ML20137F049

Forwards Addl Info Re SER Paragraph 6.3.5.2,Confirmatory Item 22 Re Small Break Loca,To Be Added to Response to Q440.56.Info Will Be Included in Amend 19 to FSAR

ML20137F049
Person / Time
Site:	Vogtle
Issue date:	08/21/1985
From:	Bailey J GEORGIA POWER CO.
To:	Adensam E, Adensam E Office of Nuclear Reactor Regulation
References
0053V, 53V, GN-688, NUDOCS 8508260134
Download: ML20137F049 (3)

Text

m Georgia Pow r Company floute 2, Box 299A

, , Waynssboro, Georgia 30830

• Telephone 404 554 9961 404 724-8114 Southern Company Services, Inc.

Post Office Box 2625 Birmingham, Alabama 35202 Telephone 205 870-6011 Vogtle Proj.ect August 21, 1985

' Director- of Nuclear Reactor Regulation File: X7BC35 Attention: Ms. Elinor G. Adensam, Chief Licensing Branch #4 Log: GN-688 Division of Licensing U.S. Nuclear Regulatory Commission Washington, D.C. 20555 NRC DOCKET NUMBERS 50-424 AND 50-425 CONSTRUCTION PERMIT NUMBERS CPPR-108 ' AND CPPR-109 V0GTIE ELECTRIC GENERATING PLANT - UNITS 1 AND 2 SER CONFIRMATORY ITEM 22: SMALL BREAK LOCA

Dear Mr. Denton:

Attached for your staff's review is additional information to be added to the VEGP response to Q440.56. This information addresses the concerns of SER paragraph 6.3.5.2, confirmatory Item 22 and will be included in Amendment 19 to the FSAR.

If your staff requires any additional information, please do not hesitate to contact'ne.

Sincerely, J. A. Bailey

~ Project Licensing Manager JAB /sm Attachment xc D. O. Foster G. Bockhold, Jr R. A. Thomas T. Johnson (W/o Att.)

J. E. Joiner, Esquire D. C. Teper (W/o Att.)

B. W. Churchill, Esquire L. Fowler M. A. Miller W. C. Ramsey B. Jones, Esquire (W/o Att.) Vogtle Project File L. T. Gucwa 0053V 0

0, 8508260134 850821 dg PDR ADOCK 0,5000424 g E PM

As k a VEGP-FSAR-Q C. Decrease in scale of accumulator water levels and decrease in pressure (a low water level alarm and low pressure alarm is provided for each accumulator).

D. Emergency core cooling system valve and pump position indication, status lights, and annunciators.

E. Flow from emergency core cooling system pumps.

For very small LOCAs (approximately less than 2-in. diameter) in which the containment high pressure setpoint may not be reached, the operator would observe the safety-related indications plus the first two normally available indications. In addition, a charging flow / letdown mismatch would provide the operator with another indication of leakage from the reactor coolant system.

Since the operator would observe the pressurizer level and receive additional indications that a LOCA occurred, a manual safety injection would be initiated immediately. As presented in WCAP-8356, the time to uncover the core following a small break is relatively long (e.g., greater than 10 min for a 2-in.

break). The operator would, therefore, have sufficient time to manually initiate safety injection.

Q. 446. 5 6 Aclch b n c.h aed) i Q440.56-2 Amend. 8 7/84 L

440.56 Addition Inadequate Core Cooling Analyses results are reported in WCAP-9753. These analyses were performed using the NOTRUMP computer code to model 1 inch and 4 inch cold leg breaks in a standard 4-loop plant. These are best estimate, full power analyses assuming feedwater available and no high pressure safety injection. Full power analyses bound transients during startup or shutdown conditions (see Section 6.3.3.5). For the cases in WCAP-9753 where no operator action is assumed, fuel clad temperatures do not reach 2200'F fo'r three hours in the 1 inch break and 27 minutes in the 4 inch break case. For a 2 inch break at Vogtle during startup or shutdown, pressurizer level will drop off scale and RCS pressure will decrease at least 200 psi within 2 to 3 minutes after break initiation. The operator has at least 20 minutes (a realistic estimate would be between 1 and 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />) to notice the decrease in RCS pressure or the loss of pressurizer level (since the operator has diverse indications to observe, since failure of an operator to ignore one indication would not preclude nanual SI initiation) and manually initiate safety injection. Based on simulator validation of the Westinghouse Emergency Response Guidelines, this is sufficient time for the operator to manually initiate safety injection.

It should also be noted that Vogtle Technical Specifications do not require the two centrifugal and one positive displacement charging pumps to be locked out during startup and shutdown. This reduces the chances of a LOCA occurring during startup or shutdown with no safety injection.

0524n/RJM/8-85 e