ML18153C436

Proposed Tech Specs Revising Pressure at Which Leak Rate Testing Performed & Defining Test Pressure for Emergency Escape Airlock

ML18153C436
Person / Time
Site:	Surry
Issue date:	11/14/1990
From:	VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:
Shared Package
ML18153C435	List: ML18153C434 ML18153C436
References
NUDOCS 9011200189
Download: ML18153C436 (7)

Text

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ATTACHMENT 1 SURRY POWER STATION PROPOSED TECHNICAL SPECIFICATION CHANGE 10 CFR 50 APPENDIX J TEST PRESSURES 9011200189 901114 '\

PDR ADOCK 05000280 I P PDC I

TS 3.8-3

1

• The shutdown margins are selected based on the type of activities that are being carried out. The 5 percent ~k/k shutdown margin during refueling precludes criticality under any circumstances, even though fuel and control rod assemblies are being moved.

The allowable value for the containment air partial pressure is presented in TS Figure 3.8-1 for service water temperatures from 25 to 92°F. The allowable value varies as shown in TS Figure 3.8-1 for a given containment average temperature. The RWST water shall have a maximum temperature of 45°F.

The horizontal limit lines in TS Figure 3.8-1 are based on LOCA peak calculated pressure criteria, and the sloped line is based on LOCA subatmospheric peak pressure criteria.

The curve shall be interpreted as follows:

The horizontal limit line designates the allowable air partial pressure value for the given average containment temperature. The horizontal limit line applies for service water temperatures from 25°F to the sloped line intersection value (maximum service water temperature).

From TS Figure 3.8-1, if the containment average temperature is 112°F and the service water temperature is less than or equal to 83°F, the allowable air partial pressure value shall be less than or equal to 9.65 psia. If the average containment temperature is 116°F and the service water temperature is less than or equal to 88°F, the allowable air partial pressure value shall be less than or equal to 9.35 psia. These horizontal limit lines are a result of the higher allowable initial containment average temperatures and the analysis of the pump suction break.

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• TS 4.4-2

b. The leakage rate test will be performed at a pressure of at least 45.0 psig.

c. The measured leakage rate Lam shall not exceed 75% of the design basis accident leakage rate (La) 0.1 weight percent per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> at Pressure Pa.

2. Type B and C tests will be performed at a pressure of at least 45.0 psig in accordance with the provisions of Appendix J, Section 111.B.

and C. 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 personnel airlock, the seals will be tested to at least 45 psig to verify that they are properly sealed. The emergency escape airlock seals will be tested at 1O psig within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> of use.

C. Acceptance Criteria Type A, B, and C tests will be considered to be satisfactory if the acceptance criteria delineated in Appendix J, Sections III.A.5(b) 111.B.3.,

and 111.C.3 are met.

D. Retest Schedule The retest schedules for Type A, B, and C tests will be in accordance with Section 111.D of Appendix J.

E. Inspection and Reporting of Tests Inspection and reporting of tests will be in accordance with Section V of Appendix J.

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

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• TS 4.4-3 The containment is designed for a maximum pressure of 45 psig. The containment 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 will not rise above 45 psig for any postulated loss-of-coolant accident.

The initial test pressure for the Type A test is 47.0 psig to allow for containment expansion and equalization. A review was performed to determine the effects of pressurizing containment above its design pressure of 45.0 psig which is also (Pa), This review was based on the original containment test at 52 psig. During that test, the calculated stresses were found to be well within the allowable yield strength of the structural reinforcing bars, therefore performance of the Type A test at 47 psig will have no detrimental effect on the containment structure.

All loss-of-coolant accident evaluations have been based on an integrated containment leakage rate not to exceed 0.1 % 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 provides assurance that the overall airlock leakage will not become excessive due to seal damage during the intervals between airlock leakage tests. Because the test pressure is applied under the the

• emergency escape airlock door seals (between the seating surfaces) only 1O psig is used. The 1O psig test is deemed by the manufacturer to be a comparable test.

References FSAR Section 5.4 Design Evaluation of Containment Tests and Inspections 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 "Primary Reactor Containment Leakage Testing for Water Cooled Power Reactors"

ATTACHMENT 2 SURRY POWER STATION SIGNIFICANT HAZARDS CONSIDERATION DETERMINATION

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DISCUSSION The proposed Technical Specification change to Section 4.4.B will require Type A, B, and C testing be performed at 45 psig (containment design pressure) rather than 39.2 psig (previous calculated peak pressure). This change is necessary to ensure that the containment is tested at a pressure equal to or greater than calculated peak accident pressure. The latest reanalysis, performed to support the reevaluation of the service water inventory calculations (canal inventory), indicates that accident pressure will peak at 44.98 psig. This is the worst case, assuming normal safeguards and minimum containment spray. The actual Type A, B, and C testing will be performed at greater than 45 psig (i.e., 47 psig). An evaluation was performed to determine the effects of pressurizing the containment above the design pressure. The evaluation was based on the original containment pressure test at 52 psig. During the test, the calculated stresses were found to be well within the allowable yield strengths of the structural reinforcing bars. Therefore, performance of Type A testing at 47 psig will have no detrimental effect on the containment structure.

This proposed Technical Specification change will also specify the pressure at which the emergency escape airlock door seals are tested 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> after use, in accordance with 1o CFR 50, Appendix J,Section III.D.2(b)(iii). Appendix J permits alternate testing methods when it is impractical to test at design pressure, but requires modification of the Technical Specifications for consistency. Currently, the Technical Specification (4.4.B.2) requires Type B tests be performed at design accident pressure. The required 6 month surveillance is performed by pressurizing the escape hatch between the doors at design pressure. However, the test that is required 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> after each use tests only the seals. The manufacturer has recommended a 1O psi differential pressure test applied under the seal (between the seating surfaces) as a comparable alternative.

For the above changes, the basis is being updated to reflect the new test pressures.

In addition to the above changes, a typographical error is also being corrected. In the basis of Section 3.8, the operational range of service water temperature is being corrected to be consistent with Figure 3.8-1. The 92°F, on Figure 3.8-1, is consistent with the maximum service water temperature used in the safety analysis.

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SIGNIFICANT HAZARDS CONSIDERATION Virginia Electric and Power Company has reviewed the proposed changes against the criteria of 10 CFR 50.92 and has concluded that the changes as proposed do not pose a significant hazards consideration. Specifically, operation of the Surry Power Station in accordance with the proposed changes will not:

1. Involve a significant increase in the probability of occurrence or consequences of any accident previously evaluated. The reanalysis of containment response was performed as part of an evaluation to resolve a concern identified with the canal inventory. The reanalysis results remain within the design basis envelope. In addition, plant design and operations have not been altered. Therefore, the probability of occurrence or consequences of any accident have not increased.

2. Create the possibility of a new or different type of accident from any accident previously evaluated. Plant design and operations have not been changed. The changes in accident analysis input do not affect system design or operation. Therefore no new or different kind of accident is created.

3. Involve a significant reduction in a margin of safety. No physical plant modifications, or changes in plant operations are being made. Although an accident analysis assumption is being changed the results of the analysis remain with the design envelope (45 psig containment design pressure) and the safety margin is unchanged.