ML20086C258
| ML20086C258 | |
| Person / Time | |
|---|---|
| Site: | Mcguire |
| Issue date: | 06/29/1995 |
| From: | DUKE POWER CO. |
| To: | |
| Shared Package | |
| ML20086C257 | List: |
| References | |
| NUDOCS 9507060389 | |
| Download: ML20086C258 (6) | |
Text
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f PLANT SYSTEMS AUX LIARY FEEDWATER SYSTEM i
LIMITING CONDITION FOR OPERATION 3.7.1.2 At least three independent steam generator auxiliary feedwater pumps and associated flow paths shall be OPERABLE with:
1 a.
Two motor-driven auxiliary feedwater pumps, each capable of being powered from separate emergency busses, and l
l b.
One steam turbine-driven auxiliary feedwater pw.p capable of being powered from an OPERABLE steam supply system.*
)
1 APPLICABILITY: MODES 1, 2, and 3.
l l
ACTION:
a.
With one auxiliary feedwater pump inoperable, restore the required auxiliary feedwater pumps 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 HOT SHUTDOWN within the following 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.
b.
With two auxiliar feedwater pumps inoperable, be in at least HOT STANDBY within hours and in HOT SHUTDOWN within the following 6
~'
\\ hours.
c.
With three auxiliary feedwater pumps inoperable, immediately initiate corrective action to restore at least one auxiliary feedwater pump to operable status as soon as possible.
SURVEILLANCE RE0VIREMENTS 4.7.1.2 Each auxiliary feedwater pump shall be demonstrated OPERABLE:
1 a.
At least once per 31 days by:
2 1)
Verifying that each non-automatic valve in the flow 3 path that is not locked, sealed, or otherwise secured in position, is in its correct position; 2)
Verifying that each automatic valve in the flow path is in the fully open position whenever the Auxiliary Feedwater System is placed in automatic control or when above 10% RATED THERMAL POWER; and l
3)
Verifying that the isolation valves in the auxiliary feedwater l
suction line from the upper surge tanks are open with power to the valve operators removed.
- Not applicable with steam pressure less than 900 psig.
McGUIRE - UNITS I and 2 3/4 7-4 Amendment No.151 (Unit 1)
Amendment No. 133 (Unit 2) 9507060389 950629 PDR ADOCK 05000370 P
PDR I
r 2
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/go ao ELECTRICAL' POWER SYSTEMS g
LIMITING CONDITION FOR OPERATION ACTION: (Continued) generator restored to OPERABLE status, follow action statement a; with the offsite circuit restored to OPERABLE status, follow action statement d.
c.
With one diesel generator inoperable in addition to ACTION b. or d.
above, verify that:
1.
All required systems, subsystems, trains, components, and devices that depend on the remaining OPERABLE diesel generator as a source of emergency power are also OPERABLE, and 2.
When in MODE 1, 2, or 3 with a steam pressure greater than 900 psig, the steam-driven auxiliary feedwater pump is OPERABLE.
If these conditions are not satisfied within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> 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 a diesel generator of the above required A.C. electrical power sources inoperabl.e*, demonstrate the OPERABILITY of the A.C. offsite sources by performing Surveillance Requirement 4.8.1.1.la within-T 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> 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 unless the in-operability of the diesel was due to preplanned testing or maintenance, demonstrate the OPERABILITY of the remaining diesel generator by per-forming Surveillance Requirements 4.8.1.1.2a.4) and 4.8.1.1.2a.5) within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or unless the diesel is operating **, restore diesel generators 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 />.
e.
With two of the above required offsite A.C. circuits inoperable, separately demonstrate the OPERABILITY of two diesel generators by performing Surveillance Requirements 4.8.1.1.2a.4) and 4.8.1.1.2a.5) within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />, unless the diesel generators 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 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 only one offsite source restored, follow action statement a.
f.
With two of the above required diesel generators inoperable *, deuon-strate the OPERABILITY of two offsite A.C. circuits by performing Surveillance Requirement 4.8.1.1.la. within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> and at least once
- A diesel generator shall be considered to be inoperable from the time of failure until it satisfies the requirements of Surveillance Requirements
)
4.8.1.1.2a.4) and 4.8.1.1.2a.5).
- This test is required to be completed regardless of when the inoperable diesel generator is restored to OPERABLE status.
The provisions of 4
Specification 3.0.2 are not applicable.
McGUIRE - UNITS 1 and 2 3/4 8-2 Amendment No. 71. (Unit 1)
Amendment No. 52 (Unit 2)
w ELECTRICAL POWER SYSTEMS
'7 LIMITING CONDITION FOR OPERATION
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ACTION: (Continued) per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> thereafter; restore at I ast one of the inoperable diesel generators to OPERABLE stat 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 STAN08Y within the next 6 ours and in COLD.SHUTOOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />. W th one diesel generator restored, follow action statement d.
SURVEILLANCE REQUIREMENTS 4.8.1.1.1 Each of.the above required independent circuits between the offsite transmission network and the onsite Essential Auxiliary-Power 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 transferring (manually and automatically) unit power supply from the
-F normal circuit to the alternate circuit.
4.8.1.1.2 Each diesel generator shall be demonstrated OPERABLE:
a.
In accordance with the frequency specified in Table 4.8-1 on a STAGGERED TEST BASIS, by:
1)
Verifying the fuel level in the day tank, i
4 i
McGUIRE - UNITS 1 and 2 3/4 6-2a Amendment No.71 (Unit 1)
Amendment No.52 (Unit 2) i
F McGuire Unit 2 Safety Evaluation in Support of Continued Power Operation With a Degraded Diesel Introduction The ability of the four McGuire D/Gs to provide emergency power is considered degraded in light of the failure of the turbo-charger associated with Diesel 2A. McGuire has decided to shutdown Unit 1.
It is desirable to continue power operation of Unit 2 in order to preserve the power generating capability of one unit. It is believed that continued operation is more desirable from an overall safety standpoint than a two unit shutdown.
This evaluation presents an analysis of the safety of continued power operation of Unit 2 for a limited period of time with the DGs considered inoperable.
Discussion With the DGs considered inoperable, the accident of concem is a loss of offsite power event. He existing McGuire PRA uses a LOOP frequency of 0.07 events per year. For a one day period, this frequency translates to 1.92E-04 per day. His frequency would be applicable to either unit (Unit I shutdown or Unit 2 at power).
If Unit 1 experiences a LOOP and the DGs are assumed failed, power can be made available by using the shared transformer (S ATA / SATB). It is assumed that the operator action to restore power on Unit I with the heightened awareness of the degraded DG condition and the time available to perform the action would be highly reliable (a value of 0.01 is assumed). For the purpose of this analysis, a value of 0.1 is assumed for the failme of Unit 2 to run back to supply power following a LOOP.
The probability oflosing all powe'r for Unit 1 is (Probability of a One Unit LOOP] x [ Probability of Failure to Cross Connect Power From Unit 2]
+ [ Probability of a 2 Unit LOOP] x [ Probability that Unit 2 Will Fail to Runback
+ Probability to Cross Connect Power from the Unit 2 Generator]
Using numbers in this expmssion gives:
-]
(0.07/yi] x [0.01] + (0.07/yr X 0.17] x [0.1 +0.01]
This gives: 7E-04 + 1.31E-03 = 2.01E-03/y = 5.5E-06per day
\\
i
e r
9:
, ith Unit 2 not operating the following expression applies W
[ Probability of a One Unit LOOP] x [ Probability of Failure to Cross Connect f
Power From Unit 2]
+ [ Probability of a 2 Unit LOOP]
Using numbers in this expression gives:
[0.07/yr] x [0.01] + [0.07/yr X 0.17]
This gives: 7E-04 + 1.19E-02/yr = 1.26E 02/yr = 3.45E-05 per day Thus the probability of using Unit 2 for Unit 1 power is increased with the Unit allowed to operate.
s If Unit 2 is operating, the probability oflosing power on Unit 2 is:
i
[One Unit LOOP] x [ Unit 2 Fails to Run Back] x [ Cross Connect to Unit 1]
i
+ [2 Unit LOOP ] x [ Unit 2 Fails to Run Back]
Using numbers in the above expression g!ves-I 0.07/yr x 0.1 x 0.01 + 0.07/yr x 0.17 x 0.1 = 1.26E-03/yr = 3.45E 06 per day If the Unit is not operating, this becomes:
[One Unit LOOP] x [ Cross Connect to Unit 1]
+ [2 Unit L.OOP ]
Using numbers in the above expression gives:
O.07/yr x 0.01 + 0.07/yr x 0.17 =1.26E-02/yr= 3.45E-05 per day Thus for both units, the probability of losing AC power is reduced with one unit allowed to operate. The difference is 3.45B-05 per day for no units operating vs. 3.45E-06 per day for one unit operating.
This analysis has not taken credit for the recovery of offsite power, the CSF or the potential availability of the emergency diesel generators.
Conclusion m
With th'e degraded diesel generators, continued power operation of McGuire Unit 2 provides an additional source of AC power for the McGuire site and, thereby, reduces the probability of total loss of AC power to either unit. Such a mode of operation is more desirable from an overall safety standpoint. For both units, the probability of losing AC power is reduced with one unit allowed to operate. The difference is 3.45E-05 per day for no units operating vs. 3.45E-06 per day for one unit operating 45 5
TOTAL P.04