ASTM E219-80(1995)

Test Method for Atom Percent Fission in Uranium Fuel (Radiochemical Method) (Withdrawn 2001)

SCOPE
1.1 This test method covers the determination of U atom percent fission that has occurred in U fuel from analysis of the  137 Cs to U ratio after irradiation.  
1.2 The test method is applicable to high-density, clad U fuel (metal, alloy, ceramic compound) in which no separation of Cs and U has occurred.  
1.3 The test method is best applied to fuels that have aged several months since irradiation. In such material, the 13-day  136 Cs activity is reduced to a small amount through decay (3).  
1.4 The test method should be restricted to low-exposure samples in which the activity of  134 Cs is less than that of  137 Cs. Cesium-134 is produced by neutron capture on fission product  133 Cs and grows at a rate proportional to the square of the exposure. This capture process limits the test method to samples exposed to less than 0.6 X 10  nvt. This exposure corresponds to burnups of 12 gigawatt days per metric ton of uranium (GWD/MTU) in Yankee Core I, and 5 GWD/ MTU in Dresden Core I. Samples with higher exposures may require the use of a lithium-drifted germanium detector to obtain adequate resolution between  134 Cs and  137 Cs. The use of such a detector will extend the range of this test method by a factor of about 2. Mass spectrometric isotope dilution analysis of  137 Cs with  133 Cs as the isotopic diluent would also overcome  134 Cs interference.  
1.5 The test method is best applied to fuels where overheating has not caused center melting or grain growth, since high temperatures cause  137 Cs to distill from the fuel and deposit on cooler regions, such as the cladding. Therefore, cladding should be leached in the dissolver solution or dissolved with the uranium to maintain the true ratio of fission product  137 Cs to U. Alternatively, burnup in a maximum flux region of a fuel element can be obtained from analyzing a low-flux region of the element. The burnup measured in this position can be related to the burnup in the peak-flux position by a gamma scan of the element. A gamma scan usually represents the distribution of zirconium-95 and is a reflection of the fission distribution integrated over only the most recent months. This is not always a serious disadvantage, since such studies may be made after short irradiations.  
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.

General Information

• Status: Withdrawn
• Publication Date: 26-Feb-1997
• Withdrawal Date: 09-Jun-2001
• ICS: 27.120.30 - Fissile materials and nuclear fuel technology
• Technical Committee: C26 - Nuclear Fuel Cycle
• Drafting Committee: C26.05 - Methods of Test

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: E 219 – 80 (Reapproved 1995)
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Method for
Atom Percent Fission in Uranium Fuel (Radiochemical
1
Method)
This standard is issued under the fixed designation E 219; 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.
INTRODUCTION
Uranium atom percent fission in a nuclear fuel is frequently determined by measurement of a fission
2
product to uranium (U) ratio in the irradiated U fuel (1-7).
137
Among radioactive fission products, cesium-137 ( Cs) was among the first used for estimation of
fuel burnup. It has a reasonably well-known decay scheme, a low capture cross section, a long
136
half-life, a very low yield from Cs by neutron capture, and a high-fission yield which is fairly
accurately known and not greatly affected by the type of fissionable material or the neutron spectrum.
Disadvantages are found in the volatility of Cs and its precursors at fuel operating temperature (which
134 136
gives rise to migration within the fuel), interference in counting from Cs and Cs, some
uncertainty in physical constants, and required knowledge of irradiation history.
Although this test method is of historical interest, test methods based on mass spectrometry are
preferred as a basis for fuel-warranty settlements because they are more accurate.
137 133
1. Scope Cs with Cs as the isotopic diluent would also overcome
134
Cs interference.
1.1 This test method covers the determination of U atom
1.5 The test method is best applied to fuels where overheat-
percent fission that has occurred in U fuel from analysis of the
137
ing has not caused center melting or grain growth, since high
Cs to U ratio after irradiation.
137
temperatures cause Cs to distill from the fuel and deposit on
1.2 The test method is applicable to high-density, clad U
cooler regions, such as the cladding. Therefore, cladding
fuel (metal, alloy, ceramic compound) in which no separation
should be leached in the dissolver solution or dissolved with
of Cs and U has occurred.
137
the uranium to maintain the true ratio of fission product Cs
1.3 The test method is best applied to fuels that have aged
to U. Alternatively, burnup in a maximum flux region of a fuel
several months since irradiation. In such material, the 13-day
136
element can be obtained from analyzing a low-flux region of
Cs activity is reduced to a small amount through decay (3).
the element. The burnup measured in this position can be
1.4 The test method should be restricted to low-exposure
134
related to the burnup in the peak-flux position by a gamma scan
samples in which the activity of Cs is less than that of
137
of the element. A gamma scan usually represents the distribu-
Cs. Cesium-134 is produced by neutron capture on fission
133
tion of zirconium-95 and is a reflection of the fission distribu-
product Cs and grows at a rate proportional to the square of
tion integrated over only the most recent months. This is not
the exposure. This capture process limits the test method to
1
always a serious disadvantage, since such studies may be made
samples exposed to less than 0.6 3 10 nvt. This exposure
after short irradiations.
corresponds to burnups of 12 gigawatt days per metric ton of
1.6 This standard does not purport to address all of the
uranium (GWD/MTU) in Yankee Core I, and 5 GWD/MTU in
safety concerns, if any, associated with its use. It is the
Dresden Core I. Samples with higher exposures may require
responsibility of the user of this standard to establish appro-
the use of a lithium-drifted germanium detector to obtain
134 137
priate safety and health practices and determine the applica-
adequate resolution between Cs and Cs. The use of such
bility of regulatory limitations prior to use.
a detector will extend the range of this test method by a factor
of about 2. Mass spectrometric isotope dilution analysis of
2. Referenced Documents
2.1 ASTM Standards:
E 177 Practice for Use of the Terms Precision and Bias in
1
3
This test method is under the jurisdiction of ASTM Committee C-26 on Nuclear
ASTM Test Methods
Fuel Cycle.
E 180 Practice for Determining the Precision of ASTM
Current edition approved Sept. 26, 1980. Published November 1980. Originally
published as E 219 – 63 T. Last previous edition E 219 – 69 (1974).
2
The boldface numbers in parentheses refer to the list of references appended to
3
this test method. Annual Book of ASTM Standards, Vol 14.02.
1

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