Nuclear Heritage

INL’s 52 Reactors

In 1949, the U.S. Atomic Energy Commission had 400,000 acres of mostly public lands in east-central Idaho’s high desert set aside to serve as home to the National Reactor Testing Station. Very quickly, organizations from across the country began to design, construct and operate experimental and test reactors on the NRTS. The first three projects—the Experimental Breeder Reactor-I, the Materials Testing Reactor, and the Submarine Thermal Reactor—began operating in 1951, 1952 and 1953, respectively. For many years NRTS contained the largest concentration of nuclear reactors in the world. The alphabetical listing of Idaho-based reactors below is from “Proving the Principle” by author and historian Susan M. Stacy.

Advanced Test Reactor (No. 3) is used to study the effects of radiation on materials and is also capable of producing rare and valuable medical and industrial isotopes. It is the most versatile test reactor in the world.

1. Advanced Reactivity Measurement Facility No. 1. (10/60-1974)
2. Advanced Reactivity Measurement Facility No. 2 (12/62-1968)
3. Advanced Test Reactor (7/67-present)
4. Advanced Test Reactor Critical Facility (5/64-present)
5. Argonne Fast Source Reactor (10/59-late 1970s)
6. Boiling Water Reactor Experiment No. 1 (1953-7/54)
7. Boiling Water Reactor Experiment No. 2 (10/54-3/55)
8. Boiling Water Reactor Experiment No. 3 (6/55-1956)
9. Boiling Water Reactor Experiment No. 4 (12/56-6/58)
10. Boiling Water Reactor Experiment No. 5 (2/62-9/64)
11. Cavity Reactor Critical Experiment (5/67-early 1970s)
12. Coupled Fast Reactivity Measurement Facility (1968-1991)
13. Critical Experiment Tank (1958-1962)
14. Engineering Test Reactor (9/57-12/81)
15. Engineering Test Reactor Critical Facility (5/57-1982)
16. Experimental Beryllium Oxide Reactor (never operated)
17. Experimental Breeder Reactor No. 1 (8/51-12/63)
18. Experimental Breeder Reactor No. 2 (9/61-9/94)
19. Experimental Organic Cooled Reactor (never operated)
20. Fast Spectrum Refractory Metals Reactor (3/62-1968)
21. Gas Cooled Reactor Experiment (2/60-4/61)
22. Heat Transfer Experiment No. 1 (11/55-1956)
23. Heat Transfer Experiment No. 2 (7/57-3/61)
24. Heat Transfer Experiment No. 3 (1958-12/60)
25. High Temperature Marine Propulsion Reactor (1952-1964)
26. Hot Critical Experiment (1958-3/61)
27. Large Ship Reactor A (10/58-1/94)
28. Large Ship Reactor B(7/59-1987)


Submarine Thermal Reactor (No. 45) was the prototype power plant for the nation’s first nuclear submarine, the USS Nautilus.

29. Loss of Fluid Test Reactor (1973-7/85)
30. Materials Testing Reactor (3/52-4/70)
31. Mobile Low-Power Reactor No. 1 (3/61-5/64)
32. Natural Circulation Reactor (9/65-5/95)
33. Neutron Radiography Facility (continuing)
34. Nuclear Effects Reactor (8/68-6/70)
35. Organic Moderated Reactor Experiment (9/57-4/63)
36. Power Burst Facility (9/72-1985)
37. Reactivity Measurement Facility (2/54-4/62)
38. Shield Test Pool Facility (early 1960s)
39. Special Power Excursion Reactor Test No. I (6/55-1964)
40. Special Power Excursion Reactor Test No. II (3/60-10/64)
41. Special Power Excursion Reactor Test No. III (12/58-6/68)
42. Special Power Excursion Reactor Test No. IV (7/62-8/70)
43. Spherical Cavity Reactor Critical Experiment (11/72-1973)
44. Stationary Low-Power Reactor (8/58-1/61)
45. Submarine Thermal Reactor (3/53-10/89)
46. Systems for Nuclear Auxiliary Power (SNAP) 10A Transient No. 1 (early 1960s)
47. Systems for Nuclear Auxiliary Power (SNAP) 10A Transient No. 3 (4/64-4/64)
48. Systems for Nuclear Auxiliary Power (SNAP) 10A Transient No. 2 (1965-1/66)
49. Thermal Reactor Idaho Test Station (last operated in 1964)
50. Transient Reactor Test Facility (2/59-4/94)
51. Zero Power Physics Reactor (4/64-4/92)
52. Zero Power Reactor No. 3 (10/55-11/70)