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Title: Isotopic Composition Measurements Using Ratio Based Method


This is a training course and is a part of the non-destructive assay for the international safeguards series.

  1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA), Office of Defense Nuclear Nonproliferation (NA-20)
OSTI Identifier:
Report Number(s):
DOE Contract Number:
Resource Type:
Technical Report
Country of Publication:
United States

Citation Formats

Vo, Duc Ta. Isotopic Composition Measurements Using Ratio Based Method. United States: N. p., 2017. Web. doi:10.2172/1392892.
Vo, Duc Ta. Isotopic Composition Measurements Using Ratio Based Method. United States. doi:10.2172/1392892.
Vo, Duc Ta. 2017. "Isotopic Composition Measurements Using Ratio Based Method". United States. doi:10.2172/1392892.
title = {Isotopic Composition Measurements Using Ratio Based Method},
author = {Vo, Duc Ta},
abstractNote = {This is a training course and is a part of the non-destructive assay for the international safeguards series.},
doi = {10.2172/1392892},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2017,
month = 9

Technical Report:

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  • This report addresses the feasibility of the laboratory measurements of isotopic ratios for selected trace constituents in irradiated nuclear-grade graphite, based on the results of a proof-of-principal experiment completed at Pacific Northwest National Laboratory (PNNL) in 1994. The estimation of graphite fluence through measurement of isotopic ratio changes in the impurity elements in the nuclear-grade graphite is referred to as the Graphite Isotope Ratio Method (GIRM). Combined with reactor core and fuel information, GIRM measurements can be employed to estimate cumulative materials production in graphite moderated reactors. This report documents the laboratory procedures and results from the initial measurements ofmore » irradiated graphite samples. The irradiated graphite samples were obtained from the C Reactor (one of several production reactors at Hanford) and from the French G-2 Reactor located at Marcoule. Analysis of the irradiated graphite samples indicated that replicable measurements of isotope ratios could be obtained from the fluence sensitive elements of Ti, Ca, Sr, and Ba. While these impurity elements are present in the nuclear-grade graphite in very low concentrations, measurement precision was typically on the order of a few tenths of a percent to just over 1 percent. Replicability of the measurements was also very good with measured values differing by less than 0.5 percent. The overall results of this initial proof-of-principal experiment are sufficiently encouraging that a demonstration of GIRM on a reactor scale basis is planned for FY-95.« less
  • The main objective of this project was to continue research to develop carbon cycle relationships related to the land biosphere based on remote measurements of atmospheric CO2 concentration and its isotopic ratios 13C/12C, 18O/16O, and 14C/12C. The project continued time-series observations of atmospheric carbon dioxide and isotopic composition begun by Charles D. Keeling at remote sites, including Mauna Loa, the South Pole, and eight other sites. Using models of varying complexity, the concentration and isotopic measurements were used to study long-term change in the interhemispheric gradients in CO2 and 13C/12C to assess the magnitude and evolution of the northern terrestrialmore » carbon sink, to study the increase in amplitude of the seasonal cycle of CO2, to use isotopic data to refine constraints on large scale changes in isotopic fractionation which may be related to changes in stomatal conductance, and to motivate improvements in terrestrial carbon cycle models. The original proposal called for a continuation of the new time series of 14C measurements but subsequent descoping to meet budgetary constraints required termination of measurements in 2007.« less
  • The objective of this project was to perform CO 2 data syntheses and modeling activities to address two central questions: 1) how much has the seasonal cycle in atmospheric CO 2 at northern high latitudes changed since the 1960s, and 2) how well do prognostic biospheric models represent these changes. This project also supported the continuation of the Scripps time series of CO 2 isotopes and concentration at ten baseline stations distributed globally.
  • When uranium hexafluoride is admitted to an isotopic mass spectrometer, the resultant ratio of U/sup 235/ to U/sup 238/ i s biased because of a phenomenon called memory. All mass spectrometer procedures must in some manner correct for this bias. An interpolative method was developed for the isotopic analysis of production samples, calibration of standard materials, and for the measurement of separation factors where precision and accuracy are of paramount importance. The interpolative procedure reduces the effect of memory to a negligible amount and at the same time compensates for, or eliminates, other sources of error. (auth)