ML20070S759

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Proposed Tech Specs Revising LCO 3.7.7 to Note That Provisions of TS Not Applicable While Performing Actions Associated W/Tornado Warning
ML20070S759
Person / Time
Site: Sequoyah  Tennessee Valley Authority icon.png
Issue date: 05/18/1994
From:
TENNESSEE VALLEY AUTHORITY
To:
Shared Package
ML20070S732 List:
References
TVA-SQN-TS-94, TVA-SQN-TS-94-0, NUDOCS 9405240187
Download: ML20070S759 (8)
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ENCLOSURE 1 PROPOSED TECilNICAL SPECIFICATION CilANGE SEQUOYAll NUCLEAR PLANT UNITS 1 AND 2 DOCKET NOS. 50-327 AND 50-328 (TVA-SQN-TS-94-05)

LIST OF AFFECTED PAGES UniL1 3/4 7-17 UniL2 3/4 7-17 8

9405240107 940519

PDR ADLCK-05000327
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PLANT SYSTEMS

}3/4.7.7 CONTROL ROOS EMERGENCY VENTILATION SYSTEM

,LlMITING CONDITION FOR OPERATION 3.7.7 Two independent control room emergency ventilation systems shall be R16 OPERABLE.

APPLICABILITY: ALL MODES ACTION:

MODES 1, 2, 3 and 4 With one control room emergency ventilation system inoperable, restore the inoperable system to OPERABLE status within 7 days or be in at least HOT STANDBY within the next 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 following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

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MODES 5 and 6

a. With one control room emergency ventilation system inoperable, restore the inoperable system to OPERABLE status within 7 days or s initiate and maintain operation of the control room emergency

) ventilation system in the recirculation mode.

b. With both control room emergency air ventilation systems inoperable, suspend all operations involving CORE ALTERATIONS or positive reactivity changes.
c. The provisions of Specification 3.0.3 are not applicable in MODE 6.

J. m ivere a me,r,ew , > o > u< mr muasa sa na 5 se a enar ,a scr,.n Auwa rv ~ a ^

e M. The provisions of Specification 3.0.4 are not applicable. T"d"" "A'*d" h168 SURVEILLANCE REQUIREMENTS 4

4.7.7 Each control room emergency ventilation system shall be demonstrated R16 OPERABLE:

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a. At least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> by verifying that the control room air temperature is less than or equal to 104 F.
b. At least once per 31 days on a STAGGERED TEST BASIS by initiating, from the control room, flow through the HEPA filters and charcoal adsorbers and verifying that the system operates for at least 15 minutes,
c. At least once per 18 months or (1) after any structural maintenance on the HEPA filter or charcoal adscrber housings, or (2) following painting, fire or chemical release in any ventilation zone communicating with the system by:

SEQUOYAH - UNIT 1 3/4 7-17 Amendment No. 12, 164 November 6, 1992

PLANT SYSTEMS

) 3/4.7.7 CONTROL ROOM EMERGENCY VENTILATION SYSTEM LIMITING CONDITION FOR OPERATION 3.7.7 Two independent control room emergency ventilation systems shall be OPERABLE.

APPLICABILITY: ALL MODES ACTION:

MODES 1, 2, 3 and 4:

With one control room emergency ventilation system inoperable, restore the inoperable system to OPERABLE status within 7 days or be in at least HOT STANDBY within the next 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 following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

Ncic ; r,a rt>osaa oF setwenrood 1 M ^!d M*T ^!h"*W ^* ^ W' of ^"'*S Anot ^ttD MODES 5 and 6: mA rown MrMe

a. With one control room emergency ventilation system inoperable, restore the inoperable system to OPERABLE status within 7 days or initiate and maintain operation of the control room emergency

} ventilation system in the recirculation mode. ~-

b. With both control room emergency air ventilation systems inoperable, suspend all operations involving CORE ALTERATIONS or positive reactivity changes,
c. The provisions of Specification 3.0.3 are not applicable in MODE 6.
d. ron usw,am er morneria s o 3 m rw Artuswc M nn s As a wU d AdhM AwWd Wstk A e% The provisions of Specification 3.0.4 are not applicable, raaoo waru,va l R154 SURVEILLANCE REQUIREMENTS 4.7.7 Each' control room emergency ventilation system shall be demonstrated -

OPERABLE:

a. /.t least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> by verifying that the control room air temperature is less than or equal to 104*F.
b. At least once per 31 days on a STAGGERED TEST BASIS by initiating, from the control room, flow through the HEPA filters and charcoal adsorbers and verifying that the system operates for at least 15 minutes.
c. At least once per 18 months or (1) after any structural maintenance on the HEPA filter or charcoal adsorber housings, or (2) following painting, fire or chemical release in any ventilation zone communicating with the system by:

SEQUOYAH - UNIT 2 3/4 7-17 Amendment No.154 November 6, 1992

s.

ENCLOSURE 2 PROPOSED TECIINICAL SPECIFICATION CllANGE SEQUOYAll NUCLEAR PLANT UNITS 1 AND 2 DOCKET NOS. 50-327 AND 50-328 (TVA-SQN-TS-94-05)

DESCRIPTION AND JUSTIFICATION FOR Ti!E PROVISIONS OF SPECIFICATION 3.0.3 NOT BEING APPLICALBE WIIILE PERFORMING ACTIONS ASSOCIATED WITil A TORNADO WARNING

o Destription of Changa TVA proposes to modify the Sequoyah Nuclear Plant (SQN) Units 1 and 2 technical specifications (TSs) to revise the action statement of TS Limiting Condition for Operation (LCO) 3.7.7. This revision will add a note to the action statement of the subject LCO to indicate that the provisions of TS LC0 3.0.3 are not applicable while performing actions associated with a tornado warning.

Reaann_for_ Change rhis change is necessary to prevent entry into TS LCO 3.0.3 every time a tornado warning is issued by the National Weather Service. the SQN abnormal operating instructions for a tornado warning require several tornado dampers in the control room emergency ventilation system (CREVS) to be closed. The tornadu e;vspers are in the pressurizing air supply flow path to CREVS. The pressurizing air supply is required to ensure a positive pressure in the control room during accident conditions.

Closure of the tornado dampers makes both trains of CREVS inoperable.

Therefore, entry into TS LCO 3.0.3, a possible dual-unit shutdown, and a subsequent follow-up licensee event report are required as a result of a tornado warning.

Justification for Change SQN's design basis for CREVS is to ensure the control room environment will support the activities required of Operations' personnel during accident conditions. When activated, CREVS provide- a mixed flow of outside and recirculated air through devices for temperature, humidity, and air cleanup control. In this mode, the control room is maintained greater than 1/8-inch water gauge positive pressure to outside atmosphere and slight positive pressure to adjacent areas. CREVS has sufficient redundancy to ensure a single failure will not prevent the accomplishment of these safety functions (reference the Updated Final Safety Analysis Report [UFSAR], Sections 6.4.1 and 9.4.1).

The flow path for pressurizing air to CREVS has the ability to be isolated during conditions when tornadoes are likely in the SQN site area. This provision ensures that the ef fect of a tornado will not damage critien1 equipment in the CREVS as well as other control building equipment. When these tornado dampers are closed, the fresh air portion of the normal control room ventilation system and CREVS is not available. This requires the systems to run in a' recirculation mode that does not provide control room pressurization. During normal operation conditions, this has no impact because temperature, humidity, and air '

cleanup control are still maintained in the recirculation mode. For accident conditions, the same control functions are maintained, but the pressurization feature is not available. This would increase the

's l potential for inleakage of contaminated air to the contro? room.

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However, the occurrence of an accident creating a contaminated air i condition concurrent with a tornado is not postulated for SQN (reference  ;

the UFSAR 6.4.1.2). This is based on the unlikely potential for both to l occur simultaneously and the facility design to withstand the effects of j a . tornado without creating a design basis accident Therefore, the only impact to isolating the tornado dampers is the loss of pressurizing air for the control room, which will not impact control 's room habitability. This function is only essential during accident conditions that are not postulated to occur when a tornado is near the site.

EnYlRORmental_lmpac1_EYaluation The proposed change request does not involve an unreviewed environmental question because operation of SQN Units 1 and 2 in accordance with this change would not:

1. Result in a significant increase in any adverse environmental impact ,

previously evaluated in the Final Environmental Statement (FES) as I modified by the staff's testimony to the Atomic Safety and Licensing Board, supplements to the FES, environmental impact appraisals, or decisions of the Atomic Safety and Licensing Board.

2. Result in a significant change in effluents or power levels.
3. Result in matters not previously reviewed in the licensing basis for SQN that may have a significant environmental impact.

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.I Enclosure 3 PROPOSED TECHNICAL SPECIFICATION CHANGE SEQUOYAH NUCLEAR PLANT UNITS 1 AND 2 DOCKET NOS. 50-327 AND 50-328 (TVA-SQN-TS-94-05)

DETERMINATION OF NO SIGNIFICANT HAZARDS CONSIDERATION i

Significant Hazards Evaluation TVA has evaluated the proposed technical specification (TS) change and has determined that it does not represent a significant hazards consideration based on criteria established in 10 CFR 50.92(c).

Operation of Sequoyah Nuclear Plant (SQN) in accordance with the proposed amendment will not:

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

The control room emergency ventilation system (CREVS) was designed to ensure control room habitability during accident conditions. The design basis of SQN does not include an accident creating a contaminated air condition concurrent with a tornado. The ability of the CREVS to perform its design function has not been affected by this change. The proposed change will not increase the possibility or consequences of an accident.

2. Create the possibility of a new or different kind of accident from any previously analyzed.

An accident involving a contaminated air condition and a tornado have been analyzed as part of the SQN design basis. Both accidents are assumed to occur independently. This change does not create a new or different accident not previously analyzed.

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

The design basis of the CREVS is not impacted by this TS change.

There is no change in any assumptions made in the Final Safety Analaysis Report. Therefore, there is no reduction in the margin of safety as a result of this change.

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