United States Environmental Protection Agency Industrial Environmental Research Laboratory Research Triangle Park NC 27711 EPA-600/7-78-185 September 1978 Analysis for Radionuclides in SRC and Coal Combustion Samples nteragency Energy/Environment R&D Program Report ------- RESEARCH REPORTING SERIES Research reports of the Office of Research and Development, U.S. Environmental Protection Agency, have been grouped into nine series These nine broad cate- gories were established to facilitate further development and application of en- vironmental technology. Elimination of traditional grouping was consciously planned to foster technology transfer and a maximum interface in related fields. The nine series are: 1. Environmental Health Effects Research 2. Environmental Protection Technology 3. Ecological Research 4. Environmental Monitoring 5. Socioeconomic Environmental Studies 6. Scientific and Technical Assessment Reports (STAR) 7. Interagency Energy-Environment Research and Development 8. "Special" Reports 9. Miscellaneous Reports This report has been assigned to the INTERAGENCY ENERGY-ENVIRONMENT RESEARCH AND DEVELOPMENT series. Reports in this series result from the effort funded under the 17-agency Federal Energy/Environment Research and Development Program. These studies relate to EPA's mission to protect the public health and welfare from adverse effects of pollutants associated with energy sys- tems. The goal of the Program is to assure the rapid development of domestic energy supplies in an environmentally-compatible manner by providing the nec- essary environmental data and control technology. Investigations include analy- ses of the transport of energy-related pollutants and their health and ecological effects; assessments of, and development of, control technologies for energy systems; and integrated assessments of a wide range of energy-related environ- mental issues. REVIEW NOTICE This report has been reviewed by the participating Federal Agencies, and approved for publication. Approval does not signify that the contents necessarily reflect the views and policjes of the Government, nor does mention of trade names or commercial products constitute endorsement or recommendation for use. This document is available to the public through the National Technical Informa- tion Service, Springfield, Virginia 22161. ------- EPA-600/7-78-185 September 1978 Analysis for Radionuclides in SRC and Coal Combustion Samples by Pamela A. Koester and Warren H. Zieger Hittman Associates, Inc. 9190 Red Branch Road Columbia, Maryland 21045 Contract No. 68-02-2162 Program Element No. EHE623A EPA Project Officer: William J. Rhodes Industrial Environmental Research Laboratory Office of Energy, Minerals, and Industry Research Triangle Park, NC 27711 Prepared for U.S. ENVIRONMENTAL PROTECTION AGENCY Office of Research and Development Washington, DC 20460 ------- TABLE OF CONTENTS Page 1. SUMMARY 1 2. INTRODUCTION 3 3. SAMPLE COLLECTION AND ANALYSIS 6 4. DATA ANALYSIS 10 5. ESTIMATED RADIONUCLIDE EXPOSURE LEVELS 24 REFERENCES 27 iii ------- 1. SUMMARY This report deals with the determination of the levels of uranium, thorium, and their daughter products in coal, SRC, coal flyash, and SRC flyash samples taken from Georgia Power Company's Plant Mitchell during the May and June 1977 combustion tests to compare the environmental emissions from the use of coal and SRC in the boilers. Gross alpha and beta activities were also measured in the samples. Uranium and thorium were observed to be present at concentrations ranging from 0.8 to 39 ppm and 3.7 to 20 ppm, respectively. Calculated levels of other radionuclides in secular equilibrium with uranium and thorium were found to range from 7.4x10" ppm to 1.0x10 ppm. Quantitative alpha measurements could not be made due to the self absorp- tion of the alpha particles in the samples. Beta measure- ments, however, could be taken and were found to be on the 12 order of 50 pCi/gm. (A pCi is 10 curies. A curie is a basic unit for measurement of radioactivity, equaling 3.7x10 nuclear transformations per second). Levels of radionuclides in the samples were also com- pared with reported levels of uranium and thorium in coal and SRC and with estimated emissions from coal fired power plants. Uranium and thorium levels in the samples were found to be of the same order of magnitude as those reported in the literature. Data obtained from Plant Mitchell and other coal fired power plants, as well as data obtained in ------- this report, were used to estimate the level of uranium-238 which may be discharged from a power plant. The estimated 3 level was found to be 0.2 yg/m which is lower than allowed 3 general public dose radiation levels of 7.0 ug/m . This leads one to conclude that the radionuclide levels present in the tested samples do not appear to pose any significant problem from a radiotoxic standpoint. Further analysis of various types of coal and SRC products is recommended, however, before this may be concluded on an overall basis. ------- 2. INTRODUCTION There are three major distinct chains of radioactive elements contained in essentially all coals: (1) the uranium series which originates with uranium-238; (2) the thorium series which originates with thorium-232; and (3) the actinium series which originates with uranium-235. These three elements decay into a number of radioactive species which are important from a radiotoxic standpoint. The decay process is a process of transformation of radioactive ele- ments to other elements. This transformation is acompanied by emisson of alpha or beta particles and gamma radiation. When a radioactive element decays, a new radioactive element is born which itself is subject to decay. The uranium, thorium and actinium decay series are shown in Figure 1. Since the first member of each decay series has a relatively long half-life when compared to the other members, a steady- state condition is established which is known as "secular" equilibrium. This steady-state condition allows one to calculate the concentration of each of the daughter radio- nuclides. Those elements of most importance include thorium- 230, radium-226, radon-222, lead-210, polonium-210, radium- 228, thorium-228, and radon-220. The concentrations of elements within these decay chains may vary significantly from one coal to the next. It has been observed that eastern coals generally contain about 1.6 ppm uranium and 2.0 ppm thorium although individual values may vary considerably (2). Western coals have been ------- DO ' C - - - u ~ I 144 -— ^-t- 78 80 82 84 86 88 90 92 94 Hg Tl Pb Bi Po Ai Rn Fr Ka Ac Th Ha U Atomic Number 78 80 82 84 86 88 90 92 94 Hg Tl Pb Bi Po At Rn Fr Ra Ac 1h Pa U Atomic Number 78 80 82 84 86 88 90 92 94 Hg Tl Pb Bi Po Ai Rn Fr Ra Ac Th Pa U Atomic Number Figure 1. Radioactive Decay Chains (1) ------- reported to contain much higher concentrations ranging from 10 to greater than 5000 ppm (3). The concentrations of uranium-238, uranium-235 and thorium-232 naturally affect the levels of other radionuclides within the three chains as they are all considered to be in secular equilibrium with each element within their respective chains. It has been observed in coal and SRC processing opera- tions that radionuclides are most likely to be found in solid residues and flyash (4). Smaller quantities may be found in gaseous and liquid wastes. These operations tend to concentrate the radionuclides thereby possibly posing some occupational health hazards. This report examines the levels of several radionuclides in various coal and coal product samples and the significance of these levels from a radiotoxic standpoint. Also, the measurement of numerous radionuclides in the SRC samples is especially significant in view of the fact that the SRC samples were obtained from the first commercial coal fired facility ever to use SRC in a full scale comprehensive combustion test program. ------- 3. SAMPLE COLLECTION AND ANALYSIS 3.1 Sample Collection Samples were collected from combustion tests performed at Georgia Power Company's Plant Mitchell during the summer of 1977 (5). At this installation, both Kentucky coal and SRC solid fuel were individually burned in a pulverized coal-fired boiler to determine if SRC could replace coal as a primary fuel. A Source Assessment Sampling System (SASS) train analysis was performed on the stack gases from the boilers. A typical train is shown in Figure 2. Samples analyzed for radionuclides in this report were taken from the 10-micron, 3-micron, and 1-micron cyclones, and from the filters of coal Run No. 1 on 5/25/77 and SRC Run No. 2 on 6/17/77. Two sets of coal, SRC solid fuel, coal particulate, and SRC particulate samples were analyzed. 3.2 Sample Preparation In order to prepare the coal and SRC solid fuel samples for analysis, it was first necessary to pulverize and ash them to remove all available carbon. This step facilitated the subsequent sample digestion process. Coal and SRC particulate samples were also ashed and digested prior to analysis after a specific homogeneous mixture of particulate ------- STACK T.C. HEATER CON- TROLLER CONVECTION OVEN r~ FILTER , /^x-1 SS PROBE* | |- 1 1 1 JIJ GAS COOLER DRY GAS METER ORIFICE METER CENTRALIZED TEMPERATURE AND PRESSURE READOUT CONTROL MODULE GAS TEMPERATURE T.C. XAD-2 CARTRIDGE IMP/COOLER TRACE ELEMENT COLLECTOR CONDENSATE COLLECTOR 10 CFM VACUUM PUMP IMPINGER T.C. Figure 2. Source Assessment Sampling System (5) ------- matter had been obtained. The weights of cyclone and filter particulates used in the analysis are given in Table 1 along with the coal and SRC sample weights. The samples used to determine gross alpha and beta activities were only pulverized prior to analysis. The weight percentage of cyclone and filter particulate matter was similar to that shown in Table 1. 3.3 Sample Analysis Levels of uranium, thorium, and gross alpha and beta activities were measured in all coal, SRC solid fuel, coal particulate and SRC particulate samples. Levels of uranium were measured using techniques based on the U.S. Geological Survey Fluorimetric Methods of Uranium Analysis (15). Melts obtained by fusing uranium salts with sodium fluoride fluor- esce a brilliant yellow green when exposed to ultraviolet light. The intensity of the fluoresence is proportional, within wide limits, to the amount of uranium present, and this relationship is the basis for the quantitative fluori- metric determination of uranium. A standard colorimetric test - ASTM D2333-68, was used to determine the levels of thorium in the selected samples (6). Alpha and beta activ- ities were measured using a Baird Atomic Model 530 Spectro- meter with a 2-inch gas flow proportional detector having an ultra-thin window ( 100 mg/cm3). In order to detect the presence of any uranium and thorium daughter products, gamma ray activities were measured using a Baird Atomic Model 530 Spectrometer with a 1.75 inch x 2 inch thick Nal (TI) scin- tillation detector. 8 ------- TABLE 1. WEIGHT DISTRIBUTION OF SAMPLES ANALYZED (Grams) Composite 10- Cyclone Coal Particulates #1 0.03750 n 0.037385 SRC Particulates #1 0.5719 //2 0.5719 Coal #1 #2 SRC //I #2 3- Cyclone 1- Cyclone Filters Total 0.29040 0.28090 0.05540 0.6641 0.29020 0.28100 0.05550 0.664085 0.1902 0.0106 0.2312 1.0039 0.1901 0.0103 0.2294 1.0017 2.0036 2.0051 2.0041 2.0115 ------- 4. DATA ANALYSIS 4.1 Analyses by Fluorimetric Methods 4.1.1 Summary of Analyses Table 2 lists the results of the uranium and thorium analyses. From these values, the concentrations of their daughter products were calculated assuming they are in secular equilibrium with their respective parent, and mea- sured uranium is 99.27 percent uranium-238 (natural uranium contains this percentage of uranium-238). Calculated con- centrations of uranium, thorium, and their daughter products of particular interest from a radiotoxic standpoint and/or with long half-lives are given in Table 3. 4.1.2 Discussion of Data Several observations may be made based on the results of the laboratory analyses: (1) Uranium levels were found to be less than thorium in all cases but the SRC parti- culates. (2) Uranium and thorium were more concentrated in the SASS train particulate samples than in the coal and SRC solid fuel. (3) The limited data do not allow one to predict any trends in the increase of uranium, thorium, and their daughter products in the particulate 10 ------- TABLE 2. RADIONUCLIDE CONCENTRATIONS (ppm by weight) Source Coal Sample #1 Sample #2 SRC Sample #1 Sample #2 Coal Particulates Sample #1 Sample #2 SRC Particulates Sample #1 Sample #2 Uranium 1.3 1.4 0.8 1.3 2.6 1.9 39 28 Thorium 4.74 4.24 4.99 3.73 14.99 20.50 11.46 9.48 11 ------- to TABLE 3. CALCULATED LEVELS OF RADIONUCLIDES IN COAL AND COAL PRODUCTS (ppm by weight) Product/Source u238 Th234 u234 Th230 Ra226 Rn222 Bi210 Po210 Th232 Ra228 Th228 Ra224 „ 220 Rn 235 u Th231 pa239-231 A 227 Ac 227 Til _, 223 Ra Pb211 Coal 1.29-1.39 1.9-2.04xlO~11 7. 0-7. 54x1 0~5 2.1-2.3xlO~5 4.4-4.7xlO~7 2.8-3.0xlO~12 3.4-3.7xlO~12 9.6-10.3xlO~U 4.24-4.74 1.73-1.94xlO~9 0.57-.64xlO~9 2.8-3.2xlO~12 5-5.7xlO~16 0.009-0.01 3.7-4.0xlO~13 4.2-4.5xlO~6 2.6-2.8xlO~9 6.1-6.5xlO~12 3.7-4.0xlO~12 1.14-1.23xlO~16 SRC 0.79-1.29 1.16-1.25xlO~n 4. 3-4. 6x1 0~5 1.3-1. 4x1 0~5 2.7-2.9xlO~7 1.7-1.85xlO~12 2.3-2.44xlO~12 5.9-6.4xlO~U 3.73-4.99 1.7-2.99xlO"9 0.56-0.75xlO~9 2.8-3.8xlO~12 5-6.8xlO~16 0.006-0.009 2.3-3.7xlO~13 2. 6-4. 2x1 0~6 1.6-2. 6x1 0~9 3.8-6.1xlO~12 2.4-3.7xlO~12 0.74-1.14xlO~16 Coal Particulate 1.88-2.58 2.77-3.8xlO~U 10.2-14xlO~5 3. 0-4. 2x1 0~5 6.4-8.8xlO~7 4.1-5.6xlO~12 5.4-7.4xlO"12 19.2-14.0xlO~U 14.99-20.5 6.9-9.3xlO~9 2.3-3.0xlO~9 11.5-15xlO"12 20.7-27xlO~16 0.014-0.02 5.4-7.7xlO"13 6.1-8.8xlO"6 3.8-5.5xlO~9 8.9-12.8xlO~12 5. 5-8. Oxl O"12 1.7-2.5xlO~16 SRC Particulate 27.8-38.7 4.10-5.72xlO~U 15-21xlO~5 4.5-6.3xlO~5 9.5-13.3xlO~7 6.0-8.4xlO~12 8.0-ll.lxlO~12 20.6-28.9xlO~U 9.48-11.46 4.4-5.3xlO~9 1.4-1.7xlO~9 7-8.5xlO~12 12.6-15.3xlO~16 0.20-0.30 77-lllxlO~13 87-126xlO~6 54-79xlO~9 126-185xlO~12 78-115xlO~12 24-35xlO"16 ------- samples, whether the radionuclides are more heav- ily concentrated in SRC flyash as opposed to coal flyash, or what percentage of the radionuclides pass from coal to SRC since the coal is not known to be the same coal from which the SRC was pro- duced. Literature has indicated, however, that at least 90 percent of the uranium is expected to be retained in the bottom ash and collected flyash (4). 4.1.3 Variation Within Data Uranium levels were measured in duplicate samples by uranium fluorimetric analysis to determine whether the fluctuation between pairs of results was real or due to inadequacies in the method. The variance and standard deviation of the paired results were found to be 1.37 per- cent and 1.22 percent, respectively. This leads one to conclude that the differences in the reported values are not due to laboratory procedures but rather to nonhomogeneous samples. This is expected to be similar for the thorium results. Efforts were also made to compare the observed levels of uranium and thorium in coal and SRC samples with those reported in the literature. Figures 3 and 4 give some indication of the wide range of uranium and thorium levels which may be found in coal. The data from the Eastern United States are plotted as unpatterned bars, those from the Illinois Basin as vertically striped bars, and those from the Western United States as horizontally striped bars. Table 4 provides reported data collected on levels of uran- ium and thorium in different types of samples. 13 ------- a •• i- 0.0 2.0 1.0 10.0 21 2 '• IS 0.0 1. S i 6 I (PPM) u IPPM Figure 3. Distribution of Thorium in coals analyzed (7) Figure A. Distribution of Uranium in coals analyzed (7) Note: Unpatterned bars - Eastern United States Vertical striped bars - Illinois basin Horizontal striped bars - Western United States ------- TABLE 4. LEVELS OF URANIUM AND THORIUM IN COAL AND RELATED PRODUCTS (ppm by weight) Coal Boiler Precipitator Mineral Location Coal Flyash Residue Collected Ash SRC Residue Uranium Navajo Mines (4)c 2.56 Rocky Mt. Area (4)c 0.69 -- 6.78 9.4 S. Illinois (4)c 2.18 -- 14.9 30.1 Four Corners,NM (4)° -- -- 9.77 9.8 Illinois (8)c 1.1-4.2 General (9)b 1.41-1.53 11.6-11.9 Kentucky <10)a 1.1 — — -- 0.54 .73 Thorium Kentucky (10)c 1.9 Illinois (8)c 3.1-8.0 General (9)b 3.0-6.5 26.1-30.4 — — 0.19 10.0 aNeutron Activation Analysis Delayed Neutron Determination X-ray Fluorescence ------- The coal samples analyzed in this project origi- nated from Kentucky while the SRC samples originated from the processing of Illinois coal. Average levels of uranium and thorium reported in the literature for Illinois coals are 1.5 and 2.1 ppm, respectively (7). Average levels of uranium and thorium reported for Kentucky coals are 1.85 and 2.6, respectively (7). The reported levels of these radio- nuclides are not significantly different between the two types of coal. If we assume the coal samples contain approxi- mately 10 percent ash and allow the variable "X" to repre- sent the quantity of coal processed (in gm/day), then the quantities of uranium and thorium observed in the analyzed samples may be summarized as shown in Table 5. TABLE 5. LEVELS OF URANIUM AND THORIUM IN COAL SAMPLES (Ug/day)' Sample Uranium Thorium Coal Sample 1 1.3X 4.7AX Coal Sample 2 1.4X 4.24X Coal Sample 1 Particulates 0.03X 1.50X Coal Sample 2 Particulates 0.02X 2.05X 16 ------- For all samples, the quantities of uranium and thorium in the particulate samples were found to be lower than in the coal samples. This observation correlates well with the literature where it has been suggested that uranium and thorium are partitioned between the flyash, bottom ash, liquid streams, and, in the case of coal liquefaction processes, in the final SRC product. If we assume the SRC to contain, on the average, 0.1 percent ash and allow the variable "Y" to represent the quantity of SRC combusted (in gin/day) , then the quantities of uranium and thorium observed in the analyzed samples (in micrograms/day) may be summarized as shown in Table 6. TABLE 6. LEVELS OF URANIUM AND THORIUM IN SRC SAMPLES Sample SRC Sample SRC Sample SRC Sample SRC Sample (ug/day) Uranium 1 0.8Y 2 1.3Y 1 Particulate 0.04Y 2 Particulate 0.03Y Thorium 4.99Y 3.73Y 0.01Y 0.009Y In all instances, the total quantity of uranium and thorium present in the particulate samples appears to be significantly less than the levels observed in the SRC samples. This leads one to conclude that the uranium and thorium is being partitioned more heavily into other process constituents. 17 ------- Although this analysis appears to indicate that the total quantities of uranium and thorium are smaller in the flyash samples, the variable and limited data do not allow one to conclude that this is the general trend which should be observed in all cases. This is especially evident in view of the fact that bottom ash samples could not be analyzed to substantiate reported literature observations that 90 percent of the uranium and thorium should be re- tained in the bottom and flyash (A). Assuming the following data for the combustion of SRC Run No. 2 on June 17, 1978 (data collected during plant visit). Fuel Flow - 8.060 kg SRC/hr. SASS Sample Volume - 28.5 m3 Gas Flow - 3,620 m3/minute Weight of SRC particulates per sample volume - 1.0017 gm Uranium concentrations in: SRC - 1.3 ppm SRC particulates - 28 ppm Thorium concentrations in: SRC - 3.7 ppm SRC particulates - 9.5 ppm 18 ------- Weight of SRC = 362° S x £0_jnin x 1 Sample x 1.0017 8tn Particulates/Hr min hr 28.5 m 1 sample = 7634 gtn/hr Weight of Uranium = 7634 ^ x ^ =0.214 gm/hr in particulates hr 1,000,000 Weight of Uranium = 8,060,000 gm x 1_3 = 1Q 48 in SRC feed hr 1,000,000 % Uranium not = 1Q'48 " °-2U x 100 = 98 in Particulates 10.48 As shown above, the percentage of uranium not in the particulates was calculated to be approximately 98 per- cent of the total uranium in the SRC feed. Similar calcu- lations for thorium show greater than 99 percent of total thorium not in the particulates. It is unfortunate that no samples were taken during the Plant Mitchell runs of the bottom ash. Therefore, there is no way to verify or re- fute this indicated bottom ash radioactivity concentration. Table 7 lists the observed sample means (x) and the means of the literature values (y). On an absolute basis, the observed sample means correlate well with the means of the literature values and are of the same general order of magnitude. 4.2 Uranium Analysis by Atomic Absorption Efforts to measure the levels of uranium in the samples were unsuccessful. Limits of detectability for uranium were found to be on the order of 50 ppm. 19 ------- TABLE 7. EVALUATION OF SAMPLE DATA (ppm by weight) Source Coal Uranium Thorium SRC Uranium Thorium Coal Particulates Uranium Thorium SRC Particulates Uranium Thorium Observed Data (x) 1.4 4.5 1.0 4.4 2.2 17.8 33.5 10.5 Literature Data 1.0 (7) 2.0 (7) 0.5 (10) 0.2 (10) 11.8 (9) 28.0 (9) 7.0 (10) 10.0 (10) 20 ------- 4.3 Gross Alpha and Beta Activities 4.3.1 Summary of Analyses Alpha and beta activities were measured in all the samples listed in Table 1. Radiation was qualitatively detected in all samples, but only quantitatively measured for the coal and SRC solid fuel particulate samples. Alpha radiation could not be determined due to self absorption of the alpha particles in the samples. Results of the beta analysis in coal and SRC particulate samples are given in Table 8. Expected levels of selected radionuclides are given in Table 9. TABLE 8. BETA ACTIVITIES OF COAL AND SRC SAMPLES Source Coal Coal Flyash SRC SRC Flyash Weight (gtn) 1.945 0.678 1.842 0.208 Activity (pCi) BD 17.2 BD 12.3 Activity Concentration (pCi/gm) BD 25.0 BD 59.0 BD = Below Detection 4.3.2 Discussion of Data Photo-peak analysis was used in an attempt to confirm and identify the presence of uranium and thorium daughter products. The 239 KeV gamma ray of lead-212 (thor- ium- 232 daughter) and the 609 KeV gamma ray of bismuth-214 (uranium-238 daughter) were selected because of their high 21 ------- TABLE 9. EXPECTED RADIONUCLIDE ACTIVITIES (pCi/gm) Product /Source u238 Th23A u23A Th230 Ra226 Rn222 Bi21° Po210 232 Tli „ 228 Ra „ 224 Ra Rn22° u235 Th231 Pa231 Ac227 Th227 Ra223 Pb211 Coal 0.004 0.004 0.004 0.004 0.004 0.004 0.004 0.004 0.004-0.005 0.004-0.005 0.004-0.005 0.004-0.005 0.002 0.002 0.002 0.002 0.002 0.002 0.002 SRC 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.004-0.005 0.004-0.005 0.004-0.005 0.004-0.005 0.001-0.002 0.001-0.002 0.001-0.002 0.001-0.002 0.001-0.002 0.001-0.002 0.001-0.002 Coal Particulates 0.006-0.008 0.006-0.008 0.006-0.008 0.006-0.008 0.006-0.008 0.006-0.008 0.006-0.008 0.006-0.008 0.017-0.023 0.017-0.023 0.017-0.023 0.017-0.023 0.003-0.004 0.003-0.004 0.003-0.004 0.003-0.004 0.003-0.004 0.003-0.004 0.003-0.004 SRC Particulates 0.008-0.012 0.008-0.012 0.008-0.012 0.008-0.012 0.008-0.012 0.008-0.012 0.008-0.012 0.008-0.012 0.011-0.013 0.011-0.013 0.011-0.013 0.011-0.013 0.04 -0.06 0.04 -0.06 0.04 -0.06 0.04 -0.06 0.04- 0.06 0.04 -0.06 0.04 -0.06 22 ------- yields. The spectrometer was set up to window in on these energies. Concentrations of these elements were too low to measure using this method. The low levels of radionuclides observed in these samples correlate with the calculated levels listed in Tables 3 and 4. The summations of calculated beta radiation levels resulting from the presence of uranium, thorium, and their daughter products were found to be much lower than those recorded by the spectrometer. Possible explanations for this observation include: incorrect counting efficiency, interference from radionuclides other than those of specific interest, and levels of radiation being at the threshold of detection limits as was the case for the atomic absorption unit. 23 ------- 5. ESTIMATED RADIONUCLIDE EXPOSURE LEVELS The levels of observed and calculated radiation appear to be quite small. To give some indication of their small- ness, they may be compared to typical occupational and general public exposure levels given in Table 10 (3) . The following assumptions, based on data obtained from Plant Mitchell and other typical coal fired power plants, were used to estimate the levels of uranium-238 expected to be discharged from a power plant which combusts SRC solid fuel. (1) Stack gas particulates _ R A9 ,n-3 coal input °'^ x iu (2) Ash content of coal - 15.01% (11) (3) Expected ash content of SRC = 0.173 (12) (4) Stack gas particulates _ 0.1 ft ~3 SRC input 15.01 B (5) Stack gas _ Stack gas coal input SRC input = 183 scf/lb coal or SRC (avg) (13) (6) SRC load = 17,600 Ib/hr (Plant Mitchell tests) (14) (7) U238 = 0.9927 (U) 24 ------- TABLE 10 EXCERPTS FROM 10CFR20 STANDARDS FOR PROTECTION AGAINST RADIATION FOR MAJOR RADIONUCLIDES ASSOCIATED WITH COAL-BURNING FACILITIES Element (Isotope) "Occupational" Exposure Standard Air Water "General Public" Exposure Standard Air Water "Occupational" Exposure Standard Air Water yg/m^ umg/fc "General Public" Exposure Standard Air Water yg/m3 pmg/Jl Uranium Series Uranium (238) S I Thorium (234) Uranium (234) Thorium (230) Radium (226) Radon (222) Lead (210) Bismuth (210) 1,2 1,1 S T S I S I S T s3 S T S T Polonium (210) S I -7 x 10-11 1 x 10-10 6 x 10~8 3 x 10~8 6 x 10-10 1 x 10-10 2 x 10-12 1 x 10-11 3 x 10-U 5 x ID'11 3 x 10'8 1 x ID'10 2 x 10-10 6 x 10"9 6 x 10~9 5 x 10-10 2 x 10~L0 1 x 10~3 1 x 10~3 5 x 10-11 5 x 10~4 9 x 10"4 9 x 10~4 5 x 10"5 -4 9 x 10 4 x 10~7 9 x 10~4 4 x 10'6 5 x 10~3 1 x 10~3 1 x 10"3 2 x 10~5 8 x 10~4 3 x 10-12 5 x ID'12 2 x 10~9 1 x 10~9 2 x 10-11 4 x 10~12 8 x 10-14 3 x 10-13 3 x 10-12 2 x 1C'12 3 x 10~9 4 x 10~12 8 x 10-12 2 x 10-10 2 x 10-10 2 x 10-11 7 x 10-12 4 x 10~5 4 x 10"5 2 x 10"5 2 x 10"5 3 x 10"5 3 x 10~5 2 x 10'6 3 x 10~5 3 x 10'8 3 x 10~5 1 x 10~7 2 x 10~4 4 x 10"5 4 x 10~5 7 x 10~? 3 x 10~5 200 300 2.6 x 10~6 1.3 x 10~6 9.7 x 10~2 1.6 x 10"2 1 x 10~4 5 x 10"4 3 x 10~5 5 x 10~5 1.9 x 10~7 1.2 x 10~6 2.4 x 10~6 9 9 1.1 x 10~? 4.4 x 10"8 2. 2. 1. 1. 2. 4. 3 x 103 3 x 103 2 x 10~8 2 x 10~8 5 x 10 5 x 10'1 6 x 10~3 6 x 10~2 4 x 10~7 9 x 10~4 4.8 x 10"8 6.0 x 10~5 4 1 1.3 1.3 .4 x 10~9 .8 x 10~7 8. 4. 3. 6. 4. 1. 7 15 6 x 10~8 3 x 10"8 •j 2 x 10 5 x 10~4 1 x 10"6 5 x 10~5 £ 3 x lO'6 2 x 10'6 Q 1.9 x 10 " 4.8 x 10~8 9.6 x 10~8 4 1 0.3 0.3 .4 x 10~ .5 x 10~9 1.2 x 10 1.2 x 10 8.6 x 10~10 8.6 x 10~10 3 4.8 x 10 4.8 x 10~3 A 1 x 10 1.5 x 10"3 _ 0 3 x 10 8 1 x 10~5 1.2 x 10~9 2.3 x 10~6 _9 6.1 x 10 , -2 6.1 x 10 _i n 1.6 x 10 1U 6.8 x 10~9 ------- (8) U = 33.5 ug/gm particulate SRC (data from this report) U238 discharged = (5.6xlO"5)(1.76xl04)(33.5)(454)(0.9927) (183)(1.76xl()4)(0.028) U238 =0.2 yg/m3 This compares to the general standard of 7.0 yg/m and O is much less than an occupational exposure of 200 yg/m shown in Table 10 for uranium-238. Since this analysis has not included dispersion in the atmosphere, the actual levels which should be observed would be significantly less than 2 0.2 yg/m . The conclusion that the levels of uranium, thorium, and their daughter products which may be discharged are quite small has also been reported by other authors (3). This may not be the case, however, for coals with very high uranium and thorium contents. 26 ------- REFERENCES 1. Arya, A.P., Fundamentals of Nuclear Physics, Boston 1966. 2. Gluskoter, H.J., W.G. Miller, R.A. Cahel, R.R. Ruch, and M.F. Shimp, "An Investigation of Trace Elements in Coal," Illinois State Geological Survey, Urbana, Illinois. EPA-600/7-77-064, June 1977. 3. Battelle, Columbus Laboratories. Radionuclides from FBC Processes - Brief Technical Memo No. 3_, January 1977. 4. Los Alamos Scientific Laboratory. A Review of Trace Element Studies Related to_ Coal Combustion in The Four Corners Area of New Mexico. Los Alamos, New Mexico, July 1976. 5. Koralek, C.S. and May, V.B., "Flue Gas Sampling During the Combustion of Solvent Refined Coal in a Utility Boiler," In: Proceedings of EPA Symposium on Environmental Aspects of Fuel Conversion Technology, III, September 1977, Hollywood, Florida, EPA-600/7-78-063, Franklin Ayer, Compiler. 6. ASTM. 1976. Annual Book of ASTM Standards Part 31^ Water, ASTM 1976. 27 ------- 7. Illinois State Geological Survey. EPA-600/7-77-064. Trace Elements in Coal: Occurrence and Distribution. June 1977. 8. Los Alamos Scientific Laboratory. Trace Elements Characteriz at ion and Remoya1/Reco very from Coal and Coal Wastes, Los Alamos, New Mexico, October 1977. 9. EPA-NBS Interlaboratory Comparison for Chemical Elements in Coal, Flyash, Fuel Oil and Gasoline, May 1973. 10. Fruchter, J.S., J.C. Laul, M.R. Peterson, P.W. Ryan, and M.E. Turner. High Precision Trace Element and Organic Constituent Analysis of_ Oil Shale and Solvent- Refined Coal Materials. December 19, 1977. 11. Federal Power Commission. January 1976. Steam-Electric Plant Air and Water Quality Control Data. Washington, D.C. 12. Pittsburgh and Midway Coal Mining Co. Solvent Refined Coal Pilot Plant. 13. Radian Corp., September 1975. Coal Fired Power Plant Trace Element Study. Prepared for the EPA, Region VIII, Denver, Colorado. 14. Data obtained from the Plant Operator at Georgia Power Company's Plant Mitchell. 15. U.S. Department of the Interior. U.S. Geological Survey Fluorimetric Methods of Uranium Analysis. Geo- logical Survey Circular 199. 28 ------- TECHNICAL REPORT DATA (Please read Instructions on the reverse before completing) . REPORT NO. EPA-600/7-78-185 2. 3. RECIPIENT'S ACCESSION NO. 4. T.TUE AND SUBTITLE Analysis for Radionuclides in SRC and oal Combustion Samples 5. REPORT DATE September 1978 6. PERFORMING ORGANIZATION CODE 7. AUTHORIS) Pamela A. Koester and Warren H. Zieger 8. PERFORMING ORGANIZATION REPORT NO. . PERFORMING ORGANIZATION NAME AND ADDRESS littman Associates, Inc. 9190 Red Branch Road olumbia, Maryland 21045 10. PROGRAM ELEMENT NO. EHE623A 11. CONTRACT/GRANT NO. 68-02-2162 12. SPONSORING AGENCY NAME AND ADDRESS EPA, Office of Research and Development Industrial Environmental Research Laboratory Research Triangle Park, NC 27711 13. TYPE OF REPORT AND PE Final; 11/77 - 7/78 PERIOD COVERED 14. SPONSORING AGENCY CODE EPA/600/13 IB.SUPPLEMENTARY NOTES ffiRL-RTP project officer is William J. Rhodes, Mail Drop 61, 919/i U41-2851. 16.ABSTRACTThe report deals with the determination of the levels of uranium, thorium, and their daughter products in coal, Solvent Refined Coal (SRC), coal flyash, and SRC lyash samples from Georgia Power Co. Ts Plant Mitchell May and June 1977 combus- ion tests to compare the environmental emissions from the use of coal and SRC in the )oilers. Gross alpha and beta activities were also measured. Uranium and thorium concentrations ranged from 0.8 to 39 ppm and 3. 7 to 20 ppm, respectively. Calculated evels of other radionuclides in secular equilibrium with uranium and thorium ranged rom 7.4 x 10 to the minus 17th power to 0.0001 ppm. Alpha levels could not be quanti- ied due to the self absorption of the alpha particles. Beta levels, however, were on he order of 50 pCi/g. (A pCi is 10 to the minus 12th power curies; a curie is a basic inlt for measurement of radioactivity, equalling 3.7 x 10 to the 16th power nuclear ransformations per second.) Levels of radionuclides were also compared with repor- ed levels of uranium and thorium in coal and SRC and with estimated emissions from joal-fired power plants. Uranium and thorium levels were of the same order of magni- ude as those reported in the literature. Data from Plant Mitchell and other coal-fired jower plants, as well as data obtained in this report, were used to estimate the level >f uranium-238 that may be discharged from a power plant: the estimated level was ).2 micrograms/cu m. wfilch'is below the allowable public use level. . 7. KEY WORDS AND DOCUMENT ANALYSIS DESCRIPTORS b.lDENTIFIERS/OPEN ENDED TERMS c. COSATI Field/Group Pollution oal iquefaction ombustion hdustrial Processes Radioactive Isotopes Analysis Uranium Thorium Fly Ash Alpha Particles Beta Particles Pollution Control Stationary Sources Solvent Refined Coal Radionuclides 13B 21D 07D 21B 13H 18B MB_ 07B 20H 8. DISTRIBUTION STATEMENT Unlimited 19. SECURITY CLASS (This Report) Unclassified 21. NO. OF PAGES 33 20. SECURITY CLASS (Thispage) Unclassified 22. PRICE EPA Form 2220-1 (9-73) 29 ------- |