Program - Brookhaven National Laboratory

transmuters, inclusive covariance data with respect to both the target nuclides and reactions are needed.
To meet this requirement, the Japanese Evaluated Nuclear Data Library (JENDL-4.0) [1], released in
2010, places much emphasis on the improvements of the covariance data; covariances for all reactions of
almost all nuclides, as well as reaction parameters, were newly evaluated and/or revised based on available
experimental data and theoretical calculations using the nuclear data evaluation codes. The objective of
this study is to derive the reactor physics parameters with total uncertainty on ADS and FR with the use
of the JENDL-4.0 cross-section and covariance data, and compare to the older one, JENDL-3.3. For ADS,
the basic concept investigated in Japan Atomic Energy Agency (JAEA) [2] was adopted, namely the 800
MWth lead-bismuth eutectic (LBE) cooled type ADS with nitride fuel (MA ratio: 63.7 wt%). For FR,
we selected the 3,600 MWth sodium-cooled type FR with MOX fuel (MA ratio: 5.0 wt%) based on the
concept investigated in the feasibility study in Japan [3]. As the reactor physics parameters, the criticality
(keff ), coolant void reactivity, and Doppler reactivity was analyzed. Then, to identify the cause of the
differences of the parameters between the two libraries, we analyezed differences by nuclies and reactions
with the use of the sensitivity coefficients calculated by the sensitivity calculation code, SAGEP [4]. We
also investigated nuclide- and reaction-wise uncertainties on the two reactors and compare the differences
of the uncertainties between JENDL-4.0 and JENDL-3.3.
[1] K. Shibata, O. Iwamoto, T. Nakagawa, et al., J. Nucl. Sci. and Technol., 48, 1, 1 (2011). [2] K.
Nishihara, K. Iwanaga, K. Tsujimoto, et al., J. Nucl. Sci. and Technol., 45, 8, 812 (2008). [3] Japan
Atomic Energy Agency, JAEA-Research 2006-042 (2006) [in Japanese]. [4] A. Hara, T. Takeda, and Y.
Kikuchi, JAERI-M 84-065 (1984) [in Japanese].
LC 4 4:40 PM
Propagation of Neutron Cross Section, Fission Yield, and Decay Data Uncertainties in
Depletion Calculations
J. S. Martínez Gonzälez, L. Gallner, W. Zwermann, F. Puente-Espel, O. Cabellos, K. Velkov, A. Pautz
Gesellschaft für Anlagen- und Reaktorsicherheit (GRS) mbH
A complete reactor physics study requires not only the calculation of the values of interest but the assessment
of their uncertainties arising from the nuclear data used. XSUSA represents a validated methodology
to propagate cross-section uncertainties and analyze their impact on reactor analysis. However, until
recently, it did not include the propagation of fission yields and decay constants uncertainties, relevant
magnitudes for burn-up calculations and isotopic predictions. We describe in this paper a technique to
propagate these fission yields and decay data uncertainties following the XSUSA procedure, that is, the
generation, from the basic nuclear data, of varied libraries to be used by SCALE6.1 for reactor calculations.
SCALE6.1 employs the ORIGEN-S module to perform depletion calculations. An automated process to
vary the ORIGEN-S fission yields and decay input libraries according to the uncertainties found in the
nuclear data files has been developed and applied to the ENDF/B-VII library. In order to study the impact
of the uncertainties on depletion calculations, a light water reactor pin cell model as defined in the
UAM Phase I Benchmark has been used. 1.000 depletion calculations were executed repeatedly using the
different varied libraries. Various cases have been studied, perturbing (1) the fission yield libraries, (2) the
decay libraries, (3) the neutron cross section libraries, and (4) all libraries simultaneously. This strategy
helps us to shed light on the separate and combined effect of their uncertainties on the multiplication
factors and isotopic content during the depletion cycle. It turns out that for the system under consideration,
the multiplication factor uncertainty is dominated by the neutron cross section uncertainties. For
certain isotopes, however, fission yield und decay data uncertainties may give significant contributions to
the uncertainties of the respective concentrations.
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