ML20082E607
ML20082E607 | |
Person / Time | |
---|---|
Site: | Sequoyah |
Issue date: | 04/06/1995 |
From: | TENNESSEE VALLEY AUTHORITY |
To: | |
Shared Package | |
ML20082E601 | List: |
References | |
NUDOCS 9504110278 | |
Download: ML20082E607 (16) | |
Text
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^4 l- 8 ENCLOSURE 1 i
, . PROPOSED TECHNICAL SPECIFICATION.(TS) CHANGE-SEQUOYAH NUCLEAR PLANT (SON) UNITS 1 AND 2 -
DOCKET NOS. 50-327 AND 50-328 (TVA-SON-TS-94-19) f i
LIST OF AFFECTED PAGES Unit 1' 3/4 8-1 3/4 8-2 B 3/4 8-1 Unit 2 3/4 8-1 3/4 8-2 '
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ELECTRICAL POWER SYSTEMS
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3 /4 '. 8.'1 A.C. SOURCES OPERATING LIMITING CONDITION FOR OPERATION j I
3.8.1.1 'As a minimum, the following A.C. electrical power sources shall be 'l OPERABLE: :
- a. Two physically independent circuits between the offsite transmission network and the onsite Class 1E distribution system, and ;
- b. Four separate and independent diesel generator sets each with:
- 1. Two diesels driving a common gerierator
- 2. Two engine-mounted fuel tanks containing a minimum volume of 250 gallons of fuel, per tank
- 3. A separate fuel storage system containing a minimum volume of 62,000 gallons of fuel,
- 4. A separate fuel transfer pump, and
- 5. A separate 125-volt D.C. distribution panel,125-volt D.C.
'-- battery bank and associated charger.
APPLICABILITY: MODES 1, 2, 3 and 4.
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A V N ACTION:
o., (Ado ArnnHED ~I NSE8T N With cither :n eff it circuit r diesel generator set (s) 1A-A and/or R136 bY/.
2A-A or 18-B and/or 2B-B of the above required A.C. electrical power sources inoperable, demonstrate the OPERABILITY of the remaining A.C.
sources by performing Surveillance Requirement 4.8.1.1.L a withi_n gne. '
gio4 hour and at least once.per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> thereafter, andfSurveillance Requirement 4.8.1.1.2.a.4 within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />; restore at least tw; cff it:
cicc.its a,,d four diesel generator sets-to OPERABLE _ status within R141 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />
- or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in l COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.
DETERIn/NINs OPEL6 LE bnesa. GauguTD4 Sers kk No7' INOl' ETA 6LE DUE TO 00pH710A) h/9ilSC [AN.dN Ok k]WMI e Reaulco Tnonust.s nerious vemy oveusur To cc,Heov Das Yo duct. scuexent Cnuse Firittier sers or kmxm sx au o-1.t././.z.a.y>gM
- Q ConnEnv2 ff& nom rs EmnED. -
- R141
- The 72-hour action statement may be extended for an additional 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> for
. one train of diesel generators (either 1A-A and 2A-A, or 1B-B and 2B-B) during
) the performance of Surveillance Requirement 4.8.1.1.2.f.1. A temporary fuel
- supply must be connected to the diesel generator set that is having the associated fuel tanks cleaned.
SEQUOYAH - UNIT 1 3/4 8-1 Amendment No. 100 ,132,137 April 27, 1990
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. . INSERT A: With one offsite A.C.' circuit of the above required A.C. electrical ;
power sources inoperable, demonstrate the OPERABILITY of the -
remaining offsite A.C. circuit by performing Surveillance l
+ -Requirement 4.8.1.1.1.a within one hour and at least once per 8 )
hours thereafter. Restore at least two offsite circuits to i OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or be in at least HOT d STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />. i l
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ELEdTRICALPOWERSYSTEMS1
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' ACTION"(Continued)~
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- C[ 'With one offsite circuit and.one diesel generator set of the:above: J required A.C. electrical power sources inoperable, demonstrate.the: .;
OPERABILITY of the' remaining A.C. sources by performing Surveillancei.
-Requirements 4.8.1.1.1.a withinione~ hour and at least once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> thereafter, and. Surveillance Requirement 4.8.1.1;2.a.4.within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />; R104 ]N '
- restore at least-one of;the inoperable sources to.0PERABLE status ~.
a within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> or be in at least HOT STANDBY.within the,next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN.within the following.30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />. Restore at least- ~ O d
two offsite1 circuits and four diesel generator sets to~0PERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> from the time of initial: loss'or beiin at least HOT' STANDBY within the next_6 hours and in COLD SHUTDOWN within the?
following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.
- 1 d g. With two of the above. required offsite A.C. circuits inoperable, demonstrate the-OPERABILITY of 4' diesel generator sets by performing R10'4 Surveillance Requirement 4.8.1.1.2.a.4 within;8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />, unless the-diesel. generator sets are already operating; restore at least.one of-the inoperable.offsite sources to OPERABLE status within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />'or: d i
be in'at-least HOT STANDBY within the.next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. :With only:one offs'ite source restored, restore at least two'offsite circuits to:
OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> from time of initial. loss or be in at least HOT STANDBY within the next.6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN'within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.-
- e. g. With either diesel generator sets IA-A and/or 2A-A inoperable-simultaneous with IB-B and/or 2B-B, demonstrate the OPERABILITY' of.
two offsite A.C. circuits by performing Surveillance Requirement 4.8.1.1.1.a within one hour and at.least once per 8. hours thereafter; restore at least .1).1A-A and 2A-A or 2) IB-B and 28-8 to OPERABLE-status within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> or be in at least. HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD-SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.. Restore at least four diesel generator. sets to OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> from time of initial loss or be in least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.
i SURVEILLANCE RE0VIREMENTS 4.B.1.1.1 Each of the above required independent circuits between the offsite transmission network and the onsite Class 1E distribution system shall be: .
- a. Determined OPERABLE at least once per 7 days by verifying correct breaker alignments, indicated power availability, and j i
b.- Demonstrated OPERABLE at least once per 18 months during shutdown by R188
" ly from the transferring (manually and automatically) unit power unit generator supported circuit to the preferred power supp(GDC 17) l circuit.
4 July 11, 1994 <
3/4 8-2 Amendment No. 100, 137, 184 SEQUOYAH - UNIT 1
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r ;3/4.8 ELECTRICAL POWER SYSTEMS i I
BASES 3/4.8.1 and 3/4.8.2 A.C. SOURCES AND ONSITE POWER DISTRIBUTION SYSTEMS The OPERABILITY of the A.C. and D.C power sources and associated distri-bution systems during operation ensures that sufficient power will be available to supply the safety related equipment required for 1) the safe shutdown of the '!
facility and 2) the mitigation and control of accident conditions within the- 1 facility. The minimum specified independent and redundant A.C. and D.C. power -
sources and distribution systems satisfy the requirements of General Design
-Criteria 17 of-Appendix "A" to 10 CFR 50.
The ACTION requirements specified for the levels of degradation'of the power sources provide restriction upon continued facility operation commensur-ate with the level of degradation. The OPERABILITY of the power sources are consistent with the initial condition assumptions of the accident analyses and ;
are based upon maintaining at least one redundant. set of onsite A.C. and D.C.
power sources and associated distribution systems OPERABLE during accident .
conditions coincident with an assumed loss of offsite power and single failure t
.C. source.
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udiihn ON requirements are specified for performance of the chemi-cal cleaning required by Surveillance Requirement 4.8.1.1.2.f.1. The motor- R141 driven fuel pumps for the diesel generator set with the tanks.being cleaned -
will be temporarily connected to the underground storage tanks for the other
) diesel generator set with the same train designation. An additional fuel-oil.
inventory of approximately 68,000 gallons will be available in one of the yard -
- storage tanks prior to the start of the chemical cleaning of any underground
- storage tank. Within practical limits, the chemical cleaning of an underground storage tank will be performed during a refueling or other scheduled outage for the associated unit.
The OPERABILITY of the minimum specified A.C. and D.C. power sources and ;
associated distribution systems during shutdown and refueling ensure: that 1). ;
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the facility can be maintained in the shutdown or refueling condition for extended time periods and 2) sufficient instrumentation and control capability l is available for monitoring and maintaining the unit status.
The Surveillance Requirements for demonstrating the OPERABILITY of the- t diesel generators are in accordance with the' recommendations of Regulatory Guides 1.9 " Selection of Diesel Generator Set Capacity for Standby Power Sup-plies," March 10,1971, and 1.108 " Periodic Testing of Diesel Generator Units Used as Onsite Electric Power Systems at Nuclear Power Plants," Revision 1, -
August 1977, and 1.137 " Fuel-011 Systems for Standby Diesel Generators," Revi- l sion 1, October 1979. The surveillance requirements for the diesel generator :
load-run test and the 24-hour endurance and margin test are in accordance with Regulatory Guide 1.9, Revision 3, July 1993, " Selection, Design, Qualification, and Testing of Emergency Diesel Generator Units Used as Class 1E Onsite Elec- .
tric Power Systems at Nuclear Power Plants." During the diesel generator endurance and margin surveillance test, momentary transients outside the kw and
) kvar load ranges do not invalidate the test results. Similarly, during the ,
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diesel generator load-run test, momentary transients outside the kw load range i do not invalidate the test results. .
R177l SEQUOYAH - UNIT 1 B 3/4 8-1 Amendment No. 12, 137, 173 November 29, 1993 $
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. lNSERT B: The footnote for Action b of LCO 3.8.1.1 requires completion of a
' determination that the OPERABLE diesel generators are not -
g inoperable.due to common cause' failure or performance of Surveillance 4.8.1'.1.2.a.4 if Action b is entered. The intent is that all diesel generator inoperabilities .must be investigated for common cause failures regardless of.how long the' diesel -
. generator inoperability persists.
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- The' action to determine that the OPERABLE diesel ~ generators are -
not inoperable due to common cause. failure provides an
. allowance to avoid unnecessary testing of OPERABLE. diesel generators. 'If.It can be determined that the cause of the inoperable diesel generator does not exist on the OPERABLE diesel .
generators, Surveillance Requirement 4.8.1.1.2.a.4 does not have
- to be performed. if the cause.of inoperability exists on _other-diesel generator (s), the other diesel generator (s) would be
' declared inoperable upon discovery and. Action'e of LCO 3.8.1.1' would be entered as applicable. Once the common failure is repaired, the common'cause no longer exists, and the action to i determine inoperability due to common cause failure is satisfied.
If the cause of the initial inoperable diesel generator cannot be-confirmed not to exist on the remaining diesel generators,.
performance of Surveillance 4.8.1.1.2.a.4 suffices to provide assurance of continued OPERABILITY of the other diesel generators.
According to Generic Letter 84-15, 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> is reasonable to confirm that the OPERABLE diesel generators are not affected by.
the same problem as the inoperable diesel generator.
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'A.C.' SOURCES-T,y J' 3/4.8.1 *
. > OPERATING.
LIMITING CONDITION FOR OPERATION
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3.8.1.1 As.a minimum,- the following A.C. electrical power sources shall be'
. OPERABLE:
- a. ..Two physically independent circuits between the offsite transmission network and the onsite Class 1E distribution system, and
- b. Four separate-and independent diesel generator sets each with:
- 1. Two diesels driving a common generator- j
- 2. Two engine-mounted fuel tanks containing a minimum volume of. 1 250 gallons of fuel, per tank
- 3. -A separate fuel storage. system containing a minimum volume of M 62,000 gallons of fuel,
)
- 4. .A separate fuel transfer pump, and 5.. A separate 125-volt D.C. distribution panel,125-volt D.C. -;
e battery bank and associated charger.
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APPLICABILITY: . MODES 1, 2 3 and 4 I
, (Aoo Armt.H En 1NSEAT h ft. With eitt.or er, eff.it; cir;;it er diesel generator set (s):1A-A Rll
!l and/or 2A-A or 1B-B and/or 28-B of the above required A.C. electrical power sources inoperable, demonstrate the OPERABILITY of the remaining i A.C. sources by performing Surveillance Requirement 4.8.1.1.1.a within R89 one hour and at least once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> thereafter, and? Surveillance Requirement 4.8.1.1;2.a.4 within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />; restore at least ta eff;it; circuit; er.d four diesel generator sets to OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />
- or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in R123l. I COLD SHUTDOWN within the followina 30 hann -
rn9mwiss OPEREE besa_ Gaven.Aw. sers Mc Nor .Taoarsac ]
bus To Common CnusE ' FAlW6 O W ?ERfo Ul/NG 4R$ui.co penoa To vsRsF)/ DPEK# ALE' M/Ein.Connes MM M N Ngnsur. To of SA M / ^Suwar Couu- 2 A bat SMu. Con Tm EAMAb'D
- The 72-hour action ~ statement may be extended for an additional 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.for one train of diesel generators (either 1A-A and 2A-A, or IB-B and 2B-B) during the R123 I performance of Surveillance Requirement 4.8.1.1.2.f.1. A temporary fuel supply .i must be connected to the diesel generator set that is having the associated i a.
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fuel tanks cleaned. . !
3/4 8-1 Amendment No. 89,119,123 :
SEQUOYAH - UNIT 2 April 27, 1990 1
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. INSENT A: 'With one offsite A.C. circuit of the above required A.C. electrical power sources inoperable, demonstrate the OPERABILITY of the
,' remaining offsite A.C. circuit by performing Surveiliance -
l Requirement 4.8.1.1.1.a within one hour and at least once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> thereafter. Restore at least two offsite circuits to OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or be in'at least HOT-STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN-within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />. ;
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- ELECTRICAL: POWER' SYSTEMS'
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' ACTION (Continued)
With-one offsite circuit and one diesel-generator. set of the:above
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CM - required- A.C. electrical powere sources inoperable, demonstrate the' OPERABILITY of the remaining A.C. sources by~ performing Surveillance y T Requirements 4.8.1.1.1.a within one hour and:at least once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> x89 thereafter, and'SurveillanceLRequirement 4.8.1.1;2.a.4 within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />; restore at least one of the inoperable' sources to OPERABLE status .
-within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> or be in at least HOT STANDBY within the next 6' hours and in COLD: SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.. Restore at leastL two offsite circuits and four: diesel generator sets to OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> from the time of initial loss or be in at least. HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.
d /. With two of the above required offsite A.C.-circuits inoperable,_
demonstrate the OPERABILITY:of 4 diesel generator sets by performing as9 Surveillance Requirement 4.8.1.1.2.a.4 within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />,-unless the
' diesel generator sets are already operating; restore at least one of.
the' inoperable offsite sources to OPERABLE status within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> =or With-only one be in'at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.
offsite-source restored, restore at'least two offsite circuits?to
-OPERABLE status within 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />s- from time of initial loss or be in at-least HOT STANDBY within' the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />' and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />, With.either diesel generator sets IA-A and/or 2A-k-inoperable e f. simultaneous with IB-B and/or 28-B, demonstrate the .0PERA8ILITY .of two offsite A.C. circuits by performing Surveillance Requirement 4.8.1.1.1.a within one hour and at least once per 8-hours thereafter; restore at least 1). IA-A and 2A-A or 2) 18-8 and 28-B to OPERABLE status within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> or be in at least HOT STANOBY within theRestore:
next:
6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the fol10 wing 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.
.at.least four diesel generator sets to OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> from time of initial loss or be in least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in' COLD SHUTDOWN .within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.
SURVEILLANCE RE0UIREMENTS 4.8.1.l.1 Each of the above required independent circuits:between the offsite transmission network and the 'onsite Class IE distribution system shall be:
- a. Determined OPERABLE at least once per_7 days by verifying correct'-
breaker alignments, indicated power availability, and
. b. Demonstrated OPERABLE at least once per 18 months during shutdown by R176-transferring (manually and automatically) unit power supply from.the-unit generator supported circuit to the preferred power (GDC 17)- l circuit. ,
3/4 8-2 Amendment No. 89, 123 , 176 SEQUOYAH - UNIT 2 July 11, 1994-
3/4.8 ELECTRICAL POWER SYSTEMS BASES 3/4.8.1 and 3/4.8.2 A.C. SOURCES AND ONSITE POWER DISTRIBUTION SYSTEMS The OPERABILITY of the A.C. and D.C power sources and associated distri-bution systems during operation ensures that sufficient power will be available to supply the safety related equipment required for 1) the safe shutdown of the facility and 2) the mitigation and control of accident conditions within the facility. The minimum specified independent and redundant A.C. and D.C. power sources and distribution systems satisfy the requirements of General Design Criteria 17 of Appendix "A" to 10 CFR 50.
The ACTION requirements specified for the levels of degradation of the power sources provide restriction upon continued facility operation commensur-ate with the level of degradation. The OPERABILITY of the power sources are consistent with the initial condition assumptions of the accident analyses and are based upon maintaining at least one redundant set of onsite A.C. and D.C.
power sources and associated distribution systems OPERABLE during accident conditions coincident with an assumed loss of offsite power and single failure Ethe-o,ther te A.C. source.
Ann IAuerr s -- ACTION requirements are specified for performance of the chemi-cal cleaning required by Surveillance Requirement 4.8.1.1.2.f.1. The motor- R123 driven fuel pumps for the diesel generator set with the tanks being cleaned will be temporarily connected to the underground storage tanks for the other
) diesel generator set with the same train designation. An additional fuel-oil inventory of approximately 68,000 gallons will be available in one of the yard storage tanks prior to the start of the chemical cleaning of any underground storage tank. Within practical limits, the chemical cleanir.g of an underground storage tank will be performed during a refueling or other scheduled outage for the associated unit.
The OPERABILITY of the minimum specified A.C. and D.C. power sources and associated distribution systems during shutdown and refueling ensures that 1) the facility can be maintained in the shutdown or refueling condition for extended time periods and 2) sufficient instrumentation and control capability is available for monitoring and maintaining the unit status.
The Surveillance Requirements for demonstrating the OPERABILITY of the diesel generators are in accordance with the recommendations of Regulatory Guides 1.9 " Selection of Diesel Generator Set Capacity for Standby Power Sup-plies," March 10, 1971, and 1.108 " Periodic Testing of Diesel Generator Units Used as Onsite Electric Power Systems at Nuclear Power Plants," Revision 1, August 1977, and 1.137 " Fuel-0il Systems for Standby Diesel Generators," Revi- R164 sion 1, October 1979. The surveillance requirements for the diesel generator load-run test and the 24-hour endurance and margin test are in accordance with Regulatory Guide 1.9, Revision 3, July 1993, " Selection, Design, Qualification, and Testing of Emergency Diesel Generator Units Used as Class lE Onsite Elec-tric Power Systems at Nuclear Power Plants." During the diesel generator endurance and margin surveillance test, momentary transients outside the kw and
) kvar load ranges do not invalidate the test results. Similarly, during the diesel generator load-run test, momentary transients outside the kw load range do not invalidate the test results.
SEQUDYAH - UNIT 2 B 3/4 8-1 Amendment No. 123, 164 November 29, 1993
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[ . INSERT B: The footnote for Action b of LCO 3.8.1.1 requires completion of a ,
determination that the OPERABLE diesel generators are not i inoperable due to common cause failure or performance of Surveillance 4.8.1.1.2.a.4 if Action b is entered. The intent is l
.that all diesel generator inoperabilities must be investigated for. !
common cause failures regardless of how long the diesel
- generator inoperability persists. ,
The action to determine that the OPERABLE diesel generators are
.not inoperable due to common cause failure provides an ,
allowance to avoid unnecessary testing of OPERABLE diesel generators. If it can be' determined that the cause of the -
Inoperable diesel generator does not exist on the OPERABLE diesel generators,' Surveillance Requirement 4.8.1.1.2.a.4 does not have to be performed. lf the cause of inoperability exists on other.
diesel generator (s), the other diesel generator (s) would be ,
declared inoperable upon discovery and Action e of LCO 3.8.1.1' would be entered as applicable. Once the common failure is :
repaired, the common cause no longer exists, and the action to determine inoperability due to common cause failure is satisfied. -i If the cause of the initial inoperable' diesel generator cannot be !
confirmed not to exist on the remaining diesel generators, performance of Surveillance 4.8.1.1.2.a.4 suffices to provide assurance of continued OPERABILITY of the other diesel generators.
According to Generic Letter 84-15,24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> is reasonable'to' ,
confirm that the OPERABLE diesel generators are not affected by the same problem as the inoperable diesel generator.
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ENCLOSURE 2- l PROPOSED TECHNICAL SPECIFICATION (TS) CHANGE -
SEQUOYAH NUCLEAR PLANT (SON) UNITS _1 AND 2 !
. DOCKET NOS. 50-327 AND' 50d28 (TVA-SON-TS-94-19) .
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DESCRIPTION AND JUST!FICATION FOR q ELIMINATING UNNECESSARY DIESEL GENERATOR TESTING d
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Descriotion of Chanae
, TVA p'roposes to modify the Sequoyah Nuclear Plant (SON) Units 1 and 2
_ technical specifications (TSs) to revise the actions for TS 3.8.1'.1 and eliminate unnecessary. diesel generator (D/G) starts. The existing Action'a will be. .
revised to cover one inoperable D/G and is relabeled as Action b. This action is footnoted to clarify that D/G inoperabilities require the determination that the ' '
operable _D/Gs are not inoperable due to common cause failure' or perform, Surveillance 4.8.1.1.2.a.4 whenever Action b is entered. The inoperability of one offsite circuit will be covered by the addition of a new Action a. The existing " Actions b through d" will be renumbered "c through e," respectively.
The proposed Action a will no longer require the testing of operable D/Gs, but will retain the verification of the operable offsite circult. The proposed Action b will require the testing of operable D/Gs if the inoperability of the -
affected D/G has the_ potential to be the result of a ' common cause failure. I Verification of the offsite circuits for an inoperable D/G has not been changed.
The bases Section 3/4.8.1 and 3/4.8.2 has been revised to add guidance on the use of common cause failure determinations to avoid unnecessary D/G testing in accordance with Surveillance 4.8.1.1.2.a.4. .
Reason for Chanae '
The existing TSs require the verification of D/G operability within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> whenever one of the required alternating-current (ac) electrical power sources is inoperable. This verification is achieved by starting each operable D/G within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of the identified inoperability. During D/G outages that require extensive preventive maintenance and inspection activities or modification activities, the remaining D/Gs could be started unnecessarily to prove their operability. Generic Letter 84-15 recommended that licensees take actions that would reduce unnecessary starts of the D/Gs because of the degradation that results. The proposed change will further reduce the number of starts ,
required of the SON D/Gs by only starting the operable D/Gs when a common- ]
cause failure could exist. The new Action a will no longer require the starting '
of D/Gs when an offsite circuit is inoperable because an offsite circuit failure would not be a common cause failure for a D/G.
Justification for Chances i The proposed changes are consistent with the bases associated with the standard TS (NUREG 1431) actions for an inoperable ac electrical power source. The testing of operable D/Gs when there is no possibility of a common cause failure of the inoperable D/G does not provide a benefit and increases the degradation of the D/Gs unnecessarily. This change will still require the D/Gs to be verified to be operable whenever a failure could be the result of a
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common cause failure that may exist on the other D/Gs. The added footnote clarifies that the common cause determination must be completed regardless of how long the D/G inoperability persists or the performance of Surveillance 4.8.1.1.2.a.4 shall be completed to verify D/G operability. The added bases discussions provide clear guidance on the use of common cause failure determinations to eliminate unnecessary D/G testing and defines when testing is required to verify D/G operability. D/G testing for an inoperable offsite circuit can be removed because failures of these circuits would not be common to the D/Gs. Therefore, the reduction of D/G starts, as proposed by this change request, will improve the reliability of the D/Gs and still maintain reasonable verification of ac electrical power source operability.
Environmental Imoact Evaluatiorl The proposed change does not involve an unreviewed environmental question because operation of SON 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 appraisals, or decisions of the Atomic Safety and Licensing Board.
- 2. Result in a significant change in effluents or power levels.
- 3. Result in matters not previously reviewed in the licensing basis for SON that may have a significant environmental impact.
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ENCLOSURE 3 '
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' PROPOSED TECHNICAL SPECIFICATION CHANGE l
SEQUOYAH NUCLEAR PLANT (SON) UNITS.1 AND 2 ,
I DOCKET NOS. 50-327 AND 50-328 :l (TVA-SON-TS-94-19)
DETERMINATION OF NO SIGNIFICANT HAZARDS CONSIDERATION i
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lSignificant Hazards Evaluation p
TVA has evaluated the proposed technical specification.(TS) change and has L . ;
L : determined that it does not represent a significant hazards consideration based '
m on criteria established in 10 CFR 50.92(c). , Operation'of Sequoyah Nuclear;
. Plant (SON) in accordance with the proposed amendment will not:'
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.1. Involve.a significant increase in.the probability or consequences of an accident previously evaluated.
The proposed revisions do not alter the plant-features or operating practices. This revision will r' educe unnecessary s' tarts of the diesel generators (D/Gs) when a common cause failure is not involved or for an. . , :
Inoperable offsite circuit. This change will not affect the accident ~
. mitigation capabilities'of the D/Gs, but should improve the reliability by. >
reducing the wear and tear associated with starting the D/Gs. The D/Gs are not the source of a postulated accident and because.this _ change does not alter plant functions or operating practices the probability of an -
accident is not increased. The D/G's operability will continue to be' verified for conditions that indicate a potential common-cause failure to ensure 4 accident' mitigation capabilities are not affected. Thereforer this revision ;
will continue to provide actions that will support alternating-current (ac) electrical power source safety functions 'without unnecessary _ degradation of the D/Gs and will not increase the consequences of an accident.
- 2. Create the possibility of a new or different kind of accident from any :
previously analyzed.
The D/Gs are not the source of accidents and the proposed revision will '
not alter plant functions or actions by'more appropriately limiting the conditions when a D/G must be verified operable. Therefore, the possibility of a new or different accident is not created, r
3.. Involve a significant reduction in a margin of safety. -
This revision does not' alter plant functions that provide the margin of safety. The reduction of D/G testing will only be allowed for situations where the. operable D/Gs are not affected by the conditions resulting in'the' ;
ac power source inoperability. This reduced testing should improve D/G reliability for accident mitigation functions and further ensure the margin of ,
safety provided by the D/Gs. Therefore, the margin of safety is not reduced by the proposed revision to limit unnecessary D/G starts.
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