ML17335A368

Proposed Tech Specs,Adding New TS Re Distributed Ignition Sys

ML17335A368
Person / Time
Site:	Cook
Issue date:	12/03/1998
From:	INDIANA MICHIGAN POWER CO.
To:
Shared Package
ML17335A367	List: ML17335A366 ML17335A368
References
NUDOCS 9812080069
Download: ML17335A368 (32)

Text

ATTACHMENT 2 TO AEP:NRC:1291 CURRENT PAGES MARKED-UP TO SHOW PROPOSED AMENDMENT TO THE TECHNICAL SPECIFICATIONS DISTRIBUTED IGNITION SYSTEM 981208006'P 981203 PDR ADOCK 050003i5 '

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I

~ I INDEX.

j LIMITING CONDITIONS FOR OPERATION AND SURVEILLANCE RE UIREMENTS SECTION PAGE 3 4.5 EMERGENCY CORE COOLING SYSTEMS ECCS 3/4.5.1 ACCUMULATORS 3/4 5-1 3/4.5.2 ECCS SUBSYSTEHS - Tavg greater than or e qual o

to 350 Fe ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 3/4 5-3 3/4.5.3 ECCS SUBSYSTEMS' Tavg less than 350 F.. 3/4 5-7 3/4.5.4 BORON INJECTION SYSTEM Intentionally Left Blank 3/4 5-9 Intencionally Left Blank 3/4 5-10 3/4.5.5 REFUELING WATER STORAGE TANKS 3/4 5-11 3 4.6 CONTAINMENT SYSTE."fS 3/4.6.1 PRIMLY CONTAINMENT Concainment Integrity 3/4 6-1 Containment Leakage 3/4 6-2 Containment Air Locks.. 3/4 6-4 Internal Pressure 3/4 6-6 Air Temperature 3/4 6-7 Containmenc Structural Integrity 3/4 6-9 Contai.nment Venti.lation Systems. 3/4 6-9a 3/4. 6. 2 OEPRESSURI2ATION AND COOLING SYSTE."iS Containment Spray System. 3/4 6-10

5. ay Additive System.. 3/4 6-12 3/4.6.3 CONTAINMENT ISOLATION VALVES 3/4 6-14 3/4.6.4 COMBUSTIBLE GAS CONTROL Hydrogen Analyzers 3/4 6-23 Electric Hydrogen Recombiners - W 3/4 6-24 Sird~ia~ma'gni+io~ SySA~...... S/<

COOK'NUCLEAR PLANT - UNIT 1 VII AMENDMENT No. gl, Sit XN,15S

3.6.4.2 Two independent containment hydrogen recombiner systems shall be OPERABLE.

MODES 1 and 2.*

hQXlQE-Vfth one hydrogen recombfner syseem fnoperable, reseore che inoperable syseem eo OPERABLE status within 30 days or be fn at least HOT STANDBY withfxt'Che nexe 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.

4.6.4.2 Each hydrogen recombfner syseem shall be demonstrated OPERABLE:

a. At least once per 18 months by verifying during a recombiner system funceional 0

test thae the minimum heater sheath temperature increases to x 700 P within 90 minutes and is maintained for ae lease 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />.

b. Ae lease once per 18 months by:

PerfoxELLGg.a QfhNNEF CALIBRATION of .all recombfner fnsCreaentation and

. 'conerol "cfrcuf ts.'erf fyfng through a vfsual eximfnatfon chat there fs. no evfdence abnormal conditions within the recombfners (f.e., loose wiring or structural'connections, deposits of forefgn miterfals, etc.)

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3/4 LIMITINGCONiDITIONS FOR OPERATION AND SURVEILLANCE REQUIREMENTS 3/4.6 CONTAINiiIENTSYSTEMS Verifying during a rccombiner system functional test that the heater sheath temperature increases to ~ 1200'F within 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> and is maintained for at least 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.

Verifying the integrity of all heater electrical circuits by performing a continuity and resistance to ground test following the above required functional test. The resistance to ground for any heater phase shall be 2 10,000 ohms.

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~ uuV~ ra Wage QC@urrZEmaurg f H~+ Z DISTRIBUTED IGNITION SYSTEM LIMITINGCONDITION FOR OPERATION 3.6.4.3 Both trains of the Distributed Ignition System shall be OPERABLE.

APPLICABILITY: MODES 1 a11d 2.

ACTION:

With one train of the Distributed Ignition System inoperable:

Restore the inoperable train to OPERABLE status within 7 days, or

b. Perform surveillance requirement 4.6.4.3a once per 7 days on the OPERABLE train until the inoperable train is restored to OPERABLE status.

With no OPERABLE hydrogen igniter in one containment region, restore one hydrogen igniter in the affected containment region to OPERABLE status within 7 days, or be in HOT STANDBY within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.

SURVEILLANCE RE UIREMENTS 4.6.4.3 Each train of the Distributed Ignition System shall be demonstrated OPERABLE:

a. Once per 92 days by energizing the supply breakers and verifying that at least 34 of 35 igniters are energized.

b. Once per 92 days, verify at least one hydrogen igniter is OPERABLE in each containment region.

c. Once per 18 months by verifying the temperature of each igniter is a minimum 1700'F.

COOK NUCLEAR PLANT-UMT 1 Page 3/4 6-25 AMEND ME 223

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3/4 BASES 3/4.6 COilTAINMENT SYSTEMS 3/4.6.2 DEPRESSURIZATION AND COOLING SYSTEMS 3/4.6.2.1 CONTAINMENT SPRAY SYSTEiVI The OPERABILITY of the containment spray system ensures that containment depressurization and cooling capability will be available in the event of a LOCA. The pressure reduction and resultant lower containment leakage rate are consistent with the assumptions used in the accident analyses.

3/4.6.2.2 SPRAY ADDITIVE SYSTEM The OPERABILITY of the spray additive system ensures that sufficient NaOH is added to the containment spray in the event of a LOCA. The limits on NaOH minimum volume and concentration, ensure that I) the iodine removal efficiency of the spray water is maintained because of the increase in pH value, and 2) corrosion effects on components within containment are minimized. These assumptions are consistent with the iodine removal efficiency assumed in the accident analyses.

3/4.6.3 CONTAINMENT ISOLATION VALVES The OPERABILITY of the containment isolation valves ensures that the containment atmosphere will be isolated from the outside environment in the event'f a release of radioactive material to the containment atmosphere or pressurization of the containment. Containment isolation within the time limits specified ensures that the release of radioactive material to the environment will be consistent with the assumptions used in the analyses for a LOCA.

The opening of containment purge and exhaust valves and locked . sealed closed containment isolation valves on an intermittent basis under administrative control includes the following considerations: (I) stanoning a qualified individual, who is in constant communication with control room, at the valve controls, (2) instructing this individual to close these valves in an accident situation, and (3) assuring that environmental conditions will not preclude access to close the valves and that this action will prevent the release of radioactivity outside the containment.

3/4.6.4 COMBUSTIBLE GAS CONTROL The OPERABILITY of the equipment and systems required for the detection and control of hydrogen gas ensures that this equipment will be available to maintain the hydrogen concentration within containment below its flammable limit during post-LOCA conditions. Either recombiner unit is capable of controlling the expected hydrogen generation associated with: I) zirconium-water reactions; 2) radiolytic decomposition of water; and 3) corrosion of metals within containment.

The acceptance criterion of 10,000 ohms is based on the test being performed with the heater element at an ambient temperature, but can be conservatively applied when the element is at a temperature above ambient.

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Distributed Ignition System (DIS)

The DIS permits controlled burning of the excessive hydrogen generated during degraded core LOCAs postulated by 10CFR50.44 "Standards for combustible gas control system in light-water-cooled power reactors." The postulated amount of hydrogen is equivalent to that generated from the reaction of 75% of the fuel cladding with water. Controlled burning at low hydrogen concentrations precludes containment damage that could result from random ignition at high concentrations. An extensive program of testing and analysis has demonstrated that a system of strategically placed hydrogen igniters (the DIS) can be relied upon for controlled burns of the hydrogen gas postulated for degraded cores. Furthermore, it has been shown that this can be accomplished at combustion temperatures and pressures that willnot challenge the integrity of the containment structure or the operability of containment equipment necessary to shutdown (and maintain shutdown) the reactor.

The hydrogen igniters are not included for mitigation of a Design Basis Accident (DBA) because an amount of hydrogen equivalent to that generated from the reaction of 75% of the fuel cladding with water is far in excess of the hydrogen calculated for the limiting DBA loss of coolant accident (LOCA). The hydrogen concentration resulting from a DBA can be maintained less than the flammability. limit using the hydrogen recombiners.

The DIS consists of two independent trains of 35 igniters located throughout containmcnt. The igniters in each train are further divided into six groups per train powered from different phases of two separate three phase transformers. It is the transformer phase that uniquely defines a group.

Operation in Modes 1 and 2 with both trains available ensures the capability for controlled burning of hydrogen gas inside containment during degraded core LOCA events.

In Modes 3 and 4 both the hydrogen production rate and the total hydrogen production afler a LOCA would be significantly less than that calculated for the DBA LOCA. Also, because of the limited time in these MODES, the probability of an accident requiring the DIS is low. Therefore the DIS is not required in Modes 3 and 4.

In Modes 5 and 6, the probability and consequences of a LOCA are reduced due to the pressure and temperature limitations of these Modes. Therefore, the DIS is not required to be OPERABLE in Modes 5 and 6.

The 7 day Completion Time for restoration of an inoperable DIS train in Modes 1 or 2 is based on the low probability of occurrence of a degraded core event that would generate hydrogen in amounts equivalent to a metal water reaction of 75% of the core cladding and the low probability of failure of the OPERABLE DIS train. This justification also applies to the 7 day Completion Time allowed for redundant igniters being inoperable in the same containment region. For this case there would also be ignition capability from adjacent containment regions by flame propagation to the region with no OPERABLE igniters.

Confidence in system OPERABILITYis demonstrated by surveillance testing. Since many igniters are inaccessible at power, surveillance testing in Mode 1 is limited to measurement of igniter current when the DIS is energized by groups. Measured currents are compared with baseline data for the group.

Igniter temperature measurements for all igniters can only be performed during shutdown and is performed every 18 months. This testing energizes all igniters and confirms the ability of each igniter to obtain a surface temperature of at least 1700'F. This temperature is conservatively above the temperature necessary to ignite hydrogen mixtures at concentrations near the lower flammability limit. Test experience indicates that individual igniter failures are generally total failures and do not involve the inability to reach the required temperature when an igniter is drawing normal amperage. This observed failure mode provides reasonable confidence that an igniter failing to reach the required temperature would also be detected by reduced group current measurements during the Mode 1 surveillances. Therefore the 18 month frequency for actual temperature measurements is acceptable.

INDEX LIMITINC CONDITIONS FOR OPERATION AND SURVEILLANCE UIRBQBiTS SECTION PhCE 3 4.5 EMERCENCY CORE COOLINC SYSTEMS ECCS 4

'E I I4 cC ] AC CUMUKATORS ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ i ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ s ~ ~ ~ ~ s ~ ~ ~ 3/4 5-1 3/4,5.2 ECCS SUbSYSTEMS - Tave greater than orequal to 350 F. 3/4 5 3 3/4.5.3 ECCS SUbSYSTEMS - Tave leea chan 350 F ......... 3/4 5-7 3/4.5.4 bORON IHJECTION SYSTEM Intentionally Left blank............. 3/4 5 9 Intentionally Left blank..... 3/4 5-10 3/4. 5. 5 REFUELINC VATER STORAGE TANK .... ~ * ~ ~ 3/4 5-11 3 4.6 CONThINMENT SYSTEMS 3/4. 6. 1 PRIMARY CONTAINMENT Containaent Integrity ~ ~ 4 ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 3/4 6-1 Containment Leakage>> 3/4 6-2 Conte izcNnt Air Locks ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ i ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 3/4 6-4 Internal Preeaure. ~ s ~ s ~ s ~ ~ ~ s ~ ~ ~ ~ ~ ii ~ ~ i ~ ~ ~ ~ ~ ~ ~ 3/4 6-6 hir Temperature . 3/4 6-7 Concainlent Struccural Integrity . 3/4 6-9 Concainaenc Ventilation Syecea......................,.. 3/4 6-9a 3/4.6.2 DEPRESSURIZATION AND COOLINC SYSTEMS Containlent Spray Syetaa 0 ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 3/4 6-10 Spray Additive Syacea . 3/4 6-11 3/4.6.3 CONTAIHMEHT ISOIATIOH VALVES 3/4 6-13 3/4.6.4 COMbUSTIbLE CAS COHTML Hydropn hnalyrer ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 3/4 6-33 Electric Hydrogen Recoabinere - W...................... 3/4 6-34 COOK NUCLEAR PLANT - UNIT 2 VII AMZgleENT NO. I~. ~<>, 142

INDEX BASES SECTION .~ PAGE 3/4.4 REACTOR COOLANT SYSTEM Continued 3/4.4.9 PRESSURE/TEMPERATURE LIMITS . B 3/4 4-6 3/4.4.10 STRUCTURAL INTEGRITY B 3/4 4-10 3/4.4.11 RELIEF VALVES .. B 3/4 4-11 3/4.4.12 REACTOR COOLANT VENT SYSTEM B 3/4 4-11 3/4.5 EMERGENCY CORE COOLING SYSTEMS ECCS 3/4.5.1 ACCUMULATORS B 3/4 5-1 3/4.5.2 and 3/4.5.3 ECCS SUBSYSTEMS B 3/4 5-1 3/4.5.4 BORON INJECTION SYSTEM B 3/4 5-2 3/4.5.5 REFUELING WATER STORAGE TANK (RWST) . B 3/4 5-3 3/4.6 CONTAINMENTSYSTEMS PRIMARY CONTAINMENT '.4.6.1 B 3/4 6-1 3/4.6.2 DEPRESSURIZATION AND COOLING SYSTEMS . B 3/4 6-3 3/4.6.3 CONTAINMENT ISOLATION VALVES 3/4.6.4 COMBUSTIBLE GAS CONTROL'/4.6.5 ICE CONDENSER 3/4.7 PLANT SYSTEMS 3/4.7.1 TURBINE CYCLE B 3/4 7-1 3/4.7.2 STEAM GENERATOR PRESSURE/1'EMPERATURE LIMITATION ....... B 3/4 74 3/4.7.3 COMPONENT COOLING WATER SYSTEM B 3/4 74 3/4.7.4 ESSENTIAL SERVICE WATER SYSTEM... " ~ .. B 3/4 74 3/4.7.5 CONTROL ROOM EMERGENCY VENTILATIONSYSTEM ........... B 3/4 74a 3/4.7.6 ESF VENTILATIONSYSTEM .. B 3/4 7-5 3/4.7.7 HYDRAULICSNUBBERS B 3/4 7-5 COOK NUCLEAR PLANT-UNIT2 AMENDMENT407, 4$ 6,

3/4 LIMITINGCONDITIONS FOR OPERATION AND SURVEILLAiICE REQUIREtWIENTS 3/4.6 CONTAINMENTSYSTEMS DISTRIBUTED IGNITION SYSTEM LIMITINGCONDITION FOR OPERATION 3.6.4.3 Both trains of the Distributed Ignition System shall be OPERABLE.

APPLICABILITY: MODES 1 and 2.

ACTION:

With one train of the Distributed Ignition System inoperable:

Restore the inoperable train to OPERABLE status within 7 days, or Perform surveillance requirement 4.6.4.3a once per 7 days on the OPERABLE train until the inoperable train is restored to OPERABLE status.

With no OPERABLE hydrogen igniter in one containment region, restore one hydrogen igniter in the affected containment region to OPERABLE status within 7 days, or be in HOT STANDBY within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.

SURVEILLANCE RE UIREMENTS 4.6.4.3 Each train of the Distributed Ignition System shall be demonstrated OPERABLE:

Once per 92 days by energizing the supply breakers and verifying that at least 34 of 35 igniters are energized.

Once per 92 days, verify at least one hydrogen igniter is OPERABLE in each containment region.

Once per Ig months by verifying the temperature of each igniter is a minimum 1700'F.

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COOK NUCLEAR PLANT-UNIT2 Page 3/4 6-34a

3/4 BASES 3/4.6 CONTAINMENT SYSTEM IS 3/4 6.4 COMBUSTIBLE GAS CONTROL The OPERABILITY of the equipment and systems required for the detection and control of hydrogen gas ensures that this equipment will be available to maintain the hydrogen concentration within containment below its flammable limit during post-LOCA conditions. Either recombiner unit is capable of controlling the expected hydrogen generation associated with: I)'zirconium-water reactions; 2) radiolytic decomposition of water; and 3) corrosion of metals wittun containment. These hydrogen control systems are consistent with the recommendations of Regulatory Guide 1.7, "Control of Combustible Gas Concentrations in Containment Following a LOCA," March 1971.'he acceptance criterion of 10,000 ohms is based on the test being performed with the heater element at an ambient temperature, but can be conservatively applied when the heater element is at a temperature above ambient.

3/4.6.5 ICE CONDENSER The requirements associated with each of the components of the ice condenser ensure that the overall system will be available to provide sufficient pressure suppression capability to limit the containment peak pressure transient to less than 12 psig during LOCA conditions.

3/4.6.5.1 ICE BED The OPERABILITY of the ice bed ensures that the required ice inventory will 1) be distributed evenly through the containment bays, 2) contain sufficient boron to preclude dilution of the containment sump following the LOCA and

3) contain sufficient heat removal capability to condense the reactor system volume released during a LOCA. These conditions are consistent with the assumptions used in the accident analyses.

The minimum weight figure of 1333 pounds of ice per basket contains a 5% conservative allowance for ice loss through sublimation. In the event that observed sublimation rates are equal to or lower than design predictions after, g',>%i!I 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 18 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 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 provide assurance that the ice bed heat removal capacity will be retained within the speciifiied time limits.

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Distributed Ignition System (DIS)

The DIS permits controlled burning of the excessive hydrogen generated during degraded core LOCAs postulated by 10CFR50.44 "Standards for combustible gas control system in light-water-cooled power reactors." The postulated amount of hydrogen is equivalent to that generated from the reaction of 75'/o of the fuel cladding with water. Controlled burning at low hydrogen concentrations precludes containment damage that could result from random ignition at high concentrations. An extensive program of testing and analysis has demonstrated that a system of strategically placed hydrogen igniters (the DIS) can be relied upon for controlled burns of the hydrogen gas postulated for degraded cores. Furthermore, it has been shown that this can be accomplished at combustion temperatures and pressures that willnot challenge the integrity of the containment structure or the operability of containment equipment necessary to shutdown (and maintain shutdown) the reactor.

The hydrogen igniters are not included for mitigation of a Design Basis Accident (DBA) because an amount of hydrogen equivalent to that generated from the reaction of 75~/o of the fuel cladding with water is far in excess of the hydrogen calculated for the limiting DBA loss of coolant accident (LOCA). The hydrogen concentration resulting from a DBA can be maintained less than the flammability limit using the hydrogen recombiners.

The DIS consists of two independent trains of 35 igniters located throughout containmcnt. The igniters in each train are further divided into six groups per train powered from different phases of two separate three phase transformers. It is the transformer phase that uniquely defines a group.

Operation in Modes 1 and 2 with both trains available ensures the capability for controlled burning of hydrogen gas inside containment during degraded core LOCA events.

I In Modes 3 and 4 both the hydrogen production rate and the total hydrogen production afler a LOCA would be significantly less than that calculated for the DBA LOCA. Also, because of the limited time in these MODES, the probability of an accident requiring the DIS is low. Therefore the DIS is not required in Modes 3 and 4.

In Modes 5 and 6, the probability and consequences of a LOCA are reduced due to the pressure and temperature limitations of these Modes. Therefore, the DIS is not required to be OPERABLE in Modes 5 and 6.

The 7 day Completion Time for restoration of an inoperable DIS train in Modes 1 or 2 is based on the low probability of occurrence of a degraded core event that would generate hydrogen in amounts equivalent to a metal water reaction of 75~/o of the core cladding and the low probability of failure of the OPERABLE DIS train. This justification also applies to the 7 day Completion Time allowed for redundant igniters being inoperable in the same containment region. For this case there would also be ignition capability from adjacent containment regions by flame propagation to the region with no OPERABLE igniters.

Confidence in system OPERABILITYis demonstrated by surveillance testing. Since many igniters are inaccessible at power, surveillance testing in Mode 1 is limited to measurement of igniter current when the DIS is energized by groups. Measured currents are compared with baseline data for the group.

Igniter temperature measurements for all igniters can only be performed during shutdown and is performed every 18 months. This testing energizes all igniters and confirms the ability of each igniter to obtain a surface temperature of at least 1700'F. This temperature is conservatively above the temperature necessary to ignite hydrogen mixtures at concentrations near the lower flammability limit. Test experience indicates that individual igniter failures are generally total failures and do not involve the inability to reach the required temperature when an igniter is drawing normal amperage. This observed failure mode provides reasonable confidence that an igniter failing to reach the required temperature would also be detected by reduced group current measurements during the Mode 1 surveillances. Therefore the 18 month frequency for actual temperature measurements is acceptable.

ATTACHMENT 3 TO AEP:NRC:1291 PROPOSED AMENDMENT TO THE TECHNICAL SPECIFICATIONS DISTRIBUTED IGNITION SYSTEM

I UNIT 1 INDEX LIMITINGCONDITIONS FOR OPERATION AND SURVEILLANCE REQUIREMENTS SECTION PAGE 3/4.5 EMERGENCY CORE COOLING SYSTEMS ECCS 3/4;5".1 ACCUMUL'ATORS 3/4 5-1 3/4.5.2 ECCS SUBSYSTEMS -Tavg greater than or equal to 350'F .. 3/4 5-3 3/4.5.3 ECCS SUBSYSTEMS - Tavg less than 350'F 3/4 5-7 3/4.5.4 BORON INJECTION SYSTEM Intentionally Left Blank 3/4 5-9 Intentionally Left Blank 3/4 5-10 3/4.5.5 REFUELING WATER STORAGE TANK 3/4 5-11 3/4:6 CONTAINMENTSYSTEMS 3/4.6.1 PRIMARY CONTAINMENT Containment Integrity 3/4 6-1 Containment-Leakage -........ 3/4 6-2 Containment Air Locks 3/4 64 Internal Pressure 3/4 6-6 Air Temperature 3/4 6-7 Containment Structural Integrity 3/4 6-9 Containment Ventilation Systems . 3/4 6-9a 3/4.6.2 . DEPRESSURIZATION AND COOLING SYSTEMS Containment Spray System 3/4 6-10 Spray Additive System 3/4 6-12 3/4.6.3 CONTAINMENT ISOLATION VALVES 3/4 6-14 3/4.6.4 COMBUSTIBLE GAS CONTROL Hydrogen Analyzers . 3/4 6-23 Electric Hydrogen Recombiners - W 3/4 6-24 Distributed Ignition System 3/4 6-25 COOING NUCLEAR PLANT-UNIT 1 VII AMENDMENTQR, 36, k%) AS,

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3/4 LIMITINGCONDITIONS FOR OPERATION AND SURVEILLANCEREQUIREMENTS 3/4.6 CONTAINMENTSYSTEMS ELECTRIC HYDROGEN RECOMBINERS - W LIMITINGCONDITION FOR OPERATION 3.6.4.2 Two independent containment hydrogen recombiner systems shall be OPERABLE.

APPLICABILITY: MODES 1 and 2.

ACTION:

I With one hydrogen recombiner system inoperable, restore the inoperable system to OPERABLE status within 30 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 />.

SURVEILLANCE RE UIREMENTS 4.6.4.2 Each hydrogen recombiner system shall be demonstrated OPERABLE:

At least once per 18 months by verifying during a recombiner system functional test that the minimum heater sheath temperature increases to 2 700'F within 90 minutes and is maintained for at least 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />.

b. At least once per 18 months by:

1. Performing a CHANNEL CALIBRATION of all recombiner instrumentation and control circuits.

2. Verifying through a visual examination that there is no evidence of abnormal conditions within the recombiners (i.e., loose wiring or structural connections, deposits of foreign materials, etc.)

Verifying during a recombiner system functional test that the heater sheath temperature increases to 2 1200'F within 5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> and is maintained for at least 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.

4, Verifying the integrity of all heater electrical circuits by performing a continuity and resistance to ground test following the above required functional test. The resistance to ground for any heater phase shall be R 10,000 ohms.

COOK NUCLEAR PLANT-UNIT 1 Page 3/4 6-24 AMENDMENT4Q, R2S,

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LIMITINGCONDITIONS FOR OPERATION AND SURVEILLANCEREQUIREMENTS t

3/4.6 CONTAINMENTSYSTEMS DISTRIBUTED IGNITION SYSTEM LIMITINGCONDITION FOR OPERATION 3.6.4.3 Both trains of the Distributed Ignition System shall be OPERABLE.

APPLICABILITY: MODES 1 and 2.

ACTION:

With one train of the Distributed Ignition System inoperable:

a. Restore the inoperable train to OPERABLE status within 7 days, or

b. Perform surveillance requirement 4.6.4.3a once per 7 days on the OPERABLE train until the inoperable train is restored to OPERABLE status.

With no OPERABLE hydrogen igniter in one containment region, restore one hydrogen igniter in the affected containment region to OPERABLE status within 7 days, or be in HOT STANDBY within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.

SURVEILLANCE RE UIREMENTS 4.6.4.3 Each train of the Distributed Ignition System shall be demonstrated OPERABLE:

ao Once per 92 days by energizing the supply breakers and verifying that at least 34 of 35 igniters are energized,

b. Once per 92 days, verify at least one hydrogen igniter is OPERABLE in each containment region.

C. Once per 18 months by verifying the temperature of each igniter'is a minimum 1700'F.

COOK NUCLEAR PLANT-UNIT1 Page 3/4 6-25

3/4 BASES 3/4.6 CONTAINMENT SYSTEMS 3/4.6.2 DEPRESSURIZATION AND COOLING SYSTEMS 3/4.6.2.1 CONTAINMENT SPRAY SYSTEM The OPERABILITY of the containment spray system ensures that containment depressurization and cooling capability will be available in the event of a LOCA. The pressure reduction and resultant lower containment leakage rate are consistent with the assumptions used in the accident analyses.

3/4.6.2.2 SPRAY ADDITIVE SYSTEM The OPERABILITY of the spray additive system ensures that sufficient NaOH is added to the containment spray in the event of a LOCA. The limits on NaOH minimum volume and concentration, ensure that 1) the iodine removal efficiency of the spray water is maintained because of the increase in pH value, and 2) corrosion effects on components within containment are minimized. These assumptions are consistent with the iodine removal efficiency assumed in the accident analyses.

3/4.6.3 CONTAINMENT ISOLATION VALVES The OPERABILITY of the containment isolation valves ensures that the containment atmosphere will be isolated from the outside environment in the event of a release of radioactive material to the containment atmosphere or pressurization of the containment. Containment isolation within the time limits specified ensures that the release of radioactive material to the environment will be consistent with the assumptions used in the analyses for a LOCA.

The opening of containment purge and exhaust valves and locked or sealed closed containment isolation valves on an intermittent basis under administrative control includes the following considerations: (1) stationing a qualified individual, who is in constant communication with control room, at the valve controls, (2) instructing this individual to close these valves in an accident situation, and (3) assuring that environmental conditions will not preclude access to close the valves and that this action will prevent the release of radioactivity outside the containment.

3/4.6.4 COMBUSTIBLE GAS CONTROL Hydrogen Analyzers and Recombiners The OPERABILITY of the equipment and systems required for the detection and control of hydrogen gas ensures that this equipment will be available to maintain the hydrogen concentration within containment below its flammable limit during post-LOCA conditions. Either recombiner unit is capable of controlling the expected hydrogen generation associated with 1) zirconium-water reactions, 2) radiolytic decomposition of water and 3) corrosion of metals within containment.

The acceptance criteria of 10,000 ohms is based on the test being performed with the heater element at an ambient temperature, but can be conservatively applied when the heater element is at a temperature above ambient.

Distributed Ignition System (DIS)

The DIS permits controlled burning of the excessive hydrogen generated during degraded core LOCAs postulated by 10CFR50.44, "Standards for combustible gas control system in light-water-cooled power reactors." The postulated amount of hydrogen is equivalent to that generated from the reaction of 75% of the fuel cladding with water.

ControHed burning at low hydrogen concentrations precludes containment damage that could result from random ignition at high concentrations. An extensive program of testing and analysis has demonstrated that a system of strategically placed hydrogen igniters (the DIS) can be relied upon for controlled burns of the hydrogen gas postulated COOK NUCLEAR PLANT-UNIT 1 Page B 3/4 6-3 AMENDMENT 4R, ~,

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3/4 BASES 3/4.6 CONTAINMENT SYSTEMS 3/4.6.4 COMBUSTIBLE GAS CONTROL continued for degraded cores. Furthermore, it has been shown that this can be accomplished at combustion temperatures and pressures that willnot challenge the integrity of the containment structure or the operability of containment equipment necessary to shutdown (and maintain shutdown) the reactor.

The hydrogen igniters are not included for mitigation of a Design Basis Accident (DBA) because an amount of hydrogen equivalent to that generated from the reaction of 75% of the fuel cladding with water is far in excess of the hydrogen calculated for the limiting DBA loss of coolant accident (LOCA). The hydrogen concentration resulting from a DBA can be maintained less than the flammability limit using the hydrogen recombiners.

The DIS consists of two independent trains of 35 igniters located throughout containment. The igniters in each train are further divided into six groups per train powered from different phases of two separate three phase transformers.

It is the transformer phase that uniquely defines a group.

Operation in MODES 1 and 2 with both trains available ensures the capability for controlled burning of hydrogen gas inside containment during degraded core LOCA events.

In MODES 3 and 4 both the hydrogen production rate and the total hydrogen production after a LOCA would be significantly less than that calculated for the DBA LOCA. Also, because of the limited time in these MODES, the probability of an accident requiring the DIS is low. Therefore the DIS is not required in MODES 3 and 4.

In MODES 5 and 6, the probability and consequences of a LOCA are reduced due to the pressure and temperature limitations of these MODES. Therefore, the DIS is not required to be OPERABLE in MODES 5 and 6.

The 7 day Completion Time for restoration of an inoperable DIS train in MODES 1 or 2 is based on the low probability of occurrence of a degraded core event that would generate hydrogen in amounts equivalent to a metal water reaction of 75% of the core cladding and the low probability of failure of the OPERABLE DIS train. This justification also applies to the 7 day Completion Time allowed for redundant igniters being inoperable in the same containment region. For this case there would also be ignition capability from adjacent containment regions by flame propagation to the region with no OPERABLE igniters.

Confidence in system OPERABILITY is demonstrated by surveillance testing. Since many igniters are inaccessible at power, surveillance testing in MODE 1 is limited to measurement of igniter current when the DIS is energized by groups. Measured currents are compared with baseline data for the group.

Igniter temperature measurements for all igniters can only be performed during shutdown and is performed every 18 months. This testing energizes all igniters and confirms the ability of each igniter to obtain a surface temperature of at least 1700'F. This temperature is conservatively above the temperature necessary to ignite hydrogen mixtures at concentrations near the lower flammability limit. Test experience indicates that individual igniter failures are generally total failures and do not involve the inability to reach the required temperature when an igniter is drawing normal amperage. This observed failure mode provides reasonable confidence that an igniter failing to reach the required temperature would also be detected by reduced group current measurements during the MODE 1 surveillances.

Therefore the 18 month frequency for actual temperature measurements is acceptable.

COOK NUCLEAR PLANT-UNIT 1 Page B 3/4 6-3a

0 INDEX LIMITINGCONDITIONS FOR OPERATION AND SURVEILLANCE REQUIREMENTS SECTION PAGE 3/4.5 EMERGENCY CORE COOLING SYSTEMS ECCS 3/4.5.1 ACCUMULATORS 3/4 5-1 3/4.5.2 ECCS SUBSYSTEMS - Tavg greater than or equal to 350'F .. 3/4 5-3 3/4.5.3 ECCS SUBSYSTEMS - Tavg less than 350'F 3/4 5-7 3/4.5.4 BORON INJECTION SYSTEM Intentionally Left Blank 3/4 5-9 Intentionally Left Blank 3/4 5-10 3/4.5.5 REFUELING WATER STORAGE TANK 3/4 5-11 3/4.6 CONTAINMENTSYSTEMS 3/4.6.1 PRIMARY CONTAINMENT Containment Integrity 3/4 6-1 Containment Leakage 3/4 6-2 Containment Air Locks 3/4 6P Internal Pressure 3/4 6-6 Air Temperature 3/4 6-7 Containment Structural Integrity 3/4 6-9 Containment Ventilation System 3/4 6-9a 3/4.6.2 DEPRESSURIZATION AND COOLING SYSTEMS Containment Spray System 3/4 6-10 Spray Additive System 3/4 6-11 3/4.6.3 CONTAINMENT ISOLATION VALVES 3/4 6-13 3/4.6.4 COMBUSTIBLE GAS CONTROL Hydrogen Analyzer .. 3/4 6-33 Electric Hydrogen Recom(iners - W 3/4 6-34 Distributed Ignition System 3/4 6-34a COOK NUCLEAR PLANT-UNIT2 AMENDMENT48, QQ, 445,

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INDEX BASES SECTION PAGE 3/4.4 REACTOR COOLANT SYSTEM Continued 3/4.4.9 PRESSURE/TEMPERATURE LIMITS B 3/4 4-6 3/4.4.10 STRUCTURAL INTEGRITY B 3/4 4-10 3/4.4.11 RELIEF VALVES .. B 3/4 4-11 3/4.4.12 REACTOR COOLANT VENT SYSTEM B 3/4 4-11 3/4.5 EMERGENCY CORE COOLING SYSTEMS ECCS 3/4.5.1 ACCUMULATORS B 3/4 5-1 3/4.5.2 and 3/4.5.3 ECCS SUBSYSTEMS B 3/4 5-1 3/4.5.4 BORON INJECTION SYSTEM .. B 3/4 5-2 3/4.5.5 REFUELING WATER STORAGE TANK (RWST) .. B 3/4 5-3 3/4.6 CONTAINMENT SYSTEMS 3.4.6.1 PRIMARY CONTAINMENT B 3/4 6-1 3/4.6.2 DEPRESSURIZATION AND COOLING SYSTEMS B 3/4 6-3 3/4.6.3 CONTAINMENT ISOLATION VALVES B 3/4 6-3 3/4.6.4 COMBUSTIBLE GAS CONTROL .... B 3/4 64 3/4.6.5 ICE CONDENSER B 3/4 64a 3/4.7 PLANT SYSTEMS 3/4.7.1 TURBINE CYCLE B 3/4 7-1 3/4.7.2 STEAM GENERATOR PRESSURE/TEMPERATURE LIMITATION B 3/4 7-4 3/4.7.3 COMPONENT COOLING WATER SYSTEM B 3/4 74 3/4.7.4 ESSENTIAL SERVICE WATER SYSTEM .. B 3/4 7-4 3/4:7.5 CONTROL ROOM EMERGENCY VENTILATIONSYSTEM B 3/4 74a 3/4.7.6 ESF VENTILATIONSYSTEM . B 3/4 7-5 3/4.7.7 HYDRAULICSNUBBERS B 3/4 7-5 COOK NUCLEAR PLANT-UNIT2 XII AMENDMENT4P, 4', IVY,

3/4 LIMITINGCONDITIONS FOR OPERATION AND SURVEILLANCE REQUIREMENTS 3/4.6 CONTAINMENTSYSTEMS DISTRIBUTED IGNITION SYSTEM LIMITINGCONDITION FOR OPERATION 3.6.4.3 Both trains of the Distributed Ignition System shall be OPERABLE.

APPLICABILITY: MODES 1 and 2.

ACTION:

With one train of the Distributed Ignition System inoperable:

Restore the inoperable train to OPERABLE status within 7 days, or Perform surveillance requirement 4.6.4.3a once per 7 days on the OPERABLE train until the inoperable train is restored to OPERABLE status.

With no OPERABLE hydrogen igniter in one containment region, restore one hydrogen igniter in the affected containment region to OPERABLE status within 7 days, or be in HOT STANDBY within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.

SURVEILLANCE RE UIREMENTS 4.6.4.3 Each train of the Distributed Ignition System shall be demonstrated OPERABLE:

Once per 92 days by energizing the supply breakers and verifying that at least 34 of 35 igniters are energized.

Once per 92 days, verify at least one hydrogen igniter is OPERABLE in each containment region.

Once per-18 months by verifying the temperature of each igniter is a minimum 1700'F.

COOK NUCLEAR PLANT-UNIT2 Page 3/4 6-34a AMENDMENT

3/4 'ASES 3/4.6 CONTAINMENT SYSTEMS 3/4.6.4 COMBUSTIBLE GAS CONTROL Hydrogen Analyzers and Recombiners The OPERABILITY of the equipment and systems required for the detection and control of hydrogen gas ensures that this equipment will be available to maintain the hydrogen concentration within containment below its flammable limit during post-LOCA conditions. Either recombiner unit is capable of controlling the expected hydrogen generation associated with 1) zirconium-water reactions, 2) radiolytic decomposition of water and 3) corrosion of metals within containment. These hydrogen control systems are consistent with the recommendations of Regulatory Guide 1.7, "Control of Combustible Gas Concentrations in Containment Following a LOCA," March 1971.

The acceptance criterion of 10,000 ohms is based on the test being performed with the heater element at an ambient temperature, but can be conservatively applied when the heater element is at a temperature above ambient.

Distributed Ignition System (DIS)

The DIS permits controlled burning of the excessive hydrogen generated during degraded core LOCAs postulated by 10CFR50.44, "Standards for combustible gas control system in light-waterwooled power reactors." The postulated amount of hydrogen is equivalent to that generated from the reaction of 75% of the fuel cladding with water.

Controlled burning at low hydrogen concentrations precludes containment damage that could result from random ignition at high concentrations. An extensive program of testing and analysis has demonstrated that a system of strategically placed hydrogen igniters (the DIS) can be relied upon for controlled burns of the hydrogen gas postulated for degraded cores. Furthermore, it has been shown that this can be accomplished at combustion temperatures and pressures that will not challenge the integrity of the containment structure or the operability of containment equipment necessary to shutdown (and maintain shutdown) the reactor.

The hydrogen igniters are not included for mitigation of a Design Basis Accident (DBA) because an amount of hydrogen equivalent to that generated from the reaction of 75% of the fuel cladding with water is far in excess of the hydrogen calculated for the limiting DBA loss of coolant accident (LOCA). The hydrogen concentration resulting from a DBA can be maintained less than the flammability limit using the hydrogen recombiners.

The DIS consists of two independent trains of 35 igniters located throughout containment. The igniters in each train are further divided into six groups per train powered from different phases of two separate three phase transformers.

It is the transformer phase that uniquely defines a group.

Operation in MODES 1 and 2 with both trains available ensures the capability for controlled burning of hydrogen gas inside containment during degraded core LOCA events.

In MODES 3 and 4 both the hydrogen production rate and the total hydrogen production after a LOCA would be significantly less than that calculated for the DBA LOCA. Also, because of the limited time in these MODES, the probability of an accident requiring the DIS is low. Therefore the DIS is not required in MODES 3 and 4.

In MODES 5 and 6, the probability and consequences of a LOCA are reduced due to the pressure and temperature limitations of these MODES. Therefore, the DIS is not required to be OPERABLE in MODES 5 and 6.

The 7 day Completion Time for restoration of an inoperable DIS train in MODES 1 or 2 is based on the low probability of occurrence of a degraded core event that would generate hydrogen in amounts equivalent to a metal water reaction of 75% of the core cladding and the low probability of failure of the OPERABLE DIS train. This justification also applies to the 7 day Completion Time allowed for redundant igniters being inoperable in the same COOK NUCLEAR PLANT-UNIT 2 Page B 3/4 M AMENDMENT Q%,

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3/4 BASES 3/4.6 CONTAINMENT SYSTEMS 3/4.f~.4 COMBUSTIBLE GAS CONTROL continued containment region. For this case there would also be ignition capability from adjacent containment regions by flame propagation to the region with no OPERABLE igniters.

Confidence in system OPERABILITY is demonstrated by surveillance testing. Since many igniters are inaccessible at power, surveillance testing in MODE 1 is limited to measurement of igniter current when the DIS is energized by groups. Measured currents are compared with baseline data for the group.

Igniter temperature measurements for all igniters can only be performed during shutdown and i5 performed every 18 months. Thisitesting energizes all igniters and confirms the ability of each igniter to obtain a surface temperature of at least 1700'F. This temperature is conservatively above the temperature necessary to ignite hydrogen mixtures at concentrations near the lower flammability limit. Test experience indicates that individual igniter failures are generally total failures and do not involve the inability to reach the required temperature when an igniter is drawing normal amperage. This observed failure mode provides reasonable confidence that an igniter failing to reach the required temperature would also be detected by reduced group current measurements during the MODE 1 surveillances.

Therefore the 18 month frequency for actual temperature measurements is acceptable.

3/4.6.5 ICE CONDENSER The requirements associated with each of the components of the ice condenser ensure that the overall system will be available to provide sufficient pressure suppression capability to limit the containment peak pressure transient to less than 12 psig during LOCA conditions.

3/4.6.5.1 ICE BED The OPERABILITY of the ice bed ensures that the required ice inventory will 1) be distributed evenly through the containment bays, 2) contain sufficient boron to preclude dilution of the containment sump following the LOCA and

3) contain sufficient heat removal capability to condense the reactor system volume released during a LOCA. These conditions are consistent with the assumptions used in the accident analyses.

The minimum weight figure of 1333 pounds of ice per basket contains a 5% conservative allowance for ice loss through'sublimation. In the 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 18 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 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 provide assurance that the ice bed heat removal capacity will be retained within the specified time limits.

COOK NUCLEAR PLANT-UNIT 2 Page B 3/4 &4a

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