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U.S. Department of Energy
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Lower Limit of Detection (LLD) Determination for PFP Residues Segmented Gamma Scan Assay System (SGSAS)

Technical Report ·
DOI:https://doi.org/10.2172/808108· OSTI ID:808108

The Plutonium Finishing Plant (PFP) facility performs waste characterization measurements for disposal of transuranic waste (TRU) at the Waste Isolation Pilot Plant (WIPP). The WIPP's performance assessment requires monitoring and tracking of the following ten radionuclides in the waste that is accepted and disposed of at the WIPP facility. Activities and mass values must be reported for: {sup 241}Am, {sup 238}Pu, {sup 239}Pu, {sup 240}Pu, {sup 242}Pu, {sup 233}U, {sup 234}U, {sup 238}U, {sup 90}Sr and {sup 137}Cs on a payload container basis. PFP reports the activity and mass of these radionuclides when positively identified in any waste container. In situations where a WIPP radionuclide is not positively identified on a PFP assay, PFP either reports a ''zero'', indicating the nuclide was not positively identified in the waste assay and is not identified by the acceptable knowledge (AK), or ''<LLD'' (less than the lower limit of detection) indicating the nuclide exists in the AK, but was not positively identified above its lower limit of detection or the minimum detectable activity (MDA). The definition of ''positive'' identification requires some explanation since not all of the radionuclides listed above can be directly quantified on PFP's assay system, the Room 170 Segmented Gamma Scan Assay System (SGSAS), and some nuclides are better characterized via isotopic ratios rather than by direct quantification. The current system, the Room 170 SGSAS, identifies and quantifies {sup 239}Pu, {sup 233}U, {sup 238}U, {sup 241}Am and {sup 137}Cs, and also calculates the relative isotopic ratios for the plutonium isotopes, {sup 241}Am, {sup 235}U, and {sup 237}Np.

Research Organization:
FH (US)
Sponsoring Organization:
USDOE Office of Environmental Management (EM) (US)
DOE Contract Number:
AC06-96RL13200
OSTI ID:
808108
Report Number(s):
HNF-11067, Rev.0; EDT-626639
Country of Publication:
United States
Language:
English