Confirmatory measurements of UF/sub 6/ using the neutron self-interrogation method
A passive neutron counting method has been developed for measurement of the /sup 235/U mass in Model 5A cylinders of UF/sub 6/. The unique neutronic properties of UF/sub 6/ containing highly enriched uranium (HEU) permit /sup 235/U assay using only passive neutron counting. The sample effectively assays itself by self-interrogation. Shipped from enrichment plants and received at fuel fabrication and conversion facilities, 5A UF/sub 6/ cylinders hold up to approx.17 kg of /sup 235/U each. Field measurements at the Portsmouth Gaseous Diffusion Plant (GDP) showed an average assay accuracy of 6.8% (1sigma) for 44 cylinders with enrichments from 6 to 98% and with a range of fill heights. Further measurements on 38 cylinders containing 97%-enriched material yielded an accuracy of 2.8% (1sigma). Typical counting times for these measurements were less than 5 min. An in-plant instrument for receipts confirmation measurements of 5A UF/sub 6/ cylinders has been developed for the Savannah River Plant. The Receipts Assay Monitor (RAM) is currently being tested and calibrated. It is designed to confirm declared fissile mass in all incoming 5A cylinders containing HEU in the form of UF/sub 6/. One of the computer-controlled features is a removable cadmium liner for the sample cavity. The liner allows a sample fill-height correction, which significantly improves assay accuracy.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 5466412
- Report Number(s):
- LA-UR-85-2567; CONF-850765-22; ON: DE85015752
- Resource Relation:
- Conference: 26. annual meeting of the Institute of Nuclear Materials Management, Albuquerque, NM, USA, 21 Jul 1985; Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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Direct fissile assay of highly enriched UF/sub 6/ using random self-interrogation and neutron coincidence response
Direct fissile assay of enriched uranium using random self-interrogation and neutron coincidence response
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37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
URANIUM 235
COINCIDENCE METHODS
URANIUM HEXAFLUORIDE
ACCOUNTING
INVENTORIES
ACTINIDE COMPOUNDS
ACTINIDE ISOTOPES
ACTINIDE NUCLEI
ALPHA DECAY RADIOISOTOPES
COUNTING TECHNIQUES
EVEN-ODD NUCLEI
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
HEAVY NUCLEI
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
MINUTES LIVING RADIOISOTOPES
NUCLEI
RADIOISOTOPES
URANIUM COMPOUNDS
URANIUM FLUORIDES
URANIUM ISOTOPES
YEARS LIVING RADIOISOTOPES
055001* - Nuclear Fuels- Safeguards
Inspection
& Accountability- Technical Aspects
400101 - Activation
Nuclear Reaction
Radiometric & Radiochemical Procedures