ML20045E728

Proposed TS 3.7.A.4 & 3.6.4.1 for Units 1 & 2,respectively, Allowing One or More Suppression chamber-drywell Vacuum Breakers to Open During Surveillance Testing

ML20045E728
Person / Time
Site:	Hatch
Issue date:	06/28/1993
From:	GEORGIA POWER CO.
To:
Shared Package
ML20045E721	List: ML20045E720 ML20045E726 ML20045E728
References
NUDOCS 9307020362
Download: ML20045E728 (10)

Text

_ . - _ _ .

Enclosure 3 Edwin I. Hatch Nuclear Plant Request to Revise Technical Specifications Suppression Chamber - Drywell Vacuum Breakers Pace Chanae Instructions The proposed change to the Plant Hatch Unit 1 Technical Specifications will be incorporated as follows:

Remove Pace Insert Paae 3.7-8 3.7-8 3.7-31 3.7-31 The proposed change to the Plant Hatch Unit 2 Technical Specifications will be incorporated as follows:

Remove Pace Insert Paae 3/4 6-33 3/4 6-33 B 3/4 6-5 8 3/4 6-5 t

l l

l l

HL-3359 005705 E3-1 9307020362 930628 i PDR ADOCK 05000321 P PDR

LIMITING CONDITIONS FOR OPERATION SURVEILLANCE REQUIREMENTS 3.7.A.4. Pressure Suppression Chamber to Drs* qd1 ,

4.7. A.4. Pressure Suppression Chamber to '

Vacuum ~ Breakers Drywell vacuum Breakers

a. When primary containment is required, a. The pressure suppression all pressure suppression chamber to chamber drywell vacuum drywell vacuum breakers shall be breakers shall be visually

- noerableandposjtionedinthefully inspected each refueling

ed position-teneept-dsring te.i'uw) outage and checked for )

oco /t that up to three vacuum breakers operability monthly.

ray increrable for opening provided

.at '. ey L'e known to be in the

..ased " .cson.

b. If se t the closed position

b. Closed position is indicated 1 indica .,", )O ts for a pressure by redundant lights in the suppressire ; .mber to iirywell vacuum main control room which are breaker is inoperable, continued operated by two separate reactor operation is permi sible closed position switches and only if: (1) the operabilivy of circuits for each vacuum the redundant closed position breaker. If either indicating circuit is verified, redundant position indicating and (2) a leakage test of the light is inoperable or shows pressure suppression chamber to that the vacuum breaker is drywell vacuum breaker system is stuck open, the affected satisfactorily performed within 24 vacuum breaker shall be hours. exercised within two hours to demonstrate operability of If eithsr of these requirements the remaining position ca",not be met, the reactor must indicating circuit, and every I

?se in the cold shutdown condition 15 days thereaf ter_ until within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. the redundant circuit is repaired.

c. The differential pressure which actuates c. Each pressure suppression the pressure suppression chamber to dry- chamber to drywell vacuum well vacuum breakers shall be 0.5 psid breaker shall be' tested or less. for proper opening dif feren-tial pressure each refueling

d. The total leakage between the drywell outage.

and pressure suppression chamber shall be less than the equivalent leakage d. A leak test of the pressure through a one-inch diameter orifice suppression chamber to at a differential pressure of one psi. drywell vacuum breaker ,

system shall be conducted K ca't y in:L ,M rcua? R g J n l$ g W' at the nd of each refueMng outage and every 15 days

& J GJ .& Tm/6 Sa'64//d 4 {e % when reactor operation is C# M//fr) /%gM&;&M; 77,.'6f. continued under the require-sents of 3.7.A.4.b.

% W.Mc/)ti yinfq). }

I HATCH - UNIT 1 3.7-8 Amendment No. 29

t BASES FOR LIMITING CONDITIONS FOR OPERATION 3.7.A.4. Pressure Suooression Chamber to Drywell Vacuum Breakers .

The purpose of the pressure suppression chamber to drywell vacuum, breakers is to equalize pressure in order to maintain structural integrity of the containment. <- _

gg,77 ffgg The twelve pressure suppression chamber to drywell vacuum breakers limit the pressure differential between the suppression chamber and 45FN6d +

drywell during post-accident drywell cooling operations. They are sized on the basis of the Bodega Bay pressure suppression system tests. The ASME Boiler and Pressure Vessel Code,Section III, Subsection B, allows a 2 psig vacuum for the drywell. With three vacuum relief valves secured in the closed position and nine operable valves, containment integrity is not impaired.

The Bodega Bay pressure suppression tests provided the most limiting requirements for sizing these vacuum breakers; a minimum vacuum breaker flow area equal to 1/16 the downcomer vent area was established by the test to minimize the water oscil'ations in the downcomer. The downcomer vent area for Hatch is approxinately-214 ft8 which results in a minimum total vacuum breater area of 13.4 ft* and translates into nine 1B-inch vacuum breakers.

The 12 vacuum breakers actually provide more than the minimum re-quired area even conLidering the single failure of one vacuum breaker. Suppression chamber to drywell differential pressure resulting from vacuum breaker sizing of 1/16 the downcomer vent area is well below the design requirement of approximately 2 psid.-

Reference Section 5.2.3.6.1 of the FSAR.

The position indication system for the Hatch pressure suppression chamber to drywell vacuum breakers consists of three position switches, two of which are highly sensitive closed position indicating switches which are physically separated from each other. Due to the

" snap" action of the magnetic latch provided, the "not closed" position would be indicated immediately upon opening. The closed position switches will indicate the valve to b& open when the pallet is approximately .015 to .035 inches away from the seat at the location of the switches; the pallet would be at an angle of approximately 3 to 7 minutes open, respectively, at that time.

Reference Section 5.2.3.6.1 of the FSAR.

l HAICH - UNIT 1 3.7-21

Differential pressure between the suppression chamber and the drywell can be due l to depressurization of the drywell caused by events such as cooling cycles, ,. ;

inadvertent drywell spray actuation, and steam condensation from sprays or ,

subcooled water reflood of a break in the event of a primary system rupture.

Operations which add gas to the suppression chamber and/or remove-gas from the drywell can also increase the differential pressure. For example, such '

operations may include inerting or deinerting of the primary containment.  !

6 k)SLf7~s l

v P

t E

[

f r

o i

f

-l t

1 i

J I

i e - r,, ye, ,,p. n y ,

CONTAINMENT SYSTEMS 3/4.6.4 VACUUM RELIEF . .

SUPPRESS:0N CHAMBER - DRYWELL VACUUM BREAKERS t-

'LIMITINGCONDITIONF5'ROPERATION 3.6.4.1 All su'ppression chamber - drywell vacuum breakers shall be OPERABLE and closed *with: l .

a. A total leakage between the suppression chamber and the drywell or less than the equivalent leakage through a 1 inch diameter orifice at a differential pressure of 1 psi,

b. The redundant position indicators OPERABLE, and

c. An opening set point of s 0.5 psid.

APPLICABILITY: CONDITIONS 1, 2 and 3.

ACTION: ,

a. With up to two suppression chamber - drywell vacuum breakers inoperable for opening but known to be closed, the provisions of Specification 3.0.4 are not applicable and operation may continue provided Surveillance Requirement 4.6.4.1.a is l performed on the OPERABLE vacuum breakers within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> and at least once per 15 days thereafter. Otherwise, be in at least HOT SHUTDOWN within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and in COLD SHUTDOWN within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

b. With three suppression chamber - drywell vacuum breakers inoperable for opening but known to be closed, operation may continue provided Surveillance Requirement 4.6.4.1.a is performed on the OPERABLE vacuum breaker. ithin 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> and

, at least once per 15 days thereafter. Otherwise, be in at least HOT SHUTDOWN within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and in COLD SHUTDOWN within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

c. With four suppression chamber - drywell vacuum breakers inoperable for opening but known to be closed, restore at least one inoperable vacuum breaker to OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to be in at least HOT SHUTDOWN within the next 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> s and in COLD SHUTDOWN within the fo11owing 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

f cut ca si'edL Ykuairt BEE,ftq4'y gfy ,36 CPtr) OMhd6 5uKL//t AsL5 c,ll nW.gi.i /2%vmi c:, 7?/6/Q NJ/2d08 fW/X ThQ l

l HATCH - UNIT 2 3/4 6-33 Amendment No. 13 1 l

l

A '~

. . , , , s ww. ...~-...s.: ,-

J 4

'ONTAINMENT SYSTEMS C

l BASES

(  ! 3/4.6.4 VACUbM RELIEF

~ Vacuum relief breakers are provided to equalize the pressure between the suppression chamber and drywell and between the reactor building and suppression chamber. This system will maintain the structural integrity of the primary containment under conditions of large differential pressures.

( /

.HT The vacuum breakers between the suppression chamber and the drywell must

' /MM. not be inoperable in the open position since this would allow bypassing of

. /tM1 the suppression pool in case of an accident. There are an adequate number dMT of valves to provide some redundance so that operation may continue with

[466: no more than three vacuum breakers inoperable in the closed position.

Each set of vacuum breakers between the reactor building and the suppression chamber provides 100% relief, so operation may continue with one valve out-of-service for 7 days.

3/4.6.5 SECONDARY CONTAINMENT .

( '

Secondary containment is designed to minimize any ground level release of radioactive material which may result frbm an accident. The reactor building provides secondary containment during normal operation when the drywell is sealed and in service. When the reactor is shutdown or during refueling the drywell may be open and the reactor building then becomes the primary containment.

Establishingandmaintainingavacuuminth$buildingwiththestandby gas treatment system once per 18 months, along with the surveillance of the doors, hatches and dampers, is adequate to ensure that there are no violations of the integrity of the secondary containment. Only one closed damper in each penetration line is required to maintain the integrity of the secondary containment.

3/4.6.6 CONTAINMENT ATMOSPHERE CONTROL 1 The OPERABILITY of the containment iodinc filter trains ensures that sufficient iodine removal capability will be available in the event of a

( LOCA. The reduction in containment iodine inventory reduces the resulting site boundary radiation doses associated with containment leakage. The operation of this system and resultant iodine removal capacity are consist-ent with the assumptions used in the LOCA analyses. .

(

HATCH - UNIT 2 B 3/4 6-5

e Differential pressure between the suppression chamber and the drywell can be.due .,

to depressurization of the.drywell caused by events such as cooling cycles, inadvertent drywell spray actuation, and steam condensation.from' sprays .or  ;

subcooled water reflood of a- break in the event of a primary system rupture. ,

Operations which add gas to the suppression chamber and/or remove gas from the drywell can also increase the differential pressure. For example, such operations may include functional . testing of the primary containment hydrogen recombiners and inerting/deinerting of the primary containment-.  ;

hbbL?V r

?

i i

t

?

i 4 s J

r

(

I I

l

" . t LIMITING CONDil10NS FOR OPERAl!0N SURVEILLANCE RE0VIREMENTS l 3.7.A.4 .Prgssure Sucoression Chanter to Drvwell. 4.7.A.4. Pressure Suceression Chamber tg yjtcum Breakers Drywell vacuum Breakers

a. When primary contairrent is required, a. The pressure suppression all pressure suppression chamber to chamber dryvell vacuum drywell vacum breakers shall be breakers shall be visually operable and positioned in tne fully inspected each refueling closed position

• except that up l outage and checked for to three vacu m breakers may be operability monthly.

inoperable for opening provided that they are known to be in the closed position.

b. If either of the closed position b. Closed position is indicated .

Indicating lights for a pressure by redundant lights in the. .

suppression chamber to drpell vacuum main control room which are -'

breaker is inoperable, continued operated by two separate reactor operation is p6.missible closed position switches and only if: (1) the operability of circuits for each vacuum ,

the redundant closed position breaker. If either '

indicating circuit is verified, redundant position indicating and (2) a leakage test of the light is inoperable or shows pressure suppression chamber to that the vacuum breaker is drywell vacuum breaker system is stuck open, the affected i satisfactorily perfomed within 24 vacuum breaker shall be hours. exercised within two hours to demonstrate operability of >

If either of these requirements the remaining position cannot be met, the reactor must indicating circuit, and every be in the cold shutdown condition 15 days thereafter until within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. the redundant circuit is i repaired,

c. The differential pressu m d ich actuates c. Each pressure suppression the pressure suppression charter to dry- chamber to drywell vacuum well vacum breakers shall be 0.5 psid breaker shall be tested or less, for proper opening differen-tial pressure each refueling

d. The total leakage tetween the drywell outage.

and pressure suppression charter shall ,

be less than the equivalent leakage d. A leak test of the pressure i through a one-inch diameter orifice suppression chamber to at a differential pressure of one psi. drywell vacuum breaker system shall be conducted at the end of each refueling outage and every 15 days when reactor operation is continued under the require-ments of 3.7 A.4.b.

t

• 0ne or more vacuum breakers may be open during surveillances or when performing their intended function.

HATCH - UNIT 1 3.7-8 techsp\hT93-08UI. pro /29

i

~. .

l j

. BASES FOR LIMITING CONDITIONS FOR OPERATION 3.7.A.4. pressure Sucoression Chamber to Drvwell Vacuum Breakers The purpose of the pressure suppression chamber to drywell vacuum i breakers is to equalize pressure in order to maintain structural integrity of the containment. Differential pressure between the suppression chamber and the drywell can be due to depressurization of 'i the drywell caused by events such as cooling cycles, inadvertent drywell spray actuation, and steam condensation from sprays or subcooled water reflood of a break in the event of a primary system .

rupture. . Operations which add gas to the suppression chamber and/or remove gas from the drywell can also increase the differential pressure. For example, such operations may include inerting or deinerting of the primary containment.

The twelve pressure suppression chamber to drywell vacuum breakers limit the pressure differential between the suppression chamber and ,

drywell during post-accident drywell cooling operations. They are i sized on the basis of the Bodega Bay pressure suppression system-tests. The ASME Boiler and Pressure Vessel Code,Section III, Subsection B, allows a 2 psig vacuum for the drywell. With three vacuum relief valves secured in the closed position and nine operable valves, containment integrity is not impaired.

The Bodega Bay pressure suppression tests provided the most limiting.

requirements for sizing these vacuum breakers; a minimum vacuum breaker flow area equal to 1/16 the downcomer vent area was established by the test to minimize the water oscillations in the downcomer. The downcomer vent area for Hatch is approximately 214 ft" which results in a minimum total vacuum breaker area of 13.4 ft' and translates into nine 18-inch vacuum breakers.

The 12 vacuum breakers actually provide more than the minimum re-quired area even considering the single failure of one vacuum breaker. Suppression chamber to drywell differential pressure resulting from vacuum breaker sizing of 1/16 the downtomer vent-area is well below the design requirement of approximately 2 psid.

Reference Section 5.2.3.6.1 of the FSAR.

The position indication system for the Hatch pressure suppression chamber to drywell vacuum breakers consists of three position switches, two of which are highly sensitive closed position indicating switches which are physically separated from each other. Due to the-

" snap" action of the magnetic latch provided, the "not closed" position would be indicated immediately upon opening. The closed position switches will indicate the valve to be open when the pallet is approximately .015 to .035 inches away from the seat at the location of the switches; the pallet would be at an angle of approximately 3 to 7 minutes open, respectively, at that time, ,

Reference Section 5.2.3.6.1 of the FSAR.

i 4

HATCH - UNIT 1 3.7-31 techsp\h\93-08UI. pro /0  ;

I

, t CONTAINMENT SYSTEMS [

3/4.6.4 VACUUM RELIEF SUPPRESSION CHAMBER - DRYWELL VACUUM BREAKERS LIMITING CONDITION FOR OPERATION l 3.6.4.1 All suppression chamber - drywell vacuum breakers .shall be OPERABLE and closed

• with: l

a. A total leakage between the suppression chamber and the drywel1 or less than the equivalent leakage through a 1 inch diameter orifice at a differential pressure of 1 psi, 7

b. The redundant position indicators OPERABLE, and

c. An opening set point of s 0.5 psid. '

APPLICABILI',Y: CONDITIONS 1, 2 and 3.

ACTION:

a. With up to two suppression chamber - drywell vacuum breakers T inoperable for opening but known to be closed, the provisions of Specification 3.0.4 are not applicable and operation may continue provided Surveillance Requirement 4.6.4.1.a is performed on the OPERABLE vacuum breakers within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> and at least once per 15 days thereafter. Otherwise, be in at least HOT SHUTDOWN within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and in COLD SHUTDOWN within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

b. With three suppression chamber - drywell vacuum breakers inoperable for opening but known to be closed, operation may continue provided Surveillance Requirement 4.6.4.1.a is performed on the OPERABLE vacuum breakers within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> and at least once per 15 days thereafter. Otherwise, be in at least HOT SHUTDOWN within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and in COLD SHUTDOWN within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

c. With four suppression chamber - drywell vacuum breakers inoperable for opening but known to be closed, restore'at least one inoperable vacuum breaker to OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to be in at least H0T SHUTDOWN within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and in COLD SHUTDOWN within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

• 0ne or more vacuum breakers may be open during surveillances or when performing  !

their intended function. l HATCH'- UNIT 2 3/4 6-33 techsp\h\93-08AU2. pro /13

i CONTAINMENT SYSTEMS EASES 3/4.6.4 VAC'JUM RELIEF  :

Vacuum relief breakers are provided to equalize the pressure between i the suppression chamber and drywell and between the reactor building and-suppression chamber. This system will maintain the structural integrity '

of the primary containment under conditions of large differential pressures.

Differential pressure between the suppression chamber and the drywell can be due to depressurization of the drywell caused by events such as cooling cycles, inadvertent drywell spray actuation, and steam condensation from sprays or subcooled water reflood of a break in the event of a primary system ,

rupture. Operations which add gas to the suppression chamber and/or remove 4 gas from the drywell can also increase the differential pressure. For  ;

example, such operations may include functional testing of the primary containment hydrogen recombiners and inerting/deinerting of the primary containment. '

The vacuum breakers between the suppression chamber and the drywell must not be inoperable in the open position since this would allow bypassing of the suppression pool in case of an accident. There are an adequate number of valves to provide some redundance so that operation may continue with no more than three vacuum breakers inoperable in the closed position.

Each set of vacuum breakers between the reactor building and the suppression chamber provides 100% relief, so operation may continue with one valve out-of-service for 7 days.

3/4.6.5 SECONDARY CONTAINMENT 4 Secondary containment is designed to minimize any ground level release  ;

of radioactive material which may result from an accident. The reactor building provides secondary containment during normal operation when the drywell is sealed and in service. When the reactor is shutdown or during I refueling the drywell may be open and the reactor building then becomes j the primary containment. j Establishing and maintaining a vacuum in the building with the standby gas treatment system once per 18 months, along with the surveillance of the doors, hatches and dampers, is adequate to ensure that there are no violations of the integrity of the secondary containment. Only one closed damper in each penetration line is required to maintain the integrity of I the secondary containment.

3/4.6.6 CONTAINMENT ATMOSPHERE CONTROL The OPERABILITY of the containment iodine filter trains ensures that sufficient iodine removal capability will be available in the event of a LOCA. The reduction in containment iodine inventory reduces the resulting site boundary radiation doses associated with containment leakage. 'The operation of this system and resultant iodine removal capacity are consis-tent with the assumptions used in the LOCA analyses.

HATCH - UNIT 2 B 3/4 6-5 techsp\h\93-08BU2. pro /0