ASTM C922-21

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it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: C922 − 14 C922 − 21
Standard Specification for
Sintered Gadolinium Oxide-Uranium Dioxide Pellets for
Light Water Reactors
This standard is issued under the fixed designation C922; 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.
INTRODUCTION
This specification is intended to provide the nuclear industry with a general specification for
gadolinium oxide-uranium dioxide pellets.(U,Gd)O pellets for light water reactor use. It recognizes
the diversity of manufacturing methods by which gadolinium(U,Gd)O oxide-uranium dioxide pellets
are produced and the many special requirements for chemical and physical characterization that may
be imposed by the operating conditions to which the pellets will be subjected in specific reactor
systems. different light water reactors. Therefore, it is anticipated that the purchaser may supplement
this specification with additional requirements for specific applications.
1. Scope
1.1 This specification is for finished sintered gadolinium(U,Gd)O oxide-uranium dioxide pellets for use in light-water reactors.
pellets. It applies to gadolinium(U,Gd)O oxide-uranium dioxide pellets containing uranium (U) of any U concentration and any
concentration of gadolinium oxide.oxide (Gd O ) for use in nuclear reactors.
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1.2 This specification recognizes the presence of reprocessed uraniumU in the fuel cycle and consequently defines isotopic limits
for gadolinium(U,Gd)O oxide-uranium dioxide pellets made from commercial grade UO . Such commercial grade UO is defined
2 2 2
so that, regarding fuel design and manufacture, the product is essentially equivalent to that made from unirradiated uranium.U.
UO falling outside these limits cannot necessarily be regarded as equivalent and may thus need special provisions at the fuel
fabrication plant or in the fuel design.
1.3 This specification does not include (1a) provisions for preventing criticality accidents or accidents, (2b) requirements for
health and safety. safety, (c) avoidance of hazards, or (d) shipping precautions and controls. Observance of this specification does
not relieve the user of the obligation to be aware of and conform to all applicable international, federal, state, and local regulations
pertaining to possessing, shipping, processing, or using source or special nuclear material. Examples of U.S. Governmental
documents are Code of Federal Regulations (Latest Edition), Title 10, Part 50, Title 10, Part 70, Title 10, Part 71, and Title 49,
Part 173.
1.4 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this
standard.
This specification is under the jurisdiction of ASTM Committee C26 on Nuclear Fuel Cycle and is the direct responsibility of Subcommittee C26.02 on Fuel and Fertile
Material Specifications.
Current edition approved Jan. 1, 2014Jan. 1, 2021. Published February 2014February 2021. Originally approved in 1983. Last previous edition approved in 20082014 as
C922 – 08.C922 – 14. DOI: 10.1520/C0922-14.10.1520/C0922-21.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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1.5 The following precautionary caveat pertains only to the technical requirements portion, Section 4, of this specification: 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 safety, health, and healthenvironmental practices and determine the applicability
of regulatory limitations prior to use.
1.6 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:
C753 Specification for Nuclear-Grade, Sinterable Uranium Dioxide Powder
C859 Terminology Relating to Nuclear Materials
C888 Specification for Nuclear-Grade Gadolinium Oxide (Gd O ) Powder
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C968 Test Methods for Analysis of Sintered Gadolinium Oxide-Uranium Dioxide Pellets
C996 Specification for Uranium Hexafluoride Enriched to Less Than 5 % U
E105 Practice for Probability Sampling of Materials
E112 Test Methods for Determining Average Grain Size
2.2 ANSI Standard:
ANSI/ASME NQA-1 Quality Assurance Requirements for Nuclear Facility Applications
2.3 U.S. Government Documents:
Code of Federal Regulations (Latest Edition), Regulations, Title 10, Part 50,50 Domestic Licensing of Production and
Utilization Facilities
Code of Federal Regulations Title 10, Part 70, Domestic Licensing of Special Nuclear Material
Code of Federal Regulations,Regulations Title 10, Part 71, Packaging and Transportation of Radioactive Material
Code of Federal Regulations,Regulations Title 49, Part 173, Shippers—General Requirements for Shipments and Packagings
Regulatory Guide 1.126, An Acceptable Model and Related Statistical Methods for the Analysis of Fuel Densification, current
version
2.4 NRC Guide
Regulatory Guide 1.126 An Acceptable Model and Related Statistical Methods for the Analysis of Fuel Densification, current
version
3. Terminology
3.1 Definitions—For definitions of terms, refer to Terminology C859.
3.1 Definitions:
3.1.1 For definitions of terms, refer to Terminology C859.
4. Technical Requirements
4.1 Major Constituents—Gadolinium(U,Gd)O oxide-uranium dioxide pellets shall be fabricated using major constituents that
meet the requirements of Specifications C753 and C888.
4.2 Chemical Requirements—All chemical analyses shall be performed on portions of the representative sample prepared in
accordance with Section 6. Analytical chemistry methods used shall be as stated in Test Methods C968 (latest edition) or
demonstrated equivalent as mutually agreed to between the seller and the buyer.
4.2.1 Impurity Content—The impurity content shall not exceed the individual element limit specified in Table 1 on a uraniumU
weight basis. The summation of the contribution of each of the impurity elements listed in Table 1 shall not exceed 1500 μg/g U.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume 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.gpo.gov/
fdsys/browse/collectionCfr.action?collectionCode-CFR. 20401-0001, http://www.access.gpo.gov.
Available from U.S. Nuclear Regulatory Commission, Washington, DC 20555. Attention: Director, Division of Document Control, U. S. Nuclear Regulatory Commission
(NRC), 11555 Rockville Pk., Rockville, MD 20852, http://www.nrc.gov.
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TABLE 1 Impurity Elements and Maximum Concentration Limits
Maximum
Element Concentration
Limit (μg/g U)
Aluminum 250
Carbon 100
Calcium200 + magnesium
Chlorine 25
Chromium 250
Fluorine 15
Hydrogen (total from all sources) 1.3
Iron 500
Nickel 250
Nitrogen 75
Silicon 500
Thorium 10
TABLE 1 Impurity Elements and Maximum Concentration Limits
Maximum
Element Concentration
Limit (μg/g U)
Aluminum (Al) 250
Carbon (C) 100
Calcium (Ca) + magnesium (Mg) 200
Chlorine (Cl) 25
Chromium (Cr) 250
Fluorine (F) 15
Hydrogen (H, total from all sources) 1.3
Iron (Fe) 500
Nickel (Ni) 250
Nitrogen (N) 75
Silicon (Si) 500
Thorium (Th) 10
If an element analysis is reported as “less than” a given concentration, this “less than” value shall be used in the determination
of total impurities. The thorium measurements required by Table 1 may be waived, provided that the seller can otherwise
demonstrate compliance with this specification, for instance, through the seller’s quality assurance records.
4.2.2 Stoichiometry—The oxygen-to-metal ratio of sintered fuel pellets shall be within the range from 1.98 to 2.02.
4.2.3 Moisture Content—The moisture content limit is included in the total hydrogen limit (see Table 1).
4.2.4 Gd O Concentration—The gadolinium oxide (GdGd O ) concentration shall be as specified in the purchase order.
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4.3 Nuclear Requirements:
4.3.1 Isotopic Content: Content—For (U,Gd)O pellets with an isotopic content of U between that of natural uranium and below
5 %, the isotopic limits of Specification C996 shall apply, unless otherwise agreed upon between the buyer and the seller. If the
U content is greater than enriched commercial grade UF requirements, the isotopic analysis requirements of Specification C996
shall apply. The specific isotopic measurements required by Specification C996 may be waived, provided that the seller can
otherwise demonstrate compliance with Specification C996, for instance, through the seller’s quality assurance records. A U
content greater than the one specified in Specification C996 for Commercial grade UF may be agreed upon between the buyer
and the seller.
4.3.2 For (U,Gd)O pellets not having an assay in the range set forth in 4.3.1, the isotopic requirements shall be as agreed upon
between the buyer and the seller.
4.4 Physical Characteristics:
4.4.1 Dimensions—The dimensions of the pellet and their tolerances shall be as specified by the buyer. These shall include
diameter, length, perpendicularity, and, as required, other geometric parameters including surface finish.agreed upon between the
buyer and seller, other parameters including end-face configuration and surface finish. The diameter can be determined by three
(3) multiple-point measurements at a minimum: middle and the two extremities of the pellet. Length measurements shall be made
between the furthest extremities of the pellet on the land area.
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4.4.2 Pellet Density—The density and tolerance of sintered pellets shall be as specified by the buyer. The theoretical density for
UO of natural isotopic content shall be considered to be 10.96 g/cm . The theoretical density for the (U,Gd)O shall be determined
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as agreed upon between the buyer and the seller.seller (see Note 1). Density measurements shall be made by th
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