ASTM D7727-11(2016)

Standard Practice for Calculation of Dose Equivalent Xenon (DEX) for Radioactive Xenon Fission Products in Reactor Coolant

SIGNIFICANCE AND USE
5.1 Each power reactor has a specific DEX value that is their technical requirement limit. These values may vary from about 200 to about 900 μCi/g based upon the height of their plant vent, the location of the site boundary, the calculated reactor coolant activity for a condition of 1 % fuel defects, and general atmospheric modeling that is ascribed to that particular plant site. Should the DEX measured activity exceed the technical requirement limit, the plant enters an LCO requiring action on plant operation by the operators.  
5.2 The determination of DEX is performed in a similar manner to that used in determining DEI, except that the calculation of DEX is based on the acute dose to the whole body and considers the noble gases 85mKr, 85Kr, 87Kr, 88Kr, 131mXe, 133mXe, 133Xe, 135mXe, 135Xe, and 138Xe which are significant in terms of contribution to whole body dose.  
5.3 It is important to note that only fission gases are included in this calculation, and only the ones noted in Table 1. For example 83mKr is not included even though its half-life is 1.86 hours. The reason for this is that this radionuclide cannot be easily determined by gamma spectrometry (low energy X-rays at 32 and 9 keV) and its dose consequence is vanishingly small compared to the other, more prevalent krypton radionuclides.  
5.4 Activity from 41Ar, 19F, 16N, and 11C, all of which predominantly will be in gaseous forms in the RCS, are not included in this calculation.  
5.5 If a specific noble-gas radionuclide is not detected, it should be assumed to be present at the minimum-detectable activity. The determination of DOSE-EQUIVALENT XE-133 shall be performed using effective dose-conversion factors for air submersion listed in Table III.1 of EPA Federal Guidance Report No. 12,3 or the average gamma-disintegration energies as provided in ICRP Publication 38 (“Radionuclide Transformations”) or similar source.
SCOPE
1.1 This practice applies to the calculation of the dose equivalent to 133Xe in the reactor coolant of nuclear power reactors resulting from the radioactivity of all noble gas fission products.  
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.  
1.3 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.

General Information

• Status: Historical
• Publication Date: 31-Oct-2016
• ICS: 27.120.10 - Reactor engineering
• Technical Committee: D19 - Water
• Drafting Committee: D19.04 - Methods of Radiochemical Analysis

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D7727 − 11 (Reapproved 2016)
Standard Practice for
Calculation of Dose Equivalent Xenon (DEX) for Radioactive
Xenon Fission Products in Reactor Coolant
This standard is issued under the fixed designation D7727; 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.
85m 85 87 88 131m
1. Scope activitiesofnoble-gasnuclides Kr, Kr, Kr, Kr, Xe,
133m 133 135m 135 138
Xe, Xe, Xe, Xe, and Xe actually present.
1.1 This practice applies to the calculation of the dose
equivalent to Xe in the reactor coolant of nuclear power
3.1.1.1 Discussion—This is the general definition of DEX.
reactors resulting from the radioactivity of all noble gas fission
Each utility may have adopted modifications to this definition
products.
through agreement with the U.S. Nuclear Regulatory Commis-
sion (U.S. NRC).The definition as approved for each utility by
1.2 The values stated in inch-pound units are to be regarded
the U.S. NRC is the one that should be applied to the
as standard. The values given in parentheses are mathematical
calculations in this practice.
conversions to SI units that are provided for information only
and are not considered standard.
4. Summary of Practice
1.3 This standard does not purport to address all of the
4.1 A sample of fresh reactor coolant is analyzed for noble
safety concerns, if any, associated with its use. It is the
gas activities using gamma ray spectrometry. The individual
responsibility of the user of this standard to establish appro-
activity of each detectable radioactive fission gas is divided by
priate safety, health, and environmental practices and deter-
a factor that normalizes its dose to that of Xe. This practice
mine the applicability of regulatory limitations prior to use.
is to replace the previous practice of calculating the reactor
1.4 This international standard was developed in accor-
coolant Ē calculation when allowed by the plant’s revised
dance with internationally recognized principles on standard-
technical specifications. The quantity DEX is acceptable from
ization established in the Decision on Principles for the
a radiological dose perspective since it will result in a limiting
Development of International Standards, Guides and Recom-
condition of operation (LCO) that more closely relates the
mendations issued by the World Trade Organization Technical
non-iodine RCS activity limits to the dose consequence analy-
Barriers to Trade (TBT) Committee.
ses which form their bases.
2. Referenced Documents
NOTE 1—It is incumbent on the licensee to ensure that the dose
conversion factors (DCFs) used in the determination of DEX are consis-
2.1 ASTM Standards:
tent with the DCFs used in the applicable dose consequence analysis used
D3648 Practices for the Measurement of Radioactivity
by the plant in their dose calculation manual for radioactive releases.
D7282 Practice for Set-up, Calibration, and Quality Control
of Instruments Used for Radioactivity Measurements
5. Significance and Use
5.1 Each power reactor has a specific DEX value that is
3. Terminology
their technical requirement limit. These values may vary from
3.1 Definitions:
about 200 to about 900 µCi/g based upon the height of their
3.1.1 dose-equivalent Xe-133 (DEX), n—shall be that Xe
plant vent, the location of the site boundary, the calculated
concentration(microcuriespergram)thatalonewouldproduce
reactor coolant activity for a condition of 1 % fuel defects, and
the same acute dose to the whole body as the combined
general atmospheric modeling that is ascribed to that particular
plant site. Should the DEX measured activity exceed the
technical requirement limit, the plant enters an LCO requiring
This practice is under the jurisdiction ofASTM Committee D19 on Water and
action on plant operation by the operators.
is the direct responsibility of Subcommittee D19.04 on Methods of Radiochemical
Analysis.
5.2 The determination of DEX is performed in a similar
Current edition approved Nov. 1, 2016. Published November 2016. Originally
ɛ1
manner to that used in determining DEI, except that the
approved in 2011. Last previous edition approved in 2011 as D7727 – 11 . DOI:
10.1520/D7727-11R16.
calculation of DEX is based on the acute dose to the whole
For referenced ASTM standards, visit the ASTM website, www.astm.org, or 85m 85 87 88
body and considers the noble gases Kr, Kr, Kr, Kr,
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
131m 133m 133 135m 135 138
Xe, Xe, Xe, Xe, Xe, and Xe which are
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. significant in terms of contribution to whole body dose.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7727 − 11 (2016)
5.3 It is important to note that only fission gases are 7.2 Containers used for containing the noble gases must
included in this calculation, and only the ones noted inTable 1. “gas-tight” to ensure insignificant losses of radionuclides
83m
For example Kr is not included even though its half-life is during sample counting.
1.86 hours. The reason for this is that this radionuclide cannot
7.3 Separation may be achieved by any form of reactor
be easily determined by gamma spectrometry (low energy
coolant degassing process (for example, gas expansion into an
X-rays at 32 and 9 keV) and its dose consequence is vanish-
evacuated container) as long as the sample line remains
ingly small compared to the other, more prevalent krypton
pressurized until degasification can occur.
radionuclides.
41 19 16 11
5.4 Activity from Ar, F, N, and C, all of which
8. Calibration and Standardization
predominantly will be in gaseous forms in the RCS, are not
8.1 Any calibrations and standardizations required in sup-
included in this calculation.
port of this practice should be in accordance with the appli-
5.5 If a specific noble-gas radionuclide is not detected, it
cable sections of Practices D3648 and D7282 and in accor-
should be assumed to be present at the minimum-detectable
dancewiththemanufacturers’specifi
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
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.
´1
Designation: D7727 − 11 D7727 − 11 (Reapproved 2016)
Standard Practice for
Calculation of Dose Equivalent Xenon (DEX) for Radioactive
Xenon Fission Products in Reactor Coolant
This standard is issued under the fixed designation D7727; 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.
ε NOTE—Editorial corrections made throughout in March 2014.
1. Scope
1.1 This practice applies to the calculation of the dose equivalent to Xe in the reactor coolant of nuclear power reactors
resulting from the radioactivity of all noble gas fission products.
1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only and are not considered standard.
1.3 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.
2. Referenced Documents
2.1 ASTM Standards:
D3648 Practices for the Measurement of Radioactivity
D7282 Practice for Set-up, Calibration, and Quality Control of Instruments Used for Radioactivity Measurements
3. Terminology
3.1 Definitions:
3.1.1 DOSE-EQUIVALENT XE-133 (DEX), n—shall be that Xe concentration (microcuries per gram) that alone would
85m 85 87 88 131m
produce the same acute dose to the whole body as the combined activities of noble-gas nuclides Kr, Kr, Kr, Kr, Xe,
133m 133 135m 135 138
Xe, Xe, Xe, Xe, and Xe actually present.
This practice is under the jurisdiction of ASTM Committee D19 on Water and is the direct responsibility of Subcommittee D19.04 on Methods of Radiochemical Analysis.
Current edition approved May 15, 2011Nov. 1, 2016. Published June 2011November 2016. Originally approved in 2011. Last previous edition approved in 2011 as
ɛ1
D7727 – 11 . DOI: 10.1520/D7727-11E01.10.1520/D7727-11R16.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
3.1.1.1 Discussion—
This is the general definition of DEX. Each utility may have adopted modifications to this definition through agreement with the
U.S. Nuclear Regulatory Commission (U.S. NRC). The definition as approved for each utility by the U.S. NRC is the one that
should be applied to the calculations in this practice.
4. Summary of Practice
4.1 A sample of fresh reactor coolant is analyzed for noble gas activities using gamma ray spectrometry. The individual activity
of each detectable radioactive fission gas is divided by a factor that normalizes its dose to that of Xe. This practice is to replace
the previous practice of calculating the reactor coolant Ē calculation when allowed by the plant’s revised technical specifications.
The quantity DEX is acceptable from a radiological dose perspective since it will result in a limiting condition of operation (LCO)
that more closely relates the non-iodine RCS activity limits to the dose consequence analyses which form their bases.
NOTE 1—It is incumbent on the licensee to ensure that the dose conversion factors (DCFs) used in the determination of DEX are consistent with the
DCFs used in the applicable dose consequence analysis used by the plant in their dose calculation manual for radioactive releases.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D7727 − 11 (2016)
5. Significance and Use
5.1 Each power reactor has a specific DEX value that is their technical requirement limit. These values may vary from about
200 to about 900 μCi/g based upon the height of their plant vent, the location of the site boundary, the calculated reactor coolant
activity for a condition of 1 % fuel defects, and general atmospheric modeling that is ascribed to that particular plant site. Should
the DEX measured activity exceed the technical requirement limit, the plant enters an LCO requiring action on plant operation by
the operators.
5.2 The determination of DEX is performed in a similar manner to that used in determining DEI, except that the calculation
85m 85 87 88 131m 133m 133
of DEX is based on the acute dose to the whole body and considers the noble gases Kr, Kr, Kr, Kr, Xe, Xe, Xe,
135m 135 138
Xe, Xe, and Xe which are significant in terms of contribution to whole body dose.
5.3 It is important to note that only fission gases are included in this calculation, and only the ones noted in Table 1. For example
83m
Kr is not included even though its half life half-life is 1.86 hours. The reason for this is that this radionuclide cannot be easily
determined by gamma spectrometry (low energy X-rays at 32 and 9 keV) and its dose consequence is vanishingly small compared
to the other, more prevalent krypton radionuclides.
41 19 16 11
5.4 Activity from Ar, F, N, and C, all of which predominantly will be in gaseous forms in the RCS, are not included in
this calculation.
5.5 If a specific noble-gas radionuclide is not detected, it should be assumed to be present at the minimum-detectable activity.
The determination of DOSE-EQUIVALENT XE-133 shall be performed using effective dose-conversion factors for air submersion
listed in Table III.1 of EPA Federal Guidance Report No. 12 12,(1), or the average gamma-disintegration energies as provided in
ICRP Publication 38 (“Radionuclide Transformations”) or similar source.
6. Interferences
6.1 The analytical determination of the radionuclides used for this calculation is made by gamma ray spectrometry.
Commercially available software is generally used to perform the spectrum analysis and data reduction. However, there can be
significant number of interferences from gamma ray emitters with multiple gamma ray emissions. The user must carefully select
the appropriate interference free interference-free gamma ray energy for each radionuclide in order to determine accurately the
activity of each radionuclide.
6.2 The short half-lives of several of the noble gas radionuclides, the low abundance of their gamma rays, and high background
activity at their principal gamma ray energies, may require that separation of the gases from the reactor coolant liquid be performed
in order to reliably determine t
...