Значение и использование

Plutonium dioxide is used in mixtures with uranium dioxide as a nuclear-reactor fuel. In order to be suitable for this purpose, the material must meet certain criteria for plutonium content, isotopic composition, and impurity content. These test methods are designed to show whether or not a given material meets the specifications for these items as described in Specification C757.

An assay is performed to determine whether the material has the minimum plutonium content specified on a dry weight basis.

Determination of the isotopic content of the plutonium in the plutonium dioxide powder is made to establish whether the effective fissile content is in compliance with the purchaser's specifications.

Impurity content is determined to ensure that the maximum concentration limit of certain impurity elements is not exceeded. Determination of impurities is also required for calculation of the equivalent boron content (EBC).

Область применения

1.1 These test methods cover procedures for the chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade plutonium dioxide powders and pellets to determine compliance with specifications.

1.2 The analytical procedures appear in the following order:

Sections Plutonium Sample Handling 8 to 10 Plutonium by Controlled-Potential Coulometry Plutonium by Ceric Sulfate Titration Plutonium by Amperometric Titration with Iron(II) Plutonium by Diode Array   Spectrophotometry Nitrogen by Distillation Spectrophotometry Using Nessler
Reagent 11 to 18 Carbon (Total) by Direct Combustion–Thermal Conductivity 19 to 30 Total Chlorine and Fluorine by Pyrohydrolysis 31 to 38 Sulfur by Distillation Spectrophotometry 39 to 47 Plutonium Isotopic Analysis by Mass Spectrometry Rare Earth Elements by Spectroscopy 48 to 55 Trace Elements by Carrier–Distillation Spectroscopy 56 to 63 Impurities by ICP-AES Impurity Elements by Spark-Source Mass Spectrography64 to 70 Moisture by the Coulometric Electrolytic Moisture Analyzer71 to 78 Total Gas in Reactor-Grade Plutonium Dioxide Pellets79 to 86 Plutonium-238 Isotopic Abundance by Alpha Spectrometry Americium-241 in Plutonium by Gamma-Ray Spectrometry Rare Earths By Copper Spark-Spectroscopy87 to 96 Plutonium Isotopic Analysis by Mass Spectrometry97 to 105 Oxygen-To-Metal Atom Ratio by Gravimetry106 to 114

1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are for information only.

1.4 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. For specific precautionary statements, see Sections 6, 15, 24, 111, and 52.9 and 101.5.1 .

8.1 This test method covers the conditions necessary to preserve the integrity of plutonium dioxide samples. Conditions listed here are directed toward the analytical chemist. However, they are just as applicable to any group handling the material.

11.1 This test method covers the determination of 5 to 100 μg/g of nitride nitrogen in 1-g samples of nuclear-grade plutonium dioxide.

19.1 This test method covers the determination of 10 to 200 μg of residual carbon in nuclear-grade plutonium dioxide.

31.1 This test method covers the determination of 5 to 100 μg/g of chlorine and 1 to 100 μg/g of fluorine in 1-g samples of nuclear-grade plutonium dioxide.

39.1 This test method coves the determination of sulfur in the concentration range from 10 to 600 μg/g for samples of nuclear-grade plutonium dioxide powders or pellets.

48.1 This test method covers the determination of dysprosium, europium, gadolinium, and samarium in plutonium dioxide (PuO₂) in concentrations of 0.1 to 10 μg/g of PuO₂.

FIG. 5 Schematic Diagram of Atmosphere Chamber

56.1 This test method covers the determination of 36 impurity elements in nuclear-grade plutonium dioxide (PuO₂). The concentration ranges covered by the method and the analytical lines used for each element are listed in Table 1.

TABLE 1 Impurity Elements, Lines, and Concentration Limits

ElementWavelength, ÅConcentration
Range, ppm Al2567.99^A10–500 Al3082.68^A Ag3280.681–250 As2349.8410–250 Au2427.952.5–50 B2497.731–50 Ba4554.032.5–100 (first order) Be2348.610.5–25 Bi3067.722.5–100 Ca3933.6710–1000 Cd2288.021–100 Co2407.2510–1000 Co3044.00 Cu3247.541–250 Cr2835.63^A5–500 Fe2983.57^A10–1000 Ga2450.07^A1–500 Ga2943.64 In3039.362.5–100 K7664.913–1000 (first order) Mg2802.701–1000 Mn2798.275–250 Mo^B3132.595–250 Ni3002.49^A10–1000 P2553.28100–1000 Pb2614.185–100 Pd3242.702.5–100 Sb2598.052.5–100 Si2514.32^A10–300 Sn2863.332.5–100 Sr4607.335–100 (first order) Ti3223.525–100 V^B3183.98^A5–100 W^B2724.35^A20–200 Zn3345.0210–250 Zr3438.235–100

^A These elements are determined with the aid of a microphotometer.

^B These elements are analyzed by using a AgCl carrier and PdCl₂ as an internal standard. Mix 20 mg of PdCl₂ with 10.0 g of AgCl. Add 80 mg of this mixture to 120 mg of PuO₂ sample-blend before loading 50-mg charges in a graphite electrode ASTM-Type-S-4 (follow 96.2.2).

71.1 This test method covers the determination of moisture in plutonium dioxide samples. Detection limits are as low as 10 μg.

79.1 This test method covers the measurement of volatiles other than water in reactor-grade plutonium dioxide pellets (16). The lower limit of the test method using the described equipment and a sample of approximately 1 g is 0.01 cm³ per gram of sample at STP conditions.

87.1 This test method covers the determination of rare earths in plutonium dioxide over the range from 10 to 200 μg/g.

97.1 This test method covers the determination of the isotopic composition of plutonium in nuclear-grade plutonium dioxide powders and pellets.

106.1 This test method is applicable to the determination of the oxygen-to-metal atom ratio (O/M) in plutonium dioxide pellets and powders.