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1Title:  Occupational radiation exposure from Naval Reactors' Department of Energy facilities Add
 Summary:  This report focuses on radiation exposure at facilities managed by the Department of Energy's Office of Naval Reactors. As noted in the report, "the policy of the Naval Reactors Program is to reduce exposure to personnel from ionizing radiation associated with Naval Reactors' Department of Energy facilities to a level as low as reasonably achievable" (5). Naval Reacors "operates two Department of Energy laboratories; one Department of Energy site with two operating and one inactive prototype naval nuclear propulsion plants; one Department of Energy site that operates the Expended Core Facility (for dispositioning of naval fuel and examination of irradiated test specimens) and has three inactive prototype nuclear propulsion plants; and nuclear component engineering and procurement organizations" (1). These facilities provide support for the United States Navy's 82 combatant vessels (submarines and aircraft carriers). For the prototype plants, the major source of radiation expoure is maintenance inside the reactor compartments during shutdown periods, specifically "cobalt-60 deposited inside the [primary] piping systems" (6). The report describes the sources of exposure at other facilities, such as the Idaho National Laboratory's Expended Core Facility. It also provides information on exposure at the Shippingport Atomic Power Station, which operated from 1957 to 1982. The use of the Light Water Breeder Reactor (LWBR) core at Shippingport (the first core that successfully bred fuel in a water-cooled reactor) led to extremely high radiation exposures as the core was fabricated; this exposure, which dramatically increased total exposure in the 1974-1976 time period, is shown in figure 1. Finally, the report includes information on dosimetry devices used in the program and the training required of civilian specialists who support prototype operations. Note that the report does not include exposure information for the moored S5W training prototype plants operated by the Navy in Charleston, South Carolina. 
 Date:   2010 
 Subject(s):  Health physics | Naval Reactors 
 Type:  Text 
 Format:  PDF 
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2Title:  Occupational radiation exposure from U.S. naval nuclear plants and their support facilities Add
 Summary:  As noted in the summary, this report describes "radiation exposures to Navy and civilian personnel monitored for radiation associated with U.S. naval nuclear propulsion plants" (1). Most of the exposure comes "from inspection, maintenance, and repair inside the reactor compartment [following reactor shutdown]. The major source of this radiation is cobalt-60 deposited inside the piping systems" (5). Additionally, "the radiation exposures in this report are almost entirely from gamma radiation," given the low level of neutron radiation following shutdown (9). The report describes the high priority placed by the Naval Reactors organization on reducing exposure, noting that "shield design criteria establishing radiation levels in various parts of each nuclear-powered ship are personally approved by the Director, Naval Nuclear Propulsion" (5). It provides an in-depth summary of personnel dosimetry used in the Naval Nuclear Propulsion Program throughout its history. The move from calcium fluoride thermoluminescent dosimeters (TLDs) to lithium fluoride TLDs began in 2006 in shipyards that perform nuclear propulsion work; the transition to lithium fluoride TLDs throughout the program, including the fleet, was completed in 2010. With lithium fluoride dosimeters, it's possible, using a methodology described in the report, to estimate background radiation sources and subtract background exposure from the "program sources of radioactivity" received by shipboard personnel (8). As a result of the move to lithium fluoride TLDs, the total fleet exposure markedly decreased in 2010 (compared with 2009), as described in the summary. Finally, the report describes the radiological controls training required for naval personnel in the nuclear propulsion program and for workers in shipyards supporting nuclear construction and maintenance work. In summary, this report provides a concise and informative study of the program's approach to radiation exposure, both in the past and current practices, including information on radiation sources, dosimetry, required physical examinations, and training. 
 Date:   2011 
 Subject(s):  Health physics | Naval Reactors 
 Type:  Text 
 Format:  PDF 
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