ML20090L558
| ML20090L558 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 03/16/1976 |
| From: | Mayer L NORTHERN STATES POWER CO. |
| To: | Stello V Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 9102110419 | |
| Download: ML20090L558 (7) | |
Text
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
3 t-NSE2 NORTHERN 5TATES POWER COMPANY MINN E A POLIS. MlN N E SOTA S5401 March 16, 1976 cQ g.7 ya@pt E8 'l4;7Q6'l 6 JgO Mr. Victor Stello, Director l.
Division of Operating Reactors
,g N '*r C
U.S. Nuclear Regulatory Comission V
Washington, DC 20555 d
'.2/
Dear Mr. Stello MONTICELLO NUCLEAR GENERATING PIANT Docket No. 50-263 License No. DPR-22 Additional Infomation Concerning November,1975 Primary Containment Integrated Leckage Rate Test Attached you will find 40 copies of " Supplement No.1 to Report of Reactor Containment Building Integrated Leak Test-November,1975".
This report is submitted in response to a request from the Region III Office of Inspection and Enforcement.
This supplemental report contains an " Instrumentation Error Analysis" for the instrumentation used in the 1975 testing program.
Yours very truly, h,
L. O. Mayer, PE Manager, Nuclear Support Services LQ4/IEM/ deb C(
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J. G. Keppler k
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Attn:
J. W. Ferman Attachmeat 9102110419 760316 gDR ADOCK050g23 gg l
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NOR111ERN STATES POWER CCMPANY MONTICELLO NUCLEAR GENERATING PIANT Docket No. 50-263 License No. DPR-22 Supplement No. I to Report of Containment Building Integrated Leak Test November 1975 Date: March 16,1976
l
. 1.
Background
he original test report contained a calculation of the 957 confidence interval associated with the leakage rate measurement using a standard T-distribution error analysis.
Since 10 CFR 50, Appendix J states that test reports shall include an " instrumentation error analysis", we have been requested to supply an error analysis based on certified instru-ment accuracies.
An instrumentation error analysis was included in test reports submitted in 1970, 1973, and 1974.
We analysis was repeated in the 1974 and 1975 reports because the instrumentation was significantly upgraded from pre-vious tests. We instrumentation used in the 1975 test program was identical to the instrumentation used in 1974 testing. An instrument error analysis using the 1975 test parameters is repeated and the results are seen to be essentially identical to those reported in 1974 In the future our test reports will reference the instrumentation error analysis performed earlier unless changes in the test instrumentation require a revised analysis. The standard statistical T-distribution error calculation is a more rigorous determination of probable testing error and will continue to be made and reported following each test.
2.
Instrumentation Error Analysis The assumptions for the type A test error analysis and the derivation of the type A test error relation may be found in the sumary technical report entitled REACTOR CCNTAINMENT BUILDING INTEGRATED LEAK TEST, May 1973, he estimated variance for each type A test measurement are as given below:
2 a)
Estimate of 6 (T)
All temperature measurements were obtained with ALP 11A-LINE RTD transmitters connected to the plant process computer.
his system has an accuracy over the range of 600F to 170 F of at least 0.10 F, h erefore:
6 (tt) = (0.10)2 2.5 x 10-3 O 2 2
R
=
2 Applying the weighting factors used in the test:
i=20 T=
wtit i=1 i=20 2
2
-4 2
2 ( T } = (6. 7 x 10-2 )(2. 5 x 10-3 ) = 1. 67 x 10 f ( T)=
i i=1
2 b)
Estimate of 62 (P)
The Wallace Tiernan gauge used to measure the contairunent pressure is readable to 0.012 PSIG and has a certified accuracy of 0.04 PSIG.
We barometric pressure instrument is readable to 0.01 INCHES and has an equivalent accuracy when corrected for temperature effects on the density of mercury and on scale distortion. The combined error is given by:
5
.491)2 2
(0.012}2
( 0.01.491 0.04 0.01 g2 (p)
+
+
\\ 2 /
2 2
/
\\
2 2
4.486 x 10-5 psi
=
2 0.3440 in H 0
=
2 c)
Estimate of 62(a p)
The water filled manometer is readable to within 0.02 inche' 'ater.
Considering that left and right legs of the manometer had to oe read gives:
2 2
6 (AP) 6 (I
)+62(1,gL)
=
2 (0.02/2)2 2 x 10-4 (inches water)2
=
=
d)
Estimate of 6 2 ( py)
All vapor pressure measurements were obtained with Foxboro type 2701 RPG DEWCELS connected through resistance-current converters and special RTD processing boards to the plant computer. We DEWCELS are certified to an accuracy of at least O.1% and the resulting system error will not exceed 0.2 - INCHES WATER vapor pressure. Therefore:
i=6 P
Pv wi yg
=
y i=1 i=6 2
6 (P ) =
y yyg g
(Pyi)
!=1 i=6 "vi i=1 Using the appropriate weighting factors:
2 2
6 (P ) =
- 1. 86 x 10'3 INCH H O y
2 1
1
1 3
e)
The overall measurement error is determined using the individual measurement variances and the following parameters oocained from the test data:
IS 0.2456 wt 7./ day
=
1564.34 inches water P,
=
T 6.41 inches water y
67 4.15 inches water
=
2 i
537.48 R
=
(67 +I)y)2" 2 6kT) 2
+
6 P) (L /P )2 6
(L) 100
=
3 o y
pot 2 hP ) (100/P )2
+ 2 6 (a P) (100/P )2
+
o y
o
- 1. 684 x 10-5
=
The 957 confidence interval for a single 24-hour data comparison becomes:
L 126 (L)
Li 0.0082 w t7./ day
=
And the 957. confidence interval for the average of 5 24-hour data comparisons becomes:
5 i 26 (L)
L 0.2456 1 0.0037 vt7./ day
=
V3 I
=
i I 3.
Comparison of Methods of Error Calculation 957. CONFIDENCE INTERVALS METil0D 1974 TEST 1975 TEST Instrumentation Error Analysis 0.2520 1 0.0033 0.2456 1 0,0037 T-Distribution Error Calculation 0.2520 1 0.0105 0.2456 1 0.0087
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NRC DISTRIBUTION ron PART 50 DOCKET MATERIAL CU***'
TO:
' HO*
Northern States Power Co.
V. Stello 3-16-76 Minneapolis, Minn.
DATE "8 C8'V' D L.0. Mayre 3-18-76 OLETTEa O NoToniz t o Paor
.NeuvroRM NUMBER OF COPitS RECEtvEo 3 ORIGIN AL
@yNC lag 3lp g g o Ocorv 40 DESC RIP T ION ENCLOSumt Ltr. trans the follasing.......
Supplement # 1 to Report of Containrent Building Integrated Leak Test...i...
/
f40 Cys. Received) m.
AC PLARI NAME:
Monticello 5D b-EU-ID
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SAFETY FOR ACTION /INFORMATION ENVIRO AFST6NEl) AD :
ASSIGNED AL :
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