ASTM D5411-93(2005)e1
(Practice)Standard Practice for Calculation of Average Energy Per Disintegration (E) for a Mixture of Radionuclides in Reactor Coolant
Standard Practice for Calculation of Average Energy Per Disintegration (E) for a Mixture of Radionuclides in Reactor Coolant
SCOPE
1.1 This practice applies to the calculation of the average energy per disintegration (E) for a mixture of radionuclides in reactor coolant water.
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, which are provided for information only and are not considered standard.
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.
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An American National Standard
e1
Designation: D 5411 – 93 (Reapproved 2005)
Standard Practice for
¯
Calculation of Average Energy Per Disintegration (E) for a
Mixture of Radionuclides in Reactor Coolant
This standard is issued under the fixed designation D 5411; 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 (e) indicates an editorial change since the last revision or reapproval.
e NOTE—Editorial changes were made throughout in January 2005.
¯
1. Scope known composition of the mixture. E is computed by calcu-
lating the total beta/gamma energy release rate, in MeV, and
1.1 This practice applies to the calculation of the average
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dividing it by the total disintegration rate. The resultant E has
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energy per disintegration (E) for a mixture of radionuclides in
units of MeV per disintegration.
reactor coolant water.
1.2 The values stated in inch-pound units are to be regarded
5. Significance and Use
as standard. The values given in parentheses are mathematical
5.1 This practice is useful for the determination of the
conversions to SI units, which are provided for information
average energy per disintegration of the isotopic mixture found
only and are not considered standard.
in the coolant of a nuclear reactor (1). The resultant value is
1.3 This standard does not purport to address all of the
periodically reported upon, by the operators of nuclear power
safety concerns, if any, associated with its use. It is the
plants, in order to ensure that the 2-h radiation dose, measured
responsibility of the user of this standard to establish appro-
at the plant boundary, will not exceed an appropriately small
priate safety and health practices and determine the applica-
fraction of the Code of Federal Regulations, Title 10, part 100
bility of regulatory limitations prior to use.
dose guidelines.
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2. Referenced Documents 5.2 In calculating E, all the energy dissipated by charged
particles and photons in each nuclear radioactive transforma-
2.1 ASTM Standards:
tion is included. This accounting includes the energy released
D 1066 Practice for Sampling Steam
in the form of beta particles and gamma rays as well as energy
D 1129 Terminology Relating to Water
released from extra-nuclear transitions in the form of X-rays,
D 3370 Practices for SamplingWater from Closed Conduits
Auger electrons, and conversion electrons. However, not all
D 3648 Practices for the Measurement of Radioactivity
radionuclides present in a sample are included in the calcula-
2.2 Code of Federal Regulations:
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3 tion of E.
10CFR100 Reactor Cite Criteria
5.3 Individual, nuclear reactor, technical specifications vary
3. Terminology and each nuclear operator must be aware of limitations
affecting their operation. Typically, radio-iodines, radionu-
3.1 Definitions—For definitions of terms used in this prac-
clides with half lives of less than 10 min (except those in
tice, refer to Terminology D 1129.
equilibrium with the parent), and those radionuclides, identi-
4. Summary of Practice
fied using gamma spectrometry, with less than a 95 % confi-
¯ dence level, are not typically included in the calculation.
4.1 The average energy per disintegration, E (pronounced E
However, the operator must account for at least 95 % of the
bar), for a mixture of radionuclides is calculated from the
remaining activity. There are individual bases for each exclu-
sion.
This practice is under the jurisdiction of ASTM Committee D19 on Water and
5.3.1 Radio-iodines are typically excluded from the calcu-
is the direct responsibility of Subcommittee D19.04 on Methods of Radiochemical
¯
lation of E because many commercial nuclear reactors are
Analysis.
required to operate under a more conservative restriction of 1
Current edition approved Jan. 1, 2005. Published January 2005. Originally
approved in 1993. Last previous edition approved in 1999 as D 5411 – 93 (1999).
microCurie (37 kBq) per gram dose equivalent I-131 in the
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
reactor coolant.
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.
3 4
AvailablefromStandardizationDocumentsOrderDesk,Bldg.4SectionD,700 The boldface numbers in parentheses refer to a list of references at the end of
Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS. this practice.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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D 5411 – 93 (2005)
5.3.2 Excluding radionuclides with half-lives less than 10 additional gamma isotopic analyses of the sample at approxi-
min, except those in equilibrium with the parent, has several mately 30 days after collection.
bases. 9.3 Perform sufficient isotopic analyses of the liquid, gas-
5.3.2.1 The first basis considers the nuclear characteristics eous, and suspended fractions of the sample to ensure that at
of a typical reactor coolant. The radionuclides in a typical least 95 % of the coolant activity due to nongamma emitting
reactor coolant have half-lives of less than 4 min or have isotopes has been quantified.
half-lives greater than 14 min.This natural separation provides 9.4 Tabulate the concentrations, uniformly measured in
a distinct window for choosing a 10 min half-life cutoff. µCi/cc(37kBq/cc)orµCi/g(37kBq/g),ofallapplicablegamma
5.3.2.2 The second consideration is the predictable time and nongamma emitting radioisotopes identified in the sample.
delay,approximately30min,whichoccursbetweentherelease Some examples of the radioisotopes or types of radioisotopes
of the radioactivity from the reactor coolant to its release to the found in a typical sample are the radioactive noble gases, pure
environmentandtransporttothesiteboundary.Inthistime,the beta emiter such as tritium, carbon-14, strontium-89 and 90,
short-lived radionuclides have undergone the decay associated and yttrium-90, beta/gamma emitters such as cobalt-60, elec-
with several half-lives and are no longer considered a signifi- tron capture isotopes such as iron-55, and reactor coolant
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cant contributor to E. suspended and particulate material (commonly referred to as
5.3.2.3 A final practical basis is the difficulty associated crud).
with identifying short-lived radionuclides in a sample that
requires some significant time, relative to 10 min, to collect,
10. Calculation
transport, and analyze.
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10.1 Calculate the average energy per disintegration, E,in
5.3.3 Radionuclides identified using less than a 95 % con-
MeV according to the following equation:
fidence level are not typically included in the calculation to
n
improve the accuracy of the calculation (2).
~A * E !
(
i i
n 5 1
¯
E 5 (1)
n
6. Interferences
A
( i
n 5 1
6.1 There are no true interferences to this practice. How-
¯
ever, errors may result in the calculation of E from incorrectly
where:
analyzing the sample mixture.
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E = average energy per disintegration, MeV/
disintegration,
7. Sampling
A = activity of the ith radionuclide uniformly measured,
i
7.1 If samples are collected for analysis in support of this
µCi/cc or µCi/g, and
practice they should be representative of the matrix, be of
E = isotopic energy emission for the ith radionuclide,
i
sufficient volume to ensure adequate analysis, and be collected
MeV/disintegration.
in accordance with Practices D 1066, D 3370, and D 3648.
10.2 The values for A are simply the measured activity
i
7.2 In addition to the requirements of 7.1, if samples of
levels, uniformly measured in µCi/cc (37 kBq/cc) or µCi/g (37
reactor coolant are required in support of this practice, they
kBq/g), for each appropriate radionuclide identified in the
should typically be collected only after a minimum of 2
sample (for example, Co-60, Sr-90, Xe-133, etc.).
effective full-power days and 20 days of power operation have
10.3 The values for E are constant for each radionuclide
i
elapsed since the reactor was subcritical for 48 h or longer.
and depend upon the decay scheme for that radioisotope. E is
i
Individual nuclear operator technical specifications vary and
calculated from the following equation:
should be reviewed to determine specific requirements.
E 5 E ~beta!1 E ~CE! 1 E ~A! 1 E ~gamma!1 E ~X! (2)
i i i i i i
8. Calibration and Standardization
where:
8.1 Any calibrations and standardizations required in sup-
E (beta) = the average, abundance weighted, beta en-
i
port of this practice should be in accordance with the appli-
ergy per disintegration, MeV/disintegration,
cable sections of Practice D 3648.
E (CE) = the average, abundance weighted, conversion
i
electron energy per disintegration, MeV/
9. Procedure
disintegration,
9.1 Conduct all analyses in support of this practice in
E (A) = the average, abundance weighted, Auger
i
accordance with the applicable sections of Practice D 3648.
electron energy per disintegration, MeV/
9.2 Perform sufficient gamma isotopic analyses of the liq-
disintegration,
uid, gaseous, and suspended fractions of the sample to ensure
E(gamma) = the average, abundance weighted, gamma
i
thatatleast95 %ofthecoolantactivityduetogammaemitting energy per disintegration, MeV/
isotopes has been quantified. Samples should be analyzed at
disintegration, and
E (X) = the average, abundance weighted, X-ray en-
approximately 2 h, 24 h, and 7 days following sample
i
collection. Multiple sample analy
...
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