3D BWR assembly transient example

Generating the steady state source distributions

% --- Asymmetric BWR assembly with Gd-pins -------------------

set title "Peach Bottom 2 from UAM, source generation "

include pins

include geometry

include materials

% --- Reflective boundary condition in XY:

set bc 2 2 1

% --- Neutron population and criticality cycles:

set pop 80000 1000000 200 1.0 100

% --- Geometry plots:

plot 3 1000 1000 0.0 
plot 3 1000 1000 0.0 -7.62 7.62 -7.62 7.62
plot 2 500 1500

% --- Total power for normalization:

set power 4.0000e+06

% --- Save source to "./source"-files

set savesrc "./source" 1.00 0.25 1 1 1

% --- Do not generate group constants

set gcu -1

% --- Do not use implicit capture, nxn, or fission

set impl 0 0 0

Time dependent simulation (no reactivity insertion)

% --- Asymmetric BWR assembly with Gd-pins -------------------

set title "Peach Bottom 2 from UAM, time dependent simulation"

include pins

include geometry

include materials

% --- Reflective boundary condition in XY:

set bc 2 2 1

% --- Increase size of precursor buffer

set pbuf 2

% --- Total power for normalization:

set power 4.0000e+06

% --- Set up time structures for simulation and detectors:

%     1 time interval for simulation (no population control)

tme simutime 2 1 0 1 % 

%     20 time bins for detector

tme dettime 2 20 0 1

% --- Neutron population:

% 10000 neutrons in 10 batches (1000 neutrons per batch)

set nps 4000000000 800000 simutime

set outp 10

% --- Link source (use point-wise precursor tracking)

set dynsrc "./source" 1

% --- Set up detectors
% --- Neutron population as a function of time

det 1 dr -15 void di dettime

% --- Fission energy deposition as a function of time

det 2 dr -8 void di dettime

% --- Do not generate group constants

set gcu -1

% --- Do not use implicit capture, nxn, or fission

set impl 0 0 0

Additional files

geometry

% --- Assembly lattice definition

lat 100 1  0.23876  0.23876 9 9 1.875
99 99 99 99 99 99 99 99 99
99  1  2  3  4  5  6  7 99
99  2  8  9 10 11 12 13 99
99  3  9 14 15 16 17 18 99
99  4 10 15 19 20 21 22 99
99  5 11 16 20 23 24 25 99
99  6 12 17 21 24 26 27 99
99  7 13 18 22 25 27 28 99
99 99 99 99 99 99 99 99 99 


% --- Outer channel (assembly pitch = 15.375):

surf  1  sqc   0.23876  0.23876      6.70306 % *
surf  2  sqc   0.23876  0.23876  6.90626

surf  4  pz -182.88 % Active stack length 365.76 cm
surf  5  pz  182.88 % Active stack length 365.76 cm

surf  9  cuboid  -7.62 7.62 -7.62 7.62 -250.0 250.0


% --- Cell definitions:

cell  3  101  fill 100  -1          % Pin lattice
cell  4  101  box        1          % Channel box wall

cell  5  0  fill 101   -2 4 -5      % assembly inside channel box outer wall
cell  6  0  moder       2 4 -5 -9   % Water outside channel box
cell  9  0  moder        -4    -9   % bottom reflector
cell 10  0  moder            5 -9   % top reflector

cell 99  0  outside             9   % Outside world