Like carbon, Uranium exist as multiple isotopes. 99% exists as U238, while less than 1% exists as the radioactive/fissionable U235 isotope. Neutrons stabilize the nucleus of an atom. U235 with 3 fewer neutrons, does not contain enough neutrons to stabilize such an enormous nucleus. Consequently, U235 atoms will spontaneously split, releasing additional neutrons and enormous amounts of energy. The brake-down products of this natural radioactive decay includes smaller atoms such as lead, and radon gas. Radon that many people worry about in the basements of their homes is the by-product of the radioactive decay of naturally occuring U235 found in the Earth's crust.
Because uranium exists mostly of the non-radioactive U238 isotope, it must be processed before it can be used as fuel in a nuclear reactor. But, separating isotopes is not an easy or inexpensive process. To purify and consentrate U235 from U238, the metal is converted into a gas which is spun in an ultracentrifuge. The sliqht difference in mass is enough to separate U235 from U238. The gas is then converted back into a metal (Zirconium) which is then processed into fuel rods for use in a nuclear reactor core. Now the purifying and processing part is the hard part. And because it's so expensive, the process is absolutely clean; not an atom of U235 is wasted. The left-over U238 is not radioactive and is used by the military as tank armor and as depleted uranium in armor piercing munitions.
Making electricity from reactor-grade uranium is easy. Have you ever seen Indiana Jones and the Temple of Doom. It's kinda like when Indiana places the Shinkara Stones next to each other causing them to glow. That's how uranium works. You simply get enough U235 in one place and it heats up. If you reach critical mass, then you get a self-sustaining reaction where neutrons from the fission of one U235 cause the fission of neighboring U235 and so-on causing a nuclear explosion. Inside a reactor core, U235 is separated into fuel rods which are separated by a series of neutron absorbing boron control rods which prevent the U235 fuel rods from overheating and melting (meltdown) or exploding. The fuel rods and control rods are placed in a pressurized water boiler. The control rods are remotely removed from inbetween the fuel rods, the rods heat up and heat up the surrounding water making steam which then is used to drive the turbins of electric generators.
You don't need 100% U235 to run a nuclear reactor. Reactor grade uranium is only 3-4% U235. On the other hand, weapons grade uranium is 90% U235. So, instead of purifying uranium to weapons grade purity, the US has adopted a cheaper and dirtier method of obtaining large amounts of fissionable material for bombs. Plutonium. Making plutonium is easy. You simply put U238 next to U235 and you make Pu239. Separating Pu239 from U238 is easy. Becuase Pu and U are different elements they have different chemical properties and can be separated using solvents. However, that creates 2 problems. First, you created something radioactive out of something that originally wasn't radioactive and Second, you have all this left-over solvent with traces of radioactive Pu239 in it.
I am living in Augusta, Ga which just so happens to be home to one of the nation's most important nuclear labatories, the Savannah River Site. The SRS is the country's center for putonium production and processing. Consequently, after decades of bomb making, SRS is full of thousands of barrels of toxic mixed waste and radioactive sludge left over from separating Pu239 from U238. Already, the barrels of high-level mixed waste are rusting, the concrete liners are cracking and radioactive solvent is seeping into and contaminating local ground water.
Fortunately, SRS scientists have come up with an ingenious way to help this situation. The process is called vitrification or glassification. Currently, the tens of thousands of barrels of solvent are undergoing a process whereby the solvent is safely evaporated away leaving only a radioactive tar or precipitate salt behind which is then encased in glass, which is encased in concrete and then steel. These new containers are being prepared for safe shipment to a permenent repository at Yucca Mountain.
Fuel rods don't last forever. On average, a fuel rod is changed every 3 years . Within a reactor core, 1/3-1/4 of the fuel rods are replaced every 12-18 months. This is because, as the controlled fission occurs, fission products build up and poison the reaction. The fuel rods themselvs can become brittle as the uranium metal degrades into byproduct salts. The fuel rods can fracture if not replaced. This usually leaves a large percentage of unreacted U235 which some countries like France recycle. However, others are against recycling because it creates more mixed waste and radioactive salts that would also require disposal. The US produces plenty of U235 and therefore currently practices a "use once" policy for its fuel rods.
Utah is one of the largest sources of uranium ore in the world. Expensive oil and fears of global warming are triggering a new uranium mining and processing boom in Utah. Fear over nuclear energy hurt the the uranium economy in Utah during the 1980's and 90's. Uranium processing companies which operated in the 1940's and 50's left behind large tailing piles and contaminated soil which later became EPA superfund sites. One of these sites was located in South Salt Lake. Thousands of tons of tailings and contaminated soil were trucked from the old processing factory which was once outside city limits in 1950 but now was in the middle of residental section of Salt Lake City today. All that dirt was moved to a dump site in west Utah dessert.
Not long after, a company bought desert realestate nextdoor to the dump site and asked the state for permission to create a business there to dispose of medical-grade and low-grade radioactive waste. Utah approved the request and Envirocare was born. Other states like Washington, Denver and South Carolina have similar companies but Envirocare had a huge advantage. Other states taxed their businesses because they feared that after the company had made it's money, the state would be left with a nuclear waste dump which could have caused problems centuries into the future. The collected tax funds were placed in an account to cover future clean-up costs. However, Utah does not tax Envirocare because Evirocare smartly started up shop nextdoor to an existing radioactive dump site. They don't get taxed because the area was already a low-level radioactive waste dump. Consequently, Envirocare can undersell all of its competitors.
A couple of years ago Envirocare got ambitious and wanted to expand the kinds of waste it was approved to receive. It didn't want fuel rods or mixed waste; that's for Yucca Mountain. What it wanted was the contaminated equipment, gloves, and boots, and suits the people who work at places like SRS wear and use while processing the high-level mixed waste. Well, had Envirocare won approval, that would have put waste companies in Colorado and Washington out of business. So, Colorado launched one of the most impressive political campaigns since the state's ski resorts combated Utah's drink-by-the-glass initiative. Colorado sponsored a huge misinformation campaign and sent in representatives to gather names on a petition for a ballot proposal which would have put Envirocare out of business. They were successful in getting the signitures and Envirocare was forced to spead millions of dollars on TV, radio, mailers, and newpaper ads fighting the proposition. The ballot proposition failed and Envirocare won its request to receive the new types of low-level radioactive waste.
Envirocare learned an important lesson about the importance of good public relations. Like many companies, they ignored public relations, but when their competition started the negative PR campaign against them, noone in Utah knew who Envirocare was and readily believed the negative propaganda. I was suspicious when I listened to a presentation in favor of the ballot initiative during a lunch-time meeting and every other side in the presentors powerpoint had a mushroom cloud in it.
Since that experience, Envirocare has needed to transform its image. First it changed its name to Energy Solutions. And then the company started sponsoring local events such as the Salt Lake Marathon and other charitable events. But the king of them all is that they paid enough money to rename the Delta Center, home of the Utah Jazz, the Energy Solutions Center. They even started advertizing in Augusta, GA on radio and TV. A neighbor who is a nuclear engineer at SRS told me that the waste contracts were up for bid and Energy Solutions was the clear victor. In fact, Energy Solutions just purchased it's South Carolina competitor NUKEM.