Doctoral Dissertations

Keywords and Phrases

Phase Change Materials; Radiation Damage; Thermal Properties


"This work discusses the effects of radiation damage on organic phase change materials for use in nuclear reactor containments and space craft. The effects of radiation on the latent heat of polyethylene wax (PEW) and a eutectic of methyl palmitate and lauric acid (EMPaLA) are evaluated. These PCMs were irradiated in three locations: the Missouri University of Science and Technology research reactor (MSTR), the University of Missouri research reactor (MURR) and cyclotron (MUC) up to a total dose of 2826, 2895 and 662 Gy, respectively. The samples irradiated at the MSTR showed latent heat changes up to 15.5% lower than the starting values however the error bars are so close that the there is no conclusive evidence for a statistically significant change. The MUC irradiation did not yield any statistically significant change in the latent heat. The irradiation at MURR showed a drop of 18.8% which could indicate a dose rate effect. Raman spectra were also taken of the irradiated samples. PEW was found to have a a new peak at about 150 cm-1 when irradiated at MUC but no other observable changes were found. A statistical model was developed to calculate chain length distribution after irradiation by utilizing a displacements per atom (DPA) approach. This model was intended to extrapolate the change in latent heat from the change in molecular chain length. The current model only accounts for scissions and neglects any crosslinking that could occur. The model was found to have an absolute error of under 0.15 at the starting chain length when compared to a similar model developed by Charlesby. It was found that the current model predicts that there will be minimal change in the starting chain lengths which indicates no significant change in the latent heat. This agrees with the data found"--Abstract, page iv.


Schlegel, Joshua P.

Committee Member(s)

Alajo, Ayodeji Babatunde
Castano Giraldo, Carlos Henry
Fahrenholtz, William
Graham, Joseph T.
Wen, Haiming


Nuclear Engineering and Radiation Science

Degree Name

Ph. D. in Nuclear Engineering


This paper is based upon work supported by the U.S. Nuclear Regulatory Commission, Nuclear Education Program under Award NRC-HQ-13-G-38-0026.


Missouri University of Science and Technology

Publication Date

Summer 2021

Journal article titles appearing in thesis/dissertation

  • Neutron and gamma radiation effects on thermal storage properties of polyethylene wax
  • Neutron and gamma radiation effects on thermal storage properties of an organic eutectic PCM
  • Statistical damage model for organic molecules


xvi, 135 pages

Note about bibliography

Includes bibliographic references.


© 2021 Ryan Phillip Steere, All rights reserved.

Document Type

Dissertation - Open Access

File Type




Thesis Number

T 11925

Electronic OCLC #