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Picture of a TRIGA reactor core. The blue glow is caused by Cherenkov radiation.

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.


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.[1] The hydrogen in the fuel is bound in the uranium zirconium hydride crystal structure with a vibrational energy of 0.14eV.[2] 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. [3] [4]


A TRIGA Mark II taken into use at Helsinki University of Technology in 1962 by the Finnish President Urho Kekkonen.

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."[5] 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.[6] 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 MWth / 16 MWe.[7][8]

List of all TRIGA Nuclear reactors built around the world[edit]

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 Atomic Institute of the Austrian Universities in Vienna
Bangladesh Savar, Dhaka BTRR, BAEC TRIGA Research Reactor TRIGA Mark II Operational 3000[9] 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
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
Heidelberg TRIGA HD I TRIGA Mark I Decommissioned 250 1966-08-01
Hannover FRH TRIGA Mark I Decommissioned 250 1973-01-31
Heidelberg TRIGA HD II TRIGA Mark I Decommissioned 250 1978-02-28
Mainz FRMZ TRIGA Mark II Operational 100 1965-08-03
Munich FRN TRIGA Mark III Under Decommissioning 1 1972-08-23
Indonesia Bandung TRIGA Mark II, Bandung TRIGA Mark II Operational 2 1964-10-19 2MW installed 1997
Yogyakarta KARTINI-PSTA TRIGA Mark II Operational 100 1979-01-25
Italy Rome TRIGA RC-1 TRIGA Mark II Operational 1 1960-06-11
Pavia LENA, TRIGA II PAVIA TRIGA Mark II Operational 250 1965-11-15
Japan Tōkai, Ibaraki NSRR TRIGA Acpr Operational 300 1975-06-30
Yokosuka TRIGA-II Rikkyo TRIGA Mark II Under Decommissioning 100 1961-12-08
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]
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
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 1900-01-01 1961-04-13 [56]
Thailand Bangkok TRR-1/M1 TRIGA Mark III Operational 1899-12-31 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
San Ramon, CA ARRR TRIGA CONV Operational 250 1964-07-09
Pullman, WA WSUR Washington State Univ. TRIGA CONV Operational 1000 1961-03-07
Madison, WI UWNR Univ. Wisconsin TRIGA CONV Operational 1000 1961-03-26
College Station, TX NSCR Texas A&M Univ. TRIGA CONV Operational 1000 1962-01-01
Mayagüez, Puerto Rico TRIGA Puerto Rico Nuclear Center TRIGA CONV Decommissioned 2000 1972-01-19
State College, PA PSBR Penn St. Unv. TRIGA Mark CONV Operational 1000 1955-08-15
Silver Spring, MD DORF TRIGA Mark F TRIGA Mark F Decommissioned 250 1961-09-01
Bethesda, MD AFRRI TRIGA TRIGA Mark F Operational 1000 1962-01-01
Hawthorne, CA TRIGA Mark F, Northrop TRIGA Mark F Decommissioned 1000 1963-01-01
Omaha, NE Veterans Affairs RR TRIGA Mark I Decommissioned 20 1959-06-26
Salt Lake City, UT TRIGA Univ. Utah TRIGA Mark I Operational 100 1975-10-25
Tucson, AZ Univ. Arizona TRIGA TRIGA Mark I Decommissioned 100 1958-12-06
San Diego, CA GA-TRIGA I TRIGA Mark I Under Decommissioning 250 1958-05-03
San Diego, CA GA-TRIGA F TRIGA Mark I Under Decommissioning 250 1960-07-01
Portland, OR RRR Reed College TRIGA Mark I Operational 250 1968-07-02
Irvine, CA UC Irvine TRIGA TRIGA Mark I Operational 250 1969-11-25
Austin, TX UT TRIGA Univ. Texas TRIGA Mark I Decommissioned 250 1963-01-01
East Lansing, MI TRIGA Mark I Michigan State Univ. TRIGA Mark I Decommissioned 250 1969-03-21
Midland, MI Dow TRIGA TRIGA Mark I Operational 300 1967-07-06
Richland, WA NRF, Neutron Rad Facility TRIGA Mark I Under Decommissioning 1000 1977-03-01
Denver GSTR US Geological Survey TRIGA Mark I Operational 1000 1969-02-26
San Diego, CA TRIGA Mark II TRIGA Mark II Decommissioned 50 1959-12-11
Manhattan, KS KSU TRIGA Mark II TRIGA Mark II Operational 250 1962-10-16
Idaho Falls, ID NRAD TRIGA Mark II Operational 250 1977-10-12
Ithaca, NY TRIGA Cornell Univ TRIGA Mark II Decommissioned 500 1962-01-01
Corvallis, OR OSTR, Oregon State Univ. TRIGA Mark II Operational 1100 1967-03-08
Austin, TX TRIGA II Univ. Texas TRIGA Mark II Operational 1100 1992-03-12
Urbana, IL Univ. Illinois Advanced TRIGA TRIGA Mark II Decommissioned 1500 1969-07-23
Sacramento, CA UC Davis/McClellan TRIGA TRIGA Mark II Operational 2000 1990-01-20
Berkeley, CA BRR UC Berkeley TRIGA Mark III Decommissioned 1000 1966-08-10
San Diego, CA GA-TRIGA III TRIGA Mark III Decommissioned 2000 1966-01-01
College Park, MD MUTR Univ. Maryland TRIGA MODIFIED Operational 250 1960-12-01
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)

See also[edit]


  1. ^ TRIGA® Nuclear Reactors General Atomics
  2. ^ TRIGA® Nuclear Reactors General Atomics
  3. ^ Argonne National Laboratory. "RERTR Radiological Threat Reduction Program". Retrieved 2013-12-09.
  4. ^ "Global Threat Reduction Initiative - Strategic Plan January 2009" (PDF). Retrieved 16 February 2018.
  5. ^ Teller, Edward; Shoolery, Judith L. (2002). Memoirs: a twentieth-century journey in science and politics. Oxford: Perseus Press. p. 423. ISBN 9780738207780.
  6. ^ "New Console Installed at U's Triga Reactor". 29 October 2020.
  7. ^ UxC webpage about the TRIGA Power System
  8. ^ Triga Power System: A Passive Safe Co-Generation Unit for Electric Power and Low Temperature Heat, Small Reactors for Low Temperature Heat Applications, IAEA-TECDOC-463 (International Atomic Energy Agency, Vienna, 1988) pp. 45-55
  9. ^ "Centre for Research Reactor".


External links[edit]