ML20086Q255
| ML20086Q255 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 07/01/1976 |
| From: | Stallings C VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | Moseley N NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| Shared Package | |
| ML20086Q236 | List: |
| References | |
| SR-S1-75-08, SR-S1-75-8, NUDOCS 8402270489 | |
| Download: ML20086Q255 (22) | |
Text
_ _ _ _ . _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ___
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SUPPLE!! ENTAL REPORT.
E SPECIAL REPORT _
SR-St-75-08_
SD1 MARY REPORT CONTAlta!ENT LEAK RATE TESTING DO3KET NO. 50-280_
LICENSE NO. DPR-32 JUNE 30, 1976 SURRY POWER STATION VIRGINIA ELECTRIC AND POWER COMPAfW B402270489 840707 gDRADOCK 05000280 PDR
- r
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~:_-________
Tlis report is subn ted to provide supplemental in cation to SR-Gl-75-08,
! Sumnary Report of Containment Leak Rate Testing. The following topics will be .
discussed:
- 1. Errors inherent in correlating Type A leakage tests with Type B and C tests.
- 2. Instrument error analysis.
I. Correlation of Type A, B and C Tests Proposed Appendix J to 10CFR50 dated August 27, 1971 and specified in Technical Specifications states that if repairs are necessary to meet the acceptance criteria of the Type "A" Test, the test need not be repeated provided local measured leakage reductions achieved by repairs reduce the containment's overall measured Icak rate to acet the acceptance criteria.
This ~ calculation is explained on pages 16-13 of SR-Sl-75-08. The results are repeated below with the addition of a corecction for instrument error in the Type "B" and "C" tests (5.4%). .
Correlation of data:
Integrated Leak Rate (1617 SCFil) * '
. /f, plus confidence band (60 SCFil) + 1677 SCFil Leakage reduction through SG tubes - 1232 SCFil Leahage reduction through containment isolation valves in systems connecting the cont, atmosphere - 38 SCFil with open systems outside the containment Leakage reduction thru containment isolation valves in systems connecting.the cont.: atmosphere - 796 SCFil with closed systems outside the containment.
Correction for instrument error in Type B and + 112 SCFil C Tests (5.4%)
- 277 .SCFil w + ,
a '.
( .
~
- I. I!!STRIDict!T ERROR Equ iptwn t Descriptions The dif ferential pressure between the reference bulbs and the containment atmosphere was measured with a 0-60 inch U-Tube manometer, Meriam Instrument Medel 20CB10. The fluid used was an oil uith a specific gravity of 1.04. Accur-acy was to 0.01 inches with repeatibility to 0.0025 inches of oil.
The absolute pressure of the containment atmosphere was measured with a 0-120 inch mercury manometer, Exactel Model 500. Digital readout and accuracy were to 0.001 inches of mercury with repeatibility to .00025 inches of mercury.
Containment temperature was measured with 18 RTD's, Electric Thermome.ter Inc.
Model P-B2155. Individual RTD accuracy was to 0.l*F. An additional error of-
.05*F is inherent in computer analog to digital conversion. Therefore accuracy is to 0.15'F with repeatibility - to 0.04*F.
Vapor pressurc. was determined using two deu cells, Foxboro Model 2711AG.
Accuracy, including computer error was to 0.55%, repeatibility to .14%. This corresponds to .05 in H2 O and .01 in H2 0, respectively.
The nakeup air flow meter used for verification was an American Meter Controls, Inc. Model AL2300 with an accuracy of 0.5%.
Instrument Error Analysis Both the reference and the absolute method of leakage determination require an hourly calculation of the mass of air in the containment. The leakage rate is then determined by a least squares fit of the calculated masses over a 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period. The uncertainty in the mass calculati;n for each method is estimated as follows.
~ L-_Y--~.__ _ - _ _ _
The apparent tive leakage is due to errorsA herent in this type of correlation which tend to give different results in Type "B" and "C" tests than the Icakage which existed at the tice of the Type .
"A" test. This error is due to the difficulty of duplicating during the Type "B" and "C" tests the exact conditions which existed at the tInc of the Type "A" test. Causes of this type of error include the following: *
- 1. For leakages through valves which connect the containment with closed systens outside, a significant back pressure may have existed during the Type "A" test which was not present for the "B" and "C" tests. This would yield higher results .
in the B and C tests than existed during the Type A test.
- 2. During the Type "A" test, the containment sump is flooded to simulate accident conditions. As a : result ,the leakage ,
=1- '
through.certhin valves is water leakage rather than air leakage. --
Type "B" and "C" tests are air leakage tests and thus tend to .
give higher leakage rates than existed during the Type "A" test. For this test, the outside recirculation spray pump suction valves (MOV-RS-155A & B) and the Lou Head Safety Injection Pump Suction Valves (MOV-1860 A&B) which have water leakage during the i
Type "A" test, were najor sources of leakage. The as found leakage test results for these valves were probably conservative contributing to the negative corrected leakage.
The above items are the major sources of error in the correlation of leakages from Type A, B and C tests'. Other sources include changes in seating due to valve cycling between tests, seating variations due to different pressurization rates between tests, and instrument error.
G
ser p u u _t; m umu , - - _ _ ----- -- - __ _____ ______________ _ __ _ _____
. ass calculation is by the fo la:
The reference meth 5
Q = Qo - 1.7558 x 10 (pD0 Pp) _ (Pyo _ Py) ~
L T -
WilERE: Q = quantity of air in containment at time, ti; lb cass.
Qg = quantity of air in containment at time, to; lb mass. .
P D
= m n meter differential pressure at time, ti; in 11 20.
P noneter dif ferential pressure at time, to; in 110. 2 90 Py = containment vapor pressure at time, ti; in 1120.
Py = containment vapor pressure at time, to; in H20.
T = average containment temperature at time, ti; 'R.
The change or uncertainty in Q due to uncertainties in the measured .
variables is given by: 2 a 2 7a a .5P o yla. 5PhdG.5 o Vo da.JVVd@.1N 3Q=1.7558x10 s
gp j p g(/ gy T j The formula as .umes that all errors are systematic rather than random ,
in nature. The error in Q after differentiating is: g I
4, . '- c, ..
903 . g. Po + 6% '
e 4 kPo;-Pol-(Pv,-Pd c = 1.7558 x 10 a A( / ~(T/ (T) t T/ ( Ta L hP p = JPD = ep p = ep *
- 0 2
D JVo = $V = ey 0 V= .05 in.1120 dT==eT= 15/ K = .035 R e
e e-9 9
O i
y
. : g? . .
Adg
Nining equivelanE ferU 2 2.
2 Do +2 EoV + f D -Pg4 Pv'e,a~ ya e = 1.7558 x ,
Q ,_. T/ (T/ i I~ ./ _
= 1.7559 x 10 5'g [.O 1
+ 2[(.05540/} , 28.423-20.020-4.244 / 44.187}0.035
~
,_ (510 54o e s4o 5 -10 ~8 ~12 '/2
- 1.7558 x 10 "(,.9810 + 1.7 x 10 + 1.0 x 10 eq= 23.4 lb mass' Absolute Method - uncertainty in mass calculation.
The absolute ucthod mass calculation is by the formula.
.- "a Q = 1.7558 x 10 5
Pa = 1.7558 x 105 (p_py)
T. T WilERE: Q = quantity of air in containment, lb mass.
Pa = c ntainment absolute pressure, in.1102 .
P = containment pressure, in 110 Pv = containment vapor pressure, in. II 20
- T = containment average tecperature, *R The change or uncertainity in Q due to uncertainties in the measured variables is given by: 3 2 2 -
s ,IJ G.5 P l + [c!& , S Py$ . / da .5T
$Q = 1.7558 x 10 dp ) (f pq )3 gp /,
The formula assumes that all errors are systematic rather than random in character. The error in Q after differentiating is:
a a ff aE
'ed 3 P-Pd eq= 1.7558 x 10 5(%+I-ev T iT3 ) e[/ _ .-
e = .001 "Ilg a.Ol3G H 2O p
cy= .05 " 11 0 e = .15*R + .035*R h
r -- - - . _ _ . _ _ _
- - _ _ 35cM
.* -' e = 1.7558 x 9
.0136 + .05 + 14 ,0-. 4.2 .035 i , ,
,( 540 j $ 5402 h5 540 / / ,
- F -10 -9 8' 1/2 .
5
= 1.7558 x 10 6. 3 x 10 + 8.5 x 10 + 3.2 x 10 _
1/2 5 . = 1.7558 x 10 {4.11x10 ,
c = 35.6.lb. mass ppcatibility Error Analysis Using the same formulas as above, the repeatibity error for the two methods is estimated as follows:
Reference method: -
- 2 fe e,i +2 a i 'Y2.
e = 1.7558 x 10 5
21 es,--
e
+
For Po- Pvo4 Pv GT.l)a
/
4 - ( T/ T s I /-
Instrument repeatibility ep = .0025 #11 2 0
e = .0100 11 0 .
2 cT = .007*R 5 N cQ = 1.7558 x 10 I[.002 2 W.2[.01 2.+ .
28.423-20.020-4.24h+4.187.007\2 (540 j- (540 540 x 540 s )[
5-q _11 _19 _y4 1/2
= 1.7558 x 10 4 + 6.9 x 10 + 4.0 x 10 L .3 x 10 .i 5 -5
= 1.7558 x 10 x 2.71' x 10 -
eq = 4.76 lb. mass.
Absolute method: 2. En W -
5 'feg,f+ f-ev ,/IP-Pvle)/-
Tf s T [ I* /
eq= 1.7558 x 10 f
. - nd,
// //
I = .0034 11 0 e" = .00025 )g 2 e = .01 , 11 0 O V 2 eT = .04 *R = .009 .'
h e = 1.7558 x 10 2, (.01 2
+ $1491-4.2 2~W Q f.0034
\540 j li45 l 540x540
- og b 6 ;
1/2
= 1.7558 x 10 3.61 x 10-11 + 3.00 x 10-10 + 2.11 x 10-9
' ~S "
= 1.7558 x 105 x 4.95 x 10 a 8.69 lb. nass.
Leakage rate error due to instrument error.
As shown on pages 6 and 7 of report SR-S1-75-08, the. Icakage rate is, -
determined by a least squares fit analysis of the hourly calculations of mass over the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> test period. The effects of systematic instrument error are '
diminished by this method of analysis rendering repeatibility error the prc5m-inent source of instrument uncertainty. The effects of errors in individual mass calculations on the overall leak rate may be estinated by the formula e = e n
EX* - (EX)2 .
N Uhere e = crror in slope in Ibm /hr D
For the reference method, the instrument repeatibility translates to an error in leakage rate as follows.
e = 4.76 m
EX'- (E )'
en = .132 lbm/hr.
e, = .0007wt%/2411r.
v .
.;G --
____2__
_ _ _ . _ _ _ _ _ _ _ _ _ . _ _ _ _ __ _ % 4 /- a s
~
Il . For the absolute ract( J. .
O O e = 8.69
' EX -(EX)'
_ t4 .
= .241 lb/hr
= .OOl2 'pt%/24 hr.
Type B and C tests are performed using rotameters of various ranges manufactured by the Brooks Instrument Co. All are accurate to + 5%. Flow pressure corrections are made based on a 0-50 psig Ashcroft pressure gage of + 2% accuracy. Commutation of these uncertainties yields an overall error of 5.4%.
e=[(.05)2+(.02)]f '
e = .054 .
In conclusion, a negative corrected leakage rate could be expected due to the errors inherent in correlating the Type A, B, and C tests as ,
discussed herein. A correcti~on for instrument error during the Type B and ,
C tests still yields a negative corrected leakage after repairs. It is
^
believed that the correlation between the Type A, L, and C tests remains valid and the measured Icakage reducti ns achieved by repairs have reduced the containment's overall measured Icak rate to acceptabic limits.
Se e
e d
, .-_____.__._.-_._m.
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Virginia Electric and Power Cc=pany l Docket IIo. 50-280 Surry Unit 1 License IIo. DPR-32 SPECIAL REPORT !!0:
SR-280/76-08 (Supplemental)
DISTRIBUTION:
Don Lanha:2, ADil ec With Enclosures Region II Docket Files 280 Region II Inspector with enclosures
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PDR COORDINATOR ONLY N' '#2
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Report sent to HQs and hold copies reproduced Date '
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- 2. Licensee Response to Enforcement Report
- 3. Licensee Response to IE Bulletins General Lice'nsee Correspondence
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- c. Document Date- - /- (( d. Date Received -
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and rhm srith this form along with acknowledgement letter dy i to the T'a coordinator. p . 4. , .
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Vi noi Er.ncinic Axo Pownie Co>tr y Itionwoxo,V norma nn:Gt m
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M July 1, 1976
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-REEN
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!!r. Norman C. Moseley, Director Scrial No.114 g Office of Inspection and Enforcement P0&M/ALH:jlf .g U. S. Nuc1 car Regulatory Contnission J Region II - Suite 818 Docket No. 50-280 -d 230 Peachtree Street, Northwest License No. DPR-32 -Q Atlanta, Georgia 30303 5
-sidI;i
Dear Mr. Moscicy:
a The Virginia Electric and Power Company hereby submits a copy of the supplemental report to Special Report SR-SI-75-08 entitled "Sunmary Report E Containment Leak Rate Testing" for Unit 1 dated June 30, 1976. 1 E
The substance of this report has been reviewed by the Station Nuclear _M Safety and Operating Committee and will be placed on the agenda for the next 9
-EE meeting of the System Nuclear Safety and Operating Conmittee. 9 Very truly yours, N ---
C '
I
$'.tk'h.@$4{6hro l 2 C. M. Stallings M Vice President-Power Supply 5
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and Production Operations @ 3 Enclosurc Y
cc: Mr. Robert W. Reid, Chief (40 copies) 3 Operating Reactors Branch 4 Q 9
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VINGINI A Ex.ucrarc Ann Powna COMPANY ..7.
H csaxoxo.Vanoux A 20201
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July 1, 1976
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w . .y Mr. Norman C. Moseley, Director Serial No.114 Office of Inspection and Enforcement P0&M/Alli:jlf U. S. Nucicar Regulatory Comission Region II - Suite 818 Docket No. 50-280 230 Peachtree Street, Northwest License No. DPR-32 Atlanta, Georgia 30303
Dear Mr. Moseley:
The Virginia Electric and Power Company hereby submits a copy of the supplemental report to Special Report SR-S1-75-08 entitled " Summary Report Containment Leak Rate Testing" for Unit 1 dated June 30, 1976.
The substance of this report has been reviewed by the Station Nuclear Safety and Operating Conunittee and will be placed on the agenda for the next meeting of the System Nuclear Safety and Operating Comittee.
Very truly yours,
. . fSN C. M. Stallings Vice President-Power Supply and Production Operations ~g Enclosure
.: Mr. Robert W. Reid, Chief (40 copies)
Operating Reactors Branch 4
()'D 5 COPY fENT REGIONz 7
i 4
- O o 1 SUPPLEMENTAL REPORT E
SPECIAL REPORT SR-S1 75-08 SIRetARY REPORT CONTAINMENT LEAK RATE TESTING DOCKET NO. 50 280 LICENSE NO. DPR-32 JUNE 30, 1976 SURRY POtJER STATION VIRGINIA ELECTRIC AND POtJER COMPANY
, , ei i
O O .
This report is submitted to provide suppicmental information to SR-Sl-75-08, Summary Report of Containment Leak Rate Testing. The following topics will be discussed:
- 1. Errors inherent in correlating Type A lehkage tests with Type B and C tests.
- 2. Instrument error analysis.
I. Correlation of Type A, B and C Tests ,
Proposed Appendix J to 10CFR50 dated August 27, 1971 and specified in Technical Specifications states that if repairs are necessary to meet the acceptance criteria of the Type "A" Test, the test need not be repeated provided local measured leakage reductions achieved by repairs reduce the containment's overall measured leak rate to meet the acceptance criteria. "
This calculation is explained on pages 16-18 of SR-Sl-75-08. The results are repeated below with the addition of a correction for instrument error in the Type "B" and "C" tests (5.4%). -
Correlation of data:
Integrated Leak Rate (1617 SCFH) *
.J/.'s plus confidence band (60 SCFH) + 1677 SCFH Leakage reduction through SG tubes -
1232 SCFH Leakage reduction through containment isolation valves in systems connecting the' cont. atmosphere - 38 SCFH with open systems outside the containment ,
Leakage reduction thru containment isolation valves in systems connecting the cont.vatmosphere -
796 SCFH with closed systems outside the containment.
Correction for instrument error in Type B and + 112 SCFH C Tests (5.4%)
- 277 .SCFH 9
.a. p g , e ggespe 6S ep - - % #' "* "
- N-**were=== =~ -
- e a que , .my, p g w ees., p,. g y seg e gnumie ge
(_ D- d 49 9 a tw *
- e w* -o w s ee - .oh4 e eeu= p e ese. = = _
4 O O
- The apparent negative leakage is due to errors inherent in this type of correlation which tend to give different results in Type "B" ,
and "C" tests than the Icakage which existed at the time of the Type.
"A" test. This error is due to the difficulty of duplicating during the Type "B" and "C" tests the exact conditions which existed at the time of the Type "A" test. Causes of this type of error include the following:
- 1. For leakages through valves which connect the containment with closed systems outside, a significant back pressure may have existed during the Type "A" test which was not present for the "B" and "C" tests. This would yield higher results in the B and C tests than existed during the Type A test.
- 2. During the Type "A" test, the containment sump is flooded to simulate accident conditions. As a : result ,the leakage _ ,
through.certain valves is water leakage rather than air leakage. - =--- .-
Type "B" and "C" tests are air leakage tests and thus tend to .
give higher leakage rates than existed during the Type "A" test. For this test, the outside recirculation spray pump suction valves (MOV-RS-ISSA & B) and the Low Head Safety Injection Pump Suction Valves (MOV-1860 A&B) which have water leakage during the Type "A" test, were major sources of leakage. The as found leakage test results for these valves were probably conservative contributing to the negative corrected leakage. ,
s The above items are the major. sources of error in the. correlation of Icakages from Type A, B and C tests'. Other sources include changes in seating due to valve cycling between tests, seating variations due to different pressurization rates between tests, and instrument error.
9 r r,. Y--
p
-3 .
O O II. INSTRUMENT ERROR Equipment Descriptions ,
The differential pressure between the reference bulbs and the containment atmosphere was measured with a 0-60 inch U-Tube manometer, Meriam Instrument ,
Model 20CB10. The fluid used was an oil with a specific gravity of 1.04. Accur-acy was to 0.01 inches with repeatibility to 0.0025 inches of oil.
The absolute pressure of the containment atmosphere was measured with a 0-120 inch mercury manometer, Exactel Model 500. Digital readout and accuracy
+ ,
were to 0.001 inches of mercury with repeatibility to .00025 inches of mercury.
Containment temperature was measured with 18 RTD's, Electric Thermometer Inc.
Model P-B2155. Individual RTD accuracy was to 0.l*F. An additional error of
.05'F is inherent in computer analog to digital conversion. Therefore accuracy is to 0.15'F with -repeatibility to 0.04*F.
Vapor pressure was determined using two dew cel.ls, Foxboro Model 2711AG.
Accuracy, including computer error was to 0.55%, repeatibility to .14%. This corresponds to .05 in 110 2 and .01 in H2 0, respectively.
The makeup air flow meter used for verification'was an American Meter Controls, Inc. Model AL2300 with an accuracy'of 0.5%.
l Instrument Error Analysis i t
Both the reference and the absolute method of leakage determination require -
\
an hourly calculation of the mass 'of air in the containment. ' The leakage rate is then determined by a least squares fit o'f the c'alculated masses over a 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period. The uncertainty in the mass ci.Y'eulation l for each method is estimated
\ b' as follows.
t g
-s . -]
d.
I
~ _ - _ _ _ - _ - _ _ _ . _ _ _ _ _ -
O O i Reference Method - uncertainty in mass calculation.
The reference method mr.ss cciculation is by the formula:
Q = Q, - 1.7558 x 10 PD 0_P)-(Pyo D _ Py i . T -
WilERE: Q = quantity of air in containment at time, ti; lb mass.
Q, = quantity of air in containment at time, to; lb mass.
P D
= manometer differential pressure at time, ti; in H20.
P = ma m ter differential pressure at time, to; in 110. 2 90 Py = containment vapor pressure at time, ti; in H20.
Py = containment vapor pressure at time, to; in 1120.
T = average containment temperature at time, ti; *R.
The change or uncertainty in Q due to uncer'..linties in the measured .
variables is given by: 2 2 2-La.5Po I[a.SPo IG.3 Vo fa.JVVda . -
3Q = 1.7558 x 1 5
dPo / jP, ) (dVo ) /V / 8 ._ [. .
The formula assumes that all errors are systematic rather than random in nature. The error in Q after differentiating is:
f eyi kPo:-Po')-(Pv,-Pv e w o
- o =
"' *
- t D/ (T)7ep[fe
.,,;iT '
?(/e f,LT[i T^ L hP p =
JPp = cpp = ep *
- 0 2
D JVo'=$V=cy0 =q= . . 20
.- 4 6
JT = e7 = .15/ [ = .035'R
,, su 4
S Yse v
e
, a' .._j
~5-O O Combining equivelant teras:
2 4 e = 1.7558 x 10 5
~ai (T/fepol .>T/ 2 jJlev.)E,l -Po,-Po- Pg Pv1 6 Tf- l
[g 8-4 I
)/
= 1.7559 x 10 5'2 [M + 2[.05_ } , 28.423-20.020-4.244 44187)g,333 (540/ \540s 5'4 o >< S40 / .
-so -8 -129 '/2
= 1.7558 x 10 5 "(,.9810 + 1.78 to + L.0 x 10 J
s eq= 23.4 lb mass' Absolute Method - uncertainty in mass calculation. .
The absolute method mass calculation is by the formula.
,, Sa Q = 1.7558 x 10 $
~
Pa = 1.7558 x 105 (p_py)
T T Wi!ERE: Q = quantity of air in containment, lb mass.
P, = containment absolute pressure, in. H 2O P = containment pressure, in H 2O Pv = containment vapor pressure, in. H O 2 T = containment average temperature, 'R The change or uncertainity in Q due to uncertainties in the measured variables is given by: 3 2 32 ., k SQ = 1.7558 x 10 5
,I(,jd a.5P'1)dda.
1, p La Py spy
/ + @IJA T /a .ST t
The formula assumes that all errors are systematic rcR- than random in character. The error in Q after. differentiating is:
2 2.
P-Pv e aE -
eq 5 4 +
= 1.7558 x 10
-l
- Hg =.Ol3G H O ##
t ep = .001 2 ey = .05 H0 e = .15'R + 035'R T
u
1
- 2 2 o = 1.75 x 10 0136 + f.05 + 1491.0 - 4.2 ) .035\
9 y ( 540 j 15403 540 x 540 / /,
~
5 I -10 -9 -8 1/2 .
= 1.7558 x 10 6.3 x 10 + 8.5 x 10 + 3.2 x 10 ,
~0
= 1.7558 x 10 5 {4.11x10 ,
e =
q 35.6.lb. mass Repeatibility Error Analysis Using the same formulas as above, the repeatibity error for the two methods is estimated as follows:
Reference method:
2 If2 Po,- Po - Pvo4 Pu Y7 e = 1.7538 x 10 q
5 2iT/ M +2 EV. T/+
)2 T / /_
Instrument repeatibility ep = .0025 ##'H 2O e = .0100 "H O ,
2 e
T = .007*R 5
eQ = 1.7558 x 10 I2 [.0025w.2[.01 2+[28.423-20.020-4.244+4.187.007 1
(540). (540 ( 540 x 540 s )J 5F -11 -10 -14 1/ 2
= 1.7558 x 10 4 + 6.9 x 10 + 4 ; 0 - 10 L . 3 x 10 .,
= 1.7558 x 105 x 2.71' x 10 eq= 4.76 lb. mass.
Absolute method: 2 2 9 4 5
eq= 1.7558 x 1
-(TfM +l-ev)I*b J T*/IlP-Pv)eT e
e e
+ ..
l O
Instrument rzpratibility O
ep= .00025 "lig0 = .0034 HO2 ey = .01 "H O l eT = .04 'R = .009 .
~
5 e = 1.7558 x 10 .0034 2+ 0132 + $1491-4.2 .00(
9 \ 540 4 540x540 546/
= 1.7558 x 105{3.61x10-11 + 3.00 x 10-10 + 2.11 x 10-9 1/2 L ~
5 ~
= 1.7558 x 10 x 4.95 x 10
= 8.69 lb. mass.
Leakage rate error due to instrument error.
As shown on pages 6 and 7 of report SR-S1-75-08, the Icakage rate is, -
determined by a least squares fit analysis of the hourly calculations of mass over the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> test period. The effects of systematic instrument error are ~
diminished by this method of analysis rendering repeatibility error the predom inent source of instrument uncertainty. The effects of errors in individual mass calculations on the overall leak rate may be estimated by the formula e, = e0 EX*' - (IX)
- N Where e ,= error in slope in Ibm /hr
~
For the reference method, the instrument repeatibility translates to an error in leakage rate as follows. ..
e = 4.76 m
f EX'- (EX)'
V N -
e ,= .132 lbm/hr. .,
e, = .0007wt%/24Hr. ,
e s9
~
.- O For tha cbcolute method.
O -
e = 8.69 m
IX -(EX)'
N :
= .24l Ib/hr
= .0012 ht%/24 hr. ]
l Type B and C tests are performed using rotameters of various ranges manufactured by the Brooks Instrument Co. All are accurate to i $%. Flow pressure corrections are made based on a 0-50 psig Ashcrofe pressure gage of i 2%. accuracy. Commutation of these ,
^
'! uncertainties yields an overall error of 5.4%.
i e=[(.05)2+(.02)]f .,
.q
,l e = .054 . -- -
1 In conclusion, a negative corrected leakage rate could be expected i i
due to the errors inherent in correlating the Type A, B, and C tests as [
discussed herein. A correcti~on for instrument error during the Type B and I C tests still yields a negative corrected Icakage after repairs. It is .',
j A
believed that the correlation between the Type A, B, and C tests remains valid and the measured leakage reductions achieved by repairs have reduced .
' J~
the containment's overall measured leak rate to acceptable limits.
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1
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