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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 | 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 | (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/ | : 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 | 13.8 kV SMECO line. When the SMECO line is credited as one of the qualified offsite circuits, the | ||
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unit. This results in maintaining at least one train 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: | onsite or offsite AC sources OPERABLE, during accident conditions in the event of: | ||
: a. An assumed loss of all offsite power; and | : a. An assumed loss of all offsite power; and | ||
: b. A single failure. | : b. A single failure. | ||
The AC sources satisfy 10 CFR 50.36(c)(2)(ii), Criterion 3. | The AC sources satisfy 10 CFR 50.36(c)(2)(ii), Criterion 3. | ||
Line 1,608: | Line 1,608: | ||
performed. The LCO 3.8.1.c DG will not start on an ESFAS signal for this Unit. | 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 AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-32 Revision 48 | REFERENCES 1. 10 CFR Part 50, Appendix A, "General Design Criteria for Nuclear Power Plants" 2. UFSAR AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-32 Revision 48 | ||
: 3. Regulatory Guide 1.9, Revision 3, "Selection, Design, Qualification, and Testing of Emergency Diesel Generator Units Used as Class 1E Onsite Electric Power | : 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 | Systems at Nuclear Power Plants," July 1993 | ||
: 4. Safety Guide 9, Revision 0, March 1971 | : 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 | : 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 | : 6. Regulatory Guide 1.93, Revision 0, "Availability of Electric Power Sources," December 1974 | ||
: 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 | : 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) | 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 | : 10. IEEE Standard 308-1991, "IEEE Standard Criteria for Class 1E Power Systems for Nuclear Power Generating | ||
Line 1,624: | Line 1,624: | ||
AC Sources-Shutdown B 3.8.2 B 3.8 ELECTRICAL POWER SYSTEMS B 3.8.2 AC Sources-Shutdown | 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: | 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; | : 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 | : b. Sufficient instrumentation and control capability is available for monitoring and maintaining the unit | ||
Line 1,658: | Line 1,658: | ||
must be conducted provided an acceptable level of risk is | 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: | 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 | : 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 | ||
Line 1,748: | Line 1,748: | ||
their respective LCOs (LCOs 3.7.8 and 3.7.9). | 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: | 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; | : 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; | : 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 | : c. Systems necessary to mitigate the effects of events that can lead to core damage during shutdown are | ||
available; and | available; and | ||
: d. Instrumentation and control capability is available for monitoring and maintaining the unit in a cold shutdown | : d. Instrumentation and control capability is available for monitoring and maintaining the unit in a cold shutdown | ||
Line 1,817: | Line 1,817: | ||
to suspend movement of irradiated fuel assemblies, and operations involving positive reactivity additions that | to suspend movement of irradiated fuel assemblies, and operations involving positive reactivity additions that | ||
could result in loss of the required SHUTDOWN MARGIN (SDM) | could result in loss of the required SHUTDOWN MARGIN (SDM) | ||
(MODE 5) or boron concentration (MODE 6). Suspending | (MODE 5) or boron concentration (MODE 6). Suspending | ||
Line 2,205: | Line 2,205: | ||
tank(s), but in no case is the time between receipt of new | 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: | 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; | : 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 | 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 | : 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). | : 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 | Failure to meet any of the above limits is cause for rejecting the new fuel oil, but does not represent a failure | ||
Line 2,278: | Line 2,278: | ||
fouling and provides data regarding the watertight integrity | fouling and provides data regarding the watertight integrity | ||
of the fuel oil system. The S R Frequencies are established by Reference | of the fuel oil system. The S R Frequencies are established by Reference | ||
: 3. This SR is for preventative maintenance. | : 3. This SR is for preventative maintenance. | ||
The presence of water does not necessarily represent failure | The presence of water does not necessarily represent failure | ||
Line 2,660: | Line 2,660: | ||
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. | 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 48 REFERENCES 1. UFSAR | DC Sources-Operating B 3.8.4 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.4-9 Revision 48 REFERENCES 1. UFSAR | ||
: 2. Safety Guide 6, Revision 0, "Independence Between Redundant Standby (Onsite) Power Sources and Between Their Distribution Systems, August 10, 1971 | : 2. Safety Guide 6, Revision 0, "Independence Between Redundant Standby (Onsite) Power Sources and Between Their Distribution Systems, August 10, 1971 | ||
: 3. IEEE Standard 308-1974, "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 | : 3. IEEE Standard 308-1974, "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 | 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- | : 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- | ||
Line 2,681: | Line 2,681: | ||
The OPERABILITY of the minimum DC sources during MODE s 5 and 6 and during movement of irradiated fuel assemblies | The OPERABILITY of the minimum DC sources during MODE s 5 and 6 and during movement of irradiated fuel assemblies | ||
ensures that: | ensures that: | ||
: a. The unit can be maintained in the shutdown or refueling condition for extended periods; | : 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 | : b. Sufficient instrumentation and control capability is available for monitoring and maintaining the unit | ||
Line 2,702: | Line 2,702: | ||
a safe manner and to mitigate the consequences of postulated events during shutdown (e.g., fuel handling accidents). | 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: | 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; | : 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 | : b. Required features necessary to mitigate the effects of events that can lead to core damage during shutdown are | ||
available; and | available; and | ||
: c. Instrumentation and control capability is available for monitoring and maintaining the unit in a cold shutdown | : c. Instrumentation and control capability is available for monitoring and maintaining the unit in a cold shutdown | ||
Line 2,926: | Line 2,926: | ||
SR 3.8.6.2 The quarterly inspection of specific gravity and voltage is | SR 3.8.6.2 The quarterly inspection of specific gravity and voltage is | ||
consistent with Reference | consistent with Reference | ||
: 2. | : 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 | 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 | ||
Line 3,063: | Line 3,063: | ||
to specific gravity measurement for determining the state of | to specific gravity measurement for determining the state of | ||
charge. This phenomenon is discussed in Reference | charge. This phenomenon is discussed in Reference | ||
: 2. Footnote (c) to Table 3.8.6-1 allows the float charge | : 2. Footnote (c) to Table 3.8.6-1 allows the float charge | ||
Line 3,105: | Line 3,105: | ||
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 | 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: | conditions in the event of: | ||
: a. An assumed loss of all offsite AC electrical power or all onsite AC electrical power; and | : a. An assumed loss of all offsite AC electrical power or all onsite AC electrical power; and | ||
: b. A worst case single failure. | : b. A worst case single failure. | ||
Line 3,149: | Line 3,149: | ||
battery is available as the uninterruptible power supply. | 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: | 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. | : 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. | ||
Line 3,230: | Line 3,230: | ||
The OPERABILITY of the minimum inverters to each AC vital | The OPERABILITY of the minimum inverters to each AC vital | ||
bus during MODE s 5 and 6 ensures that: | bus during MODE s 5 and 6 ensures that: | ||
: a. The unit can be maintained in the shutdown or refueling condition for extended periods; | : 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 | : b. Sufficient instrumentation and control capability is available for monitoring and maintaining the unit | ||
status; and | status; and | ||
: c. Adequate power is available to mitigate events postulated during shutdown, such as a fuel handling | : c. Adequate power is available to mitigate events postulated during shutdown, such as a fuel handling | ||
Line 3,255: | Line 3,255: | ||
APPLICABILITY The inverters required to be OPERABLE in MODEs 5 and 6 and during movement of irradiated fuel assemblies provide | APPLICABILITY The inverters required to be OPERABLE in MODEs 5 and 6 and during movement of irradiated fuel assemblies provide | ||
assurance that: | 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 | : 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 | ||
Line 3,450: | Line 3,450: | ||
inoperable. This applies to the onsite, safety-related redundant electrical power distribution subsystems. | inoperable. This applies to the onsite, safety-related redundant electrical power distribution subsystems. | ||
APPLICABILITY The electrical distribution subsystems are required to be OPERABLE in MODEs 1, 2, 3, and 4 to ensure that: | APPLICABILITY The electrical distribution subsystems 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 | : a. Acceptable fuel design limits and reactor coolant pressure boundary limits are not exceeded as a result | ||
Line 3,640: | Line 3,640: | ||
takes into account the redundant capability of the AC, DC, and AC vital bus electrical power distribution subsystems, and other indications available in the Control Room that alert the operator to subsystem malfunctions. | takes into account the redundant capability of the AC, DC, and AC vital bus electrical power distribution subsystems, and other indications available in the Control Room that alert the operator to subsystem malfunctions. | ||
REFERENCES 1. UFSAR | REFERENCES 1. UFSAR | ||
: 2. Regulatory Guide 1.93, "Availability of Electric Power Sources," December 1974 | : 2. Regulatory Guide 1.93, "Availability of Electric Power Sources," December 1974 | ||
Line 3,670: | Line 3,670: | ||
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. 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) | 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 | Distribution Systems-Shutdown B 3.8.10 B 3.8 ELECTRICAL POWER SYSTEMS B 3.8.10 Distribution Systems-Shutdown |
Revision as of 05:10, 28 April 2019
ML14267A233 | |
Person / Time | |
---|---|
Site: | Calvert Cliffs ![]() |
Issue date: | 09/19/2014 |
From: | Calvert Cliffs, Exelon Generation Co |
To: | Office of Nuclear Reactor Regulation |
Shared Package | |
ML14267A237 | List: |
References | |
Download: ML14267A233 (90) | |
Text
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 DGs 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 Sections 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
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 48 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 <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> Completion
Time takes into account the component OPERABILITY of the
redundant counterpart to the inoperable required feature.
Additionally, the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 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 <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
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 <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> 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.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 AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-8 Revision 48 action once per 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 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.
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 AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-9 Revision 48 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
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, AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-10 Revision 48 however, is no longer under the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> constraint imposed while in Condition B.
Consistent with Reference 7, 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> is reasonable to confirm that the OPERABLE 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.
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 <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />
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).
AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-11 Revision 48 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. 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 AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-12 Revision 48 conditions such as expected extreme summer temperatures and/or high demand.
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 <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
The 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> 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.
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.
AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-13 Revision 48 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.
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 <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 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 <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 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 3.8.1-14 Revision 48 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 <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. 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 <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, 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 <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />
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 <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> thereafter until
restoration of the required DG is accomplished. This
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 AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-15 Revision 48 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.
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 AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-16 Revision 48 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, however, is no longer under the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> constraint imposed
while in Condition E.
Consistent with Reference 6, 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> is reasonable to confirm that the OPERABLE 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.
AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-17 Revision 48 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 <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
The 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> 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.1.3 If the LCO 3.8.1.c DG cannot be restored to OPERABLE status
within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> 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 <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> 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 3.8.1-18 Revision 48 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 <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> from that allowed for one
train without offsite power (Required Action A.2). The
rationale for the reduction to 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> is that Reference 6
allows a Completion Time of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 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 <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />
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
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 <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
This level of degradation means that the offsite electrical AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-19 Revision 48 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 <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> Completion Time provides
a period of time to effect restoration of one of the offsite
circuits commensurate with the importance of maintaining an
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 <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. If two offsite sources are restored within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, unrestricted operation may continue. If
only one offsite source is restored within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, power
operation continues in accordance with Condition A or D, as
applicable.
AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-20 Revision 48 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 <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
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 <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> 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.
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 AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-21 Revision 48 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 <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />.
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 <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. 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.
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 AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-22 Revision 48 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.
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 AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-23 Revision 48 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.
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 AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-24 Revision 48 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.
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 AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-25 Revision 48 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.
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 AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-26 Revision 48 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
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
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 AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-27 Revision 48 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 0.84 for No. 1A DG and 0.83 for Nos. 1B, 2A, and 2B DGs.
These power factors are chosen based on the calculated highest kW value of DG loads during the postulated design
basis accidents.
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 during
the performance of this SR for No. 1A DG (Reference 9).
This SR is modified by two Notes, Note 1 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.
Note 2 ensures that the DG is tested under load conditions
that are as close to design basis conditions as practicable.
When synchronized with offsite power, testing should be performed at a power factor of 0.84 for No. 1A DG and 0.83 for Nos. 1B, 2A, and 2B DGs. These power factors are representative of the actual inductive loading a DG would see under design basis accident conditions. Under
certain conditions, however, Note 2 allows the surveillance to be conducted at a power factor other than 0.84 for No.
AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-28 Revision 48 1A DG and 0.83 for Nos. 1B, 2A, and 2B DGs. These conditions occur when grid voltage is high, and the additional field excitation needed to get the power factor to 0.84 for No. 1A DG and 0.83 for Nos. 1B, 2A, and 2B DGs results in voltages on the emergency busses that are too high. Conditions can also occur that could result in emergency bus voltages which are too low. Under these conditions, the power factor shall be maintained as close a
practicable to 0.84 for No. 1A DG and 0.83 for Nos. 1B, 2A, and 2B DGs while maintaining acceptable voltages on the
emergency busses.
The 24 month Frequency is adequate to ensure DG OPERABILITY, takes into consideration unit conditions required to perform
the surveillance, and is intended to be consistent with
expected fuel cycle lengths.
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-AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-29 Revision 48 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 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 AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-30 Revision 48 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
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.
AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-31 Revision 48 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. 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 AC Sources-Operating B 3.8.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.1-32 Revision 48
- 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
- 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 47 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. Fuel Oil Storage Tank 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 No
. 21 ensure s that at least seven days of fuel oil will be available 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 Diesel Fuel Oil B 3.8.3 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.3-2 Revision 47 least 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 Nos. 1B, 2A, and 2B are loaded to 3500 kW.
APPLICABLE The initial conditions of DBA and transient analyses in SAFETY ANALYSES Reference 1, and Chapters 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 Fuel Oil Storage Tank 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. Fuel Oil Storage Tank 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 <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> 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 <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />. 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 <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> 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 <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />.
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
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 48 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 References 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, two 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 <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> 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 48 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 <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 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 MODEs 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, two battery chargers, and the corresponding control equipment and interconnecting cabling supplying power to the DC Sources-Operating B 3.8.4 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.4-3 Revision 48 associated 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 DC Sources-Operating B 3.8.4 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.4-4 Revision 48 complete loss of DC power to the affected channel. The 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> 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 <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />. The
2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> 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 <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and to MODE 5 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. 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 DC Sources-Operating B 3.8.4 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.4-5 Revision 48 with Reference 6 and the initial state of charge conditions 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.
DC Sources-Operating B 3.8.4 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.4-6 Revision 48 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
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 DC Sources-Operating B 3.8.4 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.4-7 Revision 48 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.
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 <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> 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 DC Sources-Operating B 3.8.4 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.4-8 Revision 48 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
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 48 REFERENCES 1. UFSAR
- 2. Safety Guide 6, Revision 0, "Independence Between Redundant Standby (Onsite) Power Sources and Between Their Distribution Systems, August 10, 1971
- 3. IEEE Standard 308-1974, "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 <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 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 <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
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:
- 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 <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to fix the inoperable
inverter and return it to service. The 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 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 <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. 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 Sections 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
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 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.
Electrical distribution subsystem requirements for MODEs 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 function 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 48 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. 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 motor control center 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.
Distribution Systems-Operating B 3.8.9 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.9-5 Revision 48 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.
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.
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 3.8.9-6 Revision 48 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 <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />, 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.
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 <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. 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.
Distribution Systems-Operating B 3.8.9 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.8.9-7 Revision 48 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. Limiting Condition for
Operation 3.0.3 must be entered immediately to commence a controlled shutdown.
SURVEILLANCE SR 3.8.9.1 REQUIREMENTS This SR 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
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 Control Room 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 3.8.9-8 Revision 48 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)