ML20091D299

Proposed Tech Specs,Revising Surveillance Requirement 4.6.1.3.a to Delete 15-minute Time Period When Performing Pressure Decay Test for Containment Air Lock Door Seals

ML20091D299
Person / Time
Site:	Sequoyah
Issue date:	05/25/1984
From:	TENNESSEE VALLEY AUTHORITY
To:
Shared Package
ML20091D297	List: ML20091D293 ML20091D299
References
NUDOCS 8405310126
Download: ML20091D299 (6)

Text

l CO.NTAINMENT SYSTEMS SURVEILLANCE RE0uIREMENTS 4.6.1.3 Each containment air lack shall be demonstrated OPERABLE:

a. After each opening, except when the air lock is being used for multiple entries, then at least once per 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, by verifying seal leakage less than or equal to.0.01 L when a the volume between the door seals is pressuri:ed to greater than or equal to 6 psig,

b. By conducting an overall air lock leakage test at not less than P3 (12 psig) and by -

within its limit:jerifying the overall air lock leakage rate is

1. At least once per six months, and

2. Prior to establishing CONTAINMENT INTEGRITY if opened when CONTAINMENT INTEGRIT',' was not required when maintenance has been performed on the air lock that could affect the air lock sealing capability.*

c. At least once per 6 months by verifying that only one door in each air lock can be opened at a time.

The provisions of Specification 4.0.2 are not applicable.

• Exemption to Appendix "J" of 10 CFR 50.

SEQUOYAH - UNIT 2 3/4 6-8 8405310126 840525 PDR ADOCK 05000327 P PDR

CONTAINMENT SYSTEMS SURVEILLANCE REQUIREMENTS 4.6.1.3 Each containment air lock shall be demonstrated OPERABLE:

a. After each opening, except when the air lock is being used for multiple entries, then at least once per 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, by verifying seal leakage less than or equal to 0.01 L, when the volume between the I door seals is pressurized to greater than or equal to 6 psig.

b. By conducting an overall air lock leakage test at not less than P a

(12 psig) and by verifying the overall air lock leakage rate is within its limit:#

1. At least once per six months, and

2. Prior to establishing CONTAINMENT INTEGRITY if opened when CONTAINMENT INTEGRITY was not required when maintenance has .

been performed on the air lock that could affect the air lock '

sealing capability.*  ;

c. At least once per 6 months by ' verifying that only one door in each air lock can be opened at a time.

The provisions of Specification 4.0.2 are not applicable.

• Exemption to Appendix "J" of 10 CFR 50.

SEQUOYAH - UNIT 1 3/4 6-8 a

a a

ENCLOSURE 2 JUSTIFICATION FOR PROPOSED TECHNICAL SPECIFICATIONS

JUSTIFICATION FOR PROPOSED TECIINICAL SPECIFICATION CILtNGES Reason for Change This surveillance requirement is presently being satisfied by a pressure decay test over a 15 minute period, as required by SR 4.6.1.3.a. This change would allow an airflow rotometer or mass flowmeter test and is required in order to: (1) upgrade l the accuracy of the testing, (2) meet ALARA considerations, (3) reduce unnecessary manpower expenditures, and (4) remove nonconservatisms from the test method.

Justification for Change This change is justified based on the following:

1. Due to the small volume in the door seal, an acceptable leakrate is achieved in the pressure decay test if the pressure decays from 6.4 psig to O psig in five or j more seconds (contrary to the 15-minute requirement). Leakrate accuracy is increased by performing an airflow rotometer test which removes uncertainties and nonconservatisms associated with system volume (tubing and gauge connections, seal compressibility), temperature changes, and reduced leakrate due to decaying pressure. The effect of system volume and reduced leakrate due to decaying pressure is illustrated in the attached table.

2. Presently, individuals may be contained inside primary containment for up to 15 minutes during conduct of the test. A rotometer test or mass flowtest may be conducted in approximately one minute and significantly reduce radiation exposure and manpower expenditures of both the tester and individuals contained inside containment. This test is performed on eight door seals every Monday, Wednesday, and Friday.

3 The attached table provides a comparison of test data from airflow-rotometer tests and pressure-decay tests. The data indicates that the rotometer test is the most conservative.

Attached is the significant hazards consideration determination which states that no significant hazards considerations are involved.

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COMPARISON OF TEST DATA FOR PRESSURE DECAY AND ROT 0 METER LEAKRATE TESTS ON SEQUOYAH UNIT 2 AIRLOCKS Leakrate SCFH Airflow ~

Pressure-Decay Corrected Pressure- Rotometbr Test Decay Test # Test Item Tested Lower airlock inner 0.0008 0.0254 door seal 0.0005 Lower airlock outer 0.1752 door seal 0.0092 0.0151 Upper airlock inner 0.0018 0.0029 0.0305 door seal Upper airlock outer 0.0305 0.0013 0.0021 door seal CCorrected for volume of connecting tubing and 6auge.

e

SIGNIFICANT HAZARDS CONSIDERATIONS

1. Is the probability of an occurrence or the consequences of an accident or malfunction of equipment important to safety previously evaluated in the safety analysis report increase? No.

The leakrate of the airlock door seals will be verified to be less than, or equal to, 0.01La (2.37 SCFH) using an acceptable test method in accordance with existing procedures (SI-159.2) at the required frequency.

2. Is the possibility for an accident or malfunction of a different type than evaluated previously in the safety analysis report created? No A different type of accident or malfunction is not created since the leakrate of the airlock door seal is verified to be less than cr equal to 0.01La.

3 Is the margin of safety as defined in the basis of any technical specification reduced? No The margin of safety is not reduced since the leakrate limit is 4

satisfied at the same frequency.

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