ML20206H476
| ML20206H476 | |
| Person / Time | |
|---|---|
| Site: | Braidwood  |
| Issue date: | 06/03/1986 |
| From: | Miosi A COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| 1742K, NUDOCS 8606260111 | |
| Download: ML20206H476 (18) | |
Text
__
s Commonwealth Edison one First Nahonal Plaza. Chicago, libnors Address Reply to Post Office Box 767 Chicago. Hlinois 60690 June 3, 1986 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC.
20555
Subject:
Braidwood Station Units 1 and 2 Habitability of Control Room Following Postulated Accidents Involving Shipments of Chlorine NRC Docket No. 50-456/457
Dear Mr. Denton:
We are submitting for your review and concurrence a Sargent and Lundy report entitled " Habitability of Control Room Following Postulated Accidents of Chlorine Shipments in the Vicinity of Braidwood Station" dated May 19, 1986.
Included in this report are results of a survey of industries and transportation routes in the site vicinity which may use, store, and/or transport chlorine.
Two analyses were performed to determine the control room habitability in the event of an accidental release of chlorine.
first analysis, a study of the dispersion of vapor released from aThe postulated accident, and the second analysis, a study of the probability that uninhabitable conditions could be caused by a postulated accident, installed at Braidwood are not required.both show that the chlorine detectors presen If this is found acceptable then we request that chlorine detectors be removed from technical specification considerations.
If you have any questions regarding this matter please address them to this office.
One signed original and fifteen copies of this letter and attachment are provided for your review.
Very truly yours, fh p
1 A
A. D. Hiosi Nuclear Licensing Administrator
/klj encl.
cc:
J. Stevens/'
I p@l
At t aentnant 1 May 19.
1986 Page 1 of 7 i
Habitability of Control Room Following Postulated Accidents of Cnlorine Snioments in the Vicinity of Braidwood Station Introduction Tne licensing of tne Braicwooc Station recuired a survey of industries ano transportation routes in the site vicinity, whten may use, store ana/or transoort chlorine.
The information was tnen used to evaluate the control room habitability at the Bratowooo Station.
One suen survey, conducted in 1983, revealeo snat, on tne easis of weight and shipping frecuencies provicea in Aegulatory Guice 1.78 for cifferent modes of transportation, eniorine was transportea above the frequency requiring analysis only on tne Norfolk & Western Railroaa near the site.
- However, no further analysis was conducted to determine if uninhabitable concitions in tne control room could be caused by accicents involving rail tana cars containing chlorine.
Instead, to exoecite tne 12 censing of the plant, redundant chlorine cetectors were provided on each outside air intake of the control room.
A new survey was conducted in February-May 1986 to supplement the information obtainec from the 1983 survey.
The purpose of this stucy is to provide a control room habitacility analysis of the Braidwood Station control room due to accidental release of enlorine transoorted on the Norfolk & Western Railroad line.
Two distinct types of analyses were performed.
The first analysis considered the dispersion of the vapor released from a postulatec accioent to the station and subsequent infiltration into the control room.
Tnis analysis utilized the normal air exchange rate of the control room based on the design makeup air and tne control room volume.
The second consistec of a ceterrninat ion of the crocacility that uninhaoitable conditions in the control room coulo be caused by accioents involving rail tank cars containing enlorine.
The orobability analysis considered the stattstical cata for rail tank car accioents ano the meteorological carameters, based on wind direction and atmospheric stability, coulo cause the development of toxic concentrations tnat in the control room.
A description of the control room HVAC system is oresented in the Braidwood Final Safety Analysis Report (FSAR)
Section 6.4 and is briefly presented here.
The following discussion describes the Regulatory Guides whien form the basis of the control room habitability evaluation, the result s of two surveys, and the analysis regarding evaluation of chlorine as a hazard to the Braidwood control room.
Based on the information collected to cate, it is concluded that no special protection provisions are recuired at the Braidwood Station.
Control Acom HVAC System Descriotion Two redundant HVAC eouipment trains with commen supply and exnaust euct ano duct accessortes comprise the control room HVAC system.
Air in the control room is supplied from recirculated air f rom wa tn an tne control room envelooe and mixed with makeuo
. ~
7-1 Attachm2nt 1 May 19, 1966 page 2 of 7 air from the outside air intake or the turbine building air
\\
i intake.
With turbine building intake, the makeup air is filtered through the emergency filter units.
The outside air intake is useo for makeuo air curing normal plant operation.
Normal coeration of the control room HVAC system is shown schematically in Exhiott 1 (Reference 1).
1983 Survey of Cniorine Shioment The FSAR Section 2.1.1 descrioes tne location of the olant site and the transoortation routes near the site.
The FSAR Section 2.2 describes the nearby industrial, transportat2on, and military facilities.
The industries that use, manufacture, or store enlorine witnin amoroximately 15 miles of the Braidwooo Statzon were surveyed to determine frequency of shipment and mooe of transoortation.
The survey revealeo (Section 2.2.1) that only two toxic chemicals were shippea regularly on Highway 55:
denatured alcohol and methanol.
It was determined from the toxicity levels of both enemicals that neither presented a hazard to the Braidwood Station.
Additionally, the survey revealed that toxic chemicals were transporteo on the Norfolk & Western Railroad and the Atch2 son, Topeka anc Santa Fe Railroad.
An analysis was done for all toxic chemicals shipped on both railroads.
All chemicals except for cMlorine were eliminated, on the basis of weaght, shipping frecuency, and the diffusion model provided in Regulatory Guice 1.78 as hazards to control Since the control room hanitability.
room was equipped with chlorine detectors in tne control room HVAC system intake air ducts, no further analysis for chlorine was conducted.
L986 burvey of Cniorine Snzoments To supplement the 1983 survey and to obtain additional snformat ion on chlorine sna oments, a survey was conducteo during February-May 1986 to determine if chlorine is transported on the railroad Innes and Highway 55 passing within fsve miles of the Braidwood site.
For this survey, information was obtained from the Chlorine Institute, a national trade organization with headquarters in New York, whose members are mostly chlorine producers.
The Institute carries out research, produces literature, and in genwral, maintains the most up-to-date information on chlorine in the United States.
Additionally, industries previously contacted in 1983 were contacted again to cetermine if these industries used, stored or transoorted chlorine on Highway 55.
According to the Chlorine Institute (Reference 2), only about 1% of chlorine shipped in the U.S.
is transoorteo by trucks.
Of this 1%, only a small portion would be transoorted by tank trucks, and these are mainly owned by water and wastewater treatment plants that operate these tank trucks for their own use.
The Chlorine Institute further stated that
{
there are no chlorine manufacturers in Illinois nor Missouri, but tnere are three in Wisconsin.
Two of the Wisconsin producers use j
4ttaenmsnt 1 May 19, 1986 page 3 of 7 all the entortne tnev oroduce.
The third oroducer is located in Port Eowaros, wnien coes not snio enlorine in the Northern 1111nois atea anc does not use semi-trailer tank trucks for any of its sniements (Reference 3).
Several of the surrounding municioalities (witnin 10 miles of the plant) ano some of tne sarcer coeulation centers witnin a 30-mile radius were surveyed regarotnc Enear use of chlorine in water and wastewater treatment olants.
Exntoit 2 lists the towns / cities surveyed and tne information proviceo my tne appropriate personnel.
FSAR Tacle 2.1-10 and Figure 2.1-8 orovide the oopulation ano location of tne towns / cities listeo in Exnibit 2.
Tne information gathered from individual municipalities indicates tnat tnere are no chlorine containers larger tnan one ton used for water or wastewater treatment in the vicinity of the Bratowooo Station.
The majority of the facilities receivec enlorine in 150 pound cylinders.
Distributors of chlorine oeliver ootn 1 ton containers and 150 pound cylinders by truck to tne treatment olants.
In addition to municipalities, four major cistricutors of enlorine, three in Illinois and one in Indiana, were surveyeo about enlorine truck shioments.
All stated that enlorine shioments using trucks were in either 150 pound cyllncers or i ton containers.
According to one distributor (Reference *),
chlorine is usually delivered from the producer using rail cars anc then cumped into 1 ton containers or 150 couno cylincers.
According to this source, semi-trailer tank trucks are not used anywhere in the U.S.
for chlorine shipment.
Regarcang chlortne snipments on the railroads, appropriate eersonnel of tne Illinois Central Gulf Railroad (ICG), the Atensson. Topeka and Santa Fe Railroad (AT&SF), and the Norfolk &
1 western Railromo were contacted.
According to the ICG, no toxic enemicals are snipped on its two segments of railroad wntch pass witnan five miles of tne Braidwood site (Reference 5) ano the total numoer of chlorine earloads on the AT&SF were only 4 and O
)
durino 1984 ano 1985, resometively (Reference 6).
Tne 1986 survey revealed that, on the basis of weight and sniocing frecuencies orovided in Regulatory Guide 1.78 for cafferent modes of transoortation, chlorine was transported above the frequency requiring analysis only on the Norfolk & Western Railroac.
In order to pseform the dispersion and probability analyses, enlorine snipment data (number of railroad cars and maximum tonnage of chlorine) for the years 1983, 1984, and 1985 were obtained for the Norfolk & Wertern Railroad.
1 l
l --
May 19, 1986 Page 4 of 7 Discersion Analvsis and Control Room Infiltration in Accordance witn Regulatorv Guide 1 7R 2
Tne accioental release considered in this analysis is the comolete rupture of a rail tank car containing 83 tons of liculfied enlorine wnien instantly releases its contents.
Cnlorine is stored as a liquid under pressure.
Upon release, accroximat ely 25% flashes immediately to vapor.
The remainoer as a licuid at -3O o F, which gradually bcils off by transfer of heat from sne environment.
Tnis scenario is based on Regulatory Guice 1.78 ano 1.95 (References 7, 8).
The flashed vapor constitutes tne orancipal nazard to tne station.
The cisoersion ano cropagation to the Braidwood site is predicted in accordance witn metnoon oescribed in Regulatory Guide 1.78.
The stability class considereo is pasouill, Type F, which results in control room concentrations wnsch would be exceeded in less than 5% of all occurrences.
Exnioit 3 describes the basis of the analysis and the results.
The control room air exchange rate used in the analysis was that of a control room in the non-isolated mode (Type C classification per Regulatory Guide 1.78).
Exhibit 4 shows the results of oiseersion analysis as the rise in concentration with respect to time.
According to this analysis, the personnel of the control room can avoid exoosure to toxic concentrations of chlorine if an aoprooriate response is mace within two minutes of the time the cresence of enlorine can ce detected by its odor (3.5 ppm).
Tne response may be the donning of air masks.
The toxic level is 15 com.
Tne maximum concentration (13.3 pom) shown in Exhioit 4 1s the concentration ex1 sting 2-minutes af ter the presence of the enemical in tne control room cecomes noticeable by its ocor to cersonnel.
Tne cesigna, tion maximum is used since the analysis consicers various winc speeds and the value given is tne hignest value obtained witn all wind speeds.
prooanility of Causino Uninhaoitaole Conditions in the Control Room due to the Ruoture of a Chlorine Tank Car on the Norfolk &
hystern Railroad i
Since the dispersion analysis showed that the chlorine concentration (13.3 ppm) was ouite close to the toxic concentration (15 pom), a probability calculation was performed.
1 The Standard Review Plan (SRP) and Regulatory Guide 1.70 provide i
criteria for acceptance based on probability calculations (References 9, 10).
Section 2.2.3 of the SRP providns, criteria for ceterminino if a toxic release need be considered a design casts event.
Soecifically, it states:
The crocability of occurrence of the initiating events leacing to potential consequences in excess of 10 CFR part 100 exoosure guidelines should be estimated using assumotions that are as representative of the specific site
At t ae n rnPr.t 1 May 19.
1966 Page 5 of 7 as is oracticaole.
In acoitton. because of sne low orocao111 ties of tne events unoer consideration. cata are orten not ava11aoie to permit accurate calculation of crocao111stes.
Accoroingly. sne exoected rate of occurrence of morential exoosures in excess of tne 10 CFR Part 100 guicelines of aooroximately 10 -6 per year is accootaole af, wnen comoineo witn reasonsole cualitative arguments, the reaststle o*ocaollity can ce snown to De lower.
A orocaollity calculation was cerformeo for chlorine sn a pment s on tne Norfolk & Western Railroad line in tne vicinity of Bratowooo Station.
Tnis orocapility was calculated by the following mornoo.
Statistical meteorological data (Table 2.5-25 of tne FSAR) for tne Bratowood site (30-foot level) were useo whien consisted of occurrence probabilities of stability class anc wino magnituce.
The procacility that the control room could be made unannacitaole was calculated from three orobable events
- 1) the orobability that an accioent could occur within each sector; 2) the orocab111ty that the wind has a direction which would carry released vapor to the control room, and 3) that the stability class would be F or G.
A diffusion analysis in accorcance with Regulatory Guide 1.78 and 1.95 showed that only a G stability class woulo result in uninnabitable conditions (toxic concentrations of 15 pom two minutes after detection by odor) in tne Bralewood control room due to rupture of an 83 ton rail tank car on the Norfolk & Western Railroad line.
Since the F stacility class snowed habitable conditions only by a small margin. It was also included in the probability analysis.
Only sne cortion of the railroad within a distance of 5 miles from tne station recuired consideration in this analysis according to Reoulatory Gulce 1.78.
Tne following calculation was cerformeo:
3 Pr(C) x F (C) x IL(D) x Pw(D)
(Ecuation 1)
Pa
=
D=
1 Wnere Da = orocability of accident resulting in control room uninhabitability
[ releases]
[ year 3
orobability of release Creleases]
Pr(C)
=
[carmile 3 frecuency of shioment
[ cars]
F(C)
=
Cyear]
length of track under consideration (miles)
L(D) =
,, - ~., - - - -
Attaenment 1 May 19, 1986 Page 6 of 7 oronactitty tnat unoer F ano G stability classes, PwtDs =
wino is crowino in a otrection suen tnat a enemical release is carrieo towaro the control room air antaxe sDamenstonless). D is tne airection from wnsen tne wino is olowing (See Exniott 5) ws snown in Exntoit 6.
cniorine (classifieo as a non-flamtnaole oass nas accioent treleases frecuencies oft
-6 cc,1,..
s3 0.019 x 10 wests =
Ecarmile 3 ine foilowing entorane snioment data were obtained for the Nortois & Western Railroaa line (Reference 11):
Year Carloads of Chlorine 1983 36 1964 49 1985 24 As snown in Exhioit 7:
3 0.04939 (miles)
EL(D) x Pw(D)
=
D= 1 Assuming 49 snioments/ year, ano using Equation (1), the oromaollity of chlorine release is
-6 Pa = 0.019 x 10 sreleases] x 49 Ecar J x 0.04939 (miles)
Cearmile ]
Cyear]
10 ~0 Creleases)
=
- x C
year 3
ine use of this orobability assessment is conservative and the realistic crobability can be shown to be even lower because of tne following conservatisms:
A.
No credit was taken in the accident release pecbabilities for tne improvec safety frorn recent tank car modifications such as a tank head puncture resistance system.
The accident release probability data were from 1971-77 statistics before the tank car modifications becarne mandatory.
c.
No creoit was taken for coerator incapacitation events tnat woulo not result in exposures in excess of 10 CFR 100 outoellnes.
This analysis assumed all such events resulted in overewoosure.
Only one out of ten operator incaoacatation events would result in an overexposure (Reference 12.
13).
r
- e Attacnmsnt 1 Play 19, 1986 Page 7 of 7 As snown in Exntoit 6.
tne numoer of chlorine railroso car sntoments is 1065 cer year for an exoosure rass of 10 -6 >yr, f
Gonqiusion On toe casts of weignt ano snieoino frecuencies orovioeo in wegulatory Guice 1.76, enlorine is shlocea on the Norfol< &
western Ra11roac line ano tne maximum number of enlorine railroao cars sniooeo curing 1983-1965 on the Norfolk & Western Railroaa 41ne is recorreo to De only 49.
Hnalysis of tne control room nacitaollity in accordance witn Heaulatory Guice 1.78 snows tnat tne enlorine concentration in tne control room coes not reacn tne toxic level 2 minutes after tne cetection oy its ocor.
Since tne analysis snowed haoitaole conoitions only oy a small margin, a probability analysis was cerformeo wnien snowed that the Braidwooo Station control room as nacitaole for an exoosure risk of 10 -6 per year for uo to 1065 sniements of enlorine on tne Norfolk & Western Railroad line.
Tnis orobability is snown to be even lower when qualitative assumotions are taken into account.
Tne results of these two analyses show that chlorine detectors are not reouirec at the Braiowood Station.
It should be noted tnat in accorcance witn olant emergency plans and procedures, self-containino creatning aooaratus is provided for assurance of control room nabitability in the event of possible detection of cnlorine ano smoxe cue to accicents.
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- References 1.
Commonwealen Ecison Comoany, Byron /Braiowooo Station Final darety Anaivsis Recorr. Volume 6.
Section 6.4.
d.
R.
mitenell. Chlorine Institute. New York, Personal Communt-cation witn Saroent & Luncy. Maren 11, 1986.
3.
Cnaries williams. Transoortation Manager. Vulcan Cnemical Comoanv. Personal Commun2 cation witn Sargent A Lunoy, May 19.
1986.
Valley Cnemical Comoany, Personal Communication witn Sargent & Luncy, May 16, 1986.
S.
w.
Garaner, Superintencent of Transportation, Illinozs Central Gulf Railroad, Personal Communication with Sargent & Luncy, Maren 5, 1986.
6.
L.
Zancer, Atchison Topeka and Santa Fe Railroad, Personal Communication with Sargent & Lundy, March 5, 1986.
7.
U. S.
" Assumptions for Evaluating the Habitability of a Nuclear Power Plant Control Room During a Postulated Hazardous Chemical Release."
8.
U. S.
" Protection of Nuclear Power Plant Control Room Doerators Against an Accidental Chlorine Release."
9.
U. S.
NRC Standarc Review Plan, " Evaluation of Potent 2al Accacents," Section 2.2.3 NUREG-0800, Rev.
2, July 1981.
10.
U. S.
NRC Regulatory Guide 1.70, "Standarc Format and Cont ent of Safety Analysis Reoorts for Nuclear Power Plants",
Sect 2on 2.2.3.1.
11.
Norfolk & Western Railroad, Mr.
G.
Walker, Personal Communication with Sargent & Lundy, February 14 and 27, and March 21, 1986.
12.
D.
E.
- Bennet, D.
C.
Heath, NUREG/CR-2650, SAND 82-0774 R4 "Allowaele Shioment Frecuencies for the Transport of Toxie Gases Near Nuclear Power Plants" Prepared by Sandia National Lacoratories, October 1982.
13.
Ducuesne Liont Comoany Report to NRC " Beaver Valley Power Station Control Room Habitabilzty," December 28, 1981.
24, 4 letter cateo Aoril 1,
1986 from A.
D.
Miosa (Commonwealtn Ecison Company) to H.
R.
Denton (Nuclear Regulatory Commis-ston). Rost-Aceicent Control Room Maettability Analysis for Bratcwooo Station.
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4.
\\'a v a d W"e Q D.
W.
Yalmer. "1ssues arsO D1 rne res l ores r;s f E t't91 C o t Car Si:::e:
A CoMDenol urd. "
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De Dart rnent of
'ransoortatlor. Geoeral Aaiircao Aorn1rsist rat lore r't e oor t No.
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may 19, 196E Page i ef :
OLDAlt BEE in dTER AND mASTEATER TREATE.hi FACILITIES OfERATED BY T(Eddi/ CITIES mITHI410 RIDS ibid 30 aldS (F T4 BfWII" STATI(k mITain 10 aldS IdlTEA T U T O T IdETElflTD TUTIENT Iranomoco 100 les cylinoers (gas) 55 gallon arms (liquid)
Coal City (including Elisen) 150 lbs cylinsors (1io 1o)
+
kaceville 150 los cy! velers (liosid)
Esrowr ha(DCl) 150 lbs cylinders (liontd)
So6tn Wilmington ns(OCl) 150 lbs cylinders (liosid)
WITHI4 30 MILES Discago Na(OCl)
I ton contaiers (liquid)
Joliet 150 lbs cylinders (liosid)
I ton containers (liosis) enkanse I ton contaiers (liquid)
I ton containers (ligeid) tourtonnais e
150 Its cylinders (ligeid) kaoley e
1 ton contaturs (lisoid) ilassoville 150 lbs cylinders (liquid) 150 lbs cylinders (liquid)
Loctoort 150 lbs cylinders (liquid)
I ton contairers (licend)
Crest Hall 150 lbs cylinnors (liosid) 150 lbs cylinders (liquid) eno treatment facility. snares facility, or no entorane used.
- ~~
Exhibit 3 May 19, 1986 Page 1 of 1 CONTROL ROOM RABITABILITY ANALYSIS Material Spilled liquified chlorine Weight 83 tons Distance from Control Room 4.5 miles Atmospheric Stability Class F
Ambient Air Temperature 90*F Concentration Detectable by Odor 3.5 ppm Toxic Concentration (2 Minute Exposure) 15 ppm Maximum Concentration at Braidwood Site 378 ppm Maximum Cencentration in Control Room 13.3 ppm 2 Minutes After Detection 3
Control Room Makeup Air 6000 f t 7, 3
Control Room Volume (Reference 14) 405164 ft Wind Speed Causing Maximum Concentration 6.15 mph in Control Room after 2 Minutes
^
Exhibit 4 M y 19,1986 i
Page 1 of 1 20 15 Toxic concentration k
120 seconds o
y 10
-.c U
u o
e O
w<ae 5
w Mcou Detectable by odor co U
O i
i e
i 2500 2550 2600 2650 2700 Time elapsed after spill, seconds Concentration in control room after 83 ton spill of chlorine at 4.5 miles 6
l
Exhibit 5 May 19, 1986 Page 1 of 1 Control Room Norfolk Western
,e Railroad 4,
Line f@
ESE SE SSE Schematic showing relationship between the Norfolk f. Western Railroad Line, WIND Sectors and the Control Room
Exhibit 6 May 19,1986 Page 1 of 1
~'
ACCIDENT FREQUENCIES PER MILLION CAR-MILES FOR HAZARDOUS MATERIALS COMMODITIES DAMAGE THRESHOLD 50
>$100
>S5000 Explosives 1.30 0.63 0.210 Non-Flammable Gas 1.00 0.15 0.019*
Flammable Gas 0.94 0.20 0.094 Flammable hiquid 1.20 0.32 0.110 Flammable Solid 0.69 0.17 0.058 Oxidizer 1.60 0.66 0.069 Organic Peroxide 1.40 1.40 Toxic 1.10 0.43 0.079 Radioactive 3.00 1.30 0.420 Corrosive 2.50 0.45 0.090 All Hazardous Material 1.40 0.33 0.086 j
- chlorine is classified as a non-flammable gas.
'aterials Transportation Board Data SOURCE:
M 1971-1977; Arthur D. Little, Inc., Estimates.
Excerpted from U.S. DOT FRA/ORD-79/56 (Reference 9).
.--,------..-..-w.,.--.,
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Exhibit 7 May 19, 1986 Pign 1 of 1 CONTROL ROOM RISK ANALYSIS FOR SHIPMENTS OF CHLORINE ON THE NORFOLK AND WESTERN RAILROAD LINE Length of Railroad Summation of F and G Probability of occurrence section length stability class proba-(All wind speeds for within five miles bilities multiplied Wind F & G stability classes) of site by section length Sector Pw(D)
L(D)
L(D) x [Pw(D)
+ Pw(D)]
F G
ESE O.0079 0.0043 1.63 0.01989 SE O.0084 0.0045 1.87 0.02412 SSE O.0090 0.0038 0.42 0.00538 3
IL(D) x Pw(D) 0.04939 (miles)
=
D=1 W
O
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Exhibit 8
)
l M:y 19, 198.
l Page 1 of 1 ;
j NUMERICAL EXAMPLES OF RISK EXPOSURE LEVELS l
~
Number of Shipments Control Room of Chlorine per Year Exposure Risk i
49 4x 10-8 10-7 106 1 x 10-6 1065 1 x O
' ' * '~~
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_ _ _