Clarice Phelps

Clarice Phelps

Clarice Evone Phelps (née Salone) is an American chemist and researcher at Oak Ridge National Laboratory. She was part of the team involved with the discovery of element 117, Tennessine. Her research includes actinide and lanthanide separations for medical use isotopes.

Early life and education

Phelps earned a Bachelors degree in chemistry from Tennessee State University in 2003. As of 2019 Phelps is in the Masters Degree program in the Nuclear and Radiation Engineering Program at the University of Texas.

Early in life Phelps says her interest in science was sparked by receiving and microscope and science-based encyclopedia kit from her mother and kindled by teachers.

She is an alumna of the Tennessee Aquatic Project, a youth based organization that provides at-risk and inner city youth personal development tools and uses aquatics and travel as incentives.


In 2004 Phelps joined the United States Navy working as an engineering lab technician. As an Engineering Laboratory Technician with the Navy Nuclear Power Program, she performed chemical and radiological maintenance for two Reactor Plants onboard a nuclear powered aircraft carrier and also was responsible for tracking radiation exposure for over 500 people.

Phelps joined Oak Ridge National Laboratory (ORNL) as a nuclear operation technician in 2009. ORNL is a research laboratory managed by UT-Battelle, LLC, for the U.S. Department of Energy (DOE) which is primarily a facility for open research with user facilities available to researchers from other national labs, academia and industry. Phelps is program manager for the nickel-63 and selenium-75 industrial use isotope programs. Nickel-63 is used for detecting explosives and in some electronic devices such as surge protectors.  Selenium-75 is used in medical imaging. Phelps also performs research on separation and analysis of of elements such as europium, samarium, actinium and lanthanum in the Medical, Industrial and Research Isotopes Group (MIRIG).

Phelps was one of the authors on a technical report for the DOE on the separation of plutonium from uranium using hydroxylamine nitrate (HAN) in 2015. It outlines safe methods to decompose HAN in the reprocessing of nuclear fuel. Phelps is an author on a 2019 report for the DOE titled, “Dissolution of Light Curium Oxide with a Catalyzed Electrolytic Process". The report includes research on a method to improve the curium feed material for more efficient production of transcurium elements and isotopes such as berkelium-249 and californium-252 (Cf-252).

Phelps was the recipient of the 2017 YWCA Knoxville Tribute to Women in the Women technology, research, and innovation category. 

Notable projects to which Phelps has contributed

Phelps collaborated with the Argonne National Laboratory’s Californium Rare Isotope Breeder Upgrade (CARIBU) to electroplate platimum and stainless-steel plates with californium-252 for nuclear fission fragment analysis. CARIBU creates beams of californium-252 fission fragments, neutron-rich isotopes, allowing physicists to study the nuclear structure of atoms.

The NASA plutonium-238 project, performing work on plutonium and neptunium. The radioactive decay of Plutonium-238 (Pu-238) produces a steady heat that is used as an electrical power source for U.S. space missions. 

Phelps participated in the purification of berkelium-249, used to confirm the discovery of element 117, tennessine. Tennessine is a radioactive metal of which only a few atoms of it have ever been made. International Union of Pure and Applied Chemistry (IUPAC) confirmed the discovery by scientists from the Joint Institute for Nuclear Research in Dubna, Russia, the Lawrence Livermore National Laboratory in California, USA, and ORNL.

ORNL produced berkelium with its nuclear reactor and was the only place that could produce berkelium at significant quantities. Phelps was part of a small team, which included Rose Boll and Shelly Van Cleve, that purified berkelium-249, from a 27 milligram sample. Manipulations were performed inside radiation-proof glove boxes to remove specks of impurity that could interfere with the reaction that would make tennessine and the team managed to lose less than a milligram of material in the process. 

Colleagues at the Joint Institute for Nuclear Research in Russia used the purified berkelium-249 to create and confirm the existence of tennessine. Tennessine was produced by bombarding atoms of berkelium-249 with ions of calcium-48. Tennessine is called a super-heavy element since its atomic number is 100 or higher, meaning it has 100 or more protons in its nuclei. Tennessine formed when calcium with atomic number 20 and berkelium with atomic number 97 fused to make an element with 117 protons in its nuclei.

Researchers are interested in superheavy elements to understand the limits of existence of matter. Phelps is mentioned in the book Superheavy: Making and Breaking the Periodic Table by Kit Chapman. She is thought to be the first African American woman to help discover an element. 

Science outreach work

Phelps works with the graduate chapter of Alpha Kappa Alpha sorority’s ASCEND program which teaches Knoxville high school students about robotics, drones, circuitry and coding. Phelps is a member of the American Chemical Society as well as the Educational Outreach Committee for the ORNL as the diversity chair for Knox County Schools.



Related Golden topics

Further reading


Documentaries, videos and podcasts


50 years of excellence at the Radiochemical Engineering Development Center

Clarice Phelps: Dedicated service to science and community