5.1 Plutonium and uranium mixtures are used as nuclear reactor fuels. For use as a nuclear reactor fuel, the material must meet certain criteria for combined uranium and plutonium content, effective fissile content, and impurity content as described in Specifications C757 and C833. After dissolution using one of the procedures described in this practice, the material is assayed for plutonium and uranium to determine if the content is correct as specified by the purchaser.

5.2 Unique plutonium materials, such as alloys, compounds, and scrap metals, are typically dissolved with various acid mixtures or by fusion with various fluxes. Many plutonium salts are soluble in hydrochloric acid. One or more of the procedures included in this practice may be effective for some of these materials; however their applicability to a particular plutonium material shall be verified by the user.

1.1 This practice is a compilation of dissolution techniques for plutonium materials that are applicable to the test methods used for characterizing these materials. Dissolution treatments for the major plutonium materials assayed for plutonium or analyzed for other components are listed. Aliquots of the dissolved samples are dispensed on a weight basis when one of the analyses must be highly reliable, such as plutonium assay; otherwise they are dispensed on a volume basis.

1.2 Procedures in this practice are intended for the dissolution of plutonium metal, plutonium oxide, and uranium-plutonium mixed oxides. Aliquots of dissolved samples are analyzed using test methods, such as those developed by Subcommittee C26.05 on Methods of Test, to demonstrate compliance with applicable requirements. These may include product specifications such as Specifications C757 and C833.

1.3 One or more of the procedures in this practice may be applicable to unique plutonium materials, such as alloys, compounds, and scrap materials. The user must determine the applicability of this practice to such materials.

1.4 The treatments, in order of presentation, are as follows:

Procedure Number

Procedure Title

Section

1

Dissolution of Plutonium Metal with Hydrochloric Acid at Room Temperature

9

2

Dissolution of Plutonium Metal with Hydrochloric Acid and Heating

10

3

Dissolution of Plutonium Metal with Sulfuric Acid

11

4

Dissolution of Plutonium Oxide and Uranium-Plutonium Mixed
 Oxide by the Sealed-Reflux Technique

12

5

Dissolution of Plutonium Oxide and Uranium-Plutonium Mixed Oxides by Sodium Bisulfate Fusion

13

6

Dissolution of Uranium-Plutonium Mixed Oxides and Low-Fired Plutonium Oxide in Beakers

14

7

Open-Vessel (with Reflux Condenser) Dissolution of Plutonium Oxide Powder

15

8

Open-Vessel (with Reflux Condenser) Dissolution of Mixed Oxide Powder

16

9

Closed-Vessel Hot Block Dissolution of Plutonium Oxide Powder

17

10

Open-Vessel (with Reflux Condenser) Dissolution of Mixed Oxide Pellets

18

1.5 The values stated in SI units are to be regarded as standard. Values in parentheses (non-SI units), where provided, are for information only and are not considered standard.

1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.