Benchmarking ENDF/B-VII.0

Journal Article · Fri Dec 15 00:00:00 EST 2006 · Nuclear Data Sheets

DOI:https://doi.org/10.1016/j.nds.2006.11.002· OSTI ID:20900960

Marck, Steven C. van der ^[1]

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1. Nuclear Research and Consultancy Group NRG, P.O. Box, 1755 ZG Petten (Netherlands). E-mail: [e-mail]

The new major release VII.0 of the ENDF/B nuclear data library has been tested extensively using benchmark calculations. These were based upon MCNP-4C3 continuous-energy Monte Carlo neutronics simulations, together with nuclear data processed using the code NJOY. Three types of benchmarks were used, viz., criticality safety benchmarks (fusion) shielding benchmarks, and reference systems for which the effective delayed neutron fraction is reported. For criticality safety, more than 700 benchmarks from the International Handbook of Criticality Safety Benchmark Experiments were used. Benchmarks from all categories were used, ranging from low-enriched uranium, compound fuel, thermal spectrum ones (LEU-COMP-THERM), to mixed uranium-plutonium, metallic fuel, fast spectrum ones (MIX-MET-FAST). For fusion shielding many benchmarks were based on IAEA specifications for the Oktavian experiments (for Al, Co, Cr, Cu, LiF, Mn, Mo, Si, Ti, W, Zr), Fusion Neutronics Source in Japan (for Be, C O, Fe, Pb), and Pulsed Sphere experiments at Lawrence Livermore National Laboratory (for {sup 6}Li, {sup 7}Li, Be, C, N, O, Mg, Al, Ti, Fe, Pb, D{sub 2}O, H{sub 2}O, concrete, polyethylene and teflon). For testing delayed neutron data more than thirty measurements in widely varying systems were used. Among these were measurements in the Tank Critical Assembly (TCA in Japan) and IPEN/MB-01 (Brazil), both with a thermal spectrum, and two cores in Masurca (France) and three cores in the Fast Critical Assembly (FCA, Japan), all with fast spectra. In criticality safety, many benchmarks were chosen from the category with a thermal spectrum, low-enriched uranium, compound fuel (LEU-COMP-THERM), because this is typical of most current-day reactors, and because these benchmarks were previously underpredicted by as much as 0.5% by most nuclear data libraries (such as ENDF/B-VI.8, JEFF-3.0). The calculated results presented here show that this underprediction is no longer there for ENDF/B-VII.0. The average over 257 benchmarks deviates only 0.017% from the measured benchmark value. Moreover, no clear trends (with e.g. enrichment, lattice pitch, or spectrum) have been observed. Also for fast spectrum benchmarks, both for intermediately or highly enriched uranium and for plutonium, clear improvements are apparent from the calculations. The results for bare assemblies have improved, as well as those with a depleted or natural uranium reflector. On the other hand, the results for plutonium solutions (PU-SOL-THERM) are still high, on average (over 120 benchmarks) roughly 0.6%. Furthermore there still is a bias for a range of benchmarks based on cores in the Zero Power Reactor (ANL) with sizable amounts of tungsten in them. The results for the fusion shielding benchmarks have not changed significantly, compared to ENDF/B-VI.8, for most materials. The delayed neutron testing shows that the values for both thermal and fast spectrum cases are now well predicted, which is an improvement when compared with ENDF/B-VI.8.

• OSTI ID: 20900960
• Journal Information: Nuclear Data Sheets, Vol. 107, Issue 12; Other Information: DOI: 10.1016/j.nds.2006.11.002; PII: S0090-3752(06)00088-3; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0090-3752
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
BENCHMARKS
COMPUTERIZED SIMULATION
CONCRETES
CRITICALITY
DELAYED NEUTRON FRACTION
DELAYED NEUTRONS
EVALUATED DATA
HEAVY WATER
HIGHLY ENRICHED URANIUM
LITHIUM 6
LITHIUM 7
LITHIUM FLUORIDES
MONTE CARLO METHOD
NATURAL URANIUM
NUCLEAR DATA COLLECTIONS
NUCLEAR FUELS
PLUTONIUM
SHIELDING
SOLUTIONS
TEFLON
TUNGSTEN