ASTM C1718-10
Standard Test Method for Nondestructive Assay of Radioactive Material by Tomographic Gamma Scanning

Standard No.

ASTM C1718-10

Release Date

2010

Published By

American Society for Testing and Materials (ASTM)

Status

Be replaced

Replace By

ASTM C1718-10(2019)

Latest

ASTM C1718-10(2019)

Scope

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.

The TGS provides 3-dimensional maps of gamma ray attenuation and radionuclide concentration within an item that can be used as a diagnostic tool.

Item preparation is limited to avoiding large quantities of heavily attenuating materials (such as lead shielding) in order to allow sufficient transmission through the container and the matrix.

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 th......

ASTM C1718-10 Referenced Document

• ASTM C1030 Standard Test Method for Determination of Plutonium Isotopic Composition by Gamma-Ray Spectrometry
• ASTM C1128 Standard Guide for Preparation of Working Reference Materials for Use in the Analysis of Nuclear Fuel Cycle Materials
• ASTM C1156 Standard Guide for Establishing Calibration for a Measurement Method Used to Analyze Nuclear Fuel Cycle Materials
• ASTM C1490 Standard Guide for the Selection, Training and Qualification of Nondestructive Assay (NDA) Personnel
• ASTM C1592 Standard Guide for Nondestructive Assay Measurements
• ASTM C1673 Standard Terminology of C26.10 Nondestructive Assay Methods

ASTM C1718-10 history

• 2019 ASTM C1718-10(2019) Standard Test Method for Nondestructive Assay of Radioactive Material by Tomographic Gamma Scanning
• 2010 ASTM C1718-10 Standard Test Method for Nondestructive Assay of Radioactive Material by Tomographic Gamma Scanning