What are the two types of nuclear power?

Answer 1

The two designs built commercially in the US are the Pressurised Water Reactor (PWR) and the Boiling Water Reactor (BWR). Both these use ordinary water as moderator and coolant.

In Canada the Heavy Water Moderated design (Candu) has been built in numbers.

In France a large number of PWR's has been built.

In the UK, the gas cooled design was the main build for many years. These use a graphite moderator and CO2 coolant. The first series used natural uranium with a magnesium alloy fuel cladding, but the temperature level permitted with this type of fuel was fairly low. The Advanced Gas Cooled reactor used enriched UO2 fuel with stainless steel cladding which allowed higher gas temperature. These were fairly successful, but expensive to build. Any future reactors in the UK will be PWR or BWR.

It is possible to build a reactor which uses fuel in the form of large pebbles, with helium coolant, driving a gas turbine directly, without a steam circuit. Time may tell whether this is really a practical commercial design.

Another possible design is a reactor that uses fast neutrons. A power producing prototype was built in Scotland at Dounreay, but ultimately it was found that material problems made it too difficult to bring into commercial use.

Answer 2

In the electric utility industry, there are three main types of power plants, categorized according to the functions they perform. These are called "base," "intermediate" and "peaking" facilities.

Answer 3

The basic structures of a nuclear plant include... The reactor pressure vessel. This contains the nuclear fuel and the reactivity control system (rods). In a boiling water reactor, water pressure is such that water boils to steam near the top, and that steam directly drives the turbine. The recirculating system. This allows water to recirculate through the reactor. This aids in cooling and also aids in power control at higher power levels. In a pressurized water reactor, pressure is higher and reactor water does not boil, instead it goes to the primary heat exchangers where it boils secondary water which drives the turbine. The turbine. The steam generates rotational energy which spins the exciter and generator. The electrical (power) systems. This manages the output of the generator and steps it up to the required voltage for transmission. The condenser. Steam leaving the turbine is condensed back to water. The circulating water system. Heatsink water is taken from the river or sea and used in the condenser to cool the steam back to water. The reheaters. Extraction steam is taken from various points in the steam lines and used to heat the water back to a temperature that will not shock the reactor, or increase reactivity due to cold water moderation. The emergency power systems. These provide electrical power in the case of loss of offsite power, so as to bring the reactor to a safe shutdown condition when the plant is isolated. The balance of plant systems. These are the various other systems that are not nuclear steam related, such as plant heating and cooling, etc. The control systems. This includes the control room and related electrical systems. The isolation systems. This allows the reactor to trip and be isolated so that radioactivity release can be controlled. The suppression system. This includes the suppression pool (typically in a boiling water reactor) which can take the initial load of steam in an isolation. The emergency systems. This includes high and low pressure water supply systems, emergency moderator systems (boron), ultimate cooling connections, etc. The radiation monitoring system. This measures process and area radioactivity, as well as effluent release radioactivity, both in normal conditions and in emergency conditions. The fuel handling systems. This allows the reactor to be refueled during periodic refueling outages. Some designs, such as the Canadian Heavy Water (Deuterium) reactors, can be refueled while online. US designs require an outage.

Answer 4

...mode 1...power > 5%

...mode 2...startup < 5%

...mode 3...hot standby > 350 degrees

...mode 4...hot shutdown < 350 degrees

...mode 5...cold shutdown < 200 degrees

...mode 6...refueling <140 degrees

Answer 5

Nuclear fission and nuclear fusion

Answer 6

wind power