ML20085A166

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Proposed Tech Specs Re Secondary Containment Draw Down & Vacuum Surveillance Requirement Acceptance Criteria
ML20085A166
Person / Time
Site: Hatch  Southern Nuclear icon.png
Issue date: 06/06/1995
From:
GEORGIA POWER CO.
To:
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ML20085A157 List:
References
NUDOCS 9506140079
Download: ML20085A166 (17)
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!

SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.6.4.1.3 ------------------NOTE-------------------

The number of standby gas treatment (SGT) I subsystem (s) required for this Surveillance is dependent on the secondary containment configuration, and shall be one less than the number required to meet LC0 3.6.4.3, " Standby Gas Treatment (SGT) System," for the given configuration.

Verify required SGT subsystem (s) will 18 months on a draw down the secondary containment to STAGGERED TEST 2: 0.20 inch of vacuum water gauge in BASIS l s 120 seconds.

SR 3.6.4.1.4 ------------------NOTE-------------------

The number of SGT subsystem (s) required for this Surveillar.ce is dependent on the secondary containment configuration, and shall be one less than the number required to meet LCO 3.6.4.3, " Standby Gas Treatment (SGT) System," for the given configuration.

Verify required SGT subsystem (s) can 18 months on a maintain 2: 0.20 inch of vacuum water STAGGERED TEST l gauge in the secondary containment for BASIS 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> at a flow rate s 4000 cfm for each subsystem.

9506140079 950606 PDR ADOCK 05000321 ,

P PDR I HATCH UNIT 1 3.6-38 Proposed Change 6/2/95 l 1

l i

Secondary Containment 3.6.4.1 s

SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.6.4.1.3 ------------------NOTE-------------------

The number of standby gas treatment (SGT) subsystem (s) required for this Surveillance is dependent on the secondary containment configuration, and shall be one less than the number required to meet LCO 3.6.4.3, " Standby Gas Treatment (SGT) System," for the given configuration.

Verify required SGT subsystem (s).will 18 months on a draw down the secondary containment to STAGGERED TEST 2: 0.20 inch of vacuum water gauge in BASIS {

s; 120 seconds.

SR 3.6.4.1.4 ------------------NOTE----------- -------

The number of SGT subsystem (s) required for this Surveillance is dependent on the secondary containment configuration, and shall be one less than the number required to meet LC0 3.6.4.3, " Standby Gas Treatment (SGT) System," for the given configuration.

Verify required SGT subsystem (s) can 18 months on a  !

maintain 2: 0.20 inch of vacuum water STAGGERED TEST l gauge in the secondary containment for BASIS 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> at a flow rate s 4000 cfm for each subsystem.

HATCH UNIT 2 3.6-40 Proposed Change 6/2/95

SURVEILLANCE FREQUENCY SR 3.6.4.1.3 ------------------NOTE-------------------

The number of standby gas treatment (SGT) subsystem (s) required for this Surveillance is dependent on the secondary containment configuration, and shall be one less than the number required to meet LC0 3.6.4.3, " Standby Gas Treatment (SGT) System," for the given configuration.

Verify required SGT suosystem(s) will 18 months on a

, -- 1 , draw down the secondary containment to STAGGERED TEST O

/j.;o i N inchsof i

120vacuum seconds. water gauge in BASIS SR 3.6.4.1.4 ------------------NOTE-------------------

The number of SGT subsystem (s) required for this Surveillance is dependent on the secondary containment configuration, and shall be one less than the number required to meet LC0 3.6.4.3, " Standby Gas Treatment (SGT) System," for the given configuration.

j e

({<j, g g '. Vo ' uired SGT subsystem (s) can 18 months on a maintain a .25 inch of vacuum water STAGGERED TEST gauge in the secondary containment for BASIS 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> at a flow rate s 4000 cfm for each subsystem.

HATCH UNIT 1 3.6-38 Amendment No. 195

Secondary Containment 3.6.4.1 SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.6.4.1.3 ------------------NOTE-------------------

The number of standby gas treatment (SGT) subsystem (s) required for this Surveillance is dependent on the secondary containment configuration, and shall be one less than the number required to meet LC0 3.6.4.3, " Standby Gas Treatment (SGT) System," for the given configuration.

Verify required SGT subsystem (s) will 18 months on a d STAGGERED TEST O Ao %rawdownthesecondarycontainmentto inch of vacuum water gauge in BASIS s 120 seconds.

SR 3.6.4.1.4 ------------------NOTE-------------------

The number of SGT subsystem (s) required for this Surveillance is dependent on the secondary containment configuration, and shall be one less than the number required to meet LCO 3.6.4.3, " Standby Gas Treatment (SGT) System," for the '

given configuration.

_varifv required SGT subsystem (s) can 18 months on a O. A o mainth inch of vacuum water STAGGERED TEST gauge in the secondary containment for BASIS 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> at a flow rate s 4000 cfm for each i subsystem. '

l l

HATCH UNIT 2 3.6-40 Amendment No. 135

Enclosure 4 Edwin I. Hatch Nuclear Plant Request to Revise Technical Specifications:

Secondary Containment Draw Down Acceptance Criteria l l

BARS Channes L

0 e

4 1

i t

s I

I i

k t

HL-4861 E4-1

Secondary Containment B 3.6.4.1 BASES APPLICABLE Secondary containment satisfies Criterion 3 of the NRC SAFETY ANALYSES Policy Statement (Ref. 4).

(continued)

LC0 An OPERABLE secondary containment provides a control volume into which fission products that bypass or leak from primary containment, or are released from the reactor coolant pressure boundary components located in secondary containment, can be diluted and processed prior to release to the environment. For the secondary containment to be considered OPERABLE, it must have adequate leak tightness to ensure that the required vacuum (0.20 inch of vacuum) can be established and maintained. The secondary containment l boundary required to be OPERABLE is dependent on the operating status of both units, as well as the configuration of doors, hatches, refueling floor plugs, SCIVs, and available flow paths to SGT Systems. The required boundary encompasses the zones which can be postulated to contain fission products from accidents required to be considered for the condition of each unit, and furthermore, must include zones not isolated from the SGT subsystems being credited for meeting LCO 3.6.4.3. Allowed configurations, associated SGT subsystem requirements, and associated SCIV requirements are detailed in the Technical Requirements Manual (Ref. 3).

APPLICABILITY In MODES 1, 2, and 3, a LOCA could lead to a fission product release to primary containment that leaks to secondary containment (the reactor building zons and potentially the refueling floor zone). Therefore, secondary containment OPERABILITY is required during the same operating conditions that require primary containment OPERABILITY.

In MODES 4 and 5, the probability and consequences of the LOCA are reduced due to the pressure and temperature limitations in these MODES. Therefore, maintaining secondary containment OPERABLE is not required in MODE 4 or 5 to ensure a control volume, except for other situations for which significant releases of radioactive material can be postulated, such as during OPDRVs, during CORE ALTERATIONS, or during movement of irradiated fuel assemblies in the secondary containment. (Note, moving irradiated fuel assemblies in the secondary containment may (continued)

HATCH UNIT 1 B 3.6-76 PROPOSED CHANGE 6/2/95

~

)

l Secondary Containment l B 3.6.4.1 BASES SURVEILLANCE SR 3.6.4.1.3 and SR 3.6.4.1.4 REQUIREMENTS (continued) The Unit I and Unit 2 SGT Systems exhausts the secondary containment atmosphere to the environment through appropriate treatment equipment. To ensure that all fission products are treated, SR 3.6.4.1.3 verifies that the appropriate SGT System (s) will rapidly establish and maintain a negative pressure in the secondary containment. l This is confirmed by demonstrating that the required SGT subsystem (s) will draw down the secondary containment to 2 0.20 inch of vacuum water gauge in s 120 seconds. This l cannot be accomplished if the secondary containment boundary is not intact. SR 3.6.4.1.4 demonstrates that the required SGT subsystem (s) can maintain 2 0.20 inch of vacuum water l gauge for I hour at a flow rate s 4000 cfm for each SGT subsystem. The 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> test period allows secondary containment to be in thermal equilibrium at steady state conditions. Therefore, these two tests are used to ensure secondary containment boundary integrity. Since these SRs are secondary containment tests, they need not be performed with each SGT subsystem. The SGT subsystems are tested on a STAGGERED TEST BASIS, however, to ensure that in addition to the requirements of LCO 3.6.4.3, each SGT subsystem or combination of subsystems will perform this test. The number of SGT subsystems and the required combinations are dependent on the configuration of the secondary containment and are detailed in the Technical Requirements Manual (Ref.

3). The Note to SR 3.6.4.1.3 and SR 3.6.4.1.4 specifies that the number of required SGT subsystems be one less than the number required to meet LC0 3.6.4.3, " Standby Gas Treatment (SGT) System," for the given configuration.

Operating experience has shown these components usually pass the Surveillance when performed at the 18 month Frequency.

Therefore, the Frequency was concluded to be acceptable from a reliability standpoint.

REFERENCES 1. FSAR, Section 14.4.3.

2. FSAR, Section 14.4.4.
3. Technical Requirements Manual.
4. NRC No.93-102, " Final Policy Statement on Technical Specification Improvements," July 23, 1993.

I HATCH UNIT 1 B 3.6-79 PROPOSED CHANGE 6/2/95

,s

' SGT System B 3.6.4.3 BASES l

BACKGROUND maintained at a negative pressure when the system is in l (continued) operation, to conservatively ensure zero exfiltration of air  !

from the building when exposed to winds as high as 31 mph.

The demister is provided to remove entrained water in the air, while the electric heater reduces the relative humidity of the airstream to < 70% (Refs. 2 and 3). The prefilter removes large particulate matter, while the HEPA filter removes fine particulate matter and protects the charcoal i from fouling. The charcoal adsorbers remove gaseous '

elemental iodine and organic iodides, and the final HEPA filter collects any carbon fines exhausted from the charcoal i adsorber.

lt The Unit 1 and Unit 2 SGT Systems automatically start and i operate in response to actuation signals indicative of i conditions or an accident that could require operation of  !

the system. Following initiation, all required charcoal filter train fans start. Upon verification that the required subsystems are operating, the redundant required subsystem is normally shut down. )

l l

APPLICABLE The design basis for the Unit 1 and Unit 2 SGT Systems is to ,

SAFETY ANALYSES mitigate the consequences of a loss of coolant accident and {

fuel handling accidents (Refs. 2 and 3). For all events  :

analyzed, the SGT Systems are shown to be automatically  ;

initiated to reduce, via filtration and adsorption, the I radioactive material released to the environment. ]

The SGT System satisfies Criterion 3 of the NRC Policy Statement (Ref. 5).

LCO Following a DBA, a minimum number of SGT subsystems are f required to maintain the secondary containment at a negative '

pressure with respect to the environment and to process gaseous releases. Meeting the LC0 requirements for OPERABLE subsystems ensures operation of the minimum number of SGT subsystems in the event of a single active failure. The required number of SGT subsystems is dependent on the (continued)

HATCH UNIT 1 B 3.6-88 PROPOSED CHANGE 6/2/95

Secondary Containment B 3.6.4.1 BASES APPLICABLE Secondary containment satisfies Criterion 3 of the NRC SAFETY ANALYSIS Policy Statement (Ref. 4).

(continued)

LCO An OPERABLE secondary containment provides a control volume into which fission products that bypass or leak from primary containment, or are released from the reactor coolant pressure boundary components located in secondary containment, can be diluted and processed prior to release to the environment. For the secondary containment to be considered OPERABLE, it must have adequate leak tightness to ensure that the required vacuum (0.20 inch of vacuum) can be l established and maintained. The secondary containment boundary required to be OPERABLE is dependent on the operating status of both units, as well as the configuration of doors, hatches, refueling floor plugs, SCIVs, and available flow paths to SGT Systems. The required boundary encompasses the zones which can be postulated to contain fission products from accidents required to be considered for the condition of each unit, and furthermore, must include zones not isolated from the SGT subsystems being credited for meeting LC0 3.6.4.3. Allowed configurations, ,

associated SGT subsystem requirements, and associated SCIV l requirements are detailed in the Technical Requirements Manual (Ref. 3).

APPLICABILITY In MODES I, 2, and 3, a LOCA could lead to a fission product release to primary containment that leaks to secondary containment (the reactor building zone and potentially the refueling floor zone). Therefore, secondary containment OPERABILITY is required during the same operating conditions that require primary containment OPERABILITY.

In MODES 4 and 5, the probability and consequences cf the LOCA are reduced due to the pressure and temperature limitations in these MODES. Therefore, maintaining secondary containment OPERABLE is not required in MODE 4 or 5 to ensure a control volume, except for other situations for which significant releases of radioactive matarial can be postulated, such as during OPDRVs, during CORL ALTERATIONS, or during movement of irradiated fuel assemblies in the secondary containment. (Note, moving ,

irradiated fuel assemblies in the secondary containment may (continued)

HATCH UNIT 2 B 3.6-83 PROPOSED CHANGE 6/2/95

Secondary Containmer.t B 3.6.4.1 BASES SURVEILLANCE SR 3.6.4.1.3 and SR 3.6.4.1.4 REQUIREMENTS (continued) The Unit 1 and Unit 2 SGT Systems exhausts the secondary  ;

containment atmosphere to the environment through  !

appropriate treatment equipment. To ensure that all fission products are treated, SR 3.6.4.1.3 verifies that the appropriate SGT System (s) will rapidly establish and maintain a negative pressure in the secondary containment. l This is confirmed by demonstrating that the required SGT subsystem (s) will draw down the secondary containment to 2 0.20 inch of vacuum water gauge in s 120 seconds. This l cannot be accomplished if the secondary containment boundary is not intact. SR 3.6.4.1.4 demonstrates that the required SGT subsystem (s) can maintain 2 0.20 inch of vacuum water l gauge for 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> at a flow rate s 4000 cfm for each SGT subsystem. The 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> test period allows secondary containment to be in thermal equilibrium at steady state conditions. Therefore, these two tests are used to ensure secondary containment bour.dary integrity. Since these SRs are secondary containment tests, they need not be performed

.with each SGT subsystem. The SGT subsystems are tested on a STAGGERED TEST BASIS, however, to ensure that in addition to the requirements of LCO 3.6.4.3, each SGT subsystem or combination of subsystems will perform this test. The number of SGT subsystems and the required combinations are dependent on the configuration of the secondary containment and are detailed in the Technical Requirements Manual (Ref. 3). The Note to SR 3.6.4.1.3 and SR 3.6.4.1.4 specifies that the number of required SGT subsystems be one less than the number required to meet LC0 3.6.4.3, " Standby Gas Treatment (SGT) System," for the given configuration.

Operating experience has shown these components usually pass the Surveillance when performed at the 18 month Frequency.

Therefore, the Frequency was concluded to be acceptable from a reliability standpoint.

REFERENCES 1. FSAR, Section 15.1.39.

2. FSAR, Section 15.1.41.
3. Technical Requirements Manual.
4. NRC No. 93-iO2, " Final Policy Statement on Technical Specification Improvements," July 23, 1993.

HATCH UNIT 2 B 3.6-86 PROPOSED CHANGE 6/2/95

, SGT System B 3.6.4.3 BASES BACKGROUND maintained at a negative pressure when the system is in (continued) operation, to conservatively ensure zero exfiltration of air from the building when exposed to winds as high as 31 mph.

I The demister is provided to remove entrained water in the air, while the electric heater reduces the relative humidity of the airstream to < 70% (Refs. 2 and 3). The prefilter removes large particulate matter, while the HEPA filter {

removes fine particulate matter and protects the charcoal  !

from fouling. The charcoal adsorbers remove gaseous J elemental iodine and organic iodides, and the final HEPA filter collects any carbon fines exhausted from the charcoal adsorber.

The Unit I and 'Jnit 2 SGT Systems automatically start and I operate in response to actuation signals indicative of j conditions or an accident that could require operation of  !

the system. Following initiation, all required charcoal '

filter train fans start. Upon verification that the required subsystems are operating, the redundant required i subsystem is normally shut down. l APPLICABLE The design basis for the Unit I and Unit 2 SGT Systems is to SAFETY ANALYSES mitigate the consequences of a loss of coolant accident and fuel handling accidents (Refs. 2, 3, 4, and 5). For all events analyzed, the SGT Systems are shown to be automatically initiated to reduce, via filtration and adsorption, the radioactive material released to the -

environment.

The SGT System satisfies Criterion 3 of the NRC Policy Statement (Ref. 7).

LC0 F0' lowing a DBA, a minimum number of SGT subsystems are required to maintain the secondary containment at a negative pressure with respect to the environment and to process gaseous releases. Meeting the LC0 requirements for OPERABLE subsystems ensures operation of the minimum number of SGT subsystems in the event of a single active failure. The required number of SGT subsystems is dependent on the (cor.tinued)

HATCH UNIT 2 B 3.6-95 PROPOSED CHANGE 6/5/95 i

j

Secondary Containment B 3.6.4.1 BASES l APPLICABLE Secondary containment satisfies Criterion 3 of the NRC l SAFETY ANALYSES Policy Statement (Ref. 4).

(continued)

LCO An OPERABLE secondary containment provides a control volume '

into which fission products that bypass or leak from primary containment, or are released from the reactor coolant ,

pressure boundary components located in secondary l containment, can be diluted and processed prior to release '

to the environment. For the secondary containment to be considered OPERABLE, it must have ad uate leak tightness to ensure that the required vacuum tan be es a hed and (o.a o maintained. The secondary containment boundary required to  ;,,4 #

be OPERABLE is dependent on the operating status of both units, as well as the configuration of doors, hatches, y ""'d refueling floor plugs, SCIVs, and available flow paths to SGT Systems. The required boundary encompasses the zones which can be postulated to contain fission products from accidents required to be considered for the condition of each unit, and furthermore, must include zones not isolated i from the SGT subsystems being credited for meeting j LC0 3.6.4.3. Allowed configurations, associated SGT j

subsystem requirements, and associated SCIV requirements are i detailed in the Technical Requirements Manual (Ref. 3). {

APPLICABILITY In MODES 1, 2, and 3, a LOCA could lead to a fission product release to primary containment that leaks to secondary containment (the reactor building zone and potentially the refueling floor zone). Therefore, secondary containment OPERABILITY is required during the same operating conditions that require primary containment OPERABILITY.

In MODES 4 and 5, the probability and consequences of the LOCA are reduced due to the pressure and temperature limitations in these MODES. Therefore, maintaining secondary containment OPERABLE is not required in MODE 4 or 5 to ensure a control volume, except for other situations for which significant releases of radioactive material can be postulated, such as during OPDRVs, during CORE ALTERATIONS, or during movement of irradiated fuel assemblies in the secondary containment. (Note, moving irradiated fuel assemblies in the secondary containment may (continued)

HATCH UNIT 1 B 3.6-76 REVISION 0

Secondary Containment B 3.6.4.1 BASES SURVEILLANCE SR 3.6.4.1.3 and SR 3.6/4.1.4 REQUIREMENTS (continued) The Unit I and Unit 2 SGT Systems exhausts the secondary containment atmosphere to the environment through appropriate treatment equipment. To ensure that all fission products are treated, SR 3.6.4.1.3 verifies that the appropriate SGT System (s) will rapidly establish and f '- maintain a pressure in the secondary containment Ahaws; ney Ne less then the lwest pcstuleted prerrere external to th;-

-nand:ry cont:in::nt F=d==y. This is confirmed by demonstrating that the required SGT subsystem (s) will draw down the secondary containment to a: 9%it inch of vacuum ^ 2O water gauge in s 120 seconds. This cannot be accomplished if the secnndary containment boundary is not intact.

SR 3.6.4.1.4 demonstrates that the required SGT subsystem (s)

O RO can maintain airth inch of vacuum water gauge for I hour at a flow rate s 4000 cfm for each SGT subsystem. The I hour test period allows secondary containment to be in thermal equilibrium at steady state conditions. Therefore, these two tests are used to ensure secondary containment boundary integrity. Since these SRs are secondary containment tests, they need not be performed with each SGT subsystem. The SGT subsystems are tested on a STAGGERED TEST BASIS, however, to ensure that in addition to the requirements of LCO 3.6.4.3, each SGT subsystem or combination of subsystems will perform this test. The number of SGT subsystems and the required combinations are dependent on the configuration of the secondary containment and are detailed in the Technical Requirements Manual (Ref. 3). The Note to SR 3.6.4.1.3 and SR 3.6.4.1.4 specifies that the number of required SGT subsystems be one less than the number required to meet LCO 3.6.4.3, " Standby Gas Treatment (SGT) System," for the given configuration. Operating experience has shown these components usually pass the Surveillance when performed at the 18 month Frequency. Therefore, the Frequency was concluded to be acceptable from a reliabilit; standpoint.

REFERENCES 1. FSAR, Section 14.4.3.

2. FSAR, Section 14.4.4.
3. Technical Requirements Manual.
4. NRC No.93-102, " Final Policy Statement on Technical Specification Improvements," July 23, 1993.

HATCH UNIT 1 B 3.6-79 REVISION O

SGT System B 3.6.4.3 BASES 3 ,,. , a ,,

g BACKGROUND maintained at a negative pre sure )Nd ich:: -:: tar _ axe (continued) when the system is in operati n, wMmyNr.'m 4nterd precere required to ensure zero exfiltration of air from the building when exposed to.a_10 ;h winds as hig k <5 .

)

The demister is provided to remove entrained water in the31 mpL*

air, while the electric heater reduces the relative humidity of the airstream to < 70% (Refs. 2 and 3). The prefilter removes large particulate matter, while the HEPA filter removes fine particulate matter and protects the charcoal  !

from fouling. The charcoal adsorbers remove gaseous elemental iodine and organic iodides, and the final HEPA filter collects any carbon fines exhausted from the charcoal adsorber.

The Unit I and Unit 2 SGT Systems automatically start and operate in response to actuation signals indicative of conditions or an accident that could require operation of the system. Following initiation, all required charcoal filter train fans start. Upon verification that the required subsystems are operating, the redundant required subsystem is normally shut down.

APPLICABLE The design basis for the Unit I and Unit 2 SGT Systems is to mitigate the consequences of a loss of coolant accident and SAFETY ANALYSES fuel handling accidents (Refs. 2 and 3). For all events analyzed, the SGT Systems are shown to be automatically initiated to reduce, via filtration and adsorption, the radioactive material released to the environment.

The SGT System satisfies Criterion 3 of the NRC Policy Statement (Ref. 5). ,

l LC0 Following a DBA, a minimum number of SGT subsystems are required to maintain the secondary containment at a negative pressure with respect to the environment and to process gaseous releases. Meeting the LCO requirements for OPERABLE subsystems ensures operation of the minimum number of SGT l subsystems in the event of a single active failure. The required number of SGT subsystems is dependent on the ]

(continued)

HATCH UNIT 1 B 3.6-88 REVISION O

Secondary Containment B 3.6.4.1 BASES APPLICABLE Secondary containment satisfies Criterion 3 of the NRC 7FETY ANALYSIS Policy Statement (Ref. 4).

(continued)

LC0 An OPERABLE secondary containment provides a control volume into which fission products that bypass or leak from primary containment, or are released from the reactor coolant pressure boundary components located in secondary containment, can be diluted and processed prior to release to the environment. For the secondary containment to be Co.20 considered OPERABLE, it must have adeauate leak tightness t i% W ensure that the required facuum can be established and N w ,,,)

maintained. The secondary containment boundary required to be OPERABLE is dependent on the operating status of both units, as well as the configuration of doors, hatches, refueling floor plugs, SCIVs, and available flow paths to SGT Systems. The required boundary encompasses the zones which can be postulated to contain fission products from accidents required to be considered for the condition of each unit, and furthermore, must include zones not isolated from the SGT subsystems being credited for meeting LC0 3.6.4.3. Allowed configurations, associated SGT subsystem requirements, and associated SCIV requirements are detailed in the Technical Requirements Manual (Ref. 3).

APPLICABILITY In MODES 1, 2, and 3, a LOCA could lead to a fission product l release to primary containment that leaks to secondary containment (the reactor building zone and potentially the refueling floor zone). Therefore, secondary containment OPERABILITY is required during the same operating conditions that require primary containment OPERABILITY.

In MODES 4 and 5, the probability and consequences of the LOCA are reduced due to the pressure and temperature limitations in these MODES. Therefore, maintaining secondary containment OPERABLE is not required in MODE 4 ,

or 5 to ensure a control volume, except for other situations 1 for which significant releases of radioactive material can be postulated, such as during OPDRVs, during CORE ALTERATIONS, or during movement of irradiated fuel assemblies in the secondary containment. (Note, moving irradic.ted fuel assemblies in the secondary containment may (continued)

HATCH UNIT 2 B 3.6-83 REVISION 0

Secondary Containment B 3.6.4.1 BASES SURVEILLANCE SR 3.6.4.1.3 and SR 3.6.4.1.4 REQUIREMENTS (continued) The Unit I and Unit 2 SGT Systems exhausts the secondary containment atmosphere to the environment through appropriate treatment equipment. To ensure that all fission products are treated, SR 3.6.4.1.3 verifies that the 4 appropriate SGT System (s) will rapidly establish and T"m aintain a pressure in the secondary containment.th;t i:

less-than4hc icwest postulated presswe edin nal iv -the secondacy-contHnment beundary. This is confirmed by demonstrating that the required SGT subsystem (s) will draw down the secondary containment to a OhtS~1nch or vacuum MO water gauge in s 120 seconds. This cannot be accomplished if the secondary containment boundary is not intact.

SR 3.6.4.1.4 demonstrates that the required SGT subsystem (s)

O AO -cairmaintain 2 OriMi inch of vacuum water gauge for I hour at a flow rate s 4000 cfm for each SGT subsystem. The I hour test period allows secondary containment to be in thermal equilibrium at steady state conditions. Therefore, these two tests are used to ensure secondary containment boundary integrity. Since these SRs are secondary containment tests, they need not be performed with each SGT subsystem. The SGT subsystems are tested on a STAGGERED TEST BASIS, however, to ensure that in addition to the requirements of LCO 3.6.4.3, each SGT subsystem or combination of subsystems will perform this test. Tne number of SGT subsystems and the required combinations are dependent on the configuration of the secondary containment and are detailed in the Technical Requirements Manual (Ref. 3). The Note to SR 3.6.4.1.3 and SR 3.6.4.1.4 specifies that the number of required SGT subsystems be one less than the number required to meet LC0 3.6.4.3, " Standby Gas Treatment (SGT) System," for the given configuration. Operating experience has shown these components usually pass the Surveillance when performed at the 18 month Frequency. Therefore, the Frequency was concluded to be acceptable from a reliability standpoint.

REFERENCES 1. FSAR, Section 15.1.39.

2. FSAR, Section 15.1.41.
3. Technical Requirements Manual.
4. NRC No.93-102, " Final Policy Statement on Technical Specification Improvements," July 23, 1993.

HATCH UNIT 2 B 3.6-86 REVISION O

1 SGT System 1 B 3.6.4.3 l l

BASES 1

ConP rva+;<,

BACKGROUND maintained at a negative pressure of at:r g, (continued) ;h h::thc h te n.. sure when the system is in operation, d 'G _3 rxxt: r

.. ..__ ,. - _ ..,_.... __ -_._ zero exfiltration of air from the building when exposed (e : "' ," winds 95 hi 3h 55 31 mph The demister is provided to remove entrained water in the '

air, while the electric heater reduces the relative humidity of the airstream to < 70% (Refs. 2 and 3). The prefilter removes large particulate matter, while the HEPA filter removes fine particulate matter and protects the charcoal from fouling. The charcoal adsorbers remove gaseous elemental iodine and organic iodides, and the final HEPA filter collects any carbon fines exhausted from the charcoal adsorber.

The Unit 1 and Unit 2 SGT Systems automatically start and operate in response to actuation signals indicative of conditions or an accident that could require operation of the system. Following initiation, all required charcoal filter train fans start. Upon verification that the required subsystems are operating, the redundant required subsystem is normally shut down.

APPLICABLE The design basis for the Unit I and Unit 2 SGT Systems is to SAFETY ANALYSES mitigate the consequences of a loss of coolant accident and fuel handling accidents (Refs. 2, 3, 4, and 5). For all events analyzed, the SGT Systems are shown to be automatically initiated to reduce, via filtration and adsorption, the radioactive material released to the '

environment.

The SGT System satisfies criterion 3 of the NRC Policy Statement (Ref. 7).

LC0 Following a DBA, a minimum number of SGT subsystems are required to maintain the secondary containment at a negative pressure with respect to the environment and to process gaseous releases. Meeting the LCO requirements for OPERABLE subsystems ensures operation of the minimum number of SGT subsystems in the event of a single active failure. The required number of SGT subsystems is dependent on the i (continued)

HATCH UNIT 2 B 3.6-95 REVISION 0

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