ML19210E993
| ML19210E993 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 11/21/1979 |
| From: | Branagan E, Congel F, Pasciak W Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19210E923 | List: |
| References | |
| NUDOCS 7912130363 | |
| Download: ML19210E993 (23) | |
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{{#Wiki_filter:.. h / 5 ENCLOSURE 3 J A METHOD FOR CALCULATING DOSES TO THE POPULATICS FROM 233Xe RELEASES DURING THE THREE ? MILE ISLAND ACCIDENT h Walt Pasciak, Edward F. Branagan, Jr., Frank J. Congel, and James E. Fairobent U.S. Nuclear Regulatory Commissior, Washington, D.C. 20555 ABSTRACT On March 28, 1979, a series of events occurred at Three Mile Island, Unit 2, which resulted in a significant release of primary circulating system cooling water onto the containment building floor. Some of this water reached the auxiliary building floor via pathways that are not yet known. Th xenon activity in the water entered the atmosphere of the auxiliary building and over a period of a few days passed through the building air filters to the atmosphere. The resulting offsite radiation levels were much greater than dering routine operation. Doses rect ec by the population were mainly due to 123Xe. The health an'd safety
- "celeences of these releases were analyzed and found to be minimal in an ad hM eragency report published by NRC, HEW, ard EPA in May 1979.
In that rert. , the dose to the general population is estimated by two different methods, t_.h of which rely on offsite TLD measuremer.tz. This article describes r in detaii one of the calculational methods that was used in the report. Tais method utilizes the topological tice averaged meteorological dispersion factors derived fro: meteorological data obtained during ths accident as well as TLD data from the site environs. 1546 238 2NY,, Toisino %S \\
Thedosetoth'popukationresidingwithin50milesoftheaccidentwasestimated e to be about 2600 person rems by this method. a e 9 1546 239 \\ 6 -{ 2-
/ INTRODUCTION In the ad hoc interagency. report (Ad79) by NRC, HEW and EPA, the health and safety consequences of the atmospheric releases made as a result of the first ten days of the accident at.Three Mile Island (TMI) were evaluated and found to be minimal. Most of the dose received by the population was a result of 188Xe emissions. In the report, several estimates of the' dose from these emissions were made. Most of the estimates were based on a method which interpolated data from thermoluminescent dosimeters (TLD) located at numerous \\ locations around the site. This was done by dividing the area around the site into 16 equal compass sectors with their center located between the two reactors. Each sector was divided into sections delimited by distances from the center s of 0.5, 1.0, 2.0, 3.0, 4.0, 5.0, 10.0, 20.0, 30.0, and 50.0 miles. For each sector in which two TLD's were located, a straight line was drawn throu'gh the two data points on log-log paper. This line was used to estimate the dose in the sector out to the furthest dosimeter. Similar interpolations were adopted, for sectors with only one or no TLD's by utilizing data in adjacent or nearby sectors. For distances beyond the farthest data points, the dose was ass,umed to decaease as distance to the 1.5 power. In this manner, the dose was estimated for all individuals residing in a 50-mile radius of the site. Several approaches based on c'ifferent combinations of the TLD data were taken with this method to estimate the dose to the general population. r Another metnod was used in the report to verify the overall results of the interpolative method. This alternative method employed the use of calculated meteorological dispersion factors which were based on meteorological data 1546 240 / collected over thi cdurse of the releases, as well as on the TLD readings. The purpose of this paper is to describe this method and the results obtain'ed. e 1546 241 e / J BACKGROUND In reactor licensing, NRC estimates doses (H) to an individual from noble gas ~ releases in the following manner. It is assumed that an individual is immersed in a semi-infinite cloud of the noble gas (e.g., issXe). The dose to the individual immersed in the semi-infinite cloud is determined by taking the product of the concentration of the 133Xe in the cloud (X7 and a dose factor (DF) integrated over the time the individual is exposed to ti e cloud (at). The dose factor incorporates the absorption of radioactive decay particles and photons in air, the absorption and scattering of them as they pass through the body, and translates the energy deposited as a result of the absorption or scattering by the body into dose to each organ. Since X is the only variable that is time dependent under the integrand, the dose can be expressed'in terms of the time averaged value of the concentration (i) as is done in Equation (1). H= At DF (1) ~ USNRC Regulatory Guide 1.109 (Nu77a) describes the calculational method f'cr releases containing a spectrum of radioactive isotopes. Basically, a suTeation over all radionuclides is involved. The equations that follow are for a single nuclide release, but they can be easily generalized to a release spectrum. To more readily incorporate the results of meteorological dispersion models, the right side of Equation (1) is usually multiplied and divided by the time averaged rate of nuclide release source term (Q'), resulting in Ecuation (2). 1546 242 / j. H=.(i/Q')atDFQ' (2) Note that x/Q' is a purely meteorological parameter, independent of the magnitude oFthe source term. The output of meteorological dispersion models is in the form of time and space dependent x/Q' values. These models are described in Slade (S168) and the use of site specific data in them is described in Gifford (GiS1). To use this information in Equation (2), the time Nerage values, x/Q', are computed from the meteorological model results. These time averages are not expected to be exactly equal to the quotient of the time averages of X and Q' appearing in Equation (2) from the mathematical standpoint alone. In i practice, however, they are expected to be close because the time fLnctional form of X in the downwind sector is expected to closely resemble that of Q' provided the time rate of change of the release rate is not too great in comparison to the transit time from the emission point to the reception point. In consideration of the mechanism by which xenon passed from the water of the 6 auxiliary building to the atmosphere outside the building, it is expected that the releases were varying fairly slowly, and thus, (5/Q') = (X/Q'). The most reliable estimates of H are obtained when estimates of x/Q' are based upon meteorolog; cal variables measured at the site during the releases, and when Q' is cc-n. red simultaneously at the effluent sourcs. The time averaged values of these two parameters are then usJd in Equation (2), along with the dose factor from Regulatory Guide 1.109, to calculate doses. In routine licensing of nuclear power plants, NRC estimates doses by using annually averaged X/Q' values as described in USNRC Regulatory Guide 1.111 (Nu77b). 1546 243 l - The source terms for the average annual release are estimated by models d ~ ,1 in USNRC reports (Nu76) for pressurized water reactors and (Ca79) for boiling The method described below is different from that used in water reactors. typical NRC licensing case because it does not rely on direct ceaiurement o Instead, it relies on TLD field measurements of estimahesofthesourceterm. dose, and as discussed earlier, on meteorology measurements made over the course of the releases. 1546 244 N.
/ ~,' ~ CALCULATIONAL ljETHODS AND RESULTS Since TLDs were located only in 20 or so locations around the plant, it was necessary to use this information to characterize the system in a way that wou18 allow calculation of doses in all 160 sector sections. This was done by use of the ratio, K, which is equal to the dosimeter reading (background subtracted out) divided by the 5/Q' value at each dosimeter location, which has the same value, at least in theory, at each TLD location. The basis for expecting K to be the same in all sector sections can be shown mathematically as follows. The only terms of Equation (2) which are spatially dependent are H and i/Q', thus, the equation can be arranged so that all the spatial dependence is on one side as follows: \\ (3) H =atDF6, (X/Q') Since, for any given release period, AT, the three terms on the right of a Equation (3) are independent of space and time, hence, H/(i/Q') can be equated to a constant: (4) =K (X/Q') The' X value of Equation (4) is comp.ted for tua release periods during the The first period was 28 hours long (3/28; 4 a.m. to 3/29;# 8 a.m.) accident. These and the second period was 44 hours long (3/29; 8 a.m. to 3/31; 4 a.m.). time periods correspond to the durations the TLDs were exposed in the field. 1546 245 7 , /. v F>igure (1) depi' cts the locations of TLDs in the field. The TLDs at these 20 ~ locations were placed by Metropolitan Edison Company and are described in detail in the Ad Hoc Interagency Report (Ad79). Table (1) lists the dose from these TLDs (background subtracted out) for the two time periods. Thei/Q' va5es at each TLD location and for each time period for use in determining K r values were based on actual meteorological data, as mentioned above. Hourly calculations were made of the X/Q' value throughout each df the two periods. To determine the average value for each period at the 160 sector locations, the sum of the value at the location in question and the values of its two adjacent locations in the azimuthal direction, summed over each hour was taken and divided by the total number of hours. This summation results in a conservative estimate of i/Q', by as much as a factor of 3, as more contribution than actually occurs is figured in for the adjacent sector locations.\\ Tables (2) and (3) list the i/Q' values for the 160 sector sections for the first and second time period, respectively. The i/Q' values at each TLD location were obtained by interpolation of the data in Tables (2) and (3) and are listed in Table (1) for both time periods. Using H and i/Q' values obtained in this manner, values of K were determined by Ecuation (4) and are listed in the fourth and seventh columns of Table (1). The average K value for the first time period is 48.7 x 103 3 R-m /sec and for the second time period is 3.42 x 103 3 R-m /sec. Using the t-distribution from small sampling statistical theory, at the 95% comfidence level the value of K for the first time period is expected to be below 94.9 x 103 3 R m /sec and for the second time period is expected to be below 5.47 x 103 3 R-m /sec. It is apprcpriate that the upper limit of K is quantified here because, as shown 1546 246
/ below, both the individual dose and t,he population dose, as well as the estimated activity released, are proportional to the estimate of i(. The:K values of locations far from the plant should not be co sidered as rel_5able as those close in., Figure (1) shows that 5 stations (Stations 4G1, The K values 7F1, 7G1, SG1, and 15Gl) are nine miles or more from the plant. for these five stations are not considered as reliable as 4 hose for the other First, the uncertainty in the 5/6' increases with stations for three reasons. distance from the plant since site meteorological ceasurements are less likely i to represent local conditions. Second, the dose recorded by a TLD decreases as distance from the plant increases; hence, natural variations due to background, and other measurement uncertainties, have a greater effect. Third,since5/h' decreases as distance from the plant increases, and it appears in the\\ enominator d of Equation (4), equivalent absolute errors in i/Q' have a larger effect on far out stations than for close in stations. On this basis, these five stations are excluded from the data for the purpose of the dose and source term calculations presented below. With these exclusions, 5 for the first period becomes 8 R-m /sec anc for the second time period it becomes 2.15 x 103,R-m /sec. 3 14.1 x 103 Applying the t-distribr_ ion here as was don 2 aoove, at the 95% confidence level 3 R-m /sec the value of R for toe first time period is.exeected to be below 18.8 x 103 3 and its value for the second time period is exoected to be below 2.65 x 103 R-m /sec Table (4) lists the ccse for the inner boundary of the central 56 septor sections (out to five miles) for both time periods calculated with the expression H=R(i/6'). The R values used are those determined above after exclusion of the data from the 5 stations furthest out and the i/Q' values are from Tables 1546 247 - 10 _
/ ~ (2) and (3). Figu'res (2) and (3) depict these data drawn as isopleths on maps ~ - of the site vicinity for the first and second time period respectively. As Figure (2) indicates, general meteorological conditions were favorable for minimizing the individual dose which occurred during the first period as the releasi.d activity was blown.out over the river and dispersed significantly = before it reached inhabited areas. It should be remembered that the doses t presented in Table (4) and in Figures (2) and (3) represent an estimate of the dose that would be received by an individual if the individual was outdoors during the entire course of the passage of the noble gas cloud. In actual fact, it is known that a significant portion of the population residing near the plant avoided going outdoors or left the area completely. N The total dose received by the population residing within 50 miles of the piant was determined by multiplying the number of people living in each sector section by the dose for that section and summing this over all 160 sector sections. Doses were based on the projected 1930 population. The population data was obtained from the Ad Hoc Interagency Report (Ad79), and the dose datt was determined as was done with Table (4). For each sector se:-t en, the dose for the inner boundary was used; ter,ce, this method overestianet the actual cose since the cose within a sec;;r :..: tion is always higner. ..no inner boundary. For the first time periv;. the dose was calculated ;c t e 1900 person-rem and for the second time ;. iod it was 790 person-r::... x 1546 248 j ~ REFERENCES Ad79 Ad Hoc Interagency Dose Assessment Group, May 1979, ' Population Dose and Health Impact of the Accident at the Three Mile Island ~ Nuclear Station," Report NUREG-0558, U.S. Nuclear Regulatory Commission, Washington, D.C. Ca79 Cardile, F.P. and R.R. Bellamy (Editors), January 1979, " Calculation of Releases of Radioactive Materials in Gaseous and Liquid Effluents from Boiling Water Reactors," Report NUREG-0016, U.S. Nuclear Regulatory Commission, Washington, D.C. \\. Gi61 Gifford, F. A., Jr.,1961, "Use of Routine Meteorological Observations for Estimating Atmospheric Dispersion," Nucl. Safety 2, 47. Nu76 U.S. Nuclear Regulatory Commission, April 1976, " Calculation of Releases of Radioactive Materials in Gaseous and Liquid Effluents from Pressurized Water Reacto-s," Report NUREG-0017, Office of ' - Starda-ds Development, Washirgton, D.C. Nu77a U.S. Nuclear Regulatory Commission, October 1977, " Calculation of Annual Loses to Man from Routine Releases of Reactor Effluents for the Purpose of Evaluating Ccmpliance with 10 CFR Part 50,'kppendix I," Regulatory Guide 1.109, Rev. 1, Office of Standards Development, Washington, D.C. 1546 249
/' Hu77b U.S. Nucle &r Regulatory Comission, July 1977, " Methods for Estimating Atmospheric Transport and Dispersion of Gaseous Effluents in Routine Releases from Light Water Cooled Reactors," Regulatory Guide 1.111, Rev.1, Office of Standards Development, Washington, D)C. S168 Slade, D. H., (Ed.),1968, " Meteorology and Atomic Energy," Report TID-24190, U.S. Department of Commerce, Springfield, VA. 1546 250 s 4
/~ Table 1. Proportionality constant "K" derived from dosimetry and meteorological -data for two release times. First time period Second time period Station 3/28 (4 a.m.) to 3/29 (8 a.m.) 3/29 (8 a.m.) to 3/31 (4 a.m.) Meteorological Meteorological Dose,* dispersion,** Kt Dose,* dispersion,** Kt 3 mR sec/m3 103R-m /sec mR sec/m3 103R-m /sec 3 152 83.0 3.0E-5' 2.8 19.7 2.0E-5 0.98 1C1 7.8 8.6E-7 9.1 2.9 1 2'E-6 2.4 v 252 31.5 2.5E-6 13, 32.2 ,1.7E-5 1.9 452 21.1 1.6E-6 13. 124. 2.9E-5 4.3 4A1 6.4 3.0E-7 21. 34.0 1.6E-5 2.1 4G1 1.3 4.5E-9 290. 0.9 1.7E-7 5.3 552 17.6 3.0E-6 5.9 49.0 4.6E-5 1.1 sal 4.7 6.0E-7 7.8 8.0 1.7E-5 0.47 7F1 4.4 0. 7.5 1.7E-5
- 0. 44 7G1 4.2 0.;,c, g 7 7.1 1.7E-5
. 0.42 1.5 8C1 1he _ 3.4Hr-16. 0.7 2.9E-7 \\ 2.4 ii o 7.cE-6 952 . 4 -9' W 50&- 3.5'o 0.7 1.7E-7 4.1 9G1 4.5 9.0E-9 500. 10.5 1.9E-6 5.5 10E1 24.8 1.1E-6 23. 25.0 3.6E-5 1.6 1021 28.8 1.1E-6 26. 1.0
- 2. 4 E-7 4.2 1151 201.0 2.0E-5 10.
14.8 6.5E-6
- 2. 3 1231 5.f 2.6E-6 2.2 107.0 1.2E-4 O_.89 1452 liF.~
3.0E-5 3.5 9.2 3.6E-6
- 2. 6 1452
':K 3.0E-5 4.5 48.7 4.0E-5 1.2 15G1 3.0 7.0E-6 0.43 1.6 6.0E-8 27. 1651 . ;2 0. 6 4.0E-5 26. 83.3 4.8E-5 1.7 16Al 2 il. 2.0E-5 22. 45.0 1.9E-5 2.4 16Al C 5 5. 2.0E-5 ,5-id 5 .x Doses are casev en TLD readings for the indicated station. Doses have been corrects t for ba-i: ground radiation. Meteorological dispersion valves (i.e., X/Q') are based on real time meteorological averaged over the indicated time period. The reteorological data was obtained by The proportionality constant "K" is obtained by dividing the dose at a particular st T the appropriate time period by the corresponding meteorological dispersion factor (i ~ ~ 1546 251 Fdd -
Table 2. Average dowmtind meteorological dispersion values (R7({r) for different locations for a first time period (Mar. 20 (4. a.m.) to Mar. 29 (8 a.m.)), sec/m Downwind Distance, miles direction 0.5 1.0 2.0 5.0 4.0 5.0 10.0 20.0 30.0 50.0 11 1.4F-5
- 1. l E--G 1.3E-6 7.0E-7 4.5E-7 3.3E-7 1.2E-7 4.6E-8
- 2. 7 E-8
'1.3E .. di- / 2.2E-7 1.4E-7 9.7E-8 3.5E-8 1.4E-8 8.3E-9 4.4E HNE ilE 2.8E-7 4.lE-8 2.1E-8 1.4E-8
- 1. 0 E-8 8.2E-9 4.1E-9 2.lE-9 1.4E-9 8.2E EHE 3.1E-7 4.6E-S 2.3E-8 1.5E-8 1.lE-8 9.lE-9 4.6E-9 2.3E-9 1.5E-9 9.lE E
3.1E-7 4.6E-8 2.3E-8 1.5E-8 1.1E-8 9.lE-9 4.6E-9 2.3E-9 1.5E-9 9.lE ESE 1.6E-7 2.4E-8 1.2E-8 8.lE-9 6.lE-9 4.9E-9
- 2. 4 E-9 1.2E-9 8.1E-10 4.9 SE^
0 0 0 0 0 0 0 0 0 0 SSE 2.0E-6 6.1E-7 2.0E-7 1.1E-7 7.2E-8 5.2E-8 1.9E-8 7.3E-9 4.2E-9 2.1 s S '2.0E-6 6.1E-7 2.0E-7 1.1E-7 7.2E-8 5.2E-8 1.9E-8 7.3E-9 4.2E-9 2.1 SSW 3.9E-6 1.2E-6 4.0E-7 2.2E-7 1.4E-7 1.0E-7 3.8E-8 1.4E-8 8.1E-9 4.0 SW 3.lE-6 9.3E-7 3.1E-7 1.6E-7 1.lE-7 7.6E-8 2.7E-8, 1.0E-8 5.6E-9 2.7 WSW 1.BE-5 5.4E-6 1.8E-6 9.7E-7 6.3E-7 4.6E-7 1.7E-7 ' 6.3E-8 3.6E-8 1.8 W 2.lE-b 6.5E-6 2.2E-6 1.2E-6 7.7E-7 5.5E-7 2.0E-7 7.7E-8 4.4E-8 2.2 os WNW
- 2. 4f-5 7.3E-6 2.4E-6 1.3E-6 8.,4 E-7 6.2E-7 2.3E-7 8.8E-8 5.0E-8 2.5 NW
~"'l.8E-5 5.5E-6 1:8E-6 1.0E-6 6.[E-7 4.7E-7 1.7E-7 6.6E-8 3.8E-8 1.9 NNW 1.7E-5 5.2E-6 1.7E-6 9.0E-7 5.8E-7 4.2E-7 1.5E-7 5.9E-8 3.4E-8 1.7
- No wind in this sector for the period.'-
101 stances arn measurert from a noint mieliw liciwer n tiin react or ion iliii nn.-
Table 3. Average downwind meteorolo0lcal dispersion values (T/7) for different locations for secomi 1.ime perimi (it.ir. 20 (o a.m. ) 1.o star. 29 (4 a.m. )), sec/m 8 Downwind Distance, miles
- direction 0.5 1.0 2.0 3.0 4.0 5.0 10.0 20.0 30.0 50.0 f3E-8 N
1.8E-5 5.5E-6 1.9E-6 1.0E-6 6.7E-7 4.9E-7 1.9E-7 7.5E-8 4.4E-8 NNE 2.GE-5 7.9E-G 2.7E-6 1.5E-6 1.0E-6 7.3E-7 2.9E-7 1.2E-7 6.9E-8 3.6E-B HE 2.1E-5 6.3E-6 2.1E-6 1.2E-6 7.9E-7 5.8E-7 2.2E-7 9.0E-8 !i. 3E-8 2.8E-8 ~ ENE 1.GE-5 4.9E-6 1.7E-6 9.2E-7 6.1E-7 4.4E-7 1.7E-7 6.9E-8 4.1E-8 2.1E E 1.1E-9 ,.- r " i l' -5 G.0E-7 4.0E-7 2.9E-7 1.1E-7 4.6E-8 2.7E-8 ' 1. 4 E-8 ESE 1.5E-5
- 1. 4 E r, 1.5E-G 8.3E-7 5.5E-7 4.0E-7 1.6E-7 6.3E.8 3.DE-8 2.0E-8 SE 2.11:-5
- 6. 31 -n 2.2E-6 1.2E-6 8.2E-7 6.0E-7 2.4E-7 9.9E-8 5.9E-8 3.1E-8 SSE 2.2E-9 c 5r
- 2..'E-G 1.3E-G 8.5E-7 6.2E-7 2.5E-7 1.0E-7 6.1E-8 3.2E-8 5
2.9E-5 8.7E-6 3.0E-6 1.7E-6 1.1E-6 8.3E-G 8.3E-7 1.4E-7 8.1E-8 4.3E-8 SSW 2.6E-5 7.9E-6 2.7E-6 1.5E-G 1.0E-G 7.4E-7 2.9E-7 1.2E-7 6.9E-8 3.6E-8 SW 2.5E-5 7.4E-G 2.5E-G 1.4E-G 9.2E-7 6.7$-7
- 2. 6 E-7,,,
1.0E-7 6.0E-B 3.1E-B WSW 2.7E-5 8.0E-6 2.7E-6 1.5E-6 9.8E-7 7.2E-7 2.7E-7 "1.1E-7 .6.3E-8 3.3E-8 os W 2.7E-5 8.1E-6 2.7E-G 1.5E-6 9.9E-7 7.3E-7 2.8E-7 1.1E-7 6.5E-8 3.3E-8 rv[ WNW 2.7 5 8.0E-6 2.7E-6 1.5E-6
- 9. 8p7 7.2E-7 2.7E-7 1.1E-7 6.3E-8 3.3E-8 NW 1.5E-5 4.4E-6 1.5E-6 7.9E-7 5.2E'1 3.7E-7 1.4E-7 5.5E-8 3.2E-8 1.7E-8 NfM 1.6E-5 4.9E-6 1.6E-6 8.9E-7 5.9E-7 4.3E-7 1.6E-7 6.6E-8 3.9E-8 2.1E-8 W
ADlet9n..sc ten enn a r e tt*n t l from -s n.. I n f m 4.I..e o.e S.a I. ea a n 4 8.a .= a. r= & a.- Iso l l e4 I m a e
Table 4. External exposure from naaXe releases for close-in locations, mrem
- First Time Period Second Time period Downwind Distance, miles Distanco, miles direction 0.5*
1.0 2.0 3.0 4.0 5.0 0.5 1.0 2.0 3.0 4.0 5.0 N 200. 57.0 18.0 9.8 6.3 4.6 39.0 12.0 '4. 2 2.2 1.3 1.1 =. NNE 71. 20. 6. 3.1 2.0 1.3 57. 17. 5.9 3.3 2.2 1.6 NE 3.9 .6 .3 .2 .1 .1 46. 14. 4.6 2.6 1.7 1.3 ENE 4.3 .6 .3 .2 .1 .1 35. 11. 3.7 2.0 1.3 .9 E 4.3 .6 .3 .2 .1 .1 24. 7.0 2.4 .l. 3 .0 .6 ESE 2.2 .3 .2 .1 .1 0 33. 9.7 3.3 1.8 1.2 .9 h SE O O O 0 0 0 46. 14. 4.8 2.6 1.8 1.3 \\ SSE 28. 8.5 2.8 1.5 1.0 .7 48. 14. 5.1 2.9 1.9 1.4 x I S 281 8.5 2.8 1.5 1.0 .7 64. 19. 6.6 3.7 2.4 ' l.8 SSW 55. 17. 5.6 3.1 2.0 1.4 57. 17. 5.9 3.3 2.2 1.6 SW 43. 13. 4.3 2.2 1.5 1.1 55. 16. 5.5 3.1 2.0 1.5 ty, WSW 250. 76. 25. 14. 8.8 6.4 59. 18. 5.9 ' 3.3 2.2 1.6 4 cys W 290. 91. 31. 17. 11. 7.7 59. 18. 5.9 3.3 2.2 1.6 [)$ WNW 340. % 100. 34. 18. 12. 8.7,, 59. 18. 5.9 3.3 2.2 1.6 a NW '250.h 77. 25. 14. 9.1 6.6
- 33.
9.7 3.3 1.7 1.1 .8 Nh 240. .73. 24. 13. 8.1 5.9 35. 11. 3.5 2.0 1.3 .9 t'* Water locations are indicated by lined-out valuos. inttivleinals weiro not ovnac t ant ta li - i h--**~
N h Ln N. A Ch Ncn Ln f ..e FIG. 1. Location of fletropolitan Edison dosimetry sites for the time period Harch 28 (4 a.m.) to March 31 (4 a.m.) m
O' N fillW NNE s 15 MILE FROM N 1Cl 15GI SITE 3 f N f I NE rl' /,/ ~.4 ) ~~ 1S2 l SITE. _ 10 MILES FR '/ 16Al 2S2 m,4 '. ,,~ ~ '7, 'bb?. f WbI '~ c'. ~ &' 'W W N".1 0 'ENE 5 .,.;, j '4S2 'i ~, t I.l', 4Al 14SI N ,2 3 - 1.,.> < 3..y, -e '- i W ,ee, e ~ f. p, 1 N 'I' 2 ,{if'j,;;.: \\ 11SI 3 !l
- \\
n, a L1, ' 4; 4 SS2 h ~. 5 MILES WSW g,; 1001 ' (./f '8C1 'ESE Ln 795,, os Ys 'kbv, I 3,8 ':: 5 DS2 V N g // ,..,, n x- <,,r SW SE 19 MILES FROM R- (1,. A SITE !A 7GI
~ W tn A m Ncn N .s*, .d* "" FIG.2. Dose isopleths'out to five miles for the first time period (i.e., Mar. 28 (4 a.m.) to Mar. 29 (8 a.m.)). The innermost circle represents the exclusion boundary. Jion-occupational exposure was not expected within it.
5 O m 8 d $EEEEE w g sg gsssss =nse=" = = W GI) W v z M Cf) m .o e Z Z N f ~,1 s / "o z S / = n zj .v 7 E @\\ / 3 v: O C E -a 3 3 z .gr 3 m z g 3 3 1546 258 )
n = 4 e N \\ u, r 6 N U7 m . <..,,1, Doso isopleths out to five miles for the second time period (i.e., lla.. 29 (8 a.m.) innermost circle represents the exclusion boundary. FIG. 3. to Mar. 31 (4 a.m.)). The lion-occiipational exposure pas not expected within it. I
e ou.=sssss = P,W W W_ $ s m asssss m 2 m $ o c ri c '. = N m 3 m_eenne m h v g m z s n c. W N g 0 G w QN f h I o.e \\, \\.!I. .1 ~ 9 \\\\ m J I e I i og,,\\ s o 5 l , z f# TCPg ( m .[ '
- i3 i
~ .,,. =n 2 c. \\* N / a m v= c = / / z= + i ~~.w y' j .~ 1,c: \\ (( ~ N./ a. 3 z a g 1546 e
u e. REFERENCES (1) During the period from March 28, 1979 until May 28,1979.(except for 8 hours on April 28) the TMI Technical Specifications for instantaneous discharges were not satisfied. On May 2,1979, the station was once again in full compliance with the THI-TS for instantaneous discharges of I-131. (2) Data obtained from GeLi analysis of charcoal cartridge from Unit 2 Station Vent ~~ (HPR-219) for a sampling period of 1.73E+5sec (1900, 3/28/79 to 1900, 3/29/79). 1111s was the highest measured release rate during the period. (3) Data obtained from GeLi analysis of charcoal cartridge from Unit 2 Station Vent (HFR-219) for a sampling period of 3.6E+3sec (1300, 4/14/79 to 1400, 4/14/79). This was the highest measured release rate during the period. (4) From Table 4.4, Pickard, Lowe and Garrick, Draft Assessment of Offsite Radiation Doses Following the TMI Unit 2 Accident (TDR-TMI-116). The instantaneous release rate was extrapolated from TLD measurements made during the period (0700, 3/28/79 to 1600, 3/29/79) 1.19E+5sec. The activity of the noble gases released during this period was estimated to be 6.6E+6 curies. 1546 26i / 6 k e O W}}