ML20212Q238
| ML20212Q238 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 08/27/1986 |
| From: | COMMONWEALTH EDISON CO. |
| To: | |
| Shared Package | |
| ML20212Q236 | List: |
| References | |
| 2036K, NUDOCS 8609040115 | |
| Download: ML20212Q238 (6) | |
Text
o ELECTRfCAL POWER SYSTEMS f
3/4.8.2 D.C. SOURCES OPERATING LIMITING CONDITION FOR OPERATION 3.8.2.lb As a minimum the following D.C. electrical sources shall be OPERABLE:
l J
dele.+ e 125-Volt D.C. Bus 111 fed from Battery 111 for Unit 1 (Bus 211 fed a.
from Battery 211 for Unit 2), and its associated full capacity charger, and b.
125-Volt D.C. Bus 112 fed from Battery 112 for Unit 1 (Bus 212 fed from Battery 212 for Unit 2), and its associated, full capacity charger.
APPLICABILITY:
MODES 1, 2, 3, and 4.
ACTION:
a.
With one of the required battery banks and/or chargers inoperable, restore the inoperable battery bank and/or battery bus 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 />, b.
With the normal full capacity charger inoperable:
- 1) restore the affected battery and/or battery bus to operable status with the opposite units full capacity charger 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 />, and 2) restore the normal full capacity charger 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 />.
C.
IN SER.T SURVEILLANCE REOUIREMENTS 4.8.2.1.1 Each D.C'. bus shall be determined OPERABLE and energized from its battery at least once per 7 days by verifying correct breaker alignment.
4.8.2.1.2 Each 125-volt battery bank and its associated charger shall be demonstrated OPERABLE:
a.
At least once per 7 days by verifying that:
1)
The parameters in Table 4.8-2 meet the Category A limits, and 2)
The total -battery terminal voltage is greater than or equal to 126 volts on float charge.
QhisspecificationisonlyapplicablepriortoUnit2operatior in MODE D de,ltle A BYRON - UNITS 1 & 2 3/4 8-10 i
9609040115 860827 DR ADOCK 05000424 PDR w.
INSElt?
l c.
Use of the D.C. crosstie breakers between opposite unit D.C. buses (bus 111 and 211, or bus 112 and 212) shall be limited to the following:
(1) With a normal full capacity charger inoperable, comply with action statement (b) above.
(2) With a D.C. bus inoperable or not energized on a shutdown unit (Mode 5 or 6), the affected D.C. bus may be energized from the operating unit (Mode 1, 2, 3 or 4) opposite D.C. bus via the crosstie breakers after limiting the D.C. loads on the affected D.C. bus; operation may then continue 1"or up to 7 days or open the crosstie breakers.
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ELECTRICAL POWER SYSTEMS D.C. SOURCES SHUTDOWN LIMITING CONDITION FOR OPERATION 3.8.2.2 As a minimum, one 125-volt D.C. bus fed from its battery and its associated full-capacity charger shall be OPERABLE. *
}
APPLICABILITY:
MODES 5 and 6.
i ACTION:
With the required battery bank and/or full-capacity charger inoperable, imme-4 diately suspend all operations involving CORE ALTERATIONS, pos.itive reactivity changes or movement of irradiated fuel;. initiate corrective action to restore the required battery bank and full-capacity charger to OPERABLE status as soon as possible, and within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />, depressurize and vent the Reactor Coolant System through at least a 2 square inch vent.
4 A
SURVEILLANCE REQUIREMENTS 4.8.2.2 The above required 125-volt D.C. bus fed from its battery and its associated charger shall be demonstrated OPERABLE per Specifications 4.8.2.1.1 and 4.8.2.1.2.
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BYRON - UNITS 1 & 2 3/4 8-13
._... _. _, ~_._._
ELECTRICAL POWER SYSTEMS SURVEILLANCE REQUIREMENTS (Continued) 4.8.2.1.3 At least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, when in specification 3.8.2.1.c.(2), verify the total crosstie loading will not exceed 63 amps.
BYRON UNITS 1 & 2 3/4 8-lla 2036K
ATTACIGENT B SUP9tARY OF PROPOSED CHANGES This proposed amendment modifies the D.C. system technical specifications to address operation of the D.C. crosstie between units for the following two situations:
With both units operating and one battery charger fails, the D.C.
crosstie may be used for up to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to maintain the D.C. bus in an operable status while the battery charger is being repaired.
With one unit operating and the other unit shutdown with a battery and its associated battery charger out of service, the D.C.
crosstie may be used for up to 7 days to maintain the D.C. bus in an operable status.
Calculations have been performed to justify use of the D.C. crosstie for the two situations discussed above.
For the first situation, each battery will be connected to its bus. One battery charger will serve both buses. As a result, use of the D.C. crosstie will not exceed the design parameters of the D.C. system.
For the second situation, the battery charger and battery of the operable D.C. bus will supply both buses.
In this case, the D.C. crosstie load will be limited to 63 amps (per proposed surveillance requirement 4.8.2.1.3) since a battery does not have sufficient capacity to supply the design load cycle for both D.C. buses.
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'l ATTACHMpMT C l
EVALUATION OF SIGNIFICANT HAZARDS CONSIDERATIONS Comenonwealth Edison has evaluated this proposed amendment and determined that it involves no significant hazards considerations.
According to 10 CFR 50.92(c), a proposed amendment to an operating license involves no significant hazards considerations if operation of the facility in accordance with the proposed amendment would not:
(1) Involve a significant increase in the probability or consequences of an accident previously evaluated; or (2) Create the possibility of a new or different kind of accident from any accident previously evaluated; or (3) Involve a significant reduction in a margia of narety.
This proposed amendment controls the use of sie D.C. crosstie between opposite unit D.C. buses. Accidents previously evaluated assume a certain load profile on a D.C. bus. The D.C. bus loading, when using the crosstie, will be restricted so the capacity of the operating unit's battery will not be exceeded in the event of a single failure and simultaneous accident and loss of offsite power conditions. A single failure and simultaneous accident and loss of offsite power are the conditions assumed for a D.C. bus in previously evaluated accidents. As a result, the probability or consequences of accidents previously evaluated are not changed by this proposed amendment.
The only new or different kind of accident which could be created by this proposed amendment would involve an interaction between the two D.C.
buses which are crosstied. However, a breaker exists on either side of the crosstie which would isolate any potential short circuit from either unit.
These breakers are coordinated'with the D.C. bus main breaker to assure the crosstie will isolate from the affected D.C. bus before the battery would be isolated. All of these breakers are class 18.
For these reasons, a new or different kind of accident will not be created from this proposed amendment.
This proposed amendment will allow use of some margin in the capacity of the batteries which was allocated for future D.C. loads.
However, no design margin in the batteries (i.e., aging or temperature correction factors) has been affected by this proposed amendment.
Accordingly, no margin of safety has been reduced.
Based on the preceeding assessment, commonwealth Edison believes this proposed amendment involves no significant hazards considerations.
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