Program - Brookhaven National Laboratory

DE 7 5:30 PM
Application of the PSI-NUSS Tool for Estimation of Nuclear Data Related K-eff
Uncertainties for the OCED/NEA WPNCS UACSA Phase 1 Benchmark
Ting Zhu, Alexander Vasiliev, Hakim Ferroukhi
Paul Scherrer Institut
At the Paul Scherrer Institut, a methodology for the propagation of nuclear data uncertainties into criticality
safety calculations with the Monte Carlo code MCNP(X), titled as PSI-NUSS, is under development.
The primary purpose is to provide a complementary and innovative option for the assessment of nuclear
data related uncertainties versus the traditional approach commonly applied in many state-of-the-art criticality
safety evaluation (CSE) methodologies and which relies on estimating biases/uncertainties based on
comprehensive validation studies against representative critical benchmark experiments. A description of
the PSI-NUSS methodology, as well as its assessment against the more rigorous and theoretically grounded
Total Monte Carlo methodology developed at NRG, is presented in an accompanying paper. In the present
paper, the PSI-NUSS methodology is applied to quantify nuclear data uncertainties for the OCED/NEA
WPNCS UACSA Phase 1 benchmark. One underlying reason is that the previous PSI CSE contribution for
this benchmark was based on using a more conventional approach involving ’engineering guesses’ in order to
estimate uncertainties in the calculated effective multiplication factor caused by nuclear data uncertainties.
Therefore, as the PSI-NUSS methodology aims precisely at integrating a more rigorous treatment of these
types of uncertainties for CSE, its application to the UACSA benchmark Phase I is conducted here with
two main objectives. First, the nuclear-data related uncertainty component is estimated and compared
to results obtained by other participants using different codes/libraries and methodologies. Secondly, the
estimated k-eff uncertainty is compared to the results obtained with the previously employed approach.
Outlook for further verification and validation studies for the PSI-NUSS methodology is presented and the
eventual updates of the overall PSI CSE methodology are discussed.
DE 8 5:45 PM
SENS1D: A New Sensitivity And Uncertainty Analysis Code
Wenming Wang,Haicheng Wu
China Nuclear Data Center, China Institute of Atomic Energy
As the development of modern reactor technology, the need of safety and reliability plays an increasing role
of reactor design and maintainance, which calls for more precise nuclear data and more accurate validation
of uncertainty analysis. In order to quantify the design uncertainty of key integral parameters due to
input fundamental nuclear data, the perturbation method was applied to the transport process, basing
on which many codes coupled with different transport system were developed from late 1970s, such as
FORSS system, SUSD3D and TSUNAMI in the latest SCALE 6 system. In China Nuclear Data Center,
written in Fortran95, a new S/U analysis code SENS1D was developed, coupled with XSDRN and ANISN
basing on 1st order perturbation theory and MCNP with the perturbation card method. SENS1D has the
ability to analyze the sensitivity and uncertainty of keff by nuclear and reaction, which includes all main
reaction channel such as total, fission, absorption (all neutron disappearing channel), scattering (elastic
and in-elastic), nu-bar and fission spectrum. As testing case, SENS1D were implemented into several 1-
D benchmark facilities, such as Jezebel, Godiva and Flattop. The group constants were generated from
CENDL3.1 and ENDF/B-VII, with the covariance data from JENDL4. Both XSDRN and ANISN were
used to offer neutron flux information. Coupled with MCNP code, SENS1D was also used for the S/U
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