ASTM E393-96(2002)
(Test Method)Standard Test Method for Measuring Reaction Rates by Analysis of Barium-140 From Fission Dosimeters
Standard Test Method for Measuring Reaction Rates by Analysis of Barium-140 From Fission Dosimeters
SCOPE
1.1 This test method describes two procedures for the measurement of reaction rates by determining the amount of the fission product 140Ba produced by the non-threshold reactions 235U (n, f), 241Am (n, f), and 239Pu (n, f), and by the threshold reactions 238U (n, f), 237Np (n, f), and 232Th (n, f).
1.2 These reactions produce many fission products, among which is 140Ba, having a half-life of 12.752 days. 140Ba emits gamma rays of several energies; however, these are not easily detected in the presence of other fission products. Competing activity from other fission products requires that a chemical separation be employed or that the 140Ba activity be determined indirectly by counting its daughter product 140La. This test method describes both procedure (a), the nondestructive determination of 140Ba by the direct counting of 140La several days after irradiation, and procedure (b), the chemical separation of 140Ba and the subsequent counting of 140Ba or its daughter 140La.
1.3 With suitable techniques, fission neutron fluence rates can be measured in the range from 107 n (neutrons) cm2 s1 to approximately 10 15 n cm2 s1.
1.4 The measurement of time-integrated reaction rates with fission dosimeters by 140Ba analysis is limited by the half-life of 140Ba to irradiation times up to about six weeks.
1.5 The values stated in SI units are to be regarded as 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 and health practices and determine the applicability of regulatory limitations prior to use.
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Designation:E393–96 (Reapproved 2002)
Standard Test Method for
Measuring Reaction Rates by Analysis of Barium-140 From
Fission Dosimeters
This standard is issued under the fixed designation E393; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope Dioxide Powders and Pellets
D1193 Specification for Reagent Water
1.1 This test method describes two procedures for the
E170 Terminology Relating to Radiation Measurements
measurement of reaction rates by determining the amount of
and Dosimetry
the fission product Ba produced by the non-threshold reac-
235 241 239
E181 Test Methods for Detector Calibration and Analysis
tions U (n, f), Am (n, f), and Pu (n, f), and by the
238 237 232
of Radionuclides
threshold reactions U (n, f), Np (n, f), and Th (n, f).
E261 Practice for Determining Neutron Fluence Rate, Flu-
1.2 These reactions produce many fission products, among
140 140
ence, and Spectra by Radioactivation Techniques
which is Ba, having a half-life of 12.752 days. Ba emits
E704 Test Method for Measuring Reaction Rates by Ra-
gamma rays of several energies; however, these are not easily
dioactivation of Uranium-238
detected in the presence of other fission products. Competing
E705 Test Method for Measuring Reaction Rates By Ra-
activity from other fission products requires that a chemical
dioactivation of Neptunium-237
separationbeemployedorthatthe Baactivitybedetermined
E844 Guide for Sensor Set Design and Irradiation for
indirectly by counting its daughter product La. This test
Reactor Surveillance, E706 (IIC)
method describes both procedure (a), the nondestructive deter-
140 140
E944 Guide for Application of Neutron Spectrum Adjust-
mination of Ba by the direct counting of La several days
ment Methods in Reactor Surveillance, (IIA)
after irradiation, and procedure (b), the chemical separation of
E1005 TestMethodforApplicationandAnalysisofRadio-
140Ba and the subsequent counting of Ba or its daughter
metric Monitors for Reactor Vessel Surveillance, E706
140La.
(IIA)
1.3 With suitable techniques, fission neutron fluence rates
7 −2 −1
E1018 Guide for Application of ASTM Evaluated Cross
can be measured in the range from 10 n (neutrons) · cm ·s
15 −2 −1
Section Data File, Matrix E706 (IIB)
to approximately 10 n·cm ·s .
1.4 The measurement of time-integrated reaction rates with
3. Terminology
fission dosimeters by Ba analysis is limited by the half-life
140 3.1 Definitions:
of Ba to irradiation times up to about six weeks.
3.1.1 Refer to Terminology E170.
1.5 The values stated in SI units are to be regarded as
standard.
4. Summary of Test Method
1.6 This standard does not purport to address all of the
4.1 For nondestructive analysis, the fission dosimeter is
safety concerns, if any, associated with its use. It is the
allowed to cool for five days or more. The 1.596-MeV gamma
responsibility of the user of this standard to establish appro-
energy peak of La, which is the daughter product of the
priate safety and health practices and determine the applica-
140Ba, is then counted. This information, combined with the
bility of regulatory limitations prior to use.
decay constants for the La and the Ba, and the fission yield of
the Bagivesthereactionfissionrate.Whenthepropercross
2. Referenced Documents
section is used with the reaction rate, the equivalent fission
2.1 ASTM Standards:
fluence rate can be determined.
C697 TestMethodsforChemical,MassSpectrometric,and
4.2 For destructive analysis, the fission product Ba is
Spectrochemical Analysis of Nuclear-Grade Plutonium
separated from the irradiated fission dosimeter. The activity of
the Ba is determined by counting the 0.537 MeV gamma
ThistestmethodisunderthejurisdictionofASTMCommitteeE10onNuclear
Technology and Applications and is the direct responsibility of Subcommittee
E10.05 on Nuclear Radiation Metrology. Annual Book of ASTM Standards, Vol 12.01.
Current edition approved Jan. 10, 1996. Published March 1996. Originally Annual Book of ASTM Standards, Vol 11.01.
published as E393–84. Last previous edition E393–90. Annual Book of ASTM Standards, Vol 12.02.
Copyright ©ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA19428-2959, United States.
E393
TABLE 1 Recommended Cumulative Fission Yields for Ba
energypeak.Thisinformationisthenusedasin4.1togivethe
Production
reaction rate or the equivalent fission fluence rate.
Thermal or Fast
A,B
Fission Dosimeter Fission Yield,%
Neutron Field
5. Significance and Use
UT 5.84596 61%
5.1 Refer to Guide E844 for the selection, irradiation, and
F 5.98741 61%
quality control of neutron dosimeters. U F 5.8459661%
Pu T 5.3153861%
5.2 Refer to Practice E261 for a general discussion of the
F 5.37475 62%
measurement of neutron fluence rate and fluence. The neutron 237
Np F 5.47246 6 1.4%
Th F 7.87647 6 2.8%
spectrum must be known in order to measure neutron fluence
Am T 5.95468 6 2.8%
rates with a single detector.Also it is noted that cross sections
F 4.99172 66%
are continuously being reevaluated. The latest recommended
A
These ENDF/B-VI values are considered the best available data. The uncer-
cross sections and details on how they can be obtained are
tainties are expressed as a percentage of the fission yield.
B
discussed in Guide E1018. England, T. R., and Rider, B. F., ENDF-349 Evaluation and Compilation of
Fission Product Yields, LosAlamos National Laboratory, LosAlamos, NM, report
5.3 The reaction rate of a detector nuclide of known cross
LA-UR-94-3106, ENDF-349, October 1994.
section, when combined with information about the neutron
spectrum, permits the determination of the magnitude of the
6.2 ANaI(Tl) or Germanium Gamma-Ray Spectrometer,see
fluence rate impinging on the detector. Furthermore, if results
Test Methods E181 and E1005.
fromotherdetectorsareavailable,theneutronspectrumcanbe
6.3 Balance, providing the accuracy and precision required
defined more accurately. The techniques for fluence rate and
by the experiment.
fluence determinations are explained in Practice E261.
6.4 Centrifuge, clinical type, accommodating 50-mLcentri-
5.4 Ba is a radioactive nuclide formed as a result of
fuge tubes.
uranium fission.Although it is formed in fission of any heavy
6.5 Steam Bath.
atom,therelativeyieldwilldiffer.Recommendedfissionyields
6.6 Ice Bath.
for Ba production are given in Table 1. The direct (indepen-
6.7 Drying Oven.
dent) fission yield of the daughter product La, which is
6.8 Filter Cones.
counted, is given in Table 2. These independent fission yields
6.9 Fiberglass Filter Circles for filter cone.
are relatively low compared to the Ba cumulative fission
6.10 Centrifuge Tubes, 50-mL capacity.
yield and will not significantly affect the accuracy of the
6.11 Fine Sintered-Glass Crucibles.
nondestructive procedure and need not be considered.
140 140
5.5 The half-life of Ba is 12.752 days. Its daughter La
has a half-life of 1.6781 days. The comparatively long
TABLE 2 Independent Fission Yields for La Production
half-life of Ba allows the counting to be delayed several
Thermal or Fast
A,B
Fission Dosimeter Fission Yield, %
weeks after irradiation in a high-neutron field. However, to Neutron Field
235 −3
achieve maximum sensitivity the daughter product La
UT 5.25214 310 664%
−3
F 1.31401 310 664%
should be counted five to six days after the irradiation during
238 −5
U F 1.38004 310 664%
nondestructive analysis or five to six days after chemical
239 −3
Pu T 8.11109 310 664%
−2
separationifthelattertechniqueisused.Analternativemethod
F 1.17572 310 664%
140 237 −3
Np F 4.421 310 664%
after chemical separation is to count the Ba directly.
232 −5
Th F 2.71003 310 664%
5.6 Because of its 12.752 day half-life and substantial
241 −2
Am T 2.5758 310 664%
−2
fission yield, Ba is useful for irradiation times up to about
F 2.07034 310 632%
sixweeksinmoderateintensityfields.Oneirradiationcriterion A
These ENDF/B-VI values are considered the best available data. The uncer-
tainties are expressed as a percentage of the fission yield.
is that the number of fissions produced should be approxi-
B
9 England, T. R., and Rider, B. F., ENDF-349 Evaluation and Compilation of
mately 10 or greater for good counting statistics. Also, if the
Fission Product Yields, LosAlamos National Laboratory, LosAlamos, NM, report
irradiation time is substantially longer than six weeks the
LA-UR-94-3106, ENDF-349, October 1994.
neutron fluence rate determined will apply mainly to the
neutron field existing during the latter part of the irradiation.
7. Reagents and Materials
The Ba decay constant and yield are known more accurately
7.1 Purity of Fission Dosimeters—High purity uranium
than those of many fission products, so it is sometimes used as
plutonium, neptunium, and thorium in the form of alloy wire,
astandardorbasereactionwithwhichothermeasurementscan
foil, or oxide powder are available.
be normalized.
7.1.1 Target material shallbefurnishedwithacertificateof
analysis indicating any impurity concentrations.
6. Apparatus
7.1.2 Fission dosimeters shall be encapsulated in hermeti-
6.1 For nondestructive analysis the chemical separation
cally sealed containers to avoid loss of materials and for
equipment, materials, and reagents are not required.
health-hazard requirements.
5 6
Nuclear Wallet Cards, compiled by J. K. Tuli, National Nuclear Data Center, Vanadium-encapsulated monitors of high purity are available from Isotope
July 1990. Sales Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830.
E393
7.1.3 In thermal reactors threshold reaction dosimeters (for acid(36%)and10mLofammoniumacetatesolution.Bringto
238 237 232
example, U, Np, Th) shall be shielded from thermal boiling; add 5 mLof Na CrO solution dropwise with stirring;
2 4
neutrons with elemental, or compounds of, cadmium, gado- boil for 1 min with stirring. Cool the mixture to room
linium, or boron to prevent fission production from trace temperature and filter the precipitated barium chromate
235 239
quantities (>40 ppm) of U, and Pu and to suppress (BaCrO ) through a fine preweighed sintered-glass crucible.
buildup of interfering fissionable nuclides, for example, Pu 8.2.2 Washtheprecipitatethreetimeswith5-mLportionsof
238 238 238 237
in the U dosimeter, Np and Pu in the Np dosimeter, deionized water and three times with 5-mL portions of ethyl
233 232
and Uinthe Th dosimeter (see Guide E844). alcohol. Dry at 110°C, cool, and weigh. Calculate the barium
7.2 Purity of Reagents—Reagent grade chemicals shall be content as follows:
used in all tests. Unless otherwise indicated, it is intended that
Ba ,mg/mL 5 W/V 30.5421 (1)
~ !
all reagents shall conform to the specifications of the Commit-
tee onAnalytical Reagents of theAmerican Chemical Society, where:
where such specifications are available. Other grades may be W = milligrams of BaCrO , and
V = millilitres of carrier used.
used, provided it is first ascertained that the reagent is of
sufficiently high purity to permit its use without lessening the
9. Procedure for Nondestructive Analysis
accuracy of the determination.
7.3 Purity of Water—Unlessotherwiseindicated,references
9.1 Decide on the size and shape of sample to be irradiated
to water shall be understood to mean reagent water as defined
(see Guide E844).
by Type II of Specification D1193.
9.2 Weigh the sample to the accuracy and precision of the
7.4 Acetic Acid (36 %)—Dilute 360 mL of glacial acetic
experiment.
acid to 1 L with water.
9.3 Place the sample in a cadmium, gadolinium, or boron
7.5 Acetic Acid (6 %)—Dilute 60 mL of glacial acetic acid
cover if desired (see Guide E844). Seal into a capsule when
to 1 L with water.
required by safety considerations.
7.6 Ammonium Acetate Solution (231 g/L)—Dissolve 231 g
9.4 Irradiate the sample for a predetermined period of time.
of ammonium acetate in water and dilute to 1 L.
Record the beginning and end of the irradiation period. Take
7.7 Ammonium Hydroxide (sp gr 0.90)—Concentrated am-
into account any reactor power variation during the exposure
monium hydroxide (NH OH). period.
7.8 Barium Carrier (10 mg Ba/mL)—See Section 8.
9.5 Prior to counting, remove any covering material from
7.9 Ethyl Alcohol (95%). the dosimeter if it possesses interfering radionuclides. If
7.10 Hydrochloric Acid (sp gr 1.42)—Concentrated hydro-
encapsulated in quartz, copper, aluminum, or vanadium, the
chloric acid (HCl). encapsulating material need not be removed before counting.
+++
7.11 Iron Carrier (10 mg Fe /mL)—Dissolve 48.4 g of
9.6 After five days after the irradiation, count the La
FeCl ·6H O in 100 mL of water and dilute to 1 L with water. directlyonagamma-rayspectrometer(1.596-MeVgamma),or
3 2
7.12 Nitric Acid, Fuming.
by coincidence counting. Waiting exactly five days before
7.13 Nitric Acid (sp gr 1.42)—Concentrated nitric acid
counting is not required, but the La is at its maximum about
(HNO ).
134 h after the irradiation.
7.14 Sodium Carbonate Solution—Prepare a saturated so-
10. Procedure for Radiochemical Analysis
lution of sodium carbonate (Na CO ).
2 3
7.15 Sodium Chromate Solution (243 g/L)—Dissolve 243 g
10.1 Decideonthesizeandshapeofsampletobeirradiated
of sodium chromate (Na CrO ) in water and dilute to 1 L.
2 4 (see Guide E844).
7.16 Strontium Holdback Carrier (10 mg Sr/mL)—Dissolve
10.2 Weigh the sample to the accuracy and precision of the
24.2 g of Sr(NO ) in 1 L of water. Mix well, filter through a
3 2 experiment.
glass wool, and store in a polyethylene bottle.
10.3 Place the sample in a cadmium, gadolinium, or boron
7.17 Hydrofluoric Acid (HF) (1 N).
cover if desired (see Guide E844). Seal into a capsule when
required by safety considerations.
8. Preparation and Standardization of Barium Carrier
10.4 Irradiatethesampleforapredeterminedperiodoftime.
8.1 Preparation and Standardization of Barium Carrier:
Record the beginning and end of the irradiation period. Take
8.1.1 Dissolve 19.0 g of barium nitrate (Ba(NO ))in
3 2
into account any reactor power variation during the exposure
deionizedwateranddiluteto1L.Filterthroughglasswooland
period. Since the fission product to be extracted, Ba, has a
store in a polyethylene bottle.
12.752-day half-life, there can be a several-day waiting period
8.2 Standardization of Barium Carrier:
before the chemical separation is started.
8.2.1 Pipet 5.0 mL of the carrier solution into a 250-mL
10.5 Prior to counting, remove any covering material from
beakeranddilutetoa
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