But now, with growing worries about climate change caused by the use of fossil fuels, nuclear energy looks set for a renaissance.
There are more than 400 nuclear reactors in use around the world. The UN's nuclear watchdog, the International Atomic Energy Agency (IAEA), says the electricity generated by nuclear power could quadruple in the next few decades.
This worries environmentalists, but not only them. In the present era, the danger is that rogue regimes will gain access to military nuclear processes and terrorists to radioactive materials, as Dutch nuclear expert Dick Leurdicjk explained.
"The more nuclear energy you will see in the future for peaceful purposes, the bigger indeed -- there is a direct relationship -- the danger is for the misuse of nuclear energy for nonpeaceful purposes. Absolutely," Leurdicjk said.
The problem is that technology used in a civilian nuclear program is -- in its basic stages -- the same as that used for military programs. For instance, Iran's decision to resume the process to enrich uranium has angered Washington because that material can be used for both civilian and military purposes.
While Iran and also North Korea's nuclear intentions grab the proliferation headlines, less noticed events elsewhere reveal the pressures being put on international nonproliferation efforts.
As IAEA spokesman Mark Gwozdecky said, things have changed drastically since the Nuclear Non-Proliferation Treaty (NPT) was signed in 1970: "There were [then] relatively few countries within reach technologically of producing fissile material. Now we can see possibly as many as 40 countries who are capable of producing fissile material, and therefore capable of getting close to having a nuclear weapon."
An example of the difficulties facing UN control efforts is Brazil. Experts from the IAEA arrived there this week to examine that country's new program to enrich uranium.
But Brazilian authorities have declined to allow unrestricted inspections of the facility, saying it fears secrets for a new process of uranium enrichment could be leaked to commercial competitors. Instead, Brazilian officials have so far only offered limited access to centrifuges. The Brazilian plant cannot legally start operating until it is approved by the UN agency, however.
No one seriously believes Brazil is developing nuclear weapons, although Brazil's previous military rulers are said to have once harbored such dreams. But the bargaining over inspections indicates the possibilities for concealment where the will is there.
"My feeling is that, at present, the existing safeguard system will not prevent, ultimately, a nation from developing a nuclear [weapons] program, if it has decided to do that," Leurdicjk said.
South Korea provides another example of the fragility of the international control regime. Seoul recently admitted that its scientists covertly enriched uranium in 2000 and had earlier separated plutonium.
The government said the experiments were done without its knowledge or approval. Only now, after the experiments have stopped, is the IAEA making intrusive inspections of South Korea's facilities.
As a consequence of such incidents, doubts are growing about the effectiveness of the NPT.
"We definitely are in need of the NPT under the present conditions," Leurdicjk said. "But at the same time, I have the feeling that this will not be enough to counter all the potential threats which are still hanging in the air."
Another researcher, Maurizio Martellini of the University of Como in Italy, said economic mechanisms favor proliferation. He said a key feature of globalization -- or international economic integration -- is that it inevitably narrows the gap in technological knowledge between rich and poor countries.
One of the consequences of this will be that knowledge of nuclear and dual-use technologies will be increasingly available throughout the "global village."
In addition, Martellini said, the commercial market tends to take over technologies originally developed for defense purposes.