# How Accurately can we Calculate Thermal Systems?

## Abstract

I would like to determine how accurately a variety of neutron transport code packages (code and cross section libraries) can calculate simple integral parameters, such as K{sub eff}, for systems that are sensitive to thermal neutron scattering. Since we will only consider theoretical systems, we cannot really determine absolute accuracy compared to any real system. Therefore rather than accuracy, it would be more precise to say that I would like to determine the spread in answers that we obtain from a variety of code packages. This spread should serve as an excellent indicator of how accurately we can really model and calculate such systems today. Hopefully, eventually this will lead to improvements in both our codes and the thermal scattering models that they use in the future. In order to accomplish this I propose a number of extremely simple systems that involve thermal neutron scattering that can be easily modeled and calculated by a variety of neutron transport codes. These are theoretical systems designed to emphasize the effects of thermal scattering, since that is what we are interested in studying. I have attempted to keep these systems very simple, and yet at the same time they include most, if notmore »

- Authors:

- Publication Date:

- Research Org.:
- Lawrence Livermore National Lab., Livermore, CA (US)

- Sponsoring Org.:
- US Department of Energy (US)

- OSTI Identifier:
- 15009834

- Report Number(s):
- UCRL-TR-203892

TRN: US0406642

- DOE Contract Number:
- W-7405-ENG-48

- Resource Type:
- Technical Report

- Resource Relation:
- Other Information: PBD: 20 Apr 2004

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; 22 GENERAL STUDIES OF NUCLEAR REACTORS; ACCURACY; CROSS SECTIONS; NEUTRON TRANSPORT; SCATTERING; THERMAL NEUTRONS; THERMAL REACTORS; URANIUM

### Citation Formats

```
Cullen, D, Blomquist, R N, Dean, C, Heinrichs, D, Kalugin, M A, Lee, M, Lee, Y, MacFarlan, R, Nagaya, Y, and Trkov, A.
```*How Accurately can we Calculate Thermal Systems?*. United States: N. p., 2004.
Web. doi:10.2172/15009834.

```
Cullen, D, Blomquist, R N, Dean, C, Heinrichs, D, Kalugin, M A, Lee, M, Lee, Y, MacFarlan, R, Nagaya, Y, & Trkov, A.
```*How Accurately can we Calculate Thermal Systems?*. United States. doi:10.2172/15009834.

```
Cullen, D, Blomquist, R N, Dean, C, Heinrichs, D, Kalugin, M A, Lee, M, Lee, Y, MacFarlan, R, Nagaya, Y, and Trkov, A. Tue .
"How Accurately can we Calculate Thermal Systems?". United States.
doi:10.2172/15009834. https://www.osti.gov/servlets/purl/15009834.
```

```
@article{osti_15009834,
```

title = {How Accurately can we Calculate Thermal Systems?},

author = {Cullen, D and Blomquist, R N and Dean, C and Heinrichs, D and Kalugin, M A and Lee, M and Lee, Y and MacFarlan, R and Nagaya, Y and Trkov, A},

abstractNote = {I would like to determine how accurately a variety of neutron transport code packages (code and cross section libraries) can calculate simple integral parameters, such as K{sub eff}, for systems that are sensitive to thermal neutron scattering. Since we will only consider theoretical systems, we cannot really determine absolute accuracy compared to any real system. Therefore rather than accuracy, it would be more precise to say that I would like to determine the spread in answers that we obtain from a variety of code packages. This spread should serve as an excellent indicator of how accurately we can really model and calculate such systems today. Hopefully, eventually this will lead to improvements in both our codes and the thermal scattering models that they use in the future. In order to accomplish this I propose a number of extremely simple systems that involve thermal neutron scattering that can be easily modeled and calculated by a variety of neutron transport codes. These are theoretical systems designed to emphasize the effects of thermal scattering, since that is what we are interested in studying. I have attempted to keep these systems very simple, and yet at the same time they include most, if not all, of the important thermal scattering effects encountered in a large, water-moderated, uranium fueled thermal system, i.e., our typical thermal reactors.},

doi = {10.2172/15009834},

journal = {},

number = ,

volume = ,

place = {United States},

year = {Tue Apr 20 00:00:00 EDT 2004},

month = {Tue Apr 20 00:00:00 EDT 2004}

}