ML20116K014
| ML20116K014 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 08/08/1996 |
| From: | Cruse C BALTIMORE GAS & ELECTRIC CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9608140190 | |
| Download: ML20116K014 (3) | |
Text
_ ____ ________ -
CuanLEs II. OnesE Baltimore Gas and Electric Company Vice President Calvert Cliffs Nuclear Power Plant Nuclear Er.ergy 1650 Calvert Cliffs Parkway Lusby, Maryland 20657 410 495-4455
(
August 8,1996 U. S. Nuclear Regulatory Commission Washington, DC 20555 ATTENTION:
Document Control Desk
SUBJECT:
Calvert Cliffs Nuclear Power Plant Unit Nos.1 & 2; Docket Nos. 50-317 & 50-318 Editorial Correction to Page 6.3-5 of the Updated Final Safety Analysis Report
REFERENCE:
(a)
Letter from Mr. R. E. Denton (BGE) to NRC Document Control Desk, Updated Final Safety Analysis Report, Revision 17, dated November 18,1994 The attached page from our Updated Final Safety Analysis Report supersedes the page provided in Reference (a). The revised page contains text which did not print due to a word-processing error.
Please replace page 6.3-5 in your copies of the Updated Final Safety Analysis Report with the revised page. Eleven copies have been provided for your convenience.
Should you have questions regarding this matter, we will be pleased to discuss them with you.
Very truly yours, 2
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Attachment:
As Stated
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9608140190 960008 ADOCK0500g7 PDR K
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Document Control Desk August 8,1996 Page 2 cc:
(Without Attachment)
D. A. Brune, Esquire T. T. Martin, NRC J. E. Silberg, Esquire Resident Inspector,NRC Director, Project Directorate 1-1, NRC R. I. McLean, DNR A. W. Dromerick, NRC J.11. Walter, PSC J
4 I
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verify that the valve has functioned properly.
Upon verification that O
the vaive hes functioned ProPeriy. the ePereter wiii return the veive to its original position and test the remaining channel in the same manner.
The minimum time at which switchover to the recirculation mode could be required is 36 minutes.
This period is based upon operation of all three high-pressure
- pumps, both low-pressure
- pumps, and the containment spray pumps, all operating at design capacity.
The system is designed to keep the core covered following initial SI.
One high-pressure pump has sufficient capacity with complete spillage of the maximum flow leg to maintain core water level at the start of recirculation.
The automatic recirculation signal shuts down the LPSI pumps, sends an open signal to both recirculation line isolation valves, and a close signal to the minimum flow line isolation valves to signal isolation of the RWT.
However, the minimum flow valves are normally locked out in the open position in the Control Room to prevent possible SI pump damage.
The Control Room Valve handswitch is actually locked out. The lock-out switch is turned to ON when the RWT reaches a low level before RAS, allowing the valves to automatically close on RAS.
The Q
HPSI pumps continue to operate to provide core cooling water.
A key-operated manual override of the RAS contact in the LPSI pumps is installed to allow the LPSI pumps to run regardless of RWT level during long-term cooling.
In the recirculation mode, the HPSI pumps take suction directly from the containment sump.
At the discretion of the operator, a portion of the cooled water from the Containment Spray System may be diverted to the suction of the HPSI pumps.
The spray diversion valves are not powered from the diesel generators and therefore are not available on loss of offsite power.
This is a preferred method of operation and provides additional cooling and NPSH, but is not necessary to meet core cooling requirements.
The containment spray pumps are centrifugal pumps which discharge at the design flow rate against containment design pressure and system losses.
When the system is switched over to the recirculation mode of O
CALVERT CLIFFS UFSAR 6.3-5 Rev. 17
)
operation, the pumps take suction from the Containment Building and g
therefore do not have to pump against the pressure in the containment.
W The reduced pumping requirements during recirculation cause the pump to operate at a higher capacity thus providing more spray flow.
This excess spray flow can be diverted to the suction of the HPSI pumps without compromising the Containment Spray Systems effectiveness.
The design of the suction piping in the SI system conservatively assumes that the recirculated fluid is saturated at containment pressure and temperature conditions, therefore subcooled fluid at the SI pump inlet is not needed to meet NPSH requirements.
However, in the unlikely event of cavitation in the SI pump, the operator could divert a portion of the Containment Spray System water to the suction of the SI system pumps if offsite power is available.
The operator can monitor the SI pumps for cavitation by observing SI system flow meters, pump ammeters, and pressure gauges for decreased and erratic readings.
The LPSI pumps are also used to supply coolant flow to remove heat from the reactor following reactor shutdown and to maintain a suitable temperature for refueling and maintenance operations.
In this mode the system is designed to cool the RCS from 300 F to 130 F.
The g
maximum coolant pressure during this cooldown is approximately 300 psig.
6.3.2 SYSTEM COMPONENTS 6.3.2.1 Hiah-Pressure Safety In.iection Pumos The HPSI pumps are sized to ensure that one high-pressure pump will keep the core covered at the start of recirculation, assuming complete spillage of the maximum flow leg.
The requirements for boron injection for the steam line break and the injection requirements for smaller break sizes are also considered in the sizing. The high-pressure pumps are designed for the thermal transient conditions of 40 F to 300 F in 5 to 10 seconds and 300 F to 40 F in 5 to 10 seconds.
O CALVERT CLIFFS UFSAR 6.3-6 Rev.17l t