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Nuclear Safeguards Education Portal
  

Nuclear Material Measurement Techniques and Equipment

NSSPI Students Braden Goddard and Chris Ryan with Dr. Paulo Peerani and the Active Well Coincidence Counter (AWCC) at the European Commission Joint Research Center (JRC) in Ispra, Italy.
NSSPI Students Braden Goddard and Chris Ryan with Dr. Paulo Peerani and the Active Well Coincidence Counter (AWCC) at the European Commission Joint Research Center (JRC) in Ispra, Italy. 

Nuclear material verification relies heavily upon sophisticated measurement techniques.  This equipment fall under two general categories:

Nondestructive Assay (NDA) is a measurement of the nuclear material content (or of the element or isotopic concentration) of an item without producing significant physical or chemical changes in the item.  Generally, it is carried out by observing the radiation emission from the item and by comparing that emission with calibration standards whose contents have been determined through destructive Analysis.

Destructive Analysis (DA) normally involves destruction of the physical form of the sample and could include taking of a representative sample or sample conditioning prior to analysis.

Below are several of the more common NDA instruments used for nuclear materials accountancy:

  • Active Well Neutron Coincidence Counter (He-3 tubes in poly and using AmLi source):  for measuring Pu and U quantities
  • Cerenkov Viewing Device: for distinguishing spent fuel from voidsin spent nuclear fuel storage pool, etc.
  • Fork detector: for measuring burnup and diversions of pins fromirradiated fuel assemblies (fission chambers and ion chambers)
  • Mobile FRAM system: for U and Pu isotopic measurements
  • HM-5: handheld assay probe for nuclear material detection and U, Pu attributes measurements

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