ML20128K182
| ML20128K182 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 02/10/1993 |
| From: | SOUTH CAROLINA ELECTRIC & GAS CO. |
| To: | |
| Shared Package | |
| ML20128K168 | List: |
| References | |
| NUDOCS 9302180094 | |
| Download: ML20128K182 (2) | |
Text
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3/4.7 PLANT SYSTEMS BASES 3/4.7.1 TURBINE CYCLE 3/4.7.1.1 SAFETY VALVES The OPERABILITY of the main steam line tele safety valves ensures that the secondary system pressure will be limited to within 110% (1305 psig) of its design pressure of 1185 psig during the most severe anticipated system operational transient.
The maximum relieving capacity is associated with a turbine trip from 100% RATED THERMAL POWER coincident with an assumed loss of condenser heat sink (i.e., no steam bypass to the condenser).
The specified valve lift settings and relieving capacities are in accord-ance with the requirements of h etion III of the ASME Boiler and Pressure Code, 1971 Edition. The total relieving capacity for all valves on all of the steam lines is 13.76 x 106 lbs/hr which is 110 percent of the total se andary steam flow of 12.2 x 106 lbs/hr at 100% RATED THERMAL POWER. A minimum of 2 OPERABLE safety valves per steam generator ensures that sufficient relieving capacity is available for the allowable THERMAL POWER restriction in Table 3.7-1.
l STARTUP and/or POWER OPERATION is allowable with safety valves inoperable within the limitations of the ACTION requirements on the basis of the reduction in tecondary system steam flow and THERMAL POWER required by the reduced reactor trip settings of the Power Range Neutron Flux channels. The reactor trip setpoint reductions arc derived on the following bases:
For 3 loop operation (X) - (Y)(V)
SP =
X X 109 Where:
SP = Reduced reactor trip setpoint in percent of RATED THERMAL POWER V = Maximum number of inoperable safety valves per steam line 109 = Power Range Neutron Flux High Trip Setpoint for 3 loop operation.
X = Total rel?aving capacity of all safety valves per steam line in Ibs/ hour.
Y = Maximum relieving capacity of any one safety valve in lbs/ hour.
l SUMMER - UNIT 1 B 3/4 7-1 Amendment No.
hS Do P
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'PL' ANT SYSTEMS BASES 3 /4. 7.1. 2' EMERGENCY FEEDWATER SYSTEM The OPERABILITY of the emergency feedwater system ensules that the
. Reactor Coolant-System can be cooled down to less than 350'F from normal-operating conditions in the event of a~ total loss of off-site power.-
The emergency feedwater 3ystem is capable of delivering a total.feedwater~
flow of 380 gpm at a pressure of 1211 psig to the entrance of at;least two steam generators while allowing for (1) any spillage through the design--
worst-casebreakoftheemergencyfeedwaterline,(2)thedesignworst-case single failure, and-(3) recirculation flow. This capacity is-sufficient ~to ensure that adequate fe0dwater flow is available-to remove decay heat and reduce the Reactor Coolant System temperature to less than 350*F at which-point the Residual Heat Removal System may be placed into operation.
3/4.7.1.3 CONDENSATE STORAGE TANK The OPERABILITY of'the condensate storage tank with the minimum water volume ensures that sufficient water is available to maintain the RCS at HOT STANDBY conditions for 11 hours1.273148e-4 days <br />0.00306 hours <br />1.818783e-5 weeks <br />4.1855e-6 months <br /> with steam discharge to the atmosphere con-current with total loss of offsite power. The contained water volume limit includes an allowance for water not usable because of~ tank discharge line location or other physical characteristics.
3/4.7.1.4 ACTIVITY t-l The limitations-on secondary system specific activity ensure that the L
resultant offsite radiation dose will be limited to a small fraction of 10:CFR-Part-100 limits-in'the event of a steam line rupture..This dose-also-includes-l-
the effects _of.a coincident 1.0 GPM primary to secondary-tube leak in the L
steam generator of the affected steam line. These values 'are consistent;with1 the assumptions used in the accident analyses.
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i SUMMER
= UNIT.l
- B 3/4 7-2:
Amendment No..
J
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