Puget Sound Naval Shipyard Bremerton, Washington 13ND PSNS 5600/3A (6-78)i I t * 4 ASSESSMENT OF ENVIRONMENTAL RADIOACTIVITY AND POPULATION EXPOSURE RESULTING FROM OPERATIONS ASSOCIATED WITH NUCLEAR PROPULSION PLANT WORK AT PUGET SOUND NAVAL SHIPYARD BREMERTON, WASHINGTON December 1974 PREPARED BY THE RADIATION HEALTH DIVISION fD. A. COREY 0 Director, Radiation Health APPROVED BY: CONCURRED BY: Director, Radiological Control F. F. MANG/i Shipyard Co toTABLE OF CONTENTS PAGE CHAPTER 1 - INTRODUCTION —----------------------------------' 1 e CHAPTER 2 - AREA DESCRIPTION ———---------------------------- 3 CHAPTER 3 - PRINCIPLE RADIONUCLIDES ASSOCIATED WITH REACTOR PLANT WORK------—----------------------- 6 CHAPTER 4 - DIRECT RADIATION LEVELS------------------------- 9 CHAPTER 5 ~ ATMOSPHERIC RADIOACTIVITY ---------------------- 16 CHAPTER 6 - MARINE RADIOACTIVITY------------------'---------22 CHAPTER 7 - ESTIMATES OF RADIATION DOSE TO MAN FROM RADIOACTIVE EFFLUENTS---------------------------30 CHAPTER 8 - SUMMARY AND CONCLUSIONS-------------------------36 REFERENCES —---------------;----—---------------------------37 FIGURE- 1 - AREA SURROUNDING PUGET SOUND NAVAL SHIPYARD. FIGURE 2 - PUGET SOUND REGION FIGURE 3 - SURFACE WIND ROSES FOR WASHINGTON STATIONS FIGURE 4 - ENVIRONMENTAL MONITORING LOCATIONS FIGURE 5 - PATHWAYS FOR EXTERNAL AND INTERNAL EXPOSURE OF MAN FROM ATMOSPHERIC AND AQUATIC RELEASES OF ■ RADIOACTIVE EFFLUENTS FIGURE 6 - SHIPYARD PERIMETER AND HARBOR SURVEY RESULTS iABSTRACT Environmental radiation monitoring data of the Puget Sound Naval Shipyard through June 1974 has been evaluated to determine the levels of radioactivity in the environment and to estimate the exposure to the general public resulting from Shipyard operations associated with Naval nuclear propulsion plant work. This assessment confirms that the Shipyard has kept radioactivity in effluents to unrestricted areas and radiation exposure to the general public below detectable levels and not distinguishable from natural background.V f t CHAPTER 1 INTRODUCTION 1.1 Puget Sound Naval Shipyard Environmental Radioactivity Monitaring Program. Radiological environmental monitoring has been routinely conducted at Puget Sound Naval Shipyard since February 1963, two years before the Shipyard began working on Naval nuclear-powered ships. This environmental monitoring program has included periodic harbor bottom sampling, harbor water sampling, shoreline surveys, sampling of air discharged from radiological repair facilities, and . integrated measurements of exposure levels near the Shipyard perimeter. Results of this monitoring program have provided continuing assurance that work on nuclear-powered ships has not measurably increased the concentrations of radionuclides in the environment or measurably increased above background, the radiation exposure to the general public outside the Shipyard. 1.2 Purpose. The purpose of this assessment is to evaluate environmental monitoring data of Puget Sound Naval Shipyard to determine the levels of radioactivity in the environment and to estimate the exposure to the general public resulting from Shipyard operations. This assessment has also been performed to determine the adequacy of Shipyard controls for keeping radioactivity in effluents and exposure to the general public ’as low as practicable. 1.3 Discussion. Since beginning work on Naval nuclear-powered ships, the Shipyard in keeping with Navy policy has minimized as much as possible the amount of radioactivity released to the environment and the exposure to the general public. As indicated in Chapter 6, for example, improvements in radiological controls during this period,have resulted in a continuing decrease of radioactivity released to the harbor in spite of significant increases in workload. The Atomic Energy Commission has proposed changes to the Code of Federal Regulations (10 CFR 50)for keeping radioactivity in effluents from light water cooled reactors as low as practicable. Although these proposed regulations do not apply to operations at Puget Sound Naval Shipyard, they have been used to compare the effectiveness of Shipyard procedures. The term Has low as practicable” as used in 10 CFR 50 means as low as is practically achievable, taking info account the state of technology and the economics of improvements in relation to the utilization of atomic energy in the public interest. The proposed regulations would limit the radioactivity in effluents to provide reasonable assurance that annual exposures to individuals living near the boundary of a site where one or more light water cooled nuclear •power reactors are located will generally be less than about 5% of the average exposures from natural background radiation. The proposed regulations would also provide reasonable assurance that annual exposure to sizeable population groups will generally be less than about 1% of the exposure from natural background radiation. (Average exposures due to natural background radiation in the United States are in the range of 100-125 mRem per year). 1I This assessment first describes the area surrounding the Shipyard in terms of environmental factors which could affect the distribution of radionuclides introduced into the Shipyard environs. This is followed by a description of the radioactivity associated with Shipyard operations and an analysis of the impact of these operations on the environment and exposure to the general public. 2f CHAPTER 2 AREA DESCRIPTION 2.1 General. Located on Kitsap Peninsulaf Puget Sound Naval Shipyard lies in the central Puget Sound area approximately 15 miles west of Seattle, Washington. As shown on Figure 1, the Shipyard is bordered on three sides by the city of Bremerton, and on the fourth side by Sinclair Inlet. The city of Bremerton itself is divided in two sections by the Port Washington Narrows. The only other community of significant size near the Shipyard is Port Orchard, which is located to the south across Sinclair Inlet. The Shipyard industrial area is located on 190 acres of land with two miles of waterfront which was purchased by the U.S. Government in 1891 and designated as a Naval Shipyard in 1902. The last major waterfront construction was the building of Dry Dock 6, one of the world’s largest, which was completed in 19622. In 1961, the Shipyard was approved to-repair and overhaul Naval nuclear-powered ships. Following extensive preparation and personnel training, the Shipyard began working on nuclear-powered ships in 1965. Kitsap Peninsula, on which the Shipyard is located is shown on Figure 2 and comprises the largest land mass of the central Puget Sound region. The peninsula is located between the heavily populated and industrialized Seattle-Tacoma area to the east, and the largely unsettled and undeveloped Olympic Peninsula to the west. The shores of Kitsap Peninsula are predominantly.utilized for residential and recreational purposes. The primary economic base of this otherwise sparsely industrialized area is employment at military installations located at Bremerton, Keyport, -Bangor, and Manchester; Puget Sound Naval Shipyard at Bremerton, with approximately 10,000 employees, is the largest industry in the area. Other significant economic activities include wholesale and retail trade, construction, services, and lumber related industry. Residential development.is the fastest growing use of land in the Bremerton area while farming and forest related activities dominate the rural areas^. 2.2 Topography and Geology*1» Kitsap Peninsula is characterized by low hills, valleys, protected bays, and many small lakes. The Bremerton area, like the rest of Kitsap Peninsula, lies on a partially submerged Pleistocene glacial plain. Glacial deposits range from formations of clay and silt to layers of stratified sands and masses of small to medium gravel. The most recent deposits consist of glacial outwash, a largely unconsolidated aggregation of send, silt, gravel, and glacial till. These glacial deposits overlay the folded Tertiary rocks of the Puget Trough, a structural basin between two regions of uplift and metamorphism, the Olympic and Cascade mountain ranges. 3. * 2.3 ClimatologyH. The climate of Puget Sound region is a reflection of the moderating influences of the Sound itself, being characterized by mild temperatures, muted extremes, and narrow diurnal fluctuations. Winters are usually mild and wet with prolonged periods of cloudiness; summers are usually relatively short, cool, and dry. Much of the area’s precipitation and weather conditions are cyclonic in nature, generated by low pressure areas that travel shoreward from the Pacific Ocean along the prevailing westerlies. The Olympic Mountains, however, serve as a partial barrier to this cool, moist marine air, and as a result, the northern portion of Kitsap Peninsula lies within a rain shadow. Consequently, Bremerton weather conditions are regulated by both the cyclonic and orographic factors causing prevailing winds from the ocean to travel in the Bremerton area from the south-south-west. Surface wind data for,western Washington stations is shown in Figure 3. Data for Tacoma, Washington, is considered the most typical for the Bremerton area. The average velocity of these winds is about ten knots with southerly winds up to 80 MPH having been recorded during storms. Precipitation falls mostly in the form of rain. The annual mean precipitation for Bremerton, based on a recent 20-year average, is 52 inches, 75% of which falls between October and March. Snow on the lowlands is rare, and the frost-free season is long. Daytime high temperatures measured at Bremerton are representative of those found in Kitsap Peninsula in general, and range from averages of 45° F. for January to 7,6° F. for July. On the whole, temperatures are mild with extremes of 0° F. and 100° F. occurring only rarely. 2.4 Sinclair Inlet. Sinclair Inlet is -a relatively wide, shallow enclosed embayment approximately 5 miles long and 1 mile wide. It is connected to the rest of Puget Sound by Port Orchard Bay and Rich Passage. Inlet water depths at mean low tide vary from about 20 feet at the west end to over 60 feet at the east end. The Shipyard harbor has sufficient depth that dredging has not been required. The bottom of Sinclair Inlet is covered with an accumulation of mud composed mostly of fine sand, clay, and sediment. As expected, by its size and shape, there is a lack of well-defined tidal currents in the Inlet. The tides are of mixed type with two high and two low tides each day. The mean high and low tides are 11.7 feet and 0.0 feet respectively with diurnal inequalities. The predicted annual maximum high and low tides are 15.4 feet and minus 4.5 feet respectively$. There are significant periods when there is little or no movement of water, especially along the shoreline and at the head of the Inlet, so tidal mixing is consistent throughout the year and less than that of most other Puget Sound areas. Although prevailing southwesterly winds may aid surface mixing and flushing, exchange of water in Sinclair Inlet is slow, requiring 6 to 12 months^. A creek which flows into the Inlet at Gorst is of insufficient volume to affect flushing, tidal mixing, or tidal levels. Sinclair Inlet provides suitable habitat for a variety of fish and shellfish. Cutthroat trout are caught along the south shore, smelt Aand herring spawn in the Inlet, and salmon are commercially hatched and reared in Gorst Creek near the head of Sinclair Inlet. Some of the salmon are released to the Inlet each year from where they migrate to the Pacific Ocean. Some sport fishing for mature salmon occurs in the Inlet when these salmon return to spawn in the creekr. Recreational clam digging occurs along the north and south shorelines of the Inlet3. • £ Sinclair Inlet is heavily used by migratory waterfowl during the winter months. Typical winter visitors are black brant, grebes, scoters, mergansers, scaup, golden-eye, redhead, widgeon, and pintail. A variety,of shore birds also utilize the mud flats near the head of the bay3. 2.5 Demography7. Nearly all of Kitsap County with its population of 103,000 lies within a 15-mile radius of Puget Sound Naval Shipyard. Approximately half of this population resides within 5 miles of the Shipyard and includes Bremerton (population 36,000), Port Orchard (population 4000), and adjoining communities. The only other incorporated areas are Winslow, about 8 miles to the northeast (population 1750) and Poulsbo, about 13 miles to the north (population 2000). The remainder of the county is principally rural with scattered communities and has a population density averaging approximately 150 per square mile. Between 1960 and 1970, a trend toward an increasing population in rural areas occurred, but more recently (1970 to 1973) no significant change in population distribution has been noted. Most of the population is directly or indirectly dependent on employment provided by the area’s Naval installations. Approximately 1.8 million persons (half the population of the State) reside within 50 miles of the Shipyard. These are. principally located in a metropolitan strip on the eastern shores of Puget Sound. Major cities in this region include Olympia, the State Capitol about 40 miles to the south; Tacoma, about 25 miles to the southeast; Seattle, about 15 miles to the east; and Everett, about 35 miles northeast. The Olympic Peninsula to the west of Kitsap Peninsula is largely undeveloped and sparsely populated. Other communities in this area within 50 miles of the Shipyard include Shelton (population 6900), 35 miles southwest, and Port Townsend • (population 5200), 40 miles to .the north. A map of the Puget Sound region (Figure 2) shows the locations of the principle population centers within 50 miles of Puget Sound Naval Shipyard. 5CHAPTER 3 PRINCIPLE RADIONUCLIDES ASSOCIATED WITH REACTOR PLANT WORK 3.1 Introduction. In the shipboard reactors, pressurized water circulating through the reactor core picks up the heat of nuclear reaction. Reactor cooling water circulates through a closed piping system to heat exchangers which transfer the heat to a secondary steam system which is isolated from the primary cooling water. The steam is then used as a source of power for the propulsion plant as well as for auxiliary machinery. During reactor operation, the neutron flux in the reactor core produces a large number of radionuclides in the reactor coolant, most of which have relatively short half-lives. The principle radionuclides of importance to Naval nuclear propulsion plants are listed in Table I. Except for limited testing at the end of the overhaul or repair period, reactor plants are shut down during Shipyard overhaul or repair periods. Therefore, the short-lived radionuclides are of little consequence to Shipyard operations or in the concentration of radioactivity in the environment and exposure to the general public. 3.2 Corrosion Products. The longer-lived radionuclides usually encountered during Shipyard operations are produced when trace amounts of corrosion and wear products from reactor plant metal surfaces are activated in the reactor. Radionuclides in these corrosion and wear products with half-lives greater than one day include tungsten-187, cHromium-51, hafnium-181, iron-59, zirconium-95, tantalum-182, man-.. ganese-54, cobalt-58, and cobalt-60. Of the radionuclides normally encountered during reactor plant work, cobalt-60 is the most pre- . .' dominant and longest lived, with a half-life of 5.3 years. Since cobalt-60 also has the most restrictive concentration limit in air and water listed by organizations which set radiological control standards8'9'10 for these corrosion and wear products, Shipyard radiological control programs and waste processing procedures are conservatively controlled by assuming that all long-lived radioactivity is cobalt-60. Because cobalt-60 is also readily distinguishable from natural radioactivity present in the environment, the environmental monitoring procedures conducted by Puget Sound Naval Shipyard also emphasize the detection of cobalt-60 even though traces of cobalt-60 from weapons testing may be present. 3*3 Tritium. Small amounts of tritium are formed in the reactor coolant system as a result of neutron interaction with approximately 0.015% of naturally occurring deuterium present in water as well as other nuclear reactions, Although tritium has a 12-year half-life, the radiation produced is of such low energy that the radioactivity concentration guide issued by the International Commission on Radiation Protection, the U.S. Atomic Energy Commission, and other standardsetting organizations is 100 times higher for tritium than for cobalt-60. Tritium produced in Naval reactor plants is in the oxide form and is chemically indistinguishable from water; therefore, it does not concentrate significantly in marine life or collect on sediment as do other radionuclides. 6During Shipyard repair and overhaul periods, reactor water is collected in tanks and processed to remove the corrosion products discussed above. Since tritium remains in the water, the processed water is controlled and saved for reuse in reactor plant systems. However, since some tritium may be released to the environment, tritium is included in the estimate of exposure in Chapter 7. Tritium also occurs naturally in the environment because it is generated by* cosmic radiation in the upper atmosphere. 3.4 Short-hi v ed Rad i onuclides. The highest concentrations of shortlived radionuclides in the reactor coolant are from nitrogen-16, nitrogen-13, fluorine-18, argon-41, and manganese-56. Because of the rapid decay and limited reactor operations in the Shipyard, shortlived radionuclides are not a significant factor during Shipyard reactor plant overhaul and repairs. However, an estimate of exposure from gaseous activity released to the atmosphere is included in Chapter 7. 3.5 Fission Product Radionuclides. Fission products produced in the reactor fuel are retained within the fuel elements. The fission gases krypton and xenon are also retained within the fuel elements. Traces of naturally occurring uranium impurities in reactor structural materials release very small amounts of fission products to reactor coolant. The concentration of fission products in the reactor coolant is low compared with the higher concentrations of corrosion and activation products. However, since some krypton and xenon may be released to the atmosphere, these radionuclides are included in Chapter 7 in the estimate of exposure from airborne effluents. 7TABLE I IMPORTANT RADIONUCLIDES IN SHIPBOARD Radionuclide REACTOR PLANTS r Maximum Permissible Concentration (pCi/ml)* SZES. Half-Life Water Air Corrosion Products Tungsten-187 Insoluble 24 hours 6 x io"5 1 X 10"8 Chromium-51 Insoluble 27 days 2 x 10“3 8 X 10" 8 Hafnium-181 Insoluble 46 days 7 x 10"5 3 X 10"9 Iron-59 Insoluble 45 days 5 x 10"5 2 X 10"9 Iron-55 Insoluble 2.9 years 2 x 10"3 3 X 10~8 Zirconium-95 Insoluble 65 days 6 x 10"5 1 X 10" 9 Tantalum-182 Insoluble 112 days 4 x 10"5 7 X 10"10 Manganese-54 Insoluble 300 days 1 x 10"4 1 X 10"9 Cobalt-58 Insoluble 71 days 9 x 10"5 2 X 10"9 Cobalt-60 Insoluble 5.2 years 3 x 10"5 3 X IO"10 Fission Products I ' Iodine-131 Soluble 8.05 days 3 x 10"7 1 X io-io Strontium-90 Soluble 28 years 3 x 10"7 3 X 10"11 Cerium-144 • Soluble 285 days 1 x 10"5 3 X 10"1 0 Cesium-137 Soluble 30 years 2 x 10"5 2 X 10" 9 Krypton-83m Gas 1.9 hour s - Krypton-85 Gas 10.8 years - 3 X 10"7 Krypton-85m Gas 4.4 hours - 1 X 10"7 Krypton-87 Gas 1.3 hours - 2 X 10"8 Krypton-88 Gas 2.8 hours - 2 X 10"8 Xenon-131m Gas 11.8 days - 4 X 10" 7 Xenon-133 Gas 5.3 days - 3 X 10"7 Xenon-133m Gas 2.3 days - 3 X 10"7 Xenon-135 Gas 9.1 hours - 1 X 10" 7 * Other • Nitrogen-16 Soluble 7 seconds - - Nitrogen-13 Soluble 10 minutes - - Fluorine-18 Soluble 1.8 hours 8 x 10"4 2 X 10*7 Argon-41 Gas 1.8 hours - 4 X 10"8 Manganese-56 Insoluble 2.6 hours 1 x 10"4 2 X 10~8 Tritium Soluble 12 years 3 x 10"3 2 X IO"7 *Values obtained from reference 8, Appendix B , Table II. These values maximum permissible concentrations permitted in unrestricted areas. 8CHAPTER 4 DIRECT RADIATION LEVELS 4.1 Introduction. A major Shipyard goal is to insure that radiological operations within ‘the Shipyard do not result in significant exposure to the general public outside the Shipyard. As stated in the proposed change to 10 CFR 50t exposure to the general public should be less than 5 mRern per yeai' for individuals living near the site boundary. Although these proposed regulations would apply primarily to radioactivity in effluents, it is considered adviseable to apply this principle to exposure from direct radiation. This chapter describes the sources of direct radiation exposure, controls used to minimize direct radiation exposure from the Shipyard, and measurements of exposure levels at the Shipyard industrial perimeter. 4.2 Direct Radiation Exposure.' . ’ . 4.2.1 Exposure ~ From Natural•Sources. The sources of exposure'from external natural radiation are cosmic radiation and radioactive elements in the earth’s crust. The naturally occurring radionuclides of importance are potassium-40 and the radionuclides in the decay1 chains of uranium-238 and thorium-232. Radioisotopes commonly recognised in these chains are radium-226 with its noble gaseous.. daughter radon-222 (radon), and radon-220 (thoron), a noble gas in •the thorium chain. Natural radiation levels vary with geographical location, season, and climatic conditions. For examplef cosmic radiation generally increases with altitude, latitude, and solar flare activity, and has additional cyclic variations of about 10%. Terrestrial exposure, which includes exposure from radon decay products in the atmosphere, varies with the geology of the earth’s crust and ranges from low values for sand to high values for granite and shale. In the United States, these factors result in a variation in natural radiation levels from about 53 mRem/year to about 175 mRem/year with a mean value of 61 ± 23 mRem/year*1. Climatic conditions result in seasonal and short-term terrestrial variations primarily by affecting the ■ release of the noble gases radon-222 and radon-220 (thoron) from the earth’s crust and the dispersion of decay products in the atmosphere. For example, temperature inversion, low barometric pressure, low surface moisture, or stable air conditions may result in an increase in the exposure from radon and decay daughters. Local variations in natural radiation levels are commonly encountered which arise from rock outcropping, fill material, and concrete or brick structures, all of which increase the natural radiation level, while sand, which has a low natural radionuclide content, and water, which shields terrestrial radiation, result in lower radiation levels. Shipyard measurements with thermoluminescent dosimeters (TLD) and sensitive gamma scintillation survey meters indicate-that background radiation levels differ by as much as a factor of two in various Kitsap County Q( locations. Analysis of monitoring results can be misleading if these variations are not properly considered. Natural radiation exposure levels were estimated in 1972 by the U.S. Environmental Protection Agency as part of a study of radiation exposure to the population of the United States. The estimated external whole body exposure (excluding neutron) based on elevation, latitude, and geology for the Seattle-Tacoma area is about 81 mRem/year with approximately 35.5 mRem from cosmic radiation and 45.5 mRem from terrestrial sources12. Background measurements performed by the Shipyard during the past four calendar quarters at locations shown in Figure 1 indicate an average background of 64.4 mRem per year in Kitsap County. 4*2.2 Exposure From Fallout12. Fallout from nuclear weapons testing also causes direct radiation exposure. Without spectrometric measurements, the contribution from fallout cannot be accurately distinguished from natural sources. However, it is known that exposure from fallout has been decreasing since about 1962 and was estimated in 1972 to be less than 0.6 pRem per hour (about 5.3 mRem per year). The more recent Chinese tests have had negligible effect on direct exposure from fallout. " ' 4.2.3 Exposure From Shipyard Operations. The presence of nuclear-powered ships and associated radioactive material in the Shipyard is a potential source of external radiation exposure to the public living near the Shipyard. Shipyard radiological controls are designed to minimize the amount of direct radiation exposure to the general public to as low as practicable by utilizing radiation shields (permanent, temporary, and natural), minimizing the amount of radioactive waste generated, and performing radiological operations only within the Shipyard and away from areas occupied by the general public. 4.3 Environmental Surveillance Program. 4*3.1 Thermoluminescent Dosimeter Measurements. To provide assurance that radiological operations within the Shipyard do not cause significant exposure to the general population outside the boundary of the Shipyard, thermoluminescent dosimeters (TLDs) are‘posted-for quarterly monitoring periods at locations shown on Figure 4 between Shipyard radiologically controlled areas and the general public. (Prior to July 1973, film badges were used for this purpose). Readings from these TLDs are compared with results from control TLDs posted during the same period at several locations 5 to 10 miles away from the Shipyard as shown on Figure 1. TLDs used in this surveillance program contain two CaF2*.Mn chips secured to a heater strip encapsulated in a sealed glass bulb. The glass bulb is contained inside a plastic case with an energy compensating shield*which provides linear response to photons above 80 KeV. Prior to use, each TLD is individually calibrated and tested with a cesium-137 source (National Bureau of Standards calibrated). The standard deviation of each TLD selected 10for environmental monitoring must be less than 0.5 mRem at 15 mRem. Analysis of monitoring results verifies that quarterly exposure levels can be determined with a precision of 1 mRem at the 95% confidence levelf and annual exposure levels can be determined with a precision of 2 mRem at the 95% confidence level. Perimeter TLD results, control TLD results, and the amount by which perimeter results exceed control results for each perimeter TLD location during the past four quarters are shown in Table II. All results have been corrected for 6.1% fading based on data supplied by the manufacturer. All perimeter TLD results were significantly less than the 5 mRem per year criterion except for two locations which showed net differences of 4.6 mRem and 5.8 mRem. TLDs for the location having a net reading of 4.6 mRem were posted near a large concrete retaining wall; TLDs for the other location were posted about 100 feet inside the Shipyard perimeter in a narrow area between two paved concrete roadways with a nearby concrete retaining wall. Radiation surveys around these two locations have shown these differences in TLD results are caused by local background variations due to natural radioactivity in nearby concrete structures. Results from TLDs posted over or near the harbor are listed separately because the harbor water shields some of the terrestrial radiation. These measurements are consistent with measurements obtained in similar areas away from the Shipyard.TABLE II THERMOLUMINESCENT DOSIMETER RESULTS JULY 1973 THROUGH JUNE 1974 Perimeter TLD Total Control TLD (mRem) (mRem) TLDs located on land 66.3 64.4 49.2 (3 quarters) 48.4 64.7 - 64.4 67.0 64.4 69.0 64.4 70.2 64.4 64.9 64.4 66.4 64.4 47.0 (3 quarters) 48.4 63.4 64.4 74.8** 81.8 76.4** 81.8 67.3 64.4 64.4 64.4 66.4 64.4 61.7 64.4 65.7 64.4 67.2 64.4 62.5 64.4 66.1 64.4 61.3 64.4 TLDs located over or near harbor 53.1 64.4 56.0 64.4 55.4 64.4 26.1 (2 quarters) 32.7 52.5 64.4 56.8 64.4 Amount By Which Total Perimeter TLD Exceeds Control TLD (mRem) 1.9 0.8 0.3 2.6 4.6* 5.8* 0.5 2.0 0 0 0 0. 2.9 0 2.0 0 1.3 2.8 0 1.7 0 0 0 0 0 0 0 * These readings attributed to variation in natural radioactivity in nearby concrete structures. ** These TLDs were surrounded by thick concrete walls. Special control TLDs posted near similar structures away from any influence by Shipyard operations were used to determine appropriate background radiation levels. : 124.3.2 Sped a 1 Me a s nr erne n t s . During July 1974, a special survey was performed to check radiation levels along the entire Shipyard property line. For this survey, a gamma scintillation (Nal(Tl) crystal) survey meter, calibrated to detect gamma energies above 0.1 MeV was used. Measurements obtained during this survey are shown on Figure 6. Measurements made along,the land property line ranged from 1750 CPM to 6500 CPM with an average of 3700 CPM. Readings significantly above the average were obtained near large concrete and brick structures (none of which are used for radiological operations), near paved concrete roadways, and near a land fill area containing some excess materials, such as sandblasting sand and fire brick which contain, above average concentrations of natural, radionuclides (e.g., radium-226 and daughters). Harbor property line measurements significantly above the average harbor background level of 650 CPM were obtained near a radiological repair facility located on the end of a pier. (Above-background levels were also noted at the harbor property line during the exposure of a cesium-137 source used to calibrate radiation survey instruments. This source is located in a building near the waterfront. It is "exposed” only intermittently, less than 5% of the total time and accumulated exposure at the Shipyard boundary is insignificant.) None of the Shipyard harbor property line survey results exceeded natural background levels measured on land. Measurements at 12 residential locations away from the Shipyard ranged from 2500 CPM to 6500 CPM. The response of the Nal(Tl) detector and survey instrument used for these measurements is very dependent on gamma ray energy so results cannot accurately be converted to dose rates without special calibrations. Therefore, an 8-liter pressurized ion chamber having linear gamma ray response was used to determine the significance of the highest perimeter survey readings. Results of these readings converted to ion chamber response are listed in Table III. ■ 13TABLE III GAMMA SCINTILLATION SURVEY METER READINGS CONVERTED TO ION CHAMBER RESPONSE Location Scintillation Survey Meter Reading (CPM) Exposure Rate (mRem/hr) Estimated Annual Exposur (mRem) Harbor property line, highest reading 5000 .0050 44 Harbor background 650 .0035 31 Land property line, highest reading 6500 . 0071 62 Land property line, 3700 .0058 51 average ■ • These results show that radiation levels at the harbor property line of the Shipyard are significantly less than normal background radiation levels ashore and that the count rates recorded on Figure 6 exaggerate variations in exposure level. i a4.4 Discussion. Environmental measurements of external radiation exposure, as outlined in this chapter, verify that direct exposure to individual members of the general public from Shipyard operations during the past four quarters has been less than 5 mRem, and has been too low to distinguish from normal variations in natural background. Exposure levels at all residences adjacent to the Shipyard have been confirmed to be less than 5 mRem per year above background. Radiation levels at the Shipyard perimeter were also indistinguishable from natural background prior to July 1973 when film badges were used, thus indicating that external radiation exposure to the general public has consistently been insignificant. 15CHAPTER 5 ATMOSPHERIC RADIOACTIVITY 5.1 Introduction. An important factor of concern in the radiological control of nuclear propulsion plant work is the possible release of airborne radioactivity to the environment and its effect on individual members of the public living at the site boundary and in the adjoining communitiesAirborne radioactivity may be either gaseous or particulate. As shown in Figure 5, exposure to the population may result from inhalation of this radioactivity during the '/O.. f’respiratory process, from immersion in the dispersed radioactive *■ • • ;/:*kgakes and particulates, from exposure to the radioactivity which >has settled to produce ground contamination levels outside the nuclear r .facilities, or from consumption of food which might have picked up /.deposited radioactivity. This chapter discusses the nature of airborne radioactivity and the procedures used to minimize and measure the radioactivity which may be released to the environment from Shipyard operations. An estimation of the exposure which the general public may receive from the small amount of airborne radioactivity which may be released from the Shipyard is reported in Chapter 7. 5.2 Sources of Atmospheric Radioactivity. Natural radioactivity • found in the earth’s crust is the principle source of radioactivity in the atmosphere. The.earth’s crust contains significant amounts of natural uranium and thorium which decay through a series of daughter radionuclides. These decay radionuclides of uranium and thorium are introduced into the surface atmosphere through their noble gaseous daughters, radon (radon-222), and thoron (radon-220), which in turn decay through the uranium and thorium series respectively. The radon and thoron content of air along with their subsequent decay products depends on the amount of these noble gases that escapes from the earth. Concentration in the surface atmosphere depends primarily on prevailing atmospheric conditions such as temperature, air turbulence, precipitation, and on condition of the ground such as $oil porosity, moisture content, and snow or vegetation cover. Most of the natural radioactivity in surface air is due to radon and its daughters. Thoron’and its daughters contribute much less because of thoron’s short half-life and lower diffusion rate from the soil. The daughter products of radon and thoron are normally electrostatically charged and tend to attach themselves to the inert dust particles which are normally present in the atmosphere. Much of this radioactivity may be retained when air is filtered (or sampled) through a . high efficiency filter. The concentration of natural radioactivity in the atmosphere, principally radon-222, is 10~^ pCi/ml to 10~*0 pCi/ml, and may occasionally reach 10~g pCi/ml during periods of strong temperature inversion^. These concentrations of natural radioactivity have also been observed in air samples obtained by Puget Sound Naval Shipyard. Analysis of sample filters at least two days after sampling allows these short-lived radon and thoron daughters 16to decay permitting highly sensitive measurement for longer-lived ’’man-made" radionuclides. € Fallout/ especially following periods of atmospheric nuclear tests, c&n add to the concentration of radioactivity normally present in the atmosphere< However, because of the low levels of fallout radioactivity normally present in environmental air, the National Radiation Alert Network air sampling stations in Seattle and Spokane were placed on standby status as of January 1, 197313. 5.3 Airborne Radioactivity From Naval Reactor Plant Work. The predominant type of airborne radioactivity associated with Shipyard facilities involving overhaul and refueling of nuclear propulsion plants is insoluble radioactive material which may be suspended as small particles or attached to suspended materials in the atmosphere. Gaseous radionuclides are either retained within fuel elements or have such short.half-lives that they are not present in significant concentrations during Shipyard work to be considered. The principle radionuclides resulting from operations associated with Naval nuclear propulsion plants have been discussed in Chapter 3. The worst case estimates of quantities of radioactivity and resultant exposure are-reported using respirable particles of ‘insoluble cobalt-60 to represent all radionuclides. 5.4 Procedures for Minimizing Discharge of Airborne Radioactivity. Procedures used by the Shipyard are designed to keep levels of radioactivity in air discharged to the environment as low as practicable during repair and overhaul of nuclear-powered ships. Work areas and facilities are designed to contain radioactivity as near the source as possible by the use of special containments. In addition, each facility where radiological work is performed which could release airborne radioactivity is provided with a special ventilation system. The ventilation systems are provided with high efficiency particulate air (HEPA) filters designed to remove radioactive particulates from the air prior to discharge. Each ventilation system is tested with standard test methods developed in the nuclear industry to verify proper operation when HEPA filters are. installed and at periodic intervals. Shipyard procedures require that the ventilation system be at least 99.95% efficient for removing 0.3 micron particles. . HEPA filters have been used to filter particulate airborne radioactivity from exhausts since work on nuclear-powered ships began in the Shipyard in 1965. 5.5 Ehvironmental Surveillance Program. Since the'Shipyard began working on Naval nuclear-powered ships in 1965, continuous sampling of air downstream of HEPA filters has been performed. The present program utilizes fixed filter air samplers to continuously collect on high efficiency sample filters the particulate material from sampled air. Sample collection probes are designed and positioned in each exhaust duct to insure collection of representative samplesof air. i'or comparison purposes, integrated weekly samples of environmental air are obtained upwind and away from the facilities being monitored. To allow decay of radon and thoron daughters, samples are held at least two days before they are individually counted for gross beta activity with an anti-coincidence low background Geiger counting system. Minimum detectable concentrations with this equipment normally range from 0.1 to 1.0 x 10”^ pCi/ral depending on sampling time, exhaust volume, and counting time. If the gross beta count is greater than 2 x 10*“^ pCi/ml, the filter is analyzed with a multichannel gamma analyzer to determine if cobalt-60 or other radionuclides associated with reactor plant work are present. This action level is equivalent to typical long-lived gross beta activity (1 to 2 x lO*^*4 pCi/ml) in environmental air reported by the U. S. Environmental Protection Agency for Seattle, Washington, and Portland, Oregon, during 1973^. Results of routine sampling and analysis for airborne radioactivity for the past four calendar quarters (July 1973 through June 1974) are summarized in Table IV. In estimating the activity discharged from the Shipyard facilities, all activity (including natural and fallout) detected on the sample filters was assumed to be cobalt-60. If no activity was detected on a sample, the minimum detectable concentration was used for calculating the results reported. The results in Table IV show that air discharged from the Shipyard was at an average concentration of <0.9 x 10*”^ pCi/ml and would therefore contain <2.8 PCi of activity. For the same period, monitoring of the natural background upwind and away from Shipyard nuclear repair facilities detected higher concentrations of radioactivity in the unfiltered air of the environment. The long-lived radioactive particulate concentration at the control location averaged 3.7 x 10"^ pCi/ml. If the same volume of air as discharged from exhaust stacks of the Shipyard repair facilities were from the environment, it would have contained approximately 12 yCi of long-lived radionuclides. Thus, the concentration of radioactivity in air released from Shipyard facilities was significantly less than the concentration normally present in the environment. 18TABLE IV SAMPLING RESULTS JULY 1973 ~ JUNE 1974 * Facilities Total Air Discharged (m3) Total Activity Discharged (vCi) Average Concentration (pCi/ml) Repair 16.5 x 107 <0.46 0.3 x 10“lu Building Dry Dock 5.4 x 107 <1.4 2.6 x IO-14 Dry Dock 1.2 x 107 <0.04 0.4 x 10"lt+ Dry Dock 2.6 x 107 <0.15 0.6 x IO"1** Dry Dock 5.6 x 107 <0.76 1.4 x IO-14 Chemistry 0.5 x 107 <0.01 0.2 x IO"14 Labs 12-Month 3.2 x 108 <2.8 0.9 x IO"14 Summary Background *11.8 3.7 x 10“lk * 3.2 x IO8 of environmental air would have contained 11.8 pCi 195.6 Special Air Samples From Radiological Storage Facilities, Continuous monitoring of air from radioactive material storage areas is not done because radiological work is not performed there, and all radioactively contaminated material is packaged to contain the radioactivity. To check whether significant radioactivity may be present, special samples v/ere taken during July 1974 from the two principle facilities used for temporary storage of radioactive material. Control samples were taken upwind and away from the Shipyard radiological work and storage areas; one location was near the Shipyard perimeter, and the other about 5 miles southwest of the Shipyard. Samples were analyzed for gross beta activity in a low background counter and for isotopic content with a multichannel analyzer. Air sample data and analyses are reported in Table V. Ko cobalt-60 was detected in' any sample, and no significant difference could be distinguished between the storage area sample results and the control results, confirming that continuous air sampling of storage facilities is not required. 20TABLE IV STORAGE FACILITY AIR PARTICLE SAMPLES Sample Location Sampling Period (Date/Time) Sample Volume Analysis Date/Time Result (yCi/ml) Waste Storage 7/15/74, 11.45 m3 7/16/74, 1245 4.2 x 10“13 Facility 1457 to 1551 7/18/74, 1645 1.4 x 10~13 Sample #1 Waste Storage 7/16/74, 4.6 m3 7/16/74, 1105 7.5 x 10"12 Facility 0823 to 0844 7/19/74, 1100 0.1 MeV (ppCi/gm) Range of Gross Gamita Highest/Lowest (ppCi/gm) 1966 143 1.6 7.8/. 4 1967 140 1.3 11.0/.2 1968 140 1.2 12.7/.2* 1969 138 1.3 7.6/.2* 1970 141 0.8 5.1/.2* 1971 150 0.8 4.5/.1* 1972 156 0.8 6.3/.2* 1973 162 0.8 5.0/.2* 1974 (First 82 0.7 ■ 1.9/.3 half only) * The “lowest" value noted is the minimum detectable activity which varied with sample weight and counting parameters. As noted in Table VII, there has been a general decrease of gross gamma radioactivity since the program was initiated. This is attributed to decreasing levels of fallout from weapons tests. Of 1252 samples analyzed since 1966, no cobalt-60 has been detected above the minimum detectable activity of approximately 0.2 uyCi/gm. 25To check whether radioactivity may have accumulated below ‘the sediment surface not being sampled by the routine program, core samples were obtained from two locations during July 1974. Two-inch diameter by one-foot deep core samples were collected from two locations shown in Figure 4. One location was selected because it is under the radiological repair facility from which previous releases of processed water have been made. The other location was selected because routine samples from this area have consistently shown the highest gross gamma results with naturally occurring radium-226 and daughters identified by spectral analysis. Each core sample was divided into sectionsf placed in a standard sediment counting container, and analyzed for gamma activity and isotopic content with a multichannel analyzer. Results listed in Table VIII show that concentrations of natural radioactivity at varying depths are consistent. No cobalt-60 was detected in either sample. The Washington State Department of Social and Health Services has periodically obtained a few sediment samples at Bremerton. Results of these independent measurements have confirmed Shipyard findings and consistently reported the absence of cobalt-60 or other radionuclides which may be attributed to reactor plant operations. The State's report for July 1972 through June 1973, for example, reported that cobalt-60 was less than 0.02 ppCi/gm13. 26TABLE VIII CORE SAMPLE RESULTS i r Sample Location Sample Depth (Inches) Sample Weight (gm) c co-60 Energy Range (ypCi/gm) Gross Gamma (Co-60 Equivalent) (ppCi/qm) Previous Top of- core incl 102 0.4* 0.7 . waste liquid discharge point 0 to 1-1/2 1-1/2 to 3-1/2 156 0.2* 0.8 3-1/2 to 5-1/2 168 0.2* 1.0 5-1/2 to 7-1/2 158 0.2* 0.6 7-1/2 to 9-1/2 155 0.2* 0.7 9-1/2 to 11 211 0.3 1.1 Area of Top of core incl 325 0.2 0.8 highest liquid gross gamma 0 to 2-1/2 activity 2-1/2 to 4-1/2 223 0.2 1.1 4-1/2 to 6-1/2 " 236 0.2 0.9 6-1/2 to 12-1/2 670 0.1 0.6 NOTES: (1) Naturally occurring radium-226 and daughters and potassium-4 detected in all' samples. (2) No cobalt-60 detected in any sample. Radioactivity reported in the cobalt-60 energy range is attributed to the influence of radium-226 and daughters and potassium-40. * Recorded results are minimum detectable activities (MDA) for these analyses-at 90% confidence and 30% error. Counting results were below MDA. 276.3,3 Shoreline Surveys. Radiation surveys of shoreline areas exposed at low tides have been conducted at Puget Sound Naval Shipyard in the areas shown on Figure 4 during the second and fourth quarters of each year. A gamma survey instrument equipped with a Nal (Tl) scintillation detector calibrated to detect gamma energies above 0.1 MeV has been used to perform these surveys. Measurements were taken along the shoreline at three feet above ground level. Background measurements were taken in areas away from the shoreline. Results of these surveys show there has been no detectable increase in shoreline radiation levels. 6/3.4 Special Marine hife_ Measurements. On two occasions, marine life has been checked to determine if it may be concentrating very low nondetectable levels of radioactivity to higher, more easily detectable levels. During June 1972, twenty-four marine life samples were collected from pilings and bulkheads where wave and tide action may transport radioactivity. Direct radiation measurements of these areas were also made with a sensitive scintillation survey meter. The marine life samples and direct radiation measurements were taken at pilings, pier supports, and bulkheads adjacent to and away from nuclear ship moorage and radiological repair facilities. Measurements of direct radiation levels of pilings and walls near nuclear ship moorages and radiological repair facilities were not distinguishable from measurements made away from these locations; neither was any difference detected between relatively bare structures and the structures covered by marine life. Marine life samples consisted of several varieties which attach themselves to the pier structures. These included starfish, barnacles, mussels, sea anemones, and sea cucumbers. These samples were analyzed with a multichannel analyzer. All samples were less than the minimum detectable activity (typically 0.3 to 0.8 ppCi/gm) and no cobalt-60 or other radionuclides associated with the Naval reactor plant program were identified, ' During July 1974, several marine life samples were collected from the harbor bottom at the location shown in Figure 4. This location was chosen because water processed to remove most of the radioactivity had been previously released from this point. Samples were placed in standard one-quart counting containers and analyzed for gamma activity and isotopic content with a multichannel analyzer. Results are reported in Table IX. cobalt-60 or other radionuclides asso-. dated with the Naval reactor plant program were detected above the minimum detectable activity. 28TABLE IX MARINE LIFE SAMPLES r Gross Gamma ' (Co-60 Equivalent) (yyCi/grn) Net Weight (grams) Co-60 Energy Range (yvCi/gm) Bullhead (bottom feeding fish) 364 0.26* 0.28* Starfish 580 0.16*. 0.18* Scallops, crabs, 674 0.14* f 0.16 * Recorded results are minimum detectable activities for these analyses at 90% confidence and 30% error. Actual counting results were below minimum detectable activity. 6.4 Summary. Environmental measurements of the harbor performed to date indicate there is no significant buildup or concentration of radioactivity associated with Naval nuclear reactor plant work in harbor water, sediment, or marine life. Although too low to measure, an estimation of exposure the general public could receive from the small amounts of radioactivity which may be released to the harbor is provided in Chapter 7. . 29CHAPTER 7 ESTIMATES OF RADIATION DOSE TO MAN FROM RADIOACTIVE EFFLUENTS 7«1 Introduction. The radiation dose to an individual at the Shipyard boundary and to the general population outside the Shipyard is estimated by calculation because quantities of radioactivity in effluents are so low that such exposures to individuals are not measurable. The calculated radiation dose to a person residing at the Shipyard boundary and the total man~Rem whole body dose to the population within 50 miles of the Shipyard as a result of Shipyard operations are shown in this chapter. 7.2 Dose from Airborne Releases. Release of radioactivity to the atmosphere can result in radiation exposure to man via several pathways as shown in Figure 5. These are: (a) Inhalation of airborne radioactivity; (b) ingestion of foodstuffs contaminated as the result of deposition of airborne radioactivity; (c) direct external exposure from airborne radioactivity deposited on the ground; or (d) direct external exposure from airborne radioactivity. The doses to man via these pathways have been conservatively estimated for the particulate and gaseous radioactivities expected to be contained in the air released from Shipyard facilities. As indicated previously, cobalt-60 is the particulate activity of primary concern due to its concentration in reactor systems, half-life and decay energy. All particulate emissions are therefore considered to be insoluble cobalt-60. The radioactive noble gases released include the fission product gases xenon and krypton and the activation product, argon. In addition, small amounts of tritium in the form of tritiated water vapor may be released. To provide a conservative estimate of exposure to the population surrounding the Shipyard, 0.0001 Ci of particulate activity (cobalt-60) is assumed to be released each year (this amount is about 40 times the gross radioactivity including natural radioactivity actually measured in exhaust air for the 12-month period ending 30 June 1974 as reported in Chapter 5). Similarly, 1 curie of noble gases (xenon, krypton, and argon), and 0.001 curie of tritium are assumed to be released to the atmosphere annually. These amounts of noble gases are conservative estimates based on information provided by Naval Sea Systems Command. • The meteorology of the Puget Sound Basin has been studied and reported in Reference 4 for the proposed Trident Support Site located about 15 miles north of the Shipyard. Based on the annual "worst case" 30conditions listed in Table 6 of reference 4, a wind speed of approximately 4.5 miles per hour and a Pasquill’s Type D diffusion condition and the above assumed radioactivity releases, the annual average downwind concentrations of airborne effluents released at ground level were calculated out to 50 miles following the procedures contained in reference 17. These concentrations, adjusted for annual wind frequencies,, were used to estimate the maximum annual exposures to a person at the Shipyard boundary and are shown in Table X. TABLE X MAXIMUM ANNUAL EXPOSURES Exposure Pathway Critical Body Organ Estimated Annual Dose (mRem)* Inhalation Lung 0.003 Ingestion Whole body Lower large 0.0001 (tritium) intestine 0.001 Direct exposure from deposited activity Whole body 0.001 Direct exposure from $ Whole body 0.002 airborne activity Skin 0.003 w Millirem = 1CT3 Rem In each case, the above estimated annual exposures represent less than one ten-thousandth of the applicable AEC radiation protection standards for individual members of the public. This exposure is indistinguishable from normal background levels which are many orders of magnitude higher. Calculations indicate that the total whole body man-Rem dose to the approximately 1.8 million people living withih 50 miles of the Shipyard is less than 0.02 man-Rem per year as a result of airborne radioactivity released from the Shipyard. 7.3 Estimates of Radiation Dose From Exposure to Liquid Effluents. Shipyard operating procedures require collecting all radioactive water for processing. However, a small amount of the radioactivity may be released into the harbor. The amount of radioactivity entering Sinclair Inlet is conservatively estimated to be less than 0.001 curie per year excluding tritium. The tritium released to Sinclair Inlet is estimated to be less than 0.1 curie per year. Except for tritium, the small amount of radioactive material released to the 31r j harbor will be dispersed to some extent by tidal action arid most of it will deposit in bottom sediment. Tritium in the oxide form is indistinguishable from water and will eventually be evenly distributed in the harbor water. If the cobalt-60 radioactivity were to settle to the bottom into a one-inch deep layer of sediment, the average activity would be approxi mately 0.003 ypCi per gram in Sinclair Inlet. The release of radioactivity to the harbor can result in radiation dose to man via the following pathways, as shown in Figure 5: (a) Ingestion of marine varieties of fish, mollusks and Crustacea, including their sediments; (b) ingestion of drinking water; (c) external exposure from shoreline contamination; and (d) external exposure from swimming in Sinclair Inlet. Salt water from Sinclair Inlet is not used as a supply of drinking water. However, for this calculation, the maximum concentration in. the area drinking water is conservatively assumed to be the same as that which could exist in the harbor. Marine*organisms, including fish, Crustacea and mollusks ingested by man are assumed to reconcentrate radionuclides by the factors shown in Table XI. In using these concentration factors, it is conservatively assumed that all of these radionuclides are in the soluble form. Swimming in Sinclair Inlet is restricted because of a sewage outfall; however, external exposure from swimming and shoreline contamination is conservatively based on the radioactivity which could exist in the harbor water and bottom sediment. 32TABLE XI MEAN CONCENTRATION FACTORS18 FOR MARINE ORGANISMS (yCi/g per pCi/ml) Nuclides Mollusks Crustacea Fish Cesium 15 18 48 Strontium 2 1 0 Manganese • 22,000 2,300 360 Cobalt 170 1,700 650 Zinc 47,000 5,300 . ' 3,400 Iron 7,600 2,000 1,800 Iodine - 5,000 31 10 Cerium - 240 88 99 Potassium 8 12 • 16 Calcium 16 40 2 Rubidium 17 13 17 Ruthenium 2 38 7 Zirconium-Niobium 81 51 86 These concentration factors in salt water are generally less than concentration factors for organisms in fresh water. 33TABLE XII PARAMETERS USED FOR CALCULATION OF RADIATION DOSES FROM LIQUID EFFLUENTS Pathway Location Annual Usag Maximum Individual (Adult) Pish Within 1.5 miles from facility 18 kg Crustacea Within 1.5- -miles from facility 9 kg Mollusks Within 1.5 miles from facility 9 kg Sediment Within 1.5 miles from facility 1 kg Drinking Within 1.5 miles from facility 730 liters Swimming Within 1.5 miles from facility 100 hrs Boating Within 1.5 miles from facility 100 hrs Shoreline Site boundary 500 hrs General Population (1.8 million persons within 50 miles) Fish From general vicinity of site 2.3 kg Crustacea From general vicinity of site 0.9 kg Mollusks From general vicinity of site 0.2 kg Sediment From general vicinity of site 0.1 kg Drinking 20-mile radius 180 liters Swimming 3-5 miles from facility 1 hr Boating 3-5 miles from facility 1 hr Shoreline 3-5 miles from facility 5 hrs * Based on reference 19 ♦ 34The corresponding annual usage value shown in Table XII and the estimated releases were used to estimate the annual rate of activity intake (or exposure) for each pathway. These values were in turn compared with the AEC guidelines on annual rate of intake by "standard man" for a given annual dose to generate an estimate of the corresponding fractional dose for each pathway. .The resulting dose values are shown in Table XIII. TABLE XIII Maximum Dose to an Individual ’ Estimated Annual Dose Pathway (mRem/yr) Cobalt-60 Tritium Fish 2.48 x 10"3 0.16 X 10"6 Crustacea 3.26 x 10~3 0.08 X 10~6 Mollusks 0.33 x 10"3 0.08 X io~ e Sediment 3.12 x 10"3 0.01 X 10"6 Drinking 0.16 x 10"3 0.46 X 10"6 Swimming 0.0003 x 10"3 0.00 X 10-6 Boating 0.0001 x 10"3 0.00 X 10" s Shoreline 5.0 x 1073 0.00 X 10“6 Total 13 x 10"3 0.79 X 10-6 Maximum Dose to General Population Fish 0.032 x 10"3 0.0020 X 10“ 6 Crustacea 0.033 x 10"3 0.0008 X 10"6 Mollusks 0.006 x 10"3 0.0002 X 10-6 Sediment 0.031 x l0"3 0.0001 X 10-6 Drinking 0.0004 x 10"3 0.016 X 10“ 6 Swimming 0.0000003 x 10"3 0.000 X 10”6 Boating 0.0000001 x 10"3 0.000 X 10-6 Shoreline 0.005 x 10~3 0.000 X 10" 6 Total (each) 0.10 . x 10~3 0.019 X 10" 6 In each case, the estimated annual doses represent less than one-millionth of the applicable AEC radiation protection standards8 for individual members of the public and would be indistinguishable from normal background levels and fluctuations. Exposure from fission products and other activation products was found to be less than one percent of the total dose. , • Based on the above table, the total whole body, man-Rem dose to the approximately 1.8 million persons residing within 50 miles of Puget Sound Naval Shipyard is estimated to be less than 0.18 man-Rem per year as a result of radioactivity release in effluents to Sinclair Inlet. 35CHAPTER 8 SUMMARY AND CONCLUSIONS 8.1 Summary. An evaluation has been made of the environmental surveillance data for Puget Sound Naval Shipyard, This evaluation was performed to determine levels of radioactivity in the environment , to estimate exposure to the general public resulting from Shipyard operations, and to compare the Shipyard’s performance with the proposed standards of 10 CFR 50 for keeping radioactivity in effluents as low as practicable. Worst case estimates of exposure to the general public from radioactivity in effluents released to the environment have been reported in Chapter 7. Combining the "whole body" exposure from liquid and airborne radioactivity in these effluents, the maximum exposure an individual could receive who lives at the Shipyard perimeter is estimated to be less than 0.02 millirem per year. The same person receives approximately 100 millirem per year from natural background radiation. The total whole body man-Rem dose to the approximately 1.8 million persons residing within 50 miles of Puget Sound Naval Shipyard ‘is estimated to be less than 0.2 man-Rem per year. The total man-Rem dose from natural background radiation to the same population is approximately 200,000 man-Rem per year. Integrated measurements at the Shipyard perimeter verify that direct radiation exposure from operations .at Puget Sound Naval Shipyard to individuals living nearby is less than 5 mRem per year. It is evident from this evaluation that levels of radiation exposure in unrestricted areas from work associated with Naval nuclear propulsion plants are indistinguishable from, and less than, exposures due to normal variation in natural background radiation. 8,2 Conclusion. This assessment confirms that the Shipyard has kept radioactivity in effluents to unrestricted areas and radiation exposure to the general public as low as practicable. Although the proposed requirements of 10 CFR 50 do not apply to Shipyard operations, this assessment shows that the Shipyard procedures are effective in meeting these stringent control criteria. 36REFERENCES 1. FEDERAL REGISTER, Vol 36, No 111, pp 11113-11117 (June 9, 1971). 2. PUGET SOUND NAVAL SHIPYARD. Puget Sound Naval Shipyard, Bremerton, , Washington: The First 75 Years, Special Anniversary Publication (1966) . 3. KRAMER, CHIN, MAYO, INC. Environmental Impact Assessment, A Comprehensive Sewerage System Improvement Plan for the City of Bremerton, Washington. Seattle, Washington (1973). 4. DEPARTMENT OF THE NAVY. ■ Trident Support Site,'Bangor, Washington, Draft Environmental Impact Statement, Appendices F and G (Mar 1974). 5. Puget Sound Naval Shipyard, Bremerton, Washington, Predicted Tide Curve, 1974. 6. Oil on Puget Sound. University of Washington Press (1972). 7. Official April 1, 1973 Population of the Cities, Towns, and Counties, State of Washington. 8. U.S. ATOMIC ENERGY COMMISSION. Standards 'for Protection Against Radiation. Code of Federal Regulations, Title 10, Part 20. 9. NATIONAL COUNCIL ON RADIATION PROTECTION AND MEASUREMENTS. Maximum Permissible Body Burdens and. Maximum Permissible Concentrations of Radionuclides in Air and in Water for Occupational Exposure. Report No. 22. Published as National Bureau of Standards Handbook 69 June 1959), superseding Handbook 52. 10. INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION. Report of Committee II on Permissible Dose for Internal Radiation. Publication 2, with 1962 Supplement issued in ICRP Publication 6 (1959). Recommendations on Radiation Exposure. Publication 9 (1965). Publication 7, amplifying specific recommendations of Publication 9 concerning environmental monitoring (1965). 11. EISENBUD, Merril. Environmental Radioactivity. Academic Press (1973). 12. U.S. ENVIRONMENTAL PROTECTION AGENCY. Natural Radiation Exposure in the United States, ORP/SID 72-1 (June 1972). 13. WASHINGTON STATE DEPARTMENT OF SOCIAL AND HEALTH SERVICES. Environmental Radiation Surveillance in Washington State. 12th Annual Report (July 1972 to June 1973). 3714. U.S. ENVIRONMENTAL PROTECTION AGENCY. Radioactivity in Airborne Particulates and Precipitation ~ Results for 1973. Radiation Data and Reports, Vol 14 and 15. 15. NATIONAL ACADEMY OF SCIENCES, Radioactivity in the Marine Environment (1971). - 16. DEPARTMENT OF THE NAVY. Trident Support Site’, Bangor, Washington, Pinal Environmental Impact Statement (July 1974).. 17* SLADE, D, H, , Editor. Meteorology and Atomic Energy, 1968, TXD-2419G. National Technical Information Service, Springfield, VA (July 1968). 18. JINKS, S. M. and M. EISENBUD. Concentration Factors in the Aquatic Environment. Radiation Data and Reports (May 1972). 19. U. S. ATOMIC ENERGY COMMISSION. WASH-1258, Vol 1, Final Environmental Statement concerning Proposed Rule Making Action? Numerical Guides, and Vol 2, Analytical Models and Calculations. Directorate of Regulatory Standards (July 1973). 383 4 PUGET SOUND NAVAL SHIPYARD 0 1 2 SCALE (miles! □ £ Control TLD Location < figure: i SCALE (miles)SURFACE WIND ROSES FOR WASHINGTON STATIONS -U-Sz KM <«« FfiWf WORTH KAO ti &®e» twa®? &&vfcl'ito«fcs'L» g C-T < WOOSH ELAKDOJ WOOSH tSLAHOW tfimtss o rwfrM r »@ ejrKjs© a» rsie TIGURE 3'i } ENVIRONMENTAL MONITORING LOCATIONS PUGET SOUND NAVAL SHIPYARD BREMERTON, WASHINGTON FIGURE 4 k- G> & Industrial Security . Fence Line' 1 I o. o 7? © CORE SAMPLE OSEDIMENT SAMPLE POINT A WATER SAMPLE POINT O PERIMETER DOSIMETRY DEVICE ^SHORELINE SURVEY J ©027 O o O 2...._____opo SCALE (FEET)ATMOSPHERIC RELEASES AQUATIC RELEASES PATHWAYS FOR EXTERNAL AND INTERNAL EXPOSURE OF MAN FROM ATMOSPHERIC AND AQUATIC RELEASES OF RADIOACTIVE EFFLUENTS. FIGURE 5'4