Laser and Centrifuge Enrichment

Olli Heinonen Belfer Center for Science and International Affairs Harvard Kennedy School 3 November, 2013

Path to Nuclear Weapon Capability

Nuclear weapons programs took place parallel to civilian programs.

Nuclear power alone is not a stepping stone to weapon capability, but mastering of sensitive technologies such as the uranium enrichment is

Nuclear know-how: technologies cannot be un-invented and special skills fade away slowly.

Uranium Enrichment Processes

Diffusion techniques - Gaseous diffusion (US, UK, France, Russia) - Thermal diffusion

Gas centrifuge techniques Laser techniques

- Atomic vapor laser isotope separation (AVLIS) - Molecular laser isotope separation (MLIS) - Separation of Isotopes by Laser Excitation (SILEX)

Other techniques - Aerodynamic processes (South African nuclear weapons program) - Electromagnetic isotope separation (Manhattan project, Iraq) - Chemical methods - Plasma separation

Nuclear Energy Is for Dual Use Technology

The overlap between the equipment, knowledge and materials required to develop nuclear weapons and to conduct civilian nuclear research or develop nuclear defense limits the effectiveness of verification measures and complicates information acquisition and analysis .

Known Enrichment Facilities

Argentina, Brazil, China, France, Germany, India, Iran, Japan, The Netherlands, North Korea, Pakistan, Russia, The United Kingdom, The United States

AVLIS uses tuned lasers to separate isotopes of uranium using selective ionization of U-235 atoms, but not other uranium isotopes. First a pump laser (E.g. Nd-YAG) converts electrical energy into light energy, which energy “pumps,” the AVLIS process laser. The process laser ( dye laser), in turn, provides the specific frequency light needed to photoionize U235 vapor in the AVLIS process.

Atomic Vapor Laser Isotope Separation (AVLIS)

AVLIS uses tuned lasers to separate isotopes of uranium using selective ionization of U-235 atoms, but not other uranium isotopes. In 2001, average 235U concentration at the collectors reportedly was 4.5%, and collector current reached 6-8 mA. The collectors are 0.48 m long, and the reported product rate was 3-5 grams per hour. http://www.imp.kiae.ru/sciencelife/imp_2001_txt.htm

Atomic Vapor Laser Isotope Separation (AVLIS)

MLIS uses infrared lasers to excite in UF6 a U-235 atom. A second laser then frees a fluorine atom creating uranium pentafluorine, which then precipitates from the gas.

Molecular Laser Isotope Separation (MLIS)

Separation of Isotopes by Laser Excitation (SILEX)

Technical details of the SILEX have not been disclosed, but the process uses UF6 in a carrier gas, where U-235 atoms are selectively excited with a pulsed CO2 laser and then drawn to a collector. GE-Hitachi Global Laser Enrichment LLC, NC, USA.

• First suggestions for isotope separation in 1919 (Aston & Lindeman). •Jesse Beams separated chlorine isotopes in 1934. • Unsuccesful attempts in Manhattan Project. • German POWs including Gernot Zippe developed centrifuges in Russia. • Germany, the Netherlands and the UK worked with centrifuges from 1950’s. • Acquisition of technology from the black markets emerges in 1980’s (Pakistan)

About the History of Gas Centrifuges

Jesse Beams

Gernot Zippe

Argentina, Brazil, China, France, Germany, India, Iran, Japan, the Netherlands, North Korea, Pakistan, Russia, the United Kingdom, and the United States

Gas Ultra Centrifuge Enrichment

Gas Ultra Centrifuges

Enrichment factor P-2 1.17 UF6 Feed rate P-1 13 gr/hr UF6 P-2 70 gr/hr UF6

Gas Ultra Centrifuges

Rotor Dia cm Height m SWU kg/yr P-1 aluminum 10 2 > 2 P-2 maraging steel 15 1 > 5 TC10 maraging steel 15 3.2 > 20 TC12 carbon fiber 20 3 40 AC-100 carbon fiber 60 12 330

The IAEA Follows Inventories and Flow of Material

Views of Cascade Halls

Production of Weapons Grade Material

• Produce of HEU directly from NU, LEU or 20% U-235 (or higher). • Divert of declared NU,LEU, or 20% U-235 (or higher) for the enrichment elsewhere. • Produce LEU in excess of declared amounts for the enrichment elsewhere.

Enrichment Effort

• A 1300 Mwe LWR requires 25 tons 3.75 % uranium annually. This requires 210 tons uranium and 120000 SWUkg/yr. • 1 significant quantity (SQ) requires 5000-5500 SWUkg/yr effort, if natural uranium feed.

•Monthly interim inspections for flow verification - Feed, product, and tails cylinders receipt and shipment verification, -Auditing of accountancy records and reports

• Annual Physical Inventory Verification -Verification of inventory including the hold-up in process. - Material balance evaluation

• Unannounced inspections -Detect undeclared material and operations

•Detection goals -25 kg U-235 in HEU , one month -75 kg U-235 in LEU, one year

IAEA Inspection Scheme

IAEA Verification Measures

• Visual observation - Detect presence of unreported Feed/With drawal equipment within cascade areas. - Detect piping changes indicative of connecting cascades in series. • NDA measurements on header piping –Cascade Enrichment Header Monitor (CEMO) to detect HEU production. - Other equipment under development. • Take UF6 samples from cascade • Take environmental samples

IAEA Verification Measures

• Weights of UF6 Cylinders by a load-cell •UF6 Enrichment Measurements - by Gamma Ray NDA for gross and partial defect tests –sampling and DA for bias defect tests •Maintain continuity of knowledge - by surveillance and - seals

Why the Lasers are Controversial?

A key concern is that the high efficiency of a laser enrichment process: - would reduce energy requirements, - allowing a uranium enrichment plant to be smaller , -making them harder to detect using satellite imagery, and -relying in indigenous production of components. .

Reference/Reading Material

Laser Enrichment Methods (AVLIS AND MLIS), http://pbadupws.nrc.gov/docs/ML1204/ML12045A051.pdf Alexander Glaser, Characteristics of the Gas Centrifuge for Uranium Enrichment and Their Relevance for Nuclear Weapon Proliferation (corrected), Science and Global Security, 16:1–25, 2008. Simon Henderson and Olli Heinonen, Nuclear Iran, A Glossary of Terms, Policy Focus 121 , August 2012. Philip Casey Durst, Brent McGinnis , James Morgan and Michael Whitaker, Safeguards Guidance for Designers of Commercial Nuclear Facilities – International Safeguards Requirements for Uranium Enrichment Plants. EXT-09-16907, October 2009.