ML20116A518
| ML20116A518 | |
| Person / Time | |
|---|---|
| Site: | 05200003 |
| Issue date: | 07/31/1995 |
| From: | Powers D SANDIA NATIONAL LABORATORIES |
| To: | NRC |
| Shared Package | |
| ML20116A512 | List: |
| References | |
| NUDOCS 9607260133 | |
| Download: ML20116A518 (42) | |
Text
, _ _ _ _ - _ _--_---_-_- _-- - - --- ---- - - - - - - - - - - - - - -
l TECIINICAL EVALUATION REPORT 1 I
I l MONTE CARLO UNCERTAINTY ANALYSIS OF AEROSOL BEHAVIOR IN THE l AP600 REACTOR CONTAINMENT PART 2: FIXED BOUNDARY CONDITIONS l AND A KNOWN SOURCE OF NOhTADIOACTIVE AEROSOL I
I I
I D. A. Powers Sandia National Laboratories Albuquerque, NM
~
I l July 1995 I
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l ABSTRACT A Monte Carlo uncertainty analysis of aerosol behavior in the containment of the AP600 reactor during a hypothetical 3BE accident is described. For this uncertainty analysis, l boundary conditions of pressure, temperature, gas composition, steam condensation rates and
! heat removal rates were treated as certain. Also, the raa of nonradioactive aerosol generation during the period of in-vessel release of radionuclides (1800 to 6480 seconds) was fixed at 56.12728 g/s. Uncertainties in aerosol processes and aerosol properties were l considered in the analyses. Uncertainty distributions for the decontamination factors and i decontamination coefficients are compared to similar distributions obtained in a previous uncertainty analysis which included uncertainty in the nonradioactive source term. It is found that higher decontamination factors are obtained with the large, known nonradioactive source term. The effective decontamination coefficient during the period 6480 to 13680 seconds is most affected by the nonradioactive source. Most of the aerosol mass removal from the containment atmosphere takes place in this time interval. The median effective decentamination coefficient calculated for this period is onite similar to the time-averaged value of the decontamination coefficient obtained with ti , NAUAHYGROS computer code.
Time-averaged values obtained with the NAUAHYGROS code for later times lie above the 90th percentile of uncertainty distributions calculated for the effective decontamination l coefficients. The discrepancies between results of the uncertainty analyses and results ;
obtained with the NAUAHYGROS code at late times affect removal of only the last 10 percent of the aerosol injected into the AP600 containment during the hypothesized accident. It is concluded that the Monte Carlo uncertainty analyses for aerosol behavior and .
NAUAHYGROS analyses of aerosol behavior will yield best-estimate results in substantial !
agreement provided that similar boundary conditions and source terms are assumed.
Conservative values of the decontamination coefficients that would provipe allowances for uncertainties in aerosol properties and processes are about a factor of'e'6 sinaller than best- :
estimate values. These conservative values of the effective decontamination coefficient vary !
over a range of 0.265 to 0.435 hr'I during the interval from 0 to 86450 seconds after the !
start of radionuclide release to the AP600 containment atmosphere. Highest values of the j effective decontamination coefficient are achieved shortly after completion of in-vessel release I of radionuclides to the containment atmosphere when both gravitational settling and I diffusiophoresis are important, natural aerosol removal processes. At later times, the effective decontamination coefficient varies toward lower values according to the magnitude of forces driving diffusiophoretic deposition of aerosols.
I i
i/ii l
[ 1 TABLE OF CONTENTS
[ i ABSTRACT ............................................
[ I. INTRODUCTION ..................................... 1
- 11. RESULTS .......................................... 3
- m. CONCouSiONS ...................................... iv
[ IV. REFERENCES ....................................... 19 APPENDIX A. UNCERTAINTY DISTRIBUTIONS FOR THE DECONTAMINATION FACTORS AND DECONTAMINATION COEFFICIENTS . . . . . . . . . . . . . . . . A-1
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F 111 1
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i LIST OF FIGURES
[
j Figure Page
! 1 Comparison of Decontamination Coefficients Found in the Monte I Carlo Analyses With Fixed Boundary Conditions and Uncertain f
l.
Source Terms to Results Obtained with the NAUAHYGROS Code . . . . . . . . 2 I I
2 Predicted Iodine Concentration in the Containment Atmosphere as a [
j Function of Time for the 3BE Accident at the AP600 Reactor . . . . . . . . . . . 8 !
l a
3 Predicated Cesium Concentration in the Containment Atmosphere as a
. Function of Time for the 3BE Accident at the AP600 Reactor . . . . . . . . . . . 9 4 Predicted Tellurium Concentration in the Containment Atmosphere as a
, Function of Time for the 3BE Accident at the AP600 Reactor . . . . . . . . . . . 10 I ;
5 Predicted Barium Concentration in the Containment Atmosphere as a i
- Function of Time for the 3BE Accident at the AP600 Reactor . . . . . . . . . . . 11 !
t 4
6 Predicted Cerium Concentration in the Containment Atmosphere as a !
l Function of Time for the 3BE Accident at the AP600 Reactor . . . . . . . . . . . 12 i
i j 7 Predicted Ruthenium Concentration in the Containment Atmosphere as a !
- Function of Time for the 3BE Accident at the AP600 Reactor . . . . . . . . . . . 13 I i ;
i
, 8 Predicted Lanthanum Concentration in the Containment Atmosphere as a i Function of Time for the 3BE Accident at the AP600 Reactor . . . . . . . . . . . 14 )
- i i 9 Comparison of Decontamination Coefficients Found in the Monte Carlo
- Uncertainty Analysis with Fixed Boundary Conditions and Fixed I '
Nonradioactive Aerosol Source Term to Results Obtained With the NA U AH YG ROS Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 l
! l
- l i
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! iv
LIST OF TABLES Table P_ age 1 Features of the Uncertainty Distributions for Decontamination Factors Due to Natural Aerosol Processes . . . . . . . . . . . . . . . . . . . . . . . 4 2 Features of the Uncertainty Distributions for the Decontamination Coefficients Due to Natural Aerosol Processes .................... 6 3 Comparison of Uncertainty Distributions for the Decontamination Coefficients to the Time-Averaged Values Calculated with the NAUAHYGROS Computer Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 4 Comparison of Effective Decontamination Coefficients From Various A nalyses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 A-1 Uncertainty Distributions for the Gap Release Decontamination Factor at 1800 Seconds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-2 A-2 Uncertainty Distribution for the Gap Release Decontamination Factor at 64 80 Second s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-3 A-3 Uncertainty Distribution for the Gap Release Decontamination Factor at 13680 Second s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-4 A-4 Uncertainty Distribution for the Gap Release Decontamination Factor at 49680 Seconds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-5 A-5 Uncertainty Distribution for th. Gap Release Decontamination Factor at 86450 Seconds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-6 A-6 Uncertainty Distribution for the In-Vessel Release Decontamination Factor at 64 80 Seconds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-7 A-7 Uncertainty Distribution for the In-Vessel Release Decontamination Factor at 13680 Seconds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-8 A-8 Uncertainty Distribution for the In-Vessel Release Decontamination Factor
( at 49680 Second s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-9 A-9 Uncertainty Distribution for the In-Vestel Release Decontamination Factor at 86450 Seconds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-10 A-10 Uncertainty Distribution for the Effective Decontamination Coefficient During the Interval 0 to 1800 Seconds .........................A-11 r
V
i l
LIST OF TABLES (CONCLUDED) !
j Table P_ age A-11 Uncertainty Distribution for the Effective Decontamination Coefficient for Gap Release Material During the Interval 1800 to 6480 Seconds ....... A-12 A-12 Uncertainty Distribution for the Effective Decontamination Coefficient for In-Vessel Release Material During the Interval 1800 to 6480 Seconds ...... A-13 A-13 Uncertainty Distribution for the Effective Decontamination Coefficient During the Interval 6480 to 13680 Seconds ...................... A-14 A-14 Uncertainty Distribution for the Effective Decontamination Coefficient During the Interval 13680 to 49680 Seconds . . . . . . . . . . . . . . . . . . . . . . A-15 A-15 Uncertainty Distribution for the Effective Decontamination Coefficient l During the Interval 49680 to 86450 Seconds . . . . . . . . . . . . . . . . . . . . . . A-16 '
A-16 Uncertainty Distribution for the Time-Averaged Decontamination Coefficient for 0 to 1800 Seconds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-17 vi
[
I. INTRODUCTION In a previous report [1], results of a Monte Carlo uncertainty analysis of aerosol behavior in the containment of the AP600 reactor under the conditions of a specific accident (3BE [2])
[ were reported. Uncertainty distributions for the decontamination factors at selected times (1800, 6400,13680, 49680, and 86450 seconds) and effective decontamination coefficients produced by natural aerosol processes were developed in this previous work. These
[ uncertainty distributions considered uncertainties in a variety of physical phenomena and uncertainties in the release of nonradioactive aerosol to the containment, but kept fixed essential boundary conditions:
- containment pressure,
- containment atmosphere temperature,
- mole fraction steam in the containment atmosphere,
- rate of steam condensation from the atmosphere, and a rate of heat removal from the containment atmosphere.
Uncertainty distributions for the effective decontamination coefficients were centered around values significantly less than either the instantaneous or the time-averaged " point" values calculated with the NAUAHYGROS code [2]. A comparison of the point values and the results of the Monte Carlo uncertainty analysis is shown in Figure 1. The solid line in this figure was obtained by linearly interpolating among the instantaneous values calculated with
{ the NAUAHYGROS computer code. Time-averaged values of these instantaneous values are shown as open symbols in Figure 1. Median values of the effective decontamination coefficients found in the Monte Carlo uncertainty analysis are indicated by the X symbol.
Bars on these symbols denote the 80 percent confidence intervals. The point values are shown to fall outside the 80 percent confidence intervals obtained in the uncertainty analysis.
It was hypothesized in Reference 1 that the higher values of the decontamination coefficients obtained with the NAUAHYGROS computer code might be the result of a large, assumed
( source of nonradioactive aerosol during the in-vessel release phase (1800 to 6480 seconds) of the accident. For the NAUAHYGROS code calculations, it was assumed that the nonradioactive aerosol mass would be about 3.62 times the mass of radioactive aerosol. In
[ the Monte Carlo uncertainty analysis, the nonradioactive aerosol mass was taken to be uncertain. It was assumed that this nonradioactive aerosol mass was uniformly distributed over the interval of 0.5 to 2.0 times the mass of radioactive aerosol. There was, then, in all
( the calculations for the Monte Carlo uncertainty analysis less total aerosol mass than in the NAUAHYGROS calculations. Particles would not be able to grow as much in most of the Monte Carlo uncertainty analysis calculations as in the NAUAHYGROS calculation despite
[ the fact that additional agglomeration mechanisms were included in the Monte Carlo calculations.
The calculations described in this report were undertaken to see if the additional nonradioactive aerosol mass was indeed responsible for the high values of the decontamination coefficients due to natural aerosol processes calculated with the NAUAHYGROS code [2]. The Monte Carlo uncertainty analysis was done exactly as l
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Figure 1. Comparison of Decontamination Coefficients Found in the Monte Carlo Uncertainty Analyses With Fixed Boundary Conditions and Uncertain Source Terms [1] to Results Obtained With the NAUAHYGROS code [2]. The solid line indicates instantaneous values calculated with NAUAHYGROS. Open symbols are the time averages of these instantaneous values. The X symbol and bars indicate the 90 percent confidence intervals for results of the uncertainty l analysis.
described in the previous work except the nonradioactive aerosol mass over the interval from 0 to 1800 seconds was taken to be zero and over the interval from 1800 to 6480 seconds was taken to be 56.12728 g/s as it was in the analyses done with the NAUAHYGROS computer code.
The elemental releases of rr.dionuclides in the Monte Carlo uncertainty analysis were taken to be the same as those assumed for the analyses with the NAUAHYGROS code. Specific chemical forms of the radionuclides were hypothesized for the NAUAHYGROS calculations.
Chemical forms of the radionuclides in the AP600 reactor containment under the conditions of the specific accident were treated as uncertain in the Monte Carlo uncertainty analysis.
The additional aerosol mass created because radionuclides react with gaseous species was then ;
varied in the Monte Carlo uncertainty analyses.
Uncertainties due to physical properties of the aerosols and due to uncertainties in aerosol processes were treated in exactly the same way as was described in Reference 1.
II. RESULTS R:sults of the calculations are uncertainty distributions for the decontamination factors at 1:. 00, 6480,13680, 49680, and 86450 seconds and effective decontamination coefficients for (ne time intervals 0-1800,1800-6480, 648013680,13680-49680, and 49680-86450 seconds.
These uncertainty distributions were calculated as described in Reference 1. The uncertainty distributions are formulated as ranges of values of the decontamination factors or l
decontamination coefficients that to either the 90 percent or the 50 percent confidence level correspond to quantiles of the uncertainty distribution between 5 and 90 percent at 5 percent steps.
The detailed uncertainty distributions are collected in Appendix A of this report. In the remainder of the discussion of results, only selected values of the distribution are considered:
, the median or 50 percentile values (at 50 percent confidence) which are called the "best estimate values" here, the 90 percentile values (at 90 percent confidence) which are called " reasonable upper bound values" here, and the 10 percentile values (at 90 percent confidence) which are called " reasonable low bound values" here.
Mean values are also provided here though means of the uncertainty distributions developed here have no particular statistical significance.
The features of the uncertainty distributions for decontamination factors for materials released to the containment during the gap release phase and the in-vessel release phase of the 3BE reactor accident are shown in Table 1. The distributions found for the decontamination factors are essentially the same as those found in the previous work [1] at 1800 and at 3
l l
l l
Table 1. Features of the Uncertainty Distributions for Decontamination Factors Due to Natural Aerosol Processes Decontamination Factor Time Median Upper Bound IAwer Bound (s) (50 percentile *) (90 percentile **) (10 percentile **) Mean +
GAP RELEASE 1800 1.205 to 1.206 1.220 to 1.227 1.184 to 1.185 1.205 6480 2.095 to 2.102 2.209 to 2.267 1.921 to 1.973 2.094 13680 7.038 to 7.353 11.31 to 12.66 4.722 to 5.251 7.905 49680 134.7 to 138.4 222.8 to 265.4 66.04 to 79.87 148.7 86450 2903 to 3090 5524 to 6654 1099 to 1548 3409 IN-VESSEL RELEASE 6480 1.263 to 1.265 1.286 to 1.297 1.225 to 1.237 1.263 13680 4.228 to 4.411 6.861 to 7.476 2.964 to 3.160 4.759 49680 79.54 to 83.82 133.6 to 156.4 41.67 to 47.76 89.25 86450 1761 to 1878 3236 to 3844 694.9 to 975.4 2032
,,At 50 percent confidence.
At 90 percent confidence.
+The mean has no particular statistical significance.
l l
4
6480 seconds. Decontamination factors at later times are found to be much larger than was found in the previous uncertainty analysis. The additional aerosol mass from nonradioactive sources accentuates aerosol particle growth and consequently aerosol removal from the containment atmosphere particularly by gravitational settling.
The features of the uncertainty distributions for the effective decontamination coefficients are listed in Table 2. In examining these results, recognize that the formulation adopted here for the effective decontamination coefficient yields distinct values for the materials released during the gap release phase of an accident and for materials released during the in-vessel release phase for the time interval 1800 to 6480 seconds. Also note that the effective decontamination coefficient formulation includes the effect of the aerosol source which contaminates the atmosphere while other processes decontaminate the containment atmosphere. Consequently, the effective decontamination coefficients for gap release material over the time interval 0 to 1800 seconds and for in-vessel release material over the time interval 1800 to 6480 seconds are expected to be lower than instantaneous values of decontamination coefficients calculated in treatments that address the aerosol source and the aerosol removal processes separately.
The median decontamination coefficients calculated here assuming both fixed (not uncertain) boundary conditions and a fixed source of nonradioactive aerosols can be compared to median decontamination coefficients calculated previously assuming the same, fixed boundary conditions and an uncertain source of nonradioactive aerosol:
1 1
Median (hr-I) fixed Median (hr-l) fixed boundary boundary conditions and conditions and uncenain Time Interval (s) fixed nonrad source nonrad source 0-1800 0.374 0.001 0.372 0.001 1800 - 6480 0.426 0.002 0.420 0.002 i (gap release)
I800 - 6480 0.I80 0.001 0.178 0.001 (in-vessel release) 6480 - 13680 0.613 0.010 0.449 0.006 13680 - 49680 0.291 0.002 0.260 0.003 49680 - 86450 0.300 i 0.001 0.298 0.001 The median decontamination coefficients are sensibly identical for the time intervals 0 to 1800,1800 to 6480, and 49680 to 86450 seconds. The median decontamination coefficients calculated here with a large, fixed source of nonradioactive aerosol are substantially larger for the time interval 6480 to 13680 seconds and somewhat larger for the interval 13680 to 49680 seconds. Again, the additional aerosol mass produced by the large nonradioactive source term during in-vessel release (1800 to 6480 seconds) accentuates particle growth and removal from the containment atmosphere. With time and continued decontamination of the atmosphere once the nonradioactive source has stopped, the effect disappears.
5
Table 2. Features of the Uncertainty Distributions for the Decontamination Coefficients Due to Natural Aerosol Processes Ae, Effective Decontamination Coefficient (hr-3)
Tim Interval Median Upper Bound Ixwer Bound *
- (50 percentile") (90 percentile **) (10 percentile *)
(s) Mean+
0-1800 0.373 to 0.375 0.398 to 0.410 0.337 to 0.349 0.373 1800-6480 0.424 to 0.427 0.456 to 0.472 0.374 to 0.389 0.424 (gap release) 1800-6400 0.180 to 0.181 0.193 to 0.200 0.155 to 0.164 0.179 (in-vessel release) 6480-13680 0.603 to 0.623 0.850 to 0.887 0.435 to 0.461 0.639 13680-49680 0.289 to 0.292 0.304 to 0.310 0.264 to 0.272 0.289 49680-86450 0.299 to 0.301 0.324 to 0.336 0.268 to 0.278 0.301
,,At 50 percent confidence.
At 90 percent confidence.
+The mean has no particular statistical significance.
6
The decontamination coef0cients calculated here can be used to estimate the concentrations of various radionuclides in the AP600 reactor containment atmosphere during the 3BE accident.
[ These estimates are shown in Figures 2 through 8. In each of the figures, the best estimate, which is assumed here to be the median or 50 percentile estimate, is shown as a solid line.
Reasonable upper and lower bound concentrations are considered here to be indicated by the
{
90 and 10 percentile estimates which are shown as dashed lines in the figures.
The effective decontamination. coefficients calculated here are compared to those calcuhted with the NAUAHYGROS model [2] in Figure 9. In this figure the decontamination coefficients calculated here are indicated by filled symbols. Bars on the filled symbe .,
indicate the 80 percent confidence interval. The uncertainty distributions of the decontamination coefficients calculated here are compared in Table 3 to time-averaged values obtained from the NAUAHYGROS calculations. Note that the effective decontamination
[ coefficient calculated for the 0 to 1800 second interval is not directly comparable to time-averaged values of the decontamination coefficient calculated with the NAUAHYGROS code.
A separate set of Monte Carlo analyses were done to compute time-average <! decontamination
[ coefficients that can be compared directly to values obtained with the NAUAHYGROS code.
Results of these calculations for 0 to 1800 seconds are:
( 1 (median) = 0.530 0.005 hr-I 1 (upper bound) = 0.584 0.010 hr-I
[
A (lower bound) = 0.488 0.007 hr-I
[ A (mean) = 0.534 hr-I These values may be compared to the time-averaged value for the 0 to 1800 second interval
[ obtained with the NAUAHYGROS code, A = 0.564 0.007 hr-I. It is evident that the model used for the Monte Carlo uncertainty analysis treats aerosol deposition early in an accident when diffusiophoresis is the dominant deposition process in a manner somewhat
[- similar to the treatment in the NAUAHYGROS code.
During the interval 6480 to 13680 seconds when most of the mass removal takes place, the
[ time-averaged value from the NAUAHYGROS calculation is quite similar to the median of the uncertainty distribution calculated here. The " point" value calculated from results
{ obtained with the NAUAHYGROS code falls in the range characteristic of the 60th percentile of the uncertainty distribution. It is apparent, then, that for large aerosol particles that are removed predominantly by gravitational settling, the NAUAHYGROS computer code and the
{ medel used for the uncertainty analysis behave similarly. Most of the aerosol mass injected into the AP600 containment is deposited during the periods for which NAUAHYGROS and the uncertainty analyses yield similar results.
[
The cause of the high bias of point values of the decontamination factors at times after 13680 seconds has not been identified. Instantaneous values of the decontamination
[ coefficient calculated for late times with 'he NAUAHYGROS computer code do not seem to follow closely the variations in the driving forces for particle deposition by phoretic r
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Figure 6. Predicted Cerium Concentration in the Containment Atmosphere as a Function of Time for the 3BE Accident at the AP600 Reactor. The solid line is the median estimate. The upper and lower dashed lines are the 90 and 10 percentile estimates.
W RUTHENIUM m
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@ 100 1000 10000 100000 TIME (SECONOS) i Figure 7. Predicted Ruthenium Concentration in the Containment Atmosphere as a Function of Time for the 3BE Accident at the AP600 Reactor. The solid line is the median estimate. The upper and lower dashed lines are the 90 and 10 percentile l
i estimates.
l l
6
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l W LANTHANUM m
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(h i i i i iiiit i e i i ieinn i i i i i su i
@ 100 1000 10000 100000 TIME (SECONDS)
Figure 8. Predicted lanthanum Concentration in the Containment Atmosphere as a Function of Time for the 3BE Accident at the AP600 Reactor. The solid line is the median estimate. The upper and lower dashed lines are the 90 and 10 percentile estimates.
_ 4 m 1.00 . . . . ..... . . . . . . . . . . i . . . . . . . .
y - --
UNCERTAINTY ANALYS$S-# ART 2 -
t _
_r :: EFFECTIVE VALUIES v -
g O.75 -
e TIME AVERAGED '/ALUE
- j i U _ l .
H h'" ,
u_ -
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9
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- E _ INSTANTAN OUS VALUES _
> H -
O TIME AVER GED VALUES -
z - -
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- + ,.s .
TIME (SE ONDS)
Figure 9. Comparison of Decontamination Coefficients Found in the Mo te Carlo Un(prtainty Analysis With Fixed Boundary Conditions and Fixed Nonradioactive Acrosol Source Term to Results Obtained With the NAUAHYGROS Code [2].
Results obtained in the calculations described in this report ar indicated by filled symbols and bars. Other symbols are defined in Figure 1. h I
go M /-&
Jhv
w -, - _- - ,-, - , - , , - ,
Table 3. Comparison of Uncertainty Distributions for the Decontamination Coefficients to Time-Averaged Values Calculated With the NAUAHYGROS Computer Code Time Averaged + Upper Bound (a) Median (D) Lower Bound (a)
Time Interval At (hr-l) A, (hr-I) A,(hr-I) A,(hr-I)
(s) 0.5645 0.0074 0.404 0.006 0.374 0.001 0.343 0.006 0-1800*
,M52 [dd8 1800-6480 0.5410 i 0.0091 0.464 i 0.008 0.426 i 0.002 6480-13680 0.6849 i 0.0152 0.869 0.019 0.613 i 0.010 0.448 t 0.013 g
13680-49680 0.5392 i 0.0082 0.307 i 0.003 0.291 i 0.002 0.268 i 0.004 49680-86450 0.4816 i 0.0032 0.330 i 0.006 0.300 i 0.001 0.273 i 0.005 >
Source operational during this period so the values of the effective decontamination coefficient, A e, are expected to be lower than the time average of instantaneous values, At -
+From NAUAHYGROS results [1,2]; uncertainty range is the square root of the variance about the mean.
(a)90 percent confidence interval.
(b)50 percent confidence interval.
processes. Decontamination coefficients calculated for these late times with the model used for the Monte Carlo uncertainty analysis do vary with these driving forces. It appears, then, that the larger decontamination coefficients calculated with NAUAHYGROS are the results of some differences in the treatments of processes other than diffusiophoresis and thermophoresis. The most likely candidates are differences ir. tne treatments of aerosol particle growth processes at low particle concentrations. The net effect of these differences is that the NAUAHYGROS code predicts somewhat faster re noval of the last 10 percent of the aerosol mass injected into the containment than was found ;n the uncertainty analyses. Still, the uncertainty analyses indicate that about 99 percent of the aerosol has been removed from the atmosphere by 49680 seconds and more than 99.9 percent has been removed by 86450 seconds.
III. CONCLUSIONS A Monte Carlo uncertainty analysis of aerosol behavior in the containment of the AP600 reactor during a hypothetical 3BE accident has been conducted assuming fixed (not uncertain) boundary conditions and a large, known source of nonradioactive aerosol as well as the radioactive aerosol releases specified in the Revised Severe Accident Source Term [3]. This uncertainty analysis supplements a previous analysis [1] based on similar boundary conditions and radioactive aerosol releases that treated the nonradioactive aerosol source term as uncertain. Both analyses supplement a preliminary analysis [4] that used uncertain, generic light water reactor accident boundary conditions.
Effective decontamination coefficients calculated in these three uncertainty analyses are compared in Table 4. Also shown in this table are the time-averaged & contamination coefficients calculated for the 3BE accident at AP600 with the NAUAHYGROS code.
Comparison of the results of the previous analysis [1] and results of the preliminary analysis
[4] shows that the unique thermal hydraulic boundary conditions predicted [2] to exist during an AP600 accident enhance aerosol removal from the containment atmosphere by natural processes. The enhanced rates of aerosol removal found in the previous uncertainty analysis
[1] bre, however, not as large as predicted with the NAUAHYGROS code. Including a large nonradioactive aerosol source term in the uncertainty analysis reported here yields best estimate (median) decontamination coefficients similar to point values calculated with the NAUAHYGROS code except at late times when most of the aerosol has been removed from the containment atmosphere.
These comparisons of results suggest that reasonable agreement on best-estimate decontamination coefficients can be obtained if agreements are reached on:
o boundary corditions (pressure, temperature, gas composition, steam condensation rates and heat removal rates) and o
sources of nonradioactive aerosols to the containment atmosphere.
Further exploration of the treatments of aerosol properties and processes could improve the agreement among calculated values of the decontamination coefficients. Such efforts are, 17
, c r, c-- . ,-- r- r- e- r- e- _
m m e- . c- ,- c-Table 4. Comparison of Effective Decontamination Coefficients From Various Analyses Median, A, (50), and 10 to 90 Percentile Range From Time-Averaged Decontamination Preliminary Analysis Previous Analysis [1]** Coefficient from Time Interval (seconds) [4]* (hr-1) (hr-l) This Work + (hr-I) NAUAHYGROS (hr-I) 0 - 1800 0.034 (0.024 to 0.043) 0.372 (0.336 to 0.413) 0.374 (0.337 to 0.410) 0.564 0.007
= 1800 - 6480 0.073 (0.054 to 0.102) . 0.420 (0.368 to 0.479) '0.425 (0.374 to 0.472) ; 0.541 i 0.009 6480 - 13680 0.170 (0.076 to 0.418) 0.449 (0.371 to 0.604) (. - 0.613 (0.435 to 0.887) (0.685i0.015 13680 - 49680 0.091 (0.085 to 0.101) 0.260 (0.225 to 0.290) 0.290 (0.264 to 0.310) 0.539 i 0.008 4 % 80 - 86450 0.038 (0.027 to 0.052) 0.298 (0.267 to 0.340) 0.300 (0.268 to 0.336) 0.482 i 0.003
- Uncertain generic LWR boundary conditions and geometry; uncertain nonradioactive source term.
AP600 geometry, 3BE boundary conditions, and uncertain nonradioactive source term.
+ AP600 geometry, 3BE boundary conditions, and known nonradioactive source term.
_.......a. _ . . . . . . . - - - - - . - - - -
however, less important since most of the aerosol mass is removed during the accident period for which the NAUAHYGROS calculations and the Monte Carlo uncertainty analyses yield similar best-estimate values.
There are uncertainties in aerosol properties and aerosol processes that do affect predictions of decontamination coefficients associated with natural aerosol processes in the AP600 containngt atgosphere. Reasonable lower bound values of the decontamination coefficients are about mayas large as the best-estimate values based on the current understanding of aerosol properties and processes in reactor accidents. The discrepancy between lower bound I
(10 percentile) and best-estimate (50 percentile) values of the effective decontamination coefficients can be narrowed only when there is a better understanding of aerosol processes I (for example, collision factors and turbulent processes) and aerosol properties (for example, shape factors, accommodation coefficients, and slip correction factors) during accidents hypothesized to occur in the AP600 reactor.
IV. REFERENCES
- 1. D. A. Powers, Monte Carlo Uncertainty Analysis of Aerosol Behavior in the AP600 Reactor Containment Under Conditions of a Specific Design-Basis Accident, Sandia National Laboratories, Albuquerque, NM, June 1995.
- 2. I2tter from N. J. Liparuto to T. R. Quay, entitled "Information Requested by RAI ,7.J 1 Regarding Input Parameters for the Calculation of Aerosol Removal Coefficients," NTD-1 NRC-95-4430, DCP/NRC0302 Docket No.: STN-52-003, April 7,1995.
- 3. L. Soffer et al., Accident Source Terms for Light-Water Nuclear Power Plants, NUREG-I 1465 U.S. Nuclear Regulatory Commission, Washington, D.C.,1995.
j
- 4. D. A. Powers, K. E. Washington, S. B. Burson, and J. L Sprung, A Simplified Model I of Aerosol Removal by Natural Processes in Reactor Containments, NUREG/CR-6189,
, SAND 94-0407, Sandia National Laboratories, Albuquerque, NM, September 1995.
I I
[
[
L 19 e
I l
l APPENDIX A. DETAILED UNCERTAINTY DISTRIBUTIONS The detailed uncertainty distributions for the decontamination factors and the effective decontamination coefficients calculated for this report are listed in Tables A-1 to A-15.
Table A-16 is a tabulation of the uncertainty distribution for the time-averaged value of the decontamination coefficient for the period 0 to 1800 seconds. These distributions were developed from the results of the Monte Carlo sampling using nonparametric order statistics.
The distributions are presented as the range of values characteristic of specified percentiles of a cumulative distribution. Percentiles are specified at 5 percent intervals from 5 to 95 percent. Ranges of values characteristic of these percentiles must be specified because j only a finite number of samples (typically 180) were collected in the Monte Carlo uncertainty ;
analysis. The ranges can be narrowed by further sampling, but they narrow with increasing values of the square root of the number of samples taken. In general, ranges found in this work are narrow enough that they do not complicate the interpretation of the results.
1 The ranges are tabulated at two confidence levels-90 percent and 50 percent. At the 90 percent confidence level there is a 90 percent confidence that the true value of the uncertain parameter indicative of the specified percentile of the cumulative distribution lies 1 within the quoted range and a 10 percent probability that it is at either a higher or lower )
value. The narrower ranges at the 50 percent confidence level can be similarly interpreted.
Mean values of the sample sets are also listed in the tables. These mean values do not have any particular statistical significance for the uncertainty distributions found in this work. It is '
usually found that the mean is quite near the median (50 percentile) of a distribution.
\
l 1
1 1
A-1
7 > mumm - mums mumm uma mums ummm m'w Table A-1. Uncertainty Distribution for the Gap Release Decontamination Factor at 1800 Seconds Values of the Decontamination Factor Percentile Characteristic of the Indicated Percentile at a Confidence Level, C, of
, C = 90% C = 50%
5 1.181 to 1.185 1.181 to 1.183 10 1.184 to 1.191 1.187 to 1.189 15 1.188 to 1.194 1.190 to 1.192 20 1.192 to 1.197 1.192 to 1.195 25 1.194 to 1.199 1.196 to 1.198 30 1.197 to 1.201 1.198 to 1.199 )
35 1.199 to 1.203 1.199 to 1.201
> 40 1.200 to 1.205 1.201 to 1.203 45 1.202 to 1.206 1.203 to 1.205 50 1.204 to 1.207 1.205 to 1.206 55 1.205 to 1.208 1.206 to 1.207 60 1.207 to 1.209 1.207 to 1.208 65 1.207 to 1.212 1.208 to 1.210 70 1.209 to 1.215 1.210 to 1.213 j 75 1.211 to 1.216 1.213 to 1.215 )
80 1.215 to 1.219 1.215 to 1.218 85 1.217 to 1.224 1.218 to 1.220 90 1.220 to 1.227 1.223 to 1.226 95 1.226 to 1.230 1.228 to 1.229 Mean = 1.205 l
w ==== - ummus unusu - umum ummu Table A-2. Uncertainty Distribution for the Gap Release Decontamination Factor at 6480 Seconds Values of the Decontamination Factor Percentile Characteristic of the Indicated Percentile at a Confidence Level, C, of C = 90% C = 50%
5 1.904 to 1.939 1.908 to 1.918 10 1.921 to 1.973 1.941 to 1.959 l
15 1.955 to 2.007 1.969 to 1.990 20 1.982 to 2.023 2.003 to 2.015 25 2.001 to 2.046 2.018 to 2.034 30 2.022 to 2.062 2.037 to 2.056 35 2.042 to 2.073 2.056 to 2.063 40 2.059 to 2.087 2.063 to 2.077 6 45 2.065 to 2.099 2.077 to 2.096 50 2.083 to 2.106 2.095 to 2.102 55 2.096 to 2.I14 2.102 to 2.108 60 2.103 to 2.128 2.108 to 2.117 65 2.112 to 2.144 2.117 to 2.137 70 2.123 to 2.165 2.138 to 2.150 75 2.142 to 2.180 2.152 to 2.171 80 2.164 to 2.203 2.174 to 2.I89 85 2.I81 to 2.236 2.192 to 2.210 90 2.209 to 2.267 2.229 to 2.260 95 2.262 to 2.292 2.268 to 2.285 Mean = 2.094 I
Table A-3. Uncertainty Di,stribution for the Gap Release Decontamination Factor at 13680 Seconds Values of the Decontamination Factor Percentile Characteristic of the Indicated Percentile at a Confidence Level, C, of -
C = 90% C = 50%
5 4.423 to 4.840 4.606 to 4.712 10 4.722 to 5.251 4.871 to 5.085 15 5.041 to 5.474 5.223 to 5.360 20 5.312 to 5.794 5.418 to 5.596 25 5.490 to 6.072 5.629 to 5.988 '
30 5.786 to 6.315 5.997 to 6.131 35 6.068 to 6.625 6.139 to 6.352 40 6.208 to 6.816 6.357 to 6.669
$ 45 6.450 to 7.252 6.670 to 7.040 50 6.715 to 7.736 7.038 to 7.353 55 7.117 to 8.072 7.352 to 7.770 60 7.512 to 8.870 7.772 to 8.303 65 7.822 to 9.543 8.331 to 8.940 70 8.514 to 9.893 8.969 to 9.648 75 9.281 to 10.44 9.677 to 10.00 i 80 9.802 to 10.09 10.02 to 10.70 85 10.48 to 11.89 10.% to 11.50 90 11.31 to 12.66 11.86 to 12.19 95 12.29 to 13.39 12.72 to 13.15 Mean = 7.905 i
t
~
Table A-4. Uncertainty Distribution for the G;:p Release Decontamination Factor at 49680 Seconds Values of the Decontamination Factor .
Percentile Characteristic of the Indicated Percentile at a Confidence Izvel, C, of C = 90% C = 50% j 5 57.90 to 68.73 61.72 to 65.92 i 10 66.04 to 79.87 69.19 to 74.68 15 73.95 to 87.59 79.58 to 82.04 20 80.57 to 98.53 84.67 to 90.20 l 25 89.00 to 106.7 93.30 to 101.0 30 97.36 to 111.0 102.I to 108.2 35 106.5 to 120.2 108.4 to 112.4 40 -109.1 to 129.2 112.6 to 122.6 115.1 to 137.5 122.6 to 134.7
$ 45 50 125.0 to 144.7 134.7 to 138.4 55 136.1 to 153.8 138.4 to 147.6 60 141.4 to 172.8 147.6 to 158.7 65 149.3 to 185.4 159.5 to 176.5 ,
70 163.6 to 194.0 ' 176.6 to 188.4 75 181.5 to 206 8 189.7 to 197.2 80 193.8 to 221.1 200.6 to 217.3 85 209.8 to 233.8 219.6 to 227.4 90 222.8 to 265.4 233.3 to 241.9 95 248.7 to 306.8 266.9 to 291.8. ,
Mean = 148.7
Table A-5. Uncertainty Distribution for the Gap Release Decontamination Factor at 86450 Seconds Values of the Decontamination Factor Percentile Characteristic of the Indicated Percentile at a Confidence Izvel, C, of C = 90% C = 50% ,
r 5 928.6 to 1132 1007 to 1090 10 1099 to 1548 1185 to 1378 15 1354 to 1803 1441 to 1671 20 1642 to 1969 1696 to 1864 25 1810 to 2199 1882 to 2036 30 1951 to 2413 2051 to 2266 t
35 2101 to 2586 2275 to 2513 40 2344 to 2848 2524 to 2665 2555 to 3024 2668 to 2903
$ 45 50 2705 to 3233 2903 to 3090 55 2934 to 3426 3090 to 3258 60 3155 to 3614 3259 to 3490 65 3312 to 4082 3494 to 3661 70 3524 to 4526 3667 to 4245 75 3811 to 4753 4269 to 4622 80 4487 to 5431 4693 to 5108 t 85 4758 to 5892 5278 to 55%
90 5524 to 6654 5779 to 6169 95 6379 to 9303 6801 to 7608 Mean = 3409 i i
_ _ _ . _ _ _ _ _ . _.___-_.a._________.____- _ _ _ _ _ _ _ ___.______ _ _ _ _ -. _- _ ___ _ _ _ _ . _- __e: _. - __ _e w - -
__r . _ . _____. _ _ _ _ __ _
Table A-6. Uncertainty Distribution for the In-Vessel Release Decontamination Factor at 6480 Seconds Values of the Decontamination Factor Percentile Characteristic of the Indicated Perceutile at a Confidence 12 vel, C, of C = 90% C = 50%
5 1.220 to 1.227 1.221 to 1.224 10 1.225 to 1.237 1.227 to 1.235 15 1.232 to 1.245 1.237 to 1.242 20 1.239 to 1.248 1.244 to 1.246 25 1.245 to 1.253 1.246 to 1.250 30 1.248 to 1.257 1.250 to 1.255 35 1.252 to 1.259 1.255 to 1.257 40 1.256 to 1.262 1.258 to 1.260 {
.b 45 1.258 to 1.265 1.260 to 1.263 50 1.261 to 1.267 1.263 to 1.265 55 1.264 to 1.269 1.265 to 1.268 60 1.266 to 1.272 1.268 to 1.269 65 1.268 to 1.273 1.269 to 1.272 70 1.270 to 1.278 1.273 to 1.275 75 1.273 to 1.282 1.276 to 1.280 l
80 1.278 to 1.235 1.281 to 1.283 85 1.282 to 1.292 1.284 to 1.287 90 1.286 to 1.297 1.289 to 1.296 95 1.296 to 1.302 1.298 to 1.302 Mean = 1.263
T r summme - - m m m w Table A-7. Uncertainty Distribution for the in-Vessel Release Decontamination Factor at 13680 Seconds Values of the Decontamination Factor Percentile Characteristic of the Indicated Percentile at a Confidence Level, C, of C = 90% C = 50%
l 5 2.821 to 2.996 2.899 to 2.954 10 2.964 to 3.160 3.005 to 3.119 15 3.104 to 3.356 3.142 to 3.267 20 3.200 to 3.458 3.312 to 3.415 25 3.358 to 3.616 3.420 to 3.504 30 3./16 to 3.782 3.525 to 3.680 35 3.573 to 3.987 3.688 to 3.819 40 3.719 to 4.133 3.824 to 4.032
- 45 3.900 to 4.351 4.034 to 4.229 50 4.070 to 4.606 4.228 to 4.411 55 4.260 to 4.899 4.411 to 4.672 60 4.457 to 5.290 4.675 to 5.000 J 65 4.743 to 5.539 5.010 to 5.416 l 70 5.214 to 6.008 5.433 to 5.655 75 5.523 to 6.233 5.759 to 6.088 80 5.929 to 6.783 6.166 to 6.487 85 6.2?5 to 7.261 6.582 to 6.926 l 90 6.861 to 7.476 7.192 to 7.376 95 7.408 to 7.949 7.518 to 7.789 Mean = 4.759
1 1 - unum umme umme ummu ammu ummu -- w Table A-8. Uncertainty Distribution for the In-Vessel Release Decontamination Factor at 49680 Seconds Values of the Decontamination Factor Percentile Characteristic of the Indicated Percentile at a Confidence Level, C, of i
C = 90% C = 50%
5 36.50 to 42.76 38.57 to 41.48 10 41.67 to 47.76 43.39 to 45.95 15 45.72 to 53.75 47.50 to 50.19 20 48.38 to 59.38 52.10 to 55.56 25 53.85 to 63.96 55.73 to 60.97 30 58.38 to 67.01 61.18 to 64.67 35 63.04 to 72.02 64.79 to 68.03 40 66.09 to 77.35 68.25 to 73.39 y
6 45 70.61 to 82.78 73.43 to 79.58 50 74.64 to 87.96 79.54 to 83.82 55 81.04 to 93.23 83.78 to 88.46 60 86.34 to 105.3 88.48 to 97.79 65 89.05 to 112.0 97.88 to 105.7 70 99.49 to 117.8 106.2 to 113.6 75 108.9 to 125.1 114.1 to 119.8 80 116.6 to 130.9 120.9 to 128.3 85 125.6 to 140.6 129.7 to 134.0 90 133.6 to 156.4 138.5 to 146.1 95 149.3 to 175.8 157.1 to 168.5 Mean = 89.25 m -
Table A-9. Uncertainty Distribution for the In-Vessel Release Decontamination Factor at 86450 Seconds Values of the Decontamination Factor Percentile Characteristic of the Indicated Percentile at a Confidence Level, C, of C = 90% C = 50%
5 585.6 to 719.9 640.4 to 685.1 10 594.9 to 975.4 747.5 to 862.6 15 835.8 to 1102 891.5 to 1019
-20 1000 to 1198 1029 to 1150 25 1107 to 1349 1154 to 1232 30 1176 to 1456 1244 to 1386 35 1278 to 1584 1390 to 1526 40 1424 to 1722 1528 to 1620 3
$; 45 1547 to 1859 1620 to 1761 50 1649 to 1926 1761 to 1878 55 1800 to 2019. 1878 to 1964 60 1891 to 2140 1%5 to 2041 65 1993 to 2379 2049 to 2175 70 2097 to 2679 2183 to 2517 75 2333 to 2862 2555 to 2773 80 2675 to 3175 2813 to 3069 85 2865 to 3421 3133 to 3305 90 3236 to 3844 3373 to 3634 95 3786 to 5332 3924 to 43%
Mean = 2032
Table A-10. Uncertainty Distribution for the Effective Decontamination Coefficient During the Interval 0 to 1800 Seconds Values of the Effective Decontamination Coefficient (hr'I)-
Percentile Characteristic of the Indicated Percentile at a Confidence I2 vel, C, of C = 90% C = 50%
5 0.332 to 0.340 0.333 to 0.335 10 0.337 to 0.349 0.342 to 0.346 15 0.345 to 0.354 0.348 to 0.352 20 0.350 to 0.359 0.352 to 0.356 25 0.355 to 0.363 0.357 to 0.362
- 30 0.359 to 0.366 0.362 to 0.363 35 0.362 to 0.369 0.364 to 0.367 40 0.364 to 0.372 0.367 to 0.370 45 0.367 to 0.374 0.370 to 0.373 50 0.371 to 0.376 0.373 to 0.375 55 0.373 to 0.378 0.375 to 0.377 60 0.376 to 0.380 0.377 to 0.378 65 0.377 to 0.384 0.378 to 0.381 70 0.379 to 0.389 0.381 to 0.386 75 0.383 to 0.392 0.386 to 0.390 80 0.389 to 0.3% 0.390 to 0.394 85 0.392 to 0.404 O.394 to 0.399 90 0.398 to 0.410 0.402 to 0.407 95 0.408 to 0.414 0.410 to 0.412 Mean = 0.373 hr'I
. _ _ _ _ _ _ _ _ _ _ _ _ _ - . - _ . . . . _ _ _ ~ , . . . -- - - - - - -
Table A-11. Uncertainty Distribution for the Effective Decontamination Coefficient for Gap Release Material During the Interval 1800 to 6480 Seconds Values of the Effective Decontamination Coefficient (hr-3)
Percentile Characteristic of the Indicated Percentile at a Confidence 12 vel, C, of C = 90% C = 50%
5 0.367 to 0.378 0.368 to 0.373 10 0.374 to 0.389 0.379 to 0.385 15 0.383 to 0.399 0.388 to 0.395 20 0.390 to 0.405 0.398 to 0.402 25 0.399 to 0.411 0.403 to 0.4%
30 0.404 to 0.416 0307 to 0.414 35 0.409 to 0.419 0.414 to 0.417 40 0.415 to 0.423 0.417 to 0.420 45 0.418 to 0.426 0.420 to 0.424 50 0.421 to 0.429 0.424 to 0.427 55 0.425 to 0.431 0.427 to 0.430 60 0.427 to 0.435 0.430 to 0.432 65 0.431 to 0.439 0.432 to 0.436 70 0.434 to 0.445 0.436 to 0.441 i 75 0.438 to 0.449 0.442 to 0.447 80 0.444 to 0.455 0.447 to 0.452 l 85 0.449 to 0.464 0.452 to 0.457 90 0.456 to 0.472 0.462 to 0.470 ,
95 0.470 to 0.479 0.472 to 0.477 Mean = 0.424 hr-I
Table A-12. Uncertainty Distribution for the Effective Decontamination Coefficient of In-Vessel Release Material During the Interval 1800 to 6480 Seconds Values of the Effective Decontamination Coefficient (hr-I)
Percentile Characteristic of the Indicated Percentile at a Confidence Ixvel, C, of C = 90% C = 50% ,
5 0.153 to 0.157 0.153 to 0.155 10 0.155 to 0.164 0.157 to 0.162 15 0.160 to 0.168 0.164 to 0.166 20 0.164 to 0.170 0.168 to 0.169 25 0.168 to 0.174 0.169 to 0.172 30 0.170 to 0.176 0.172 to 0.175 35 0.172 to 0.177 0.175 to 0.176 I 40 0.175 to 0.179 0.176 to 0.178 '
i.a 45 0.176 to 0.181 0.178 to 0.180 ,
50 0.178 to 0.182 0.180 to 0.181 55 0.180 to 0.183 0.181 to 0.182 60 0.181 to 0.185 0.182 to 0.183 i 65 0.183 to 0.186 0.183 to 0.185 70 0.184 to 0.189 0.186 to 0.187 75 0.186 to 0.191 0.188 to 0.190 80 0.188 to 0.193 0.190 to 0.192 [
85 0.191 to 0.197 0.192 to 0.194 ;
90 0.193 to 0.200 0.195 to 0.199 95 0.200 to 0.203 0.200 to 0.203 !
Mean = 0.179 hr-I l
[
Table A-13. Uncertainty Distribution for the Effective Decontamination Coefficient During the Interval 6480 to 13680 Seconds Values of the Effective Decontamination Coefficient {hr'I)
Percentile Characteristic of the Indicated Percentile at a Confidence Ixvel, C, of C = 90% C = 50%
5 0.417 to 0.441 0.424 to 0.434 10 0.435 to 0.461 0.443 to 0.454 15 0.453 to 0.487 0.459 to 0.477 20 0.468 to 0.506 0.482 to 0.491 25 0.487 to 0.525 0.493 to 0.513 30 0.503 to 0.545 0.514 to 0.533 35 0.518 to 0.576' O.534 to 0.549 g 40 0.541 to 0.594 0.549 to 0.584 45 0.566 to 0.615 0.585 to 0.603 50 0.585 to 0.644 0.603 to 0.623 55 0.609 to 0.678 0.623 to 0.653 60 0.628 to 0.717 0.653 to 0.692 65 0.662 to 0.738 0.693 to 0.726 70 0.703 to 0.779 0.726 to 0.746 75 0.734 to 0.800 0.752 to 0.788 80 0.771 to 0.837 0.790 to 0.819 85 0.804 to 0.868 0.828 to 0.858 90 0.850 to 0.887 0.865 to 0.876 95 0.880 to 0.913 0.890 to 0.906 Mean = 0.639 hr-I
o - - umune - - - - umma Table A-14. Uncertainty Distribution for the Effective Decontamination Coefficient During the Interval 13680 to 49680 Seconds Values of the Ilffective Decontamination Coefficient (hr-I)
Percentile Characteristic of the Indicated Percentile at a Confidence Izvel, C, of C = 90% C = 50%
5 0.257 to 0.266 0.260 to 0.264 10 0.264 to 0.272 0.266 to 0.269 15 0.268 to 0.276 0.272 to 0.274 20 0.273 to 0.281 0.275 to 0.279 25 0.277 to 0.283 0.279 to 0.282 30 0.281 to 0.286 0.282 to 0.284 35 0.282 to 0.288 0.285 to 0.286 40 0.285 to 0.289 0.286 to 0.288 45 0.287 to 0.291 0.288 to 0.289 50 0.288 to 0.293 0.289 to 0.292 55 0.290 to 0.294 0.292 to 0.293 60 0.292 to 0.296 0.293 to 0.295 65 0.294 to 0.298 0.295 to 0.296 70 0.295 to 0.298 0.296 to 0.298 75 0.297 to 0.300 0.298 to 0.299 80 0.298 to 0.303 0.299 to 0.302 85 0.300 to 0.306 0.303 to 0.305 90 0.304 to 0.310 0.306 to 0.308 95 0.309 to 0.315 0.311 to 0.312 Mean = 0.289 hr-I i
Table A-15. Uncettainty Distribution for the Effective Decontamination Coefficient During the Interval 49680 to 86450 Seconds Values of the Effective Decontamination Coefficient (hr-I)
Percentile Characteristic of the Indicated Percentile at a Confidence Ixvel, C, of C = 90% C = 50%
5 0.262 to 0.270 0.264 to 0.266 10 0.268 to 0.278 0.270 to 0.276 15 0.273 to 0.283 0.278 to 0.280 20 0.279 to 0.287 0.281 to 0.284 25 0.283 to 0.291 0.285 to 0.288 30 0.286 to 0.294 0.289 to 0.291 35 0.290 to 0.297 0.292 to 0.296
$ 40 0.292 to 0.299 0.295 to 0.297
- 0.297 to 0.299 45 0.296 to 0.301 50 0.298 to 0.303 0.299 to 0.301 55 0.300 to 0.305 0.301 to 0.303 60 0.302 to 0.308 0.303 to 0.306 65 0.304 to 0.312 0.306 to 0.309 70 0.306 to 0.314 0.309 to 0.312 75 0.310 to 0.318 0.313 to 0.315 80 0.314 to 0.321 0.316 to 0.319 85 0.319 to 0.329 0.320 to 0.325 90 0.324 to 0.336 0.328 to 0.334 95 0.334 to 0.340 0.336 to 0.338 Mean = 0.301 hr'I
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Table A-16. Uncertainty Distribution for Time-Averaged Decontamination Coefficient for thePeriod 0 to 1800 Seconds Values of the Time-Averaged Decontamination Coefficient (hr-I)
Percentile Characteristic of the Indicated Percentile at a Confidence Ixvel, C, of C = 90% C = 50%
1 5 0.4614 to 0.4823 0.4717 to 0.4799 10 0.4751 to 0.5012 0.4803 to 0.4971 I
15 0.4844 to 0.5078 0.4983 to 0.5050 20 0.5003 to 0.5138 0.5048 to 0.5093 25 0.5051 to 0.5187 0.5088 to 0.5164 30 0.5093 to 0.5230 0.5139 to 0.5188 35 0.5143 to 0.5261 0.5185 to 0.5234
> 40 0.5186 to 0.5292 0.5218 to 0.5262 G 45 0.5221 to 0.5339 0.5257 to 0.5292 50 0.5257 to 0.5359 0.5271 to 0.5339 55 0.5272 to 0.5386 0.5335 to 0.5360 l 60 0.5337 to 0.5474 0.5350 to 0.5387 i 65 0.5351 to 0.5544 0.5383 to 0.5484 l'
70 0.5384 to 0.5602 0.5429 to 0.5556 75 0.5467 to 0.5715 0.5543 to 0.5603 80 0.5560 to 0.5765 0.5602 to 0.5726 85 0.5613 to 0.5879 0.5725 to 0.5809 l 90 0.5744 to 0.5948 0.5816 to 0.5917 95 0.5899 to 0.6071 0.5935 to 0.6012 Mean = 0.5342 hr-I l
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