Rickover Fellowship Program in Nuclear Engineering

Donohoue, Collin

School: Colorado School of Mines

Began Rickover Fellowship: September 2008

Lab Assignment: KAPL, Summer 2009

Lab Mentor: Dr. Jake Ballard

Degree(s):
B.S. Metallurgical and Materials Engineering, Colorado School of Mines, 2005

Expected Graduation Date: May 2010

University Advisor: Dr. John J. Moore

Field of Study: Metallurgical Engineering

Email Address: cdonohou@mines.edu

Summary of Research:
This project uses an exothermic combustion synthesis method, termed self-propagating high-temperature synthesis (SHS), to produce high-density readily reproducible nitride fuels and other ceramic type nuclear fuels in conjunction with the fabrication of transmutation fuels. The major research objective of this project is to determine the fundamental process parameters required to optimize and formalize nuclear fuel SHS. This objective is attained through a two-step protocol. In the first step, surrogates of uranium and specific transuranic elements are utilized to produce dense ceramic compounds. The use of surrogates serves to develop fundamental processes, configurations, and optimal parameters to prepare for nuclear fuel SHS. After development of a viable surrogate process, the second step is to transfer this technology to the production of dense ceramic nuclear fuels using uranium and transuranic elements.

The retention of transuranic elements in the fuel pellet is the primary focus of this study. Plutonium and americium, in particular, have high vapor pressures resulting in significant loss of material while undergoing traditional fuel pellet manufacturing techniques such as melting or sintering. Combustion synthesis, also known as self-propagating high-temperature combustion synthesis (SHS), offers an alternative process for the synthesis of transuranic-containing nitride nuclear fuels whereby the rapid heating and cooling rates minimize material loss and maximize production efficiency.

Combustion synthesis involves the mixing of two or more reactant powders that can react exothermically to produce the required ceramic, intermetallic compound, glass or composite material. The reactants are pressed to a certain green density and ignited locally, e.g., at the bottom or top of the compressed pellet. Once ignited, the exothermic reaction generates sufficient energy to rapidly propagate a self-sustaining combustion (exothermic) wave along the green compact. The combustion wave will typically travel along a pellet of 2 inches long and 1 inch in diameter in less than two seconds. Immediately after the reaction, a specified load can be applied compressing the pellet to the desired density, in this case 85 – 95% of theoretical. Presently, surrogates of zirconium for uranium, praseodymium for plutonium, and dysprosium for americium are being used for their similar physical and chemical properties. The reactions are being carried out in nitrogen to form the metal nitrides. Chemistries of fuel pellets provided by Idaho National Laboratory are currently being studied for feasibility. Subsequent steps will include chemistry, and green density optimization as well as densification procedures.

Publications:

A paper entitled “Nitride Nuclear Fuel Production Using Combustion Synthesis” was presented at the American Nuclear Society (ANS) meeting in Boston, June 24-28, 2007.
A paper entitled “Production of Oxide and Nitride Powders Employing Auto-Ignition Combustion Synthesis (AICS)” was presented at the annual International Symposium of Self-Propagating High Temperature Synthesis in Dijon, France in July 2007.
A paper entitled “Application of Combustion Synthesis to the Production of Actinide Bearing Nitride Ceramic Nuclear Fuels” was presented at the annual PCRIM-6 conference in Korea, November, 2007.