The Role of the Heat Exchanger (8.4.6)

A heat exchanger is a device built for efficient heat transfer from one medium to another, whether the media are separated by a solid wall so that they never mix, or the media are in direct contact.

Steam generators are heat exchangers used to convert water into steam from heat produced in a nuclear reactor core. They are used in pressurized water reactors between the primary and secondary coolant loops. The moderator/coolant water is radioactive, so it can not leave the inner reactor containment. Its heat must be transferred to non-radioactive water, which can then be sent out of the reactor shielding.

This is done through the heat exchanger, which works by moving the radioactive water through a series of pipes that are wrapped around other pipes. The metallic pipes conduct the heat from the moderator to the normal water. Then, the normal water (now in steam form and intensely hot) moves to the turbine, where electricity is produced.

heat_exchanger.jpg




Sources

· "Heat exchanger." Wikipedia, the free encyclopedia. 31 Mar. 2009 <http://en.wikipedia.org/wiki/Heat_exchanger>.

· "Steam generator (nuclear power) -." Wikipedia, the free encyclopedia. 31 Mar. 2009 <http://en.wikipedia.org/wiki/Steam_generator_(nuclear_power)>.

· "The Nuclear Fission Power Plant." Thinkquest. 30 Mar. 2009 <http://library.thinkquest.org>.