On Line Enrichment Monitor (OLEM) UF6 Tests for 1.5" Sch40 SS Pipe, Revision 1
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
As global uranium enrichment capacity under international safeguards expands, the International Atomic Energy Agency (IAEA) is challenged to develop effective safeguards approaches at gaseous centrifuge enrichment plants while working within budgetary constraints. The “Model Safeguards Approach for Gas Centrifuge Enrichment Plants” (GCEPs) developed by the IAEA Division of Concepts and Planning in June 2006, defines the three primary Safeguards objectives to be the timely detection of: 1) diversion of significant quantities of natural (NU), depleted (DU) or low-enriched uranium (LEU) from declared plant flow, 2) facility misuse to produce undeclared LEU product from undeclared feed, and 3) facility misuse to produce enrichments higher than the declared maximum, in particular, highly enriched uranium (HEU). The ability to continuously and independently (i.e. with a minimum of information from the facility operator) monitor not only the uranium mass balance but also the 235U mass balance in the facility could help support all three verification objectives described above. Two key capabilities required to achieve an independent and accurate material balance are 1) continuous, unattended monitoring of in-process UF6 and 2) monitoring of cylinders entering and leaving the facility. The continuous monitoring of in-process UF6 would rely on a combination of load-cell monitoring of the cylinders at the feed and withdrawal stations, online monitoring of gas enrichment, and a high-accuracy net weight measurement of the cylinder contents. The Online Enrichment Monitor (OLEM) is the instrument that would continuously measure the time-dependent relative uranium enrichment, E(t), in weight percent 235U, of the gas filling or being withdrawn from the cylinders. The OLEM design concept combines gamma-ray spectrometry using a collimated NaI(Tl) detector with gas pressure and temperature data to calculate the enrichment of the UF6 gas within the unit header pipe as a function of time. The OLEM components have been tested on ORNL UF6 flow loop. Data were collected at five different enrichment levels (0.71%, 2.97%, 4.62%, 6.0%, and 93.7%) at several pressure conditions. The test data were collected in the standard OLEM N.4242 file format for each of the conditions with a 10-minute sampling period and then averaged over the span of constant pressures. Analysis of the collected data has provided enrichment constants that can be used for 1.5” stainless steel schedule 40 pipe measurement sites. The enrichment constant is consistent among all the wide range of enrichment levels and pressures used.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- AC05-00OR22725
- OSTI ID:
- 1257899
- Report Number(s):
- ORNL/LTR-2015/773; TRN: US1601498
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
ON-LINE MEASUREMENT SYSTEMS
HIGHLY ENRICHED URANIUM
SLIGHTLY ENRICHED URANIUM
DEPLETED URANIUM
URANIUM HEXAFLUORIDE
CENTRIFUGE ENRICHMENT PLANTS
PIPES
URANIUM 235
STAINLESS STEELS
ENRICHMENT
MONITORS
ISOTOPE SEPARATION
MONITORING
NAI DETECTORS
CYLINDERS
IAEA SAFEGUARDS
GAS CENTRIFUGES
TIME DEPENDENCE
GAMMA SPECTROSCOPY
MASS BALANCE
WEIGHT
MATERIAL BALANCE
DESIGN
DETECTION
SAMPLING
VERIFICATION