Nuclear Non-proliferation Import and Export Control Regulations — A.2.4
homogeneity of the material of the magnet is specially called for; or (2) active magnetic bearings especially designed or prepared for use in gas centrifuges; (b) bearings/dampers: especially designed or prepared bearings comprising a pivot/cup assembly mounted on a damper. The pivot is normally a hardened steel shaft with a hemisphere at one end with a means of attachment to the bottom cap described in paragraph A.2.4.1.1.(e) at the other. The shaft may however have a hydrodynamic bearing attached. The cup is pellet-shaped with a hemispherical indentation in one surface. These components are often supplied separately to the damper; (c) molecular pumps: especially designed or prepared cylinders having internally machined or extruded helical grooves and internally machined bores. Typical dimensions are as follows: 75 mm to 650 mm internal diameter, 10 mm or more wall thickness, with the length equal to or greater than the diameter. The grooves are typically rectangular in cross-section and 2 mm or more in depth; (d) motor stators: especially designed or prepared annular stators for high speed multiphase AC hysteresis (or reluctance) motors for synchronous operation within a vacuum at a frequency of 600 Hz or greater and a power of 40 VA or greater. The stators may consist of multiphase windings on a laminated low-loss iron core comprised of thin layers typically 2 mm thick or less; (e) centrifuge housing or recipients: components especially designed or prepared to contain the rotor tube assembly of a gas centrifuge. The housing consists of a rigid cylinder of wall thickness up to 30 mm with precision-machined ends to locate the bearings and with one or more flanges for mounting. The machined ends are parallel to each other and perpendicular to the cylinder’s longitudinal axis to within 0.05° or less. The housing may also be a honeycomb-type structure to accommodate several rotor assemblies; and (f) scoops: especially designed or prepared tubes for the extraction of UF 6 gas from within the rotor tube by a Pitot tube action (that is, with an aperture facing into the circumferential gas flow within the rotor tube, for example by bending the end of a radially disposed tube) and capable of being fixed to the central gas extraction system. A.2.4.2 Especially designed or prepared auxiliary systems, equipment and components for gas centrifuge enrichment plants, including the following: A.2.4.2.1 Feed systems or product and tails withdrawal systems Especially designed or prepared process systems or equipment for enrichment plants, made of or protected by materials resistant to corrosion by UF 6 including (a) feed autoclaves, ovens or systems used for passing UF 6 to the enrichment process; (b) desublimers, cold traps or pumps used to remove UF 6 from the enrichment process for subsequent transfer upon heating; (c) solidification or liquefaction stations used to remove UF 6 from the enrichment process by compressing and converting UF 6 to a liquid or solid form; and (d) product and tails stations used for transferring UF 6 into containers. A.2.4.2.2 Machine header piping systems Especially designed or prepared piping systems and header systems for handling UF 6 within the centrifuge cascades. The piping system is normally of the triple header type with each centrifuge connected to each of the headers. There is thus a substantial amount of repetition in its form. It is wholly made of or protected by UF 6 -resistant materials and is fabricated to very high vacuum and cleanliness standards. A.2.4.2.3 Special shut-off and control valves (a) shut-off valves especially designed or prepared to act on the feed, product or tails UF 6 gas streams of a gas centrifuge; or (b) bellows-sealed valves, manual or automated shut-off or control, made of or protected by materials resistant to corrosion by UF 6 , with an inside diameter of 10 mm to 160 mm, especially designed or prepared for use in main or auxiliary systems of gas centrifuge enrichment plan