1253 superconducting busbars

process/power.py

@@ -103,9 +103,10 @@ def pfpwr(self, output: bool):
             albusa[ig] = abs(pfcoil_variables.cptdin[ic]) / 100.0e0
 
             #  Resistance of bussing for circuit (ohm)
-            #  Include 50% enhancement for welds, joints etc, (G. Gorker, ORNL)
             #  pfbusl : bus length for each PF circuit (m)
-            pfbusr[ig] = 1.5e0 * 2.62e-4 * pfbusl / albusa[ig]
+            #  pfbusr[ig] = 1.5e0 * 2.62e-4 * pfbusl / albusa[ig]
+            #  I have removed the fudge factor of 1.5 but included it in the value of rhopfbus
+            pfbusr[ig] = pfcoil_variables.rhopfbus * pfbusl / (albusa[ig] / 10000)
 
             #  Total PF coil resistance (during burn)
             #  pfcoil_variables.ric : maximum current in coil (A)
@@ -2474,14 +2475,9 @@ def tfpwr(self, output: bool):
             abus = tfcoil_variables.cpttf / tfcoil_variables.jbus
 
             # Bus resistance [ohm]
-            # Bus resistivity (tfcoil_variables.rhotfbus) default value : -1.0e0
-            # If this value is chosen, the bus resistivity is the same as the leg one
-            if (
-                abs(tfcoil_variables.rhotfbus + 1.0e0)
-                < numpy.finfo(float(tfcoil_variables.rhotfbus)).eps
-            ):
-                tfcoil_variables.rhotfbus = tfcoil_variables.rhotfleg
-
+            # Bus resistivity (tfcoil_variables.rhotfbus)
+            # Issue #1253: there was a fudge here to set the bus bar resistivity equal
+            # to the TF conductor resistivity. I have removed this.
             tfbusres = tfcoil_variables.rhotfbus * tfcoil_variables.tfbusl / abus
 
             #  Bus mass (kg)
@@ -2712,7 +2708,8 @@ def tfcpwr(self, output: bool, itfka, rmajor, ntfc, vtfskv, ettfmj, rptfc):
         albuswt = 2.7e0 * albusa * tfbusl / 1.0e4
 
         #  Total resistance of TF bus, ohms
-        rtfbus = 2.62e-4 * tfbusl / albusa
+        # rtfbus = 2.62e-4 * tfbusl / albusa
+        rtfbus = tfcoil_variables.rhotfbus * tfbusl / (albusa / 10000)
 
         #  Total voltage drop across TF bus, volts
         vtfbus = 1000.0e0 * itfka * rtfbus

process/pulse.py

@@ -73,7 +73,9 @@ def tohswg(self, output: bool) -> None:
         pfbusl = 8.0e0 * physics_variables.rmajor + 140.0e0
         albusa = abs(pfcoil_variables.cptdin[pfcoil_variables.nohc - 1]) / 100.0e0
 
-        rho = 1.5e0 * 2.62e-4 * pfbusl / albusa
+        # rho = 1.5e0 * 2.62e-4 * pfbusl / albusa
+        #  I have removed the fudge factor of 1.5 but included it in the value of rhopfbus
+        rho = pfcoil_variables.rhopfbus * pfbusl / (albusa / 10000)
 
         #  Central Solenoid power source emf (volts)
 

source/fortran/input.f90

@@ -296,7 +296,7 @@ subroutine parse_input_file(in_file,out_file,show_changes)
       coreradiationfraction, fimp
     use numerics, only: factor, boundl, minmax, neqns, nvar, epsfcn, ixc, &
       epsvmc, ftol, ipnvars, ioptimz, nineqns, ipeqns, boundu, icc, ipnfoms, name_xc
-    use pfcoil_variables, only: rjconpf, zref, fcuohsu, oh_steel_frac, vf, &
+    use pfcoil_variables, only: rhopfbus, rjconpf, zref, fcuohsu, oh_steel_frac, vf, &
       coheof, sigpfcalw, alstroh, ipfres, fcupfsu, fvssu, etapsu, i_cs_stress, &
       fbmaxcs, ngc, rpf2, fcohbop, ohhghf, vfohc, isumatoh, ngrpmx, ngc2, rpf1, &
       ngrp, isumatpf, nfxfh, alfapf, routr, sigpfcf, pfclres, bmaxcs_lim, &
@@ -1814,6 +1814,9 @@ subroutine parse_input_file(in_file,out_file,show_changes)
 
        !  PF coil settings
 
+       case ('rhopfbus')
+          call parse_real_variable('rhopfbus', rhopfbus, 0.0D0, 1.0D-5, &
+               'CS and PF coil bus (feeders) resistivity (ohm-m)')
        case ('bmaxcs_lim')
          call parse_real_variable('bmaxcs_lim', bmaxcs_lim, 0.01D0, 100.0D0, &
                'Maximum allowed peak field on central solenoid')

source/fortran/pfcoil_variables.f90

@@ -223,6 +223,10 @@ module pfcoil_variables
   real(dp) :: pfclres
   !! PF coil resistivity (if ipfres=1) (Ohm-m)
 
+  real(dp) :: rhopfbus
+  !! Resistivity of CS and PF coil bus bars (irrespective of
+  !! whether the coils themselves are superconducting or resistive) (Ohm-m)
+
   real(dp) :: pfmmax
   !! mass of heaviest PF coil (tonnes)
 
@@ -450,6 +454,7 @@ subroutine init_pfcoil_variables
     pf_current_safety_factor = 1.0D0
     pfcaseth = 0.0D0
     pfclres = 2.5D-8
+    rhopfbus = 3.93D-8
     pfmmax = 0.0D0
     pfrmax = 0.0D0
     pfwpmw = 0.0D0

source/fortran/tfcoil_variables.f90

@@ -955,7 +955,7 @@ subroutine init_tfcoil_variables
     tflegmw = 0.0D0
     rhocp = 0.0D0
     rhotfleg = 0.0D0
-    rhotfbus = -1.0D0 ! 2.5D-8
+    rhotfbus = 2.62D-8    !-1.0D0 ! 2.5D-8
     frhocp = 1.0D0
     frholeg = 1.0D0
     rho_tf_joints = 2.5D-10

tests/integration/data/test_solver.conf

@@ -2,7 +2,7 @@
 *
 
 * No iterations
-NITER = 10
+NITER = 1
 
 * sets flag of same name in IN.DAT: 
 *     None - keeps original value