VGB POWERTECH 5 (2021) - International Journal for Generation and Storage of Electricity and Heat

Radioactivity calculation for retired nuclear power plant VGB PowerTech 5 l 2021
Tab. 2. 47 energy group and group-wise microscopic cross-sections for the reactions of interest.
Energy
Group
Lower Group Energy
(MeV)
Cross-Section (barn)
63 Cu(n,α) 60 Co 54 Fe(n,p) 54 Mn 58 Ni(n,p) 58 Co
1 1.42E+01 3.54E-02 2.62E-01 2.60E-01
2 1.22E+01 4.34E-02 4.04E-01 4.70E-01
3 1.00E+01 3.64E-02 4.70E-01 5.92E-01
4 8.61E+00 2.68E-02 4.82E-01 6.23E-01
5 7.41E+00 1.81E-02 4.82E-01 6.25E-01
6 6.07E+00 9.87E-03 4.78E-01 6.05E-01
7 4.97E+00 3.25E-03 4.34E-01 5.09E-01
8 3.68E+00 5.75E-04 3.13E-01 3.81E-01
9 3.01E+00 4.45E-05 1.93E-01 2.45E-01
10 2.73E+00 8.14E-06 1.33E-01 1.71E-01
11 2.47E+00 2.99E-06 7.87E-02 1.25E-01
12 2.37E+00 9.39E-07 5.66E-02 9.66E-02
13 2.35E+00 8.18E-07 5.12E-02 8.85E-02
14 2.23E+00 6.74E-07 4.49E-02 7.91E-02
15 1.92E+00 2.47E-07 2.93E-02 5.07E-02
16 1.65E+00 1.37E-08 8.87E-03 2.78E-02
17 1.35E+00 – 2.90E-03 1.46E-02
18 1.00E+00 – 7.32E-04 5.61E-03
19 8.21E-01 – 8.69E-05 1.29E-03
20 7.43E-01 – 6.56E-06 8.93E-04
21 6.08E-01 – 2.64E-07 5.21E-04
22 4.98E-01 – – 1.77E-04
23 3.69E-01 – – –
24 2.98E-01 – – –
25 1.83E-01 – – –
26 1.11E-01 – – –
27 6.74E-02 – – –
28 4.09E-02 – – –
29 3.18E-02 – – –
30 2.61E-02 – – –
31 2.42E-02 – – –
32 2.18E-02 – – –
33 1.50E-02 – – –
34 7.10E-03 – – –
35 3.36E-03 – – –
36 1.59E-03 – – –
37 4.54E-04 – – –
38 2.14E-04 – – –
39 1.01E-04 – – –
40 3.73E-05 – – –
41 1.07E-05 – – –
42 5.04E-06 – – –
43 1.86E-06 – – –
44 8.76E-07 – – –
45 4.14E-07 – – –
46 1.00E-07 – – –
47 1.00E-10 – – –
cross section data set produced specifically
for light water reactor application. In
this study, anisotropic scattering was treated
with a P3 Legendre expansion and angular
discretization was modeled with an
S10 order of angular quadrature.
(F i g u r e 2 ) shows the three dimensional
neutron transport calculation model used
in this study. (F i g u r e 3 ) shows the plan
view of reactor geometry at the core midplane.
A single octant depicts the arrangement
of thermal shield and surveillance
capsule attachments. In addition to the
core, reactor internals, pressure vessel and
primary biological shield, the models developed
for these octant geometries also
include explicit representations of the surveillance
capsules, the pressure vessel cladding,
the pressure vessel reflective insulation,
and the reactor cavity liner plate.
Fig. 2. R----Z geometry for neutron transport
calculations.
Fig. 3. Mid-plane octant geometry for neutron
transport calculations.
From a neutronic standpoint, the inclusion
of the surveillance capsules and associated
support structure in the analytical model is
significant. Because the presence of the
capsules and structure has a marked impact
on the magnitude of the neutron flux
and on the relative neutron and gamma ray
spectra at dosimetry locations within the
capsules, a meaningful evaluation of the
internal capsule radiation environment
can be made only when these perturbation
effects are properly accounted for in the
analysis.
In developing the R-θ-Z analytical models
of the reactor geometry shown in (F i g -
u r e 2 ), nominal design dimensions were
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