constraint_eqn_023 Subroutine

   subroutine constraint_eqn_023(tmp_cc, tmp_con, tmp_err, tmp_symbol, tmp_units)
      !! Equation for conducting shell radius / rminor upper limit
      !! author: P B Lloyd, CCFE, Culham Science Centre
      !! args : output structure : residual error; constraint value;
      !! residual error in physical units; output string; units string
      !! Equation for conducting shell radius / rminor upper limit
      !! #=# physics
      !! #=#=# fcwr, cwrmax
      !! and hence also optional here.
      !! Logic change during pre-factoring: err, symbol, units will be assigned only if present.
      !! rminor : input real : plasma minor radius (m)
      !! scraplo : input real : gap between plasma and first wall, outboard side (m)
      !! fwoth : input real : outboard first wall thickness, initial estimate (m)
      !! blnkoth : input real : outboard blanket thickness (m)
      !! fcwr : input real : f-value for conducting wall radius / rminor limit
      !! cwrmax : input real : maximum ratio of conducting wall distance to plasma minor radius for vertical stability
      use physics_variables, only: rminor, cwrmax
      use build_variables, only: scraplo, fwoth, blnkoth
      use constraint_variables, only: fcwr
      implicit none
            real(dp), intent(out) :: tmp_cc
      real(dp), intent(out) :: tmp_con
      real(dp), intent(out) :: tmp_err
      character(len=1), intent(out) :: tmp_symbol
      character(len=10), intent(out) :: tmp_units
      ! rcw : local real : conducting shell radius (m)
      real(dp) :: rcw

      rcw = rminor + scraplo + fwoth + blnkoth
      tmp_cc =  1.0D0 - fcwr * cwrmax*rminor / rcw
      tmp_con = cwrmax*rminor * (1.0D0 - tmp_cc)
      tmp_err = rcw * tmp_cc
      tmp_symbol = '<'
      tmp_units = 'm'

   end subroutine constraint_eqn_023