## Abstract

In reactor physics courses and standard text books the four factor formula and two group theory is often used to demonstrate to the students the physical processes in the chain reaction of nuclear reactors. When compared with measurements, in particular of light water reactors, the agreement between these simple recipes and measurements is not very good. In this report it has been investigated whether it is possible to introduce some relative simple modifications to such a recipe in order to obtain better agreement between theory and measurements. The modifications considered were: (1) The introduction of the Westcott rs-term. (2) An improved model for the fast fission factor {epsilon}. (3) An improved model for the slowing-down length L{sub s}. (4) The introduction of a Dancoff correction in the calculation of the resonance escape probability p. (5) An improved model for the neutron temperature of the fuel. With these modifications the agreement between measurements and calculations of light water, slightly enriched uranium metal rod lattices was greatly improved. However, it is necessary to consider more, different lattices in order to evaluate the general validity of these apparent recipe improvements. (au).

## Citation Formats

Oelgaard, P L.
Improvements in a four factor formula recipe for lattice calculations.
Denmark: N. p.,
1994.
Web.

Oelgaard, P L.
Improvements in a four factor formula recipe for lattice calculations.
Denmark.

Oelgaard, P L.
1994.
"Improvements in a four factor formula recipe for lattice calculations."
Denmark.

@misc{etde_10114783,

title = {Improvements in a four factor formula recipe for lattice calculations}

author = {Oelgaard, P L}

abstractNote = {In reactor physics courses and standard text books the four factor formula and two group theory is often used to demonstrate to the students the physical processes in the chain reaction of nuclear reactors. When compared with measurements, in particular of light water reactors, the agreement between these simple recipes and measurements is not very good. In this report it has been investigated whether it is possible to introduce some relative simple modifications to such a recipe in order to obtain better agreement between theory and measurements. The modifications considered were: (1) The introduction of the Westcott rs-term. (2) An improved model for the fast fission factor {epsilon}. (3) An improved model for the slowing-down length L{sub s}. (4) The introduction of a Dancoff correction in the calculation of the resonance escape probability p. (5) An improved model for the neutron temperature of the fuel. With these modifications the agreement between measurements and calculations of light water, slightly enriched uranium metal rod lattices was greatly improved. However, it is necessary to consider more, different lattices in order to evaluate the general validity of these apparent recipe improvements. (au).}

place = {Denmark}

year = {1994}

month = {Dec}

}

title = {Improvements in a four factor formula recipe for lattice calculations}

author = {Oelgaard, P L}

abstractNote = {In reactor physics courses and standard text books the four factor formula and two group theory is often used to demonstrate to the students the physical processes in the chain reaction of nuclear reactors. When compared with measurements, in particular of light water reactors, the agreement between these simple recipes and measurements is not very good. In this report it has been investigated whether it is possible to introduce some relative simple modifications to such a recipe in order to obtain better agreement between theory and measurements. The modifications considered were: (1) The introduction of the Westcott rs-term. (2) An improved model for the fast fission factor {epsilon}. (3) An improved model for the slowing-down length L{sub s}. (4) The introduction of a Dancoff correction in the calculation of the resonance escape probability p. (5) An improved model for the neutron temperature of the fuel. With these modifications the agreement between measurements and calculations of light water, slightly enriched uranium metal rod lattices was greatly improved. However, it is necessary to consider more, different lattices in order to evaluate the general validity of these apparent recipe improvements. (au).}

place = {Denmark}

year = {1994}

month = {Dec}

}