ML13331B083
| ML13331B083 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 11/07/1988 |
| From: | SOUTHERN CALIFORNIA EDISON CO. |
| To: | |
| Shared Package | |
| ML13331B082 | List: |
| References | |
| NUDOCS 8811150053 | |
| Download: ML13331B083 (4) | |
Text
ATTACHMENT 2 PROPOSED TECHNICAL SPECIFICATIONS P
3.3.2 SHUTDOWN STATUS APPLICABILITY:
Applies to piping connections between the feedwater condensate system and the reactor coolant system.
OBJECTIVE:
To preclude injection of feedwater condensate into the reactor coolant system when the reactor is shut down and to preclude the potential for overpressurization when water solid.
SPECIFICATION:
A. When reactor fuel assemblies are in the vessel and the reactor coolant pressure is less than 500 psig, two "positive barriers" shall be provided between the feedwater condensate system and the piping connections to the reactor coolant system. Additionally, when the reactor coolant system is water solid at less than 500 psig, two positive barriers shall be provided between the safety injection system and piping connections to the reactor coolant system. A "positive barrier" is defined as follows:
(1) Motor Operated Valves When closed and tagged with supply breakers open, except that power may be restored during no-flow tests of the safety injection system (Specification No. 4.2).
(2) Pneumatic/Hydraulic Operated Valves When closed and the condition tagged with the respective hydraulic block valve closed except that they may be opened during no-flow tests of the safety injection system (Specification No. 4.2).
(3) Manually Operated Valves When closed and condition tagged.
(4) Feedwater Pump (Overpressurization Protection Only)
When shutdown with the breaker in the racked out condition.
BASIS:
Under normal conditions, system operational interlocks assure that injection of feedwater condensate to the reactor by the safety injection system cannot occur.(1 ) These interlocks include:
- 1. Actuation of the safety injection relay which de energizes the condensate and heater drain pumps and closes the flow path for condensate, thereby preventing injection of feedwater into the coolant system.
- 2. Interlocks between the condensate isolation valves at the feedwater pump suction and the safety injection header isolation valves at the pump discharge which prevent the opening of the one valve unless the other is closed.
Below 500 psig the Safety Injection System may be removed from service. Below 400 psig the feedwater system may be removed from service. During these low pressure shutdown reactor coolant system conditions, the interlocks may be overridden for maintenance and/or to prevent intrusion of feedwater condensate or safety injection water into the reactor coolant system. Injection of feedwater has the potential to dilute the system and create a potential for a reactivity excursion. Injection of either safety injection water or feedwater, especially during water solid operations, creates the potential for pressurizing above limits established by 10 CFR 50 Appendix G and as reflected in Technical Specification 3.1.3.
The "two positive barriers" required by this specification provide protection of the Reactor Coolant System against boron dilution and overpressurization when in the low pressure and low temperature conditions. Two positive barriers are provided in each potential path between the Feedwater Condensate System, Safety Injection System and the RCS. During period of no-flow testing, an exception is provided on two of the positive barriers to allow the components involved in the test to perform their test functions while the remaining positive barriers (nos. 3 and 4) remain in effect.
Tagged, as used above, means tagged in accordance with current Southern California Edison Company procedures for tagging of equipment which must not be operated.
Reference:
(1) Final Engineering Report and Safety Analysis, Paragraph 5.1.
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- g.
Technical Specification 3.7, "Auxiliary Electrical Supply" BASIS:
The station is connected electrically to the Southern California Edison Company and San Diego Gas & Electric Company system via either of two physically independent high voltage transmission routes composed of four Southern California Edison Company high voltage lines and four San Diego Gas & Electric Company high voltage lines.
Of the four Southern California Edison Company lines, any one can serve as a source of power to the station auxiliaries at any time. Similarly, any of the four San Diego Gas &
Electric Company lines can serve as a source of power to the station auxiliaries at any time. By specifying one transmission line from each of the two physically independent high voltage transmission routes, redundancy of sources of auxiliary power for an orderly shutdown is provided.
Similarly, either transformer A or B, along with transformer C, provide redundancy of 4160 volt power to the auxiliary equipment, and in particular to the safety injection trains.
Correct operation of the safety injection system is assured by the operability of the load sequencers and the UPS for MOV 850C. Correct operation of the recirculation system is assured by the operability of the UPS for MOV 850C which also supplies MOV-358. In addition, each 4160 volt bus has an onsite diesel generator as backup.
In MODES 1, 2, 3 and 4, two diesel generators provide the necessary redundancy to protect against a failure of one of the diesel generator systems or in case one diesel generator system is taken out for maintenance, without requiring a reactor shutdown. This also eliminates the necessity for depending on one diesel generator to operate for extended periods without shutdown if it were required for post-accident conditions.
In MODES 5 and 6, the requirement for one source of offsite power and one diesel generator to be OPERABLE will provide diverse and redundant electrical power sources in order that the station can be maintained in the COLD SHUTDOWN or REFUELING condition for extended time periods. Additionally, this requirement will assure that operations involving core alterations or positive reactivity changes can be conducted safely.