ML20098D725

Proposed TS 3/4.6.5.3 Re Ice Condenser Doors

ML20098D725
Person / Time
Site:	Sequoyah
Issue date:	05/26/1992
From:	TENNESSEE VALLEY AUTHORITY
To:
Shared Package
ML20098D719	List: ML20098D717 ML20098D725
References
CON-TVA-SQN-TS-92-04, CON-TVA-SQN-TS-92-4 NUDOCS 9205290305
Download: ML20098D725 (13)

Text

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ENCLOSURE 1 PROPOSED TECHNICAL SPECIFICATION (TS) CHANGE SEQUOYAI! NUCLEAR PLANT UNITS 1 AND 2 DOCKET NOS. 50-327 AND 50-328 l

(IVA-SQN-TS-92-04 ) l l

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l LIST OF AFFECTED PAGES '

UniL1 l 3/4 6-29 l

B3/4 6-5 UniL2 3/4 6-30 33/4 6-5 l

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l t-l 9205290305 920526 PDR ADOCK 05000327 P PDR

CONTAINMENT SYSTEMS ICE CONDENSER DOORS

i. MITING CONDITION FOR OPERATION 3.6.5.3 The ice condenser inlet doces, intarmediate deck doors, and top deck doors rnall be closed and OPER'M c.

f AfPLICABILITY: MODES 1, 2, 3 ac.s 4.

C ACTION:

4 stat k L Fet ReAsous Ov% T sgs Rmow %

W1 r more ice condenser doors oper. .therwise inope ablk POWER i

Ob OPERATION may continue for up to 14 oays provice the ce ced seo erature is '

moltitored at least once per 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> and the maximum ice bed temperature is maintained less than or equal to 27 F; otherwise, restore the doors to their l

cicsed positions or OPERABLE status (es applicable) within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> 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 />.

SUR/EILLANCE REQUIREMENTS 4.6.5.3.1 Inlet Doors - Ice condenser inlet doors shall be:

a. Continuously monitered and determined closed by the inlet door position monitoring system, and

b. R135 Demonstrated OPERABLE at least oncs per 18 months by:

1. Verifying that the torque required to initially open each door is less than or equal to 675 inch pounds.

2. V i -

. het g. wing uQuh4cpe-4 not impaired by ice, f rosty debris, Oz. OBsTR utTlop.

3. Varifying that the torque required to open each door is less R135!

than 195 inch pounds when the door is 40 degrees open. This torque is defined as the " door opening torque" and is equal to the nominal door torque ,alus a frictional torque component.

R135 I

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, SEQUOYAH - UNIT 1 3/4 6-29 Amendment No. 25 131 l March 2, 1990

CONTAINMENT SYSTEMS

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BASES event that observed sublimation rates are equal to or lower than design predic-tions after th ce years of operation, the minimum ice baskets weight may be adjusted downward. In addition, the number of ice baskets required to be I weighed each 9 months may be reduced after 3 years of operation if such a  !

reduction is supported by observed sublimation data.

3/4.6.5.2 ICE BE0 TEMPERATURE MONITORING SYSTEM )

l,i Tne OPERABILITY of the ice bed temperature monitoring system ensures tnat the capability is available for monitoring the ice temperature. In the event the monitoring system is inoperable, the ACTION requirements provide assurance I that the ice bed heat removal capacity will be retained within the specified time limits.

3/4.6.5.3 ICE CONDENSER D0 ORS The OPERABILITY of the ice condenser doors ensures that these doors will open because of the differential pressure between upper anc lower containment resulting from the blowdown of reactor coolant during a LOCA and that the blow- g down will be diverted through the ice condenser bays for heat removal and thus

% containment pressure control. The requirement that the doors be maintained

-~I closed during normal operation ensures that excessive sublimation of the ice g cur because of warm air intrusion from the lower containment.

~1NSERT k>

4.6. 4 INLET 000R POSITION MONITORING SYSTEM The OPERABILITY of the inlet door position monitoring system ensures that the capability is available for monitoring the individual inlet door position.

1- the event the monitoring system is inoperable, the ACTION requirements provide assurance that the ice bed heat removal capacity will be retained within the specified time limits.

l 3/4.6.5.5 DIVIDER BARRIER PERSONNEL ACCESS DOORS AND EQUIPMENT HATCHES The requirements for the divider barrier personnel access doors and equioment hatches being closed and OPERABLE ensure that a minimum byo u s steam flow will occur from the lower to the upper containment compartments during a LOCA. This condition ensures a diversion of the steam through the ice condenser j -bays that is consistent with the LOCA analyses.

l 3/4.6.5.6 CONTAINMENT AIR RETURN FANS The OPERABILITY of the centainment air return fans ensures that following i

a LOCA 1) the containment atmosphere is circulated for cooling by the spray system and 2) the accumulation of hydrogen in localized portions of the contain-ment structure is minimized.

SEQUOYAH - UNIT 1 B 3/4 6-5 Revised 08/18/87

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CONTAINMENT SYSTEMS ICE CONDENSER D0 ORS

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QMITINGCONDITIONFOROPERATION 3.6.5.3 The ice cc,ndenser inlet doors, intermediate deck doors, and top deck doors shall be closed and OPERABLE.

APPLICABILITY: MODES 1, 2, 3 and 4.

ACTION- O '~~ ~ y 3hT A t Fee RcAsoras Crmt9 7H AN AtTioN a..,

b. itti% more ice condenser doors open or other e_ erableY P C OPERATION may continue for up to 14 days provided the ice be emp rature is monitored at least once per 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> and the maximum ice bed temperature is maintained less than or equal to 27'F; otherwise, restore the doors to their closed positions or OPERABLE status (as applicable) within 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> 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 SHUTOOWN within the follos;:ng 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

SURVEILLANCE REQUIREMENTS 4.6.5.3.1 Inlet Doors - Ice condenser inlet doors shall be: l

a. Cor,tinuously monitored and determined closed by the inlet door position monitoring system, and

b. Demonstrated OPERABLE at least once per 18 months by: Rll8

1. Verifying that the torque required to initially open each door is less than or equal to 675 inch pounds.

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2. V fyTiigeTEa~t oFibrfng of'Tactr116oTh not impaired by ice, f rost,pf debris. Og. Oi,5 r-R.nctioso.

An s

3. Verifying that the torque required to open each door is less than Rllq 195 inch pounds when the door is 40 degrees open. This torque is defined as the " door opening torque" and is equal to the nominal door torque plus a frictional torque component. R11F l

SEQUOYAH - UNIT 2 3/4 6-30 Amendment No. 13 118 March 2, 1990

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CONTAINMENT SYSTEMS BASE.c event that observed sublimation rates are equal to or lower than design predictions after three years of operation, the minimum ice baskets weight may be adjusted downward. In addition, the number of ice baskets required to be weighed each 9 months may be reduced af ter 3 years of operation if such a reduction is supported by observed sublimation data.

3/4.6.5.2 ICE BED TEMPERATURE MONITORING SYSTEM The OPERABILITY of the ice bed temperature monitoring system ensures that the capability is available for monitoring the ice temperature. In the event the monitoring system is inoperable, the ACTION requirements prnvide assurance that the ice bed heat removal capacity will be retained within the specified time limits.

l 3/4.6.5.3 ICE CONDENSER DOORS The OPERABILITY of the ice condenser doors ensures that these doors will open because of the differential pressure between upper and lower containment resulting from the blowdown of reactor coolant during a LOCA and that the blow-down will be diverted through the ice condenser bays for heat removal and thus Bf containment pressure control. The requirement that the doors be maintained hyggg closed during normal operation ensures that excessive sublimation of the ice will not occur becatse of warm air intrusion from the lower containment.

L stRT b

..4 INLET DOOR POSITION MONITORING SYSTEM The OPERABILITY of the inlet door position monitoring system ensures that the capability is available for monitoring the individual inlet door position.

In the event the monitoring system is inoperable, the ACTION requirements-provide assurance that the ice bed heat removal capacity will be retained within the specified time limits.

3/4.6.5.5 DIVIDER BARRIER PE~ ONNEL ACCESS DOORS AND EQUIPMENT HATCHES The requirements for the divider barrier personnel access doors and equipment hatches being closed and OPERABLE ensure that a minimum bypass steam flow will occur from the lower to the upper containment compartments during a LOCA. This condition ensures a diversion of the steam through the ice condenser bays that is consistent with the Jz 'A analyses.

3/4.6.5.6 CONTAINMENT AIR RETURN FANS The OPERABILITY of the containment air return fans ensures that followirg a LOCA 1) the containment atmosphere is circulated for cooling by the spray system and ?) the accumulation of hydrogen in localized portions of the contain-ment structure is minimized.

SEQUOYAH - UNIT-2 B 3/4 6-5 Revised 08/18/87 CC' u-

INSERT A

n. With one or more ice condenser inlet doors inoperable due to being physically restrained from opening, restore all inlet doors to OPERABLE status within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> 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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INSERT B If an ice condenser inlet door is physically restrained from opening, the system function is degraded, and immedf3te action must be taken to restore the opening capability of the inlet door. Being physically restrained from opening is defined cs those conditions in which an inlet door is physically blocked from opening by !nstallation of a blocking device or by an obstruction from temporary or permanently installed equipment or is otherwise inhibited from opening such as may result from ice, frost, debris, or increased inlet door orening torque beyond the values specified in Surveillance D.equirement 4.6.5.3.1.

ENCLOSURE 2 PROPOSED TECHNICAL SPECIFICATION (TS) CHANGE SEQUOYAH NUCLEAR PLANT UNITS 1 AND 2 DOCKET NOS. 50-327 AND 50-328 (TVA-SQN-TS-9 2-04 )

DESCRIPTION AND JUSTIFICATION FOR REVISIONS OF ACTIONS FOR ICE CONDENSER DOORS 9

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. l Nessrlp_ tion _oLChange TVA proposes to modify the Sequoyah Nuclear Plant (SQN) Units 1 and 2 technical specifications (TSs) to revise TS 3/4.6.5.3, " Ice Condenser Doors " and its associated bases. This change resises Limited Condition for Operation (LCO) 3.6.5.3 to label the existing action ao "b" with the addition of an exclusion for conditions covered by Action "a" and adds an Action "a" that will read "a. With one or more ice condenser inlet doors inoperable due to being physically restrained from opening, restore all inlet doors to OPERABLE status within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> or be in at least 110T 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 S110TDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />."

Surveillance Requirement 4.6.5.3.1.b.2 has been revised to require verification that the opening of each inlet door is not impaired by ico, l frost, debris, or other obstruction.

Additionally. the associated TS Bases 3/4.6.5.3, is proposed to be changed to include a statement on the irportance of the ice condenser inlet doors not being physically restrained from opening and provides a definition of the term " physically restrained f rom ortning." The proposed woruing of the bases change reads:

"If an ict denser inlet door is physically restrained from opening, the system tunction is degraded, and immediate action must be taken to restore the opening capability of the inlet door. Being physically restrained from opening is defined as those conditions in which an inlet door.is physically blocked from oposing by installation of a blocking device or by an obstruction from temporary or permanently installed equipment or is otherwise inhibited from opening such as may result from ice, frost, debris, or increased inlet door opening torque."

Re 'on 'or_ Change The t : rent action statement for TS .3.6.5.3, " Ice Condenser Doors," is noncon evative in that it does not provide an appropriate action that addreer Se potential condition of-the inlet doors being physically restrained rom opering and, therefore, not capable of_ automatically opening, which is the primary safety-related function of the inlet doors. .The existing surveillance verifies that the inlet doors are not impaired by ice, frost, or debris, but does not appropriately verify that the inlet doors are not impaired by an obstruction. While the existing action stateuent does address inoperable ice condenser doors, it l inappropriately would allow continued power operation with one or more of I

the inlet doors (up to all of the doors) blocked closed for more than 14 aays. The proposed changes to the action statements are based on Westinghouse Electric Corporation, Methodically Engineered Restructured and Improved Technical Specifications Program, Phase III (draft NUREG-1431) and Revision 4A of Standard Technical Specifications (draft-NUREG-0452, dated ALgust 14, 1987) as issued to Texas Utilities Electric Company for Comanche Peak Unit-1.

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4 JnELtificatlan_for_. Change The ice ondenser is a passive device containing borated ice that is utilize? <n the event'of a loss-of-coolant accident (LOCA) or hieh-et rgy-line break (HELB) to absorb thermal energy. This ensures 9tsam is condensed, and the pressure energy is reduced to ensure cea- traen t integrity in the'early stages of an accident. The system works in conjunction with the containment sprey cystem to ensure containment integrity. In addition, it is also used as an iodine removal erstem via the chemical and physical properties of the ice to reduce the f,' produ:t iodine concentration in the post-LOCA and/or HELB ret environment. The ice condenrer is dis.ded into bcys with

,'ing a pair of doors in the lower compartment tha. are open on differential pressure to allow for initial steam flow gr condenser. The ice inventory is maintained in

.12- : - c+ . oteter baskets that are 48 feet high. The total ice inventory is - smately 2.25 million pounds based on the end-of-cycle random w The top deck, f r.termediate deck, containment shell, crer.e va- e vad walls form the boundaries of the upper ice condenser plenum the.t al' for mass and energy trxasport to the upper compartment for f or :bsr w .>11ng by the containment spray system.

?>c ice condenser _ inlet doors form the br :rier to air flow through the falet ports of the ice sendenser for normal plant operation. They also provide the continuatio.. of thermal insulation around the 1caer section of the crane wall to minimize. heat input that would promote. sublimation and mass transfer of ice in the ice condenser compartment. In-the event of a LOCA ann /or HELB causing a pressure increase in the lower compartment, the doors open, venting air and ste u in a relatively even manner into all sections of the ice condenser.

The doc: t anels a m ! > *:_ded with tension spring mechanisms that produce a smalf c.osing torque on the door pane.3 as they open. The magnitude of the cic3.ng torque is equivalent to providing approximately one pound per square foot pressic.s drop through the inlet ports with the door open to a pcsition equivalent to the full port flow area. The zero load position of the spring meenanisms is such that with zero differential presture across the door panels, the gasket holds the door slightly open. This setting provides assurance that all doors will be opened slightly upon removal of cold air head, therefore elima tting significar t inlet c maldistribution for very small incidents. For larger incidents, the doors open-fully, and flow distribution is controlled by the flow area and pressure drops of inlet ports. The doors are provided with shock absorber assemblies to dissipate the door kinetic energies enerated f deting large break incidents.

The SQN Final Safety Analysis Report (TSAR) states that the Jorce required to open the docts of the ice condenser shall be sufficiently low L such that the energs irom any leakage of steam through the divider p barrier can be readi;y ssorbed by the containment rpeny system without exceeding containment design pressure. The SQN FSAR further states that the basic performance requirement for the lower inlet doors for design basis accident conditions is to open rapidly and fully and to ensure proper venting of released energy into the ice condenser.

The existing 14-day action is based on long-term ice storage tests that indicate that if the temperature is maintained below 27 degrees Fahrenheit, there would not be a significant loss of ice from sublimation. This action is approprie for the condition of one or more

open doors. The condition of the irae, doors being blocked closed does not increase ice condenser temperature or increase sublimation, but rather may impact immediate ice condenser operabil4ty. With the inlet ,

doors blocked closed and not capable of automatically opening, the ice condenser may not adequately perform the safety-related function of reducing the post-LOCA and/or HELS pressure inside containment. The 1-he<ir action is consistent with the action of LCO 3.6.1.1, " Containment Integrity."

In summary, while the curr ent TS 3.6.5.3 does address inoperability of ice condenser doors, the provided action is considered inappropriately _

nonconservative for the situation of interest. As currently written, the p action would allow power operation with a significant safety system si partially or fully disabled for a period exceeding 14 days. The proposed changes more appropriately reflect the significance of the condition.

Env i ronmen_t a L_Inipa c LEyaluation The proposed change request does not involve an unreviewed environment?1 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 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, n

1. I 2. Result in a significant cro ige in ef fluents 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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5 Enclosure-3 ,

PROPOSED TECHNICAL SPECIFICATION (TS) CHANGE

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SEQUOYAH NL., LEAR PLANT UNITE 1 ANJ 2 DOCKET NOS. 50-327 AND 50-320 .

L (TVA-SQN-TS-92-04)  !

DETE' AMINATION OF NO SIGNIFICANT HAZARDS CONSIDERATION

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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 increasetin the probability or consequences of an accident previously evaluated.

The proposed changes to the existing TS 3.6.5.3 provide requirements that impose more restrictive action to be taken in the event ice condenser inlet doors are physically restreinud from opening. The proposed change does not involve or result in any alteration of plant configuration, equipment, or action that would affect accident mitigation. The ice condenser and the associated doors are utilized __

for accident mitigation and are not considered to be the source for any accident. While the actions to be taken for inoperable inlet doors have been changed, the functions of the ice condenser and the doors remain the same. Therefore, the probability or consequences of an accident previously evaluated has not been increased.

2. Create the possibility of a new or dif ferent kind of accident f rom any previously analyzed.

The ice condenser and the associated doors are utilized for accident mitigation and are not considered to be the source for any accident.

While the actions to be taken for inoperable inlet doors have been changed, the functions of the ice condenser and the doors remain the same. Therefore, no equipment postulated to create an accident is imr:cted, and the possibility of a new or different kind of accident is not increased.

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

The proposed changes do not alter the functions of any safety-related equipment. All accident mitigation functions of the ice condenser will remain the same and the proposed change will ensure appropriate action is taken in the event an ice condenser inlet door is physically re ined from opening. Therefore, a reduction in a margin of sa' is not involved as a result of the proposed change.