ML18152A899

Proposed Tech Specs,Allowing Entry Into Containment Personnel Airlock During Power Operations to Make Repairs on Inner Door of Personnel Airlock

ML18152A899
Person / Time
Site:	Surry
Issue date:	04/26/1988
From:	VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:
Shared Package
ML18152A898	List: ML18152A897 ML18152A899
References
NUDOCS 8805020206
Download: ML18152A899 (10)

Text

e ATTACHMENT I Proposed Technical Specification Change Surry Power Station Units I and 2

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TS 1. 0-5 for operational activities provided that they are under administrative control and are capable of being closed immediately if required.

2. Blind flanges are installed where required.

3. The equipment access hatch is properly closed and sealed.

4. At least one door in the personnel airlock is properly closed and sealed.

5. All automatic containment isolation valves are operable or are deactivated and secured in their closed position under administrative control.

6. The uncontrolled containment leakage satisfied Specification 4.4.

I. Reportable Event A Reportable Event shall be any of those conditions specified in Section 50.73 to 10 CFR Part 50.

e TS 3.8-1 3 .'8 CONTAINMENT Appl icabil itv Applies to the integrity and operating pressure of the reactor containment.

Objective To define the limiting operating status of the reactor containment for unit operation.

Specification A. Containment Integrity and Operating Pressure

1. The containment integrity, as defined in TS Section 1. 0, sha 11 not be violated unless the reactor is in the cold shutdown condition.*

2. The reactor containment shall not be purged whenever the Reactor Coolant System temperature is above 200°F.

3. The inside and outside isolation valves in the steam jet air ejector suction line shall be locked, sealed or otherwise secured closed whenever the Reactor Coolant System temperature is above 200°F.

4. The Reactor Cool ant System temperature and pressure must not exceed 350°F and 450 psig, respectively, unless the air partial pressure in the containment is at a value equal to, or below, that specified in TS Figure 3.8-1.

5. The containment integrity shall not be violated when the reactor vessel head is unbolted unless a shutdown margin greater than 5 percent ~k/k is maintained.

• In the event of failure of the personnel airlock inner door seal to meet the leakage test acceptance criteria, the outer personnel airlock door may be opened briefly to allow access for the repair and retest of the inner door.

TS 4.4-3 The leak tightness testing of all liner welds was performed during con-struction by welding a structural steel test channel over each weld seam and performing soap bubble and halogen leak tests.

The containment is designed for a maximum pressure of 45 psig. The con-tainment is maintained at a subatmospheric air partial pressure which varies between 9 psia and 11 psia depending upon the cooldown capability of the Engineered Safeguards and is not expected to rise above 39.2 psig for any postulated loss-of-coolant accident.

All loss-of-coolant accident evaluations have been based on an integrated containment leakage rate not to exceed O.1% of containment volume per 24 hr.

The above specification satisfies the conditions of 10 CFR 50.54(0) which stated that primary reactor containments shall meet the containment leakage test requirements set forth in Appendix J.

The limitations on closure and leak rate for the containment airlocks are required to meet the restrictions on containment integrity and containment leak rate. Surveillance testing of the airlock seals pro vi des assurance that the over a11 airlock leakage will not become excessive due to seal damage during the intervals between airlock leakage tests.

References FSAR Section 5.4 Design Evaluation of Containment Tests and Inspec-tions of Containment FSAR Section 7.5.1 Design Bases of Engineered Safeguards Instrumentation FSAR Section 14.5 Loss of Coolant Accident 10 CFR 50 Appendix J "Reactor Containment Leakage Testing for Water Cooled Power Reactors"

e ATIACHMENT 2 Description of Change No Significant Hazards Determinations

Description of Change and Safety Evaluation Personnel Airlock Leakage Repair Description of Change The Surry Power Station Units 1 and 2 Technical Specification Definition 1.H.4 "Containment Integrity" requires that at least one door in the personnel airlock be properly closed and sealed. Technical Specification 3.8.A.1 requires that containment integrity as defined in 1.H.4 be preserved unless the reactor is in the cold shutdown condition. In addition, the Technical Specification 4.4.B.2 requires that, within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> after use of the per-sonnel airlock, the seals be tested at least at the peak calculated accident pressure to verify that they are properly sealed.

During power operation, there is an occasional need to enter the containment while it is in a subatmospheric condition. Containment entry may be required to identify leakage sources, perform immediate repairs or other operational activities to support continued operation. As required by T.S.4.4.B.2, the personnel airlock inner and outer door seals are tested within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> following closure.

Access to the containment while in a subatmospheric condition is performed by equalizing and opening the airlock outer door and then closing and sealing the outer door. The pressure in the airlock is then equalized with the contain-ment and the inner door is opened for the final access. This method ensures that at least one door on the personnel airlock is properly closed and sealed whenever the containment is in a subatmospheric condition. Interlocks provide additional assurance that the doors cannot be opened simultaneously while in a subatmospheric condition.

Fo 11 owing the final use of the airlock, the seals on the inner and outer personnel airlock doors are tested at equal to or greater than the peak calculated accident pressure. If the seal on the outer door fails to pass the acceptance criteria of the test, the . inner door is verified to be properly closed and sealed and the outer door seal is repaired and retested. If the

e e inner door seal fails, the outer door is verified to be properly closed and sea 1ed. However, the on 1y accept ab 1e method for repair and retest of the inner seal is by reopening the outer door to allow access to the inner door seal. During this brief period, the containment integrity requirements as defined in T. S.Section I. H. 4 cannot be met s i nee the inner door wil 1 be closed but may not be properly sealed.

Access to the containment through the equipment hatch escape lock is not an acceptable alternative for this repair and retest since it is only designed for emergency egress from the containment.

The proposed Technical Specifications change will provide for the access to the inner door for repair and retest of the inner door. Upon entry into the personnel airlock, the outer door.will be properly closed and sealed prior to initiating repair of the inner door.

The Technical Specification Definition of Containment Integrity (T.S. l.H.5) requires that automatic containment isolation valves be operable or be locked closed under administrative control. Many of the automatic containment isolation valves are air operated or directly actuated solenoid operated valves and therefore cannot be locked in the same manner as motor operated.

valves. The proposed amendment clarifies the requirement for inoperable automatic containment isolation valves by requiring that they be deactivated (power removed) and secured in their closed position under administrative control.

e SAFETY EVALUATION 50.92 No Significant Hazards Determination A. Personnel Airlock Inner Door The proposed change to the Surry Units 1 and 2 Technical Specifications clarifies the requirements for containment integrity to permit repair and retest of the personnel airlock inner door seal by addressing the need to open the outer door of the personnel airlock. This proposed change has been reviewed to determine if a significant safety hazard exists as defined in 10CFR50.92. The period of time of concern is when leakage exists through the inner door seals and the short time (several minutes) that the outer door is opened for access.

Spec i fi ca 11 y, the operation of Surry Power Station with the proposed amendment will not:

1. Involve a significant increase in the probability or consequences of an accident previously evaluated.

The probability of occurrence of a design basis ace i dent has not been increased during this condition. However, there may be an effect on the consequences of an accident if there is a. pressuriza-tion (Design Base Accident) of the containment during the time the outer door is opened and leakage through the inner door seal exists.

A quantitative analysis of this effect has not been performed. The potential increase in the consequences of an event is considered to be insignificant for the following reasons:

a. Entry through the personnel airlock during subatmospheric conditions is acceptable based on the current limiti_ng condi-tions for operation provided that at least one airlock door is closed and properly sealed. As such, the required containment integrity condition necessary for limiting the consequences of an accident can be satisfied by a single door.

b.

e The amount of leakage through the inner door seal may not meet the acceptance criteria of the surveillance test. If the seal cannot be repaired and retested at this time, the outer door would be closed and sealed. If the inner door seal leakage is excessive, the pressure equalization necessary to open the outer door could not be accomplished and repairs could not be made until the unit is in a co 1d shutdown condition with the containment pressure returned to atmospheric.

c. In the event of a containment pressurization due to a design basis accident during the entry through the outer door, the increased pressure in the containment would more fully seat the inner door and would tend to reduce the seal leakage.

d. The probability of a design basis accident occurring during the brief period of time that the outer door is opened for access to repair the inner door sea1 is considered to be ins i gn ifi cant.

Although the consequences of the accident may increase slightly, the probability of the event is sufficiently small so that the overall increase in consequences is considered insignificant.

2. Create the possibility of a new or different kind of accident from any evaluated previously in the safety analysis report. As previously discussed, a quantitative analysis of releases has not been made. However, the potential for an accident concurrent with repair activities and hence the potential consequences are considered to be insignificant.

3. Involve a significant reduction in the margin of safety.

Specifically, the redundancy in the design of the personnel airlock door and the capability to 1imi t the leakage through the airlock door may be reduced during this brief evolution. However, the reduction of margin is considered insignificant based on the small

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• probability of concurrently opening the outer door and having a design basis event. In addition, the effort expended to repair the inner door seal and ensure the operability of both personnel airlock seals improves the capability of the airlock to withstand a containment pressurizatioh and restore the redundancy in the design of the personnel airlock. Repair of the airlock door seals is considered prudent and is normally performed even though the Technical Specification (1.H.4) requires only one door seal to be operable.

B. Inoperable Automatic Containment Isolation Valves The proposed change to the T.S. l.H.5 Definition clarifies the action for an inoperable automatic containment isolation valve. This proposed change has been reviewed to determine if a significant safety hazard as defined in 10 CFR 50.92 is created. Specifically, the operation of Surry Power Station with the proposed amendment will not:

1. Involve a significant increase in the probability or consequences of an accident previously evaluated. This amendment does not alter the requirement to ensure that inoperable containment isolation valves are closed (post accident required position). It clarifies the actions necessary to ensure that valves with air operated (solenoid valves) actuators or direct acting solenoid valves are properly secured. Specific actions for deactivating and securing inoperable valves are provided in the Surry Administrative Procedure (SUADM-0-26).

2. Create the possibility of a new or different kind of accident from any evaluated previously in the safety analysis report. The requirement to close inoperable contaioment isolation valves is preserved but clarified for particular types of valves.

3. Involve a significant reduction in the margin of safety. The margin of safety will not be affected since the inoperable valves will be closed.