(from "Operational Accidents and Radiation Exposure Experience Within
the United States Atomic Energy Commission, 1943-1970," (WASH 1192), U. S.
Government Printing Office, Washington, D.C., 1971.)
Date | Location | Active
Material | Geometry | Total Fissions | Cause | Physical
Damage | $ Loss |
Aug. 21,
1945 | Los Alamos, New Mexico | 6.2 Kg delta-phase Pu | Spherical core tungsten-carbide reflected | ~1016 | Hand
stacking reflector | None | - |
May 21, 1946
| Los Alamos, New Mexico | 6.2 Kg delta-phase Pu | Spherical core, Be reflected | ~ 3 x 1015 | Hand stacking reflector | None | - |
Apr. 18,1952
| The Los Alamos Scientific Lab., New Mexico
| 92.4 Kg uranium metal , 93% U-235 | Cylinder unreflected | 1.5
x l0l6 | Computation error | None | - |
Feb. 3,1954
| The Los Alamos Scientific Lab., New Mexico
| 53 Kg uranium metal, 93% U-235 | Sphere unreflected | 5.6
x l0l6 | | Slight warping of pieces | $600 |
Feb. 12,1957
| The Los Alamos Scientific Lab., New Mexico
(GODIVA) | 54 Kg uranium metal, 93% U-235
| Sphere unreflected except for experiment
| 1.2 x l0l7 | Shift of experiment | Warping,
oxidation near melting closeto center | $2,400
|
Nov. 10,1961
| The Oak Ridge National Lab., Tennessee
| 75 Kg uranium metal, 93% U-235 | | ~1016
| Too rapid assembly | None | - |
Mar. 26,
1963 | LRL Livermore Calif. | 47 Kg 93% U-235 | Cylinder
reflected | 5 x l0l7 | Too rapid assembly | Assembly
machine and fire effects | $94,881 |
Date | Location | Active
Material | Geometry | Total Fissions | Cause | Physical
Damage | $ Loss |
Dec., 1949
| The Los Alamos Scientific Lab., New Mexico
| ~ 1 Kg U-235 UO2(NO3)2
in 13.6 liters water | Sphere graphite
reflected | 3-4 x 1016 | Manual withdrawal of two poison control rods | None | - |
Nov. 16,
1951 | The Hanford Works, Richland,
Washington | 1.15 Kg Pu PuO2( N03
)2 in 63.8 liters water | Sphere
93% full unreflected | 8 x l0l6
| Poison control rod run out too fast | None | ** |
May 26, 1954
| The Oak Ridge National Lab., Tennessee
| 18. 3 Kg U-235 U02F2
in 55.4 liters water | Cylindrical annulus
unreflected | 1 x 1017 | Tilting of inner poison cylinder | None | - |
Feb. 1, 1956
| The Oak Ridge National Lab., Tennessee
| 27.7 Kg U-235 U02F2
in 58.9 liters water | Cylinder unreflected
| 1.6 x 1017 | Falling scram set up waves creating a critical
geometry | Warping of bottom of cylinder | - |
June 16,
1958 | Y-12 Processing Plant, Oak Ridge.
Tennessee | 2.5 Kg U-235 UO2(NO3)2
in 56 liters water | Cylinder concrete
reflected below | 1.3 x 1018 | Wash water added to U02(NO3)2
solution | None | $1,000 |
Dec. 30,
1958 | The Los Alamos Scientific Lab., New
Mexico,Pu Processing Plant | 3.27 Kg Pu PuO2(
N03 )2 in ~ 168 liters water | Cylinder water reflected below | 1.5 x 1017 | Agitator created a critical geometry | None | - |
Oct. 16,
1959 | Chemical Processing Plant, Idaho
Reactor Testing Area | 34.5 Kg U-235 ~800
liters UO2(NO3)2 water | Cylinder concrete reflected below | ~4 x 1019 | Solution surged from safe to unsafe geometry | None | $61,800 (to
recover contam. solution) |
Jan. 25,
1961 | Chemical Processing Plant, Idaho
Reactor Testing Area | 8 Kg U-235 UO2(NO3)2
in 40 liters water | Cylinder | 6 x 1017 | Solution
pumped from safe to unsafe geometry | None | $6,000 |
Apr. 7, 1962
| Hanford Atomic Products | Pu Solution | Cylinder
| 8 x 1017 | Solution over flow down unsafe geometry transfer
tank | | $1,000
|
Jan. 30,
1968 | Y-12 Processing Plant, Oak Ridge.
Tennessee | 3.3 Kg U-235 UO2(NO3)2
in 20 liters water | Sphere water reflected
| 1.1 x 1016 | Solution surged from safe to unsafe geometry | None | - |
Date | Location | Active
Material | Geometry | Total Fissions | Cause | Physical
Damage | $ Loss |
June 4, 1945
| Los Alamos, New Mexico | 35.4 Kg uranium ~83%, U-235 1/2-in. cubes | Pseudosphere water reflected | ~3 x 1016 | Water seeping between blocks | None | - |
Mar. 20,
1951 | The Los Alamos Scientific Lab., New
Mexico | 2 cylinders uranium 24.4 and 38.5 Kg
93% U-235 | 2 cylinders water reflected | 1017 | Scram
increased reactivity | Slight oxidation | - |
June 2, 1952
| The Argonne National Lab. | 6.8 Kg U-235 oxide particles in plastic | Inhomogeneous cylinder water reflected | 1.22 x 1017 | Manual withdrawal of central safety rod | Plastic destroyed | - |
July 22,
1954 | The Reactor Testing Area, Idaho
Falls, Idaho (BORAX) | U-Al plates clad with
Al | Inhomogeneous cylinder water moderated
| 4.68 x 1018 | Estimate of expected excursion too low | Reactor destroyed intentionally by test | - |
Jan. 3, 1961
| Idaho Reactor Testing Area (SL-1) | U-Al plates clad with Al | Inhomogeneous cylinder water moderated | 1.5 x 1018 | Under study | Extensive
to reactor | $4,350,000 |
* For additional information on these accidents, see previous TID-5360
series and "A Review of Criticality Accidents" by W. R. Stratton,