The US Nuclear Submariner Cohort – Robust and Healthy due to extremely low doses.

The source document used to obtain the health and radiation exposure information in this precis is: “OCCUPATIONAL RADIATION EXPOSURE FROM U.S. NAVAL NUCLEAR PLANTS AND THEIR SUPPORT FACILITIES”, REPORT NT-11-2 MAY 2011, NAVAL NUCLEAR PROPULSION PROGRAM, DEPARTMENT OF THE NAVY, WASHINGTON, D.C. 20350

The quotes taken from the above documents are limited to those sections relevant to the US Navy’s Nuclear Submariner cohort.  The characteristics of these people include annual exposure doses significantly below those experienced by the US civilian population, and substantially below those experienced by people living in defined Naturally High Background Radiation Areas of the world as explained as follows by the US Navy.  The US Nuclear Submarine Cohort experience the lowest annual exposure doses in the US Nuclear Navy.

I am using this example because I hold that : The very  low exposures experienced at great depths for long periods of time by the US Nuclear Submariners appear to confront the primary tenant of the  School of Hormesis.  That is, the concept of the “beneficial dose band”. Or “too much radiation is a problem, just as too little radiation is a problem” (see Sykes, 2011, Scott, 2004, Brucer, 1954).   Hormesis  claims  that the drive to reduce human exposure doses down to levels which are As Low As Reasonably Achievable is detrimental to human health. (Brucer ) My view is my view. Make of the whole US Navy document what you will. To me, the document tends to validate ALARA over hormesis most clearly.

The US Navy document quoted below carries no restrictions. The document is freely available from US Defense Technical Information Center and from the following link :

Nuclear Navy

Quote:

“For submarine personnel stationed outside the propulsion plant, the combination of low natural radioactivity in ship construction materials and reduced cosmic radiation under water results in less radiation exposure (from all sources including the nuclear reactor) at sea than the public receives from natural background sources ashore. Those who operate the nuclear propulsion plant receive more radiation exposure in port during maintenance and overhaul periods than they receive from operating the propulsion plant at sea.”pp 5,6.

“the annual exposures for personnel in the Naval Nuclear Propulsion Program may also be compared to natural background and medical exposures:
The maximum annual exposure for Program personnel of 2 rem is less than half the annual exposure from natural radioactivity in the soils in some places in the world, such as Tamil Nadu, India, and Meaipe, Brazil (reference 17).

“The average annual exposure of 0.042 rem since 1980 for Fleet personnel is:
less than 15 percent of the average annual exposure to a member of the population in the U.S. from natural background radiation (reference 11).
less than the difference in the annual exposure due to natural background radiation between Denver, Colorado, and Washington, D.C. (reference 22).

“Fleet personnel operating nuclear-powered submarines receive less total annual exposure than they would if they were stationed ashore performing work not involving occupational radiation exposure.

“This exposure is less because of the low natural background radiation in a steel hull submerged in the ocean compared to the natural background radiation from cosmic, terrestrial, and radon sources on shore (and the effectiveness of the shielding aboard ship).” pp 41

The average annual exposure of 0.097 rem since 1980 for shipyard personnel is:
approximately one-third the average annual exposure to a member of the population in the U.S. from natural background radiation (reference 11).
less than the exposure from common diagnostic medical procedures such as
an x ray of the back (reference 11).” pp 42

“….The preceding statements show that occupational exposures to individuals working in
the Naval Nuclear Propulsion Program are small when compared to other occupational
exposures and limits and are within the range of exposures from natural background
radiation in the U.S. and worldwide. Additionally, the total dose to all persons (collective
dose) each year is small compared to the collective doses to workers in other
occupations, and insignificant compared to the collective doses to the U.S. population
from natural background radiation, medical procedures, and tobacco smoke. In
reference 18 the National Council on Radiation Protection and Measurements reviewed
the exposures to the U.S. working population from occupational exposures. This
included a review of the occupational exposures to personnel from the Naval Nuclear
Propulsion Program. Based on this review, the National Council on Radiation Protection and Measurements concluded:
These small values [of occupational exposure] reflect the success of the Navy’s efforts to keep doses as low as reasonably achievable (ALARA). ”

“In 1987, the Yale University School of Medicine completed a study (reference 36) sponsored
by the U.S. Navy Bureau of Medicine and Surgery of the health of Navy personnel assigned to nuclear submarine duty between 1969 and 1981. The objective of the study, begun in 1979, was to determine whether the enclosed environment of submarines has had any impact on the health of these personnel. Although not strictly designed as a cancer study of a low-dose population, the study did examine cancer mortality as a function of radiation exposure. The study concluded that submarine duty has not adversely impacted the health of crew members. Furthermore, there was no correlation between cancer mortality and radiation exposure. These observations were based on comparison of death rates among the approximately 76,000 officers and enlisted submariners (all who served between 1969 and 1981) with an age-matched peer group. The results of this study were published in the Journal of Occupational Medicine (reference 37). Table 8 below summarizes the Yale study results for enlisted submariners. The officer data show similar trends. (Note the SSBN population was larger than the fast-attack submarine [SSN] population, hence the larger number of expected cancer deaths. Also, SSBN & SSN is defined as “service aboard both types of submarines.”) As seen in Table 8, cancer deaths among both SSBN and SSN Sailors are less than cancer deaths among their age-matched peers in the civilian population.

 

“In 1996, New York University (NYU) was contracted to update and expand the Yale Study, updating the vital statistics of the cohort through 1995. Updating the Yale study was appropriate because of the increased follow-up time and more statistical power provided by the aging cohort. NYU completed their study update and provided a report to the Navy in 2001. Among the 85,498 enlisted submariners in the expanded cohort -50-
3,263 deaths (3.8%) from all causes had occurred by the end of 1995, which is 30% less than would be expected when compared to age-matched peers in the civilian population. Consistent with the Yale study, the NYU study team concluded that there is no evidence of increased cancer from chronic low doses of ionizing radiation associated with this cohort. Table 9 below summarizes the NYU study results….. ” end quotes.

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