ASTM E321-96(2012)
Standard Test Method for Atom Percent Fission in Uranium and Plutonium Fuel (Neodymium-148 Method)

Standard No.

ASTM E321-96(2012)

Release Date

1996

Published By

American Society for Testing and Materials (ASTM)

Status

Be replaced

Replace By

ASTM E321-20

Latest

ASTM E321-20

Scope

The burnup of an irradiated nuclear fuel can be determined from the amount of a fission product formed during irradiation. Among the fission products, ¹⁴⁸Nd has the following properties to recommend it as an ideal burnup indicator: (1) It is not volatile, does not migrate in solid fuels below their recrystallization temperature, and has no volatile precursors. (2) It is nonradioactive and requires no decay corrections. ( 3) It has a low destruction cross section and formation from adjacent mass chains can be corrected for. (4) It has good emission characteristics for mass analysis. (5) Its fission yield is nearly the same for ²³⁵U and ²³⁹Pu and is essentially independent of neutron energy (6). (6) It has a shielded isotope, ¹⁴²Nd, which can be used for correcting natural Nd contamination. (7) It is not a normal constituent of unirradiated fuel.

The analysis of ¹⁴⁸Nd in irradiated fuel does not depend on the availability of preirradiation sample data or irradiation history. Atom percent fission is directly proportional to the ¹⁴⁸Nd-to-fuel ratio in irradiated fuel. However, the production of ¹⁴⁸Nd from ¹⁴⁷Nd by neutron capture will introduce a systematic error whose contribution must be corrected for. In power reactor fuels, this correction is relatively small. In test reactor irradiations where fluxes can be very high, this correction can be substantial (see Table 1).

The test method can be applied directly to U fuel containing less than 0.5 % initial Pu with 1 to 100 GW days/metric ton burnup. For fuel containing 5 to 50 % initial Pu, increase the Pu content by a factor of 10 to 100, respectively in both reagents 5.3 and 5.4.

TABLE 1 K Factors to Correct ¹⁴⁸Nd for ¹⁴⁷Nd Thermal Neutron Capture^A

ASTM E321-96(2012) Referenced Document

• ASTM D1193 Standard Specification for Reagent Water*， 1999-04-19 Update
• ASTM E180 Standard Practice for Determining the Precision of ASTM Methods for Analysis and Testing of Industrial and Specialty Chemicals*， 1999-04-19 Update
• ASTM E244 Test Method for Atom Percent Fission in Uranium and Plutonium Fuel (Mass Spectrometric Method) (Withdrawn 2001)*， 2021-03-02 Update
• ASTM E267 Standard Test Method for Uranium and Plutonium Concentrations and Isotopic Abundances

ASTM E321-96(2012) history

• 2020 ASTM E321-20 Standard Test Method for Atom Percent Fission in Uranium and Plutonium Fuel (Neodymium-148 Method)
• 1996 ASTM E321-96(2012) Standard Test Method for Atom Percent Fission in Uranium and Plutonium Fuel (Neodymium-148 Method)
• 1996 ASTM E321-96(2005) Standard Test Method for Atom Percent Fission in Uranium and Plutonium Fuel (Neodymium-148 Method)
• 1996 ASTM E321-96 Standard Test Method for Atom Percent Fission in Uranium and Plutonium Fuel (Neodymium-148 Method)

---

Copyright ©2024 All Rights Reserved

Total Neutron Flux, ϕ (neutrons/cm2/s)	Total Neutron Exposure, ϕI (neutrons/cm 2)
	1 × 10 20	3 × 10 20	1 × 10 21	2 × 10 21	3 × 10 21
3 × 101 2	0.9985	0.9985	0.9985	0.9985	0.9985
1 × 101 3	0.9956	0.9952	0.9950	0.9950	0.9950
3 × 101 3	0.9906