ASTM C784-20

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Designation: C784 − 16 C784 − 20
Standard Specification for
Nuclear-Grade Aluminum Oxide-Boron Carbide Composite
Pellets
This standard is issued under the fixed designation C784; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This specification applies to pellets composed of mixtures of aluminum oxide and boron carbide that may be ultimately used
in a reactor core, for example, in neutron absorber rods.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.after
SI units are provided for information only and are not considered standard.
1.3 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
C559 Test Method for Bulk Density by Physical Measurements of Manufactured Carbon and Graphite Articles
C750 Specification for Nuclear-Grade Boron Carbide Powder
C809 Test Methods for Chemical, Mass Spectrometric, and Spectrochemical Analysis of Nuclear-Grade Aluminum Oxide and
AluminumOxide-Boron Carbide Composite Pellets
C859 Terminology Relating to Nuclear Materials
C1031 Specification for Nuclear-Grade Aluminum Oxide Powder
E11 Specification for Woven Wire Test Sieve Cloth and Test Sieves
E105 Practice for Probability Sampling of Materials
2.2 ANSI Standard:
ANSI/ASME NQA-1 Quality Assurance Program Requirements for Nuclear Facilities
2.3 Government Standard:
Title 10,10 CFR 50 Title 10, Code of Federal Regulations, Energy Part 50 (10CFR50), Domestic 50—Domestic Licensing of
Production and Utilization Facilities
3. Terminology
3.1 Definitions:
3.1.1 Terms shall be defined in accordance with Terminology C859 except for the following:
3.1 Definitions of Terms Specific to This Standard:Definitions:
3.1.1 Terms shall be defined in accordance with Terminology C859, except for the following:
3.1.2 buyer—organization issuing the purchase order.
3.1.3 pellet—a fabricated geometric shape of aluminum oxide-boron carbide having a chemical composition as described in
Section 4.
This specification is under the jurisdiction of ASTM Committee C26 on Nuclear Fuel Cycle and is the direct responsibility of Subcommittee C26.03 on Neutron Absorber
Materials Specifications.
Current edition approved April 1, 2016Jan. 1, 2020. Published April 2016February 2020. Originally approved in 1976. Last previous edition approved in 20122016 as
C784 – 05 (2012).C784 – 16. DOI: 10.1520/C0784-16.10.1520/C0784-20.
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C784 − 20
3.1.4 pellet lot—that quantity of pellets produced from one powder mixture lot using one set of mixing and process parameters.
Pelletparameters; pellet lot size shall be agreed upon between the seller and the buyer.
3.1.5 powder mixture lot—a specified quantity of aluminum oxide and boron carbide made up of powders from one or more
sources blended together such that samples taken in accordance with Section 7 can be considered as representative of the entire
specified quantity.
3.1.6 seller—pellet supplier.
4. Technical Requirements
4.1 Major Constituents—Aluminum oxide-boron carbide pellets shall be fabricated using major constituents that meet the
requirements of Specifications C750 and C1031.
4.2 Chemical Composition:
4.2.1 Use analytical chemistry methods in accordance with Test Methods C809 or demonstrated alternate methods agreed upon
between the buyer and the seller.
4.2.2 The finished pellets shall conform to the following chemical analysis:
C784 − 20
Element Weight %, max
Silicon (Si) 2.0
Iron + Chromium + Nickel 0.6
(Fe + Cr + Ni)
Magnesium (Mg) 1.0
Sodium (Na) 0.2
Calcium (Ca) 0.3
Hafnium (Hf) 200 μg/g pellet
Fluorine (F) 50 μg/g pellet
Fluorine + Chlorine + Iodine + Bromine 100 μg/g pellet
(F + Cl + I + Br)
Gadolinium (Gd) 25 μg/g pellet
Samarium (Sm) 50 μg/g pellet
Europium (Eu) 50 μg/g pellet
Dysprosium (Dy) 50 μg/g pellet
Element Weight %, max
Silicon (Si) 2.0
Iron + Chromium + Nickel 0.6
(Fe + Cr + Ni)
Magnesium (Mg) 1.0
Sodium (Na) 0.2
Calcium (Ca) 0.3
Hafnium (Hf) 200 μg/g pellet
Fluorine (F) 50 μg/g pellet
Fluorine + Chlorine + Iodine + Bromine 100 μg/g pellet
(F + Cl + I + Br)
Gadolinium (Gd) 25 μg/g pellet
Samarium (Sm) 50 μg/g pellet
Europium (Eu) 50 μg/g pellet
Dysprosium (Dy) 50 μg/g pellet
Any elemental impurity not listed in 4.2.2 shall not exceed 1 weight % 1 weight % as determined by emission spectroscopy or
method agreed upon between buyer and seller. The sum of all impurities shall not exceed 4.0 weight %. A water-soluble boron limit
may be required in certain designs in which case it shall be determined on a sample crushed to pass through a No. 100 mesh
(150-μm) U.S. standard sieve (see Specification E11.)
4.2.3 Should elements not listed in 4.2.2 be of concern, their inclusion in the listing shall be mutually agreed upon between the
buyer and the seller.
4.2.4 In specifying the allowable range in B concentration the buyer shall consider the following:
4.2.4.1 Variations in chemical composition,
4.2.4.2 Bulk pellet density,
4.2.4.3 Boron isotopic composition,
4.2.4.4 Pellet dimensions, and
10 10
4.2.4.5 Typical units are grams of B per unit volume or grams of B per centimeterunit length.
4.2.5 The hydrogen impurity (including moisture content), the detailed procedure for measuring hydrogen, and packaging
requirements associated with hydrogen contamination
...