ASTM International

Standard Test Method for Nondestructive Assay of Plutonium in Scrap and Waste by Passive Neutron Coincidence Counting
 N C1207

Annotation

This test method describes the nondestructive assay of scrap or waste for plutonium content using passive thermalneutron coincidence counting. This test method provides rapid results and can be applied to a variety of carefully sorted materials in containers as large as several thousand liters in volume. The test method applies to measurements of 238Pu, 240Pu, and 242Pu and has been used to assay items whose total plutonium content ranges from 10 mg to 6 kg (1).2

This test method requires knowledge of the relative abundances of the Pu isotopes to determine the total Pu mass (Test Method C1030).

This test method may not be applicable to the assay of scrap or waste containing other spontaneously fissioning nuclides.

This test method may give biased results for measurements of containers that include large amounts of hydrogenous materials.

The techniques described in this test method have been applied to materials other than scrap and waste (2, 3).

This test method assumes the use of shift-register-based coincidence technology (4).

Several other techniques that are often encountered in association with passive neutron coincidence counting exist These include neutron multiplicity counting (5, 6, Test Method C1500), add-a-source analysis for matrix correction (7), flux probes also for matrix compensation, cosmic-ray rejection (8) to improve precision close to the detection limit, and alternative data collection electronics such as list mode data acquisition. Passive neutron coincidence counting may also be combined with certain active interrogation schemes as in Test Methods C1316 and C1493. Discussions of these established techniques are not included in this method.