ML18153B213

Proposed Tech Specs,Modifying as-found Test Acceptance Criterion for Pressurizer Safety Valves

ML18153B213
Person / Time
Site:	Surry
Issue date:	01/24/1995
From:	VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:
Shared Package
ML18153B212	List: ML18153B211 ML18153B213
References
NUDOCS 9502010249
Download: ML18153B213 (5)

Text

e Attachment 2 Technical Specifications Changes Surry Power Station L TS 3.1-3 e. Reactor power shall not exceed 50% of rated power with only two pumps in operation unless the overtemperature AT trip setpoints have been changed in accordance with Section 2.3, after which power shall not exceed 60% with the inactive loop stop valves open and 65% with the inactive loop stop valves closed. f. When all three pumps have been idle for > 15 minutes, the first pump shall not be started unless: (1) a bubble exists in the pressurizer or (2) the secondary water temperature of each steam generator is less than 50°F above each of the RCS cold leg temperatures.

2. Steam Generator A minimum of two steam generators in non-isolated loop shall be operable when the average reactor coolant temperature is greater than 350°F. 3. Pressurizer Safety Valves

• a. Three valves shall be operable when the head is on the reactor vessel and the reactor coolant average temperature is greater: than 350°F, the reactor is critical, or the Reactor Coolant System is, not connected to the Residual Heat Removal System. b. Valve lift settings shall be maintained at 2485 psig +/- 1 percent* The as-found tolerance shall be +/-3% and the as-left tolerance shall be +/-1%. Amendment Nos.

e Attachment 3 Significant Hazards Consideration Determination Surry Power Station Basis for No Significant Hazards Determination A safety evaluation has been performed which justifies increasing the current Technical Specifications pressurizer safety valve lift setpoint acceptance criterion from +/-1 % as-found and +/-1 % as-left to +/-3% as-found and +/-1 % as-left. This change is being made to quantify inherent safety margin in the current as-found lift setpoint acceptance criterion and to provide greater operational flexibility in meeting periodic test requirements established by the safety analysis.

Surry Technical Specification 3.1.A.3.b indicates the currently applicable

+/-1 % found and as-left setpoint acceptance criterion for the pressurizer safety valves. Accident analyses and evaluations were performed to support a pressurizer safety valve setpoint acceptance criterion increase to +/-3% as-found.

In addition, an as-found pressurizer safety valve lift setpoint acceptance criterion as high as +/-3% is supported by the ANSI-OM-1 inservice performance testing standard.

The proposed setpoint acceptance criterion increase does not change the nominal setpoint of the pressurizer safety valves. Only the allowable tolerance about the existing setpoint is changed. The proposed Technical Specifications change does not involve a significant hazards consideration because operation of Surry Units 1 and 2 in accordance with this change would not: a. involve a significant increase in the probability or consequences of an accident previously evaluated.

Affected safety-related parameters were analyzed for a change to Surry Units 1 and 2 Technical Specification 3.1.A.3.b.

It was determined that the primary and secondary side overpressure safety limits would not be exceeded in the most limiting overpressure transient (Loss of Load, Locker Rotor, and Rod Withdrawal events) with the pressurizer safety valve lift setpoint acceptance criterion increased to +/-3%. The DNBR results of transients impacted by the setpoint acceptance criterion increase are not affected by the proposed change. The increased setpoint acceptance criterion will not result in an inadvertent opening of the pressurizer safety valves. Since the proposed change involves no alterations to the physical plant, the probability of occurrence of an accident or malfunction of equipment important to safety previously evaluated is not increased.

b. create the possibility of a new or different kind of accident from any accident previously identified.

The proposed change to Surry Units 1 and 2 Technical Specification 3.1.A.3.b does not involve any alterations to the physical plant which would introduce any new or unique operational modes or accident precursors.

Only the allowable tolerance about the existing setpoint will be changed. c. involve a significant reduction in a margin of safety. It was determined that the most limiting overpressure transients do not result in maximum pressures in excess of the primary and secondary side overpressure limits. The DNBR results of affected transients are not made more limiting by the proposed setpoint tolerance increase.

Therefore, the margin of safety is unchanged by the proposed increase in the safety valve setpoint acceptance criterion.

Therefore, pursuant to 1 O CFR 50.92 and based on the above considerations, it has been determined that this change does not involve a significant safety hazards consideration.