This day in US nuclear accidents

[mhansen2]

25 - 30 January

No reported incidents.

 

[mhansen2]

31 January

1958 – B-47 / Sidi Slimane, French Morocco ("SAC REFLEX Base")

A B-47 with one weapon in full strike configuration with safing pins installed in the pullout switch, arm/safe switch safed, baros set, and U-2 rack unlocked, was making a simulated takeoff during an exercise alert. When the aircraft reached a taxi speed of approximately 30 knots on the runway, the left rear wheel casting failed. The aircraft’s tail struck the runway; the plane broke in two and a fuel tank ruptured, spilling JP fuel over the weapon and surrounding area.

The aircraft caught fire and burned for seven hours; crash trucks arrived within three minutes and sprayed foam over the wreckage. Firemen fought the fire for the allotted ten minutes fire-fighting time for HE contents of the weapon, then evacuated the airbase in the erroneous belief that a nuclear explosion was imminent. The HE in the bomb did not detonate, but there were varying levels of alpha particle contamination in the immediate area of the crash. Rescue crews bulldozed wreckage to the side of runway, leaving weapon parts exposed. After the wreckage and the asphalt runway paving beneath it were removed and the runway washed down, no contamination was detected; however, the wreckage was highly contaminated by plutonium.

The intensive heat of the aircraft fire melted the capsule and a large part of the weapon. A portion of the squash (weapon secondary) was found intact and fissionable capsule material was detected in slabs of other molten metals. The fire created a slab of slag material weighing approximately 8,000 lbs.; this slab was approximately six to eight feet wide and 12 to 15 feet long with a thickness of 10 to 12 inches. Weapon components and miscellaneous aircraft components were intermingled within the slab. Heavily contaminated pieces of this slab were broken out with jackhammers and segregated and packaged into sealed cans.

All residue not identified as aircraft parts was moved by truck to an ammunition storage area. The revetment where debris packaging took place was leveled by a bulldozer and all remaining debris was covered by three feet of dirt. One fire truck and one fireman's clothing showed slight alpha contamination until washed. A large number of people and vehicles were contaminated with plutonium and smoke-carried fallout drifted as far as 40 miles, contaminating a local naval base. Fallout was also detected at other locations in Morocco even further away.

Subsequent inspection of the weapon involved in this incident revealed that the afterbody and approximately one-half of the warhead case were melted and unrecognizable; there was evidence of very high gamma ray and alpha particle radiation from remnants of the melted afterbody. Inspection of the weapon sling and U-2 lock indicated that the weapon had not separated from its rack. Remains of the weapon's detonators showed that they, as well as the HE, had burned but had not detonated. The residue of the weapon and capsule was returned to the U.S. on February 27 where it was subsequently buried.

Following the accident, exercise alerts were temporarily suspended and B-47 wheels were checked for defects.

Chuck Hansen, “The Swords of Armageddon,” Vol. VII, pp.246-247.

 

[fncceo]

Jan 29, 1964.

 

[mhansen2]

Unknown date in February

1958

During February 1958, an aircraft crashed “on base” while carrying a MK 7 training weapon. Aircraft wreckage was mingled with weapon parts over an area approximately 250 feet wide by 0.25 miles long. The aircraft impacted in a relatively flat attitude, so the weapon did not penetrate the ground but instead tore loose from the aircraft. The largest piece of the weapon recovered was a part of the tail section. Separation of weapon skin and components from aircraft wreckage was difficult; several parts were partially covered by drifting sands.

Chuck Hansen, “The Swords of Armageddon,” Vol. VII, p.248.

 

[mhansen2]

1 - 4 February

No reported incidents.

 

[mhansen2]

5 February

1958 – B-47 / Savannah River, Georgia

A B-47 carrying an unarmed MK 15 Mod 0 War Reserve weapon was on a unit simulated combat mission maneuver that originated at Homestead AFB, Florida. While near Sylvania, Georgia the aircraft had a mid-air collision at an altitude of 30,000 feet with an F-86 aircraft involved in a simulated attack at approximately 2:00 AM. Following the collision, the B-47 made three attempts to land at Hunter AFB, near Savannah, with the weapon aboard. The F-86 crashed after its pilot ejected safely.

Because of damage sustained by the bomber, its airspeed could not be reduced enough to insure a safe landing and the crew decided to jettison the bomb rather than expose Hunter AFB to the possibility of an HE detonation. A nuclear explosion was impossible because the nuclear capsule was not installed in the weapon; however, the bomb contained at least 400 lbs. of HE around its primary.

The weapon was jettisoned into water five miles southeast of the mouth of the Savannah River (Georgia) in Wassaw Sound off Tybee Beach in Chatham county. The precise weapon impact point was unknown; however, the best estimate was at a position of 31D 54M 15S N, 80D 54M 45S W, approximately 15 statute miles east-southeast of Hunter AFB. The bomb was dropped from an altitude of approximately 7,200 feet at an airspeed of 180 to 190 knots; no detonation occurred and the bomb was assumed to have shattered on impact. The river was approximately 100 feet deep where the weapon landed.

After jettisoning the weapon, the B-47 landed safely at Hunter AFB. During a subsequent nine-week period, a three square mile area, with water depths ranging from 6 to 30 feet, was searched by at least 11 Navy and Coast Guard boats and ships, including a ship with divers and underwater demolition team technicians using galvanic drag and hand-held sonar devices. The weapon was not found and the search was terminated on April 16, 1958. This accident, including the weapon loss, was released to the press.

The bomb was considered irretrievably lost, either buried under mud on the seabed or disintegrated on impact. On June 10, 1958, the Department of Defense requested the AEC to transfer a new weapon to stockpile to replace the lost bomb. Since there was a possibility of accidental discovery of the unrecovered portion of the bomb through dredging or construction in the probable impact area, DOD monitored all activities in the vicinity of the lost bomb.

During the summer of 2000, acting at the request of a local congressman, the Air Force, DOE, and the Navy re-examined the possibility of attempting to retrieve the lost bomb. After examining arguments both in favor of and opposing the effort, the Air Force concluded that the bomb — if still intact — was probably buried at a depth of five to 15 feet in the riverbed silt and that no recovery should be attempted.

Chuck Hansen, “The Swords of Armageddon,” Vol. VII, pp.248-249.

 

[mhansen2]

6 - 7 February

No reported incidents.

 

[mhansen2]

8 February

1958 - B-52 / Ellsworth AFB, near Rapid City, South Dakota

A ground accident occurred at Ellsworth when a nuclear weapon was inadvertently dropped from a B-52D bomber parked at a pad and ready to be unloaded. Preliminary reports indicated that an airman erred and pulled the manual release handle which released the weapon from the bomb bay and through the unopened bomb bay doors.

Damage to the weapon included a dented afterbody, two smashed fins, and a displaced secondary. There was no capsule aboard the aircraft. The bomb was loaded aboard a trailer and removed to a weapons maintenance depot at Rushmore AFB, South Dakota. The damaged weapon was later exchanged for an operational weapon from stockpile.

Chuck Hansen, “The Swords of Armageddon,” Vol. VII, p.249.

 

[mhansen2]

9 February

No reported incidents.

 

[mhansen2]

10 February

1960 – Railroad train / AEC storage site, Clarksville, Tennessee

At 10:45 AM EST, while being switched at a railroad siding, five ATMX cars carrying MK 31 weapons broke loose, ran down a 2% grade, and hit a bumper. One car was derailed but remained upright. There was no damage to the weapons. No news release was issued.

Chuck Hansen, “The Swords of Armageddon,” Vol. VII, p.258.

 

[mhansen2]

11 February

1950 - Beech D-18 / Albuquerque, New Mexico

A twin-engine Beechcraft D-18 cargo air service aircraft flying from Dayton, Ohio to Albuquerque crashed four miles west of West Mesa Airport with a pilot and two AEC security guards aboard. The plane was making an approach to a landing strip when it encountered a cloud and broke off the approach. While circling around the mesa atop which the airstrip was located, the plane hit a steep slope and crashed in an upright position.

The plane was completely demolished by the ensuing impact and fire, killing all three men aboard. The classified cargo of 792 HE detonator units in 22 boxes was destroyed and was salvaged from the wreckage. Since there was no evidence of sabotage, and since none of the detonators appeared to be missing, the incident was not reported to the Federal Bureau of Investigation.

Chuck Hansen, “The Swords of Armageddon,” Vol. VII, p.235.

 

[mhansen2]

12 February

No reported incidents.

 

[kaz]

13 December

1960 – Naval Ordnance Test Station, San Clemente Island, California

At approximately 7:45 PM PST, an explosion occurred in a storage bunker at the Naval Ordnance Test Station (NOTS) on San Clemente Island, approximately 40 miles west of San Diego, California. Two "development type" nuclear warheads were in the bunker at the time of the explosion; the warheads contained "toxic materials" but no high explosives. One of the warheads was damaged by flames. The explosion originated in a Jet-Assisted Take Off (JATO) rocket which was being prepared for mating to one of the developmental warheads in preparation for a test. The explosion resulted in one fatality and three additional casualties; all were NOTS personnel. No AEC news release was issued.

Chuck Hansen, “The Swords of Armageddon,” Vol. VII, pp.262-263.

For the source material, go here:

index.htm

So you think that threats to America should be treated by the standard of 1960? Of course you do, Hugo Chavez ...

 

[mhansen2]

So you think that threats to America should be treated by the standard of 1960? Of course you do, Hugo Chavez ...

I don't know what you're talking about.

 

[mhansen2]

13 February

1950 – B-36B / Pacific Ocean, off British Columbia coast

A B-36B (44-92075) was en route from Eielson AFB near Fairbanks, Alaska, to Carswell AFB in Fort Worth, Texas on a simulated night high-altitude combat profile mission (target: San Francisco) with a simulated combat load; a MK 4 nuclear weapon aboard the aircraft had a dummy capsule installed. After about six hours of flight, the aircraft's numbers 1, 2, and 5 engines caught fire from severe carburetor chamber icing which caused back-firing. The burning engines were feathered and shut down at an altitude of 12,000 feet.

Severe rime icing conditions complicated the emergency and level flight and constant altitude could not be maintained. Following instructions from an Air Force base, the aircraft headed out over the Pacific Ocean, armed the weapon, and dropped it from 8,000 feet. The bomb's high explosives detonated at an altitude of 3,800 feet, resulting in a bright flash followed by sound and shock waves.

The aircraft was then flown east over Princess Royal Island, 120 miles southeast of Prince Rupert, British Columbia, and 50 miles from the town of Bella Bella, on Hunter Island to the south, where the sixteen crewmen and one passenger bailed out at an altitude of 5,000 feet while the aircraft was on a heading of 165 degrees and losing altitude at a rate of 100 feet per minute.

Twelve aircrewmen were eventually rescued from Princess Royal Island and five persons were still missing by May 1951. An accompanying B-36 continued onto Carswell AFB. At the time of the accident, no mention was made of the nature of the aircraft's bomb load.

The aircraft wreckage was not located until September 1953, when it was found at an altitude of 6,000 feet in the Skeena Mountains east of Meziadin Lake on the east side of the Nass River valley east of the town of Stewart in northwestern British Columbia (crash site coordinates were 128D 32M W, 56D 3M N).

After the crew bailed out, the aircraft apparently gained altitude, turned nearly 180 degrees, flew north for nearly three hours (a continuous radio signal from the aircraft was detected at Eielson AFB), covered a distance of 210 miles over terrain 6,000 to 8,000 feet high, and finally crashed at an altitude of 6,000 feet. After a salvage team recovered some items, the crash site was “erased” with explosives, although substantial wreckage remained even as recently as 1998.

Chuck Hansen, “The Swords of Armageddon,” Vol. VII, p.235.

 

[mhansen2]

14 February

1974 - FB-111 / Plattsburgh AFB, New York

At approximately 11:00 AM, the nose landing gear of a USAF FB-111 collapsed as the aircraft was undergoing an engine run-up during a normal alert exercise. The aircraft was loaded with two SRAM air-to-surface missiles and two nuclear bombs. There was no damage to the weapons and they were unloaded without incident.

Normal emergency precautions were taken on and around the airbase. A portion of a nearby public highway was closed; a "fuel spill" was given as the reason for the closure.

Chuck Hansen, “The Swords of Armageddon,” Vol. VII, p.289.

 

[mhansen2]

15 - 21 February

No reported incidents.

 

[mhansen2]

22 February

1970 - PERSHING IA missile / Boettingen, West Germany

On the morning of February 22, an Army missile crew was instructed to replace a bent heat shield covering the guidance and control section splice band on a PERSHING IA missile at a Combat Alert Status site near Boettingen, West Germany in Baden-Wurttemberg province near Stuttgart. A crewman removed the explosive bolt detonating cable from the splice band joining the guidance and control section to the missile warhead section. He then loosened the bolt to which the detonator cable was connected, not realizing that this bolt also held the splice band together.

The loosened bolt allowed separator springs to eject the warhead section forward from the guidance and control sections; the warhead section fell about three feet and struck a work platform on the Improved Erector Launcher (IEL), slid off the platform, and then fell another six feet to the ground (pavement). The warhead section landed on its nose, rolled over and came to rest on its top. The W-50 warhead did not burn or detonate.

The crewman was working alone in violation of the two-man rule requiring no fewer than two persons around nuclear weapons and had not notified his supervisors of his intentions.

Approximately one-half inch of the missile nose cone was broken off; another two inches were gouged. Ablative material on the warhead section was deeply scraped for a distance of nine inches. The launch pad was evacuated and the area sealed off. Explosive bolts on the missile were disconnected and all power to the pad was cut off. Personnel working around the warhead at the time of the incident took decontamination measures and the warhead was later disarmed and replaced. There was no radioactive contamination and no damage other than that to the warhead section. The accident was originally reported as a "Broken Arrow" incident and was later downgraded to a "Bent Spear" incident.

Chuck Hansen, “The Swords of Armageddon,” Vol. VII, p.289.

 

[mhansen2]

23 February

No reported incidents.

 

[mhansen2]

24 February

1956 – C-124 / Over the North Atlantic

Restricted data cargo was jettisoned from a C-124 over the North Atlantic, including nuclear weapon firing and maintenance sets. The cargo was dropped from an altitude of 8,000 to 9,000 feet. The plane was enroute from Goose Bay, Labrador to Upper Heyford in the United Kingdom when it lost power in its number one and four engines. The Air Force assumed that the cargo packaging ruptured and sank after impact with the sea. Although the impact area was searched, nothing was recovered.

On its return flight to the U.S. on March 2, the aircraft crashed in the Atlantic approximately 225 nautical miles southwest of Keflavik, Iceland. The aircraft and crew were lost in 3,000 feet of water.

Chuck Hansen, “The Swords of Armageddon,” Vol. VII, p.240.