<> *^T* ,G^ <>, '" • » * A * ^. -: £°* ■&*"* a5°^ jPv\ o G u ♦*, ^^ ^ v ■H^ ^ 6 -0 * "<> <. *'T <* *- * • ■ 4V e »"« jP-TS <> *'"^T« .G* ^> • 4* ^ • ,♦".•• <* *'T ^°* o » o 4? •-•^* ^ ^^ • ■ ^0* V^> V-^V VW>* vwv vw/ V- i&\ /^\ /••;£&.% /.«•> /^ ^ IC 9257 BUREAU OF MINES INFORMATION CIRCULAR/1990 D300 j7 International Intercalibration and Intercomparison Program Radon Daughter Measurements Exercise at the Twilight Mine, Uravan, CO By W. E. Cooper and R. F. Holub U.S. BUREAU OF MINES 1910-1990 V YEARS a THE MINERALS SOURCE Mission: As the Nation's principal conservation agency, the Department of the Interior has respon- sibility for most of our nationally-owned public lands and natural and cultural resources. This includes fostering wise use of our land and water resources, protecting our fish and wildlife, pre- serving the environmental and cultural values of our national parks and historical places, and pro- viding for the enjoyment of life through outdoor recreation. The Department assesses our energy and mineral resources and works to assure that their development is in the best interests of all our people. The Department also promotes the goals of the Take Pride in America campaign by encouraging stewardship and citizen responsibil- ity for the public lands and promoting citizen par- ticipation in their care. The Department also has a major responsibility for American Indian reser- vation communities and for people who live in Island Territories under U.S. Administration. Information Circular 9257 International Intercalibration and Intercomparison Program Radon Daughter Measurements Exercise at the Twilight Mine, Uravan, CO By W. E. Cooper and R. F. Holub UNITED STATES DEPARTMENT OF THE INTERIOR Manuel Lujan, Jr., Secretary BUREAU OF MINES T S Ary, Director $ A Library of Congress Cataloging in Publication Data: Cooper, W. E. (Wade Emanuel), 1955- International intercalibration and intercomparison program radon daughter measurements. Exercise at the Twilight Mine, Uravan, CO / by W. E. Cooper and Robert F. Holub. p. cm. - (Bureau of Mines information circular; 9257) Includes bibliographical references. Supt. of Docs, no.: I 28.27:9257. 1. Mine gases-Colorado-Twilight Mine-Measurement. 2. Radon-Isotopes- Measurement. I. Holub, Robert F. II. Title. III. Series: Information circular (United States. Bureau of Mines); 9257. TN295.U4 [TN305] 622 s-dc20 [622'.82] 90-1743 CIP CONTENTS Page Abstract 1 Introduction 2 Acknowledgments 2 Measurement facilities and procedures 2 Results and discussion 5 Conclusions 12 References 12 Appendix-Participants 13 ILLUSTRATIONS 1. Plan map of the Twilight Mine 4 2. Total radon daughters, radon, barometric pressure, and relative humidity as functions of time, September 12, 1988 9 3. Total radon daughters, radon, barometric pressure, and relative humidity as functions of time, September 13, 1988 10 4. Total radon daughters, radon, barometric pressure, and relative humidity as functions of time, September 14, 1988 11 TABLES 1. Participants 3 2. Participant equipment and procedures 3 3. Radon daughter concentrations 6 4. Working level concentrations 7 5. Ratio of reported working levels over average working levels 8 6. Ratio of calculated working levels using reported radon daughter concentrations over reported working levels 8 7. Ratios of flow-corrected working levels over average working levels 12 UNIT OF MEASURE ABBREVIATIONS USED IN THIS REPORT cm/s centimeter per second MeV million electron volt ft foot min minute h hour mm millimeter hp horsepower fim micrometer kBq/m 3 kilobecquerel per cubic meter pCi/L picocurie per hter kPa kilopascal WL working level L/min hter per minute INTERNATIONAL INTERCALIBRATION AND INTERCOMPARISON PROGRAM RADON DAUGHTER MEASUREMENTS Exercise at the Twilight Mine, Uravan, CO By W. E. Cooper 1 and R. F. Holub 2 ABSTRACT The International Inter calibration and Intercomparison Program (HIP), consisting of several selected laboratories from four countries, held a radon progeny intercomparison measurement at the U.S. Bureau of Mines experimental Twilight Mine on September 12-14, 1988. Grab samples were taken at four different conditions of low and high radon progeny and condensation nuclei concentrations, respectively. The results showed good agreement among all seven participants. The coefficient of variation of all measurements was 4.7%; after minor corrections for flows and some systematic biases, it was reduced to 3.2%. fining engineer, U.S. Mine Safety and Health Administration, Department of Labor, Denver, CO. 2 Physicist, Denver Research Center, U.S. Bureau of Mines, Denver, CO. INTRODUCTION The accurate assessment of both occupational and gen- eral public exposure to radon and radon daughters is de- sirable to estimate their associated carcinogenic risk. For accurate exposure assessment, it is necessary to quantita- tively evaluate the accuracy of different methods and equipment used to measure radon and radon daughter concentrations. In 1983, the Committee on Radiation Protection and Public Health (CRPPH) of the Organiza- tion for Economic Cooperation and Development, Nuclear Energy Agency (OECD/NEA) recognized this necessity and decided to set up an international program of inter- calibration and intercomparison of equipment and tech- niques used for the monitoring of radon, thoron, and their short-lived daughters. From the beginning, this program was merged with a similar program conducted by the Commission of the European Communities (CEC). The primary purpose of the program was to quantitatively assess measurement differences among international lab- oratories or groups to provide a forum for alleviating or reducing differences and inaccuracies. Because of the importance of accurate radon measurements in mining health and safety, the U.S. Bureau of Mines was one of the participating organizations from the United States. The program was initially divided into three parts: intercalibration and intercomparison of radon measure- ments, intercalibration and intercomparison of radon daughter measurements (laboratory environment), and intercomparison of radon daughter measurements in real mine and dwelling conditions. The first two parts of the program have been completed and the results reported (7-2). 3 This report summarizes the results of one of sev- eral intercomparisons performed at mines and dwellings that will be included in the report on the third part of the program. ACKNOWLEDGMENTS The authors acknowledge the assistance of T. H. Davis, electronics technician, and R. F. Droullard, geophysicist, both of the Denver Research Center, in preparing the mine, in performing the continuous measurements, and in organizing this exercise. MEASUREMENT FACILITIES AND PROCEDURES Radon daughter grab sample measurements for this in- tercomparison were taken in the controlled mine atmo- sphere of the Bureau's Twilight Mine, located about 10 miles northwest of Uravan, CO. The mine is a previously operating uranium-vanadium mine, which was acquired by the Bureau to conduct in-house and contract research. The ore zone consists of a well-sorted, fine-grained, highly fractured sandstone with abundant carbonaceous material. A plan view map of the mine configuration and facilities is included as figure 1. The mine and its facilities are de- scribed in detail elsewhere (3). The measurements were done in the air-cleaning test area shown in figure 1. The ventilation system of the mine consists of twin 20- hp primary fans (back to back) located at the main exhaust portal (portal B) and a two-stage, 7-1/2-hp each, second- ary fan located at bulkhead B of the North Loop (fig. 1). The secondary fan automatically turns on in the event of power failure. The primary fan ran continuously through- out the intercomparison, while the secondary fan was used only as needed to provide recirculation around the North Loop, thereby increasing radon daughter concentrations in the measurement area. A small diesel engine was sit- uated at drift IL5 and used as required to entrain diesel pollutants into the mine air. Throughout the intercom- parison, continuous measurements of radon, radon daugh- ters, barometric pressure, and relative humidity were taken to evaluate factors that may affect radon daughter concen- trations. All of these measurements, except barometric pressure, were taken in the measurement area shown in figure 1. Barometric pressure was measured outside the mine near the instrument trailer. Details about the mon- itoring equipment are given in reference 3. The intercomparison participants and their equipment and procedures are listed in tables 1 and 2. Grab samples were taken under four conditions: 1. Low radon daughter concentration (0.22 to 0.50 WL) with no diesel pollutants; 2. Low radon daughter concentration (0.31 to 0.33 WL) with diesel pollutants; 3. High radon daughter concentration (0.86 to 0.94 WL) with no diesel pollutants; Italic numbers in parentheses refer to items in the list of references preceding the appendix. 4. High radon daughter concentration (0.73 to 0.92 WL) with diesel pollutants. The ranges of radon daughter concentrations presented are the ranges of the average concentration obtained by the participants. The participants' filter holders were posi- tioned near the middle of the mine airway with the filter faces directed toward the mine airflow. Mine air velocities (about 50 cm/s) in the measurement area were higher than the pump flow rate air velocities at the filter face. The filter holders were kept within a few centimeters of each other to help minimize effects due to measurement of different air. Table 1 .-Participants 1 Abbreviation Atomic Energy Control Board AECB Australian Radiation Laboratory ARL Environmental Measurements Laboratory, U.S. Department of Energy EML Department of Energy, Mines, and Resources, CANMET EMR Mine Safety and Health Administration, U.S. Department of Labor MSHA Bureau of Mines, U.S. Department of the Interior USBM University of Salzbu rg U.S. l See appendix for more detailed listing. Table 2.-Participant equipment and procedures Detector Counter efficiency Filter Pump flow rate, L/min Participant Type Manufacturer Type Diam, mm Pore size, /xm Method AECB . . . ZnS Trimet. NURAD . . . 0.435 .440 Mi Hi pore membrane AA. 25 0.8 3.70 3.80 5-min modified Tsivoglou. ARL ZnS drawer assembly. ARL .444 Gelman membrane GA-4. 25 .8 6.12 Do. EMI ZnS Th-29-B TD-19. ELM .470 Reeve angel glass fiber, 934AH. 50 NAp 3.20 Do. EMR . . . ZnS Trimet. NURAD . . . .467 Millipore membrane AA. 25 .8 3.63 Do. MSHA . . ZnS radon- flask detector. Ludlum . . . u .440 3 .476 4 .488 Gelman glass fiber A/E. Millipore membrane AA. 25 25 NAp .8 4.47 3.94 3.92 Do. USBM . . . . do. . . . . . do .477 . . do 25 .8 2.80 Do. U.S Silicon- diode. Pylon .20 Pylon 25 NAp 6.00 Alpha-spectroscopy (RaA-RaC). NAp Not applicable. 1 Hlter self-absorption included. 2 Sept. 12, 1988. 3 Sept. 13, 1988. 4 Sept. 14, 1988. NOTE.-Reference to specific products does not imply endorsement by the U.S. Bureau of Mines. IRI Power center IR2 Golf - cart charging system ILI Protective clothing orea IL2 Storage area I L3 Charging center Site IR3 IR5 IR5-I IR5-2 IR6 IR7 IR8 IL4 IL5 IL6 IL6-I IL6-2 IL7 IL8 IL9 ILIO 2RI 2R2 2R3 2R4 2R5 2R6 3RI 3R2 3R3 3R4 3LI 3L2 3L2-I 3L2-2 3L2-3 3L2-4 3L3 3L4 3L5 3L6 3L6-I 3L6-2 3L6-3 3L6-4 3L6-5 3L6-6 3L7 Width, ft 10 10 10 8 10 10 15 20 10 20 30 30 15 10 10 10 10 20 10 10 10 10 10 20 20 10 10 10 10 20 Length, ft 25 25 30 40 25 55 50 50 20 20 65 25 35 7 25 27 35 55 15 5 5 15 5 5 30 15 5 35 115 20 10 35 30 30 10 20 Instrument trailer 3] Office Figure 1.-Plan map of the Twilight Mine. North Loop is defined by bulkheads A and B. RESULTS AND DISCUSSION The results of the continuous measurements of radon, radon daughters, barometric pressure, and relative hu- midity are presented in figures 2-4. Also shown on these figures are the time periods for which the diesel engine was operating and the bulkhead B secondary fan (North Loop fan) was on. The relative humidity was high (60% to 70%) on September 12, 1988, because of rain occurring outside the mine. The continuous radon daughter con- centration measurements lag behind the radon concen- tration measurements about 1 h because of the detection methods utilized. As expected, the ratio of the radon daughter concentration over the radon concentration in- creased with the entrainment of diesel pollutants. These figures also show that barometric pressure inversely af- fected the radon concentration, as reported previously (4). The reported results of the individual radon daughter concentration measurements for three consecutive days are presented in table 3. Also included are the calculated average concentration and coefficient of variation for each sample time. These results showed average coefficients of variation of 13%, 10%, and 15%, respectively, for RaA, RaB, and RaC at low concentrations (0.22 to 0.50 WL). These low concentration results corresponded to average concentrations of 89, 33, and 22 pCi/L, respectively, for RaA, RaB, and RaC. At high concentrations (0.73 to 0.94 WL), September 14, the results corresponded to av- erage concentrations of 170, 91, and 64 pCi/L and coef- ficients of variation of 11%, 6.7%, and 8.2%, respectively, for RaA, RaB, and RaC. Lower coefficients of variation at the high concentrations were expected because of a reduction in the statistical counting uncertainty. The reported radon daughter concentrations are pre- sented in table 4. Also listed in the table are the average concentrations for each sample time and the coefficients of variation for the sampling results at each time. The coef- ficients of variation ranged from 11.4% to 2.1%, with an overall average coefficient of variation of 6.0%. The reported radon daughter sampling results for each of the participants was analyzed further by calculating the ratio of the reported working level concentration and the average concentration for each sample time. These cal- culated results, along with the average ratio and standard deviation for each participant, are listed in table 5. The average ratio provides an indication of the average percent that the participants' results were above or below the average concentration. The results showed an average ratio range of 0.957 to 1.046. The standard deviation provides an indication of the variability of the participants' sampling results. Some uncertainty in determining the actual working level would also be included in the listed standard deviations because the average concentration was used to estimate the actual working level. The av- erage standard deviation for the participants (the last column in table 5) was only 4.7%. This low standard deviation indicates that the measurement uncertainty for each of the participants was relatively constant. It also indicates that the differences in average ratio among the participants are probably largely due to systematic bias. The amount of systematic bias due to computational differences in converting individual radon daughter con- centrations to working levels was analyzed by converting all of the reported individual daughter concentrations to work- ing levels using a constant conversion factor and com- paring these results with the reported working level con- centrations. The ratio of the calculated working level and the reported working level was computed and the average ratio for each participant determined. The results of these calculations are presented in table 6. From the table 6 results, the Environmental Measure- ments Laboratory (EML) and the Mine Safety and Health Administration (MSHA) showed some systematic bias when converting individual radon daughter concentrations to working levels. These systematic biases were calculated at about 1% for EML and 2% for MSHA. The bias for MSHA resulted from using a conversion factor of 1.28E5 MeV = 1 WL instead of 1.3E5 MeV = 1 WL. For EML, the indicated bias is probably due to two factors: (1) the use of half- lives of 3.11 min and 19.9 min, respectively, for RaA and RaC instead of 3.05 min and 19.7 min, and (2) reporting the individual radon daughter concentrations to only two significant digits, while the other participants reported their results to three significant digits. The lower number of significant digits resulted in a higher standard deviation for the ratio than those obtained for the other participants. This higher standard deviation would result in a higher uncertainty for EML's average ratio. These estimated systematic biases should result in their measure- ments being above the average results by the appropriate percentages. It was noticed that the Department of Energy, Mines, and Resources (EMR), MSHA, and the Atomic Energy Control Board (AECB) used the same pump calibration device at the minesite and all three participants' results were above the average. This prompted a further analysis of their pump calibration device in the laboratory. The pump calibration device used was a Gilibrator, similar to the Buck Calibrator recently tested by MSHA (5). The Buck Calibrator showed a systematic bias of 1.4% at a flow rate of about 2.0 L/min (5). A laboratory compari- son of the Gilibrator against a Brooks flowmeter at 4.0 L/min showed a systematic bias of about 2.5%. This indicates that the results of the three participants are probably systematically biased about 2.5% high because of an inaccurate pump flow rate calibration at the time of the intercomparison. However, as was apparent during the last intercomparison in France, in June 1989, the problem of measuring flow has not been satisfactorily resolved. Table 3.-Radon daughter concentrations, picocuries per liter Date and participant Sept. 12, 1988: AECB ARL EML EMR MSHA USBM Average COV % . . Sept. 13, 1988: AECB ARL EML EMR MSHA USBM Average COV % . . AECB ARL EML EMR MSHA USBM Average COV % . . AECB ARL EML EMR MSHA USBM Average COV % . . See notes at end of table Time: 14:01 Time: 15:15 Time: 16:09 RaA RaB RaC RaA RaB RaC RaA RaB RaC 95.7 35.7 17.6 111.3 32.1 13.9 82.2 31.4 21.8 84.9 32.1 22.9 105.4 29.8 16.5 88.6 34.9 17.8 NA NA NA 89.1 30.2 17.0 81.0 31.6 22.1 NA NA NA NA NA NA NA NA NA 69.3 31.1 22.8 83.6 27.7 18.9 78.2 30.5 20.4 74.7 26.4 26.2 93.7 28.6 16.2 94.5 34.3 14.8 81.15 14.4 31.33 12.2 22.38 15.9 96.61 29.70 11.9 5.7 16.51 10.8 84.90 7.8 32.54 6.0 19.39 15.9 Time: 9:00 Time: 10:00 Time: 11:00 RaA RaB RaC RaA RaB RaC RaA RaB RaC NA 60.1 NA 61.7 79.9 NA 77.6 72.0 56.7 103.7 88.4 69.7 78.2 20.9 RaA 143.0 148.0 121.5 169.6 157.1 137.9 146.18 11.3 NA 18.6 NA 22.5 22.6 NA NA 16.2 NA 15.8 17.3 NA 51.6 62.3 62.1 57.2 46.8 60.3 19.2 22.3 20.0 24.8 18.7 17.9 20.0 13.0 13.0 15.6 22.3 12.6 68.4 84.9 72.9 99.3 79.9 70.8 32.0 38.7 37.8 40.3 40.9 34.5 36.2 25.5 27.5 38.3 37.2 29.8 21.1 19.4 28.4 21.2 24.2 23.6 96.5 28.1 86.7 30.1 72.9 29.4 116.2 30.0 78.5 21.5 81.3 32.8 20.5 17.8 17.8 18.8 26.5 16.1 112.9 121.0 108.0 102.4 108.9 124.0 40.4 35.6 38.6 43.9 37.6 37.0 32.42 16.9 22.97 13.8 88.68 17.7 28.66 13.3 19.59 18.8 112.87 7.3 37.36 5.4 Time: 15:00 Time: 16:00 RaB RaC RaA RaB RaC 52.4 45.4 43.2 54.5 50.6 45.7 26.8 28.5 27.0 25.2 31.8 33.2 112.9 114.0 116.1 144.8 107.2 124.6 41.7 39.1 45.9 51.8 42.7 43.7 29.7 28.8 21.6 26.8 31.8 29.8 48.64 9.3 28.76 10.8 119.94 11.2 44.15 9.9 28.08 12.7 31.3 24.9 24.3 22.4 31.4 26.4 67.23 16.4 21.23 10.7 16.43 4.7 56.71 20.48 11.1 12.7 16.08 25.7 79.37 14.5 37.37 9.2 26.79 14.1 Time: 12:00 Time: 13:00 Time: 14:00 RaA RaB RaC RaA RaB RaC RaA RaB RaC 23.6 21.4 18.4 27.7 27.4 20.5 23.16 16.4 Table 3.-Radon daughter concentrations, plcocurles per liter-Continued Date and participant Sept. 14, 1988: AECB ARL EML EMR MSHA USBM Average COV % . . AECB ARL EML EMR MSHA USBM Average COV % . . AECB ARL EML EMR MSHA USBM Average COV % . . COV Coefficient of variation. NA Not available. Time: 9:00 Time: 10:00 Time: 11:00 RaA RaB RaC RaA RaB RaC RaA RaB RaC 153.2 155.0 126.9 155.5 136.3 116.2 184.1 153.0 170.1 156.5 181.3 169.1 169.02 7.5 RaA 201.7 NA 180.9 238.5 226.8 197.2 209.02 11.1 89.0 82.1 72.9 81.5 77.4 68.2 61.5 54.5 54.0 51.7 54.9 51.6 183.1 159.0 132.3 144.4 171.0 147.9 97.0 89.5 81.0 86.0 89.1 84.8 62.0 56.6 62.1 62.6 64.3 66.2 177.5 169.0 129.6 172.4 179.5 158.2 100.1 96.5 83.7 94.3 91.5 88.7 111.2 96.3 91.8 96.1 90.7 99.8 70.5 68.9 62.1 67.5 70.9 68.5 182.7 159.0 170.1 198.8 199.6 172.6 104.8 97.6 91.8 98.6 93.3 92.8 73.5 68.1 59.4 64.4 73.5 72.1 146.1 NA 191.7 189.3 171.8 149.8 97.66 7.6 68.07 4.7 180.47 9.1 96.48 5.1 68.50 8.3 169.74 12.6 Time: 14.59 RaB RaC 103.6 NA 91.8 103.7 90.8 93.3 63.2 NA 56.7 56.1 64.3 65.6 96.63 6.7 61.19 7.3 88.9 NA 94.5 93.3 85.9 83.6 89.23 5.2 69.0 59.9 70.2 62.5 71.3 72.3 140.52 11.9 78.52 9.4 54.70 6.6 156.28 87.90 11.9 6.2 62.30 5.2 164.37 11.3 92.47 6.3 67.53 7.5 Time: 12:00 Time: 13:00 Time: 14:01 RaA RaB RaC RaA RaB RaC RaA RaB RaC 81.7 NA 51.3 55.9 76.4 66.4 66.35 19.6 Table 4. -Working level concentrations Participant Sept. 12, 1988 Sept. 13, 1988 14:00 15:15 16:09 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 AECB 0.345 0.329 0.325 NA 0.225 0.350 0.341 0.318 0.409 0.513 0.438 ARL . .337 .323 .336 0.218 .227 .378 .277 .310 .388 .492 .425 EML. NA .313 .329 NA .215 .357 .307 .295 .380 .454 .442 EMR NA NA NA .238 .244 .392 .382 .344 .388 .548 .515 MSHA .325 .308 .317 .265 .230 .414 .376 .293 .412 .546 .453 USBM .309 .304 .329 NA .202 .346 .311 .310 .392 .497 .461 U.S. . , fle . NA NA NA NA NA .361 .329 .290 .355 .482 .449 Avera .329 .315 .327 .240 .224 .371 .332 .309 .389 .505 .455 SD . .016 .010 .007 .024 .014 .025 .038 .019 .019 .034 .029 COV . % . . 4.8 3.3 2.1 9.8 6.4 6.7 11.4 6.1 4.9 6.7 6.4 Sept . 14, 1988 9:00 10:00 11:00 12:00 13:00 14:01 14:59 AECB 0.838 0.911 0.947 1.016 0.993 0.906 0.968 ARL . .781 .832 .890 .905 .915 .856 .875 EML . .721 .780 .831 .887 .879 .864 .879 EMR .769 .821 .892 .904 .949 .881 .987 MSHA .750 .882 .930 .927 1.969 .913 .950 USBM .658 .829 .882 .936 .917 .825 .920 U.S. . , .634 .832 .861 .897 1.025 NA NA Average . .736 .841 .890 .925 .950 .874 .930 SD . , .071 .043 .039 .044 .050 .033 .047 COV . % . . 9.7 5.1 4.4 4.7 5.3 3.8 5.0 COV Coefficient of variation NA Not available. SD Standard deviation. Table 5.-Ratio of reported working levels over average working levels Participant Sept. 12, 1988 Sept. 13, 1988 14:01 15:15 16:09 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 AECB 1.049 1.043 0.993 NA 1.005 0.943 1.028 1.031 1.051 1.017 0.963 ARL 1.024 1.024 1.027 0.907 1.014 1.018 .835 1.005 .997 .975 .935 EML NA .992 1.006 NA .961 .962 .925 .956 .977 .900 .972 EMR NA NA NA .990 1.090 1.056 1.151 1.115 .997 1.086 1.133 MSHA .988 .977 .969 1.103 1.028 1.115 1.133 .950 1.059 1.082 .996 USBM .939 .964 1.006 NA .902 .932 .937 1.005 1.007 .985 1.014 U.S NA NA NA NA NA .973 .991 .940 .912 .955 .987 SD .048 .033 .021 .098 .064 .067 .114 .061 .049 .067 .064 Sept . 14, 1988 Av ratio SD 9:00 10:00 11:00 12:00 13:00 14:01 14:59 AECB 1.139 1.083 1.064 1.099 1.046 1.036 1.041 1.037 0.047 ARL 1.061 .989 1.000 .979 .964 .979 .941 .982 .053 EML .980 .927 .933 .959 .926 .988 .945 .957 .029 EMR 1.045 .976 1.002 .978 .999 1.008 1.061 1.046 .058 MSHA 1.019 1.049 1.044 1.003 1.020 1.044 1.022 1.033 .051 USBM .894 .986 .991 1.012 .966 .944 .989 .969 .038 U.S .862 .989 .967 .970 1.079 NA NA .966 .054 SD .097 .051 .044 .047 .053 .038 .050 NAp NAp NA Not available. NAp Not applicable. SD Standard deviation. Table 6.-Ratio of calculated working levels using reported radon daughter concentrations over reported working levels Partici pant Sept. 12, 1988 Sept. 13, 1988 14:01 15:15 16:09 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 AECB . . . 1.001 1.002 1.001 NA 1.001 1.000 1.003 1.002 1.001 1.001 1.001 ARL .996 .995 .996 .994 .995 .997 .996 .995 .993 .994 .996 EML NA .986 .992 NA .994 1.002 .990 .986 .989 .980 .980 EMR . . . NA NA NA .994 .996 .996 .995 .994 .995 .995 .994 MSHA . . .967 .965 .982 .987 .984 .983 .984 .986 .984 .984 .984 USBM . . .999 .994 .993 NA .990 1.002 1.000 1.001 1.000 1.002 1.001 Sept . 14, 1988 Av ratio SD 9:00 10:00 11:00 12:00 13:00 14:01 14:59 AECB . . . 1.001 1.001 1.001 1.001 1.001 1.001 1.001 1.001 0.001 ARL .998 .997 .997 .998 .998 NA NA .996 .002 EMI .974 .999 .987 .984 .982 1.005 .983 .988 .008 EMR . . . .997 .997 .997 .997 .996 .996 .994 .996 .001 MSHA . . .984 .984 .984 .983 .984 .984 .984 .982 .006 USBM . . 1.001 1.001 1.001 1.000 1.001 1.002 1.002 .999 .004 NA Not available. SD Standard deviation. NOTE. -WL = (RaAx 0.0010287) + (RaB x 0.00507745) + (RaCx 0.0037323), where RaA, RaB, ; and RaC are concentrations in picocuries per liter. 5 rr o o u rr LJ h- X < O Q < 1.3 1.2 1.1 1.0 .8 .6 .2^ KEY — Radon daughters — Radon-222 — Barometric pressure — Relative humidity J i L I . I 1.0 5.5 5.0 4.5 cr CD 4.0 2 o r- < 3.5 * -3.0 i±j CJ ■z. o U CO 2 5 °° i ■z. o 2.0 § or 100 90 > 1- 80 Q S Z> X 70 LJ > h- 60 < _l III rr 50 40 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 — — ,*•»••»* — ^ *»»» ,1,1,1,1,1,1 -^Diesel engine — •- running .III! 1,1,1,- 85.4 o o. 85.2 lj £T Z> CO CO LJ 85.0 £ CJ rr 84.8 w o rr < -84.6 8 10 12 14 16 18 20 22 24 TIME OF DAY Figure 2.-Total radon daughters, radon, barometric pressure, and relative humidity as functions of time, September 12, 1988. 10 o h- < rr h- -z. UJ o -z. o u rr UJ r- X o < O Q < rr 1.3 1.2 1.1 1.0 - .9 - .8 .7 .6 .3 .2 100 i — 1 5.5 KEY Radon daughters Radon- 222 Barometric pressure Relative humidity s — ^ -~'^~s J i L J i L 85 90 >-" l- 80 o ^ Z> X 70 UJ > 1- 60 < _l III rr 50 40 1 1 1 1 1 1 1 1 I 1 1 1 1 1 1 1 1 1 1 1 1 1 ' . — v -O'* ■ -"' ** \ _• ..-=. — \S 1 1 , 1 . 1 . 1 . 1 1 1 1 1 . 1 . — North Loop fan on—* I.I.I. - 2 4 6 8 10 12 14 16 18 20 22 24 1.0 85.4 o a_ J* 85.2 £ => CO CO UJ 85.0 8: o rr -^84.8 -84.6 UJ o rr < m TIME OF DAY Figure 3.-Total radon daughters, radon, barometric pressure, and relative humidity as functions of time, September 13, 1988. 11 1.3 1.2 _J 1 1 s z. o 1.0 h- < rr .9 \- z UJ 8 o z O o .( QL Id r- .6 X o < .5 O Z /\ o o < rr .5 .2- r^ r i — ' — i — r ~T KEY Radon daughters Radon-222 Barometric pressure Relative humidity 100 90 >- h- 80 Q 2 Z> X 70 LlI > h- 60 < _l UJ rr 50 40 5.5 5.0 -4.5 -4.0 -3.5 3.0 2.5 2.0 1.5 J i 1 1.0 m < r- z UJ u z o o C\J (\J CO I z o Q < rr North Loop fan on- *Diesel engine* running -K A. o 8 10 12 14 TIME OF DAY 18 20 22 24 85.4 o Q_ 85.2 £ CO CO UJ 85.0 ai y rr UJ 84.8 o rr < GO 84.6 Figure 4.-Total radon daughters, radon, barometric pressure, and relative humidity as functions of time, September 1 4, 1 988. 12 The pump flow rates for the affected three participants were adjusted for the probable systematic bias due to pump miscalibration (2.5%), and the results are presented in table 7. The pump flow rate corrections indicate that the maximum average percentage that a participant's results were above or below the average concentration was only 3.2%. These results appear quite good considering these were field measurements and some difference would be expected because of measurement of different air and statistical counting uncertainties in the methods. Table 7.-Ratios of flow-corrected working levels over average working levels Participant Sept. 12, 1988 Sept. 13, 1988 14:01 15:15 16:09 9:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 AECB ARL EML EMR MSHA USBM U.S SD AECB ARL EML EMR MSHA USBM U.S SD NA Not available. NAp Not applicable. SD Standard deviation. 1.036 1.037 NA NA .976 .951 NA .043 9:00 1.123 1.073 .991 1.031 1.005 .904 .871 .089 1.028 1.034 1.002 NA .962 .974 NA .032 10:00 1.068 1.000 .938 .963 1.034 .997 1.000 .043 0.978 1.037 1.015 NA .954 1.015 NA .033 NA .923 NA .983 1.094 NA NA .087 0.993 1.027 .973 1.077 1.015 .914 NA .055 0.930 1.030 .973 1.042 1.100 .943 .983 .060 1.014 .845 .936 1.136 1.118 1.003 .103 1.016 1.016 .967 1.099 .936 1.016 .950 .055 1.036 1.008 .987 .983 1.044 1.018 .922 .041 Sept. 14, 1988 11:00 12:00 13:00 14:01 14:59 Av ratio SD 1.049 1.011 .944 .988 1.030 1.001 .978 .035 1.084 .990 .970 .964 .989 1.023 .981 .042 1.032 .974 .937 .985 1.006 .977 1.091 .050 1.024 .992 1.001 .996 1.032 .956 NA .027 1.029 .953 .958 1.049 1.009 1.002 NA .038 1.023 .993 .968 1.032 1.020 .980 .977 NAp 0.046 .053 .029 .057 .051 .038 .055 NAp 1.003 .986 .910 1.071 1.067 .996 .966 .056 0.950 .945 .983 1.117 .982 1.025 .998 .058 CONCLUSIONS The maximum average percentage that a participant's results were above or below the average concentration for each sample time was only 4.7%. After pump flow rate correction for three of the participants, which was nec- essary because of an inaccurate pump calibration device, this maximum reduced to 3.2%. Systematic biases of about 1% and 2%, respectively, in two of the participants' results were due to differences in converting individual daughter concentrations to working levels. The results of the intercomparison appeared to be reasonably good when consideration is given to the statistical counting uncer- tainties involved and the possibility that the participants measured different air. The intercomparison was beneficial in identifying mea- surement errors due to inaccurate pump calibration and different procedures for converting daughter concentra- tions to working levels. Additional intercomparisons should be periodically performed to assist laboratories in identifying measurement errors and helping to assure accurate exposure assessments. REFERENCES 1. Knutson, E. O. (ed.). International Intercalibration and Intercomparison of Radon, Thoron and Daughters Measuring Equipment-Report on Part 1, Radon Measurement. Nucl. Energy Agency of Organ, for Econ. Coop, and Dev., and Comm. of Eur. Communities, 1986, 62 pp. 2. Solomon, S. B. (ed.). International Intercalibration and Intercomparison of Radon, Thoron and Daughters Measuring Equipment-Report on Part II, Radon-Daughter Measurement. Nucl. Energy Agency of Organ, for Econ. Coop, and Dev., and Comm. of Eur. Communities, 1988, 80 pp. 3. Droullard, R F., T. H. Davis, E. E. Smith, and R. F. Holub. Radiation Hazard Test Facilities at the Denver Research Center. BuMines IC 8965, 1984, 22 pp. 4. Holub, R. F., and P. J. Dallimore. Factors Affecting Radon Transport and the Concentration of Radon in Mines. Paper in Proceedings of International Conference on Radiation Hazards in Mining, ed. by E. Geomez. Soc. Mn. Eng. AIME, 1982, pp. 1022-1028. 5. Gero, A. J. Evaluation of Four Fast-Response Flow Measurement Devices. U.S. Dep. Labor IR 1163, 1988, 8 pp. 13 APPENDIX.-PARTICIPANTS Australia: United States: Australian Radiation Laboratory Dr. Stephen Solomon Lower Plenty Road Yallambie, Victoria Australia Bureau of Mines U.S. Department of the Interior Dr. Robert F. Holub Mr. Ted H. Davis Denver Research Center Building 20, Denver Federal Center Denver, CO 80225 U.SA Canada: Atomic Energy Control Board Ms. Georgena MacDonald P.O. Box 1046 Ottawa, Ontario Canada, KIP 5S9 Environmental Measurements Laboratory U.S. Department of Energy Dr. Earl O. Knutson Dr. Keng Wu Tu 376 Hudson Street New York, NY 10014 U.SA. Department of Energy, Mines, and Resources CANMET Dr. Jaime Bigu P.O. Box 100 Elliott Lake, Ontario Canada, P5A 2J6 Mine Safety and Health Administration U.S. Department of Labor Mr. Wade E. Cooper, P.E. P.O. Box 25367 Denver Federal Center Denver, CO 80225 U.SA. Europe: University of Salzburg Dr. Friedrich Steinhausler Division of Biophysics Hellbrunnerstr. 34 A-5020 Salzburg Austria INT.BU.OF MINES,PGH.,PA 29169 TJ m 81 © DO C 5 z w _^ r- 4 O ■n ■n 7 5-m o so O > l treel :on, ?3 ■o i- D- 5 » 3 1 8 0) b. z ■& c/> i c/> 3 ^ to (B V 00 ■■ i o 5' o •I > z m D c > i- o -o "0 O 3D -I C z m O -< m 33 447-90 O A* . ^** .\fife\ V./ ^V/*. v.** /*ato\ *<&> _<& /aV^. ^ ^ v^ai ,^ ^ >' ^-*5^>* v V ;f -* ; V 'V-SffPV 3 ' X-.>*\ *y?S**\* ***'^% % \^ \> * iJs&fr.V Jti&k? * X-^fcrX y..5dfc.V >^^V>V;£fr*% -A, &**£&.+*» >*.*5^V *\c^% ^..i5K -4^ 4<* ^n 4&'-^ wjc^ . ** -^ \a s>" <&'% v* ~* . . . .*<*> >*V^*>c ^^ l~ .r * 4> ^ « ^ '" A A Vv ^ • a v ^ - P++ 5°* i* * «••• >b, »o.T« A • A^^ ' » . • «5°* r oV & tu •, aV«^. a* ..'»•. % <& %, v HECKMAN BINDERY INC. NOV 90 «jg«- N. MANCHESTER, ^^^^ INDIANA 46962 0° *»-,> * £ % 'SB/PS J* % L H°xv . ' • . '^ .« V B o - • . * «o«». ^ * * °* .4> .o"". *