ML19220C976

Preliminary Estimates of Population on Dose & Health Effects

ML19220C976
Person / Time
Site:	Crane
Issue date:	04/15/1979
From:	Battist L, James Buchanan, Congel F Office of Nuclear Reactor Regulation
To:
References
NUDOCS 7905160129
Download: ML19220C976 (75)

Text

{{#Wiki_filter:' e = p - 3 *2 6 PRELIMINARY ESTIMATES of POPULATION DOSE and HEALTH EFFECTS e Three Mile Island Nuc1.ar Station Unit No. 2 Accident Ad Hoc Intercency Dose Assessment Grouc Lewis Eattist Nuclear Regulatory Co.tmission John Buchanan Nuclear Regulatory Commissica Fraak Congel Nuclear Regulatory Commission Christopher Nelson Environmental Protection Agency Mark Nelson Center for Disease Control Department of Health, Education, and Welfare Harold Peterson Nuclear Regulatory Comission 5!arvin Rosenstein Fesd and Drug Acministration Cepartment of Health, Education, and Wel f are Easter Sunday - April 15, 1979 7905160l$4 O J

r TABLE CF CCNTENT5 i. Preface i' Su mary of F4 ndings 1. Introduction 2. Nature of the Radioactivity Released 3. External Exposure 7esessment A. Grcund Statica Dosimeters B. Onsite Metropolitan Edison Cosimeter-; 4. Potential Health Impact of External Exposure A. Health Ef fects frem Low-level Ionizing Radiation 3. Comparison of Individual Joses with Natural Background C. Comcarison of siealth I.rp;c;,ith Nctural Cancer Rir ss 0. Summary of Health tffects E. Dose Rate Effects 5. Other Sources of Exposures A. Skin Dose 8. Inhalation Dose q k k 9 n rgUU" C. Airborne Radiciodine Concentrations and Doses C. Ingestion of Iodine-131 in Milk Appendix A - CCE Estimate of External Whole Body Radiation Exposure to Population Around the Three Mile Island Nuclear Station Appendix 8 - DCE Environmental Ce:osition Measurements in the Area Surrounding the Three Mile Islar.d Nuclear Power Staticn

a e PREFACE This report was prepared by representatives of the NRC, HEW ard EFA, which cons.itute an Ad Hoc Pcpulation Dose Msessment roup. !! is 'n assessment of the population dose estimates' for the offsite residents within 50 miles of the Three Mile Island Nuclear Station. The report is being made available 3t this early date to provide details of the group's analysis and to feste coc':ent f ccm a wide spectrur' o f interested parties. The report is being released in preliminary 'orm and has received no internal review in cny of tN three.gencias 'eyond the reasonable care taken by c the mem0ers of the Ad Hoc Group to assure that the material included,is correct, to our :ncwledgm 7ne dose and health etfact.s esteutes are cased en : nose data that permit direct evaluation of dose to the offsite population froa radio-activity releas'd into the er.viron: cent during the accident. The report also addresses several areas of cui:rern that have bcen voiced publicly about tha types of radionuclides releasea, about the con-tribution to populatica dose from beta dccays of the radnuclides released, about the degree of coverage af forded by available radiatt.n reasurenents, and about the r_nge of risk factors that can be used to convert collecti'.e dose to projected health effects. 1,19 003

At this point assessment, the cerclusion of the Ad Hoc Group is that the of fsite population dose asscciated with radioactivity released during the reactor accident to date represents minimal ricks of additional health 2f fects tc the cf f site papalation. The r.urariual statemant of this conclusicr is developed in the report. The Ad Hoc Group is not aware of any radiation measure.ents made during the accident that wculd alter this basic cenclusion, althcuch refine.aent of the numrical estimates can be expected as the data are updated. The members of the f.d Har Grcuo cencur that the manner in >,hich the estimates were generated frcm the dosimetry data was ccnservatisa. "KNOWLEDGPENTS The Ad Hoc Grouc acknowl m;as the assistar.ce of Tec Scrcennarg of the Department of Energy ana Ancy '"uil sf 3rocKnasen :iational Laccrnory in oroviding the preliminary assessment in Appendices A and S. We especially acknowledge the contribution of Mrs. Jeannette siminas of tne Nuclear Regulatory Commission staff in preparing this material on such sncrt notice. 119 00?1

PRELIMINARY ESTIMATES OF POPULATIGN COSE AND HEALTH EFFECTS Three Mile Island Nuclear Station Unit N0. 2 ".ccident Summarv of Findings An interagency tee, f rca HEW, EFA and NRC has estimated the collective radiation dose received by the approximately 2 million pecple res: ding within 50 miles of the Three Mile Island Nuclear Statico resulting from the accident of March 28, 1979. The estimates are fac the period frcm Marc, tu through April 7, 1979. The principal dose estimate is based cpon ground level racia-tion measurements f: a inteyating cosimeters lccated witnin 15 miies of tne site and represen;s only the gr a-ray ccmponen er tne raciatica exposure The data were cbtained frca dosimeters placed by Metropolitan Edison Pcwer Company prior to the start of the incident through Parch 31, 1979, as part of their normal environnental surveillance program, and frca measurements made by NRC frca neon of March 31 through the af terncen of April 7,1979. A second dose estinate, develcped independently by the Department of Enerc .hrough aerial monitoring that ccamenced about 4 p.m. on March 28, 1979 ja also included. A variety of other data helpful in assessing other relatively miner components of population dose was also reviewed. C \\ \\ 9 o rd.) a

f 4 2 The hignest raaiation measurement that is applicable to the offsite popula-tion occurred in an area east to northeast of the plant. The maximum indi-vidual dose to a hypothetical person located in this region for the duration of the incident would be about 85 mrem. The collective dose to the total population within a 50-mile radius of the plant was estimated to be about 3,550 person-rem, based on the projected 1980 population estimate. No reduc-tion in this dose estimate has been made for u significant portion of the population that relocated frcm areas close to the nuclear plant or otherwise left the area. The projected number of fatal sancers oser the total lifetime of the entire population located in the 50-mile area is 0.7. The nuccer of totai potential lifetime health effects, including all cases of cancer and genetic effects to futur? gene:'ation,,sculd be approxiaste'y 2.0. A number of cuestions concernir.g this analysis are posed and br iefly answered below. More detailed discussions are included in the body of the report. What radionuclides were released into the em iront ei t? The predominant radionuclide released into the enviro.aent was xenon-133, with some xenon-135 and small amounts of iodine-131. This conclusion is based i19 006

3 on the information available to date, which includes the expected inventory of noble gases for the period the reactor was in operation prior to the accident, analyses of airborne radicactivity in the containment structure, measured ccmpositien of stack d'scharges, arr' the exten:i va monitoring c' environmental samples. The environmental samples provide the most direct evidence for this conclusion. What wre the hichest r=diation excosures Teasured autside the ciznt buildMgg Scme of the Metropolitan Edison dosimeters located on the Three Mile Island Nuclear Station site during the first days of the accident recorded cumulative doses censicerably larger (up to 1,050 arem) thar, tnose located for of f site populations. TLe onsite dosimeter readings are not acplicacle to ei.ne-the maxi mc: dose to an indivicJal offsite nor the.oilective (pcpulation) dose. What is meant by maximum dose to an individua], The maximum dose to an individual applies to a hypothetical person expcsed out-of-doors in the area of the maximum recorded axposure readings recorded for an offsite locaticr, throughout the period of the incident. It applies only to that individual or others in the same vicinity and not to any other population segment. 119 007

4 what is meant by collective dose (ce" son-rem)? The collective dose is a measure of the total radiation dose which was received by the entire populatico in the 50-mile radius of the Three min Is' cod site. It is obtained by multiplying the number of pecple in a given sector of the area by the dose estimated for that sector and adding up all of the sector totals. How were the of fsite ccculatic ' dose estimates obtained? The pr1 Jal population dose estimate was obtained by analysi s of data from integrating dosimeters placed at fixed locations at various distances offsite. During the pericd March 23 thrcugh trch 31 there sere a limited numcer of.'<et: pc. itar Ediaan ;'fsite dosimeter locations. During the period af ter March 31, NRC placed 37 dosimeters at of fsite locations. On Aoril 5, 10 cdditional NFC dcsimeters were placed of fsite at selected schcoi locations. Af tar March 21, c71y the NRC dosimeters were retrievcd for analysis. These dosimeters record the contribution to excernal radiation exposure fror gamma rays emi.ted from, radionuclides. A second analysis which results from DOE aerial surveys of radiation exposures Teasured in the plLme of the radiation releases was also availab'e. 119 003

a 5 Were the radiation aasurements adecuate to determine occulation health effects? The extensive environ ~ertal nonitori ng and food :,'mpling were adequuta to characterize the nature of the radionuclides released and the levels of radioactivity in those media. The dosimetry work performed by COE (aerial survey) and Petropolitan Edison and NRC (ground level dosimeters) are suf fi-cient to characterize the maximum individual and population dcse, when taken as a whole. The number and location of fixed ground level dosimeters for the period March 28 through March 31 was 1;mited. However, this pericd was covered by aerial monitoring frca abcut 4 pm on March 23 by the DPE aerial survey and by mobile ground Tonitoring surveys performed by various organizations frca about 10 am en " arch 23. What is the contribution of beta radiation ' emitter fron xenon-133 to the total dose? The beta radiation from xenon-133 can contribute to radiation dose by two acdes, inhalaticn and skin absorption. The los energy of tr.a xenon-133 beta cannot penetrate past the skin layer. The te*.al beta plus ga.ma dose to the skin is estimated to be about 4 times the total body dose frca gamma radia-tion alone. This additional skin dose could result in small increases in the total health effects (about 0.2 health effects) due only to skin cancar, The increase in tetal fatai cancers c/er that estimated for external exposure i19 00c!

5 from gamma radiation alene would be about 0.01 fatal cancers. This contricu-tion would be considerably decreased by clothing or by being indoors. The dose to the lungs from inhalation of xtnon-133 for both beta and gamma is estimated to be acproximately 1 percen; of that for total body dose from gamma aiore. The cose to ail body organs from inhalation of xenon-13J is acproximately 4 percent of that for total body dose from gccma alone. What radionuclides were 'cund in milk and fcod and what are their sig_nificance? Iodine-131 was detected in milk sanales. The maximum level seen in milk was 3:0 times lower than the level at which a recommendation would be made to re eve cows fecn ccntaminated pasture. Cesiem-137 was aisc netected ir miik, but at concentraticas anticipated f rom residual f allout from previous atmospner 'c weapons testing. No increase in radicac ivity was found in any other food samples. How were the health effects estimated? Health effects were derived from risk facters generally accepted by the scientific ccmmunity to be the best estimates of health effects f rcn loa-level radiation exposure, using the conservative linear, ncn-threshold dose effect model. These risk factors are multiplied by the collective dose (person rem) to obtain health effects. O nin / U.V

4 7 Have the estimates of radiation dose and health effec s chrr;ed since tp fit st statement on Acril 4 at the Senate Hearincs? The maximum dcsc to an individual has ic:reased from 30 to 35 m. rem, as a consequence of adding the contribution fron April 2 to April 7. The estimated collective dose to the population has almost doubled from 1800 person-rem to 3,550 person-rem. This incr-e is due to a more thorough and systematic review of the earlier dosimeter results and to the dose contribution frcm April 2 to Acril 7. The increase in collective dose changes the existing risk of fatal cancers to the 50-mile radius pcpulation frc': 0.35 cancers to 0.71 cancers. In either instance less than one additional fatal cancer is anticipated. The change in lifetime risk for all cancers and genetic effects is increased frca a;croximately 1 to a: proximately 2. These changes therefore c'o not alter toe previous conclusion of minimal health effects to the entire offsite population from the radioactivity released during the accident. What does the term "creliminary estimate" mean? The dcse and health effects estimates contained in this report are based on those data provided the NRC Incidence Response Center before April 7, 1979. There has not been sufficient time to verify many details concerning the data and to incorporate later updates on the results. While the Ad r cc Group feels i that the overall conclusion that there was minimal health impact t: he copula-tion is correct, the actual numerical values may be subject to change. 119 011

8 1. INTRODUCTION The ^,d Hoc Pcpulation Cose Assessnent Group was formed frca individuals assigneu.. their respccti,e agencies to the NRC Incident Response Center on Monday April 2, 1979 and who recognized a common need for an estimate of the public health consequences of this accident. Because of the urgency to prepar' estimates of the nealth impact fer presentation at the April 4, 1979 fenate hearings, the group was forced to rely upon data which were available at the NRC Incident Response Center or easily obtained through existing communication channels with the r deral e coordination center adjacent to the Three Mile Island site. This preliminary recort presents the analysis performed at that time, with an extension of the estimate through April 7, 1979. The Ad Hoc Group has also haa a chance to review its earlier calculations and analyze the data in a T. ore systematic fashion. },19 n19 U.-

9 2. NATURE OF THE RADI0 ACTIVITY RELEASED The primary r.'dioactive materials released to the environment appear to be xenon-133 (hal f-life 5.3 days) and xenon-135 (half-life 9.2 hours) and t aces of radioactive iodine, primarily ioa;..e-131. This is substantiated by consicera-tion of the known course of events, kr.awledge that the ef fluents were released through particulate and iodine filters, and from subsequent environmental measure-ments in the diffusing radioactive plume (see Appendix 3). Particulate radio-nuclides such as strontium-90, uranium isotopes, and plutonium would eitner have been retained in the feel or if released from the fuel would remain in the coolant water. These elements have not, to our knowledge, been detected in the environment in the vicinity of Three Mile Island nor in the reactor containment cr gas decay tanks. Radioactive krypton isotopes, which would ordinarily be expected to be released along with the xenon isotopes, do not appear to have been released in comparable quantities. This may be due to the relatively short half-life (seconds to minutes) of their precursors, compared to the hour to several day half-lives of the radioactive iodine parents of the xenons. The majority of the krypton isotopes appear to have remained within the containment building. Appendix 3 describes the environmental surveillance activities of the Cepartment of Energy which measured the radionuclides in the environment frca the release.

10 3. EXTERNAL COSE ASSESSMENT A. Analysis of Metropolitan Edison and Nuclear Regulatory Commission Ground Dosimeters The available tnermoluminescent dosimeter (TLD) data were used for this evaluation due to three primary facto: s: 1. The TLJ's placed by the licens:e as part of the environmental radiation surveillance program for routine operation were the only devices for measuring radiation exacsure that were placed at fixed locations throughout the course of the accident, parr.icularly during the first 3 hours. 2. The TLD's are dose integrating devices and measure total exposure rather than peak exposure ates which may be transient (of short duration). 3. Under ideal conditions (which may or may not apply to this situation) they can measure exposures of a few mR (1,2). (1)Artnur Schambon, "Some Implications of LiF Dosimeters for Envirormental Radiation Measuremeats," U.S. Atomic Energy Ccmmission Report HA5L-251 (" arch 1972). (2)Gail ce P. Burke, " Investigation of a CaF :Mn Thermoluminescent Cosimetry 2 System for Environmental Monitoring," U.S. Atomic Energy Commission Recort HASL-252 (April 1972). 119 014

11 Samples of each type of TLD placed by the various organizations around the TMI site 8, ave been collected and exposed to known doses from a calibrated source of xen.in-133. The results of this calibration were not completed in time for consiceration for th'o preliminary report. TLD data available for the dose assessment are listed in Tables 3-1 through 3-11. The locations of these dosimeters are shown in Figures 3-1 ana 3-2. Data for the first two periods 3/28-3/ 29 and 3/29-3/31 were cbtained frem stations used by the Metropolitan Ed: son for their routine environmental monitoring program. Table 3-1 contains data from both a monthly and a quartarly sampiing program. The quarterly data were adjustad for an assumed 14 mR background to calculate the TLD exposure. Since an approcriate background correction to the monthly data could not be determined, those values were not adjusted. The data were ordered according to sector. Those net dosimeter readings which are frca onsite locations are identified with an asterisk in the table. Since these locations were subject to direct radiation and to high local concentra-tions of xenon-133 they were nct considered apprcpriate for estimating offsite doses for the collective dose calculations. The net offsite data within a sector were avercged and are listed in the last column of the table. These exposures are assumed to be representative of those received at distances up to 10 miles. Exposures fcr sectors without observation were obtained by interpolation from adjacent sectors, \\k9 n*r UiJ

12 Since there are data for only 6 offsite locations in 6 sectors, the assess-ment for this first period rests on a very small data base. Metropolitan Edison data for 3/29-3/31 are summarized in Table 3-2. Data for these cbservations were provided in units of mR/hr for undesignated time periods which ranged frca 36 to 48 hours. The total exposure for the period was calculated assuming a 44-hour period for each exposure. These data for the period 3/29-3/31 provide observations for 11 locations in 9 sectors. The increased coverage represents an improvement for purpose of the dose estimation over the previous period. Descriptions of the station locations are presented in Table 3-3. Cata subsecuent to March 31 were obtained frca the NRC dosimeters and are summarized in Tables 3-4 through 3-10. The locations of the NRC TLD's are summarized in Table 3-11. The background assumed for these statienc is 0.19 mR/ day based on an average of TLD data from the 1977 Environmental Monitoring Report (3). Maximum Dose to an Individual The estimated maximum dose to an individual is tabulated, as a function of time in Table 3-13. (3) Metropolitan Edison Ccmpany Radiological Envircnmental Monitoring Report - Three Mile Island Nuclear Station - 1977 Annual Report, January 1 through December 31. 119 0)

13 The maximum dose (4) to an individual was estimated for the period 3/28-3/29 as the mean of the TLD exposures of two onsite locations, North Weather Station (152) and North Bridge (252). While no member of the general public was present at either location, they represent a best judgement of the maximum to which any individual in the general northerly to easterly direction or the plant could have been exposed. The TLD exposures were corrected for background (14 mR) and the do'e in mrem assumed to be equal to the exposure in mR. For the period 3/28-3/29 the maximum individual dose was thus estimated to be 45 mrem. For the period 3/29-3/31 the maximum individ"31 dose was increased by 29 mrem, the exposure recorded by the dosimeter of station 4A1. Subsequent addition to the maximum individual dose are based on the exposure corrected for background at NRC station ElA. The total dose for the maximum individual is 36 mrem for the period 3/23 through 4/7. This value is considered a conservative upper bound. Collective Dose The collective dose was estimated for the population within 50 miles of the plant. The population data used for the estimate were the 1980 projeuted (4)The term "cose" is used here for brevity rather than the precise term " dose equivalent." 4 7 \\\\

14 populations given in the SAR(5). These population distributions are contained in Tables 3-12 and 3-13 cocering 0-10 miles and 10-50 miles respectively. The collective dose in person-rem for each directional sector was calculated as the sum of two parts. The first part 'aas the product of the average 0-10 miledoseandthe0-10milepopulation. The second part was the product of the corresponding 10-50 mile values. The 0-10 mile dose for each sector was based on the corresponding nel TLD observations assuming that the dose in mrem was equal to the TLD exposure in mR. For all but the first three periods, net exposures for each TLD in a sector were averaged to obtain the 0-10 mile dose. For data during the first three periods, an attempt was made to make the estimates more realistic by adjusting each TLD observation to a 5-mile distance assuming an inverse 1.5 power Gependence with distance. Dosimeters within 1 mile were assumed to be at 1 mile as a conservative assumption. For example, in the 3/28-3/29 period there are two net observations of 8 mR in the SE sector. Since they are at distances of 9 and 15 miles, the 0-10 mile dose is estimated as (3 x (5/9) 1.5 + 8 x (5/15) 1.5)/2 = 30 mrem. The 0-10 mile dose is given in the last column of Tables 3-1, 3-2, and 3-4 through 3-10. (5) Final Safety Analysis Report, Three Mile Island Nuclear Station - Unit 2, Vol.1, Chapter 2, Figs. 2.1-5 and 2.1-10. 119 010

15 The 10-50 mile dose is obtained by assuming a standard dispersion factor that decreases with distance to the -1.5 power. The 0-10 mile dose is used as the reference dose at 5 miles and the population is assumed to be uniformly distributed within the sector segment. On the basis of these assumptions tne 10-50 mile dose is.0728 times the 0-10 mile dose. The collective doses are summarized in Table 3-15 for each period of data. The estimated total collective dose for period 3/28-4/7 is about 3,550 person-em. More than half the collective dose calculated was delivered before March 31. Unfortunately there are very limited data in this period to use for this estimction. The total value of 3,550 represents a reasonable estimate, in our vies, but is clearly limited by uncertainties due to the limited data available for the period 3/28-3/31. Further refinement of the values used will not reduce the uncertainty due to the limited number of observations available. 119 019

Figure 3-1. Location of Metropolitan Edison Dosimetry Sites (March 9.8-31) and Nuclear Regulatory Commission Sites (After March 31) Within a 10-mile Radius of Three Mile Island Nuclear Station. See Figure 3-2 for Metropolitan Edison Sites within One-mile Radius. MetrocolitanEdisonDosimeters(uptoMarch31)[_T ~ o NRC School Dosimeters (Af ter April 5) A NRC :: simeters (Af ter March 31) l I g U <_ q 1 07 1 v

. n..~ p s- <%,,-,.,,Jc >;

• ' % ',S.L.g, d

v' . ' ~c--- .. -e -. P k;Y' Q 4 2.,, &R. ,, %s,'. 'k ' * '. '. _ _c, # l I .**,e, "QD .,'( \\ ',%~ Q\\ ./. ' i , = * * 'c r, - Q f,,, '. -.i.,.s' s s. 4 u- .,.s. 1. .v.,.',.. x.3. q"'.,d,, l;,e s m ik.. t.;0, 1 i 'u A

• ~~ '*,...N* y ~*. e

.s s. 3 3 js %.y ,o {,~~/'.e s-v",'s* Osy. , f u.W.,T3. \\ r - &l, e } ~ ' ~s ^~ f

• **-=' t 'f '

,M \\ --- R e -~,'.. " ~ ! s v . s u .. s

• - Y1

.C-2/$,3c-i'.* ;,, ', b_,,, Q,; ' j _, j bV..Ii -/21 b, %, '. 1. V :~f, 4-J I j

a. :@.

3

r.

• w--w au.

.:~*.:. m.. ,j.' 1 - **.-_4. . g-. * -~ s a q. u.., r'.:b,-g,;L , N. _.,_, y, -? ns s i 1 .3 A' 1 ,..,6_.4_ 4 ..wc -

m~ w..N w.

s. w,

7

.,e. ...-4 3 i 1 0.. i , 4.:,.. <..: &,,,, n.

c.,

i , a .. )4- .~: -w- - - ~ ~ v~.. , [ -- 4 q r + s .hh~ y..s'$b' s _, .Z'\\ ? f ?.=w f ay u'd GW, ,'1.?K $gl .w:: & '- 6 : f t'y.i. w w. 4'% ~ \\ ' --r y~ .g+. ,o dd 3 M i @};. m - . pI ~p;u} - fe..

• G u M' ~

~p. ' :. r y 'y +'- ~ ,.W %. ..g5,<'-:y %sQ '"%,k % % -;ii"~'.. if, A.9 y,4; '5 %. 4i Ln u. r h, e'1.~m,_f,.h:q d. e.'hih', t 6.,.o.-,.esd ffM h F -)/,/. S

1.,.

~., m

• '1,.

. W.[ ; M \\.\\ l-D" ','i,, t ~, s- ' ' ' O. ~ Y v . f,*g. -.>,%,a. l'4. , %( '. s ty c. , Aw q. r .c r a u s .s. ~ > j, .p a e,,5 fm - %. g w. 4.M~*K ( s, e ' y l, I 'b"r3. 7'ug:. a\\

• z#" 4

.-Q'..:. . y ',;f G ^ ,T..,p9 d .C.o.>; y ' M;. y s., / '\\ y' e. w s ,c p. wi. q N-t N. Z A,+ - A .,. o ' gijl 4 *c at Q.,>. -n,.Qs. 1 C @\\a.- %;E.V-QMg.q sMMgf. gym %).' &- b:, 3 e-f 9 %g y% n ,v + g s# c ,K W;R f. &: g::4= m w }t. M ^ %, 2 M W M % b h n '" ' ' f 'i r. i ~.x _. % '2 M4 m w. 4 w.x i.,bn. m..., s. %, n,,, ..i.y,.

4..

.y. , s_~ t g., w< ew b k li h f Q%~Q '?.& y O'$ $ fd,,'.WC-E% % % 4 EdhqMYg3di$m.. p MfM Mccr%@WsR VQMq : m o-o g -[._han ... - - w s.. w m mg,. m.. w. . s k hbh},c, F:.b.h Y} hkk{.w b 7-_Yh??5NT .yv t 2.. a y-. h*9L kY C%%w&e[v' g ' iE W = W ':s.:q w m'sm. A eies DV. b;U.:32fM j ,d[Q:.'? m& % % Y.n.--% W.&'5W29-$a$%t?a$.?2=% . a. v#^ r c . s f'~f. .k h'. ,,,% %w. s &j i ~ ',, men.:. " ' % - A.:- f' ~~'l' f

• u. ' m'1 c W'

^ %. w' .:.y mq r am' grl.N;% u%mW~.:+3 X%p y~ pg:noy;;;w '&s,.

n m;>

w e w. h }> u m e r w a A L2--,.1.;Mr h t::~- A Q s y -g 1 4.~ M Bir j E; WR b h b i 4 m g w % g 4 h, w % % g gs % M.-- w ' q.,, a,- w w 2 yn., h 743,3 8 4j p $m@a?p'.%7:.v iC 4.t.Ly W .p. .g-- t p'24 Jya,c @;M'w.,; ' mdr A~n;g. p--- 6 ^ w=mm, _ m'W" w w%p.-p+ 9 u w- ... u.]k , ' 5". .s A ya +,,r -

<,M v. W ; /..q a.-

g n - m... y . s.c - e W yv1 e -n m 9; . e ----- u%p. mg,:d, C%.&w +,. x :,. se p,,.. 9:u,~.m; q., W %i ,~g,.,Q A A N.%u. _.-c. : <. _m., g- > v s t,.n ~ c-; tx w v 3 a g -~ s h,~~. .,h@e,4 -k.c.- -. h. w - w n. ~[,<, 5 . M,. n. h ,3 7 H A ,if$ O . ~. w. m s. _. h. ~h ' g .%,. v ~h. #[e'.FA.1,, h,.- db5 N h. %.s, . - m l., -p ^ s;r.,J m'. t.h ; k s df ,~~ ,q N5-\\' g ~ '"h 'd /* Ma. 5?fW'h e - e,.w' a.. g j g 9A i w 4,' n'+--

• & - We,, y.,..

~m J 3 M. Y 51 Y;.- Zy-s*;c- :!., ,...?-Lium%: --,\\ ' ' '%e -- .w 1 T. - Q ' &,L&nd.RC =&, s, -t% 'y b?l'&

• 'hW.,y =

v r,a M..: ' &^^jfh '3 ?W'~, thy $&b:. . W m g kyg & M-g.M a n$ @;n

16 Table 3-1. METROPOLITAN EDISON TLD DATA 3/28/79 - 3/29/79 2 TOTAL NET 0-10 MILE DIR STATION LOCATION PERIOD' EXPOSURE EXPOSURE DOSE (mR) (mR) (mrem) N N. Weather Station (.4 mi) Q 81 67* 0.56 N. York Substation (1.4 ai) Q 9 0 Middleton Substation (2.6 mi) Q 17 3 NNE N. Bridge (.7 mi) Q 37 23* (1.)4 NE (2.3) ENE Laurel Rd (.5 mi) Q 17 3 3.1 Rte 241 M 6 6 E Obs. Center (.4 mi) M .5 .5 0.05 ESE (15.0) SE Drager Farm (9 mi) M 8 8 30.0 Columbia (15 mi) Q 22 8 SSE Falmouth (2 mi) Q 12 0 0.0 5 (0.02) SSW Shelley Island, south Q 7 0* (0.04) (1.1 mi) SW (0.06) WSW (0.08) W West Fence H 6 6^ 0.09 Shelley Island ctr. (.4 mi) Q 7 0* Goldsboro (1 mi) Q 15 1 WNW Shelley Island, north (.4 mi) Q 7 0* (0.21) NW (0.32) NNW Kohr Island (.4 mi) Q 8 0* (0.44) IQ - Quarterly data (assumed bkg is 14 mR) M - Monthly data (assumed net) 2Values in parentheses are interpolated. Onsite locations not used for offsite dose assessments. g r{"f

17 Table 3-2. METROPOLITAN EDISON TLD DATA FOR 3/29/79 - 3/31/79 1 2 DIRECTION STATICN CODES TOTAL EXPOSURE 0-10 MILE COSE (mR) (arsm) N 152, 1C1 17.3*, 3.0

1. 0 NNE 252 28.2*

(1.7) NE (2.4) ENE 4S2, 4A1, 4G1 105.6*, 28.7, 1.4 3.1 E 5S3, 5A1 42.3*, 7.2 0.6 ESE (2.6) SE 7G1, 7F1 1.8, 1.2 4.5 SSE SC1

9. 7 2.9 5

952, MG1 22.3*, 1.8 6.3 SSW 1081 12.6

1. 2 SW 1151 95.9*

(1.3) WSW 1281 8.1

1. 4 W

(4.2) WNW 1452 39.4* (7.1) NW 15G1

2. 2 9.9 NNW 1651 75.7*

(5.5) n Onsite locations not used in calculations. 1. Based on 44 hour period. 2. 0.3 mR background subsequently substracted. Values in parentheses are interpolated from adjacent sectors. 119 023

18 Table 3-3. METROPOLIiANEDISONTLDSTATIONLOCATIONS STATION LOCATT3N DESCRIPTICN* CODE 152 0.4 miles N of site, N Weather Station 252 0.7 miles NNE of site on light pole in middle of North Br'.dge 452 0.3 miles ENE of site on top of dike, East Fence 553 0.2 miles E of site on top of dike, East Fence 952 0.4 miles S of site at South Beach of Three Mile Island 1151 0.1 miles SW of site, west of Mechanical Draft Towers on dike 1452 0.4 miles hNW of site at Shelley Island picnic area 1651 0.2 miles NNW of site at gate in fence on west side of Three Mile Island 4A1 0.5 miles ENE of site on Laurel Rd., Met. Ed. pole #668-OL 5A1 0.4 miles E of site on north side of Observation Center Building 1CB1 1.1 miles SSW of site on south beach of Shelley Island 1281 1.6 miles WSW of site adjacent to Fishing Creek 1C1 2.6 miles N of site at Middletown Substation 8C1 2.3 miles SSE of site 7F1 9 miles SE of site at Drager Farm off Engle's Tollgate Road 4G1 10 miles ENE of site at Lawn - Met. Ed. Pole #J1813 7G1 15 miles SE of site at Columoia Water Treatment Plant 9G1 13 miles S of site in Met. Ed. York Load Dispatch Station 15G1 15 miles NW of site at West Fairview Substation x All distances measured from a point midway between the Reactor Buildings of Units One and Two. r )b } } h V)'c 'i

19 Table 3-4. NRC TLD DATA FOR 3/31/79 - 4/1/79 OIRECTION STATION CODES TOTAL EXPOSURE

• 0-10 MILE DOSE (mR)

(mrem) N N-1, N-2, N-3, N-4, N-5 1.0, (wet), 1.2, 1.0, (wet) 1.39 NNE (1.60)** NE NE-2, NE-3, NE-4 (wet), 1.6, 2.1 1.81 ENE E-1, NE-1 25, 7.0 1.41 E E-2, E-2***, E-4, E-1A 4.3, 2.1, 2.5, S.4 1.87 ESE (2.59)** SE SE-5, SE-4, SE-3 2.5, 3.0, 2.3 4.96 SSE SE-2, SE-1 3.5, 10.1 0.81 S S-1, 5-2, S-3, S-4 1.6, 1.0, 1.2, 1.2 1.18 SSW SW-1, 0.9 0.21 SW SW-2, SW-3, SW-4 0.9, 1.1, 0.9 1.45 WSW W-2 0.9 0.J9 W W-1, W-1, W-5, W-4

3. 0, 1.1, 1. 2, 1. 0 1.01 WNW NW-3

1. 4 0.53 NW NW-5, NW-4, NW-2, NW-1 4.6, 5.5, 1.2, 0.9 9.09 NNW (5.24)**

= Net mR = (Total mR) - (0.19 mR Skgd.)

== Value interpolated frcm adjacent sectors. xxx Should be E-3. 119 nnEu <_ a

20 Table 3-5. NRC TLD DATA FOR 4/1/79 - 4/2/79 DIRECTION STATION CODES TOTAL EXPOSURE

• Q-10 MILE COSE (r.R)

(mrem) N N-1, N-2, N-3, N-4, N-5 0.3, 0.3, 0.3, 0.3, 0.3 0.11 NNE NE-1, NE-2, NE-3 0.2, 0.3, 0.3 0.08 NE NE-4 0.3 0.11 ENE E-1

0. 4 0.21 E

E-1, E-4, E-1A 0.4, 0.3, 0.3 0.21 ESE E-2 0.3 0.11 SE SE-5, SE-4 0.3, 0.3 0.11 SSE SE-3, SE-2, SE-1 0.3, 0.3, 0.3 0.11 S S-1, S<2, S-3, S-4 0.4, 0.4, 0.4, 0.3 0.1.' SSW SW-1, SW-2 0.8, 0.5 0.46 SW SW-3, SW-4 0.4, 0.5 0.29 WSW W-2 0.5 0.31 W U-1, W-3, W-5, W-4 1.2, 0.5, 0.6, 0.4 0.49 WNW NW-3, NW-1 0.8, 1.7 1.06 NW NW-5, NW-4, NW-2 0.4, 0.3, 0.4 0.18 NNW (0.15)** x Net mR = (Total mR) - (0.19 mR Bkgd.) xx Value interpolateu from adjacent sectors. i19 026

21 Table 3-6. NRC TLD DATA FOR 4/2/79 - 4/3/79 DIRECTION STATION CODES TOTAL EXPOSURE

• 0-10 MILE DOSE (mR)

(mrem) N N-1, N-2, N-3, N-4, N-5 0.37, 0.45, 0.43, 0.48, 0.53 0.26 NNE NE-1, NE-2, NE-3 0.45, 0.48, 0.42 0.26 NE NE-4 0.37 0.18 ENE E-1 0.53 0.34 E E-3, E-4, E-1A 0.42, 0.4, 0.73 0.33 ESE E-2 0.55 0.36 SE SE-5, SE-4 0.74, 2.1 1.23 SSE SE-3, SE-2, SE-1 2.8, 4.4, 9.1 S.21 S S-1, S-2, S-3, S-4 2.2, 1.5, 1.5, 1.4 1. S$W SW-1, SW-2 1. , 1.3 1.06 SW SW-3, SW-4 0.78, 0.75 0.57 WSW W-2

1. 0 0.81 W

W-1, W-3, W-5, W-4 1.4, 0.78, 0.9, 0.67 0.75 WNW NW-3, NW-1 0.63, 1.3 0.77 NW NW-5, NW-4, NW-2 0.42, 0.40, 0.62 0.29 NNW (0.27)** Net mR = (Total mR) - (0.19 mR Skgd.) xxValue interrolated frca adjacent sectors 119 027

22 Table 3-7. NRC TLD DATA FOR 4/3/79 - 4/4/79 DIRECTION STATION CODES TOTAL EXPOSURE

• 0-10 MILE DOSE (mR)

(arem) N N-1, N-2, N-3, N-4, N-5 0.32, 0.40, 0.32, 0.33, 0.37 0.16 NNE NE-1, NE-2, NE-3 0.32, 0.37, 0.38 0.17 NE NE-4 0.38 0.19 ENE E-1 0.32 0.13 E E-3, E-4, E-1A 0.40, 0.35, 0.38 0.19 ESE E-2 0.55 0.36 SE SE-5, SE-4 0.42, 0.30 0.17 SSE SE-3, SE-2, SE-1 0.57, 0.87, 0.43 0.43 S S-1, S-2, S-3. 5-4 1.1, 0.52, 0.47, 0.33 0.42 SSW SW-1, SW-2 1.1, 0.37 0.55 SW SW-3, SW-4 0.65, 0.62 0.45 WSW W-2 0.62 0.43 W W-1, W-3, W-5, W-4 1.7, 1.1, 0.65, 0.42 0.78 WNW NW-3, NW-1 0.40, 0.30 0.16 NW NW-5, NW-4, NW-2 0.42, 0.30, 0.40 0.18 NNW (0.17)** n Net mR = (Total mR) - (0.19 mR Skgd. )

• • Value interpolated frca adjacent sectors i19 023

23 Table 3-8. NRC TLD DATA FOR 4/4/79 - 4/5/79 DIRECTION STATION CODES TOTAL EXPOSURE

• 0-10 MILE DOSE (mR)

(arem) N N-1, N-2, N-3, N-4, N-5 0.28, 0.33, 0.34, 0.37, 0.35 0.14 NNE NE-1, NE-2, NE-3 0.45, 0.33, 0.37 0.19 NE NE-4 0.33 0.14 ENE E-1 2.6 2.41 E E-3, E-4, E-1A 0.50, 0.43, 1.7 0.69 ESE E-2 0.38 0.19 SE SE-5, SE-4 0.37, 0.53 0.25 SSE SE-3, SE-2, SE-1 0.45, 0.38, 0.92 0.39 5 S-1, S-2, S-3, S-4 0.37, 0.32, 0.40, 0.45 0.20 SSW SW-1, SW-2 0.37, 030 0.15 SW SW-3, SW-4 0.45, 0.45 0.26 WSW W-2 0.72 0.53 W W-1, W-3, W-5, W-4 1.3, 0.42, 0.60, 0.45 0.50 WNW NW-3, NW-1 0.38, 0.38 0.19 NW NW-5, NW-4, NW-2 0.32, 0.37, 0.33 0.15 NNW (0.14)** x Net mR = (Total mR) - (0.19 mR Bkgd.)

==Value interpolated frca adjacent sectors 119 029

24 Table 3-9. NRC TLD DATA FOR 4/5/79 - 4/6/79 DIRECTION STATION CODES TOTAL EXPOSURE

• 0-10 MILE DOSE (aS)

(area) N N-1, N-2, N-3, N-4, N-5 0.32, 0.48, 0.47, 0.42, 0.48 0.26 N-1A, N-1C, N-1E, N-1F 0.50, 0.50, 0.40, 0.47 NNE NE-1, NE-2, NE-3 0.38, 0.47, 0.46 0.25 NE NE-4, NE-3A 0.40, 0.38 0.20 ENE E-1 0.50 0.31 E E-3, E-4, E-1A 0.48, 0.42, 1.2 0.51 ESE E-2 0.45 0.26 SE SE-5, SE-4, SE-4A 0.62, 0.47, 0.33 0.28 SSE SE-3, SE-2, SE-1 n.40, 0.35, 0.40 0.19 5 5-1, S-2, S-3, S-4, S-1A 0.35, 0.35, 0.40, 0.55, 0.35 0.21 SSW SW-1, SW-2 0.37, 0.43 0.21 SW SW-3, SW-4 0.38, 0.50 0.25 WSW W-2, W-3A 0.37, 0.65 0.32 W W-1, W-3, W-5, W-4 0.57, 0.38, 0.40, 0.45 0.26 WNW NW-3, NW-1 0.40, 0.52 0.27 NW NW-5, NW-4, NW-2 0.48, 0.32, 0.35 0.19 NNW N-18, N-10 0.40, 0.35 0.19 n Net mR = (Total mR) - (0.19 mR Bkgd.) 119 030

25 Table 3-10. NRC TLD DATA FOR 4/6/79 - 4/7/79 DIRECTION STATION CODES TOTAL EXPOSURE ^ 0-10 MILE DOSE (mR) (arem) N N-1, N-2, N-3, N-4, N-5 0.43, 0.4, 0.50, 0.48, 0.52 N-1A, N-1C, N-1E, N-1F 0.47, 0.45, 0.44, 0.37 0.25 NNE NL-1, NE-2, NE-3 0.45, 0.47, 0.45 0.27 NE NE-4, NE-3A 0.43, 0.57 0.31 ENE E-1 0.48 0.29 E E-3, E-4 E-1A 0.32, 0.22, 0.32 0.10 ESE E-2 0.35 0.15 SE SE-5, SE-4, SE-4A 0.38, 025, 0.25 0.10 SSE SE-3, SE-2, SE-1 0.25, 0.25, 0.55 0.16 S S-1, 5-2, S-3, S-4, S-1A 0.40, 0.43. 0.55, 0.42, 0.43 0.26 SSW SW-1. SW-2 0.45, 0.38 0.23 SW SW-3, SW-4 0.42, 0.50 0.27 WSW W-2, W-3A 0.38, 0.45 0.23 W W-1, W-3, W-5, W-4 0.48, 0.47, 0.57, 0.57 0.33 WNW NW-3, NW-1 0.41, 0.45, 0.38 0.29 NW NW-5, NW-4, NW-2 0.45, 0.45, 0.38 0.24 NNW N-13, N-1D 0.50, 0.50 0.31 x Net Mean.1R = (Total mR) - (0.19 mR Bkgd. ) i i19 n0;-

26 Table 3-11. NRC TLD LCCATIONS STATION DISTANCE DIRECTION SECTOR DESCRIPTION E-1 .5 mi 61 ENE 1200' N of E-la NE-1 .8 mi 25 NNE North Gate NE-2

1. 8 mi 19 NNE Geyers Ch N-1 2.6 mi 358 N

Middletown NE-3 3.1 mi 17 NNE Township School NE-4 6.7 mi 47 NE N-2 5.1 mi 360 N Clifton N-3

7. 4 mi 6

N Hummelstown N-4

9. 3 mi 360 N

Union Deposit N-5 12.6 mi 3 N NW-5 13.8 mi 312 NW Harrisburg NW-4 9.6 mi 306 NW Harrisburg NW-3

7. 4 mi 297 kNW New Cumberland NW-2

5. 9 mi 310 NW Highspire NW-1 2.6 mi 303 WNW Harrisburg Airport W-1

1. 3 mi 263 W

Goldsboro W-2 1.3 mi 252 WSW Goldsboro SW-1

2. 2 mi 200 SSW Bashore Island W-3

2. 9 mi 270 W

Unnamed community W-5

7. 4 mi 262 W

Lewisberry W-4 5.9 mi 272 W Lewisberry SW-2 2.6 mi 203 SSW Pleasant Grove 5-1

3. 2 mi 169 5

York Haven 5-2 5.3 mi 178 5 Conewago Hts S-3 9.0 mi 181 S Emigsville SW-3 8.3 mi 225 SW Zions View SW-4 10.4 mi 225 SW Eastmont S-4 12.0 mi 184 5 Woodland View SE-5

7. 0 mi 135 SE Bainbridge SE-4 4.6 mi 137 SE Highway 441 SE-3

2. 3 mi 160 SSE Falmouth SE-2

1. 9 mi 162 SSE Falmouth SE-1

1. 0 mi 151 SSE Unnamed community on Highway 441 E-2

2. 7 mi 110 ESE Unpopulated area E-3 3.9 mi 94 E

N:wville E-4 7.0 mi 94 E Elizabethtown E-la 0.4 mi 90 E Residence S-la 3.35 mi 173 S School (added 4/5/79) SE-4a 5.0 mi 146 SE W-3a 4.4 mi 247 WSW NE-3a

3. 6 mi 44 NE N-la 2.4 mi 356 N

N-lb 2.75 mi 346 NNW N-1c 3.0 mi 0 N N-1d

3. 5 mi 333 NNW N-le 3.5 mi 349 N

119 0,;q-N-1f 4.0 mi 351 N

27 Table 3.12.. PROJECTED 1980 POPULATION DISTRIBUTION, 0-10 MILES THREE MILE ISLAND NUCLEAR STATION, UNIT 2 (FROM FIG. 2.1-5 of SAR) Distance (Miles) Sector 0-1 1-2 2-3 3-4 4-5 5 - 10 0 - 10 N 19 '212 3,970 3,772 41 5 11,840 20,228 NME 55 75 169 480 373 11,223 12,375 NE 42 134 271 428 186 2,246 3,307 ENE 58 55 186 461 262 1,567 2,589 2. 42 60 39 137 552 10,431 11,261 ESE 6 36 149 214 236 2,809 3,450 SE 6 94 67 203 395 2,095 2,P54 SSE 88 197 117 78 43 3,840 4,364 S 0 0 136 81 7 1,317 12,190 14,460 SSW 84 98 584 217 752 6,883 8,610 SW 34 104 1 81 S62 219 4,297 5,447 WSW 29 273 117 796 237 2,961 4,41 3 W 36 369 36 331 571 7,1 b5 8,4rd WNW 22 106 253 197 235 11,823 12,636 NW 39 106 64 41 1,177 29,482 30,909 NNW 48 98 1.240 942 1,921 16,632 20,881 658 2,01_7_ 7,579 9,676 8,891 136,474 ,166,295 / 119 OB .. = . _. =..

28 Table 3.13. EROJECTED 1980 POPULATIO!! DISTRIBUTION,10-30 MILES ( THREE MILE ISLAND NUCLEAR STATIOi!. UNIT 2 \\ (FROM FIG. 2.1-10 of SAR) Distance (Miled Total Sector 10-20 20-30 30-40 40-50 10-50 N 12,663 9,005 8,94i 47,588 78,197 NNE 18,240 6,856 14,478 45,115 84,659 NE 39,726 30,979 9,546 62,345 150,596 ENE 10,205 14,757 45,445 177,672 284,079 E 18,853 62,028 42,445 33,754 162,080 ESE 34,339 124,982 27,822 42,737 229,886 SE 20,152 10,000 10,600 26,958 67,710 SSE 44,204 10,774 15,097 66,763 136,838 S 111,002 14,648 13,477 75,781 214,908 ( SSW 31,917 $4,0 1 18,596 37,729 132,273 SW 11,801 19,931 25,536 18,979 76,247 WSW 5,882 7,996 8,948 23,010 45,836 W 21,769 35,025 10,370 20,602 87,766 WNW 70,460 14,188 5,333 3,681 93,662 Mi 99,593 9,308 9,970 12,630 131,501 tiNW 26,482 10,517 7,256 12,866 57,121 To bi 577,288 433,001 273,860 713,210 1,997,359 ( ~ i19 034 i e

29 Table 3-14. ESTIMATED MAXIMUM DOSE TO AN INDIVIDUAL (Located east or northeast of the site) Cumulative Total dose (mrem) Period (1979) Estimated Dose (mrem) (tonearestmrem; 3/28 - 3/29 45 45 3/29 - 3/31 29 74 3/31 - 4/1 8 82 4/1 - 4/2 0 82 4/2 - 4/3 1 83 4/3 - 4/4 0 83 4/4 - 4/5 1 84 4/5 - 1/6 2 86 4/6 - 4/7 0 86 119 035

30 Table 3-15. ESTIMATED COLLECTIVE 00SE (person-rem) Total Cumulative Period 0-10 10-50 0-50 Total, 0-50 miles 1979 miles miles miles (to nearest 50) 3/28-3/29 206 511 717 700 3/29-3/31 764 524 1288 2000 3/"-4/1 537 315 852 2850 4/1-4/2 44 35 79 2950* 4/2-4/3 109 133 242 3200 4/3-4/4 39 43 82 3250 4/4-4/5 49 82 131 3400 4/5-4/6 41 39 80 3450 4/6-4/7 42 35 77 3550** 1831 1717 3548 In the original assessment, which formed the basis of testimony before the Senate Subcommittee on Health and Scientific Research, this value was estimated to be 1800. xx In updates of the original estimate, which formed the basis for testimony before the Senate Subcommittee on Nuclear Regulation, this value was estimated to be 2,500. 119 036

31 B. Onsite Metrooolitan Edison Dosimetry Data for the ceriod throuch March 31, 1979 Data made available to the Ad Hoc Group on April 12, 1979, indicated that there were some dosimeter readings reported in excess of 100 mrem. These readings greater than 100 mrem are listed below. These dosimeters were on the site or at sites under the licensee's control. The dosimeters with high results on Shelley Island are within the exclusion area of the site. A map showing these dosimeter sites and other Metropolitan Edison dosimeters within 1 mile of the nuclear station is given in Figure 3-2. Dosimeter Desicnation Location Period Dose, mrem TM-16Al 0.4 mi NNW (Kohr Is.)* 9/27/78 3/29/79 908 TM-16A1A 0.4 mi NNW (Kohr Is.)* 9/E//73 3/29/79 453 TM-1452 0.4 mi WNW (Shelley Is)* 9/27/78 - 3/29/79 131 TM-14S2A 0.4 mi WNW (Shelley Is)* 9/27/78 - 3/29/79 156 TM-1651 0.2 mi NNW, West Gate 12/27/78 - 3/25/79 1049 TM-1151 0.1 mi SW, W of Cooling Tower on Dike 12/27/78 - 3/31/79 216 TM-1151A 0.1 mi SW, W of Cooling Tower on Dike 3/29/79 - 3/31/79 107 TM-452A 0.3 mi ENE, Top of Dike East fence 3/29/79 - 3/31/79 124 x Statement. by Teledyne Isotopes Inc., "These gross exposures were obtained in tha absence of designated control dosimeters for.btracting transit ",ses and system background." Since the majority of these dosimeters were onsite they are not considered in the population dose. The dose received by those onsite will be recorded 119 037

, ~~r jf .7.* \\ s j.d E \\ f A ll.<,@ /! \\ M8 f*l 4 .\\ s o q\\'i % .y t'h b 5 g i s s. y k - 's, Q. '. QM ,,s s ti. k p '. 2 p t' \\ ~ i-1 11 ;, a \\A .;p 3. a; i w s. n i \\c t s.,\\\\( ^' ' d.i I 4-tg 21 z 9 4 . t f jl M jD,'. \\, 'e i f ,f :_-591 ji %s t( o .\\ s-k ~~-h 7 i Y% f 3-y 'n

l.N \\,

l R*;j \\ s 3

• [ )

\\y y { i 25' t' i D4 "l Ei .; A a Wi .~l,. {. U9-7 ? '[# kj, '#7 ~ n y as l.M,aQ,. x - llj

.gMf 1 ifs f"I 2

,g2

.w m .~f k'. $ $l Wg )! ( - l ."l; lJ.&W' v (G- +t k li:p o k L .g V _S: y .f $;f.;'f h u 4 i, y; fJ I "o ,{ $ 2 'S O E (*s fi lgQi', ' l }f{ I s' l 6' D j,/. ;, Q, lj,. Ct 2~, / ; i r i c p/ m = us il h. .) CeON j] [ (,, W- ~_ j,.,, i 'l U j/ I-VI / ""3 7 O j., h ~$3* C l / ;'

• Q~'

/ b \\ mV [/ 4ir = W- ^' r* w-wr 4

• f.

"=M U L %Wn 'l s* l '8

• u k Qw st q

c. o m z I

as i */ m (. to, C,) 1 u3c2 ',!n D .! 4 j- /-eT o.,c c e a g g.- N i " l-( fl l,' : y v o,3 m 9 r / 13,[j C - - C3 .&s e e. A, n 'L i f / - '!.+J ' m '.= axmm x, 4 ' yJm A I sf' t' meou l .b o$1N Jl

3. c ; m l

3 - = = ) h I,f % \\') W'~ j ,p y S Qk:q / ? e ~ yu ..g-f ,/v< s l I .= ,i,' >n. >.g / - _. 9 p ~,j u ( - (~, l gM f r,;; _. '_

1. O dd

~ a; j g i; = .= ,.f .Y ).. .. \\ 1; s '. - ~ . a-L

32 in the dosimeters worn by each individual. The two readings from Kohr Island were also not considered for the pcpulation dose since it has been verified that no people were on this site during the accident period. 119 039

33 4. POTENTIAL HEALTH IMPACT A. Health Effects from Low-Level Radiation The health risks from low-level radiation are derived by assuming that the effects observed at high doses from high dose rates can be directly and linearly extrapolated to low doses deliverea at very much lower dose rates and also by assuming that there is no absolutely safe dose (or threshold) below which there is no health risk (linear-non-threshold, dose-rate-independent dose-effect relationship). These assumptions are generally believed to overestimate the health risk from lcw-level ionizing radiation (1-3). There are two different types of health risk estimates used in the 1972 BEIR report, one of which is approximately 2 to 5 times higher than the other. The values used represent the geometric mean (a kind of average) of the two risk estimates. The average was used in an attempt to reconcile the two types of estimates. The resultant somatic health risk factors are shown in Table 4-1. (1) International Commission on Radiological Protection, " Recommendations of the International Commission on Radiological Protection Adopted January 13, 1977" ICRP Publication 26, Pergamon Press, Oxford (1977) Section E pp 6-7. (2) National Council cn Radiation Protection anc Measurements, " Review of the Current State of Radiation Protection Philoscphy." NCRP Report No. 43, NCRP, Washington, D.C. (January 15, 1975) p.4. (3) Advisory Committee on the Biological Effects of Ionizing Radiation (BEIR) "The Effects on Populations of Exposure to Low Levels of Ionizing Radiation," National Academy of Sciences - National Research Council, Washington, D.C. November 1972, Chapter VII, Section IV pp 87-88. 119 0.;0

34 Table 4-1 Estimates of the Somatic Health Risk from Low-Level Ionizing Radiation Effect Health Risk (deaths) per 10 person-rem (") 6 Wange Nominal 1alue Used for " Average"(b) this Analysis Leukemia 25 to 37 31 Other Fatal Cancers:(c) 61 to 429 160 TOTAL FATAL CANCERS 191 200 Thyroid Cancer 100 to 200 cases (d) 140 cases NON-FATAL CANCER 200 8The risk values presented are based upon the BEIR Report (3) or interpretations thereof. bThe " nominal average" risk values presented are based upon linear extrapolations of data obtained at high doses and dose rates to predict somatic effects at low doses and lower dose rates. These values indicate the range of values and were cbtained by applying the absolute risk estimates with a 30 year plateau duration and by applying the relative risk estimates with a lifetime plateau duration for "other fatal cance s." The nominal average values are geometric means of the risk values at the ends of the range (i.e., the square root of the product of the values). cThe number of cases in this category may be twice the number of deaths. "Other fatal cancers" includes lung, GI tract, bone, kidney, and liver plus other sites. The deaths due to these cancer are projected assuming the susceptibility of cancer induction by radiation in persons aged less than 10 years is equa' a that for persons aged 10 years or more. dThyroid cancer risks are treated separately owing to the relatively high survival rate compared to the cancers at other sites considered here. The range of risk values indicated is based on the relative risk model with a 30 year and lifetime plateau duration. The lifetime survival rate for persons treated for thyroid cancer is about 80 to 90 percent. 119 041

35 It is firmly established that ionizing radiation can cause genetic muta-tions, which can be manifested as congenital anomalies (birth defec;s) or hereditary diseases such as hemophilia or Down's syndrome, in descendents of an irradiated par ent or parents. However, the exact numerical value for the risk of genetic injury from low doses is uncertain. 'The genetic effects estimated in 1972 Report of the Advisory Committee on the Biological Effects of Ionizing Radiation 3 are based upon estimates that the radiation dose that would double the natural incidence of genetic anomalies (doubling dose) is between 20 and 200 rem (20,000 and 200,000 mrem). The lower the doubling dose, the greater the risk from a given radiation dose. Table 4-2 summarizes the calculation of the genetic risk from the data given in the 1972 BEIR report. Table 4-3 summarizes the actual health risk estimators used in this analysis. A ? *) (d 's "

36 E O 2 O O O 3 O O O O O .4 m - m Q O L mT .J B C 0 .C O O .J >b .a ou .C 6 U C C L O Q C Q (O CC -= C CJ ^ 3 m m M .C A Q C. U y rc.: o V LaJ +J.s E 6.3 L .3 i' O m *~ Q u 6 C -BA N> l O C % C p-Om m A O

• J

> Q 2a = m r0 O Q". 6 L ag Q O .- O L Q CJ O N 0: V T C. C to -J O M QJ .C Q

J

+J.C .J -C 3

• J tD C

O rg O O .J O C 0 to o +,6 Q 2 E M .J CJ - .J - - C m Q L m C N -2 O +2 L L > = - 3 - m cJ EO Q +J L.J a L' W "U O F3

O m

O C "3 7 Q O CJ X r5 C E 2 E O O O Oh O v = Q C O 6 O m v 3 m 3 O. O C 6 A C L N O Q N fc Q Cc X ^ L f. - m 4 CJ O Q H Q O A % O E Q O ^ 0 L

• J CJ O

+J B * *J E C,. C >b +J U C "a O O - E D O L U C .O - A L C3 Q 0" D Q C O O L J 2 '3 C. L LJ N A m 3 1C 4 -Q ^ Q "O O O N CC

• J O D 2.

E O LL m O v C C m 6 CJ C C 0 Q r3 CJ r3 J L Q O C L 0 X e 0 +J N 3

0. 6 J

c - L L Q O O N e O c L c% U O v -J Av 6 0 O M N +J B SJ C O O mQ m v L CJ +- U C C

• J O

Q O O

== 2 O "3 - O Q

• J Q

O C O m O X CJ .C w 6 O J d i O- "C A .J Q .J. 0 ..U.

• a c

^ >=- +J W 4 m

• J fc 3 0

.) m L U L .J .C "3 ^ "a Q O Q-O 3 CJ + m A L La D L m D Q > 0 Q L .C N c) = .J m W D - CJ - D L .C - O rc J U L O C >

• J

.C 6 "J C. Q Of L Q 4 Q Q N> vA Q B - C Q 3 L CJ OJ Q *- ^ Q 4 O 1Q Q U - c Q o C v .O c v > .-4 Q rg CQ ^ O o oO O o o am N o O L "O O A O O OO O O O + e E O A -e Q 3 .;.a O. O. O. O. O. O. N. .v C M 0 m

• J N Oe A

.J U cO L m o 'J C L L O O DC D O -4 ^ "J r3 0 .J Z = OJ M M -e M M Q m .-O 4 U m X 7 O O v C. - C v r0 E V C. - N O U V J E +J H v J Lm "O '" E X X W O I CJ C W L AN = cc Q Q N CJ Q O E L e4 A

• J A

CY. m ^ O I .C C r3 O

• ) % A A

C O .J Q m CE - O Q A O 6 A B mB B v3 A ll

• J Q

QV "" A O Q LaJ C C-L 4 7 m =~ Q 03.J C 3 m Q ^ U m r3 - A C-1 a Q Q CJ Q M B 'C D O NOJ += m "O e E Q Q N = r3.C C ts 1 r3 C-O L - Q 1 O-- O O O O - A Q r; '3 C C. PC >

• D 3-

'- ~ Q A B C3 X C Q Q L.C ~J LQ 1 - CJ Q C.J O Q U Cv 1 L O 7 1 > "3 -J e* .= Q 1 L

• J O)

M U E-t A .J L .J L E O O O N .J O A .J Q = 0 6 a rc 0; C M W Q C B A ad C O Q E 6 0 .:4 0 A r5 0 Q C- - 0 O O Q L O A X A ~3 C EU Q c'3 .J Q L. .O O r3 Q 0 OJ QE A Q 4 LA. -N < % N U A E L L C O C '; W ^ ^ ^ ^ O O C O M .C U 'C O O U U< U 0" w v v v 119 07.3

37 Table 4-3 Summary of Health Risk Estimates Used in This Analysis Risk per Effects per 0 rem 10 person-rem C ~4 Fatal Cancers 2 x 10 200 ~4 Non-Fatal Cancers 2 x 10 200 -4 Genetic Effects 1.8 x 10 180 TOT.". F0TENTIAL ~4 HEALTH EFFECTS 5.3 x 10 580 119 041

38 8. Comoarison of Doses to Individuals from the TMI Accident with Natural Background Radiation and its Variability Man is continually exposed to ionizing radiation which occurs naturally. There are three primary sources of this natural radiation " background": (1) solar and galactic cosmic radiation, (2) long-lived radionuclides in the earth's crust (primordial radionuclides) and (3) radionuclides formed in the upper atmosphere from the interactions of the cosmic radiation with gases in the atmosphere (cosmogenic radionuclides). The magnitude and variation in the radiation dose from these natural radiation sources provides one baseline for comparing the doses and the potential health impact from the Three Mile Island accident. Estimates of the dose from background radiation at several 1ccations in the United States are shown in Table 4-4. None of these values are measured values but they are generally consistent with reported measurements.( ) Table 4-5 compares the estimated individual doses from the Three Mile Island accident to some of the variations in annual radiation doses frcm background radiation. It should be noted, however, that the " background" doses are delivered over 1 year whereas the accident doses were delivered over only a (4)D.T. OaKley, " Natural Radiation Exposure in the United States," EPA Report ORP/SID 72-1, U.S. Environmental Protection Agency, Washington, D.C. (1972). (5) National Council on Radiation Protection and Meaeurements, " Natural Back-ground Radiation in the United States" NCRP Report No. 45, NCRP, Washington, D.C., November 15, 1975. ) ) 0 0 ~)

39 few days. The possible significance of this higher dose rate is discussed in a following section on dose-rate effects. It shculd also be noted that the " average" doses to individuals within 10 and within 50 miles of the site are numerical averages obtained by dividing the collective population doses by the size of enclosed population. Clearly, some individuals received more than this dose and others less, depending upon wind direction and distance from the TMI site. \\\\9 on6

40 Table 4-4 Estimates of Natural " Background" Radiation Levels in the United States Annual Dose Rate (mrem / year) Location Cosmic Terrestrial Internal Total Radiation (a) Radiation (a) Raciation(b) Atlanta, Georgia 11.7 57.2 28 130 Denver, Colorado 74.9 89.7 28 193 HARRISBURG, PA. 42.0 45.6 28 116* Las Vegas, Nev. 49.6 19.9 28 98 New York, NY 41.0(c) 45.6(c) 28 115 PENNSYLVANIA 42.6 36.2 28 107 Washington, DC 41.3 35.4 28 105 UNITED STATES 40-160 0-120 28 70-310 (a)From [(4) Table A-1] ( ) Based upon total of internal (gonadal) doses from [(5) Tables 42 and 43, p. 104]. (c)From [(4) Table A-2] A Earlier estimates used an approximate value of 125 mrem / year based upon the Final Environmental Statement for the Three Mile Island Facility (AEC, 1972, Section VD 7, p. V-28). As neither values represents direct measure-ments and ambient radiatioit dose rates are expected to vary by at least 25% between locations within a 50-r?le radius, these estimates are essentially identical. 119 047

41 ~ Table 4-5 Camparison of Individual Doses from the Three Mile Island Accident With Variations in Natural Backgrounc Radiation Ocses Source of Radiation Exposure CUMULATIVE THREE MILE ISLAND TOTAL BODY DOSES ACCIDENT DELIVERED THRU 4/7/79 Individual remaining out-of-doors at location of highest estimated offsite dose 86 mrem Average dose to a typical individual within: 50 miles of site 1.6 mren 10 miles of the site 11 mrem ESTIMATED DIFFERENCE IN NATURAL BACKGROUND VARIATION ANNUAL DOSES Living in Denver, Colorado compared to Harrisburg, PA + 80 mrem /yr (from Table 4-4) Living in a brick house instead of a frame house [Yeates data in (4) Tacle 16, p. 35] + 14 mrem /yr Added dose from potassium-40 due to being male instead of fecale 4.8 mrem /yr + (There is 25% less potassium in women than men [(5), p. 106]) i 19 0 >"> 3

42 C. Ccmoarison of the Potential Health Imoact Estimated for the TMI Accident with Existina Cancer Rates and Risks Cancer is the seand leading cause of death (next to heart disease) in t'e United States [(6) p. 14)]. The Vital Statistics of the United States, h 1976* shows that there were 377,312 deaths in the U.S. from cancer, which corresponds to a rate of 175.8* cancer deaths per 100,000 people [(6) p. 14]. Cancer deaths accounted for approximately one-fifth (0.198) of all deaths in the U.S. 11 1976. The existing cancer rate provi6s an indication of the possibility of detecting any potential increase in cancer incidence. The cancer death rate for the State of Pennsylvania estimated by The American Cancer Society [(6) p.12) is 208 per 100,000 (2.08 x 10-3), Maryland has a icwer estimated rate (179 per 100,000) which is closer to the estimated U.S. rate of 180 per 100,000 [(6) p. 12]. Applying these values to the 2,165,651 people estimated to reside within 50 miles of the Three Mile Island site gives an estimate of 3,900 (U.S.) to 4,500 (Pa) deaths per year for the existing cancer death rate for the population within 50 miles of the TMI site. Table 4-6 shows the estimated incidence (number of new cases) and death rate for the U.S. population for selected types of cancers. "Our earlier estimates used 1974 statistics and a U.S. cancer death rate of 170.5 per 100,000. (6)From American Cancer Society, " Cancer Facts and Figures-1979," Reprcduced by permission of the American Cancer Society who retains copyright. Sub-sequent quotations should ackncwledge the American Cancer Society as the source of these values. 119 049

43 Table 4-6 Estimated New Cancer Cases and Deaths in the United States for 1979 (Existing Rates) Cancer Site Estimz.ced* Estimated

• Deaths / Cases (a)

New Cases Deaths Digestive Organs 182,900 105,150 0.57 Lung 112,000 97,500 0.87 Bone 1,900 1,750 0.92 Skin (D) (excluding melanomas) 300,000 1,600 0.005 Breast 106,900 34,500 0.32 Genital Organs 143,500 44,800 0.31 Leukemia 21,500 15,400 0.72 Thyroid 9,000 1,000 0.11 All Sites 765,000 395,000 0.52 (8)If cancer rates and the population (and its age composition) were constant this ratio would be a measure of the probability of dying from having specified types of cancer. As neither existing cancer rates nor tne U.S. population and its age breakdown are constant, this is only an approximate measure of severity of cancers at a particular site. ( Melanoma is a skin cancer which has not generally been found to result from radiation exposure. For this reason, melancma data has been excluded, although it is the predcminant form of skin cancer and has a high mortality rate. x From American Cancer Scciety, "rancer Facts and Figures-1979" p. 10. Repro-duced by permission of the copyright holder, the American Cancer Society. All subsequent quotations of these values should acknowledge the American Cancer Society as the source of these estimates. 119 000

44 The American Cancer Society [(6) p. 14] estimates that, out of 100,000 people, 25,000 will eventually develop cancer and, of these 25,000, about 15,000 will eventually die of cance. This gives an estimate of the risk of cancer death of 0.15.* Applying this approximate statistic to the 2,165,651 people witMn 50 miles of the Three Mile Island site indicates that approximately 325,000 people in that area would normally die of cancer. n An earlier estimate of 0.12 was obtained by multiplying the 1974 annual death -3 rate of 1.7 x 10 by 70 years. 119 051

45 D. Summary of the Health Imoact Table 4.7 shows the estimated potential health effects from the Three Mile Island Nuclear Accident associated with the estimated 3,550 person-rem delivered to the population within 50 miles of the reactor. These estimates consider fatal cancers, non-fatal cancers and genetic ill-health to all future generations. The total number of future fatal cancers is less than 1 (0.7). The additional number of non-fatal cancers is the same. The total estimated health impact of the accident (through April 7,1979) to the population residing within 50 miles is 2 additional ill-health effects. This value and tnose for the cancers are small compared to either the existing annual incidence of similar effects or the potential effects estimated to result from the natural background radiation. Comparing the total potential health impact of the accident with the estimated life-time natural risk indicates that these effects, if they occur, would oe undetectable. The added 'ifetime risk of fatal cancer to the hypothetical maximum exposed individual from tne accident is 1.9 x 10-5 (0.000019). This is based upon a presumed 100 mrem dose rather than the calculated 86 mrem value. This is extremely small (0.013%) compared to the normal risk (0.15) to an individual of dying from cancer. It is also small (1.1 percent) compared to the potential lifetime fatal cancer risk that would be associated with natural background radiation using the same dose-to-health effect relationships as used for the accident impact. 119 052

Table 4-i' Projected Potential llealth Impact of tha Three Mile Is!and Accident Upon the Population within 50 miles (a) Annual Rates Cumulative llealth Risk Estimated Potential Estimated Potent.ial Impact. of~ Potential Impact of from Existing Impact of Number who will Natural Backgrocad THI Accident Rates (b) Natural eventually Radiation (d) thru 4/7/79

Background

develop effect (% os normal (% of normal incidence) Radiation (c) incidence) fatal Cancers 3,900 54 per year 325,000 3,790 (1.2%) 0.7 (2.2 x 10~4 ) ~4 ) Non-Fatal Cancers 4,900 54 per year 216,600 3,790 (1.8%) 0.7 (3.2 x 10 Genetic Effects 2,600(") 49 per year ") 78,000 1,460 (1.9%)(I) 0.64 (8.2 x 10~4 ) f II) Total llealth Impact 2.0 Effects ( )2,165,650 projected for 1980. (b) Based upon U.S. statistics. I" A 0.125 rem per year (125 mrem / year); approximately 2/0,700 person-rem. (d)70 year cuniulative exposure. (")f_ nom BEIR 1972 estimates given in Table 4.2 of 1,200 per 10 eople. 6 (# sed upon a 30 year reproductive period. O C1 L-4

47 E. Dose-Rate Effects The estimated dose to a hypothetical individual (85 mrem) is numerically approximately the same as the annual dose from natural background radiation to residents in the'Harrisburg area (115-125 mrem /yr). There has been some concern that, because this dose was delivered in 1 week instead of 1 year, the biciogical effects of this accident would be greater than from natural tickground radiation. This reasoning presumes a " dose-eate" effe -' rather than the linear dose-rate-independent dose-effect model. If there were such a " dose-rate effect," then the health consequences of the accident would be overestimated and not underestimated. This is becaust the estimates of the health effects of low-level radiation are derived from observations made at much higher doses and dose rates than experienced during the Three Mile Island Accident. Existing estimates indicate that somatic effects (cancer) might be over-estimated at low doses by a factor of 2 to 4 (7, 8) and perhaps as much as a factor of 10 (8) and that genetic effects might be overestimated by a factor of 3 (8). Tha estimates of the health impact of the Three Mile Island Accident have not included any reduction factor to account for do"-rate effects. (7) United Nations Scientific Committee on The Effects of Atomic Radiation, " Sources and Effects of Ionizing Radiation - 1977 Report", UNSCEAR, United Nations, N.Y., N.Y. (1977), Annex G, p. 366, paragraph 36. (8)NCRP Scientific Committee 40, " Influence of Dose and its Distribution in Time on Dose-Effect Relationships for Low-LET Radiation" Draft of February 21, 1979, page 3. \\\\0 0

48 5. OTHER SOURCES OF EXPOSURE A. Skin Doses and Health Risks fren Beta jnd Gamma Radiation from Xenon-133 The contribution of beta particles from xenon-133_is not addressed by wither the dose analysis in Section 3 or the health impact analysis in Section 4. While the beta dose cannot be assessed by direct measurement during the accident, it can be estimated from the literature. The depth dose from xenon-133 electrons and beta particles decreases by a factor of 0.39 at an areal density in tissue of 0.005 g/cm2 (or a depth of 0.005 cm or 50 pm). This depth was se.lected to approximate the thickness of the " dead layer" of skin.(1-2) The depth dose to blood forming organs from beta particles is essentially zero. The beta particle skin dose at the 50 pm depth, estimated from the depth dose calcula-8 3 tions of Berger(3) is 4.7 x 10 mrem /yr per pCi/cm com ared to ORNL [ David Kocher, ORNL, personal ccmmunication to C.B. Nelson] estimates of the xenon-133 8 3 gamma-ray total body dose of 1.90 x 10 mrem /yr per pCi/cm, or a factor of 8 2.47 higher. The gamma-ray skin dose is 2.55 x 10 mrem /yr per pCi/cd Therefore, (1)"Recommer.dations of the International Commission or. Radiological Protec-tion Adopted January 27, 1977," ICRP Publication 26. Pergamon Press, Oxford, England, paragraphs (63) and (64), p. 13. (2) National Council on Radiation Protection and Measurements, " Krypton-85 in the Atmosphere - Accumulation, Biological Significance, and Control Technclogy," NCRP Repcrt No. 44, National Council on Radiation Protection ano Measurements, Wasaington, D.C., July 1, 1979. Table 13, p. 30. (3)M.J. Berger, " Beta-ray dose in tissue-equivalent material immersed in a radioactive cloud," Health Physics, vol. 26 (1): 1-12 (January 1974). ) ) } YJ J

49 8 3 the combined beta and gamma " skin" dose is 7.25 x 10 mrem /yr per pCi/cm, or a factor of 3.8 times the total body gamma-ray dose. The TLD readings were assumed to be equivalent to the total body gamma-ray dose. For the.aaximum exposed individual, the beta skin dose would be about 325 mrem. The 1972 report of the National Academy of Sciences' Advisory Committee on the Biological Effects of Ionizing Radiation (4) does not provide numerical estimates of the risk at low doses for skin cancers. Skin cancers from radia-tion exposure reported in this report are associated with doses above 230,000 mrem in rats and above 450,000 mrem in humans This latter dose is sufficient to cause visible e.ffects on the skin and is more than a factor of 1,000 greater than the estimated total (beta and gamma) skin dose to any exposed individual, even neglecting shielding by clothing or by being int ors. The International Commission on Raufological Protection considers skin to be less liable to develop fatal cancers after irradiation than other tissues (1). They recommend a lifetime occupational dose limit for skin of 2,000,000 mrem (1) or 5,000 mrem per year for members of the general public (Reference (1) p. 25). It is also significant that the ICRP has considered the organ at the highest risk (critical organ) for exposure to radioactive noble gases such as xenon-133 to be the total body and not the skin or lung (5).

5) Advisory Committee on the Biological Effects of Ionizt 3 Radiation (BEI1),

"The Effects on Populations of Exposure to Low-Levels of Ionizing Radiation", National Academy of Sciences - National Research Council (1972) pp 132-135. (5)" Recommendations of the International Commission on Radiological Protection. Report of Committee II on Permissible Dese for Internal Radiation," IC.P Publication 2, Pergamon Fress, Oxford, England, 1959. \\\\9 056

50 The 1977 report of the United Nations Scientific Ccemittee on the Effects of Atomic Radiation (6) provides estimates of the risk of skin cancer from -6 exposure to high doses. Neglecting two lower values of approximately 4 x 10 the 50 year lifetime average risk from these data is estimated to be approxi-d -5 mately 1.9 x 10 If the entire population within 50 miles of the TMI site were exposed out-of-doors and withoat clothing for the entire duration of the accident, the total number of projected health effects (fatal and non-fatal cancers, and genetic defects to all future generations) could increase by about 12 percent (from 2.0 to abcut 2.2) due to all the skin cancers that might occur in the next 70 years. Only about 6 percent. [ Reference (6) Annex G Table 1, p. 363] of these skin cancers would be fatal, so the overall increase in cancer fatalities might be about 2 percent from 0.71 to 0.72. Thus, the health impact of dose to the skin from beta and gamma radiation is a very small fraction of that estimated for external gamma ray exposure of the total body. ^ This is actually a lifetime (70 year) risk since the assumed latent period between radiation exposure and the onset of cancer is 20 years. Reported mean latent periods for skin cancer are 24.5 and 41.5 years (6) Table 1,

p. 363].

(6) United Nations Scientific Committee on the Effects of Atomic Radiation, UNSCEAR, " Sources and Effects of Ionizing Radiation," 1977 Report, United Nations, N.Y. (1977) Annex G, Radiation Carcinrgenesis in Man. Section H., pp. 411-412. 9 057

51 8. Inhalation Lung Dose and Risk of Lung Cancer The gamma total body dose frca xenon-133 is given in NRC Regulatory ~4 3 Guide 1.109(7) Table B.1 as 2.94 x 10 mrem / year per pCi/m. The xenon-133 -9 inhalation dose factor (8) is 1.57 x 10 mrem per pCi inhaled. Multiplying this latter value by the annual volume inhaled per year (for an adult) of 3 3 -5 7.3 x 10 m / year gives an equivalent dose factor of 1.15 x 10 mrem / year 3 per pCi/m. This value is ppproximately 4 percent, (0.039), of the external whole body dose factor for an equivalent air concentration of xenon-133. The lifetime lung cancer risk (from Table 4-1) is 0.4 x 10'4 per rem or about on -fifth (0.2) of the risk of fatal cancer from total body irradiation. Combining this with the above estimate of the relative lung-to-total-body dose of 0.039 yields an estimate for the risk of lung cancer due to xenon-133 inhalation of (0.039) (0.2) = 0.0078 or 0.8 percent of the total fatal cancer risk from external gamma irradiation from xenon-133. This is a small increase in risk compared with the other uncertainties in the calculation of health risk. (7)U.S. Nuclear Regulatory Commission, Regulatory Guide 1.109, Revision 1, " Calculation of Annual Doses to Man from Routine Reactor Effluents for the Purpose of Evaluating Compliance with 10 CFR Part 50, Appendix I," Octcber 1977. (8)G.R. Hones and J.K. Soldat, " Age-Specific Radiation Dose Commitment Factors for a One year Chronic Intake" U.S. Nuclear Regulatory Commission Report NUREG-0172 (November 1977), Table 8, p. 38. 119 CSS

52 C. Airborne Radioiodine Concentrations and Doses Metropolitan Edison placed charcoal cannister sampling systems in the environment to measure the concentration of radiciodine in air. The NRC Of fice of Inspection and Enforcement (I&E), as part of their mnnitoring program, obtained air samples at " Trailer City" to measure the radiciodine air concentration. The result obtained from these measurements are given below. Location Period Concentrations Observation Tower 3/29/79 - 3/31/79 20 pCi/m3 2.3 mile SSE (2 x l0'11 pCi/cm ) 3 (Met. Ed) Observation Tower 3/31/79 - 4/3/79 1.4 pCi/m3 (Met. Ed) (1.4 x 10 12 pCi/cm ) a Trailer City 4/1/79 - 4/4/79 <9 x 10 13 pCi/cm 3 NRC Trailer City 4/5/79 1.6 x 10 12 pCi/cm3 NRC The measured radiciodine concentrations in air have been used to estimate maximum dose to a child's (receptor) thyroid using the inhalation dose factor in reference (7), p. 29. 9 059

53 Dose (mrem) First three day period 3/29/79 - 3/31/79 conceatration 2.3 mi SSE 2.7 Second three day period 3/31/79 - 4/3/79 0.19 NRC data assume 2 x 10 12 pCi/cm3 for period 4/2/79-4/3/79 (some overlap with record three-day period) 0.18 3.1 0. Thyroid Dose from Ingestion of Iodine-131 in Milk A large number of milk samples were collected during the period March 28 through April 4, 1979 from farms and dairies throughout the area surrounding the accident site by the Pennsylvania Department of Environmental Resources, the Food and Drug Administration and Metropolitan Edison. Aliquots of several of these were also analyzed by the Environmental Protection Agency. A summary of the results is given below: Metropolitan Pennsylvania FDA EPA Edison Number of analyses performed 133 84 4 21 Number of positive results 7 53 2 18 Average value of positive results (pCi/2) 15 19 17 7 Range of positive results (pCi/2) 11-20 9-41 10-24 1-41 Average minimum detectable activity (pCi/2) <20 <10 <10 <1 \\\\9 360

54 Additional milk samples collected since April 4 have been negative. This indicates that any iodine-131 ingested through milk consumption occurred during a period of a few days and can be treated as a single deposition event. Using the highest concentration of iodine-131 observed in'any single sample of milk as the worst case, 41 pCi/t in goats milk, the dose to the thyroid of an infant drinking 1 liter of milk from that source for the entire duration of the accident would be 5 mrem over the lifetime of the individual. This is derived from the protective action guide that relates 12,000 pCi/l to a 1.5 rem dose to the thyroid. Under these conditions, an adult drinking the same milk would receive a lifetime thyroid dose of 0.5 mrem, based on a thyroid weight 10 times greater than the infcnt (20 g versus 2 g). Cesium-137 was also detected in some of the milk samples at levels generally less than 25 pCi/ liter. The maximum reported level was 37 pCi/ liter. The presence of this radionuclide is probably due to deposition of residual fallout produced from previous atmospheric testing. Review of results from pasteurized milk samples analyzed for the previous year from Pittsburgh and Philadelphia by EPA show the presence of cesium-137 also for several samples during that period. The levels were less than 12 pCi/J. The Pittsburgh and Philadelphia samples represent milk samples composited from more than one source; the samples collected during the Three Mile Island incident represent specific farms and dairies. 119 06i

APPENDIX A Department of Energy (00E) Estimate of External Whole Body Radiation Exposure to Population Around the Three Mile Island (TMI) Nuclear Power Station. The DOE assessment of the external whole body radiation exposure to the population around the Three Mile Island (TMI) nuclear power station was based on over 125 measurements of radiation taken on March 28, 1979 through April 3, 1979, in the center of the plume of airborne discharges. These measurements were taken from helicopters, using Geiger-Mueller survey instruments with probes having open, low density windows, to enable measurements of the gamma radiz. tion exposure, plus any contribution from high energy beta radiation. The radiation survey probe was held external to the helicopter (s) to minimize attenuatio1 of any radiation. The measurements were made at various distances out to ten miles from the TMI plant. At each distance, the helicopter (s) were maneuvered to find the maximum radiation exposure rate, and this maximum value was used in the calculation of population dose within any sector. The geographical region within a 50-mile radius of the plant was plotted out in concentric and azimuthal sectors, and the population exposure within each sector was calculated based on (a) the measured radiation dose rates, \\\\9 D62

A-2 (b) records of the helicopter location for each measurement, (c) the path of the plume, and the duration of its passage, as well as predictions of its course and speed from curn '. meteorological data, and (d) population figures for each sector projected for the 1980 census. Also assumed was (e) a factor of two reduction'in radiation dose to an individual at ground level due to instrument geometry and (f) that members of the population were out of doors during the entire duration of passage of the plume. Figures A-1 and A-2 show exposure profiles for the 0-2 mile and the 0-10 mile radii, respectively, for the average exposure to individuals on the ground. The exposure rates at distances beyond ten miles from the plant were extrapolated from a curve drawn through the exposure measurements measured as a function of distance within ten miles of the plant. The cumulative population dose to external radiation within the 50-mile radius using the above data and assumptions was approximately 1700 person-rem ! 425 person-rem through April 3, 1979. Table A-1 provides the contributions to the total cumulative pcpulation dose from each of the population sectors. The maximum estimated dose to any person was 95 mrem to a hypothetical indi-vidual located three-tenths of a mile east of the station for the entire week following the TMI occurrence. The average estimated dose to the 2,165,651 persons within the area considered would be less than 1 mrem, or about 1% of the yearly exposure due to natural radiation. 119 06';

l ~ \\ ,/ ,/ 1 l/k ) 7%. 0 [ 4 f i.i fgar ,gg Pb _cg,, + ~ _ Th!. $f]"^ '^' }y '&f ,.3 g u ~., I l

• )

~-' i ' #(*. /- k g/. ~ , -{s= ~, i Q% sa 3A\\. ,1 1' Qw,:- i \\ \\ '\\ e.' -,,, k 4 e 7 , ' '] ~ aa m nr' s g) g /

h. 8',

.4 - JD ETA. REF. t' '.ficua E 2.3 '

j. P

'u '+s, w n,. ,) / l ,s ~ ., l y,s ' \\ pgc 'm o Taa:: wt 15'.ao - >> g-- Q y 'i,g; s } f g'7 :i s .g. . - n a Po r, STATE, 'I i ), <. l} ! 4W / / // %w.'d S 's. ' " ,l Sl N Q 't gh 2 &~ }, - f g.. ' ' ;,q' *3 ,.~& 3, I .f,"- M ~~ j)]* 3 \\' h~ r' s,fL ?!3 \\* W 4 js ih .c \\ ,A q , L. -]\\ g7S - l 'k. -b Y kl',<,h'),.yd (D ~, '\\ \\ \\; 'i' ,L & ' (r\\ 'z x \\

)(.~_W '- _,,,,C, }

s 4 v r [/ \\ ',l-[,.-(g/' [ 'Y!.[. 'I' /,% &,\\ -=J a Figure A-l. 00E 2-mile Expo _ k f',. \\ sure Profile (mR) O TOPO US for the period .. - i?.25 MILE ISL ' D ~ March 28 - April 3, k.2: t.::k.40 st a0Uh 4 1979-3d 1'#'S"A GEbdR% S/ .M._ A LI2 (: % i<

09',- ~ iC fl I'./ '., I' #' 9 \\ ~ t-- M r- .C().l,w-. ..,f., f, fi P8 % tO G 5 0 G \\ S Q' \\,l) e p D a. p '

• h ~*"* -- b,1 -, --

0 7(jorrniets- ~ ' i-) Q ",. .., ',. ',gtrg',__-df'/':=3{htih Y . g' i h ~'N.'._ \\ t... ~' 33 4 0: W ..' s. .;;4 c y _s ,,. s,,,_) i-%[h *~' 5gM ]55 "b.J.(;' c- ~ J e fh;. / d-I !*lIll. % f. p/ --- '., f' - ,4.4fD. N l '? e e %/ '.. ~, -,, y, p '-' q.m s 1 s. t,0;sOrGO.,,. ' /1 <. - sih p.y 3 n ,23 '= ' '- (c. i s._^ . = :+ O Q.

t y%'

(7 i b .G 3h p - s.,;;,. -s. 'i ne; -

n.t.

. ~4sp\\,e.. .. @q .c ,,cm -s ,a1 3 r_ %t \\ x- \\,. m,, .. -) ** ,2 U.. j/ M. c s 3 ys Q;df 4 ,.7, -O',A/. j u .s. t ~ 4 S C1 fiP.c g2 s s \\ A u 38 ,e ;y i o 4 \\ _p e 71 C,w. ',_. N1, % MJ# ' l 'l d/ -... c ( 'E ,mem,. erry 3 j- .s ._s. .;v.. j y\\ (/ s, /.,.. g \\ r,. . a c r' s s v .,:.,~., - crin ul StriN . f/ \\. q'. -. ko,.. t. 77 - - a n o$o,' l ~ ~ > i;- 0-('

r,

/y / INCH 0r;- /... .\\ ,5. a, ijja -Ql e7' 'l' m,_ p,I 2'.v '>'S \\ j y e ' _,, -- 3-,, y o.- c. r- "'/ C / Wcils '\\M t. 9oyal E' M "' M@ Q / ..-Gy l villa (74 s,- , 3 a;;...' /x _..... v.. s,c.,c, ;,. . ., ~.,. ., o ..s 2OWTl ' N 3 .,-s-Dover N ISOIS-2 i town /- . s <-- rm\\ 'o Yf j m$@u C-

1. D

. (750i. 'c a ' ~ u'~u /g <3 .L / ~ ,jd ,Q Aclmiro cf iM,. ~ Qc:'...- .7 W., s s 3,. O! STANCE I TOTA!. I C'J11. TOTAL. 0-1 '11. 553 1-2 'A I.

2. 017 2.575 Figure A-2.

COE 10-mile Ex::osure Profile (mR) 2-3 T;I. 7,573 10,254 for the period March 28 - April 3, 3-4 ': 1. 9,573 IS,S20 I979-119 065,- 4-5 'J l. 8,891 25,321 5-10 '1. 137,474 4 %,235 - Y ~-- 165 h,,,, icm 25 f.Y"2 k sm.usics aAaius r 2

A-3 This assessment overestimates the actual exposure because of the following conservative assumptions: (a) No reduction of the radiation exposure was made for shielding of individuals during periods they would be inside. (b) Some of the helicopter flights and radiation dose measurements were made in response to known increases in discharges from the plant. iherefore, they would be higher than average values. (c) The maximum doses measured in the plume were applied to the entire sector affected. Table A-1. Collective Dose to Population 0-50 miles from Three Mile Island Nuclear Station March 28 through April 3, 1979 Department of Energy Aerial Radiation Survey Radius around Average Estimated Total Total Nuclear Station (miles) Excosure (mrem) Pooulation Person-rem 0-1 45 658 29 1-2 38 2,017 77 2-3 27 7,579 208 3-4 18 9,676 175 4-5 15 8,891 133 5-10 5.7 137,474 781 10-20 0.45* 577,288 258 20-30 0.033* 433,001 14 30-40 0.0023* 273,857 0.6 40-50 0.00015* 713,210 0.1 TOTAL 0.77 2,165,651 1,677 425

• Extrapolated doses (see text)

NOTE: Estimated maximum exposure to a hypothetical person, 0.5 mile east of plant, remaining under the plume for 43 hours, is 95 : 25 mrem. 119 066

APPENDIX 8 DOE Environmental Deposition Measurements in the Area Surrounding the Three Mile Island Nuclear Power Station Following the accident at tr'e Three Mile Island Nuclear Stations, the DOE established the following environmental monitoring activities starting as of 4:00 p.m. on March 28, at the request of the Commonwealth of Pennsylvania, in accordance witht the DOE Radiological Emergency Assistance Program: (a) Helicopter surveys to locate and measure gamma and beta radiation in the airborne discharges. (b) Ground vehicle radiation surveys in the path of airborne discharges, including some in situ radionuclide identification by gamma spectrum analysis. (c) Collection of environmental soil, grass, surface water, and air samples in the path taken by airborne discharges. (d) Gamma spectrum analyses of these environmental samples to detect, identify and quantify any radionuclides present. 119 067

B-2 (e) Evaluation and interpretation of survey and analytical data to estimate population exposure. DOE established three field laboratories for analyzing samples of soil, surface water, grass, and air for gamma-emitting radionuclides. These labora-tories were located at the Capitol City Airport. Each utilized a sensitive, high efficiency lithium drifted germaniun; detector and multi-channel gamma spectrum analyzer. One set of each was brought in and manned by radiochemists from the Brookhaven Natior.al Laboratory, Bettis Atomic Power Laboratory, and Knolls Atomic Power Laboratory. Environmental samples were collected by crews frcm these laboratories, with specific attention to locations near the plant, and to areas over which the plume of discharges from the plart had pers:sted, and was known to have touched down. Attention was also given to assuring that the sampling method would establish if any radioactivity from the plume had been deposited on the ground. The soil, grass and water specimens were skimmed from the largest surface areas practicable to fill Marinelli geometry containers in order to optimize the sensitivity of the analyses, and thereby incraase the likelihood of detection. The air samples were taken both by Silver treated silica gel samplers flown into the plume to ensure capture of any non-ionic radioiadine present. Charcoal filters were used in ground sampling larger volumes of air in the plume. The total number of samples collected and analyzed starting on March 29 has been in excess if 800. The detection sensitivity achieved (minimun 119 063

B-3 2 detectable activity (MDA)) for iodint:-131 was at least one nCi/m for soil -7 -11 and grass, 1 x 10 Ci/ml for water, and 7 x 10 Ci/ml for air. Even lower MDA's were achieved on many samples by longer counting periods, by further idealizing of geometry, and when background radiation was lower. These measures 2 2 enabled sensitivities as low as 0.3 nC1/m for soil, 0.02 nCi/m for grass, 4.0 x 10'O pCi/ml for water, and 2.7 x 10 pCi/ml for air. The gamma spectrum -12 measured for each sample was examined in its entirety to detect any photopeaks. The detection sensitivity of this equipment was sufficient to reveal any uranium in the air in the range of allowable occupational concentrations, if any had been present. The analyses of these environmental samples revealed the presence of iodine-131 in only a few air and grass samples, at b r ely over the detection limit, when che greater sensitivities were achieved. In a few soil samples, cesium-137 radioactivity was detected as expected at levels normally found due to world-wide fallout from previous atmospheric testing. The Silver treated silica gel air samplers which had been flown through the plume, and the charcoal air sample filters used for the high volume ground level samples in the path of the plume, were returned to Brookhaven National Laboratory for further analysis to detect the presence of beta, or alpha emitters by other techniques. Hcwever, such species are considered entirely unlikely since the properties of the chemical species in which such radio-nuclides exist are known to promote retentien within the reactor fuel and/or 119 n/Cuul

4 B-4 coolant. Containment air samples analyzed on March 30 did not reveal the presence of any such nuclides. Direct in-situ measurements of radioactivity on the ground were 1so made by the DOE Environmental Monitoring Laboratory (EML) using two large volume, pressurized ionization chambers, and a very sensitive, high efficiency Lithium drifted Germanium detector gamma spectrometer. Thus a systems enable detection of variations in radiation levels from natural or man-made radioactivity of a fraction of a microrcentgen per hour. These vehicle mounted systems were deliberately moved to locations where those few environmental grass samples were taken which, when analyzed in the laboratory indicated iodine-131 at concentrations just above the MDA. These EML measurements cc,nfirmed both the concentrations measured in the laboratory, and the identification of the specific radionuclide iodine-131. Other measurements by the EML systems also confirmed the generally negative results found in the laboratory analyses of the environmental soil, water and grass samples. The date, time and specific location of all of the environmental samples, as well as the results of the laboratory analyses are recorded in the Technical Work Record books of the DOE team. The results of these analyses of the environmental samples, as well as ganma spectrum analyses of the plume made by the EML mobile system, support the conclusion that the predominant radionuclide in the airborne discharges 119 070

B-5 was the inert gas xenon-133, with a small amount of iodine-131 also present. This conclusion is supported by information received from the NRC licensee (Metropolitan Edison) concerning the measured composition of stack discharges, and the analyses of the air radioactivity in the containment. r [7 i I}}