As evidenced in recent technical reports published in popular industry journals, Iranian researchers continue to experiment with and improve their laser systems. [1] Of particular importance is the interest Iran has displayed in developing laser isotope separation (LIS) techniques, as one method for producing enriched uranium for nuclear fuel -- or for the core of nuclear weapons. Although Iran claims to have ended its work on LIS, suspicions remain that it may be continuing to pursue the technology in secret. The location of this work is alleged to be Parchin, a military facility where Iran has refused to permit the International Atomic Energy Agency inspectors to visit a number of buildings. [2]

Uranium enrichment is the process by which atoms of the desired isotope, uranium-235, which occur at a rate of 0.7 percent in natural uranium, are culled from other unwanted uranium atoms, in particular, uranium-238, and concentrated to make a product that is suitable for use as nuclear power plant fuel (3-5 percent uranium-235) or for nuclear weapons (usually more than 80 percent uranium-235.) In laser isotope separation, lasers are used to selectively excite uranium-235 atoms so that they can be preferentially culled. [3]

In 1974, Iran formed the Laser Physics Group (later named the Laser Research Center or LRC) at the Tehran Nuclear Research Center (TNRC) to begin limited laser research activities. [4] From that time through 2003, several other research components and a pilot LIS facility were constructed in Iran to investigate the two variants of LIS, Atomic Vapor Laser Isotope Separation (AVLIS) and Molecular Laser Isotope Separation (MLIS) techniques. Publicly available information suggests that Iranian scientists received outside assistance from experts in China, France, Russia (and the Soviet Union), South Africa, and the United States. [5] Iran has acknowledged having four contracts with foreign suppliers to support this work. [6]

When in full operation, the LRC had production lines for red helium-neon lasers, CO2 lasers and copper vapor lasers, a glass-tube manufacturing unit, an optical manufacturing unit, a nitrogen laser laboratory, a solid state laser laboratory, a precision laser laboratory, semi-guided laser laboratories, and a polymer laser laboratory. [7] According to the Atomic Energy Agency of Iran (AEOI) website, Iran’s main laser facility is the Research Center for Laser Applications (RCLA). However, most publications seem to be linked to the LRC. Actually the RCLA and LRC may one in the same.

Between 1993 and 2000, the Iranians built a pilot plant for LIS at Lashar Ab’ad and undertook LIS experiments at the RCLA, using imported uranium metal, without declaring the material or the facility to the IAEA. [8] (The material is suspected to have been obtained from the Soviet Union, in 1993.) [9] According to the IAEA, the Iranians dismantled the pilot plant in August 2003 and showed the dismantled equipment to Agency inspectors in November 2003. The Agency also reported that the highest average enrichment achieved by Iranian scientists was 8 percent, and the peak enrichment was 13 percent; only milligram quantities of enriched uranium were collected.

The undeclared use of uranium in a facility with the potential to enrich the material violated Iran’s inspection agreement with the international agency, which requires Iran to declare all nuclear materials within its borders and place them under IAEA monitoring to ensure they are not diverted for nuclear arms. Such comprehensive IAEA “safeguards” are required by the Nonproliferation Treaty (NPT), to which Iran is a party. In the context of the discovery of significant undeclared nuclear activities in Iran, which have sparked widespread concern that the country is pursuing the development of nuclear weapons, the secrecy surrounding the LIS activities and the importation of uranium will be viewed by many observers with suspicion.

Iranian studies of LIS techniques did not end in 2003, however. In a 2004 paper published in Progress in Nuclear Energy, scientists from Amir Kabir University of Technology and Azzahra University investigated both molecular and atomic laser isotope separation methods to “evaluate the potential of each one for more economical fuel fabrication of enriched uranium cells which can be practically used in light water reactors (LWR).” [10]

Other publications from 2004 and 2005 indicate that researchers at the AEOI and in various academic institutes continue to work in the laser field, conducting, inter alia, experiments in ion excitation and extraction using ND:YAG lasers (lasers based on a neodymium-doped yttrium aluminum garnet stone), and tunable dye, CO2 and copper vapor lasers. [11] These experiments, albeit not necessarily directly related to LIS processes or, in some cases, to the nuclear industry, may represent continuous improvements in Iran’s understanding of ion extraction, which would be helpful to perfecting LIS techniques and, eventually, producing highly enriched uranium for nuclear arms.

As was the case with Iraq during the 1980s, Iran has been investing in several types of enrichment technologies in the hopes of improving its overall chances for success in producing enriched uranium to support the country’s presumed nuclear weapons program. LIS, though technologically more challenging than the use of gas centrifuges, offers an important potential advantage for a proliferant state, in that it is far more difficult for outsiders to observe. Laser facilities can be relatively small in comparison to centrifuge plants, given that LIS is a far more efficient enrichment method, with a higher “separation factor,” meaning that far fewer laser units are needed to bring uranium to the high enrichment levels needed for nuclear arms. [12]

To date, however, the open source literature has not recorded the successful use of an LIS system to produce HEU for nuclear weapons. This may be due to the complexity and technological sophistication of LIS systems and to the availability of other less technologically challenging enrichment options. Given this history, and what has been learned about Iran’s past accomplishments with LIS, it appears likely that if Iran’s LIS program is continuing on a clandestine basis, it is most likely still at the research stage.

SOURCES:
[1] See several studies published by Iranian scientists as recorded in the ISI Web of Knowledge database. Some titles include, “Experimental Study of High-Power CW diode-side-pumped ND:YAG Rod Laser,” “Study of Thermal Lensing in a Side Diode Pumped NdLYAG Laser by Using Boundary Element Method,” and “Trend of Laser Research Developments on Global Level.”
[2] According to the National Council of Resistance of Iran (NCRI), laser enrichment is underway in a secret tunnel at the Parchin military site. See, Michael Adler, “Iranian Resistance Claims UN Missed Sites in Iran,” AFP, November 23, 2005; see also, Maurin Picard, “IAEA Inspector in the Hot Seat,” Le Figaro, January 17, 2006. Picard wrote, “At Parchin…it was established that Iran had acquired by devious routes the procedures for casting and machining the uranium metal necessary for the design of a nuclear warhead, as well as laser-based enrichment technology, which has nothing to do with a civilian process.”
[3] Charles D. Ferguson and Jack Boureston, “IAEA Puts Iranian Laser-Enrichment Technology in the Spotlight,” Jane’s Intelligence Review, July 2004, p. 41.
[4] “Paper Details Work of Laser Research Center,” Ettela’at, in FBIS, ID FBIS-NES-93-076
[5] See “Nuclear Imports” table, Nuclear Threats Initiative, updated December 2005. [View Article]
[6] “Implementation of the NPT Safeguards Agreement in the Islamic Republic of Iran,” International Atomic Energy Agency, November 15, 2004, p. 13, GOV/203/78.
[7] “Paper Details Work of Laser Research Center,” Ettela’at, in FBIS, ID FBIS-NES-93-076.
[8] “Implementation of the NPT Safeguards Agreement in the Islamic Republic of Iran,” International Atomic Energy Agency, November 15, 2004, p. 13.
[9] Charles D. Ferguson and Jack Boureston, “IAEA Puts Iranian Laser-Enrichment Technology in the Spotlight,” Jane’s Intelligence Review, July 2004, p. 41.
[10] P. Parvin, B. Sajad, K. Silakhor, M. Hooshvar, and Z. Zamanipour, “Molecular Laser Isotope Separation Versus Atomic Vapor Laser Isotope Separation,” Progress in Nuclear Energy, Vol 33 (4), pp. 331-345, 2004.
[11] For instance, in August 2004, an article was published describing the work done by AEOI scientists on the use of a pair of copper vapor lasers to investigate the temperature dependence of the small-signal gain and saturation intensity and output power of the laser at certain transition stages. See, S. Behrouzinia, R. Sadighi-Bonabi, P. Parvin, and M. Zand, “Temperature Dependence of the Amplifying Parameters of a Copper Vapor Laser,” Laser Physics, 14 (8) pp. 1050-1053, August 2004. Also see a July 2005 report that records the use of TEA- CO2 copper vapor lasers to develop “lidars” - a technique for range-resolved remote measurements; A.R.Bahrampour and A.A. Askari, “Fourier-wavelet regularized deconvolution (ForWaRD) for Lidar Systems Based on TEA-CO2 Laser,” Optics Communications, 257 (2006) 97-11.
[12] For a simple explanation of this issue, see Charles D. Ferguson and Jack Boureston, “IAEA Puts Iranian Laser-Enrichment Technology in the Spotlight,” Jane’s Intelligence Review, July 2004, p. 41.