ASTM C1853-17

Standard Test Method for The Determination of Carbon (Total) Content in Mixed Oxide ((U, Pu)O<inf>2</inf>) Sintered Pellets by Direct Combustion-Infrared Detection Method

SIGNIFICANCE AND USE
5.1 MOX is used as a nuclear-reactor fuel. This test method is designed to determine whether the carbon content of the pellets meet the requirements of the fuel specification. Examples of these requirements are given in Specification C833.  
5.2 This method is suitable for all sintered MOX pellets containing up to 12 weight % PuO2 when the UO2 and PuO2 meet the requirements of Specifications C753 and C757. The method uncertainty is related to the concentration of the carbon in the sample. At lower concentrations, the relative uncertainty increases. At carbon contents close to the typical carbon content specification limit (100 μg carbon/g U + Pu metal) the method uncertainty is on the order of 5 %, but exact method performance is difficult to determine due to the lack of matrix matched certified reference material.
SCOPE
1.1 This test method is an alternative to Test Method C698 for the determination of carbon in nuclear grade sintered mixed oxide (MOX) fuel pellets. The method for the determination of carbon presented in Test Method C698 consists of combusting carbon contained in MOX pellets with oxygen in a high-frequency induction furnace and detecting the resulting carbon dioxide using a thermal conductivity cell. The method for the determination of carbon presented in this test method consists of combusting carbon contained in MOX pellets with oxygen in a high-frequency induction furnace and subsequent detection of the resulting carbon dioxide (CO2) using a non-dispersive infrared detector (NDIR). Sulfur oxide is stripped from the carrier gas stream by a cellulose filter prior to the detection of CO2.  
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.3 This standard may involve hazardous material, operations, and equipment. 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 consult and establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.  
1.4 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.

General Information

• Status: Published
• Publication Date: 31-May-2017
• ICS: 27.120.30 - Fissile materials and nuclear fuel technology
• Technical Committee: C26 - Nuclear Fuel Cycle
• Drafting Committee: C26.05 - Methods of Test

Relations

• Refers: ASTM C859-24 - Standard Terminology Relating to Nuclear Materials
• Effective Date: 01-Jan-2024
• Refers: ASTM C698-16 - Standard Test Methods for Chemical, Mass Spectrometric, and Spectrochemical Analysis of Nuclear-Grade Mixed Oxides ((U, Pu)O<inf>2</inf>)
• Effective Date: 01-Jun-2016
• Refers: ASTM C757-16 - Standard Specification for Nuclear-Grade Plutonium Dioxide Powder for Light Water Reactors
• Effective Date: 01-Apr-2016
• Refers: ASTM C1408-16 - Standard Test Method for Carbon (Total) in Uranium Oxide Powders and Pellets By Direct Combustion-Infrared Detection Method
• Effective Date: 01-Mar-2016
• Refers: ASTM C753-16 - Standard Specification for Nuclear-Grade, Sinterable Uranium Dioxide Powder
• Effective Date: 01-Feb-2016
• Refers: ASTM C859-14a - Standard Terminology Relating to Nuclear Materials
• Effective Date: 15-Jun-2014
• Refers: ASTM C859-14 - Standard Terminology Relating to Nuclear Materials
• Effective Date: 15-Jan-2014
• Refers: ASTM C859-13a - Standard Terminology Relating to Nuclear Materials
• Effective Date: 01-Jun-2013
• Refers: ASTM C859-13 - Standard Terminology Relating to Nuclear Materials
• Effective Date: 01-May-2013
• Refers: ASTM C833-13 - Standard Specification for Sintered (Uranium-Plutonium) Dioxide Pellets
• Effective Date: 01-Jan-2013
• Refers: ASTM C1068-03(2011) - Standard Guide for Qualification of Measurement Methods by a Laboratory Within the Nuclear Industry
• Effective Date: 01-Jun-2011
• Refers: ASTM C859-10b - Standard Terminology Relating to Nuclear Materials
• Effective Date: 01-Nov-2010
• Refers: ASTM C859-10a - Standard Terminology Relating to Nuclear Materials
• Effective Date: 01-Aug-2010
• Refers: ASTM C698-10 - Standard Test Methods for Chemical, Mass Spectrometric, and Spectrochemical Analysis of Nuclear-Grade Mixed Oxides ((U, Pu)O₂)
• Effective Date: 01-Jun-2010
• Refers: ASTM C859-10 - Standard Terminology Relating to Nuclear Materials
• Effective Date: 01-Feb-2010

Overview

ASTM C1853-17: Standard Test Method for the Determination of Carbon (Total) Content in Mixed Oxide ((U, Pu)O₂) Sintered Pellets by Direct Combustion-Infrared Detection Method establishes a reliable procedure for measuring total carbon content in nuclear-grade mixed oxide (MOX) fuel pellets. MOX pellets, composed of uranium dioxide (UO₂) and plutonium dioxide (PuO₂), are a critical component in nuclear reactor fuel. This standard plays a vital role in quality control, helping to verify whether the carbon content in MOX pellets conforms to fuel specifications and industry requirements.

The standard employs a process that combusts carbon in MOX pellets using a high-frequency induction furnace, followed by detection of resulting carbon dioxide (CO₂) with a non-dispersive infrared detector (NDIR). The method provides a precise, alternative approach to other carbon determination standards, supporting the nuclear fuel industry’s commitment to safety and performance.

Key Topics

• Scope and Applicability:

  • Suitable for sintered MOX pellets containing up to 12 weight % PuO₂
  • Addresses materials compliant with relevant uranium and plutonium oxide specifications
  • Primarily intended for nuclear fuel pellet manufacturers and laboratories

• Test Methodology:

  • Direct combustion of sample with oxygen in an induction furnace
  • CO₂ produced is separated from other gases and impurities using filtration and chemical traps
  • Quantification through NDIR technology, ensuring specific and reliable carbon measurement

• Uncertainty and Limitations:

  • Measurement uncertainty increases at lower carbon concentrations
  • Method accuracy is influenced by the absence of MOX matrix-matched certified reference materials
  • Typically, uncertainty is around 5% near the specification limit

• Safety Considerations:

  • The procedure involves hazardous chemicals, radioactive materials, and high-temperature equipment
  • Strict safety protocols and regulatory compliance are essential for operators

Applications

• Quality Control for Nuclear Fuel Manufacturing:

  • Ensures MOX fuel pellets meet stringent carbon content specifications, essential for efficient reactor operation and fuel integrity

• Regulatory Compliance:

  • Supports adherence to national and international nuclear material standards through precise impurity analysis

• Laboratory Testing:

  • Provides analytical laboratories with a robust technique for evaluating carbon in MOX pellets
  • Useful in performance validation and certification processes for nuclear materials

• Research and Development:

  • Facilitates the development and optimization of advanced nuclear fuels by allowing accurate monitoring of impurity levels

Related Standards

• ASTM C698 – Alternative test methods for chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade mixed oxides
• ASTM C753 – Specification for nuclear-grade, sinterable uranium dioxide powder
• ASTM C757 – Specification for nuclear-grade plutonium dioxide powder for light water reactors
• ASTM C833 – Specification for sintered (uranium-plutonium) dioxide pellets for light water reactors
• ASTM C859 – Terminology relating to nuclear materials
• ASTM C1068 – Guide for qualification of measurement methods by laboratories in the nuclear industry
• ASTM C1408 – Test method for carbon (total) in uranium oxide powders and pellets by direct combustion-infrared detection method
• ISO 21614 – Nuclear fuel technology – Determination of carbon content by combustion and infrared absorption spectrometry

Practical Value

Adopting ASTM C1853-17 ensures reliable and verifiable determination of carbon content in MOX pellets, directly impacting the safety, efficiency, and regulatory acceptance of nuclear reactor fuels. Laboratories and fuel manufacturers implementing this standard benefit from enhanced measurement precision, streamlined quality assurance, and alignment with international best practices in nuclear fuel analysis.

Standards Content (Sample)

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.
Designation: C1853 − 17
Standard Test Method for
The Determination of Carbon (Total) Content in Mixed Oxide
((U, Pu)O ) Sintered Pellets by Direct Combustion-Infrared
Detection Method
This standard is issued under the fixed designation C1853; 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 2. Referenced Documents
2.1 ASTM Standards:
1.1 This test method is an alternative to Test Method C698
C698 Test Methods for Chemical, Mass Spectrometric, and
forthedeterminationofcarboninnucleargradesinteredmixed
Spectrochemical Analysis of Nuclear-Grade Mixed Ox-
oxide (MOX) fuel pellets.The method for the determination of
ides ((U, Pu)O )
carbon presented in Test Method C698 consists of combusting
C753 Specification for Nuclear-Grade, Sinterable Uranium
carbon contained in MOX pellets with oxygen in a high-
Dioxide Powder
frequency induction furnace and detecting the resulting carbon
C757 Specification for Nuclear-Grade Plutonium Dioxide
dioxide using a thermal conductivity cell. The method for the
Powder for Light Water Reactors
determination of carbon presented in this test method consists
C833 Specification for Sintered (Uranium-Plutonium) Diox-
of combusting carbon contained in MOX pellets with oxygen
inahigh-frequencyinductionfurnaceandsubsequentdetection ide Pellets for Light Water Reactors
C859 Terminology Relating to Nuclear Materials
of the resulting carbon dioxide (CO ) using a non-dispersive
infrared detector (NDIR). Sulfur oxide is stripped from the C1068 Guide for Qualification of Measurement Methods by
a Laboratory Within the Nuclear Industry
carrier gas stream by a cellulose filter prior to the detection of
CO . C1408 Test Method for Carbon (Total) in Uranium Oxide
Powders and Pellets By Direct Combustion-Infrared De-
1.2 The values stated in SI units are to be regarded as
tection Method
standard. No other units of measurement are included in this
2.2 ISO Standards:
standard.
ISO 21614 Nuclear Fuel Technology – Determination of
1.3 This standard may involve hazardous material,
Carbon Content of UO , (U,Gd)O and (U, Pu)O Pow-
2 2 2
operations, and equipment. This standard does not purport to
ders and Sintered Pellets – Combustion in a High-
address all of the safety concerns, if any, associated with its
Frequency Induction Furnace – InfraredAbsorption Spec-
use. It is the responsibility of the user of this standard to
trometry
consult and establish appropriate safety and health practices
3. Terminology
and determine the applicability of regulatory limitations prior
to use.
3.1 For definitions of terms used in this test method but not
1.4 This international standard was developed in accor-
defined herein, refer to terminology relating to nuclear mate-
dance with internationally recognized principles on standard-
rials in Terminology C859.
ization established in the Decision on Principles for the
3.2 Definitions of Terms Specific to This Standard:
Development of International Standards, Guides and Recom-
3.2.1 MOX—nuclearfuelcomposedofamixtureofuranium
mendations issued by the World Trade Organization Technical
and plutonium oxides ((U, Pu)O ).
Barriers to Trade (TBT) Committee.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
This test method is under the jurisdiction ofASTM Committee C26 on Nuclear Standards volume information, refer to the standard’s Document Summary page on
Fuel Cycle and is the direct responsibility of Subcommittee C26.05 on Methods of the ASTM website.
Test. Available from International Organization for Standardization (ISO), ISO
Current edition approved June 1, 2017. Published June 2017. DOI: 10.1520/ Central Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier,
C1853-17. Geneva, Switzerland, http://www.iso.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1853 − 17
3.2.2 sintering—the process of forming a solid mass of increases. At carbon contents close to the typical carbon
material by heat or pressure, or both, without melting it to the content specification limit (100 µg carbon/gU+Pu metal) the
point of liquefaction. method uncertainty is on the order of 5 %, but exact method
performance is difficult to determine due to the lack of matrix
3.2.3 reference material—non-matrix matched material
matched certified reference material.
traceabletoareferencematerialfromanationalstandardsbody
such as the U.S. National Institute for Standards and Technol-
6. Interferences
ogy (NIST) or equivalent; matrix matched reference materials
6.1 The carbon detectors in the gas analyzer system are
for MOX pellets are not available.
selective.The wavelength of detection is chosen to specifically
3.3 Acronyms:
detect only carbon dioxide. Furthermore, after the sample
3.3.1 NDIR—Non Dispersive Infrared Detector.
combustion the carrier gas containing the carbon dioxide and
3.3.2 THC—Total Hydrocarbon
otherpotentiallyinterferingimpurities(sulfur,water,andsmall
particulate matter) pass through a series of filters and purifying
4. Summary of Test Method
reagents that remove these impurities from the carrier gas
4.1 The method consists of crushing a MOX pellet, weigh-
stream leaving only CO in the stream at the detector. If the
ing an approximately 1 g fragment of the pellet into a crucible
MOX pellets are made from UO and PuO that meet the
2 2
with an accelerator and combustion of the carbon contained in
requirements of Specification C753 and C757, all interferences
the sample under a stream of high pressure oxygen in a
are eliminated by the purification system.
high-frequency induction furnace followed by detection of the
6.2 The crucibles and accelerator chemicals, if they contain
carbon dioxide by a non-dispersive infrared (NDIR) cell.
carbon, will yield erroneously high results for the sample. The
During combustion of the sample, the carbon and sulfur
analytical method requires the use of pre-ignited crucibles and
components are oxidized to release carbon monoxide (CO),
running blanks with accelerator chemical in pre-ignited cru-
carbon dioxide (CO ) and sulfur dioxide (SO ). These sample
2 2
cible to reduce and correct for the blanks in the results for
impurities are swept by the oxygen (O ) carrier gas through a
samples.
series of filters to remove dust and water and then the gases
6.3 The O carrier gas could contain water, hydrocarbons
flow through an oxidation furnace (PtSiO ).All CO is oxidized
and CO and is filtered prior to injection in the sample
to CO and SO is oxidized to SO . The SO is trapped in a
2 2 3 3
combustion chamber to remove these potentially interfering
cellulose column and the CO and carrier gas stream flow
components.
through a selective NDIR detector. Analyzers are often
equipped with two NDIR cells, one for the detection of carbon
6.4 Weighing accuracy of the samples is critical to the
andoneforsulfur,butthispracticedescribesonlythedetection
method. If the balance meets the specification in 7.1,is
of carbon.The simultaneous detection of carbon and sulfur can
calibrated in accordance with manufacturer’s guidance, and is
however be performed without impact to the performance of
checked by procedure, the potential for the balance to be a
this test method, but in this case the cellulose column is not
source of error is insignificant.
used.
6.5 High levels of halides can damage the NDIR detector
4.2 The detector signal plotted against time is a function of
cells.Halidesarenottypicallypresentinhighconcentrationsin
the concentration of the CO in the carrier gas. The area below
2 sintered MOX fuel pellets and therefore no specific filter is
the curve (integral) corresponds to the total amount of carbon
necessary for removal of halides.
in the sample. The peak is integrated by the software and the
concentration is calculated taking into account the calibration
7. Apparatus
factor, the blank analysis, and the sample weight. The calibra-
7.1 Analytical Balance, with precision 60.1 mg.
tion of the analyzer is made by means of a reference material.
7.2 Crucibles, expendable alumina or similar refractory
Blank values are obtained from analyzing the pre-ignited
material. The crucible must be pre-ignited at a temperature of
crucibleswithnosampleandanaccelerator,whichisaddedfor
900°C or higher for a time sufficient to produce constant blank
optimum combustion. The blank results are stored. The final
values.
sample result is corrected by the blank value and the results are
expressed in µg carbon/g MOX.
7.3 Muffle Furnace or Tube Furnace, capable of attaining
temperature of 900°C, for pre-igniting crucibles.
5. Significance and Use
7.4 Desiccator, used to store the pre-ignited crucibles.
5.1 MOX is used as a nuclear-reactor fuel. This test method
7.5 Pellet Crusher, used to fragment the pellets.
is designed to determine whether the carbon content of the
pellets meet the requirements of the fuel specification. Ex- 7.6 Carbon Analyzer, consisting of an induction-heated
amples of these requirements are given in Specification C833. furnace suitable for operation at 1600 to 1700°C, an NDIR for
measuring carbon dioxide, and auxiliary purification systems.
5.2 This method is suitable for all sintered MOX pellets
7.6.1 Typical detector range (8 µg carbon/gU+Pu metal –
containing up to 12 weight % PuO when the UO and PuO
2 2 2
1000 µg carbon/gU+Pu metal).
meet the requirements of Specifications C753 and C757. The
methoduncertaintyisrelatedtotheconcentrationofthecarbon 7.7 Aluminum Foil, used to wrap the ceramic crucibles after
in the sample.At lower concentrations, the relative uncertainty pre-ignition to decrease impurity reabsorption.
C1853 − 17
7.8 Tongs and Forceps, for handling crucibles and lids. appropriate filters to contain any small particle of plutonium.A
detailed discussion of the necessary precautions is beyond the
7.9 Stainless Steel Scoops and Spatulas, for handling pellet
scope of this test method. Personnel involved in these analyses
fragments, accelerator, and reference materials.
should be familiar with safe handling practices.
8. Reagents and Materials
10.2 The furnace, sample tube, and sample crucibles are
heated to >1600°C. Extreme care must be exercised to avoid
8.1 Purity of Reagents—Reagent grade chemicals shall be
burns or injury by quartz in a glove box and to avoid breaching
used in all tests. Unless otherwise indicated, it is intended that
the primary confinement boundary. Care should be taken to
all reagents shall conform to the specifications of the Commit-
avoid contacting gloves with hot surfaces. Typically these hot
tee onAnalytical Reagents of theAmerican Chemical Society,
surfaces are guarded and inaccessible during the heating
where such specifications are available. Other grades may be
process and therefore do not pose a risk to the operator.
used, provided it is first ascertained that the reagent is of
sufficiently high purity to permit its use without lessening the
10.3 Exercise appropriate caution when working with com-
accuracy of the determination.
pressed gases.
8.2 Sodium Hydroxide (NaOH) on a Fibrous Support—
10.4 This procedure uses hazardous chemicals. Use appro-
Captures CO .
priate precautions for handling corrosives, oxidizers, and
gases.
8.3 Magnesium Perchlorate (Mg(ClO ) —Removes H O.
4 2 2
8.4 Platinized Silica (PtSiO )—Oxidizes any generated CO
11. Preparation and Verification of Apparatus Prior to
and SO to CO and SO .
2 2 3
Sample Analysis
8.5 Cellulose Trap Packing (Surgical Grade Cotton or
11.1 Turn on the analyzer and set the operating controls of
Equivalent)—Traps SO .
the instrument system according to the operating instructions
8.6 Quartz Wool—For dust traps and to plug the reagent
for the specific equipment used.
tubes.
11.2 Verification of the Gases—Carrier gas flow and system
8.7 Accelerators—Use to achieve complete combustion of
pressurearetwoessentialparametersthatmustbecontrolledto
the samples. Copper metal, tungsten, tin-tungsten mixture,
ensure satisfactory performance of the instrument. Most ana-
copper oxide, granular tin, and high purity iron chip accelera-
lyzers are equipped with pressure regulation and electronic
tors for increased combustion temperature. These materials are
flow control.
available in appropriate purity and form from carbon analyzer
11.2.1 Ensure that the regulator valve is set to the correct
vendors. The criterion for satisfactory results is the absence of
valuefortheoxygenlinepermanufacturers’recommendations.
significant additional carbon release upon recombustion of the
11.2.2 The following gas pressure parameters should be
specimen.
checked during the analysis and are often automatically moni-
8.8 Silica Gel—Desiccant for the desiccator.
tored by the gas analyzer software: gas pressure when the
furnace is opening, gas pressure during leak test and gas flow
8.9 Oxygen Carrier Gas—≥99.999 % purity with inlet pres-
during analysis.
sure 350 to 500 kPa (g) or as specified by the manufacturer.
11.3 Verification of the Reagents—Change instrument col-
9. Reference Materials
umn packing and reagents as recommended by manufacturer.
9.1 The calibration of the analyzer is made by measuring
11.3.1 The sodium hydroxide changes color from dark to
materials with carbon content in the range of concentration light gray due to the reaction with CO . It should be replaced
expected in the MOX pellet traceable to a reference material when approximately half of the reagent tube has turned to a
from a national standards body such as the U.S. National
light gray color.
Ins
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