Regulatory Guide 1.3

Assumptions Used for Evaluation the Potential Radiological Consequences of a Loss Coolant Accident for Boiling Water Reactor

ML13350A383
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Issue date:	06/30/1973
From:	US Atomic Energy Commission (AEC)
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RG-1.003, Rev 1
Download: ML13350A383 (12)

.!a 1 Revision P Revision I

June 1973 U.S. ATOMIC ENERGY COMMISSION

REGULATORY

DIRECTORATE OF REGULATORY STANDARDS

GUIDE

REGULATORY GUIDE 1.3 ASSUMPTIONS USED FOR EVALUATING THE POTENTIAL RADIOLOGICAL CONSEQUENCES

OF A LOSS OF COOLANT ACCIDENT FOR BOILING WATER REACTORS'

C. REGULATORY POSITION

S.'i'Cllil 50..;,I *it fII('FR PlaII 50( eiliuir lsth:t each I. aIlle

,ssutllptiotis elatied I ll lte tcle:se o' l;ldia:lct ii

1pl'icailll l a ,oittllrlic t n lpli ilil ltm or olperaling lic*tise iilellit l front1 th11f0 I andlcollt iilnltiill alle ;as I",lfows:

'ro',idtc an :!lhlvsis mtid evahaltion ol" the design and a. "\'i- t l >y-f'ive percent, of tile equilih)iilutn pl' ci; Iiiice of1 sitlicitlres. s*:{;ems anld Components of radioactive iodine invetn tory dovelo*.ed fromt mia\ iliintt ihtc I:,,iility with the otive t" assessing the risk to  !'uitl pow'er opeiatioi of thie core slhuhld IV JssI.niCId 1)

lputllic h10:1tll :aitd :lfelv- resl frm Im oporation, ol'the he imtncdililely available I'Mti leakaue fioin the primar:iyv laTilily. "h" de:;ipi basis loss (of' coolant accident reactor conttaiinment. Nine tV-mit percent ito this 2 l()C' A i5 )IliC ,I I p[st lat3ted accidents used 1o perceill is toIle assulmled ito he ill tile 'orto of'ei nlenial evaluate fil ade(l'iacv ofi these Sliltctures. syll.*y s. and iodine. 5 percent of' this 25 percent ill ilic ltOnn oI

c..'tIIIpolt0elli swill lrespecl It tile public health a*nd safely. particulate ioidine. and -I p't.eent of this 25 percinti it!

This Inidle -,i\'es :,ccepltble assumlptions lhat mavy be lhe l'orit of' orwanic iodides.

iseal ill eva\tial l- tihe radiological ctnsequcuces of' this h. One hluldred percent o1' the eqLlihibritinlt accident for a boiling wlei leactor. Ill soniLC CLasCs, radioaclive nhble gas itnVentorny developed Ir'omll ntiitsnltal site chlaractelrisltics. plant dest;i featlres. or IltaxitiltilM frill powver o**ralion of' [lie %:oieshould ble othlr li'l tolls nav:y retqglire dilferetit asstinlotionls w\hich assumed it) lb ietltedialtelv available lot hcakane It'oit wiill ble Ctiside Led on anl illtividulial case basis. The tle leactol Coll lailllltent.

Advisoty ('Cimmnitee Oil Reactor S:ile'quards hias been. c. The elfl*f os . tf' radiolo-ical deca, during holdup consul ted con:ernini lt is guide altnd has conceturred in tlie inl thle conwaiintient or othet bujildimes should ble taketn regulatorvy pl ýili inl. into accounltI.

d. 'File reductiotn ill (hle alotii titt' adioactive

B. DISCUSSION

mtat.'rial :ivailfable for leaka! ito the ehnvironineut bv Arler reviewtitt Cloln[;,ilmllelln Spray'. recirtuilaing filter sys*cnis. ni olhier a titinumber or" applicationls for conslitiet iin ,t nuits mnd opetating licenses for boiling eneih:eered sai'eity ftatlres mtay be takelil itlno :icclittl, water p*,,\er reacolos. tile AEIC Regulaltury staff has bill the atounit of' reduction ihi concrentiation of radioactive materiils shotuld be evtlualed on :an developed a rilniber ofl' appropriately conservalive ildividual case ba:sis.

al, ptinons. bliscd on en&inecring juidpneni and on e. Tile primary conllaitnitent should ble assumed to applicable eXperimnenltal results fromn sa 'ty research leak at the leak rate incorporated or tio hie incolporated progratus cndudcted by the AEC and(l tie nuclear in thie technical specifications f'or the duration ill' [lie industryv. that are used ti) evaluale calculalions of tlie accident. 2 The leaka*e shotild be assuiitedito pass radiological consequetces of1 various postulated accidelel s. t"'l'iS guiidte is a revision *l'ltirrittr Sate \l Giuide 3.

2

'lic e*t'ition containni ent leakaee Iindcr atccid.nl This guide lists acceptable assumptions that may he u-sed to evalutate the design basis LOCA of' a Boilinlg conditio ot" I'e:ttlires protvidted to red ilce t' t':lkatpie of"

radioalclive rtatlritits I'roll ItI" t'(l tnlit1inn n Will he'11CeV3 litt1 Lilt Wa enr Rcactor (IIWPR). It should be shown tlhal tlhe :nilindividual case I*saiis.

of*lsi tc.,lose cotnsequences will be within the guidelines of I(I CFR Part 100.

USAEC REGULATORY GUIDES Copies of published guides may he obtained by reqcuest indicating the. divisions deilred to the US. Atomic Energy Commisvon. Washington, D.C. 201545.

Rcgulatnry Guides are issued in describe and make available to the public Attention; Director of Regulatory Stalndards. Comments and suggestion% lot methods accptablte to the AEC Regulatory staff of implementing specilit part- of itiproverienti In theta guidemý aceancouragd and should be sent to the Secretary the Corirmisl*on' regulations. tO delineale techniques used by the staff in of the Commitsion, US. Atomic Energy Commission. Washington, D.C. 20545.

ealuating specific problems or postulated accidents, or to provide guidence to Attention: Chief, Public Proo-redinga Staff.

applkOjlnts. Reoualo.yi Guides are not substitutes for regulations and compliance with them is not requited. Mrthods and solutions different from those set out in The guides are itsuedt in the fortlowing ten broad divisior.:

the u.-ris will be acceptahle it they provide a basis for the findings requisite to the llluance or osntinuance of a permit or licante by the Commission. 1. Power Reactors

6. Products

2. Research and Test Reactors 7. 'Transrptortation

3. Fuels and Materials Facilities B. Occullationl Heialth PuhllshM quiewi will hbe revi-id periodically, as aip!iogilate. to accommodate 4. Environmental ard Siting 9. Antitrust Review cornrmenit 4nd in reflect new informatint, or experience. S. Materials and Plant Protection tO, General

---

I *

directly to the emergency exhaust system without d. The iodine dose conversion factors are given in mixing' in the. surrounding reactor building atmosphere ICRP Publication 2, Report of Comtmittee i1.

and should then be assumed to be released as an elevated "Permissible Dose for Internal Radiation." 1959.

plume for those facilities with stacks.4 e. External whole body doses should be calculated f. No credit should be given for retention of using Infinite Cloud" assumptions. i.e.. the dimensions iodine in the suppression pool. of the cloud are assumed to be large compared to ihe distance Ihat Ihic gamma rays and beta particles travel.

2. Acceptable assumptions for atmospheric diffusion "Such a cloud would be considered atn infinite cloud for and dose conversion are: a receptor at the center because any additional (gamma a. Elevated releases should be considered to be at andi beta emitting material beyond t(le clotud a height equal to no more than the actual stack height. dimensions would not alter the flux of Igatmna rays Certain site dependent conditions may exist, such as andl beta particles to the receptor" (Meteorology and surrounding elevated topography or nearby stnictures Atomic Energy, Section 7.4.1.1-editorial additions which will have the effect of reducing the actual stack made so that gamnma and beta emitting material could be height. The degree of stack height reduction should be considered). Under ihese conditions the rate of energy.

evaluated on an individual case hasis. Also. special absorption per unit volume is equal to the rate ortenergy meleorologicaI and geographical conditions may exist released per unit volume. For an infinite uniform cloud which can contribute to greater ground level containing X curies of beta radioactivity per cubic meter concentrations in the immediate neighborhood of a the beta dose in air at the cloud center is:

stack. For example. fumigation should always be assumed to occur: however. tlh- length of time that a D. = 0.457 E

rumigation condition exists is strongly dependent on geographical and seasonal factors and should be The surface body dose rate from beta emitters in the evaluated on a case-by-case basis." (See Figures I A infinite cloud can be approximated as being one-half this through ID for atmospheric diffusion factors for an amount (i.e.. 01D- = 0.23 EOX).

elcvated release with fumigation.)

b. No correction should be made for depletion of the effluent plume of radioactive iodine due to deposition on the ground. or for the radiological decay For gamma emitting material the dose rate in air at the of iodine in transit. cloud center is:

c. For the first 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />, the breathing rate of persons offsite should be assumed to be 3.47x 10' DA= 0.507 E rX

cubic meters per second. From 8 to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> following the accident, the breathing rate should be assumed to be

1.75 x 1 0 4 cubic meters per second, After that until the From a semi-infinite cloud. the gamma dose rate in air end of the accident, the rate should be assumed to be is:

2.32 x 10-4 cubic meters per second. (These values were developed from the average daily breathing rate 12 x 107 S=o.2s Ex cm3 /dayl assumed in the report of ICRP, Committee

11-1959.) Where D= beta dose rate from an infinite cloud (rad/sec)

DE= gamma dose rate from an infimite cloud

3

1n some c-ases, credit fur mixing will he allowed: however. (rad/sec)

the amount of credit allowed will be evaluated on an individual EO = average beta energy per disintegration case basis. (Mev/dis)

Ei = average gamma energy per disintegration

"Credit for an elevated release should be given only if the pitnt of release is (I) nire than two and one-half times the (Mevldis)

height of any structure close enough to afrect the dispersion of X = concentration of beta or gatnma emitting the plume, or (2) located far enough from any structure which isotope in the cloud (curie/mr3 )

could have an efrect on the dispersion of the plume. For those It\R's without stacks the atmospheric diffusion factors f. The following specific assumptions are assuming pround level release given in section 2.h. should be used to determine site acceptability. acceptable with respect to the radioactive cloud dose calculations:

For sites located more than 2 miles from large bodies of (I) The dose at any distance from the reactor water such as oceans or one of (the Great takes. a fumigation should be calculated based on the maximunm condition should be assumed to exist at the time of the accident concentration in the plume at that distance taking into and continue for one-half hour. For sites located less than 2 miles from large bodies of water, a fumigation condition should account specific meteorological, topographical, and be assumed to exist at the time of the accident and continue for other characteristics which may affect the maximium

4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />. plume concentration. These site related characteristics

1.3-2

must be evaluated on an individual case basis. In the case (3) The atmospheric diffuision model' for an of beta radiation, the receptor is assumed to be exposed elevated release as a function of the distance from the to an infinite cloud at the maxinmum ground level reactor, is based on the information in the table below.

concentration at that distance from the reactor. In the case of gamma radiation, the receptor is assumed to be Time exposed to only one-half the ckud owing to tcie Following presence of' the ground. Tile maxinmm cloud Accident Atmospheric Conditions concentration always should be assumed to be at ground level. 0-8 hours See Figure 1(A) Envelope o1" Pastluill

(2) The appropriate average beta and gamnia diffusion categories based oil Figure A7 energies emitted per disintegration, as given in the Table NI 'teorolog' and Atomic I-netryo I tt(,1 ,

of Isotopes. Sixth Edition, by C. M. Lederer. J. M. assuming various stack heights: vindspeed I

Hollander, I. Perhlan; University ofCalifornia. Berkeley: me ier/see; uniform direction.

Lawrence Radiation Laboratory: should be used.

g. For BWR's with stacks the atmospheric 8-24 hours See Figure ItB) lEnvelope of Pasquill diffusion model should be as follows: diffusion categories: windspeed I meter/see:

(I) The basic equation for atmospheric variable direction within a 22.5 sector.

diffusion from an elevated release is:

1-4 days See Figure I[C) Envulope of Pasquill

2 2 diffusion categories with the following exp(-h /2Oz ) relationship used to represent maximnnumn Tu y VQ plume concentrations as a tumeltion of'

0z Where distance:

Atmospheric Condition Case I

x = the short term average centerline value of the ground level concentration (curie/meter 3 ) 40Y Pasquill A

601'} Pasquill C

Q = amount of material released (curie/see)

u = windspeed (meter/sec) Atmospheric Condition Case 2

50% Pasquill C

Gy = the horizontal standard deviation of the 50Y%* Pasqtill D

plume (meters) [See Figure V-i. Page 48. Atmospheric Condition Case 3 Nuclear Safety, June 1961, Volume 2. 33.3',` Pasquill C

Number 4, "Use of Routine Meteorological 33.3% Pasquill D

Observations for Estimating Atmospheric 33.3% Pasquill E

Dispersion," F. A. Gifford, Jr.) Atmospheric Condition Case 4 z= the vertical standard deviation of the plume 33.3!, Pasquill 1)

(meters) [See Figure V-2. Page 48, Nuclear 33.3, Pasquill E

Safety, June 1961, Volume 2, Number 4, 33.3K- Pasquill F

"Use of Routine Meteorological Atmospheric Condition Case 5 Observations for Estimating Atmospheric 50r', Pasquill D

Dispersion," F. A. Gifford, Jr.) 501? Pasquill F

h = effective height of release (meters)

wind speed variable (Pasquill Types A. B. E.

and F windspeed 2 memer/sec: Pasquill

(2) For time periods of greater than 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> Types C nid D windspeed 3 meter/sec)

the plume from an elevated release should be assumed to variable direction within a 22.5" sector.

meander and spread uniformly over a 22.50 sector. The resultant equation is:

4-30 days See Figure I(D) Same diffusion relations as given above- windspeed variable dependent

2.032 exp(-h2 /2oz 2 ) on Pasquill Type used; wind direction 33.3"

x/Q frequency in a 22.50 sector.

=

11This model should be used until adequate site Where meteorological data are obtained. In smote cases. avaitable information, such as meteorology, topography and geographical x = distance from the release point (meters); location. may dictate the use of a more restrictive model to other variables are as given in g(1). insure a conservative estimate of potential offtsite exposures.

1.3-3

I

h. For BIWR's without stacks dhe almospheric 2.032 diffusion inodel6,should be as follows: X/Q = azUX*

(I) The 0-8 hour ground level release concentrations may be reduced b'y a factor ranging from one to a nlaximum of three (see Figure 2) for additional Whe re dispersion produced by the turbulent wake of the reactor building in calculating potential exposures. The x = distance from point of release to the receptor;

volumetric building wake correction factor, as defined in other variables are as given in h(2).

section 3-3.5.2 of Meteorology and Atomic Energy

1968, should be used only in the 0-8 hour period; it is (4) The atmospheric diffusion model for used with a shape factar of 1/2 and the minimum ground level releases is based on the information in the croms-sectional area ot the reactor building only. table below.

(2) The basic equation for atmospheric diffuision from a ground level point source is: Ti me Following Accident Atmospheric Conditions x/0 =

41Uy oz 0.8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> Pasquill Type F, windspeed I meter/see, uniform direction Where

8-24 hours Pasquill Type F, windspeed 1 meter/see, the short term average centerline value of the variable direction within a 22.50 sector ground level concentration (curie/rmeter 3 )

Q amount of material released (curie/see) 1-4 days (a) 40% Pasquill Type D. windspeed 3 u windspeed (meter/sec) meter/see Oy =the horizontal standard deviation of the (b) 60% Pasquill Type F, windspeed 2 plume (nieters) [See Figure V-I. Page 48, meter/sec Nuclear Safrity. June 1961, Volume 2. (c) wind direction variable within a 22.50

sector Number 4. "Use of Routine Meteorological Observations for Estimating Atmospheric

4-30 days (a) 33.3% Pasquill Type C, windspeed 3 Dispersion," F. A. Gifford. Jr.]

ID =the vertical standard deviation of the plume meter/sec (b) 33.3% Pasquill Type D, windspeed 3 (meters) ISee Figure V-2, Page 48.Nuclear meter/sec Safety, June 1961, Volume 2, Number 4. (c) 33.3% Pasquill Type F, windspeed 2

"Use of Routine Meteorological meter/sec Observations for Estimating Atmospheric (d) Wiind direction 33.3% frequency in a Dispersion," F. A. Gifford, Jr.] 22.5' sector

(3) For time periods of greater than 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> (5) Figures 3A and 3B give the ground level the plume should be assumed to meander and spread release atmospheric diffusion factors based on the uniformly over a 22.5" sector. The resultant equation is: parameters given in h(4),

I I A

10-3 S

ELEVATED RELEASE

ATMOSPHfERIC DIFFSON FACTORS

S,0-8 HLJUR RiEtASE TIME

• . FIGURE 1VA)

10-4

7. .. ... . . . . ... h*-Vb....

_ . . .... . . . L.. . .÷ .

'*'--Ar S10-5 _

S- .d_........___.....I

-1 - -*.

10-4

102 103 10410

Distance from Release Point (meters)

1.3-5

i

-o : -T -r----.- . .. -

.... II

................ ......... ' --

10-3

10-

io2 iO3 o o Distance from Release Point (meters)

z -6

. % -'N

p

.. 1

.- LEXMATF&ULEASt. .

ATMC kSH9R1C--D##ISMQ FACTORS

1-4.C)A'Y.R:1LASE Tljfg.~

FIGURE M()

• 10-

-- t................. .

... .. . . .Ii

.i..

• 1 I '

10-5 * [ ....

- 4-2 E

I I" /' --- S --------

0

sk TfI1It40#1

010

---

IL-

zzjzz~~I~

. . I ý

t VL~~I XA¶N.AIX

i I

SI.

-I I

Jpi i:. i:F [I xI '%

71 ..1 1f

10

-NI

0l 10-8

102 103 Distance from Release Point (meters)

1.3-7

EUiVA"~bRIES

ATAMSW ON f-OR

• .. 4

• S

TtM

..........

• .,. . .~

4-1

10 -5i IL -L.4 -4 T V: _ _7j J.

I x___

I Iv. I4N.N

INi

--

- ------

I

7:'.

I~w z..L.J

10-

102 10

3

.1o4 Distance from Release Point (meters)

1.3-8

r

, EtVAMD. RELEASE

ATMOSPHERIC DISPERSION FACTORS

FOR .FUMIGATION qONDITIONS

-ATMOSPHER ICCdiNDITIONgS.

PASOUILL TYPE F

WINDSPEED I METER/SEC

10-2 " F1GUHE It ......

i

.. .....

h60

C,, ... ..... .. .............

,.. ..... .*. .. ..-.

.....................................

i i: T

j 7  : i

0

.

w I  : a

10- ~ H

-F-9 WT

N

5

10-

I,.A

7-n LTL

4-. 4--4

10-6

102 103 104 105 Distance from Release Point (meters)

3..9)

w ~

K" i

3

2.5 h---- FIGU^R'E 2 1  :

T. I-

0

._. . ... ..

0 .M. :Ii u

-77 I

0

• I

-I..

• I I

ra * I

cc

5i t St.

ii 3; 1 I

-i

6i iTd

0.5

0 .1.~3

102 102 104 Dlsnme from Structur (won W~

0.-

IA

U V .-- . _.-.- . .

I~ A

VARIOUS TIN ESF LC14HN CI T

FIGURE V(A)

L-1

8-24 hours .~

10-5 L

102 10a3 10 10

Distance from Structure Imeters)

- lA0TMOSERL~qIF LLStOq Fibt

~~ .~ .~... .. .. . .VARIOUS TIMES FOULOWING IAC IrINT

~ . ~-.. FIGURE 30 3B)

0-8 hours

....................

.. 43.............................

ta . ~~.

.....

.

I JI

I. ... . . .. .. .

I. i

4 -t

103 10LL

Dit6Ic fromzz Stutr (meters