ML20092K684
| ML20092K684 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 03/07/1984 |
| From: | TENNESSEE VALLEY AUTHORITY |
| To: | |
| Shared Package | |
| ML20092K683 | List: |
| References | |
| PROC-840307-01, NUDOCS 8406290014 | |
| Download: ML20092K684 (17) | |
Text
Sequoyah Nuclear Plant Offsite Dose Calculation Manual Dates of Revisions Original ODCM 2/29/80*
Revision 1 4/15/80**
Revision 2 10/7/80**
Revision 3 11/3/80, 2/10/81 4/8/81 and 6/4/81**
Revision 4 11/22/82 (10/22/81 11/28/81 and 4/29/52**
Revision 5 10/21/82**
Revision 6 1/20/83**
Revision 7 3/23/83**
Revision 8 12/16/83**
Revision 9 3/7/84**
t
- Low Power license for Sequoyah unit 1
- RARC Meeting date 6406290014 840622 PDR ADOCK 05000327 p
9 7
II fjk *.P
-(1.1)
Q Xg=
(2/n) exp (-A x/u )
g Izk. (2nx/n) u J
j=1 k=1 where Xg = air concentration of radionuclide i,p Ci/m.
8 fjk = joint relative frequency of occurrence of winds in windspeed class j, stability class k, blowing toward this exposure point, expressed as a fraction.
Q = average release rate of radionuclide i, pCi/s.
g p = fraction of radionuclide remaining in plume, Figure 1.1.
Isk=, vertical dispersion coefficient for stability class k which includes a building wake adjustment, Izk = ~(a 2 + cA/n) III, where a is the vertical 9
zk zk dispersion coefficient for stability class k (m), e is a building shape factor (c=0.5), and A is the minimum building cross-sectional area (1800 m ),,,
a u)= agidpoint value of wind speed class interval j, m/s.
x= downwind distance, m.
n = number of sectors, 16.
Ag = radioactive decay coefficient of radionuclide i, se-1#.
2 nx/n = sector width at point of interest, m.
For determining the total body dose rate DTB
- X DFB (1.2) i g
i where DTB = total body dose rate, mres/y.
X1 = air concentration of radionuclide i, pCi/m.
3 DFBg = total body dose factor due to gamma radiation, aren/y 3
per pC1/m (Table 1.5).
Revision 9.
'm For datermining 'the skin dose' rate
.Ds =
Xij(DFSi +.1.11 DFyi)
(1.3) i where Ds= skin dose rate, mrem /y.
X11= air concentration of radionuclide i,#Ci/m3 DFSi= skin dose factor due to beta radiation, mrem /y per UCi/m3 (Table 1.5).
1.11 =,the average ratio of tissue to air energy absorption coefficients, mrem / mrad.
DF Y - = s gamma-to-air dose factor for radionuclide i, mrad /y per i
UC1/m3 (Table 1.5).
B.
Equations and' assumptions for calculating doses from radioiocines and particulates are as follows:
Assumptions 1.
Dose is to be calculated for the critical organ, thyroid, and the critical age group, infant.
2.
Exposure pathways from iodines and particulates are milk ingestion, ground contamination, and inhalation.
3..
The radioiodine and particulate mix is based on;the design objective, source term given in' Table 1.1.
4.
Basic radionuclide data are given in Table 1.2.
5.
All releases are treated as ground-level.
6.
Meteorological data are expressed as joint-frequency distributions-(JFD's) of wind speed, wind direction, and atmospheric stability for the period January 1972 to December 1975 (Table 1.3).
7.
Raw meteorological data for ground-level releases consist of wind speed and direction measurements at 10m and temperature measurements at 9m and 46m.
8.
Dose is to be evaluated at the potential offsite exposure point where maximum concentrations are expected to exist.
'9.
Real cow locations are not considered.
1 4-L.
9
'This section of the ODCM describes the methodology that will be used to perform these monthly calculations.
Doses will first be calculated by a simplified conservative approach (step 1).
If these exceed the specification limits, a more realistic calculation will be performed (step 2).
1.2.1 Noble Gases Step 1-Doses will be calculated using the methodology described in this step.
If any limits are exceeded, step 2 will be performed.
Equations and assumptions for calculating doses from releases of noble gases are as follows:
Assumptions 1.
Doses to be calculated are gamma and beta air doses.
2.
The highest annual-average X/Q based on licensing meteorology for ground level releases for any offsite location will be used.
3.
No credit is taken for radioactive decay.
4.
For gamma doses, releases of Xe-131m, Xe-133, Xe-135, Ar-41, and Kr-88 are considered.
5.
For beta doses, releases of Xe-131m, Xe-133, Xe-135, Kr-85, and Ar-41 are considered.
3 6.
Dose factors are calculat ed using dat a from TVA's nuclide library.
7.
The calculations extrapolate doses assuming that only 90 percent of total dose was contributed.
8.
A semi-infinite cloud model is used.
9.
Building wake ef fects on ef fluent dispersion are considered.
Equations For determining the gamma dose to air:
p Dy = (X/Q) 106 Q i DFyf (1.12) j l5 0.9 3.15 x 10' i Revision 5
-where:
Dy = gamma dose to air, mrad.
X/Q = hi;,uest annual
..tage relative concentration, 5.12 x 9
10 s s/m.
3 0.9 = fraction of total gamma dose expected to be contributed by -
these nuclides.
3 108 = pCi/Ci conversion factor 3.15 x 107 = s/yr conversion factor Qg = inonthly release of radionuclide i, Ci.
DFy! = gamma-to-air dose factor for radionuclide i, mrad /yr per 1
pCi/m3 (Table 1.5).
This equation then reduces to
~7 Dy =' 1.81 x 10 Qg DFy (1.13) 1 g
5 1
For detennining the beta dose to air:
(X/Q) 106 g pyp (3,34) 5 D =
O.9 3.15 x 107 where:
Dp = beta dose to air, mead.
9 X/Q = highest annual-average relative concentration, 5.12 x 8
3 10 s/m.
0.9 = fraction of total beta dose expected to be contributed by these nuclides.
3 106 = pCi/Ci conversion factor 3.15 x 107 = s/yr conversion factor Q. = monthly release of radionuclide i, Ci.
I 1
DF. = gamma-to-air dose factor for radionuclide i, mrad /yr per 1
pCi/m3 (Table 1.5).
This equation then reduces to:
D$ = 1.81 x 10 Q DF (1.15) 5 7
g pg i
Revision 9 L
Step 2 This methodology is to be used if the calculations in Step 1 yield dcses that exceed applicable limits.
Equations and assumptions for calculating doses to air from releases of noble gases are as follows:
Assumptions 1.
Doses to be calculated are gamma and beta air doses.
2.
Dose is to be evaluated at the nearest site boundary point in each sector.
3.
Historical onsite meteorological data from the period 1972-1975 will be used.
9 i
4.
All measured radionuclide releases are considered.
5.
A semi-infinite cloud model is used.
L 6.
Rad oactive decay is considered.
7.
Buildi,ng wake effects on effluent dispersion are considered.
I 8.
Dose factors are calculated using data from TVA's radionuclide libra y.
t Equations /
(
Equations for calculating air concentration, X, is the same as in Section 1.1.1, step 1, part A.
Air concentrations are calculated for the site boundary in each sector.
For determining the gamma dose to air D
= t, X,g DFy (1.16) 5 g
i l
where:
f D
= gamme dose to air for sector n, mrad.
3 Xni = air c ncentration of radionuclide i in sector n, pCi/m 1
DFYg = gamma-to-air dose factor for radionuclide i, mrad /yr per prt/m3 (Table 1.5).
t,= time period considered, yr i
P Revision 9.
-For determining the beta dose to air:
DFp (1.17)
Dp l= t, ni x
g n
i where:
Dp
= beta dose'to air for sector n, mrad.
n Xni = air concentration of radionuclide i in sector n, 3
pCi/m beta to air dose factor for radionuclide i, mrad /yr per DFSg = pCi/m3 t, = time period considered, yr j
'The sector having the highest total dose is then used to check compliance'with specification 3.11.2.2.
1.2.2 lodines and Particulates
. Step-1 Doses will be calculated _using the methodology described in this step.
If any. limits are exceeded, step 2 will be performed.
Equations and assumptions for calculating doses from releases of iodines'and particulates are as follows:
. Assumptions
- 1.
Doses are to-be calculated for the infant thyroid from milk ingestion and for the child : bone and ' teen g. i. tract from 7
vegetable ingestion.
2.
Real cow locations are considered for the milk pathway and nearest resident-locations with home-use gardens are considered for the vegetable pathway.
.3.
The highest annual-average D/Q based on 1972 to 1975 meteorological data for ground leve1' releases will be used for ingestion pathway 5l7 doses.
4.
No credit.is taken for radioactive decay.
5.
Releases of 1-131 are considered for ths milk pathway.
- Sr-90 releases are considered for the vegetable pathway to the child bone.
7 Co-58 releases are considered for the vegetable pathway to the teen g.i.: tract.
6.
.The calculations extrapolate doses assuming that only 90 percent of.the total dose was contributed.
7.
The cow is assumed to graze on pasture grass for the whole year.
I Revision 7
D-Ecuations For determining the thyroid dose from milk ingestion of I-131:
DF D/Q x 10s 5
DTH131
- 9 131 131 (0.9) 3.15 x 10' (1.18) where:
DTH131 = thyroid dose from I-131, mrem.
Q
= monthly release of I-131, Ci.
33g DF
= I-131 milk ingestion dose factor to infant, 7.24 x 1011 131 2
mrem /yr per pCi/m -s (Table 1.7)
~9 2,
9 D/Q = relative deposition rate, 2.96 x 10 m
I 0.9 = fraction of dose expected to be contributed by I-131.
3.15 x 107 = s/yr.
108 = pCi/Ci Equation 1.18 then reduces to:
l DTH'31 = 75.6 - Q333 9
1 i
For dete ining the boue dose from vegetable ingestion:
Q, DF, D/Q 108 g 39)
DBC =
s 7
3.15x10 (0.9) where:
5 DBC, = bone dose to child from Sr-90, mrem.
Q, = monthly release of Sr-90, Ci.
DF, = Sr-90 vegetable ingestion dose factor to child, t
2 1.36x10 a mrem /yr per pCi/m -s.
(As per Regulatory Guide 1.109 and NUREG/CR-1004 methodologies).
D/Q = relative deposition rate, 7.10x10- m 2, 9
7 3.15x10
= s/yr.
108
= pCi/Ci.
0.9,= fraction of total bone dose expected to be contributed by Sr-90.
Equation 1.19 then reduces to 9
DBC, = 3406-Q, Revision 9
1 F
For determining the gastrointestinal (g.i.) tract dose from vegetable ingestion:
8 D/Q 10 DGI c
c (1.20)
T = (0.9) 3.15 x 10' Where:
DGIT = teen g.i. tract dose from Co-58, mrem Q = monthly release of Co-58, Ci c
DF = Co-58 vegetable ingestion dose factor for the teen g.i.
C 8
2 1
tract, 3.87 x 10 mrem /yr per pCi/m -s.
(Regulato ry Guide 1.109 and NUREG/CR-1004 methodologies.)
7 b/Q=relativedepositionrate,7.10x10~8 2
m 9
'3.15 x 107 = s/yr I
108 = pCi/Ci 0.9! = fraction of total g.i. tract dose expected to be contributed by Co-58 Equation 1.20 then reduces to 1
DGIT = 0.97 Q 9
c
'e l
l t
Revision 9
-15a-
Step 2.
This methodology is to be used if the calculations in step 1 yield doses that exceed applicable limits.
Doses for releases of iodines and particulates shall be calculated using the methodology in Section 1.1.1, step 1, part B, with the following exceptions:
1.
All measured radionuclide releases will be used.
2.
Dose will be evaluated at real cow locations and will consider actual grazing information.
The receptor having the highest total dose is then used to check compliance with specification 3.11.2.3.
Calendar quarter doses are first estimated by summing the doses calculated for each month in that quarter. Calendar year doses are first est{ mated by summing the doses calculated for each month in that year. Houever, if the annual doses determined in this manner exceed or approach the specification limits, doses calculated for previous quarters uith the methodology of section 1.4 will be used instead of the doses estimated by summing monthly results.
8 1.3 Dose Projections In accord nee with specification 3.11.2.4, dose projections will be performed This will be done by averaging the calculated dose for the most recent month and the calculated dose for the previous month and assigning that average dose as the projection for the current month.
1.4 Quarterly and Annual Dose Calculations A complete dose analysis utilizing the total estimated gaseous releases for each calendar quarter will be performed and reported as required in Specifications 6.9.1.8 and 6.9.1.9.
Methodology for this analysis is the same as that described in Section 1.1.1, except that real pathways and receptor locations (Table 1.4) are considered. In 9
addition, meteorological data representative of a ground level release for each corresponding calendar quarter will be used. This analysis will replace the estimates in Section 1.2.
At the end of the year an annual dose analysis will be performed by calculating the sum of the quarterly doses to the critical receptors.
1.5 Gaseous Radwaste Treatment System Operation The gaseous radwaste treatment system (GRTS) described below shall be maintained and operated to keep releases AI. ARA.
1.5.1
System Description
A flow diagram for the GRTS is given in Figure 1.3.
The system consists of two waste gas compressor packages, nine gas decay tanks, and the associated piping, valves, and instrumentation. Gaseous Revision 9 l
wastes are received from the following:
degassing of the reactor
~
coolant and purging of"the volume control tank prior to a cold shutdown, displacing of cover gases caused by liquid accumulation in the tanks connected to the vent header, and boron recycle procesc operation.
1.5.2 Dose Calculations Doses will be calculated monthly using the methodology described in Section 1.2.
These doses will be used to ensure that the GRTS is operating as designed.
I i
i Revision 8
-16a-8
e TABLE 1.4 SON - RECEPTOR LOC AT lO N S e
DISTANCE
[LEVATION CHl.0VER-Q 0-DVER-Q POINT SECTOR (M)
IM) 4S/M. 33 (1/M 23 1 LAND SITC 80VNOARY N
950.
-6.
5.12E-06' 1.29E-08 2 L AND SITC BOUNDARY NNC 2260.
-6.
1.93t=06 S.2nE-09 3 L AND SITC B0UNDARY NC 1910.
-6.
2.32t-06 6.33C-09 4 L AND SITC BOUNDARY ENE 1680.
-6.
1.120-06 2.64E-39 5 L AND Slf t B0UNDARY C
1S70.
-6.
7.10E-07 1.46C-09 6 L AND SITC BOUNDARY ESC 1460.
-6.
7.98t-07 1.58E-a9 7 LAND SITC B0UNDARY SC 1460.
-6.
- .14t=07 2.41C-09 8 L AND SITC BOUNDARY SSC 1550.
-6.
1.34E-06 3.23C-09 9 L AND SITC SOUNDARY 1570.
-6.
2.375-06 4.leC=09 le LAND SITC BOUNDARY SSW 1840.
-6.
4.51C-06 9.26t=09 11 L AND SITC B0UNDARY SW 2470.
-6.
1.38t=06 2.63C-09 12 L AND SifC ROUNDARY WSW 930.
-6.
2.93C-06 3.N6E-09 13 LAND SITC BOUNDARY W
670.
-6.
3.630-06 3 74C-09 14 L AND $1TC BOUNDARY WNW 660.
-6.
2.49[-C6 2 44t=09 1S L AND SITC BOUNDARY NW 660.
-6.
2.85E-06 3.67C-09 16 L AND SITE ROUNDARY NNW 730.
-6.
3.95E-06 6.59E-09 17 RfS10CNfeGAROCN N
1370.
O.
2.9AC-06 7.10t=09 18 RFSIDENT NNC 2710.
C.
1.49r-c6
- 3. set =09 19 RESIDENT.GAROCN BEEF NC 3430.
15.
1.0lf-06 2.33F=09 30 RESI0 TNT,GAROtN ENC 2290.
S.
7.13t=07
- 1. S if. - 0 9 21 RCSIOCNT E
1790.
8.
S.85t-07
!.lRC-09 22 RESIOfNT CSC 1790.
46.
S.86E-07 1.14t=09 23 RES!0 TNT SC 1680.
3.
7.42t-07 1.92C-09 24 RESIOCNT,GARDENe8ECF SSE 2210.
46.
7.99t=07 1 79E-09 2$ RESIDENT 2020.
O.
1.6SE-06 2.75[-09 26 R[SIDENieGARDEN
$$W 2670.
C.
2.66C-06 4 92C-09 27 RESIO!NT SW 3010.
C.
1.04t-06 1.P8E-09 24 RESIOCNfoGAROCN WSW 1140.
8.
2.09t=06 2.67C-09 29 RESIDENieGARDEN b
1750.
47.
R.53C-07 7.82C-10 30 RESIDENieG ARDENetCW WNW 1750.
12.
S.71t=07 4.98[-10 31 RCSIOCNT NW 1840.
11.
1.2SC-06 1 50E-09 32 RESIDENT NNW 800.
O.
3.420-06 S.67E-09 33 G AROCN,8CEF NNE 3010.
O.
1.28C-06 3.24[=09 34 CARotN C
2630.
9.
3.3RE-07 6.14E-10 3S GA40t4 ISC 1940.
29 S.25t=07 9.91[-10 36 CAROCN SC 3010.
47.
3.19E-07 7.160-10 37 GA40CN 2290.
O.
1.3RE-06 2.22L-09 38 G ARDEN SW 3320.
O.
9.10t=07 1.S9[=09 39 GA40C4 NW 1880.
11.
1.19C-06 1.42C-09 40 GARDEN NNW 1750.
17.
1.56t=06 1 590-09 el OfEF ENE 2130.
14 7.92L-07 1.77t=09 42 SttF C
2130.
17.
4.S7C-07 8.78E-10 43 BCCF CSC 3030.
53.
2.76[-07 4.690-10 44 BEfF SC 2630.
90.
3.88C-07 9.03E-10 45 RECF WSW 2060.
17.
R.7At-07 1.ctC-09 46 RECF W
6RD.
O.
3.SSt=06 3.6b[-09 47 SECF b4W 670.
O.
2.43C-06 2 38t=09 4A REEF NW 670.
O.
2.7AC=06 3.59E-09 49 MILR COW ADULioRECF N
9120.
O.
6.1Fr=07 1 10E-09 St MILR C0W ADULT NNE 4380.
O.
7.SSt=07 1 69C-09 St MILM COW ADULT NC 5220.
47.
5.59E-07 1 32E-09 S2 MILM COW ADULie8CCF SSW 3580.
6.
l.76C-06 2 96t-09
$3 mILR C0W ADULT NW 1980.
S.
S.610-07 6.09[-10 S4 MILM 804f ADULT SSC 5340.
29.
2.28C-07 3.89t-10 SS MILM $04f A0 ULT S
SS30.
37.
4.07C-07 4.81C-10 56 MILM 5047 TCEN SC 2940.
64.
3 300-07 7.4AC-10 Revision 9
Tabic 1.4a Deleted by Revision 9
b.
During any calendar year to 13 mrem to the total body and to 510 mrea-to any organ.
To ensure compliance, cumulative dose calculations will be performed at least once per month according to the following methodology.
2.3.2 Monthly Analysis Principal radionuclides will be used to conservatively estimate the monthly contribution to the cumulative dose. If the projected dose exceeds the above limits, the methodology in Section 2.3.3 will be implemented.
3 The 11 nuclides (listed below) contribute pore than 95 percent of the dose to the total body and the three most critical organs for each pathway. The critical organs considered for fish ingestion are the 9
gastrointestinal tract (GIT), bone, and liver. The critical organs for water ingestion are the GIT, bone, and thyroid.
7 H-3 Co-58 Sr-90 Cs-134 P-32 Co-60 Nb-95 Cs-137 Fe-55 Sr-89 I-131 A conrervative calculation of the monthly dose will be done according to the following procedure. First, the monthly operating report containing the release data will be obtained and the activities released of each of the above eleven radionuclides will be noted. This 3
information will then be used in the following calculations.
2.3.2.1 Water Ingestion The dose to an individual from ingestion of water is described by the following equation.
11 5
D)=
(DCF)g)
I ), rem (2.11) g i=1 Revision 9
where:
th D
= dose for the j organ from eleven radionuclides, rem j
j the organ of interest (bone GI tract and total body).
=
.95 conservative correction factor, considering only eleven
=
radionuclides.
1 -
th DCF 3 = organ of adult or child from the icriticalingestiondosecommitmentfactrfrthej t
radionuclide rem /pci, see attached as Table 2.1.
th I.. = monthly activity ingested of ghe i radionuclide by the t
IJ critical age group for the j organ, pCi.
5
-I is described by gj gj = A; V;j-(30)
,pci (2.12)
I Pd (7.34 x 10'o7 where:
th A.
= activity released of i radionuclide during the month, 1
pCl.
Vt. = maximum individual's water consumption rate corresponding J
to the age group selected for the critical DCF above 5
(Adult: 2000 mL/d, Child: 1400mL/d;RegulatorhdGuide 1.109) 30 = days per month 3
F = average river flow at' Chickamauga Dam for the month (cubic feet per second) d =-fraction of river flow available for dilution (1/5) 7.34x1010 = conversion from cubic feet per second to milliliters per month.
The dose equation then becomes 11
~~'
D = 2.15 x 10~C (V x DCF)tj x A, mrem (2.13) 5 j
g F
i=1 1considering the conversion factor from rem to mrem. Revision 5
.