Radioactivity in the Marine Environment (1971) / Chapter Skim
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SOURCES OF RADIOACTIVITY AND THEIR CHARACTERISTICS
SOURCES OF RADIOACTIVITY AND THEIR CHARACTERISTICS
Pages 6-41
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From page 6... ...
involve the radioactivity derived from the fission or fusion processes-either fission products or activation products. The greatest future source of radioactivity will be nuclear reactors, assuming that the atmospheric nuclear testing moratorium will continue.
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From page 7... ...
Encapsulated radioisotopes Radionuclides Steam, electricity Heat, electricity, neutrons Kinetic energy Electricity Gamma and beta radiation Beta and gamma radiation Electric power-stationary or portable plants, desalination, propulsion of submarines and surface ships Spacecraft and satellite power, spacecraft propulsion, research and special materials production Military and civilian applications: large-scale earth moving, subsurface excavation, mineral extraction from underground Marine navigation aids, unmanned weather stations, spacecraft project power, artificial human organs Food preservation, polymerization, sterilization of medical supplies, thickness gauges Medical uses, tracers in scientific research, measures of manufacturing processes activity would amount to approximately 700,000 Ci (U.S. Public Health Service, 1960)
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From page 8... ...
Radioactivity in the Marine Environment TABLE 2 Concentrations of Natural Radionuclides in the Sea" In Seawater Radionuclide Half-life g/liter dpm/liter In Sediments (g/g) Terrigenous Origin Potassium-40 1.25 X 109yr 4.7 X 10-5 670 (0.8-4.5)
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From page 9... ...
The production of other fission products can be estimated similarly, using the fission yield and half-life data tabulated by Hallden et al.
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Sherer, Lawrence Radiation Laboratory, Livermore, Calif., personal communication)
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However, because of the late time of sampling, Heft's samples, similar to Nathans', contained very little of the larger end of the particle size spectrum. In any event, there appears to be a physical basis for a multimode set of particle distribution functions describing the debris as a whole.
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From page 12... ...
3. Unmelted environmental material, swept into the nuclear cloud by the afterwinds, to which fission products or small condensed radioactive agglomerates attach by surface impaction.
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10 10' 10DIAMETER IN M1CRONS 1. The normalized refractory-chain activity concentrations from coral surface explosions are relatively insensitive to yield, and, indeed, to particle size between about 50 n and 250n in diameter.
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15 Mt (Radioactive Particles Only, Shot Atoll, Spheres plus Irregulars) 0.04 Mt (All Particles, Shot Atoll, Spheres plus Irregulars)
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Advection and diffusion of radioactivity in the ocean is discussed in detail in Chapter 4. Fractionation of fission products created in underwater detonations is not severe (Freiling and Ballou, 1962)
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16 Radioactivity in the Marine Environment O GR0UND ZER0 ..-0.03 H + 48 H0URS 20 M1 ...- 0,4 0.04; °.4p'.04 H + 87 H0URS .013 H + 105 H0URS .0013 H + 537 H0URS FIGURE 4 Subsurface pattern of distribution of radioactivity from a nominal-yield underwater explosion as measured by an in situ gamma probe (some lines are dashed for clarity of presentation)
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. For underwater explosions, release to the seawater would include late-condensing soluble fission products and colloidal particles bearing most of the activity.
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18 Radioactivity in the Marine Environment TABLE 6 Radionuclide Distributions 31 hr after Detonation in Lagoon Burst; H + 2 Surface Water Sample Radionuclide "Total rare earths. Fraction Distribution Solid Phase Colloidal Phase Soluble Phase 89Sr 0.00 ± 0.00 0.11 ± 0.01 0.99 ± 0.00 95Zr 0.38 ± 0.01 0.16 0.03 ± 0.00 95Nb 0.45 ± 0.00 0.39 ± 0.01 0.00 ± 0.00 "Mo 0.28 ± 0.00 0.06 ± 0.01 0.60 ± 0.00 103Ru 0.60 0.25 ± 0.00 132Te 0.60 ± 0.00 0.1 8 ±0.00 l^Ba 0.00 ± 0.00 0.01 ± 0.01 0.99 ± 0.01 TRE" 0.83 ± 0.02 0.14 ± 0.06 0.03 ± 0.00 237u 0.02 ± 0.00 0.11 ±0.01 0.04 ± 0.06 "9Np 0.47 ± 0.00 0.46 ± 0.01 0.02 ± 0.00 additional membrane on the physical state distribution and on the mass balance observed.
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From page 19... ...
There is substantial evidence that this can be assumed with some confidence for 137Cs; hence, the 90Sr values of Table 8 can be converted to 137Cs values by multiplying by the constant 1.5. Calculation of amounts of other relatively long-lived fission products, such as 144Ce and 95Zr, from 90Sr ratios should be used with caution and must be TABLE 7 Worldwide Production and Deposition of 90Sr (in MCi)
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From page 20... ...
Second, the radioactivity produced per megaton of explosive force will be substantially reduced by employing explosives with low fission yields, by using nonactivating neutron absorbers to reduce the neutron activation of components of the explosive and of the soil, and by using explosive components whose activation products are of low biological significance. Finally, because low-fission-yield devices will be employed, activation products will equal or surpass fission products in curies produced and in biological significance.
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From page 21... ...
Sources of Radioactivity and Their Characteristics 21 TABLE 8 Annual Deposition of 90Sr Since 1958, by 10° Bands of Latitude (in MCi) Latitude 1958 1959 1960 1961 1962 1963 1964 1965 1966 Total 80° -90° N 0.003 0.002 0.001 0.001 0.002 0.007 0.002 0.001 0 0.019 70° -80° 0.025 0.016 0.006 0.006 0.017 0.047 0.014 0.008 0.003 0.142 60° -70° 0.064 0.059 0.011 0.020 0.089 0.200 0.087 0.030 0.012 0.572 50° -60° 0.114 0.157 0.031 0.044 0.168 0.376 0.262 0.109 0.042 1.293 40° -50° 0.153 0.206 0.043 0.065 0.285 0.540 0.354 0.149 0.056 1.851 30° -40° 0.147 0.218 0.043 0.064 0.247 0.358 0.248 0.137 0.051 1.513 20° -30° 0.106 0.192 0.038 0.045 0.214 0.358 0.239 0.091 0.034 1.317 10°-20° 0.024 0.104 0.035 0.035 0.145 0.250 0.180 0.094 0.036 0.903 0°-10° 0.019 0.021 0.025 0.031 0.113 0.184 0.093 0.069 0.026 0.581 0°-10° S 0.044 0.034 0.024 0.021 0.096 0.063 0.073 0.039 0.015 0.409 10° -20° 0.041 0.023 0.018 0.017 0.028 0.033 0.036 0.028 0.011 0.235 20° -30° 0.055 0.031 0.027 0.044 0.048 0.056 0.068 0.062 0.024 0.415 30° -40° 0.067 0.032 0.022 0.033 0.032 0.050 0.075 0.068 0.026 0.405 40° -50° 0.030 0.022 0.028 0.024 0.036 0.049 0.076 0.071 0.027 0.363 50° -60° 0.018 0.015 0.017 0.015 0.017 0.023 0.032 0.026 0.010 0.173 60° -70° 0.010 0.007 0.008 0.008 0.009 0.012 0.016 0.012 0.005 0.087 70° -80° 0.004 0.002 0.003 0.003 0.003 0.004 0.005 0.005 0.002 0.031 80° -90° 0 0 0 0 0 0 0.001 0.001 0 0.002 Total 0.924 1.141 0.380 0.476 1.549 2.610 1.851 1.000 0.380 10.311 TABLE 9 Deposition of 55Fe from Weapons Tests, by 10° Bands of Latitude (in MCi of 55Fe, decay corrected to October 15, 1961)
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From page 22... ...
The sum of activation products airborne in the radioactive cloud and in the fallout may be expected to be as low as the amounts shown in the following table: Representative Set of Induced Radioactivities at Detonation Time (Total in Cloud and Fallout) Nuclide Production, Kilocurie for Yield of Nuclide 100 KT 1 MT 10 MT 24Na 200 800 2,000 32,, 0.1 0.4 0.8 0.01 0.03 0.06 54Mn 0.1 0.3 0.7 56Mn 6,000 20,000 50,000 55 Fe 0.04 0.15 0.3 59 Fe 0.04 0.15 0.3 185W 6 10 14 187W 300 500 700 203Pb 1,000 7,000 20.000 Other 15 20 40 NUCLEAR REACTORS Nuclear reactors have been designed and built for a variety of purposes, as indicated by Table 1.
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From page 23... ...
However, some neutrons do escape from the core to interact with impurities in the coolant and with the reactor vessel and other nearby materials. The neutron activation products in the coolant are the major source of radioactive wastes in reactor operations.
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Radionuclides found in the coolant waters, and subsequently in the solid wastes, include most of the fission products and activated corrosion products such as 3H, 32P, siCr, 59Fe, 54Mn, 58Co, 60Co, 65Zn, 110mAg, 131I, 134mCs, 137Cs, 138Cs, 139Ba,and140Ba. DISPOSAL PROCEDURES If low in activity, liquid wastes are generally diluted with condenser cooling water to below 10~7 mCi/cc and discharged from the plant.
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Alan Preston, of the Ministry of Agriculture, Fisheries and Food of the United Kingdom, summarized in a private communication the annual liquid radioactive waste discharges of eight nuclear power stations operating in the United Kingdom in 1966, as shown in Table 12. ing the Pacific Ocean are as indicated in Table 14.
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Concentration ranged MCi Percent of limit Tritium, Ci/year (estimate Percent of limit (estim Solid wastes: Average annual volume and activity* Resins flAfter Blomeke and Harrington, *
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Solid radioactive wastes are transferred to shore facilities, packaged, and shipped to land burial sites.
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Nuclide Maximum Average Corrosion Products ISp 2.7 X 10'2 1.5 X 10-2 MNa 6.2X10^* 2.2 X 10-4 51Cr 3.4 X 10"3 3.7 X l0"4 56Mn 9.3 X 10-2 2.1 x 1o-2 59Fe 2.7 X10-3 5.1 x 1o-4 «>Co 2.5 X 10-2 3.2 X l0"3 MCu 4.7 X 10"3 1.0 X 10"3 65Ni 1.5 X I0"3 5.7 x io-4 182Ta 2.9 X 10-2 4.5 X l0'3 187W 9.0 X I0'3 1.5 x io-3 Fission Products ^Sr 5.0 X 10"6 ^Sr 5.0 X l0"8 131, 1.0 X 10•s 140Ba l.o x irr6 137Cs 1.0 Xl0'8 l^Ce 1.0 XI0'7 Civilian Propulsion Reactors As of 1970, there were only two operational nuclear-powered civilian ships-the United States' NS Savannah, a cargopassenger vessel, and West Germany's Otto Hahn, a 15,000ton bulk carrier, which was undergoing sea trials.
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From page 30... ...
In SNAP terminology, even numbers denote nuclear reactor units, and odd numbers, isotopic-heat-generating units. ated for a year, it would have accumulated approximately 40,000 Ci of fission products.
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From page 31... ...
. The fuel lattice retained about 99 percent of the available fission products.
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From page 32... ...
The source of energy for the SNAP devices are the longlived fission products or trans-uranics recovered from the tank-stored first-stage wastes from the processing of the irradiated fuel elements. These are first concentrated and then converted metallurgically to a dense mass most suitable for SNAP units.
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From page 33... ...
Sources of Radioactivity and Their Characteristics 33 TABLE 19 Characteristics and Applications of Oceanic SNAP Systems Power Electrical System Output Fuel Form Fuel Quantity (kCi) Marine Application Status as of November 1968 Past and Present Systems SNAP-7A 10W SNAP-7B 60 W SrTiO3 SrTiO3 41 225 Coast Guard buoy CG lighthouse; then, offshore Post test analysis after 3-yr operation Operating (relocated on oil platSNAP-7D 60 W SrTiO, 225 oil platform Navy NOMAD buoy, Gulf of Mexico form in August 1966 after 2 yr on lighthouse)
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From page 34... ...
2. Particle size of the stratospheric 238Pu from the SNAP-9A generator probably ranged from 5 to 58 mp in diameter, with the arithmetic mean at 9.7 m/u.
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-must be developed. PACKAGED RADIOACTIVE WASTE DISPOSAL Any establishment working with radioactive materials probably evolves radioactive wastes, since anything the radioactive material comes into contact with is likely to become contaminated -- i.e., some of the radioactive material is rubbed off or left behind.
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From page 36... ...
Alpha curies as a rule indicate thorium, uranium, or plutonium wastes, the isotopes having long half-lives. In 1967, the European Nuclear Energy Agency coordinated a waste disposal demonstration "experiment" to establish common sea disposal operation principles and safety practices.
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Sea Disposal Operations, 1946-1966 (Pacific Ocean) Year Approximate Location No.
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cRelatively low-activity wastes, including some from C.E.N.-Belgium and from Belchim, Belgium, disposed in the "Hurd Deep", an area near 50° N 01° W, by the United Kingdom. TABLE 25 Summary of European Nuclear Energy Agency Packaged Radioactive Waste Disposal Country of Origin Number of Containers Estimated Activity (Ci)
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1968. Management of radioactive wastes at nuclear power stations.
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769-785. In Proceedings of the conference on disposal of radioactive wastes into seas, oceans, and surface waters.
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From page 41... ...
1959. Considerations for the disposal of radioactive wastes from nuclear-powered ships into the marine environment.
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