Iran has completed construction of its Bushehr nuclear power plant located south of the Persian Gulf city of Bushehr. The plant is estimated to undergo testing soon before it becomes fully operational later in 2009. Bushehr nuclear plant was completed with the assistance from Russia and took 35 years to construct.
Siemens AG has been contracted to construct two reactors each producing around 1,200 megawatts, when the project started in 1974 during the reign of the Shah.
The 1979 Iranian revolution has stopped the project. Ayatollah Khomeini has declared nuclear power as anti-Islamic.
Bushehr plant was idle until 1995, when Russia signed an $800 million contract to finish the work on the facility. The single Russian VVER-1000 reactor installed at Bushehr produces roughly 1,000 megawatts of power.
The VVER-1000 is the latest Russian design, which is equal to western designs for pressurized water reactors. They all have the same safety systems, VVER and the western side [designs], and they all have very good containment systems, said Upendra Rohatgi, senior nuclear scientist at Brookhaven National Laboratory.
The VVER-1000 reactor utilizes water for various key functions. Muhammad Sahimi, engineering professor at University of Southern California, said, This reactor uses water both as a coolant and as a moderator. Coolant is necessary to control the temperature of the reactor. The Moderator function is necessary to slow down neutrons from the nuclear fuel, so that neutrons can sustain the nuclear reaction within the reactor.
At Bushehr plant’s light water reactors, nuclear fuel heats first pressurized water circuit. The heat from the primary circuit then heats a second water circuit, which generate steam that drives the turbines which generate electricity.
The reactor at Bushehr plant is a different design than the much older RBMK-type. The Iranian reactor is completely encased in a massive concrete and steel containment vessel.
The reactor is designed to keep radiation from contaminating the environment should an accident take place. There are multiple layers to the vessel to provide that protection, and also has strength to stop an impact or explosion from either inside or outside the structure.
The US government has conducted tests to see if containment vessels could withstand an aircraft impact. Upendra said the results were positive. They found they [containment vessels] can withstand the impact of a fully fueled 767 [jetliner] or F-4 [fighter aircraft]. The testing has been done at [the U.S. government’s] Sandia National Laboratory, and they found the penetration [from impact] is only, like, six centimeters in a one meter-thick concrete wall, Upendra said.
The other key design criteria for nuclear reactors especially in countries like Iran, is resistance to earthquakes.
Sahimi said, The first thing the Atomic Energy Organization of Iran did was extensive studies in terms of the safety of a nuclear reactor from the perspective of earthquakes. Usually, a nuclear reactor is built in an area where the possibility of a major earthquake is very small. As far as I know, there is no major active fault in southern Iran where the Bushehr reactor has been built.”