Text

Technical Specification Bases, Revisions 44 and 45, B 3.8, Electrical Power Systems
	ML12284A257
Person / Time
Site:	Calvert Cliffs
Issue date:	10/02/2012
From:	; Calvert Cliffs, Constellation Energy Nuclear Group
To:	; Office of Nuclear Reactor Regulation
References
	Download: ML12284A257 (93)
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AC Sources-Operating B 3.8.1 B 3.8 ELECTRICAL POWER SYSTEMS B 3.8.1 AC Sources-Operating

BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-1 Revision 5 BACKGROUND The AC sources to the Class 1E Electrical Power Distribution System consist of the offsite power sources starting at the 4.16 kV engineered safety feature (ESF) buses and the onsite diesel generators (DGs). As required by Reference 1, General Design Criteria (GDC) 17, the design of the AC electrical power system has sufficient independence and

redundancy to ensure a source to the ESFs assuming a single

failure.

The Class 1E AC Distribution System is divided into two

redundant load groups so that the loss of one group does not

prevent the minimum safety functions from being performed.

Each load group has connections to two offsite sources and

one Class 1E DG at its 4.16 kV 1E bus.

Offsite power is supplied to the 500 kV Switchyard from the

transmission network by three 500 kV transmission lines.

Two electrically and physically separated circuits supply

electric power from the 500 kV Switchyard to two 13 kV buses

and then to the two 4.16 kV ESF buses. A third 69 kV/

13.8 kV offsite power source that may be manually connected

to either 13 kV bus is available from the Southern Maryland

Electric Cooperative (SMECO). When appropriate, the

Engineered Safety Feature Actuation System (ESFAS) loss of

coolant incident and shutdown sequencer for the 4.16 kV bus

will sequence loads on the bus after the 69 kV/13.8 kV SMECO

line has been manually placed in service. The SMECO offsite

power source will not be used to carry loads for an

operating unit. A detailed description of the offsite power

network and the circuits to the Class 1E ESF buses, is found

in Reference 2, Chapter 8.

The required offsite power circuits are the two 13 kV buses (Nos. 11 and 21) which can be powered by: a. Two 500 kV lines, two 500 kV buses each of which have connections to a 500 kV line that does not pass through the other 500 kV bus and both P-13000

(500 kV/14 kV) transformers; or AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-2 Revision 12

b. One 500 kV line, one 500 kV bus, and one associated P-13000 (500 kV/

13.8 kV) transformer, and the 69 kV/

13.8 kV SMECO line. When the SMECO line is credited as one of the qualified offsite circuits, the

disconnect from the SMECO line to Warehouse No. 1 must

be open.

In addition, each offsite circuit includes the cabling to

and from a 13.8/13.8 kV voltage regulator , 13.8/4.16 kV unit service transformer , and one of the two breakers to one 4.16 kV ESF bus. Transfer capability between the two

required offsite circuits is by manual means only. The

required circuit breaker to each 4.16 kV ESF bus must be

from different 13.8/4.16 kV unit service transformers for the two required offsite circuits. Thus, each unit is able

to align one 4.16 kV bus to one required offsite circuit, and the other 4.16 kV bus to the other required offsite

circuit.

In some cases, inoperable components in the electrical

circuit place both units in Conditions. Examples of these

are 13.8 kV bus Nos. 11 or 21, two 500 kV transmission

lines, one P-13000 service transformer, or one 500 kV bus.

In other cases, inoperable components only place one unit in

a Condition, such as an inoperable U-4000 and/or 13.8 kV

regulator that feeds a required 4.16 kV bus.

The onsite standby power source to each 4.16 kV ESF bus is a dedicated DG. A DG starts automatically on an safety

injection actuation signal or on a 4.16 kV degraded or

undervoltage signal. If both 4.16 kV offsite source

breakers are open, the DG, after reaching rated voltage and

frequency, will automatically close onto the 4.16 kV bus.

In the event of a loss of offsite power to a 4.16 kV 1E bus, if required, the ESF electrical loads will be automatically sequenced onto the DG in sufficient time to provide for safe

shutdown for an anticipated operational occurrence (AOO) and

to ensure that the containment integrity and other vital

functions are maintained in the event of a design bases

accident.

AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-3 Revision 2 Ratings for the No. 1A DG satisfies the requirements of Reference 3 and ratings for the Nos. 1B, 2A, and 2B DG s satisfy the requirements of Reference 4

. The continuous service rating for the No. 1A DG is 5400 kW and for the Nos. 1B, 2A, and 2B DGs are 3000 kW.

APPLICABLE The initial conditions of Design Basis Accident (DBA) and SAFETY ANALYSES transient analyses in Reference 1, Chapters 6 and 14, assume ESF systems are OPERABLE. The AC electrical power sources

are designed to provide sufficient capacity, capability, redundancy, and reliability to ensure the availability of

necessary power to ESF systems so that the fuel, RCS , and containment design limits are not exceeded. These limits

are discussed in more detail in the Bases for Section s 3.2 , 3.4 , and 3.6.

The OPERABILITY of the AC electrical power sources is

consistent with the initial assumptions of the accident

analyses and is based upon meeting the design basis of the

unit. This results in maintaining at least one train of the

onsite or offsite AC sources OPERABLE

, during accident conditions in the event of:

a. An assumed loss of all offsite power; and

b. A single failure.

The AC sources satisfy 10 CFR 50.36(c)(2)(ii), Criterion 3.

LCO Two qualified circuits between the offsite transmission

network and the onsite Class 1E Electrical Power

Distribution System and separate and independent DGs for

each train ensure availability of the required power to shut

down the reactor and maintain it in a safe shutdown

condition after an AOO or a postulated DBA.

Qualified offsite circuits are those that are described in the Updated Final Safety Analysis Report (UFSAR) and are part of the licensing basis for the unit.

Each offsite circuit must be capable of maintaining rated

frequency and voltage and accepting required loads during an

accident, while connected to the ESF buses. Loads are

immediately connected to the ESF buses when the buses are AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-4 Revision 10 powered from the 500 kV offsite circuits and, when powered from the 69/13.8 kV SMECO offsite circuit after being

manually connected, the loads are sequenced onto the ESF bus

utilizing the same sequencer used to sequence the loads onto

the DG. The SMECO offsite circuit will not be used to carry

loads for an operating unit.

The Limiting Condition for Operation (LCO) requires

operability of two out of three qualified circuits between

the transmission network and the onsite Class 1E AC

Electrical Power Distribution System circuits. These

circuits consist of two 500 kV circuits via 500 kV/14 kV and

13.8 kV/4.16 kV transformers and the 69 kV SMECO dedicated

source (described in Reference 5) via 69 kV/13.8 kV and

13.8 kV/4.16 kV transformers. In addition, each offsite

circuit includes one of the two breakers to one 4.16 kV ESF

bus. The required circuit breaker to each 4.16 kV ESF bus

must be from different 13.8/4.16 unit service transformers

for the two required offsite circuits. Thus, each unit is

able to align one 4.16 kV bus to one required offsite

circuit, and the other 4.16 kV bus to the other required

offsite circuit.

Each DG must be capable of starting, accelerating to rated speed and voltage, and connecting to its respective ESF bus

on detection of bus undervoltage. This will be accomplished

within 10 seconds. Each DG must also be capable of

accepting required loads within the assumed loading sequence

intervals, and continue to operate until offsite power can

be restored to the ESF buses.

These capabilities are required to be met from a variety of initial conditions such

as DG in standby with the engine hot and DG in standby with

the engine at ambient conditions. Additional DG

capabilities must be demonstrated to meet required Surveillances, e.g., capability of the DG to reject a load 500 hp without tripping.

Proper sequencing of loads, including shedding of non-essential loads, is a required function for DG OPERABILITY

in MODEs 1, 2, and 3.

AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-5 Revision 26 The AC sources in one train must be separate and independent (to the extent possible) of the AC sources in the other

train. For the DGs, separation and independence are

complete.

The Control Room Emergency Ventilation System (CREVS) and Control Room Emergency Temperature System (CRETS) are shared systems with one train of each system connected to an onsite

Class 1E AC electrical power distribution subsystem from

each unit. Limiting Condition for Operation 3.8.1.c

requires one qualified circuit between the offsite

transmission network and the other unit's onsite Class 1E AC

electrical power distribution subsystems needed to supply

power to the CREVS and CRETS to be OPERABLE and one DG from

the other unit capable of supplying power to the CREVS and

CRETS to be OPERABLE. The qualified circuit in LCO 3.8.1.c

must be separate and independent (to the extent possible) of

the qualified circuit which provides power to the other

train of the CREVS and CRETS. These requirements, in

conjunction with the requirements for the unit AC electrical

power sources in LCO 3.8.1.a and LCO 3.8.1.b, ensure that power is available to two trains of the CREVS and CRETS.

APPLICABILITY The AC sources are required to be OPERABLE in MODEs 1, 2, 3, and 4 to ensure that:

a. Acceptable fuel design limits and reactor coolant pressure boundary limits, are not exceeded as a result

of AOOs or abnormal transients; and b. Adequate core cooling is provided and Containment OPERABILITY and other vital functions, are maintained in the event of a postulated DBA.

The AC power requirements for MODEs 5 and 6 are covered in LCO 3.8.2.

ACTIONS A Note prohibits the application of LCO 3.0.4.b to an inoperable DG. There is an increased risk associated with entering a MODE or other specified condition in the Applicability with an inoperable DG and the provisions of LCO 3.0.4.b, which allow entry into a MODE or other specified condition in the Applicability with the LCO not met after performance of a risk assessment addressing AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-6 Revision 26 inoperable systems and components, should not be applied in this circumstance.

A.1 To ensure a highly reliable power source remains with the

one required LCO 3.8.1.a offsite circuit inoperable, it is necessary to verify the OPERABILITY of the remaining required offsite circuits on a more frequent basis. Since

the Required Action only specifies "perform," a failure of

Surveillance Requirement (SR) 3.8.1.1 or SR 3.8.1.2

acceptance criteria does not result in a Required Action not

met. However, if a second required circuit fails SR 3.8.1.1

or SR 3.8.1.2, the second offsite circuit is inoperable, and

Condition D and/or G, as applicable, for the two offsite

circuits inoperable, is entered.

A.2 Required Action A.2, which only applies if the train cannot

be powered from an offsite source, is intended to provide

assurance that an event coincident with a single failure of

the associated DG will not result in a complete loss of

safety function of critical redundant required features.

These features are powered from the redundant AC electrical

power train(s). Single train systems may not be included.

The Completion Time for Required Action A.2 is intended to allow the operator time to evaluate and repair any

discovered inoperabilities. This Completion Time also

allows for an exception to the normal "time zero" for

beginning the allowed outage time "clock." In this Required

Action, the Completion Time only begins on discovery that

both: a. The train has no offsite power supplying its loads; and b. A required feature on another train is inoperable.

If at any time during the existence of Condition A (one required LCO 3.8.1.a offsite circuit inoperable) a redundant

required feature subsequently becomes inoperable, this

Completion Time begins to be tracked.

The Completion Time must be started if it is discovered that there is no offsite power to one train of the onsite AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-7 Revision 26 Class 1E Electrical Power Distribution System coincident with one or more inoperable required support or supported

features (or both) that are associated with the other train

that has offsite power. Twenty-four hours is acceptable

because it minimizes risk while allowing time for

restoration before subjecting the unit to transients associated with shutdown.

The remaining OPERABLE offsite circuits and DGs are adequate

to supply electrical power to Train A and Train B of the

onsite Class 1E Distribution System. The 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months Completion

Time takes into account the component OPERABILITY of the

redundant counterpart to the inoperable required feature.

Additionally, the 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months Completion Time takes into account

the capacity and capability of the remaining AC sources, a

reasonable time for repairs, and the low probability of a

DBA occurring during this period.

A.3 Consistent with Reference 6, operation may continue in

Condition A for a period that should not exceed 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months .

With one offsite circuit inoperable, the reliability of the

offsite system is degraded, and the potential for a loss of

offsite power is increased, with attendant potential for a

challenge to the unit safety systems. In this Condition, however, the remaining OPERABLE offsite circuit and DGs are

adequate to supply electrical power to the onsite Class 1E

Distribution System.

The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months Completion Time takes into account the capacity and capability of the remaining AC sources, a reasonable

time for repairs, and the low probability of a DBA occurring

during this period.

The second Completion Time for Required Action A.3 establishes a limit on the maximum time allowed for any combination of required AC power sources to be inoperable

during any single contiguous occurrence of failing to meet

LCO 3.8.1.a or LCO 3.8.1.b. If Condition A is entered

while, for instance, an LCO 3.8.1.b DG is inoperable, and

that DG is subsequently returned OPERABLE, the LCO may

already have been not met for up to 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . This could

lead to a total of 17 days, since initial failure to meet AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-8 Revision 26 LCO 3.8.1.a or LCO 3.8.1.b, to restore the offsite circuit.

At this time, a LCO 3.8.1.b DG could again become

inoperable, the circuit restored OPERABLE, and an additional

72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months (for a total of 20 days) allowed prior to complete

restoration of LCOs 3.8.1.a and 3.8.1.b. The 17 day

Completion Time provides a limit on the time allowed in a specified condition after discovery of failure to meet LCO 3.8.1.a or LCO 3.8.1.b. This limit is considered

reasonable for situations in which Conditions A and B are

entered concurrently. The "AND" connector between the 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months and 17 day Completion Time means that both

Completion Times apply simultaneously, and the more

restrictive Completion Time must be met.

As in Required Action A.2, the Completion Time allows for an

exception to the normal "time zero" for beginning the

allowed outage time "clock." This will result in

establishing the "time zero" at the time that LCO 3.8.1.a or

LCO 3.8.1.b was initially not met, instead of at the time

Condition A was entered.

B.1 The 14 day Completion Time for Required Action B.5 is based

on the OPERABILITY of both opposite-unit DGs and the

availability of the 0C DG. The 0C DG is available to power

the inoperable DG bus loads in the event of a station

blackout or loss-of-offsite power. It is required to

administratively verify both opposite-unit DGs OPERABLE and

the 0C DG available within one hour and to continue this

action once per 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months thereafter until restoration of the

required DG is accomplished. This verification provides

assurance that both opposite-unit DGs and the 0C DG are

capable of supplying the onsite Class 1E AC Electrical Power

Distribution System.

B.2 To ensure a highly reliable power source remains with an

inoperable LCO 3.8.1.b DG, it is necessary to verify the

availability of the offsite circuits on a more frequent

basis. Since the Required Action only specifies "perform,"

a failure of SR 3.8.1.1 or SR 3.8.1.2 acceptance criteria

does not result in a Required Action being not met.

AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-9 Revision 26 However, if a circuit fails to pass SR 3.8.1.1 or SR 3.8.1.2, it is inoperable. Upon offsite circuit

inoperability, additional Conditions and Required Actions

must then be entered.

B.3 Required Action B.3 is intended to provide assurance that a loss of offsite power, during the period that a LCO 3.8.1.b

DG is inoperable, does not result in a complete loss of

safety function of critical systems. These features are

designed with redundant safety-related trains. Single train

systems are not included. Redundant required feature

failures consist of inoperable features with a train, redundant to the train that has an inoperable LCO 3.8.1.b

DG.

The Completion Time for Required Action B.3 is intended to allow the operator time to evaluate and repair any

discovered inoperabilities. This Completion Time also

allows for an exception to the normal "time zero" for

beginning the allowed outage time "clock." In this Required

Action, the Completion Time only begins on discovery that

both: a. An inoperable LCO 3.8.1.b DG exists; and b. A required feature on another train is inoperable.

If at any time during the existence of this Condition (one LCO 3.8.1.b DG inoperable) a required feature subsequently

becomes inoperable, this Completion Time begins to be

tracked.

Discovering one required LCO 3.8.1.b DG inoperable coincident with one or more inoperable required support or

supported features (or both) that are associated with the OPERABLE DGs, results in starting the Completion Time for the Required Action. Four hours from the discovery of these

events existing concurrently, is acceptable because it

minimizes risk while allowing time for restoration before

subjecting the unit to transients associated with shutdown.

In this Condition, the remaining OPERABLE DGs and offsite circuits are adequate to supply electrical power to the AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-10 Revision 26 onsite Class 1E Distribution System. Thus, on a component basis, single failure protection for the required feature's

function may have been lost; however, function has not been

lost. The four hour Completion Time takes into account the

OPERABILITY of the redundant counterpart to the inoperable

required feature. Additionally, the four hour Completion Time takes into account the capacity and capability of the remaining AC sources, a reasonable time for repairs, and the

low probability of a DBA occurring during this period.

B.4.1 and B.4.2 Required Action B.4.1 provides an allowance to avoid

unnecessary testing of OPERABLE DGs. If it can be

determined that the cause of the inoperable DG does not

exist on the OPERABLE DG(s), SR 3.8.1.3 does not have to be

performed. If the cause of inoperability exists on other

DG(s), the other DG(s) would be declared inoperable upon

discovery and Condition E and/or I of LCO 3.8.1, as

applicable, would be entered. Once the failure is repaired, the common cause failure no longer exists and Required

Action B.4.1 is satisfied. If the cause of the initial

inoperable DG cannot be confirmed not to exist on the

remaining DG(s), performance of SR 3.8.1.3 suffices to

provide assurance of continued OPERABILITY of the DG(s).

In the event the inoperable DG is restored to OPERABLE status prior to completing either B.4.1 or B.4.2, the

corrective action program will continue to evaluate the

common cause possibility. This continued evaluation, however, is no longer under the 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months constraint imposed

while in Condition B.

Consistent with Reference 7, 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months is reasonable to confirm that the OPERABLE DG(s) is not affected by the same problem as the inoperable DG.

These Conditions (B.4.1 and B.4.2) do not address the availability of the 0C DG.

B.5 Operation may continue in Condition B for a period that

should not exceed 14 days.

AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-11 Revision 26 Planned entry into this Required Action requires that a risk assessment be performed in accordance with a configuration

risk management program (Reference 11). This ensures that a

proceduralized probabilistic risk assessment-informed

process is in place that assesses the overall impact of plant maintenance on plant risk prior to entering this Required Action for planned activities.

In Condition B, the remaining OPERABLE DGs, available 0C DG, and offsite circuits are adequate to supply electrical power

to the onsite Class 1E Distribution System. The 14 day

Completion Time takes into account the capacity and

capability of the remaining AC sources, a reasonable time

for repairs, and the low probability of a DBA occurring

during this period.

In addition to utilizing Calvert Cliffs Nuclear Power

Plant's processes for evaluating risk, Reference 11, Calvert

Cliffs will administratively limit DG OOS time to 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months

for elective maintenance unless the following actions are

completed: a. Weather conditions will be evaluated prior to entering the extended DG Completion Time for elective maintenance. An extended DG Completion Time will not

be entered for elective maintenance purposes if

official weather forecasts are predicting severe

conditions (tornado or thunderstorm warnings). b. The condition of the offsite power supply will be evaluated prior to entering the extended DG Completion

Time. c. No elective maintenance will be performed in the switchyard, on the 4 kV Distribution System, or on the

13 kV Distribution System. d. No maintenance or testing that affects the reliability of the train associated with the operable DG on the

affected unit will be scheduled during the extended DG

Completion Time. If any testing or maintenance

activities, which affects the train reliability must be

performed while the extended DG Completion Time is in

effect, a 10 CFR 50.65(a)(4) evaluation will be

performed.

AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-12 Revision 26 e. Elective maintenance will not be performed on the alternate AC power source (0C DG). Personnel will be made aware of the dedication of the alternate AC source

to the affected Unit. f. Planned maintenance will not be performed on the Auxiliary Feedwater System. g. The system dispatcher (System Operations and Maintenance Department) will be contacted prior to

removing the DG from service and after it has been

returned to service. h. The operations crews will be briefed concerning the Unit activities, including compensatory measures

established and the importance of promptly starting and

aligning the alternate AC source (0C DG). i. The on-shift operations crew will discuss and review the appropriate normal and emergency operating

procedures prior to or shortly after assuming the watch

for the first time after having scheduled days off

while the extended DG Completion Time is in effect. j. The condition of the grid will be evaluated prior to entering the extended DG 3.8.1 Condition B Completion

Time for elective maintenance. An extended DG

Completion Time will not be entered to perform elective

maintenance when grid stress conditions are considered

"High" per plant procedures. This will include

conditions such as expected extreme summer temperatures

and/or high demand.

The second Completion Time for Required Action B.5 establishes a limit on the maximum time allowed for any

combination of required AC power sources to be inoperable

during any single contiguous occurrence of failing to meet

LCO 3.8.1.a or LCO 3.8.1.b. If Condition B is entered

while, for instance, an LCO 3.8.1.a offsite circuit is inoperable and that circuit is subsequently returned OPERABLE, the LCO may already have not been met for up to

72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . This could lead to a total of 17 days, since

initial failure to meet LCO 3.8.1.a or LCO 3.8.1.b, to

restore the DG. At this time, a LCO 3.8.1.a offsite circuit

could again become inoperable, the DG restored OPERABLE, and

an additional 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months (for a total of 20 days) allowed AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-13 Revision 26 prior to complete restoration of LCO 3.8.1.a and LCO 3.8.1.b. The 17 day Completion Time provides a limit on

time allowed in a specified condition after discovery of

failure to meet LCO 3.8.1.a or LCO 3.8.1.b. This limit is

considered reasonable for situations in which Conditions A

and B are entered concurrently. The "AND" connector between the 14 day and 17 day Completion Times means that both

Completion Times apply simultaneously, and the more

restrictive Completion Time must be met.

As in Required Action B.3, the Completion Time allows for an

exception to the normal "time zero" for beginning the

allowed time "clock." This will result in establishing the "time zero" at the time that LCO 3.8.1.a or LCO 3.8.1.b was

initially not met, instead of at the time Condition B was

entered. C.1.1 and C.1.2 In Condition C with an opposite-unit DG inoperable and/or

the 0C DG unavailable, the remaining OPERABLE unit-specific

DG and required qualified circuits are adequate to supply

electrical power to the onsite Class 1E Distribution System.

Consistent with Reference 6, operation may continue in

Condition C for a period that should not exceed 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months .

The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months Completion Time takes into account the capacity

and capability of the remaining AC sources, a reasonable

time for repairs, and the low probability of a DBA occurring

during this period.

D.1 Pursuant to LCO 3.0.6, the Distribution System ACTIONS would

not be entered even if all AC sources to it, were inoperable

resulting in de-energization. Therefore, the Required

Actions of Condition D are modified by a Note to indicate that when Condition D is entered with no AC source to any train, the Conditions and Required Actions for LCO 3.8.9, must be immediately entered. This allows Condition D to

provide requirements for the loss of the LCO 3.8.1.c offsite

circuit and DG without regard to whether a train is de-

energized. Limiting Condition for Operation 3.8.9 provides

the appropriate restrictions for a de-energized train.

AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-14 Revision 26 To ensure a highly reliable power source remains with the one required LCO 3.8.1.c offsite circuit inoperable, it is

necessary to verify the OPERABILITY of the remaining

required offsite circuits on a more frequent basis. Since

the Required Action only specifies "perform," a failure of

SR 3.8.1.1 or SR 3.8.1.2 acceptance criteria does not result in a Required Action not met. However, if a second required circuit fails SR 3.8.1.1 or SR 3.8.1.2, the second offsite

circuit is inoperable, and Condition A and/or G, as

applicable, for the two offsite circuits inoperable, is

entered.

D.2 Required Action D.2, which only applies if the train cannot

be powered from an offsite source, is intended to provide

assurance that an event coincident with a single failure of

the associated DG will not result in a complete loss of

safety function for the CREVS or CRETS. The Completion Time

for Required Action D.2 is intended to allow the operator

time to evaluate and repair any discovered inoperabilities.

This Completion Time also allows for an exception to the

normal "time zero" for beginning the allowed outage time "clock." In this Required Action, the Completion Time only

begins on discovery that both: a. The train has no offsite power supplying its loads; and b. A train of CREVS or CRETS on the other train is inoperable.

If at any time during the existence of Condition D (one required LCO 3.8.1.c offsite circuit inoperable) a train of

CREVS or CRETS becomes inoperable, this Completion Time

begins to be tracked.

Discovering no offsite power to one train of the onsite Class 1E Electrical Power Distribution System coincident

with one train of CREVS or CRETS that is associated with the

other train that has offsite power, results in starting the

Completion Times for the Required Action. Twenty-four hours

is acceptable because it minimizes risk while allowing time

for restoration before subjecting the unit to transients

associated with shutdown.

AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-15 Revision 26 The remaining OPERABLE offsite circuits and DGs are adequate to supply electrical power to Train A and Train B of the

onsite Class 1E Distribution System. The 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months Completion

Time takes into account the component OPERABILITY of the

redundant counterpart to the inoperable CREVS or CRETS.

Additionally, the 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months Completion Time takes into account the capacity and capability of the remaining AC sources, a reasonable time for repairs, and the low probability of a

DBA occurring during this period.

D.3 Consistent with the time provided in ACTION A, operation may

continue in Condition D for a period that should not exceed

72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . With one required LCO 3.8.1.c offsite circuit

inoperable, the reliability of the offsite system is

degraded, and the potential for a loss of offsite power is

increased, with attendant potential for a challenge to the

unit safety systems. In this Condition, however, the

remaining OPERABLE offsite circuits and DGs are adequate to

supply electrical power to the onsite Class 1E Distribution

System.

If the LCO 3.8.1.c required offsite circuit cannot be restored to OPERABLE status within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months , the CREVS and

CRETS associated with the offsite circuit must be declared

inoperable. The ACTIONS associated with the CREVS and CRETS

will ensure the appropriate actions are taken. The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months

Completion Time takes into account the capacity and

capability of the remaining AC sources, a reasonable time

for repairs, and the low probability of a DBA occurring

during this period.

E.1 The 14 day Completion Time for Required Action E.5 is based on the OPERABILITY of the other three safety-related DGs and the availability of the 0C DG. The 0C DG is available to

power the inoperable DG bus loads in the event of a station

blackout or loss-of-offsite power. It is required to

administratively verify the three safety-related DGs

OPERABLE and the 0C DG available within one hour and to

continue this action once per 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months thereafter until

restoration of the required DG is accomplished. This AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-16 Revision 26 verification provides assurance that the three safety-related DGs and the 0C DG are capable of supplying the

onsite Class 1E AC Electrical Power Distribution System.

E.2 Pursuant to LCO 3.0.6, the Distribution System ACTIONS would not be entered even if all AC sources to it, were inoperable resulting in de-energization. Therefore, the Required

Actions of Condition E are modified by a Note to indicate

that when Condition E is entered with no AC source to any

train, the Conditions and Required Actions for LCO 3.8.9

must be immediately entered. This allows Condition E to

provide requirements for the loss of the LCO 3.8.1.c offsite

circuit and DG without regard to whether a train is de-

energized. Limiting Condition for Operation 3.8.9 provides

the appropriate restrictions for a de-energized train.

To ensure a highly reliable power source remains with the one required LCO 3.8.1.c DG inoperable, it is necessary to

verify the availability of the required offsite circuits on

a more frequency basis. Since the Required Action only

specifies "perform," a failure of SR 3.8.1.1 or SR 3.8.1.2

acceptance criteria does not result in a Required Action not

met. However, if a circuit fails to pass SR 3.8.1.1 or

SR 3.8.1.2, it is inoperable. Upon offsite circuit

inoperability additional Conditions and Required Actions

must then be entered.

E.3 Required Action E.3 is intended to provide assurance that a

loss of offsite power, during the period the LCO 3.8.1.c DG

is inoperable, does not result in a complete loss of safety

function for the CREVS or CRETS. The Completion Time is

intended to allow the operator time to evaluate and repair any discovered inoperabilities. This Completion Time also allows for an exception to the normal "time zero" for

beginning the allowed outage time "clock." In this Required

Action, the Completion Time only begins on discovery that

both: a. An inoperable LCO 3.8.1.c DG exists; and

b. A train of CREVS or CRETS on the other train is inoperable.

AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-17 Revision 26 If at any time during the existence of this Condition (the

LCO 3.8.1.c DG inoperable) a train of CREVS or CRETS becomes

inoperable, this Completion Time begins to be tracked.

Discovering the LCO 3.8.1.c DG inoperable coincident with one train of CREVS or CRETS that is associated with the one LCO 3.8.1.b DG results in starting the Completion Time for

the Required Action. Four hours from the discovery of these

events existing concurrently, is acceptable because it

minimizes risk while allowing time for restoration before

subjecting the unit to transients associated with shutdown.

In this Condition, the remaining OPERABLE DGs and offsite

circuits are adequate to supply electrical power to the

onsite Class 1E Distribution System. Thus, on a component

basis, single failure protection for the CREVS or CRETS may

have been lost; however, function has not been lost. The

four hour Completion Time also takes into account the

capacity and capability of the remaining CREVS and CRETS

train, a reasonable time for repairs, and the low

probability of a DBA occurring during this period.

E.4.1 and E.4.2 Required Action E.4.1 provides an allowance to avoid

unnecessary testing of OPERABLE DGs. If it can be

determined that the cause of the inoperable DG does not

exist on the OPERABLE DG(s), SR 3.8.1.3 does not have to be

performed. If the cause of inoperability exists on other

DG(s), the other DG(s) would be declared inoperable upon

discovery and Condition B and/or I of LCO 3.8.1, as

applicable, would be entered. Once the failure is repaired, the common cause failure no longer exists and Required

Action E.4.1 is satisfied. If the cause of the initial inoperable DG cannot be confirmed not to exist on the remaining DG(s), performance of SR 3.8.1.3 suffices to

provide assurance of continued OPERABILITY of the DG(s).

In the event the inoperable DG is restored to OPERABLE status prior to completing either E.4.1 or E.4.2, the

corrective action program will continue to evaluate the

common cause possibility. This continued evaluation, AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-18 Revision 26 however, is no longer under the 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months constraint imposed while in Condition E.

Consistent with Reference 6, 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months is reasonable to

confirm that the OPERABLE DG(s) is not affected by the same

problem as the inoperable DG.

These Conditions (E.4.1 and E.4.2) do not address the

availability of the 0C DG.

E.5 Consistent with the time provided in ACTION B, operation may

continue in Condition E for a period that should not exceed

14 days. In Condition E, the remaining OPERABLE DGs, available 0C DG, and offsite power circuits are adequate to

supply electrical power to the Class 1E Distribution System.

If the LCO 3.8.1.c DG cannot be restored to OPERABLE status within 14 days the CREVS and CRETS associated with this DG

must be declared inoperable. The Actions associated with

the CREVS and CRETS will ensure the appropriate Actions are

taken.

The 14 day Completion Time takes into account the capacity and capability of the remaining AC sources, a reasonable

time for repairs, and the low probability of a DBA occurring

during this period.

F.1.1 and F.1.2 In Condition F, with an additional safety-related DG

inoperable or the 0C DG unavailable, the remaining OPERABLE

DG and required qualified circuits are adequate to supply

electrical power to the onsite Class 1E Distribution System.

Consistent with Reference 6, operation may continue in Condition F for a period that should not exceed 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months .

The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months Completion Time takes into account the capacity

and capability of the remaining AC sources, a reasonable

time for repairs, and the low probability of a DBA occurring

during this period.

AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-19 Revision 26 F.1.3 If the LCO 3.8.1.c DG cannot be restored to OPERABLE status within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months the CREVS and CRETS associated with this DG

must be declared inoperable. The Required Actions

associated with the CREVS and CRETS will ensure that the

appropriate actions are taken.

The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months Completion Time takes into account the capacity

and capability of the remaining AC sources, a reasonable

time for repairs, and the low probability of a DBA occurring

during this period.

G.1 and G.2 Condition G is entered when both offsite circuits required

by LCO 3.8.1.a are inoperable, or when the offsite circuit

required by LCO 3.8.1.c and one offsite circuit required by

LCO 3.8.1.a are concurrently inoperable, if the LCO 3.8.1.a

offsite circuit is credited with providing power to the

CREVS and CRETS.

Required Action G.1 is intended to provide assurance that an event with a coincident single failure will not result in a

complete loss of redundant required safety functions. The

Completion Time for this failure of redundant required

features is reduced to 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months from that allowed for one

train without offsite power (Required Action A.2). The

rationale for the reduction to 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months is that Reference 6

allows a Completion Time of 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months for two required

offsite circuits inoperable, based upon the assumption that

two complete safety trains are OPERABLE. When a concurrent

redundant required feature failure exists, this assumption

is not the case, and a shorter Completion Time of 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months

is appropriate. These features are powered from redundant

AC safety trains. Single train features are not included in the list.

The Completion Time for Required Action G.1 is intended to allow the operator time to evaluate and repair any

discovered inoperabilities. This Completion Time also

allows for an exception to the normal "time zero" for

beginning the allowed outage time "clock." In this Required AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-20 Revision 26 Action, the Completion Time only begins on discovery that both: a. Two required offsite circuits are inoperable; and

b. A required feature is inoperable.

If at any time during the existence of Condition G (e.g., two required LCO 3.8.1.a offsite circuits inoperable) and a required feature becomes inoperable, this Completion

Time begins to be tracked.

Consistent with Reference 6, operation may continue in

Condition G for a period that should not exceed 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months .

This level of degradation means that the offsite electrical

power system does not have the capability to effect a safe

shutdown and to mitigate the effects of an accident;

however, the onsite AC sources have not been degraded. This

level of degradation could correspond to a total loss of the

immediately accessible offsite power sources.

Because of the normally high availability of the offsite sources, this level of degradation may appear to be more

severe than other combinations of two AC sources inoperable

that involve one or more DGs inoperable. However, two

factors tend to decrease the severity of this level of

degradation: a. The configuration of the redundant AC electrical power system that remains available is not susceptible to a

single bus or switching failure; and b. The time required to detect and restore an unavailable offsite power source is generally much less than that

required to detect and restore an unavailable onsite AC

source.

With two of the required offsite circuits inoperable, sufficient onsite AC sources are available to maintain the

unit in a safe shutdown condition in the event of a DBA or

transient. In fact, a simultaneous loss of offsite AC

sources, a loss of coolant accident, and a worst case single

failure were postulated as a part of the design basis in the

safety analysis. Thus, the 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months Completion Time provides

a period of time to effect restoration of one of the offsite

circuits commensurate with the importance of maintaining an AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-21 Revision 26 AC electrical power system capable of meeting its design criteria.

Consistent with Reference 6, with the available offsite AC

sources two less than required by the LCO, operation may

continue for 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months . If two offsite sources are restored within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months , unrestricted operation may continue. If only one offsite source is restored within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months , power

operation continues in accordance with Condition A or D, as

applicable.

H.1 and H.2 Pursuant to LCO 3.0.6, the Distribution System ACTIONS would

not be entered even if all AC sources to it were inoperable

resulting in de-energization. Therefore, the Required

Actions of Condition H are modified by a Note to indicate

that when Condition H is entered with no AC source to any

train, the Conditions and Required Actions for LCO 3.8.9, must be immediately entered. This allows Condition H to

provide requirements for the loss of one required

LCO 3.8.1.a offsite circuit and one LCO 3.8.1.b DG without

regard to whether a train is de-energized. Limiting

Condition for Operation 3.8.9 provides the appropriate

restrictions for a de-energized train.

Consistent with Reference 6, operation may continue in Condition H for a period that should not exceed 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months .

In Condition H, individual redundancy is lost in both the offsite electrical power system and the onsite AC electrical

power system. Since power system redundancy is provided by

two diverse sources of power, however, the reliability of

the power systems in this Condition may appear higher than

that in Condition G (loss of two required offsite circuits).

This difference in reliability is offset by the susceptibility of this power system configuration to a

single bus or switching failure. The 12 hour1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months Completion

Time takes into account the capacity and capability of the

remaining AC sources, a reasonable time for repairs, and the

low probability of a DBA occurring during this period.

AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-22 Revision 26 I.1 With two LCO 3.8.1.b DGs inoperable, there are no remaining standby AC sources to provide power to most of the ESF

systems. With one LCO 3.8.1.c DG inoperable and the

LCO 3.8.1.b DG that provides power to the CREVS and CRETS

inoperable, there are no remaining standby AC sources to the CREVS and CRETS. Thus, with an assumed loss of offsite electrical power, insufficient standby AC sources are

available to power the minimum required ESF functions.

Since the offsite electrical power system is the only source

of AC power for this level of degradation, the risk

associated with continued operation for a short time could

be less than that associated with an immediate controlled

shutdown (the immediate shutdown could cause grid

instability, which could result in a total loss of AC

power). Since any inadvertent generator trip could also

result in a total loss of offsite AC power, however, the

time allowed for continued operation is severely restricted.

The intent here is to avoid the risk associated with an

immediate controlled shutdown and to minimize the risk

associated with this level of degradation.

Consistent with Reference 6, with both LCO 3.8.1.b DGs inoperable, or with the LCO 3.8.1.b DG that provides power

to the CREVS and CRETS and the LCO 3.8.1.c DG inoperable, operation may continue for a period that should not exceed

2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months .

J.1 and J.2 If any Required Action and associated Completion Time of

Conditions A, B.2, B.3, B.4.1, B.4.2, B.5, C, E.2, E.3, E.4.1, E.4.2, E.5, F, G, H, or I are not met, the unit must

be brought to a MODE in which the LCO does not apply. To

achieve this status, the unit must be brought to at least MODE 3 within six hours and to MODE 5 within 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months . The allowed Completion Times are reasonable, based on operating

experience, to reach the required unit conditions from full

power conditions in an orderly manner and without

challenging unit systems.

AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-23 Revision 26 K.1 Condition K corresponds to a level of degradation in which all redundancy in LCO 3.8.1.a and LCO 3.8.1.b AC electrical

power supplies has been lost. At this severely degraded

level, any further losses in the AC electrical power system

will cause a loss of function. Therefore, no additional time is justified for continued operation. The unit is

required by LCO 3.0.3 to commence a controlled shutdown.

SURVEILLANCE The AC sources are designed to permit inspection and REQUIREMENTS testing of all important areas and features, especially those that have a standby function, in accordance with

Reference 1, GDC 18. Periodic component tests are

supplemented by extensive functional tests during refueling

outages (under simulated accident conditions). The SRs for

demonstrating the OPERABILITY of the DGs are consistent with

the recommendations of Reference 3, or Reference 4, and

Reference 8.

When the SRs discussed herein specify voltage and frequency tolerances, the following is applicable. The minimum

transient output voltage of 3740 V is 90% of the nominal

4160 V output voltage. This value allows for voltage drop

to the terminals of 4000 V motors whose minimum operating

voltage is specified as 90% or 3600 V. The specified

maximum output voltage of 4400 V is equal to the maximum

operating voltage specified for 4000 V motors. It ensures

that for a lightly loaded distribution system, the voltage

at the terminals of 4000 V is no more than the maximum rated

operating voltages. The specified minimum and maximum frequencies of the DG are 58.8 Hz and 61.2 Hz, respectively.

These values are equal to +/- 2% of the 60 Hz nominal

frequency and are the recommendations given in Reference 3.

The SRs are modified by a Note which states that SR 3.8.1.1 through SR 3.8.1.15 are applicable to LCO 3.8.1.a and

LCO 3.8.1.b AC Sources. The Note also states that

SR 3.8.1.16 is applicable to LCO 3.8.1.c AC sources. This

Note clarifies that not all of the SRs are applicable to all

the components described in the LCO.

AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-24 Revision 26 SR 3.8.1.1 and SR 3.8.1.2 These SRs assure proper circuit continuity for the offsite AC electrical power supply to the onsite distribution

network and availability of offsite AC electrical power.

The breaker alignment verifies that each breaker is in its

correct position to ensure that distribution buses and loads are connected to their preferred power source, and that appropriate independence of offsite circuits is maintained.

The Frequency of once within one hour after substitution for

a 500 kV circuit and every eight hours thereafter, for

SR 3.8.1.1 was established to ensure that the breaker

alignment for the SMECO circuit (which does not have Control

Room indication) is in its correct position although breaker

position is unlikely to change. The seven day Frequency for

SR 3.8.1.2 is adequate since the 500 kV circuit breaker

position is not likely to change without the operator being

aware of it and because its status is displayed in the

Control Room.

Surveillance Requirement 3.8.1.1 is modified by a Note which states that this SR is only required when SMECO is being

credited for an offsite source. This SR will prevent

unnecessary testing on an uncredited circuit.

SR 3.8.1.3 and SR 3.8.1.9 These SRs help to ensure the availability of the standby

electrical power supply to mitigate DBAs and transients and

to maintain the unit in a safe shutdown condition.

To minimize the wear on moving parts that do not get

lubricated when the engine is not running, these SRs are

modified by a Note (Note 2 for SR 3.8.1.3) to indicate that

all DG starts for these surveillance tests may be preceded

by an engine prelube period and followed by a warmup period prior to loading by an engine prelube period.

For the purposes of SR 3.8.1.9 testing, the DGs are required to start from standby conditions only for SR 3.8.1.9.

Standby conditions for a DG mean the diesel engine coolant

and oil are being continuously circulated and temperature is

being maintained consistent with manufacturer

recommendations.

AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-25 Revision 26 In order to reduce stress and mechanical wear on diesel

engines, the DG manufacturers recommend a modified start in

which the starting speed of DGs is limited, warmup is

limited to this lower speed, and the DGs are gradually

accelerated to synchronous speed prior to loading. This is the intent of Note 3, which is only applicable when such modified start procedures are recommended by the

manufacturer.

Surveillance Requirement 3.8.1.9 requires that, at a 184 day

Frequency, the DG starts from standby conditions and

achieves required voltage and frequency within 10 seconds.

The minimum voltage and frequency stated in the SR are those

necessary to ensure the DG can accept DBA loading while

maintaining acceptable voltage and frequency levels. The

10 second start requirement supports the assumptions of the

design basis loss of coolant accident analysis in

Reference 2, Chapter 14.

Since SR 3.8.1.9 requires a 10 second start, it is more restrictive than SR 3.8.1.3, and it may be performed in lieu

of SR 3.8.1.3.

The 31 day Frequency for SR 3.8.1.3 is consistent with Reference 4 and Reference 3. The 184 day Frequency for

SR 3.8.1.9 is a reduction in cold testing consistent with

Reference 7. This Frequency provides adequate assurance of

DG OPERABILITY, while minimizing degradation resulting from

testing.

SR 3.8.1.4 This SR verifies that the DGs are capable of synchronizing

with the offsite electrical system and accepting loads greater than or equal to 4000 kW for No. 1A DG and greater than or equal to 90% of the continuous duty rating for the

remaining DGs. The 90% minimum load limit is consistent

with Reference 3 and is acceptable because testing of these

DGs at post-accident load values is performed by

SR 3.8.1.11. A minimum run time of 60 minutes is required

to stabilize engine temperatures, while minimizing the time

that the DG is connected to the offsite source.

AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-26 Revision 26 Although no power factor requirements are established by this SR, the DG is normally operated at a power factor

between 0.8 lagging and 1.0. The 0.8 value is the design

rating of the machine, while 1.0 is an operational

limitation. The 31-day Frequency for this SR is consistent

with Reference 3.

This SR is modified by four Notes. Note 1 indicates that

the diesel engine runs for this surveillance test may

include gradual loading, as recommended by the manufacturer, so that mechanical stress and wear on the diesel engine are

minimized. Note 2 states that momentary transients because

of changing bus loads do not invalidate this test. Note 3

indicates that this surveillance test shall be conducted on

only one DG at a time in order to prevent routinely

paralleling multiple DGs and to minimize the potential for

effects from offsite circuit or grid perturbations. Note 4

stipulates a prerequisite requirement for performance of

this SR. A successful DG start must precede this test to

credit satisfactory performance.

SR 3.8.1.5 This SR provides verification that the level of fuel oil in

the day tank is at or above the level at which fuel oil is

automatically added. The level required by the SR is

expressed as an equivalent volume in gallons, and is

selected to ensure adequate fuel oil for a minimum of

one hour of DG operation at full load plus 10%.

The 31-day Frequency is adequate to assure that a sufficient supply of fuel oil is available, since low level alarms are

provided, and unit operators would be aware of any large

uses of fuel oil during this period.

SR 3.8.1.6 Microbiological fouling is a major cause of fuel oil degradation. There are numerous bacteria that can grow in

fuel oil and cause fouling, but all must have a water

environment in order to survive. Removal of water from the

fuel oil day tanks once every 31 days eliminates the

necessary environment for bacterial survival. This is the

most effective means of controlling microbiological fouling.

AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-27 Revision 26 In addition, it eliminates the potential for water entrainment in the fuel oil during DG operation. Water may

come from any of several sources, including condensation, ground water, rain water, contaminated fuel oil, and from

breakdown of the fuel oil by bacteria. Frequent checking

for and removal of accumulated water minimizes fouling and provides data regarding the watertight integrity of the fuel oil system. The SR Frequencies are consistent with

Reference 8. This SR is for preventive maintenance. The

presence of water does not necessarily represent failure of

this SR provided the accumulated water is removed during the

performance of this surveillance test.

SR 3.8.1.7 This SR demonstrates that one fuel oil transfer pump

operates and transfers fuel oil from its associated storage

tank to its associated day tank. This is required to

support continuous operation of standby power sources. This

SR provides assurance that the fuel oil transfer pump is

OPERABLE, the fuel oil piping system is intact, the fuel

delivery piping is not obstructed, and the controls and

control systems for automatic fuel transfer systems are

OPERABLE.

The Frequency for this SR is 31 days. The 31-day Frequency corresponds to the design of the fuel transfer system. The

design of fuel transfer systems is such that pumps will

operate automatically or must be started manually in order

to maintain an adequate volume of fuel oil in the day tanks

during or following DG testing. In such a case, a 31-day

Frequency is appropriate.

SR 3.8.1.8 Under accident and loss of offsite power conditions loads are sequentially connected to the bus by the automatic load sequencer (this SR verifies steps 1 through 5). The

sequencing logic controls the permissive and closing signals

to breakers to prevent overloading of the DGs due to high

motor starting currents. The 10% load sequence time

interval tolerance ensures that sufficient time exists for

the DG to restore frequency and voltage prior to applying

the next load, and that safety analysis assumptions AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-28 Revision 26 regarding ESF equipment time delays are not violated. The UFSAR provides a summary of the automatic loading of ESF

buses.

The Frequency of 31 days is consistent with DG monthly

testing and is sufficient to ensure the load sequencer operation as required.

SR 3.8.1.9 See SR 3.8.1.3.

SR 3.8.1.10 Transfer of each 4.16 kV ESF bus power supply from the

normal offsite circuit to the alternate offsite circuit

demonstrates the OPERABILITY of the alternate circuit

distribution network to power the shutdown loads. The

24 month Frequency of the Surveillance is based on

engineering judgment, taking into consideration the unit

conditions required to perform the Surveillance, and is

intended to be consistent with expected fuel cycle lengths.

Operating experience has shown that these components usually

pass the SR when performed at the 24 month Frequency.

Therefore, the Frequency was concluded to be acceptable from

a reliability standpoint.

SR 3.8.1.11 This SR provides verification that the DG can be operated at

a load greater than predicted accident loads for at least

60 minutes once per 24 months. Operation at the greater

than calculated accident loads will clearly demonstrate the

ability of the DGs to perform their safety function. In

order to ensure that the DG is tested under load conditions

that are as close to design conditions as possible, testing

must be performed using a DG load greater than or equal to calculated accident load and using a power factor 0.85. This power factor is chosen to be representative of the actual design basis inductive loading that the DG could

experience. In addition, the post-accident load for No. 1A

DG is significantly lower than the continuous rating of

No. 1A DG. To ensure No. 1A DG performance is not degraded, routine monitoring of engine parameters should be performed AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-29 Revision 26 during the performance of this SR for No. 1A DG (Reference 9).

This SR is modified by a Note which states that momentary

transients due to changing bus loads do not invalidate this

test. Similarly, momentary power factor transients above the limit will not invalidate the test. The 24 month Frequency is adequate to ensure DG OPERABILITY and it is

consistent with the refueling interval.

SR 3.8.1.12 Each DG is provided with an engine overspeed trip to prevent

damage to the engine. Recovery from the transient caused by

the loss of a large load could cause diesel engine

overspeed, which, if excessive, might result in a trip of

the engine. This SR demonstrates the DG load response

characteristics. This SR is accomplished by tripping the DG

output breaker with the DG carrying greater than or equal to

its associated single largest post-accident load while

paralleled to offsite power.

Consistent with References 10, 3, and 4, the load rejection test is acceptable if the increase in diesel speed does not

exceed 75% of the difference between synchronous speed and

the overspeed trip setpoint, or 15% above synchronous speed, whichever is lower.

The 24 month Frequency is consistent with the Reference 2, Chapter 8.

SR 3.8.1.13 This SR demonstrates that DG non-critical protective

functions are bypassed on a required actuation signal. This

SR is accomplished by verifying the bypass contact changes to the correct state which prevents actuation of the non-critical function. The non-critical protective functions

are consistent with References 3 and 4, and Institute of

Electrical and Electronic Engineers (IEEE)-387 and are

listed in Reference 2, Chapter 8. Verifying the non-

critical trips are bypassed will ensure DG operation during

a required actuation. The non-critical trips are bypassed

during DBAs and provide an alarm on an abnormal engine AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-30 Revision 26 condition. A failure of the electronic governor results in the diesel generator operating in hydraulic mode. This

alarm provides the operator with sufficient time to react

appropriately. The DG availability to mitigate the DBA is

more critical than protecting the engine against minor

problems that are not immediately detrimental to emergency operation of the DG.

The 24 month Frequency is based on engineering judgment, taking into consideration unit conditions required to

perform the surveillance test, and is intended to be

consistent with expected fuel cycle lengths. Operating

experience has shown that these components usually pass the

SR when performed at the 24 month Frequency. Therefore, the

Frequency was concluded to be acceptable from a reliability

standpoint. This Frequency is consistent with Reference 2, Chapter 8.

SR 3.8.1.14 This SR ensures that the manual synchronization and load

transfer from the DG to the offsite source can be made and

that the DG can be returned to ready-to-load status when

offsite power is restored. The DG is considered to be in

ready-to-load status when the DG is at rated speed and

voltage, the output breaker is open and can receive an auto-

close signal on bus undervoltage, and the load sequence

timers are reset.

The Frequency of 24 months takes into consideration unit conditions required to perform the surveillance test.

SR 3.8.1.15 In the event of a DBA coincident with a loss of offsite

power, the DGs are required to supply the necessary power to ESF systems so that the fuel, RCS, and containment design limits are not exceeded.

This SR demonstrates the DG operation during a loss of offsite power actuation test signal in conjunction with an

ESF (i.e., safety injection) actuation signal. In lieu of

actual demonstration of connection and loading of loads, testing that adequately shows the capability of the DG AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-31 Revision 26 system to perform these functions is acceptable. This testing may include any series of sequential, overlapping, or total steps so that the entire connection and loading

sequence is verified.

It is not necessary to energize loads which are dependent on temperature to load (i.e., heat tracing, switchgear HVAC compressor, computer room HVAC compressor). Also, it is

acceptable to transfer the instrument AC bus to the non

tested train to maintain safe operation of the plant during

testing. Loads (both permanent and auto connect) < 15 kW do

not require loading onto the diesel since these are

insignificant loads for the DG.

Permanently- and auto-connected loads to the emergency diesel generators are defined as follows:

Permanently-Connected Load - Equipment that is not shed by an undervoltage or safety injection actuation signal and is

normally operating, i.e., loads that are manually started, selected, or process signal controlled are not considered

permanently-connected loads.

Auto-Connected Loads - Emergency equipment required for mitigating the events described in UFSAR Chapter 14 that are

energized by loss-of-coolant incident sequencer actions

after step zero and within the first minute of emergency

diesel generator operation after the initiation of an

undervoltage signal.

The Frequency of 24 months takes into consideration unit conditions required to perform the surveillance test and is

intended to be consistent with an expected fuel cycle length

of 24 months.

This SR is modified by a Note. The reason for the Note is to minimize mechanical wear and stress on the DGs during

testing. For the purpose of this testing, the DGs must be

started from standby conditions, that is, with the engine

coolant and oil continuously circulated and temperature

maintained consistent with manufacturer recommendations for

DGs.

AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-32 Revision 26 SR 3.8.1.16 This SR lists the SRs that are applicable to the LCO 3.8.1.c (SRs 3.8.1.1, 3.8.1.2, 3.8.1.3, 3.8.1.5, 3.8.1.6, and

3.8.1.7). Performance of any SR for the LCO 3.8.1.c will

satisfy both Unit 1 and Unit 2 requirements for those SRs.

Surveillance Requirements 3.8.1.4, 3.8.1.8, 3.8.1.9, 3.8.1.10, 3.8.1.11, 3.8.1.12, 3.8.1.13, 3.8.1.14, and 3.8.1.15, are not required to be performed for the

LCO 3.8.1.c. Surveillance Requirement 3.8.1.10 is not

required because this SR verifies manual transfer of AC

power sources from the normal offsite circuit to the

alternate offsite circuit, but only one qualified offsite

circuit is necessary for the LCO 3.8.1.c. Surveillance

Requirements 3.8.1.4, 3.8.1.11, and 3.1.8.12 are not

required because they are tests that deal with loads.

Surveillance Requirement 3.8.1.8 verifies the interval

between sequenced loads. Surveillance Requirement 3.8.1.14

verifies the proper sequencing with offsite power.

Surveillance Requirement 3.8.1.9 verifies that the DG starts

within 10 seconds. These SRs are not required because they

do not support the function of the LCO 3.8.1.c to provide

power to the CREVS and CRETS. Surveillance Requirements

3.8.1.13 and 3.8.1.15 are not required to be performed

because these SRs verify the emergency loads are actuated on

an ESFAS signal for the Unit in which the test is being

performed. The LCO 3.8.1.c DG will not start on an ESFAS signal for this Unit.

REFERENCES 1. 10 CFR Part 50, Appendix A, "General Design Criteria for Nuclear Power Plants" 2. UFSAR 3. Regulatory Guide 1.9, Revision 3, "Selection, Design, Qualification, and Testing of Emergency Diesel Generator Units Used as Class 1E Onsite Electric Power

Systems at Nuclear Power Plants," July 1993 4. Safety Guide 9, Revision 0, March 1971 5. NRC Safety Evaluation for Amendment Nos. 19 and 5 for Calvert Cliffs Nuclear Power Plant Unit Nos. 1 and 2, dated January 14, 1977 6. Regulatory Guide 1.93, Revision 0, "Availability of Electric Power Sources," December 1974 AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-33 Revision 26

7. Generic Letter 84-15, Proposed Staff Actions to Improve and Maintain Diesel Generator Reliability, July 2, 1984

8. Regulatory Guide 1.137, Revision 1, "Fuel-Oil Systems for Standby Diesel Generators," October 1979

9. Letter from Mr. D. G. McDonald, Jr. (NRC) to Mr. C. H. Cruse (BGE), dated April 2, 1996, Issuance of Amendments for Calvert Cliffs Nuclear Power Plant, Unit 1 (TAC No. M94030) and Unit 2 (TAC No. M94031)

10. IEEE Standard 308-1991, "IEEE Standard Criteria for Class 1E Power Systems for Nuclear Power Generating

Stations" 11. NO-1-117, Integrated Risk Management

AC Sources-Shutdown B 3.8.2 B 3.8 ELECTRICAL POWER SYSTEMS B 3.8.2 AC Sources-Shutdown

BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.2-1 Revision 2 BACKGROUND A description of the AC sources is provided in the Bases for LCO 3.8.1. APPLICABLE The OPERABILITY of the minimum AC sources during MODE s 5 SAFETY ANALYSES and 6 and during movement of irradiated fuel assemblies ensures that:

a. The unit can be maintained in the shutdown or refueling condition for extended periods;

b. Sufficient instrumentation and control capability is available for monitoring and maintaining the unit

status; and c. Adequate AC electrical power is provided to mitigate events postulated during shutdown, such as a fuel

handling accident.

In general, when the unit is shut down, the Technical Specifications requirements ensure that the unit has the

capability to mitigate the consequences of postulated

accidents. However, assuming a single failure and

concurrent loss of all offsite or all onsite power is not

required. The rationale for this is based on the fact that

many DBAs that are analyzed in MODE s 1, 2, 3, and 4 have no specific analyses in MODE s 5 and 6. Worst case bounding events are deemed not credible in MODE s 5 and 6 because the energy contained within the reactor pressure boundary, reactor coolant temperature and pressure, and the

corresponding stresses result in the probabilities of

occurrence being significantly reduced or eliminated, and in minimal consequences. These deviations from DBA analysis assumptions and design requirements during shutdown

conditions are allowed by the LCO for required systems.

During MODE s 1, 2, 3, and 4, various deviations from the analysis assumptions and design requirements are allowed

within the Required Actions. This allowance is in

recognition that certain testing and maintenance activities

must be conducted provided an acceptable level of risk is

not exceeded. During MODE s 5 and 6, performance of a significant number of required testing and maintenance AC Sources-Shutdown B 3.8.2 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.2-2 Revision 2 activities is also required. In MODE s 5 and 6, the activities are generally planned and administratively controlled. Relaxations from MODE s 1, 2, 3, and 4 LCO requirements are acceptable during shutdown MODE s based on:

a. The fact that time in an outage is limited. This is a risk prudent goal as well as a utility economic consideration. b. Requiring appropriate compensatory measures for certain conditions. These may include administrative controls, reliance on systems that do not necessarily meet

typical design requirements applied to systems credited

in operating MODE analyses, or both. c. Prudent utility consideration of the risk associated with multiple activities that could affect multiple

systems. d. Maintaining, to the extent practical, the ability to perform required functions (even if not meeting

MODE s 1, 2, 3, and 4 OPERABILITY requirements) with systems assumed to function during an event.

In the event of an accident during shutdown, this LCO

ensures the capability to support systems necessary to avoid

immediate difficulty, assuming either a loss of all offsite

power or a loss of all onsite DG power. The AC sources satisfy 10 CFR 50.36(c)(2)(ii), Criterion 3.

LCO One offsite circuit capable of supplying the onsite Class 1E

power distribution subsystem(s) of LCO 3.8.10 , ensures that all required loads are powered from offsite power. An OPERABLE DG, associated with a distribution system train required to be OPERABLE by LCO 3.8.10, ensures a diverse

power source is available to provide electrical power

support, assuming a loss of the offsite circuit. Together, OPERABILITY of the required offsite circuit and DG ensures

the availability of sufficient AC sources to operate the

unit in a safe manner and to mitigate the consequences of

postulated events during shutdown (e.g., fuel handling

accidents).

AC Sources-Shutdown B 3.8.2 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.2-3 Revision 10 The qualified offsite circuit must be capable of maintaining rated frequency and voltage, and accepting required loads

during an accident, while connected to the ESF bus(es).

Qualified offsite circuits are those that are described in

the UFSAR and are part of the licensing basis for the unit.

The DG must be capable of starting, accelerating to rated speed and voltage, connecting to its respective ESF bus, and

accepting required loads. The DG must continue to operate

until offsite power can be restored to the ESF buses.

These capabilities are required to be met from a variety of

initial conditions such as DG in standby with the engine hot

and DG in standby at ambient conditions.

It is acceptable for trains to be cross-tied during shutdown

conditions, allowing a single offsite power circuit to

supply all required trains.

The CREVS and CRETS are shared systems with one train of each system connected to an onsite Class 1E AC electrical

power distribution subsystem from each unit. Limiting

Condition for Operation 3.8.2.c requires one qualified

circuit between the offsite transmission network and the

other unit's onsite Class 1E AC electrical power

distribution subsystems needed to supply power to the CREVS

and CRETS to be OPERABLE. Limiting Condition for

Operation 3.8.2.d requires one DG from the other unit

capable of supplying power to the required CREVS and CRETS

to be OPERABLE, if the DG required by LCO 3.8.2.b is not

capable of supplying power to the required CREVS and CRETS.

These requirements, in conjunction with the requirements for

the unit AC electrical power sources in LCO 3.8.2.a and

LCO 3.8.2.b, ensure that offsite power is available to both

trains and onsite power is available to one train of the CREVS and CRETS, when they are required to be OPERABLE by

their respective LCOs (LCOs 3.7.8 and 3.7.9).

AC Sources-Shutdown B 3.8.2 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.2-4 Revision 5 APPLICABILITY The AC sources required to be OPERABLE in MODEs 5 and 6 and during movement of irradiated fuel assemblies provide assurance that:

a. Systems to provide adequate coolant inventory makeup are available for the irradiated fuel assemblies;

b. Systems needed to mitigate a fuel handling accident are available;

c. Systems necessary to mitigate the effects of events that can lead to core damage during shutdown are

available; and

d. Instrumentation and control capability is available for monitoring and maintaining the unit in a cold shutdown

condition or refueling condition.

The AC power requirements for MODEs 1, 2, 3, and 4 are covered in LCO 3.8.1.

ACTIONS Limiting Condition for Operation 3.0.3 is not applicable while in MODEs 5 or 6. However, since irradiated fuel

assembly movement can occur in MODEs 1, 2, 3, or 4, the

ACTIONS have been modified by a Note stating that LCO 3.0.3

is not applicable. If moving irradiated fuel assemblies

while in MODEs 5 or 6, LCO 3.0.3 would not specify any

action. If moving irradiated fuel assemblies while in

MODEs 1, 2, 3, or 4, the fuel movement is independent of

reactor operations. Therefore, in either case, inability to

suspend movement of irradiated fuel assemblies would not be

sufficient reason to require a reactor shutdown.

The ACTIONS have been modified by a second Note stating that performance of Required Actions shall not preclude

completion of actions to establish a safe conservative

position. This clarification is provided to avoid stopping

movement of irradiated fuel assemblies while in a non-

conservative position based on compliance with the Required

Actions.

A.1 An offsite circuit would be considered inoperable, if it was

unavailable to one required ESF train. Although two trains

may be required by LCO 3.8.10, the remaining train with AC Sources-Shutdown B 3.8.2 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.2-5 Revision 29 offsite power available may be capable of supporting sufficient required features to allow continuation of fuel movement. By the allowance of the option to declare

required features inoperable, with no offsite power

available, appropriate restrictions will be implemented in

accordance with the affected required features LCO's ACTIONS. A.2.1, A.2.2, A.2.3, B.1, B.2, and B.3 With the offsite circuit not available to all required

trains, the option would still exist to declare all required

features inoperable. Since this option may involve

undesired administrative efforts, the allowance for

sufficiently conservative actions is made. With the

required DG inoperable, the minimum required diversity of AC

power sources is not available. It is, therefore, required

to suspend movement of irradiated fuel assemblies, and operations involving positive reactivity additions that

could result in loss of the required SHUTDOWN MARGIN (SDM)

(MODE 5) or boron concentration (MODE 6). Suspending

positive reactivity additions that could result in failure

to meet the minimum SDM or boron concentration limit is

required to assure continued safe operation. Introduction

of coolant inventory must be from sources that have a boron

concentration greater than that required in the RCS for the

minimum SDM or refueling boron concentration. This may

result in an overall reduction in RCS boron concentration, but provides an acceptable margin to maintaining subcritical

operation. Introduction of temperature changes including

temperature increases when operating with a positive

moderator temperature coefficient (MTC) must also be

evaluated to ensure they do not result in a loss of the

required SDM.

Suspension of these activities does not preclude completion of actions to establish a safe conservative condition.

These actions minimize the probability or the occurrence of

postulated events. It is further required, to immediately

initiate action to restore the required AC sources and to

continue this action until restoration is accomplished in

order to provide the necessary AC power to the unit safety

systems.

AC Sources-Shutdown B 3.8.2 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.2-6 Revision 19 The Completion Time of immediately is consistent with the required times for actions requiring prompt attention. The

restoration of the required AC electrical power sources

should be completed as quickly as possible in order to

minimize the time during which the unit safety systems may

be without sufficient power.

Pursuant to LCO 3.0.6, the Electrical Distribution System's

ACTIONS are not entered even if all AC sources to it are

inoperable, resulting in de-energization. Therefore, the

Required Actions of Condition A are modified by a Note to

indicate that when Condition A is entered with no AC power

to any required ESF bus, the ACTIONS for LCO 3.8.10 must be

immediately entered. This Note allows Condition A to

provide requirements for the loss of the offsite circuit, whether or not a train is de-energized. Limiting Condition

for Operation 3.8.10 provides the appropriate restrictions for the situation involving a de-energized train.

SURVEILLANCE SR 3.8.2.1 and SR 3.8.2.2 REQUIREMENTS

Surveillance Requirements 3.8.2.1 and 3.8.2.2 require the

performance of SRs from LCO 3.8.1 that are necessary for

ensuring the OPERABILITY of the AC sources in other than

MODEs 1, 2, 3, and 4. Surveillance Requirement 3.8.1.10 is

not required to be met, since only one offsite circuit is

required to be OPERABLE. Surveillance Requirements 3.8.1.4, 3.8.1.8, 3.8.1.13, and 3.8.1.15 are related to automatic

starting of the DGs for an operating unit, which is not

applicable for a shutdown unit. Surveillance Requirement 3.8.1.16 is related to LCO 3.8.2.c and 3.8.2.d AC sources, and is addressed by SR 3.8.2.2.

Surveillance Requirement 3.8.2.1 is modified by a Note. The Note lists SRs not required to be performed in order to

preclude de-energizing a required 4.16 kV ESF bus or

disconnecting a required offsite circuit during performance

of SRs. With limited AC Sources available, a single event

could compromise both the required circuit and the DG. It

is the intent that these SRs must still be capable of being

met, but actual performance is not required during periods

when the DG and offsite circuit are required to be OPERABLE.

AC Sources-Shutdown B 3.8.2 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.2-7 Revision 19 Refer to the corresponding Bases for LCO 3.8.1 for a discussion of each SR.

REFERENCES None

Diesel Fuel Oil B 3.8.3 B 3.8 ELECTRICAL POWER SYSTEMS B 3.8.3 Diesel Fuel Oil

BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.3-1 Revision 2 BACKGROUND The fuel oil storage tanks (FOSTs) contain sufficient capability for the DGs to operate one unit on accident loads and one unit on shutdown loads for seven days. This is discussed in Reference 1 , Chapter 8. This onsite fuel oil capacity is sufficient to operate the DGs for longer than the time to replenish the onsite supply from outside

sources.

Fuel oil is transferred from the storage tanks to the day

tank by transfer pumps associated with each DG.

For proper operation of the standby DGs, it is necessary to ensure the proper quality of the fuel oil. Testing to check

for water and sediment content, the kinematic viscosity, specific gravity (or API gravity), and impurity level (i.e., total particulates) ensures this quality.

The DG fuel oil system design at Calvert Cliffs supports four emergency DGs and other non-safety DGs. Three of the

four emergency DGs, i.e., Nos. 1B, 2A, and 2B, are fueled

from two FOSTs , i.e., FOST Nos. 11 and 21, and DG No. 1A is fueled from FOST No. 1A. F uel O il S torage T ank Nos. 1A and 21 are enclosed such as to be considered "tornado protected" but FOST No. 11 is not protected. As such, FOST No. 11 is not used as the primary source for the emergency DGs, but

rather is used as a backup to support FOST No. 21 , if it or the fuel oil it contains becomes degraded.

The operability of FOST Nos. 21 and 11 ensure that at least

seven days of fuel oil will be reserved below the internal tank standpipes for operation of one DG on each unit, assuming one unit under accident conditions with a DG load of 3500 kW, and the opposite unit under normal shutdown conditions with a DG load of 3000 kW. Additionally, the

operability of FOST No. 21 ensures that in the event of a loss of offsite power, concurrent with a loss of the non-

bunkered FOST (tornado/missile event), at least seven days of fuel oil will be available for operation of one DG on

each unit, assuming both DGs are loaded to 3000 kW. The

operability of the FOST No. 1A ensures that at least Diesel Fuel Oil B 3.8.3 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.3-2 Revision 2 seven days of fuel oil is available to support operation of DG No. 1A at 4000 kW.

The operability of the fuel oil day tanks ensures that at

least one hour of DG operation is available without makeup to the day tanks, assuming DG No. 1A is loaded to 4000 kW and DG No s. 1B, 2A, and 2B are loaded to 3500 kW.

APPLICABLE The initial conditions of DBA and transient analyses in SAFETY ANALYSES Reference 1, and Chapter s 6 and 14 , assume ESF systems are OPERABLE. The DGs are designed to provide sufficient

capacity, capability, redundancy, and reliability to ensure

the availability of necessary power to ESF systems so that

fuel, RCS, and containment design limits are not exceeded.

These limits are discussed in more detail in the Bases for

LCO Section 3.2 , 3.4 , and 3.6.

Since diesel fuel oil supports the operation of the standby

AC power sources, they satisfy 10 CFR 50.36(c)(2)(ii), Criterion 3.

LCO F uel O il S torage T ank No. 1A is required to contain a minimum of 49,500 gallons of available diesel fuel oil which

is a sufficient supply to operate DG No. 1A with accident loads for seven days. F uel O il S torage T ank No. 21 is required to contain a minimum of 85,000 gallons of available

diesel fuel oil which is a sufficient supply to operate one unit with accident loads and one unit with shutdown loads for seven days. It is also required to meet specific standards for quality. This requirement, in conjunction

with an ability to obtain replacement supplies within

seven days, supports the availability of DGs required to shut down the reactor and to maintain it in a safe condition

for an AOO or a postulated DBA with loss of offsite power.

Diesel generator day tank fuel requirements, as well as

transfer capability from the FOST to the day tank, are addressed in LCO 3.8.1 and LCO 3.8.2

. APPLICABILITY The AC sources (LCO 3.8.1 and LCO 3.8.2) are required to ensure the availability of the required power to shut down

the reactor and maintain it in a safe shutdown condition

after an AOO or a postulated DBA. Since stored diesel fuel

oil supports LCO 3.8.1 and LCO 3.8.2, stored diesel fuel oil Diesel Fuel Oil B 3.8.3 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.3-3 Revision 2 is required to be within limits when the associated DG is required to be OPERABLE.

For both Unit 1 and Unit 2, the FOST No. 1A associated DG is only DG No. 1A. For Unit 1, the FOST No. 21 associated DGs are DG Nos. 1B and 2B. For Unit 2, the FOST No. 21 associated DGs are DG Nos. 2A and 2B. Alignment does not affect the association of DG and FOST since the individual

DG fuel oil day tank provides sufficient volume for the DG

to perform its safety function while re-alignment is accomplished, if necessary.

ACTIONS The ACTIONS Table is modified by a Note indicating that separate Condition entry is allowed for each DG. This is

acceptable, since the Required Actions for each Condition

provide appropriate compensatory actions for each inoperable

DG subsystem. Complying with the Required Actions for one

inoperable DG subsystem may allow for continued operation, and subsequent inoperable DG subsystem(s) are governed by

separate Condition entry and application of associated

Required Actions.

A.1, B.1, B.2, C.1, C.2, and C.3 In this Condition, the seven day fuel oil supply for a DG is not available. However, fuel oil volume reduction is

limited to 6/7 of the required volume which will provide

sufficient capacity to operate one DG on one unit on

accident loads

, and one DG on the other unit on shutdown loads for approximately six days. These circumstances may be caused by events such as full load operation required after an inadvertent start while at minimum required level; or feed and bleed operations, which may be necessitated by

increasing particulate levels or any number of other oil

quality degradations. This restriction allows sufficient

time for obtaining the requisite replacement volume and

performing the analyses required prior to addition of fuel

oil to the tank. A period of 48 hours5.555556e-4 days 0.0133 hours 7.936508e-5 weeks 1.8264e-5 months is considered

sufficient to complete restoration of the required level

prior to declaring the DG inoperable. This period is

acceptable based on the remaining capacity (approximately

six days), the fact that procedures will be initiated to Diesel Fuel Oil B 3.8.3 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.3-4 Revision 2 obtain replenishment, and the low probability of an event during this brief period.

Condition A addresses only FOST No. 1A which is "tornado protected" and which contains sufficient fuel for seven days of required operation of DG No. 1A. It supports both Unit 1 and Unit 2 equipment since DG No. 1A provides power for equipment which is shared by both units, e.g., the CREVS.

Condition B addresses only FOST No. 21 which is "tornado protected" and which contains sufficient fuel for seven days of required operation of two DGs. F uel O il S torage T ank No. 21 supports both Unit 1 and Unit 2 equipment, but Condition B is written for Unit 1 only to reflect the Unit 1

requirements for DG Nos. 1B and 2B. For an accident, Unit 1 requires either DG No. 1A or both DG Nos. 1B and 2B (since DG No. 2B powers equipment which is redundant to some equipment powered by DG No. 1A, e.g., CREVS). Since DG No. 1A is supported by FOST No. 1A and the redundant required equipment is powered by DG Nos. 1B and 2B which are supported by FOST No. 21, at least one full train of required equipment is supported by a "tornado protected"

FOST even with an inoperable FOST or DG. Therefore, low

fuel oil volume in FOST No. 21 can be supplemented by the fuel oil volume of an OPERABLE FOST No. 11 to assure the necessary volume. Required Action B.1 requires the combined

volume of FOST No. 21 and an OPERABLE FOST No. 11 to be verified to be greater than 6/7 of the required volume

within one hour. The Completion Time of one hour is consistent with the time needed to verify through

administrative means that the backup FOST is OPERABLE.

Required Action B.2 requires the combined volume of FOST No. 21 and an OPERABLE FOST No. 11 to be 85,000 gallons within 48 hours5.555556e-4 days 0.0133 hours 7.936508e-5 weeks 1.8264e-5 months . In addition, if FOST No. 21 is not restored and FOST No. 11 continues to be relied upon, Required Action B.2 must be repeated every 31 days. This effectively replaces the SR 3.8.3.1 periodic surveillance of

available DG fuel oil volume for the inoperable FOST No. 21. Since FOST No. 11 is not required by the LCO, FOST No. 11 may be considered OPERABLE only when the stored fuel oil

meets SR 3.8.3.2 and SR 3.8.3.3, and is capable of being

delivered to the required DG, i.e., the necessary piping and

valves are capable of performing their safety function.

Diesel Fuel Oil B 3.8.3 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.3-5 Revision 2 Specific alignment to a particular FOST is not required since the individual DG fuel oil day tank provides

sufficient volume for the DG to perform its safety function

while re-alignment is accomplished, if necessary. Further, if any fuel oil in FOST No. 11 above the 33,000 gallons reserved for emergency DG use is credited for DG use, appropriate administrative controls must be in place to assure its retention for this purpose.

Condition C also addresses only FOST No. 21 which is "tornado protected" and which contains sufficient fuel for

seven days of required operation of two DGs. F uel O il S torage T ank No. 21 supports both Unit 1 and Unit 2 equipment, but Condition C is written for Unit 2 only to

reflect the Unit 2 requirements for DG Nos. 2A and 2B. For an accident, Unit 2 requires either DG No. 2B or both DG Nos. 1A and 2A (since DG No. 1A powers equipment which is redundant to some equipment powered by DG No. 2B, e.g., CREVS). Unlike Unit 1, at least one full train of

required equipment is not supported by a "tornado protected"

FOST with an inoperable FOST or DG since most of the

redundant required equipment is powered by DG Nos. 2A and 2B which are both supported by FOST No. 21. Therefore, low fuel oil volume in FOST No. 21 can only be supplemented by the fuel oil volume of an OPERABLE FOST No. 11 to assure the necessary volume when the probability for a tornado is

sufficiently low. This is reflected in Note 2 for Required

Action C.2 which addresses the inoperability of FOST No. 21 from April 1 to September 30. During the time of low

tornado probability, the Unit 2 requirements for the

inoperability of FOST No. 21 are very similar to the Unit 1 requirements for inoperability of FOST No. 21. It is acceptable for the combined volume of FOST No. 11 and FOST No. 21 to be considered in providing 6/7 of the required volume for the 48 hours5.555556e-4 days 0.0133 hours 7.936508e-5 weeks 1.8264e-5 months allowed by Required Action C.3.

Required Action C.1 requires the combined volume of FOST

No. 21 and an OPERABLE FOST No. 11 to be verified to be greater than 6/7 of the required volume within one hour. Required Action C.3 then requires the volume of FOST No. 21 to be restored to within volume limits within 48 hours5.555556e-4 days 0.0133 hours 7.936508e-5 weeks 1.8264e-5 months .

However, during tornado season, i.e., from April 1 to

September 30, the fuel oil volume of FOST No. 11 is not allowed to be credited and the fuel oil seven day volume of Diesel Fuel Oil B 3.8.3 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.3-6 Revision 2 FOST No. 21 must be restored within two hours as indicated in Required Action C.2. Required Action C.2 is also modified by a Note such that it is only required during the

operation of Unit 2 in MODE s 1, 2, 3, or 4 since the unit is already shutdown if it is in another MODE or condition. An

OPERABLE FOST No. 11 is determined as described above in the discussion for Condition B.

D.1 This Condition is entered as a result of a failure to meet

the acceptance criterion of SR 3.8.3.2. Normally, trending

of particulate levels allows sufficient time to correct high

particulate levels prior to reaching the limit of

acceptability. Poor sample procedures (bottom sampling),

contaminated sampling equipment, and errors in laboratory

analysis can produce failures that do not follow a trend.

Since the presence of particulates does not mean failure of

the fuel oil to burn properly in the diesel engine, and

particulate concentration is unlikely to change

significantly between S R Frequency intervals, and proper engine performance has been recently demonstrated (within

31 days), it is prudent to allow a brief period prior to

declaring the associated DG inoperable. The seven day Completion Time allows for further evaluation, resampling, and re-analysis of the DG fuel oil.

E.1 With the new fuel oil properties defined in the Bases for

SR 3.8.3.2 not within the required limits, a period of

30 days is allowed for restoring the stored fuel oil

properties to within the new fuel oil limits. This period

provides sufficient time to test the stored fuel oil to

determine that the new fuel oil, when mixed with previously

stored fuel oil, remains acceptable, or restore the stored fuel oil properties to within the new fuel oil limits. This restoration may involve feed and bleed procedures, filtering, or combinations of these procedures. Even if a

DG start and load was required during this time interval

, and the fuel oil properties were outside limits, there is a

high likelihood that the DG would still be capable of

performing its intended function.

Diesel Fuel Oil B 3.8.3 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.3-7 Revision 2 F.1 With a Required Action and associated Completion Time not met, or one or more DGs with diesel fuel oil not within

limits for reasons other than addressed by Conditions A

through E, the associated DG may be incapable of performing

its intended function and must be immediately declared inoperable. "Associated DG(s)" are identified in the

Applicability Bases.

SURVEILLANCE SR 3.8.3.1 REQUIREMENTS

This SR provides verification that there is an adequate

inventory of fuel oil in the DG FOSTs to support one unit on accident loads and one unit on shutdown loads for

seven days. The seven day period is sufficient time to place the unit in a safe shutdown condition and to bring in

replenishment fuel from an offsite location.

The 31 day Frequency is adequate to ensure that a sufficient

supply of fuel oil is available, since low level alarms are

provided and unit operators would be aware of any large uses

of fuel oil during this period.

SR 3.8.3.2 The tests listed below are a means of determining whether

new fuel oil is of the appropriate grade (i.e., 2D and 2D

low sulfur) and has not been contaminated with substances

that would have an immediate, detrimental impact on diesel

engine combustion. Note that further references to American Society for Testing Materials (ASTM) 2D fuel oil include both 2D and 2D low sulfur. If results from these tests are

within acceptable limits, the fuel oil may be added to the

storage tanks without concern for contaminating the entire

volume of fuel oil in the storage tanks. These tests are to

be conducted prior to adding the new fuel to the storage

tank(s), but in no case is the time between receipt of new

fuel and conducting the tests to exceed 31 days. The tests, limits, and applicable ASTM Standards are as follows:

a. Sample the new fuel oil in accordance with Reference 3, ASTM D4057-1995;

Diesel Fuel Oil B 3.8.3 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.3-8 Revision 3

b. Verify in accordance with the tests specified in Reference 3, ASTM D975-1996, that the sample has an absolute specific gravity at 60/60°F of 0.8155 and 0.8871, or an American Petroleum Institute gravity at 60°F of 28° and 42°, a kinematic viscosity at 40°C of 1.9 centistokes and 4.1 centistokes, and a flash point 125°F; and c. Verify that the new fuel oil has 0.05% water and sediment (Reference 3, ASTM D975-1996).

Failure to meet any of the above limits is cause for

rejecting the new fuel oil, but does not represent a failure

to meet the LCO concern since the fuel oil is not added to

the storage tanks.

Within 31 days following the initial new fuel oil sample, the fuel oil is analyzed to establish that the other

properties specified in Reference 2, ASTM D975-1996, Table 1, are met for new fuel oil. The 31 day period is

acceptable because the fuel oil properties of interest, even

if they were not within stated limits, would not have an

immediate effect on DG operation. This SR ensures the

availability of high quality fuel oil for the DGs.

Fuel oil degradation during long-term storage shows up as an increase in particulate, due mostly to oxidation. The

presence of particulate does not mean the fuel oil will not

burn properly in a diesel engine. The particulate can cause

fouling of filters and fuel oil injection equipment, however, that can cause engine failure.

Particulate concentrations should be determined by gravimetric analysis (based on ASTM D2276-1989) of total

particulate concentration in the fuel oil and has a limit of

10 mg/l. It is acceptable to obtain a field sample for subsequent laboratory testing in lieu of field testing.

Because the total stored fuel oil volume for DG Nos. 1B, 2A, and 2B is contained in two interconnected tanks, each tank

must be considered and tested separately. There is a

separate FOST for DG No. 1A.

Diesel Fuel Oil B 3.8.3 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.3-9 Revision 2 The Frequency of this test takes into consideration fuel oil degradation trends that indicate that particulate

concentration is unlikely to change significantly between

Frequency intervals.

SR 3.8.3.3 Microbiological fouling is a major cause of fuel oil degradation. There are numerous bacteria that can grow in

fuel oil and cause fouling, but all must have a water

environment in order to survive. Removal of water from the

fuel storage tanks once every 92 days eliminates the

necessary environment for bacterial survival. This is the

most effective means of controlling microbiological fouling.

In addition, it eliminates the potential for water

entrainment in the fuel oil during DG operation. Water may

come from any of several sources, including condensation, ground water, rain water, and contaminated fuel oil, and

from breakdown of the fuel oil by bacteria. Frequent

checking for and removal of accumulated water minimizes

fouling and provides data regarding the watertight integrity

of the fuel oil system. The S R Frequencies are established by Reference

3. This SR is for preventative maintenance.

The presence of water does not necessarily represent failure

of this SR provided the accumulated water is removed during performance of the s urveillance test. REFERENCES 1. UFSAR

2. ASTM Standards

3. Regulatory Guide 1.137 , "Fuel-Oil Systems for Standby Diesel Generators," January 1978

DC Sources-Operating B 3.8.4 B 3.8 ELECTRICAL POWER SYSTEMS B 3.8.4 DC Sources-Operating

BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.4-1 Revision 2 BACKGROUND The station DC sources provide the AC emergency power system with control power. It also provides both motive and control power to selected safety related equipment and

preferred AC vital bus power (via inverters). As required by Reference 1 , Appendix 1C, Criterion 39 , the DC electrical power sources are designed to have sufficient independence, redundancy, and testability to perform their safety

functions, assuming a single failure. The DC sources also

conform to the recommendations of Reference s 2 and 3.

The 125 VDC electrical power sources consist of four independent and redundant safety related Class 1E DC

channels. Each channel consists of one 125 VDC battery, the

associated battery charger for each battery, and all the

associated control equipment and interconnecting cabling.

During normal operation, the 125 VDC load is powered from the battery chargers with the batteries floating on the

system. In cases where momentary loads are greater than the

charger capability, or a loss of normal power to the battery

charger, the DC load is automatically powered from the

station batteries.

The DC channels provide the control power for its associated Class 1E AC power load group, 4.16 kV switchgear, and 480 V

load centers. The DC channels also provide a DC source to

the inverters, which in turn power the AC vital buses.

The DC sources are described in more detail in the Bases for LCO 3.8.9 and for LCO 3.8.10

.

Each battery has adequate storage capacity to carry the required load continuously for at least 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months and to carry

load duty cycle as discussed in Reference 1, Chapter 8.

Each 125 VDC battery is separately housed in a ventilated room apart from its charger and distribution centers. Each

channel is separated physically and electrically from the

other channel to ensure that a single failure in one channel

does not cause a failure in a redundant channel. There is DC Sources-Operating B 3.8.4 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.4-2 Revision 2 no sharing between redundant Class 1E channels, such as batteries, battery chargers, or distribution panels.

The batteries for DC channels are sized to produce required capacity at 80% of nameplate rating, corresponding to

warranted capacity at end of life cycles and the 100% design demand. Battery size is based on 125% of required capacity.

An average voltage of 2.13 V per cell, corresponds to a

total minimum voltage output of 125 V per battery (128 V for

the reserve battery) as discussed in Reference 1, Chapter 8. The criteria for sizing large lead storage batteries are

defined in Reference

4.

Each DC channel has ample power output capacity for the steady state operation of connected loads required during

normal operation, while at the same time maintaining its

battery bank fully charged. Each battery charger also has

sufficient capacity to restore the battery from the design

minimum charge to 95% of its fully charged state within

24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months while supplying normal steady state loads discussed in Reference 1, Chapter 8. APPLICABLE The initial conditions of DBA and transient analyses in SAFETY ANALYSES Reference 1, Chapters 6 and 14 , assume that ESF systems are OPERABLE. The DC channels provide a normal and emergency DC

sources for the DGs, emergency auxiliaries, and control and

switching during all MODE s of operation.

The OPERABILITY of the DC sources is consistent with the initial assumptions of the accident analyses and is based upon meeting the design basis of the unit. This includes maintaining the DC sources OPERABLE during accident

conditions in the event of: a. An assumed loss of all offsite AC power or all onsite AC power; and b. A worst case single failure.

The DC sources satisfy 10 CFR 50.36(c)(2)(ii), Criterion 3.

LCO The DC channels, each channel consisting of one battery, one battery charger, and the corresponding control equipment and

interconnecting cabling supplying power to the associated DC Sources-Operating B 3.8.4 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.4-3 Revision 45 bus, are required to be OPERABLE to ensure the availability of the required power to shut down the reactor and maintain

it in a safe condition after an AOO or a postulated DBA.

Loss of any DC channel does not prevent the minimum safety

function from being performed (Reference 1, Chapter 8).

An OPERABLE DC channel requires the battery and one OPERABLE charger to be operating and connected to the associated DC

bus(es). APPLICABILITY The DC sources are required to be OPERABLE in MODEs 1, 2, 3, and 4 to ensure safe unit operation and to ensure that: a. Acceptable fuel design limits and reactor coolant pressure boundary limits are not exceeded as a result

of AOOs or abnormal transients; and b. Adequate core cooling is provided, and containment integrity and other vital functions are maintained in

the event of a postulated DBA.

The DC sources requirement for MODEs 5 and 6 are addressed in the Bases for LCO 3.8.5.

ACTIONS A.1 Required Action A.1 requires the inoperable battery to be

replaced by the reserve battery within four hours when one

DC channel is inoperable due to an inoperable battery and

the reserve battery is available. The reserve battery is a

qualified battery that can replace and perform the required

function of any inoperable battery. The four hour

Completion Time is acceptable based on the capability of the reserve battery and the time it takes to replace the inoperable battery with the reserve battery while minimizing

the time in this degraded condition.

B.1 Condition B represents one channel with a loss of ability to

completely respond to an event, and a potential loss of

ability to remain energized during normal operation.

Therefore, it is imperative that the operator's attention

focus on stabilizing the unit, minimizing the potential for

complete loss of DC power to the affected channel. The DC Sources-Operating B 3.8.4 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.4-4 Revision 45 2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months limit is consistent with the allowed time for an inoperable DC channel.

If one of the required DC channels is inoperable for reasons other than Condition A (e.g., inoperable battery, inoperable

battery charger(s), or inoperable battery charger and associated inoperable battery), the remaining DC channels have the capacity to support a safe shutdown and to mitigate

an accident condition. Since a subsequent worst case single

failure would, however, result in the further loss of the

125 VDC channels with attendant loss of ESF functions, continued power operation should not exceed 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months . The

2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months Completion Time is based on Reference 5 and reflects

a reasonable time to assess unit status as a function of the

inoperable DC channel and, if the DC channel is not restored

to OPERABLE status, to prepare to effect an orderly and safe

unit shutdown.

C.1 and C.2 If the inoperable DC channel cannot be restored to OPERABLE

status within the required Completion Time, the unit must be

brought to a MODE in which the LCO does not apply. To

achieve this status, the unit must be brought to at least

MODE 3 within 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and to MODE 5 within 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months . The

allowed Completion Times are reasonable, based on operating

experience, to reach the required unit conditions from full

power conditions in an orderly manner and without

challenging unit systems. The Completion Time to bring the

unit to MODE 5 is consistent with the time required in Reference 5.

SURVEILLANCE SR 3.8.4.1 REQUIREMENTS Verifying battery terminal voltage while on float charge helps to ensure the effectiveness of the charging system and

the ability of the batteries to perform their intended

function. Float charge is the condition in which the

charger is supplying connected loads and the continuous

charge required to overcome the internal losses of a battery

and maintain the battery in a fully charged state. The

voltage requirements are based on the nominal design voltage

of the battery (2.13 V per cell average) and are consistent

with Reference 6 and the initial state of charge conditions DC Sources-Operating B 3.8.4 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.4-5 Revision 45 assumed in the battery sizing calculations. The 7 day Frequency is conservative when compared with manufacturer

recommendations and Reference 6.

SR 3.8.4.2 Visual inspection to detect corrosion of the battery cells and connections, or measurement of the resistance of each cell to cell and terminal connection, provides an indication

of physical damage or abnormal deterioration that could

potentially degrade battery performance.

The limits established for this SR must be no more than 20%

above the resistance as measured during installation or not

above the ceiling value established by the manufacturer.

The SR Frequency for these inspections, which can detect conditions that can cause power losses due to resistance

heating, is 92 days. This Frequency is considered

acceptable based on operating experience related to

detecting corrosion trends.

SR 3.8.4.3 Visual inspection of the battery cells, cell plates, and

battery racks provides an indication of physical damage or

abnormal deterioration that could potentially degrade

battery performance.

The presence of physical damage or deterioration does not necessarily represent a failure of this SR, provided an

evaluation determines that the physical damage or

deterioration does not affect the OPERABILITY of the

battery (its ability to perform its design function).

The 18 month Frequency is based on engineering judgment.

Operating experience has shown that these components usually

pass the SR when performed at the 18 month Frequency.

Therefore, the Frequency was concluded to be acceptable from

a reliability standpoint.

SR 3.8.4.4 and SR 3.8.4.5 Visual inspection and resistance measurements of cell to

cell and terminal connections provide an indication of DC Sources-Operating B 3.8.4 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.4-6 Revision 45 physical damage or abnormal deterioration that could indicate degraded battery condition. The anti-corrosion

material is used to help ensure good electrical connections

and to reduce terminal deterioration. The visual inspection

for corrosion is not intended to require removal of and

inspection under each terminal connection. The removal of visible corrosion is a preventive maintenance SR. The presence of visible corrosion does not necessarily represent

a failure of this SR provided visible corrosion is removed

during performance of SR 3.8.4.4.

The connection resistance limits for SR 3.8.4.5 shall be no more than 20% above the resistance as measured during

installation, or not above the ceiling value established by

the manufacturer.

The 18 month Frequency for these SRs is based on engineering judgment. Operating experience has shown that these

components usually pass the SRs when performed at the

18 month Frequency. Therefore, the Frequency was concluded

to be acceptable from a reliability standpoint.

SR 3.8.4.6 This SR requires that each battery charger be capable of supplying 400 amps and 125 V for 30 minutes. These requirements are based on the output rating of the chargers (Reference 1, Chapter 8). According to Reference 7, the

battery charger supply is required to be based on the

largest combined demands of the various steady state loads

and the charging capacity to restore the battery from the

design minimum charge state to the fully charged state, irrespective of the status of the unit during these demand

occurrences. The minimum required amperes and duration

ensures that these requirements can be satisfied. The test

is performed while supplying normal DC loads or an equivalent or greater dummy load.

The SR Frequency is acceptable, given the unit conditions required to perform the test and the other administrative

controls existing to ensure adequate charger performance

during these 24 month intervals. In addition, this

Frequency is intended to be consistent with expected fuel

cycle lengths.

DC Sources-Operating B 3.8.4 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.4-7 Revision 45 SR 3.8.4.7 A battery service test is a special test of battery

capability, as found and with the associated battery charger

disconnected, to satisfy the design requirements (battery

duty cycle) of the DC source. The test duration must be 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months and battery terminal voltage must be maintained 105 volts during the test. The discharge rate and test length should correspond to the design accident load (duty) cycle requirements as specified in Reference 1, Chapter 8.

A dummy load simulating the emergency loads of the design

duty cycle may be used in lieu of the actual emergency

loads.

The SR Frequency of 24 months is consistent with expected fuel cycle lengths.

This SR is modified by a Note. The Note allows the performance of a modified performance discharge test in lieu

of a service test. This substitution is acceptable because

a modified performance discharge test represents a more

severe test of battery capacity than SR 3.8.4.7.

SR 3.8.4.8 A battery performance discharge test is a test of constant

current capacity of a battery after having been in service, to detect any change in the capacity determined by the

acceptance test. The test is intended to determine overall

battery degradation due to age and usage.

A battery modified performance discharge test is a simulated duty cycle consisting of just two rates; the one minute rate

published for the battery or the largest current load of the

duty cycle, followed by the test rate employed for the

performance discharge test, both of which envelope the duty cycle of the service test. Since the ampere-hours removed by a rated one minute discharge represents a very small

portion of the battery capacity, the test rate can be

changed to that for the performance test without

compromising the results of the performance discharge test.

The battery terminal voltage for the modified performance

discharge test should remain above the minimum battery DC Sources-Operating B 3.8.4 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.4-8 Revision 45 terminal voltage specified in the battery performance discharge test for the duration of time equal to that of the

performance discharge test.

A modified performance discharge test is a test of the battery capacity and its ability to provide a high rate, short duration load (usually the highest rate of the duty cycle). This will often confirm the battery's ability to

meet the critical period of the load duty cycle, in addition

to determining its percentage of rated capacity. Initial

conditions for the modified performance discharge test

should be identical to those specified for a service test.

Either the battery performance discharge test or the

modified performance discharge test is acceptable for

satisfying SR 3.8.4.8; however, only the modified

performance discharge test may be used to satisfy SR 3.8.4.8

while satisfying the requirements of SR 3.8.4.7 at the same

time.

The acceptance criteria for this SR are consistent with References 6 and 4. These references recommend that the

battery be replaced if its capacity is below 80% of the

manufacturer rating. A capacity of 80% shows that the

battery rate of deterioration is increasing, even if there

is ample capacity to meet the load requirements.

The SR Frequency for this test is normally 60 months. If the battery shows degradation, or if the battery has reached

85% of its expected life and capacity is < 100% of the

manufacturer's rating, the SR Frequency is reduced to

12 months. However, if the battery shows no degradation but

has reached 85% of its expected life, the SR Frequency is

only reduced to 24 months for batteries that retain capacity 100% of the manufacturer's rating. Degradation is indicated, according to Reference 6, when the battery capacity drops by more than 10% relative to its capacity on the previous performance test or when it is 10% below the manufacturer's rating. These Frequencies are consistent with the recommendations in Reference 6.

DC Sources-Operating B 3.8.4 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.4-9 Revision 45 REFERENCES 1. UFSAR

2. Safety Guide 6, Revision 0, "Assumptions Used for Evaluating the Potential Radiological Consequences of a Steam Line Break Accident for Boiling Water Reactors,"

March 1971

3. IEEE Standard 308-1978, "IEEE Standard Criteria for Class 1E Power Systems for Nuclear Power Generating

Stations" 4. IEEE Standard 485-1983, "Recommended Practice for Sizing Large Lead Storage Batteries for Generating

Stations and Substations (ANSI)," June 1983

5. Regulatory Guide 1.93, "Availability of Electric Power Sources," December 1974 6. IEEE Standard 450-1995, "IEEE Recommended Practice for Maintenance, Testing, and Replacement of Vented Lead-

Acid Batteries for Stationary Applications," May 1995 7. Regulatory Guide 1.32, Revision 2, "Criteria for Safety-Related Electric Power Systems for Nuclear Power Plants," February 1977 DC Sources-Shutdown B 3.8.5 B 3.8 ELECTRICAL POWER SYSTEMS B 3.8.5 DC Sources-Shutdown

BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.5-1 Revision 2 BACKGROUND A description of the DC sources is provided in the Bases for LCO 3.8.4. APPLICABLE The initial conditions of DBA; and transient analyses in SAFETY ANALYSES Reference 1 , Chapters 6 and 14, assume that ESF systems are OPERABLE. The DC sources provide normal and emergency DC

for the DG s, emergency auxiliaries, and control and switching during all MODE s of operation.

The OPERABILITY of the DC subsystems is consistent with the

initial assumptions of the accident analyses and the

requirements for the supported systems' OPERABILITY.

The OPERABILITY of the minimum DC sources during MODE s 5 and 6 and during movement of irradiated fuel assemblies

ensures that:

a. The unit can be maintained in the shutdown or refueling condition for extended periods;

b. Sufficient instrumentation and control capability is available for monitoring and maintaining the unit

status; and c. Adequate DC sources are provided to mitigate events postulated during shutdown, such as a fuel handling

accident.

The DC sources satisfy 10 CFR 50.36(c)(2)(ii), Criterion 3.

LCO The DC channels, each channel consisting of one battery, one

battery charger, and the corresponding control equipment and

interconnecting cabling within the channel, are required to

be OPERABLE to support required trains of distribution

systems required OPERABLE by LCO 3.8.10

. This ensures the availability of sufficient DC sources to operate the unit in

a safe manner and to mitigate the consequences of postulated events during shutdown (e.g., fuel handling accidents).

DC Sources-Shutdown B 3.8.5 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.5-2 Revision 29 APPLICABILITY The DC sources required to be OPERABLE in MODEs 5 and 6, and during movement of irradiated fuel assemblies provide assurance that:

a. Required features needed to mitigate a fuel handling accident are available;

b. Required features necessary to mitigate the effects of events that can lead to core damage during shutdown are

available; and

c. Instrumentation and control capability is available for monitoring and maintaining the unit in a cold shutdown

condition or refueling condition.

The DC channel requirements for MODEs 1, 2, 3, and 4 are covered in LCO 3.8.4.

ACTIONS Limiting Condition for Operation 3.0.3 is not applicable while in MODE 5 or 6. However, since irradiated fuel

assembly movement can occur in MODE 1, 2, 3, or 4, the

ACTIONS have been modified by a Note stating that LCO 3.0.3

is not applicable. If moving irradiated fuel assemblies

while in MODE 5 or 6, LCO 3.0.3 would not specify any

action. If moving irradiated fuel assemblies while in MODE

1, 2, 3, or 4, the fuel movement is independent of reactor

operations. Therefore, in either case, the inability to

suspend movement of irradiated fuel assemblies would not be

sufficient reason to require a reactor shutdown.

The ACTIONS have been modified by a second Note stating that performance of REQUIRED ACTIONS shall not preclude

completion of actions to establish a safe conservative position. This clarification is provided to avoid stopping movement of irradiated fuel assemblies while in a non-

conservative position based on compliance with the REQUIRED

ACTIONS.

A.1, A.2.1, A.2.2, and A.2.3 If two trains are required per LCO 3.8.10, the remaining

train with DC power available may be capable of supporting

sufficient systems to allow continuation of movement of irradiated fuel assemblies. By allowing the option to declare required features inoperable with the associated DC DC Sources-Shutdown B 3.8.5 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.5-3 Revision 29 power source(s) inoperable, appropriate restrictions will be implemented in accordance with the affected required

features LCO ACTIONS. In many instances, this option may

involve undesired administrative efforts. Therefore, the

allowance for sufficiently conservative actions is made (i.e., to suspend movement of irradiated fuel assemblies and operations involving positive reactivity additions). The

Required Action to suspend positive reactivity additions

does not preclude actions to maintain or increase reactor

vessel inventory, provided the required SDM is maintained.

Suspension of these activities shall not preclude completion

of actions to establish a safe conservative condition.

These actions minimize probability of the occurrence of

postulated events. It is further required to immediately

initiate action to restore the required DC channels and to

continue this action until restoration is accomplished in

order to provide the necessary DC source to the unit safety

systems.

The Completion Time of immediately is consistent with the required times for actions requiring prompt attention. The

restoration of the required DC channels should be completed

as quickly as possible in order to minimize the time during

which the unit safety systems may be without sufficient power. SURVEILLANCE SR 3.8.5.1 REQUIREMENTS

Surveillance Requirement 3.8.5.1 states that surveillance tests required by SR 3.8.4.1 through SR 3.8.4.8 are applicable in these MODEs. See the corresponding Bases for

LCO 3.8.4 for a discussion of each SR.

This SR is modified by a Note. The reason for the Note is

to preclude requiring the OPERABLE DC sources from being

discharged below their capability to provide the required

power supply or otherwise rendered inoperable during the

performance of SRs. It is the intent that these SRs must

still be capable of being met, but actual performance is not required.

DC Sources-Shutdown B 3.8.5 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.5-4 Revision 2 REFERENCES 1. UFSAR

Battery Cell Parameters B 3.8.6 B 3.8 ELECTRICAL POWER SYSTEMS B 3.8.6 Battery Cell Parameters

BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.6-1 Revision 2 BACKGROUND This LCO delineates the limits on electrolyte temperature, level, individual cell float voltage (ICV), and specific gravity for the DC power source batteries. A discussion of

these batteries and their OPERABILITY requirements is provided in the Bases for LCO 3.8.4 and LCO 3.8.5

. APPLICABLE The initial conditions of DBA and transient analyses in SAFETY ANALYSES Reference 1 , Chapters 6 and 14 , assume ESF systems are OPERABLE. The DC sources provide normal and emergency DC

electrical power for the DG s, emergency auxiliaries, and control and switching during all MODE s of operation.

The OPERABILITY of the DC channels is consistent with the

initial assumptions of the accident analyses and is based

upon meeting the design basis of the unit, as discussed in

the Bases for LCO 3.8.4 and LCO 3.8.5.

Battery cell parameters satisfy Criterion 3 of the NRC Policy Statement.

LCO Battery cell parameters must remain within acceptable limits

to ensure availability of the required DC power to shut down

the reactor and maintain it in a safe condition after an AOO or a postulated DBA. Electrolyte limits are conservatively

established, allowing continued DC electrical system function even with Category A or B limits not met.

APPLICABILITY The battery parameters are required solely for the support of the associated DC electrical power subsystems.

Therefore, battery electrolyte is only required when the

DC power source is required to be OPERABLE. Refer to the

Applicability discussion in the Bases for LCO 3.8.4 and LCO 3.8.5.

ACTIONS The Actions Table is modified by a Note which indicates that separate Condition entry is allowed for each battery. This

is acceptable, since the Required Actions for each Condition

provide appropriate compensatory actions for each inoperable

DC channel. Complying with the Required Actions for one Battery Cell Parameters B 3.8.6 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.6-2 Revision 2 inoperable DC channel may allow for continued operation, and subsequent inoperable DC subsystem(s) are governed by

separate Condition entry and application of associated

Required Actions.

A.1, A.2.1, A.2.2, and A.3

With parameters of one or more cells

, in one or more batteries , not within limits (i.e., Category A limits not met or Category B limits not met) but within Category C

limits specified in Table 3.8.6-1, the battery is degraded

but there is still sufficient capacity to perform the

intended function. Therefore, the affected battery is not

required to be considered inoperable solely as a result of

Category A or B limits not met, and continued operation is

permitted for a limited period.

The pilot cell electrolyte level and ICV are required to be verified to meet the Category C limits within one hour (Required Action A.1). This check will provide a quick

indication of the status of the remainder of the battery

cells. One hour provides time to inspect the electrolyte

level and to confirm the ICV of the pilot cells. One hour

is considered a reasonable amount of time to perform the

required verification.

Verification that the Category C limits are met (Required Action A.2) provides assurance that during the time needed

to restore the parameters to the Category A and B limits, the battery will still be capable of performing its intended

function. A period of 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months is allowed to complete the

initial verification because specific gravity measurements

must be obtained for each connected cell. Taking into

consideration both the time required to perform the required verification and the assurance that the battery cell parameters are not severely degraded, this time is

considered reasonable. The verification is repeated at

seven day intervals until the parameters are restored to Category A and B limits. This periodic verification is

consistent with the normal Frequency of pilot cell

Surveillances.

Battery Cell Parameters B 3.8.6 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.6-3 Revision 2 Continued operation prior to declaring the affected batteries inoperable is permitted for 31 days before battery

cell parameters must be restored to within Category A and B

limits. With the consideration that, while battery capacity

is degraded, sufficient capacity exists to perform the

intended function and to allow time to fully restore the battery cell parameters to normal limits, this time is acceptable prior to declaring the battery inoperable.

B.1 With one or more batteries with one or more battery cell

parameters outside the Category C limit for any connected

cell, sufficient capacity to supply the maximum expected

load requirement is not assured and the corresponding DC

channel must be declared inoperable. Additionally, other

potentially extreme conditions, such as any Required Action

of Condition A and associated Completion Time not met

, or average electrolyte temperature of representative cells 69 F, are also cause for immediately declaring the associated DC channel inoperable.

SURVEILLANCE SR 3.8.6.1 REQUIREMENTS

This SR verifies that Category A battery cell parameters are

consistent with Reference 2 , which recommends regular battery inspections (at least one per month) including

voltage, specific gravity, and electrolyte temperature of

pilot cells.

SR 3.8.6.2 The quarterly inspection of specific gravity and voltage is

consistent with Reference

2.

SR 3.8.6.3 This Surveillance verification that the average temperature of representative cells is 69 F is consistent with a recommendation of Reference 2 , which states that the temperature of electrolytes in representative cells should be determined on a quarterly basis. The temperature is also

high enough to supply the required capacity.

Battery Cell Parameters B 3.8.6 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.6-4 Revision 2 Lower than normal temperatures act to inhibit or reduce

battery capacity. This SR ensures that the operating

temperatures remain within an acceptable operating range.

This limit is based on manufacturer recommendations.

Table 3.8.6-1 This Table delineates the limits on electrolyte level, ICV, and specific gravity for three different categories. The

meaning of each category is discussed below.

Category A defines the normal parameter limit for each

designated pilot cell in each battery. The cells selected

as pilot cells are those whose temperature, voltage

, and electrolyte specific gravity approximate the state of charge

of the entire battery.

The Category A limits specified for electrolyte level are

based on manufacturer recommendations and are consistent

with the guidance in Reference 2 , with the extra 1/4 inch allowance above the high water level indication for

operating margin to account for temperatures and charge

effects. In addition to this allowance, Footnote (a) to

Table 3.8.6-1 permits the electrolyte level to be

temporarily above the specified maximum level during and

following equalizing charge (i.e., for up to seven days following the completion of an equalize charge), provided it

is not overflowing. These limits ensure that the plates

suffer no physical damage, and that adequate electron

transfer capability is maintained in the event of transient

conditions.

Reference 2 recommends that electrolyte level readings should be made only after the battery has been at

float charge for at least 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months .

The Category A limit specified for ICV is 2.13 V per cell. This value is based on a recommendation of Reference 2 , which states that prolonged operation of cells 2.13 V can reduce the life expectancy of cells.

The Category A limit specified for specific gravity for each pilot cell is 1.200 (0.015 below the manufacturer fully charged nominal specific gravity or a battery charging Battery Cell Parameters B 3.8.6 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.6-5 Revision 2 current that had stabilized at a low value). This value is characteristic of a charged cell with adequate capacity.

According to Reference 2 , the specific gravity readings are based on a temperature of 77 F (25 C) and full electrolyte

level. The specific gravity readings are corrected for actual electrolyte temperature and level. For each 3 F (1.67 C) above 77 F (25 C), 1 point (0.001) is added to the reading;

1 point is subtracted for each 3 F below 77 F. The specific gravity of the electrolyte in a cell increases with a loss

of water due to electrolysis or evaporation.

Category B defines the normal parameter limits for each

connected cell. The term "connected cell" excludes any

battery cell that may be jumpered out.

The Category B limits specified for electrolyte level and

ICV are the same as those specified for Category A and have

been discussed above. The Category B limit specified for specific gravity for each connected cell is 1.195 (0.020 below the manufacturer fully charged, nominal specific

gravity) with the average of all connected cells 1.205 (0.010 below the manufacturer fully charged, nominal specific gravity). These values are based on manufacturer's

recommendations. The minimum specific gravity value

required for each cell ensures a cell with a marginal or

unacceptable specific gravity is not masked by averaging

cells having higher specific gravities.

Category C defines the limit for each connected cell. These

values, although reduced, provide assurance that sufficient

capacity exists to perform the intended function and

maintain a margin of safety. When any battery parameter is

outside the Category C limit, the assurance of sufficient capability described above no longer exists and the battery must be declared inoperable.

The Category C limit specified for electrolyte level (above

the top of the plates and not overflowing) ensures that the

plates suffer no physical damage and maintain adequate

electron transfer capability. The Category C limit for ICV

is derived from Reference 2 recommendations , which states Battery Cell Parameters B 3.8.6 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.6-6 Revision 2 that a cell voltage of 2.07 V or below, under float conditions and not caused by elevated temperature of the

cell, indicates internal cell problems and may require cell

replacement.

The Category C limit of average specific gravity 1.195 is based on manufacturer recommendations (0.020 below the manufacturer recommended fully charged, nominal specific

gravity). In addition to that limit, it is required that

the specific gravity for each connected cell must be no less

than 0.020 below the average of all connected cells. This

limit ensures that a cell with a marginal or unacceptable

specific gravity is not masked by averaging with cells

having higher specific gravities.

The footnotes to Table 3.8.6-1 are applicable to Category A, B, and C specific gravity. Footnote (b) to Table 3.8.6-1

requires the above mentioned correction for electrolyte

level and temperature, with the exception that level

correction is not required when battery charging current is 1 amp on float charge. This current provides, in general, an indication of acceptable overall battery condition.

Because of specific gravity gradients that are produced during the recharging process, delays of several days may

occur while waiting for the specific gravity to stabilize.

A stabilized charging current is an acceptable alternative

to specific gravity measurement for determining the state of

charge. This phenomenon is discussed in Reference

2. Footnote (c) to Table 3.8.6-1 allows the float charge

current to be used as an alternate to specific gravity for

up to seven days following a battery equalizing recharge.

Within seven days, each connected cell's specific gravity must be measured to confirm the state of charge. Following a minor battery recharge (such as equalizing charge that does not follow a deep discharge) specific gravity gradients

are not significant, and confirming measurements may be made in less than seven days.

Battery Cell Parameters B 3.8.6 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.6-7 Revision 2 REFERENCES 1. UFSAR

2. IEEE Standard

-450-1995 , "IEEE Recommended Practice for Maintenance, Testing, and Replacement Vented Lead-Acid Batteries for Stationary Applications," May 1995

Inverters-Operating B 3.8.7 B 3.8 ELECTRICAL POWER SYSTEMS B 3.8.7 Inverters-Operating

BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.7-1 Revision 2 BACKGROUND The inverters are the preferred source of power for the AC vital buses

, because of the stability and reliability they achieve. The function of the inverter is to provide AC electrical power to the vital buses. Each inverter has two built-in independent inverters, either one of which can serve as the preferred source of power. In these dual

inverters, 120 volt AC power output can be manually switched

from one side to the other side. The inverters can be powered from the DC b us which is energized from the station battery and/or battery chargers. The station battery and

the inverters provides an uninterruptible power source for

the instrumentation and controls for the Reactor Protective

System (RPS) and the ESFAS. Specific details on inverters and their operating characteristics are found in Reference 1 , Chapter 8.

APPLICABLE The initial conditions of DBA and transient analyses in SAFETY ANALYSES Reference 1, Chapters 6 and 14 , assume ESF systems are OPERABLE. The inverters are designed to provide the

required capacity, capability, redundancy, and reliability

to ensure the availability of necessary power to the RPS and

ESFAS instrumentation and controls so that the fuel, RCS , and containment design limits are not exceeded. These

limits are discussed in more detail in the Bases for

Sections 3.2 , 3.4 , and 3.6.

The OPERABILITY of the inverters is consistent with the

initial assumptions of the accident analyses and is based on meeting the design basis of the unit. This includes maintaining required AC vital buses OPERABLE during accident

conditions in the event of:

a. An assumed loss of all offsite AC electrical power or all onsite AC electrical power; and

b. A worst case single failure.

Inverters are a part of the distribution system and, as such, satisfy 10 CFR 50.36(c)(2)(ii), Criterion 3.

Inverters-Operating B 3.8.7 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.7-2 Revision 2 LCO The LCO requires four inverters to be operable, one inverter per AC vital bus. Each AC vital bus can receive power from

either side of the dual inverter. Each side of the dual

inverter is fully rated

, to power the AC vital bus.

Therefore, only one side of each dual inverter is required

for the inverter to be considered OPERABLE.

The inverters ensure the availability of AC electrical power

for the systems instrumentation required to shut down the

reactor and maintain it in a safe condition after an AOO or a postulated DBA.

Maintaining the required inverters OPERABLE ensures that the

redundancy incorporated into the design of the RPS and ESFAS

instrumentation and controls

, is maintained. The four required inverters per unit ensure an uninterruptible supply

of AC electrical power to each of the units AC vital buses

even if the 4.16 kV safety buses are de-energized.

OPERABLE inverters require the associated vital bus to be

powered by either side of the dual inverter with output

voltage within tolerances, and power input to the inverter

from a 125 VDC station battery. Alternatively, power supply

may be from the battery charger as long as the station

battery is available as the uninterruptible power supply.

APPLICABILITY The inverters are required to be OPERABLE in MODE s 1, 2, 3, and 4 to ensure that:

a. Acceptable fuel design limits and reactor coolant pressure boundary limits are not exceeded as a result of AOOs or abnormal transients; and b. Adequate core cooling is provided, and containment OPERABILITY and other vital functions are maintained in the event of a postulated DBA.

Inverter requirements for MODE s 5 and 6 are covered in the Bases for LCO 3.8.8

.

ACTIONS A.1 With a required inverter inoperable, its associated AC vital

bus becomes inoperable until it is manually re-energized Inverters-Operating B 3.8.7 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.7-3 Revision 2 from its 120 VAC bus powered by an ESF m otor c ontrol c enter through a regulating transformer.

Required Action A.1 is modified by a Note, which states to

enter the applicable conditions and Required Actions of

LCO 3.8.9 , when Condition A is entered with one AC vital bus de-energized. This ensures the vital bus is re-energized

within two hours.

Required Action A.1 allows 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months to fix the inoperable

inverter and return it to service. The 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months limit is

based upon engineering judgment, taking into consideration

the time required to repair an inverter and the additional

risk to which the unit is exposed because of the inverter

inoperability. This has to be balanced against the risk of

an immediate shutdown, along with the potential challenges

to safety systems such a shutdown might entail. When the AC

vital bus is powered from its constant voltage source, it is

relying upon interruptible AC electrical power sources (offsite and onsite). The uninterruptible inverter source

to the AC vital buses is the preferred source for powering

instrumentation trip setpoint devices.

B.1 and B.2 If the inoperable devices or components cannot be restored

to OPERABLE status within the required Completion Time, the

unit must be brought to a MODE in which the LCO does not

apply. To achieve this status, the unit must be brought to

at least MODE 3 within six hours and to MODE 5 within 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months . The allowed Completion Times are reasonable, based on operating experience, to reach the required unit

conditions from full power conditions in an orderly manner and without challenging unit systems.

SURVEILLANCE SR 3.8.7.1 REQUIREMENTS

This S R verifies that the inverters are functioning properly with all required circuit breakers closed and AC vital buses

energized from the inverter. The verification of proper

voltage output ensures that the required power is readily

available for the instrumentation of the RPS and ESFAS

connected to the AC vital buses. The seven day Frequency Inverters-Operating B 3.8.7 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.7-4 Revision 2 takes into account the redundant capability of the inverters and other indications available in the C ontrol R oom that alert the operator to inverter malfunctions.

REFERENCES 1. UFSAR

Inverters-Shutdown B 3.8.8 B 3.8 ELECTRICAL POWER SYSTEMS B 3.8.8 Inverters-Shutdown

BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.8-1 Revision 2 BACKGROUND A description of the inverters is provided in the Bases for LCO 3.8.7. APPLICABLE The initial conditions of DBA and transient analyses in SAFETY ANALYSES Reference 1 , Chapters 6 and 14 , assume ESF systems are OPERABLE. The DC to AC inverters are designed to provide

the required capacity, capability, redundancy, and

reliability to ensure the availability of necessary power to

the RPS and ESFAS instrumentation and controls so that the fuel, RCS , and containment design limits are not exceeded.

The OPERABILITY of the inverters is consistent with the

initial assumptions of the accident analyses and the

requirements for the supported systems' OPERABILITY.

The OPERABILITY of the minimum inverters to each AC vital

bus during MODE s 5 and 6 ensures that:

a. The unit can be maintained in the shutdown or refueling condition for extended periods;

b. Sufficient instrumentation and control capability is available for monitoring and maintaining the unit

status; and

c. Adequate power is available to mitigate events postulated during shutdown, such as a fuel handling

accident.

The inverters were previously identified as part of the distribution system and, as such, satisfy 10 CFR 50.36(c)(2)(ii), Criterion 3.

LCO The inverters ensure the availability of electrical power for the instrumentation for systems required to shut down

the reactor and maintain it in a safe condition after an AOO or a postulated DBA. The battery powered inverters provide

uninterruptible supply of AC electrical power to the AC

vital buses even if the 4.16 kV safety buses are

de-energized. OPERABILITY of the inverters requires that

the vital bus be powered by the inverter. This ensures the Inverters-Shutdown B 3.8.8 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.8-2 Revision 29 availability of sufficient inverter power sources to operate the unit in a safe manner and to mitigate the consequences

of postulated events during shutdown (e.g., fuel handling accidents).

APPLICABILITY The inverters required to be OPERABLE in MODEs 5 and 6 and during movement of irradiated fuel assemblies provide

assurance that:

a. Systems to provide adequate coolant inventory makeup are available for the irradiated fuel in the core; b. Systems needed to mitigate a fuel handling accident are available; c. Systems necessary to mitigate the effects of events that can lead to core damage during shutdown are

available; and d. Instrumentation and control capability is available for monitoring and maintaining the unit in a cold shutdown

condition or refueling condition.

Inverter requirements for MODEs 1, 2, 3, and 4 are covered in LCO 3.8.7.

ACTIONS Limiting Condition for Operation 3.0.3 is not applicable while in MODEs 5 or 6. However, since irradiated fuel

assembly movement can occur in MODEs 1, 2, 3, or 4, the ACTIONS have been modified by a Note stating that LCO 3.0.3 is not applicable. If moving irradiated fuel assemblies

while in MODEs 5 or 6, LCO 3.0.3 would not specify any

action. If moving irradiated fuel assemblies while in

MODEs 1, 2, 3, or 4, the fuel movement is independent of

reactor operations. Therefore, in either case, inability to

suspend movement of irradiated fuel assemblies would not be

sufficient reason to require a reactor shutdown.

A.1, A.2.1, A.2.2, and A.2.3 If two trains are required by LCO 3.8.10, the remaining

OPERABLE inverters may be capable of supporting sufficient

required features to allow continuation of movement of irradiated fuel assemblies , operations with a potential for draining the reactor vessel, and operations with a potential

for positive reactivity additions. By the allowance of the Inverters-Shutdown B 3.8.8 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.8-3 Revision 29 option to declare required features inoperable with the associated inverter(s) inoperable, appropriate restrictions

will be implemented in accordance with the affected required

features LCOs' Required Actions. In many instances, this

option may involve undesired administrative efforts. It is

therefore required to suspend movement of irradiated fuel assemblies, and operations involving positive reactivity

additions that could result in loss of the required SDM (MODE 5) or boron concentration (MODE 6). Suspending

positive reactivity additions that could result in failure

to meet the minimum SDM or boron concentration limit is

required to assure continued safe operation. Introduction

of coolant inventory must be from sources that have a boron

concentration greater than that required in the RCS for the

minimum SDM or refueling boron concentration. This may

result in an overall reduction in RCS boron concentration, but provides an acceptable margin to maintaining subcritical

operation. Introduction of temperature changes including

temperature increases when operating with a positive MTC

must also be evaluated to ensure they do not result in a

loss of the required SDM.

Suspension of these activities shall not preclude completion of actions to establish a safe conservative condition.

These actions minimize the probability of the occurrence of

postulated events. It is further required to immediately

initiate action to restore the required inverters and to

continue this action until restoration is accomplished in

order to provide the necessary inverter power to the unit

safety systems.

The Completion Time of immediately is consistent with the required times for actions requiring prompt attention. The

restoration of the required inverters should be completed as quickly as possible in order to minimize the time the unit safety systems may be without power or powered from a constant voltage source transformer.

SURVEILLANCE SR 3.8.8.1 REQUIREMENTS

This SR verifies that the inverters are functioning properly

with all required circuit breakers closed and AC vital buses

energized from the inverter. The verification of proper Inverters-Shutdown B 3.8.8 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.8-4 Revision 19 voltage output ensures that the required power is readily available for the instrumentation connected to the AC vital

buses. The seven day Frequency takes into account the

redundant capability of the inverters and other indications

available in the Control Room that alert the operator to inverter malfunctions.

REFERENCES 1. UFSAR Distribution Systems-Operating B 3.8.9 B 3.8 ELECTRICAL POWER SYSTEMS B 3.8.9 Distribution Systems-Operating

BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.9-1 Revision 5 BACKGROUND The onsite Class 1E AC, DC, and AC vital bus Electrical Power Distribution Systems are divided into two redundant and independent AC electrical power distribution subsystems

and four independent and redundant DC and AC vital bus electrical power distribution subsystems (Reference 1, Chapter 8).

The AC primary Electrical Power Distribution System consists

of two 4.16 kV ESF buses, each having at least one separate

and independent offsite source of power as well as a

dedicated onsite DG source. Each 4.16 kV ESF bus is

normally connected to a preferred offsite source. After a

loss of the preferred offsite power source to a 4.16 kV ESF

bus, the onsite emergency DG supplies power to the 4.16 kV

ESF bus. Control power for the 4.16 kV breakers is supplied

from the Class 1E batteries. Additional description of this

system may be found in the Bases for LCOs 3.8.1 and 3.8.4.

The 480 V system include the safety-related load centers, motor control centers, and distribution panels shown in

Table B 3.8.9-1.

The 120 VAC vital buses are divided into four independent and isolated subsystems and are normally supplied from an

inverter. The alternate power supply for the vital buses

are non-Class 1E 120 VAC Buses fed from a Class 1E ESF motor

control center through the regulating transformer, and its

use is governed by LCO 3.8.7. Each constant voltage source

transformer is powered from a Class 1E AC bus.

There are four independent 125 VDC electrical power distribution subsystems.

The list of all required Distribution Systems-Operating is presented in Table B 3.8.9-1.

APPLICABLE The initial conditions of DBA and transient analyses in SAFETY ANALYSES Reference 1, Chapters 6 and 14, assume ESF systems are OPERABLE. The AC, DC, and AC vital bus Electrical Power

Distribution Systems are designed to provide sufficient Distribution Systems-Operating B 3.8.9 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.9-2 Revision 2 capacity, capability, redundancy, and reliability to ensure the availability of necessary power to ESF systems so that

the fuel, RCS , and containment design limits are not exceeded. These limits are discussed in more detail in the

Bases for Section s 3.2, 3.4, and 3.6. The OPERABILITY of the AC, DC, and AC vital bus Electrical Power Distribution Systems is consistent with the initial assumptions of the accident analyses and is based upon

meeting the design basis of the unit. This includes

maintaining power distribution systems OPERABLE during

accident conditions in the event of:

a. An assumed loss of all offsite power or all onsite AC electrical power; and

b. A worst case single failure.

The distribution systems satisfy 10 CFR 50.36(c)(2)(ii), Criterion 3.

LCO The required electrical power distribution subsystems listed

in Table B 3.8.9-1 ensure the availability of AC, DC, and AC

vital bus electrical supply for the systems required to shut

down the reactor and maintain it in a safe condition after

an AOO or a postulated DBA. The AC, DC, and AC vital bus electrical power distribution subsystems are required to be

OPERABLE.

Maintaining the AC, DC, and AC vital bus electrical power

distribution subsystems OPERABLE ensures that the redundancy

incorporated into the design of ESF is not defeated.

Therefore, a single failure within any system or within the electrical power distribution subsystems will not prevent

safe shutdown of the reactor.

OPERABLE AC electrical power distribution subsystems require

the associated buses, load centers, motor control centers, and distribution panels to be energized to their proper

voltages. OPERABLE DC electrical power distribution

subsystems require the associated buses to be energized to

their proper voltage from either the associated battery or

charger. OPERABLE vital bus electrical distribution Distribution Systems-Operating B 3.8.9 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.9-3 Revision 2 subsystems require the associated buses to be energized to their proper voltage.

In addition, tie breakers between redundant safety

-related AC, DC, and AC vital bus distribution subsystems, if they

exist, must be open. This prevents any electrical malfunction in any distribution subsystem from propagating to the redundant subsystem, which could cause the failure of

a redundant subsystem and a loss of essential safety

function(s). If any tie breakers are closed, the affected

redundant electrical distribution subsystems are considered

inoperable. This applies to the onsite, safety

-related redundant electrical power distribution subsystems.

APPLICABILITY The electrical distribution subsystems are required to be OPERABLE in MODE s 1, 2, 3, and 4 to ensure that:

a. Acceptable fuel design limits and reactor coolant pressure boundary limits are not exceeded as a result

of AOOs or abnormal transients; and

b. Adequate core cooling is provided, and C ontainment OPERABILITY and other vital functions are maintained in

the event of a postulated DBA.

Electrical distribution subsystem requirements for MODE s 5 and 6 are covered in the Bases for LCO 3.8.10

.

ACTIONS A.1 With one or more required AC buses, load centers, motor

control centers, or distribution panels, except AC vital

buses, inoperable and a loss of f unction has not yet occurred, the remaining AC electrical power distribution

subsystems are capable of supporting the minimum safety

functions necessary to shut down the reactor and maintain it

in a safe shutdown condition, assuming no single failure.

The overall reliability is reduced, however, because a

single failure in the remaining power distribution

subsystems could result in the minimum required ESF

functions not being supported. Therefore, the required AC

buses, load centers, motor control centers, and distribution

panels must be restored to OPERABLE status within

eight hours.

Distribution Systems-Operating B 3.8.9 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.9-4 Revision 2 Condition A worst scenario is one train without AC power (i.e., no offsite power to the train and the associated DG

inoperable). In this condition, the unit is more vulnerable

to a complete loss of AC power. It is, therefore, imperative that the unit operator's attention be focused on

minimizing the potential for loss of power to the remaining train by stabilizing the unit, and on restoring power to the affected train. The eight hour time limit before requiring a unit shutdown in this condition is acceptable because of:

a. The potential for decreased safety if the unit operator's attention is diverted from the evaluations

and actions necessary to restore power to the affected

train, to the actions associated with taking the unit

to shutdown within this time limit; and b. The potential for an event in conjunction with a single failure of a redundant component in the train with AC

power.

The second Completion Time for Required Action A.1 establishes a limit on the maximum time allowed for any

combination of required distribution subsystems to be

inoperable during any single contiguous occurrence of

failing to meet the LCO. If Condition A is entered while, for instance, a DC bus is inoperable and subsequently

restored OPERABLE, the LCO may already have been not met for

up to two hours. This could lead to a total of ten hours, since initial failure of the LCO, to restore the AC

distribution system. At this time, a DC circuit could again

become inoperable, and AC distribution restored OPERABLE.

This could continue indefinitely.

The Completion Time allows for an exception to the normal "time zero" for beginning the allowed outage time "clock."

This will result in establishing the "time zero" at the time the LCO was initially not met, instead of the time Condition A was entered. The 16 hour1.851852e-4 days 0.00444 hours 2.645503e-5 weeks 6.088e-6 months Completion Time is an

acceptable limitation on this potential to fail to meet the

LCO indefinitely.

Distribution Systems-Operating B 3.8.9 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.9-5 Revision 2 B.1 With one or more AC vital buses inoperable and a loss of Function has not yet occurred, the remaining OPERABLE AC

vital buses are capable of supporting the minimum safety

functions necessary to shut down the unit and maintain it in

the safe shutdown condition. Overall reliability is reduced, however, since an additional single failure could result in the minimum required ESF functions not being

supported. Therefore, the AC vital bus must be restored to

OPERABLE status within two hours by powering the bus from an associated inverter via DC or the non-Class 1E 120 VAC bus

powered by an ESF m otor c ontrol c enter through a regulating transformer.

Condition B represents one or more AC vital buses without

power; potentially both the DC source and the associated AC

source are non

-functioning. In this situation, the unit is significantly more vulnerable to a complete loss of all

noninterruptible power. It is, therefore, imperative that

the operator's attention focus on stabilizing the unit, minimizing the potential for loss of power to the remaining

vital buses, and restoring power to the affected vital bus.

This two hour limit is more conservative than Completion Times allowed for the vast majority of components that are

without adequate vital AC power. Taking exception to

LCO 3.0.2 for components without adequate vital AC power, which would have the Required Action Completion Times

shorter than two hours if declared inoperable, is acceptable because of:

a. The potential for decreased safety by requiring a change in unit conditions (i.e., requiring a shutdown)

and not allowing stable operations to continue;

b. The potential for decreased safety by requiring entry into numerous Applicable Conditions and Required

Actions for components without adequate vital AC power

and not providing sufficient time for the operators to

perform the necessary evaluations and actions for

restoring power to the affected train; and

c. The potential for an event in conjunction with a single failure of a redundant component.

Distribution Systems-Operating B 3.8.9 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.9-6 Revision 2 The two hour Completion Time takes into account the importance to safety of restoring the AC vital bus to OPERABLE status, the redundant capability afforded by the

other OPERABLE vital buses, and the low probability of a DBA

occurring during this period.

The second Completion Time for Required Action B.1 establishes a limit on the maximum allowed for any

combination of required distribution subsystems to be

inoperable during any single contiguous occurrence of

failing to meet the LCO. If Condition B is entered while, for instance, an AC bus is inoperable and subsequently

returned OPERABLE, the LCO may already have been not met for

up to eight hours. This could lead to a total of ten hours, since initial failure of the LCO, to restore the vital bus

distribution system. At this time, an AC train could again

become inoperable, and vital bus distribution restored

OPERABLE. This could continue indefinitely.

This Completion Time allows for an exception to the normal "time zero" for beginning the allowed outage time "clock."

This will result in establishing the "time zero" at the time

the LCO was initially not met, instead of the time

Condition B was entered. The 16 hour1.851852e-4 days 0.00444 hours 2.645503e-5 weeks 6.088e-6 months Completion Time is an

acceptable limitation on this potential to fail to meet the

LCO indefinitely.

C.1 With one DC bus inoperable, the remaining DC electrical

power distribution subsystems are capable of supporting the

minimum safety functions necessary to shut down the reactor

and maintain it in a safe shutdown condition, assuming no

single failure. The overall reliability is reduced, however, because a single failure in the remaining DC electrical power distribution subsystem could result in the minimum required ESF functions not being supported.

Therefore, the DC bus must be restored to OPERABLE status

within two hours by powering the bus from the associated battery or charger.

Distribution Systems-Operating B 3.8.9 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.9-7 Revision 2 Condition C represents one DC bus without adequate DC power; potentially both with the battery significantly degraded and

the associated charger nonfunctioning. In this situation, the unit is significantly more vulnerable to a complete loss

of all DC power. It is, therefore, imperative that the

operator's attention focus on stabilizing the unit, minimizing the potential for loss of power to the remaining trains and restoring power to the affected train.

This two hour limit is more conservative than Completion Times allowed for the vast majority of components which

would be without power. Taking exception to LCO 3.0.2 for

components without adequate DC power, which would have

Required Action Completion Times shorter than 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months , is

acceptable because of:

a. The potential for decreased safety by requiring a change in unit conditions (i.e., requiring a shutdown)

while allowing stable operations to continue; b. The potential for decreased safety by requiring entry into numerous applicable Conditions and Required

Actions for components without DC power and not

providing sufficient time for the operators to perform

the necessary evaluations and actions for restoring

power to the affected train; and c. The potential for an event in conjunction with a single failure of a redundant component.

The two hour Completion Time for DC buses is consistent with Reference

2.

The second Completion Time for Required Action C.1

establishes a limit on the maximum time allowed for any

combination of required distribution subsystems to be

inoperable during any single contiguous occurrence of failing to meet the LCO. If Condition C is entered while, for instance, an AC bus is inoperable and subsequently

returned OPERABLE, the LCO may already have not been met for up to eight hours. This could lead to a total of ten hours, since initial failure of the LCO, to restore the DC

distribution system. At this time, an AC train could again

become inoperable, and DC distribution restored OPERABLE.

This could continue indefinitely.

Distribution Systems-Operating B 3.8.9 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.9-8 Revision 2 This Completion Time allows for an exception to the normal "time zero" for beginning the allowed outage time "clock."

This will result in establishing the "time zero" at the time

the LCO was initially not met, instead of the time

Condition C was entered. The 16 hour1.851852e-4 days 0.00444 hours 2.645503e-5 weeks 6.088e-6 months Completion Time is an acceptable limitation on this potential to fail to meet the LCO indefinitely.

D.1 and D.2 If the inoperable distribution subsystem cannot be restored

to OPERABLE status within the required Completion Time, the

unit must be brought to a MODE in which the LCO does not

apply. To achieve this status, the unit must be brought to

at least MODE 3 within six hours and to MODE 5 within 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months . The allowed Completion Times are reasonable, based on operating experience, to reach the required unit

conditions from full power conditions in an orderly manner

and without challenging unit systems.

E.1 Condition E corresponds to a level of degradation in the

electrical distribution system that causes a required safety

function to be lost. When more than one inoperable

electrical power distribution subsystem results in the loss

of a required function, the plant is in a condition outside

the accident analysis. Therefore, no additional time is

justified for continued operation. L imiting C ondition for O peration 3.0.3 must be entered immediately to commence a controlled shutdown.

SURVEILLANCE SR 3.8.9.1 REQUIREMENTS

This S R verifies that the AC, DC, and AC vital bus Electrical Power Distribution Systems are functioning

properly, with the correct circuit breaker alignment. The

correct breaker alignment ensures the appropriate separation

and independence of the electrical divisions is maintained, and the appropriate voltage is available to each required

bus. The verification of proper voltage availability on the

buses ensures that the required voltage is readily available

for motive as well as control functions for critical system Distribution Systems-Operating B 3.8.9 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.9-9 Revision 2 loads connected to these buses. The seven day Frequency takes into account the redundant capability of the AC, DC, and AC vital bus electrical power distribution subsystems, and other indications available in the C ontrol R oom that alert the operator to subsystem malfunctions.

REFERENCES 1. UFSAR

2. Regulatory Guide 1.93, "Availability of Electric Power Sources," December 1974

Distribution Systems-Operating B 3.8.9 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.9-10 Revision 2 Table B 3.8.9-1 (page 1 of 1)

AC and DC Electrical Power Distribution Systems(1) 4160 Volt Emergency Bus No. 11 (Unit 1), No. 21 (Unit 2) 4160 Volt Emergency Bus No. 14 (Unit 1), No. 24 (Unit 2)

480 Volt Emergency Bus No. 11A (Unit 1), No. 21A (Unit 2)

480 Volt Emergency Bus No. 11B (Unit 1), No. 21B (Unit 2)

480 Volt Emergency Bus No. 14A (Unit 1), No. 24A (Unit 2)

480 Volt Emergency Bus No. 14B (Unit 1), No. 24B (Unit 2)

480 Volt Emergency Bus No. 104R (Unit 1), No. 204R (Unit 2)

480 Volt Emergency Bus No. 114R (Unit 1), No. 214R (Unit 2)

120 Volt AC Vital Bus No. 11 (Unit 1), No. 21 (Unit 2)

120 Volt AC Vital Bus No. 12 (Unit 1), No. 22 (Unit 2)

120 Volt AC Vital Bus No. 13 (Unit 1), No. 23 (Unit 2)

120 Volt AC Vital Bus No. 14 (Unit 1), No. 24 (Unit 2)

125 Volt DC Bus No. 11 (Unit 1 and Unit 2)

125 Volt DC Bus No. 12 (Unit 1 and Unit 2)

125 Volt DC Bus No. 21 (Unit 1 and Unit 2) 125 Volt DC Bus No. 22 (Unit 1 and Unit 2)

(1) Each bus of the AC and DC Electrical Power Distribution System is a subsystem.

Distribution Systems-Shutdown B 3.8.10 B 3.8 ELECTRICAL POWER SYSTEMS B 3.8.10 Distribution Systems-Shutdown

BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.10-1 Revision 5 BACKGROUND A description of the AC, DC, and AC vital bus Electrical Power Distribution Systems is provided in the Bases for LCO 3.8.9.

The list of all required Distribution Systems-Shutdown is presented in Table B 3.8.10-1.

APPLICABLE The initial conditions of a DBA and transient analyses in SAFETY ANALYSES Reference 1, Chapters 6 and 14, assume ESF systems are OPERABLE. The AC, DC, and AC vital bus Electrical Power

Distribution Systems are designed to provide sufficient

capacity, capability, redundancy, and reliability to ensure

the availability of necessary power to ESF systems so that

the fuel, RCS, and containment design limits are not

exceeded.

The OPERABILITY of the AC, DC, and AC vital bus Electrical Power Distribution System is consistent with the initial

assumptions of the accident analyses and the requirements

for the supported systems' OPERABILITY.

The OPERABILITY of the minimum AC, DC, and AC vital bus electrical power distribution subsystems during MODEs 5

and 6, and during movement of irradiated fuel assemblies, ensures that: a. The unit can be maintained in the shutdown or refueling condition for extended periods; b. Sufficient instrumentation and control capability is available for monitoring and maintaining the unit

status; and c. Adequate power is provided to mitigate events postulated during shutdown, such as a fuel handling

accident.

The AC and DC Electrical Power Distribution Systems satisfy 10 CFR 50.36(c)(2)(ii), Criterion 3.

Distribution Systems-Shutdown B 3.8.10 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.10-2 Revision 5 LCO Various combinations of subsystems, equipment, and components are required OPERABLE by other LCOs, depending on

the specific unit condition. Implicit in those requirements

is the required OPERABILITY of necessary support required

features. This LCO explicitly requires energization of the

portions of the electrical distribution system necessary to support OPERABILITY of required systems, equipment, and components-all specifically addressed in each LCO and

implicitly required via the definition of OPERABILITY.

Maintaining these portions of the distribution system

energized ensures the availability of sufficient power to

operate the unit in a safe manner to mitigate the

consequences of postulated events during shutdown (e.g., fuel handling accidents).

APPLICABILITY The AC and DC electrical power distribution subsystems required to be OPERABLE in MODEs 5 and 6, and during

movement of irradiated fuel assemblies, provide assurance

that: a. Systems to provide adequate coolant inventory makeup are available for the irradiated fuel in the core; b. Systems needed to mitigate a fuel handling accident are available; c. Systems necessary to mitigate the effects of events that can lead to core damage during shutdown are

available; and d. Instrumentation and control capability is available for monitoring and maintaining the unit in a cold shutdown

condition and refueling condition.

The AC, DC, and AC vital bus electrical power distribution subsystem requirements for MODEs 1, 2, 3, and 4 are covered in LCO 3.8.9.

ACTIONS Limiting Condition for Operation 3.0.3 is not applicable while in MODEs 5 or 6. However, since irradiated fuel

assembly movement can occur in MODEs 1, 2, 3, or 4, the

ACTIONS have been modified by a Note stating that LCO 3.0.3

is not applicable. If moving irradiated fuel assemblies

while in MODEs 5 or 6, LCO 3.0.3 would not specify any Distribution Systems-Shutdown B 3.8.10 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.10-3 Revision 29 action. If moving irradiated fuel assemblies while in MODEs 1, 2, 3, or 4, the fuel movement is independent of

reactor operations. Therefore, in either case, inability to

suspend movement of irradiated fuel assemblies would not be

sufficient reason to require a reactor shutdown.

The ACTIONS have been modified by a second Note stating that performance of Required Actions shall not preclude

completion of actions to establish a safe conservative

position. This clarification is provided to avoid stopping

movement of irradiated fuel assemblies while in a non-

conservative position based on compliance with the Required

Actions.

A.1, A.2.1, A.2.2, A.2.3, and A.2.4 Although redundant required features may require redundant

trains of electrical power distribution subsystems to be

OPERABLE, one OPERABLE distribution subsystem train may be

capable of supporting sufficient required features to allow

continuation of movement of irradiated fuel assemblies. By allowing the option to declare required features associated

with an inoperable distribution subsystem inoperable, appropriate restrictions are implemented in accordance with

the affected distribution subsystems LCO's Required Actions.

In many instances, this option may involve undesired

administrative efforts. Therefore, the allowance for

sufficiently conservative actions is made [i.e., to suspend movement of irradiated fuel assemblies, and operations

involving positive reactivity additions that could result in

loss of the required SDM (MODE 5) or boron concentration (MODE 6)]. Suspending positive reactivity additions that

could result in failure to meet the minimum SDM or boron

concentration limit is required to assure continued safe

operation. Introduction of coolant inventory must be from sources that have a boron concentration greater than that required in the RCS for the minimum SDM or refueling boron

concentration. This may result in an overall reduction in

RCS boron concentration, but provides an acceptable margin

to maintaining subcritical operation. Introduction of

temperature changes including temperature increases when

operating with a positive MTC must also be evaluated to

ensure they do not result is a loss of the required SDM.

Distribution Systems-Shutdown B 3.8.10 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.10-4 Revision 38 Suspension of these activities shall not preclude completion

of actions to establish a safe conservative condition.

These actions minimize the probability of the occurrence of

postulated events. It is further required to immediately

initiate action to restore the required AC and DC electrical power distribution subsystems and to continue this action until restoration is accomplished in order to provide the

necessary power to the unit safety systems.

Notwithstanding performance of the above conservative

Required Actions, a required shutdown cooling (SDC)

subsystem may be inoperable. In this case, Required

Actions A.2.1 through A.2.

3 do not adequately address the concerns relating to coolant circulation and heat removal.

Pursuant to LCO 3.0.6, the SDC ACTIONS would not be entered.

Therefore, Required Action A.2.

4 is provided to direct declaring SDC inoperable, which results in taking the

appropriate SDC actions. The SDC subsystem(s) declared

inoperable and not in operation as a result of not meeting

this LCO, may be used if needed. However, the appropriate

actions are still required to be taken.

The Completion Time of immediately is consistent with the

required times for actions requiring prompt attention. The

restoration of the required distribution subsystems should

be completed as quickly as possible in order to minimize the time the unit safety systems may be without power.

SURVEILLANCE SR 3.8.10.1 REQUIREMENTS This SR verifies that the AC, DC, and AC vital bus Electrical Power Distribution System is functioning

properly, with all the buses energized. The verification of

proper voltage availability on the buses ensures that the

required power is readily available for motive as well as

control functions for critical system loads connected to

these buses. The seven day Frequency takes into account the

redundant capability of the electrical power distribution

subsystems, and other indications available in the Control Room that alert the operator to subsystem malfunctions.

Distribution Systems-Shutdown B 3.8.10 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.10-5 Revision 19 REFERENCES 1. UFSAR

Distribution Systems-Shutdown B 3.8.10 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.10-6 Revision 19 Table B 3.8.10-1 (page 1 of 1)

AC and DC Electrical Power Distribution Systems 1 4160 Volt Emergency Bus 1 480 Volt Emergency Bus

2 120 Volt AC Vital Busses

2 125 Volt DC Busses

2 125 Volt Battery Banks (one of which may be the reserve battery) (one associated battery charger per battery bank supplying the required DC busses)

ML12284A257

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