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Historical Series

35th Munitions Maintenance Squadron

Nuclear Weapons Maintenance- The Early Year's

Biggs AFB, Texas March 1956-July 1959

I arrived at my first Strategic Air Command (SAC) base, Biggs AFB, El Paso, Texas, in March 1956 after completing six months of Technical School at Lowry AFB, CO as a Nuclear Specialist (AFSC 332X0). The Munitions Maintenance Squadron (MMS) had not been established yet and all the Munitions personnel (AFSC 331X0, 332X0, 461X0, 462X0, 463X0, and 464X0) were assigned to the 810th Supply Squadron until the 35th MMS was activated in early 1957. For the first few months everyone in SAC worked a 5 1/2 day week (or more) which was down from a 6 day work week only a few months before. For most of us getting to and from work meant riding in the back of a 2 1/2 ton truck to the other side of the runway where our temporary area was located.
In 1956, the Atomic Energy Commission (AEC) began releasing nuclear weapons for storage on SAC bases under the "Bombs on Base" (BOB) concept. However, the Weapons Storage Area (WSA) at Biggs was still under construction when I arrived, and only Mark 6 and Mark 15 training weapons were on base. Until the completion of the WSA, approximately 3 months later, we worked in a temporary "Butler" building complete with an outhouse. When completed, the WSA area consisted of the Security Police Building (cop shack), Emergency Power Building, 39D Warehouse, Maintenance and Inspection (M&I) building, 2 storage structures containing large vaults for nuclear components (capsules) and a number of igloo's for weapon storage. The M&I building had two mechanical bays separated by an electrical bay, plus an office, breakroom, stockroom, bathroom, and a battery room. The approximately 25 personnel assigned to the M&I building consisted of a mix of AFSC's made up of 331's (Electrical), 332's (Nuclear), and 463's (Mechanical).
As soon as the WSA was completed and turned over to the Air Force, we began receiving war reserve (WR) nuclear weapons and security was stepped up. Everyone was issued a flight line badge (with picture and access data) which was required for access to the flight line. The Security Police constantly patrolled the area in pickup trucks and with an armored car equipped with a .30 caliber machine gun. Each Security Policeman was armed with a.45 caliber pistol and a .30 caliber carbine, however they had access to .45 caliber "Tommy guns", .30 caliber machine guns, and 60mm mortars which were stored in the Gate Shack. After duty hours and on weekends, guard dogs and their handlers also patrolled the area on foot.
Access to the M&I building and the igloos was strictly controlled. For a few months after the arrival of the weapons on base there were two AEC representatives assigned to the organization who were responsible for one set of igloo keys and they were the only two persons who had the combination to one of the safes. If it became necessary to enter an igloo after normal duy hours we would have to call the AEC representative that was on stand-by and wait for him to drive from downtown.
The aircraft assigned to Biggs were 30 B-36's, 45 B-47's, plus a number of KB-50's, KC-97's, C-45's, C-54's, C-119's, C-124's, T-33's as well as B-26's, B-45's, and B-57's which were used to tow targets for the Army's Fort Bliss anti-aircraft training center. Having this large number of bomber aircraft (75) assignd it was necessary to also have a large number and assortment of weapons available on base. These weapons were:

Weapon       Type     Width       Length     Weight          Yield
Mk 6           fission     61"           128"       8,000 lbs       80, 154-160 Kt
Mk 15         fusion      35"           140"       7,600 lbs       3.8 Mt
Mk 17         fusion      61"           296"       42,000 lbs      11 Mt
Mk 21         fusion      58"           150"       16,000 lbs      4.5 Mt
Mk 36         fusion      58"           150"       17,600 lbs      10 Mt
                                           Source- "U.S. Nuclear Weapons" by Chuck Hansen

The B-36 was a massive aircraft and could carry, in theory, 4 nuclear weapons however in most cases only one large weapon, a Mk 17, Mk 21, or Mk 36 or two smaller weapons, Mk 6's, were carried with the remaining bomb bays being filled with fuel tanks. The B-47, having only one bomb bay, could carry one Mk 6, Mk 15, Mk 21, or Mk 36. Of course the Mk 21 or Mk 36, being heavier than the Mk 6 or Mk 15, considerably shortened the effective range of the B-47.
The early weapons required very detailed maintenance such as receipt inspections, final assembly test, prep for strike, etc. Receipt inspections on the Mk 6 Mod 6 involved removing the two batteries, the weapon side panels, rear cover, dets, and fuse. An electrial test of each det was required before re-installation. The fuse was mounted on rails and accessed through the back of the case. It was unbolted and rolled on to small trailer and then taken into the Electrical Bay where the baro's, motor generators, and firing circuits were tested and any faulty items replaced. The batteries were removed from the weapon and taken to the Battery Room for service and storage. A visual inspection of the pit was also performed at this time. Following these inspections the dets, fuse, and side panels were reinstalled, all seams and baro ports were covered with lead foil tape, dessicant was installed in the rear case and the cover installed; the Mk 15, 17, 21 and 36 required similar inspections, other than the det inspection.
The batteries were nickel cadmium, contained a
number of cells, and required a lot of maintenance. All
batteries had to be discharged, topped off with water,
recharged, and load tested at regular intervals. This kept
one 331 busy at all times since enough batteries had to
be maintained at full charge to meet the EWO generation
schedule. Prior to installation into the weapon each
battery was placed in an insulated and heated battery
box. This was done to prevent the battery from losing a
percentage of it's charge due to prolonged exposure to
sub-zero temps during flight.
In order to keep all personnel well trained a base recall
and practice exercise was held each month. This
involved every weapon on the EWO being brought
through the M&I and being placed in strike configuration.
With the Mk 6 the batteries were installed, the dessicant was removed from the rear of the case, the tape removed from the baro ports, and a final assembly test was run. The Mk 15, 17, 21, and 36 were parachute retarded and the fuse, and IFI tube on these weapons was accessed through the rear case after the parachute was removed. As I remember, the prep for strike on the Mk 15, 17, 21, and 36 required the installation of the batteries, baro port tape removal, and final assembly test. In the case of an actual EWO a capsule was installed in the IFI tube prior to parachute installation and the weapon leaving the M&I building. This only happened once, except for weapons going on alert aircraft, during my stay at Biggs and that was during the Middle East War of 1956 (Suez Crises). These prep for strike preparations took 1-2 hours per weapon and it sometimes took 2 or 3 days to process all the required weapons. Once the weapons were prepped for strike a convoy was formed and the weapons delivered to the flight line for loading aboard an aircraft. There was no time limit to the number of hours personnel could work; we worked until all the weapons were prepped.
When the practice exercise was over all the weapons would again have to be receipt inspected. This would take the better part of the next month and would be completed just in time for the next exercise. We almost wore those weapons out inspecting them.
There was always a number of fully loaded B-36 and B-47 aircraft on 15 minute alert. This, of course, meant we had a steady flow of weapons being prepped for strike and being loaded on an alert aircraft. The Mk 15, 17, 21, and 36 required a capsule to be installed in the IFI tube.. When the aircraft came off alert the Mk 15, 17, 21, and 36 would have the parachute, capsule, batteries, and fuse removed, tested, and reinstalled and the weapon returned to storage. The Mk 6 required a full receipt inspection. All this had to be worked into the inspection of the weapons that had been used during the last practice exercise.
The Mk 6 was stored on a roadable trailer which had four balloon tires. This enabled the Mk 6 to be towed behind a warehouse tug or truck for short distances such as from the igloos to the M&I building or to the flight line. The Mk 15, 21, and 36 were stored on bolsters, which had four pairs of fiber wheels while the Mk 17 had eight pairs of fiber wheels. These units could be towed very short distances and required a straddle carrier in order to be moved to the M&I building or to the flight line. Since the weapon shape was classified all weapons were surrounded by a frame and covered with a rubberized security cover while being moved or in storage. During loading operations the aircraft bomb bay was surrounded by a security curtain and the weapon was rolled inside the curtain before the weapon security cover could be removed.

Due to the weight of the Mk 17 (42,000 lbs) it posed special handling problems. A warehouse tug was used to move the weapon in or out of the igloos and M&I building. However, if one of the bolster's wheels came to a stop on an expansion joint in the floor the tug could no longer move the weapon; the tug's wheels would simply spin. In order to get the weapon moving it was necessary to place a jack under the bolster next to the stuck wheels, raise the bolster slightly and then pull the weapon off the jack. This resulted in a very large earthshaking thud and the occasional ruined jack. After a few month's steel rails were imbeded in the igloo floors for the bolster wheels to ride on thereby eliminating the problem in the igloos; however, we still had to be careful where we stopped the weapon in the M&I building. The Mk 17 was so huge the hoists in the M&I building could not lift the entire weapon, only the nosecap, afterbody, and parachute. This made inspection of the bolster and under side of the weapon very difficult.
With the scheduled retirement of the B-36, which was the only aircraft that could carry it for any effective distance and with it's somewhat crude design, the AEC began retireing the Mk 17 in August 1956. Starting in early 1957 the Mk 17's at Biggs were prepped for ferry, loaded into a B-36 and flown to Kirtland AFB, NM to be demilitarized. It was one of the Mk 17's from Biggs that fell through the bomb bay doors of a B-36 over Kirtland AFB in May 1957. This resulted in the total destruction of the Mk 17 and while the B-36 was able to safely land it had to be salvaged due to the airframe being badly damaged.
We had another incident at Biggs of a B-47 releasing a training weapon in flight. Both B-36's and B-47's frequently flew with a training (dummy) unit aboard to get the flight crews acquanted with aircraft handling while carrying a heavy weapon. This particular B-47, carrying a Mk 15 training shape, was on a landing approach when the crew received a "Fire in the Bomb Bay" indication. Not realizing the training weapon contained no high explosives the crew jettisoned the weapon from an altitude of 1,500 feet and a quarter of a mile from the end of the runway. The parachute on the training wapon did not have time to fully deploy before weapon impact, at an approximate 30 degree angle in very hard west Texas soil. The impact buried the nose of the training weapon and bent the 6 inch thick case into a swayback shape. As it turned out the B-47 had no fire and landed safely.

Trained as a Nuclear Specialist (AFSC 332X0) my job was to inspect and maintain the nuclear components (capsule and pit) of the weapons. We were trained on how to disassemble the capsule and inspect the initiator but by the time I reached the field it was no longer necessary to perform this function. We were, however, still required to inspect the exterior of the capsule.
The capsules were stored in an igloo containing a large bank type vault having two combination locks. Entering this structure required two persons, after entering the igloo and vault the birdcage containing the capsule to be inspected was removed to an inspection area outside the vault. Prior to opening the birdcage it was necessary to put on protective gear consisting of a rubberized apron, respirator, and latex gloves. The birdcage was pressurized and dessicated so the first step was to release the pressure and remove the top. A handling tool was screwed into the base of the capsule support. The capsule was removed from the birdcage, and placed in a support ring on the worktable. The capsule and support was then visually inspected and cleaned using Kimwipes and trichloroethane. As the capsules aged and went through temperature changes they would begin to spall. Spalling was a condition that resulted in small particles of radiactive material popping off the surface of the capsule, sometimes as far as two feet. If the capsule was spalling there was a transparent plastic cover, with two hand holes, that was hurriedly placed over it. Even so, radioactive particles would always end up on the floor and table. Cleanup of the particles involved wiping and/or painting the affected area. After inspection the capsule was returned to the birdcage, a bag of dessicant was placed on the support, the top was replaced, and the birdcage was pressurized using a pump much like an old style bicycle pump. At the end of the workday the inspection area and all personnel were checked for traces of radiation.
Pit inspections were done in the Mechanical Bay using latex gloves, flashlight, mirror, Kimwipes, and tricloroethane. A visual inspection was conducted with the flashlight and mirror by looking through the IFI tube. The pit was then wiped down with Kimwipes and triclor. The difficult part was trying to reach the back of the pit, in the Mk 6 your entire arm was inside the pit and your head was pressed against the HE sphere and a det. In the Mk 15, 17, 21, and 36 it was necessary to reach through the IFI tube and in order to clean the back of the pit we used a toilet brush wrapped with a Kimwipe.
We were aware that the weapons and capsules emitted radiation, but we were told the levels were acceptable and most of us gave it no thought. In the begnning we each carried a film badge that was read once a week to see how much radiation we had been receiving. After a few months the film badges were replaced by dosimeters which were read every six months. We were never told how much radiation we were receiving.
Capsule and pit inspections did not keep the three 332X0's assigned busy all day so we were cross trained as 331X0's to inspect and test the weapon fuses. Whenever a fuse was brought into the Electrical Bay the first step was to perform the baro switch test using the T-1B Tester which was connected to the baro to be tested by vacuum lines and electrical cables. The altitude the baro switch was to close was set and the vacuum pump started. It was then a matter of watching the altimeter until an indicated altitude of 45,000 feet was reached. At that time the vacuum was slowly released and the point where the baro closed was monitored. This procedure was repeated three times for each of the two baros the fuse contained and took approximately 45 minutes per fuse.

The fuse was then moved to the motor generator test station where each of the two motor generators was run, and the capacitor bank was charged and discharged. during this test the output of the motor generators and the charging and discharge time of the capaciter bank was checked. If a defective baro or motor generator was found a replacement item was pulled from spares and the defective item replaced and appropriate test was run. Total time for a fuze was approximately two hours.
In 1957, sealed pit weapons were introduced effectively putting 332's out of a job although pit inspections were still required on "open pit" weapons. In late 1957, in response to the reduced requirement to inspect nuclear components, the Air Force converted most 332's to 33150's. In order to meet the requirement for pit inspections "Inspection of Nuclear Components" was included in the 331X0 job description.
In early 1959 the last B-36 aircraft was retired and all other aircraft were transferred from Biggs AFB while the runway was rebuilt and lengthened to accept B-52's. In July 1959, shortly before the first B-52 was scheduled to arrive, I was transferred to the 702nd Strategic Missile Wing (ICM-Snark) at Presque Isle AFB, Maine.

Mk 6 bomb (National Atomic Museum). IFI was performed manually.

Mk 15 on H-508 Bomb Trailer

Mk 17 drop shape recovered at Edwards AFB, CA (USAF)

Mk 21 thermonuclear bomb. The Mk 36 was a 1957 modification of the Mk 21 (Hansen, U.S. Nuclear Weapons, 156).

Straddle Carrier for the Mk17