This day in US nuclear accidents

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Unknown date October

1960 – (2) A MK 28EX or MK 28RE weapon was damaged during unloading from a strike aircraft. No aircraft power had been applied to the weapon, and the arm-safe switch was in the “safe” position.

Chuck Hansen, “The Swords of Armageddon,” Vol. VII, p.261


1975 – – Apra Harbor, Guam – Spill of irradiated water

While disabled, the submarine tender USS Proteus (AS-19) discharged radioactive coolant water. A Geiger counter at two of the harbor's public beaches showed 100 millirems/hour, fifty times the allowable dose.

List of military nuclear accidents - Wikipedia

 

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1 - 3 October

No reported incidents.

 

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4 October

1960 – SM-78 JUPITER missile / Italy

At 115 Zulu hours, during warhead installation and checkout operations, three explosive bolts on the left side of the missile accidentally fired, causing separation of the missile nose cone and MK 49 Alt 202 warhead from the missile. The missile was in an unerected horizontal position, resulting in a six to 10 foot drop of warhead and nose cone. Inspection of the warhead revealed no visible defects. No evidence of tritium gas escape was found during a subsequent warhead disassembly. Nose cone and warhead were returned to a local assembly area, then back to the continental U.S.

The bolts were fired by a power surge caused by a short circuit in connector plugs due to moisture infiltration and corrosion. All JUPITER missiles with mated warheads were placed on standby alert until all similar components could be checked.

Chuck Hansen, “The Swords of Armageddon,” Vol. VII, p.261.

 

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5 - 10 October

No reported incidents.

 

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11 October

1957 – B-47 / Homestead AFB, near Homestead, Florida

A B-47 participating in a large scale operational support exercise departed Homestead AFB shortly after midnight on a REFLEX deployment mission. Soon after takeoff, around 5:16 AM local time, one of the aircraft's outrigger tires exploded. The aircraft crashed and burned, killing four crewmen, in an open field approximately 3,800 feet from the end of the runway.

The B-47 was carrying in its bomb bay one MK 15/39 weapon in ferry configuration and one nuclear capsule in an M-102 “birdcage” carrying case in the crew compartment. The “birdcage” and capsule were retrieved intact, only slightly singed, before the aircraft wreckage became engulfed in flames. The weapon was enveloped in flames and burned and smoldered for approximately four hours after which it was cooled with water. Two low-order HE detonations occurred during the fire. Approximately one-half of the weapon remained after the fire was extinguished.

All major weapon components were severely mangled or charred but identifiable and accounted for except for the tailfins. The weapon afterbody was ripped from the forward case and rolled into a ball. There was no visible breakage to the squash (the weapon secondary) or blast shield. Intense heat melted the pit, causing it to settle and harden in the case, which was radiating five milliroentgens per hour. The capsule was intact and appeared to be only slightly damaged by the fire. The remains of the bomb were picked up and taken to a munitions storage area by 3:00 PM on the 11th; they were later transferred to the Army Ammunition Plant in Burlington, Iowa for disassembly and disposal. No significant contamination or cleanup problems were encountered.

Chuck Hansen, “The Swords of Armageddon,” Vol. VII, p.244

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12 October

1965 – C-124 / Wright-Patterson AFB, near Dayton, Ohio

At approximately 1:00 AM CDT, a C-124 assigned to Warner Robins AFB near Macon, Georgia was being refueled in preparation for a routine logistics mission when a refueling hose was inadvertently disconnected and a fire started by a spark and fed by 200 gallons of gasoline ensued at the aft end of the refueling tanker truck. The magnesium alloy aluminum fuselage of the aircraft, containing only components of nuclear weapons including two neutron generators, two tritium reservoirs, and 16 MK 43 Mod 0/1 conversion kits and a dummy MK 53 weapon training unit, was destroyed by fire and the refueling truck was heavily damaged. Only the aircraft wings and landing gear remained intact; firefighters prevented gasoline in the wing tanks from igniting. Another 140 neutron generators aboard the aircraft were recovered undamaged, along with three flatbed truck loads of charred containers containing tritium reservoirs.

Base personnel, including firefighters, were not immediately aware that nuclear weapon components were aboard the aircraft. The fire was fought for three hours; water used for firefighting ran off through sewers to the Mad River, a Dayton city drinking water source, near the airbase. The aircrew was unhurt.

There were no casualties and the resultant radiation hazard was minimal. Minor tritium contamination below hazardous levels was found on the aircraft, cargo, and clothing of explosive ordnance disposal and fire-fighting personnel, and was removed by normal cleaning. The C-124's cargo was originally reported to be a limited quantity of conventional ammunition and this information was released to news media. Later it was discovered that the aircraft was also transporting an air shipment of non-explosive nuclear weapons systems components.

Chuck Hansen, “The Swords of Armageddon,” Vol. VII, pp.277-278.

 

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13 - 14 October

No reported incidents.

 

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15 October

1959 – B-52 & KC-135 / Hardinsburg, Kentucky

A B-52 departed Columbus AFB, near Columbus, Mississippi, on a SAC airborne alert mission at 2:30 PM CST and assumed the #2 position in a flight of two aircraft. The KC-135 departed Columbus AFB at 5:33 PM CST as the #2 tanker in a flight of two scheduled to refuel the B-52s. The four aircraft rendezvoused for refueling near Hardinsburg, Kentucky at 32,000 feet. It was after dark, the weather was clear, and there was no turbulence.

Shortly after the #2 B-52 began refueling from its KC-135 tanker, the two aircraft collided about 12 miles south of Hardinsburg. The instructor pilot and pilot of the B-52 ejected, followed by the electronic warfare officer and the radar navigator; these crewmen sustained minor injuries. The copilot, navigator, instructor navigator, and tail gunner failed to leave the B-52 and were killed. The four-man crew of the tanker was killed. The KC-135 broke into two pieces and crashed; the two pieces were on the ground about a mile apart.

The B-52 crashed in essentially one piece at a distance of about three miles from the KC-135 wreckage. The bomber landed at the edge of a wooded area on the side of a small hill and then burned. The tail section was broken off the aircraft just behind the rear landing gear and remained in relatively large pieces. One section of the aft fuselage approximately eight to ten feet long remained intact. Trees were burned for a radius of about 100 yards; the bomber wreckage burned all night and into the following morning.

Only ashes of the forward fuselage, wings, and cockpit were found. Three bodies were found amidst the cockpit residue and the body of the tail gunner was found some distance away on the hillside where he had been thrown upon impact.

Two unarmed gas-boosted, sealed-pit thermonuclear bombs aboard the B-52 were recovered relatively intact after having landed in moist, spongy clay soil which absorbed much of their impact shock. Little or no burning occurred around the weapons despite the presence of a large fuel tank directly above the bomb bay; most of the jet fuel was thrown forward when the fuselage ruptured on impact. Burning was spotty aft of the forward landing gear wheel well and there was little fire in the tail section.

One weapon had been partially burned but this did not result in the explosion of its HE or in the dispersal of any nuclear material or other contamination. The HE in both weapons was shattered and dispersed; the forward case sections of both bombs were intact and unmarred by fire and were found buried nose-down approximately two-thirds of their length in the dirt in the same relative positions which they occupied in the aircraft an about six feet apart. The afterbodies of both weapons were torn off and found a short distance away. The tritium bottles for both weapons were recovered sealed and intact, along with spare detonators. Detonators on the weapons had been ripped loose and loose pieces of HE were evident at every opening in the weapon casings. The pit in each weapon was found lying loose on a pile of broken explosives.
The bombs were later returned to the AEC's Clarksville, Tennessee storage site for inspection and final disposition. There was no radiation detected above normal background level.

Chuck Hansen, “The Swords of Armageddon,” Vol. VII, pp.257-258.

 

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16 - 17 October

No reported incidents.

 

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18 October

1960 – Nuclear bomb / Lake Mead Base, Nevada

Serious damage was inflicted to an aircraft bomb while cycling its automatic in-flight insertion mechanism. When an electrical connector was sheared off, the core charge was scored and gouged, and the sleeve of the HE charge where the core charge fitted was gouged, resulting in a quarter-teaspoon of powdered HE being scraped off.

Chuck Hansen, “The Swords of Armageddon,” Vol. VII, p.262.

 

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19 October

1961 - JUPITER missile / Italy

A JUPITER missile armed with a W-49 warhead was struck by lightning, resulting in deuterium-tritium boosting gas being injected into the warhead pit and activation of thermal batteries in the adaption kit. The missile was returned to operational status after 76 days. On November 4, 1961 the warhead was flown back to the AEC’s Clarksville Modification Center for post-mortem examination.

Chuck Hansen, “The Swords of Armageddon,” Vol. VII, p.268.

 

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20 - 28 October

No reported incidents.

 

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29 October

1952 – Tractor-trailer / Kansas City, Missouri

A fire destroyed a tractor-trailer en route from Oak Ridge to the Bendix weapons component facility in Kansas City; the trailer was carrying a number of Type "D" uranium sphere bomb pits. Several kilograms of U-235 were destroyed. The fire followed a collision between the truck and two passenger vehicles east of Kansas City, Missouri.

Only three intact but badly distorted parts were recovered after the fire. Other items salvaged included halves of spheres and approximately 125 barrels of residue containing uranium oxide which was scraped up from an area immediately adjacent to the truck hulk. Value of the shipment was approximately $200,000; some uranium was later recovered from the oxidized material.

The AEC issued a press release stating that an AEC truck, carrying waste material to Bendix, was involved in the accident. (Not a "Broken Arrow".)

Chuck Hansen, “The Swords of Armageddon,” Vol. VII, pp.239-240.

 

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30 - 31 October

No reported incidents.

 

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Unknown date November

1961 – SUBROC test vehicle / Off Florida

During a flight drop test run, a JATO-boosted SUBROC test vehicle carrying an Operational Suitability Test warhead was lost. Mathematical estimates indicated that the vehicle, which had been accelerated to a velocity of about 900 feet per second by the JATO booster, may have penetrated over 60 feet into the ocean floor. The test firings were being conducted by the Sandia Corporation, Lawrence Livermore Laboratory, and the U.S. Naval Ordnance Laboratory Test Facility at Fort Lauderdale, Florida.

Extensive recovery operations were conducted by the Naval Ordnance Laboratory; recovery efforts resulted in a hole 200 feet long, 60 feet wide, and 22 feet deep at its apex. No portion of the vehicle was recovered, even though the exact point of entry into the seabed was found. Excavation was hampered by drifting sand and hard coral; the ocean floor consisted of 15 feet of sand atop coral boulders. Water in the area was 50 feet deep.

The recovery operation, which began in late November 1961, was curtailed in June 1962 after $45,000 had been spent. The materials in the lost OST warhead included depleted uranium and less than an ounce of high explosives. There were no special nuclear materials in the unit.

Chuck Hansen, “The Swords of Armageddon,” Vol. VII, p.269.

 

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2 November

1961 (date approximate) – Railroad Accident / Location unknown

A letter dated November 13, 1961 from Brig. Gen. A. W. Betts, Director of Military Application, USAEC, to James T. Ramey, Executive Director, Joint Committee on Atomic Energy, refers to a railroad accident on an unspecified date on or before November 2, 1961 involving AEC material. Damage to the AEC caboose and cargo car consisted mainly of broken couplers and steam lines; the unspecified AEC material in the cargo car was reportedly not damaged. One AEC courier escorting the shipment suffered an injury to one of his arms.

Chuck Hansen, “The Swords of Armageddon,” Vol. VII, p.268.

1981 - POSEIDON SLBM / Holy Loch, Scotland

A POSEIDON missile was dropped 17 feet during its removal from submarine tender U.S.S. HOLLAND (AS-32) after a crane operator made an error. The missile's fall was arrested by a safety device, and there was no explosion. The missile's W-68 warhead contained relatively-unstable LX-09 HE, samples of which had detonated during laboratory impact tests. (Not a "Broken Arrow" incident.)

Chuck Hansen, “The Swords of Armageddon,” Vol. VII, p.291.

 

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3 November

No reported incidents.

 

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4 November

1958 – B-47 / Dyess AFB, near Abilene, Texas

A B-47 caught fire on takeoff. Three crewmen ejected successfully; one was killed when the aircraft crashed from an altitude of 1,500 feet. One sealed pit nuclear weapon containing no plutonium and some tritium was aboard the plane; the resultant detonation of its primary HE made a crater 35 feet in diameter and six feet deep. There was some local tritium contamination. The weapon secondary was recovered intact but damaged near the crash site; the weapon case was destroyed. The tritium reservoir was found intact but leaking. The impact crater contained many small fragments of bomb casing, but no HE, which was believed to have been consumed by either explosion or fire.

Chuck Hansen, “The Swords of Armageddon,” Vol. VII, pp.251-252.

 

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5 November

No reported incidents.

 

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6 November

1961 - W-47 pit / Pantex Ordnance Plant, Amarillo, Texas

During the disassembly of an early model W-47 warhead, the pit fill tube used to supply pressurized D-T gas to the pit during arming ruptured, permitting the helium inside the pit to escape (the pit was kept filled with helium to detect leaks during storage). The helium gas was contaminated by the radioactive plutonium in the pit. Three men working in the area heard the “hissing” caused by the escaping helium gas and immediately evacuated the area. Two men working on the pit were wearing respirators; all three men washed off some contamination on their skin and clothing. Three days were required to decontaminate the removable MK 47 tooling and another one to two weeks were required to decontaminate the accident area.

The U.S. Army Ordnance Corps representative at Pantex made the following announcement to the news media:

“Three Mason and Hanger-Silas Mason Co., Inc. employees were involved in a minor radiation incident on November 6 at the Pantex Ordnance Plant near Amarillo, Texas. The incident occurred during a routine operation involving radioactive materials. Medical examination of the three men, who have not lost any work time as a result of the incident, will be continued as a routine matter. There was no escape of radiation into the atmosphere.”

Chuck Hansen, “The Swords of Armageddon,” Vol. VII, pp.268-269.