ASTM E704-19

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Designation: E704 − 13 E704 − 19
Standard Test Method for
Measuring Reaction Rates by Radioactivation of Uranium-
This standard is issued under the fixed designation E704; 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 test method covers procedures for measuring reaction rates by assaying a fission product (F.P.) from the fission
reaction U(n,f)F.P.
1.2 The reaction is useful for measuring neutrons with energies from approximately 1.5 to 7 MeV and for irradiation times up
to 30 to 40 years.years, provided that the analysis methods described in Practice E261 are followed.
1.3 Equivalent fission neutron fluence rates as defined in Practice E261 can be determined.
1.4 Detailed procedures for other fast-neutron detectors are referenced in Practice E261.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 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.
1.7 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:
E170 Terminology Relating to Radiation Measurements and Dosimetry
E181 Test Methods for Detector Calibration and Analysis of Radionuclides
E261 Practice for Determining Neutron Fluence, Fluence Rate, and Spectra by Radioactivation Techniques
E262 Test Method for Determining Thermal Neutron Reaction Rates and Thermal Neutron Fluence Rates by Radioactivation
Techniques
E320 Test Method for Cesium-137 in Nuclear Fuel Solutions by Radiochemical Analysis (Withdrawn 1993)
E393 Test Method for Measuring Reaction Rates by Analysis of Barium-140 From Fission Dosimeters
E705 Test Method for Measuring Reaction Rates by Radioactivation of Neptunium-237
E844 Guide for Sensor Set Design and Irradiation for Reactor Surveillance
E944 Guide for Application of Neutron Spectrum Adjustment Methods in Reactor Surveillance
E1005 Test Method for Application and Analysis of Radiometric Monitors for Reactor Vessel Surveillance
E1018 Guide for Application of ASTM Evaluated Cross Section Data File
3. Terminology
3.1 Definitions:
3.1.1 Refer to Terminology E170.
This test method is under the jurisdiction of ASTM Committee E10 on Nuclear Technology and Applicationsand is the direct responsibility of Subcommittee E10.05 on
Nuclear Radiation Metrology.
Current edition approved June 1, 2013Oct. 1, 2019. Published July 2013October 2019. Originally approved in 1984. Last previous edition approved in 20082013 as
E704 – 08.E704 – 13. DOI: 10.1520/E0704-13.10.1520/E0704-19.
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.
The last approved version of this historical standard is referenced on www.astm.org.
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E704 − 19
4. Summary of Test Method
238 235
4.1 High-purity U (<40 ppm U) is irradiated in a fast-neutron field, thereby producing radioactive fission products from
the reaction U(n,f)F.P.
137 137m 140 140 95 144
4.2 Various fission products such as Cs- Ba, Ba- La, Zr, and Ce can be assayed depending on the length of
irradiation, purpose of the experiment, etc.
4.3 The gamma rays emitted through radioactive decay are counted, and the reaction rate, as defined in Practice E261, is
calculated from the decay rate and the irradiation conditions.
4.4 The neutron fluence rate for neutrons with energies from approximately 1.5 to 7 MeV can then be calculated from the
spectral-weighted neutron activation cross section as defined in Practice E261.
237 238
4.5 A parallel procedure that uses Np instead of U is given in Test Method E705.
5. Significance and Use
5.1 Refer to Practice E261 for a general discussion of the determination of fast-neutron fluence rate with fission detectors.
5.2 U is available as metal foil, wire, or oxide powder (see Guide E844). It is usually encapsulated in a suitable container
to prevent loss of, and contamination by, the U and its fission products.
5.3 One or more fission products can be assayed. Pertinent data for relevant fission products are given in Table 1 and Table 2.
137 137m 134 136
5.3.1 Cs- Ba is chosen frequently for long irradiations. Radioactive products Cs and Cs may be present, which can
137 137m
interfere with the counting of the 0.662 MeV Cs- Ba gamma rays (see Test MethodsMethod E320).
140 140
5.3.2 Ba- La is chosen frequently for short irradiations (see Test Method E393).
95 95
5.3.3 Zr can be counted directly, following chemical separation, or with its daughter Nb using a high-resolution gamma
detector system.
TABLE 1 Recommended Nuclear Parameters for Certain Fission
Products
Maximum
γ Probability
Parent Primary
Fission Useful
of
A A
Half-Life Radiation
A
Product Irradiation
Decay
(1) (2) (keV)
(2)
Duration
Zr 64.032 (6) d 724.192 (4) 0.4427 (22) 6 months
756.725 (12) 0.5438
Mo 65.94 (1) h 739.500 (17) 0.1213 (22) 300 hours
777.921 (20) 0.0426 (8)
Ru 39.26 (2) d 497.085 (10) 0.910 (12) 4 months
137 B B
Cs 30.05 (8) yr 661.657 (3) 0.8499 (20) 30–40 years
140 140
Ba − La 12.7527 (23) d 537.261 (4) 0.2439 (22) 1–1.5 months
C
1596.21 (4) 0.9540 (8)
D
1.1515
Ce 284.91 (5) d 133.515 (2) 0.1109 (19) 2–3 years
TABLE 1 Recommended Nuclear Parameters for Certain Fission
Products
Maximum
γ Probability
Parent Primary
Fission of Useful
A A
Half-Life Radiation
A
Product Irradiation
Decay
(1,2,3) (2,3) (keV)
(4,2,3)
Duration
Zr 64.032 (6) d 724.193 (3) 0.4427 (22) 6 months
756.729 (12) 0.5438 (22)
Mo 2.7479 (6) d 739.500 (17) 0.1212 (15) 300 hours
777.921 (20) 0.0428 (8)
Ru 39.247 (13) d 497.085 (10) 0.910 (12) 4 months
137 B B
Cs 30.05 (8) yr 661.657 (3) 0.8499 (20) 30 – 40 years
140 140 C C
Ba − La 12.753 (4) d 537.303 (6) 0.2439 (22) 1–1.5 months
D
1596.203 (13) 0.9540 (5)
140 140 E
La/ Ba 1.1516 (5)
Ce 284.89 (6) d 133.5152 (20) 0.1083 (12) 2–3 years
A
The lightface numbers in parentheses are the magnitude of plus or minus
uncertainties in the last digit(s) listed.
B 137m
With Ba (2.552 min) in equilibrium.
C
The recommended half-life and gamma emission probabilities have been taken
from the Reference (3) data that was recommended at the time that the
recommended fission yields were set.
D 140
Probability of daughter La decay.
E 140 140
With This is the activity ratio of LaLa/ (1.67855 d) in transient equilibri-
um.Ba after reached transient equilibrium (t $ 19 days).
E704 − 19
TABLE 2 Recommended Fission Yields for Certain Fission
A
Products
A,B
Fissile Neutron Reaction Type JEFF-3.1.1
Fission Yield %
Isotope Energy Product Yield
238 95
U(n,f) 0.5 MeV Zr RC 5.19 ± 1.714 %
Mo RC 6.18 ± 1.6 %
Ru RC 6.03 ± 1.6 %
Cs RC 6.02 ± 2.52 %
137m
Ba RI 1.0169e-2 ± 36.5 %
Ba RC 5.68 ± 2.67 %
La RI 6.8165e-6 ± 64 %
Ce RC 4.67 ± 2.46 %
A
The JEFF-3.1/3.1.1 radioactive decay data and fission yields sub-libraries, JEFF
Report 20, OECD 2009, Nuclear Energy Agency.Agency (5).
B
All yield data given as a %; RC represents a cumulative yield; RI represents an
independent yield.
5.3.4 Ce is a high-yield fission product applicable to 2- to 3-year irradiations.
5.4 It is necessary to surround the U monitor with a thermal neutron absorber to minimize fission product production from
235 238 239 238 239
a quantity of U in the U target and from Pu from (n,γ) reactions in the U material. Assay of the Pu concentration
when a significant contribution is expected.
5.4.1 Fission product production in a light-water reactor by neutron activation product Pu has been calculated to be
insignificant (<2 %), compared to that from U(n,f), for an irradiation period of 12 years at a fast-neutron (E > 1 MeV) fluence
11 −2 −1 238
rate of 1 × 10 cm · s provided the U is shielded from thermal neutrons (see Fig. 2 of Guide E844).
5.4.2 Fission product production from photonuclear reactions, that is, (γ,f) reactions, while negligible near-power and
research-reactor cores, can be large for deep-water penetrations (36).
238 54 54
5.5 Good agreement between neutron fluence measured by U fission and the Fe(n,p) Mn reaction has been demonstrated
(47). The reaction U(n,f) F.P. is useful since it is responsive to a broader range of neutron energies than most threshold detectors.
5.6 The U fission neutron spectrum-averaged cross section in several benchmark neutron fields is given in Table 3 of Practice
E261. Sources for the latest recommended cross sections are given in Guide E1018. In the case of the U(n,f)F.P. reaction, the
recommended cross section source is the ENDF/B-VI release 8 cross section (MAT = 9237) (58).Fig. 1 shows a plot of the
recommended cross section versus neutron energy for the fast-neutron reaction U(n,f)F.P.
FIG. 1 ENDF/B-VI Cross Section Versus Energy for the U(n,f)F.P. Reaction
The boldface numbers in parentheses refer to the list of references appended to this test method.
E704 − 19
NOTE 1—The data is taken from the Evaluated Nuclear Data File, ENDF/B-VI, rather than the later ENDF/B-VII. Thi
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