Masters Theses

Keywords and Phrases

252Cf; Fresh MTR fuel; MCNP benchmarking; Neutron coincidence counting; Nondestructive assay; Time correlated induced fission


"The effective application of international safeguards to research reactors requires verification of spent fuel as well as fresh fuel. To accomplish this goal various nondestructive and destructive assay techniques have been developed in the US and around the world. The Advanced Experimental Fuel Counter (AEFC) is a nondestructive assay (NDA) system developed at Los Alamos National Laboratory (LANL) combining both neutron and gamma measurement capabilities. Since spent fuel assemblies are stored in water, the system was designed to be watertight to facilitate underwater measurements by inspectors. The AEFC is comprised of six 3He detectors as well as a shielded and collimated ion chamber. The 3He detectors are used for active and passive neutron coincidence counting while the ion chamber is used for gross gamma counting. In the past, most of the active interrogation systems along with the AEFC were calibrated by AmLi neutron source. In this study, experiments were performed to calibrate the AEFC instrument and compare use of the 252Cf spontaneous fission source and the AmLi (α,n) neutron emission source. MCNP simulations were carried out to benchmark experiments. This thesis analyzes time correlated induced fission (TCIF) from fresh MTR fuel assemblies due to 252Cf and AmLi active interrogation sources. Benchmarking showed MCNP singles and doubles count rates agree with experimental singles and doubles within 5% and 4% respectively in the case of full assembly. After normalizing 252Cf to the AmLi source strength, AmLi resulted 1.228 times more IF singles rate, while 252Cf resulted 1.176 times more IF doubles rate. This indicates the boost in the doubles rate with 252Cf source is due to the TCIF effect"--Abstract, page iii.


Usman, Shoaib

Committee Member(s)

Alajo, Ayodeji Babatunde


Nuclear Engineering and Radiation Science

Degree Name

M.S. in Nuclear Engineering


United States. National Nuclear Security Administration. Office of Nonproliferation and International Security


Dr. Alexis Trahan, LANL mentor


Missouri University of Science and Technology

Publication Date

Summer 2017


x, 77 pages

Note about bibliography

Includes bibliographical references (pages 75-76).


© 2017 Jay Prakash Joshi, All rights reserved.

Document Type

Thesis - Open Access

File Type




Thesis Number

T 11489

Electronic OCLC #