Development of an Empirical Correlation for the Manganese Sulfate Bath Neutron Absorption in Manganese Fraction Using the Monte Carlo N-Particle Code
Open Access
- Author:
- Bucks, Scout
- Area of Honors:
- Mechanical Engineering
- Degree:
- Bachelor of Science
- Document Type:
- Thesis
- Thesis Supervisors:
- Marek Flaska, Thesis Supervisor
Margaret Louise Byron, Thesis Honors Advisor
Guhaprasanna Manogharan, Faculty Reader - Keywords:
- Manganese Bath
MCNP
252-Cf
241-Am-Be
249-Pu-Be
Manganese Absorption Fraction - Abstract:
- The manganese (Mn) sulfate (SO4) bath is the primary tool for making high-precision measurements of isotopic neutron source emission rates. When a neutron source is submerged in aqueous MnSO4 solution, neutrons from the source are absorbed in Mn, thereby producing γ-radiation. These photons are then measured to accurately calculate the neutron source strength. A key parameter for these measurement systems is the fraction of neutrons leaving the source that are absorbed in Mn as opposed to other Mn bath components or leaking from the Mn bath. This manganese absorption fraction is usually calculated with Monte Carlo methods. To support the creation of a Mn bath facility at The Pennsylvania State University, simulations of a generalized manganese bath were performed using the Monte Carlo N-Particle (MCNP) code. The goal was to generate empirical correlations for calculating the manganese absorption fraction for different spherical bath radii, solution densities, and neutron source types. The expected leakage from Mn baths was also explored. Extensive work went into transforming physical phenomena into their simulated equivalents, and the resulting MCNP framework was validated against three simulations published in the literature. In total, 336 simulations were performed using one million neutrons for each run to provide acceptable statistical variances. Am-Be, Cf, and Pu-Be sources were studied for bath radii between 10 and 75 cm and for solution densities between 1.05 and 1.40 g/cm^3 . An empirical correlation in terms of radius and density was created for each source type. These correlations matched the simulation data to within 2% for baths with a bath radius of 20 cm or larger. These correlations and the MCNP tools developed for this project will aid in an actual design of a new manganese bath facility.