class openmc.deplete.CECMIntegrator(operator, timesteps, power=None, power_density=None)[source]

Deplete using the CE/CM algorithm.

Implements the second order CE/CM predictor-corrector algorithm.

“CE/CM” stands for constant extrapolation on predictor and constant midpoint on corrector. This algorithm is mathematically defined as:

\[\begin{aligned} y' &= A(y, t) y(t) \\ A_p &= A(y_n, t_n) \\ y_m &= \text{expm}(A_p h/2) y_n \\ A_c &= A(y_m, t_n + h/2) \\ y_{n+1} &= \text{expm}(A_c h) y_n \end{aligned} \]
  • operator (openmc.deplete.TransportOperator) – Operator to perform transport simulations
  • timesteps (iterable of float) – Array of timesteps in units of [s]. Note that values are not cumulative.
  • power (float or iterable of float, optional) – Power of the reactor in [W]. A single value indicates that the power is constant over all timesteps. An iterable indicates potentially different power levels for each timestep. For a 2D problem, the power can be given in [W/cm] as long as the “volume” assigned to a depletion material is actually an area in [cm^2]. Either power or power_density must be specified.
  • power_density (float or iterable of float, optional) – Power density of the reactor in [W/gHM]. It is multiplied by initial heavy metal inventory to get total power if power is not speficied.
  • operator (openmc.deplete.TransportOperator) – Operator to perform transport simulations
  • chain (openmc.deplete.Chain) – Depletion chain
  • timesteps (iterable of float) – Size of each depletion interval in [s]
  • power (iterable of float) – Power of the reactor in [W] for each interval in timesteps
__call__(conc, rates, dt, power, _i=None)[source]

Integrate using CE/CM

  • conc (numpy.ndarray) – Initial concentrations for all nuclides in [atom]
  • rates (openmc.deplete.ReactionRates) – Reaction rates from operator
  • dt (float) – Time in [s] for the entire depletion interval
  • power (float) – Power of the system [W]
  • _i (int, optional) – Current iteration count. Not used

  • proc_time (float) – Time spent in CRAM routines for all materials in [s]
  • conc_list (list of numpy.ndarray) – Concentrations at each of the intermediate points with the final concentration as the last element
  • op_results (list of openmc.deplete.OperatorResult) – Eigenvalue and reaction rates from transport simulations


Return pairs of time steps in [s] and powers in [W]


Return integer number of depletion intervals


Perform the entire depletion process across all steps