Text

Proposed Tech Specs Re Containment Vacuum Relief Sys
	ML20070Q921
Person / Time
Site:	Sequoyah
Issue date:	05/16/1994
From:	; TENNESSEE VALLEY AUTHORITY
To:	;
Shared Package
ML20070Q919	List: ML20070Q916; ML20070Q921;
References
	NUDOCS 9405190254
	Download: ML20070Q921 (29)
	v • d • e

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ENCLOSURE 1 1

FROPOSED TECIINICAL SPECIFICATION CIIANGE l

SEQUOYAll NUCLEAR PLANT UNITS 1 AND 2 2

DOCKET NOS. 50-327 AND 50-328 1

(IVA-SQN-TS-93-04, REVISION 1)

LIST OF AFFECTED PAGES Unit _1-

, VIII

XIII 3/4 6-18 3/4 6-23 3/4 6-38

. 3/4 6-39 (new page)

B 3/4 6-6

_ Unit _2 VIII XIII 3/4 6-18 3/4 6-23 3/4 6-39 :

3/4 6-40 B 3/4 6-6 l

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9405190254 940516 PDR P

ADOCK 05000327 i PDR

INDEX LIMITING CONDITIONS FOR OPERATION AND SURVEILLANCE REQUIREMENTS I SECTION PAGE 3/4.6.3 CONTAINMENT ISOLATION VALVES.. . . . .... ... ..... 3/4 6-17 3/4.6.4 COMBUSTIBLE GAS CONTROL l

Hydrogen Analyzers ... . .., , .'! .... ... 3/4 6-24 l Electric Hydrogen Recombiners.. . .. . . . .. . . . ... 3/4 6-25 3/4.6.5 ICE CONDENSER ,

Ice Bed.. .... . . .. ... ..... ... . . . . . 3/4 6-26 Ice Bed Temperature Monitoring System. ... . ...... . 3/4 6-28 Ice Condenser Doors. . . .. ..... .. . . 3/4 6-29 Inlet Door Position Monitoring System.. . . .. . ... 3/4 6-31 Divider Barrier Personnel Access Doors and Equipment Hatches. .. .

..... ... .. . ...... . ... 3/4 6-32 Containment Air Return Fans... .. . . .. ... . ..... . 3/4 6-33 ,. ,

v Floor Drains. . . .. .... .. ..... . . .. 3/4 6-34 I

Refueling Canal Drains. , ....... . . ... ... ... 3/4 6-35 Divider Barrier Seal.. ..m. ..... . ...... . ... . 3/4 6-36 5ysTE 3/4.6.6 VACUUM RELIEF NAtNES/(hQ . .. . .. . .. . .. . 3/4 6-38 3/4.7 PLANT SYSTEMS 3/4.7.1 TURBINE CYCLE Safety Valves. , . . . ... . ... . ....... . 3/4 7-1 Auxiliary Feedwater System. . . . . . .. ........ 3/4 7-5 Condensate Storage Tank. . .... . .. . . ........ .. 3/4 7-7 Activity.. ... . .. .. .. . .. .. . ... 3/4 7-8 Main Steam Line Isolation Valves. ... . . .. .. .... 3/4 7-10 3/4,7.2 STEAM GENERATOR PRESSURE /TEMPdRATURE LIMITATION.. .. . 3/4 7-11 3/4.7.3 COMPONENT COOLING WATER SYSTiM. . . . ... . . 3/4 7'12 3/4.7.4 ESSENTIAL RAW COOLING WATER SYSTEM Essential Raw Cooling Water System. . .. . ... 3/4 7-13

' R 12L.

SEQUOYAH - UNIT 1 VIII Amendment No.116 June l, 1989-

._ - ~ . . - .

INDEX s

BASES

)

SECTION PAGE 3/4.4.6 REACTOR COOLANT SYSTEM LEAKAGE................. ........... B 3/4 4-4 3/4.4.7 CHEMISTRY.................................. ............... B 3/4 4-5 3/4.4.8 SPECIFIC ACTIVITY................. ...... ................. B 3/4 4-5 i i

3/4.4.9 PRESSURE / TEMPERATURE LIMITS................................ B 3/4 4-6 l 3/4.4.10 STRUCTURAL INTEGRITY...................................... B 3/4 4-14 3/4.4.11 REACTOR COOLANT SYSTEM HEAD VENTS..................... ... B 3/4 4-14 .

R161!

3/4.4.12 OVERPRESSURE PROTECTION SYSTEMS........................... B 3/4 4-14 3/4.5 EMERGENCY CORE COOLING SYSTEMS 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............................... B 3/4 5-2 3/4.6 CONTAINMENT SYSTEMS 3/4.6.1 PRIMARY CONTAINMENT.. . ................................... B 3/4 6-1 3/4.6.2 OEPRESSURIZATION 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 CONTR0L.................................... B 3/4 6-3 3/4.6,5 ICE CON 0ENSER..........., cz.............................. B 3/4 6-4 3/4.6.6 VACUUM RELIEF 4AtVE$..... b.................................. k B 3/4 6 3/4.7 PLANT SYSTEMS 3/4.7.1 TURBINE CYCLE..... ........................................ B 3/4 7-1 3/4.7.2 STEAM GENERATOR PRESSURE /TEMERATURE LIMITATION............. B 3/4 7-3 3/4.7.3 COMPONENT COOLING WATER SYSTEM......................... ... B 3/4 7-3 SEQUOYAH - UNIT 1 XIII Amendment No-.157 March 30, 1992

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. - _ . . - _ . _ . . - _ . _ _ _ _ _ ~ ---_ _ . . _ _ _ .

CONTAINMENT SYSTEMS i

l SURVEILLANCE REQUIREMENTS (Continued) l 4.6.3.2 Each isolation valve specified in Table 3.6-2 shall be demonstrated OPERABLE during the COLD SHUIDOWN or REFUELING MODE at least once per 18 months R16 by:

a. Verifying that on a Phase A containment isolation test signal, each Phase A isolation ~' valve actuates to its isolation position, i

b. Verifying that on a Phase B containment isolation test signal, each Phase B isolation valve actuates to its isolation position.

c. Verifying that on a Containment Ventilation isolation test signal, each Containment Ventilation Isolation valve a_ctuates to its isolation position' 3 P r d is 4

d. brifying4 hat-en-a-Mpt-eent-ainment-peessure-4Aoladon test sipa_1, R85

--eech-Eontainment4acuum-Re1-4ef-Vahe-ac4uates te its-isolation

. tmeion--

t

e. Verifying that on a Safety Injection test signal that the Normal R105 Charging Isolation valve actuates to its isolation position.

4.6.3.3 The isolation time of each power operated or automatic valve of .

, Table 3.6-2 shall be determined to be within its limit when tested pursuant to

Specification 4.0.5. -

1 R124 4

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O9 SEQUDYAH - UNIT 1 3/4 6-18 Amendment No. 12, 81, 101, 120

July 5. 1989

,-.$ve.-,. ... . . .- .., . . , . , - -

T TABLE 3.6 Continued) g .

v. CONTAINMFNT ISOLATION VALVES

.E 8 VALVE NUMBER FUNCTION MAXIMUM ISOLATION TIME (Fr onAsl 4

C. PHASE "A" CONTAINMENT VENT ISOLATION (Cont.)

f E 13. FCV-30-50 Upper Compt Purge Air Exh 4*

p 14. FCV-30-51 Uppe. Compt Purge Air Exh 4*

R 744

- 15. FCV-30-52 Upper Compt Purge Air Exh 4*

16. FCV-30-53 Upper Compt Purge Air Exh 4*

17. FCV-30-56 Lower Compi. Purge Air Exh 4*

18. FCV-30-57 Lower Compt Purge Air Exh 4*

19. FCV-30-58 Inst Room Purge Air Exh 4*

20. FCV-30-59 Inst Room Purge Air Exh 4*

21. FCV-90-107 Cntmt Bldg LWR Compt Air Mon 5*

22. FCV-90-108 Cntmt Bldg LWR Compt Air Mon 5*

. 23. FCV-90-109 Cntmt Bldg LWR Compt Air Mon 5*

24. FCV-90-110 Cntmt Bldg LWR Compt Air Mon 5*

w 25. FCV-90-Ill Cntmt Bldg LWR Compt Air Mon 5*

1 26. FCV-90-113 Cntmt Bldg UPR Compt Air Mon 5*

cn 27. FCV-90-Il4 Cntmt Bldg UPR Compt Air Mon 5*

A

!8. FCV-90-115 Cntmt Bldg UPR Compt Air Mon 5*

29. FCV-90-116 Cntmt Bldg UPR Compt Air Mon 5*

30. FCV-90-117 Cntmt Bldg UPR Compt Air Mon 5*

D. OTHER gy k 1. FGV40-46 Vacm-ReMef-Isolat4on-Valve Vacuum Rel4ef Isolat4cn-Valve 25 g m.; 2. F4V40-47 2 F>-

Ex 3. FCV-30-48 Vacuum Relief Isohtien Valve 2b R105

=g FCV-62-90 Normal Charging Isolation Valve 12 p-55"

Provisions of LC0 3.u.4 are not applicable if valve is secured in its isolated position with power removed Riac 5 and leakage limits of Specification 4.6.1.1.c are satisfied. For purge valves, leakage limits under Surveillance Requirement 4.6.1.9.3 must j also be satisfied.

ro

Provisions of LCO 3.0.4 are not applir. ble if valve is secured . !ts isolated position with power removed R41 y

and either FCV-62-73 or FCV-62-74 is maintained operable. j-

- This valve is required after completion of the associated modification. R86

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C'ONTAINMENT SYSTEMS

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3/4.'6.6 VACUUM RELIEF VALV_ES E ,/ l

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LIMITING' CONDITION FOR OPERATION /

3.6.6.1 The primary containment vacuum relief valves OPERABLE with shall oe/

an actuation set point of less than or equal to 0.1 PSID. / .

s / l APPLICABILITY: MODES 1, 2, 3 and 4.

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ACTION:

N With one primary containment vacuum relief valve inoperable, restore the valve to OPERABLE status within 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months or be in at least' HOT STANDBY within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in COLD stiUTDOWN within the fol)6 wing 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months .

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SURVEILLANCE REQUIREMENTS \ /'

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4.6.6.1 No additional Surveillance.Re'quirements other than those required by .

Specification 4.0.5. \

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SEQUOYAH - UNIT 1 3/4 6-38 i N

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i CONTA[HMENT SYSTEMS l 3/4.6.6 VACUUM RELIEF SYSTEM LIMITING CONDITION FOR OPERATION 3.6.6 Each primary containment vacuum relief line shall be OPERABLE.

APPLICABILITY: MODES 1, 2, 3, 4.

ACTION:

a. With one or more lines with one valve incapable of performing its containment isolation function, restore the valve in the af fected line (s) to OPERABLE status wit hin 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months .

b. With one or more lines with both valves incapable of performing their containment isolation function, restore at least one valve in the af fected line (s) to OPERABLE status within 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months .

c. With one line incapable of performing its vacuum relief function, restore the inoperable line to OPERABLE status within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months .

d. With two or more lines incapable of performing a vacuum relief function, restore the inoperable lines to OPERABLE status within 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months or be in at least HOT

STANDBY withing the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in' COLD SHUTDOWN within the following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months .

J SEQUOYAH - UNIT 1 3/4 6-38 l

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CONTAINMENT SYSTEMS i

SURVEILLANCE REOUIREMENTS 4.6.6 In addition to the requirements of Specification 4.0.5, demonstrate OPERABILITY at least once per 18 months by:

a. Verifying that on a high containment pressure isolation test signal, each containment. vacuum relief isolation valve actuates to its isolation position, and,

b. Verifying the opening setpoint of each vacuum relief valve is less than or equal to 0.1 psid. ,

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4 SEQUOYAH - UNIT 1 3/4 6-39 l

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, . . ~ . . . - - -.

CONTAINMENT SYSTEMS BASES T 3/4.6.5.7 and 3/4.6.5.8 FLOOR AND REFUELING CANAL DRAINS The OPERABILITY of the ice condenser floor and refueling canal drains ensures that following a LOCA, the water from the melted ice and containment spray system has access for drainage back to the containment lower compartment i

and subsequently to the sump. This condition ensures the availability of the water for long term cooling of the reactor during the post accident phase.

3/4.6.5.9 DIVIDER BARRIER SEAL The requirement for the divider barrier seal to be OPERABLE ensures that a minimum bypass steam flow will occur from the lower to the upper containment compartments during a LOCA. This condition ensures a diversion of steam i

.through the ice condenser bays that is consistent with the LOCA analyses.

3/4.6.6 VACUUM RELIEF NALSEI - v$Y5fEh

! Qhe OPERABILITY of the primary containment -to-etmosphere- vacuum I

relief va kes ensures that the containment internal pressure does not become more negative than 0.1 psid. This condition is necessary to prevent exceeding the containment design limit for internal vacuum of 0.5 psid. A l,ne consisf s of a.

vac uo en rehef *Sel*$ ion valv e , a vacoum rel,a F valve _, p;f&3, ancl a ssoc',n%d instrurneh+;en and con +ro\ c.

Tke vacuum re. l.e f ico ld.cn l <a f ue s E;lopen an d a re ches.yned Gr angl e G fore h en sum L+ d lea s+ ke I,nes are_

avalable. Gr ee n+a nmed vacuum re la f. Re va c- relef a se kNon va Ive s a Iso seen a co k " ~ c b O L f" h ct n) a)brnb, cal close when c% ka, a mek pressure _ i ncrea,ses to I 5 sa Th e- Vacuum rel,'e f va Ive c a re. nermall clese) f a4 a dAren~ .a I and are cles.y ed +c she+ cpe n ,

The Yn cuum relue[ VNues aIGc f re ssure of C . I fs Y.. C'rN*rnC-Iea Na C- S' *

frovcNc. ct pryd ve[s from ]:he b,arroer Q}a'nSNconha.nme b Ibo Abe-O m}S'mcS

nnulv.S un)er norma I unN ct ecachenh Con .ho o n S .

1 SEQUOYAH . UNIT 1 B 3/4 6-6 Revised 08/18/87 BR l

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. i INDEX p -

LIMITING CONDITIONS FOR OPERATION AND SURVEILLANCE REQUIREMENTS SECTION PAGE I 3/4.6.3 CONTAltiMENT ISOLATION VALVES. ... . ..... ..... ..... 3/4 6-17 l 3/4.6.4 COMBUSTIBLE GAS CONTROL Hydrogen Monitors......... ........ . .............. .... 3/4 6-24 Electric Hydrogen Recombiners. ... . ... ....... ....... 3/4 6 Hydrogen Control Interim Distributed Ignition System..... 3/4 6-26 3/4.6.5 ICE CONDENSER Ice Bed.. .......... ...... . .. .... ........ . ....... 3/4 6-27 Ice Bed Temperature Monitoring System.... ...... . ...... 3/4 6-29 s

Ice Condenser Doors... ... . .. ... .. . ................ 3/4 6-30 Inlet Door Position Monitoring System... .. .............. 3/4 6-32 Divider Barrier Personnel Access Doors and - '

Equipment Hatches... ................................... 3/4 6-33 .

Containment Air Return Fans.. ..... .. ....... ........... 3/4 6-34 Floor Drains......... ..... . .. ................. ....... 3/4 6-35 Refueling Canal Drains.................................... 3/4 6-36 Divider Barrier Seal...... . ......... . .. . .... .. 3/4 6-37 e s ystre % ,x 3/4.6.6 VACUUM RELIEF #MNE&. .We:'. . . . .. ................... 3/4 6-39 3/4.7 PLANT SYSTEMS 3/4.7.1 TURBINE CYCLE Safety Valves....... .. ... .. . ... .., ........ 3/4 7-1 Auxiliary Feedwater System. . . . .. ........... .... ... 3/4 7-5 Condensate Storage Tant.. ....... .. .. .. .... 3/4 7-7 3/4 7-8 Ac ti vi ty. . . . . . . . . .. ... .... .. . ....... ... ,

1 Main Steam Line Isolation Valves. ........ ... . .. .. 3/4 7-10 l l

'/4.7.2 STEAM GENERATOR PRESSURE / TEMPERATURE LIMITATION.... . 3/4 7-11 3/4.7.3 COMPONENT COOLING WATER SYSTEM.. . . . .. ..... 3/4 7-12 1

1 1

SEQUOYAH - UNIT 2 VIII !

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INDEX

) BASES SECTION PAGE

.3/4.4.6 REACTOR COOLANT SYSTEM LEAKAGE. . . . . . . . . . . . . . . . . . .B. .3/4 . . .4-4 3/4.4.7 CHEMISTRY...... ...... . . ... ....... .. ..... ....... B 3/4 4-5 '

3/4.4.8 SPECIFIC ACTIVITY..... ... ... ...... .... ..... ......... B 3/4 4-5 3/4.4.9 PRESSURE / TEMPERATURE LIMITS..... . ...

........... ..... B 3/4 4-6 3/4.4.10 STRUCTURAL INTEGRITY.. . ... . ........ .... ....... ... . B 3/4 4-14 3/4.4.11 REACTOR COOLANT SYSTEM HEAD VENTS....... ..... ....... B 3/4 4-15 R147 3/4.4.12 OVERPRESSURE PROTECTION SYSTEMS. ...... . ..... ......... B 3/4 4-15 3/4.5 EMERGENCY CORE COOLING SYSTEMS 3/4.5.1 ACCUMULATORS...............

............ .......... ....... B 3/4 5-1 k 3/4.5.2 and 3/4.5.3 ECCS SUBSYSTEMS........ .... .. ............... B 3/4 5-1 F 3/4.5.4 BORON INJECTION SYSTEM........ ............................ B 3/4 5-2 3/4.5.5 REFUELING WATER STORAGE TANK... ............... ........... B 3/4 5-2 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 CONTR0L.................... ..... ......... B 3/4 6-3 3/4.6.5

................. B 3/4 6-4 ICE CONDENSER..... > ..... $..............

3/4.6.6 VACUUM RELIEF"(AtVE5....... &............... ................ B 3/4 6-6 3/4.7 PLANT SYSTEMS 3/4.7.1 TURBINE CYCLE........................................ ..... B 3/4 7-1 3/4.7.2 STEAM GENERATOR PRESSURE /TEMERATURE LIMITATION............. B 3/4 7-3 3/4.7.3 COMPONENT COOLING WATER SYSTEM.............. .. ...... ... B 3/4 7-3 SEQUOYAH - UNIT 2 XIII Amendment No.147 1 March 30, 1992

CONTAINMENT SYSTEMS SURVfill ANCE REOUIREMENTS (Continued)

)

4.6.3.2 Each isolation valve specified in Table 3.6-2 shall be demonstrated OPERABLE during the C0l.0 SliUT00WN or REFUELING MODE at least once per 18 months by:

a. Verifying that on a Phase A containment isolation test signal, each Phase A isolation valve actuates to its isolation position.

b. Verifying that on a Phase B containment isolation test signal, each Phase B isolation valve actuates to its isolation position

c. Verifying that on a Containment Ventilation isolation test signal, each Containment Ventilation Isolation valve actuates to its isolation position. g. }gg u-~ -

d. bAMy i ng - t ha t-on+ h igh-con t a inne n t-p res sursi s ola tion 4e r,t-sJgna l '

R72

-each-Con t et i nmen t-Va c uum - R eMe f -Va l-v e-ac t ua t es- to-i t s-i sol a t-i on-

-po r,iti on,

e. Verifying that on a safety Injection test signal that the Normal Charging Isolation valve actuates to its isolation position. R90 4.f>.3.3 The isolation time of each power operated or automatic valve of f able 3.6-2 shall be determined to be within its limit when tested pursuant to Specification 4.0.5, m.

R109 ,

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SEQUDYAH - UNIT ? 3/4 6-18 Amendment No. 72, 90, 104 M9 July 5, 1989

TABLE 3.ts #(Continued) s' .

h CONTAINMENT ISOLATION VALVES VALVE NUMBER FUNCTION MAXIMUM ISOLATION TIME (Seconds) l C. PHASE "A" CONTAINMENT VENT ISOLATION (Cont.)

C

' $ 13. FCV-30-50 Upper Compt Purge Air Exh 4*

, 14. FCV-30-51 Upper Compt Purge Air Exh 4* R~62

15. FCV-30-52 Upper Compt Purge Air Exb 4*

16. FCV-30-53 Upper Compt Purge Air Exh 4*

17. FCV-30-56 Lower Compt Purge Air Exh 4*

18. FCV-30-57 Lower Compt Purge Air Exh 4*

19. FCV-30-58 Inst Room Purge Air Exh 4*

20. FCV-30-59 Inst Robm Purge Air Exh 4*

21. FCV-90-107 Cntmt Bldg LWR Compt Air Mon 5*

22. FCV-90-108 Cntmt Bldg LWR Compt Air Mon 5*

23. FCV-90-109 Cntmt Bldg LWR Compt Air Mon 5*

w 24. FCV-90-Il0 Cntmt Bldg LWR Compt Air Mon 5* i 1 25. FCV-90-Ill Cntmt Bldg LWR Compt Air Man 5*

cn 26. FCV-90-ll3 Cntmt Bldg UPR Compt Air Mon 5*

A

27. FCV-90-Il4 Cntmt Bldg UPR Compt Air Mon 5*

28. FCV-90-Il5 Catmt Bldg UPR Compt Air Man 5*

29. FCV-90-Il6 Cntmt Bldg UPR Compt Air Mon 5*

30. FCV-90-Il7 Cntmt Bldg UPR Compt Air Mon 5*

y ca D. OTHER N$

1. FEV-30-45 Veetium-ReHef Isolation Valve 25 -

2. FGV-30-47 Vacuum Relief Isolatten-Valve 25 55

--3. f4V-30-48 Y2cuum Rel4cf belatica -Valvc 25 R90

-k FCV-62-90 Normal Charging Isolation Valve 12 i M

U

Provisions of LCO 3.0.4 are not applicable if valve is secured in its isolated position with power removed

'm and leakage limits of Specification 4.6.1.1.c are satisfied. For purge valves, leakage limits under g3f7 P surveillance Requirement 4.6.1.9.3 must also be satisfied.

Provisions of LCO 3.0.4 are not applicable if valve is secured in its isolated position with power removed R29 and either FCV-62-73 or FCV-62-74 is maintained operable.

- This valve is required after completion of the associated modification. g73

_ __=- _. _ .- ._ _ _ _ - _ _ _ _ - _ _ _ _ _ _ _ _ _ - _ _ _ _ - _ _ _ _ - _ _ _ _ _ .

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. CONIAINMENT SYSTEMS fj)gg5 3/q f-3') ADO 3l+ b-40

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3/4.6. VACUUM REllEF VALVES ; '

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UMITING Cht{0lil0N FOR OPERAT]ON l 3

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3.6.6 The primdry containment vacuum relief valves shall be OPERABLE wj h an actuation set point of less than or equal to 0.1 psid. /

APPLICABILITY: MOD $5 1, 2, 3 and 4,

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ACTION: 'N

\

With one primary containmhot vacuum relief valve inoperable, 'estore the

' valve to OPERABLE status wkhin 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months or be in at least F T STANDBY within thenext6hoursandinCOLD\{iiUIDOWNwithinthefollowin/30 hours.

s .

SURVEILLANCE REQUIREMENTS x ,

i 4.6.6 No additional Surveillance Requ et ther than those required by

}+

Specification 4.0.5.

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1 SEQUOYAH - UNIT 2 3/4 6-39 l

l CONTAIt{ MENT SYSTEMS 3/4,6.6 VACUUM RELIEF SYSTEM 1,IMITING CONDITION FOR OPERATION 3.6.6 Each primary containment vacuum relief line shall be f OPERABLE.

APPLICABILITY: MODES 1, 2, 3, 4.

ACTION:

a. With one or more lines with one valve incapable of performing its containment isolation function, restore the valve in the af fected line (s) to OPERABLE status '

within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months ,

b. With one or more lines with both valves incapable of performing their containment isolation function, restore at least one valve in the af fected line (s) to OPERABLE status within 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in COLD SHUTDOWN

. within the following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months .

c. With one line incapable of performing its vacuum relief

, function, restore the inoperable line to OPERABLE 3

status within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months or be in at least HOT STANDBY 2 within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months ,

d. With two or more lines incapable of performing a vacuum relief function, restore the inoperable lines to OPERABLE status within 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months or be in at least HOT STANDBY withing the next 6 houls and in COLD SHUTDOWN 3

within the following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months , i

1 SEQUOYAH - UNIT 2 3/4 6-39 l 1

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CONTAINMENT SYSTEMS SURVEILLNICE REOUIREMENTS i

y 4.6.6 In addition to the requirements of Specification 4.0.5, demonstrate OPERABILITY at least once per 18 months by:

a. Verifying that on a high containment pressure isolation l test signal, each containment vacuum relief isolation valve actuates to its isolation position, and, 2

b. Verifying the opening setpoint of each vacuum relief valve is less than or equal to 0.1 psid.

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SEQUCYAH - UNIT 2 3/4 6-40 i

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CONTAINMENT SYSTEMS ,

BASES 3/4.6.5.7 and 3/4.6.5.8 FLOOR AND REFUELING CANAL DRAINS The OPERABILITY of the ice condenser floor and refueling canal drains ensures that following a LOCA, the water from the melted ice and containment spray system has access for drainage back to the containment lower compartment and subsequently to the sump. This condition ensures the availability of the water for long term cooling of the reactor during the post accident phase.

3/4.6.5.9 DIVIDER BARRIER SEAL The requirement for the divider barrier seal to be OPERABLE ensures that t

a minimum bypass steam flow will occur from the lower to the upper containment compartments during a LOCA. This condition ensures a diversion of steam through the ice condenser bays that is consistent with the LOCA analyses.

m 3/4.6.6 VACUUM RELIEF VALVEfr '"-"

r SYSTEwQ

-s nnes) %._The OPERABILITY of the primary containment to-otm*phere vacuum v'

relief' valves ensures that the containment internal pressure does not become more negative than 0.1 psid. This condition is necessary to prevent exceeding the containment design limit for internal vacuum of 0.5 psid. A l nc con . sis +x of a va cu u rn rc IIe f isola N n VaI'L > " Vacourn rcIIb VOC > 9 f'"],

and. a ssociahc[ i n s-f ro w enYcd e n ""d O' faIS-The v ac ouavt re I' eI * l"+'* " V" 1V' 5 J #f* "" " rL

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predockG S"~ ' Q gonc]kl ens' .

vack tr O SEQUOYAH - UNIT 2 8 3/4 6-6 Revised 08/18/87 BR December 7, 1990p,r.- ^ r; 'F C ] .

ENCLOSURE 2 PROPOSED TECIINICAL SPECIFICATION CilANGE SEQUOYAll NUCLEAR PLANT UNITS 1 AND 2 DOCKET NOS. 50-327 AND 50-328 (TVA-SQN-TS-93-04, REVISION 1)

DESCRIPTION AND JUSTIFICATION FOR CilANGES TO CONTAINMENT VACUUM RELIEF SPECIFICATION 3/4.6.6 SURVEILLANCE REQUIREMENT 4.6.3.2.d.

TABLE 3.6-2, AND BASES 3/4.6.6

4 I

Reactintian_of_ Change TVA proposes to revise the Sequoyah Nuclear Plant (SQN) Technical

Specification (TS) 3/4.6.6, "Vacumn Relief Valves," for the purpose of 1 combining operability requirements associated with the dual function of l SQN's vacuum relief (VR) system into a single TS. SQN's VR system is I designed to perform a dual design function for both containment isolation and VR, i The proposed specification for SQN's VR system (TS 3/4.6.6) includes a new limiting condition for operation (LCO) that requires each containment VR 11ne to be operable. Each line consists of a VR isolation valve, a VR valve, piping, and associated instrumentation and controls. The new LCO establishes the minimum equipment required for these VR lines to accomplish the VR function and the containment isolation function. The modes of applicability in the proposed specification are Modes 1, 2, 3, and 4. The proposed action requirements are stated below

a. With one or more lines with one valve incapable of performing its containment isolation f unction, restore the valve in the af fected 3

line(s) to operable status within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months or be in at least hot standby within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in cold shutdown within the

. following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months .

b. With one or more lines with both valves incapable of performing their containment isolation function, restore at least one valve in the affected line(s) to operable status within 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months or be in at least hot standby within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in cold shutdown within the following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months .

i

c. With one line incapable of performing its VR function, restore the inoperable line to operable status within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months or be in at least.

hot standby within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in cold shutdown within the

following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months .

a

d. With two or more lines incapable of performing a VR f unction, restore the inoperable line to operable status within 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months or be in at least hot standby within the next 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and in cold shutdown within the following 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months .

l The proposed specif1 cation incorporates surveillance requirements (SRs) that cite the in-service test (IST) program requirements. In addition to the IST program requirements, operability of the valves is demonstrated i every 18 months by:

a. Verifying that on a high containment pressure isolation test signal, each containment VR isolation valve actuates to its isolation position, and, t

y y-wr += 'N+ # e -r --m-- - - - *r ' ' * - - - - ~ > -'**+- -*- - - - ' ' = - - - * * ' - - - - - - - - - - - - -

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b. Verifying the opening setpoint of each VR valve is less than or equal to 0.1 pounds per square inch differential (psid).

The first 18-month SR (Item a above) is currently located in the containment isolation valve section of SQN TSs (SR 4.6.3.2.d). TVA's proposed change deletes this SR from the containment isolation valve specification and relocates it into the proposed VR system specification as SR 4.6.6.1.a.

The second 18-month SR (Item b above) is an SR that is currently governed at SQN by the requirements of Specification 4.0.5 (i.e.,Section XI of the American Society of Mechanical Engineering [ASME] Boiler and Pressure Vessel Code). TVA's proposed change retains this SR as a specific

SR (4.6.6.1.b) in addition to the provisions .of SR 4.0.5.

In conjunction with the proposed changes described above, SQN's VR isolation valves (FCV-30-46, -47, and -48) have been deleted from the TS Table ~3.6-2 and transferred to the proposed VR system Specification 3/4.6.6. TVA revised the title for Bases 3/4.6.6 from

" Vacuum Relief Valves" to " Vacuum Relief System." The TS index pages i have been revised to reflect this titic change. Infonnation has been added to Bases 3/4.6.6 to clarify the dual function of SQN's VR valves and VR isolation valves.

Reason. fur _ Change On July 28, 1992, TVA discovered that the configuration of the air supplies and solenoids for SQN's containment VR isolation valves (air-operated butterfly valves) would result in the loss of guaranteed automatic closure capability upon the unavailability of Train A essential control air, rendering the valves inoperable for containment isolation.

Since Train A essential control air has been unavailable at times over the operating life of the plant without applying the action provisions of TS 3.6.3 to the VR isolation valves, it was concluded that the plant has

technically operated in a condition prohibited by TSs. This finding was reported to NRC in Licensee Event Report (LER) 50-327/92015 dated i August 27, 1992. Two corrective actions were identified in Section V of j the LER. The first action involved establishing _an interim compensatory action to maintain operability of the valves during periods when Train A essential control air is unavailable. The second corrective action involved preparing a TS change to clarify the dual design function of SQN's VR system so that TSs can be satisfied without the need for the compensatory action. l In addition, the TS requirements for SQN's VR isolation valves are governed by Specification 3/4.6.3, " Containment Isolation Valves," while

, the TS requirements for the vacuum relief valves are governed by Specification 3/4.6.6, " Vacuum Relief Valves." Under certain scenarios, the required TS actions for fulfilling the dual design functions would f

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present conflicting requirements. Combining these TS requirements into a single specification -is necessary to provide clear guidance to the operator and eliminate the potential for misinterpretation regarding the required actions associated with SQN's VR system.

Juatification_for_ Change The SQN VR system is designed to protect the free-standing steel

- containment vessel from excessive external force in the event an overcooling or depressurization transient occurs inside containment. The system is sized to ensure that the external pressure differential on the containment vessel does not exceed 0.5 paid.

System

Description:

The VR system consists of three identical VR flow paths, each comprised of a self-actuating VR valve, a pnemnatically operated isolation valve, associated piping, and instrumentation and controls.

The three VR lines are located in the annulus between the primary steel containment vessel and the shield building. The containment penetration numbers associated with these units are X-111, -112, and -113. The VR valve is located outboard of the isolation valve as shown on Final Safety

Analysis Report (FSAR), Figure 6.2.4-17.

Each VR valve is a 24-inch, spring-loaded, swing-disc (check) valve with an elastomer seat. The valve is normally closed and is equipped with limit switches that provide fully open and fully closed indication in the main control room (MCR). This instrumentation is designed in accordance

=

with Regulatory Guide (RG) 1.97. The VR valve is designed to start opening at a differential pressure of 0.1 paid and to be fully open for a VR system design basis event.

Each VR 1 solution valve is an air-operated butterfly valve with an

! elastomer seat. Two separate trains of control air are provided to the-two separate solenoid valves that control the air supply power to the isolation valve. The isolation valves are normally open, fall-open, and close when the containment pressure increases to-the high set pressure of 1.5 pounds per square inch gauge (psig). This isolation signal is developed from either of two independent sets of three pressure sensors

, and is completely independent of other containment isolation signals.

l Fully open and fully closed positions are indicated in the MCR.

Automatic closure of the isolation valve is annunciated in the MCR.

A complete description of the design function for this system is provided i in the SQN FSAR, Section 6.2.6.

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Design Bases:

The SQN VR system is designed to mitigate the following abnormal operational occurrences:

1. Inadvertent containment spray actuation

2. Inadvertent containment air return fan operation

3. Simultaneous occurrence of inadvertent spray and air return fan operation Two of the three VR lines are required to mitigate the limiting external differential pressure event (inadvertent spray actuation).

The VR system la not required to actively mitigate a loss-of-coolant accident (LOCA) or any other accident scenario that might result in the release of radioactivity inside containment. As an extension of the primary containment boundary, the VR system provides a barrier against icakage of airborne fission products from the containment atmosphere under normal and accident conditions. The isolation valves are designed to isolate automatically to provide positive containment isolation upon sensing containment pressure greater than or equal to 1.5 psig. The outboard self-actuating check valves are normally closed.

The system is designed to withstand a safe-shutdown earthquake without failure.

Justification:

1 As discussed in NUREG-1232, Volume 2, page 3-57, the greater safety function of the VR penetrationc and associated isolation valves is to protect the containment vessel from collapse (depressurization relative to the annulus) and hence, total loss of containment integrity. Based on NRC's evaluation, an exemption to 10 CFR 50, General Design Criteria 56, ,

was granted for this unique dual-purpose system. The basic conclusion is that the VR penetrations are designed to ensure containment integrity from both an external and internal pressurization event, and the end result is the assurance of containment integrity for all postulated events. As stated in NUREG-1232, "The staff concludes that for Sequoyah, Cue in part to its low capability to sustain reverse differential pressures, the fail-open position of the butterfly isolation valves is neceptabic."

. The loss of Train A essential control air to the air-operated butterfly isolation valves, as described in LER 50-327/92015, does not result in the loss of containment integrity. The butterfly valves are designed to fail-open from loss of air. Without Train A air, the butterfly isolation valves (air to close) remain in their fall-safe design position (fully

, open) to fulfill the primary function of VR for the containment vessel. ,

The loss of Train A air results in the butterfly isolation valves 1 remaining fully open (with or without Train A single failure). Assuming a single failure occurs to the Train B air supply, the butterfly ;

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1

-S-isolation valves would continue to remain in their fail-safe design position (fully open) since Train B air would not be available to close the valve.

j With the butterfly valves open, the normally closed spring-loaded VR 1

check valves would serve as the barrier for containment isolation in the event of an accident. These VR check valves are designed to provide a quallffed containment boundary against leakage of airborne fission products from the containment atmosphere under normal and accident

conditions. Each check valve is leak tested in accordance with 10 CFR 50, Appendix J (Type C test), to ensure the total combined leakage rate from all containment penetrations remains within the maximum allowable leakage rate (0.60 L a). The containment leak rate assumed in the worst-case design basis accident analysis (LOCA) bounds the 0.60 L, leakage limit. In addition, positive valve position indication is provided in the MCR. The valves are not powered from any electrical source; therefore, no spurious signal or inadvertent operator action could initiate opening these valves. The valves are held closed by a spring force during periods of normal containment pressure and would experience additional closing force from a pressurization event inside containment. Accordingly, containment integrity is maintained by the VR valves while the VR isolation valves remain open.

With regard to the current TS Action Statement 3.6.3.b, the condition described in LER 50-327/92015 (loss of Train A air) would require the affected VR line(s) to be isolated within four hours or begin unit shutdown. Action Statement 3.6.3.b would involve closing the affected air-operated butterfly isolation valve (s) and removing electrical power from the valve (s) to fulfill the isolation requirement for the affected penetration "by use of at least one deactivated automatic valve sacured in the isolation position." This action to isolate is undesirable and is in conflict with SQN TS 3/4.6.6 that requires operability of SQN's VR system. To appropriately address provisions for continued operation for these VR lines, TVA proposes to revise Specification 3/4.6.6 for the VR valve to combine the containment isolation requirements and the VR requirements into one specification. This approach is similar to that used in the standard TSs (STSs) for boiling water reactors (BWRs) l (reference NUREG 4433. BWR/4 STS dated September 28, 1992).

The BWR/4 STSs for reactor building to suppression chamber vacuum breakers (see LCO 3.6.1.7) contain LCO requirements, action statements, 1 and SRs that address both the containment isolation function and VR )

function in a single stand-alone specification. TVA's proposed change to Specification 3/4.6.6 establishes similar requirements that are based on maintaining the VR system functional for both containment isolation and i VR. TVA's proposed Action Statements a and b have been broken down to address the operability of the lines in terms of the valves and their capability of performing their containment isolation function. The restoration timeframes for returning a valve or valves to operable 4

i

status when they are incapable of performing containment isolation functions have been established as 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months for one valve and I hour for two valves (applies to one or more lines). The 72-hour completion time for one valve inoperable was selected to be consistent with the Westinghouse STS for VR valves (ref er to LCO 3.6.12 of NUREC-1431). The 1-hour completion time for two valves inoperable was selected to be consistent with the Westinghouse STS for containment isolation valves (refer to LCO 3.6.3 of NUREG-1431).

TVA's proposed Action Statements e and d have been designed to address operability in terms of the capability of the line or lines to perform the VR function. The restoration timeframes for returning a line or lines to operable status when they are incapable of performing a VR function have been established as 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months for one line and 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months for two lines. By design, three VR lines'are required to be operable to ensure that at least two are available for containment protection (assumes single failure). The 72-hour and 1-hour action timeframes were selected to remain consistent with NUREG-1431 and NUREG-1433 and other existing LCOs when the loss of one train of a safety system is assumed.

In the event that a VR line cannot be restored to operable status within the required completion time, the plant must be brought to a mode in which the LCO does not apply. To achieve this status, the plant must be brought to at least Mode 3 (hot standby) within 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and Mode 5 (cold shutdown) within 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months . The allowed completion times are consistent with Westinghouse STS NUREG-1431 and are reasonable, based on operating experience, to reach the required plant conditions from full-power conditions in an orderly manner and without challenging plant systems.

The SRn for TVA's. newly proposed Specification 3/4.6.6 refer to Specification 4.0.5 for the IST requirements (ASME Boiler and Pressure Vessel Code and applicable addenda). At SQN, both the VR and the VR isointion valves are in the IST program. It should be noted that for the VR valves, the SQN IST program adopts the ANSI /ASME OM-1-1981,

" Requirements for Inservice Performance Testing of Nuclear Power Plant Pressure Relief Devices." ANSI /ASME OM-1-1981 requires that VR valves be

. . . actuated to verify open and close capability, set pressure, and performance of any pressure and position sensing accessories." At SQN, this testing is performed on the VR v>1ves every six months unless historical data indicates a requiremeit for more frequent testing. This testing is accomplished under SQN M ye111ance Instruction (SI) 62,

" Primary Containment Vacuum Relief Valve Auto-Open." In addition, the VR isolation valves are tested in accordance with SQN's IST program to ensure that the isolation times for each valve are within their limit.

This testing is performed every 92 days under SQN SI-166, " Summary of Valve Test for ASME Section XI."

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- . . . . . - ~__.-_.- -. - - _ - - - - - - - .

l In addition to the testing requirements of Specification 4.0.5, TVA has added two SRs with an 18-month frequency. The first SR in a functional test of the containment VR isolation valves to ensure that on a high-containment pressure signal, each containment VR isolation valve actuates to its isolation position. This test currently exists as SR 4.6.3.2.d in the contaitunent systems section of SQN TSs and has been relocated to the newly proposed VR system specification as SR 4.6.6.1.a.

i The second SR is a functional test of the VR valves to ensure that the opening setpoint of each VR valve is less than or equal to 0.1 psid.

This test is currently performed every six months as part of SQN's IST program (i.e., OM-1-1981) under SI-62 and is being retained in the TS.

The current six-month test frequency will be maintained for compliance with the IST program requirements.

1 In conjunction with the proposed changes to TS 3/4.6.6, TS requirements

! associated with SQN's VR isolation valves (FCV-30-46, ~47, and -48) have been deleted from the containment isolation valve specification (TS Table 3.6-2 and SR 4.6.3.2.d) and transferred to proposed Specification 3/4.6.6 for the VR system. The removal of these valves from Table 3.6-2 for containment isolation valve is consistent with the approach provided in NRC Generic Letter 91-08, " Removal of Component Lists From Technical Specifications (Generic Letter 91-08)." The SQN VR isolation valves are contained in a plant procedure (SI-166) that is subject to the change control provisions for plant procedures in the

, administrative controls section of the TSs (i.e., change control provisions of 10 CFR 50.59). In addition, these valves are listed in j '

SQN's IST program that is contained in Section 6.8 of the.SQN FSAR.

Since the removal of SQN's VR isolation valves from TS Table 3.6-2 does not alter existing TS requirements for these valves (i.e., [1]

postmaintenance testing, [2] demonstrating automatic closure on isolation signals, and [3] confirming the isolation time of the valves), the proposed change 18 justified. The deletion of SR 4.6.3.2.d is also justified since this SR for demonstrating automatic closure on isolation signals is retained as SR 4.6.6.1.a in the proposed Specification 3/4.6.6 for the VR system.

, in conclusion, TVA's proposed change provides a TS improvement that ,

eliminates the potential for conflicts between existing TS requirements regarding the dual design function of SQN's VR system. In addition, TVA's proposed changes remain consistent with Westinghouse STS/NUREG-1431 and BWR/4 STS/NUREG-1433 for action requirements and sRs associated with both the containment isolation and the VR functions of SQN's VR system. ,

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Entdr9muntaLimpac_Llvaluation The proposed change request does not involve an unreviewed environmental 4 question because operation of SQN Units 1 and 2 in accordance with this change would not:

1. Result in a significant increase in any adverse environmental impact previously evaluated in the Final Environmental Statement (FES) as modified by NRC's testimony to the Atomic Safety and Licensing Board, supplements to the FES, environmental impact apprainals, or decisions of the Atomic Safety and Licensing Board.

2. Result in a significant change in effluents r power levels.

3. Result in matters not previously reviewed in the licensing basis for SQN that may have a significant environmental impact.

1 l

& 4 e --- -- e M a- r Enclosure 3 PROPOSED TECilNICAL SPECIFICATION CilANGE SEQUOYAll NUCLEAR PLANT UNITS 1 AND 2 DOCKET NOS. 50-327 AND 50-328 (TVA-SQN-TS-93-04, REVISION 1)

DETERMINATION OF NO SIGNIFICANT IIA 2ARDS CONSIDERATION u

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

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

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

'IVA's proposed changes do not involve a significant increase in the probability or consequences of an accident previously evaluated. The proposed change does not increase the probability of an accident since the proposed change does not affect any plant systems, equipment, or components. The dual design functions of SQN's containment vacuum relief (VR) system (i.e., provide containment VR and containment isolation) are not affected. The consequences of an event are not significantly increased by the proposed increase in allowed outage time from 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months to 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months for returning an inoperable VR system to operable o'atus. The probability of an event during the relatively short duration of the TS completion times, in conjunctton with the redundancy provided in the design of the syster provide sufficient assurance that the VR lines are available for mitigating an accident or abnormal event.

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

No physical modification is being made to any plant hardware or plant operating setpoints, limits, or operating procedures as a result of this change. TVA's proposed change provides a TS improvement that clarifles the TS requirements associated with the dual design function of SQN's VR system. The proposed change removes the potential for creating a conflict between Specification 3/4.6.3,

" Containment isolation Valves," and Specification 3/4.6.6, " Vacuum Relief Valves."

The proposed change does not alter any accident analysis or any narnimptions used to support the accident analyses. The containment leakage assumptions used to determine of f site dose limits for compliance with 10 CFR 100 are not affected. The analysis that supports the containment VR system also remains unchanged. The proposed 72-hour and 1-hour completion times for returning an inoperabic VR line to operable status are consistent with the NUREG-1431 and NUREG-1433. Consequently, the proposed change does not create the possibility of a new or different kind of accident Irom any previously analyzed.

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

The margin of saf ety provided by the design of SQN's containment VR system remains unchanged. TVA's proposed change does not affect the VR function or the containment isolation function that currently exists in SQN TSa. The proposed change eliminates the potential for conflicting requirements within SQN TSs and ensures that the proper action is taken to preserve these dual design functions while the plant is in Modes 1, 2, 3, or 4. TVA's proposed change provides a TS improvement that combines these functional requirements into a single specification. Both VR and containment isolation requirements will continue to be provided. Accordingly, the proposed change does not involve a reduction in the margin of safety.

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ML20070Q921

Text

Description:

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