ML18153C268

Proposed Tech Specs Re Containment Vacuum Sys

ML18153C268
Person / Time
Site:	Surry
Issue date:	06/26/1990
From:	VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:
Shared Package
ML18153C267	List: ML18153C266 ML18153C268
References
NUDOCS 9007020147
Download: ML18153C268 (7)

Text

ATTACHMENT 1 PROPOSED TECHNICAL SPECIFICATION CHANGES

e TS ii TECHNICAL SPECIFICATION TABLE OF CONTENTS SECTION 3.15 DELETED 3.16 EMERGENCY POWER SYSTEM TS 3.16-1 3.17 LOOP STOP VALVE OPERATION TS 3.17-1 3.18 MOVABLE INCORE INSTRUMENTATION TS 3.18-1 3.19 MAIN CONTROL ROOM BOTILED AIR SYSTEM TS 3.19-1 3.20 SHOCK SUPPRESSORS (SNUBBERS) TS 3.20-1 3.21 FIRE PROTECTION FEATURES TS 3.21-1 3.22 AUXILIARY VENTILATION EXHAUST FILTER TRAINS TS 3.22-1 3.23 CONTROL AND RELAY ROOM VENTILATION SUPPLY FILTER TRAINS TS 3.23-1 4.0 SURVEILLANCE REQUIREMENTS TS 4.0-1 4.1 OPERATIONAL SAFETY REVIEW TS 4.1-1 4.2 AUGMENTED INSPECTIONS TS 4.2-1 4.3 ASME CODE CLASS 1, 2, AND 3 SYSTEM PRESSURE TESTS TS 4.3-1 4.4 CONTAINMENT TESTS TS 4.4-1 4.5 SPRAY SYSTEMS TESTS TS 4.5-1 4.6 EMERGENCY POWER SYSTEM PERIODIC TESTING TS 4.6-1 4.7 MAIN STEAM LINE TRIP VALVE TS 4.7-1 4.8 AUXILIARY FEEDWATER SYSTEM TS 4.8-1 4.9 EFFLUENT SAMPLING AND RADIATION MONITORING SYSTEM TS 4.9-1 4.10 REACTIVITY ANOMALIES TS 4.10-1 4.11 SAFETY INJECTION SYSTEM TESTS TS4.11-1 4.12 VENTILATION FILTER TESTS TS 4.12-1 4.13 DELETED 4.14 DELETED

e TS 3.8-2

6. Positive reactivity changes shall not be made by rod drive motion or boron dilution unless the containment integrity is intact.

7. The containment isolation valves shall be listed in Tables 3.8-1 and 3.8-2.

B. Internal Pressure

1. If the internal air partial pressure rises to a point 0.25 psi above the allowable value of the air partial pressure (TS Fig. 3.8-1 ), the reactor shall be brought to hot shutdown within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. I

2. If the leakage condition cannot be corrected without violating the containment integrity or if the internal partial pressure continues to rise, the reactor shall be brought to cold shutdown within the next 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

3. If the internal pressure falls below 8.25 psia the reactor shall be placed in hot shutdown within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in cold shutdown within the next 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

4. If the air partial pressure cannot be maintained greater than or equal to 9.0 psia, the reactor shall be brought to hot shutdown within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.

The Reactor Coolant System temperature and pressure being below 350°F and 450 psig, respectively, ensures that no significant amount of flashing steam will be formed and hence that there would be no significant pressure buildup in the containment if there is a loss-of-coolant accident.

e e TS 3.8-4 If the containment air partial pressure rises to a point 0.25 psi above the allowable value, the reactor shall be brought to the hot shutdown condition. If a LOCA occurs at the time the containment air partial pressure is 0.25 psi above the allowable value, the maximum containment pressure will be less than 45 psig, the containment will depressurize in less than 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />, and the maximum subatmospheric peak pressure wiU be less than 0.0 psig.

If the containment air partial pressure cannot be maintained greater than or equal to 9.0 psia, the reactor shall be brought to the hot shutdown condition. The shell and dome plate liner of the containment are capable of withstanding an internal pressure as low as 3 psia, and the bottom mat liner is capable of withstanding an internal pressure as low as 8 psia.

References FSAR Section 4.3.2 Reactor Coolant Pump FSAR Section 5.2 Containment Isolation FSAR Section 5.2.1 Design Bases FSAR Section 5.5.2 Isolation Design FSAR Section 6.3.2 Containment Vacuum System

ATTACHMENT 2 DISCUSSION AND SIGNIFICANT HAZARDS CONSIDERATION EVALUATION

e e Discussion The Containment Vacuum System is designed for the evacuation of the containment from atmospheric pressure to the subatmospheric pressure used for normal operation, for the removal of air to compensate for containment inleakage during normal operation, and for the removal of steam and air from the containment to compensate for in-leakage during long-term accident conditions. Operation of the containment vacuum pumps is seldom needed during normal conditions, and, in accordance with the original accident analyses, would not be required for several months after a design-basis accident.

Initially, the Containment Vacuum System, through the use of the steam ejector, is designed to reduce the containment pressure from atmospheric pressure to subatmospheric pressure in approximately four hours. In this capacity, the Containment Vacuum System is used to prepare the containment for plant startup and operation, and performs no safety-related function. During normal operation, the mechanical vacuum pumps are used to maintain the containment at a subatmospheric pressure as required ,by Technical Specification 3.8. Since the Containment Vacuum System is not part of the primary success path for mitigating a design-basis accident, it is not necessary to require the operability of the containment vacuum pumps for plant startup or require a shutdown for the sole reason of inoperable containment vacuum pumps.

Surry Technical Specification 3.15 prevents a unit startup and requires a unit shutdown if at least one containment vacuum pump and associated flow path are not available. However, it is reasonable to assume, based upon continued plant experience, that containment vacuum, once established, will remain adequate even if the Containment Vacuum System is not operational. If containment vacuum is not adequate, Technical Specification 3.8.B requires shutdown.

Proposed Change The proposed change deletes Technical Specification 3.15 and its associated basis from the Surry Technical Specifications. For clarification, the time requirements for the reactor to be brought to the hot shutdown condition and the cold shutdown condition are specified in Technical Specification 3.8.B. The UFSAR Section 6.3.2 is added to the list of references in 3.8.B. The proposed change does not involve any physical modifications and does not affect setpoints, operating parameters, or operating methods. Containment vacuum is still required by Technical Specification 3.8 to be maintained consistent with initial conditions assumed in the accident analyses. The containment will, therefore, respond as previously analyzed and peak pressure will not increase.

e 10 CFR 50.92 SIGNIFICANT HAZARDS CONSIDERATION EVALUATION The operation of Surry Power Station in accordance with the proposed amendment would not:

(1) Involve a significant increase in the probability or consequences of an accident previously evaluated. During design basis accident conditions, the Containment Vacuum System is isolated and is not used to depressurize the containment. As described in the safety evaluation in the UFSAR, the Containment Vacuum System will not be required to operate for several months after a LOCA to maintain containment subatmospheric to prevent uncontrolled releases. Deletion of the Containment Vacuum System technical specification has no effect on any failure mechanism which could lead to a Loss of Coolant Accident (LOCA).

Adequate initial containment vacuum, as assumed in the UFSAR, is assured by Technical Specification 3.8. Containment response will, therefore, be as previously analyzed and consequences will not increase; or (2) Create the possibility of a new or different kind of accident from any accident previously evaluated. The proposed change creates no new failure modes and no change in operation or surveillance is being made. Therefore, no new accident or malfunction scenarios are introduced by the change. As noted above, no accident consequences other than that presently evaluated in the UFSAR are introduced by this change, nor does this change affect any accident analysis assumption; or (3) Involve a significant reduction in a margin of safety. Since, as stated above, initial containment vacuum is assured by Technical Specification 3.8, peak containment pressure in a LOCA would be as previously analyzed, and the safety margin is not reduced.