Nuclear Sites

7th of Tir Industries (Seventh of Tir, Hafte Tir or Haftom e Tir Industries)

Seventh of Tir Industries, located near Esfahan, is under the Defense Industries Organization and a subsidiary of the Ammunition and Metallurgy Industries Group (AMIG).  It is mainly involved in manufacturing rockets and missiles.  United Nations Security Council Resolution 1737 (2006) states that 7th of Tir is “widely recognized as being directly involved in the nuclear program.”

The company takes its name from an important date on the Iranian calendar – the 7th of Tir – on which a bomb exploded at the headquarters of Iran’s Islamic Republic Party on June 28, 1981, killing more than seventy officials.  A number of Iranian buildings or places now bear the name.

Prior to the 2003 suspension of Iran’s sensitive nuclear programs, 7th of Tir had responsibility for manufacturing several critical P1 centrifuge components under a contract with the centrifuge program.  This facility had some of the most sophisticated machining capabilities in Iran, achieved through overseas procurements of sophisticated machine tools and technology.

Whether it continues to make centrifuge components is uncertain, based on public information and reports by the International Atomic Energy Agency (IAEA).  Iran is not required under its comprehensive safeguards agreement to declare to the IAEA where it makes centrifuge components and thus there is little official information about centrifuge manufacturing in Iran.  However, 7th of Tir’s capabilities would have been a powerful motivation for the centrifuge program to continue contracting with this defense company to make sensitive centrifuge components.  It may therefore be making centrifuge components today.

Public information about the centrifuge-related activities at 7th of Tir relates to the period prior to Iran’s suspension of centrifuge activity in 2003.  Iran suspended its centrifuge manufacturing efforts for a time between late 2003 (when it also signed but did not ratify the Additional Protocol) and early February 2006, when it notified the IAEA that both its voluntary adherence to the Additional Protocol and its suspension of enrichment activity was over.  As part of these agreements, Iran revealed details about centrifuge manufacturing to the IAEA.

Under contract with the centrifuge program, DIO specialists at 7th or Tir made over twenty critical rotating components of the P1 centrifuge rotor.  According to Vienna-based diplomats present at technical briefings by IAEA officials, this facility was originally contracted in about 2001 to make 10,000 sets of these centrifuge components.

The 7th of Tir Steel Complex appears in satellite imagery as a large, gated and guarded site for missile production.  Reports indicate that centrifuge components were manufactured in several unidentified facilities within the 7th of Tir site, including a forgings workshop, a flow forming workshop, a machine shop, and a quality control laboratory.  The components were made in these facilities on high precision U.S. and European machine tools and measuring equipment.

Prior to the 2003 suspension of centrifuge manufacturing, 7th or Tir had not finished making all the components it had agreed to produce.  During the suspension, to prevent IAEA monitoring of what is a sensitive military site, Iran moved key centrifuge manufacturing equipment and components to Natanz and other sites.  It is unknown if after the end of the suspension, these items were returned to 7th or Tir, or if production was resumed on these components there. However, it is a reasonable assumption that after the suspension ended, it finished making the rest of them.

This site manufactured one of the IR-1 centrifuge’s most sensitive parts, its bellows—a thin-walled cylindrical part—made from grade 300 or 350 maraging steel. Each IR-1 centrifuge requires three bellows.  Iran illicitly purchased 67 tonnes of this super strong steel in the United Kingdom in the 1990s.  The material was in the shape of bar (about 100 millimeter diameter).  Normally, Iran would have wanted tubes, which can then be flow formed into thin-walled bellows. Maraging steel is a sensitive commodity, whose purchase is controlled by suppliers, which complicates Iran’s ability to buy it.  Iran may have found it easier to obtain if it asked for rods.  But the rod shape complicates the production of bellows.  Iranian technicians reportedly had to first use a hot lance to pierce the rod and then machine out the center into a tube.  This tube is then thinned to a wall thickness of only one millimeter on a specialized, precision flow-forming machine.  7th of Tir used a flow forming machine to do the thinning that it had obtained many years ago from the now defunct German firm Leifeld.  In total, 7th of Tir had four Leifeld flow forming machines, although only one was used to make bellows. 

Because this process of making bellows from bar is very wasteful, 67 tonnes of maraging steel is estimated as sufficient for approximately 36,000- 45,000 bellows.  Since each IR-1 centrifuge requires three bellows, Iran could make enough for some 12,000-15,000 centrifuges from this one order of maraging steel. 

Iran may have obtained additional maraging steel in the last several years.  Alternatively, it may have learned to recycle some of the large quantities of maraging steel scrap generated while making bellows. Most analysts do not believe Iran can make 300 or 350 grade maraging steel.

The U.S. Treasury Department added 7th of Tir Industries to the Specially Designated Nationals (SDN) list in 2008.  Britain, Japan, and the European Union have all listed 7th of Tir as a company of proliferation concern.

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site imagery

Date: Sep 08, 2004
Photo Type: Satellite