ASTM C1076-09(2015)

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Designation: C1076 − 09 C1076 − 09 (Reapproved 2015)
Standard Specification for
Nuclear Grade Hafnium Oxide Pellets
This standard is issued under the fixed designation C1076; 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 of stabilized cubic hafnium oxide used in nuclear reactors.
1.2 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.
2. Referenced Documents
2.1 ASTM Standards:
C559 Test Method for Bulk Density by Physical Measurements of Manufactured Carbon and Graphite Articles
C859 Terminology Relating to Nuclear Materials
C1098 Specification for Nuclear-Grade Hafnium Oxide Powder
E105 Practice for Probability Sampling of Materials
2.2 ANSI Standard:
ANSI/ASME NQA-1 Quality Assurance Requirements for Nuclear Facility Applications
2.3 U.S. Government Document:
Code of Federal Regulations, Title 10, Part 50—Energy (10CFR 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:
3.1.2 buyer—organization issuing the purchase order.
3.1.3 pellet—fabricated geometric shape of stabilized cubic hafnium oxide having a chemical composition as described in
Section 4.
3.1.4 pellet lot—the pellets produced from one hafnium oxide powder lot using one set of process parameters. Pellet lot size
shall be agreed upon between the seller and the buyer.
3.1.5 phase transformation—rearrangement of the atomic ordering of a crystalline lattice as a material is cycled through a
critical transformation or inversion temperature. The change from one crystalline phase to another may be accompanied by a
5,6
volume change that could lead to cracks or defects in articles fabricated from such materials.
3.1.6 powder lot—a specified quantity of hafnium oxide powder with stabilizing additive, blended together such that samples
taken in accordance with Section 7 can be considered as representative of the entire quantity.
3.1.7 seller—hafnium oxide pellet supplier.
3.1.8 stabilizing additive—a material which, when present in sufficient concentration in the subject material exhibiting the phase
transformation, produces a stabilized crystalline phase that does not undergo a transformation or inversion at any temperature
within the expected fabrication or usage regime of the manufactured pellet. The potentially deleterious volume change is therefore
avoided.
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 July 1, 2009Jan. 1, 2015. Published August 2009January 2015. Originally approved in 1987. Last previous edition approved in 20042009 as
C1076 – 97 (2004).C1076 – 09. DOI: 10.1520/C1076-09.10.1520/C1076-09R15.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Sevice at service@astm.org. For Annual Book of ASTM
Standardsvolume information, refer to the standard’s Document Summary page on the ASTM website.
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
Available from U.S. Government Printing Office Superintendent of Documents, 732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401, http://
www.access.gpo.gov.
Curtis, C. E., Doney, L. M., and Johnson, J. R., “Some Properties of Hafnium-Oxide, Hafnium-Silicate, Calcium-Hafnate, and Hafnium-Carbide,” Journal of American
Ceramics Society, Vol 37, 1954, pp. 458–465.
Brown, L. M., and Madiyasni, K. S., “Characterization of Alkoxy-Derived Yttria-Stabilized Hafnia,” Journal of American Ceramics Society, Vol 53, 1970, pp. 590–594.
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C1076 − 09 (2015)
4. Chemical Composition
4.1 The starting hafnium oxide powder shall be in accordance with Specification C1098.
4.2 A stabilizing additive shall be utilized with the hafnium oxide. The recommended stabilizing additive is yttrium oxide
(Y O ). The typical concentration range is 7 to 10 weight % Y O in the finished product. References to other stabilizing additives
2 3 2 3
(such as calcium oxide (CaO) and magnesium oxide (MgO)) may be found in the literature and these additives may be used if
agreed upon by the buyer and seller. It is cautioned, however, that the buyer should be aware of potential destabilization during
thermal cycling when MgO or CaO is used.
4.3 Use analytical chemistry methods as agreed upon between the buyer and the seller.
4.4 The hafnium concentration, in grams of hafnium per unit volume or grams of hafnium per unit length, may be specified by
the buyer. In specifying the allowable range in hafnium concentration, the buyer should consider the following:
4.4.1 Variations in chemical composition,
4.4.2 Pellet bulk density,
4.4.3 Type and concentration of stabilizing additive, and
4.4.4 Pellet dimensions and dimensional tolerances.
4.5 The impurity concentration, excluding zirconia and the stabilizing additive, shall not exceed 0.5 weight %. Individual
element limits are specified in Table 1. The buyer may specify additional limits for any elements not listed in Table 1.
4.6 The zirconium concentration shall not exceed 4.5 weight % on the basis of Zr/(Zr + Hf).
4.7 The moisture concentration limit is included in the total hydrogen limit (see Table 1).
5. Physical Requirements
5.1 Physical Dimensions:
5.1.1 Dimensional requirements shall be in accordance with applicable drawings and purchase order documents.
5.1.2 Pellet dimensions shall be measured to ensure compliance with the buyer’s requirements. Sampling plans to meet the
acceptance criteria shall be agreed upon between the buyer and the seller to ensure that the pellets represented by the sample are
within the required tolerance.
5.2 Density:
5.2.1 Pellet density limits shall be specified by the buyer. The incorporation of a stabilizing additive will introduce a change in
the theoretical density of the fabricated pellets and should be taken into account. The method of establishing the theoretical density
value shall be mutually agree
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