ML20215D793
| ML20215D793 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 11/26/1986 |
| From: | Sieber J DUQUESNE LIGHT CO. |
| To: | Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| NUDOCS 8612170038 | |
| Download: ML20215D793 (16) | |
Text
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'Af Telephone (412) 393 600o Nuclear Group
$0ppYn*gp#
' November 26, 1986 cri, pA iso 77.ooo4 U. S. Nuclear Regulatory Commission Office of Inspection and Enforcement Attn:
Dr. Thomas E. Murley, Regional Administrator Region 1 631 Park Avenue King of Prussia, PA 19406
Reference:
Beaver Valley Power Station, Unit No. 1 Docket No. 50-334, License No. DPR-66 Unresolved Item 83-30-05 Radiation Monitor Study Particle Distribution Evaluation, June 1986 Gentlemen:
During the period of inspection BV-1-86-25, your Messrs. McFadden and LeQuia discussed, with members of my staff, some aspects of our response related to unresolved item 83-30-05.
The unresolved item questioned the ability of the radiation monitoring system to collect representative samples.
Although the information in our report supports our conclusion that our monitoring capabilities and compensatory actions already inplace address the possible underestimation of effluent
- releases, the stated conclusion in the submittal cover letter contained an error, which in turn, appeared to negate our conclusion.
This letter draws upon information in the report and clarifies our position.
As we noted in our prior responses on this item, our practice has been to add a level of conservatism to our effluent t 1culations by halving the actual monitor sample flow.
This flow value is in the denominator and results in a factor of 2 (100%) i;. crease estimated release activity and offsite dose.
Also, we use design system flow rates in lieu of lower actual flow rates which results in additional conservatism.
In our submittal cover letter we had erroneously concluded that this 100%
increase would compensate for the observed worst case bias of
-87% (by volume).
If the particle measurement was low by -87%, it would take a correction factor of 7.7 to compensate, and not a factor of 2
as our existing procedures provide.
While this would seem to support the NRC concern that we are underestimating the particulate contribution to effluent release rates, we conclude that there are sufficient data in the body of our report to show with reasonable assurance that effluent release activities have not and are not being underestimated.
8612170038 861126 gI PDR ADOCK 05000334 O
_gg
m B'nv2r Valley Power Station, Unit No. 1 e
Docket-No. 50-334,rLicense No. DPR-C6 Unresolved Item 83-30-05 Radiation Monitor Study Particle Distribution Evaluation, June 1986' 1Page 2
~
The sample line efficiencies listed in the conclusion section of the referenced report are. worst case observations based on particles found per electron microccope frame and on concentrations determined by the area under the normalized distribution curves.
These data are provided on.page 83 of_our report.
These data indicates that the bias between monitors varies widely between-number, surface area and-volume.
This is because for an equal amount-of 1 M-10WM particles, their respective ratios are:
1/1 on a number basis, 1/100 on a surface area basis, and 1/1000 on a volume basis.
If only particle number distributions are used, then the conclusions could be grossly misleading.
Assuming that the
_ density of. the sample is -the same, then the volume concentration would be equivalent to mass concentration.
The response of the radiation monitor to particulate activity deposited on filter paper is best.repre'sented by the mass concentration.
As we noted in -the report, the statistical quality of the 1984 particulate study results were affected by the very low particulate radioactivity present.
This was the. reason for having the electron microscope particle study performed.
However, as we have noted in
-the
- report, the= data is affected by statistical considerations related to the number of samples and the requisite sampling conditions.
An increased number of samples would reduce the error term. associated with each mean ratio, and we believe, the mean ratio as well.
We call your attention to Figures 8-13 (pages 72-77) of our report which present the average bias for the sampling combinations.
While these figures show some negative bias as expected, it must be
. recognized that these regions of negative bias fall primarily outside of.the 0.1 M
-- 10WM particle size range supported by the particle size distribution results (Figures 14, 15; pages 79, 80).
Qualitatively integrating the particle size distribution on the special isokinetic sample rig with the average bias shown on Figures 8-13 leads us to conclude that it is likely that our effluent measurement
_ program overestimates rather than underestimates particulate radioactivity, and that our present effluent analysis correction factors-provide additional assurance to this effect.
4 3
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e-Beaver Valley' Power Station, Unit No. 1 Docket No. 50-334, License No. DPR-66 Unresolved Item 83-30-05 Radiation Monitor Study Particle Distribution Evaluation, June 1986 Page 3 While-additional sampling and analysis could be performed to reduce the analysis errors associated with the current results, we do not believe that additional data thus gained would significantly cffect our conclusion.
We apologize for any inconvenience caused by confusion over our submittal cover letter.
Attached are revised corrected pages for insertion in our June, 1986 Particle Distribution Evaluation.
Please contact my office if there are additional questions regarding this issue.
Very truly yours,
. D. Sieber Vice President Nuclear Operations cc: Mr. W. M. Troskoski, Resident Inspector U.-S. Nuclear Regulatory Commission Beaver Valley Power Station Shippingport, PA 15077 U. S. Nuclear Regulator */ Commission c/o Document Management Branch Washington, DC 20555 Director, Safety Evaluation & Control Virginia Electric & Power Company P.O. Box 26666 One James River Plaza Richmond, VA 23261 i
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e Beaver Valley Power Station Unit 1
, Docket No. 50-334, License No.'DPR-66 Unresolved Item 83-30-05 Particulate' Distribution Evaluation, June 1986 Revised Pages, November 1986 Pages:
Remove Insert Description of Change iv
.iv The last paragraph of the abstract was revised to remove the reference to correction factors below 100%.
12 12 A
typographical error was corrected in Table 1
"8/13/85 SLCRS Samples Particle Size Distribution".
The SPING Volume % Bias From Test should have been
"+116%"
and not
"+1516%".
..71 71 The percent bias from the test equipment for all monitors was about -50% instead of always within -100%.
72-77 72-77 the horizontal axis scales in Figures 8
through 13 were clarified to indicate that the data was converted to Log prior to plotting.
The 1WM to 10pM area was highlighted along with correction factors assumed in the effluent release calculations.
The data remains unchanged.
- 83 83 The Gaseous Waste worst case % bias from the test for the SPING-4 on a volume basis was revised from
-59% to -87%.
This agrees with the 11/25/85 Sample Data on pages 50 and 60.
84 84 Previous correction factors assumed in effluent release calculations were revised as follows:
Ventilation Vent:
The 100% was corrected to 2
-50%.
SLCRS:
The 170% was corrected to -63%.
Gaseous Waste:
The 150%
was corrected to
-60%.
4 l
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,,- ~ -,. -
Unresolvtd Ittm 83-30-05 Particle Distribution Report Abstract Nuclepore Membrane Filter Samples were obtained from the Eberline SA 9/10 and SPING 4 monitors and compared with special test equipment.
Samples were obtained on August 13, 1985, November 25,-1985 and March 11, 1986, from the air effluent release systems.
Each sample was electron microscope analyzed by Mellon Institute to determine effluent particle distributions and key element constituents.
Particle average diameters, surface areas and volumes were determined over various ranges.
Statistical comparisons were made between the monitors -and effluent systems.
A majority of the particles collected consisted of silicates and sulfates.
A few iron (or rust) particles were also detected. Most particles were within a 0.1pM to 10pM range.
While particle plateout was the major purpose of this study, other particle behavior characteristics were also evident. They include:
1) particle agglomeration or the coagulation of smaller particles to form larger ones; 2) particle splitting or fracturing upon impact with the sample line interior walls; 3) re-suspension of large particles in sample lines.
It is likely that our effluent measurement program oycrestimates rather than underestimates particulate radioactivity, and that our present effluent analysis correction factors provide additional assurance to this effect.
Correction factors were also calculated using the guidelines in Appendix B of ANSI N13.1-1969 and found to be minimal.
-iv-
i TABLE NO.'1 i
8/13/85 SLCRS Simples Particle Size Distribution Diameter (uM)
Surface Area (uM2)
Volume (uM3)
Range Number of Pa rticles Range ILtteber of Pa rticles Range Number or Particles fuM1 SPING SA 9/10 Test fuM21 SPING SA 9/10 T e s t_,
fuM31 SPING SA 9/10 Test 0
.063 0
0 0
0 -.01 0
0 0
0
.0001 0
0 0
.063
.1 5
2 15
.01
-.016 1
0 0
.0001
.00022 7
1 19
.1
.16 36 58 130
.016
.025 7
1 22
.00022
.00046 24 27 60
.16
-.25 101 119 245
.025
.040 20 21 59
.00046
.001-38 71 148
.25
.40 214 203 500
.040 -.063 32 64 103
.001
-.0022, 58 59 129 40 -.63 349 292 506
.063
.10 52 60 154
.0022 -.0046 114 102 230 1.0 478 293 270
.10
-.16 90 94 185
.0046
.010 79 87 182
.63 1.0
- 1.6 393 153 51
.16
.25 92 80 212
.010
.022 157 96 219 1.6
- 2.5 142 27 30
.25
- 40 130 100 211
.022
-.046 175 148 264 2.5
- 4.0 26 1
11
.40
-.63 151 128-244
.046
.1 256
'186 227 4.0
- 6.3 4
0 2
.63
- 1.0 213 162 234
.1
-.22 275 154 161-1.0
- 1.6 260 164 171
.22 46
-219 118 58 1.6
- 2.5 197 110 79 46
- 1.0 190 61 15 2.5
- 4.0 223 96 33 1.0
- 2.2 94 29 15 4.0
- 6.3 139 42 10 2.2
- 4.6 41 8
13.
6.3
- 10 89 20 13 4.6
- 10 13
.I 14 10
- 16 34 5
15 10
- 22 3
0 5
16
- 25 10 1
8 22
- 46 5
0 1
25
- 40 3
0 6
40
- 63 5
0 1
O smallest:
.0659
.0879
.0879
.0149
.0219
.0172
.000133
.0002
.000156 y
- ve ra ge:
.869
.631
.490 2.34 1.25
. 949
.450
.167
.193 Std.Dev.-
1 569 1 392 1 401 13.9 11.72 12.83 11.77 1 415 11.21 Median:
.761'
.551
.397 1.20
.689
.353
.928
.043
.016 t a rges t :
4.4 2.64 4.22 51.5 17.9 42.6 33.6 6.47 23.8 Fode:
.815
.815
.515 1.30 1.30
.515
.160
.073
.034 Total Total Pa rt i c l e Total f'a rt ic l es Surface Pa rt ic l e s
/nalyzed:
1748 1148 1760 A rea :
4090 1435 1670 Volume:
787 192 340 Pa rt ic l e Surface Pa rt ic l e me Pa rt ic l es Area Volume ma i rame*/CFM:
480.2 708.6 517.6 F ra me */C F M:
1123.6 885.8 491.2 F rame*/CF M:
216.2 118.5 100 $Q n a 77l
% Bias
(-7%)
+37%
% Blas
+128%
+80%
% Bias
+116%
+18%
0 O rrom Test:
From Test:
From Test:
km s n n M m G8
- 1 E lectron Mic roscope f rame " picture" is equal to 6.42 E-5 cm2
%g W B O t,a D C MO
.g u,-
O M
rt
Unresolved It:m 83-30-05 Particle Distribution Report G.
Analytical Discussion of Data A statistical evaluation of the sample data was also performed using the volume data. The volume range was first calculated for each sample and monitor:
V(S,R,M) Where S = Sample number R = Range of Volume M = Monitor
-The difference between the monitors was calculated as follows:
D(S,R,1-2) = [V(S,R,1) - V(S,R,2)] / V(5,R,2) 0(S,R,1-3) = [V(S,R,1) - V(S,R,3)] / V(S,R,3) 0(S,R,n-m) = [V(S,R,m) - V(S,R,m)] / V(S,R,m) where n = monitor n m = monitor m The average difference was calculated as follows:
y = Avg. = I 0(S,R,M)
No. of Samples The error was calculated as follows:
4 ERR (R,M)=[(D(S,R,1)-Avg)2 + (D(S,R,2) - Avg)2 = (D(S,R,m) - Avg)2 No. of Samples The mean (p) and the error for each volume range was calculated for each monitor and plotted in Figures 8 thru 13.
The curve profiles are i
indicative of submicron particle agglomerating to form larger particles and the splitting of larger particles. The percent bias from the test equipment for all monitors was about -50% considering a 1 standard deviation error.
1 e
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FIGURE 8 r
SLCRS SPING 4 VS TEST
% BIAS 700%
,.[
AVERAGE BIAS
[Y
+
+1 Std Dev 600% -
6
-1 Std Dev 11 500% -
?.
. '.') :
+
6 s[' i uxm-
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300% -
b'. u C
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4 0
0 2-o~
S j
9 i
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.0001
.001
.01
.1 1
10 100 C.
6~
3 i
)
3 VOLUME (uM3) g O
NOTE: DATA IS CONVERTED TO LOG PRIOR TO PLOTTING.
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ca..
..,. u s.......
Unresolved item 83-30-05 P rticle Distribution Report
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FIGURE 10 VENTLATION VENT SPING-4 VS SLCRS TEST
% BIAS 300%
AVERAGE BIAS 4-
+1 Std Dev i
o
-1 Std Dev
+
200% ~
+
[,
/[.
100% --
. -L
+
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4 "A~
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i e
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g g
-50% _ ___
+ _ _ + _
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3 4
9 i
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o o
o o
j
-100%
o F
i 0
1 F
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q
.0001
.001
.01
.1 1
10 100 l
k l
9' VOLUME (uM3) i NOTE: DATA IS CONVERTED TO LOG PRIOR TO PLOTTING.
l 19 1953 HERCULENE. AGS EMITH CO., PGH.. PA LT2SSG-SSS
FIGURE 11 VENTLATION VENT SA 9/.10 VS SLCRS TEST
% BIAS 300%
AVERAGE BIAS
+
+1 Std Dev o
-1 Std Dev 200% -
+
il.:?
+
F. i -
.o<
/}.p t l
100% -
s'
+
c i
+
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+
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7 T
+
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4 O
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o F--
o_ -
+
=y i
-sos -
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o D
k I
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~
-100%
me e.e 5!
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g i
c j
.0001
.001
.01
.1 1
10 100 l
l
- s l
23 VOLUME (uM3) 8 3
i NOTE: DATA IS CONVERTED TO LOG PRIOR TO PLOTTING.
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19 9953 HEltCULENE. AGS StelTH CO PGH., PA LT20SS.SSS i
1
FIGURE 12 GASEOUS WASTE SPING-4 VS SLCRS TEST l
% BIAS 1000%
,j f
900% -
AVERAGE BIAS
+
+1 Std Dev l
o
-1 Std Dev g
g~,
f 1, l
j 700%
.-l %x},9, 600%""
h.
1
(:.
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500% -
l 4
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s ta s
l se
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i '-
1
+
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-60% - --
- - + - - + -
- cr 0- -
g-l
-100%
0 D
0
- ~
~
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l F
-200%
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E
.0001
.001
.01
.1 1
10 100 g
3 m
VOLUME (uM3) g a
NOTE: DATA IS CONVERTED TO LOG PRIOR TO PLOTTING.
IS-IISS HERCULENT. A4B SMITH CO PGM., PA LT20SS-SGS
l FIGURE 13 GASEOUS WASTE SA 9/10 VS SLCRS TEST
% BIAS 1000%
AVERAGE BIAS N-
-H
+1 Std Dev
-1 Std Dev 700% -
i l
i 500% -
e R
+
l 400% -
{
U
[q k
8
- t a
{
300%
' E.
x i
h i %1, l
+
+
j m-g
.i!
i
+
Y
+
d,
1 0%
w w
-60% -
v q---
3,
q g_.
vm i
i 0
0 0
0 o
O l-j
-100% _
g 4
a i
5f I
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I
! f
.0001
.001
.01
.1 1
10 100 23e VOLUME (uM3) 32 I
NOTE: ' DATA IS CONVERTED TO LOG PRIOR TO PLOTTING.
89 1153 HERCULENE. AGS SMITH CO., PGH., PA LT1956 905
c _ _ - - _ _
Unresolv d Itzm 83-30-05 Particle Distribution R: port H.
Conclusion (cont.)
Compared with the. test equipment, worst case percent bias for the SA 9/10 and SPING-4 was as follows:
Worst Case % Bias from the Test SA 9/10 SPING-4 Surface Surface Number Area Volume Number Area Volume SLCRS:
-21
-48%
-63%
- 7%
-38%
-46%
- Ventilation Vent
-77%
-70%
-61%
-10%
-45%
-47%
Gaseous Waste:
-95%
-91%
-87%
-93%
-68%
-87%
l The Victoreen monitors have sample line configurations very similar to the SPING-4 monitors. From our earlier report, the Victoreen Cs-137 and Co-60 activities were higher than the other two monitors.
The SPING-4 Cs-137 and Co-60 activities were also a little higher than the SA 9/10 activities previously reported.
Therefore, the Victoreen monitor correction factor should be no worse than the SPING-4 correction factor.
Based on ANSI N13.1-1969 calculations, plateout corrections factors would be negligible. Sample line loses were calculated to be minimal mainly because the effluent streamcontains small particles which travel through sample lines in a turbulent environment at high average velocities.
At Beaver Valley, effluent releases are conservatively calculated to account for sample line-loss. Another licensee has performed studies on line-loss and have arrived at correction factors-from 50% to 99%(7).
Technical Specifications, Appendix A, Section 3/4.11, Table 4.11-2, notation f (applicable to continuous sampling on the ventilation systems) states, "The average ratio of the sample flow rate to the sampled stream flow rate shall be known for the time period covered by each dose or dose rate calculation made in accordance with Specifications 3.11.2.1, 3.11.2.2, and 3.11.2.3".
Sample flow rates are averaged on a weekly basis and recorded on RCM Form 2.29 which documents iodine, particulates, and noble gas sampling and analyses.
The effluent stack flow rates are recorded each shift in the
" Radiological Control Shift Information Log".
Average ratios of the two streams for each effluent path GW-108, VS-101 and VS-107 are known but are not used for monthly dose or dose rate calculations made on continuous release system permits.
Instead of using the average ratio of the sample flow to the stack flow required, for the implied purpose of determining doses or dose rates uased i-on representative samples, maximum stack flow rates listed in ODCM Section 2.1 are used.
These discharge rates result in conservatively over estimated doses and dose rates but all doses and dose rates are far below Technical Specification limits.
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(R
.4 Unresolved Item 83-30-05 Particle Distribution Report H.
Conclusion (cont.)
In -the' past, the actual ratio of these two averages was not used for dose and dose rate determination.
Previous correction factors used are described in the calculation below:
ODCM Values + Average System Flows = Conservative Factors Stack Flow = 62,000 cfm + =62,000 cfm
=2 or -50% (Vertilation Vent)
=
2 cfm Sample Flow I cfm
=
Stack Flow 49,300 cfm + =36,000 cfm
=2.7 or -63% (SLCRS)
=
Sample Flow =
1 cfm 2 cfm
=
Stack Flow 1,200 cfm + =
950 cfm
=2.5 or -60% (Gaseous Waste)
=
Sample Flow, I cfm
=
2 cfm This method of estimation was done intentionally when the hand calculation procedures for gaseous doses and dose rates were prepared. These procedures were prepared during the last calendar quarter of 1983, ie., after the NRC inspection.
In conclusion, the correction factors determined in this report are all within the conservative calculational factors used for effluent release data. !
--