TRIGA® Reactors: The Nuclear Reactor in Your School’s Basement
Nuclear research reactors play a vital role in various industries and in training new operators for commercial nuclear reactors. Among these research reactors, the General Atomics’ TRIGA® (Training, Research, Isotopes, General Atomics) reactors are the most widely used non-power nuclear reactors in the world 1 with over 50 operational TRIGA reactors in 23 countries. These “swimming pool” reactors do not require a containment building and are located at the bottom of a deep pool of water to shield operators and to slow neutrons. TRIGA® reactors are generally used as a safe source of neutrons and allow several types of facilities to be installed beside the core with minimal risk to samples and researchers. This also allows each TRIGA® reactor limitless combinations and approaches to neutron-based research and utilization within the capabilities of the reactor. TRIGA® reactors can produce radioisotopes, which are radioactive elements used for research and medicine. This process involves making materials radioactive by bombarding them with neutrons to study their behavior. Furthermore, TRIGA® reactors offer training opportunities that enable students to operate a nuclear reactor with considerably reduced risk.
Renowned physicist Edward Teller, who contributed to the reactor’s design, openly stated that “[the TRIGA®] is safe even in the hands of a young graduate student.” The safety stems from the composition of the fuel, Uranium Zirconium Hydride, used in the TRIGA® reactors. The fuel decreases the reactivity as the temperature increases, effectively preventing any accidental meltdowns regardless of the experience of the operator. The safety and malleability of the TRIGA® reactor make it a perfect reactor for universities to perform research and to train operators. Schools such as Penn State University and Oregon State University have demonstrated the flexibility and potential of these reactors.
The Penn State Breazeale Reactor (PSBR) is one of the oldest operational research reactors in the world, in use since 1955. Originally a Materials Testing Reactor with a more enriched fuel, it was converted to the more powerful TRIGA® reactor in 1965. The unique part of the PSBR is that the bridge structure was redesigned in the mid-1990s to allow for lateral and rotational movement of the reactor core so that it can be positioned almost anywhere in the reactor pool, giving it the ability to perform more tailored experiments and have an exceptional degree of experimental and operational flexibility. The PSBR is used by other facilities at Penn State, such as the neutron beam lab, and as a means of training undergraduate students on reactor operations.
The Oregon State TRIGA® Reactor (OSTR) features a classic TRIGA® design, located at the bottom of a cylindrical water pool with a glass top for observation. It supports a wide variety of experiments using several different facilities nestled beside the core. Another feature of the OSTR is that it can perform a pulse at will. A pulse is when a control rod—the part of the reactor that helps control the nuclear reaction rate—is rapidly removed from the core. When the control rod is removed, the reaction rate and number of neutrons dramatically increases until the fuel corrects itself after a fraction of a second.
The PSBR and OSTR are two brief examples of the many TRIGA® reactors in the world, each one specialized for its type of research. The PSBR is an advanced model capable of maneuvering its reactor in its pool, and the OSTR is a multi-industry resource with a highly customizable facility. Both teams support outreach and regularly offer tours to industry visitors and students from their campuses. Neutron interaction research is crucial for advancing nuclear reactor safety, medical isotope production, radiation shielding, material science, and the fundamental understanding of nuclear forces. This will enable better energy generation, medical treatments, and radiation protection. Even after decades of research, there is still much to learn about neutron interactions with matter. Every TRIGA® reactor in the world furthers these explorations and allows firsthand experience for future reactor operators.
References
General Atomics (n.d.) TRIGA Nuclear Reactors. Retrieved from https://ga.com/triga/
International Atomic Energy Agency (n.d.) Research Reactor Database (RRDB). Retrieved from https://nucleus.iaea.org/rrdb/home
Teller, Edward; Shoolery, Judith L. (2002). Memoirs: a twentieth-century journey in science and politics. Oxford: Perseus Press. p. 423.
Penn State University, College of Engineering, Radiation Science and Energy Center (n.d.) History of the Penn State Breazeale Nuclear Reactor. https://www.rsec.psu.edu/History.aspx
Davis, Will (2012), The MTR—Gone now, but not forgotten. The MTR—Gone now, but not forgotten -- ANS / Nuclear Newswire
Oregon State University, College of Engineering, School of Nuclear Science and Engineering, Radiation Center (n.d.) Welcome to the Radiation Center. https://radiationcenter.oregonstate.edu/