vgbe energy journal 10 (2022) - International Journal for Generation and Storage of Electricity and Heat

Analysis of VERA core physics benchmark problems
Reference
Calsulated
% Error
Fig. 2. Comparison of relative power distribution for 2A assembly
Reference
Calsulated
% Error
Fig. 3. Comparison of relative power distribution for 2F assembly.
Reference
Calsulated
% Error
Fig. 4. Comparison of relative power distribution for 2G assembly
Reference
Calsulated
% Error
Fig. 5. Comparison of relative power distribution for 2K assembly.
semblies (FAs) with various configuration
and temperatures are analyzed. The calculation
conditions are given in Ta b l e 2 . Fuel
assemblies 2A to 2D are analyzed with varying
temperature conditions from 565 K to
1,200 K. The rest of problems have the same
temperature conditions (600 K). The simulated
results of various VERA assemblies are
given in Ta b l e 3 , which shows that the
maximum relative error in multiplication
factor is -330 pcm observed in 2G assembly.
It is clear from the comparison that error in
reactivity increases with increase in temperature
for no Pyrex assemblies and increase
in the number Pyrex rods. It is observed that
the maximum error is in AIC controlled assemblies.
For the Gadolinium (Gd) poisoned
assemblies, the reactivity difference is about
100 pcm, which is quite reasonable agreement
with reference value. The comparison
shows quite favorable agreement with the
reference which implies that DRAGON can
be confidently applied to two-dimension
Pressurized Water Reactors (PWRs) lattice
problems. The pin power distribution for the
varying temperature conditions (2A to 2D)
are calculated, but only the pin power distribution
for the no Pyrex assembly of 2A is
shown in F i g u r e 2 . In the no Pyrex cases,
the pin powers are close to the reference
with the maximum error of 0.34 %. The calculated,
reference power distribution and
percentage error for the assemblies with 12
and 24 Pyrex were evaluated. F i g u r e 3
show the relative error in assembly 2F (with
24 Pyrex rods). The percent relative errors
are in acceptable range with the maximum
value of 1.22 %. For the AIC controlled case,
the maximum underestimation is 2.75 % as
shown in F i g u r e 4 . For 2 K zoned assembly
with 24 Pyrex rods, the maximum overpower
estimation is 1.29 % as shown in F i g -
u r e 5 . In case of Gd based fuel, the 3.43 %
underestimation in power occurs in the Gd
pins in the assembly with 24 Gadolinia pins.
The pin power distribution for the Gd based
fuels show quite good agreement as shown
in Figure 6.
4.3 Problem #5-2D: 2D HZP BOC
Quarter Core
In this VERA benchmark, the HZP (Hot Zero
Power) two-dimensional reactor core is
analyzed to predict the criticality, power distribution
and control rod worth at BOL (Beginning
of Life) isothermal conditions. Ta -
b l e 4 shows the comparison of reactivity
for uncontrolled and controlled configuration.
The reactivity is underestimated in the
AIC controlled core by 663 pcm which is in
the acceptable range for the core configuration.
F i g u r e 7 and F i g u r e 8 show the
vgbe energy journal 10 · 2022 | 57