# TRIGA

TRIGA (Training, Research, Isotopes, General Atomics) is a class of nuclear research reactor designed and manufactured by General Atomics. The design team for TRIGA, which included Edward Teller, was led by the physicist Freeman Dyson.

## Design

TRIGA is a swimming pool reactor that can be installed without a containment building, and is designed for research and testing use by scientific institutions and universities for purposes such as undergraduate and graduate education, private commercial research, non-destructive testing and isotope production.
The TRIGA reactor uses uranium zirconium hydride (UZrH) fuel, which has a large, prompt negative fuel temperature coefficient of reactivity, meaning that as the temperature of the core increases, the reactivity rapidly decreases. Because of this unique feature, it has been safely pulsed at a power of up to 22,000 megawatts. The hydrogen in the fuel is bound in the uranium zirconium hydride crystal structure with a vibrational energy of 0.14eV. When the core is hot, these levels fill and transfer energy to any cooler neutrons making them hot and, therefore, less reactive. TRIGA was originally designed to be fueled with highly enriched uranium, but in 1978 the US Department of Energy launched its Reduced Enrichment for Research Test Reactors program, which promoted reactor conversion to low-enriched uranium fuel.

## History

The TRIGA was developed to be a reactor that, in the words of Edward Teller, "is safe even in the hands of a young graduate student." Teller headed a group of young nuclear physicists in San Diego in the summer of 1956 to design an inherently safe reactor which could not, by its design, suffer from a meltdown. The design was largely the suggestion of Freeman Dyson. The prototype for the TRIGA nuclear reactor (TRIGA Mark I) was commissioned on 3 May 1958 on the General Atomics campus in San Diego and operated until shut down in 1997. It has been designated as a nuclear historic landmark by the American Nuclear Society.
Mark II, Mark III and other variants of the TRIGA design have subsequently been produced, and a total of 33 TRIGA reactors have been installed at locations across the United States. Those that remain operational continue to be upgraded/modernized. A further 33 reactors have been installed in other countries. Many of these installations were prompted by US President Eisenhower's 1953 Atoms for Peace policy, which sought to extend access to nuclear physics to countries in the American sphere of influence. Consequently, TRIGA reactors can be found in a total of 24 countries, including Austria, Bangladesh, Brazil, Congo, Colombia, England, Finland, Germany, Taiwan, Japan, South Korea, Italy, Indonesia, Malaysia, Mexico, Morocco, Philippines, Puerto Rico, Romania, Slovenia, Thailand, Turkey, and Vietnam.
TRIGA International, a joint venture between General Atomics and CERCA [fr]—then a subsidiary of AREVA of France—was established in 1996. Since then, all TRIGA fuel assemblies have been manufactured at CERCA's plant in Romans-sur-Isère, France.
Some of the main competitors to General Atomics in the supply of research reactors are Korea Atomic Energy Research Institute (KAERI) of Korea and INVAP of Argentina.
The TRIGA Power System (TPS) is a proposed small power plant and heat source, based upon the TRIGA reactor and its unique uranium zirconium hydride fuel, with a power output of 64 MW$_{th}$ / 16 MW$_e$.

## List of all TRIGA Nuclear reactors built around the world

| Country | City | Name | Type | Status | Thermal Power [kW] | Operation Date | Closure Date | Owner and Operator | Notes |
| Austria | Vienna | TRIGA II VIENNA | TRIGA Mark II | Operational | 250 | 1962-03-07 | | Institute of Atomic and Subatomic Physics | |
| Bangladesh | Savar, Dhaka | BTRR, BAEC TRIGA Research Reactor | TRIGA Mark II | Operational | 3000 | 1986-09-14 | | Atomic Energy Research Establishment (Bangladesh) | |
| Brazil | Belo Horizonte | TRIGA IPR-R1 | TRIGA Mark I | Operational | 100 | 1960-11-06 | | CDTN - Centro de Desenvolvimento de Tecnologia Nuclear | *The expansion to 250 KW is in the licensing process, for which a new refrigeration system has been installed. |
| Colombia | Bogota | IAN-R1 | TRIGA CONV | Operational | 30 | 1965-01-20 | | | |
| Congo, DR of | Kinshasa | TRICO I | TRIGA Mark I | Permanent Shutdown | 50 | 1959-06-06 | 1970 | CREN-K University of Kinshasa | |
| Congo, DR of | Kinshasa | TRICO II | TRIGA Mark II | Extended Shutdown | 1 | 1972-03-24 | | CREN-K University of Kinshasa | extended shut down since 2004 [18] |
| Finland | Espoo | FIR-1 | TRIGA Mark II | Under Decommissioning | 250 | 1962-03-27 | 2015 | VTT Technical Research Centre of Finland | |
| Germany | Frankfurt am Main | FRF-2 | TRIGA Conv | Decommissioned | 1 | 1977-10-01 | | | |
| Germany | Heidelberg | TRIGA HD I | TRIGA Mark I | Decommissioned | 250 | 1966-08-01 | | | |
| Germany | Hannover | FRH | TRIGA Mark I | Decommissioned | 250 | 1973-01-31 | | | |
| Germany | Heidelberg | TRIGA HD II | TRIGA Mark I | Decommissioned | 250 | 1978-02-28 | | | |
| Germany | Mainz | FRMZ | TRIGA Mark II | Operational | 100 | 1965-08-03 | | | |
| Germany | Munich | FRN | TRIGA Mark III | Under Decommissioning | 1 | 1972-08-23 | | | |
| Indonesia | Bandung | TRIGA Mark II, Bandung | TRIGA Mark II | Operational | 2000 | 1964-10-19 | | | 2MW installed 1997 |
| Indonesia | Sleman | KARTINI-PSTA | TRIGA Mark II | Operational | 100 | 1979-01-25 | | | |
| Italy | Rome | TRIGA RC-1 | TRIGA Mark II | Operational | 1 | 1960-06-11 | | | |
| Italy | Pavia | LENA, TRIGA II PAVIA | TRIGA Mark II | Operational | 250 | 1965-11-15 | | | |
| Japan | Tōkai, Ibaraki | NSRR | TRIGA Acpr | Operational | 300 | 1975-06-30 | | | |
| Japan | Yokosuka | TRIGA-II Rikkyo | TRIGA Mark II | Under Decommissioning | 100 | 1961-12-08 | | | |
| Japan | Tokyo | Musashi Reactor | TRIGA Mark II | Under Decommissioning | 100 | 1963-01-30 | | | |
| Korea, Republic of | Seoul | KRR-1 | TRIGA Mark II | Decommissioned | 250 | 1962-03-19 | | KAERI | Research Reactor,100 kW, built 1962 (Decommissioned)[52] |
| Korea, Republic of | Seoul | KRR-2 | TRIGA Mark III | Decommissioned | 2 | 1972-04-10 | | KAERI | Research Reactor, 2MW, BUILT 1972 (Decommissioned)[53] |
| Malaysia | Kajang, Kuala Lumpur | TRIGA Puspati (RTP) | TRIGA Mark II | Operational | 1 | 1982-06-28 | | Malaysian Institute of Nuclear Technology Research | |
| Mexico | La Marquesa Ocoyoacac | TRIGA Mark III | TRIGA Mark III | Operational | 1 | 1968-11-08 | | National Institute for Nuclear Research | |
| Morocco | Rabat | MA-R1 | TRIGA Mark II | Operational | 2 | 2007-05-02 | | | |
| Philippines | Quezon City | PRR-1 | Subcrit (TRIGA-converted) | Operational | 0 | | | | 3 MW TRIGA-converted reactor, Quezon City. Managed by the Philippine Nuclear Research Institute (formerly Philippine Atomic Energy Commission). 1st criticality in August 1963, reactor conversion in March 1984, criticality after conversion in April 1988, shut down since 1988 for pool repairs, on extended shutdown at present. |
| Puerto Rico | | Mayagüez - TRIGA reactor (dismantled) | | Dismantled | | | | | |
| Romania | Pitesti | TRIGA II Pitesti - SS Core | TRIGA Dual Core | Operational | 14 | 1980-02-02 | | | |
| Romania | Pitesti | TRIGA II Pitesti - Pulsed | TRIGA Dual Core | Operational | 500 | 1980-02-02 | | | |
| Slovenia | Ljubljana | TRIGA- MARK II LJUBLJANA | TRIGA Mark II | Operational | 250 | 1966-05-31 | | Jožef Stefan Institute | (web page link) [51] |
| Taiwan | Hsinchu City | THOR | TRIGA Conv | Operational | | 1961-04-13 | | | [56] |
| Thailand | Bangkok | TRR-1/M1 | TRIGA Mark III | Operational | | 1977-11-07 | | Thailand Institute of Nuclear Technology (TINT) | Thai Research Reactor 1/Modification 1, Installed 1962, modified 1975–77. |
| Turkey | Istanbul | ITU-TRR | TRIGA Mark II | Operational | 250 | 1979-03-11 | | Istanbul Technical University | Institute of Energy |
| United Kingdom | Billingham | ICI TRIGA Reactor | TRIGA Mark I | Decommissioned | 250 | 1971-08-01 | 1988 | ICI Physics and Radioisotopes Dept of ICI R&D (later to become Tracerco) | |
| USA | Urbana, IL | LOPRA Univ. Illinois | TRIGA | Decommissioned | 10 | 1971-12-28 | | | |
| USA | San Ramon, CA | ARRR | TRIGA CONV | Operational | 250 | 1964-07-09 | | | |
| USA | Pullman, WA | WSUR Washington State Univ. | TRIGA CONV | Operational | 1000 | 1961-03-07 | | | |
| USA | Madison, WI | UWNR Univ. Wisconsin | TRIGA CONV | Operational | 1000 | 1961-03-26 | | | |
| USA | College Station, TX | NSCR Texas A&M Univ. | TRIGA CONV | Operational | 1000 | 1962-01-01 | | | |
| USA | Mayagüez, Puerto Rico | TRIGA Puerto Rico Nuclear Center | TRIGA CONV | Decommissioned | 2000 | 1972-01-19 | | | |
| USA | State College, PA | PSBR Penn St. Unv. | TRIGA Mark CONV | Operational | 1000 | 1955-08-15 | | | |
| USA | Silver Spring, MD | DORF TRIGA Mark F | TRIGA Mark F | Decommissioned | 250 | 1961-09-01 | | | |
| USA | Bethesda, MD | AFRRI TRIGA | TRIGA Mark F | Operational | 1000 | 1962-01-01 | | | |
| USA | Hawthorne, CA | TRIGA Mark F, Northrop | TRIGA Mark F | Decommissioned | 1000 | 1963-01-01 | | | |
| USA | Omaha, NE | Veterans Affairs RR | TRIGA Mark I | Decommissioned | 20 | 1959-06-26 | | | |
| USA | Salt Lake City, UT | TRIGA Univ. Utah | TRIGA Mark I | Operational | 100 | 1975-10-25 | | | |
| USA | Tucson, AZ | Univ. Arizona TRIGA | TRIGA Mark I | Decommissioned | 100 | 1958-12-06 | | | |
| USA | San Diego, CA | GA-TRIGA I | TRIGA Mark I | Under Decommissioning | 250 | 1958-05-03 | | | |
| USA | San Diego, CA | GA-TRIGA F | TRIGA Mark I | Under Decommissioning | 250 | 1960-07-01 | | | |
| USA | Portland, OR | RRR Reed College | TRIGA Mark I | Operational | 250 | 1968-07-02 | | | |
| USA | Irvine, CA | UC Irvine TRIGA | TRIGA Mark I | Operational | 250 | 1969-11-25 | | | |
| USA | Austin, TX | UT TRIGA Univ. Texas | TRIGA Mark I | Decommissioned | 250 | 1963-01-01 | | | |
| USA | East Lansing, MI | TRIGA Mark I Michigan State Univ. | TRIGA Mark I | Decommissioned | 250 | 1969-03-21 | | | |
| USA | Midland, MI | Dow TRIGA | TRIGA Mark I | Operational | 300 | 1967-07-06 | | | |
| USA | Richland, WA | NRF, Neutron Rad Facility | TRIGA Mark I | Under Decommissioning | 1000 | 1977-03-01 | | | |
| USA | Denver | GSTR US Geological Survey | TRIGA Mark I | Operational | 1000 | 1969-02-26 | | | |
| USA | San Diego, CA | TRIGA Mark II | TRIGA Mark II | Decommissioned | 50 | 1959-12-11 | | | |
| USA | Manhattan, KS | KSU TRIGA Mark II | TRIGA Mark II | Operational | 250 | 1962-10-16 | | | |
| USA | Idaho Falls, ID | NRAD | TRIGA Mark II | Operational | 250 | 1977-10-12 | | | |
| USA | Ithaca, NY | TRIGA Cornell Univ | TRIGA Mark II | Decommissioned | 500 | 1962-01-01 | | | |
| USA | Corvallis, OR | OSTR, Oregon State Univ. | TRIGA Mark II | Operational | 1100 | 1967-03-08 | | | |
| USA | Austin, TX | TRIGA II Univ. Texas | TRIGA Mark II | Operational | 1100 | 1992-03-12 | | | |
| USA | Urbana, IL | Univ. Illinois Advanced TRIGA | TRIGA Mark II | Decommissioned | 1500 | 1969-07-23 | | | |
| USA | Sacramento, CA | UC Davis/McClellan TRIGA | TRIGA Mark II | Operational | 2000 | 1990-01-20 | | | |
| USA | Berkeley, CA | BRR UC Berkeley | TRIGA Mark III | Decommissioned | 1000 | 1966-08-10 | | | |
| USA | San Diego, CA | GA-TRIGA III | TRIGA Mark III | Decommissioned | 2000 | 1966-01-01 | | | |
| USA | College Park, MD | MUTR Univ. Maryland | TRIGA MODIFIED | Operational | 250 | 1960-12-01 | | | |
| USA | Albuquerque, NM | ACRR Annular Core RR | TRIGA MODIFIED | Operational | 2400 | 1967-06-01 | | | |
| Vietnam | Da Lat | Dalat Research Reactor | TRIGA Mark II | Operational | 500 | 1963-02-26 | | | (supplied by USA 1963, shut down 1975, reactivated by USSR 1984) |