This day in US nuclear accidents

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11 May

1966 – F-104 / Tonopah, Nevada

An inert bomb test unit intended for drop at the AEC's Tonopah Test Range was dropped off-range by an F-104 between Lathrop Wells and Beatty, Nevada, approximately 80 miles southwest of the target area. The aircraft was flying at an altitude of 35,000 feet at a speed of Mach 1.2 when the incident occurred.

The test unit did not contain any internal classified components, but the construction of its nose was classified as confidential formerly-restricted data. Unclassified depleted uranium weighing about 202 lbs. was used for weight simulation in the unit. An unsuccessful search for the lost device was conducted; the Air Force eventually declared the item irretrievably lost.

Chuck Hansen, “The Swords of Armageddon,” Vol. VII, pp.284-285.

 

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12 - 13 May

No reported incidents.

 

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14 May

1964 – Altus AFB, near Frederick, Oklahoma

An ATLAS F ICBM in silo 577-6 assigned to Altus AFB exploded in its silo.

Chuck Hansen, “The Swords of Armageddon,” Vol. VII, p.275.
Atlas Missile Silo Coordinates

 

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15 - 20 May

No reported incidents.

 

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21 May

1946 - Los Alamos National Laboratory, Los Alamos, New Mexico, USA
– Accidental criticality.

While demonstrating his technique to visiting scientists at Los Alamos, Canadian physicist Louis Slotin manually assembled a critical mass of plutonium. A momentary slip of a screwdriver caused a prompt critical reaction. Slotin died on May 30 from massive radiation poisoning, with an estimated dose of 1,000 rads (rad), or 10 grays(Gy). Seven observers, who received doses as high as 166 rads, survived, yet three died within a few decades from conditions believed to be radiation-related.

List of military nuclear accidents - Wikipedia

The blue flash

 

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22 May

1957 – B-36 / Kirtland AFB, Albuquerque, New Mexico

The aircraft was ferrying an unarmed MK 17 weapon and its nuclear capsule from Biggs AFB, near El Paso, Texas, to Kirtland AFB. At 11:50 AM MST, while approaching Kirtland at an altitude of 1,700 feet, the weapon was accidentally dropped from the aircraft, taking the bomb bay doors with it. The release mechanism locking pin was being removed at the time of release. It was standard procedure at that time to remove the locking pin during takeoff and landing to permit emergency jettison of the weapon, if necessary.

Weapon parachutes were partially deployed but did not fully retard the fall of the bomb because of the low altitude. The bomb fell onto land owned by the University of New Mexico, approximately 4.5 miles south of the Kirtland AFB control tower and 0.3 miles west of the AEC's Sandia Reservation. HE in the bomb's primary detonated when the massive secondary slid forward on weapon impact, completely destroying the bomb and making a crater approximately 25 feet in diameter and 12 feet deep, and raising a cloud of dust and smoke 1,500 feet high. Debris consisting of case sections was scattered over the surrounding mesa up to a mile from the impact point.

Recovery and cleanup were conducted by Field Command, Armed Forces Special Weapons Project (FCAFSWP). The weapon's secondary was recovered essentially intact after being found buried just beneath the floor of the crater, its lower half embedded in hardpan. Radiological survey at the of the area disclosed no radioactivity beyond the lip of the crater at which point the level was 0.5 milliroentgens. There were no health or safety problems. The nuclear capsule was recovered from the aircraft.

Chuck Hansen, “The Swords of Armageddon,” Vol. VII, pp.242-243.

1962 – Chico, California, USA – Explosion of Titan I ICBM in silo in Chico, California.

Titan I ICBM explodes in its silo in Chico, California. During a contractor checkout, a leak and subsequent explosion occurred at launcher 1 at complex 4C at Chico, destroying a Titan I and causing heavy damage to the silo. The Air Force concluded that the two separate explosions occurred because of a blocked vent and blocked valve. All contractors and crew of the silo escaped unharmed.

List of military nuclear accidents - Wikipedia
Titan I 851-C Missile Silo Beale AFB California

1968 - U.S.S. SCORPION / At sea, Atlantic Ocean

The nuclear-powered SKIPJACK-class attack submarine U.S.S. SCORPION (SSN-589) was lost at sea with all hands (99 men) while running submerged approximately 400 miles southwest of the Azores Islands. The vessel was returning from deployment in the Mediterranean Sea to her homeport in Norfolk, Virginia when vibration started a fire inside a faulty battery in a MK 37 conventional torpedo and led to a low-order detonation of the warhead, which in turn blew hatches in the torpedo room compartment, leading to uncontrollable flooding and subsequent rapid sinking. Battery fires in MK 37 torpedoes had occurred earlier aboard other submarines.

Underwater sensors off the east coast of the U.S. detected the sounds of the explosion and subsequent breakup of the submarine as it sank. The relatively-intact hull, broken into two major sections, was located in 10,000 feet of water on October 30, 1968; photographs taken by underwater cameras showed the missing torpedo room hatches. The Navy was not able to definitely ascertain the cause of the torpedo explosion; other weapons aboard the SCORPION, including two MK 45 ASTOR torpedoes armed with W-34 warheads, were not recovered.

Chuck Hansen, “The Swords of Armageddon,” Vol. VII, p.288.

 

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23 May

No reported incidents.

 

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24 - 31 May

No reported incidents.

 

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Unknown date in June

1958 – F-102 / Near Hamilton AFB, Novato, California

A pair of dummy MB-1 rockets were accidentally jettisoned into San Pablo Bay, California; both were later recovered. There were no warheads on the rockets.

Chuck Hansen, “The Swords of Armageddon,” Vol. VII, p.251

1962 – TITAN I missile / Ellsworth AFB, South Dakota

Due to a personnel error during a maintenance operation, a cable between the missile and the silo was disconnected, resulting in ignition of the interstage separation rockets which lifted the second stage of the TITAN off the first stage, causing substantial damage. There was no fire or personnel injury; the rocket was not carrying a war-reserve warhead, so the incident was not reported to the AEC. (Not a "Broken Arrow" incident.)

Chuck Hansen, “The Swords of Armageddon,” Vol. VII, p.270.
Titan I Missile Silo Coordinates

1 June

1963 – ATLAS F missile / Walker AFB, near Roswell, New Mexico

The missile launch crew was completing a normal training exercise which involved preparation of the missile for flight. The exercise included loading both liquid oxygen (lox) and fuel aboard the ATLAS; because of this, no warhead was installed. The crew had begun unloading lox from the rocket preparatory to re-installing the warhead; due to a defective lox drain valve, a fire started in a main lox filter, possibly due to the presence of hydrocarbon contaminants.

The main lox tank then ruptured, allowing its upper portion to fall and rupture the fuel tank below. The mixture of fuel and lox then exploded and threw two 80-ton silo doors about 70 feet. The fire burned for 12 hours, causing severe damage to the missile silo. There were no personnel injuries as a result of the incident and the adjacent launch control center was essentially undamaged. (Not a "Broken Arrow" incident.)

Chuck Hansen, “The Swords of Armageddon,” Vol. VII, p.272.
Atlas Missile Silo Coordinates

 

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2 - 3 June

No reported incidents.

 

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4 June

1959 – Railroad train / Near Remington, Indiana

A special train shipment carrying assembled nuclear weapons left Burlington, Iowa at 2:00 AM CST on June 4. At 12:40 PM CST on the Pennsylvania Railroad in open farm country one and a half miles west of Remington, Indiana and about six miles east of Goodland, Indiana, the last of nine special freight cars and a trailing "buffer" car derailed at a speed of 45 MPH. There was no damage to the contents of the freight car and it was placed back on the tracks and was again enroute by 7:10 PM CST on June 4. No press release was issued.

Chuck Hansen, “The Swords of Armageddon,” Vol. VII, p.254.

1962 - THOR missile / Johnston Island, Pacific Ocean

During an attempt to conduct a high-altitude thermonuclear explosion, the THOR launch vehicle and its W-49 warhead were deliberately destroyed in flight at an altitude of 25 miles. The warhead and re-entry vehicle fell into deep water and no recovery was attempted.

Chuck Hansen, “The Swords of Armageddon,” Vol. VII, p.270.

 

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5 - 6 June

No reported incidents.

 

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7 June

1960 – BOMARC / McGuire AFB, near Trenton, New Jersey

A BOMARC IM-99A air defense missile in ready storage condition with a W-40 warhead installed in its enclosed 20 by 40 foot cement shelter (permitting launch in two minutes) was destroyed around 3:15 PM EDT in its launching shelter by explosion and fire after a high-pressure helium tank used to pressurize fuel tanks exploded and ruptured the missile's liquid fuel tanks. The fire apparently started in the missile fuel storage area, housed about 20 feet from the missile inside the shelter.

When emergency personnel arrived at the missile shelter, the BOMARC was burning and no attempt could be made to bring the fire under control. Water hoses were placed through the shelter doors before firefighters were evacuated due to fear of an explosion; they returned about a half hour later and contained the fire. A five to eight knot northeast wind was blowing, sending smoke from the fire off-base.

At approximately 7:15, decontamination personnel entered the shelter. The nose section of the missile was still smoldering, and approximately an inch of water covered the shelter floor and was pouring into a drainage ditch. A reading of 250 counts per minute was detected directly under the warhead; water apparently shielded other readings.

The roof directly above the fuel storage area was completely burned. The W-40 missile warhead was also destroyed by the fire although the HE in the warhead did not detonate. The HE burned with jet fuel, creating an intense “super heat” for nearly an hour. The plutonium in the warhead pit melted and puddled under the burnt-out missile, along with aluminum slag and oxides. No explosive residue was found. The warhead's tritium reservoir was recovered intact and appeared to be in good condition.

Nuclear safety devices in the warhead functioned as intended. Alpha particle contamination from the plutonium in the warhead was restricted to an area immediately beneath the weapon and to an adjacent elongated area approximately 100 feet long, carried by smoke and run-off of water used to fight the fire. A high reading of 160,000 counts per minute was found in this area; a reading of over 2,000,000 counts per minute was detected in the warhead residue. Other areas within the shelter gave readings between 100 to 50,000 counts per minute.

No ground contamination was found beyond 100 feet from the accident location. (Other reports state that contamination covered several acres; although the smoke from the fire was not monitored, 66 square miles of off-base area was surveyed by the Public Health Service which found no traces of radioactive contamination.)

Runoff water was absorbed within sandy soil approximately 500 feet from the fire. A dam was constructed to insure that the water did not leave the base.

The contaminated area was plowed under and later covered with two inches of concrete. The remains of the warhead, tritium reservoir, and pit residue from the missile shelter were placed in plastic bags, put into sealed containers, double-wrapped, and shipped to AEC laboratories. Both the inside and outside of the shelter were painted with thick coats of paint.

During the summer of 1999, the Air Force contracted with a South Carolina company to remove 8,000 cubic yards of soil and 500 to 600 cubic yards of concrete and pavement believed to still be contaminated with plutonium. By late July 2001, $6.5 million was to be spent to remove approximately 12,000 cubic yards of soil and 440 cubic yards of building debris staring in the spring of 2002. The debris was to be transported by truck and rail, probably to a DOE waste site in South Carolina.

Chuck Hansen, “The Swords of Armageddon,” Vol. VII, pp.258-260.

 

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8 - 15 June

No reported incidents.

 

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16 June

1956 - June 16, 1956 / C-124 / Eniwetok atoll, Pacific Ocean

An inbound MATS C-124 carrying nuclear test device components (possibly for the EGG device fired during the Operation REDWING Mohawk test) crashed 421 feet short of, and eight feet below, the runway at Eniwetok island, shearing off its landing gear and coming to rest 2,000 feet from the southeast end of the runway. A fire that ensued was extinguished within three hours. There was no loss of life, and most of the cargo, although damaged by water and foam, was recovered. The runway was cleared of wreckage and reopened to normal traffic before noon on June 17. Salvage of certain aircraft components was accomplished by a team from Hickam AFB, Hawaii.

Chuck Hansen, “The Swords of Armageddon,” Vol. VII, p.242

 

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17 - 18 June

No reported incidents.

 

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19 June

1957 – Navy plane / Off Jacksonville, Florida

A U. S. Navy plane jettisoned “an atomic bomb (that) did not (contain) fissionable material.” The Navy attempted to recover the weapon.

Chuck Hansen, “The Swords of Armageddon,” Vol. VII, p.243

 

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20 June

1962 - THOR missile / Johnston Island, Pacific Ocean

During a second attempt to conduct a high-altitude thermonuclear explosion, the THOR launch vehicle and its W-49 warhead were deliberately destroyed in flight at an altitude between 30,000 and 35,000 feet. Plutonium from the W-49 warhead contaminated Sand Island near Johnston.

Chuck Hansen, “The Swords of Armageddon,” Vol. VII, p.270.

 

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21 June

1961 – DOD weapons storage facility

(Date approximate) An incident occurred involving flooding of a nuclear weapons storage facility caused by a flash flood resulting from more than four inches of rain falling in less than three hours. The weapons were inundated for periods ranging from 40 minutes to two hours. Tests indicated that the warheads were acceptable for use without repair. A number of MK 28 components were involved, including MK 28 Mod 1 fuses, MK 28EX external shape components, and MK 28RE retarded external shape components. Based on initial examination of these major assemblies, it appeared that all could be repaired by cleaning or replacing certain components. These weapons were returned to the AEC’s Medina Modification Center for cleanup or component replacement. The site drainage system was revised to prevent future flooding.

Chuck Hansen, “The Swords of Armageddon,” Vol. VII, pp.267-268.

 

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22 - 30 June

No reported incidents.