Regulatory Guide 1.3: Difference between revisions

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{{Adams
{{Adams
| number = ML003739601
| number = ML13350A383
| issue date = 06/30/1974
| issue date = 06/30/1973
| title = Assumptions Used for Evaluating the Potential Radiological Consequences of a Loss of Coolant Accident for Boiling Water Reactors
| title = Assumptions Used for Evaluation the Potential Radiological Consequences of a Loss Coolant Accident for Boiling Water Reactor
| author name =  
| author name =  
| author affiliation = NRC/RES
| author affiliation = US Atomic Energy Commission (AEC)
| addressee name =  
| addressee name =  
| addressee affiliation =  
| addressee affiliation =  
Line 10: Line 10:
| license number =  
| license number =  
| contact person =  
| contact person =  
| document report number = RG-1.3, Rev 2
| case reference number = RG-1.003, Rev 1
| document type = Regulatory Guide
| document type = Regulatory Guide
| page count = 12
| page count = 12
}}
}}
{{#Wiki_filter:U.S. ATOMIC ENERGY COMMISSION  
{{#Wiki_filter:.!a Revision 1 P U.S. ATOMIC ENERGY COMMISSION
REGULATORY  
REGULATORY
DIRECTORATE  
DIRECTORATE  
OF REGULATORY  
OF REGULATORY  
STANDARDS Revision 2 June 1974 GUIDE REGULATORY  
STANDARDS Revision I June 1973 GUIDE REGULATORY  
GUIDE 1.3 ASSUMPTIONS  
GUIDE 1.3 ASSUMPTIONS  
USED FOR EVALUATING  
USED FOR EVALUATING  
THE POTENTIAL  
THE POTENTIAL  
RADIOLOGICAL  
RADIOLOGICAL  
CONSEQUENCES  
CONSEQUENCES
OF A LOSS OF COOLANT ACCIDENT FOR BOILING WATER REACTORS  
OF A LOSS OF COOLANT ACCIDENT FOR BOILING WATER REACTORS'


==A. INTRODUCTION==
==A. INTRODUCTION==
Section 50.34 of 10 CFR Part 50 requires that each applicant for a construction permit or operating license provide an analysis and evaluation of the design and performance of structures, systems, and components of the facility with the objective of assessing the risk to public health and safety resulting from operation of the facility.
S.'i'Cllil
50..;,I fI I('FR PlaII 50( eiliuir ls th:t each:1pl'icailll l a ,oittl t lrlic n pli ltm l ilil or olperaling 'ro',idtc an :!lhlvsis mtid evahaltion ol" the design and pl' ci; Iiiice of1 sitlicitlres. anld Components of ihtc I:,,iility with the otive t" assessing the risk to lputllic h10:1t ll :aitd -:lfelv resl frm Im , oporation ol'the laTilily. "h" de:;ipi basis loss (of' coolant accident l()C' A i5 )IliC ,I I p[st lat3ted accidents used 1o evaluate fil ade(l'iacv ofi these Sliltctures. s. and c..'tIIIpolt0elli s will lrespecl It tile public health safely.This Inidle -,i\'es :,ccepltble assumlptions lhat mavy be iseal ill eva\tial l- tihe radiological ctnsequcuces of' this accident for a boiling wlei leactor. Ill soniLC CLasCs, ntiitsnltal site chlaractelrisltics.


The design basis loss of coolant accident (LOCA) is one of the postulated accidents used to evaluate the adequacy of these structures, systems, and components with respect to the public health and safety.  This guide gives acceptable assumptions that may be used in evaluating the radiological consequences of this accident for a boiling water reactor. In some cases, unusual site characteristics, plant design features, or other factors may require different assumptions which will be considered on an individual case basis. The Advisory Committee on Reactor Safeguards has been consulted concerning this guide and has concurred in the regulatory position.
plant dest;i featlres.
 
or othlr li' l tolls nav:y retqglire dilferetit asstinlotionls w\hich wiill ble Ctiside Led on anl illtividulial case basis. The Advisoty ('Cimmnitee Oil Reactor S:ile'quards hias been.consul ted con:ernini lt is guide altnd has conceturred in tlie regulatorvy pl ýili inl.


==B. DISCUSSION==
==B. DISCUSSION==
After reviewing a number of applications for construction permits and operating licenses for boiling water power reactors, the AEC Regulatory staff has developed a number of appropriately conservative assumptions, based on engineering judgment and on applicable experimental results from safety research programs conducted by the AEC and the nuclear industry, that are used to evaluate calculations of the diological consequences of various postulated accidents.
Arler reviewtitt a titinumber or" applicationls for conslitiet iin ,t nuits mnd opetating licenses for boiling water reacolos.
 
tile AEIC Regulaltury staff has developed a rilniber ofl' appropriately conservalive al, ptinons. bliscd on en&inecring juidpneni and on applicable eXperimnenltal results fromn sa 'ty research progratus cndudcted by the AEC and(l tie nuclear industryv.
 
that are used ti) evaluale calculalions of tlie radiological consequetces of1 various postulated accidelel s.This guide lists acceptable assumptions that may he u-sed to evalutate the design basis LOCA of' a Boilinlg Wa enr Rcactor (IIWPR). It should be shown tlhal tlhetc.,lose cotnsequences will be within the guidelines of I(I CFR Part 100.C. REGULATORY
POSITION I. aIlle ,ssutllptiotis elatied I ll lte tcle:se o' l;ldia:lct ii iilellit l front1 th11 f0 I andl collt iilnltiill alle ;as I",lfows: a. "\'i- t l >y-f'ive percent, of tile equilih)iilutn radioactive iodine invetn tory fromt mia\ iliintt!'uitl pow'er opeiatioi of thie core slhuhld IV JssI.niCId
1)he imtncdililely available I'Mti leakaue fioin the primar:iyv reactor conttaiinment.


This guide lists acceptable assumptions that may be used to evaluate the design basis LOCA of a Boiling Water Reactor (BWR). It should be shown that the offsite dose consequences will be within the guidelines of 10 CFR Part 100. (During the construction permit review, guideline, exposures of 20 rem whole body and 150 rem thyroid should be used rather than the values given in § 100.11 in order to allow for (a) uncertainties in final design details and meteorology or (b) new data and calculational techniques that might influence the final design of engineered safety features or the dose reduction factors allowed for these features.)
Nine tV-mit percent ito this 2 perceill is to Ile assulmled ito he ill tile 'orto of'ei nlenial iodine. 5 percent of' this 25 percent ill ilic ltOnn oI particulate ioidine. and -I p't.eent of this 25 percinti it!lhe l'orit of' orwanic iodides.h. One hluldred percent o1' the eqLlihibritinlt radioaclive nhble gas itnVentorny developed Ir'omll IltaxitiltilM
C. REGULATORY
frill powver of' [lie %:oie should ble assumed it) lb ie tltedialtelv available lot hcakane It'oit tle leactol Coll lailllltent.
POSITION 1. The assumptions related to the release of radioactive material from the fuel and containment are as follows: a. Twenty-five percent of the equilibrium radioactive iodine inventory developed from maximum full power operation of the core should be assumed to be immediately available for leakage from the primary reactor containment.


Ninety-one percent of this 25 percent is to be assumed to be in the form of elemental iodine, 5 percent of this 25 percent in the form of particulate iodine, and 4 percent of this 25 percent in the form of organic iodides.
c. The .os tf' radiolo-ical deca, during holdup inl thle conwaiintient or othet bujildimes should ble taketn into accounltI.


b. One hundred percent of the equilibrium radioactive noble gas inventory developed from maximum full power operation of the core should be assumed to be immediately available for leakage from the reactor containment.
d. 'File reductiotn ill (hle alotii titt ' adioactive mtat.'rial
:ivailfable for leaka! ito the ehnvironineut bv Cloln[;,ilmllelln Spray'. recirtuilaing filter ni olhier eneih:eered sai'eity ftatlres mtay be takelil itlno :icclittl, bill the atounit of' reduction ihi concrentiation of radioactive materiils shotuld be evtlualed on :an ildividual case ba:sis.e. Tile primary conllaitnitent should ble assumed to leak at the leak rate incorporated or tio hie incolporated in thie technical specifications f'or the duration ill' [lie accident.2  The shotild be assuiited ito pass t"'l'iS guiidte is a revision Sate \l Giuide 3.2'lic on containni ent leakaee Iindcr atccid.nl conditio ot" I'e:ttlires protvidted to red ilce t' t':lkatpie of" radioalclive rtatlritits I'roll ItI" t'(l tnlit1inn n Will 11C he' eV3 litt 1 Lilt:nil individual case USAEC REGULATORY
GUIDES Copies of published guides may he obtained by reqcuest indicating the. divisions deilred to the US. Atomic Energy Commisvon.


c. The effects of radiological decay during holdup in the containment or other buildings should be taken into account.
Washington, D.C. 201545.Rcgulatnry Guides are issued in describe and make available to the public Attention;
Director of Regulatory Stalndards.


d. The reduction in the amount of radioactive material available for leakage to the environment by containment sprays, recirculating filter systems, or other engineered safety features may be taken into account, but the amount of reduction in concentration of radioactive materials should be evaluated on an individual case basis.  e. The primary containment should be assumed to leak at the leak rate incorporated or to be incorporated in the technical specifications for the duration of the USAEC REGULATORY
Comments and suggestion%
GUIDES Copies of published s nay be obtained by request Indicating the divisions desired to the US. Atomic Energy Commission, Washington, D.C. 20645, Regulatory Guides are issued to descobe and mal available to the Public Attention:
lot methods accptablte to the AEC Regulatory staff of implementing specilit part- of itiproverienti In theta guidemý ace ancouragd and should be sent to the Secretary the regulations.
Director of Regulatory Standrds.


Comments and suggestions for methods acceptable to the AEC Regulatory staff of implementing specific parts of Improvements In thes guides we encouraged and should be sent to the Secretary ths Commission's regulations, to delineate techniques used by the staff in of the Commission, US. Atomic Energy Commission, Washington, D.C. 20645, eveluating specific problems or postulatedi accidents, or to provide guidance to Attention:
tO delineale techniques used by the staff in of the Commitsion, US. Atomic Energy Commission.
Chief, Public Proceedings Staff.  applicants.


Regulatory Guides are not substitutes for regulations end compliance with them is not required.
Washington, D.C. 20545.ealuating specific problems or postulated accidents, or to provide guidence to Attention:
Chief, Public Proo-redinga Staff.applkOjlnts.


Methods end solutions different from thorn set out in The auides are issued in the following ten broad divisions:
Reoualo.yi Guides are not substitutes for regulations and compliance with them is not requited.
the guldes will be acceptable If they provide a basis for the findings requisite to the issuance or continuance of a permit or license by the Commission.


1. Power Reactors 6. Products 2. Research and Test Reactors
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.


===7. Transportation ===
1. Power Reactors 6. Products 2. Research and Test Reactors 7. 'Transrptortation
3. Fuels and Materials Facilities  
3. Fuels and Materials Facilities B. Occullationl Heialth PuhllshM quiewi will hbe revi-id periodically, as aip!iogilate.
8. Occupational Health Published guide will be revised periodically, as appropriate, to accommodate
4. Environmental and Siting 9. Antitrust Review comments to reflect new information or experience.


5. Materials and Plant Protection
to accommodate
10. General accident.
4. Environmental ard Siting 9. Antitrust Review cornrmenit
4nd in reflect new informatint, or experience.


1 The leakage should be assumed to pass directly to the emergency exhaust system without mixing_2 in the surrounding reactor building atmosphere and should then be assumed to be released as an elevated plume for those facilities with stacks. ' f. No credit should be given for retention of iodine in the suppression pool. 2. Acceptable assumptions for atmospheric diffusion and dose conversion are: a. Elevated releases should be considered to be at a height equal to no more than the actual stack height. Certain site dependent conditions may exist, such as surrounding elevated topography or nearby structures which will have the effect of reducing the actual stack height. The degree of stack height reduction should be evaluated on an individual case basis. Also, special meteorological and geographical conditions may exist which can contribute to greater ground level concentrations in the immediate neighborhood of a stack. For example, fumigation should always be assumed to occur; however, the length of time that a fumigation condition exists is strongly dependent on geographical and seasonal factors and should be evaluated on a case-by-case basis.4 (See Figures IA through 1D for atmospheric diffusion factors for an elevated release with fumigation.)  
S. Materials and Plant Protection tO, General
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 of iodine in transit.
----I *directly to the emergency exhaust system without mixing' in the. surrounding reactor building atmosphere and should then be assumed to be released as an elevated plume for those facilities with stacks.4 f. No credit should be given for retention of iodine in the suppression pool.2. Acceptable assumptions for atmospheric diffusion and dose conversion are: a. Elevated releases should be considered to be at a height equal to no more than the actual stack height.Certain site dependent conditions may exist, such as surrounding elevated topography or nearby stnictures which will have the effect of reducing the actual stack height. The degree of stack height reduction should be evaluated on an individual case hasis. Also. special meleorologicaI
and geographical conditions may exist which can contribute to greater ground level concentrations in the immediate neighborhood of a stack. For example. fumigation should always be assumed to occur: however. tlh- length of time that a rumigation condition exists is strongly dependent on geographical and seasonal factors and should be evaluated on a case-by-case basis." (See Figures I A through ID for atmospheric diffusion factors for an 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 of iodine in transit.c. For the first 8 hours, the breathing rate of persons offsite should be assumed to be 3.47x 10'cubic meters per second. From 8 to 24 hours 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 end of the accident, the rate should be assumed to be 2.32 x 10-4 cubic meters per second. (These values were developed from the average daily breathing rate 12 x 107 cm 3/dayl assumed in the report of ICRP, Committee 11-1959.)3 1n some c-ases, credit fur mixing will he allowed: however.the amount of credit allowed will be evaluated on an individual case basis."Credit for an elevated release should be given only if the pitnt of release is (I) nire than two and one-half times the height of any structure close enough to afrect the dispersion of the plume, or (2) located far enough from any structure which could have an efrect on the dispersion of the plume. For those It\R's without stacks the atmospheric diffusion factors assuming pround level release given in section 2.h. should be used to determine site acceptability.


c. For the first 8 hours, the breathing rate of persons offsite should be assumed to be 3.47x 104 cubic meters per second. From 8 to 24 hours following the accident, the breathing rate should be assumed to be 1.75 x 10"4 cubic meters per second. After that until the end of the accident, the rate should be assumed to be 2.32 x 10-4 cubic meters per second. (These values were 1The effect on containment leakage under accident conditions of 1 features provided to reduce the leakage of radioactive materials from the containment will be evaluated on an individual case basis. "2 In some cases, credit for mixing will be allowed; however, the amount of credit allowed will be evaluated on an individual case basis. ' Credit for an elevated release should be given only if the point of release is (1) more than two and one-half times the height of any structure close enough to affect the dispersion of the plume, or (2) located far enough from any structure which could have an effect on the dispersion of the plume. For those BWR's without stacks the atmospheric diffusion factors assuming ground level release given in section 2.h. should be used to determine site acceptability.
For sites located more than 2 miles from large bodies of water such as oceans or one of (the Great takes. a fumigation condition should be assumed to exist at the time of the accident and continue for one-half hour. For sites located less than 2 miles from large bodies of water, a fumigation condition should be assumed to exist at the time of the accident and continue for 4 hours.d. The iodine dose conversion factors are given in ICRP Publication
2, Report of Comtmittee i1."Permissible Dose for Internal Radiation." 1959.e. External whole body doses should be calculated using Infinite Cloud" assumptions.


4 For sites located more than 2 miles from large bodies of water such as oceans or one of the Great Lakes, a fumigation condition should be assumed to exist at the time of the accident and continue for one-half hour. For sites located less than 2 miles from large bodies of water, a fumigation condition should be assumed to exist at the time of the accident and continue for 4 hours.developed from the average daily breathing rate [2 x 107 cm 3/day] assumed in the report of ICRP, Committee
i.e.. the dimensions of the cloud are assumed to be large compared to ihe distance Ihat Ihic gamma rays and beta particles travel."Such a cloud would be considered atn infinite cloud for a receptor at the center because any additional (gamma andi beta emitting material beyond t(le clotud dimensions would not alter the flux of Igatmna rays andl beta particles to the receptor" (Meteorology and Atomic Energy, Section 7.4.1.1-editorial additions made so that gamnma and beta emitting material could be considered).  
11-1959.). 
Under ihese conditions the rate of energy.absorption per unit volume is equal to the rate ortenergy released per unit volume. For an infinite uniform cloud containing X curies of beta radioactivity per cubic meter the beta dose in air at the cloud center is: D. = 0.457 E The surface body dose rate from beta emitters in the infinite cloud can be approximated as being one-half this amount (i.e.. 01D- = 0.23 EOX).For gamma emitting material the dose rate in air at the cloud center is: DA= 0.507 E rX From a semi-infinite cloud. the gamma dose rate in air is: S=o.2s Ex Where D= beta dose rate from an infinite cloud (rad/sec)DE= gamma dose rate from an infimite cloud (rad/sec)EO = average beta energy per disintegration (Mev/dis)Ei = average gamma energy per disintegration (Mevldis)X = concentration of beta or gatnma emitting isotope in the cloud (curie/mr 3)f. The following specific assumptions are acceptable with respect to the radioactive cloud dose calculations: (I) The dose at any distance from the reactor should be calculated based on the maximunm concentration in the plume at that distance taking into account specific meteorological, topographical, and other characteristics which may affect the maximium plume concentration.
d. The iodine dose conversion factors are given in ICRP Publication
2, Report of Committee II, "Permissible Dose for Internal Radiation," 1959. e. External whole body doses should be calculated using "Infinite Cloud" assumptions, i.e., the dimensions of the cloud are assumed to be large compared to the distance that the gamma rays and beta particles travel. "Such a cloud would be considered an infinite cloud for a receptor at the center because any additional  
[gamma and] beta emitting material beyond the cloud dimensions would not alter the flux of [gamma rays and] beta particles to the receptor" (Meteorology and Atomic Energy, Section 7.4.1.1-editorial additions made so that gamma and beta emitting material could be considered).  
Under these conditions the rate of energy absorption per unit volume is equal to the rate of energy released per unit volume. For an infinite uniform cloud containing X curies of beta radioactivity per cubic meter the beta dose in air at the cloud center is: SD4g = 0.457 EX The surface body dose rate from beta emitters in the infinite cloud can be approximated as being one-half this amount (i.e., 0D+/- = 0.23 ETX). For gamma emitting material the dose rate in air at the cloud center is: D 0.507 .EX From a semi-infinite cloud, the gamma dose rate in air is: S= 0.25 E~x Where = beta dose rate from an infinite cloud (rad/sec)  
gamma dose rate from an infinite cloud (rad/sec)  
Eg = average beta energy per disintegration (Mev/dis)  
EB = average gamma energy per disintegration  
"(Mev/dis)  
X = concentration of beta or gamma emitting isotope in the cloud (curie/m 3) f. The following specific assumptions are acceptable with respect to the radioactive cloud dose calculations:  
(1) The dose at any distance fronthe reactor should be calculated based on the maximum concentration in the plume at that distance taking into account specific meteorological, topographical, and other characteristics which may affect the maximum plume concentration.


These site related characteristics
These site related characteristics
1.3-2 must be evaluated on an individual case basis. In the case of beta radiation, the receptor is assumed to be exposed to an infinite cloud at the maximum ground level concentration at that distance from the reactor. In the case of gamma radiation, the receptor is assumed to be exposed to only one-half the cloud owing to the presence of the ground. The maximum cloud concentration always should be assumed to be at ground level. (2) The appropriate average beta and gamma energies emitted per disintegration, as given in the Table of Isotopes, Sixth Edition, by C. M. Lederer, J. M. Hollander, I. Perlman; University of California, Berkeley;
1.3-2 must be evaluated on an individual case basis. In the case of beta radiation, the receptor is assumed to be exposed to an infinite cloud at the maxinmum ground level concentration at that distance from the reactor. In the case of gamma radiation, the receptor is assumed to be exposed to only one-half the ckud owing to tcie presence of' the ground. Tile maxinmm cloud concentration always should be assumed to be at ground level.(2) The appropriate average beta and gamnia energies emitted per disintegration, as given in the Table of Isotopes.
Lawrence Radiation Laboratory;
 
should be used. g. For BWR's with stacks the atmospheric diffusion model should be as follows: (1) The basic equation for atmospheric diffusion from an elevated release is: exp(-h 2 I2oz 2) X/Q iu a Sy~z Where X = the short term average centerline value of the ground level concentration (curie/meter
Sixth Edition, by C. M. Lederer. J. M.Hollander, I. Perhlan; University ofCalifornia.
3) Q = amount of material released (curie/sec)  
 
u = windspeed (meter/sec)  
Berkeley: Lawrence Radiation Laboratory:
y= the horizontal standard deviation of the plume (meters) [See Figure V-l, Page 48, Nuclear Safety, June 1961, Volume 2, Number 4, "Use of Routine Meteorological Observations for Estimating Atmospheric Dispersion," F. A. Gifford, Jr.] oz= the vertical standard deviation of the plume (meters) [See Figure V-2, Page 48, Nuclear Safety, June 1961, Volume 2, Number 4, "Use of Routine Meteorological Observations for Estimating Atmospheric Dispersion," F. A. Gifford, Jr.] h = effective height of release (meters) (2) For time periods of greater than 8 hours the plume from an elevated release should be assumed to meander and spread uniformly over a 22.50 sector. The resultant equation is: 2.032 exp(-h 2/2az 2) x/Q a=ux Where x = distance from the release point (meters);  
should be used.g. For BWR's with stacks the atmospheric diffusion model should be as follows: (I) The basic equation for atmospheric diffusion from an elevated release is: exp(-h 2/2Oz 2)VQ Tu y 0z Where x = the short term average centerline value of the ground level concentration (curie/meter
other variables are as given in g(l).(3) The atmospheric diffusion model s for an elevated release as a function of the distance from the reactor, is based on the information in the table below.Time Following Accident Atmospheric Conditions
3)Q = amount of material released (curie/see)
0-8 hours See Figure I(A) Envelope of Pasquill diffusion categories based on Figure A7 Meteorology and Atomic Energy-1968, assuming various stack heights; windspeed  
u = windspeed (meter/sec)
1 meter/sec;  
Gy = the horizontal standard deviation of the plume (meters) [See Figure V-i. Page 48.Nuclear Safety, June 1961, Volume 2.Number 4, "Use of Routine Meteorological Observations for Estimating Atmospheric Dispersion," F. A. Gifford, Jr.)z= the vertical standard deviation of the plume (meters) [See Figure V-2. Page 48, Nuclear Safety, June 1961, Volume 2, Number 4,"Use of Routine Meteorological Observations for Estimating Atmospheric Dispersion," F. A. Gifford, Jr.)h = effective height of release (meters)(2) For time periods of greater than 8 hours the plume from an elevated release should be assumed to meander and spread uniformly over a 22.50 sector. The resultant equation is: 2.032 exp(-h 2/2oz 2)x/Q =Where x = distance from the release point (meters);other variables are as given in g(1).(3) The atmospheric diffuision model' for an elevated release as a function of the distance from the reactor, is based on the information in the table below.Time Following Accident Atmospheric Conditions
uniform direction.
0-8 hours See Figure 1(A) Envelope o1" Pastluill diffusion categories based oil Figure A7 NI 'teorolog'
and Atomic I-netryo I tt(,1 , assuming various stack heights: vindspeed I me ier/see; uniform direction.
 
8-24 hours See Figure ItB) lEnvelope of Pasquill diffusion categories:
windspeed I meter/see:
variable direction within a 22.5 sector.1-4 days See Figure I[C) Envulope of Pasquill diffusion categories with the following relationship used to represent maximnnumn plume concentrations as a tumeltion of'distance: Atmospheric Condition Case I 40Y Pasquill A 601'} Pasquill C Atmospheric Condition Case 2 50% Pasquill CPasqtill D Atmospheric Condition Case 3 33.3',` Pasquill C 33.3% Pasquill D 33.3% Pasquill E Atmospheric Condition Case 4 33.3!, Pasquill 1)33.3, Pasquill E 33.3K- Pasquill F Atmospheric Condition Case 5 50r', Pasquill D 501? Pasquill F wind speed variable (Pasquill Types A. B. E.and F windspeed
2 memer/sec:
Pasquill Types C nid D windspeed
3 meter/sec)
variable direction within a 22.5" sector.4-30 days See Figure I(D) Same diffusion relations as given above- windspeed variable dependent on Pasquill Type used; wind direction
33.3" frequency in a 22.50 sector.11This model should be used until adequate site meteorological data are obtained.


8-24 hours See Figure I(B) Envelope of Pasquill diffusion categories;
In smote cases. avaitable information, such as meteorology, topography and geographical location.
windspeed
1 meter/sec;
variable direction within a 22.50 sector.  14 days See Figure 1(C) Envelope of Pasquill diffusion categories with the following relationship used to represent maximum plume concentrations as a function of distance:
Atmospheric Condition Case 1 40% Pasquill A 60% Pasquill C Atmospheric Condition Case 2 50% Pasquill C 50% Pasquill D Atmospheric Condition Case 3 33.3% Pasquill C 33.3% Pasquill D 33.3% Pasquill E Atmospheric Condition Case 4 33.3% Pasquill D 33.3% Pasquill E 33.3% Pasquill F Atmospheric Condition Case 5 50% Pasquill D 50% Pasquill F wind speed variable (Pasquill Types A, B, E, and F windspeed
2 meter/sec;
Pasquill Types C and D windspeed
3 meter/sec);
variable direction within a 22.50 sector.  4-30 days See Figure I(D) Same diffusion relations as given above; windspeed variable dependent on Pasquill Type used; wind direction
33.3% frequency in a 22.50 sector.  This model should be used until adequate site meteorological data are obtained.


In some cases, available information, such as meteorology, topography and geographical location, may dictate the use of a more restrictive model to insure a conservative estimate of potential offsite exposures.
may dictate the use of a more restrictive model to insure a conservative estimate of potential offtsite exposures.


1.3-3 h. For BWR's without stacks the atmospheric diffusion model 6 should be as follows: (1) The 0-8 hour ground level release concentrations may be reduced by a factor ranging from one to a maximum of three (see Figure 2) for additional dispersion produced by the turbulent wake of the reactor building in calculating potential exposures.
1.3-3 I h. For BIWR's without stacks dhe almospheric diffusion inodel6,should be as follows: (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 dispersion produced by the turbulent wake of the reactor building in calculating potential exposures.


The volumetric building wake correction factor, as defined in section 3-3.5.2 of Meteorology and Atomic Energy 1968, should be used only in the 0-8 hour period; it is used with a shape factor of 1/2 and the minimum cross-sectional area of the reactor building only. (2) The basic equation for atmospheric diffusion from a ground level point source is: 1 x/Q = 7rUOryc"Z Where (4) The atmospheric diffusion model for ground level releases is based on the information in the table below.Time Following Accident Atmospheric Conditions
The volumetric building wake correction factor, as defined in section 3-3.5.2 of Meteorology and Atomic Energy 1968, should be used only in the 0-8 hour period; it is used with a shape factar of 1/2 and the minimum croms-sectional area ot the reactor building only.(2) The basic equation for atmospheric diffuision from a ground level point source is:x/0 =41U y oz Where the short term average centerline value of the ground level concentration (curie/rmeter
0-8 hours Pasquill Type F, windspeed
3)Q amount of material released (curie/see)
1 meter/sec, uniform direction
u windspeed (meter/sec)
8-24 hours Pasquill Type F, windspeed
O y =the horizontal standard deviation of the plume (nieters)  
1 meter/sec, variable direction within a 22.50 sector 14 days (a) 40% Pasquill Type D, windspeed
[See Figure V-I. Page 48, Nuclear Safrity. June 1961, Volume 2.Number 4. "Use of Routine Meteorological Observations for Estimating Atmospheric Dispersion," F. A. Gifford. Jr.]ID =the vertical standard deviation of the plume (meters) ISee Figure V-2, Page 48.Nuclear Safety, June 1961, Volume 2, Number 4."Use of Routine Meteorological Observations for Estimating Atmospheric Dispersion," F. A. Gifford, Jr.](3) For time periods of greater than 8 hours the plume should be assumed to meander and spread uniformly over a 22.5" sector. The resultant equation is: 2.032 X/Q =azUX*Whe re x = distance from point of release to the receptor;other variables are as given in h(2).(4) The atmospheric diffusion model for ground level releases is based on the information in the table below.Ti me Following Accident Atmospheric Conditions
3 meter/sec (b) 60% Pasquill Type F, meter/sec (c) wind direction variable sector windspeed
0.8 hours Pasquill Type F, windspeed I meter/see, uniform direction 8-24 hours Pasquill Type F, windspeed
2 within a 22.50 x = the short term average centerline value of the ground level concentration (curie/meter
1 meter/see, variable direction within a 22.50 sector 1-4 days (a) 40% Pasquill Type D. windspeed
3) Q = amount of material released (curie/sec)  
3 meter/see (b) 60% Pasquill Type F, windspeed
u = windspeed (meter/sec)  
2 meter/sec (c) wind direction sector variable within a 22.50 4-30 days (a) 33.3% Pasquill Type C, windspeed  
ay = the horizontal standard deviation of the plume (meters) [See Figure V-1, Page 48, Nuclear Safety, June 1961, Volume 2, Number 4, "Use of Routine Meteorological Observations for Estimating Atmospheric Dispersion," F. A. Gifford, Jr.] z= the vertical standard deviation of the plume (meters) [See Figure V-2, Page 48, Nuclear Safety, June 1961, Volume 2, Number 4, "Use of Routine Meteorological Observations for Estimating Atmospheric Dispersion," F. A. Gifford, Jr.] (3) For time periods of greater than 8 hours the plume should be assumed to meander and spread unikormly over a 22.50 sector. The resultant equation is: 4-30 days (a) 33.3% Pasquill Type C, windspeed  
3 meter/sec (b) 33.3% Pasquill Type D, windspeed  
3 meter/sec (b) 33.3% Pasquill Type D, windspeed  
3 meter/sec (c) 33.3% Pasquill Type F, windspeed  
3 meter/sec (c) 33.3% Pasquill Type F, windspeed  
2 meter/sec (d) Wind direction  
2 meter/sec (d) Wiind direction  
33.3% frequency in a 22.50 sector (5) Figures 3A and 3B give the ground level release atmospheric diffusion factors based on the parameters given in h(4).   
33.3% frequency in a 22.5' sector (5) Figures 3A and 3B give the ground level release atmospheric diffusion factors based on the 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 S10-5 _......_ .....L ..÷ .7. -Vb.... .. ... .......10-4 S- .d_........___.....I
-1 --*.10 2 103 10410 Distance from Release Point (meters)1.3-5
:-o : -T -r----.- ... -.... ................
II .........
' --10-3 10-io 2  iO 3  o o Distance from Release Point (meters)z -6 i
.% -'N p..1 ATMC.-LEXMATF&ULEASt.


==D. IMPLEMENTATION==
.kSH9R1C--D##ISMQ
The purpose of the revision (indicated by a line in the margin) to this guide is to reflect current Regulatory staff practice in the review of construction permit appli cations, and the revised guide, therefore, is effective immediately.
FACTORS 1-4.C)A'Y.R:1LASE
Tljfg.~FIGURE M()--t.................
.*10-10-5 E 0 010 10... .. ..Ii i.. ..I '*1* [ ....-4-2 I I " /'---S --------sk TfI1It40#
1 t I------------
L- ..I ýi I SI.:zzjzz~~I~
VL~~I XA¶N.AIX-I I Jpi i:.i:F [ I xI '%71 ..1 1f-NI 0l 10-8 102 103 Distance from Release Point (meters)1.3-7
* .. 4 EUiVA"~bRIES
ATAMSW ON f-OR TtM..........
* S* .,. ..~4-1 1 0-5i 10-IL -L.4 -4 T V : J. _ _7j I x___I Iv. I4N.N INi-- -------7:'.I~w z..L.J I 102 10 3.1o4 Distance from Release Point (meters)1.3-8 r , EtVAMD. RELEASE ATMOSPHERIC
DISPERSION
FACTORS FOR .FUMIGATION
qONDITIONS-ATMOSPHER
IC CdiNDITIONgS.


2.032 X/Q =-Where x = distance from point of release to the receptor;
PASOUILL TYPE F WINDSPEED
other variables are as given in h(2).1.3-4
I METER/SEC" F1GUHE It ......10-2 i;h 60 ..... ..0 C,, 10-... ..... .. .............
10 10r 5 0 U 10 102 J-. 4 -4 .--j.1 If Att~ -i4i* ...i .--I 41 j f I -I-F I-j I 1Z.LJ- ---J-4----------4-f~-, 4~ +~-4 L 77--4Lw I III p 1 *t -14--p 5 meters4.4-1-,-- 4 -1- + --4 -1--i--1-1-k Li -.4-U----4--- 4- + --4-- +/- -1 -4--1--4---t-
i i: T j .7 : i.....................................  
-4.. 4-4- -+ -s-- + -- 4 CF'I(PaqII
,.. ..... .. ..-.I : a w~ H-F-9 WT N I,.A 7-n LTL 4-. 4--4 10-5 10-6 102 103 104 105 Distance from Release Point (meters)3..9)
Diffis~io' (T ssSow asryas.h -t-L ADS-j~~~-.~~~~~.-4-~~~~~~~~~-~
w ~K" i 3 2.5 h----0 0 u 0 ra cc 5i FIGU^R'E 2 1 : T .I-._ ... .. ...M. :Ii-77 I t* I-I..* I I* I 0.5 0 102 St.ii 3; 1* I-i.1. iTd~3 6i 102 104 Dlsnme from Structur (won W~0.-  
1 .I ~ 4-~-- -4-- ----4-4-4- 4 4--+--I-4 14-14----4--r 10-j i-v 1.4 t--4.- 4----I -J I--4--I II-4 10 Distance from Release Point (meters) 1.3-5-4-!ILI I--. -4 -I- 4-I .4 4 j +-4 I-I ~ ~ I K ELVTERLES-7-1;vh-75 meterst -7 10-12 10 5
I A U V .-- ._.-.- ..I~ A VARIOUS TIN ESF LC14HN CI T FIGURE V(A)L-1 8-24 hours .~10a 3  10 10 Distance from Structure Imeters)10-5 L 102
10 -S2Tm d~ 7
-lA0TMOSERL~qIF
* I .I 1 I .L ....... ....1 .ELEVATED RELEASE :ATMOSPHERIC
LLStOq Fibt~ .~ ~ .~... .. .. ..VARIOUS TIMES FOULOWING
DIFFUSION
IAC Ir INT~ .~-.. FIGURE 3B) 30 0-8 hours....................  
FACTORS S8-24 HOUR RELEASE TIME.~z1Iiii~d42b~c..
..43.............................
..1 -...LJL
~~. ......ta .I JI I. .... ......I. i 4 -t 103 10LL Dit6Ic fromzz Stutr (meters}}
................................................................
*1
* I.103 105 Distance from Release Point (meters) 1.3-6 LZiIzt10-LL C 0 -01-I 10-k 101'I E"I I¸ i. : I.J'-!j`:'j171T;,  
p.ýC C I-............. V4, T; 7 :j. 1;: L T:T. -v A:.wa- m...  ts: 7 'wr VT -J.  i f 11 Ta; -H T 4 ým w; 7W ýIzr, lit: tlý T: 777 v1! L ýi Ri; 'Tit ;7: v T T: 4.,:.  47: + 10 3; q E. :F Em T= ------ UM --- --- H7 Tý rr I iýt i4i,-7777-77 i, T+I :7: L '-77 77 -w tý I" tit lp 14, TM L-,.  4,n mg tj a M IL 7; -T (,w/ow) DIXjom=d uoisnula I LX t'i.iII f%.  6 I 0 a.  U 3 .5 E 0 T' c'9 a I-:1 Id :1 1 -L-L I.... I- -
10 10-U.1 fie 104I H ---4- ij~TTI YE T-I---* I-1 1: J: f I I I 7i*~ jf1i~li itIl~t 'i v.  4 77ý 7*'7.-.. 
9 itl: L .... ...  jaAff:.  Ir or .4.7 pp Lt, I t li Will N, -fý 'aull i!: ift H.: 44 lAA iififi` q M rju MA :; IT C I -.1. i. A- W:: C ali ItL T I I hiAl.; -7 -it W III %L' 1, AA 7-- -77 i X, I i I C 11 10 -114 a Z_ý_L ... -------a I _T 1T Ay- ug -1 -1:: IN lit ItMA HT jlllflllý
4i" V.  V1 Wi R! 19 INER i U !;I i 11'4ý M P4 Fý, 4ý4 17 Tf iflul il M Ml 1UN IMU- N"I -7r+ !it liil lv, fili I P11 flif :1 fl IfAma, lFfff M, I El U. 1W , Nt I f ýf AT I A it ::ij :q.1=i; Yi j ::;l it qi: T 7 7 102+/-t I--4,1++Distance from Release Point (meters) 1.3-8 I I ..w I ~ ~ EIE --__ _7 -;. 1-_4L ~ 1 t.1:1 103 104
1- -"!I I .1 II lit I. 10-2 10-3 0 10-5 -6 10 104 Distance from Release Point (meters) 1 .3-9: !{iELEVATED
RELEASE ATMOSPHERIC
DISPERSION
FACTORS FOR FUMIGATION
CONDITIONS
7ý " =: -ATMOSPHERIC
CONDITIONS
PASQUlLL TYPE F ....  fTWINDSPEED
1 METER/SEC
1=507 7etrs Sh=75 1 Smeters '"!I IL10 meesj h=125~J l=15 $1er 2 10 103 105
4.)___ ______N r rrfI Vt I 4----:17 i4 liP\  3 2.5 -1.5 *1-.. ..i7i-tx Si.Iil-. ----V r Id Il,+-..-.- T-;-t.:-.
-+ ..7T TW-4-BUILDING WAKE CORRECTION
FACTOR--i-i-i-,--I T LL 4 V Ilil I I14I.I* 1 I!1 U--ii jr I I  
-+/-..L-.----I-
Hhl'* Will I I I I
iIi 7 ..1-7 H'47_. S. .. .: :.; :;;;T I r 1'4r ii III 10"*(T.1 177f II Z II!I,-I--.... .meters 2 0.5A-1500
meers20 0.5A-2000
meters 0.5 0-F-, 103 Distance from Structure (meters)-I.-.4-Th.T t nl&#xfd;, ! z. .! ! ! ........I I .. .. .t .I , I I I I I I J i ., r ,llJh n I , .,,I I I t ' t ... .I I !;; ; ; ; ; ....i n.- I I I I I I I I ..... _I , , l i ,7 1 ] 1 , 1 I I I I I I~l , ~ , , II IIF:I]!i III if!i .l 2-_-i N!I <t" i_-&#xfd;7&#xfd;q 4_4-----,,--- -.....T -
1w4Thz4 GROUND LEVEL RELEASE ATMOSPHERIC
DIFFUSION
FACTORS FOR VARIOUS TIMES FOLLOWING
ACCIDENTw TTW T I i I '' ; I I T 44-3 3 _7. -<J4jT2: -8-24hours,:..
0V U. 7 yjIIti;; : Jfi.ti~ S4-34 days, t&#xfd;z5 L 1O2 163 Distance from structure (meters)1.3-11 10-2 10-10-I I I- -I 111r .I f&#xfd; I I n if"ITF-1 I I I I I " ' H I , I .. .. .. .. -.. .. -Il- 11 i &#xfd; Llt" &#xfd; r! " &#xfd; 4 PP f " rH 9 Ml + t E I + &#xfd; T &#xfd; I t -, -, I t-11 --I 10" 104 tj M-f i i-t)-8 hours fl- #
-.-4--GROUND
LEVEL RELEASE T ..,2 ~~~ ATMOSPHERIC
DIFFUSION
ATR O I' VARIOUS TIMES FOLLOWING
ACCIDENT ,T t {-0-8 hours
* r71 V .-t 74* -T4:+o r ~ 74i :R.P I I! ii I II  4- Tr+/-1--in 1-4 days T 1A -4--. 4 T-- q 1 +1.1 4 4~ y~-* '. 4~ IIN 44'7 ...........-i4+/-AET'1Th12-rV
jL4-4-I -"12% -t I I I I Ii A-- .7: 4.,-4 T'4 A L 1 -I I I I --= ----_______Distance from S tructure (meters) 1 1.3-12 414 4. -I-.Li--lU E .2 70~ 10 10 17F;I-.-I-.-4.--T 4-4 f T~ 1 4 &#xfd;I.  T---4-i J JJ LI I;; 41 rEtLI L 1'I -I--4 4+/- -4+/-U A 10.Al ff! --5 L--10-T-4-}}


{{RG-Nav}}
{{RG-Nav}}

Revision as of 19:51, 12 October 2018

Assumptions Used for Evaluation the Potential Radiological Consequences of a Loss Coolant Accident for Boiling Water Reactor
ML13350A383
Person / Time
Issue date: 06/30/1973
From:
US Atomic Energy Commission (AEC)
To:
References
RG-1.003, Rev 1
Download: ML13350A383 (12)
v • d • e


.!a Revision 1 P U.S. ATOMIC ENERGY COMMISSION

REGULATORY

DIRECTORATE

OF REGULATORY

STANDARDS Revision I June 1973 GUIDE REGULATORY

GUIDE 1.3 ASSUMPTIONS

USED FOR EVALUATING

THE POTENTIAL

RADIOLOGICAL

CONSEQUENCES

OF A LOSS OF COOLANT ACCIDENT FOR BOILING WATER REACTORS'

A. INTRODUCTION

S.'i'Cllil

50..;,I fI I('FR PlaII 50( eiliuir ls th:t each:1pl'icailll l a ,oittl t lrlic n pli ltm l ilil or olperaling 'ro',idtc an :!lhlvsis mtid evahaltion ol" the design and pl' ci; Iiiice of1 sitlicitlres. anld Components of ihtc I:,,iility with the otive t" assessing the risk to lputllic h10:1t ll :aitd -:lfelv resl frm Im , oporation ol'the laTilily. "h" de:;ipi basis loss (of' coolant accident l()C' A i5 )IliC ,I I p[st lat3ted accidents used 1o evaluate fil ade(l'iacv ofi these Sliltctures. s. and c..'tIIIpolt0elli s will lrespecl It tile public health safely.This Inidle -,i\'es :,ccepltble assumlptions lhat mavy be iseal ill eva\tial l- tihe radiological ctnsequcuces of' this accident for a boiling wlei leactor. Ill soniLC CLasCs, ntiitsnltal site chlaractelrisltics.

plant dest;i featlres.

or othlr li' l tolls nav:y retqglire dilferetit asstinlotionls w\hich wiill ble Ctiside Led on anl illtividulial case basis. The Advisoty ('Cimmnitee Oil Reactor S:ile'quards hias been.consul ted con:ernini lt is guide altnd has conceturred in tlie regulatorvy pl ýili inl.

B. DISCUSSION

Arler reviewtitt a titinumber or" applicationls for conslitiet iin ,t nuits mnd opetating licenses for boiling water reacolos.

tile AEIC Regulaltury staff has developed a rilniber ofl' appropriately conservalive al, ptinons. bliscd on en&inecring juidpneni and on applicable eXperimnenltal results fromn sa 'ty research progratus cndudcted by the AEC and(l tie nuclear industryv.

that are used ti) evaluale calculalions of tlie radiological consequetces of1 various postulated accidelel s.This guide lists acceptable assumptions that may he u-sed to evalutate the design basis LOCA of' a Boilinlg Wa enr Rcactor (IIWPR). It should be shown tlhal tlhetc.,lose cotnsequences will be within the guidelines of I(I CFR Part 100.C. REGULATORY

POSITION I. aIlle ,ssutllptiotis elatied I ll lte tcle:se o' l;ldia:lct ii iilellit l front1 th11 f0 I andl collt iilnltiill alle ;as I",lfows: a. "\'i- t l >y-f'ive percent, of tile equilih)iilutn radioactive iodine invetn tory fromt mia\ iliintt!'uitl pow'er opeiatioi of thie core slhuhld IV JssI.niCId

1)he imtncdililely available I'Mti leakaue fioin the primar:iyv reactor conttaiinment.

Nine tV-mit percent ito this 2 perceill is to Ile assulmled ito he ill tile 'orto of'ei nlenial iodine. 5 percent of' this 25 percent ill ilic ltOnn oI particulate ioidine. and -I p't.eent of this 25 percinti it!lhe l'orit of' orwanic iodides.h. One hluldred percent o1' the eqLlihibritinlt radioaclive nhble gas itnVentorny developed Ir'omll IltaxitiltilM

frill powver of' [lie %:oie should ble assumed it) lb ie tltedialtelv available lot hcakane It'oit tle leactol Coll lailllltent.

c. The .os tf' radiolo-ical deca, during holdup inl thle conwaiintient or othet bujildimes should ble taketn into accounltI.

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

ivailfable for leaka! ito the ehnvironineut bv Cloln[;,ilmllelln Spray'. recirtuilaing filter ni olhier eneih:eered sai'eity ftatlres mtay be takelil itlno :icclittl, bill the atounit of' reduction ihi concrentiation of radioactive materiils shotuld be evtlualed on :an ildividual case ba:sis.e. Tile primary conllaitnitent should ble assumed to leak at the leak rate incorporated or tio hie incolporated in thie technical specifications f'or the duration ill' [lie accident.2 The shotild be assuiited ito pass t"'l'iS guiidte is a revision Sate \l Giuide 3.2'lic on containni ent leakaee Iindcr atccid.nl conditio ot" I'e:ttlires protvidted to red ilce t' t':lkatpie of" radioalclive rtatlritits I'roll ItI" t'(l tnlit1inn n Will 11C he' eV3 litt 1 Lilt:nil individual case 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 ace ancouragd and should be sent to the Secretary the 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 mixing' in the. surrounding reactor building atmosphere and should then be assumed to be released as an elevated plume for those facilities with stacks.4 f. No credit should be given for retention of iodine in the suppression pool.2. Acceptable assumptions for atmospheric diffusion and dose conversion are: a. Elevated releases should be considered to be at a height equal to no more than the actual stack height.Certain site dependent conditions may exist, such as surrounding elevated topography or nearby stnictures which will have the effect of reducing the actual stack height. The degree of stack height reduction should be evaluated on an individual case hasis. Also. special meleorologicaI

and geographical conditions may exist which can contribute to greater ground level concentrations in the immediate neighborhood of a stack. For example. fumigation should always be assumed to occur: however. tlh- length of time that a rumigation condition exists is strongly dependent on geographical and seasonal factors and should be evaluated on a case-by-case basis." (See Figures I A through ID for atmospheric diffusion factors for an 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 of iodine in transit.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'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 end of the accident, the rate should be assumed to be 2.32 x 10-4 cubic meters per second. (These values were developed from the average daily breathing rate 12 x 107 cm 3/dayl assumed in the report of ICRP, Committee 11-1959.)3 1n some c-ases, credit fur mixing will he allowed: however.the amount of credit allowed will be evaluated on an individual case basis."Credit for an elevated release should be given only if the pitnt of release is (I) nire than two and one-half times the height of any structure close enough to afrect the dispersion of the plume, or (2) located far enough from any structure which could have an efrect on the dispersion of the plume. For those It\R's without stacks the atmospheric diffusion factors assuming pround level release given in section 2.h. should be used to determine site acceptability.

For sites located more than 2 miles from large bodies of water such as oceans or one of (the Great takes. a fumigation condition should be assumed to exist at the time of the accident and continue for one-half hour. For sites located less than 2 miles from large bodies of water, a fumigation condition should be assumed to exist at the time of the accident and continue for 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.d. The iodine dose conversion factors are given in ICRP Publication

2, Report of Comtmittee i1."Permissible Dose for Internal Radiation." 1959.e. External whole body doses should be calculated using Infinite Cloud" assumptions.

i.e.. the dimensions of the cloud are assumed to be large compared to ihe distance Ihat Ihic gamma rays and beta particles travel."Such a cloud would be considered atn infinite cloud for a receptor at the center because any additional (gamma andi beta emitting material beyond t(le clotud dimensions would not alter the flux of Igatmna rays andl beta particles to the receptor" (Meteorology and Atomic Energy, Section 7.4.1.1-editorial additions made so that gamnma and beta emitting material could be considered).

Under ihese conditions the rate of energy.absorption per unit volume is equal to the rate ortenergy released per unit volume. For an infinite uniform cloud containing X curies of beta radioactivity per cubic meter the beta dose in air at the cloud center is: D. = 0.457 E The surface body dose rate from beta emitters in the infinite cloud can be approximated as being one-half this amount (i.e.. 01D- = 0.23 EOX).For gamma emitting material the dose rate in air at the cloud center is: DA= 0.507 E rX From a semi-infinite cloud. the gamma dose rate in air is: S=o.2s Ex Where D= beta dose rate from an infinite cloud (rad/sec)DE= gamma dose rate from an infimite cloud (rad/sec)EO = average beta energy per disintegration (Mev/dis)Ei = average gamma energy per disintegration (Mevldis)X = concentration of beta or gatnma emitting isotope in the cloud (curie/mr 3)f. The following specific assumptions are acceptable with respect to the radioactive cloud dose calculations: (I) The dose at any distance from the reactor should be calculated based on the maximunm concentration in the plume at that distance taking into account specific meteorological, topographical, and other characteristics which may affect the maximium plume concentration.

These site related characteristics

1.3-2 must be evaluated on an individual case basis. In the case of beta radiation, the receptor is assumed to be exposed to an infinite cloud at the maxinmum ground level concentration at that distance from the reactor. In the case of gamma radiation, the receptor is assumed to be exposed to only one-half the ckud owing to tcie presence of' the ground. Tile maxinmm cloud concentration always should be assumed to be at ground level.(2) The appropriate average beta and gamnia energies emitted per disintegration, as given in the Table of Isotopes.

Sixth Edition, by C. M. Lederer. J. M.Hollander, I. Perhlan; University ofCalifornia.

Berkeley: Lawrence Radiation Laboratory:

should be used.g. For BWR's with stacks the atmospheric diffusion model should be as follows: (I) The basic equation for atmospheric diffusion from an elevated release is: exp(-h 2/2Oz 2)VQ Tu y 0z Where x = the short term average centerline value of the ground level concentration (curie/meter

3)Q = amount of material released (curie/see)

u = windspeed (meter/sec)

Gy = the horizontal standard deviation of the plume (meters) [See Figure V-i. Page 48.Nuclear Safety, June 1961, Volume 2.Number 4, "Use of Routine Meteorological Observations for Estimating Atmospheric Dispersion," F. A. Gifford, Jr.)z= the vertical standard deviation of the plume (meters) [See Figure V-2. Page 48, Nuclear Safety, June 1961, Volume 2, Number 4,"Use of Routine Meteorological Observations for Estimating Atmospheric Dispersion," F. A. Gifford, Jr.)h = effective height of release (meters)(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 /> the plume from an elevated release should be assumed to meander and spread uniformly over a 22.50 sector. The resultant equation is: 2.032 exp(-h 2/2oz 2)x/Q =Where x = distance from the release point (meters);other variables are as given in g(1).(3) The atmospheric diffuision model' for an elevated release as a function of the distance from the reactor, is based on the information in the table below.Time Following Accident Atmospheric Conditions

0-8 hours See Figure 1(A) Envelope o1" Pastluill diffusion categories based oil Figure A7 NI 'teorolog'

and Atomic I-netryo I tt(,1 , assuming various stack heights: vindspeed I me ier/see; uniform direction.

8-24 hours See Figure ItB) lEnvelope of Pasquill diffusion categories:

windspeed I meter/see:

variable direction within a 22.5 sector.1-4 days See Figure I[C) Envulope of Pasquill diffusion categories with the following relationship used to represent maximnnumn plume concentrations as a tumeltion of'distance: Atmospheric Condition Case I 40Y Pasquill A 601'} Pasquill C Atmospheric Condition Case 2 50% Pasquill CPasqtill D Atmospheric Condition Case 3 33.3',` Pasquill C 33.3% Pasquill D 33.3% Pasquill E Atmospheric Condition Case 4 33.3!, Pasquill 1)33.3, Pasquill E 33.3K- Pasquill F Atmospheric Condition Case 5 50r', Pasquill D 501? Pasquill F wind speed variable (Pasquill Types A. B. E.and F windspeed

2 memer/sec:

Pasquill Types C nid D windspeed

3 meter/sec)

variable direction within a 22.5" sector.4-30 days See Figure I(D) Same diffusion relations as given above- windspeed variable dependent on Pasquill Type used; wind direction

33.3" frequency in a 22.50 sector.11This model should be used until adequate site meteorological data are obtained.

In smote cases. avaitable information, such as meteorology, topography and geographical location.

may dictate the use of a more restrictive model to insure a conservative estimate of potential offtsite exposures.

1.3-3 I h. For BIWR's without stacks dhe almospheric diffusion inodel6,should be as follows: (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 dispersion produced by the turbulent wake of the reactor building in calculating potential exposures.

The volumetric building wake correction factor, as defined in section 3-3.5.2 of Meteorology and Atomic Energy 1968, should be used only in the 0-8 hour period; it is used with a shape factar of 1/2 and the minimum croms-sectional area ot the reactor building only.(2) The basic equation for atmospheric diffuision from a ground level point source is:x/0 =41U y oz Where the short term average centerline value of the ground level concentration (curie/rmeter

3)Q amount of material released (curie/see)

u windspeed (meter/sec)

O y =the horizontal standard deviation of the plume (nieters)

[See Figure V-I. Page 48, Nuclear Safrity. June 1961, Volume 2.Number 4. "Use of Routine Meteorological Observations for Estimating Atmospheric Dispersion," F. A. Gifford. Jr.]ID =the vertical standard deviation of the plume (meters) ISee Figure V-2, Page 48.Nuclear Safety, June 1961, Volume 2, Number 4."Use of Routine Meteorological Observations for Estimating Atmospheric Dispersion," F. A. Gifford, Jr.](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 /> the plume should be assumed to meander and spread uniformly over a 22.5" sector. The resultant equation is: 2.032 X/Q =azUX*Whe re x = distance from point of release to the receptor;other variables are as given in h(2).(4) The atmospheric diffusion model for ground level releases is based on the information in the table below.Ti me Following Accident Atmospheric Conditions

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 8-24 hours Pasquill Type F, windspeed

1 meter/see, variable direction within a 22.50 sector 1-4 days (a) 40% Pasquill Type D. windspeed

3 meter/see (b) 60% Pasquill Type F, windspeed

2 meter/sec (c) wind direction sector variable within a 22.50 4-30 days (a) 33.3% Pasquill Type C, windspeed

3 meter/sec (b) 33.3% Pasquill Type D, windspeed

3 meter/sec (c) 33.3% Pasquill Type F, windspeed

2 meter/sec (d) Wiind direction

33.3% frequency in a 22.5' sector (5) Figures 3A and 3B give the ground level release atmospheric diffusion factors based on the 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 S10-5 _......_ .....L ..÷ .7. -Vb.... .. ... .......10-4 S- .d_........___.....I

-1 --*.10 2 103 10410 Distance from Release Point (meters)1.3-5

-o : -T -r----.- ... -.... ................

II .........

' --10-3 10-io 2 iO 3 o o Distance from Release Point (meters)z -6 i

.% -'N p..1 ATMC.-LEXMATF&ULEASt.

.kSH9R1C--D##ISMQ

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

Tljfg.~FIGURE M()--t.................

.*10-10-5 E 0 010 10... .. ..Ii i.. ..I '*1* [ ....-4-2 I I " /'---S --------sk TfI1It40#

1 t I------------

L- ..I ýi I SI.:zzjzz~~I~

VL~~I XA¶N.AIX-I I Jpi i:.i:F [ I xI '%71 ..1 1f-NI 0l 10-8 102 103 Distance from Release Point (meters)1.3-7

  • .. 4 EUiVA"~bRIES

ATAMSW ON f-OR TtM..........

  • S* .,. ..~4-1 1 0-5i 10-IL -L.4 -4 T V : J. _ _7j I x___I Iv. I4N.N INi-- -------7:'.I~w z..L.J I 102 10 3.1o4 Distance from Release Point (meters)1.3-8 r , EtVAMD. RELEASE ATMOSPHERIC

DISPERSION

FACTORS FOR .FUMIGATION

qONDITIONS-ATMOSPHER

IC CdiNDITIONgS.

PASOUILL TYPE F WINDSPEED

I METER/SEC" F1GUHE It ......10-2 i;h 60 ..... ..0 C,, 10-... ..... .. .............

i i: T j .7 : i.....................................

,.. ..... .. ..-.I : a w~ H-F-9 WT N I,.A 7-n LTL 4-. 4--4 10-5 10-6 102 103 104 105 Distance from Release Point (meters)3..9)

w ~K" i 3 2.5 h----0 0 u 0 ra cc 5i FIGU^R'E 2 1 : T .I-._ ... .. ...M. :Ii-77 I t* I-I..* I I* I 0.5 0 102 St.ii 3; 1* I-i.1. iTd~3 6i 102 104 Dlsnme from Structur (won W~0.-

I A U V .-- ._.-.- ..I~ A VARIOUS TIN ESF LC14HN CI T FIGURE V(A)L-1 8-24 hours .~10a 3 10 10 Distance from Structure Imeters)10-5 L 102

-lA0TMOSERL~qIF

LLStOq Fibt~ .~ ~ .~... .. .. ..VARIOUS TIMES FOULOWING

IAC Ir INT~ .~-.. FIGURE 3B) 30 0-8 hours....................

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

~~. ......ta .I JI I. .... ......I. i 4 -t 103 10LL Dit6Ic fromzz Stutr (meters


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