Standard Test Method for Nondestructive Assay of Radioactive Material by Tomographic Gamma Scanning

SIGNIFICANCE AND USE
The TGS provides a nondestructive means of mapping the attenuation characteristics and the distribution of the radionuclide content of items on a voxel by voxel basis. Typically in a TGS analysis a vertical layer (or segment) of an item will be divided into a number of voxels. By comparison, a segmented gamma scanner (SGS) can determine matrix attenuation and radionuclide concentrations only on a segment by segment basis.
It has been successfully used to quantify 238Pu, 239Pu, and 235U. SNM loadings from 0.5 g to 200 g of 239Pu (5, 6), from 1 g to 25 g of 235U (7), and from 0.1 to 1 g of 238Pu have been successfully measured. The TGS technique has also been applied to assaying radioactive waste generated by nuclear power plants (NPP). Radioactive waste from NPP is dominated by activation products (for example, 54Mn, 58Co, 60Co, 110mAg) and fission products (for example, 137Cs, 134Cs). The radionuclide activities measured in NPP waste is in the range from 3.7E+04 Bq to 1.0E+07 Bq. Some results of TGS application to non-SNM radionuclides can be found in the literature (8).
The TGS technique is well suited for assaying items that have heterogeneous matrices and that contain a non-uniform radionuclide distribution.
Since the analysis results are obtained on a voxel by voxel basis, the TGS technique can in many situations yield more accurate results when compared to other gamma ray techniques such as SGS.
In determining the radionuclide distribution inside an item, the TGS analysis explicitly takes into account the cross talk between various vertical layers of the item.
The TGS analysis technique uses a material basis set method that does not require the user to select a mass attenuation curve apriori, provided the transmission source has at least 2 gamma lines that span the energy range of interest.
A commercially available TGS system consists of building blocks that can easily be configured to operate the system in the SGS mode or in a far-field geometry.
...
SCOPE
1.1 This test method describes the nondestructive assay (NDA) of gamma ray emitting radionuclides inside containers using tomographic gamma scanning (TGS). High resolution gamma ray spectroscopy is used to detect and quantify the radionuclides of interest. The attenuation of an external gamma ray transmission source is used to correct the measurement of the emission gamma rays from radionuclides to arrive at a quantitative determination of the radionuclides present in the item.
1.2 The TGS technique covered by the test method may be used to assay scrap or waste material in cans or drums in the 1 to 500 litre volume range. Other items may be assayed as well.
1.3 The test method will cover two implementations of the TGS procedure: (1) Isotope Specific Calibration that uses standards of known radionuclide masses (or activities) to determine system response in a mass (or activity) versus corrected count rate calibration, that applies to only those specific radionuclides for which it is calibrated, and (2) Response Curve Calibration that uses gamma ray standards to determine system response as a function of gamma ray energy and thereby establishes calibration for all gamma emitting radionuclides of interest.
1.4 This test method will also include a technique to extend the range of calibration above and below the extremes of the measured calibration data.
1.5 The assay technique covered by the test method is applicable to a wide range of item sizes, and for a wide range of matrix attenuation. The matrix attenuation is a function of the matrix composition, photon energy, and the matrix density. The matrix types that can be assayed range from light combustibles to cemented sludge or concrete. It is particularly well suited for items that have heterogeneous matrix material and non-uniform radioisotope distributions. Measured transmission values should be available to permit valid attenuation corrections, but are not neede...

General Information

Status
Historical
Publication Date
31-Dec-2009
Technical Committee
Current Stage
Ref Project

Relations

Buy Standard

Standard
ASTM C1718-10 - Standard Test Method for Nondestructive Assay of Radioactive Material by Tomographic Gamma Scanning
English language
13 pages
sale 15% off
Preview
sale 15% off
Preview

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: C1718 − 10
Standard Test Method for
Nondestructive Assay of Radioactive Material by
1
Tomographic Gamma Scanning
This standard is issued under the fixed designation C1718; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope corrections, but are not needed for all volume elements in the
container, for example, if interpolation is justified.
1.1 This test method describes the nondestructive assay
(NDA) of gamma ray emitting radionuclides inside containers
1.6 The values stated in SI units are to be regarded as
using tomographic gamma scanning (TGS). High resolution
standard. No other units of measurement are included in this
gamma ray spectroscopy is used to detect and quantify the
standard.
radionuclidesofinterest.Theattenuationofanexternalgamma
1.7 This standard does not purport to address all of the
ray transmission source is used to correct the measurement of
safety concerns, if any, associated with its use. It is the
the emission gamma rays from radionuclides to arrive at a
responsibility of the user of this standard to establish appro-
quantitative determination of the radionuclides present in the
priate safety and health practices and determine the applica-
item.
bility of regulatory limitations prior to use.
1.2 The TGS technique covered by the test method may be
used to assay scrap or waste material in cans or drums in the 1
2. Referenced Documents
to500litrevolumerange.Otheritemsmaybeassayedaswell.
2
2.1 ASTM Standards:
1.3 The test method will cover two implementations of the
C1030TestMethodforDeterminationofPlutoniumIsotopic
TGS procedure: (1) Isotope Specific Calibration that uses
Composition by Gamma-Ray Spectrometry
standards of known radionuclide masses (or activities) to
C1128Guide for Preparation of Working Reference Materi-
determine system response in a mass (or activity) versus
als for Use in Analysis of Nuclear Fuel Cycle Materials
corrected count rate calibration, that applies to only those
C1490GuidefortheSelection,TrainingandQualificationof
specific radionuclides for which it is calibrated, and (2)
Nondestructive Assay (NDA) Personnel
Response Curve Calibration that uses gamma ray standards to
C1156Guide for Establishing Calibration for a Measure-
determine system response as a function of gamma ray energy
ment Method Used toAnalyze Nuclear Fuel Cycle Mate-
and thereby establishes calibration for all gamma emitting
rials
radionuclides of interest.
C1592Guide for Nondestructive Assay Measurements
1.4 This test method will also include a technique to extend C1673Terminology of C26.10 NondestructiveAssay Meth-
the range of calibration above and below the extremes of the ods
3
measured calibration data.
2.2 ANSI Standards:
1.5 The assay technique covered by the test method is ANSI N15.37Guide to the Automation of Nondestructive
applicable to a wide range of item sizes, and for a wide range Assay Systems for Nuclear Materials Control
of matrix attenuation. The matrix attenuation is a function of 4
2.3 Nuclear Regulatory Commission (NRC) Guides
the matrix composition, photon energy, and the matrix density.
NRC Guide 5.9Guidelines for Germanium Spectroscopy
The matrix types that can be assayed range from light
Systems for Measurement of Special Nuclear Material,
combustibles to cemented sludge or concrete. It is particularly
Revision 2, December 1983
well suited for items that have heterogeneous matrix material
and non-uniform radioisotope distributions. Measured trans-
mission values should be available to permit valid attenuation
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
1
ThistestmethodisunderthejurisdictionofASTMCommitteeC26onNuclear the ASTM website.
3
Fuel Cycle and is the direct responsibility of Subcommittee C26.10 on Non Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
Destructive Assay. 4th Floor, New York, NY 10036, http://www.ansi.org.
4
Current edition approved Jan. 1, 2010. Published February 2010. DOI: 10.1520/ AvailablefromU.S.NuclearRegulatoryCommission,Washington,DC20555-
C1718-10. 0001, http://nrc.gov.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
C1718 − 10
NRC Guide 5.53Qualification, Calibration, and Error Esti- 3.1.10 non-negative least squares (NNLS), n—constrained
mation Methods for Nondestructive Assay, Revisio
...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.