ML17249A510

Design Analysis,Rcs Subcooling Margin Monitoring Sys Error Analysis.

ML17249A510
Person / Time
Site:	Ginna
Issue date:	01/23/1980
From:	Deinhardt C ROCHESTER GAS & ELECTRIC CORP.
To:
Shared Package
ML17249A509	List: ML17249A508 ML17249A510
References
EWR-2604, NUDOCS 8001280421
Download: ML17249A510 (18)

Text

Design Analysis RCS Sub Cooling Margin Monitoring System Error Analysis Rochester Gas and Electric Corporation 89 East Avertue Rochester, New York 14649 EWR 2604

'Revision 0

, January, 23, 1980 O

Prepared by:

r' P.c. 'i inc Ele

'ATE Engineer Reviewed by:

Manag Electrical Engineering ATE Approved by:

ATE Manager, Electrical Engineering Page i 2 8 00y880

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Revision Status Sheet Latest Latest Latest Pape Rev. Page Rev. Page Rev.

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0 Design Analysis Revision 0 EWR 2604 Page' "ii Date 42-91

Sub-Cooling Margin Monitoring System Error Analysis Puruose The purpose of this analysis is to compute the un-certainty in the value of RCS subcooled margin, as computed and displayed to the plant operator. This value of subcooling margin is computed by a Foxboro Spec 200 analog computer, utilizing as inputs RCS hot leg temperature and pressurizer pressure.

Referenced Documents A. Westinghouse bulletin 43-252D WE A B. Foxoboro Company Product Specification Sheets:

1. PSS 2C-2A1B 06-77

2. PSS 2C-2A1C 04-77

3. PSS 2C-2A1W 07-77 C. Letter dated 12/27/79 to Westinghouse Owner's Group Representatives from R. A. Newton of Wisconsin Electric Power Company D. Rosemount Engineering Company drawing 176JA, Rev. C dated 12/23/66.

E. "Signal Characterizer Calibration", Rev. 0, Foxboro Company.

F. RG&E drawing 21489-297, Rev. 0 G. RG&E drawings 21489-303, Rev. 1, and 21489-302, Rev. 1 H. 1967 ASME Steam Tables Letter dated 2/15/78 from J. D. Woodward W, to J. Arthur Foxboro Instruction Sheet 18-232 for 66B Current Repeater Com uter Pro rams A. "Curvfit" BASIC least squares polynomial curve fitting program.

B. "Rootr" BASIC cracsk polynomials.

DESIGN ANALYSIS REV 1

2604 PAGE of 1/23/80 EUUR No ~ DATE 42 ~ 60 REV ~ 2/77

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III I

IV". Assum tions A. Only the pressure transmitter (PT) and tempera-ture transmitters are located inside containment, and are therefore subject to the accident environ-ment. All other equipment is therefore assumed to be functioning under normal conditions of temperature, humidity, radiation, electrical voltage and frequency.

B. Reference D above, states that all material used in construction of the RTD's can withstand temperatures to 650'F. In 'addition leadwire resistance compensation is included in the resistance to voltage converter. Therefore, the accident environment has a negligible effect on the RTD, and conversion circuitry.

C. Errors due to calibration error are considered negligible, for the Foxboro Spec 200 equipment, since these units were factory calibrated, and have better accuracy than that stated in reference B. The calibration errors for the Foxboro 66BR are assumed to have a negligible effect on system accuracy.

D. Accuracy and repeatibility values are in terms of calibrated span, unless otherwise noted.

E. Accuracy and repeatibility errors are summed for conservatism.

V. A~nal sis A. This analysis utilizes some of the procedures outlined in reference C above.

B. Instrument accuracies (refer to attached diagram Sl).

1. Pressure transmitters (Foxboro EllGM) from ref. C. page B-2 Maximum normal instrument error =

)5(4) + 3 + i 2(8) = 14.7 psi Maximum instrument error under accident i

conditions = 68 psi, (from ref. I).

DESIGN ANALYSIS REV 2

2604 PAGE of 1/23/80 E)UR No ~ DATE 42 ~ 60 REV ~ 2/77

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2. Isolation amplifiers (Foxboro 66BR-OH) from ref.'J accuracy 2 0.5%, repeatability = 0.1%

i Total error = 0.6%

0.6% (2500-1700) = S ~4.8 si

3. Current to voltage converter (Foxboro Spec.

200 2AI-I2V) from ref. b accuracy = 2 0.25% repeatability < 0.1%

Total error = 2 .35%

.35% (2500-1700) = i ~2.8 si

4. Therefore the total normal error present. at the input 'of the function generator is:

(14.7) + (4.8) + (2.8) = 2 15.72 psi Under accident conditions total error =

15.72 + .68 = 2 83.72 psi This error in the pressure signal must now be transformed into equivalent error present. at the output of the function generator. To do this, the steam tables between 1700 psig and 2500 psig must be modeled. Using the "Curvfit" program and steam table data (ref. H) the follow-ing polynomial was developed:

= 1.4172591E-4 + .96584976 x P-6.1328799E-4 TSAT x P + 1.8916803E-7 x P -2.2256878E-11 x P maximum error = + .0291% in modeling the steam tables The first derivative of this equation may be used to compute the error in the saturation tempera-ture as a function of the error in the pressure signal, hence:

hTSAT (max) = 8P hP =

x f (Pm) t Pressure error Pm = 2000 psig (S.I. termination)

SAT 0P .96)84976-1.22657598$ -3xP+5.670409E-7xp -8.9027512E-11xp t

SAT = 83.72xf (2000 + 14.7) 5 87oF This would be the error in the output. of the function generator if: 1) the steam tables were modeled with no error, and 2) there were no inaccuracies in the function enerator.

DESIGN ANALYSIS REV 3

of ElUR No.'604 PAGE DATE 1/23/80 42 ~ 60 REV ~ 2/77

I l Reference E, defines the function that, was programmed into the function generator by Foxboro. To compare this curve with the steam tables, for the it is necessary to develop the polynomial steam tables adjusted for 'scaling, spanning and zeroing. This new function can then be used to compare the Foxboro calibration points with equivalent values from the steam tables.

The results of these computations are shown on p'ag 7.

The result of this computation shows that the maximum error is -2.24%, (note: all errors are negative and therefore conservative). This error also occurs at approximately 1710 psi and therefore will be used for conservatism.

error = -2.24% (669-614.3'F)

-1.23 F The error due to inaccuracies of the function generator are:

accuracy 2 0.5% repeatability = 0.25%

total error = i 0.75%

41 F (669-614.3'F)

The errors present are therefore a) t 5.87'F due to errors propagated by the pressure signal b) -1.23'F due to error in steam table modeling c) 2.41 F due to "electronic" drifting These errors are each generated by a separate random process, therefore, the total error at the output of the function generator is:

(5-87) + (1.23) + (.41) = 2 6.01 F

5. Temperature transmitter (RTD) (Rosemount 176JA) Reference D lists the accuracy as Tem erature 'F 32 .011 525 .055 625 .065 DESIGN ANALYSIS REV 2604 PAGE of 1/23/80 EVVR NQ. DATE 4R ~ 60 REV ~ i/77

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Repeatability .. 2'F or 1% of span whichever is greater error = .065 + 1.0% x (700-500) =+2.065'F

6. Resistance to voltage converter (Foxboro 2AI-P2V) from

'epeatability ref.

<0.1%

B, accuracy i .25%,

error = 2 .35% (700-500) 7 F Total error at input of summer from temperatur measurement.and conversion =

(2.065) + (.7) = 2.18 F

7. The signal present at summer inputs are 1 ) THOT

2) T SAT i2'6 2 18 F 01 F Since both these errors are generated by separate, random processes, the total error as a result of the summing function is (6.01) + (2.18) = t 6.39 F

8. The error introduced by the summer itself.

is:

accuracy 2 0.5%, repeatability < .25% (Ref. B) error = 2 .75% (100'F) 75oF

10. The error from the indicator (W V252) is accuracy 2 1.5%, readability 2 1/2 of division error = 1.5% (100-0'F) = 2 1.5'F (accuracy) 2oF error = e 1/2 division z drvzszon = i 1'F ll. The total process error is therefore the square root of the sum of the squares of the errors computed in sections 7,8,9, and 10 above Total system error =

(6.39) + (.75) + (1.5) + (1.0) = i 6.71 F DESIGN ANALYSIS REV 5

2604 PAGE of 1/23/80 EMlR NO. DATE 42 ~ 60 RKV. 2/77

4 VI. Conclusion From the foregoing analysis, the maximum error in the value of subcooling margin is 6.7'F.

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0 DESIGN ANALYSIS REV 6

2604 PAGE of 1/23/80 E'lUR No. DATE 42 ~ 60 REV, 2/77

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iX" Y FHA(X) FHA(X)-Y X ERROR 0 5.71 .58486 125135 24 0 1.25 6.11 5i9911195 -rii888052 -1<984279 215 6.48 6.3713626 .10863742 -i>7050892 3 75

~ 6i84 6i 7333361 - r 1066639 -1 r 5841167 5 7o19 7.0821079 -.10789215 "1.5234468 6r25 7i52 7i4200717 -9r9928261E-02 -ir346729 7.5 7o84 7.7469477 -9i3052297E-02

-io2011479 So75 Sol5 So0597818 -9.0218245E-02

-ioii93634 10 8i45 8>352946 -i09705404 -1.1619139 5.584865 5.584865 100 EHD AT 0120 4 LIST 0010 DIM A(50) 0020 DEF FHA(X)=5.584865ke338007394X-o011585362'4X"2fo0010028964X"3"o000045635274 4X"4 0030 DIM B(20)rC(20)rD<20) 0035 LET I=1 0040 PRINT 'TYPE IH Xr Y PAIRS' o i OrO TO INPUT A(I)rB(I) EHD'045 0050 IF B(I)=0 THEN GOTO 0100 0060 LET I=i%i 0070 GOTO 0045 100 PRINT 'X 'r'Y 'r'FHA(X)'r'FHA(X)-Y'r'I I

ERROR'110 FOR K=1 TO 0115 LET Y=FNA<A(K))

0117 PRIHT A(K) rB(K) r Yr Y-B(K) r((Y-B(K))IY)4100 0120 NEXT K 4 SAVE'COMPARE

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