As more countries look to nuclear power as an energy source, stricter controls over technologies for enriching uranium will be necessary because primary usage as a source of energy could eventually be abused for weapons-making, and potentially hazardous nuclear substances could spread more widely. There are also fears that terrorists will find easier access to bombs or other dangerous materials as more lines are crossed in the bomb-making business. That is why Iran’s nuclear program has become a major focus of global politics today; namely, the suspicion that this program would ultimately be used for nuclear weapons development, despite the official position of the Iranian government that its nuclear activities are entirely for peaceful purposes, and that it has no intentions of proliferation.
Production of highly enriched uranium (fissile material) is the most difficult step in making a nuclear weapon. Fissile materials can be produced by either making plutonium-239 (an isotope of plutonium) in a nuclear reactor or enriching uranium to increase its uranium-235 (an isotope of uranium) content. The latter has historically been the more obscure option. However, with recent advances in gas centrifuge technology, uranium enrichment has become a particularly attractive option for acquiring a first nuclear weapon. The gas centrifuge is the most economical and efficient way to enrich uranium for peaceful power-reactor fuel (Wood, Glaser, Kemp). As a result, it is essentially impossible to abandon this technology, and very difficult to control it politically. The challenges related to centrifuge proliferation have been underscored by the controversy surrounding Iran’s nuclear program.
Iran’s nuclear program was first revealed by non-government sources in August 2002. In February 2003, Iran confirmed that it was building two centrifuge plants, including one at Natanz (a city in central Iran). Inspection of the Natanz site by the International Atomic Energy Agency (IAEA) revealed that Iran had not declared past uranium enrichment experiments. The IAEA also found traces of highly-enriched uranium, which suggested a foreign origin for some of the equipment (IAEA). Iran acknowledged that it had indeed conducted a limited number of enrichment tests in the years 1999 and 2002. Subsequently, Iran suspended its enrichment program in November 2003, and also voluntarily signed an additional protocol giving the IAEA broader access to Iran’s nuclear facilities. This is confirmed by the November 2007 US National Intelligence Estimate, which stated “with high confidence that in fall 2003, Tehran halted its nuclear weapons program” in response to international pressure (The National Intelligence Council).
Iran resumed centrifuge production in June 2004, and enrichment activities in January 2006, after diplomatic efforts to persuade it to abandon its nuclear program collapsed. In an attempt to deprive Iran of hope for rapprochement, President Bush categorized Iran with terrorist groups. His words created a more unified Iran, more supportive of the Islamic Republic. In return, Khamenei (Iran’s political leader) used harsh words to describe America, to further demonstrate the theocracy’s intent to resist American pressure. President Bush implied that if Iran’s government proved unwilling to act according to the United States’ wishes, America would consider a military attack on Iran. Anxiety over nuclear weapon proliferation was a key factor when it came to the outcome of the 2005 presidential election in Iran, as increased tension between Iran and the United States created a more nationalistic Iran (Zangeneh). International pressure on Iran to halt its nuclear activities resulted in the election of a president (Ahmadinejad) who used the centrifuge program, as well as tough rhetoric against the United States, as a platform for winning domestic political support.
Following the 2005 presidential election, Iran began testing the first complete 164-machine centrifuge cascade, and reported successful production of minute quantities of low-enriched uranium in April 2006 (IAEA). The IAEA referred Iran’s case to the United Nations Security Council, which passed Resolution 1696 in July 2006. The UN Resolution demanded that Iran suspend all enrichment-related activities, including research and development. Iran defied the UN Resolution, and continued its enrichment project, which enjoyed broad domestic support. In its February 2009 report, the IAEA estimated that as of the end of January 2009, Iran had about 1,010 kg of 3.5%-enriched uranium hexafluoride (UF6), which contained about 683 kg of 3.5%-enriched uranium metal (IAEA). Processing that amount of UF6 in an ideal, loss-free centrifuge cascade could produce a maximum of 25 kilograms of 90%-enriched uranium metal. This would be equivalent to the amount the IAEA believes is sufficient to make one first-generation nuclear weapon.
To put things in perspective, it is helpful to examine how much highly-enriched uranium is required for building a nuclear weapon. A gun-type bomb, like the one used over Hiroshima, can be easily made, but would require about 50 kilograms of 90%-enriched uranium- twice the maximum amount that Iran could possibly produce in a loss-free cascade (Cirincione, Wolfsthal, Rajkumar). An implosion-type bomb, like the one used over Nagasaki, would require only 18 kilograms of highly-enriched uranium (Cirincione, Wolfsthal, Rajkumar). However, an implosion-type bomb is much more sophisticated than a gun-type bomb, and requires specialized components that are very difficult to obtain. Iran has reportedly investigated implosion-type designs in the past, but, according to the IAEA, terminated its development effort in 2003 (IAEA).
It appears that even with an ideal, loss-free centrifuge cascade would not allow Iran to produce enough enriched uranium for a gun-type bomb, using its existing UF6 stockpile. More importantly, Iran does not have an ideal, loss-free centrifuge cascade. The centrifuge cascades in Iran’s uranium enrichment facility in Natanz are designed to produce enrichment in the 3-5% range. Process losses in the range of 15-20% should be expected in the Natanz facility (Kemp, Glaser). Based on those figures, the maximum amount of enriched uranium Iran could produce would barely be enough for an implosion-type bomb, assuming that Iran can somehow obtain the additional sophisticated components needed for building an implosion-type bomb.
According to the IAEA, Iran does not have any weapon-grade uranium. All of the documents suggesting weapons-related activities date to before the year 2004, consistent with the November 2007 US National Intelligence Estimate, which judged “with high confidence that in fall 2003, Tehran halted its nuclear weapons program” in response to international pressure (The National Intelligence Council). Using its existing enrichment facility at Natanz, Iran does not have enough low-enriched uranium feedstock to make even one first-generation nuclear weapon. To make a nuclear bomb using only its existing low-enriched uranium stockpile, Iran would have to make significant modifications to its centrifuge cascades. That would require several months to shut down and re-pipe the cascades, followed by 6-9 months of uninterrupted operation, both of which would require Iran to break out of safeguards in a detectable manner. In that case, the international community would have plenty of time to respond. Thus, it appears that media reports during the past ten years suggesting that Iran has enough highly enriched uranium to make a nuclear weapon have been misleading with respect to Iran’s existing capabilities, and have greatly overestimated the amount of weapon-grade uranium that could be produced from Iran’s low-enriched uranium stock.
Works Cited
Cirincione, J., J. Wolfsthal, and M. Rajkumar, “Deadly Arsenals: Nuclear, Biological and Chemical Threats”, Carnegie Endowment for International Peace, Washington, DC (2005). : Web. 2 Oct. 2011.
IAEA, “Implementation of the NPT Safeguards Agreement and Relevant Provisions of Security Council Resolutions 1737 (2006), 1747 (2007), 1803 (2008) and 1835 (2008) in the Islamic Republic of Iran,” International Atomic Energy Agency Report (February 19, 2009) : Web. 2 Oct. 2011.
Kemp, R. Scott and Alexander Glaser, “Statement on Iran’s Ability to Make a Nuclear Weapon and the Significance of the 19 February 2009 IAEA Report on Iran’s Uranium Enrichment Program,” (March 2, 2009) : Web. 2 Oct. 2011.
Shanker, Thom, “U.S. Says Iran Has Material for an Atomic Bomb,” The New York Times (March 1, 2009). : Web. 2 Oct. 2011.
The National Intelligence Council, “Iran: Nuclear Intentions and Capabilities,” National Intelligence Estimate, (November 2007). : Web. 2 Oct. 2011.
Wood, Houston, Alexander Glaser, and Scott Kemp, “The Gas Centrifuge and Nuclear Weapons Proliferation,” Physics Today Volume 61 (2008) : 40-45. Web. 2 Oct. 2011.
Zangeneh, Parisa, “Nuclear Politics, Mahmoud Ahmadinejad, and the Iranian People,” Iran Analysis Quarterly Volume 3 Number 1 (2006) : 11-26. Web. 2 Oct. 2011.
