Doctoral Dissertations

Keywords and Phrases

Activation Method; Beam-Port design; Neutron Beam-port; Reactor flux characterization; SAND-II; Under-water beam-port


“The beam-port is a cardinal facility at research reactors necessary for dry irradiation, testing and measurement experiments. The Missouri University of Science and Technology Reactor (MSTR) is one such reactor with a beam-port. Installation of additional beam-port in such reactor facilities can be prohibitive. A novel remedy to this is an underwater beam-port for pool-type reactors. The design and characterization of a conceptual underwater multi-spectral beam-port for neutron and gamma fluxes were completed for the MSTR. The neutron spectra from the MSTR were simulated using the Monte Carlo N-particle (MCNP). The determined neutron spectra were experimentally validated using SAND-II. The underwater beam-port system was designed to be portable so that it could be moved in and out of the reactor pool. Filters and collimators were used to modify the neutron beams for thermal and fast neutron densities as well as gamma energy spectra at the target location. In its most thermal neutron configuration, the beam-port delivered 1.43 × 109 n cm-2 s-1 to the target with 91.7% of the flux having energies no greater than 0.55 eV. The hardest spectrum achievable in its fast neutron configuration was 4.95 × 109 n cm-2 s-1 with 51.8% of the flux having energies greater than 0.1 MeV. The beam-port was able to deliver gamma flux of 3.19×1010 photons/cm2s to the target. A predictive algorithm was developed in MATLAB so that: 1.) beam flux quality could be determined given collimator and filter dimensions and 2.) Collimator and filter dimension could be determined given desired flux qualities. For both scenarios, the maximum prediction errors were 19% and 8.5%, respectively. The algorithm reduced time required for one simulation to 0.007 seconds from 179 minutes when using MCNP"--Abstract, page iii.


Alajo, Ayodeji Babatunde

Committee Member(s)

Lee, Hyoung-Koo
Castano Giraldo, Carlos Henry
Liu, Xin (Mining & Nuclear Engr)
Elrod, Cassandra C., 1979-


Nuclear Engineering and Radiation Science

Degree Name

Ph. D. in Nuclear Engineering


The author would like to thank the King Abdulaziz City for Science and Technology for sponsoring his PhD studies


Missouri University of Science and Technology

Publication Date

Fall 2018


xiv, 102 pages

Note about bibliography

Includes bibliographic references (pages 98-101).


© 2018 Meshari Mesfer Alqahtani, All rights reserved.

Document Type

Dissertation - Open Access

File Type




Thesis Number

T 11997

Electronic OCLC #