ML17326A487

Forwards Response to Concerns Re Small Break LOCA Operator Guidelines Contained in NRC 791227 Ltr.Normal Fuel Power Subcooling Value Is Being Replaced w/45 F margin.Non-LOCA Transients & Emergency Operating Instructions Under Review

ML17326A487
Person / Time
Site:	Cook
Issue date:	01/30/1980
From:	Dolan J INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG
To:	Harold Denton Office of Nuclear Reactor Regulation
References
AEP:NRC:00346, AEP:NRC:346, NUDOCS 8002060557
Download: ML17326A487 (13)

Text

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ACCESSIUN 48R;8002060557 DOG ~ DATE: 80/01/30 NU fAHIZED: NO DOCKET FACIL:5 5 Donald G ~ Cook Nuc I ear Power Pl anti Uni t li Indiana & 05000315 0 3 6 Donald C ~ Cook Nuclear l ower Pianti Unit Zr Indiana & 05000316 AU MD NAMk AU [HUH AFFILIATION DULA P ~ ~ ~ Indiana & Michigan Electric Co ~

HEC IP ~ NAIVE H tc lP I EN T AFF I LJA r I ori OEN TOi4r M ~ R ~ Office of Nuclear Reactor Regulation SUBJECI: Forwards response to concerns re small oreak LOCA operator guidelines contained in NHC 791227 ltr TVormal fuel power ~

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4' INDIANA I, MICHIGAN ELECTRIC COMPANY P. O. BOX 18 BOWLING GR E EN STATION NEW YORK, N. Y. 10004 January30, 1980 AEP: NRC: 00346 Donald C. Cook Nuclear Plant Unit Nos. 'l and 2 Docket Nos. 50-315 and 50-3'i6 License Nos. DPR-58 and DPR-74

Subject:

Modification of Small Break LOCA Operator Guidelines Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Comission Washington, D. C. 20555

Dear Mr. Denton:

This letter and its attachment are our response to the concerns on small break LOCA operator guidelines expressed in the letter of December 27, 1979 which Mr. D. F. Ross addressed to the Chairman of the Westinghouse Owners'roup, Mr. C. Reed.

As a result of our analysis of subcooling criteria for the termination of safety injection, we are replacing our original value of 50oF, which is the nominal full power subcooling for both Cook Units, w1th a criteria of 45 F margin if if loop RTD's are used for temperature measurement or of 33 F margin core exit thermocouples are used for temperature measurements. The basis for this revised limit is discussed in Attachment A to this letter. Also, the non-LOCA transients and their associated Emergency Operating Instructions (EOI's) are being reviewed for the purpose of incorporating a subcooling criteria in the HPI ter-mination criteria. These reviews wi 11 be completed and the results transmitted to the NRC by the Westinghouse Owners'roup Chairman within the 21-day requirement stated in Mr. Ross'etter.

Very truly yours, JED:em John E: Dolan Vice President cc: R. C. Callen G. Charnoff R. S. Hunter R. W. Jurgensen D. V. Shaller - Bridgman 8002060

Mr. H. R. Denton, Director AEP:NRC 00346 bc: S. J. Milioti/J. I. Castresana/K. J. Vehstedt/V. P. Manno/J. G. DelPercio R. F. Hering/S. H. Steinhart/J. A. Kobyra R. F. Kroeger H. N. Scherer, Jr./S. H. Horowitz/J . M. Intrabartola E. A. Smarrella/V. VanderBurg - Bridgman R. S. Lease/L. Smith - Bridgman D. Wigginton - NRC Cook Plant Resident NRC Inspector J. F. Stietzel - Bridgman DC-N-6015.1 DC-N-6362.15 AEP:NRC:00346

ATTACHNENT A TO AEP:NRC:00346

Calculation of Subcooling Margin After Consideration of Instrumerit Uncertainties PRODAC Pressure Instr umentati on

1) RCS l<ide Ran e - Barton Model No. 763 Transmitter A. Normal 0 eration Channel statistical analysis + 2.41% of span (1)

PRODAC error + 0.005K of span (3)

Maximum normal error = (2.41 ) + (0.005) = 2.41% of span B. Post Accident Environmental allowance + 10.00K of span (4)

C. Maximum Total Error = 2.41 + 10 .00 = 12.41K of span Span = 3000 psia Maximum total pressure error 0.1241 x 3000

'372 ~ 3 psl II. Tem erature Instrumentation

1) Core Thermocou les A. Normal 0 eration Reference accuracy + 0 .12K of span (5)

Calibration accuracy + 0.185 of span (6)

PRODAC error + 0.005K of span (3)

Maximum normal error = (0.12) + (0.18) + (0.005) 0.22$ of span B. Post Accident Environmental allowance + 0.01K of span (7)

C. Maximum total error = 0.22 + 0.01 = 0.23Ã of span Maximum total temperature error = 0.0023 x 2500 5.8oF

2) RTD's Rosemount Inc. Model No. 176 KS A. Normal 0 eration Channel statistical allowance + 2.72K of span (1) error + 0.005% of PRODAC span (3)

Maximum normal error = J(2.72) + (0.005) = 2.725 of span B. Post Accident Environmental allowance 0.01% of span (7)

C. Maximum Total Error = 2.72 + 0.01 = 2.73K of'pan Span = 700oF Maximum total temperature error = 0.0273 x 700 19.1oF III. Calculation of Mar in Assume indicated pressure is 2250 psia. TSAT (2250) = 652.7 F Minimum pressure = 2250 - 372.3 = 1877.7 psia (1877.7) = 629.9 F TSAT Indicated temperature to insure subcooling =

TSAT (1877.7) - maximum temperature error

= 626.9 - 5.8 (thermocouples) 19.1 (RTD's)

= 621.1 F (thermocouples) 607.8 F (RTD's)

Indicated subcooling =

TSAT (2250 ) indicated temperature to insure .subcooling

= 652.7 - 621.1 (thermocouples) 607.8 (RTD's)

= 31.6 F (thermocouples) 44.9oF (RTD's)

Therefore, required subcooling margin = 32 F (thermocouples) 45oF (RTD's)

Calculation of Subcooling Margin After Consideration of Instrument Uncertainties Subcoolin Meter Pressure Instrumentation

1) RCS Wide Ran e - Barton Model No. 763 Transmitter A. Normal 0 eration Channel statistical allowance + 2.41% of span (1)

Rack error allowance + 0.255 of span (2)

Indicator reading error 0.105 of span (3)

Maximum normal error = (2.41) + (0.25) +(,.10) = 2.42K of span B. Post Accident Environmental allowance 105 of span (4)

C. Maximum Total Error = 2.42 + 10.00 = 12.425 of span Span = 3000 psia Maximum total pressure error = 0.1242 x 3000 372.6 psi II. Tem erature Instrumentation

1) Core Thermocou les A. Normal 0 eration Reference accuracy + 0.25 of span (5)

Calibration accuracy + 0.3Ã of span (6)

Rack error allowance 0.25K of span (2)

Indicator reading error 0.10% of span (3)

Maximum normal error (0.2) + (0.3) + (0.25) + (0.10) 0.45% of span

B. Post Accident Environmental allowance + 0.01% of span (7)

C. Maximum Total Error = 0.45 + 0.01 = 0.46$ of span Span = 1500oF Maximum total temperature error = 0.0046 x 1500 6.9 F

2) RTD's - Rosemount Inc. Model No. 176 KS A. Normal 0 eration Channel statistical allowance + 2.72K of span (1)

Rack error allowance + 0.25% of span (2)

Indicator reading error + 0.10Ã of span (2)

Maximum normal error = (2.72) + (0.25) + (0.10) 2.73K of span B. Post Accident Environmental allowance 0.01% of span (7)

C. Maximum Total Error = 2.73 + 0.01 = 2.74$ of span Span = 700oF Maximum total temperature error = 0.0274 x 700 19.2oF III. Calculation of Mar in Assume indicated pressure is 2250 psia. TSAT (2250) = 652.7oF.

Minimum pressure = 2250 - 372.6 = 1877.4 psia (1877.4) = 626.9 F TSAT

Indicated temperature to insure subcooling =

TS<T (1877.4) - maximum temperature error 629.9 - 6.9 (thermocouples) 19.2 (RTD's) 620.0 F (thermocouples) 607.7 F (RTD's)

Indicated subcooling =

TSAT (2250) - indicated temperature to insure subcooling 652.7 - 620.0 (thermocouples) 607.7 (RTD's)

= 32.7 F (thermocouples) 45.0oF (RTD's)

Therefore, required indicated subcooling margin = 33 F (thermocouples)

= 45oF (RTD's)

REFERENCES

l. Attachment to AEP:NRC:00040 entitled, "Westinghouse Reactor Protection System/Engineered Safety Features Actuation System Setpoint Methodology, " Table 3-4.

2. Moore Industries Data Sheets 164-710-01A and 142-710-01B (November 1977)

3. Conservative estimate

4. Attachment to AEP:NRC:00095; Westinghouse Letter NS-TMA-1950 and enclosed report entitled, "gualification Testing of Barton Transmitters."

5. Based on 3 F

6. Based on 0.75K of reading 8 600 F

7. TMI-OG-132

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