Nuclear Reactors and Energy Quiz

Turbines and Steam Condensers

• Velocity compounding method is used in Ratean and Zoelly turbines.
• Optimum blade speed ratio for maximum blade efficiency or maximum work done is given by = cos 2.
• Velocity-compounded impulse turbine has high steam consumption and low efficiency.
• The degree of reaction of reaction turbine stage is defined as the ratio of heat drop over fixed blades to the total heat drop in the stage.
• The efficiency of steam turbine is considerably reduced if throttle governing is carried out at low loads.
• Nozzle control can only be applied to reaction turbines.
• A steam condenser is a device or an appliance in which steam condenses and heat released by steam is absorbed by water.
• In jet condensers, the exhaust steam and water do not come in direct contact with each other.
• In counter-flow type jet condenser, the steam and cooling water enter the condenser from opposite directions.
• Low level counter flow jet condenser is also called barometric condenser.
• In an injector condenser, the exhaust steam and cooling water mix in hollow truncated cones.
• A jet condenser entails high manufacturing cost.

Hydrology and Hydrograph

• Hydrology is a science that deals with the depletion and replenishment of water resources.
• Precipitation includes all the water that falls from the atmosphere to earth's surface.
• Run-off can also be named as discharge or stream flow.
• Hydrograph indicates the power available from the stream at different times of day, week, or year.
• Flow duration curve is plotted between flows available during a period versus the fraction of time.
• The 'firm power' is also known as the primary 'power'.
• A mass curve is the graph of the cumulative values of water quantity (run-off) against time.

Steam Power Plants and Thermodynamics

• Thermal efficiency of steam plants is of the order of 30%.
• Blowing down of boiler water is the process to control the solid concentration in the boiler water by removing some of the concentrated saline water.
• In regenerative air pre-heater, heat is transferred from heating an intermediate material and then heating the air from this material.
• The height of the chimney in a steam power plant is governed by the control of pollution.
• Deaerative heating is done to remove dissolved gases in the water.
• Reheat factor is the ratio of cumulative actual enthalpy drop for the stages to total isentropic enthalpy heat drop.
• The value of the reheat factor is of the order of 0.8 to 1.0.
• Compounding of steam turbine is done for reducing the rotor speed.
• Topping turbines are turbines.

Gas Turbines

• In a two-stage gas turbine plant, reheating after the first stage increases thermal efficiency.
• In a two-stage gas turbine plant, with inter-cooling and reheating, both work ratio and thermal efficiency improve.
• For a jet propulsion unit, ideally the compressor work and turbine work are equal.
• Greater the difference between jet velocity and airplane velocity, greater the propulsive efficiency.
• For starting gas turbines, the turbine rotor is usually motored up to 'coming in' speed which is equal to half of the rated speed of the gas turbine.
• The blades of the gas turbine rotor are made of high nickel alloy (Nimic 80).
• Maximum temperature in a gas turbine is of the order of 1600°C.

Nuclear Power Plants

• A CANDU reactor uses natural uranium as fuel and heavy water as moderator and coolant.
• Fission of U235 releases 200 MeV energy.
• Fast breed reactors are best suited for India because of large thorium deposits.

Power System and Economics

• A load curve indicates average power used during the period.
• Annual depreciation as per straight line method, is calculated by the capital cost minus the salvage value, divided by the number of years of life.
• A consumer has to pay lesser fixed charges in two-part tariff.
• In India, the tariff for charging the consumers for the consumption of electricity is based on two-part tariff.
• In Hopkinson demand rate or two-part tariff, the demand rate or fixed charges are affected by the variation in load factor.