ML20054E136
| ML20054E136 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 03/30/1982 |
| From: | Lempges T NIAGARA MOHAWK POWER CORP. |
| To: | Haynes R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| Shared Package | |
| ML20054E127 | List: |
| References | |
| NMP-4321, NUDOCS 8204260173 | |
| Download: ML20054E136 (10) | |
Text
-
9 M V NIAGARA '
RUMOHAWK-NuP-4321 NBAGARA MOHAWK POWER CORPORATION /300 ERIE BOULEVARD WEST, SYRACUSE, N Y.13202/ TELEPHONE (315) 4741511 March 30, 1982 bit. Ronald C. Haynes Regional Admittistrator United States Nuclear Reguiatory Comnission Region 1 631 Park Avenue King of Prussia, PA 19406 RE: Docket No. 50-220 DPR-63 Dear klt. Haynes Your Letter of January 25, 1982, requested Niagara Mohawk.to repeat our pteviously submitted evalua{lon for the field detection and measurement af airborne radiciodines.
Our tetter of Februaruj 18, 1982, requested a delay in the submittal of titis data untti March 31, 1982. This letter transmitts the re-evaluation requested by your staff in the aforementioned correspondence.
Enetosure I provides a re-evaination of our abilittj to rapidly and acctuuttely detect and measure airborne radiciodine concenttations under field conditions.
Niagara Mohawk believes that titis transnittat satisfies the comnLt-mestt made to your staff on January 6, 1982.
Please contact me at your earliest convenience if the infonnation does not meet willt your approval.
You may be assured af our contu1ued cooperation.
Vetuj tuly yours igemtLL ff Thomas E. Lempges Vice President Nuclear Generation TEL/jm Ga 8204260/ 73
ENCLOSURE I Re-evaluation of the Detection and Measurement of Airborne Radioiodine Under Field Conditions I.
INTRODUCTION A rapid means of detecting airborne radioiodine activity during an emergency is necessary to expedite the identification of the plume centerline and the recommendation of protective actions to the general public.
As a result of the NRC Emergency Preparedness Appraisal (Inspection No. 81-18), the NMPNS re-evaluated it's ability to detect radio-iodine in the field.
This evaluation was completed and transmitted to the Commission on October 20, 1981. Subsequently, Region I stafi j
members (Messrs. Crocker, Kottan and Ms. Mojta) during a telephone conversation on January 6,1982, with P. Volza of our staff, requested that this evaluation be repeated. Areas to be addressed during the re-evaluation should include:
a.
Use of I-131 as the predominate source of iodine when determining detection efficiency b.
Ilomogenous mixing of source in first third of i
sampling cartridge c.
Use of survey meter resolving time when calculating MDC/MDA The radioiodine detection efficiency determined as a result of this re-evaluation will.be incorporated into appropriate emergency impic-menting procedures to provide an expeditious evaluation of airborne radioiodines released during an emergency condition.
II.
METil0DOLOGY l
Six (6) SAI CP-100 charcoal sampling cartridges were face loaded with l
I-131 by Analytics, Inc. of Atlanta, Georgia. This loading involved the homogenous mixing of the I-131 source onto the first 5 mm. of the sampling cartridge. A complete description of the loading technique and its supporting documentation is provided in Attachment 1 to this report.
Upon receipt from Analytics, the cartridges were analyzed on the Station GeLi to verify their deposited activity.
Each cartridge was subsequently counted using an Eberline RM-14 countrate meter and an llP-210 Geiger Muller probe. The probe was held approximately 1/2 to 3/4 inch from the cart-ridge and counted for a total time of 1 minute in a low background area
(< 100 cpm). The maximum value obtained during the 1 minute count time was recorded and subsequently used to determine the detection efficiency.
Each cartridge was counted three (3) times to ensure reproducibility and proved an adequate sample data base.
~
II.
METHODOLOGY (Continued)
Background determinations were performed using a clean CP-100 cartridge and counted in the same manner as the loaded cartridges. Additionally, background was also determined by holding the probe free in air.
Since there was no difference observed between the two readings, either method could be used in determining background values.
The data obtained during the GeLi and RM-14/HP-210 analyses were used to determine total deposited activity and observed count rate respec-tively.
The recorded data was subsequently used to determine radio-iodine detection efficiency and analyzed for significance at the 90%
confidence level.
% efficiency = Total count rate (cpm) - background count rate (cpm)
Tctal Activity (dpm) x 100 III. RESULTS The data collected is presented and summarized in Table 1.
This data was evaluated for acceptance using Chavenet's Criterion for Rejection.
(where n=3, and Xi-x <1.37)
Sn-1 Since the ratio of the deviation over the standard deviation did not exceed 1.37, the data was considered acceptable. The results of this acceptance evaluation can be found in Table 2.
Furthermore, the results were also analyzed via the T distribution to determine the confidence interval for the mean.
It was found that the results indicated a 90%
confidence interval for the mean assuming a normal distribution. The results of this evaluation can also be found in Table 2.
IV.
CONCLUSION Based on the data presented in section III of this report, an average efficiency of 0.49% would be more than adequate in estimating field airborne radioiodine concentrations following an accident.
Furthermore, using the average efficiency indicated above and the sampling / analysis requirements currently contained in appropriate emergency implementing procedures, pCi/cc as required per NUREG 0654, can be easily achieved the ability to detect and measure radioiodine concentrations of 1 x 10 (See Table 3).
It is, therefore, anticipated that appropriate emergency implementing procedures will be revised by July 1,1982, to incorporate the detection efficiency determined as a result of this evaluation.
ATTACFMENT I
)
/ INALYTICS, INC.o1094 HEMPHILL AVE., N.W.o ATLANTA, GA. 30318c(404) 876-0933
,o Marr.h 8, 1982 U
Mr. Tim Kurtz NIAGARA FOHAWK POWER COMPANY Nine Mile Point Nuclear Station P. O. Box 32 Lycming, NY 13093
Dear Tim:
We received your cartridges for fabrication today and would like to remind you of our change of address as indicated above. Our shipping schedule calls for the six (6) cartridges to be sent to you by Pegis-tered Mail on Monday, March 15.
As you requested, may I give you a brief description of our face loading procedure on charcoal cartridges. Ibting the direction of flow on the cartridge, we open the exit face and remve the charcoal. For gama counting, we place a layer of parafilm inside the entrance face of the cartridge. The desired radionuclide is evaporated onto a 5m layer of charcoal in the cartridge. This active layer is then covered with a layer of parafilm, and the remaining charmal is returned to the cartridge. 'Ihe exit face is now replaced with silicone soalant. As you requested, no layer of parafilm will be placed between the active char-q coal and the entrance face on your I-131 cartridges, b
I have enclosed for your review a graph we charted after having dissected many charcoal cartridges from an I-131 dispensing facility.
'Ihis data shows the distribution of I-131 by depth on the charcoal. It was from this data that we developed the 5m face loading procedure.
'Ihank you for your continuing support. Please call us whenever we can be of service.
Sincerely, ANALYTICS, INOORPORATED Patsy McFarland QA Manager EM:msa Enclosures 1
l m.
i A
(
/ INALYTICS, INC.e 1094 HEMPHILL AVE., N.W.e ATLANTA, GA. 30318 e(404) 876-0933
[.
- h DEPTH DISTRIBUTION OF I.131 ON CHARCOAL 18 If..
t 14 t
he ari 3
12..
Face velocity 3 0 c rr.,'s e c ey Sampling Time 4.2 days
';j 10, v
O 8
p
%o 8
R
- 6..
4 Front cartridge Back cartridge i
f 2
i t_,
0
.p 5
10 1 'c 5
10 15 20 g
2gepthmg g
j a
i
L ll A
i:
/ INALYTICS, INC.e1094 HEMPHILL AVE., N.W.e ATLANTA, GA. 30318e(404) 876-0933 c-DEPTH DISTRIBUTION OF I-131 ON CHARCOAL I'
30.p I1
\\
25,,,
l A
P
.c4> 20 '
p Face veloci':y
- 4. 8 ct 'see o
Sampling time 4.2 days i
a ad 1t e
t O
)
a 15..
1 R
10, i
Front cartridge Back cartridge 5.
~
=
^ ^
_: :,,, __,, _,, ;,, ;, ;, W e,,_,
o
.}__..-._-.
5 10 15 20 5
10 15 20 g
Depth g g
- ~ ;sJ TABLE 1 g
f{ ~
RESULTS
.s.
A.
Background /MDC Determinations!
I
Background
MDC f
60 62.6 % 63 I
80 72.2 % 72
['
90 76.6 % 77 f
B.
Radioiodine Detection Efficiencies
}-
Sample Activity (dpm)
Nuclide Total Counts (cpm)
Bkgd (cpm)
Net Counts
% Efficiency 1-a 3.57x10 I-131 1800 80 1720 0.48 i
5 5
b 3.57x10 I-131 1800 80 1720 0.48 5
c 3.57x10 I-131 1600 80 1520 0.43 5
2-a 7.18x10 I-131 2800 80 2720 0.38 5
b 7.18x10 I-131 3000 80 2920 0.41 c
7.18x10 1-131 3000 80 2920 0.41
['
5 5
3-a 3.36x10 I-131 1800 80 1720 0.51 b
3.36x10 I-131 1800 80 1720 0.51 l
5 c
3.36x10 I-131 1700 80 1620 0.48 L
5 l
5 4-a 6.76x10 I-131 3000 80 2920 0.40 5
b 6.76x10 I-131 3200 80 3120 0.46 5
c 6.76x10 I-131 2900 80 2820 0.42 5-a 6.68x10" I-131 420 80 340 0.51 b
6.68x10" I-131 480 80 400 0.60 c
6.68x10" I-131 500 60 440 0.66 l
I i
i i
~
e e
e m
r i
TABLE 1 (Cont'd.)
i F-B.
Radiciodine Detection Efficiencies (Continued)
Sample Activity (dpm)
Nuclide Total Counts (cpm)
Bkgd (cpm)
Net Counts
% Efficiency 6-a 7.11x10" I-131 500 80 420 0.59 i
b 7.11x10' I-131 480 90 390 0.55 c
7.11x10" I-131 480 80 400 0.56 I
I i
Average 0.49%
i f
l NOTES y
V Total Bkgd. Count Rate 1.
F0C = 4.66 Bkgd. Count-time r
Note that background count-time was 20 seconds.
j This time corresponds to the time response characteristic quoted by the manufacturer as necessary to reach 90% of the equilibrium countrates.
{>
t i
I-i I
n._
f 5
)
e i
9 4
e e
e i
i
l TABLE 2 I
i Summary of Statistical Evaluation of Data
[
i No. of Counts i
Chavenet's Criterion in one minute
- a/2 i+ta/23 f
Samp19 for Rejection i cpm Sn-1 7 + S/ Yn Th~
-f ii-Ip 1-1653 115.5 1653 + 67 195 1653 4 195 a
0.58 b
0.58 c
1.15
[
2-2853 115.5 2853 + 67 195 2853 + 195 c
1.15 1,
b 0.58 c
0.58 l
5 3-1687 57.7 1687 + 33 97 1687 + 97 l
a 0.57 b
0.57 l
c 0.44 k
4-2953 152.8 2953 + 88 258 2953 + 258 a
0.22 b
1.09 c
0.87 e
5-393 50.3 393 + 29 85 393 + 85 i
n 1.05 i,
b 0.14
}-
c 0.93 6-403 15.3 403 + 9 26 403 + 26
[
a 1.11 i
b 0.85
)
c 0.20 L
NOTES I
1.'
hhere n = 3, thenlxi-7/Sn-1l < 1.37 for acceptance 2.,
90% con ence interval where ta/2 = 2.920, u (degree of edom) = n-1 = 2
TABLE 3 Counting Statistics for Uso of RM-14/HP-210 to D3tect Radiciodines on Chsrcoal/ Silver Zsolite Certridge in the Field
+
A.
Given__:
1.
Air Sample Volume - 15 ft.3 and 20 ft.3 2.
Cartridge Retention. Efficiency for Radiciodines -
Silver Zeolite - 95%
TEDA-Charcoal (cp-100) - 99%
3.
Background - 100 cpm or less 4.
Radioiodine Detection Efficiency
.49%
5.
MDA =
MDC (6. 28x10 '
- dpm-cc) 3 (ft') (efficiency of (efficiency of U Ci-ft Detection) cartridge retention)
B.
Minimum Detectable Activities per Given Data 3
2 Count Time Air Vol.
Bkgd.
bkgd (cpm)_
(uCi/cc)
Using Silver (uCi/cc) 3 (ft )
(cpm) l.333 min.
Zeolite Using CP-100
-8 1 min.
15 100 81 1.85x10 1.77x10-8
-s 1 min.
20 100 81 1.71x10 1.64x10-s NOTES:
1.
Count time to observe maximum value (3 counting intervals).
2.
Based on instrument resolving time of 20 seconds (.333 min.).
i i
O
,. m W W; 7. P, -e
$N 84*4*
y
-. W yew
-v_
y4y W *9
-y g4s>
- i Pf988mM9 F W$%***
- h he v