Radiation Exposure To Nuclear Weapons Technicians

Updated 3 November 2023



A major source of ionizing radiation that Nuclear Weapons Technicians were exposed to was Intrinsic Radiation, defined as: “Ionizing radiation emitted through the nuclear weapon surface or directly from exposed weapon components.”

Source: U.S. Department of Energy and Defense Threat Reduction Agency (formally Defense Nuclear Agency) 1

One of the primary dangers that affected Nuclear Weapons Technicians was Intrinsic Radiation from the nuclear weapons we maintained, stored, and transported. Generally, Nuclear Weapons Technicians were not made aware of intrinsic radiation, nor informed of the actual dangers from neutron radiation that permeated nuclear weapon exterior cases and also passed through lead shielding.

Thousands of Nuclear Weapons Technicians worked on live nuclear weapons during the Cold War period with no pre-work ionizing radiation bioassays, no ionizing radiation dose monitoring, no established exposure dose measurements, and no radiation exposure limits.

Nuclear Weapons Technicians worked on, in, and in close physical proximity to nuclear weapons without training, requirements or restrictions related to time, distance, and shielding from intrinsic radiation sources, now known as ALARA (As Low As Reasonably Achievable). Specific training and personnel radiation safety requirements and restrictions—unique for each weapon series and configuration—were limited or not otherwise provided.

Most nuclear weapons tasks required direct physical contact. From leaning on and reaching over weapons, to the routine requirement and practice of having our hands, arms, face, and head inside the interior of “open” or disassembled weapons, and with our torso and legs frequently in direct contact with the nuclear weapon exterior surfaces.

B53 Thermonuclear Bomb in the multi-megaton range. First produced in 1962, retired in 1997. Ionizing radiation emitted through the external surface, in every direction. Photo credit: unknown.
MK7 Bomb (warhead without rear section) - Hoisting operation for maintenance tasks on a ship. The MK7 could be carried by Navy and AF aircraft. Photo credit: unknown.

Examples of ionizing radiation exposures (alpha, beta, gamma, and neutron) during routine, accepted, and authorized practices among U.S. military Nuclear Weapons Technicians during the Cold War period include:

  • Nuclear weapons handling, maintenance and repair, disassembly, limited life component exchange, assembly, calibration, status checks, transport, storage, and other tasks.

  • Nuclear Weapons Technicians removed and replaced critical components and radioactive hardware such as bolts, nuts, washers, and clamps. In some weapons, lead foil tape was temporarily placed over holes—where bolts had been removed near the physics package—and later disposed of in the trash. Neutron radiation is known to induce radioactivity in items, however; radioactive components, hardware, tape, cleaning materials, and other expendables were rarely handled or otherwise treated as radioactive materials/hazards.

  • A multi-service technical manual used for all nuclear weapons maintenance stated: “If a vacuum cleaner is used to clean components or areas where there are possible loose radioactive materials, monitor the bag of the cleaner periodically. If found to be contaminated, dispose of the bag in a paper bag labeled “Contaminated Waste”. 2

  • Nuclear Weapons Technicians removed radioactive particles/spalling 3 material by vigorously rubbing the target and target rings for projectiles of gun-type weapons and capsule balls, spheres, cores, etc., for early series of nuclear weapons. This created hazardous conditions for inhalation, and absorption through cuts and abrasions.

  • Alpha particles are known to be 20 times more dangerous (biological damage) than beta and gamma radiation. Nuclear Weapons Technicians were often “dusted” with radioactive particles on their clothing and any unprotected areas of their head, face, etc. (particularly while removing spalling material). Uniforms were brushed off afterward (sometimes vacuumed) with the potential of leaving radioactive particles on clothing to take home to family members, the barracks, quarters, etc. Use of a portable Radiac meter, or similar, to scan the Technician with a wand to “ensure” all particles were removed was often met with skepticism. Nuclear Weapons Technicians stated that the decontamination procedure was typically rushed and not thorough, but few dared to question the conduct of the scans.

  • Nuclear Weapons Technicians reported stacking sandbags between weapons in storage, as some later surmised, to increase weapons safety or allow for additional weapons to be stored in the same space. Many also reported transporting the radioactive capsule components in “bird cages” on every other seat in buses. Some units used a 4-foot rule, center-to-center for weapons, others a 1-meter edge-to-edge rule. These procedures were not for personnel radiation safety; they were for nuclear weapons safety. Those limitations were likely related to studies of separation distances for subcritical units, such as those conducted for a U.S. Atomic Energy Commission contract and documented in a 1962 Lawrence Livermore National Laboratory report: “Interaction of Fissionable Units”. It read in part: “Although each unit, when isolated, may be subcritical by a substantial margin, the assemblage may be critical if the number of units is sufficiently large and if the units are sufficiently close to each other and to neutron-reflecting materials. 4 [emphasis added]


Many Nuclear Weapons Technicians’ tasks varied between multiple nuclear weapon series at the same location. We often worked on one or more of the many different series of warheads, bombs, artillery shells, atomic demolition munitions and associated rockets and missiles on any given day. Weapons widely ranged from 0.x kiloton to multiple megaton weapons depending on the location and mission of the organization. Many of the same weapon series/types were maintained by two or more services. For example, weapons maintained by Air Force units were transferred to, and maintained by, Navy units.

Individual Nuclear Weapons Technicians worked on different series of nuclear weapons at varied intervals, and our exposures depended on what team member “position” was filled for a particular task on a given day. In a typical scenario, it was common for one person to stand adjacent to an open weapon, reading the checklist items and verifying completion of steps, while one or two others “operated” inside the open nuclear weapon. Another managed the tools and parts and inspected, cleaned, and prepped items in preparation for installation. Positions often rotated. Nuclear weapons maintenance supervisors/managers observed and monitored the operations, and quality control inspectors routinely participated.

MK 7 nuclear bomb with related test equipment. Image: Sandia National Lab, Early Nuclear Safety video
Many nuclear weapons required hands, head or entire body to be inside. Image: Sandia National Laboratory, "Early Nuclear Safety" video  

Risks were not properly managed to keep exposures to ionizing radiation ALARA in context with modern-day requirements. Some Naval nuclear propulsion-related ionizing radiation dosimetry activities apparently evolved into limited weapons-related dosimetry programs. Arguably, many were improperly managed. Evidently, few fully-operational nuclear weapons-related ALARA and INRAD programs (which must co-exist to be effective) were established before 1991.

Neither we nor our organizations knew what our actual ionizing radiation doses were; and we generally worked without restrictions in regard to distance, time, or shielding from the radiation sources (aka ALARA). The dangers were compounded by multiple factors as the radiation dose was directly related to the series of nuclear weapon(s) and the operation(s) completed. Primary factors included: assembled/disassembled status; time near, on, or in the weapon; distance; number of nuclear weapons in the same space; and shielding.

Other than limited or questionable Navy dosimetry programs, and few Army and Air Force short term or abbreviated studies or “experiments”, 5 ionizing radiation exposure monitoring and management programs were unique exceptions to the norms. Many Nuclear Weapons Technicians rarely, if ever, wore a dosimeter during their careers. Initial programs with dosimeters were often cut short. Dosimeters were limited, ineffective, and/or inaccurate. Potentially thousands of exposure dose records, such as DD Form 1141 Record of Exposure to Ionizing Radiation, were misplaced, incomplete, error-ridden, falsified, and/or destroyed (in the 1973 National Personnel Records Center fire). 6


Department of Energy and Military Services INRAD Research


Carter-Reagan Transition Briefing Book (U), December 1980, Defense Nuclear Agency 7

“Intrinsic Radiation (INRAD) Study: A growing public awareness of and concern for the hazards of low level, intrinsic radiation inherent in nuclear weapons has been increasing. The number and size of legal claims based upon exposure to alleged radiation has risen sharply. Previous risk estimates were minimal for low level exposure to stored nuclear materials. While the general view remains that the effects are insignificant, DoD has decided to verify a variety of associated aspects. A joint DoD/DoE study has been initiated to review the impact of intrinsic radiation…” to include “Identification of personnel who receive INRAD doses; INRAD output of current stockpile; Evaluation of Service programs, regulations, and procedures; INRAD implications to DoD (fiscal, manpower, operational, etc.); Impact on weapon design… The recommendations to be developed should be approved and implemented by September 1981”.


Intrinsic Radiation Intercomparison Workshop – DOE Acknowledged Decades of Radiation Measurement Data Problems, 1981 Workshop Practical Test Failures

On January 25, 1983, DOE published a report documenting an Intrinsic Radiation (INRAD) Intercomparison Workshop hosted by the Los Alamos National Laboratory (LANL) on March 24-26, 1981. Thirty-three attendees included representatives from DOE, LANL, Sandia NL, Lawrence Livermore NL, Air Force Weapons Lab, Air Force Occupational Environmental Health Laboratory, Naval Surface Weapons Center, Chief of Naval Operations, Army Nuclear and Chemical Agency, Army DARCOM, HQ USMC, and FCDNA. A stated goal was “…compiling the available INRAD data on stockpiled weapons”.

The group reported problems with previous data and—working in a carefully controlled laboratory environment—had difficulty consistently and reliably measuring one radiation source at a time. Measurements were taken one meter from the source.8 Problems included:

  • A review of over 20 years of data showed that, in general, measurements made at different times on any particular weapon type could differ significantly. [emphasis added] This workshop was seen as a first step in quantifying the measurement variability, identifying its probable causes where possible, and, where not, outlining the future work needed to clarify these causes of variability.”

  • As this report shows, all the causes underlying the measurement diversity are not yet clearly understood, [emphasis added]and this provides a basis for future necessary action by the participating agencies.”

  • A general comment applies to all of the gamma series: an unknown portion of the measurement-range variability results in the various ways in which source energies and intensities are translated into dose rates. [emphasis added] …Identifying the conversions used may explain some of this wide variability and reduce it significantly.

  • In regard to Neutron Sources – “ It is difficult to judge instrument quality because the same type of instrument in the hands of different participants performed differently. Without resolving the questions raised above, it is impossible to decide whether better or poorer performance is due to the instrument or to the procedures and calibration techniques used. [emphasis added]It is clear, however, that high-quality standardized calibration techniques will be needed to get close interagency agreement.”

  • The range of results was excessive for warhead measurements.” [emphasis added]

Several agencies that participated in the workshop subsequently provided data, conclusions, and advice to VA for decisions on claims regarding cancers, other diseases, and death from ionizing radiation exposure to nuclear weapons. Ostensibly, they were also the ones expected to visit field units worldwide to determine INRAD levels or teach others how to do so.

The problems described in the workshop report beg questions about dose reconstruction for VA claims, and subsequent decisions on radiation exposures to Nuclear Weapons Technicians over a period of 46 years. The 2-year study was apparently used as a false premise to justify denial of veterans’ claims. One example is listed later under “VA Claim and Appeal Denials”.

Due to Nuclear Weapons Technicians’ routine and prolonged close physical proximity and direct contact with various series and numbers of live nuclear warheads, most of which no longer exist, it is not possible to reconstruct nor otherwise determine our actual individual radiation exposure doses with sufficiently reliable accuracy. The reasonable and moral assumption regarding exposure dose is that: “It is at least as likely as not, that each Nuclear Weapons Technician exceeded maximum monthly, annual and/or lifetime ionizing radiation doses allowed by an otherwise well-established and well-managed ionizing radiation safety program.”

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Footnotes:

[1] DOE-DTRA TP 4-1, Army TM 39-4-1, Navy SWOP 4-1, Air Force T.O. 11N-4-1 IC1 30 July 2016, Glossary of Nuclear Weapons Material and Related Terms. Nuclear weapons emit intrinsic radiation (INRAD): “Ionizing radiation emitted through the weapon surface or directly from exposed weapon components.”
[2] AEC-DNA TP/Army TM-39/Navy SWOP/AF T.O. 11N-35-51, section 3-4.8, 26 Nov 1962, Change 6, 7 Jun 1972
[3] Ibid., DOE-DTRA TP 4-1. Spalling. “A process of flaking in which pieces of uranium oxide spontaneously separate themselves (pop off) from the surface of the oxidized nuclear material.”
[4] Interaction of Fissionable Units, H.K. Clark, Savannah River Laboratory, Aiken, South Carolina, 9 September 1962. https://ncsp.llnl.gov/sites/ncsp/files/2021-11/ref_121.pdf. Reviewed 7-16-23.
[5] A scientific procedure undertaken to make a discovery, test a hypothesis, or demonstrate a known fact.
[6] National Personnel Records Center Fire: https://www.archives.gov/personnel-records-center/fire-1973
[7] Defense Nuclear Agency, Carter-Reagan Transition Briefing Book, December 1980, https://www.esd.whs.mil/Portals/54/Documents/FOID/Reading%20Room/Other/Carter_Reagan_Transition-6.pdf
[8] Summary Report by the Weapon and Environment Sub-Group of the Intrinsic Radiation Working Group, January 25, 1983, Lawrence Livermore National Laboratory, University of California, Livermore, CA.