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Title: Evaluation of fission product worth margins in PWR spent nuclear fuel burnup credit calculations.

Abstract

Current criticality safety calculations for the transportation of irradiated LWR fuel make the very conservative assumption that the fuel is fresh. This results in a very substantial overprediction of the actual k{sub eff} of the transportation casks; in certain cases, this decreases the amount of spent fuel which can be loaded in a cask, and increases the cost of transporting the spent fuel to the repository. Accounting for the change of reactivity due to fuel depletion is usually referred to as ''burnup credit.'' The US DOE is currently funding a program aimed at establishing an actinide only burnup credit methodology (in this case, the calculated reactivity takes into account the buildup or depletion of a limited number of actinides). This work is undergoing NRC review. While this methodology is being validated on a significant experimental basis, it implicitly relies on additional margins: in particular, the absorption of neutrons by certain actinides and by all fission products is not taken into account. This provides an important additional margin and helps guarantee that the methodology is conservative provided these neglected absorption are known with reasonable accuracy. This report establishes the accuracy of fission product absorption rate calculations: (1) the analysis of Europeanmore » fission product worth experiments demonstrates that fission product cross-sections available in the US provide very good predictions of fission product worth; (2) this is confirmed by a direct comparison of European and US cross section evaluations; (3) accuracy of Spent Nuclear Fuel (SNF) fission product content predictions is established in a recent ORNL report where several SNF isotopic assays are analyzed; and (4) these data are then combined to establish in a conservative manner the fraction of the predicted total fission product absorption which can be guaranteed based on available experimental data.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Argonne National Lab., IL (US)
Sponsoring Org.:
US Department of Energy (US)
OSTI Identifier:
12014
Report Number(s):
ANL-FRA-1998-1
TRN: US0102327
DOE Contract Number:  
W-31109-ENG-38
Resource Type:
Technical Report
Resource Relation:
Other Information: PBD: 17 Feb 1999
Country of Publication:
United States
Language:
English
Subject:
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; 42 ENGINEERING; PWR TYPE REACTORS; BURNUP; CRITICALITY; CROSS SECTIONS; FISSION PRODUCTS; SPENT FUELS; SAFETY ANALYSIS; SPENT FUEL CASKS; TRANSPORT; REACTIVITY WORTHS

Citation Formats

Blomquist, R.N., Finck, P.J., Jammes, C., and Stenberg, C.G.. Evaluation of fission product worth margins in PWR spent nuclear fuel burnup credit calculations.. United States: N. p., 1999. Web. doi:10.2172/12014.
Blomquist, R.N., Finck, P.J., Jammes, C., & Stenberg, C.G.. Evaluation of fission product worth margins in PWR spent nuclear fuel burnup credit calculations.. United States. doi:10.2172/12014.
Blomquist, R.N., Finck, P.J., Jammes, C., and Stenberg, C.G.. Wed . "Evaluation of fission product worth margins in PWR spent nuclear fuel burnup credit calculations.". United States. doi:10.2172/12014. https://www.osti.gov/servlets/purl/12014.
@article{osti_12014,
title = {Evaluation of fission product worth margins in PWR spent nuclear fuel burnup credit calculations.},
author = {Blomquist, R.N. and Finck, P.J. and Jammes, C. and Stenberg, C.G.},
abstractNote = {Current criticality safety calculations for the transportation of irradiated LWR fuel make the very conservative assumption that the fuel is fresh. This results in a very substantial overprediction of the actual k{sub eff} of the transportation casks; in certain cases, this decreases the amount of spent fuel which can be loaded in a cask, and increases the cost of transporting the spent fuel to the repository. Accounting for the change of reactivity due to fuel depletion is usually referred to as ''burnup credit.'' The US DOE is currently funding a program aimed at establishing an actinide only burnup credit methodology (in this case, the calculated reactivity takes into account the buildup or depletion of a limited number of actinides). This work is undergoing NRC review. While this methodology is being validated on a significant experimental basis, it implicitly relies on additional margins: in particular, the absorption of neutrons by certain actinides and by all fission products is not taken into account. This provides an important additional margin and helps guarantee that the methodology is conservative provided these neglected absorption are known with reasonable accuracy. This report establishes the accuracy of fission product absorption rate calculations: (1) the analysis of European fission product worth experiments demonstrates that fission product cross-sections available in the US provide very good predictions of fission product worth; (2) this is confirmed by a direct comparison of European and US cross section evaluations; (3) accuracy of Spent Nuclear Fuel (SNF) fission product content predictions is established in a recent ORNL report where several SNF isotopic assays are analyzed; and (4) these data are then combined to establish in a conservative manner the fraction of the predicted total fission product absorption which can be guaranteed based on available experimental data.},
doi = {10.2172/12014},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Feb 17 00:00:00 EST 1999},
month = {Wed Feb 17 00:00:00 EST 1999}
}

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