CALIFORNIA, Calif. (KTXL) — On Sept. 2 Gov. Gavin Newsom extended the operation of the Diablo Canyon Nuclear Power Plant with opposition and support from across the state, but what is a nuclear power plant and how do they work?

Diablo Canyon opened in 1985 with its two Westinghouse Pressurized Water Resource reactors.

“The two units produce a total of 18,000 gigawatt-hours of clean energy and reliable electricity annually, which is enough energy to meet the needs of more than three million Northern and Central Californian’s.” Pacific Gas and Electric states on their power plants website.

In July, 92 reactors were operating across the United States at 54 power plants. Thirty-two of the plants have two reactors and three plants have three reactors, according to the United State Nuclear Regulatory Commission (U.S. NRC).

The basic steps of the power plant is to use uranium fission to heat water, which turns into steam and the steam then spins steam turbines that run a generator which produces power.

Uranium heats the water by undergoing fission, the splitting of atoms, which causes a release of energy and heat, according to the US Office of Nuclear Energy. The reactor helps house and control that nuclear fission.

The core of the reactor is made up of fuel rods, which are ceramic pellets of uranium 235 that are stored in tubes, according to the International Atomic Energy Agency (IAEA). The tubes are then bundled together, usually as many as 200, to make a fuel assembly in which a reactor can have 150 to 200 fuel assemblies.

One of those uranium ceramic pellets can hold as much energy as 150 gallons of oil and enriched uranium can be used as fuel for three to five years, according to the U.S. Energy Information Administration.

The core is submerged in water which fulfills two roles: as a coolant for the core and also to moderate the speed of the neutrons to make sure there is a sustained fission chain reaction, according to the office of Nuclear Energy.

The unused steam is sent to a cooling tower where it is cooled and then condensed back to a liquid state to be run through the reactor again, according to the U.S. NRC.

According to PG&E, Diablo Canyon avoids emitting 6 to 7 million tons of greenhouse gas per year compared to a “conventional generation resource”.

After the fuel rods are spent they become radioactive waste which is classified as ‘high-level waste’, according to the IAEA, and are placed several meters underground. Before then it is stored in purpose-built storage areas.