ML19269E703
| ML19269E703 | |
| Person / Time | |
|---|---|
| Issue date: | 06/30/1979 |
| From: | Wing J Office of Nuclear Reactor Regulation |
| To: | |
| References | |
| NUREG-0570, NUREG-570, NUDOCS 7906290498 | |
| Download: ML19269E703 (34) | |
Text
N U R EG-0570 TGXIC VAPOR CONCENTRATIONS IN THE CONTROL ROOM FOLLOWING A POSTULATED ACCIDENTAL RELEASE O
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4 NU REG-0570 TOXIC VAPOR CONCENTRATIONS IN THE CONTROL ROOM FOLLOWING A POSTULATED ACCIDENTAL RELEASE Prepared by James Wing Manuscript Completed: May 1973 Date Published: June 1979 Division of Site Safety and Environmental Analysis Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D.C. 20555 2147 309
Toxic Vapor Concentrations in the Control Room following a Postulated Accidental Release P3Le 1.
Introduction 1
2.
CalculationofVapordoncentrationsinAir 3
2.1 Mass Transfer 3
2.1.1 Surface Area of a Spill 4
2.1.2 Vaporization of Low-Boiling-Point Liquids and Compressed Gases 5
2.1.2.1 Atmospheric and Solar Radiation 6
2.1.2.2 Forced Convection of Air 7
2.1.2.3 Earth Conduction 8
2.1.2.4 Vaporization Rate 9
2.1.3 Evaporation of Normal-Boiling-Point Liquids 10 2.1.3.1 Gaseous Diffusion in Confined Areas 10 2.1. 3. 2 Mass Transfer by Forced Convection 12 2.1.4 Comparison of Calculation with Empirical Data 13 2.1.4.1 Annual Evaporation of Water 13 2.1.4.2 Empirical Formulas for Evaporation of Water 14 2.2 Vapor Dispersion 17 2.2.1 Instantaneous Puff Release 17 2.2.2 Continuous Plume Diffusion 19 2.2.3 Standard Deviations and Stability Conditions 20 2.3 Control Room Air Exchange 22 2.4 Summary of Vapor Concentration Calculations 22 2.4.1 Calculation of Concentrations 22 2.4.2 Summary of Conservatisms 23 3.
Toxic Substances 24 3.1 General Considerations 24 3.2 Sources of Physical Data 25 4.
Acknowledgements 25 2147 310
P891 5.
Bibliography 26 Appendix.
Physical Properties of Toxic Chemicals 31 2147 311
1.
Introduction An accidental release of a toxic gas can harm or even kill the individuals who are expose 6 to the gas beyond its toxicity limits.
Under most circumstances, the consideration of such an event would fall in the category of industrial safety.
There are, however, situations that can be postulated in which a toxic gas release could interfere with the safe operation of a nuclear plant.
(See General Design Criterion 19, Appendix A, Part 50, Title 10, Code of Federal Regulations).
For instance, a catastrophic release of chlorine from a rail car, in which the entire load of chlorine is spilled, could lead to the incapacitation or even death of the control room operators.
This is a consequence of low probability (Hornyik; Murphy et al.; Simmons et al.).
A number of events may have to occur in a sequential fashion to produce dangerous levels of chlorine within the control room.
The chlorine tank must rupture, the wind direction must be toward the control room fresh air inlets, and the flow conditions must be such as to allow the chlorine to reach the inlets with concentrations stfficiently high to overcome the operators.
The staff at U.S. Nuclear Regulatory Commission (NRC) has concieded that, notwithstanding the low probabilities, this type of an accident scenario should be considered in its safety evaluation of nuclear reactor plants.
The NRC staff has developed a number of guidelines and criteria to assure that the requirements of General Design Criterion 19 are met.
These can be found in Standard Review Plans 2.2 and 6.4 and in Regulatory Guides 1.78 and 1.95.
One aspect of the safety evaluation of nuclear 2147 312
reactor plants is the assessment of the toxic vapor concentrations that may result from a liquid spill.
The present report summarizes an acceptable method for such an assessment, and lists some typical toxic substances and their pertinent physical properties.
Many of the assumpticns underlying the mathematical formulation in this report may seem rather simplistic and arbitrary.
However, it is believed that they are reasonably conservative.
As socn as more realistic models or direct experimental data become available, the present treatment will be modified.
It should also be pointed out that the probabilistic nature of the catastrophic spill of toxic chemicals, during transportation and in storage, is not considered here.
That is, the frequency of shipment and cargo size of each toxic chenical past the nuclear plant site, the accident rates of on-site release and of each shipment type (trucks, rails, barges, etc.), the distribution of wind speeds and directions, and the uncertainty of the weather conditions will not be included in the assessment of vapor concentrations.
The accident probabilities of trucks, rails, and barges, per vehicle mile, have been estimated by Directorate of Regulatory Standards.
3 An analysis of the risks in the water transportation of hazardous materials has been made by the Committee on Hazardous Materials.
The statistical nature of the hazards to nuclear power plants from surface traffic accidents and from off-site release of toxic vapors has been extensively studied by Hornyik.
The risk of catastrophic spill of chlorine during transportation has been investigated by Murphy et al. and Simmons et al. 2147 x13 s
2.
Calculation of Vapor Concentrations in Air In a postulated accident, it is assumed that the entire container of the toxic substance ruptures.
This is the worst case compared with partial ruptures where the content leaks out in a steady flow.
Part of the substance will vaporize and diffuse into the atmosphere.
The vapor is assumed to form a cloud or a plume, which will disperse into the atmosphere and, simultaneously, move toward the control room air intake.
The vapor concentration is further reduced by dilution with the air in the control room ventilation system.
Any interaction that can take place rapidly between the spilled substance and the environment (air, earth, water) must be identified and evaluated.
For example, fast chemical reactions may generate toxic gaseous products, or may reduce the hazard of the spilled substances.
2.1 Mass Transfer The volatility of a substance is a direct function of its vapor pressure.
Most solid substances have relatively low vapor pressures at a high ambient temperature of 40 C.
Compressed gases, liquefied gases, and many liquids have sufficiently high vapor pressures, so that, when released to the atmosphere, they will either,aporize or evaporate.
For compressed and liquefied gases and those liquids whose normal boiling points are far below the ambient temperature, instantaneous flashing (rapid formation of a cloud) will first take place.
The remaining liquid will vaporize by drawing heat from the surroundings.
On the other hand, if the normal boiling point is above the ambient temperature, the liquid will evaporate into the atmosphere.
2147 3l4 2.1.1 Surface Area of a Spill The rate of mass transfer, i.e., vaporization or evaporation, of a liquid into the atmosphere is, among other things, directly proportional to the surface area of the spill.
Let us approximate the initial shape of the liquid body by a cylinder, with the height equal to the radius of the base.
The liquid spreads quickly by gravity to a thin pancake on ground.
Its surface area, A, may be estimated by the following equation (Van Ufden):
IP P)] 1/2 }
(2.1-1) 2t [ho 2
A(t) ' n { r E
+
g pg and V =nr (2.1-2) g g
where initial radius of the spill (cm) r
=
g 2
g gravitational ccnstant = 981
,c-sec )
=
3 volume of the spill (cm )
V
=
g 3
density of the liquid or gas (g/cm )
pg
=
3 density of air (g/cm )
=
p time (sec) t
=
To be sure, the rate of area spread depends on the surface tension, viscosity, and density of the liquid.
A more sophisticated formula should be developed to include these physical properties.
At present, eq. (2.1-1) is adopted as a first approximation for the spill area.
Equation (2.1-1) also neglects the mass loss, atmospheric turbulence, and temperature and wind effects.
Note that V is the volume of the liquid g
spill remaining after instantaneous flashing to puff has taken place. 2147 315
The surface area, however, does 'iot in reality expand indefinitely as eq. (2.1-1) indicates.
During vaporization and evaporation, the liquid continuously loses mass, and hence the total volume reduces with time.
Thus, the liquid will attain a maximum surface area at some time depending upon the mass transfer rate.
If the spill occurs on a surface that will restrict the spread of the spill under all postulated accident conditions, e.g., inside a building or within a domed area, then the maximum area of the spill can be calculated.
In most cases, the condition of the ground cannot be described accurately, and therefore, the maximum area of the spill cannot be easily computed.
In these cases, the maximum area of spill is estimated from the initial volume by assuming a spill thickness of 1 cm.
It is believed that this minimum thickness is realistic and still conservative.
2.1.2 Vaporization of Low-Boiling-Point Liquids and Compressed Gases For the liquids and compressed gases whose normal boiling points are lower than the ambient temperature, the heat balance in the instantaneous puff formation is given by the following equation:
m Cp (T -T)
"vo H (2.1-3)
=
T g
b y
where m
=
T total initial mass of the liquid (g)
C heat capacity of the liquid (cal /g C)
=
p T
ambient temperature ( C)
=
g T
=
b n rmal boiling point of the liquid ( C) < T g
mass of the instantaneously vaporized liquid (g) m
=
g H
heat of vaporization of the liquid (cal /g)
=
y 2147 316
_s.
For compressed gases such as liquid nitrogen and helium, To should be the actual storage temperature of the liquid. 'For other gases and liquids, it is assumed that they have attained the ambient temperature is the before the instantaneous flashing takes place.
The ratio myg/mT maximum fraction of the liquid which forms the instantaneous puff.
2.1.2.1 Atmospheric and Solar Radiation
~
- o), will vaporize by absorption of The remaining liquid, (mT v
heat from atmospheric (long-wave) radiation and solar (short-wave) radiation, convection of air, and ground conduction.
Reflection of radiation by the liquid surface and re-emission of radiation by the liquid body are ignored here, as quantitative treatment on these two subjec^a is lacking for various liquids except water (Koberg; Patterson et al.).
If the liquid is spilled inside a building, the direct solar radiation may be disregarded.
Tne atmospheric and solar radiation fluxes may be computed using the existing formulas (Koberg; Patterson et al.).
However, there is more confidence in employing the observed or empirical data available in the literature.
The maximum expected solar and atmospheric radiation fluxes at various north latitudes (30 to 45 ) for each month of the year have been tabulated (Langhaar; Perry and Chilton, 12-21).
These clear-day values include direct and scattered radiation on a horizontal surface, and are based on analyses of Weather Bureau records for a number c states throughout the United States.
Both the daily average and noon 2
values are presented.
The highest value is 275 cal /m -sec at noon on June 1 and July 1 at 30 N.
On cloudy days, the clear-day fluxes are
~6-2147 M 7
reduced by (0.61S + 0.35), where S = number of hours of sunshine divided by the total number of possible sunshine (Fritz and MacDonald).
The atmospheric and solar radiation fluxes have also been experi-mentally measured at various locations in the southwestern region, i.e.,
latitude 27 N to 40 N (Fritz and MacDonald; Koberg).
These values are daily averages for everyday of each month.
The maximum values are (at 2
2 Roostvelt Reservoir, AR) 115 cal /m - sec and 97 cal /m - sec for atmospheric and solar radiation, respectively.
It may be interesting to compare the experimental data of the atmospheric radiation flux with a calculated value using the following modified Brunt's formula (Koberg):
qy SB (C) + 0.0263 JpH 0) (T + 273)4 (2.1-4)
=
p a
where qg = atmospheric radiation flux (cal /m sec)
-0 SB = Stefan - Boltzmann constant = 1.355 x 10 o
2 4
cal /m sec K T
= ambient temperature ( C) a C
= 0.735 for Ta > 34 C j
pH 0 = vapor pressure of water (mb'c) 2 For T = 40 C and assuming 50% relative humidity in air, pH 0 = 38.3 a
2 2
mbar (List p. 347).
qy is computed to be 117 cal /m sec, which is comparable to the experimental value cited above.
2.1.2.2 Forced Convection of Air The heat flux, q, due to forced convection of air over the spill c
is:
2147 318 bc (Ta - Tb)
(2.1-5) qc
=
2 where hc is the heat transfer coefficient (cal /m - sec - C).
The heat transfer coefficient of air blowing over a flat surface has been computed '8olz and Tuve, p. 538) for a mean air temperature of 21 C.
The computation was based on the following heat transfer equation:
0.6 k
C
~
h (constant) [ ( " P)
(ak) c vhere k = thermal conductivity of air at Ta (cal /cm sec C)
L = characteristic length (m) u = wind velocity (m/sec) p = viscosity of air (g/cm sec)
C = heat capacity of air (cal /g C) a p = density of air (g/cm )
The computed values of hc are tabulated for several assumed wind velocities (Bolz and Tuve).
The value extrapolated for the wind velocity 2
of 1 m/sec is 1.6 cal /m sec C.
2.1.2.3 Earth Conduction The heat transfer by earth conduction, qd, is given by the following equation (Bird es al., p. 354),
qd kE (TE b
E t/pE C
- T ) [n k
=
PE where kE = thermal conductivity of earth's crust (cal /cm sec C) pE = density of earth's crust (g/cm )
CPE = heat capacity of earth's crust (cal /g C) t = time (sec) 2147 319
TE = ground temperature ( C)
-3 The avere.ge thermal conductivity of earth's crust is 4 x 10 cal /cm sec C (Lange, p. 1503).
This may be compared with the thermal conductivities
-3 of limestone, sandstone, and granite, which range from 1.36 x 10 cal /cm
-3 sec C to 9.5 x 10 cal /cm sec C (Weast, E-3).
The overall average density of earth's crust of various consistencies (dry, moist, mud, loose, and packed) is 1.52 g/cm3 (Perry and Chilton, 3-90).
The heat capacities of several substances resembling earth's crust (clay, granite, limestone, sand, stones, and bricks) vary from 0.191 to 0.224 cal /g C (Perry and Chilton 3-136).
-3 Using k = 4 x 10 cal /cm sec C, pE = 1.52 g/cm,
E and CPE = 0.2 cal /g C, eq. (2.1-7) becomes b
2 qd = 197 (T - T )/t (cal /m -sec)
(2.1-8)
E b
2.1.2.4 Vaporization Rate The rate of total heat transfer, in cal /sec, of the remaining liquid after instantaneous flashing is given by the following equation dQ = A (t) (a
+q
- 9)
(2.1-9) c d
dt
= A (t)
{ gr + hc (Ta - Tb) + 197 (TE - Tb)/tb}
(2.1-10) solar and atmospheric radiation fluxes.
where q
=
p The vaporization rate, (dm /dt), in g/sec, is then y
(dm /dt) = 1, (dj)
(2.1-11)
H dt
}
(2.1-12)
= A(t)
{q +bc (T -T )
- l9 (E -T) 2 a b b
H where m = mass of the vapor.
q 2147 320
2.1.3 Evaporation of (ormal-Boiling-Point Liquids When exposrd to the atmosphere, the liquids with normal boiling points above the ambient temperature will evaporate by diffusion into the air.
The main driving force here is the vapor pressure difference, i. e.,
concentration gradient, between the liquid phase and the aic As the liquids may be spilled in either a confined area with or without ventilation, or in an open area with wind blowing over the liquid surface, the appropriate formula for the mass transfer in each case will be presented.
2.1.3.1 Gaseous Diffusion in Still Air The rate of a vapor diffusing into still air may be computed from the Fickian diffusion equation (Bird et al., p. 596)
(dm /dt) = A(t) p pv 10 hl/2 4
( 2.1-13 )
where A(t) = surface area of the spill at time, t, (m )
p = v.por pressure of the lioiid (mm Hg)
P= inbient atmospheric pressure (mm Hg) 3 pv = vapor density of the liquid (g/cm )
2 D = diffusion coefficient of the liquid into air (cm /sec).The experimental values of D for a number of compounds diffusing into air have been tabulated (Bolz and Tuve, p. 546; Perry and Chilton, 3-222).
They vary from 0.03 to 0.2 2
cm /sec.
The diffusion coefficient, D f a gas A diffusing into a gas B AB, may also be estimated by the following formula (Bird et al., p. 511, Reid &
Sherwood, p. 523; Perry.and Chilton, 3-230) (sne also Sissom and Pitts, p.
189): 2147 32J
DAB = 0.0018583 (T + 273)3/2 (
)l/2 a
A B
(2.1.-14)
Po O
AB AB where MA = m lecular weight of gas A (g/ mole)
MB = m lecular weight of gas B (g/ mole)
P = atmospheric pressure (atm) o=
Lennard - Jones parameter DAB = dimensionless function of temperature and intermolecular potential field E AB The Lennard-Jones parameter is empirically estimated to be an arithmetic mean of the two gases:
AB " ("A + "B) /2 (2.1-15)
The intermolecular potential field is empirically estimated to be a geometric mean of the two gases:
EAB = (EA B (2.1-16)
E)
Toe values of o, E, and 0 for a few compounds are available in the literature (Bird et al, p. 744; Reid and Sherwood, p. 524, p. 632).
Eventually, the air space in the confined building will be saturated with tb.e toxic vapor of the spill, and the vapor concentration will approach the following value (assuming ideal gas behavior of tne vapor):
Ps M Cs
=
Rg (Ta + 273)
(2.1-17) 3 where Cs = saturation concentration (g/cm )
R = universal gas constant g
2147 322 e-.-
M = colecular weight of the liquid (g/ mole)
T = ambient temperature ( C) a P = saturation vapor pressure of the liquid (mm Hgj 3
This would be the maximum vapor concentration of a liquid that is spilled in a confined space, such as a basement.
2.1.3.2 Mass Transfer by Forced Convection The evaporation of a liquid in an open space with wind or in a confined area with good ventilation can be described as a mass transfer process by forced convection.
The evaporation rate may be calculated by the followir formulas (Eckert and Drake, pp. 470-476):
(dm /dt) = h M A(t) (P - P )/Rg (T + 273)
(2.1-18) y d
s a
a where, for a laminar flow (Eckert and Drake, pp. 176, 177, 475):
=0.664f(Re)12(Sc)13 h
(2.1-19) d and for a turoulent flow (Eckert and Drake p. 215):
d = 0.037 f (Re)0.8 (Sc)13 (2.1-20) h Re = Reynold number = l u p/p Sc = Schmidt number = p/Dp h = mass transfer coefficient (cm/sec) d R = universal gas constant g
2 0 = diffusion coefficient (cm /sec) u = wind speed (cm/sec) 3 p = density of air (g/cm )
2147 323 L = characteristic length (cm) p = viscosity of air (g/cm sec)
M = molecular weight of the liquid (g/ mole)
P = saturation vapor pressure of the liquid at temperature s
Ta (mm Hg)
P = actual vapor pressure of the liquid in air (mm Hg) a For water, P may be computed from the relative humidity (List, a
- p. 347).
For other liquids, P w uld normally be zero.
r The diameter of the spill area may be taken as the characteristic length, L.
The spill area and thus the characteristic length vary with time (eq. (2.1-1)).
2.1.4 Comparison of Calculations With Empirical Data A few calculations of evaporation rates are compared with the available empirical data.
However, the empirical observations were made on evapora-tion of water from confined sources, such as pools and ponds, where the surface areas are already fixed.
Therefore, it is not possible to check the dynamic process of simultaneous spreading and evaporation of the liquid.
2.1.4.1 Annual Evaporation of 5/ater The annual evaporation of water from a standard evaporation pan of the Weather Bureau has been measured at many stations throughout the United States.
The data for the period of 1946-1955 have been collected (Kohler et al.).
2147 324 The annual mean temperatures, wind speeds, and relative humidities of several geographic regions of the United States have been compiled (Lerner, pp. 182-193).
Using this information, it is possible to calculate the annual evaporation of water by eqs.
(2.1-18) and (2.1-19).
A comparison of the calculated annual evaporation using eq. (2.1-19) (laminar flow) with the experimental data for ten widely separated locations is presented in Table 1.
In the calculations, the arithmetic mean of the relative humidities was used for each location, and the characteristic length was 1.2 m (diameter of the standard evaporation pan of the National Weather Service).
The agreement is good, with the maximum variation being within a factor of 2.
2.1.4.2 Empirical Formulas for Evaporation of Water Several formulas for the prediction of evaporation of water from pools have been developed empirically (C',,w,11-4; Merritt; Patterson, et al., Davis and Sorensen).
These are summarized in Table 2 together with the calculated evaporation rates for water at 38 C with a relative humidity of 10% and wind speed of 1 m/sec.
The experimental datum obtained under this condition for evaporation on drying trays (Bolz and Tuve) is also shown.
Using L = 1.2 m, the evaporation rates computed from eqs. (2.1-18) and (2.1-19) (laminar flow) are also presented in Table 2.
The empirical formulas predict evaporation rates ranging from 0.070 2
2 to 0.44 g/m sec, with an average of 0.26 g/m sec.
The agreement between the empirical formulas and the experimental value, and hence ens. (2.1-18) and (2.1-19), is within a factor of 2 in most cases.
The empirical 2147 325
Table 1 Comparison of Calculated Evaporation Rates cf Water With Experimental Data
- Location Annual Annual Average Annual Average Average Relative Evaporation Temperature Wind Speed Humidity (cm)
(*C)
(cm/sec)
(%)
Experimental Eq. (2.1 -19)
High-Low Phoenix,AR 21.3 268 53-32 183 179 Los Angeles,CA 16.5 277 75-53 117 85 Denver,C0 11.1 402 69-41 81 91 Louisville, KY 13.1 371 81-59 91 66 New Orleans, LA 20.2 375 88-63 124 84 Portland, ME 7.2 393 80-60 61 46 Albuquerque, NM 13.8 398 57-37 137 126 Bismark, ND 5.2 478 78-56 86 49 El Passo, TX 17.4 434 52-35 183 177 Seattle, WA 10.6 420 83-74 61 43
- Data for annual average temperatures, wind speeds, and relative humidity obtained from Lerner, pp. 182-193.
Data for annual evaporation from Kohler et al.
2147 326
- 15 _
Table 2 Comparison of Calculated Evaporation Rates of Water by Several Formulas Ambient Temperature = 38 C Relative Humidity = 10%
Wind Speed = 1 m/sec Evaporation Rate 2
Formula Equation (g/m sec)
FitzGerald E = (0.4 + 0.199 w) (ps pa) 0.44 Meyer, small pool:
E = 0.5 (1 + 0.1 w) (ps pa) 0.32 large reservoir:
E = 0.37 (1 + 0.1 w) (ps pa) 0.23 Horton E = 0.4 {ps [2-exp(-0.2w)1 pa}
0.29 Rohwer E = 0.771 (0.44 + 0.118w) (1.465-0.0186P)
(ps pa) 0.26 Harbeck E = 0.0599 w (ps pa) 0.070 Patterson E = 0.345 (1 + 0. lw) (ps pa) 0.22 Kohler, Davis E = (0.37 + 0.1 w) (ps pa)0.88 0.29 Experimental Bolz and Tuve Drying trays 0.15 Eq. (2.1-19) 0.14 E = evaporation rate (inches /01-)
w = wind speed (miles /hr)
P, ps, pa in inches Hg.
expressions do not account for the ambient temperature, except through its influence on vapor pressures, or for the reservoir size.
Both of these factors are accounted for in eqs. (2.1-18) and (2.1-19).
Under these circumstances, it is not expected that the agreement between the empirical expressions and eqs. (2.1-18) and (2.1-19) to be better than a factor of 2.
2.2 '/apor Dispersion The vapor from instantaneous flashing (puff) and from continuous vaporization or evaporation (plume) moves in the direction of the wind and disperses by diffusion into the atmosphere.
The dispersion is assumed to follow a Gaussian distribution for short travel times (a few minutes to one hour).
That is, an individual puff may or may not be well-described by a Gaussian formulation, but an ensemble of puffs is assumed to disperse in a Gaussian function.
This diffusion model is applicable only to the vapors whose densities do not differ greatly from that of air (Slade).
The wind is assumed to be in the direction from the source of spill to the control room air intake.
It should be noted that topological variations of the terrain between the source and receptor are ignored in this treatment.
2.2.1 Instantaneous Puff Release The diffusion equation for an instantaneous puff with a finite initial volume and a receptor at the air intake is given by the following equation (Yanskey, et al., 3-2; Slade, p. 115): 2147 328
2 2
X(x, y, z, b) =
. exp {
2.o 2 + b')
Q 1x (2n)3/4 o
aXI YI ZI XI YI I
(z+h)2'
}
(2.2-1)
. { exp 1
(z-h)2'
+ exp 1
~2o$
"Z$
Z 3
Where x = concentration (g/m )
Q = source strength (g) = myg XI' "YI' "ZI = adjusted standard deviations of the puff concentration in the horizontal along-wind (X), horizontal cross-wind (Y), and vertical cross-wind directions (Z), respectively (m).
x, y, z = distances from the puf f center in the X, Y, and Z directions, respectively (m).
z is also the effective above ground elevation of the receptor, e.g., the fresh-air intake of a control room.
b = effective above ground elevation of the source.
To account for the initial volume of the puff, it is assumed that
+
(2.2-2)
XI I
o 2
,2 2
o
=
g
,g (2.2-3) yg
{
9 ZI I * "o (2.2-4) 2 2
"XI oYI (2.2-5)
=
and letting x = x - ut (2.2-6) g 1/2 3/2 1/3 y
p (2.2-7) yg/(2 o = m g
where o = initial standard deviation of the puff (m) g c '7, o'y,
ZI = standard deviation of puff concentration in the o 2147 329
X, Y and Z directions, respectively (m) m
= mass of the instantaneously released puff (g) yg p = density of the puff (g/m )
y x = ground distance between the source of spill and receptor (m) g u = wind speed (m/sec) t = time after release (sec)
Then, eq. (2.2-1) may be used for the calculation of the center-line concentration where y = 0.
The fresh air intakes in nuclear power plants are usually situated on the top or sides of a building.
To account conservatively for building effects on the puff dispersion, eq. (2
.) is modified as follows.
For the vapors much heavier than air, z=h=0 (2.2-8) and for the vapors lighter than air, h is replaced by z in eq. (2.2-1).
2.2.2 Continuous Plume Diffusion The diffusion equation for the continuous release of a plume with a finite initial volume and a receptor at z above the grou.d level is given by the following equation (Yanskey et al., 3-39; Slade, p. 99):
2
}2 X(x,y,z,h) =
'P I (~ X ) } lexP [~
]
2n uo o
2 Y
Z 2c Z
y
+ exp[-({Z h
]}
(2.2-9) where o,
Z = standard deviations of the plume concentration in the Y and Z y
directions, respectively (m)
Q' = continuous source strength (g/sec) 2147 330
To give credit for the finite initial size of the spill, o here is y
yg )l/2 replaced by (c 2 + o 2
, where o is the effective width of the spill.
y yg Although the distribution of a circular spill of a liquid in the cross-wind direction is not a nornal function (it is of the form p = (1 - F )1 2 2
where - 1.0 $ F $ 1.0), o may be approximated by the following method yg (Turner):
yg ; r n !2 I
/4.3 (2.2-10) o where r = radius of the spill.
Similarly, oZ may be replaced by (o +0Z0) !
2 However, o may be assumed to be zero since it is usually Zo very small.
If r and Q' change significantly with time, they should be replaced by their mean values over suitably short time intervals.
Then the concen-tration calculations can be carried out with constant r and Q' over each time interval.
Again, to account conservatively for building wake and plume bypass around the receptor, it is assumed that, for the vapors much heavier than air, z=h=0, and for the vapors lighter than air, h is replaced by z in eq. (2.2-9).
2.2.3 Standard Deviations and Stability Conditions The average curves of o and o as a function of down-wind distance y
Z have been constructed for various weather stability categories (Hilsmeier and Gifford).
The stability categories, i.e., the Pasquill's types of weather condition, are defined as: 2147 331
Pasquill's Stability Category Weather Condition A
extremely unstable B
moderately unstable C
slightly unstable D
neutral E
slightly stable F
moderately stable G
extremely stable The curves for types E and F for release from a few minutes to 10 minutes are available in the reference (Hilsmeier and Gifford).
These conditions encompass the worst expected situation for nearly all the nuclear power plant sites.
The type G curve has been constructed by extrapolation (Yanskey et al., 3-6).
Calculations that are based on the type G curve are likely to be extremely conservative.
Although the Pasquill-Gifford curves are appropriate only for plumes, they may be assumed to be applicable for estimating the puff dispersion coefficients.
Alternatively, the power function approximations of Islitzer and Slade (Slade, p. 175) may be used for the distance from 100 t to 4 km.
The power function approximations, shown below, give much smaller dispersion coefficients than the Pasquill-Gifford curves.
Note that all these standard deviation curves and functions may not be applicable to distances shorter than 100 meters. 2147 332
Weather Condition o 'y o ';
Unstable 0.14 (x)0.92 0.53 (x)0.73 Neutral 0.06 (x)0.92 0.15 (x)0.70 Very stable 0.02 (x)0.89 0.05 (x)0.61 2.3 Control Room Air Exchange The ventilation layout of the reactor control building varies from plant to plant.
Conservatively, it is assumed that the outside air enters directly into the control room through an air intake.
The dilution factor, F, is given by:
F = 1 - exp (-Wr/V )
(2.3-1) p where 3
W = air flow rate in control room (m /sec)
V = control room air space (m )
r T = time duration (sec) 2.4 Summary of Vapor Concentrations Calculations 2.4.1 Calculation of Concentration The concentration of the toxic chemical, C, in g/m, at the air g
intake just outside the control room is the sum of the puff and plume concentrations at any instant.
The concentration, C, at the outside g
air intake at time t is C (t ) = mv, puf f ('^' 9) ti * (d* /dt)ti, plume (X/Q')
(2.4-1) g v
The concentration build-up inside control room C, in g/m, at time r
t is
$ 2!47 733
i-1) + [C (t ) - C (t.))] [1 - exp (-WT/V )3 C (t ) = C (t g j r g r
r i r
j - t.)
(2.4-2) where T = t j
2.4.2 Summary of Conservatisms In summary, the present method of estimating the vapor concentration of a toxic chemical in the control room following a postulated accidental release, contains several conservative assumptions.
Among them are the following:
1.
The entire inventory or cargo in one container is released; 2.
The area of the spill is predicted by eq. (2.1-1), with a minimum thickness of I cm; 3.
The vapor, in the form of a puff or plume, moves directly toward the air intakes of the control room; 4.
The center-line concentration of the vapor is calculated using the formulas in section 2.2.
The following values may be assumed in the calculation of vapor concentration using the formulas in this report.
2 Diffusion coefficient (if not available), D 0.2 cm /sec 2
Solar and atmospheric radiation fluxes 275 cal /m -sec Air exchange rate in control room (if not known),
W/V 1/hr r
The site metereological parameters, based on the available data, should be used.
It is recommended that a few combinations of the ambient temperatures, Pasquill types, and wind speeds be assumcd to give the most conservative assessment of the toxic vapor concentrations.
A plot of the
, 2147 334
vapor concentration inside the control room as a function of time after the pasutlated chemical spill should be helpful.
3.
Toxic Substances 3.1 General Considerations There are six broad classes of chemical substances thct are hazardous to human beings, namely, toxic, asphyxiate, explosive, corrosive, flammable, and radioactive substances.
When an explosive or flammable material is accidentally released, it.s highly likely to explode or burn before its vapor reaches the control room.
For this reason, only those substances whose toxicity limits are less than their lower limits of explosion and flammability will be considered for control room habitability here.
A list of these chemicals is presented in the Appendix.
An earlier list was published by the Committee on the Safety of Nuclear Installations.
The present list is by no means inciusive, but is representative of the substances that may be encountered.
Some of these substances have been reported to be stored or transported at or near nuclear power plants.
This information was obtained from applications of construction permits of nuclear power plants, as received by U. S. Nuclear Regulatory Commission, and from British Chemical Industry, Jones Bardelmeier and Company, Ltd.,
Natiorial Academy of Sciences, Navaz, and Simmons et al.
Following the suggestion of the Danish Ministry of the Environment (Steering Committee),
a number of the chemical agents reported to be potentially usable for warfare are also included in the list (Department of Defense, Hersh, Prentiss, Rothschild). Radioactive naterials, however, are excluded.
, 2147 335
It should be noted that any chemical which can generate airborne toxic products by chemical reactions or otherwise, should also be classified as a potential toxic substance.
Metallic sodium and potassium are good examples.
The so-called binary gas 3ystem of chemical warfare is another case in point.
However, the probability of coincidental release and reacting of two such chemicals in the same vicinity has, in the review to date, been so low that the event need not be considered here.
It may be desirable to compile and tabulate the inventory and application purpose (s) of each chemical substance that is stored and transported regularly at and/or near all the nuclear reactor instal-lations.
This is not attempted here, cs each nuclear power plant will be reviewed on a case-to-case basis.
3.2 Sources of Physical Data Included in Appendix are the physical properties that are necessary for the calculations of vapor concentration in the control room after a postulated accidental release, as discussed in Section 2.
These physical data were taken mainly from handbooks and references (Braker and Mossman, Dean, Dreisbach, Henderson and Haggard, Lange, Perry, Timmermans, Weast).
A few were obtained from chemical manufacturers and the Thermodynamic Research Center (Zwolinski).
4.
Acknowledgements The author is much indebted to the following individuais who contributed numerous valuable comments, corrections, and suggestions 2147 336
(in alphabetical order):
Kazimieras M. Campe (NRC), John T. Goll (NRC), Brian K. Grimes (NRC), Karl Hornyik (Oregon State University),
Ray Hosker (National Oceanic and Atmospheric Administration), Earl H.
Markee (NRC), Kenneth G. Murphy (NRC), and Ping K. Wan (Bechtel Power Corporation).
The assistance received from the various chemical manu-facturers and Therm > dynamic Research Center (Col k ge Station, TX) in the compi'ation of the physical properties of the chemicals is greatly appreciated.
5.
Bibliography R. B. Bird, W. E. Stewart, and E. N. Lightfoot, Transfer Phenomena, John Wiley and Sons, Inc., New York (1960).
R. E. Bolz and G. L. Tuve, Handbook of Tables for Applied Engineering Science, CRC Press, Cleveland, OH (1973).
W. Braker, and A. L. Mossman, Matheson Gas Data Book, 5th edition, The Matheson Company, Inc., E. Rutherford, NJ (1971).
British Chemical Industry Safety Council of the Chemical Industries Association Ltd.,
" Major Hazards.
Memorandum of Guidance on Extensions to Existing Chemical Plant Introducing a Major Hazard," (1975).
Available from the Chemical Industries Association Ltd., England.
V. T. Chow, Handbook of Applied Hydrology, McGraw - Hill Book Company, Inc., New York (1964).
Committee on Hazardous Materials, " Analysis of Risk in the Water Transpor-tation of Hazardous Materials," National Academy of Science (1976).
Available from National Research Council, Washington, D.C., 20418.
Committee on the Safety of Nuclear Installations, " Physical and Toxic Properties of Hazardous Chemicals Regularly Stored and Transported in the Vicinity of Nuclear Installations," (March 1976).
Available from Organization for Economic Cooperation and Development, Nuclear Energy Agency, Paris.
'6-
^
2147 337
C. V. Davis and K. E. Sorensen, Handbnok of Applied Hydraulics, McGraw -
Hill Book Company, New Ycrk (1969).
J. A. Dean, Lange's Handbook of Chemistry, McGraw - Hill Book Company, New York (1973).
Department of Defense, " Military Chemistry and Chemical Agents," Department of the Army Technical Manual TM3-215 (1963).
Available from Departments of the Army and the Air Force, Washington, D.C.
Directorate of Regulatory Standards, " Environmental Survey of Trans-portation of Radioactive Materials to and from Nuclear Power Plants,"
WASH-1238, U.S. Atomic Energy Commission (1972).
Available for inspection and copying for a fee at the NRC Public Document Room, 1717 H Street, N.W., Washington, D.C.
R. R. Dreisbach, Advances in Chemistry Series, Physical Properties of Chemical Compounds - I, II, III, American Chemical Society, Washington, DC (1961).
E. R. G. Eckert and R. M. Drake, Heat and Mass Transfer, McGraw - Hill Book Company, Inc., New York (1959).
D. FitzGerald, Trans. Am. Soc. Civil Engrs., 15, 581 (1886).
Available in public technical libraries.
S. Fritz and T. H. MacDonald, " Average Solar Radiation in the United States," Heat Ventilation, 4_6, 61-64 (1949).
Available from public technical libraries.
G. E. Harbeck, " Water-loss Investigations," Vol. I.
Lake Hefner Studies, Technical Report.
U. S. Geological Survey Paper 269 (1954).
Available from U.S. Geological Survey, Washington, D.C.
Y. Henderson and H. W. Haggard, Noxious Gases and the Principles of Respiration Influencing Their Actions, American Chemical Society Monograph Series Number 35, Reinhold Publishing Corp., New York (1943).
S. M. Hersh, Chemical and Biological Warfare, Doubleday and Company, Inc., Garden City, NY (1969T-W. F. Hilsmeier and F. A. Gifford, " Graphs for Estimating Atmospheric Dispersion," 0R0-545 (1962).
Available from National Technical Informa-tion Service, Springfield, VA 22161.
K. Hornyik, " Hazards to Nuclear Plants from Surface Traffic Accidents,"
Nucl. Tech., 25, 651 (1975).
Available from public technical libraries. 2147 338
K. Hornyik, " Hazards to Nuclear Plants from Off-Site Release of Toxic Vapors," Nucl. Tech., 28, 199 (1976).
Available from public technical libraries.
R. E. Horton, Eng. News-Rec. 78, 196 (1917).
Available from public technical libraries.
Jones Bardelmeier and Company, Ltd., "A Study of the Offshore Trade Flows and Traffic Patterns of Nine Hazardous Liquid Chemicals on the U.S. East and Gulf Coasts for Offshore Power System," OPS Report No. SA-1000-14A 36A, (1973).
Available from Jones Bardelmeier and Company, Ltd., Nassau, Bahamas.
G. E. Koberg, " Methods to Compute Long-Wave Radiation from the Atmosphere and Reflected Solar Radiation from a Water Surface," Geological Survey Professional Paper 272-F, (1964).
Available from U.S. Geological Survey, Washington, D.C.
M. A. Kohler, T. J. Nordenson, and D. R. Baker, " Evaporation Maps for the United States," U.S. Weather Bureau Technical Paper 37 (1959).
Available from Weather Bureau, Department of Commerce, Washington, D.C.
M. A. Kohler, T. J. Nordenson and W. E. Fox, " Evaporation for Pans and Lakes," U.S. Weather Bureau Research Paper 38 (May 1955).
Available from Weather Bureau, Department of Commerce, Washington, D.C.
N. A. Lange, Handbook of Chemistry, Handbook Publishers, Inc., Cleveland, OH (1946).
J. W. Langhaar, " Cooling Pond May Answer Your Water Cooling Problem,"
Chem. Eng. 60 (8), 194 (1953).
Available from public technical libraries.
W. Lerner, Statistical Abstract of the United States, Departnent of Commerce, Washington, DC (1974).
R. J. List, Smithsonian Meteorological Tables, Publication 4014, T.he Smit.hsonian Institution, Washington, DC (1966).
F. S. Merritt, Standard Handbook for Civil Engineering, McGraw - Hill Book Company, Inc., New York (1968).
A. F. Meyer, Trans. Am. Soc. Civil Engrs., 79, 1056 (1915).
Available from public technical libraries.
J. N. Murphy, M. E. Harris, D. Burgess, " Hazards of Marine Transportation of Liquid Chlorine," Department of the Interior, Bureau of Mines (1970).
Available for purchase at National Technical Information Service, Springfield, VA 22161. 2147 339
National Academy of Sciences, " System for Evaluation of the Hazardous of Bulk Water Transportation of Industrial Chemicals," AD-782 476 (1974).
Available for purchase at National Technical Information Service, Springfield, VA 22161.
M. Z. Navag, "The Carriage by Sea of Hazardous Cargoes Requiring Environ-mental Control," Trans. Institute of Marine Engineering, -83, 221-244 (1971).
Available from public technical libraries.
W. D. Patterson, J. L. Leporati, and M. J. Scarpa, "The Capacity of Cooling Ponds to Dissipate Heat," Proc. Am. Power Conference, 33, 446-456 (1971).
Available from public technical libraries.
R. H. Perry and C. H. Chilton, Chemical Engineers' Handbook, McGraw -Hill Book scmpany, New York (1973).
A. M. Prentiss, Chemicals in War, McGraw - Hill Book Company, Inc., New York (1937).
R. C. Reid and T. K. Sherwood, The Properties of Gases and Liquids, McGraw - Hill Book Company, New York (1958).
C. Rohwer, U.S. Department of Agriculture Technical Bulletin 271 (1931).
Available from Department of Agriculture, Washington, DC.
J. H. Rothschild, Tommorrow's Weapons, McGraw - Hill Book Company, New York (1964).
J. A. Simmons, R. C. Erdmann, and B. N. Naft, "The Risk of Catastrophic Spills of Toxic Chemicals," UCLA-ENG-7425 (1974).
Availabl9 from University of California, Los Angeles, CA.
L. E. Sissom and D. R. Pitts, Elements of Transport Phenoment McGraw
-Hill Book Company, New York (1972).
D. H. Slade, " Meteorology and Atomic Energy," TID-24190, U.S. Atomic Energy Commission, Washington, DC (1968).
Available for purchase at National Technical Information Service, Springfield, VA 22161.
Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants, LWR Edition, U.S. Nuclear Regulatory Commission, NUREG-75/087 (September 1975).
Available from National Technical Information Service, Springfield, VA 22161.
J. Timmermans, Physico-chemical Constants of Pure Organic Compounds, Elsevier Publishing Company, Inc., New York (1950).
D. B. Turner, " Workbook of Atmospheric Dispersion Estimates," Environmental Protection Agency, Research Triangle Park, NC (1970).
Available for purchase at National Technical Information Service, Springfield, VA 22161. 2147 340
A. P. Van Ulden, "On the Spreading of a Heavy Gas Released Near the Ground," First International Loss Prevention Symposium, Switzerland (1974).
Available from public technical libraries.
U.S. Atcmic Energy Commission, Regulatory Guide 1.78, " Assumptions for Evaluating the Habitability of a Nuclear Power Plant Control Room During a Postulated Hazardous Chemical Release" (1974).
Available from National Technical Information Service, Springfield, VA 22161.
L. C. Urquhart, Civil Engineering Handbook, McGraw - Hill Book Company, Inc., New York (1959).
R. C. Weast, Handbook of Chemistry and Physics, CRC Press, Cleveland, OH (1974).
G. R. Yanskey, E. H. Mark %, and A. P. Richter, "Climatography of the National Reactor Testing Station," 100-12048, National Reactor Testing Station, Idaho Falls, ID (1966).
Available from National Technical Information Service, Springfield, VA 22161.
Bruno J. Zwolinski, Thermodynamics Research Center, Department of Chemistry, Texas A&M University, College Station, TX 77843. 2147 34l
Appendix Physical Properties of Toxic Chemicals MW BP VD SG CP HV VP 0
Acetaldehyde 44.1 20.2 1.52
.783
.51 136.2 Acetic anhydride 102.1 140.0 3.52 1.057
.398 92.2 10.
Acetone 58.1 56.2 2.00
.791
.528 128.1 400.
.134 Acetone cyanohydrin 85.1 82.0 2.95
.932
.8 Acrolein 56.1 52.5 1.94
.841
.511 126.1 475.
Acrylonitrile 53.1 77.3 1.83
.806
.500 225.
Allyl chloriae 76.5 45.0 2.64
.938
.313 90.5 650.
Ammonia 17.0 - 33.4
.597
.674 1.1 327.4 Aniline 93.1 184.4 3.22 1.022
.521 103.7 1.5
.079 Arsine 77.9 - 62.5 2.69 1.604 51.2 Benzene 78.1 80.1 2.77 0.88 0.419
' ^ 3. 6 190.
0.077 Bromine 159.8 58.7 5.5 3.12
.107 44.9 380.
.109 Bromobenzylcyanide 196.0 242.
6.7 1.47 55.7 0.07 Butadiene 54.1 - 4.4 1.92
.621
.545 99.8 Butanol 74.1 117.5 2.55
.81
.563 141.3 18.
.092 Carbon dioxide 44.0 - 78.5 1.53
.468
.184 83.2 Carbon disulfide 76.1 46.5 2.64 1.293
.241 84.1 625.
.109 Carbon monoxide 28.0 -191.5
.968
.789
.515 51.6 Carbon tetrachloride 153.8 76.8 5.3 1.597
.201 47.3 211.
.081 Chlorine 70.9 - 34.1 2.49 1.570
.226 68.8 CNB 119.7 75.
4.1 1.14 CNC 129.6 60.
4.5 1.40 127.
CNS 144.5 60.
5.0 1.47 Cresol 108.1 198.
3.72 1.01
.55 102.9 1.
Cyanogen chloride 61.5 13.1 1.98 1.218 103.
.136 Diethylamine 73.1 55.5 2.53
.685
.564 96.4 425.
.109 Dimethylformamide 73.1 153.
2.51
.953 155.4 3.7 Diphenylchloroarsine 264.5 307.
9.15 1.387 56.6
.0016 Diphenylcyanoarsine 255.0 290.
8.75 1.32 79.3
.00005 Diphosgene 197.9 127.
6.9 1.66 10.3 Epichlorohydrin 92.5 116.1 3.21 1.181 40.
Ethyl acetate 88.1 77.2 3.04
.895
.459 102.
186.
.0935 Ethyl benzene 106.2 136.2 3.66
.867
.409 95.1 20.
.081 Ethyl chloride 64.5 12.3 2.22
.924
.368 90.6 Ethyldichloroarsine 174.9 156.
6.0 1.69 52.5
- 9. 5 Ethylene dichloride 99.0 83.5 3.35 1.253
.301 77.3 165.
2147 342 Appendix Physical Properties of Toxic Chemicals (continued)
Ethylene oxide 44.1 10.7 1.49
.897
.476 138.5 Ethyl ether 74.1 34.6 2.56
.708
.547 83.9
.0955 Fluo.ine 38.0 -188.3 1.70 1.503
.367 39.8 Formaldehyde (37% solution) 30.0 97.0 1.07 1.10 198.
Helium 4.0 -268.9
.137
.125
.86 4.84 Hexylene glycol 118.2 197.1 4.0
.923
.537 151.
.3 Hydrazine 32.0 113.5 1.1 1.008
.74 305.
30.
Hydrochloric acid 36.5 - 85.0 1.268 1.194
.90 103.1 Hydrogen cyanide 27.0 25.7
.947
.687
.627 247.0
.212 Hydrogen fluoride 20.0 19.5 1.27 1.003
.61 80.5 Hydrogen sulfide 34.1 - 60.8 1.19
.993
.478 131.
Isopropyl alcohol 60.1 80.3 2.07
.785
.78 159.4 106.
.106 Isopropylamine 59.1 32.4 2.03
.694
.385 110.
Lewisite 207.4 190.
7.2 1.89 58.
1.
Methanol 32.0 64.7 1.11
.792
.600 262.8 260.
.162 Methyldichloroarsine 160.9 133.
5.5 1.83 49.
10.
Mustard gas 159.1 227.8 5.4 1.27 94.
.4 Mustard-lewisite mixture 178.5 190.
6.0 1.66 58.
1.0 Nitric acid, conc.
(70% solution) 63.0 120.5 2.29 1.41
.615 114.9 10.
Nitrogen 28.0 -195.8
.97
.806
.474 47.5 Nitrogen mustard (HN-1) 170.1 85.
5.9 1.09 77.
.5 Nitrogen mustard (HN-2) 156.1 75.
5.4 1.15 78.8 1.16 Nitrogen mustard (HN-3) 204.5 137.
6.9 1.24 72.
.038 Pentaborane -9 63.2 58.4 2.2
.61
.571 121.8 400.
Perchloryl fluoride 102.5 - 46.7 3.73 2.003
.265 45.1 Phenol 94.1 181.9 3.24 1.058
.561 174.4 1.0 Phenyldichloroarsine 222.9 252.
7.75 1.65 67.
.113 Phosgene 98.9 8.2 3.4 1.419
.243 59.0
.117 Phosgene oxime 113.9 53.
4.0 Propionaldehyde 58.1 48.8 2.0
.806
.522 122.8 560.
Propylene oxide 58.1 34.3
- 2. 0
.831 Sarin 140.1 147.
4.86 1.089 84.9
- 5. 5 s
4 2147 543 Appendix Physical Properties of Toxic Chemicals (continued)
Soman 182.2 167.
6.33 1.022 78.5
.75 Styrene 104.1 145.2 3.6
.906
.416 101.7 20.
Sulfur dioxide 64.1
- 10.0 2.26 1.46
.361 92.8 Sulfuric acid 98.1 330.
3.4 1.83
.339 122.1 Tabun 162.3 246.
5.63 1.073 79.6
.1 Tetraethyl lead 323.5 200.
11.2 1.659 1.
Tetramethyl lead 267.3 110.
9.2 1.995 60.
Toluene 92.1 110.
3.14
.866
.421 98.6 55.
.0924 Trichlorcethylene 131.4 87.2 4.53 1.466
.223 62.3 140.
Vinyl acetate 86.1 72.
3.0
.932
.433 95.2 230.
Vinyl chloride 62.5
- 13.9 2.15
.920
.38 79.8 Xylene 106.2 140.0 3.66
.870
.400 96.0 20.
MW = Molecular weight (grams / mole)
BP = Normal boiling point (degrees centigrade)
VD = Relative vapor density (air = 1)
SG = Specific gravity (grams / cubic centimeter)
CP = Heat capacity of liquid (calories / gram-degree centigrade)
HV = Heat of vaporization of liquid (calories / gram)
VP = Vapor pressure at 40 degrees centigrade (millimeters of mercury)
D - Dif fusion coefficient (centimeter squares /second)
, 2147 344
U.S NUCLE AR REGUL ATORY COMMISSION 7
NUREG-0570 BIBLIOGRAPHIC DATA SHEET 4 TITLE AN D SUBTI TLE (Add Volume No.,t apprquoarel 2 / Leave o ao 41 Toxic Vapor Concentrations in the Control Room following a Postulated Accidental Release 3 HECIPIE NT S ACCESSION NO I AU T HO H IS )
- 5. D A T E H E POR T C O\\1PL F TE D l YEAR M ON TH James Wing May 1979 9 PE RF ORMING OHGANilA TION N A\\iE AND M AILING ADDHE SS (loctude lip Codel DATE REPOHT ISSUE D U.S. Nuclear Regulatory Commission
^ '-
vm" n^n Washington, D.C.
20555 6 ILetw tvanni 8 ! Leave b: anni 12 SPONSOHING OHG ANil ATION N AME AND M AIL NG ADDHE SS //ne'ude I,p Couel O I'POJE CT T ASA.nOHK UNIT NO U.S. Nuclear Regulatory Commission N/A Washington, D.C.
20555 n CONTR AcT NO N/A
- 13. TYPE OF REPOHT PE Rt 3D C ov E AE D #9ela..ve deel Technical Report 1975-1979 15 SUPPLE YEN TAH Y NOTE S 14 ILee n.r,* r N/A
- 16. ABS TH AC T (200.v oras or less)
The report presents an acceptable method for calculating the vapor concentrations in a j
control room as a function of time after a postulated accidental release.
Included are j
the mathematical formulas for computing the rates of vaporization ;nd evaporation of liquid spills, the vapor dispersion in air, and the control room air exchange. A list of toxic chemicals and their physical properties is also given.
i I
t 17 AE Y WOHDS AND DOCUYE NT AN AL YSIS i? DE SC +P To ks Toxic Vapor Concentrations Toxic Vapor Concentrations Control Room Habitability Chemical Spill Analysis D**D
- D'9'Y d
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J j
i 1/t' IDE N TIFIE HS OPE N E N DE l7 TE RYS Control Room Habitability 18 AV AIL ABILITY ST ATEME NT 13 SE ct Hi r < Clas.tr
.34.,
Unclassified Unlimited 20 sEcusiTY ctass err s vu,
.m N RC F ORNi 335 s 7 7 7; 2147 345
UNITED ST ATES f
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NUCLSAR REGULATORY COMMISSION tlp A$HING TON. D. C. 2%55 i
POST AGE AND F E E S P ABO US NUCLE A R RE GUL ATOR Y OF F ICI AL BUSINESS C OM u s sSB ON PE N ALT Y F OR PRIV AT E USE, $ 300 U S MAJ's t
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