JAEA-Conf 2011-002 - 日本原子力研究開発機構
JAEA-Conf 2011-002 - 日本原子力研究開発機構
JAEA-Conf 2011-002 - 日本原子力研究開発機構
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
- PU-MET-FAST-001 (Jezebel): a bare sphere of plutonium-239 metal.<br />
- U233-MET-FAST-001 (Jezebel-233): a bare sphere of uranium-233 metal.<br />
- HEU-MET-FAST-028 (Flattop-U): a highly enriched uranium sphere reflected by normal<br />
uranium.<br />
- PU-MET-FAST-006 (Flattop-Pu): a plutonium sphere reflected by normal uranium.<br />
- U233-MET-FAST-006 (Flattop-233): a uranium-233 sphere reflected by normal uranium.<br />
- HEU-MET-FAST-003-011: a highly enriched uranium sphere reflected by tungsten-carbide.<br />
- HEU-MET-FAST-021: a highly enriched uranium sphere reflected by iron.<br />
- PU-MET-FAST-040: a plutonium sphere reflected by copper.<br />
- HEU-MET-FAST-027: a highly enriched uranium sphere reflected by lead.<br />
70-group sensitivity coefficients are derived with forward and adjoint neutron fluxes<br />
calculated by using an in-house discrete ordinates neutron transport code. In the discrete<br />
ordinates neutron transport calculations, Legendre coefficients of scattering matrices are<br />
accounted for up to the fifth order, and the 32-point double Gaussian angular quadrature set is<br />
used. Effective cross sections used for the neutron transport calculations are obtained by using<br />
the SLAROM-UF code [2] and UFLIB-J4.0 based on JENDL-4.0. Figure 1 shows a sensitivity of<br />
the HEU-MET-FAST-028 criticality to Legendre coefficients of elastic scattering cross sections of<br />
uranium-238.<br />
Library effects are calculated according to Eq.(1) with the sensitivity coefficients and the<br />
infinite dilution cross sections stored in UFLIB. JENDL-4.0 is treated as a base library, and<br />
differences of the other libraries to JENDL-4.0 are evaluated.<br />
4. Result of sensitivity analysis<br />
Table 1 shows differences in criticalities due to differences in each order of Legendre coefficient<br />
of elastic scattering matrices. Large effects over 0.001 are written in a bold style.<br />
While library effects due to differences in higher order Legendre coefficients are generally<br />
small, non-negligible effects are observed in PU-MET-FAST-006 with JENDL-3.3 and<br />
ENDF/B-VII.0, and HEU-MET-FAST-021 with all the libraries. The former is due to the<br />
difference in the uranium-238 data and the latter is due to the difference in the iron-56 data.<br />
Please remember that the above library effect calculations are carried out by using infinite<br />
dilution cross sections. Since medium-heavy nuclides such as iron-56 have resonance cross<br />
sections in the energy range above 0.1MeV, which is a dominant range in the present benchmark<br />
systems, the resonance self-shielding effect should be considered for accurate evaluation of<br />
library effects. Thus, a library effect calculation is again carried out for HEU-MET-FAST-021<br />
with shielded cross sections. In the resonance self-shielding factor calculation, background cross<br />
sections for iron isotopes are set at 50, 0.5, 150 and 1,000 barns for iron-54, -56, -57 and -58,<br />
respectively. These values are evaluated for the reflector medium of HEU-MET-FAST-021. In<br />
this case, a library effect is calculated with the following equation:<br />
<br />
<br />
k , LIB1<br />
k S<br />
l , g g '<br />
n l 1 g g'<br />
<br />
k , LIB1<br />
S l , g g '<br />
n l1 g g'<br />
LIB 2 LIB1<br />
a a <br />
f<br />
<br />
<br />
<br />
l,<br />
g g '<br />
LIB2<br />
t1,<br />
g<br />
<br />
LIB 2<br />
l,<br />
g<br />
g '<br />
l,<br />
g<br />
g '<br />
f<br />
LIB 2<br />
g<br />
<strong>JAEA</strong>-<strong>Conf</strong> <strong>2011</strong>-<strong>002</strong><br />
f<br />
<br />
LIB1<br />
g<br />
<br />
LIB 2<br />
0,<br />
g<br />
g '<br />
LIB1<br />
0,<br />
g<br />
g '<br />
f<br />
<br />
LIB1<br />
t1,<br />
g<br />
<br />
<br />
LIB1<br />
l,<br />
g<br />
g '<br />
f<br />
LIB1<br />
g<br />
<br />
LIB1<br />
0,<br />
g<br />
g '<br />
<br />
<br />
f<br />
<br />
LIB1<br />
g<br />
<br />
LIB1<br />
0,<br />
g<br />
g '<br />
,