ML20212P770
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| Issue date: | 01/10/1985 |
| From: | Martin J NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES) |
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.b 11/84 PREPRINT: FOR PROCEEDINGS OF TIIE $I'GHTEENTH MID-YEAR TOPICAL SYMPOSIUM (ENVIRONMENTAL RADIATION '85) 0F THE HEALTH PHYSICS SOCIETY, JANUARY 6-10, 1985, 4
COLCRADO SPRINGS, C0.
OBJECTIVES OF EMERGENCY RESPONSE AND THE POTENTIAL BENEFITS OF EVACUATION AND SHELTER James A. Martin. Jr.
Division of Risk Analysis and Operations Office of Nuclear Regulatory Assearch U.S. Nuclear Regulatory Commission Washington. 0.C.
20555 t
A85 TRACT 8asic radf ation protection objectives for the controlled enviroment are transferrable verbatim for use in the uncontrolled or emergency situation. These objectives are:
~ avoid near-term injury or fatality and reduce individual risks and total health eURts to levels as low as reasonably achievable (ALARA). The i
potential benefits of sheltering and evacuation in meeting these objectives during a response to a severe LWR accident was investigated. It could be very difficult to reduce total health effects because collective dose (man-remi increases mono-conically for sco es, perhaps hundreds of miles free a release point. In this regard, shelter and ad hoc respiratory protection appear to be the only rational and feasible near-term protective actions that would be available to most people.
Howver, the first two objectives can be met by early. precautionary evacuation.
within two to three siles irmediately upon the declaration of a General Emergency (e.g.. a core melt accident), and sheltering elsewhere. In the event of an actual major release later relocation from highly contaminateo areas would be an i
integral part of the mergency response. Analyses performed to investigate the various emergency response options and potential benefits are described. The perspectives obtained should be reflected in emergency plans.
INTRDOOCTION Radiological mergency plans for fised nuclear released to the atmosphere) (US81; US82a). Al though facilities should be constructed to achieve spe-these ' source terus' are being intensively inves-cific radf ation protection objectives in the event tigated (8484) and may be revised in the future, of a future radiological release. Basic radiation the NRC set was used as the best current estimates I
protection objectives for controlled environments, of severe accident source terms. The important such as a wrk place, can be succinctly stated as characteristics of this set are listed in Table 1.
follows:
These would all be core melt accidents. The o
AVOIO serious non-stochastic radiation effects estimated probabilities of these accidents occurring (i.e.. near term or early, injuries and are very low, but the estimated release fractions fatalities), and (of the core inventory) to the atmosphere would be large, especially for $$T1. In general terms, o
REDUCE individual stochastic risks and total SSTI would correspond to a coincident early, latent health effects to levels as low as massive failure of contafrunent. with little or no reasonably achievable.
scrubbing of the release by engineered safety features in a plant. SST2 would correspond to a These basic objectives are transferrable directly coincident major contairment failure with degraded to the uncontrolled or accident envirorment, so performance of engineered safety features. SST3 long as it is recognized that there can be no guarantees proffered that all objectives can be could involve a late basemat melt-through accident.
set in all conceivable circumstances in an uncon-witn efficient scrubbing of particulates and a smaller release of noble gases, as well.
trolled envirorment (US78; US80; In84). For this paper the potential berefits and practicality of BACKGROUNO cnahtaations of evacutica and shelter to achtsvs these objectives in resoonse to severe Ifght water Clearly, even without an emergency plan some nuclear power plant (LWR) accidents was investigated, off-site mergency response by the pubite would be expected in the event of these accidents. Examined The LWR accidents considered was the set here es the question: leat would be a practical
$$T1. SST2 and SST3. suggested by the U.S. Nuclear Regulatory Commission (NRC) as representative emergency protective action schee involving groupings of severe accident source terms (frac.
evacuation ar.d shelter, dich would satisfy the basic radiation protection objectf ves? It was tions of the core inventory of radf onuclides recognized that individual entrapment situations 8703160253 870312 FOIA f*
/
CURRAN 86-849 PDR A
can be readily visualized; thus, the perspective o
In the further event of an actual major was to investigate evacuation and sheltering atmospheric release from containment.
benefits that could accure for most of the people people in shelters would relocate from most of the time given the postulatec eccidents.
highly contaminated areas lef t in the Certain leading clues were available from we e of the M ease, previous studies. Three are especially noteworthy.
In NUREG-0396 (U578). risk ys distance was displayed g
in a simple manner in a figure reproduced here as would not involve early conteiraient failure (U575, Figure 1.
This figure merely indicates that dose B4 WN H h WW m%
(and risk) n distance decreases monitonically that only about one out of ten core melt accidents from a source point for an atmospheric r ase.
might lead to an 55T1 type of release, on the a r% Fu h mm W Mu "u4 Theoretically, the decrease varies as r-approximately, where r is the downwind distance.
precautionary evacuation...in the event of a core Because of obstructions, wind meander & wind W t. ws used above.
shifth during a release period, dose might more realistically vary as r-(inverse squared). The A version of the CRAC2 code which provides r.s (inverse distance) curve in Figure 1 was g
f included as an aid to the reader. Without further the calculations (U583a; U583b). People in elaboration or caveats. the information in Figure 1 gg can be taken to indicate that protective actions for each of the three major pathways-external within a few miles of a release point would be gassias from the plume. Inhalation, and ground most beneficial because the risk is clearly greatest contamination. These protection factors are within this distance.
typical for residences with basements (U575).
Two other clues were provided in NUREG/CR-2239 (U582b). especially in two figures reproduced hem Evacuation mes modeled in the first, or as Figures 2 and 3.
Figure 2 displays the probabii-near, zone by assuming a one hour delay af ter an ity of exceeding various msebers of early fatalities initial warning (e.g. declaration of a General given an 55T1 accidental release and variou*
Emersency by tne piant). and a 10 mph evacuation
~
emergency response asseptions. The bottom curve speed radially away from the plant. thder this in the figure clearly illustrates the potential assumption, people begin to leave one-half hour benefits of a minimal delay before evacuation, af ter the 55T1 release begins. The assumption For the stsenary evacuation curve; delays of 1. 3 that people leave one half hour af ter a major and 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> were assumed to occur 0.3. 0.4 and 0.3 release begins is a generally pessimistic one, of the time respectively. thfortunately. for the This certainly should not be the planned sequence, This has been noted previously (Ma77. Ma80. Me82 bottom curve in this figure an evacuation within Bu84).
twenty-five miles was assumed, at a speed of 10 miles per hour. This implies that a large area The second, or mid, zone extended frem the could be cleared in 2.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> - hardly a practical inner rene to 10 miles. People in this area wre assumption for most people most of the time, assumed to relocate after four hours exposure to ground contamination lef t in the wake of the puff.
Figure 3 contains two important clues. Shown The third, or far, zone extended from 10 miles.
here is the conditional probability of incurrin9 Here, people wre assumed to relocate af ter eight an early fatality beyond various distances assein9 hours exposure to ground contamination. These the 55T1 accidental release and various mergency relocation times were estimates of the time it responses. Again, the importance of a minimal delay before evacuation is clear from the bottom would take to locate hot spots, provide notifi-cations, and for people to move a short distance curve which indicates that with a short delay time (Ma77. U584) away from the hot spots.
the early fatality distance should not-exceed two miles. Again. the impractical twenty-five mile The New York City meteorological set in the evacuation distance is noted. Further, as indicated CRAC2 data files was used for the calculations.
in this figure, all shelterees were,tssmed to This set contains rainfall about eight percent of stay on contaninated ground for a full day before the time. Rain can cause heavier than normal relocation to uncontaminated areas. This 15 ground contamination. Also, the population distri-hardly a realistic asseption considering that butions in the CPAC2 data sets were used.
dose rates ir, many areas could exceed 10 rem per hour in the wake of the puff (U584). Relocation RESULTS from shelter would be expected to occur soon af ter radiological monitoring temas identified such
- hot Individual Risks spots".
Principal results of the calculations are CALCUtATIONS displayed in Figure 4 and Table 2.
As shown in Figure 4. for an 800 megawatt - electrical LWR at Following these clues, consequence estimates a coastal site in the U.S. rero early fatalities were performed using the following protective was caleviated for the most severe 55T1 accident action esse =oties -
postulatac, fw en early evacuacion oistence of three miles. The uppermost curve in this figure o
Early, precautionary evacuation within shows that the predominantly sheltering protective
- 1. 2 or 3 miles and insnediate shelter action strategy clearly suffers by comparison to elsewhere(General Snergency).
the early, short range evacuetion strate These in the event of a core melt accident results bear out the intuitive, qualitat e perspec-tive illustrated in Figure 1.
7 Y"
e M=~~
9 QNU en Y'
4 Identical calculations were performed for These perspectives are illustrated in Table 3 four other LWR sites in the U.S.
Principal results and Figure 5.
Table 3 is a samary of pertinent for these five sites are shown in Table 2.
Although information in NUREG-0340 (U577). dich illus-the CRAC2 population distributions of these sites trates the pathway and toporal contributions to were used for the calculations, the results we 1 total calculated latent cancer fatalities for the normalized to 500 persons per squart sile within PWR-1 and PWR-2 accident categories of the Reactor 10 miles. The power levels of these LWRs ranges Safety Study (US75). These accidents would be of over a factor of two. The results for the lowest the ilk of SST1. and would include substantial power level are indicative of dat results for the releases of long half-lived cesium radionucifdes, highest power level would be with a factor of two It is readily apparent from this table that long reduction in the 55T1 source ters.
term exposure pathways would dominate the total neber of latent cancers. (hly extensive and Several interesting aspects of the results expensive decontaination and condemnation are shown in, or may be inferred from, the infoma-processes over the long term would be efficacious tion in Table 2.
There were no residents within in reducing total latent cancers.
three miles of site neber one. and zero early f atalities was calculated. This illustrates the Figure 5 illustrates how collective dose and potential benefit of a very early evacuation of total latent cancer estimates increase with distance.
nearby areas i.e. before a release given a core This figure ws taken from MUREG/CR-2239 (US82b).
mel t.
For the highest pour levels, a few early Calculated total latent cancers accrue to large 4
fatalities were calculated for SST1 for site distances, regardless of the composition and neber two even with a three mile early evacuation magnitude of the release. Indeed, for the average assumption. These people wre caught by the front site fully half the latent cancers could accrue of the plume, in most cases. This was a high outside of fif ty miles from a release point.
pcpulation density site. In a.1 cases, several This phenomenon has been noted previously for tens of persons suffered early injuries (e.9:
routine atmospheric missions of purely noble gases (Ma/4). A Corollary is ihel Mir fiaId prodromal vomiting). Inese calcutates injuries occurred at various azimuths and to distances to emergency protective measures would provide little 12.5 alles, but mostly well within 10 miles. The benefit as regards the objective of reducing collective total neber of early injuries calculated is an dose and total latent health effects. However.
' artifact of the CRAC code, dich adds up calcu-for a purely noble gas release the cloud (external) lated injuries dertver they are located. At any genna dose pathway would dominate. In this case particular azimuth, no more than a few early immediate sheltering to large distances would be injuries was calculated, dich would be the case an effective protective action to achieve the for s single ineff. Further, these injuries occurred objective of reducing total latent cancers ALARA, at low conditional probabilities.
especially where sheltering would not be inconvenient This would be little different from an anyway.
In all cases, peak early fatalities and air pollution alert.
injuries were associated with rainf all, a sudden calm af ter transport, or stable meteorological The inter 14y between estimates of stochastic-conditions (low wind speed, narrow plumes, nightime latent cancer fatalities and costs of condemnation conditt or s). Emergency planners should be espe-of contaminated property is illustrated in Figure 6 cially aware of the import of these particularly for the $$T1 accident at the Indian Point site.
adverse, low probability weather conditions, dich The data points for this figure mere obtained lead to heavy ground contamination by particulates.
from IRJREG/CR-2239 (US82b). These are for various Separate calculations, not shown, indicate that for dose projection criteria for land interdiction the $5T1 release, calculated early injuries could be (condemnation). Normally in CRAC2. people are i
eliminated by slightly smaller particulate source allowed to remain in contaminated areas where the terus (lower ground contanination), better shielding, projected whole body dose is less than 0.25 Sv (25 f aster relocation or combinations thereof, rem) in 30 years. As illustrated in Figure 6. for
$5T1 a very large increment in costs would be No early fatalities or injuries were calculated incurred in reducing total latent cancer fatalities for the $$T2 and 55T3 accident scenarios, for the by interdicting property at a lower dose projection.
l noted mergency response assumptions, at all power levels, it should be clear from Figure 1 that One additional perspective is important in early, precautionary evacuation of nearby areas in this regard. For a core melt accident with fatture the event of a core melt accident would significantly of containment, the constituents of a release may reduce individual latent cancer risks in the event not be known for some time (Ma80; Ma82). Thus, of a core melt accident.
the shelter to large distance (where csnvenient) option should be predetermined, as well as the Collective Dose evacuation to short distance option, as an innediate response to the declaration of a General Emergency In contrast with individual risks of non-(core melt). Indeed, it was in this light that stochastic effects, dich would be relatively the protective action assumptions listed under near-fielo or close range effects, estimeiad ivisi Ciu.CULATION3, obv,.. w re r. eda.
latent cancers would increase monitonically with distance. Further, for releases which include a (he caveat is important here. These collective substantial abundance of long half-lived particu-dose perspectives derive from the assumption of a i
i lates, the collective risk would be associated proportional relationship between risk and dose.
with long term (years) exposure to ground contamina-tien. Thus fu otective actions during the energency phase would provide little benefit in reducing total latent health effects.
l I
w
-s
+--
--w----
=-y-
,,-a--y,v.
--e---r------e----
D!SCUS$104 The calculations discussed above show that in the event of a core melt accident early evacuation of relatively small areas near a Unt and sheltering elsewhere would provide sipificant reductions in individual risks of stochastic and non-stochastic health effects. The simple emergency response scheme suggested can be predetermined for specific in-plant energency action levels appropriate for the General Emergency class. Because the actions are so staple and easily understood, there is an excellent chance the plan would work. If need be.
The early, insnediate evacuation area suggested by these calculations is the size of many low population zones around LWRs in the thited States, and the early evacuation radius (2-3 miles) is less than the distance to the nearest population center of 25.000 persons, or more, at most LWR sites in the U.S.(US79). Thus. there should be few impedi-ments to evacuation in these areas most of the time.
A further conclusion is that reduction in collective dose and latent cancers aculd l
be very difficult to achieve in the early (emergency) response phase. Sheltering during the passage of a predominantly noble gas re-lease sculd be efficacious, but only if sheltering to long distances were undertaken.
A few caveats to these conclusions are noteworthy: There are large uncertainties in the absolute values of the results of the calculations.
Nevertheless, the relative potential benefits of v a ri ous eva cua ti on/ s hel te ri ng/ rel oca ti on prot ecti ve action strategies should be clear, especially where large differences in results are obtained.
At a few LWR sites in the U.S.. and at many foreign sites, heavily populated areas amist in the near vicinity. Witch could aske early. inunediate i
evacuation difficult. impractical, or impossible.
For these sites, better shielding protection factors may pertain and smaller early evacuation distances i
may be justified. (h the other hand, some low l,
population zones persist for many miles, and early, immcdiate evacuation of such areas may te a reason.
l able objective for a core melt accident.
It is acknowledged that entrapment situations can exist for some people or many people at some time. Early, imediate evacuation may be physically impossible or extremely hazardous during a snow or
' ice storm, for example. Special arrangements should be made in emergency plans for identified persons in early evacuation zones who suffer from significant impediments to mobility. In the event of a core melt during a highly immobile situation, e.g.. the ice storm, remaining in shelter and l
relocation from hot spots (if a release occurs) as quickly as possible wr,uld be the only reasonable and practical alternatives. These are highly unlikely ennhinations or unlikely situattans and l
the suggested protective action Scheme should l
satisfy the basic radiation protection oldectives for most people, most of the time.
Finally, as compared to the suggested predetermined protective action plans, protective action decisions can be made on an ad hoc basis at any time. The distinction between preceterminea actions and ad hoc actions is very important for l
emergency plannen.
w e
n_,.,.._.
REFERLNCE$
U578. U.S. % clear Replatory Comission.1978.
8a84 Battelle Columbus Laboratories.1984. " Radio-
- Planning Basis for the Development of State and nuclide Release LDider LWR Accident Conditions.*
Local Goverreent Radiological Gnergency Response BMI 2104 Vols 1-V1. July 1984 (Colustus. CH Plans in Support of Light Water helaar Power 43201).
Plants *, NUREG-0396. December 1978 (Washington.
D.C. 20555).
Bu84 Burke R.P., Helsing. C.D., Aldrich. D.C..
1984. 'In plant considerations for of f site U579. U.S. % clear Regulatory Connission.1979 emergency response to enactor accidents.* Nealta
" Demographic Statistics Pertaining to % clear Physics Jr.. 46, 763-773.
Power Reactor Sites *, NUREG-0348. October,1979.
(Washington D.C. 20555).
In84 Intertiational Commission on Radiological Protection.
- Protection of the Public in the Event U580. U.S. % clear Regulatory Cosmission 1960 of %jor Radiation Accidents: Principals for "Criter14 for Preparation and Evaluation of Planning.' Report for Cosmittee 4. Adopted by the Radiological Emergency Response Plans and main Cosmission May 1984. ICRP/84/C4-5/2.
Preparedness in Support of Nuclear Powr Plants'.
MUREG-0654. Rev 1. November 1980 (Washington, D.C.
Ma74 Martin, Jr., J.A.. " Calculations of Doses.
Population Doses and Potential Health Effects Due 20555).
to Atmospheric Releases of Radionuclides from U581. U.S. % clear Regulatory Commission 1981, U.S. % clear Powr Reactors During 1971*,
- 7echnical Basis for Est1 eating Fission Product endistian tota and Renorts. -34 309-319. June 1974.
3.h..f Gr 3.rir.; Ute a= 933.,3*, miem 077% June 1981 (Washington D.C. 20555).
Na77 Martin. Jr., J. A.
1977.
- Doses while traveling under mell established plumes.* Health U.S. % clear Regulatory Commission.1982.
Physics Jr., 32, 305-307.
US82a. Development of Severe Reactor Accident Source
"~~
- The Terms: 1957-1981*. NUREG-0773. November 1982 Na80 Martin. Jr.
J.A.
1980. 'Peupectives on the (Washington. D.C. 20555).
role of radiological monitoring in an emergency.=
Trans. Am. Nucl. Soc., 34. 727-729.
U582b. U.S. % clear Regulatory Cosmission 1982.
' Technical Guidance for Siting Criteria Develop-Ma82 Martin. Jr., J. A.
1982.
- LWR accident ment". NURES/CR-2239. December 1982, prepared by spectre-release characteristics aid consequences.=
Sandia National Laboratories (Washington, D.C.
in Proceedings of the workshop on Meteorological 20555).
aspects of mergency response plans for nxiear Power plants. NURES/CP-0032. %pst 1982. U.S.
U583a. U.S. helear Regulatory Commission 1983 Nuclear Regulatory Commission. Washington DC "Calevittions of Reactor Accident Consequences 20555.
Version 2. CRAC2: Computer Code-User's Guide".
prepared by
% REG /CR-2326. February 1983.(Washington, D.C.
l U575 U.S.% clear Regulatory Commission.1975.
Sandia National Laboratories October 1975 (y Study *, IRIREG-75/014. Appendia VI.
- Reactor Safet 20555).
l Washington. DC 20555).
l
)
U$83b. U.S. % clear Regulatory Commission.1983, U577. U.S. % clear Replatory Commission.1977
'CRAC Calculations for Accident Sections of
- 0verview of the Reactor Safety Study Consequence Envirormental Statements". NURIG/CR-2901. March t
I Neel*. NUREG-0340. October 1977 (Washington.
1983, prepared by Sandia National Laboratories
(
D.C. 20555).
(Washington, D.C. 20555).
j l
U584. U.S. % clear Regulatory Commission.1984 l
' Dose Calculations for severs LWR Accident
$cenarios,* NUREG-1062. May 1984 (Washington.
D.C.20555).
1 i
1 l
l l
~'
' ' " ' ~ ' '
~~
Table 1: Characteristics of Postulated 5evere Accident Scenarios Accident Type Release Characteristics 55T 1 55T Z 551 3 Warning Time Before 0.5 1.0 0.5 Release (hr)
Release Duration (hr) 2 2
4 b
Radiopclice Invengory Fraction teleased to Grovo (E8a) the Atmosphere Xe-Kr 13.
1.0 0.9 0.0064 1
27.
0.45 0.003 21'-4?
Cs-Rb 0.6 0.67 0.009 li, -5 'l Te 56 8.
0.64 0.03 2L-5' i
te 5r 14 0.07 0.001 1ll-4' i
Ru 21.
0.05 0.002 21 -
l La 110.
0.009 0.0003 1ll-I a.
As defined in the Reactor Safety Study (U575),
b.
For a 1000 MW(e) Lkt one-half hour after shutdown at Table 2: Results assuming 55T1 and five end of care life f 3 wears) fuS75).
c.
1 E84 = 1 Exa84 = 10 disintegrations /sec. Noble populati = eintrik ti u s.
gas plus I actigity equais 1.06 billion curies, d.
1( 5) = 1 a 10" Early Mean Mean Power Evacuation Number of Neber of Site Level Radius Early Early a
Number (MW-e)
(miles)
Fata11 ties' Injuries b
1 1100 1.2. & 3 O
60 2
1100 1
50 200 2
20 100 3
4 50 3
800 1
40 200 2
4 90 3
0 20 1
4 650 1
20 130 2
0 70 3
0 60 Table 3: Temporal and pathway contributions to latent canceg fatalities for severe 5
550 1
0 60 source terms b
Esposure Pathway Percent Contribution a.
Normalized to 500 persons /sq mile uite n 10 miles, and Time Frame m -t m -Z b.
No residents with three siles - equivalent to evacuation before a release.
Inhalation from Cloud 24 3
External Ground
(( 7 days) 13 16 Enternal Ground
( > 7 days) 43 68 l
Inhalation of Resuspended Contamination 14 2
Ingestion of Centaminated Fa^d' e
10 g
a.
From NUREG-0340 (U577).
l b.
PWR-1 and PWR-2 are severe occident release categories from the Reactor safety Study (U575).
Tne releases are of tne creer of 55T 1.
M h
.ee e mW w*M
1.0 0.8 Relatnre 0.6 Does Rate 04 1/r 02 g f,2 0
i 0
0.5 1
2 3
4 5
Dessance iiviiiesi Figure 1.
Relationship of dose rate anJ distance for a lo= level atz spheric release.
10k II.
_ _ _ _ _ -;2;
$5T1 NO EMERGENCY RESPONSE 1120 W (E)
I.P. SITE
[
i as
- r;-
h 10'I.
] Q".
at t:
A c
IHR DELAY 3
~
10 MPH Y
J E
SHELTERING g
8 l
=-I 10%
l I6 ".
v w
SHRDELAY l
10 MPH O.100 emergency response o - Susinary Evacuation.
SST) within 10 at 1123 * (E) e I hr delay 10 mph.
25 MI. Evac. Radius within 25 mi 24 HR. Relocation Time i
II 100
' 10I s
10' g '1 10' 10' l' '
10*
O l
K.EARLY FAT ALITY D15f ANCE (MI)
I, EARLY F4TALITIES l
Figure 2.
Impact of a range of energency response assumptions Figure 3.
Sensitivity of early fatality distances to on calculated early fatality probattltties, amergency response assumptions.
l l
It' z 8
SST 1
{
000 M W-e 10*'"E
.a d ias 3
.40
~
E 5 W *1 o
3 2
1.Early Evacuation M*,1 3
Redlue (Mileel E
10 8 i i sising i i i ns>>>g i i m issies e i v i s i ves i i a s s isi s
t a
8 8
8 ga gg It 10 10 10 X, ACUTE FATAUTIES Figure 4.
Conditional probabilities of various numbers of acute fatalities, assuming 55T1 accident, early evacuation of small areas, and a slow relocation f rom highly contaminated areas.
1.0 a
0.0 3373 l
_ g e-4 SST2 Esk 00 n<
0.4 3
SST1 h3 9,
0.2 Uniform Population Distribution j,,
sty: (u) * !atervention I
f O'
8 ' ' 5 '
O 40 00 la 180 M
l3-DISTANCE (MILES) 5 (0.5)
Figure 5.
Increase in calculated latent cancer fatalities alth distance for three source terms.
(0.25)
U'3 3 (0.05) 4=====...
e i
e e
a a
e a
vauseertamo._
---tenuomm Ftpe s 4.
Calculates mean 1staat cancee fataltties aas cost r
treasoffs fee several tenerelation asse levels (ssT1 accionat at lastaa e tat site).
s I
- - - ~ ~ -
AVAemi o
Radiation Monitoring for Emergency Preparedness at Nuclear Plants 727 operational emergency response system for the then AEC personnel concerned with implications of the release of radio-facilities. From 1976 through 1978, the major research and activity to the atmosphere. The local capabilities plus infor-development effort for the ARAC system was completed and mation received from the ARAC center can be used to the system became operational in late 1978. During these monitor the environmental impact of the incident, provide three years, the initial role of the ARAC service was ex-data for model calculations, deploy environmental monitor-panded from servicing DOE fixed nuclear facihties to include ing teams, provide a consistency between measurements DOE responsibihties in any type of accident that can po-themselves and between measurements and modehng results, tentially release radioactivity into the atmosphere.
and help provide information necessary for decisions related to protective actions that might be necessary.
At present, ARAC services four DOE facilities (Lawrence Livermore I.aboratory, Rocky Flats Plant, Savannah River Thus far, our experience has shown that the location of Laboratory, and Mound Facility), provides support to DOE these site facilities provides a focal point for the emergency emergency response activities related to nuclear weapons response activities associated with a particular site. Much of accidents and extortion threats, and provides guidance to the the software developed for DOE can be readily used and ex-Federal Aviation Administration in cases where aircraft can panded for application to the nuclear power industry. In the potentially intercept radioactive debris clouds from foreign near future, we plan to investigate these expansions through nuclear atmospheric tests.
work funded by the Nuclear Regulatory Commission.
Two ongoing and two proposed studies supported by I. M. H. DICKERSON and P. H.GUDIKSEN," Atmospheric NRC will investigate the applicabil?ty of the ARAC service to Release Advisory Capability (ARAC) Response to the the nuclear power mdustry. Much of the present interest in Three Mile Island Accident," UCRL-83489, Lawrence the ARAC service has been generated as the result of ARAC s Livermore Lab. presented at the IEEE Symposium on participation in the Three Mile Island nuclear accident. Dur-Nuclear Power Svitems rnet.1 A 10 1970) ing that accident, ARAC supported the DOE on scene com-
'"" - ' ' ~
mander by providing guidance on the deployment of ground,
- 2. M. H. DICKERSON, J. B. KNOX, and R. C. ORPHAN.
and to some extent, air monitoring resources, estimating the
" ARAC Update-1979," UCRL 52802, Lawrence Liver-source term, and screening the data for consistency.' After more Lab. (1979).
the accident, the ARAC models were used to provide the
- 3. C. A. SHERMAN, "A Mass <onsistent Model for Wind staff of the President's Commission on the Three Mile Island Fields Over Complex Terrain,"/. Appl. Nercor.17,312 accident detailed person rem estimates for the first nine days (1978)'
of the incident and for distances out to 30 miles from the reactor site. Experiences gained during the Three Mile Island
- 4. R. LANGE, "ADPIC-A Three-Dimensional Particle in< ell accident and responses to approximately 35 other incidents Model for the Dispersal of Atmospheric Pollutants and Its or tests of the system over the past five years have greatly Comparison to RegionalTracer Studies,"1. Appl Mercor.
contributed to the design of the ARAC system as a tool for 17,320(1978).
emergency response planners.
- 3. Perspectives on the Role of Radiological 8
Major components of the ARAC system are: (a) three-dimensional (3-D) numerical models used to provide real.
Monitoring in an Emergency, James A. Martm, time regional (out to 100 km) assessments;(b) a data link to Jr. (NRC) the Air Force Global Weather Central for real-time meteoro-logical data collection; (c) a central facihty consisting of INTRODUCTION minicomputers devoted to data acquisitic.1, analysis, and file This paper addresses the role of radiological monitonng f
building for computer codes; and (d) a site facility. The site in an emergency as an aid in protective action decision mak-facihty is the minicomputer placed at each ARAC-serviced ng in the public domain. The emphasis is on the interpreta-site. These site facilities perform several functions tion of measurements that could be made using simple and abundant instruments, as opposed to necessary or desirable I. Multiplex the environmental sensors.
advances in the statecf-the-art.
- 2. Provide local data quality control.
Projected doses for which protective action would be j
- 3. Continuously calculate and display Gaussian diffusion warranted are called protective action guides (PAGs). PAGs t
estimates for close in distances (out to approximately are defined for specific pathways, radionuclides, body organs.
10 km) using latest local meteorological data.
and protective actions, and range from* I to 25 rem.' A few
- 4. Transmit local environmental measurements to the examples will be used to illustrate that if a PAG were to be ARAC central facility.
realized, monitored radiological variables would be so high that one could use very simple rules of thumb and very sim-
- 5. Receives and displays regional 3-D transport and diffu' ple instruments to sort out hazards from the merely annoying sion calculations
- from the central facility.
or troublesome.The question arises: Would or should author-
- 6. Display a listing of the last four hours of wind and ities plan to await the actuality of a PAG before recommend-temperature measurements for each sensor.
ing protective action? The answer is: For some cases. no This leads to a further question: What is the proper role of
- 7. Display a wind rose of the latest two hours of wind radiological monitoring in an emergen.y? The answer is speed and direction measurements for each sensor.
mixed, but under current NRC guidehnes initial protectise actions would be predetermined for many cases for whwh These site facilities can be considered work stations for the httle or no radioactivity releases would be observed.
emergency response personnellocated at the site of an inci-MINIMUM SOURCE TERMS REQUIRED FOR in addition to meteorological data, radiological data PAGs TO BE EXCEEDED could also be transmitted to the site facilities and integrated For atmospheric releases, the dose commitment is pro-with the capabihty of monitoring and displaying site mete-jected using the basic equation:
orological environmental data. These site facilities, or work stations, become valuable tools for the emergency response D = (x/Q')Q(DF)
I ff*
m m
m Radiation Monitod$g for Emergency Preparedness at Nuclear Plants 728 less elaborate, quicker, aikit not as accushE monitoring ap-where D is the dose commitment in rem, WQ' is the aeolian proach would be to conduct a simple pasture survey with a dilution factor in s/m, Q is the release in cunes, and DF is a thin-window Geiger counter. Derbed emergency action tevels 8
dose factor in units appropriate for the pathway of concern.
'suggest that a child's thyrojiingrstion dose of 15 rem *ould Assuming x/Q' = 10s/m (e g., Pasquill F r.tnihty,10-m be prQected at a contamination level of I to luciof 8821 on 3
release height, 2 m/s wind, no plume meande, no wind sh;ft, and 2-km downwind distance), and setting D equal to the pasture land.2 At this contaminaron level tie gamma dose rate at I m above the pasture would be only about 5 grem/h appropriate PAG for (i.e., within the range ef the natural background dese of 5 to I.the whole-body dose via external clob.d gamma path-15 prem/h). This probsbly would not be resolvable using a Geiger counter, but the contamination could be resolved way (5 rem) using more expensive portable spectrum analyzers. liowever,
- 2. the child's thyroid dose via the ir.halation pathway a survey of the beta actuity at the surfve of the pasture, 8
(15 rem) using a relatively less expensive thin window (7 mg/cm ) de-
- 3. the child's thyroid dose via the milk pathway (15 r:m),
tector, would result in count rates wed in excess of the natural baaground at this contamination bel (e.g., equiva-one can calculate the following minimum source terms (Q) lent tc I to 2 mR/h for an infinitely thin soyce.s necessary to exceed the PAG:
.lf the contamination were to be caured by,a release of a Activit PAG relatively fresh mix of " I through '881, as from an accident Pathway Organ (Ci)
(rem) snvolving a core recchdy at power, the presence of thtother Cloud gamma (1 meV)
Whole body 1,500,000 5
adiciodines wouH. induce much stronger gamma and 6cta ve and on a pasture. Even th? ugh the
'#8I8 IC ""' raks) gI are comparatively short (I day and Inhalation of 88'l Child's thyroid 400 15 half-lives cf i381 and 6.7 h, respectively), in the early time frame their contribu-Ingcstion of ast! vin tion to the gamma dose rate would increase the signal t:y milk Child's thyroid 1
15 about a factor of 10 over that from 88'I alone. Thus, the Slightly different activities would be calculated depending on PAG trip level for protective action nuld be easily observa-the reference used to obtain the dose factors. These calcu-ble using a simple Geiger counter. Confirmation by a beu lated source terms are greater than what would normally be survey of the pasture would be trivial. In fact, pasture cor-tamination w6l below the PAG trigger level should be readily releaseo in a year from a BWR, and over the life of some detectab1>! without the need for laboratory analysis.
PWRs.
Detection of the potential for a PAG to be exceeded via At a light water reactor, only irradiated fuel contaiv 1,500,000 Ci or more of radioactivity, so damage to irradi-,
rr. cat and vegetatte pathwrys would be easily detectable also.
This should be obvious fcr tiz case of the radiciodines, since ated fuel would be necesscry for the cloud gamma PAG to be -
the required initial depositions on pasture would be substan-exceeded. Only irradi.!ed fuel and primary water could con #
tially greater than that for the milk pabway.
tain 400 Ci or more of '881, and only a few other systems '
~
contain ! Ci or more of "8'I. From this perspective, one can CONCLUSIONS identify those few systems that could possibly cause a cose off site in excess of a PAG, and thereby eliminate potential, One can derive other action leMs (chtrvables) related to even catastrophic, damage to many systems from considera-PAGs (not observables) for other pathways, in a sirnilar tion for predetermined protectise actions off site.
fashion. One finds that many derived action hyds s'touM be readily observable using simple instruments. This a3 not too These estimates are also useful for setting emergency surpnsing, considering that the normal dose commitment rate action levels (observables) based on effluent measurements.
for effluents is on the order of I grem/h, whereas a rate close For example, in the early phases of a re' ease, dose commit.
to I rem /h would be required to exceed a PAG in a short ment projections over the next 3 h or so rould be of great period (an emergenen import. Since there are about 10,000 t in about 3 h, mea-A thought provoking trahstion occurs when the implica-sured release rates as low as 150 Cf!s of hud gamma emitters, tions of FAGS are viewed in this light: As a practical matter, and/or 0.04 Ci/s and 10'* Ci/s of '881," projected to be sus-should not protective actions be instituted well before such tained for several hours, could be of serious import for the signals would become so obvious? The answer seems to be cloud gamma, inhalation and milk'mgestion pathways, re-predetermined to be: Yes! If so, of what practical value j
spectively. Since x/Q' is inversely proportional to wind speed, one could tune this a bit by establishing a figure of-would PAGs be in an actual emusency: The answer to this i
merit such as Q'/u, where u is the wind speed. Fos example, is not at all che It wotid be lesFior the public that we Q'/u (Ci/s released per m/s of wind speed) greater than 75 never flN out.
(hard gamma emitters), projected to be sustained for several Meantime, an emergency detettion/ classification /notifica-hours, could be used as a somewhat conservative action level tiodimrtediate action scheme has been developed by the for the whole-body PAG, based on two monitored variables.
NRC which includes an emergency class which would require Using this rule of thumb, a rekase rate of 750 Ci/s of hard the in.tiation of early action based on seque. ices or coinci-gamma emitters, with a wind speed of 10 m/s, would be a dences of events that could if not terminated,cause PAGs to trigger level for protective action. These i: tion levels are so be exceend off site
- Under this concept,immediate,prede-high relative to normal effluents that a p!.nt wou'd have to termined tro:ecive actions would be planned to be initiated, be m very serious trouble indeed for them to b: realized.
fbr such ments, even before significant ernission rates or radiation levels off site would exist;i.e., before there would e
ACTION LEVELS FOR MILK AND be any activity of substance to monitor off site (even on sue,
?
for some cases). This 'act first, monitor later sequence AGRICULTURAL PRODUCfS would be reserved for events of expected low frequer.cy and Plans for monitoring the milk pathway are an important grave -fraport, zW for predetermined low-nsk protutae aspect of emergency plans. Because of its higher dose factoractions (e.g., take shelt:r in place, put cows in the barn).
and half-life, asil receives the most attention. Most plans call C herwk, rad.ological monitonna would precede protective for the collection of either forage or milk for analyses. But a
b
~ /
Radiation Monitoring for Emergency Preparedness at Nuclear Plants 729 action, if any. Radiological mon torkg would play a dom-Outside the plant, monitoring stations are set up nearby inant role for events of lesser import in longer term recovery and as far away as 19 miles. They collect iodme, rainwater, actions and for documentas;on of radiological consequences particle fallout, and moisture. The data from six stations are of accidents of any magnitade.
telemetered to the plant control room, and others are re-
- 1. USEPA, EPA-520ft-79)01,.
corded locally for periodic manual access. Approximately 40 points will be monitored with thermoluminescent dosimeters
- 'Y ""* *
- 2. U.S.H.E.W., F.R. 12-15 78.
ater samples are taken by automatic samplers from the
- 3. Met. and A t Energy-1968. p. 331* SLADE' Ed-discharge to the lake, from three points on the lake, and at the intake of the nearest downstream user. The samples are
- 4. U.S. N RC, NUREG-0610.
analyzed off site at TVA labs.
A health physics team is on call for emergency surveil-lance, not only at the Sequoyah plant but from the nearby 4, Radiation bnitoring at TVA's Sequoyah Watts Bar nuclear plant (scheduled for operation in 1981) and fmm TVA's other offices and plants.They are supported s
Nuclear Pisnt,J. W. Nashburn (TVA) by portable equipment including survey meters, portable air Sequoyah nuclear plant is a power plant scheduled for samplers, air samplers with charcoal canisters for iodine col-commercial 4peration later this 3 ear. This Faper summarizes lection, sodium iodide detestors, and scalers. Radio-equipped the radiation monitoring equipment and facilities planned for vehicles are provided for their use. Backup technical support emergency pr paredness in this facility.
can be helicoptered in from Chattanooga and Muscle Shoals.
Alabama. An all-weather landing pad is provided for the with a total generating capacity of 2574 h, reactor plant helicoptm, end TVA has suitable helienntm on standbv for Sequoyah.is a two-unit pressurized water The reactors emergencies. They can also be used to mo"nitor the plume and were made by Westinghouse.The designer, constructor,own-to ferry samples to off-site laboratories, such as TVA's at er, and operator is the Tennessee Valley Authority (TVA).
Muscle Shoals, a future TVA lab at Vonore, Tennessee, and Tle plant is located on Chickamauga Lake just 15 miles the Oak Ridge Nationallaboratory.
north of Chattanooga, Tennessee. It was originally mtended In addition to the radiochemical laboratory of the for operation in 1973 but has been delayed for various reasons and now has a mixture of newer ar,d older design Sequoyah plant, a Health Physics Unit van is capable of pro-viding analysis of air samples and contamination smear sur-
- features, veys, and the TVA Nuclear Training Center located adjacent For example, the bulk of the m-fant radiation monitor-to the Sequoyah plant has a complete radiochemical lab ingfystems were produced sn 1972 xd are based on analog similar to that at the plant.
eterronic cirents where the ratemetr is physically located in W main control room along with a strip chart or multi.
In summary, the radiation monitoring systems and equip-point recorder. At the monitored location we have assemblies ment provided for Sequoyah nuclear plant began with state-confaming the detectors and preamplifiers. Where local of-the-art equipment in the early 1970's, have been updated rkms are required, these are wired back from the ratemeters throughout the decade and especially since the Three Mile in the control room, which contam the alarm level trip cir.
Island accident, and now represent a suitable complement for safe operation as we view nuclear plant operation in 1980.
cuits.
Plants earlier than Sequoyah have typically utilized in'
- l. "TVA Nuclear Program Review: Sequoyah Nuclear Plant
, line monitors, m which a detector is inserted in a well on the and the Report of the President's Commission on the process piping or directly mto an air duct. Sequoyah has off-Accident at Three Mile Island," Tennessee Valley Authori-kne monitors, to which the sar:iple is piped and, except ty (Nov.1979).
where a sufficient pressure differtntial is available, a sample 2."Sequoyah Nuclear Plant, Final Safety Analysis Report,"
l pump is part of the instrument assembly. The off-line moni.
Vol 9. Tennessee Valley Authority (Feb.1,1974).
(
tors are heavily shielded and perrnit measurement of low 8 83Xe, even in a concentrations, typically 2.3 X 10-' uCi/cm 1 mR/h gamma-ray background. When ambient radiation levels are high, the in-line type of monitor is sometimes in-
- 5. State Radiation Monitoring for Nuclear effective due to the lack of proper shielding-Power Plant Emergency Properedness, Kenneth a
h-Continuous radiation monitors are provided for critical J. Nemeth (So. States Energy Bdl in-plant ventilation systems such as the main control room During the past decade there has been a deepening crisis s
and also for the identifiable relea.;e points where radioactive in state radiation monitoring and emergency response pro-materials may leave the plant. It has been necessary to add a grams. This is true because of the technical nature of the l
l high range effluent monitoring capability since the Three programs and the low priority which the nation's state legis-Mile Island accid?nt last year The new equipment will give latures continue to assign them.
l I>
Sequoyah the ability to measurr'up to 0.1 Ci/cm under accident conditioas. Also, the cor.tainment air will be viewed Often the question is asked at alegislative hearing,"Why by redundant exposure rate detectors looking through the should the state fund such a program when NRC already l
containment wall, capable of measzing up to 10' rad /h in requires th4 the industry maintain a monitoring and emer-gency response program?" The answer often is that the state l
the containment.
is charged with primary responsibility for the health and
(
The major difference between Sequoyah's radiation mon-safety of its citizens. A good system of baseline data gather-ittnng and that of the plants TVA is planning for the mid-ing can ensure that the state is aware of radiation releases, i
1980's is the switch to microprocesrar-based systems and ca,n monitor and track them accordingly, and is ptepared to I
CRT video display for the operatots on the later designs.
mp n to an enwgmcy.
The microprocettor-bas.ed systems are expec*ed to reduce the Education of state legislatures is a key element in devel-crrator's workloai and to improve the dectromagnetic oping any monitoring program for emergency preparedness noise immunity of tye systems.
i I