# Optimization of Depletion Modeling and Simulation for the High Flux Isotope Reactor

## Abstract

Monte Carlo based depletion tools used for the high-fidelity modeling and simulation of the High Flux Isotope Reactor (HFIR) come at a great computational cost; finding sufficient approximations is necessary to make the use of these tools feasible. The optimization of the neutronics and depletion model for the HFIR is based on two factors: (i) the explicit representation of the involute fuel plates with sets of polyhedra and (ii) the treatment of depletion mixtures and control element position during depletion calculations. A very fine representation (i.e., more polyhedra in the involute plate approximation) does not significantly improve simulation accuracy. The recommended representation closely represents the physical plates and ensures sufficient fidelity in regions with high flux gradients. Including the fissile targets in the central flux trap of the reactor as depletion mixtures has the greatest effect on the calculated cycle length, while localized effects (e.g., the burnup of specific isotopes or the power distribution evolution over the cycle) are more noticeable consequences of including a critical control element search or depleting burnable absorbers outside the fuel region.

- Authors:

- ORNL

- Publication Date:

- Research Org.:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). High Flux Isotope Reactor (HFIR)

- Sponsoring Org.:
- USDOE National Nuclear Security Administration (NNSA)

- OSTI Identifier:
- 1185801

- DOE Contract Number:
- DE-AC05-00OR22725

- Resource Type:
- Conference

- Resource Relation:
- Conference: Joint International Conference Mathematics and Computation (M&C), Supercomputing in Nuclear Applications (SNA) and the Monte Carlo (MC) Method, Nashville, TN, USA, 20150419, 20150419

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 22 GENERAL STUDIES OF NUCLEAR REACTORS; HFIR; Monte Carlo; Depletion

### Citation Formats

```
Betzler, Benjamin R, Ade, Brian J, Chandler, David, Ilas, Germina, and Sunny, Eva E.
```*Optimization of Depletion Modeling and Simulation for the High Flux Isotope Reactor*. United States: N. p., 2015.
Web.

```
Betzler, Benjamin R, Ade, Brian J, Chandler, David, Ilas, Germina, & Sunny, Eva E.
```*Optimization of Depletion Modeling and Simulation for the High Flux Isotope Reactor*. United States.

```
Betzler, Benjamin R, Ade, Brian J, Chandler, David, Ilas, Germina, and Sunny, Eva E. Thu .
"Optimization of Depletion Modeling and Simulation for the High Flux Isotope Reactor". United States.
doi:.
```

```
@article{osti_1185801,
```

title = {Optimization of Depletion Modeling and Simulation for the High Flux Isotope Reactor},

author = {Betzler, Benjamin R and Ade, Brian J and Chandler, David and Ilas, Germina and Sunny, Eva E},

abstractNote = {Monte Carlo based depletion tools used for the high-fidelity modeling and simulation of the High Flux Isotope Reactor (HFIR) come at a great computational cost; finding sufficient approximations is necessary to make the use of these tools feasible. The optimization of the neutronics and depletion model for the HFIR is based on two factors: (i) the explicit representation of the involute fuel plates with sets of polyhedra and (ii) the treatment of depletion mixtures and control element position during depletion calculations. A very fine representation (i.e., more polyhedra in the involute plate approximation) does not significantly improve simulation accuracy. The recommended representation closely represents the physical plates and ensures sufficient fidelity in regions with high flux gradients. Including the fissile targets in the central flux trap of the reactor as depletion mixtures has the greatest effect on the calculated cycle length, while localized effects (e.g., the burnup of specific isotopes or the power distribution evolution over the cycle) are more noticeable consequences of including a critical control element search or depleting burnable absorbers outside the fuel region.},

doi = {},

journal = {},

number = ,

volume = ,

place = {United States},

year = {Thu Jan 01 00:00:00 EST 2015},

month = {Thu Jan 01 00:00:00 EST 2015}

}