switches has been decentralized to zonal railways.
- Ultrasonic Flaw Detection (USFD) testing of rails to detect flaws and timely removal of defective rails.
- Mechanization of track maintenance is being carried out to reduce human errors and track management system has been introduced on Indian Railways for development of database and decision support system and to decide rationalize maintenance requirement and optimize inputs.
- Electrical/Electronic Interlocking System with centralized operation of points and signals are being provided to eliminate accident due to human failure and to replace old mechanical systems. Track Circuiting of stations to enhance safety for verification of track occupancy by electrical means instead of human element. Axle Counter for Automatic clearance of Block Section (BPAC) to ensure complete arrival of train without manual intervention before granting line clear to the next train and to reduce human element.
- Train Protection and Warning System: Train Protection and Warning System (TPWS) based on European Technology ETCS Level-1, a proven Automatic Train Protection (ATP) System to avoid train accident /collision on account of human error of Signal Passing at Danger (SPAD) or over speeding, has been provided on (i) Noapara – Kavi Subhash section of Kolkata Metro (28 RKMs) (ii) Chennai – Gumidipundi suburban section of Southern Railway (50 RKMs), Basin Bridge – Arrakkonam section of Southern Railway (67 RKMs) (iii) Hazrat Nizamuddin – Agra section of Northern/North Central Railway (200 RKMs).
- Auxiliary Warning System (AWS): An ATP called Auxiliary Warning System (AWS) is presently functional on 413 RKMs in the Mumbai suburban section of Central Railway (289 RKMs) and Western Railway (124 RKMs).
- Train Collision Avoidance System (TCAS): TCAS is an Automatic Train Protection (ATP) System being developed in association with 3 Indian manufacturers. The system has been installed on Lingampalli – Vikarabad – Wadi, Vikarabad – Bidar section (250 RKMs) on South Central Railway. Extensive field trials and safety validation of the system to Safety Integrity Level 4 (SIL-4) by Independent Safety Assessors (ISA) has been completed. Product of all the 3 firms has been approved by RDSO for developmental order for speeds up to 110 Kmph in Absolute Block Sections.
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