Nuclear Non-proliferation Import and Export Control Regulations — A.2.4
otected 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 plants. A.2.4.2.4 UF 6 mass spectrometers with ion sources Especially designed or prepared mass spectrometers capable of taking on-line samples from UF 6 gas streams and having all of the following characteristics: (a) the capability of measuring ions of 320 atomic mass units or greater with a resolution of better than 1 part in 320; (b) ion sources made of or protected by nickel, nickel-copper alloys with a nickel content of 60% by weight or more, or nickel-chrome alloys; (c) electron bombardment ionization sources; and (d) a collector system suitable for isotopic analysis. A.2.4.2.5 Frequency changers Frequency changers (also known as converters or inverters) especially designed or prepared to supply motor stators within the meaning of paragraph A.2.4.1.2(d), or parts, components and sub-assemblies of such frequency changers, having both of the following characteristics: (a) a multiphase frequency output of 600 Hz or greater; and (b) high stability (with frequency control better than 0.2%). A.2.4.3 Especially designed or prepared assemblies and components for use in gaseous diffusion enrichment, including: A.2.4.3.1 Gaseous diffusion barriers and barrier materials (a) especially designed or prepared thin, porous filters, with a pore size of 10 nm to 100 nm, a thickness of 5 mm or less, and for tubular forms, a diameter of 25 mm or less, made of metallic, polymer or ceramic materials resistant to corrosion by UF 6 ; and (b) especially prepared compounds or powders for the manufacture of such filters. Such compounds and powders include nickel or alloys containing 60% by weight or greater nickel, aluminium oxide, or UF 6 -resistant fully fluorinated hydrocarbon polymers having a purity of 99.9% by weight or greater, a particle size less than 10 µm, and a high degree of particle size uniformity, which are especially prepared for the manufacture of gaseous diffusion barriers. A.2.4.3.2 Diffuser housings Especially designed or prepared hermetically sealed cylindrical vessels for containing the gaseous diffusion barrier, made of or protected by UF 6 -resistant materials. A.2.4.3.3 Compressors and gas blowers Especially designed or prepared compressors and gas blowers with a suction volume capacity of 1 m 3 /min or more of UF 6 and a discharge pressure of up to 500 kPa, designed for long-term operation in the UF 6 environment, as well as separate assemblies of such compressors and gas blowers. These compressors and gas blowers have a pressure ratio of 10:1 or less and are made of or protected by materials resistant to UF 6 . A.2.4.3.4 Rotary shaft seals Especially designed or prepared vacuum seals, with seal feed and seal exhaust connections, for sealing the shaft connecting the compressor or the gas blower rotor with the driver motor so as to ensure a reliable seal against in-leaking of air into the inner chamber of the compressor or gas blower, which is filled with UF 6 . Such seals are normally designed for a buffer gas in-leakage rate of less than 1 000 cm 3 /min. A.2.4.3.5 Heat exchangers for cooling UF 6 Especially designed or prepared heat exchangers made of or protected by UF 6 -resistant materials and intended for a leakage pressure change rate of less than 10 Pa/hour under a pressure difference of 100 kPa. A.2.4.4 Especially designed or prepared auxiliary systems, equipment and components for use in gaseous diffusion enrichment, including: A.2.4.4.1 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 (or cold traps) or pumps used to remove UF 6 from the enrichment process