State Factors Affecting The Site Selection Of Nuclear Power Plants 4a5272

State factors affecting the site selection of nuclear power plants Ans:Site selection and evaluation are a crucial part of establishing a nuclear power programme and can be significantly affected bycosts andpublic acceptance. While site selection of a nuclear power plant, the aim is to protect the plant against external threats as well as to minimize anyen vironme ntal detriments and threats that might arise from it. Some important factors while site selection: 1.Use of land and water area: Construction is not allowed on shore zones belonging to the coastal area of a sea or of a water system which would otherwise affect ecology. 2.Availability of nuclear fuel, cooling water: The site should be such that the fuel required for nuclear power generation such as uranium and others should be available near the site or transporting such fuel should not be difficult and time consuming. Also PWR, BWR mostly use light water H2O as their coolant as well as so water facility should be available near to the site and in plenty. 3.Population and sources of livelihood in the region: A nuclear power plant site extends to about a kilometers’ distance from the facility. It is defined as an area where only power plant related activities are allowed as a rule. Permanent settlement is prohibited and only very limited employee accommodation or recreational settlement is allowed. 4.Human activities and human facilities: In the plant’s vicinity there may not be facilities or population centres where the necessary protective measures, such as sheltering indoors or evacuation, would be difficult to implement. In the plant’s vicinity, no activities may be carried out that could pose an external threat to the plant. The general principle in the siting of nuclear power plants is to have the facilities in a sparsely populated area and far away from large population centres. What justifies placement in a sparsely populated area is that emergency planning will then be directed at a smaller population group and will thus be easier to implement. The licensee responsible for the operation of the nuclear power plant shall have authority of decision over all activities in the area and shall be able to remove unauthorised individuals from the site, if necessary, or prevent such individuals from entering it. The plant site may contain other non- facility related activities provided that they do not pose a threat to plant safety 5.External threats and environmental threats: Examples of exceptional natural phenomena include • Freezing or other clogging of the cooling water intake •

Storms •

Flood 6.Seismic area evaluation: Earthquake is a biggest threat to nuclear power plant and hazardous accidents might take place if the earthquake strikes the site. 7.Transport arrangements and Traffic arrangements: Transport system to the plant should be smooth and should not affect the working of plant due to delays in transporting necessary material, men etc to the plant. A traffic lane may traverse the site if the volume of traffic is small and if

traffic can be directed elsewhere, if necessary. Visits onsite are allowed provided that the licensee has the possibility to control the movement of visitors. 8.Radioactive releases: Radiation is harmful to human life as well as ecology. It causes harmful effects and diseases to human life. According to the radiation exposure, limit on population around the plant is selected. When radiation doses to the surrounding population are calculated, the region’s special characteristics— hydrological, geological and meteorological— as well as the living conditions and habits of the population shall be considered.

9.Protective zone: The plant site is surrounded by a protective zone extending to about a five kilometer distance from the facility. Land use restrictions are in force within the zone. Dense settlement and hospitals or facilities inhabited or visited by a considerable number of people are not allowed within the zone. The zone may not contain such significant productive activities as could be affected by an accident at the nuclear power plant. The number of permanent inhabitants should not be in excess of 200. The number of persons taking part in recreational activities may be higher, provided that an appropriate rescue plan can be drawn up for the area. 10.Supply of electric power: Reliable electric power transfer to the national grid and specific factors relating to the security of supply of electric power.

Draw a neat sketch of nuclear reactor and State various components of nuclear reactor. Ans: A nuclear reactor is a device in which nuclear chain reactions are initiated, controlled, and sustained so that heat will be produced continuously which can be further utilized for power generation. •

A nuclear power plant uses the heat generated by a nuclear fission process to

drive a steam turbine which generates usable electricity. •

Fission is the splitting of atoms into smaller parts. Some atoms, themselves tiny,

split when they are struck by even smaller particles, called neutrons. Each time this happens more neutrons come out of the split atom and strike other atoms. This process ofenergy release is called a chain reaction. •

Control rods, s, shielding, piping arrangements make nuclear reactor

as a whole

Q3 – Explain with neat sketch working of Pressurized water reactor. Ans: The pressurized water reactor is a light water type reactor i.e. the and coolant are both light water (H2O). Fuel used in PWR is enriched uranium U235 in form of thin plates.