Spherical Tokamak#
This is characterized by a blanket that only goes around the outboard sides of the plasma and a center column that has no inboard breeding.
Spherical tokamak#
The spherical_tokamak function provides a parametric tokamak shaped reactor.
This is characterized by a blanket that only goes around the outboard sides of the plasma.
This reactor allows for a separate vertical and radial build which allows different thickness layers in the blanket.
import paramak
result = paramak.spherical_tokamak(
radial_build=[
(paramak.LayerType.GAP, 10),
(paramak.LayerType.SOLID, 50),
(paramak.LayerType.SOLID, 10),
(paramak.LayerType.GAP, 50),
(paramak.LayerType.PLASMA, 300),
(paramak.LayerType.GAP, 60),
(paramak.LayerType.SOLID, 10),
(paramak.LayerType.SOLID, 60),
(paramak.LayerType.SOLID, 10),
],
vertical_build=[
(paramak.LayerType.SOLID, 15),
(paramak.LayerType.SOLID, 120),
(paramak.LayerType.SOLID, 10),
(paramak.LayerType.GAP, 50),
(paramak.LayerType.PLASMA, 700),
(paramak.LayerType.GAP, 60),
(paramak.LayerType.SOLID, 10),
(paramak.LayerType.SOLID, 30),
(paramak.LayerType.SOLID, 15),
],
rotation_angle=180,
triangularity=0.55,
)
Spherical tokamak from plasma#
The spherical_tokamak_from_plasma function provides a parametric tokamak shaped reactor.
This reactor requires minimal arguments to create as it keeps the vertical build of the blanket layers the same thickness as the radial build.
import paramak
result = paramak.spherical_tokamak_from_plasma(
radial_build=[
(paramak.LayerType.GAP, 10),
(paramak.LayerType.SOLID, 60),
(paramak.LayerType.SOLID, 20),
(paramak.LayerType.GAP, 60),
(paramak.LayerType.PLASMA, 300),
(paramak.LayerType.GAP, 60),
(paramak.LayerType.SOLID, 20),
(paramak.LayerType.SOLID, 120),
(paramak.LayerType.SOLID, 10),
],
elongation=2,
triangularity=0.55,
rotation_angle=90,
)
Spherical tokamak with divertor#
Reactors support adding additional extra intersect shapes that can be used as a divertor.
This example adds a divertor to a spherical_tokamak_from_plasma reactor.
import paramak
from cadquery import Workplane
# makes a rectangle that overlaps the lower blanket under the plasma
# the intersection of this and the layers will form the lower divertor
points = [(200, -700), (200, 0), (300, 0), (300, -700)]
divertor_lower = Workplane('XZ', origin=(0,0,0)).polyline(points).close().revolve(180)
result = paramak.spherical_tokamak_from_plasma(
radial_build=[
(paramak.LayerType.GAP, 10),
(paramak.LayerType.SOLID, 50),
(paramak.LayerType.SOLID, 15),
(paramak.LayerType.GAP, 50),
(paramak.LayerType.PLASMA, 300),
(paramak.LayerType.GAP, 60),
(paramak.LayerType.SOLID, 15),
(paramak.LayerType.SOLID, 60),
(paramak.LayerType.SOLID, 10),
],
elongation=2,
triangularity=0.55,
rotation_angle=180,
extra_intersect_shapes=[divertor_lower]
)
Spherical tokamak with custom divertor#
The revolved_shape function builds a solid by revolving a custom 2D (R, Z, connection) profile. Here straight segments make a small V-shaped divertor plate.
This example adds the revolved shape directly to the reactor assembly with
assembly.add, rather than passing it toextra_intersect_shapes. The plate therefore keeps its full shape and can sit anywhere inside the vessel, outside the blanket envelope — it is not clipped to the blanket.For the alternative approach, where the revolved shape is intersected with the blanket so the divertor is confined to the blanket envelope, see the Tokamak with custom divertor example.
import cadquery as cq
import paramak
# small V-shaped divertor plate from straight segments, sitting in the
# lower cavity between the plasma and the lower blanket
points = [
(160, -312, "straight"),
(220, -336, "straight"),
(280, -312, "straight"),
(280, -330, "straight"),
(220, -354, "straight"),
(160, -330, "straight"),
]
divertor = paramak.revolved_shape(points=points, rotation_angle=180, plane="XZ")
result = paramak.spherical_tokamak_from_plasma(
radial_build=[
(paramak.LayerType.GAP, 10),
(paramak.LayerType.SOLID, 50),
(paramak.LayerType.SOLID, 15),
(paramak.LayerType.GAP, 50),
(paramak.LayerType.PLASMA, 300),
(paramak.LayerType.GAP, 60),
(paramak.LayerType.SOLID, 15),
(paramak.LayerType.SOLID, 60),
(paramak.LayerType.SOLID, 10),
],
elongation=2,
triangularity=0.55,
rotation_angle=180,
)
# add the divertor plate directly to the assembly so it is not clipped to the blanket
result.add(divertor, name="divertor", color=cq.Color("red"))
Spherical tokamak with poloidal field coils#
All reactors support adding a sequence of CadQuery shapes (e.g. workplanes) to the reactor using the extra_cut_shapes argument.
This example adds PF coils to a spherical_tokamak_from_plasma reactor but any other reactor would also work.
import paramak
extra_cut_shapes = []
for case_thickness, height, width, center_point in zip(
[10, 15, 15, 10], [20, 50, 50, 20], [20, 50, 50, 20],
[(500, 300), (560, 100), (560, -100), (500, -300)]
):
extra_cut_shapes.append(
paramak.poloidal_field_coil(
height=height, width=width, center_point=center_point, rotation_angle=270
)
)
extra_cut_shapes.append(
paramak.poloidal_field_coil_case(
coil_height=height,
coil_width=width,
casing_thickness=case_thickness,
rotation_angle=270,
center_point=center_point,
)
)
result = paramak.spherical_tokamak_from_plasma(
radial_build=[
(paramak.LayerType.GAP, 10),
(paramak.LayerType.SOLID, 50),
(paramak.LayerType.SOLID, 15),
(paramak.LayerType.GAP, 50),
(paramak.LayerType.PLASMA, 300),
(paramak.LayerType.GAP, 60),
(paramak.LayerType.SOLID, 15),
(paramak.LayerType.SOLID, 60),
(paramak.LayerType.SOLID, 10),
],
elongation=2,
triangularity=0.55,
rotation_angle=270,
extra_cut_shapes=extra_cut_shapes,
)
Spherical tokamak with toroidal field coils#
In a similar way to adding poloidal field coils one can also add toroidal field coils by making use of the extra_cut_shapes argument.
All reactors support adding a sequence of CadQuery shapes (e.g. workplanes) to the reactor using the extra_cut_shapes argument.
This example adds TF coils to a spherical_tokamak_from_plasma reactor but any other reactor would also work.
Also these are rectangle shaped TF coils but other shapes are also available.
import paramak
tf_style_1 = paramak.toroidal_field_coil_rectangle(
horizontal_start_point = (10, 520),
vertical_mid_point = (600, 0),
thickness = 50,
distance = 40,
rotation_angle = 180,
with_inner_leg = True,
azimuthal_placement_angles = [0, 30, 60, 90, 120, 150, 180],
)
result1 = paramak.spherical_tokamak_from_plasma(
radial_build=[
(paramak.LayerType.GAP, 70),
(paramak.LayerType.SOLID, 10),
(paramak.LayerType.SOLID, 10),
(paramak.LayerType.GAP, 50),
(paramak.LayerType.PLASMA, 300),
(paramak.LayerType.GAP, 60),
(paramak.LayerType.SOLID, 10),
(paramak.LayerType.SOLID, 60),
(paramak.LayerType.SOLID, 10),
],
elongation=2.5,
rotation_angle=180,
triangularity=0.55,
extra_cut_shapes=[tf_style_1]
)
tf_style_2 = paramak.toroidal_field_coil_princeton_d(
r1=5,
r2=610,
azimuthal_placement_angles = [0, 30, 60, 90, 120, 150, 180],
rotation_angle = 180,
thickness = 50,
distance = 40
)
result2 = paramak.spherical_tokamak_from_plasma(
radial_build=[
(paramak.LayerType.GAP, 70),
(paramak.LayerType.SOLID, 10),
(paramak.LayerType.SOLID, 10),
(paramak.LayerType.GAP, 50),
(paramak.LayerType.PLASMA, 300),
(paramak.LayerType.GAP, 60),
(paramak.LayerType.SOLID, 10),
(paramak.LayerType.SOLID, 60),
(paramak.LayerType.SOLID, 10),
],
elongation=2.5,
rotation_angle=180,
triangularity=0.55,
extra_cut_shapes=[tf_style_2]
)
import cadquery as cq
result = cq.Assembly()
result.add(result1, name="rectangular_tf", loc=cq.Location(cq.Vector(700, 0, 0)))
result.add(result2, name="princeton_d_tf", loc=cq.Location(cq.Vector(-700, 0, 0)))
Spherical tokamak with negative triangularity#
The triangularity argument can be set to a negative value to make a plasma with a negative triangularity.
This example makes a spherical tokamak with a negative triangularity but this would work on any reactor.
import paramak
result = paramak.spherical_tokamak(
radial_build=[
(paramak.LayerType.GAP, 10),
(paramak.LayerType.SOLID, 50),
(paramak.LayerType.SOLID, 15),
(paramak.LayerType.GAP, 50),
(paramak.LayerType.PLASMA, 300),
(paramak.LayerType.GAP, 60),
(paramak.LayerType.SOLID, 40),
(paramak.LayerType.SOLID, 60),
(paramak.LayerType.SOLID, 10),
],
vertical_build=[
(paramak.LayerType.SOLID, 15),
(paramak.LayerType.SOLID, 80),
(paramak.LayerType.SOLID, 10),
(paramak.LayerType.GAP, 50),
(paramak.LayerType.PLASMA, 700),
(paramak.LayerType.GAP, 60),
(paramak.LayerType.SOLID, 10),
(paramak.LayerType.SOLID, 40),
(paramak.LayerType.SOLID, 15),
],
rotation_angle=180,
triangularity=-0.55,
)
Spherical tokamak with poloidal segments#
The poloidal_build argument splits the layers after the plasma into poloidal segments, for example first wall tiles or blanket modules separated by gaps.
poloidal_build has one entry per radial_build entry after the plasma, ordered from the plasma outwards. Entries are None for layers that are not segmented, otherwise a list of segments in the same format as radial_build entries: (paramak.LayerType.SOLID, arc_length, name) for a solid segment (the name is optional) or (paramak.LayerType.GAP, arc_length) for a gap.
Arc lengths are measured along the plasma facing surface for every layer. This surface starts where the layer meets the centre column at the bottom, runs along the bottom, up the outboard side and along the top back to the centre column. Each entry must sum to the arc length returned by paramak.spherical_poloidal_arc_length.
Cuts are vertical along the top and bottom and follow the normal to the plasma surface on the outboard side, so layers given the same segments line up.
This example splits the first wall and blanket into the same modules.
import paramak
radial_build = [
(paramak.LayerType.GAP, 10),
(paramak.LayerType.SOLID, 50),
(paramak.LayerType.SOLID, 15),
(paramak.LayerType.GAP, 50),
(paramak.LayerType.PLASMA, 300),
(paramak.LayerType.GAP, 60),
(paramak.LayerType.SOLID, 15), # first wall
(paramak.LayerType.SOLID, 60), # blanket
(paramak.LayerType.SOLID, 10), # rear wall
]
# arc length that the segments of each layer must sum to
arc_length = paramak.spherical_poloidal_arc_length(radial_build, elongation=2.0, triangularity=0.55)
number_of_modules = 8
module_gap = 15 # gap between neighbouring modules
module_length = (arc_length - number_of_modules * module_gap) / number_of_modules
modules = [(paramak.LayerType.SOLID, module_length, "module"), (paramak.LayerType.GAP, module_gap)] * number_of_modules
result = paramak.spherical_tokamak_from_plasma(
radial_build=radial_build,
poloidal_build=[
None, # gap after the plasma
modules, # first wall
modules, # blanket, the same modules so the gaps line up
None, # rear wall
],
elongation=2.0,
triangularity=0.55,
rotation_angle=180,
)
Spherical tokamak with toroidal sectors#
The toroidal_build argument splits layers into toroidal sectors, for example sectors separated by assembly gaps.
toroidal_build has one entry per radial_build entry after the plasma, ordered from the plasma outwards, like poloidal_build. Entries are None for layers that are not segmented, otherwise a list of segments: (paramak.LayerType.SOLID, arc_length, name) for a sector (the name is optional) or (paramak.LayerType.GAP, width) for a gap.
Arc lengths are measured around the plasma facing surface at the outboard midplane, starting at rotation_start_angle (the XZ plane by default), and each entry must sum to the arc length returned by paramak.toroidal_arc_length.
Gaps are slots with parallel sides, so a gap has the same width at every radius.
Sectors are named “<layer name>_<sector name>”. toroidal_build can be combined with poloidal_build, in which case each poloidal segment is split into sectors.
This example splits the first wall and blanket into the same six sectors, so the gaps run straight through them, and leaves the rear wall as a continuous ring.
import paramak
radial_build = [
(paramak.LayerType.GAP, 10),
(paramak.LayerType.SOLID, 50),
(paramak.LayerType.SOLID, 15),
(paramak.LayerType.GAP, 50),
(paramak.LayerType.PLASMA, 300),
(paramak.LayerType.GAP, 60),
(paramak.LayerType.SOLID, 15), # first wall
(paramak.LayerType.SOLID, 60), # blanket
(paramak.LayerType.SOLID, 10), # rear wall
]
rotation_angle = 180
# arc length that the sectors of each layer must sum to
arc_length = paramak.toroidal_arc_length(radial_build, rotation_angle=rotation_angle)
number_of_sectors = 6
sector_gap = 20 # width of the gap between neighbouring sectors
sector_length = (arc_length - number_of_sectors * sector_gap) / number_of_sectors
sectors = [
(paramak.LayerType.SOLID, sector_length, "sector"),
(paramak.LayerType.GAP, sector_gap),
] * number_of_sectors
result = paramak.spherical_tokamak_from_plasma(
radial_build=radial_build,
toroidal_build=[
None, # gap after the plasma
sectors, # first wall
sectors, # blanket
None, # rear wall, not split so it stays a continuous ring
],
elongation=2.0,
triangularity=0.55,
rotation_angle=rotation_angle,
)
Naming spherical tokamak parts#
Every part in the assembly has a name, used when assigning material tags and per-part colors. By default layers are named
layer_1,layer_2… working outwards and the plasma is namedplasma. The name of every part can be listed withmy_reactor.names().There are two ways to give layers meaningful names: add an optional name (a string) as the third element of a
radial_buildlayer tuple, or rename parts after building withrename(old, new).Unlike the tokamak, the layers of a spherical tokamak do not revolve around the plasma: the inboard layers are concentric cylinders (the central column) and the outboard layers are the blanket. Every radial solid layer is therefore its own part and is named directly from its
radial_buildentry. Names are only supported in theradial_build, not thevertical_build.
import paramak
# Option 1 - name the layers in the radial build
my_reactor = paramak.spherical_tokamak_from_plasma(
radial_build=[
(paramak.LayerType.GAP, 10),
(paramak.LayerType.SOLID, 50, "central column"),
(paramak.LayerType.SOLID, 15, "tf coil"),
(paramak.LayerType.GAP, 50),
(paramak.LayerType.PLASMA, 300),
(paramak.LayerType.GAP, 60),
(paramak.LayerType.SOLID, 10, "first wall"),
(paramak.LayerType.SOLID, 30, "blanket"),
],
rotation_angle=180,
)
print(my_reactor.names())
# ['central column', 'tf coil', 'first wall', 'blanket', 'plasma']
import paramak
# Option 2 - rename parts after building the reactor (chainable)
my_reactor = paramak.spherical_tokamak_from_plasma(
radial_build=[
(paramak.LayerType.GAP, 10),
(paramak.LayerType.SOLID, 50),
(paramak.LayerType.SOLID, 15),
(paramak.LayerType.GAP, 50),
(paramak.LayerType.PLASMA, 300),
(paramak.LayerType.GAP, 60),
(paramak.LayerType.SOLID, 10),
(paramak.LayerType.SOLID, 30),
],
rotation_angle=180,
)
my_reactor = (
my_reactor
.rename("layer_1", "central column")
.rename("layer_2", "tf coil")
.rename("layer_3", "first wall")
.rename("layer_4", "blanket")
)
print(my_reactor.names())
# ['central column', 'tf coil', 'first wall', 'blanket', 'plasma']