Measurement Methodology of the Fissile Mass Flow Monitor for the HEU Transparency Implementation Instrumentation in Russia
The highly enriched uranium (HEU) Transparency Agreement between the U.S. and Russian Federation (RF) requires implementation of transparency measures in the Russian facilities that are supplying product low enriched uranium (LEU) to the U.S. from down blended weapon-grade HEU material. To satisfy the agreement's non-proliferation objectives, the U.S. DOE is implementing the fissile mass flow monitor (FMFM) instrumentation developed by Oak Ridge National Laboratory. The FMFM provides unattended non-intrusive measurements of {sup 235}U mass flow of the uranium hexafluoride (UF{sub 6}) gas in the process lines of HEU, the LEU blend stock, and the resulting lower assay product LEU (P-LEU) that is used for U.S. reactors. The instrumentation continuously traces the HEU flow through the blending point to the product LEU, enabling the U.S. to verify HEU material down blending. The FMFM relies on producing delayed gamma rays emitted from fission fragments carried by the UF{sub 6} flow. A thermalized californium-252 ({sup 252}Cf)-neutron source placed in an annular sleeve filled with moderator material that surrounds the pipe is modulated by a neutron absorbent shutter to induce fission in UF{sub 6}. For this technique to be effectively applicable the average range of resulting fission fragments in the UF{sub 6} gas must be smaller than the pipe diameter. The fission fragment range can be very large in low-density materials. Therefore, a methodology has been developed to determine the fission fragment range and its distribution to assess the fraction of the fission fragments that will remain in the flow; this methodology is the primary topic of discussions in this paper.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- AC05-00OR22725
- OSTI ID:
- 788628
- Report Number(s):
- P01-111150; TRN: US0200532
- Resource Relation:
- Conference: Institute of Nuclear Materials Management, Indian Wells, CA (US), 07/15/2001--07/19/2001; Other Information: PBD: 28 Jun 2001
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
CALIFORNIUM 252
HIGHLY ENRICHED URANIUM
RADIATION MONITORS
NUCLEAR MATERIALS MANAGEMENT
RUSSIAN FEDERATION
URANIUM HEXAFLUORIDE
USA
SLIGHTLY ENRICHED URANIUM
GAMMA DETECTION
ON-LINE MEASUREMENT SYSTEMS