ML19260D960

Responds to NRC 791227 Ltr Re Mod of Small Break LOCA Operator Guidelines.Facility Will Install Instrumentation & Readout Devices by 810101 to Ensure RCS Subcooling of 20 F. Auxiliary Feedwater Flow Will Be Restored to Min Level

ML19260D960
Person / Time
Site:	Beaver Valley
Issue date:	02/08/1980
From:	Dunn C DUQUESNE LIGHT CO.
To:	Schwencer A Office of Nuclear Reactor Regulation
References
NUDOCS 8002120672
Download: ML19260D960 (5)

Text

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'Af (412) 456-6000 435 Sixth Avenue P ttsburgh. Pennsylvania 15219 February 8, 1980 Director of Nuclear Reactor Regulation United States Nuclear Regulatory Commission Attn: A. Schwencer, Chief Operating Reactors Branch No. 1 Division of Operating Reactors Washington, D.C. 20555

Reference:

Beaver Valley Power Station, Unit No. 1 Docket No. 50-334 Primary System Subcooling Criterion for HPI Termination Gentlemen:

In response to your December 27, 1979 letter concerning modification of small-break loss-of-coolant accident operator guidelines, we have determined the calculated subcooling criterion for Beaver Valley Power Station does permit timely termination of high head safety injection for non-LOCA events. The errors and their sources used to develop the subcooling criterion and how the errors were combined are illustrated in the attachment to this letter.

For the long term solution of determining reactor coolant system subcooling, Beaver Valley Power Station will install, by January 1,1981, instrumentation and readout devices that will ensure 200F of actual subcooling.

A license condition imposed on the operation of Beaver Valley Power Station limits the secondary side water level rise rate in each steam generator to less than 1.2 inches per minute whenever the secondary side water level in a steam generator is below the level of the feedwater sparger. It is our understanding, based upon your letter of January 22,1980, that the NRC has reviewed the issue of the potential water hammer and a License Amendment will be issued to delete this license condition from the Beaver Valley Operating License prior to startup from the present shutdown. At that time, the auxiliary feedwater flow will be restored to the minimum flow required by the FSAR. This will ensure at least one steam generator is available as an RCS heat sink.

If you have quest _. .s concerning this response, please contact my office.

Very truly yours, 1951 307 Og G C. N. Dunn Vice President, Operations kDY s

S002120 *

. . t Beaver Valley Power Station, Unit No. 1 Docket No. 50-334 Primary System Criterion For HPI Termination Attachment - Page 1

1. Errors in' Indicated Pressure A. Normal Transmitter Reference Accuracy = 1 5% of span (Barton Model 763 Technical Manual) = 1 005 of 800 psi = 1 4 psi B. Combined accuracies of calibration = 1 135% of full range test equipment for transmitter (Fluke- = 1 00135 of 2500 psi DVM; Hiese pressure gauge; resistor) = 1 3.375 psi C. Allowed Calibration Tolerance = 1 5% of span (BVPS I & C Engineer) = 1 005 of 800 psi = 1 4 psi D. Ambient Temp. Effects on Transmitter = 1 5% of span (Barton Model 763 Technical Manual) = 1 005 of 800 psi = 1 4 psi E. Maximum Transmitter Drift = 1 1% of span (Barton Model 763 Technical Manual) = 1 01 of 800 psi = 1 8 psi F. Normal Instrument Accuracy = 1 5% of span (E Technical Mar.ual, Model 131-110 & = 1 005 of 800 psi E channel & overall accuracies manual) = 14 psi G. . Ambient Temp. Effects on Instrument = 1 1% of span (BVPS I & C Engineer; E Tech. Manual) = 1 01 of 800 psi = 1 8 psi H. Maximum Instrument Drift = 1 1% of span (BVPS I & C Engineer; E Tech. Manual) = 1 01 of 800 psi = 1 8 psi I. Normal Indicator Accuracy = 1 1.5% of span (E Technical '!anual 133-107) = 1 015 of 800 psi = 1 12 psi

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J. Maximum Indicator Reading Error = 1 1/4 of smallest meter divisicr (BVPS I & C Engineer) = 1 25 of 20 psi = 1 5 psi Maximum Normal Instrument Error = ! 4(4) + (3.375)2 + 3(8) + (12)2 + (5) = 1 20.89 psi Maximum Post-Accident Environment = 1 10% of Input Span Error for Transmitter (environment = 1 10 of 800 psi of = 280*F and 45 psig steam and less = 1 80 psi than 5 x 107 Rads of TID Gamma)

Barton ibdel 763 Tech. Shnual

., Maximum Total Pressure Instrument = Normal error + environment er c:

Error in Adverse Environment = 20.89 psi + 80 psi = 100.89 psi 1951 308

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Bea .i Valley Power Station, Unit No. 1 Docket No. 50-334 '

Primary System Criterion For HPI Termination Attachment - Page 2 II. Errors in Indicated Temperature - T e- ange nstament H

A. '1H Process Measurement Error = 13% of span (y setpoint study) = 1 03 of 600*F = 1 18'F B. RTD Reference Cal. Curve Accuracy = 1 39'F (Rosemont recal. of Sostman curves)

C. Accuracy of Calibration Test Equipment = 1 165% of span (I & C Foreman BVPS) = 1 00165 of 600*F = 1 99'F D. Allowed Calibration Accuracy = 1 25% of span (BVPS I & C Engineer) = 1 0025 of 600*F = 1 1.5'F E. Calibration Error Due to Non-Linearity = 1 3.5*F (BVT 1.4.3.1 data reduction)

F. Normal Instrument Accuracy = 1 25% of span (E Tech. Manual 111-118) = 1 0025 of 600*F = 1 1.5*F G. Ambient Temperature Effects on Instrument = 1 5% of span

-(E Tech. Manual 111-118) = 1 005 of 600*F = 1 3*F H. Maximum Instrument Drift = 1 1% of span (E Tech. Manual 111-118) = 1 01 of 600*F = 1 6*F I. Strip-Chart Recorder Error = 1 1% of span (E Tech. Manua! 133-101) = 1 01 of 600*F = 1 6*F J. Operator Readout Error on Recorder = 1 1/4 of smallest division (BVPS I & C Engineer) = 1/4 of 10*F = 2.5*F K. Digital Display Error => 1 1% of span (A to D error of computer) - 1 01 of 600*F = 1 6*F Maximum Normal ,, .,

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Temp. (T ) Err r =

H (18)' + (.39)' + (.99)' + 2(.. 5)2 + 2(6)2 +(3.5)2 + (2.5)'

+ (3)

.

= 1 20.7'F (strip chart recorder)

= 1 20.6*F (digital readout)

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Maximum Post-Accident = error equivalent to Environ = ental Error two junction boxes

= + .01% of 600*F

= 1 1*F

.'. Maximum Total Temperature (T H) = Normal error +

Error in Adverse Environment environment error

= 1 20.8'F (strip chart recorder)

= 1 20.7*F (digital readout) 1951 309

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Beaver Valley Power Statibn, Unit No. 1 Docket No. 50-334 Primary System Criterion For HPI Termination Attachment - Page 3 III. Errors in Indicated Temperature - Incore Thermocouples A. Thermocouple Reference Accuracy = 1 3*F B. Calibration Accuracy = 1 75% of reading (BVPS I & C Engineer) = 1 0075 of 600*F

= 1 4.5'F C. Analog-to-Digital Ins 2rument Accuracy = 1 1% of span

, (A to D error) = 1 01 of 600*F

= 1 6*F D. Maximum Instrument Drift = i 1% of span (BVPS I & C Engineer) = 1 01 of 600*F

= 1 6*F Maximum Normal Thermocouple Error = [(3) + (4.5)2 + 2(6)2

= 1 10.l*F Maximum Post-Accident = error equivalent to Environmental Error two junction boxes

= 1 01% of 600*F

= 1 .l*F

,. Maximum Total Tharmocouple = Normal error + environment Temperature Error in error Adverse Environment = + 10.1*F + 0.l*F

!

= 1 10.2*F s

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Beaver Valley Power Station, Unit No. 1

, Docket No. 50-334. '

Primary System Criterion For HP1 Terminarion Attach =ent - Page 4 IV. Calculation of Subcooling Margin After Consideration of Instrument Errors A. Under Adverse Environmental Conditions (LOCA and Steam Line Break Inside Containment)

Assume: Indicated pressurizer pressure = 2000 psig Minimum absolute pressure = indicated pressure -

maximum error

= 2015 psia - 101 psi

= 1914 psia

'

TSAT(1914 psia) = 629.8'F Indicated temperature to ensure =Tgg (minimum pressure) - max.

subcooling at minimum pressure temperature error

= 629.8'F - 20.8*F

= 609.0*F (T -strip chart recorder

= 609.J"F (T -digital readout)

= 619.6*F (Thermocouple)

The indicated subcooling =T

'

iN[ca(indicatedpressure)-

ted te=perature

= 636.9'F - 609.0*F

= 27.9'F (T -strip chart recorde:

=

H 27.8"F (T -digital readout)

= 17.3*F (Thermocouple)

B. Under Normal Environmental Conditions Assume: Indicated pressurizer pressure = 2000 psig Hinimum absolute pressure = indicated pressure -

maximum normal error

= 2015 psia - 21 psi

= 1994 psia TSAT (1994 psia) = 635.5'F Indicated temperature to ensure =T3g (minimum pressure)

.

subcooling at minimum pressure - max. normal temp. error

= 635.5'F - 20.7*F

= 514.8'F (T -strip chart recorde:

H

= 614.9'F (T -digital readout)

=625.4*F(TNermocouple)

The indicated subcooling = T (indicated pressure) -

indica $hdtemperature

= 636.9'F - 614.8*F

= 22.1*F (T -strip chart recorder H

= 22.0*F (T -digital readout)

=11.5'F(TNermocouple)

NOTE: The required subcooling in the emergency procedure must be at least as much as the calculated indicated subcooling.

\95\ W

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