Masters Theses

Keywords and Phrases

Monte Carlo N-Particle (MCNP); Subcritical assembly


"The Missouri University of Science and Technology Subcritical Assembly (S&TSub) was brought back into service and upgraded with a new neutron detection system and internet access. Before the upgrade neutron counting was only possible in one location. Using a movable detection system housed in acrylic tubes measurements can now be taken in any empty fuel location and at any height within the tube, making three dimensional flux mapping a possibility. By connecting the new detection system to a Canberra Lynx Digital Signal Analyzer, remote users can have limited data collecting capabilities. To further enhance the potential of the facility, an MCNP model of the S&TSub was created, and validated by comparing its simulated predictions to experiments conducted at the facility. An approach to criticality experiment using the 1/M approximation showed that the MCNP model accurately predicts keff if the detectors are place between 27 cm and 36 cm from the neutron source. The results of an axial flux measurement experiment differed from the MCNP simulated results by an average of 12%. Finally, the validated MCNP model was used to show the effect of removing the facility's fixed detector tube and redistributing its fuel. MCNP simulation predicts that the new configuration would increase the multiplication factor from 0.73481ł8.080E-05 to 0.76844ł4.610E-05 and increase the flux magnitude by 36%"--Abstract, page iv.


Usman, Shoaib

Committee Member(s)

Lee, Hyoung-Koo
Kumar, A. S. (Arvind S.)
Castaño, Carlos H.


Nuclear Engineering and Radiation Science

Degree Name

M.S. in Nuclear Engineering


Missouri University of Science and Technology

Publication Date

Summer 2011


x, 34 pages

Note about bibliography

Includes bibliographical references.

Geographic Coverage

Rolla (Mo.)


© 2011 Lucas Powelson Tucker, All rights reserved.

Document Type

Thesis - Open Access

File Type




Subject Headings

Missouri University of Science and Technology
Neutron counters
Nuclear facilities -- Missouri -- Rolla

Thesis Number

T 9871

Print OCLC #


Electronic OCLC #