ML20080R110

Affidavit of DD Ed,Clarifying Testimony Re EPA Rept, Protective Action Evaluation Part Ii,Evacuation & Sheltering as Protective Actions Against Nuclear Accidents Involving Gaseous Releases

ML20080R110
Person / Time
Site:	Byron
Issue date:	10/10/1983
From:	Ed D COMMONWEALTH EDISON CO., ILLINOIS, STATE OF
To:
Shared Package
ML20080R087	List: ML20080R084 ML20080R110
References
ISSUANCES-OL, NUDOCS 8310170356
Download: ML20080R110 (119)

Text

{{#Wiki_filter:. UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION BEFORE THE ATOMIC SAFETY AND LICENSING BOARD In the Matter of ) ) COMMONWEALTH EDISON COMPANY ) Docket Nos. 50-454 OL ) 50-455 OL (Byron Nuclear Power Station, ) Units 1 & 2) ) AFFIDAVIT OF DAVID D. ED I, David D. Ed, being duly sworn, hereby state as follows: I provided written direct testimony before the Licensing Board in the above captioned proceeding. A portion of that testimony reads as follows: The factors for dose committment reduction afforded by sheltering are derived from the EPA report entitled " Protective Action Evaluation Part II, Evacuation and Sheltering as Protective Actions Against Nuclear Accidents Involving Gaseous Releases" (EPA 520/1-78-001B). If the predominant type of structure is unknown or of a mixed type, the dose reduction factor used for sheltering is a conservative value assuming a single-story wcod frame building, the least protective type of sheltering provided by a permanent structure. As it was brought to my attention by the Memorandum Regarding Official Notice of the Licensing Board, dated I September 20, 1983, it has become apparent that this portion of my testimony requires clarification. The referenced EPA report is actually the second of a two part report: " Protective Action Evaluation Part I, 4 8310170356 831010 PDR ADOCK 05000454 0 PDR

the Effectiveness of Sheltering as a Protective Action Against Nuclear Accidents Involving Gaseous Releases, (EPA 520/1-78-001A)" and " Protective Action Evaluation Part II, Evacuation and Sheltering as Protective Actions Against Nuclear Accidents Involving Gaseous Releases, (EPA 520/1 001B)." The above quotation from my testimony was in the context of my discussion of a standard operating procedure which is used by the Illinois Department of Nuclear Safety (DNS) for deciding between evacuation and sheltering. The methodology used in this standard operating procedure is derived from Part II of the EPA report. The procedure closely parallels the logic detailed in the diagrams on pages 39a and 39b of Part II of the EPA report. The math-ematical formulae in our standard operating procedure call for input of the dose commitment reduction afforded by sheltering. We attempt to provide the sheltering input whenever possible based on data gathered in local surveys. (In fact, the above referenced standard operating procedure utilizes such empirically derived data when addressing sheltering versus evacuation scenarios at the four operating nuclear generating stations in Illinois. A similar data base will be developed for the Byron station by the time the site specific volume of the Illinois Plan for Radiological Accidents for Byron is completed.) However, if such data is

r s i i e i ) not available, DNS will utilize a dose reduction f stor assuming a single story wood frame building, the least protective type of sheltering. The factors for this input can be found in Part I of the EPA report. I used the term " single-story wood frame building" to indicate a wood frame building with no basement in which the only attenuation is provided by a single layer of roof and i ceiling materials. See page 16 and Table 3 at page 18 of Part I of the EPA report. As indicated at the referenced pages, the attenuation factor for such a structure is 0.9. As indicated in Figure 26 at page 72 of Part I of the EPA report, that attenuation factor translates into a dose reduction factor of about 0.6 (based on the parameters i presented in Table 6 at page 52.) Thus, the dose reduction factor we use in the circumstance described above is ap-proximately 0.6. i There also may be some confusion concerning my use of the term " conservative" in the above-quoted part of my testimony. As I stated in my testimony, the policy of the State of Illinois favors evacuation ~as a protective action since it reduces dose commitment to zero if timely achieved. i Thus, when unknown or highly variable factors are present, assumptions are made consistent with the State's policy. If the predominant type of structure is unknown or if there is i a significant mixture of structural types, the dose re-f ,m..._ _ _ _ _,, _ -, -,. _ _. -,,. _., _., _. _. _. _,.. _ -.., ~.. _,,. - _.. -,,.. _._.--..r,---._.---

_4 duction factor for sheltering used is that of a single-story wood frame building. This assumes the least amount of protection and thus assumes the greatest possible exposure from sheltering. The use of this assumption in the standard operating procedure will favor evacuation, and thus the assumption is " conservative" under most circumstances. The EPA report does not refer to this practice as conservative nor does it recommend any policy such as that adopted by the State of Illinois. Any inference that the EPA report endorsed our practice as " conservative" was unintentional. It should be emphasized that this " conservative" approach is applied only when the type of sheltering available is uncertain. We do not anticipate the necessity of using i this assumption at Byron since, as previously indicated, we expect to obtain data regarding the types of structures in the Byron area. To the best of my knowledge, the foregoing is true and correct. l - 64 David D. Ed SWORN AND SUBSCRIBED to before me this 106 day of ch 1983. 1 W M Rotary Public Ly C = %;% b? IRS 4nt & IE55 f j

_._ ____= g = .s. w l

• ~ r- ~-

==

=

o &^i2"77% GEPA Protective Action 'EVsluation Part I The Effectiveness of Sheltering as a Protective Action Against Nuclear Accidents involving Gaseous Releases -v-.,e--- --w,w-- --w= - - - w'=~ ' ' ' ' ' ' ' ~ ' ' " ' ' ' ' " " ~ ~"~"~' " ~ ' "

p:.n=.~ =.

---

u__,

~..... a,_ + LICAL NOTICE . This report was prepared as an account of work sponsored by the Invironmental Protection Agency of the United States Govern-ment under Contract No. 68-01-3223. Neither the United States nor the United States Environmental Protection Agency sakas any warranty, express or implied, or assumes any legal liability or i responsibility for the acc.tracy, completeness or usefulness of any information, apparatus, product or process disclosed, or represents that its use would not infringe privately owned rights. o f { r e I I [ .~

r o l = 4 PROTECTIVE ACTION EVALUATION ~ PART I O THE EFFECTIVENESS OF SELNIG AS A 4. FRUlu aavi. ACTION AGAINST NUCI.ZAR r..; ACCIDENTS INVOLVING GASIOUS RE:.ZASES APRIL 1978 1 George H. Anno Michael A. Dore Prepared for .i U.S. Environmental Protection Agency Office of Radiation Programs Washington, D.C. 20460 6- ' - w ee .m y =-- e -t* e 7'

1

• J; o.

Y .'[ 1 111 h-i ", J I POREWORD The Office of Radiac1on Programs carries out a national program designed to evaluate the exposure of man to ionizing and nonionizing ra'diation, and to promote the development of controls necessary to protect the public health and safsty and assure environmental quality. Office of Radiation Programs technical reports allev comprehensive and rapid publishing of the results of intra-

aural and contract projects. The reports are distributed to groups who have known interests in this type of information

+ such as the Nuclear Regdatory Cem=1ssion, the Departnant of Energy, and Stata radiation control agencies. These reports are also provided to the National Technical Inforsation Service in order that they may be readily available to the scientific community and to the public. . Comments on this report, as well as any new infor=ation, would be velec=ed; they may be sent to the Director, Environ-mental Analysis Division (AW-461), Office of Radiation Progra=s, U.S. Environmental Protection Agency, Washington, D.C. 20460. i ) A g I V^- t sa W. D. Rove, Ph.D. Deputy Assistant Administrator for Radiation Programs 6* e 3 J i s e e aN & m*m A*

F e .? iv FRZFACE The material contained in this report was sponsored by the u U.S. Environmental Protection Agency under the technical guidance ~ . of Md. J. I.ogsdon of the Office of Radiation Programs, Inviron-mental Analysis Division. Based on a study to assess the application and utility of sheltering and evacuation as specific protective measures in the event of accidental releases of gaaecus a radioactive material from nuclear power plants, -Jtis report is the first of two that deal specifically with the effectiveness of public. shelter structures The second report evaluates both sheltering and evacuation protection measures from the standpoint of providing technical guidance in fornulating emergency planning procedures. The purpose of this contract report is to provide a technical basis for EPA to develop guidance with regard to actions to protec: the public from accidental airborne releases of radioactive nacerial from nuclear power facilities. The information in ehts report should not be construed as guidance from IPA to State and local officials in developnent of their radiological emergency response plans. Such guidance will be published in the '?.anual of ? stective Action Ouides ~ and Protective Actions for Nuclear Incidents," currently under de-velopment by the E?A Office of Radiation ? ograms. The Inviron=entc1 ~ Protection Agency is =aking this report available as a source of technical infarmacion. 0 + pe me 9 O**M* 6 h =e6 ha Oew

= ? ...........m..x.....,, I t-V ~ TABLE OF CONTENTS PREZACI.............................. iii LIST O F FICURES.......................... v11 LIST OF TABLES.......................... ix INTRODUCTION......................... 1 II. 'IS. 3 RADIw. SOURCES.................... 3 SHELTIR ST m _ 'MDEL 5 - FALLOUT CAlefA-50URt.f 7*UATION. 19 TDfE-FRAE MODEL..................... 23 DCSI REDUCTION FACTOR................... 32 DOSE COMPCNINTS-UNSEELTIRED... 35 DOSE COMPONINTS-5HELF................ 3 7 SEELTERING AND EVACUACCN. 43 III. RESULTS........................... 51 17. CONCLOSICNS AND RECCtCE:CA!!CNS.. 85 Appendix A: Failout Cama Source. 9I t j Appendix 3: Dosa Reductica Fac:or..... 94

1. ArNCES..

103 9 i i 1 d I w-- 4-r y.-.

a. -,u. i .j,. vi 1 i TABLE OF CDNTE:.'!S Fig. 1-Attenuation Comparisons-In' finite Water Medium .... 14 2-Shelce:-Structure, Cloud Camma-Ac:enua:1on Geometry.. 15 3-Attenuacion for Strue:ure Walls and Roof--Cloud Sourca 17 4-Finita Cloud, Gamma Dose-Correc:1on Factors Versus Camma Enargy............ .......... 20 5-Finite Cloud, Camma Dose-Cor:ee: ion Tac:or Versus Effec:1ve Shel:er Radius........... .... 21 6-Camma Ac:enua:1on for Scrue:ures-Tallou: Source. 22 7-Tinite Plane Source, Geonecry-Correction Factor for 1 MeV Gammas.... ............. 27 8-Shel:aring-Model Tine-Fra=a. 29 9-Shal:aring and Evacuacion..... 45 10-Air Exchange and Infil::ation 14:as in Closed Passenger Compar:.an: k'han Air Condicioning is Set at a Maximum. 47 ll-W3 DRF Va'rsus T (! =0,7 =1) .......53 g L a 12-Thyroid DRF 7ersus T.,. (T =0,7 =1) 56 1 a. 13-WB DRI Ve rsus T, (T =0, ~ =C), L = 1.......... 57 14-W3 DRI 7ersus 7,, Case A, (T =0,7 -0),

7...(T -0.25,7 -0.5),

7 2 t.=............. ........Sa 15-WB DRF 7ersus 7,, Case 3, (T =0,7,=0),L = 1................. (! =0. 25, 7 =0. 5 ), .......59 16-W3 DRI Versus T, Casa C, (7,=0,7 =0), (T,=0.25,T,=0.5), a 1 I.=.,... ........... $Q l 17-k'E 7,17 versus L, (T =0,T "C'T "l) 2 a 62 IS-Thyroid DRI versus L, (T, =0,7,=0,7,=1). 63 19-W3 DRI Versus L, Case A, (T =0,7,=0), (7,=0.25,7.=0.5), 1 6 .,=.. ....o4 i =___ _ _ e m68- ,,,e- ,y y ..v,.

, v.~ n _._ ,1 t s vii Fig.~ 20-WB DEF Versus L. Case 3, (T =0,T -0), (T =0.25,T '0*5)'.65 4 T, = 1.......... g..

2..... g...

2...

f 21-Wa Du Versus L, Casa C, (T =0,T "0)'. CT =0.25,7 '0*3) '. 66 3 T, = 1.......... g..

2..

1...

2...

22-Thyroid DEF Versus L, (T =0,T =0), (T =0.25,T -0.5), T, = L......... g.........

2......

6 7 g 23-WB DEF Versus T, Casa 3, LS, T, = 1.......... 69 2 24-WB DRF Versus T, Case 3, SS, T, = 1.......... 70 2 25-Thyroid DEJ Versus 7, Casa 3, T, = 1.......... 71 1 26-WB DEF Versus T, Casa B, SS (A=0.4,0.6,0.9,L=0.125,

1. 0, 2, 0 )..

2.....................

71 27-WB DEF Versus T, Case 3, LS (A=0.05,0.1,0.2,L=0.125,

1. 0, 2. 0 )..

2.....................

7 3 28-WB DRF Versus T, Case 3, (T,=1,7 *0)' 33 (L*C*3'1* 0* 1.5), LS (L-2) 1........ 1 75 29-Thyroid DEF Versus T, Case 3, (T =1,T.,=0), L = 0.5,

1. 0, 1. 5, 2. 0.......... *.

7......... 76 30-W3 and ~hyroid DEF Versus T, Case 3, (T,=1 T =0,L=0.125) 77 g 2 31-W3 and Thyroid DRI Versus T, Case 3, (T,=1 T =0.25,L=1.0) 78 2 32-WB DRI Versus Iodice Ingrass Frac:1:n. Case 3, (T =0,! =0,T,=1).................... 79 2 33-Shel:aring with Evacuatics, 'n'3, SS-Transi: T1=a Versus Shel:er Ti=a (T,=0.5).................. 31 31.-Sheltering vich Ivacua:1=n, W3, LS-Tra:si Ti=a Versus Shel:ar Time (T,=0.5). ................. 32 35-Shel:aring vi:h Evacua:1cn. ~hyroid-Transi: T1=a Versus Shel:er Time (T,=0.5)................... 33 e emusumme ,m.,,-m,, = ~, -,.,y_-w - - - - - - - - -, - = - - - - - - - - - y --,-y.we- --. =-- y-,. "'i-,v.: -w -.m=

.~ -? v111 ,a LISTOFTA3[.IS s Tabla 1. Radionuclida Sourca Data................. 4 2. Air Changes Taking Placa Under Average Conditions in Easidences, Exclusive of Air Provided for Ventilation. 8 3. Representative Cloud-Canna Attenuation Factors..... 18 4. Reprasantative Raduction Factors for Surface Source.. 24 5. Dose Conponents..................... 34 6. Fixed Paranatar Sunnary................. 52 ma 68 te e e e I,b-- ~T - " ~ " '

m_. 1 I. INTRODUC* ION In the event of an airborne release of radioactive material from a nuclear power plant accident, shal:ering of individuals is an important consideration in emergency protective action planning as it may be 1) an effective means of significantly reducing radiatior. dosages; 2) th's only practical option in view of possible time and logistic ecustraints. Moreover, most people in urban areas, for example, spend 75 percen: of their time indoors. This report describes an analysis to estinate the effectiveness or benefit that might be derived from shel:eri=g following a release of gaseous fission produe:s from an operating nuclear power station. Tha objec:1ve of thi.s effort is the development of sheltering effectiveness information that could provide general guidance to hose responsible for ferzulating required emer ency plans for nuclear power plan: siting. g Accordingly, the approach P=kan here does not land 1:seli to :he specific evaluation of shelter structures involving deca 11ed descripcions and operational scenarios; but rather focuses more broadly on what are deemed to be the essential paramecers and their variations, ar.d the general characteristics of small and large categories of shel:er s: uctures available to the public. Shel:er effec:1veness as referred to in :his report is the ratio of the dose that may be incurred with sheltering condi:icus to :hac vi:hout shal:ering in the open, specifically defined as the dose redue:1on f actor (DRF). DRF estimates for different con-dicions of source release, shal:ar s: rue:ure assumptions, and operacional time parameters are made for both whole-body and thyroid doses separacely, based on a single-compar:sent structural model of the :i=e-varying out-side and inside gaseous radionuclide sour:es of krypton, xenon, and iodine. Design basis acciden: (DBA) assumpeions are made for the gaseous radionuclide release to defins :he proportion of rare gases and radio-iodines. The =agni:ude of the. release and dose es:imates are based on radionuclide data f rom.~':s.:scrror Scfe':y S=d.f (*. ASH-1400) [1]. How-ever, inasmuch as the DRF, as defined above, is :he key index used :o characterize the effectiveness of shel:ering, i: is no t se=si:ive :o :he o~ e,-- c.-, - - --., - - - ,,,.n

1 absoluta sourca relaase magnituda insofar as an approximate proportion-ality 14 maintained among the individual radionuclide sources. Sourca ~ ralasas cima and duration assumptions ara related to ralaase categories given in Raf. I as PWK 1, ?W13, and FWR 4, for which release cimaa e rangs-from 1.5 to 2.5 hr and the release duration ranges from 0.5 to 3 hr. The basic shaltar modal characteristics considered are gaarm ray t ~ attenuation, sourca gacmetry, gaseous fission-produe: ingress, and air change rata. Numerical values used for D17 r=1*"1=tions are based on a 11:aratura review and some assumptions that are nada whera data ara sparse or lacking. Temporal parametars c=nsidered are sourca release :1=a and duration, cloud travel time, and ti=a span: in the shaltar structura. These para-matars are used to illustrata the sensi:ivi:7 of shaltaring affectiveness to variations in parameter values. Also, the analysis of shel:ar effective-nasa is based on a time-frama model, which can be conveniently related to other operational timas 1:apor. ant for amargency planning (e.g., in-formation time-delay and reaction time) required to accomplish the pro-tactive ac:1on-in this case, sheltering. In addition to developing shal:ar-affectiveness estimates parametrically, the advantage of emi:ing and evacuating the vied'd:y of the shelter area after some ini:141 time in the shelter is analyzed from -he sta dn point of the CRF and temporal considerations. h* m' f a ? L i w, f {

• • • m=e-

+=. ..m

~ --. = - n 1 1 3 4 I II. NALYSIS .e RADIONUCLIDE SOURCIS Tabla 1 gives the radionuclidas and associated data used in this study to sisatiata a, fission-produe: ralassa of the rare gases (Is and Ir) and the significane radiciodin's. n a Is, Ir, and I :adionuclide sourcas e and parameters shova are assencially the same as those given in WAS'd- ' 1400, AppearH r VI (1), with the exception of Ia-133m and Xa-135m, which have been added for completanass only, since they would not affec: results significantly. Tission-produe: source inventory data based on ORIGIN Code calcula-tions (2] vare used :o sstima:a the Xa-133m and Xa-135m sources lisbad in Table 1, based on a 550-de/7 irradiation period (same as Raf. 1). Sinca che decay half-lifa of I4-135m decaying to Xa-135 is shorr (15.6 mis) considering the cimas of i=carest (hours) in this study, tha asci-mated shutdown zero-t1=a Xe-135m isvancory was added to the Xe-135 sourcs on a mass basis and conver:ad to Ia-135 on an ac:iv1:7 basis, which isc:aases to 0.27 C1 instead of 0.26 Ci given for Xa-135 in Raf.1. na atas:abla decay half-life for Ia-133 is by comparison appreciable, and no s1=11ar adjust =ent for he Ia-133 sourcs inventory was =ada. na average decay gan=a energias lis.ad is *ab'la 1 for the matascabla Za radionuclidas were takan f:ca Raf. 3 (pp. 32-33); the whci.e-body ('a'3) cloud gamma-dose factors, from Appendix D, 3sf. 1. These dose factors for the ground-y (surface deposi: ion sour:a) do :ot taka ground roughness o into effac: (such as a fac:or of 2). n a estimatad effec:iveness values in ta:ns of a desa-reduction fac:or would not be affected significantly whether or not the ground roughness adjustment were included. An as-hea of the average ga=ma decay anargy was made for the sourca nuclides to serve as a guida is 1) esti=ating gamma ray at:anua-tion factors for shal:a structures a=d also is 2) =aking esti=a:ad adjust =ents for fini:a source geoestries of cloud-source volume and con:amina:ad ficor-surface spaces inside :he s::ucture, sisca :he dose fac: ors for cloud-y and ground-y apply :o infisi:a sourca gec=etries . - -. ~ ~ . m

l . + m. l Table 1 l RADIONUCI.1DE SOUNCE DAT4 4 Dose Factors Italf-Li fe Source Average Ceana NucitJe (lir) (Curies i 10 ) Energy (Hey) Cloud-y Ground-y 175D . Thyroid (res/sec) (ren/lir) (50-yr) (50-yr) (q) (E) ( gj_3) g7,2 (ren/C1) (rea/C1) Kr-85 93,600 0.006 0.0 0.0 0.0 0.0 0.0 Kr-85= 4 32 0.26 0.16 0.036 l l l Kr-87 1.27 0.52 0.82 0.36 Kr-ud 2.78 0.76 2.21 0.42 Xu-133 127 1.7 0.08 0.007 Xe-133m $5.2 0.048 0.23b 0.0075c Xe-135 9.12 6.2ya 0.26 0.06 t Xe-135m 0.27 0.27" 0.528 0.0972c 1 1 I 1-1 31 193 0.85 0.39 0.09 2.8 2,600 1.47s10 l 1-132 2.4 1.2 2.3 0.55 17 130 5.3 104 1-141 21 1.7 0.63 0.12 3.7 570 3.96u10 i [ I-134 O'.864 2.0 2.4 0.6 16 40 2.5x10 i 4 l, I-135 6.72 1.5 1.45 0.42 12 290 1.23:10 l I, duaued on Refs. I and 2. is il b j' Ref. 3. l Hef. 4. I 6 4 i I e I ~ l

( -~~ ~ 6 e e ? 1 1 3 (discussed below, p. 13ff.). The average gamma decay energy was estinatad to be %1.2 Nev, based on :har following simpia weighting relationship: 4 ~ j j,(I ) Zu (z)- D,,,(x,) j where Q and E are the radionuclida source ac:1vities and gz=ma energias, 3 respectively, listed in Tabla 1, and u,(E)) is the ganna-ray linear energy absorption coefficient as a function of energy for air given is Raf. 5. The estimata of the average gamma ray energy was based on a sumsation Jver all the radienuclides shown in Table 1, vi:h the exception of Xe-135m-- agais becausa of 1:s short half-life for the times of in:aras: in :his study. The gaseous radionuclida data in Table 1 are used to escisata shel:ar effectiveness is dosa redue:1on by summi=g each nuclida con:-ibu-tion (assuming single radionuclida daczy) :o ebcain :ha unprocaccad (out-side shel:ar) and protected (inside shal:ar) dose. Design basis assu=ocians (DBA) are made for the sour a ralaase--100 percanc of the noble gases and 25 percant of :he radiciodinas available for release. SHII,"IR STZUC"URE CDEL A simplified approach rather than a detailed inves: iga:1on was adopted :o account for. hose factors. hat migh: con:ributa :n the bene-f#.:s of seeking scrue: ural shal:ar in :ha event of a gasecus, radioactive fission-produe: release from a nuclear ;cwer faed ":y acciden:. ~aa reasons for :aki=g this approach are as follows: 1. Explici: consideratica of all types of possible structuras that may be available for shal:ar-single-family dwellings, apar. ment buildings, office buildings, subways, tunnels, fac:orias, and vehicles, etc.-=vould require an analysis. beyond che scope of :his effor: because of :he large varia-bili:y in :he para =eters : hat decarnice effec:iveness.

---

r-

. ~.,

- - ~ ~.-.... 6 2. In many instancas, reliable parameter data en not available; e.g., the actual chemical / physical for= of the "gasecus" constituents at some distant point from the sourca release and.the ingress of, in particular, radiciodine into shaltar 9 st.uctures. 3. The main purpose of this study is base served by providing s overall to:hnical guidanca information as to the effectiveness of usiog a shaltar structura based on some assumed conditions for shialding and ventilation races without specifically focusing on data 11ad physical description :nd analysis of shelter structures. After a raviav of tha 11taratura dealing vich the kay para = scars of this study's si:splified model (in keeping with the above reasons), calculations vera perfor=ed using paramatars selected to simulata what this study classifies as "small" and "large" structures (55 and LS) to illustrata the relative affectiveness of typical single-family dwelliags and of largar structures such as offica buildi gs, auditoriums, apart =ent ccuplazas, etc. In develeping the shelcar model, consideratice was given to account for the. following possible avenues of exposure to shelter i= habitants: T.xtarnal k1 dose from airborna cadioactive material both o outsida (shieldad) and insida (unshielded) the shelter structure. Inhalacion kB and thyroid dose frem airborna radioactiva o matarial inside the shelter structura. Excarnal k~d dose from radioac.1ve falicut satarial deposited o both outsida (shielded) and insida (unshieldad) the shaltar structure. In this study, beta skis dose was not eensidered, as it is assumed to ha of secondary i=portanca as compared vich kB and thyroid dose con-l siderations. The extarsal k1 doses (cloud-y and fallout-y) are based j sotaly on radionuclide-de:av ga==a radiacien in which both shelter-l structura accasuation anc finita sourca gecmatry factors ara included in the sodal as discussed below. l l -~ \\ 1

i '? I 7 [ The entry of outsids airborne radioactive cloud material is assumed to ha dependent on the shelter-structure ventilation race (forced, natural, or both) assuming constant homogeneous 31xing based on simple one-compar:- ment outside/inside air swehange. This type of stirrad-cank. Meg and ven:11ation model has been :.pplied in studies of the relationship between indoor / outdoor pollutants (e.g., NO, N0, CO, and 0 ) and has predicted g 3 concentration versus cima profiles that are similar to those seasured (5]. The radiciodina fallout deposi:1on inside the shelter is then also assumed to be dependent on the ventiIacion race as well as the fallout deposi: ion ~ veloci:y; these aspects are also discussed below. Sheltar St ucture ventilation A review of literature on ventilation races of homes and buildi:gs indicates a vide variety of air change escisatas ranging anywhere from M.L to 6 per hour for single-family dwellings :o N1 to 9 changes per hour for large st:uctures. The vide ranges are, of course, due :s the various t/ pes of construction--whether the portals and vindows were shut or sealed, and such environmental factors as vind speed. e=pera-ture differential, and humidity. Also, in some ins:ances, i: was not clear whether air change races included internal forced-air systens. A review by F.andley and 3ar on (7) of published infor=ation on home ventilation rates resul:ad is their suggesting the use of the range frc= 0.5 to 1.5 air changes per hour for homes and 2.0 air changes per I hcur for moders high-rise apartment buildings. A check vi.h comercial homa air-condi:ioning and hes:1sg vendors seems to generally suppor: those recomenda: ions. For example, usually a 4-ton (1500 cis) uni: is recomended for a 1500-f:2 single-fa=11y dwelling vi:t from 10- :o t 20-percent outside al: =akeuo. Such an ins:allation resul:s is f := 0.3 i co 1.6 air changes per hour with ou: side air. Of course, some systa=s i are installed for comole:e internal recirculation with no ou:sida air i makeuo other :han nor=al expec:ed s::ue: ural leakage. Municipal code requiremen:s for building ventilation races .or [ hign-rise office buildings, large apar =an: cc plexes, audi:oriu=s, ( etc.-also ses= :o suppor :he value of :Vo air changes per hour as I suggestad by liandley and 3arton (7]. For example, a check w1:h :ha i ~ ~ m + - - -. ,-_-,m-m. -y ,e

-~ i 8 Health Division of the Los Angeles Ci:y 3uilding and Safety Department (8] indicated internal air turnover cine of from 5 to 10 min depending on occupancy requirements, with a representative value of about 7 min-with 15 percene outside air makeup as a comfort-level requiremen:- which corresponds c~ o 0.9 and 1.8 air changes per hour and $1.3 atc.unges per hour. Considering the above data, the races for single-family 6 dwellings and large structures are generally comparable, assuming internal forced-air systems. In the absence of forced-air ventilation systens, home and building air change races would. be expected to vary much more videly-as indicated. by the published data av==*ned by Handley and Barton (7].This conclusion a.a also supported by observations of Yocos, se al. [9] who nota that particulate pollutant levels are lower in public buildings than in homas. The ASERAE Rardock of Tundanen*rls (10] points to the lack of published data. on air change races for differen: buildings, exclusive of air pro-vided for ventilation, when utilizing the air change method for estima-ting infiltration requires experience and judgmenr. Table 2 gives A.52RAE Ecrdock values that may be used with reasonable precision in making infiltration estinates for residences with differen: room conditions. Table. 2 A13, C3MCIS TAK::NG FiACE UNDER AVERACE CONDCIONS IN RESI::ENCIS EXC:.USIVE OF AIR PRCVCED TOR VENTI:.ATION Kind of Room or Su11 ding ""I'* .aking Place per Hour a Rooms with no windows or ex:erior doors 1/2 Rooms w1:h windows or exterior doors on one side L Rooms with windows or ex:erior doors on two sides 1 1/1 Rocas with windows or exterior doors on three sides 2 Entranca halls 1

• 7er rooms with weatherstripped windows or with scors sash thema valuas.

, use evo-thirds e The other is the " crack nethod" based on naasured leakage charac:ar-1stics of the building conponen:s and selac:ed pressure differences. i i e - 6 yy_-, -.p_ g.,,, -y ._y ..,r- ,,,,,.,,.__,,.g, g,--,..

r=. = _ - 1 9 s; Another approach in making a1: changa estimates due to natural ventilation for houses is given by Coblentz and Achenbach (11], rho suggest the following empirical relationship in which the air change sta is proportional to the outside vind speed and inside/outsida tempera:ura differential (i.e., vichout insida forced ventilation): I (changas/hr) = A + BW + CAT whera A = air change rata for W = 0, AT = 0 (0.12 to 0.18), B = 0.013, C = 0.005, W = wind speed, sph, 4"*

• Tinsida "" Toutsidk' Assum:.cg the upper IJsic of A = 0.13 and a! = 20*T gives air change ratas of about 0.35 per hour for a 5-eph v1=d speed and about 0.5 for 15- :o 20-sph visd speeds, which appears to be somewha: on de lov side cespered with other data reviewed. This diffarance, however, may be due :s new, well-built houses that made up part of Coblen:: and Ache = bach's field samplas. In contrast, measured air changs ratas given by Megav (12} for a hut structura cat vers =ada is conjunction with radiciodica pene::ati:n exper1=ents were substantially higher, rang 1=g anyvnera from abcu: 2 per hour to 8 per hour (the latter, hevever, for open vindevs). An exa=1:a-tien of Megav's data reveals an indication of air. char.ge-rate proper:1:nali:7 with outside vind speed : hat, roughly, was abou: 0.5 (changes /hr) per (ni/hr). This figura cor ssponds :o only an "eyebal*," esti=a:e f m

,I Megav's data, whi d are complicatad by variations in vind direc:1on. Such variatiens would give rise to differes: pressure differes:ial dis-tributiens dus :o as p ::1c flow pat:ar:s, which would affect de is:e=al air change :sta. 3ased en :he above review of air change rates : hat =1gh: be expec:ed for single-family dwellings (small strue:ures) and various building s::ue:ures ca: could be used as : =porar/ public shel:ers, values of fres 0.123 :o 3 air danges per hou vere assu=ed is perf::=ing shel:er-strue:ure effec:iveness calculaciens. :: vas fel: :na:.0.123 :hanges

- aw I 10 ? per hour might represenc relatively " tight" structuras (either large or small) and that. N3 air changes per hour might represent a practical upper limit of structursi ventilation. Of course, as indicated, such larger values of 6 en 9 air changes per hour have-been measured; but it + r was felt that these values would represent extreme cases (e.g., open windows or portals), which do not represent practical cases if good p1mmiing is assur-4. Caseous Fissien-Produer Ineress Thaextanttowhicaradiciodinewillp[tnetrataastructuralshield-ing facility is dependent on the gross tightness of the structure, the ventilacion race, filtration, and the chemical and physical properties of the released material and the interacting species. Many of these facets of a gaseous fission-product ralsase from a nuclear accicant are currantly unknown, particularly for radioiadise, which leads to difficulty in accurataly predicting the ingress of gaseous radioactive saterial into sneltar structuras. For the rara gases (Ia and Kr), most are willing to accept virtually no effective " structural filteri=g," because of chair inertness and stability as gaseous for=s. Accordingly, in this study no effective f11 caring action has been included is esti-nating their 1 carnal structura concentrati:ns. For the halogens, which are here assumed to be all radiciodises, the case is mora ecuplicated and suffers from scarcity of exper1=escal work on indoor / outdoor pollutant-level relacionships dealing with the ingrass of radioicdine into various pccential sheltering structures. The radiciodises are of course particularly important sourtas due to their large cont-1bution to the WB dose, as well as bei g totally responsibla for the thpfd dose. Thraa known chemical forms of radiciodine present as airbor=a gaseous species in power-station areas during and after handling defac-1 tive fuel elements are elemental iodise (1 ), hyp,cidous acid (HOI), and 1 organic f odidas (CH I). The estio of the three species vould depend 3 i on the conditions under which an accidental release might take place. Elemental iodi=e is thought to be the pri=ary for= teleased frem uranium-oxide fuel. It hydrolyras rapidly is water, generating HOI, or l l = (

~~-- - -- f = en. 2 11 it forms organic iodidas through a slower reaction with organic com-pounds, wi:h relative stability la air increasing in the following

• order (13]:

i e I e 50I e CH I g 3 The actual chemical / physical form of the radiciodise that would be present at some off-site pois is yet another ques:1on; however, pro-bably very 11::la procaction would be offered by a strue:ure against the ingress of E0I and CH I, both unreac:1ve gaseous forms like X4 3 and Kr (14]. Uta Recetcr Scisty St.dj (1] did consider othc possible forms of radiciodise tha: could be released (e.g., HI, CsI, and ZrI), but concluded tha these forms would not be :ajor species as : hey had not beert verified es.perizantally. Is 1:s dose calculations, Ref.1 assumes, primarily, elemental iodine; and, to a much lesser extent, ~ organic iodide (approximately a !ac:or of 100 less). However, assuming elemental iodine release to the at=osphere, con: rolled field release tests [15] involving elemental iodi=a (! -131) indicated a rapid ::ans-2 for=a: ion in apparen: psr icle si:a from the source-- in :ha: :he fiald sampling results for the released gaseous product (eff ective.'c") =2$) revealad a much broader spec: un of sizes, closely rese=bling the normal dia: Chution by size, of par:1cles is the at=osphere (.1:h an.'efD = 0.4 microns). The above would sugges: some effec:1veness of shel:er s: ue:ures in reduciss radiciodice ingress released is :he ele = ental form, depend- ~~ ing, of course, on overall i=regri:y, ventilation, fil:ering, e::. Is:1:naces of radiciodine ingress is:o s ue:ures for :his s:udy are pri=arily based on :he observa:Lons and work of Megav (12], which repre-sents essencially :he only source of published i=formatica applicable to this study; other rela:ed, bu: so: applicable, work (16] has been sponsored by the Office of Civil Defense ("Jefense Civil ? aparedness Agency). Megaw's work origi=ated fr:m :he acciden:a1 Wind scale inciden in which 1: was estimated : hat dose ra:es inside build-ists.ay be from abou: 14 :o 15 per:an: of : hose ca: side. Subsecuen: experimen:a1 seasure=en:s were =ade by Magav involvia; racisi:dise k e 46he 6 /"a

i. i. i -12 releases and, a reasonably tight wooden hur; and he concluded that the a t1am integral of the insida concentration (dose) any be from 20 to 80 pee'canc of.that outside, depending on wind velocity and direction. - ;y An a*==in=tica of Megaw's published data (12] does.not suggesa any correlation of the inside-to-outside dosa ratio with either outsida wind s . velocity or ventilation race, probably because of the varying conditions under which measurements were made; e.g., naasurements were made for unique sets of wind direction and velocity. A simple. statistical analysis of the data indicates a protection factor (ratin of inside to outsida dose) of 0.51 0.11 (pooling the data from two experiments described). From Megaw's work., however, it is not possible to identify precisely the ex:ent of the radiciodine fil:aring action or resistance to ingress for use is a simple miring model such as is assumed for this study, even for the case structure used in the experisen:, because of the absence of experimental infor=ation regirding source relassa time and i=censi:y distribution and tha absence of any correlation of the inside-to-outside dose ratio with ventilation race. The dose reduction fac: ors given by Megav are therefore effec:1ve values :ha: wouli include any filteri=g or ingress ac:1on of he sheltar struc:ure used in :he experiment plus the specific test conditions and parameters. *dovever to taka into secount what is felt to amount to some gross filcari=g action for radiciodise-whether assumed to be due to trappi=g or deposition in small cracks or openings-the above-mentioned value of 0.51 has been :aci:1y assumed in approximatisg the explici: fil: art =g ac:1on for shel:er structures. Radiciodine Decosition Shel:er effectiveness estimates is :his study take into ac:cust 1 external '43 dosages from outside and inside radiciodine source deposi:1on. i using escisaces for the deposi:1on veloci:y, V. Values ranging from g 0.1 to 1 c=/sec were obtained fron controlled environmental radio-iodine tasts made at the National Reac:or Testing Station in Idano (:.5]. ] < ; Tor outside radiciodine deposi: ion veloci:y, the Rect.:ror Safa:y Sc.zdy (1] -used a value of 0.5 cm/sec, enich is also assumed in :his study for surfaces outside a shel:er strue:ure. = m.g e

• ~

e e.-e.--a D+e' N

• Su

-,,----.m- .,,,.,,.y.w. ,w.+ --w,-, w,--.y- .p.- ,f.- as -, -,. - e,-,..,,-m.s=c---ww r,.,",r-e-.-

1 ~ s ', i e 4 13 et

• \\g.

y i j Instds a shelter, a value of 0.025 cm/see was asr.umed for the radio-1 i todird deposition velocity for the floor surfaca, based on Megaw's 1 e vork in which he. estimated. the insida deposition velocity to be only s abou: $ percent of the outside deposi:1on velocity (12]. Cloud-Ga=ma Attenuation .The a :enuation of cloud-gamma radiation that might be afforded by building structures has been estimated by Burson and Profio (17]; the results of their analyses ser sed as a guide for esti=ating the cloud-gan:na' attenuation fae: ors used in this study. The sourca basis for the at:enuation c.alcula:1ons that vera perfor=ed applies to the Pa*R Category 2 ' accident (17] ten miles from :he plant, under average dry meteorological conditions. Figure 1 shows comparison of mass-path attenuation for different energies based on dose buildup and exponencial at:enuation in water. Since, for the sourca energies of interest, most of the attenua-tion vill be due to Compton scattering--where Z/A r**2d-s rela:ively* l constant at about 0.5-water data (mass-path) are suitable for applica-ties to the usual structural sacerials such as wood, concrete, brick, and even steel (17]. As shown in Fig. 1, for mass-path thicknesses 2 of incares: up to 45 gm/cm, attenuation values-particularly, fo: rrsac:or-accident spec:ra (ground and cloud source) and Co ara \\ all quita close. Moreover, slight variations in the spec: rum are cet s considered significant, sinca che higher-energy gem rays would be -Jie most penet:ating and any differences in at:enuation vould act .C amount to any sajor source of uncertainty consideri=g the other assu=ptices made in this study. 3urson and ?rofio's attenuation fac: ors (17] used in this s:udy are based on calcul.ciot.3 ass" d g a simpia hemispherical shell =cdel (Fig. 2). Estisacas ere made of :he ga==a attenuation (with the dose poin: at c:a origin) for :.' e portion of radioac:1ve cicud nacerial cu: side the shal:er, based 'on nu=erical evaluation of the attenuation, A(x), given by a rela:iceship of :he form -- n

[ -- 0 i. l 14 1 1.0 ; 0.8 _j l% l .:1 l . 7.. f\\ A i I l g 5 0.6' k i, l' .t .g ~ \\. .u i. 0.4 .L. o ".U l = 4.- f t c o \\ w I L .\\ = \\ e es. \\ reacter ground sourca \\ 1.12 hr fissien accident cloud sourca \\ \\ 60 P*"C 3 Co s 0.2 ~. \\ \\ \\. 1 \\ 137 Ca i i i I. e e 0.1 0 10 20 20 40 50 60 70 2 Mass thickness, x (gn/c:a ) - Fig.1-At:anuatien c::::::ariscns-infinita watar ::edium -O 6N.

=

.____-_-_l'_T-___.____

+. - b -A_, ~K e t. r s 15 i .0 IV / dr/ (out) r X A-a .. _u, - --- a. s.. -e,... .e . : A :-u,;>w ~sr.s _v., m, - e, .-r

7. ~

.=.s . m -.M t.. -a.., ; &f

• r..

s .n p&m' C$*;f. 5.W - g .u. ' ' ~ " '. UM.S*"'$i M L-a.').,w,h# d'**Y,Y[.*~.I- "'c -

• [15.-

[* e,.s g. %.7.*i*.no i:h..'d.@s.. e'.did. ??~ di../'%..,- .~ .w 3Y

--. As. -

".L-+ m. e +

?: & s~ gr

=

s,. e' m. ..,-.a - 2,. dsti.gp~yn m, :. d.J* .m.,42* c %*i-c.: T

• N rer

".4. .... ter..:.,.. 4y. gs...J 4.._. ant.u-w* .. -. 9' * :- %. - e-~ wsn. ..s $c.

• • y.7.. W. - p Jt.e w$ i- ; ;;;,. ~.%.

?*.,:"J . u,2. s....- a--. '.17 L., e..+, a, wf m--.t,%.',..J._... $_,q. -'t f .4J..,r -#d+.ui g 4"-W#. g,.. - - * .. g v.r -m_- -s. -."s- - A_ te,_.. e.s.,.s.....y.e o..%. 4 t ///////////////////////////////////////////////////////////////////i///////f f //////f///////j/j f/j f f f f ///f f f,/jjf f ff ff /f f /f jj/, t 1 1 j Fig. 2--Sheltar-structure, cicud gan::a-attanuation geccetry i ( 1 i i om, M em e m. -,,,.c._

.~. j t u i -(n r+v x) EF, 3(p **"w*)

• a e

l gasmia. a as A(x)

• A ES, 3(p,r) e dr energies whers u, and u, are the energy-dependent gamma-ray absorption coefficiones for air and water, respectively; and K and. 5, are the anergy-dependent dose-conversion and volume-sourca terms, respectively; and 3 is the dose buildup factor. Figure 3, a plac of the gamma ray accanuacion for acciden: opectra for a = 3 m and ua = 3, is applicable for escinating gamma ray ac:anuacion for structures of a wide variety of enclosura sizes (effective radii, a),

since A(x) is ralatively insensitive to a, because of the low densi:7 ~3 3 of air (1.293 x 10 ga/cm ) as compared to structural material. Also, very lic:la dose contribution would be expected from cloud sourcan beyond about three mean-free paths in air; charafore, ul = 3 is a reasonable approximacion for an infinita cloucL sourca with regard to tha gamma-radiacion transport considerations in this stady. Tha estimacas of gamma attenuation for an outside radioac.ive cloud source chat can be made from Fig. 3 depend on tha scrue: ural assumptions. For example, for a wooden frama house with roof and ceiling consisting of 1/4-in. vood or asphaic sh1=glas, 3/4 in. of wood shasching and raf:ars, and 1/2 in. of gypsum board, cha mass thickness would be ( 1.5 (in.) x 2.34 (ca/in.) x 0.84 (gm/en ) = 3.1 gn/cs' where A(x) = 0.9. Bet:ar protec:1on would be afforded by a small house _ ith a wooden roof and masonry walls. For example, assuming half the w 2r solid angle (Fig. 2) to be subcended by the walls and the other half by the roof, che overall at:anuation. fac:or would be meem. W** y-_-

---

.-__---y-

,..,p.>7-y _,.-7,,p ,,--,.-www .y 39 g ,,,-y%--- -yw,--

s e 17 s '0 g..... iTi i i i I !_ _ 7 . _.l ..t i -- t 0.8 t i i i 4 i 0.5 i nx w< 0.4 - .s. .O*v. e .O. a. 3eu es M< 0.2 I l .n s 0.1 0 10 20 20 40 k0 d0 70 Mass thickness, x (sm/cm ) Fig. 3--At anuation for structure walls and roof--cicud scurta __.--y_

~. - - - - -.. ? t3 i. O.3 x (0.9) + 0.3(0.38) = 0.64 I j where the attenuation for the vaus. (0.38) is. based on a vau-sass thic3c-ness of 4 (in.) x 2.34 (cm/in.) x 2.7 (sm/cm ) = 28 gn/cal (assuming 8-in. concreta b' ricks with a 50-percent void. volume). Attanuation of cloud-gamma radiation for large structures such as ~ offica buildings and multiscory structures could be signi'icantly more than for simpia structuras such as single-family dwe11**gs. Attenuatica of 8-in.-chick solid concreta, either exterior valls or incarior vans (e.g.; fire-resistant stairvens) may be equivalant to mass thick =ess 2 of around 45 to 50 sm/cm, corresponding to accanuation factors of 0.2 en 0.17 (Fig. 3). Tabla 3 st====r1:ss representative cloud-gamma accanua-tion factors for the types of structures noted. Tabla 3 REPRESENTATI7E C. CUD-CAMMA A4.uiUATICN FACTORS Structura Attanuation Factor Wood frame house, no basement 0.9 Masonry house, so basement 0.6 Basement of wood house 0.6 3asament of mascur/ house 0.4 I.arge offica or industrial building 0.1 or less The above values do not suggest any substantial protection fr=m axternal cloud-gamma radiatica afforded by lightly construccad, frana single-family dvat t 4,gs. In this study, however, ascinates of shaltar-ing effectiveness vara sada assuming somewhat mora substantial ga=ma-attanuation procaccion. A(x) = 0.1 to 0.9 for small se:uctures. For large .,.-----m.- ,.7 _,--.,,_-.-,y-+-,,,m.w,.p,.9 y,,-.y9-----..m_., g.,c ,,,-,m,.y ,e m

s r '/$. 19 4 st=uctures, shaltar effectiveness estimatas vara anda for A(x) = 0.05

• b :

n, to 0.2; gasuna attenuation could be even greater, amounting to valuas j, such less than 0.05 for well-protected areas within large multiscary structures. [ The estimated external WB gasuma-dose contribution'from airborne gaseous radioactive material that enters a shaltar structura is based on a fisica cloud-sourca geometry corrae:1on fac:or, sinca infinica cloud-dose conversion factors (Table 1) are used in estinating shel:ar effectiveness. The sourca geonatry correction factor is defined as G(E,1) = D(I,1) /D(E,=) i i whera D(Z,1) and D(I,=) are gamma, dosas at the origin of a henispherical cloud sourca for finita and infisi:a radii, respective $y. Values for G(I,1) based on poist-karnal integration over a hemispherical source voluna in air, asstasing Bergar's azpression for a dose buildup factor, are given in Raf.18 for various energies and sourca ::dli; values of G(I,1) are plot:ad is Tig. 4. Figura 5 gives fi 1:a cloud-geo=stry correction fac: ors fer a couple of gamma amargias of in:arest is this study, whera very lic:la difference is seen between 1 and 1.25 MaV gn= mas. Simulation of small and large shal:ar scrue:ures in this study assumes effec:ive hemispherical radii of 3.4 sad 10.3 s to represan: shaltar enclosures of approximately 400 and 3600 f: of floor area, respac:1vely. From Fig. 5, estimated small-and large-shelter-strue:ure-geomat:y correction fac: ors are 0.01 and 0.034, respec:1vely. These values are assumed is estimating the affac:1veness of shal:a: s::ue:ures. FALLotC CA.'e'A-50UR02 r" DTUAT:CN Considerabia analytical and experisantal work has been done :s decarmina the protection-against fallout-sourca gn==a radia: ion af forded by various types of building strue:ures, primarily for civil defense applications. Burson and P:sfio (17] reviaved such of -h work for application to cuclear power plan: acciden:s, and performed addi:ional calculations usi:3 the nached given is Raf.19 :s estimata a::anuation fac: ors for sona s1= ole rec: angular scrue:ures (713 6). Ixperi= ental resul:s (20-24] generally 1:dicata protection fac: ors (??), of:an i 2

. _ ~. 10 O 4 e a e e e e e, , e g ~ - N 9 0.3 N Effective Shelter Radius = 100 meters a.: w e 6 O au 4 0.2 -< r C a duS= ue6 L.6 20 0.1 - - 20 -7 10 1 0 O L 2 3 i Gama energy (.%i) Fig. 4--Finita cicuc, ga ma dose-ccrrection fac:Ors versus garma energy G ,m-. r a g. .m -,----wy-aur

21 s 1.0 j r i i i i i..i..,.... -..... i i ! I i.: i i i ;. I g l-1 -..l.' ..i i :.. wll i t ; i i .r.. 0.1 CC w g .u O 1 MeV ~ u, e C 3 1.25 MeV u 42 h 6 Cv 0.01 - l l a r t i i I 0.001 ~ c, - 1 10 100 Radius,R(::etars) Fig. 5--Finita cicud, gama dose-correction fac. ors versus effective sneltar radius

22 1.0 i 1 ) s i O M w< so u v< v w 0.1 Fleer seace (ft-) g J J g* 10 x 10 5 20 x 20 4 2 x 30 @ x 90 1arge ~ strucures small struc-tures 0.01 O 10 20 30 40 50 50 70 7 Mass thickness, x (gn/cm') Fig. 5--Geraa at:anuation for struc=res-fallout sourca 9 ese m. m. m M am, ne w w we 4 --c e - + - - - - y ,,----m -g_-----9 --T4

=. - 23 rafarred to as the reci,mcal-of-se:enuation factor, from 2 to 5 for a wood frama homa (without basement) and from 3 to 10 for block and brick homes. Most at:anuation-factor estimatas for fallout gamma sources in-ciuda the effect of ground roughnes's, which can vary accordingly as tabulated below by the Defensa Civil ? aparedness Agency (19]. Ground Roughness Condition Reduction Factor Smooth plane (hypothetical) 1.00 Paved. areas 1.00 to 0.35 Lawns 0.85 to 0.75 Grave 11ad araas 0.75 to 0.65 Ordinary plowed field 0.65 to 0.55 Deeply plowed fiald 0.55 to 0.47 Many ochar aspects affec: procac:1on against fallout sources, in-ciuding strue: ural sacerials, vall-axposure areas (taking into con-sideration basements and mul:11avel dwellings), topographical varia-tions (hillside or flat g cund level), mutual shielding offered by nearby build 1=gs and struc:ures, and the internal location within a j shel:ar structure. For example, protection factors for basementa may l be from 10 :o 50; and material shielding of nearby buildi.gs say effar procac: ion factors of from about 1.7 to 2.5 (25]. Complex strue: res such as mul:1 story offica and apar:sent bu1%gs offer procac: ion fac: ors of 20 or more (away from doors or wisdows); this, factor is. supported by experisantal sessurements (25-23]. Table 4 summarizes recommanded at:anuation or reduction fac: ors for some representative shaltar strue:ures and also v= W i== (17]. l The redue:1on valuas in Table 4 are relative to 1 secar above a hypothetical, uniform infisi:a plana of homogeneous sourca con-centrations. The values given are only representative and not to be takan as exac:; and as indicated above, diffarant values will resul: because of wide variations in construe:1onal details and topography. Ist1=atas of the extar:a1 '.3 dose from radictedi=e fallou insida a shal:ar structura are based on a dose detac:or pois: 1 =acar above =_- .. ~... - - . - ~. ..__.7, ,___,-,_,,v_,_.--

24 f Tabla 4 x RIPEZSINTAT17E EDUCTION TACTORS 70R. SURFACI SOURCI. Structure and/or Location Reduction Factors In above a hypothetical, ir.ftnica, smooth plane 1.00 la abcve orrHnary ground 0.70 la above cantar of 50-ft roadway half contaminaced 0.55 Cars, pickups, buses, and trucks on 30-ft road: Road fully conemminstad 0.5 Road fully decontaminatad. 0.25 Trains 0.A 1-and 1-story wood frame homes (no basament) 0.1 1 and 2-story block. or brick homas (no base =ent) 0.1a Hans basement-1 or 2 valls fully exposed: 0.l* L story, less than 1 ft of basement valls exposed 0.05" I story, lasa than 1 f t of basement valls exposed 0.02' 3-or 4-story structuras, 5000 to 10,000 f t per floot: First and second floors 0.05" Basament 0.01* kitiatory structuras, >10,000 f t per floor: Upper floors a 0.0L Basemene 0.005* ]

• Aaray from doors and windows.

i

,_ _ _ _ _ ~ i J 25 s-, g. - a circular area for small sad large shelter structures in which infinica-1 plana dose-conversion factors were used (see Table 1, p. 4). Therefore, s,fini:a-plane geoastry correction factor was applied in calculating dosages, defined as G' (R) = D(R)/D(=) where D(1) and D(=) are the finita plane (radius, R) and infini:a-plana doses for d = 1m above tha surface. G'(R) nay also be expressed as 1 - D(R,=)/D (0,=) where D(R,=) is the plane-sourca dose for source radial d1=ensions from 1 to =, and D(=) = D (0, ). The dose D(R) for a flat plane source is given by k B(ur) e'"# dr D(R) = 7 a S r 42 2 i where 5, = source strength per uni: area, A = dose-Conversion constant, R = distance from source plane (1 n), i = gazona-ray absorption coefficione in air, l 3(ar) = 1 - Care (3erger buildup fac:or). Integracing :he above over :he appropriate source-plane upper li=1:s (see Appendix A) yields kS (1-D)ukR,2 2 yR "".2 2 C a D(2) = . '1 " (1-0) 2 _g... e "h - ' - - - " - - - * ' ' - ~' - ' - - ~ ~ ~ " * ~ ~ ~ ~ ' " " ~~ ' ~~ ~~

26' g '1.(ud) + (1-0) e (1-D)W D(=) -

2. '

~ where ((x) is the first-order exponential integral fune:1on, and C an[ D are the Berger buildup factsr coefficiants for air given in Raf. 29. ~3 Assuming 1.293 x 10 sm/cm for air, calculations of C'(1) ver.: made for 0.5,1.0, and 2.0 MaV gamma. rays for various values of I using the ~ following data from Ref. 29. Energy (MeV) C D 0.5 1.6001 1.0094 0.088 1.0 1.1571. 0.05749 0.063 2.0 0.8363 0.0243 0.044 Some resul:s are given below for 1 = 10 and 3Cm: 'G' (R) I=ergy (MeV) l ICm 3Cm 0.5 0.413 0.620 1.0 0.414 0.624 2.0 0.419 0.622 As indicated above, very li::la varia:1ca exists fr:m 0.5 :s 2.0 MeV; the 1-MeV valcas plot:ed is Fig. 7 are assumed :o be represas:a-tive for this study. Agais, assu=:=g 3.4 and 10.3 s as effective radii applicable for small and large snel:ar s:ructures, yields fisi:e-sourca geometry correc:ica fac: ors of 0.23 and 0.43, respectively, which are used in he shal:ar =odel calcula:1:=s. = _... 1 i ._e 4 4,- -.--,..-,---m e w-

...... ~. _. _.._ .8 17 w a v r. t .t s 8 . 1I. . I.. I. 2 l { i 8 i L_ S p i 1 f a ~ u i e ~ bO ov 4 o m. 5 -a u = b b a - e 6 g e C u g ~ b. = as a 3 e a C - a a e m o 2

• ev6s 0

m o .e m. = .a I u,- e u n I i I j C1 + i u. e o. a. u. a w ~ c a o o (y)e *w.:e; uop=aaaog

t 2 15 TDE-FR&E MODEL The question of shelter protection effectiveness f;oa airborne radioactive material accidentally released, from a. nuciaar power plant. is dependent upon the time required for individuals to gain entry into

a. protective structure; and the length of time they remain, as compared vich the etas of cloud arrival and passage. The required entry time assumes that individuals are c sasferred from either unprotected or protected locations to another location affording==^= protection,

, considering logistic constraints, etc. On the other hand, individuals could also be located in houses and buildings already providisg adequate shelter so that effectiveness would not depend on access cine. Figure 8 shows cha time-frame model assumed in estimating the effectiveness of sheltering, as well as other times of interest (to put them in perspective). Measured from initiation of a possible incident, (T +T,) is the estimated time-of-arrival of the assumed lead g par-h of a radioactive cloud. The time from source release, T.y. measured from incident initiation, may vary from about 1.5 to 9 he for the more severe accident estegories (1}; although in one, instance (Ph'R 4 Category), a value of 23 hr was indicated. Source release cises of from 1.5 to 3 hr were considered to be of more isterest in this study, since protective evacuation actica night very well be = ore appropriate, considering the greater c1=e that would be available. Cloud arrival *.ime, T,, would depend completely on the location of a shelter from the point of release and the prevai!*mg meteorological conditions (primarily, vind speed and drection) during cloud travel time. Assuming a given sustained average vind speed (and direction), z/E ia an escisate of T,, where x is the distance from the relaase and E the average wind speed. For example, for an estimate of the average low-population zone distance of around 3.4 si based on siting data given for 76 nuclear power plant sites (30], cloud ar:1 val cise vould be approximately 1-1/2 hr to 20 mis for vind speeds of from 2 to 11 mph, respectively. The effective time for sheltering from incident initiation is shown is Tig. 3 as (Tf.), where TD 7*

• • ~

a ing event to the sheltering order, and T. is the actual c1=a spent in taking 4 ' ~ --p 4mm

~ i, l. i l f Ta*I T (or T,) = = = a 9

c.,

l l . y,..,,,c..

.. n.-

3 .ji* 4 * .r Tg+TT =

Time in shelter J..g;g p(it,j.

t i s3j ..,'.a .{t! 't' '1 'h,('. i f ;,e 8 qt.;.Tg.p'li-42..T,.. d; -Tr s.;, -T~ y l' . 'i,i.I),, J.Ns : t.? s /. j-4 :.. 3 t 't p . g 'I. O f / Tg - source release. time T2 = shelter time after cloud passage i incident I"ILIdlI"" t T = cloud arrival time T = evacuation time after leaving a y shelter i T, = cloyd passage time TD = delay time from initiating event fi to sheltering alert T = cloud-source release duration 5 (fort,1 T.T,=T) T = actual time spent taking shelter 3 3 y T = shelter entrance-delay time I after cloud arrival flg. 0--sheltering-model time-frame )

_., ~ i 30 .l 74 sheltar (assuming individuals are not already in a suitable shaltar). "4~ Delay tiaalastimates (T ) have been discused by the ZPA (31] with y y; > regard to evacuation that any be somewt.at applicable to shaltaring,. j' lsinct the time components of *g are similar or may in face be one and ~I the same ia carna of a local'dacision process. As assumed hara, Tg s represents the total. delay ti.:a from initiation of an event to onset a I of physical movement to a shelter. For evacuation, the EPA estimatas this delay time as being from 0.9 to 4.5 hr [31]. Also, for evacuation, the EPA estimate for T is from 0.2 co 1.5 hr, which may be azcassive 7 for shaltaring on.ha high end. That is, reasonable shal:aring :1=as may be anywhere from a few minutes to half an hour. Allowance is made in the time-frama modal for a shaltar-astranca dalay time measured from time of cloud arrival, which would be dependent upon T, T,, T, and T.. The shorter T is, the battar is the sheltar-y D ing effectiveness with the '=vd - advantage for 7 equal :s zero, 7 (I +T ) f, (T +T,). Normally, T would ha expec:ad to be at:har zero g 7 g g or small excepe for relatirely high sustained wind speeds and/or for loca-tions eslatively close to a release. The cloud passage ti=a, T,, would depend on sourca ralease duration (T ) and whd persistence ti=a (direction and speed). T may range s. s from 3.5 to 4 he, depending eti che accidental ralassa avents (1} that would be of intarast for seeking shel:ar. Esti=atas of vi=d persistance time should be based on particular sita meteorology. Is :er=s of ;ro-tactive actica by the public (i.e., taking shalter or evacuati=g), :he wind persistenea time ast.imatas sade at the time of and dur:. g pos:1= cide =: phases of an accident are among the most importan: para =atars affec:isg the effec:1veness of the protective action. Ideally, the most useful t7pe of information on persistence, when makd g protective accion decisions, would be an est. mate of the maan or expec:ad wisd-direction d persistence cine--given a particular :1== of the day and that z. particular '., direction has been maincat=ed up :o that poist. 'Such predic:ive abill:y 'would have to be formula:ed from a detailed statistical analysis of ,p '{" si:a meteorological data of record requiring frequent observations ) (perhaps every 15 sis) over an adequate period of c1=a. A =eans of 6 ,..,,.~ - --.. - - m

= ~'".-..J' m e==. o . ~. _ y . / 33 w f 4 computing source-cloud trajectory based on real-tima analysis of site h and regional matarological data. is dancribed as a feature of the ARAC i program currently being developed at the Lavranca livermore Laboratory (32]. This kind of capability would obviously be wary useful in pf==M emergency public actiona such as sheltering. In this study, the persistanca time is simply related to the. cloud exposura cima designated in Fig. 8 as T,; such that, if f is an estimata of the persistsaca time, than T, = T, for T,,$, r, otharvisa, T, = r. The tian-frama modal for shaltaring 'also considers the time that individuals may have remained in, a shaltar after passage of the radio-active cloud. For example, althcugh exiting a sheltar may afford more protac:1on and thus avoid exposure to accumulated intarsal con-tamination, precisa axiting with regard to cloud passaga may not bt practical, and the overall tima spent in a sheltar could be as *-d*ca-cad by the shaded portion of Fig. 8. This shaded portion, then, desig=atas an "incarnal receptor" with respect to radioactive gaseous fission-product sourcas. That is, during T, after cloud arrival, unprocactad t l individuals may be exposed to airbor=a radioactive material by means of direct %'B ganana radiation from both airbor=a and ground-sourca fallout material and from radioactive material encaring the body via f-hmistion. During the istarval insida che shaltar, (T +T,+T,) - (T +T ), the istar-g 3 nal receptor is exposed to k*B r=d*= + n from airbor:a and surfaca-sourca (fallout) material, both isside and outside the structure, and incarnal 5 radioactive material encaring the body via *,halacion. Dur1=g T ' 2 afcar cloud passage, the istarsal raceptor is assumed to undergo the same type of exposura vich the exception of that due to airborne gaseous fission products outside the strue:ura. Fisally, af:ar T, the tisa-f rama model makas allevanca for the 2 tisa that say be required for leaving the area (where an individual may be azposed to outside fallout is trans1: either on foot or by ( vehicle). If vehiclas are used for transport, sisulation can iscluda l the affect of shiald1=g at:asuation of ihe fallout-soures gm radia-I tics. In ta:=a of tha 1=e-frama modal, the shicid1=g aff ac:ive= ass i l 12 defi ed as the ratio of the fase received u= der unprocac:ad and ( ~ ~ ~ ~ n...'. ._..... ~... ' ~ ~ * ~~

I ~ 12 protected conditions to that received under unprotected conditions over the interval (T,+T +T ) due to the exposura modes mentioned above. g y The time-frama modal is thus. formulated. to indicata the effects of the time. paramatars on shaltar effectiveness. The affectiveness estiastas, in this study are mainly concerned with times commancing at cloud arrival, (T +T,), in which simple radioactive decay by each sourca g isotope is considered over (T +T,). Nota also that the time-frama g model assumas an abrupt boundary at both the leading and traillag edges of tha radioactive cloud material. Of course, in reality, this is not true, as it is well-knavn that turbulent diffusion in the atmosphere gives rise, on the average, to continuously changing airborne sourca boundaries--whose Mman=1onal scalas, havaver, ara such that the above model would be a reasonabla approximation, considering the sourca release incarvals of interest (axcluding an isstantaneous puff). DOSE RIDt:C" ION FAC"OR The estimated measura of effectiveness afforded by a shelter strue:ure--based on the modals and assumptions discussed above--is referrad to hara as the dose redue: ion fae:or (DEF). This value is given-by the ratio. of the dosaga received duri=g shaltar protec:ica to that which would be received in the open. DRF values are esti=ated for both thyroid and '.1 exposures. The DEF for ~='B ga=ma dose is given as EC + IC e ?D (DRF)y = EC

• C

+ FD e o o o where EC = External gamma airbor=e sourca dose, shal:ered, EC, = F.xternal gamma airborsa sour:a dose, unshal:ered, IC = I=halatien airbotte sour:a dose, shahered. IC, = Inhalacion airbor=e sourca dose, unshel:erad, FD = Ex:arnal gamma surface sour:a dose, shel:ered, FD, = Ex a::a1 ga=na surface sour:a dose, unshel:ared. The DRF for thyroid gland dose is given as mv-, y-----ww -m ,. -, -,,r,n,,,, -,,,, - -, - - ---

m- .t 33 l s s i TC (DET) Thyroid = TC Q where TC TWraid inhalation dose, sheltared, = TC, = Thyroid inhalation dose, unsheltered. c Table 5 sumarises the dose components given above, relating the source, receptor, and time-frame conditions that were considered in performing DRF calculations. For example, EC and FD values include esti=ates of externsi gamma '="5 dose for sources both inside and outside a shelter structure for the exposure times (defined in Fig. 8, p. 29) inditated. Shelter dose components (IC, FD, IC, and TC) also include a portion of unsheltered dose contributions accumulats,e aver the ex-posure period, 7, to simulate the effects of shelter-access delay times 7 that assume no ' protection during that interval. The remainder of this section desc-ibes the development of these dose components used in the calculation of the DRI values. Doses dovuvind from an accidental release of airborne gaseous fission products are dependent upon the concentration of the airborne radioactive nacerial that can be expressed as follows for continuous source release conditions: X(r,t) = (x(r)/h) h(c) (C1/m ) 3 where x(:)/h (sec/s ) is the ratio of the concentration x(r) (Ci/n ), 3 ~ at a distance from the release to the source release rata Q (C1/sec); and Q(c-x/U) (C1/sec) is the cine-dependent source-release rate function. In general, the dose at : is given by the integral of the concentration 1 over the period of exposure, T,, t u 1 7 D(r) = K x(r,t) de ran g O A f e 8 '. g w, ww e e eme ammuso emumme- - -p---- -w----+g---ev e w ww w- -.-e--r'" u-- - ' ' - - - - - -9m.-r-wd-* ww ,e d =ee-r-eek -ew-*-== g*Tw=e--w-w g-e----smm r-- u

34 f I Tabla 5 DOEI CCMPONENTS Dose Source Receptor Componenc In Out In Out I I T,T* 1 v EC, FD I I (r,-I ) + I

• t g

I I (T,-T ) + T2 g IC, IC 1 I I (T,-I ) + T t g EC,, FD, I I (T,+T +T ) 2 v IC, TI o o a.I, and T are post-outsida airborne cloud ti:nes and apply :o :.5a g ~ fallour dosa (TD) only. t Me-m e h a hmM hm =

35 4 4 where K is a dose conversion, factor. For this study, calculations t 3 I were performed assuming x(r)/Q unity (i.e., a unit dilution factor), s4 ca it is a cousson multiplier for all dose components and therefore i dcas not affect DEF valuaa. Accordingly, the dose. component as-dmatas described hara are based on integrations of the time-dependent sources both inside and outside the shaltar structura. The release rata at the source is assumed to be constant with a correction for simpla radio-activa decay over a release period. T,, fQ At ro Q(t) = a (C1/sec) 7 s where Q, is the initial radionuclida activity inventory in the re-actor at the cima of an accident (Tabla 1, p. 4), f, is the radio-nuclida ralaase fraction (DBA assumpticas), and 1 is the radioactive - decay c nstant. For ease of illustration, the davalepment of the following dose components does not use subscripts designating each radionuclida sourta, and it should be understood that sun = nations over radionuclida sourcas are performed in saking computations. The calculations are obta1=ad frca differential rate equations and intagration over the time-depardent sources. Derivation of these dote component relationships are detailed where nacassary in Appendix 3. l 00SI COM*0NINTS-UNSEL*"L" TID Whole-body cloud and thyroid dose components assuming :o shaltar procaction are given as l T .zC,- g- -A(T +T,) Q(t) de g IC K '3 e = o 2 0 .!C,, ,1 7 3 K l ..r .y_y_ r --_g ..y.-. ,,...,.,m,,,, 7-,-=

... i.. 36 g -- 1 +q- ) f e- -AT o E *1 (1-e e) ~ g 73, ran s .r n. 3 where r, x 'ad I3 *** th* **** = 'ar=1*= '*c:='= 51v'= far 'd" cla"d t 2 genea, 'JB inh =1= tion, and. tha thyroid inh =1= tion dose, respectively, and I is the broaching rate assumed to be 3.4 x 10 (m /sec). In the above, tha source relaase duration. T,, is assumed to be the devuvind exposure time, T,. The. local fallout deposition race outside the sheltar is assumed to be 73 (t,c) (C1/sec-s ), and the depletion. rate to be due to only radio-X active decay. Expressing the airborne concentration as x(r,c) = x, e-Ac, whera x, includes the exp [ r('g" +!,)] tern, the outside ground-fallout deposition, F(t) (Ci/a ), is obtained from tha following equation: dF(t) -Aa =Vx e - AF(t) dc 3, o Integrating, -At 2 F(t)out = 7 ^v te (Ci/s ) go The fallout dose co=ponent is given by integration'ef F(t) cut A* tima of cloud passage, T,, plus the contribution from the fallout source after cloud passage integrated over the reference ti=e, ( (7 'T )* 2 s "' T T,v?* -1t FD = K, F(t)ou: + F(T ) e de o e e ,0 0 1 l -AT -AT[ I, a -A(T,-TA: l =7 X K 1 - (AT,*l)

• 1-*

~ 3 4 A !*3 s Where K; is ths grounc-sourts gam =a-dose conversion factor. e

t E e 37 y + s DOfE COMPONEYrs-SHEL* IRED Airborne Source--Inside The source intake rata foc a. shelter structura is assumed. to be -A* tLx,a , where c is the ingress frac. ion (discussed above); and L (c1=a) is the air change rats that is (f/v), whars f is the volu-matric air-inflow race and v is the enclosure volues. The internal concentration C(c) is assumed to be reduced by air outflow, radioactiva decay, and incarnal radiciodina surface deposition at the rates given by (L+A) C(t) and (V'/1) C(t). For incarnal surfaca deposition, V' is 8 5 the depositics velocity inside the shelter (discussed above) and i is the mean falJ distance for iodine fallout satarial in the sheltar enclosura, assuned to be one-half the average floor-to-ceilinly distance or about 1.5 matars. The significance of this coefficient as compared vich (L+1) par hour can be seen from 7,h) = 0.00025 (m/see) x 3600 (see/hr) ~L = 0.6 hr g 1.5 (a) whera (as indicated above) a range of 0.125 to 3 hr for L was chosau for the DRI calculations, and A can rsage from about 0.0036 to 0.8 hr-1 for the radiciodines. Sinca v' = 0 for the rare gases, tha (V'/1) S 8 l coefficient is rare for datarzination of the internal noble-sas con-l centrations. Based on the above, the incarnal structura concantrations ~ -- are dater =ined from the is11owing differential equation: l dC(t), ,-At - I C(c) i de o where K=L+A+K, and K, = 7'/t 3 l l Istagrating, C(t) = a -e (C1/n ) = s

En I The dose ace.:mulated in the shelter scrue:ure over the ti=a in:erval (T,T,) is g T e D =. C 3 C(t) de 1. g[-C -C[, 1[-AT GK I "X L -1T,}) 7(a D o g 7 - 7(a -e (g -a ran Specific dose components are given. by the above equation, depending on the values of the dose conversion factor, K), the breachiss raca, 3, and. the fini:e cicud-geometry correc:1on fac:or, G, as listed below: l bl 3 l G gl 1 l <L EC7 lK2l3*4*10 lL IC1 TC K 3.4 x 10 1 t 3 1 Af ter the cloud has passed the vicinity of the structure, -he interal concentration is C' (c) - C(7,) e. g' and :he dose ace.:=ulated is the shel:ar due :o :he internal airborne source is ? 2. D=G B C'(c) d: O Cg3 -C, g C(7,) (1 - e

• )

rem = 4 g.g g,g hM m* ,,,%7 _,_-._,,...n_ r,_ w__-._

? 39 s sgL -AT, - C,> C(7,)

1.,f ca.

-a Iha dose components EC, IC, and TC are obtained in the manner given 2 g g aboveforEC,Ig,andTCp Dosages due to airborna gaseous fission-g produced sources inside the structura are given by (ICpEC ) + (IC +IC ) g g 2 for the WB and (TC +TC ) for the t!iyroid. g 2 Airborne Soures--Outside During the cima interval T, it is assumed that individuals are y unprotected and dose components are s4= dime to those given for unpro-tasted exposures over the exposure incarval to the cloud, T,, i.e., T' " ~( * -1("g+T,) f g* a .-L,1) IC' I5 (1 = e = rem o 2 TA a JC;. .% B. The attenuated WB gamma-ray exposure in -Je shelter st:ucture fr:m the outside at:barna cloud source over the internal (;g,T,) is given by 7* -At EC{ = A(1-G) (X, e dc T g A(1-G)kX / - AI 3 t -AI,\\ (a = -a rem g where A is the cloud gamma-ray actanuation, (1-G) is the source-gecnetry correction factor for the outside cloud, and x,-the refarenca concentra-tion per unic X/Q-is l . ~. ~ ~.. ....,.-._.._,--_._..,_,_..---_.-,..__d___.._,--_._.._..--. ..-c

~ r- . -c_

>z

...,->m- +r -1 \\ l M -A(T +T,) g ISro* X, * -t-Surfaca Source--Insida The differential aquation for the surface deposition rata for radio-iodina in the sheltar structura is dF(t) = V'C(t) - AF(t) dt 3 where C(t) is the internal concentration. Integrating the abova yields the fallout surface source, F(c)g, which is in turn integrated over the incarval (T T,) to ytali cha WB azternal gn=ma-dose component (see g Appendix B) given by V'G'ex LE -17 -lT ~ ~ FD y= g, (17 +1) e - (1T,+1) e 7 f(a-17 -17 \\*) + g g (/ -C, -C \\ f ~ a a -e ram After cloud passage, the 'n1 dose from incarnal radiciodine surface de-position that accumulated during cloud passaga is given by ~AE FDg = F(T,) g e de O 1 i -AT V'G'cx LI I e -17, I ~* = e -a 1-e ran E, A wet / 1where F(I,) g is the internal fallout lavel at 7. 4 eum mum o e e me d> m M A m. -m.

/ i <3 41 . s 1 Aftar cloud passage, internal radioindina fallout deposition con-tinues to taka place owing, to the residual airborna sourts inside the shaltar st.:ucture.. The rata of incarnal fallou-deposition is dF(t) = V,C(T ) e~Ke - AF(t) de g a Integrating the above ytalds the fallout deposi:1on from the post-cloud passage ista=al-airborna source in the shialding structura, which is in tu:n in:agratad to yiald tha WB dosa wri::an as (see Appendix 3) V'G'cx,LI -17, -KT -AT -C 4 y 1 ID -a 1-a = 1-a raa 3 g, \\a ) g,g \\ j g,g \\ ) ~ The W3 azzarnal samma dose fron ista:nal radiciodina fallout is the shal:ar structura is given by (TD +FD +FD ). y g 3 Surface Sour:a--Outside During tha ti=a istarval' T, the accumulated '43 desa whila saddsg shal:ar (unprocac:ad) from outside ground fallout deposi:1on is T1 FD* = K, F(t)out de o 0 VgK -AT "' g 1 - (AT *L) a ram = g y 1 During the ti=a i=:a: ral (T,7,), the WB gamma dosa inside the y l shal:ar strue:ura from outsida steund-fallout deposition is t l l 1 l t w-y.,e-,,-- e

42 Te FD ' = A' K. F(t)out dr. 1 + T L = 9 i ~17 -AT I i 1 e = A'V x,rg g (AT +1) e - (IT,+1) e g g ram where A' is the shaltar-structure attenuation of gssuna rays from the ground-fallout sourca. The WB gaansa dose accumulated insida from residual outside ground-fallout deposition is T2 FD ', = A' K4 T(T )out e de e 0 -17" 7 e 1T = A'7 x,K4 3 (1 - e ) rear Af ter T '. the time interval assu=ad durisg which people may conti:ua em 2 be is the shelter structure af ter outside cloud passage, che couputational model assumes chac individuals laava the vicisity of the sheltar over a cima 1statval, T, either unprotected (e.g., on foot) or protectad from y I residual ground-fallouc sourca ga=ma. radiation whila laaving the con-taminated area is a vehicle with a shielding attanuation factor of A,'. Accordingly, the WB gt m dose is 1 2* v TD ' = A'K, T('" )out -At 3 v+ e e de 2 D ~ T e - AT., -1 (~,+T [

• y

. A'y ^ g rem vgu4 A 6 .M. M w e- -,-7,pr.- g-_.---g, ,-w-- w-o- - ~ ~-,--,--- - - - -- e,. w .-w,--w r

i j 1 43 y 1 ") c r I f The external WB dose from shielded gassea radiation emanating from ground-fallout deposition outside the sheltar structure (with the exception FD', where the receptor is assumed outsida) is FD' + FD{ + FD{+TDj. Note that for FD[, FDj, a'nd FDj (receptor insida) a secastry factor--i.e., (1-C')-is not assumed, which is consistent with.he accanua-tion values, A', for ground-source fallout deposition. That is, the fallout source on the roof of a simpia structure would approximate the ground-fallout source deposition in totus of source-geometrical effects for tha reference dose point 1 meter above an idealized ground-plane source, (see sketch below). .:? v.erryvm.wim.'*.1u:-~~. r:.. Shelter structure Fallout with no O 5tructUrt .;m. : :.. s.;;.m - w..n n F

• ^* M~ W "A M ~ *
• lllllll1t lllllllillllllllll lllllllllllllllllllllllll1lllllllllllIllllllilllllllilllll 'Ilililit illllllllllllllllllll SHEL"I22iG AND EVAC"AT*0N An investigation was made to desarmine the utility of the combined protective action of sheltering and evacuation. That is, both from the standpoint of time constraises and the ::1F, the combined. protective-action measures may offer an advantage over sheltaring only. For exampla, for individuals located relatively close to the point of the accidental release is terms of either dis.ance or cloud-errival time, sheltari:3 may be the only option. Fur.hermora, if the duration of the sourca release were to continue longer than aspected because of, e.g.,

vind persistence or miscalculation, exit and evacuation from the sheltar structura say be advantageous is car =s of dose savd.=gs as opposed to ramm4-ing inside over the vnole cloud-passage time. the i=portant considerations in addrsssing this questi.sn are exit-c1=a from tha w-

r 44 shelter ::ue:ure, T, evacuation ':: anspor

1=e, T. and cloud exposure 5

s time, T,; and protac:fon. charac:eri.stics of the shal:er structura (see above) asd any evacuatier, vehide(s) that say be used f cm ::assporting people out of a radiocontami=ated area The analysts of the above situation is based on a si=ple =odel (Fig. 9) assuming ideal shal:ering conditions where bach shel:er-encrance delay :ime and residence time af ter cloud passage are zero (77 = 0, T2 = 0; see Fig. 8). Figura 9 is 'a plot of ace.=nulated dose as a func:1on of sheltar time up to che cloud passage :1=e, 7,, where :he dose im D. 3 Values D and D, are :o suggest possible accu =ulated dosagss for shal:er 1 exi: at T and evacuacion time !_. During the interval I;, the =odel 3 assumes that indiriduals are exposed to airbor:e and ground-fallout source radioactive sa:erial while in an evacuacion vehicle that offers some degree of procactica discussed belev. The decision is s1=plified to making a c:= pari. son of the est1= aced dose values. That is, for Dt < 3, exit f:cm the shel:er s::ue:ure and evacuacien vould be a serious 3 consideration; whereas, for D1 > D, it vould be = ore advas:4geous :s 3 ie=ais 1: side f :s the standpois: of dose say1=gs. An equivalen: =eans of deciding vce: hor :s effec shel:o exi: an:1 evacua: ion is based on DPS co=parisen. The ac:ual nu=erical approaca taken 1: :his analysis is based on the ques: ion of for vna: values of 'A'S, T, an:i ! is the rela:icnship (DM)S/s_ < (333). sa:isfiac, where s e a D (T,),,,' -" (DRF),. = D(_* e,cuc- (shel:e: only) s e and D('e)in 3('Se)in - 3('5T)ev (sfiel:a:' and (DES)S/?. = D(T )out avacua:1er.) e where g v. ,y _y -w_..,, ,.,y 9.- ....__.-w

O O .-.--.e+. o g og M h M e e O t t 43 O O b G F er - 0 e e 9 N en >= N \\ N,\\ = Q \\ >= ~ \\ g 5 ed D U U L. U 2 M 9 U A 3 M E. b .Ua span M AW I e 6. s. e-I t i N A -e O O C asca ~

e .,u t J t f -44 l' D(T )ouc = dose outsida shal:ar s::uctura, e D (T,)g. = dose insida shal:ar structure, i D(T,7 )in = dose inside shal:ar scrue:ure over in:arial 5 a (T,-7 ), 3 D(T,T.,.)av = dosa ace.mulated dur1=g evacuacion over is arral 5 g commanc1=g at 7.. a Assuming an evacuation vehicle, 3urson and ?:otio (17] as:1=ated that steel, and glass is aut==obilas and small cructs correspond :s an 9 average of roughly 2 gm/ca' of shield 1=g : hick =ess for ga==a radia:1on from an airborna cloud sourca. 7::= Fig. 3 (p.17), this thick = ass corresponds to an at: anna:ics of only abouc 0.95 (the value assumed is this analysis). For heavier veniclas (e.g., large c==ar:141 buses), tha gn==a at:anuation may be 0.3 to 0.9-sm ' not appreciabla. Also, assum1=g an effective vehicla acciosura radius of around 1 nacar gives a source-gecmatry corrac:1on fae:or of around 0.003 (Fig. 3, p. 21) for the conta=1:a:ad airborna =acerial is the vehicia. Gamma ray atta=uation is au::=obiles and small ::uck.s is 3.3 f : concaminated 50-f:-vida cads (Tabla 4, p. 24). 7alues esc 1= aced by Burson, based on arperi=an:a1 =easurauan:s (33} vera from 0.3 :o 0.67. An average valua of 0.6 was assu=ad in his analysis. Air ehmnge : stas for au:: mobiles under various c:ndi:1:ns of opera-tion have been datar=1:ed by ?acarson and Sabersky (34]. nel: :asui:s (713 10) are f::= seasure=ac:s =ade of pollu:ss:s,(0, CO, No, and N0 ) 3 7 inside a stock Chevrolac aut:=obile vi h an at:-c:ndi:icning ::u.:. he exchange rata is relatively high. In fac, :he passa=ge ::=: art =e== is not 1standed to be at :13h:; and even 1: te -=

• us air-c=nci:icn1=g mode, a small fan draws outside air is:o te c:mpart=ent. "i:tou: : is ventilati:n, the ratas can pr bably be reduced by a fac:o of f vi:heu:

difficul:7 The sisgle pois: =arkad by as at::v (Fig. 10) was :aken when, vi:h vi devs closed, :he vehicle's air condi:icning was turned off bu: the angina laf: :::=1:3 Cida: :hase c =di:1:ns, a fan also draws i: .e e d M. W6g me W

• G h

a ee m e e m e m

• N e

e e e aeem os 4.me ,.,,,.,-t ,=**6MSN'-.,,,._w- -.m-., ..m A_.%,

• '*#,-n_,.,,m,.,,,

n.g,,m e,..w, ---.-.m- _.-.-n,.

, i .f:l. it 1' .I ! l~ l .e lI'

e 1-il-

• ,I l

r

I.

.I D y 0 r / 9 s / tnem 0 t i / 8 r apmo l / c e r 0 e r / 7 g ne ss j / 0 e ap d r y 6 so l m c a 1 / ~ ) n h ni i x p m a ( i 0 sr 7 5 e t a d e a e rt p a / s n ot i e e t s l 0 c a / 4 rs i ti he l V ig f n W ni in o 0 di 3 nt / ai d en go / nc a hr ci 0 xa / 2 e r n re o ih t Aw / mg n Ci 0 /n 1 0 A' u s / 1 o r g n_ i F / /: / 0 0 8 6 4 2 1 0 0 0 0 y.Na. >D 3 ~ 0 0 0 0 0 0 6 5 4 3 2 1 _'*O >D tj. l l ..j,I l3 v tl,, 'l !, r ; '

m-e m. + * * * * * *

• 48 f

on= side air. At higher speeds ar.d vich the same settings, Q/V (air change race) would be expected to approach the values obtained vi-h the air-ccr.ditioning uni: in operacion. TIis expec:ation is based on :he assurgeton that general leakage ra:her than the fan is the dominant factor determining f/v a: these speeds. A value of 0.3 sia-1 (20 hr-1) vas chosen for thi.s analysis, which corresponds to M5 sph when general leak. age is :he demisaac fa.::or for f/v. Fenecra:1en of gaseous fission produe:s isto evacuation vehicles was assumed to be 100 percent for the rare gases and 30 percen: for radioicdines, which eerresponds :o the upper lisi: of the as:1=ates of Megav (12] based on si=ple shal:er s: ue:ura experi=ects. For shel:aring, the DRF and dose component rela:1cuships are as given above (p. 2Sf f.); where, for D(7,7,)g above, T =T and 72 = 0. Tor 3 3 y evacuation, the vehicle is assumed to be analogous :o a shti:ar structure, and dose esti=ates for 3(T.T.),y for the exposure-evacuatien :i=s, T., 3 are based on :he same dose componen:s considered for shel:ars-vi:h :he exception of radiciodine deposi:1:n inside the vehicle, which is assumed to be insignificant and, =oreover, ca= o: be nodaled ac:urately vi:hou: so=e experi= ental verifica:1ca. Ex:ernal *.B cicud-dese accu =ula:i:n fr:s ga==a-ray penetra:1ce. of the evacua:ica vehicle is T 2 T. I -it TC = A (1-G ) x e .dt out v v o !5 -17 3 -i!.

• 2-1-a

= A (1-G )K.x e v v 4 o A rem where A, is the vehicle a::enua:1:n for c1:ud-scur:e ga==a radia:ica, C the fici:a. cicud.-source geccer:/ fac:=r, and K, :he dose c:nversica y factor. Inside the evacua:ien vehicle, the rata of concen::a:1:n :hange is g ene M o geome~ h. " -- -

.. ~. 49 i 'l ? dC( ) = cx L -At e - I C(t) de ov v where I, = L + 1. Incagrac1=g the above for C(0) = 0 gives . -I *- C(c) = cx, (e-At (C1/n.3) v e for de concentracion in the vehicle. The dose ace $ulacad in the vehinia over the period T., is given as 7 +T.,. S D,, = G,cxh C(c) d: 'S ~ -17 -AT -K T 1 = G cx 31L e 1-e. 1-a re= v o a 4 Kv Specific dose conponen:s art obtained based en de values is: ce c:cs:snes as given bel v: g 3 K, in . l EC K, 1 <1 -s IC,n 3.4 x 10 1 TC,= lK l3.4x10' l 1 2 _t. Se ground-fslicu: deposi:icn 3.ven a':cve is T(:) u,., = 7 x : e '. go ~he ex:ernal a3 dose f::n g :und-fallou: source gn=a-rsy ;ene:r2-1:n of :he venicle during evacuatien is

30 ~M s7 A'K, F(:)ou: d: FD = ou: V

• 73 A*'V y K,

-17' -1(7 +T.)* (AT ?l) e = (17 + !,+1) a ram 3 3 1 The dose accu =ula:ad during evacua:1on, D(T.T )ev, cc :espeeds :o S either tha *,13 or thyroid. For :he

• d, che dose is (IC,s*IC

-IC 73cu:); ou: for tha thyroid.-TC No:a that is:a:nal exposuras for IC a:d *C ara g. g g assumed :o accrue only when the evacuation vesicia 'is i: :he vd..:1=1:7 of the airho:na radioactive gasecus =a:arial o"== :he perici T_, which is a very scod approx 1=ati:n consideri=g the large values of L. Tha: is, V is ac:ual':7 once.he vehicle laaves :he vizi:1:7 of.he airbor a radi:- active =atarial, x, is the differen:ial equatics above is :ero and :he is:eenal vehicia conce== a:1on drops very rapidly vi:his a fav =icutes-which would not give rise to any sig:1fi:a=: dosage as ::= pared vi:h c:n-di:icns when the vehicia is assu=ed to be is :he vici:1:7 of :he at:bar.e radioac:ive acerial, providad of ecurse T., is = ore ::an a f av 1=u:es. That is, tha equilibrius c: ce=::a:icn :..a: vould be reac=ed i :he vehicle vi:his a faw =1 u:as is given as -A: 1: cx.u e ex e ov s C = = cx e

• A 4

o eq v , -Lv ~ which would be approx 1=a:aly : hat outsida :ha vehicle. hen, af:a eav.ng the vi-d d:7 of at:bor e ::n:asinati:n, :he.:encen:rsti n of gaseous radi:- s ac:1ve matarial in :he vehi:la falls off as exp(-(L -1):!, whera *,y is y . %.5 sin-l (20 hr 1). i t gm 3.ee>wa-@ ee -W= --,,y y w-r%p-wer-w---7 w w mw w -my m-y y y a-w- ~ - w. -ery -wyy w---ww yyw-w-,

b 51 III. RESUITS ?scinatas of shel:er effec:1veness have been made us1=g the ORF calcula:1onal model and assumptions discussed in Sec. II. It is, of course, impossible withis the scope of -J11s effor: :o develop informa-tion ecmprehensive e=ough to anticipace what might be expected for all prac:1 cal si::acions. f.ccordingly, assu=pcions are made regard 1=g inpu: para =eters and tanges of variables is order 1) to de=enstra:e the degree of shel:e: effec.1veness in a general sense, and 2) to indicate sensi:1vi:7 varia: ices for some specific si:ua:1cus. I:put values used in de shel:aring calculations fall under :vo c.i:egories. Firs:, a set of fixed parame:ers were selected (su==arized is Table 6). B ase values are is par: based on stud 3 grou=d rules (DBA gaseous-release asst..ptions), review and analysis of existing da:.a. a=d a= at:e:pt to develop represen:ative inforsation : hat can also be-relatad :o the asceter' Scis j Se:dj (1]. S e co:1on of "f1=ed para-meters" obviously applies culy to this particular analysis; is reali:y, there =ay be appreciable vsriatier.s is shel:er characteris:ics and, for exa=ple, iodine deposi:1:n veloci:y. The second input catego:f consists of the ce= poral and vencila: ice ra:e variables selected :o isdica:e :he sensi:ivi:7 and degree of shel:ering effec:1veness over thei: range of values. Is some cases, ex::apolatica car. be made (vid care) to estisa:e shel:a effectiveness beyond de specif1: ra=ge 11=i:s used '- -='d g :he calcula-dens. Shel:e: effec:iveness resul:s are ;iven 1: :e:=s of :he 3?J i: Figs. 21 :h : ugh 31. Inough da:a are given 1: Tigs. 11 2:: ugh 31 :o ~ enable a fair a=ount of c: css-plot ex::a:cls:1:n. All :he :ise variables have uni:s of hours and are identified in Fig. 3 (p. 29).

• he ven:112-

_t

ion race, i is in uni:s of 5: ; and 55 and

• .5 designa e the s=al' and

~ large shel:er s:::c:ure ca:agories, respec:ively. The plot:ed :ssul:s in Figs. l'. :h::ugn 31 are discussec below. Figure 11 gives W '.,RI as a func:1:n of :i=e (!,) in the shel:e: scrue:ure af:e passage of :he airborne cloud scurce, ass" d g to delay (7,=0) 1: shel:e ac:ess af:e ini:ial cicud a:-ival and 1-h: :1:ud

• * * ~ =

.wm ~ ~ ~~

e i 52 Tabla 6 FIZZ 3 7AAA.C SLT.ARY u SCUICI T!2'E3 Eclease Ti== 3alease Duracien Case I, Hr T, Hr R 3 A 1.5 0.5 3' 2.0 1.0 C 2.5 3.0 CASECUS FISSICN PRODUC 3 Release I= grass Fraction 7:setice K: and Xa 1.0 1.0 I 0.25 0.51 SHC.TIRS S=all Lar;a St uetures ISS) St *:c:ures (LS) Cloud gn==a a::anua:ica, A 0.5 (0.6, 0.9)* 0.1 (0.05, 0.2)

• Falleu: zz==a at:enua:10, A' O.2 0.0L Fici:a cicud fac:c:, G 0.0L 0.034 Fi=1:a falleu: fac:ct, C' O.13 0.43 CE?cSI-'ON 7 (ou:sida) = 0.005 =/sec 7'(1: side) 0.00025 =/sec

= K

1. 7ariations ee

= =. - p. m. mg f"- $T -.-r -Te"'"'7

i I. i 53 0.5 i i _A i 3 g u ~ 7 lSS L = 1.0 t 0.4 n 3 C SS L = 0.125 0.3 - w =m l 0.2'- C _- 3, n 1 LS L = 1.0 / 0.1' [ C A53 LS L = 0.125 l i I i i O' O 0.2 3.4 0.5 0.8 1.0 1.2 3 (' curs) 7 n ?!.11--W3 ;RF versus 7 ' ('I "0'I "1) 9 2 I a mn_ m n w

f 54 N

• travel. time, (T,=1) f:ca the point of sourca release. Significantly, more procastion is afforded by the large shel:er struc:urs (13) :han the small one. (SS). The effect of ventilation rata is also mora 1::r-portant for the LS than the S3, primarily because of the d1*faranca is cloud-gam a attanuacion. That iz, a larger portion of :he dose in the SS is dua to gama ray penetration of the shelter from the ou: side airborne cloud senr e than in the LS; that portion of ths dose does soc depend

.L en the air changa rata. A value of,L = 1 hr may be somewhat repre- -L sentative, whereas 0.125 hr representa a fairly low value associated with a relatively cight structura vi:h very lit:la or :o forced air circulation. The relative pos1:1ons of the A, 3, and C ca:egories of release duration are also datarmi=ed by :he cembi=acien of cloud-ga==a at:anuatica and ventila:1on ra:e. For :he SS, da relatively larger dose componene fr:n outsida cloud-ga=ma ray penetration is sufficient :o offset the dose component fron incarnal airbor=a radioac:1va =acerial. For example, for T.2 = 0 and L = 1, de relative posi:icus of A, 3, and C ara che same for both SS and LS; buc de spread is larger for the LS than the SS, indica:1=g the effec: of a relatively lar ar nu=ber of air changas with respec: to delease duration (0.3,1, a=d 3 for A, 3, and C, respec.1vely) for the LS as compared vid :he SS. he c :ssover poi== at 72 = 0.1 for :he SS is due :o de 1:creasi g imper:a:ca of de ou:- side g cund-fallout dose ec=ponan:, asau=ed to be reduced at a ra:a dependent upon only radioac:1ve decay, as c=mpared wi:h the dosa f::= insida at:bar=a radioactive sacerial assumed to be reduced a: l a ra:a dependas: upon radioac:1ve decay, ventilation, and inte=al fallout deposition of :he radiciodi:ss. For low air-changs ra:es (*.=0.125 h ') 'i the CRI for :he SS is dete=ined largely f::= ex:e::a1 sources, where the A, 3, and C cu re posi:1cus primarily reflec: :he differences i: rad 34ac.1ve sourca decay. For the LS, da dose cc:rt.onents f::= curside sourcas ara relatively less impor: ant dan : hose for de SS; and a clear separation of de A, 5, and C release-duracion categories is not seen when both insida and ou: side dese ::=:eces:s are rela:1vely mora c==paraole. -e. M +46 ogme e e_ O

s I t. .55 Figure 12 gives DP.7 plots for the thyroid for the same condi:1ons assumed for Tig.11,. which apply to both SS and LS. Is general, the-DEF values indicata somavhat mors protec 1on for de thyroid chan for the 'n*R, and are more sensitive to,; particularly for L = 1 hr-1, 6. sines care are no competing ou: side-source dose composan:s. The ralative posi:1ons for A, 3, and C are due :o che differan: =u=her of air changes associa:ad vid each sour:ka release dura: ion. Si=ce da DEF values in Tig.11 correspond to a radiciod1== ingress frac:1on of 0.51, they scala accordingly. Calculated resul:s of de 'a'd CRF sensi:171:7 vid cloud-sourca a: rival ti== ara given in Figs. 13 drough 16. Tha ORT varia:1ons for tha thyroid, not plotted here, are insignificas: as a function of clou'd at:1 val ti=s, ;. In Tig.16, the ORF decreasa vid 7, for the 35 is due :s the relacirely decreas1=g impor:ance of -he bd-dose c =ponen: f::a.ha outside airbor:e cloud sour:e. That is,. de model includes only s1=ple radioac.1ve decay and predic:s -ha: da rela:1ve con::1bu-tion of tha nobla-gas sources :o da

• ='3 dose decreases = ore w1:h :1:e than does tha: :f the radicted1=es. I: reali:y, es: dec:asse vid a

say no: be qui:a as prevelant, particularly for :i=es longer dan a i few hours. The c=untareff act, however, is indica:ad fo: :he L3, si=ca che sig=141:a=ce of tha ex:ar. 21 gn=na "a'3-dosa c = pones: f::s the outsida airborne sourca is maskad by the graa:e ga==a-shielding atta=ua: ion assigned to da LS as c:=parad wi:h the SS. The rela:1*re positicus of the A, 3, and 0 curves are, as i= dica:ed above, due :o de increasi:g nu=ber of air changes, respec:1vely, during cloud passage. Tigure ll. shcws 'J3 ORI as a func: ion of 7 for case A, assn *d g a la:a shel:a ac: ass (7.=0.25) couplad vid n:anded reside =cs :i== A (7,=0.5) altar passage of :he airbor:e cloud. Ideal shel: : :d'd :g 6 (T.=0, T.,=0) is also shown for ec=parison :o indica:e :he sig=ificas: loss of prote:: ion for sen-ideal shel:e -ac: ass :d-d g. Figura 11 also shows loss of i=heren: L3 pro:ac: ion advan: age (due :s shialding), as

spared vi:h the 53, because of shel:ar-i=ing :ensiders:1ons.

...-- - - - ~. -

36 0.3 I l l C 9 V1 t i L. -~. L = 1.0 0.2 w E 0.2 -g -g A L 0,zgg l o l r l I l' + I l I i t 0 0 O.2 0.4 0.a. 0.3 2.0 l., '2 (hcurg) II 12.~ Thy W ~ RF versyg 7 ' I_',*O,7 et.<j 9 2 g s O i*- ~ -"~~~l'-#

~...... _. ? 57 0.5 (m i ~ 33 1 0.4 - C 3 0.3 A w=a 0.2 -c LS 3 F i n 0.1r-0 0 1 2 3 4 5 5 7 8 9 l 7a (hours) i Fig.13--W3 RF versus T, (T =0.T.,=0), L = 1 a 1 I

e 58 1.0 l l. l e t j .L_ 0.8 T =r 0.25 T = 0.5 1 g - S3 T = 0.25. T2

• 0*!

g 0.5-d w E

0. 4 -

~ '1

• 0 ' T
• O 2

Sa 0.2 - T=0,7=0 g 2 . LS i t t 0 O 1 2 3 4 3 3 7 8 3 i T (heurs) a I i l Fig.14..WB ORF versus T ' C288 A' (I *0'T '0) * (T =0.25,7 '0'3)' ' ' 1 a 1 1 1 2 i i i i t

4 s. ) 59 0.5-r t I T 0,25_

• T = 0,5 y,

s. y , SS i ~

0. 5' -

T = 0.25. 7 = 0.5 1 2 Ls

0. 4' -

t '1 ' O T*0 e 2 .e.3 wa: 0.3 - o 0.2 T=0,T2=0 g 0.1 - I i. t 0 O 1 2 3 4 5 6 7 a 3 T, (hours) Fig. 15--W3 CRF versus T, case 3, l'.=0,7,=0), (T.=0.25,7 '0'5)' L

• I a

u 2 _Ne-.e .m gg am .mm

e M s

0. 5 I

i i t l 1 O*b M W T

• 0. 25
• T = 05 1

~ s i 53 N T'

• 0 ' I = 0 0.4 2

- 53 ISE 0.3 T = 0.25, T = 0.5 _ L3 g 0.2 T=0,T* 1 2 LS 0.1 - i l t 0 O 1 2 3 4 5 6 7 3 9 Ta (heurs) Fi g. 15--W3 GRF versus T, case C, (T, =0,T,=0), (7, =0.25,T.,=0.5), L = 1 a q q y ,_,,..g 9m.y

---

.---e-m--4

=-

_.t.. 61 e Figures 13 and 16 are similar plots fo: cases 3 and C. respec:1vely, whera timing (T and T ) is relatively less important, because of 2 loeger exposure to the cloud source. Calculated DU resul:s in Figs.17 through 22 shw the effects of shel:ar-structure ventilation rata. Figura 17 gives the '4B ORF as a function of air change raca, L hr, for ideal shal:ar ed***g (7 -0, 3 T =0). For L less about one air change per hour, the 53 37 is based g on a relatively larger extarsal gama-does centribution from the out-sida airbo:se cloud source; for L greater than abnc one air cha=ge per hour, de ORF is based on a relatively largsr dose c =ponen: from internal airbor=a radioactive matarial. The LS ORF, on the other ha=d, is based pri=arily on tha relatively larger '43-dose couponen: fr m incarnal a1: hor =a gaseous radioactive sour:ss for all values of air change rata L. Figura 18 gives the thyroid DEI dependance on the ventila:1on rata for ideal shelter :d d 3 Coupared vi-h tha WB 3RF values is Tig. 17, t the thy cid DRE func:1ccal dependanca on L is much more pronou=ced, since the dyroid dose is based solely on internal airborne radioicdice. The advaccage of low air-change races less than about one-half per hour is qui:a apparent for procaction a;ai=s: ishala: ion doses. Figures 19 through 22 show the conparative effec:s of ideal and :en-ideal shal:a: :d 4 g. Figure 19 gives

• ='B UK7 values as a func:1:n of L

{ for case A, showing considerabia overlap of SS and L3 procac:i:= for ideal (7 =0, T -0) and sonideal (T =0.25, T =0.5) shel:er :d-d g, 1 2 2 l respectively. Figure 20 gives WB DRT for case 3 as a function of L when de 53 and LS overlap is much less :han is case A (71g.19), and Fig. 21 shows no SS and LS ove:1.2p for de longer sour:s release dura:1o= :acagory (C) wnen :he i=herent L5 protec:1on advan: age over :he $3 is saistai ed, even for sonideal shel:er :d d g. Figure 22 gives plo:s of the :hyroid 3RF, comparing the effects of socideal and ideal shel:a :ining. The inversion in de orda: of :he A, 3, and C release-duraci:n ca:agoiias !c: conidaal shel:a: d 4 g is pri=ard_17 due :o : e f:sc: ion of :i=e in i individual is assu=ed :o remais unproca--=d d-d g cicud passage for shal:ar-ac:ess delay :i=a, T ; i.e., the frac:1on of :i=e an individual 3_ is u=proeac:ed is larger fc A :han fc C. 2 .,n ~

.m m 62. 0.5... I I C _~ i 55 0.L - 0.3 w2 0.2-LS 3 A 1 0.1 1 .i + 0 O 1 2 3 4 L(hours"9) .1.17--WB ORF vers s L. (7,=0,7 '0'I "1)

9 2

a 9 4-e e w "F

63 s 0*3 I i' I 0.4 C 3 0.3 u E cm A

0. 2 -

0.1.'- - / l / i I i 0 O 1 2 3 4 L (heurs*1) Fig. 13--Thyroid ;RF versus L. (.g=3. '2"3'~'a'1)

~.-.. __-. 64 1.0c- -....... 4 ...i.-._-. s g r i T = 0'.25. T = 0.5 0.8 2 -5s ... - - ? T = 0. o c ' ' 2 = 0 * :* 1 L3 r 0.6 1 u.g T = 0. T, = 0 _ 33 1 0.4~ l G.2.

• =0 T =0, '2

- LS i i 0 0 1 2 3 4 L (hours'1) i "f 13--WB CRN versus L. case A, (7 =0.7 =0)' 9 'T.0 'x '0*-)' 'a

• 1 t 1

2 1 2 l l

• • ~

- - - - - ~ ~. _.. I J

65 e 1.0 .g.e a. i 4 ,r i I t i l i 0.8 . 0.'S, T, = 0.5 ,3 7 0.5 - 3 7, = 0. T, = 5 m tf sd . 0.25 i '1 = 0**5 0.4 T g =0 -u

0. 2 o, 't

,,4 0 O 1 2 3 4 L (hours.t) rig. cg-.,.. ,g-ve rs us '.. ca s a 3, (., =0.. 2*' ) ' (~' 1'0' '* c ~- ' l' 'a * ' es -'*2

s... _.

==._..._..__... t 66 . 0.6 l-I I , c.15. T = 0.5 ,SS 2 T g 0.5 =0 70,T1 - -- $3 0.4 . 0.15 ' 2 0.3c-I U l e c =0 .0*T2 -g T 1 0.2 - 0.1 - 0 O l 2 3 4 L (haurs~1) Fig. 21--WB 3RF versus L :asa 0, (T.=0,7.,=0), (7, =0.25,7 =0.5), T 1 = 2 1 e e e See e q w _ e-m- e o r y --, m g g r~ y

---

,--,--es--g

---~r-w

67 ~ 1.0 ....l.... l.. = L c i g t s c. 7 = 0. 25 ', T = 0. 5 1 2 0.8 - o r A 4

0. o..

6g 3 C 0.4 C 3 A .I 1 0.2 ~ . 1=0,..I = 0 i f P* k M. e 0' O 1 2 3 4 L (heurs~~) Fi g. 22--Tayroi c lAf ve.~.us '., (T. =0,T.,=0), (T =0.25,7,=0. 5), T 1 = i a ,_ _ w -

68 1 1 Figures 23 through 25 show WB 'and thyroid DRE values i= terms of 1*L and L in parametric perspective. WB ORT values are shown in Fig. 23 for case 3.and for LS. DRY values for T L (also the cloud passags = g time for case 3) can exceed unity for the larger values of L; this si:uation corresponds to encartsg a sheltar af:ar cloud passage, which gives rise to addizional dose from lingering internal contamisation ~ for T2 > 0,.21though the relative loss in shel:ar procac:1on as a function of 7 is insipificant for all valuks of 7 and L.

Also, 3

1 calculations perfor=ad during this study indicata virtually no procac:ive advan= age is seeking shal:ar af:a unprotec:ad exposura :o a pass 1=g radioac:1ve cloud. Figura 24 is essentially the sa=a para =ecric perspec:ive plot as Fig. 23 for the SS. Figure 25 gites corresponding plots of the DRF for thyroid, indicating considerable overlap for cartain para =ete: combinations of shal:ar-access delay time 7, and air change race, L. 7 Figures 25 and 27 indicata the effec:s of shal:ar-strue:ura at:anua-tion of ga:na radiation from :he outsida airborne radioactive cloud h: the SS and LS, respec:1vely. Figures 25 a:d 27 centain plots of the WB 3R7 for 1:dependen variations of :he cicud ga=ma attenua:1on, A. In prac:1ca, such variations vould not necessarily be independent of :he shal:ar-structura at:enuation of ground-fallou ga=ma radiation, as nor ally some correlation would La expec:ad. ~he results in Fig. 26 indicata, however, char a factor-of-two increase in ga=ma a::enuation resul:s is about an 30-per:an: i= crease is shal:er protec: ion for :he SS, whereas a fac:or-of-two redue: ion is the air change rate (1 to 1 4 at: ch:nges per hour) results in about only an S-percent increase is shel:a: procac: ion. Is the LS, :he effac: of cloud ga==a at:anuation is so; as significa=:. Resul:s is 713 27 indica:a that a fac:or'-of-two incrassa is cloud gamma at:enuation results in a f0-per: ant i= crease in shel:ar p ccactice, whereas a fac:c -of-two reduction is air change rata (1 to 1 air changes per hour) gives rise :o a 20-perca== incressa in shal:er pro: action. 6 - er em ewe ed.--meneum.we

=

ememe m e. e y w M v=-y W v p -r r-i 9 4-y w gg.w

---

y w----v---w--

w-T- ---,wwyw-wc'-y y y-y-sy-w-

- :=___..-_ 7. '2 *;- *E est: I snsaar gy: 26.--EZ *S;j (sancy) 21 21 0*i E*0 9'O t*0 2*0 0 0 1 .c,. C.

g J

0 l } C.I r I "Z 0 'ct 1=ct<....C \\:c 152 0<) ~ C*I j t'.O i <0t i .,,sc. 0 I [05*0-{S*O -10 E CT - '3 m 0t W 52I. 'O e 5L'0'lb? a 8'O 0t 52T*0 l a[;cI 0*I 0*T 1 a h__.. 7. _.l 1 I _,i I l l'. .l'. 4 zt 4 69 i 4 ' ' ~ ~

t 70 1 \\ 4 1.2 l I . L.4 _7 r t 3.0 1.0 0.9 1.0 1- 'O.125 3.0 E 'O E5 0.75 0.125 0.3 ~ - 3.0 ' I i3' 5,'5 O.50 0.125 - 3.0 '; '= 0.5 - 1 04 c 0.125)( . >..c. .v.s 3.0 m I 1.0 l

0. 4 '--

0. s-l> 0 O.125e) 'l

0. 2 -

~ 0 O 0.2 0.4 0.5 0.3 1.0 1.2 T.,(hours) Fi g. 24-WB CRF versus 7 ' **** I' 33' I

• I 2

a 9

i i 71 ~ 2.0 e i l 9 'L T. l l i 3.0 i j.9 h1.0 1.0 t

- o..125 1

7 } 3.0 0 0 0.5..... 1 c.. ,5 r 3.0 0.25 0.125' O.5 1.0 0.25 g 3.0 0

0. 5 0.25 0.125 0.25 1.0 0

0.5 0 0.1 - 0.125 0 l 1 4 0.02' 0 0.2 0.4 0.6 0.3 1.0 1.2 1.4 I Fig. 25--Thyroid CRF versus T, case 3, 7 1 = g a l t l h ew+. ,,qs. em 4e e-e e's e > .h

72 a e 1.0g, - t: + i. I l j 6 i 0.3 e i L A 2.0 0.9 0.5 1.0 0.9 0.125 0.9 w5 2.0 0.5 - 1.0 0.5 F 07 2.0 0.4 ,7 0.125 0.5 1.0 0.4 i_- 0.125 0.?

0. 2 -

1 -.g i. r i, 0-. i f O 0.2 0.4 0.5 0.3 1.0 1.2 Tg(hours) Fig. 25--WB ORF versus 7, case 3, SS U=0.4,0.5,0.3,L=0.125,1.0,2.0) 2 a 1 ,,y,, ,-e y v

73 0.20 t I t t g -i .L A 1

2. 0 0.2

- 1.0 0.2 2.0 0.1 0.20 - 2.0 0.05 - 1.0 0.1 w 5 1.0 0.05 l O.125 0.2. 0.10'r -+ i 0.125 0.1 0.125 0.05 I i i t e i i i i l I l l j l .i i , r C' 0 0.2 0.4 0.5 0.3 1.0 1.2 T2 (hours) Fi g. 27--WB ;RF vertus 7, case 3. LS (A=0.05,0.1.0.2,L=0.125,1.0,2.0) 2 .. r . ~ - - - -. -.. -

74 t Figuras 23 and 29 are plo:s of chalter DRF as a fune:1:n of shal:ar- -dalay access ':1me, T, for the 'dB and thyroid, respectively. Figure 28 g plots a:s given for a range of 0.5 to 13 at changes ;.or hour, which is recennended by Randley and 3artan (7) as applicable to single-family dwellings. The valua of :mo air changes per hour for de LS is also consistan: vi:h their :sesemandations for larger structures and apar:- man: bud'4dn gs. 7er ideal, ahal:ar -d* g, T = 0, and 7, = 0, de LS L provides abou: :wica the pro:ac:fon as de SS, which decreases v1:h increasing access delay :ina. Figurs' 29 gives :hyroid DRF plo:s for the same conditions as 71g. 28; sisca tha :hyroid dose is depe= des: only on tha van:112:ics rata,. scuavbac less pro:ac.1:n is afforded by the LS :han by :ha SS, because of da difference in ven:ila.ica ra:a. 71guras 30 and 31 illustra:a de difference is shal:ar protacti:n affordad for tha E and thyroid under ideal and less-chas-ideal con-ditions. In Fig. 30, 2RF values are given as a func.ica of T, for a icw air-cha=ga rata (0.125 hr-1) and 7 = 0. For T, = 0, the SS pro-2 vides a factor of abou: 2.3 for k'a-dose pro:se:1:n; whereas de LS providas a fac::: of abour 12.f-a :a14:1ve pro:ac.1ve advantage of 4.f-for the LS over the SS. In Fig. 31, for less-tha -ideal shel:ar-ing c=ndi:i:=s (7 =0.25 and L=1 hr~l), the SS pr=vides a fac:c: 2 of about 2.2 protacti:n for.he ~43 dose; whereas the

• .S provides a k'3 protactive factor of %.7-a rela:ive prc:ac:1ve advan: age of abou:

3-for the LS over the SS. he changa in the protec:1on for :he thyroid desa between ideal and lass-than-ideal snel:aring :::di:10:s 1.s abou: eigh:-fold; the shal:ar pro:ee:1 n fae:or =f the :hyroid desa is abcu: 40 for ideal c cdi:1 cs a=d abou: f for less-than-ideal condi:1ons. Figura 30 shews the esti=a:ad efface of da iodine ingress fracti:n ~ on da *43 DRF. D.e rise in W ORF is linear.*.:n de iodi=e i=g:sss fracti:n, vi:h de slopa pri=arily dependen: cc :he ven:112:icn air-change rate. "'ha 1: crease is :os: apparen for de LS, fo: repre-santative air change :a:as, and least apparent for :ie SS, for 1:v air-change ra:as. Again, this difference is due :s :he relative : n=ribu: Oc of de dose cenpene :s f::n radicac:ive sour:ss su: side and ins:.de :he am W 9 9 m .pp,s

• -.4 y

.s,ww., e c.

~.... -.. _... 75 o 1.0 l = l. s i l 0.8 ,3 L= 1.0 / 0.5 /

0. 5 -

~ SS g cm c 0.4

L = 2.0 LS ESIE3Se Ilme, Ig = 2 hr 0.2.- - -

2.x;:asure,,=e,.6, =.i hr / t. F t-i l c-0 O 0.2 0.4 0.5 0.3 1.0 1.2 ~T. (heurs) A

ig. 23--WB OR. versus 7,, case 3, (I =1,7 =0), SS (L=0.5,1.0,'.5), LS (L=2) 1 2

.c.Dem 6 N -""'T P '~---

76

1. 0 _.

l'. l. i i f i i l i i t 0.3 I w I I. t i i F r-- -L = 2.0 O.6 7 1.3 f7 = 1* 0.h /// w g 0.4 ; C' I 0.2 - r i l P l i .t-j i i I .4 1 4 .l 0 j e i l O 0.2 0.4 0.5 0.3 1.0 1.2 Ty(hours) Fig. 29--Tnyroid DFJ versus 7, case 3, (7 =1,7 =0), L = 0.5,1.0,1.5, 2.3 3 a 2 l gg,_ mge 6M O**

77 ~ 2.0 I, .l l i + 0 I i i l 1.0 [ SS g WB % Thyroid w a 4 0.1 / C.02 O 0.2 0.4 0.5 3.3 1.0 1.2

1. 4 T (heurs) 3.

rig. 20--WB and t.yroic CRF eersus T, casa 3, (T =1,T,=0,:.=0.125) 1 a

78 2.0 f f t l l 1.0 55 WB Thyroid LS u sE 0.1-0.02 O 0.2 0.4 0.5 0.3 1.0 1.2 1.4 T, (heurs) Fig. 31--WB and *.nyroid ORF versus T., case 3, (T 'l'I =0.25,:.=1.0) a 2 e,,- mes..m e . - -, -.w r--' Y e em h g

\\ 79 O e 0.3 1l 1.01 l l l i 1 0.4 i l

ss

-0.125 I i s s l 0.3 l l i i w K* l i l 1 l l I J i 0.2' - -.. 1.0 l I g i I i l I i I I 0.1 l i LS, r.. .e i s t i i l l i I i g; 0 0.2 0.4 0.5 0.3 1.0 1.2 Mcine ingress frac-icn Fig. 32-W3 CRF versus iccir.e ingress frac-icn, case 3, (T.=0,7 '0' a' 2

~. ~ ~. --- - ~ - - -. - ---- .80 l shelter. As indica:ed above, a value of 0.51 was used in :he calcula-

1ons for esti=a-dng the DRF.

If iodise ingress were 100 percent, de DRF may be from abouc 1.4- :o 14-percent higher for SS and f:ca abou: 16- :o 46-percent, higher for LS. Of course, for the thyroid dose, the l DRF could be nearly double (assuming ideal shelter-access ti=ing). Figures 33 through 35 are based on calcula: ions for the combi:ed pro:ac:1ve action of shal:ering and. evacuation. The resul:s shown are for the shel:ar ti=e, T, and.he evacua: ion ::ansport :i=e, 7,., which S

ogether would provide protec: ice equal to :ha: of shal:ering alene duri=g :he period of cicud exposure, !. The conditions of shehering e

are consisca=: vi:h ideal t' 'ag; i.e., individuals are assu=ed :s be is the sheher at :he :ime of cloud arrival (7 =0) and ex1: i==edia:ely 7 after cloud exposure (T.,=0). The c:mbined p;stec:ive ac:1:cs of sheher-i=g and evacua:1:n assu== da: i=dividuals exi: de shal:a: af:a a period, T, a:d evacuate during the period !_, whila exposed to :he 3 airbor:e radicactive cloud material duri=g 1:s :: ansi: away f :a de shal: : area. Accort.1= gly, if the s::ue:ure were ext:ad af:er a shal:a: period, 7, evacua:1on ou: of the vicini:7 of cloud exposu:e 3 should no: exceed :he :i=e period, !_, :o effec a dose procaction a: least equal s -hat pr:vided by stayi:g 1: :he shel:ar. ~herefera, ti=a mbi=ati:ss (T.T_) :ha: lie be:veen the curves and :he axes 5 s would gve rise :s grea:a: dose pr::ac: ice f m shehoring plus evacua-tica tha: fr:m sheltering only. For exa=pla, considering *=d-dose pro-ac:ica is d e SS shel:ar for low air-change ra:e c:nditi:ns and a cicud exposura period, T, = 3 hr, evacua:i== f := the sheher vi:1:i:7 should be ace==plished i= no : ore :han abou: 0.75 he if the sheher is abandened af:ar 1 he of cloud exposura; if exi: :akas placa af:a I hr of shehering, the evacuati:n :i=a da: should :o: be exceeced is shor: aced :o abou: 0. /. hr. U:dar :he higher represan:acive air cha=ge _t race of L = 1 hr ~, the.axi=u= allevabla evacua:icn :1:es increase somewha: :o abou: 1 and 0.5 hr for respec:1ve shehar-exi: :.=es f I and 2 hr, ass" # g a 3-hr :1 cud exposure period. ~he increase is all:vable :: ansi: ti=e, T. is prt=arily due to a larger dose incurred in de sheitar s::uctura bid de aigner a : change ra:a. g m e 56 e 6 & N-6 l r -- - - - - ~, - - - -,.,-n -.-wso-w,

81 10 L = 0.125 hr~1 --- L = 1.0 hr'1 % w. g ~ 5, e N O s N N N -~~~,~~ N \\ N \\ 3 1.0 s N \\ \\ N ~ s \\ e N g \\ E \\ \\ \\ .6 s \\ \\ \\ \\ ~~s's \\ \\ \\ s \\ \\ i s \\ \\ \\ \\ 3 5 a \\ 7 e 0.11 0.1 1.0 10 Sheltar time, 73 (heurs) Fig. 32--Shel:aring wi.1 evacua-icn, WB, 33--transi: time versus sneitar time (T =0.5) 3

81 1 i 10 ... -., e.. t.,T,. i i...iii .*i, m i I t I i it1 1>i:< L

• 1.0 hr_l.; l i I i -_l i I l _l

-r .1.,l .i.j i '.I, f g i ,.ji i 1.0

• w N

N 7 ---.~%_-- g s =r s N \\ ~ __'~ \\ ~ s N \\, = \\ \\ \\ \\ .= 8 a ~ N 0.1 t J N. ~ h:. N- '\\ \\. s.. T,

• 1 s

a 0.01 O.I 1.3 10 Shel:ar time, 73 (heurs) Fig. 24--5hei taring wi n evacua:icn, '43, Li--transi: :ima versus s. el:ar time (T "O

• 5 )

a h e -_._..g.-- - ~ - - - - .--w+-w -Y

.em m.* 83 y e 1 10 e e_ .e.... ,me,.,

p.,. e.i

.. u.- l t 4 L.a y,4g3 g .e.i. _l L_ _ ' ! ' i. ! L. L....---- L

• 1 3 hr~1.. '.

= -.. I I i.! i., i

• , ~.,

_ ~ ~ N. N ~~~~, g N N \\ \\ 1.0 - x g ._ m we N 63 \\ \\ \\ ~ \\ \\ E \\ \\ c a w d w N 3 7 N ,c N 6 k. 0.1 \\ . 3.- .T.- 1 t 3 ~ 3 O t t 0.01-O.1 1.0 10 Sheltar time, 73 (heurs) Fig. 35--Sheltaring wi a evacuaticn, :nyrcic--transi: time versus snel:ar time (7 =0.5) 1 ,.,...... ~ - --. -. ,-.~-i

+ 84 Figure 34 gives shel:e evacuatica break-even times for the LS shelter. ~ Tor lov air-change ra:e c=ndi: ices, =uch less ti=e is alleved for evacus:1cn frem. the iS shelter area -dan from the SS for a give=. .sbel:er-ez1: :1=e 3, because of th sWican y grea:er marrs of d Protection (lower DRF) offered by the LS. For de higher represac:a:1ve -L air change ra:e of L = h:, the allevable ::ans1: tima f::= :he LS shal:er again is less dan : hat for :he SS shel:er; but de :i=a diffe csce is so: as great as ccupared vi:h that for the icv air-cha=ge ra:e si: a:1:n. y Figure 35 gives the shal:er evacua:ica break-even :i=a po1=:s fce thyroid dose protec:icn. l'he lever =~'-.=2 allevable evac..a:ica ::a:si:

1:es 'c the lever air :ha=ge rate as ::= pared wi:h :he higher represen:a-

17e air dange ra:e are due to the larger =argi: cf pro:ection p::vided unen air cha=ge races are lov and acec dingly less :i=e is required for the ace"-"'s:i:n of :he break-even dose during evacuation f::= :he shal:er.

w =- e.e.- 3 e w.. g c_ esse -m

85 ? IV. CCNCLUSICNS AND RICCMfEGA"'!ONS Shel:ar protection provided by a large varie:7 of public strue:ures can provide a significant redue:1on is kB and hyroid dose f:cm ex-posure to radioactive gaseous fission produe:s tha: sight be released during a nuclear power plant acciden:. protec:ive shal:ering is at:rac:1ve if shel:er-access -' d g is ideal, but its effectiveness d*****=hes al=os: 11:aa:17 vich accass delay ci:e af:er cloud arrival. Shelteri:g protection agai=s inhala:ica exposures tha: resul: is thyroid dose depends on the number of air changes taki g place over the period of exposure to at barse radioactive cicud =aterial. Shel:ar-ing protection for '4B exposures depends on the attenuatics of ga=a radiation origi=ating from the airborne cicud source, :he cu=cer of air changes during cloud exposure, and (to a lesser exten:) :he atta=uation of ga=ma radia:icu origisati=g-fren :he ground fallou: about the shel:e structure. Accordingly, opcia za ve=:11acion ec==:ci l (low at:-change races during cloud passage) is scre effec:1ve for reduci=g thyroid dose han '43 dese. Albeit, van:114 tion con::ci is relatively ore effective for reducing kd dose in LS :han is 53. Large scrue:ures such as office buildings, sultis:ory apart =e : complexes, depart =en: stores, etc., generally would provide significa=:17 more shel:eri=g for ~43 exposures than s= aller s:ructures such as si:gle-family dvelli gs-a fac:or of about 4.5. ore during lov at:-change ra:e condi:1cus and 3 : ore for co 1:41 air change rates. sa: is, kd doses would be reouced by a fae:or of 2.5 cc 3 for SS shel:eri=g; vnereas for LS shelter _:g, kd doses vould be reduced by a fae:ce of abou: 12 during lov air-change rate condi: ions. For represents:ive air change race eccdi: ions, k1 dose would be reduced by accu: 1.3 for SS and fres 6 :o 9 for LS. ~43 dove can be fur:her recuceo in a shal:er s::ue:ure through use of expedient fil::s: ion; e.;;., by 3:uf fing cracks anc open-in:;s vi:h cloth or paper sate:1als,.-i:h would reduco :sdica::1.e ma:arial ingress (:iscussac acove, p.10 ff.) and/or :ne na: ural ven:11a: ton ra:e. 51=.1a:17, ano:her means of re:;i;;:c f procec:1on is :o cover :.e nose l l- --/

86 and mouch area wi:h such c:= mon 1:a=s as covels, handkarchiefs, or collac paper: e.g., a crumpled handkerchief (or one vi:h eight or more; folded layers), a :evel of three or more folded layers, or toilac paper of three or mora folded layers can. reduce inhalad radioaci:1ve macarial (pa::1culate iodine in this study) by a. fac:or of abour 10 (35]. na reduccica of WB dose in a SS, however, is not appreciable-about 2.5 percent for low ventilation ra:es and about 15 per:sa for represents:ive ventilation ratas. De redue:1cu in 'a~d dose in a LS vould be more appreciable-about 13 percen: for icw ven:114cion races and. about 70 percant for representative vectila:1on races. n a differesca in :hyroid dose p ctactics between SS and LS shal:ars is not as apparant as for W3 desa, because of the more nebulous correla-tion of buildi=g air change ra:a chas ga==a radiazion-a::enuacion pro-perties vi:h ete ger.e:a1 :7pe. of strue:.:re. D a degree of variab111:7 in the air change rata-an i= porta== paramaca: affae:1=g :he thyroid exposura-pres e=:s =aani=gful ?sti=a:as of the thyroid DU for SS as opposed to LS shel:ers. Accordingly, LS may not necessarily have any protective advas:sge for thyroid dose :educ:ics over SS or vice versa, due to any T-*er of factors-open portals, fil:ari=g ac:1on, air con-di:1o ing, s:::ctural i=:ag:1:7, ecc. Shel: art =g protec:ica for ei:her SS or LS, however, can rasul: 1: thyroid dose redue:1cn by a fac:or of f:cm abou: 20 co 70 for lov ai:-cha=ge races, and from a to 10 for repre-se= tar.ive air change ratas. nese ranges are prd_=arily due to che correspending range of cloud-exposure periods of fres 0.3 :o 3 hr, where the DU increasas, al:heugh see li=early with the air cha=ga ra:a (or nu=ber of at: cha=ges). A=other i=cor ant para =ecer affec:i=g the thy sid OU valua (also :he kd 3PJ :o a lasser ex:anc) is :he i= grass fractic=, wnich is ::aa:ad like an effective fil:ari=g ac: ice in :his s:udy. For that para =e:er, a vtlue of 0.51 was assu=ed for :ha radioicdi=es, based on review of 1' 4:ed exper1= ental ork discussed aoove (p. 10 f f. ). ne thyroid OU values gives vould : hen scala linearly vi:h vnacaver value is assu=ed. ne use of axpedian: fil::a: ion discussed above for '.3 dose can be eve. ore eff ec:ive in recucing :hy cid dose (i.e. recucing radio-iodi=e ingrass and/or ventila: ion by s:uffing openi.gs and ::acks c: ,n ,-g w----., n - m y 4

---

,-,.w,

,y, y,--cr

87 using such common 1:e=a es handkerchiefs and covels for respiratory pro-i taccion). Such expediant filtration could reduce thyroid dose by a factor of abouc 10 (35]. The protec:ica against *~a dose decreases 11searly with the amount of radioicdine penet: sting to the occupied spaces of a shel:ar structurs. ne decrease is more apparen: for LS than SS, because of the relative differences in the ga=ma ray attenuation from sources outside :he shel:er, and is also rela:ed :o che su=ber of air changes tha: take place duri=g the cloud-exposure period. To: :his analysis, an ingress frac:1on of 0.51 is assu=ed for 3 king DRF calcula:1:nal estimatas. Bis assuspcion i=plias tha: radio 11dise sources collect ac certain locatiens is the shal:ar s::uctures. D erefore, i= sofar as these locations could repre-se== "ho spots," local exposure of i=dividuals who =ay be adjaces: to chase collec:i n pois:s could resul: is dose increase. No a::e=pe has bee: sade here, however, to deal *.rith that problem other :han to =aka coca of it. Is view of curre=: unce::ais:y regarding pe=ecra:1:n of radioicdi=e into scrue:ures that could be used as shel:ers, the need for : ore experi=en:21 resul:s =us: be e=phasi:ed. S e degree of 73 dose procac:1:n afforded by shel:a se:ue:ures as a func:ica of cicud-exposure :1=a depends largely en the rela:1ve c=n:ributiens of :he exposure =oces. S e larger the relative exter=al dose cen:ributien fr:s pece::acien of ga==a radiation ist: :he shel:ar as ce= pared vi:h d-inha14:1:n dese, :he less the effec: of c1=ud-exposure c1=e en shel e effte:iveness. For example, for the SS vhere ga==a ray penetration is relatively =cre i=cor:an:, :he ORF would resai: relatively cens:an: for c1=ud-exposure periods up :s several hcurs. For 1 v ventila-cica ra:es, :he shel:ering protec ica =ay even increase somewha:--only abou: 1.3 per:es: c so-because of changes is :he radioisotope source six as a resul: of decay. For I.S shel:ars, where the 'a3 dose c:=penant fr:m gn==a ray pene-tra:icn is rela:ively less i==ortan: :has in SS shel:ars, :he degree of protec:icn still re=ains nearly :: stas: for cicud-exposure perices up to several hours for icv ven:11ati races; but for represenza:ive ven:ila:i n ratas, :he rela:ive pr:tec:ica f:r shel:ering d'-d-ishes I l l _.-_=s_- --~ ~ - . r --,--,---,_---,,,-------y m...mm-

+ 88 significan:1 --e.g., a fae:or of abou: 1.7 for a 3-hr cicud-exposura 7 period as c:aparad vi:h a. 0.5-hr period. he u:ili:7 of ventilazion rata con::31 is m4-4 4-bg the number of air ehm.,ges during sheharing, especially for LS,.1s. strongly supportad. by :he resul:s of this analysis. Maintain 1:3 low ventilation ra as is even mora i_por: ant from the stand-point of thyroid dose redue:1on for sicher LS or SS, as the loss in. protec: ion for the same cloud-exposura periods. sen:ioned above vould. amouse to a factor of abou: 2.5 for a representativa ven:11ation ra a of one air change per hour duri=; shaharing. Small-s:ruc:ura shahar protec:1:n for W dosas tends en hereasa somewha: with cloud arrival ci=a because of radioisecope decsy and corresponding changes is radienuclida propor:1ons. For LS shal:ars, procac:1:n ra=aiss-searly :enstan: vid cloud arrival ci=a, because of the relatively larger inhala:1:n dose c = pone:c; this holds ::ua even = ore so for thyroid desa protec: ion. Shel:ar procacti:n for "a3 desa d' ' '<hes for LS to a greacar ex anc than for 55 vi:h increasing ven:ilation races. To: a low ven:112:1c ra a (L=0.125 hr-1) as co= pared.with a.high ventila:ics ra:a (L=4 hr-l), SS shel:ar protec:ics d' '-4shes by a fac::: of %1.32, whereas LS shel:ar protec:1:n di=21shes by a factor of N2.7; thyroid desa protec:1:n decreases by a fac:or of s6. 9 The ac:anuatica of gn==a radia: ion fro = airborne radioac:ive =atarial ou:sida :he shahar strue:ure is = ora i=portas: to the W ORF :han thac l of ;;:cu=d fallout abou:. de shehar. Alsc, the effect of gn==a ray' ( a::anuation on the CRF f :s sources outsida :he shehar.is = ora signifi-far the SS than :he LS, whereas :ha c:nverse holds for :he ven:11a-can: tion raca. That is, a fac:or-of-two inersase is gn=ma attenuatiou asuh s is abou: as 30-per:anc incraasa is shehar pro actica for de ~ 1 SS, whereas a fac:ce-of-cwo reducti:n i: :he air change raca resuu s in only abou:.as 3-pe::en increasa is she'har protection for 'G dose. Ior Ehe LS, a fac:or-of-evo incraasa is cloud-sa==a attenua: ion :ssuhs I t is a SC-per:en: 1: crease in sheher pecta::ica, whereas a fac:or-of-evo i

scuc:icn is de air changs ra a gives rise :o a 2C-percan: increase I

in sha h s: protec:icn. l l e-M. 4 g 6 666 h - he me em me - m e -,,w- .,-~-p -__,,_w%.,, ,_q-s me -- y e-.

---

c,

t 39 The penaly in shal:er protection for :emaining in the shel:er af ter de cloud-exposure period depe=ds on the nu=ber of air c. a'..ges. 5 I taking place during cloud passage coupled wi:h the rela:1ve contributictr to da dose from isb212cica. klen air change ratas are lov, no sig=1-fican: loss of protec:1on for chs k3. dose in either-de SS' or LS' occurr,- regardless of how long individuals remain is the shel:ar af:ar cicud passage. '43-dosa shel:aris; pro: action is soc aff ae:ed very =uch v-;.en rema king in a SS af:a: cloud passage; for a LS, shel:er effec:iveness-may ha = educed f::s 10 :o 20 perces: by re=aining in the shel:er for a-period up to abou: an hour afte: 01 ud passagt. The shel:ering pr - tec: ion penalg is =uch ors pr:nounced for the thyroid dose, which can. amous: to a fac: r of abour a 1.2 :o 3 i= crease 1: the D u, as c:= pared.vi:h ideal shel:er-:d-d g c: di:10:s, should individuals ra=ain 1: :he shel:ar for a period up :o abou: one hour af:ar cicud passaga. The extas: :o which shel:arbg is at :ac:ive depends cc. :he :2:is of the projec:aa dese :o the p c: active ac:i: guide (?AG). Generally speaking, when da: ra:1c is c:=parabia :o de recip : cal of de OU, shel:ering is affactive as an e ergency procac:ive ac:icn. Also, for condi:10:s where :he projec:ed dose is so large as :: cause.acu:a injury, and :he predic:ad :i=e of cicud at:1 val praven:s eff ectiva evacua:icn, a redue: ice in dose by even a fac:o of 1 :o 3 =ay be qui:e i=sor.an:. The co=hinec p::cac:ive ac:icus of shel:aring f=11:ved by evacus-tien during cicud exposure (as oppose.i :o c=17 shel aring) can be. an-a::: active Opcien f::n :he 4:ancycis: of :::a1 dose reducti :. ""h e advas: age bec::es i:.creasingly _cre a:::ac:1ve as de dagrae of p::- tec ica offared by a shel:ar s::.:c:ura decreases and/or de cicud-exposure peri:d increases. La: is, f:: 43 " U censiders:1 :s, :he- - shal:er/evacua:ica op:1.n is generally more a::: active f:: 55 da LS and also for high air-c ange ra:e c di:i::s : nan 1:v enes. D e air-ra:a c ange :: sidera:i::s ara ::e i_per:as: f or de 15 dan the SS-as far as : e :pti:n advascage is :cacernec. and : s: i=:c::an: f:r dyroid dese pro:acti:. Icgist:: ally, de opti:r. an be at:rac:17e for cicud-i=e a -ival ::ndi:i::s :ha:. vouli ;;eclude eff ae::.ve evacua-ti: : uple:1 vi:h ine:essin:, peri:ds oi :1:ud ex:csu:e.

c. _

~ _u. 90 The6ex:e:Leo which the: resul:s for sheher effac:ive= ass developed is this. s:udy can be applied. :s the :alsase of particula:n-ai:bc== radicactive matarial f: z a suelaar incident can sac be quan:1.a:ively estimated. hara for two reasons:.. 1) the rela:iva contribuziot: : hat radioactiva particulatas saka :o tha :o:al, dose depends. on de ex an: of thei: release; 2).he ingrass of particula:a fission-p;cdue: =atarial. ints.shal:e: s:=ctures. may be differen: from da assu=ed here for gaseous radi:nuclides.. Overall, however, shehers would :and :o offer more.protec_i== 11 varying degrees than that indica:ad here fc :he gaseous fissi =.p cdue:. Therefera, applica:ics of :he DRF values :c pa:.1:ula:a.:alaasa matarial would be. conservative. Fu::her===:ic: , shculi be =ada for se=a specific considera:icas, t

Shelta: s:= tures vould be increasingly = ora effec:ive in reducing dosages f := <-hm!=:ica exposuras, for i= creasing p;cyc :10:s of par:1:-

ulata. relaasa, s1=oly because of affae:ive fika:1=g ac.1. To: 73 dosages,. shahar s =cturas would. tend also :c be sc=ewha : ore effac:ive; however,. :he ex:as: :s which da: =ay be de case is c:= plicated by varia-ticas is the dose c =pc=e== c..n nibutions. != general, however, whe de 'a'd dosa fo: senshel:a: condi:10:s (u=procac:ed) bec:=es p:cgressively mora attributable to particulates. -he ore aff ac:ive sheher_:g bec:=es. l

Also,

'.S shahams vould offer more pro:ac: ice das SS shehars f:: equi-vale== pa:.1:ula:a relaase si::a:icas. ( .3cch' experi en:a1 and analyti:21 verk is needed :o ::e accura:aly i l and specifically assess the p c:ec:ive advas: age of shel:aring. I:r the experi=== ai area, da ax:::: of radicac:1ve ingress in:o po:en:ial shal:e structures still re=a1=s unes::ais. Therefore, sc=a aff:r. us1=g represe:.a:1ee s::uctures (or odels) u=dar ::::::11ad sheher-s::ue:::e===di:1:ss and a varia:7 of c:= elated :::sorol:gi:21 c=ndi-ions should be under:2kan :s ob:ain reliabla =easure=en:s. t possible, the expe:1=e== should also address represen:a:ive particula:a 1:gress. Another experi=e : : hat c uld yield useful infer =a:10: fsr shehar-ing protac ion predi :1 = is da :casura==== of Ta ex:a=al ga==a dose f::= at::ome chud =a:arial !:r shel:a: s::ue:::ss== s: inside/:u:sida dese basis. Of c: ursa, such an undertaki=g =ay be difficul: in v:4v =f the is:astissal ::::::11ad release of :sdicac:ive airbo = =a:arial. e ah + eu.mu. .ummm.h e

91 L Such =aasura=a=:s, hovaver, could possibly be ob:2ined in conjunc:ica vid expe:1=a=tal progra=a carried'ou:'for krification of ce=pu:a codes used to predict off-sita dosas. (e.g. the ERDA Heal.h and Safaty Labora:ory p cg:s=s). In the analy.ical area, 1: vould be useful to. =aka.addi__':=al__es:1. _-- =ates of shal:a protec:1on for specific casas based on.= ore defi=1.1ve shal:a charac:aristics that =1ght es :espond to specific,loca:1c=s...-t u-The pri=cipal specific pars =a:ars vould be gn==a ray at:enuatica 41=1:n. sourca gec=atry-corrac:ica factors, at change rate, fallout deposi:1ce, and cloud a :ival ti=a. Also seeded is =cdel i=preve=ent regarding radiscuelida source c:=ponen:s. To that end, it would he useful :o assess the affac: cc :he shel:e: ::RF vhan para =:-daugh:ar decay is considered aloca vi:h specific a::a=ua:ica and f1=1:a soc ce-geese::f cc :ec:1 = ac: ices for each radic=uelide. F'-="_y, additional analytical at:an:1:n should be given :o i=clude. esti=a:as o:'"shal:ari=g pre-taction for radi: active airborna releases :ha: cen:21: par:icula:a =a:arial. Such a research eff= : vould focus on the ex:an: and na:ure of tan particula:es and :isi i=gress i=:s shal:a: s:: ctures. ORy as:1=atas vould also be. =ade using :he :7pe of odel, f.2: :he gaseous fissi:n-p;cdue: release addressed in this study. w ~ ~ ' .i s a. 4. J: .E. ..~. : s h

F t' 92 . Appendh A ~ YALICUT CA't!A SCURCZ t FINIH CT.CMETRY CURRiv.aON Conside: :he falleving skatch for :he dose calcula:ad at a vertical distance d from a plane source of iso ::pic gn=a-eni::ing na:erial of ' 1 source s::eng:h FL (gn=as/cm /sec): -S a 9 f d z? S The dose ra:a a: ? fr:n an annular scur:e, radially bounded fr:s a, :s R ' 18 2 star).-u-3(1,,A,) = is 2:e d: (1) a up .L wnere k is a dose conversion ::ns:ss:, 3(ar) is a ga=a-ray dose buildup fae:or, and u is :he ga==a-ray absor; ics ::effi:ian:. O.e :2:io of :he dose 3(0,R) :s O(0,=) is defined here as :he fini:e plana-scur:a geene::7 correc:1:n fac:ce given as m rs-h

d 93 c'(R) = D(R) O(0.R) D(1.=) D(=) D (0, =) = 1 D(0,=) (2) = 3 Assuming the 3e:ge: buildup factor for:2, and sisca :~ = p ',- d", N kS (1+ Car a "#) ',.u: D(R,=) = dr YR s-iA A = = kS -u dr - Ca e (1-0)a' dr (3) 2 YR.11 A .2H Subs:1:u:ing u = ur for -he first is:agral, and evalua: ins: I, kS -u -(1-0)ur ! n e Cu e D(R,=) =

u -

u (., -D J u _i,, .u NR~-d' u Y R'-d'. f 2 2 C

., 2 NR H e (1-D)u R -d (I.)

2 = (1.) w visera I,(x) is :he firs:-orda: expenes:1.21 is:agral fu==::.:n. ~.:en, si=ca D(0,=) = (R,=), lis R,3 y3 I, ( d ),- (.,,C e (' 0)"'d O(0,=) =,- ~- (5) ,s)

94 t Appendiz 3*' DOST. RCUC""CN FAC CR DOSE COM?cNDITS-CISEI mr

• "3 Falloue (*a-= Source The ou: side-fallou deposi:ics ra:a 14 assu=ed :o be 2

dv(~) " V. 6* ~ \\?(*) (1) d At Mul:1plyi=g (1) by the 12:eg:s:1=g fac::: e 1: d?f:) 1 ale -(:) = 7 v e d e. g c whi.i es=. be.r:10:an as the :stal differentisi, d la -- [e 7(:)] = 7 x (2) d. gs

• hes, is:ag:s:ing 1.e d (a ' F(:')] = 7,2 d:'

s 3., 0 0 we have .e'.' F(:) = 7 X 3 33 and :he: 1 .- r.,3_u.. y x.. ^.- w -,r -- -4 s. 3 = !ar:s usec in :his appendix are lis:ad en p. 100. e .w e m&mggu.m. h.*

95 [ The fallout dose during cicud passage where x, f 0, over :he is:arv41 (0.7 ), is e T T e -4: I F(:)out dc = 7 K.x e d: (4) 4 g*o 0 0 In:egra:ing by parts, T a -A: e -AT i -At dc = -(A -1) e e

e 1"*

I T -1) (3} ~ 1 e A O 0 ~ Af:a cicud passage, the residual g:cund falicut is ~*. I' (:) ou: = F(T )cu: e e The 'JB ga==a dose accu =ula:ed over :he period (!g-T ) af:a: cloud passage y f := res14ual falleu: is (T,*T ) -x K. T'(:)cu: d: = K F(T )ou: e 4: e 0 0 4(T-T){ = K ?(T )cu: 1-e (6) e .s The cu: side :sfaranca falleu: '43 ga==a dose (ung:c:ac:ad) due :o 3:cund-falicu: deposi: ion as given by Iqs. (5) and (6) above is + c, .m m

s-t t 96 i - AT t FD -V XX L - (AI +1) e e o go4 2 e g t -17 T e -A(7 +r ) e 1 v +- 1-a x rem (7) COSI CCMPONIN 3-5'dILTIID Airborne Source ~Inside The rate of change of :he at:bor:e concent::: ice in :he shal:e s: ucture during cicud passage is dC(:) -A: d: " CL, e - KC(:) (3) X K-Choosing e ' as the is:egrating 'ac:c a:d :evri:1=g as :he :o:21 differe::1al, h[e C(t)] = cx,L e (9) where K = Lv1-K, and K-A = LvK,. !=:egra:i=g cve :he is:erval (0,:) where C(0) = 0, g. (L -K,) :' cx,L ' (L-K,): e ' C(:) = cx L e d:' =, K, e -1 o sv 0 and :he conces::acie is cx,L C(:) =... (a - e '.') Ci/=3 (10) u s, The dose in :he shel:s s:::c:ure is given by is:agra:ing :he===- ces::a:1:n (10) =ver :.e 10:erral (T.,T,) at: nul:1 plying by :he appr:pria:a ~ ->e. ee.

97 dose conversion and fini:e-source correction fac: ors designated here by c: 'l 'D=c C(:) dc 'l ~ c:x L -AT -AT -C -C o 1 e 1 1 e = - e -e e -a res (11) (LvK,) A 4 Af:er cloud passage, che conces:ra:Lon is :he shel:e: s::ue:ure as a func:1on of :1 e is cx L -C -C C' (:) = K., e -e e C1/n (12) v o and the dose ac:usula:ed is :he shel:er s::ucture over :he period 7 2 af:er cicud passage is '2 D=c C'(:) d: 0 ccx'L -a7 -C -C, e -e 1-e rem (13) = (, %. 4.. Serf ace f our:e-I-side Is :te shel:e: s: rue:ure. :he ra:e of change of surf ace-fallou: depesi. ion (assu=ed :n : e floor space) is nr.3 V',Cx L, _', y = 7'C(:) - AF(:) ={ (a ' -e - A?(:) (14)

. - ~ -.. ~ - -,. - - .l t 98 Again,. choosing the i=cagra:ing fac:c a and ravri:ing as ths

s:a1 diffaran:141, V cx L.

1 [e *?(:)] = (LM,) (1 - e, *) (13) de whara K' = (LtK,). Then, iscagra:63 vners T(0) = 0, V'cx*L A*7(:) = (Lt,) (1 - e ) da.' e O V'ex L .. _1 ($.e-K,:) t o (trs,) K' giv1:3 the insif.a fallou: deposi:10: as ,I,. C X,- ?( )in (.,',,-K, ) ta \\' 1 (s.1-3 7 = e ' ') Ci/s' (16) L ~ The

• ~3 estarsal gn=:sa desa accu =ula:ad over (T,,7 ) is

. e ?'e 73 - G'I, F(:),s d: 1 = e 'l c'v'ex Lx e e t e -4:. (e c -K:) d: .(.4) =

e a:

(' vs. ) 4 e

• 1

'l 6:ag:scing I:;. (17) above (firs: intagral by parts) gives -e e ~

99 v'c'ex tz. -a! -1T 1 1 e t o = FD (AT +1) e - (17 +1) a = 3 (L+K,) 3 1 e A -1T -1; -C -C I -:--(a 1 1 a 1 1 e I -a e -e tem . (,3) IA K,K / Af:ar cicud passags, the ac:::mula:ed falleu: lavel a: ; is gives by = e Z. (16) avalua:ad a: Te (7(T ),n), which di=isishes by radioac:ive decay. 4 a. The *.T3 ex:e==al gz=r.4 dose accumula ad over intarval !! *i*'r *1 " passaga is 7,' A. FD., = G'X,7(T ),s e ' d: + a. 0 -1; 7'G'cx II., 7 e - i.*, -K:) 1-a ra= t s e -se (a -e = (. n.. A .s 4 ( *,9 ) t Aftar cloud passaga, the :=ntinui:3 fallou: ra:a i: ::a shal:a: s::ue:ura due :s residual airborna radici:d1:a is d'? / -) c,.' = 7'C' (:) - 17(:) (20) g 1 where C'(:) is given by Iq. (l'). Checsing a ' as :he in:agra:ing fac:s: and rewri:1:3 as :he :s:a1 differen:ial, , \\:.(:)] = 7'cy L -\\T -C d 2 o e e -4,: (., Le : a -e e (L-K,)

• agra:isg Whers ?(0) = 0,

~ - ~, -,w, - ~ ~ - - - - - - -. - - = ~ = -. - - -

r --:=---.. 4 100 g. V, tx,. -1 _g,;) g 3 e,.4 (t) = (LtK,1 e -e e de 0 7'cx L -AT -C s t o e e \\ (1 - e-E, t) e -e (LvK )K, giving th'a i= side-fallout deposi:1ca af:ar cicud passage as v'ex L AT -c t e e e -At -, (c),, = (LtK.,) K, -It) e -e (a -e ras (22) The 'aa ex:a:=a.1 ga==a dose _ dua :o i'(:) accumula:ad over is:arval T af a: a cicud passage is g

• 2 E3
• C'K.

E' (:),s de 0 V'G'cx LK, -AT -C l -K.:) de t e e a -se (lek.)K,- = e -e (e e 0 V'G*ex LK, -a; -c -13 i / -C e e e 2 e -e 1-e rem. = g .-e K... t (LTh.. ) .{..A \\ .s (23) ~~ Surface 5eur s--Ou: side 7t.e *"B ex e::al ga=ma dose accu =ula:ad over '"., is T T 1 e D' = K T(:)cu: dc = V K (o 3.

e

d: o 0 0 e g.m e e ,m_ mom .e ewm mm 6

~ 101 e Integrating by parts, V K -17 '. o s. l TD' = 1 ~ ( T *l) * (2') 2 l S1:silarly, the

• ~d exter:41 gan=a dose inside the sheltar s::ue:urs ace =nulated over is:arval (T,T,) f :a ou: side-falloue deposi:ics is y

. e FD'1 = A'K, F(:)out de .'s. A'Vte, X K -AT -AT " 1 e (17 -1) e - (A7 -1) e res (23) 33 7 e SEIL IR2IC A2C E7AC"ATICN-VIE!CLE,t*?.20?lII CCNCri RAT!CN The rata of conces::a:ics change is :he vehicle is dC) -\\ = cx L a I C(:) (26) d w. oV V whers K = L, + 1. y I: v Choosing e as :he 1::agra:i=g fac:c t=d rev ::isg, ~K: L: d v v f.- a C(:) = cx L e (27) w oV Is:egra:ing vnere C(0) = 0, K L: e '#: C(:) cx e -1 =

.i__,- e l 102 and :he concent:stion in C(c) = cx,(a-Ac -K : v 3 -e C1/:n (23) DE!!NI !.ON CF TUMS T(:) = fallout (per uni: araa) C(t) = ins:.da at: borne concen::ation (per unit volu=e) x, = ou: side at hor.e concen::a:1:n (per uni: volu=e) 7 = deposi:1on veloci:/ outside V' = deposition veloci:7 insida K A = rad 1: active decay cons: ann (per uni: :ine) Kg = fallou: dose c nversion constas: e = desa convercica cens:sn: T, = cicud aposure pe:iod T, = shel:e: entrance de'ay ;eri:d Tg = shel:ar period af ter cicud passage ! = evacuation ;eriod away f :m shel:er L = ventilatter. urnover rate (per uni: :1=e) K, = 7'/?. (per uni: :1ne) ~ 1 = nens fa*.1 dis:ance' for iodice insida K = L e 1

• K, c = in;;; ass f:se:i:n G' = ft:1:e-scu::e cc :acti:n f ae::: for fall:u:

L,, = ven:11a:1:n turncver ra:a f:: vehicla (per uni: :ine). e4 m g, e.i> Meimse gm a em aw*

...u-. 100 RIyIRINCIS L. Esca::: Scfa:j St.4dj, Appendi.: 7?: Cahula:icn of Rec:::r Accidan: C:nsequances, WASH-14C0 (Draf:), U.S. A::mi: Isargy Cec =14sien, Augua: 1374. 2. 3all, M. J., CRIGES--The CENS :sotope Centra:, n and :epla:-:cn Ccda, CNR.-4623, May 1973. 3. JacI4cnics, Da a Shee:: No.1-30, Mar:h 1955-February 1959. L. 31e ?c:tn:,.*, 2:di togic i :-~;ii ::i:na of Su:itcr Taci*i:ia2 in ~hs V.:,.cer.Viasiasipp-: River 3cain in :he face 2C00, VASE-12C9, U.S. A::=1e Isergy C =1ssi:n, January 1973. 5. Scdickgical Esc!:h E.~.dheck, ?3-1211734R, U.S. Depar =as: of Heal:h, Iduca:1ca a:d Velfare, Public Heal:h Se: ries, Sapts=her 1960 (Rav. Id.). 6. Sabersky, R. E., D. A. Si=ama, and 7. H. Shair Enriren. Sed. TechncT.., 7, 19 73, p. 347. 7.

Handley, "l'.

H., and C. J. 3a:::n, E:ma Ven:i:::i n Ec:ts: A Ii:J:::.4rs Surrey, Ch*RL-Df-4313, Septa =ber 1973. 8. ?:1 vata c==unica:ica vi:h Ce==14 I, atha =, ics Angeles Ci:7 3uild-i=g a d Safety Depar:=en:, Health 31risics. 9. Yocu=, J. I., W. :. Clink, and v. A. Cats, "*.:dcor/Cu:d:c: Air Quali:y Rela:10:s 1ps,".*. Air ?cl*,. Cen:r. Asscc., 21, May 19 71, pp. 251-259. 10. ASERAI 2.~.dbeck of Tur ent !4, A erica: Socia:7 of Hea:isg. d Refrigerati:n, and Air Candi:1cni=g T.sgi:aers, Nav Y :k, 1967. 11. Cablan::, C. V., and ?. R. Achechach, AS2242.Teu: c!,, 5, 1963, p. 69. 12. Megav, W. J.,.~n:!..*. Air Va:. Fo!!., S, 1962, pp. :.21-123. 13. Kaba:, M.J., "!: dine For=s and Removal Ifficiencias," panel Discussion (Radioicdice 3e.-avier Rela:ed :o ?:ver Reac:100), .~r:ns. Amer. Suci. Ecc., 22, '975, p. 36. 14 Priva:a ::czunics:ica vi:h M. J. '.f.aha:, Cn:ario Hyd:c, ?iciering, Cu:aric, Casada. L3. Haulay, C. A.,

., a: :L., ::n::: :ad in :i.m:~an:=L 2 di:-1:dina

.~2s:3 c: :he Mc:-1:r,:5 Re::::: :ss:ing 3:::i:n, 365 ?::gress Raper:, !!,C-12047, Februa:7 1966. ~~

t, 104 4 16. 31ggar, 'M. M.,1. J. Crew, and R. K. Fuller,.Ycn-Ingssud Ccse Associaud uich ?. *:i:uicu :ngress in:o a ?:::c:ype Shel:a: Y**,c, the Ven:ik:-L:n Sys:ar::, USNCL-n~413, Janua:71965. 17. Burson, Z. C., and A. I. ?:cfic, 53 rue:ure 5his! ding f.mm C*: d and Talku: Cc~r:c-P. y Ecurass f:: Assessing ha C:nsequences cf Recc::: Accidents (Draf:), I.G.& G., Las Vegas, Nevada, March 1975. 13. Chabo, G. I., and L 'J. Skrable, "A Si=ple For=ula f:: Istir.a:1:n of a Surfaca Oose and ?he::ns I:1::ed f::s a Tini:a Cicud," Se:L:h ?hysics, 27, Ju17 19 74, pp. 133-133. 19. Cesign and Revieu cf 5 :ac:ures f::.%::sc:icn f::m Ecihu: :c:: Rcdia:-;cn, ?M-100-1, Oepat:..es: of 0efanse, Office ef Civil Defense, February 1963.

20. Aux 1ar, J.

A., J. O. 3nch m, C. Eisenhauer, and E. I. Me iar, ?: peri =en::L Erciuc:-: n of '.hs li diarkn ?:: ec:kn Aff::ded by Eas-:dancia: 5true:ures Ag= ins: :h::ibuud 5 cur:ss, Cu-58.1, January 1969. 21. ?s:sen, I. G., D. ?arry, and H. Zoralia, Imperimental I !u::kn of na ?:Lku: 3 iia:kn ? :n :kn Aff:: dad by : Ecu:l: es:ar: ) Residancs, CH-40.5, Tehruary 1962. 22. Eurson, 2. G., E::erimen::L ?:dk:kn.Ve::ure en:s in ::nven:-:Cna: 1 1 52:ac ures, ?::: :, C H -59.73, July 1966. 23. St: :kler, T. 3., and. J. A. Auzier, I perimen :I 2 c!u :kn af 'J:s 2:dia:icn.bcuc:=:cn A.'.':: dad bu.~b.:hai Cck Rid:a 3:1 es Agcirs; :h: ibu:ad 3:u :ss, CH-59.12, April 1960. 24. Sc=ners,1. L., and I. G. 3ursen, I: erimen.:! I cine:icn of ,,,tCnn q'.ses,:: a;;'::*%r.: :::.Cu:.= :22u':.ar. *n ::? 3 Ic32::2n:3> s s CC-65.3, Oece=ber 1966.

25. DC?A A::::h Envi :r: en: M:n u::, Chap;e: 6, "*4.a: :he ?' a==e: Needs

s K:cv Abou: Fallcu:," C?G-I-IA6, Oefense Civil ?:sparacness Agency, Depart =ent 3., Defense.,iuse 3 0.

26. Su: son, ".. G., ::erimen::L EucLu::kn :l :ha ?::hu: 2:ii::-::n .'%cuc:-: n ?::v-lied by 3 :u::ures in :he ~:n::: ?:in: A e :f \\

hs.Vevci: :ss: Si:a, CD-69.5, Oc::be: 1970.

27. Surson, 2. G., i::e~ ixen Euciu::kn :l :he ?: hu:-2:ii :-::n ?::uc:-kn.=revidad by sakaud 3:: a::ures in :.a L:s Anga:as Arec, CH-61. /4, Febr..a: r 1963. 23. 3cralia, E., 2. G. 3urson, a c J. Jac:vt:::, Isch::Qn af :he ?::Mu: ?-:ue:kn Aff:: dad by 3:::k:::ven.7c:kna:

• h::::::j

.Ysdicci Rese rch Cen ::, CZZ-40.1, cc::ber 1961. m.- e

r L 105 29. 5: eve =s, P. N., and D. K. T:uhey, k'eqcns Rciic:'cn Shia? ding Ecndbeck, Chap: : 3. "Mathods for Calcula:Ing Neu:: n and Gamma-Ray A::enuation," DNA-lS92-3, Rev. 1, March 1972. i 30. Ramsey, W., and P. R. Reed, L:nd use end Jue! ace ?::.se ?!,=::4, Cess Studies of Sicing ?reblarris, WASH-1319 (no date).

31. Manuct of.%:acr~:::a Ac:icn Guidas and ?rc:te:ive Ac:icns fcr Nuclace Ir.cidanza, U.S. Inv1:en=en:21 ?:o:ection Agency, Office of Radia:1:n ?:ograms, Environ =en:a1 Analysis Division, Sep a==e 1975.

32. D1:katson, M. H., and R. G. Orphan, A:: es-herie Es!JcJa Ad:liJc:*/ Cc c.bi;i:y (A?AC): :avelcy. en: cr:d ??cns fcr I. pla. sn:c:icn, UCRI-51339, June 1975. 33. Bursen, I. G., EscI:h ?*:ysics, 2S, January 1974, pp. 41-44 34 Pe:ersen, G. A., and R. H. Sabersky,.*. cf ths Air Ec!;. Cen:r. Assce., 25, Oc::bar 1975, pp.1023-1032.

35. Guy::n, E. G., e: cl., A.3. A. Arch. :r.du.s. Reci:h, 22, Aug~:s:

1959, pp. 91-95. .u====, -.=.m.m. aim - - - ~ - i

p t 8 I ..T. g Il ik]ma m. e 6 'l 9 9 e-eum e t 1 R. 3 -:) -2 e r-u =5

• 1 O

Il

• E E

-35 2 c ~3 2 m 1,. 3? w

- a =-

wi -= =a Dwn3 QS ' ' ~ ' - ~ ~ ~ ~ ~ - -

• N e ag m,

2}}