The Blend Down Monitoring System and Its Role for the HEU Transparency Program: Progress and Prospects

The paper discusses the Blend Down Monitoring System (BDMS) implemented at three highly enriched uranium (HEU) down blending facilities in Russia, namely, the Urals Electrochemical Integrated Enterprise at Novouralsk (installed February 1999), the Electrochemical Plant at Zelenogorsk (installed March 2003), and the Siberian Chemical Enterprise at Seversk (installed October 2004). The BDMS was implemented by the U.S. Department of Energy/National Nuclear Security Administration and the Russian State Atomic Energy Corporation “Rosatom” as part of the HEU Agreement. The 1993 HEU Purchase Agreement between the United States and the Russian Federation provides for the down blending of HEU from dismantled Russian nuclear weapons for use as nuclear fuel. The U.S. HEU Transparency Program ensures that the nonproliferation objectives of the Agreement are met. As part of that effort, the BDMS provides independent, continuous nondestructive analysis of the enrichment and fissile (235U) mass flow rate of uranium hexafluoride as it is down blended from HEU to low enriched uranium in Russia. In general, this paper describes the BDMS operational characteristics and technical installation specifications, the role of the BDMS for achieving the transparency objectives, the present operational status, and future plans.