ML15257A201: Difference between revisions
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B 3.6.1 Containment | B 3.6.1 Containment | ||
BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.1-1 Revision 2 BACKGROUND The | BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.1-1 Revision 2 BACKGROUND The C ontainment Structure consists of the concrete building , its steel liner, and the penetrations through this structure. The structure is designed to contain radioactive material that may | ||
be released from the reactor core following a Design Basis Accident (DBA). Additionally, this structure provides shielding from the fission products that may be present in the | be released from the reactor core following a Design Basis Accident (DBA). Additionally, this structure provides shielding from the fission products that may be present in the | ||
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containment atmosphere following accident conditions. | containment atmosphere following accident conditions. | ||
The | The C ontainment Structure is a reinforced concrete structure with a cylindrical wall, a flat foundation mat, and a shallow dome roof. The C ontainment Structure has ungrouted tendons, therefore, the cylinder wall is prestressed with a post-tensioning system in the vertical and horizontal directions, and the dome roof is prestressed utilizing a three-way post-tensioning system. The inside surface of the C ontainment Structure is lined with a carbon steel liner to ensure a high degree of leak tightness during operating and accident conditions. | ||
The concrete building is required for structural integrity of the | The concrete building is required for structural integrity of the C ontainment Structure under DBA conditions. The steel liner and its penetrations establish the leakage limiting boundary of the C ontainment Structure. Maintaining the C ontainment Structure OPERABLE limits the leakage of fission product radioactivity from the C ontainment Structure to the environment. | ||
. Maintaining the | Surveillance Requirement (SR) 3.6.1.1 leakage rate requirements comply with Reference 1 | ||
Surveillance Requirement ( | |||
SR) 3.6.1.1 leakage rate requirements comply with Reference 1 | |||
, as modified by approved exemptions. | , as modified by approved exemptions. | ||
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Satisfactory leakage rate test results are a requirement for the establishment of Containment Structure OPERABILITY. | Satisfactory leakage rate test results are a requirement for the establishment of Containment Structure OPERABILITY. | ||
The Containment Structure satisfies 10 CFR 50.36(c)(2)(ii), | The Containment Structure satisfies 10 CFR 50.36(c)(2)(ii), Criterion 3. | ||
Criterion 3. | LCO Containment OPERABILITY is maintained by limiting leakage to 1.0 L a (276,8 00 SCCM), except prior to the first startup after performing a required Containment Leakage Rate Testing Program leakage test. At this time the applicable leakage limits must | ||
LCO Containment OPERABILITY is maintained by limiting leakage to 1.0 | |||
be met. | be met. | ||
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rates assumed in the safety analysis. | rates assumed in the safety analysis. | ||
Individual leakage rates specified for the containment air lock (LCO 3.6.2) are not specifically part of the acceptance criteria of Reference 1 | Individual leakage rates specified for the containment air lock (LCO 3.6.2) are not specifically part of the acceptance criteria of Reference 1. Therefore, leakage rates exceeding these individual limits only result in the C ontainment Structure being inoperable when the leakage results in exceeding the overall acceptance criteria of 1.0 L | ||
. Therefore, leakage rates exceeding these individual limits only result in the | : a. APPLICABILITY In MODE s 1, 2, 3, and 4, a DBA could cause a release of radioactive material into the C ontainment Structure. In MODE s 5 and 6, the probability and consequences of these events are reduced due to the pressure and temperature limitations of these MODE | ||
: a. APPLICABILITY In MODE s 1, 2, 3, and 4, a DBA could cause a release of radioactive material into the | : s. Therefore, the C ontainment Structure is not required to be OPERABLE in MODE 5 to prevent leakage of radioactive material from the C ontainment Structure. The requirements for the C ontainment Structure during MODE 6 are addressed in LCO 3.9.3 | ||
. In | . ACTIONS A.1 In the event the C ontainment Structure is inoperable, the C ontainment Structure must be restored to OPERABLE status within one hour. The one hour Completion Time provides a period of time to correct the problem commensurate with the importance of maintaining the C ontainment Structure during MODE s 1, 2, 3, and 4. This time period also ensures that the probability of an accident (requiring C ontainment OPERABILITY) occurring during periods when the C ontainment Structure is inoperable is minimal. | ||
: s. Therefore, the | B.1 and B.2 If the C ontainment Structure cannot be restored to OPERABLE status within the required Completion Time, the plant must be brought to a MODE in which the LCO does not apply. To achieve this status, the plant must be brought to at least MODE 3 within 6 hours and to MODE 5 within 36 hours. The allowed Completion Times are reasonable, based on operating experience, to reach | ||
. The requirements for the | |||
. ACTIONS A.1 In the event the | |||
B.1 and B.2 If the | |||
the required plant conditions from full Containment B 3.6.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.1-4 Revision 41 power conditions in an orderly manner and without challenging plant systems. | the required plant conditions from full Containment B 3.6.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.1-4 Revision 41 power conditions in an orderly manner and without challenging plant systems. | ||
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leakage, prior to the first startup after performing a required | leakage, prior to the first startup after performing a required | ||
Containment Leakage Rate Testing Program, is required to be 0.6 | Containment Leakage Rate Testing Program, is required to be 0.6 L a (166,080 SCCM) for combined Type B and C leakage and 0.75 L a (207,6 00 SCCM) for overall Type A leakage. At all other times between required leakage rate tests, the acceptance criteria is based on an overall Type A leakage limit of 1.0 L a. At 1.0 L a , the offsite dose consequences are bounded by the assumptions of the safety analysis. Surveillance | ||
Requirement Frequencies are as required by Containment Leakage | Requirement Frequencies are as required by Containment Leakage | ||
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Frequency are consistent with the recommendations of Reference 3. | Frequency are consistent with the recommendations of Reference 3. | ||
REFERENCES 1. 10 CFR Part 50, Appendix J, "Primary Reactor Containment Leakage Testing for Water-Cooled Power Reactors" Option B, | REFERENCES 1. 10 CFR Part 50, Appendix J, "Primary Reactor Containment Leakage Testing for Water-Cooled Power Reactors" Option B, "Performance-Based Requirements" 2. Updated Final Safety Analysis Report (UFSAR) | ||
"Performance-Based Requirements" 2. Updated Final Safety Analysis Report (UFSAR) | |||
Containment B 3.6.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.1-5 Revision 41 3. American Society of Mechanical Engineers Boiler and Pressure Vessel Code, 1992 Edition through the 1992 | Containment B 3.6.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.1-5 Revision 41 3. American Society of Mechanical Engineers Boiler and Pressure Vessel Code, 1992 Edition through the 1992 | ||
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fission products to the environment is controlled by the rate of containment leakage. The Containment Structure is designed with an allowable leakage rate of 0.16% of containment air weight per day (Reference 1, Chapter 5). | fission products to the environment is controlled by the rate of containment leakage. The Containment Structure is designed with an allowable leakage rate of 0.16% of containment air weight per day (Reference 1, Chapter 5). | ||
This leakage rate is defined in 10 CFR Part 50, Appendix J, | This leakage rate is defined in 10 CFR Part 50, Appendix J, Option B, as the maximum allowable containment leakage rate | ||
Option B, as the maximum allowable containment leakage rate | |||
at the calculated peak containment internal pressure, P a (49.4 psig), following a design basis LOCA. This allowable | at the calculated peak containment internal pressure, P a (49.4 psig), following a design basis LOCA. This allowable | ||
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imposed on the SRs associated with the air lock. | imposed on the SRs associated with the air lock. | ||
The containment air locks satisfy 10 CFR 50.36(c)(2)(ii), | The containment air locks satisfy 10 CFR 50.36(c)(2)(ii), Criterion 3. | ||
Criterion 3. | |||
LCO Each containment air lock forms part of the containment pressure boundary. As part of the containment pressure | LCO Each containment air lock forms part of the containment pressure boundary. As part of the containment pressure | ||
boundary, the air lock safety function is related to control | boundary, the air lock safety function is related to control | ||
of the containment leakage rate resulting from a DBA. Thus, | of the containment leakage rate resulting from a DBA. Thus, each air lock's structural integrity and leak tightness, are | ||
each air lock's structural integrity and leak tightness, are | |||
essential to the successful mitigation of such an event. | essential to the successful mitigation of such an event. | ||
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performed from the barrel side of the door then it is | performed from the barrel side of the door then it is | ||
permissible to enter the air lock through the OPERABLE door, | permissible to enter the air lock through the OPERABLE door, which means there is a short time during which the | ||
which means there is a short time during which the | |||
containment boundary is not intact (during access through | containment boundary is not intact (during access through | ||
the OPERABLE door). The ability to open the OPERABLE door, | the OPERABLE door). The ability to open the OPERABLE door, even if it means the containment boundary is temporarily not | ||
even if it means the containment boundary is temporarily not | |||
intact, is acceptable because of the low probability of an | intact, is acceptable because of the low probability of an | ||
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open. After each entry and exit, the OPERABLE door must be | open. After each entry and exit, the OPERABLE door must be | ||
immediately closed. If as low as reasonably achievable | immediately closed. If as low as reasonably achievable (ALARA) conditions permit, entry and exit should be via an OPERABLE air lock. | ||
(ALARA) conditions permit, entry and exit should be via an OPERABLE air lock. | |||
A second Note has been added to provide clarification that, for this LCO, separate Condition entry is allowed for each | A second Note has been added to provide clarification that, for this LCO, separate Condition entry is allowed for each | ||
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leakage limit. | leakage limit. | ||
Containment Air Locks B 3.6.2 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.2-4 Revision 2 A.1, A.2, and A.3 With one air lock door inoperable in one or more containment air locks, the OPERABLE door must be verified closed | Containment Air Locks B 3.6.2 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.2-4 Revision 2 A.1, A.2, and A.3 With one air lock door inoperable in one or more containment air locks, the OPERABLE door must be verified closed (Required Action A.1) in each affected containment air lock. | ||
(Required Action A.1) in each affected containment air lock. | |||
This ensures that a leak tight containment barrier is | This ensures that a leak tight containment barrier is | ||
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the Required Actions. Note 2 allows use of the air lock for | the Required Actions. Note 2 allows use of the air lock for | ||
entry and exit for seven days under administrative controls if both air locks have an inoperable door. This seven day restriction begins when the second air lock is discovered inoperable. Containment entry may be required to perform Technical Specifications Surveillances and Required Actions, as well as other activities on equipment inside the Containment Structure that are required by Technical Specifications or activities on equipment that support Technical Specifications-required equipment. This Note is not intended to preclude performing other activities | entry and exit for seven days under administrative controls if both air locks have an inoperable door. This seven day restriction begins when the second air lock is discovered inoperable. Containment entry may be required to perform Technical Specifications Surveillances and Required Actions, as well as other activities on equipment inside the Containment Structure that are required by Technical Specifications or activities on equipment that support Technical Specifications-required equipment. This Note is not intended to preclude performing other activities (i.e., non-Technical Specifications-required activities) if the Containment Structure was entered, using the inoperable air lock, to perform an allowed activity listed above. This | ||
(i.e., non-Technical Specifications-required activities) if the Containment Structure was entered, using the inoperable air lock, to perform an allowed activity listed above. This | |||
allowance is acceptable due to the low probability of an | allowance is acceptable due to the low probability of an | ||
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plant must be brought to a MODE in which the LCO does not | plant must be brought to a MODE in which the LCO does not | ||
apply. To achieve this status, the plant must be brought to Containment Air Locks B 3.6.2 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.2-7 Revision 2 at least MODE 3 within 6 hours and to MODE 5 within 36 hours. The allowed Completion Times are reasonable, | apply. To achieve this status, the plant must be brought to Containment Air Locks B 3.6.2 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.2-7 Revision 2 at least MODE 3 within 6 hours and to MODE 5 within 36 hours. The allowed Completion Times are reasonable, based on operating experience, to reach the required plant | ||
based on operating experience, to reach the required plant | |||
conditions from full power conditions in an orderly manner and without challenging plant systems. | conditions from full power conditions in an orderly manner and without challenging plant systems. | ||
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Containment isolation occurs upon receipt of a high containment pressure signal. The containment isolation | Containment isolation occurs upon receipt of a high containment pressure signal. The containment isolation | ||
signal closes automatic containment isolation valves in fluid penetrations, not required for operation of Engineered Safety Feature (ESF) systems, in order to prevent leakage of radioactive material. Upon actuation of safety injection, | signal closes automatic containment isolation valves in fluid penetrations, not required for operation of Engineered Safety Feature (ESF) systems, in order to prevent leakage of radioactive material. Upon actuation of safety injection, automatic containment isolation valves also isolate systems | ||
automatic containment isolation valves also isolate systems | |||
not required for the Containment Structure or Reactor Coolant System (RCS) heat removal. Other penetrations are | not required for the Containment Structure or Reactor Coolant System (RCS) heat removal. Other penetrations are | ||
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The DBA analysis assumes that, within 60 seconds after the accident, isolation of the Containment Structure is complete | The DBA analysis assumes that, within 60 seconds after the accident, isolation of the Containment Structure is complete | ||
and leakage terminated except for the design leakage rate, | and leakage terminated except for the design leakage rate, L a. The containment isolation total response time of 60 seconds includes signal delay, diesel generator startup (for loss of offsite power), and containment isolation valve | ||
stroke times. | stroke times. | ||
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Condition entry and application of associated Required | Condition entry and application of associated Required | ||
Actions. | Actions. | ||
The ACTIONS are further modified by a third Note, which ensures that appropriate remedial actions are taken, if Containment Isolation Valves B 3.6.3 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.3-4 Revision 2 necessary, if the affected systems are rendered inoperable by an inoperable containment isolation valve. | The ACTIONS are further modified by a third Note, which ensures that appropriate remedial actions are taken, if Containment Isolation Valves B 3.6.3 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.3-4 Revision 2 necessary, if the affected systems are rendered inoperable by an inoperable containment isolation valve. | ||
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system. For penetration flow paths with one or more | system. For penetration flow paths with one or more | ||
containment isolation valves and a closed system, | containment isolation valves and a closed system, Condition C provides appropriate actions. | ||
Condition C provides appropriate actions. | |||
Required Action A.2 is modified by a Note that applies to isolation devices located in high radiation areas and allows | Required Action A.2 is modified by a Note that applies to isolation devices located in high radiation areas and allows | ||
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25 Service Water Inlet 26 Service Water Inlet 27 Service Water Inlet 28 Service Water Inlet 29 Service Water Return 30 Service Water Return 31 Service Water Return 32 Service Water Return 33 Main Feedwater 34 Main Feedwater 35 Main Steam 36 Main Steam 38 Demineralized Water | 25 Service Water Inlet 26 Service Water Inlet 27 Service Water Inlet 28 Service Water Inlet 29 Service Water Return 30 Service Water Return 31 Service Water Return 32 Service Water Return 33 Main Feedwater 34 Main Feedwater 35 Main Steam 36 Main Steam 38 Demineralized Water | ||
43A Steam Generator Bottom Blowdown 43B Steam Generator Bottom Blowdown 44 Fire Protection Containment Isolation Valves B 3.6.3 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.3-8 Revision 55 Required Action C.2 is modified by a Note that applies to valves and blind flanges, located in high radiation areas, | 43A Steam Generator Bottom Blowdown 43B Steam Generator Bottom Blowdown 44 Fire Protection Containment Isolation Valves B 3.6.3 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.3-8 Revision 55 Required Action C.2 is modified by a Note that applies to valves and blind flanges, located in high radiation areas, and allows these devices to be verified closed by use of | ||
and allows these devices to be verified closed by use of | |||
administrative means. Allowing verification by | administrative means. Allowing verification by | ||
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SURVEILLANCE SR 3.6.3.1 REQUIREMENTS This SR ensures that the containment vent valves are closed as required, or, if open, open for an allowable reason. If | SURVEILLANCE SR 3.6.3.1 REQUIREMENTS This SR ensures that the containment vent valves are closed as required, or, if open, open for an allowable reason. If | ||
a containment vent valve is open in violation of this SR, | a containment vent valve is open in violation of this SR, the valve is considered inoperable. If the inoperable valve | ||
the valve is considered inoperable. If the inoperable valve | |||
is not otherwise known to have excessive leakage when | is not otherwise known to have excessive leakage when | ||
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to meet the SR during the time that they are open. This SR Containment Isolation Valves B 3.6.3 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.3-10 Revision 55 does not apply to valves that are locked, sealed, or otherwise secured in the closed position, since these were | to meet the SR during the time that they are open. This SR Containment Isolation Valves B 3.6.3 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.3-10 Revision 55 does not apply to valves that are locked, sealed, or otherwise secured in the closed position, since these were | ||
verified to be in the correct position upon locking, | verified to be in the correct position upon locking, sealing, or securing. | ||
sealing, or securing. | |||
The Note allows valves and blind flanges located in high radiation areas to be verified closed by use of administrative means. Allowing verification by | The Note allows valves and blind flanges located in high radiation areas to be verified closed by use of administrative means. Allowing verification by | ||
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administrative means is considered acceptable, since access | administrative means is considered acceptable, since access | ||
to these areas is typically restricted during MODEs 1, 2, | to these areas is typically restricted during MODEs 1, 2, and 3 for ALARA reasons. Therefore, the probability of | ||
and 3 for ALARA reasons. Therefore, the probability of | |||
misalignment of these containment isolation valves, once | misalignment of these containment isolation valves, once | ||
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or integrity be set below the lower limits, the external | or integrity be set below the lower limits, the external | ||
pressure limits may be exceeded during barometric pressure changes. | pressure limits may be exceeded during barometric pressure changes. APPLICABLE Containment internal pressure is an initial condition used SAFETY ANALYSES in the DBA analyses to establish the maximum peak containment internal pressure. The limiting DBA considered | ||
APPLICABLE Containment internal pressure is an initial condition used SAFETY ANALYSES in the DBA analyses to establish the maximum peak containment internal pressure. The limiting DBA considered | |||
for determining the maximum containment internal pressure is | for determining the maximum containment internal pressure is | ||
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the LOCA. A LOCA at 102% RATED THERMAL POWER and + 1.0 psig initial containment pressure results in the highest | the LOCA. A LOCA at 102% RATED THERMAL POWER and + 1.0 psig initial containment pressure results in the highest | ||
calculated internal containment pressure (P a) below the internal design pressure of 50.0 psig. The postulated DBAs are analyzed assuming degraded containment ESF systems | calculated internal containment pressure (P a) below the internal design pressure of 50.0 psig. The postulated DBAs are analyzed assuming degraded containment ESF systems (i.e., assuming the loss of one ESF bus, which is the worst | ||
(i.e., assuming the loss of one ESF bus, which is the worst | |||
case single active failure, resulting in one train of the | case single active failure, resulting in one train of the | ||
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of 1.0 psig, a total pressure below the design value of 50 psig would result. | of 1.0 psig, a total pressure below the design value of 50 psig would result. | ||
Containment pressure satisfies 10 CFR 50.36(c)(2)(ii), | Containment pressure satisfies 10 CFR 50.36(c)(2)(ii), Criterion 2. | ||
Criterion 2. | |||
LCO Maintaining containment pressure less than or equal to the LCO upper pressure limit ensures that, in the event of a | LCO Maintaining containment pressure less than or equal to the LCO upper pressure limit ensures that, in the event of a | ||
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to ensure initial conditions assumed in the accident | to ensure initial conditions assumed in the accident | ||
analysis are maintained, the LCO is applicable in MODEs 1, | analysis are maintained, the LCO is applicable in MODEs 1, 2, 3, and 4. | ||
2, 3, and 4. | |||
In MODEs 5 and 6, the probability and consequences of these events are reduced due to the pressure and temperature | In MODEs 5 and 6, the probability and consequences of these events are reduced due to the pressure and temperature | ||
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Containment Air Temperature B 3.6.5 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.5-2 Revision 2 The initial containment average air temperature condition of 120°F resulted in a maximum vapor temperature described in Reference 1. The consequence of exceeding the design temperature for extended periods may be the potential for degradation of the containment structure under accident loads. | Containment Air Temperature B 3.6.5 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.5-2 Revision 2 The initial containment average air temperature condition of 120°F resulted in a maximum vapor temperature described in Reference 1. The consequence of exceeding the design temperature for extended periods may be the potential for degradation of the containment structure under accident loads. | ||
Containment average air temperature satisfies 10 CFR 50.36(c)(2)(ii), Criterion 2. | Containment average air temperature satisfies 10 CFR 50.36(c)(2)(ii), Criterion 2. | ||
LCO During a DBA, with an initial containment average air temperature less than or equal to the LCO temperature limit, | LCO During a DBA, with an initial containment average air temperature less than or equal to the LCO temperature limit, the resultant peak accident temperature is maintained below | ||
the resultant peak accident temperature is maintained below | |||
the containment design temperature. As a result, the | the containment design temperature. As a result, the | ||
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within the limit assumed for the containment analyses. In | within the limit assumed for the containment analyses. In | ||
order to determine the containment average air temperature, | order to determine the containment average air temperature, an arithmetic average is calculated using measurements taken | ||
an arithmetic average is calculated using measurements taken | |||
from the containment dome [1(2)-TI-5309] and the containment | from the containment dome [1(2)-TI-5309] and the containment | ||
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containment atmosphere. The Surveillance Frequency is controlled under the Surveillance Frequency Control Program. | containment atmosphere. The Surveillance Frequency is controlled under the Surveillance Frequency Control Program. | ||
REFERENCES 1. UFSAR, Section 14.20, "Containment Response" | REFERENCES 1. UFSAR, Section 14.20, "Containment Response" Containment Spray and Cooling Systems B 3.6.6 B 3.6 CONTAINMENT SYSTEMS | ||
Containment Spray and Cooling Systems B 3.6.6 B 3.6 CONTAINMENT SYSTEMS | |||
B 3.6.6 Containment Spray and Cooling Systems | B 3.6.6 Containment Spray and Cooling Systems | ||
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approximately 50% of the design cooling requirement. Each | approximately 50% of the design cooling requirement. Each | ||
train includes a containment spray pump, spray headers, | train includes a containment spray pump, spray headers, nozzles, valves, and piping. Each train is powered from a | ||
nozzles, valves, and piping. Each train is powered from a | |||
separate ESF bus. The refueling water tank (RWT) supplies | separate ESF bus. The refueling water tank (RWT) supplies | ||
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borated water to the containment spray during the injection | borated water to the containment spray during the injection | ||
phase of operation. In the recirculation mode of operation, | phase of operation. In the recirculation mode of operation, containment spray pump suction is transferred from the RWT | ||
containment spray pump suction is transferred from the RWT | |||
to the containment sump(s). Each spray system flow path | to the containment sump(s). Each spray system flow path | ||
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Containment Spray and Cooling Systems B 3.6.6 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.6-3 Revision 39 APPLICABLE The Containment Spray and Cooling Systems limit the SAFETY ANALYSES temperature and pressure that could be experienced following a DBA. The limiting DBAs considered relative to containment | Containment Spray and Cooling Systems B 3.6.6 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.6-3 Revision 39 APPLICABLE The Containment Spray and Cooling Systems limit the SAFETY ANALYSES temperature and pressure that could be experienced following a DBA. The limiting DBAs considered relative to containment | ||
temperature and pressure are LOCA and main SLB. The DBA, | temperature and pressure are LOCA and main SLB. The DBA, LOCA, and main SLB are analyzed using computer codes | ||
LOCA, and main SLB are analyzed using computer codes | |||
designed to predict the resultant containment pressure and temperature transients. No DBAs are assumed to occur simultaneously or consecutively. The postulated DBAs are | designed to predict the resultant containment pressure and temperature transients. No DBAs are assumed to occur simultaneously or consecutively. The postulated DBAs are | ||
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steam line break and 70.9 seconds for a LOCA, includes | steam line break and 70.9 seconds for a LOCA, includes | ||
diesel generator startup (for loss of offsite power), | diesel generator startup (for loss of offsite power), sequencing equipment onto the emergency bus, containment spray pump startup, and spray line filling (Reference 1, Chapter 7). | ||
sequencing equipment onto the emergency bus, containment spray pump startup, and spray line filling (Reference 1, | |||
Chapter 7). | |||
The performance of the containment cooling train for post-accident conditions is given in Reference 1, Chapter 6. The | The performance of the containment cooling train for post-accident conditions is given in Reference 1, Chapter 6. The | ||
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Completion Time takes into account the redundant heat | Completion Time takes into account the redundant heat | ||
removal capability afforded by the Containment Spray System, | removal capability afforded by the Containment Spray System, reasonable time for repairs, and the low probability of a | ||
reasonable time for repairs, and the low probability of a | |||
DBA occurring during this period. | DBA occurring during this period. | ||
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position prior to being secured. This SR also does not | position prior to being secured. This SR also does not | ||
apply to valves that cannot be inadvertently misaligned, | apply to valves that cannot be inadvertently misaligned, such as check valves. This SR does not require any testing | ||
or valve manipulation. Rather, it involves verifying, through a system walkdown, that those valves outside the | |||
or valve manipulation. Rather, it involves verifying, | |||
through a system walkdown, that those valves outside the | |||
Containment Structure and capable of potentially being | Containment Structure and capable of potentially being | ||
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are fully open provides assurance that the design flow rate | are fully open provides assurance that the design flow rate | ||
assumed in the safety analyses will be achieved | assumed in the safety analyses will be achieved (Reference 1, Chapter 7). The Surveillance Frequency is controlled under the Surveillance Frequency Control Program. | ||
(Reference 1, Chapter 7). The Surveillance Frequency is controlled under the Surveillance Frequency Control Program. | |||
Containment Spray and Cooling Systems B 3.6.6 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.6-8 Revision 55 SR 3.6.6.4 Verifying that each containment spray pumps developed head at the flow test point is greater than or equal to the | Containment Spray and Cooling Systems B 3.6.6 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.6-8 Revision 55 SR 3.6.6.4 Verifying that each containment spray pumps developed head at the flow test point is greater than or equal to the | ||
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of this SR is in accordance with the Inservice Testing | of this SR is in accordance with the Inservice Testing | ||
Program. | Program. | ||
SR 3.6.6.5 and SR 3.6.6.6 These SRs verify that each automatic containment spray valve actuates to its correct position and that each containment | SR 3.6.6.5 and SR 3.6.6.6 These SRs verify that each automatic containment spray valve actuates to its correct position and that each containment | ||
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IRS B 3.6.8 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.8-4 Revision 55 SURVEILLANCE SR 3.6.8.1 REQUIREMENTS Initiating each IRS train from the Control Room and operating it for 15 minutes ensures that all trains are OPERABLE and that all associated controls are functioning | IRS B 3.6.8 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.8-4 Revision 55 SURVEILLANCE SR 3.6.8.1 REQUIREMENTS Initiating each IRS train from the Control Room and operating it for 15 minutes ensures that all trains are OPERABLE and that all associated controls are functioning | ||
properly. It also ensures that motor failure can be detected for corrective action. The Surveillance Frequency is controlled under the Surveillance Frequency Control Program. | properly. It also ensures that motor failure can be detected for corrective action. The Surveillance Frequency is controlled under the Surveillance Frequency Control Program. SR 3.6.8.2 This SR verifies that the required IRS filter testing is performed in accordance with the Ventilation Filter Testing | ||
SR 3.6.8.2 This SR verifies that the required IRS filter testing is performed in accordance with the Ventilation Filter Testing | |||
Program. The IRS filter tests are in accordance with | Program. The IRS filter tests are in accordance with |
Revision as of 23:45, 8 July 2018
ML15257A201 | |
Person / Time | |
---|---|
Site: | Calvert Cliffs ![]() |
Issue date: | 09/04/2015 |
From: | Exelon Generation Co |
To: | Office of Nuclear Reactor Regulation |
Shared Package | |
ML15257A190 | List: |
References | |
Download: ML15257A201 (42) | |
Text
Containment B 3.6.1 B 3.6 CONTAINMENT SYSTEMS
B 3.6.1 Containment
BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.1-1 Revision 2 BACKGROUND The C ontainment Structure consists of the concrete building , its steel liner, and the penetrations through this structure. The structure is designed to contain radioactive material that may
be released from the reactor core following a Design Basis Accident (DBA). Additionally, this structure provides shielding from the fission products that may be present in the
containment atmosphere following accident conditions.
The C ontainment Structure is a reinforced concrete structure with a cylindrical wall, a flat foundation mat, and a shallow dome roof. The C ontainment Structure has ungrouted tendons, therefore, the cylinder wall is prestressed with a post-tensioning system in the vertical and horizontal directions, and the dome roof is prestressed utilizing a three-way post-tensioning system. The inside surface of the C ontainment Structure is lined with a carbon steel liner to ensure a high degree of leak tightness during operating and accident conditions.
The concrete building is required for structural integrity of the C ontainment Structure under DBA conditions. The steel liner and its penetrations establish the leakage limiting boundary of the C ontainment Structure. Maintaining the C ontainment Structure OPERABLE limits the leakage of fission product radioactivity from the C ontainment Structure to the environment.
Surveillance Requirement (SR) 3.6.1.1 leakage rate requirements comply with Reference 1
, as modified by approved exemptions.
The isolation devices for the penetrations in the containment boundary are a part of the containment leak tight barrier. To
maintain this leak tight barrier: a. All penetrations required to be closed during accident conditions are either: 1. capable of being closed by an OPERABLE automatic containment isolation system, or Containment B 3.6.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.1-2 Revision 41 2. closed by manual valves, blind flanges, or de-activated automatic valves secured in their closed
positions, except as provided in Limiting Condition
for Operation (LCO) 3.6.3; b. Each air lock is OPERABLE, except as provided in LCO 3.6.2; c. The equipment hatch is closed and sealed.
APPLICABLE The safety design basis for the Containment Structure is SAFETY ANALYSES that the Containment Structure must withstand the pressures and temperatures of the limiting DBA without exceeding the design
leakage rate.
The DBAs that result in a release of radioactive material within Containment Structure are a loss of coolant accident (LOCA), a
main steam line break (SLB), and a control element assembly (CEA) ejection accident (Reference 2, Chapter 14). In the analysis
of each of these accidents, it is assumed that Containment
Structure is OPERABLE, such that release of fission products to
the environment is controlled by the rate of Containment Structure leakage. The Containment Structure was designed with
an allowable leakage rate of 0.
16% of containment air weight per day (Reference 2, Chapter 5). This leakage rate is defined in Reference 1, as L a: the maximum allowable containment leakage rate at the calculated maximum peak containment pressure (P a) of 49.4 psig, which results from the limiting design basis LOCA (Reference 2, Chapter 14).
Satisfactory leakage rate test results are a requirement for the establishment of Containment Structure OPERABILITY.
The Containment Structure satisfies 10 CFR 50.36(c)(2)(ii), Criterion 3.
LCO Containment OPERABILITY is maintained by limiting leakage to 1.0 L a (276,8 00 SCCM), except prior to the first startup after performing a required Containment Leakage Rate Testing Program leakage test. At this time the applicable leakage limits must
be met.
Containment B 3.6.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.1-3 Revision 2 Compliance with this LCO will ensure a containment configuration, including an equipment hatch, that is
structurally sound and that will limit leakage to those leakage
rates assumed in the safety analysis.
Individual leakage rates specified for the containment air lock (LCO 3.6.2) are not specifically part of the acceptance criteria of Reference 1. Therefore, leakage rates exceeding these individual limits only result in the C ontainment Structure being inoperable when the leakage results in exceeding the overall acceptance criteria of 1.0 L
- a. APPLICABILITY In MODE s 1, 2, 3, and 4, a DBA could cause a release of radioactive material into the C ontainment Structure. In MODE s 5 and 6, the probability and consequences of these events are reduced due to the pressure and temperature limitations of these MODE
- s. Therefore, the C ontainment Structure is not required to be OPERABLE in MODE 5 to prevent leakage of radioactive material from the C ontainment Structure. The requirements for the C ontainment Structure during MODE 6 are addressed in LCO 3.9.3
. ACTIONS A.1 In the event the C ontainment Structure is inoperable, the C ontainment Structure must be restored to OPERABLE status within one hour. The one hour Completion Time provides a period of time to correct the problem commensurate with the importance of maintaining the C ontainment Structure during MODE s 1, 2, 3, and 4. This time period also ensures that the probability of an accident (requiring C ontainment OPERABILITY) occurring during periods when the C ontainment Structure is inoperable is minimal.
B.1 and B.2 If the C ontainment Structure cannot be restored to OPERABLE status within the required Completion Time, the plant must be brought to a MODE in which the LCO does not apply. To achieve this status, the plant 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 plant conditions from full Containment B 3.6.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.1-4 Revision 41 power conditions in an orderly manner and without challenging plant systems.
SURVEILLANCE SR 3.6.1.1 REQUIREMENTS Maintaining the Containment Structure OPERABLE requires compliance with the visual examinations and leakage rate test requirements of the Containment Leakage Rate Testing Program.
Failure to meet leakage limits specified in LCO 3.6.2 and LCO 3.6.3 does not invalidate the acceptability of these overall
leakage determinations unless their contribution to overall Type A, B, and C leakage causes that to exceed limits. As left
leakage, prior to the first startup after performing a required
Containment Leakage Rate Testing Program, is required to be 0.6 L a (166,080 SCCM) for combined Type B and C leakage and 0.75 L a (207,6 00 SCCM) for overall Type A leakage. At all other times between required leakage rate tests, the acceptance criteria is based on an overall Type A leakage limit of 1.0 L a. At 1.0 L a , the offsite dose consequences are bounded by the assumptions of the safety analysis. Surveillance
Requirement Frequencies are as required by Containment Leakage
Rate Testing Program. These periodic testing requirements
verify that the containment leakage rate does not exceed the
leakage rate assumed in the safety analysis.
SR 3.6.1.2 For ungrouted, post-tensioned tendons, this SR ensures that the structural integrity of the Containment Structure will be
maintained in accordance with the provisions of the Concrete
Containment Tendon Surveillance Program. Testing and
Frequency are consistent with the recommendations of Reference 3.
REFERENCES 1. 10 CFR Part 50, Appendix J, "Primary Reactor Containment Leakage Testing for Water-Cooled Power Reactors" Option B, "Performance-Based Requirements" 2. Updated Final Safety Analysis Report (UFSAR)
Containment B 3.6.1 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.1-5 Revision 41 3. American Society of Mechanical Engineers Boiler and Pressure Vessel Code, 1992 Edition through the 1992
Addenda,Section XI, Subsection IWL, Requirements for
Class CC Concrete Components of Light-Water Cooled Power Plants as modified and amended by 10 CFR 50.55a
Containment Air Locks B 3.6.2 B 3.6 CONTAINMENT SYSTEMS
B 3.6.2 Containment Air Locks
BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.2-1 Revision 2 BACKGROUND Containment air locks form part of the containment pressure boundary and provide a means for personnel access during all
MODEs of operation.
Each air lock is nominally a right circular cylinder, 9 feet-9 inches in diameter for the personnel air lock and
5 feet-9 inches in diameter for the emergency air lock, with
a door at each end. The doors are interlocked to prevent
simultaneous opening. During periods when the Containment Structure is not required to be OPERABLE, the door interlock mechanism may be disabled, allowing both doors of an air
lock to remain open for extended periods when frequent
Containment Structure entry is necessary. Each air lock door has been designed and tested to certify its ability to
withstand a pressure in excess of the maximum expected
pressure following a DBA in the Containment Structure. As such, closure of a single door supports the Containment Structure OPERABILITY. Each of the doors contains double gasketed seals and local leakage rate testing capability to
ensure pressure integrity. To effect a leak tight seal, the
air lock design uses pressure seated doors (i.e., an
increase in containment internal pressure results in
increased sealing force on each door).
Each personnel air lock is provided with an alarm in the Control Room that actuates when either door or equalizing valve for a personnel air lock is opened. The alarm senses
door position from a limit switch located on each door and
equalizing valve.
The containment air locks form part of the containment pressure boundary. As such, air lock integrity and leak tightness is essential for maintaining the containment leakage rate within limit in the event of a DBA. Not
maintaining air lock integrity or leak tightness may result
in a leakage rate in excess of that assumed in the unit safety analysis.
Containment Air Locks B 3.6.2 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.2-2 Revision 41 APPLICABLE The DBAs that result in a release of radioactive material SAFETY ANALYSES within the Containment Structure are a LOCA, a main SLB, and a CEA ejection accident (Reference 1, Chapter 14). In the
analysis of each of these accidents, it is assumed that the
Containment Structure is OPERABLE such that release of
fission products to the environment is controlled by the rate of containment leakage. The Containment Structure is designed with an allowable leakage rate of 0.16% of containment air weight per day (Reference 1, Chapter 5).
This leakage rate is defined in 10 CFR Part 50, Appendix J, Option B, as the maximum allowable containment leakage rate
at the calculated peak containment internal pressure, P a (49.4 psig), following a design basis LOCA. This allowable
leakage rate forms the basis for the acceptance criteria
imposed on the SRs associated with the air lock.
The containment air locks satisfy 10 CFR 50.36(c)(2)(ii), Criterion 3.
LCO Each containment air lock forms part of the containment pressure boundary. As part of the containment pressure
boundary, the air lock safety function is related to control
of the containment leakage rate resulting from a DBA. Thus, each air lock's structural integrity and leak tightness, are
essential to the successful mitigation of such an event.
Each air lock is required to be OPERABLE. For the air lock to be considered OPERABLE, the air lock interlock mechanism
must be OPERABLE, the air lock must be in compliance with
the Type B air lock leakage test, and both air lock doors must be OPERABLE. The interlock allows only one air lock door of an air lock to be opened at one time. This
provision ensures that a gross breach of the Containment
Structure does not exist when the Containment Structure is
required to be OPERABLE. Closure of a single door in each
air lock is sufficient to provide a leak tight barrier
following postulated events. Nevertheless, both doors are
kept closed when the air lock is not being used for normal entry into or exit from the Containment Structure.
APPLICABILITY In MODEs 1, 2, 3, and 4, a DBA could cause a release of radioactive material to the containment atmosphere. In
MODEs 5 and 6, the probability and consequences of these Containment Air Locks B 3.6.2 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.2-3 Revision 2 events are reduced due to the pressure and temperature limitations of these MODEs. Therefore, the containment air locks are not required in MODE 5 to prevent leakage of
radioactive material from the Containment Structure. The requirements for the containment air locks during MODE 6 are
addressed in LCO 3.9.3.
ACTIONS The ACTIONS are modified by a Note that allows entry and exit to perform repairs on the affected air lock component.
If the outer door is inoperable, then it may be easily
accessed for most repairs. It is preferred that the air
lock be accessed from inside primary containment by entering
through the other OPERABLE air lock. However, if this is
not practicable, or if repairs on either door must be
performed from the barrel side of the door then it is
permissible to enter the air lock through the OPERABLE door, which means there is a short time during which the
containment boundary is not intact (during access through
the OPERABLE door). The ability to open the OPERABLE door, even if it means the containment boundary is temporarily not
intact, is acceptable because of the low probability of an
event that could pressurize the Containment Structure during the short time in which the OPERABLE door is expected to be
open. After each entry and exit, the OPERABLE door must be
immediately closed. If as low as reasonably achievable (ALARA) conditions permit, entry and exit should be via an OPERABLE air lock.
A second Note has been added to provide clarification that, for this LCO, separate Condition entry is allowed for each
air lock. This is acceptable, since the Required Actions
for each Condition provide appropriate compensatory actions
for each inoperable air lock. Complying with the Required
Actions may allow for continued operation, and a subsequent inoperable air lock is governed by subsequent Condition entry and application of associated Required Actions. A
third Note has been included that requires entry into the
applicable Conditions and Required Actions of LCO 3.6.1, when leakage results in exceeding the overall containment
leakage limit.
Containment Air Locks B 3.6.2 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.2-4 Revision 2 A.1, A.2, and A.3 With one air lock door inoperable in one or more containment air locks, the OPERABLE door must be verified closed (Required Action A.1) in each affected containment air lock.
This ensures that a leak tight containment barrier is
maintained by the use of an OPERABLE air lock door. This action must be completed within one hour. This specified time period is consistent with the ACTIONS of LCO 3.6.1, which requires the Containment Structure be restored to OPERABLE status within one hour.
In addition, the affected air lock penetration must be isolated by locking closed an OPERABLE air lock door within
the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> Completion Time. The 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> Completion Time is
considered reasonable for locking the OPERABLE air lock
door, considering the OPERABLE door of the affected air lock
is being maintained closed.
Required Action A.3 verifies that an air lock with an inoperable door has been isolated by the use of a locked and
closed OPERABLE air lock door. This ensures that an
acceptable containment leakage boundary is maintained. The
Completion Time of once per 31 days is based on engineering
judgment and is considered adequate in view of the low
likelihood of a locked door being mispositioned and other
administrative controls. Required Action A.3 is modified by
a Note that applies to air lock doors located in high
radiation areas and allows these doors to be verified locked
closed by use of administrative means. Allowing
verification by administrative means is considered
acceptable, since access to these areas is typically
restricted. Therefore, the probability of misalignment of
the door, once it has been verified to be in the proper
position, is small.
The Required Actions have been modified by two Notes.
Note 1 ensures that only the Required Actions and associated
Completion Times of Condition C are required if both doors
in the same air lock are inoperable. With both doors in the
same air lock inoperable, an OPERABLE door is not available
to be closed. Required Actions C.1 and C.2 are the
appropriate remedial actions. The exception to Note 1 does Containment Air Locks B 3.6.2 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.2-5 Revision 2 not affect tracking the Completion Time from the initial entry into Condition A; only the requirement to comply with
the Required Actions. Note 2 allows use of the air lock for
entry and exit for seven days under administrative controls if both air locks have an inoperable door. This seven day restriction begins when the second air lock is discovered inoperable. Containment entry may be required to perform Technical Specifications Surveillances and Required Actions, as well as other activities on equipment inside the Containment Structure that are required by Technical Specifications or activities on equipment that support Technical Specifications-required equipment. This Note is not intended to preclude performing other activities (i.e., non-Technical Specifications-required activities) if the Containment Structure was entered, using the inoperable air lock, to perform an allowed activity listed above. This
allowance is acceptable due to the low probability of an
event that could pressurize the Containment Structure during the short time that the OPERABLE door is expected to be
open.
B.1, B.2, and B.3 With an air lock interlock mechanism is inoperable in one or more air locks, the Required Actions and associated
Completion Times are consistent with those specified in
Condition A.
The Required Actions have been modified by two Notes.
Note 1 ensures that only the Required Actions and associated
Completion Times of Condition C are required if both doors
in the same air lock are inoperable. With both doors in the
same air lock inoperable, an OPERABLE door is not available
to be closed. Required Actions C.1 and C.2 are the
appropriate remedial actions. Note 2 allows entry into and exit from the Containment Structure under the control of a dedicated individual stationed at the air lock, to ensure that only one door is opened at a time (i.e., the individual performs the function of the interlock).
Required Action B.3 is modified by a Note that applies to air lock doors located in high radiation areas and allows
these doors to be verified locked closed by use of Containment Air Locks B 3.6.2 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.2-6 Revision 2 administrative means. Allowing verification by administrative means is considered acceptable, since access
to these areas is typically restricted. Therefore, the
probability of misalignment of the door, once it has been
verified to be in the proper position, is small.
C.1, C.2, and C.3 With one or more air locks inoperable for reasons other than those described in Conditions A or B, Required Action C.1 requires action to be initiated immediately to evaluate
previous combined leakage rates using current air lock test
results. An evaluation is acceptable since it is overly
conservative to immediately declare the Containment Structure inoperable if both doors in an air lock have failed a seal test or if the overall air lock leakage is not
within limits. In many instances (e.g., only one seal per
door has failed), the Containment Structure remains OPERABLE, yet only one hour (per LCO 3.6.1) would be provided to restore the air lock door to OPERABLE status
prior to requiring a plant shutdown. In addition, even with
both doors failing the seal test, the overall containment
leakage rate can still be within limits.
Required Action C.2 requires that one door in the affected containment air lock must be verified to be closed. This
action must be completed within the one hour Completion Time. This specified time period is consistent with the
ACTIONS of LCO 3.6.1, which requires that the Containment Structure be restored to OPERABLE status within one hour.
Additionally, the affected air lock(s) must be restored to OPERABLE status within the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> Completion Time. The
specified time period is considered reasonable for restoring
an inoperable air lock to OPERABLE status, assuming that at least one door is maintained closed in each affected air lock.
D.1 and D.2 If the inoperable containment air lock cannot be restored to OPERABLE status within the required Completion Time, the
plant must be brought to a MODE in which the LCO does not
apply. To achieve this status, the plant must be brought to Containment Air Locks B 3.6.2 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.2-7 Revision 2 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 plant
conditions from full power conditions in an orderly manner and without challenging plant systems.
SURVEILLANCE SR 3.6.2.1 REQUIREMENTS Maintaining containment air locks OPERABLE requires compliance with the leakage rate test requirements of the
Containment Leakage Rate Testing Program. This SR reflects
the leakage rate testing requirements with regard to air
lock leakage (Type B leakage tests). The acceptance
criteria were established during initial air lock and the Containment Structure OPERABILITY testing. The periodic testing requirements verify that the air lock leakage does
not exceed the allowed fraction of the overall containment
leakage rate. The Frequency is required by the Containment
Leakage Rate Testing Program.
The SR has been modified by two Notes. Note 1 states that an inoperable air lock door does not invalidate the previous
successful performance of the overall air lock leakage test.
This is considered reasonable since either air lock door is
capable of providing a fission product barrier in the event
of a DBA. Note 2 has been added to this SR requiring the
results to be evaluated against the acceptance criteria of
which is applicable to SR 3.6.1.1. This ensures that air
lock leakage is properly accounted for in determining the
combined Types B and C containment leakage rate.
SR 3.6.2.2 The air lock interlock is designed to prevent simultaneous opening of both doors in a single air lock. Since both the
inner and outer doors of an air lock are designed to
withstand the maximum expected post-accident containment pressure, closure of either door will support the Containment Structure OPERABILITY. Thus, the door interlock feature supports the Containment Support OPERABILITY while the air lock is being used for personnel transit into and
out of the Containment Structure. Periodic testing of this interlock demonstrates that the interlock will function as Containment Air Locks B 3.6.2 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.2-8 Revision 55 designed and that simultaneous opening of the inner and outer doors will not inadvertently occur. Due to the purely
mechanical nature of this interlock, and given that the
interlock mechanism is not normally challenged when the air
lock is used for entry and exit (procedures require strict
adherence to single door opening), this test is only required to be performed every 24 months. The Surveillance Frequency is controlled under the Surveillance Frequency Control Program.
REFERENCES 1. UFSAR
Containment Isolation Valves B 3.6.3 B 3.6 CONTAINMENT SYSTEMS
B 3.6.3 Containment Isolation Valves
BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.3-1 Revision 2 BACKGROUND The containment isolation valves form part of the containment pressure boundary. They provide a means for fluid penetrations (not serving accident consequence limiting systems) to be provided with two isolation barriers that are closed on an automatic isolation signal. These
isolation devices are either passive or active (automatic).
Manual valves, de-activated automatic valves secured in
their closed position (including check valves with flow
through the valve secured), blind flanges, and closed
systems are considered passive devices. Check valves, or
other automatic valves designed to close without operator
action following an accident, are considered active devices.
Two barriers in series are provided for each penetration so
that no single credible failure or malfunction of an active
component can result in a loss of isolation or leakage that
exceeds limits assumed in the safety analysis. One of these
barriers may be a closed system.
Containment isolation occurs upon receipt of a high containment pressure signal. The containment isolation
signal closes automatic containment isolation valves in fluid penetrations, not required for operation of Engineered Safety Feature (ESF) systems, in order to prevent leakage of radioactive material. Upon actuation of safety injection, automatic containment isolation valves also isolate systems
not required for the Containment Structure or Reactor Coolant System (RCS) heat removal. Other penetrations are
isolated by the use of valves in the closed position or
blind flanges. As a result, the containment isolation
valves (and blind flanges) help ensure that the containment
atmosphere will be isolated in the event of a release of
radioactive material to containment atmosphere from the RCS following a DBA.
The OPERABILITY requirements for containment isolation valves help ensure that the Containment Structure is isolated within the time limits assumed in the safety
analysis. Therefore, the OPERABILITY requirements provide
assurance that the Containment Structure function assumed in the accident analysis will be maintained.
Containment Isolation Valves B 3.6.3 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.3-2 Revision 32 APPLICABLE The containment isolation valve LCO was derived from the SAFETY ANALYSES assumptions related to minimizing the loss of reactor coolant inventory and establishing the containment boundary
during major accidents. As part of the containment
boundary, containment isolation valve OPERABILITY supports leak tightness of the Containment Structure. Therefore, the safety analysis of any event requiring isolation of the
Containment Structure is applicable to this LCO.
The DBAs that result in a release of radioactive material within the Containment Structure are a LOCA, a main SLB, and
a CEA ejection accident. In the analysis for each of these
accidents, it is assumed that containment isolation valves
are either closed or function to close within the required
isolation time following event initiation. This ensures
that potential paths to the environment through containment
isolation valves (including containment purge valves) are
minimized. The safety analysis assumes that the purge
valves are closed at event initiation.
The DBA analysis assumes that, within 60 seconds after the accident, isolation of the Containment Structure is complete
and leakage terminated except for the design leakage rate, L a. The containment isolation total response time of 60 seconds includes signal delay, diesel generator startup (for loss of offsite power), and containment isolation valve
The containment isolation valves satisfy 10 CFR 50.36(c)(2)(ii), Criterion 3.
LCO Containment isolation valves form a part of the Containment Structure boundary. The containment isolation valve safety
function is related to minimizing the loss of reactor
coolant inventory and establishing the Containment Structure
boundary during a DBA. The valves covered by this LCO are listed in Reference 1.
The automatic power operated isolation valves are required to have isolation times within limits and to actuate on an
automatic isolation signal. These valves are listed with their associated stroke times in Reference 2.
Containment Isolation Valves B 3.6.3 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.3-3 Revision 2 The normally closed isolation valves are considered OPERABLE when manual valves are closed, automatic valves are
de-activated and secured in their closed position, blind
flanges are in place, and closed systems are intact. These
passive isolation valves or devices are those listed in Reference 1.
This LCO provides assurance that the containment isolation valves will perform their designed safety functions to
minimize the loss of reactor coolant inventory and establish the Containment Structure boundary during accidents.
APPLICABILITY In MODEs 1, 2, 3, and 4, a DBA could cause a release of radioactive material to the Containment Structure. In MODEs 5 and 6, the probability and consequences of these events are reduced due to the pressure and temperature
limitations of these MODEs. Therefore, the containment isolation valves are not required to be OPERABLE in MODE 5.
The requirements for containment isolation valves during MODE 6 are addressed in LCO 3.9.3.
ACTIONS The ACTIONS are modified by a Note allowing penetration flow paths to be unisolated intermittently under administrative
controls. These administrative controls consist of stationing a dedicated operator at the valve controls who is in continuous communication with the Control Room. In this way, the penetration can be rapidly isolated when a need for containment isolation is indicated.
A second Note has been added to provide clarification that, for this LCO, separate Condition entry is allowed for each
penetration flow path. This is acceptable, since the
Required Actions for each Condition provide appropriate
compensatory actions for each inoperable containment
isolation valve. Complying with the Required Actions may
allow for continued operation, and subsequent inoperable
containment isolation valves are governed by subsequent
Condition entry and application of associated Required
Actions.
The ACTIONS are further modified by a third Note, which ensures that appropriate remedial actions are taken, if Containment Isolation Valves B 3.6.3 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.3-4 Revision 2 necessary, if the affected systems are rendered inoperable by an inoperable containment isolation valve.
The fourth Note has been added that requires entry into the applicable Conditions and Required Actions of LCO 3.6.1, when leakage results in exceeding the overall containment leakage limit.
The fifth Note allows the shutdown cooling isolation valves to be opened when RCS temperature is
< 300°F to establish shutdown cooling flow. This Note is required for Operation in MODE 4 to allow shutdown cooling to be established.
A.1 and A.2 In the event one containment isolation valve in one or more penetration flow paths is inoperable, the affected
penetration flow path must be isolated. The method of
isolation must include the use of at least one isolation
barrier that cannot be adversely affected by a single active
failure. Isolation barriers that meet this criterion are a
closed and de-activated automatic containment isolation
valve, a closed manual valve, a blind flange, and a check
valve with flow through the valve secured. For penetrations
isolated in accordance with Required Action A.1, the device
used to isolate the penetration should be the closest
available one to the Containment Structure. Required Action A.1 must be completed within the four hour Completion Time. The four hour Completion Time is reasonable, considering the time required to isolate the penetration and
the relative importance of supporting the Containment Structure OPERABILITY during MODEs 1, 2, 3, and 4.
For affected penetration flow paths that cannot be restored to OPERABLE status within the four hour Completion Time and that have been isolated in accordance with Required Action A.1, the affected penetration flow paths must be verified to be isolated on a periodic basis. This is
necessary to ensure that containment penetrations required
to be isolated following an accident and no longer capable
of being automatically isolated, will be in the isolation position should an event occur. This Required Action does
not require any testing or device manipulation. Rather, it Containment Isolation Valves B 3.6.3 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.3-5 Revision 2 involves verification, through a system walkdown, that those isolation devices outside the Containment Structure and capable of being mispositioned are in the correct position.
The Completion Time of "once per 31 days for isolation
devices outside Containment" is appropriate considering the fact that the devices are operated under administrative controls and the probability of their misalignment is low.
For the isolation devices inside the Containment Structure, the time period specified as "prior to entering MODE 4 from
MODE 5 if not performed within the previous 92 days" is
based on engineering judgment and is considered reasonable
in view of the inaccessibility of the isolation devices and
other administrative controls that will ensure that
isolation device misalignment is an unlikely possibility.
Condition A has been modified by a Note indicating that this Condition is only applicable to those penetration flow paths
with two containment isolation valves and not a closed
system. For penetration flow paths with one or more
containment isolation valves and a closed system, Condition C provides appropriate actions.
Required Action A.2 is modified by a Note that applies to isolation devices located in high radiation areas and allows
these devices to be verified closed by use of administrative
means. Allowing verification by administrative means is
considered acceptable, since access to these areas is
typically restricted. Therefore, the probability of
misalignment of these devices, once they have been verified
to be in the proper position, is small.
B.1 With two containment isolation valves in one or more penetration flow paths inoperable, the affected penetration flow path must be isolated within one hour. The method of isolation must include the use of at least one isolation barrier that cannot be adversely affected by a single active
failure. Isolation barriers that meet this criterion are a
closed and de-activated automatic valve, a closed manual
valve, and a blind flange. The one hour Completion Time is consistent with the ACTIONS of LCO 3.6.1. In the event the
affected penetration is isolated in accordance with Required Containment Isolation Valves B 3.6.3 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.3-6 Revision 2 Action B.1, the affected penetration must be verified to be isolated on a periodic basis per Required Action A.2, which
remains in effect. This periodic verification is necessary
to assure leak tightness of the Containment Structure and that penetrations requiring isolation following an accident
are isolated. The Completion Time of once per 31 days for verifying each affected penetration flow path is isolated, is appropriate, considering the fact that the valves are operated under administrative controls and the probability of their misalignment is low.
Condition B is modified by a Note indicating this Condition is only applicable to penetration flow paths with two
containment isolation valves. Condition A of this LCO
addresses the condition of one containment isolation valve
inoperable in this type of penetration flow path.
C.1 and C.2 With one or more containment isolation valves inoperable in one or more penetration flow paths, the inoperable valves must be restored to OPERABLE status or the affected
penetration flow path must be isolated. The method of
isolation must include the use of at least one isolation
barrier that cannot be adversely affected by a single active
failure. Isolation barriers that meet this criterion are a
closed and de-activated automatic valve, a closed manual
valve, and a blind flange. A check valve may not be used to
isolate the affected penetration. Required Action C.1 must
be completed within the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> Completion Time. The
specified time period is reasonable, considering the
relative stability of the closed system (hence, reliability)
to act as a penetration isolation boundary and the relative
importance of supporting the Containment Structure OPERABILITY during MODEs 1, 2, 3, and 4. In the event the affected penetration is isolated in accordance with Required
Action C.1, the affected penetration flow path must be
verified to be isolated on a periodic basis. This is
necessary to assure leak tightness of the Containment Structure and that containment penetrations requiring isolation following an accident are isolated. The
Completion Time of once per 31 days for verifying that each
affected penetration flow path is isolated, is appropriate Containment Isolation Valves B 3.6.3 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.3-7 Revision 32 considering the valves are operated under administrative controls and the probability of their misalignment is low.
Condition C is modified by a Note indicating that this Condition is only applicable to those penetration flow paths
with one or more containment isolation valves and a closed system. This Note is necessary since this Condition is written to specifically address those penetration flow paths
in a closed system. Containment isolation valves and their
associated penetration numbers are given in Reference 1.
The penetrations with closed systems are listed below.
Penetration No.
Function 1B Containment Vent Header to Waste Gas 16 Component Cooling Water Inlet 17A Steam Generator Surface Blowdown 17B Steam Generator Surface Blowdown 18 Component Cooling Water Outlet 19A Instrument Air 20A Nitrogen Supply 20B Nitrogen Supply 20C Nitrogen Supply 21 Auxiliary Feedwater 22 Auxiliary Feedwater 23 Reactor Coolant Drain Tank Drains 24 Oxygen Sample Line
25 Service Water Inlet 26 Service Water Inlet 27 Service Water Inlet 28 Service Water Inlet 29 Service Water Return 30 Service Water Return 31 Service Water Return 32 Service Water Return 33 Main Feedwater 34 Main Feedwater 35 Main Steam 36 Main Steam 38 Demineralized Water
43A Steam Generator Bottom Blowdown 43B Steam Generator Bottom Blowdown 44 Fire Protection Containment Isolation Valves B 3.6.3 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.3-8 Revision 55 Required Action C.2 is modified by a Note that applies to valves and blind flanges, located in high radiation areas, and allows these devices to be verified closed by use of
administrative means. Allowing verification by
administrative means is considered acceptable, since access to these areas is typically restricted. Therefore, the probability of misalignment of these valves, once they have
been verified to be in the proper position, is small.
D.1 and D.2 If the Required Actions and associated Completion Times are not met, the plant must be brought to a MODE in which the
LCO does not apply. To achieve this status, the plant 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 plant conditions from full power conditions in an orderly manner and without challenging plant systems.
SURVEILLANCE SR 3.6.3.1 REQUIREMENTS This SR ensures that the containment vent valves are closed as required, or, if open, open for an allowable reason. If
a containment vent valve is open in violation of this SR, the valve is considered inoperable. If the inoperable valve
is not otherwise known to have excessive leakage when
closed, it is not considered to have leakage outside of
limits. The SR is not required to be met when the
containment vent valves are open for pressure control, ALARA or air quality considerations for personnel entry, or for surveillance tests that require the valves to be open. The
containment vent valves are capable of closing in the
environment, following a LOCA. Therefore, these valves are
allowed to be open for limited periods of time. The Surveillance Frequency is controlled under the Surveillance Frequency Control Program.
SR 3.6.3.2 This SR requires verification that each containment isolation manual valve and blind flange located outside the
Containment Structure, and not locked, sealed, or otherwise Containment Isolation Valves B 3.6.3 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.3-9 Revision 55 secured, and required to be closed during accident conditions is closed. The SR helps to ensure that post-
accident leakage of radioactive fluids or gases outside the
containment boundary is within design limits. This SR does
not require any testing or valve manipulation. Rather, it
involves verification, through a system walkdown, that those containment isolation valves outside the Containment Structure and capable of being mispositioned are in the
correct position. The Surveillance Frequency is controlled under the Surveillance Frequency Control Program.
Containment isolation valves that are open under
administrative controls are not required to meet the SR
during the time the valves are open. This SR does not apply
to valves that are locked, sealed, or otherwise secured in
the closed position, since these were verified to be in the
correct position upon locking, sealing, or securing.
The Note applies to valves and blind flanges located in high radiation areas and allows these devices to be verified
closed by use of administrative means. Allowing
verification by administrative means is considered
acceptable, since access to these areas is typically
restricted during MODEs 1, 2, 3, 4 and for ALARA reasons.
Therefore, the probability of misalignment of these
containment isolation valves, once they have been verified
to be in the proper position, is small.
SR 3.6.3.3 This SR requires verification that each containment isolation manual valve and blind flange located inside the
Containment Structure, and not locked, sealed, or otherwise
secured, and required to be closed during accident
conditions is closed. The SR helps to ensure that post-
accident leakage of radioactive fluids or gases outside the containment boundary is within design limits. For containment isolation valves inside the Containment
Structure, the Frequency of "prior to entering MODE 4 from
MODE 5 if not performed within the previous 92 days" is
appropriate, since these containment isolation valves are
operated under administrative controls and the probability
of their misalignment is low. Containment isolation valves
that are open under administrative controls are not required
to meet the SR during the time that they are open. This SR Containment Isolation Valves B 3.6.3 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.3-10 Revision 55 does not apply to valves that are locked, sealed, or otherwise secured in the closed position, since these were
verified to be in the correct position upon locking, sealing, or securing.
The Note allows valves and blind flanges located in high radiation areas to be verified closed by use of administrative means. Allowing verification by
administrative means is considered acceptable, since access
to these areas is typically restricted during MODEs 1, 2, and 3 for ALARA reasons. Therefore, the probability of
misalignment of these containment isolation valves, once
they have been verified to be in their proper position, is
small.
SR 3.6.3.4 Verifying that the isolation time of each automatic power operated containment isolation valve is within limits is
required to demonstrate OPERABILITY. The isolation time
test, ensures the valve will isolate in a time period less
than or equal to that assumed in the safety analysis. The
isolation time and Frequency of this SR are in accordance
with the Inservice Testing Program. The isolation time
limits are contained in Reference 2.
SR 3.6.3.5 Automatic containment isolation valves close on an isolation signal [containment isolation signal Channels A or B, or
safety injection actuation signal (SIAS) Channels A or B] to
prevent leakage of radioactive material from the Containment
Structure following a DBA. This SR ensures each automatic
containment isolation valve will actuate to its isolation
position on a containment isolation actuation signal. This
surveillance test is not required for valves that are locked, sealed, or otherwise secured in the required position under administrative controls. The Surveillance Frequency is controlled under the Surveillance Frequency Control Program.
REFERENCES 1. UFSAR, Chapter 5, "Structures", Figure 5-10 2. UFSAR, Chapter 5, "Structures", Table 5-3
Containment Pressure B 3.6.4 B 3.6 CONTAINMENT SYSTEMS
B 3.6.4 Containment Pressure
BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.4-1 Revision 47 BACKGROUND The containment pressure is limited during normal operation to preserve the initial conditions assumed in the accident
analyses for a LOCA or main SLB. These limits also prevent
the containment pressure from exceeding the containment design negative pressure differential, with respect to the outside atmosphere in the event of the Containment Structure
being sealed during low barometric pressure and high
temperature, then being exposed to a concurrent cooling of
containment atmosphere and a barometric pressure rise.
Containment pressure is a process variable that is monitored and controlled. The containment pressure limits are derived
from the input conditions used in the containment functional
analyses and the containment structure external pressure
analysis. Should operation occur above the upper limits
coincident with a DBA, post-accident containment pressures
could exceed calculated values. Should containment closure
or integrity be set below the lower limits, the external
pressure limits may be exceeded during barometric pressure changes. APPLICABLE Containment internal pressure is an initial condition used SAFETY ANALYSES in the DBA analyses to establish the maximum peak containment internal pressure. The limiting DBA considered
for determining the maximum containment internal pressure is
the LOCA. A LOCA at 102% RATED THERMAL POWER and + 1.0 psig initial containment pressure results in the highest
calculated internal containment pressure (P a) below the internal design pressure of 50.0 psig. The postulated DBAs are analyzed assuming degraded containment ESF systems (i.e., assuming the loss of one ESF bus, which is the worst
case single active failure, resulting in one train of the
containment spray and one train of the containment coolers
being rendered inoperable). It is this maximum containment
pressure that is used to ensure that the licensing basis
dose limitations are met.
The initial pressure condition used in the containment analysis was 15.7 psia (1.0 psig). The LCO limit of 1.0 psig ensures that, in the event of an accident, the Containment Pressure B 3.6.4 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.4-2 Revision 47 maximum accident design pressure for the Containment Structure, 50 psig, is not exceeded. If a LOCA occurred
while the containment internal pressure was at the LCO value
of 1.0 psig, a total pressure below the design value of 50 psig would result.
Containment pressure satisfies 10 CFR 50.36(c)(2)(ii), Criterion 2.
LCO Maintaining containment pressure less than or equal to the LCO upper pressure limit ensures that, in the event of a
DBA, the resultant peak containment accident pressure will
remain below the containment design pressure. Maintaining
containment pressure greater than or equal to the LCO lower
pressure limit, ensures that the Containment Structure will
not exceed the design negative pressure differential following the inadvertent actuation of containment spray.
APPLICABILITY In MODEs 1, 2, 3, and 4, a DBA could cause a release of radioactive material to the Containment Structure. Since
maintaining containment pressure within limits is essential
to ensure initial conditions assumed in the accident
analysis are maintained, the LCO is applicable in MODEs 1, 2, 3, and 4.
In MODEs 5 and 6, the probability and consequences of these events are reduced due to the pressure and temperature
limitations of these MODEs. Therefore, maintaining
containment pressure within the limits of the LCO is not required in MODEs 5 or 6.
ACTIONS A.1 When containment pressure is not within the limits of the LCO, containment pressure must be restored to within these
limits, within one hour. The Required Action is necessary
to return operation to within the bounds of the containment
analysis. The one hour Completion Time is consistent with
the ACTIONS of LCO 3.6.1 which requires that the Containment
Structure be restored to OPERABLE status within one hour.
Containment Pressure B 3.6.4 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.4-3 Revision 55 B.1 and B.2 If containment pressure cannot be restored to within limits within the required Completion Time, the plant must be
brought to a MODE in which the LCO does not apply. To
achieve this status, the plant 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 plant conditions from full
power conditions in an orderly manner, and without challenging plant systems.
SURVEILLANCE SR 3.6.4.1 REQUIREMENTS Verifying that containment pressure is within limits ensures that operation remains within the limits assumed in the
accident analysis. The Surveillance Frequency is controlled under the Surveillance Frequency Control Program.
REFERENCES None
Containment Air Temperature B 3.6.5 B 3.6 CONTAINMENT SYSTEMS
B 3.6.5 Containment Air Temperature
BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.5-1 Revision 2 BACKGROUND The Containment Structure serves to contain radioactive material that may be released from the reactor core following a DBA. The Containment Structure average air temperature is limited during normal operation to preserve the initial conditions assumed in the accident analyses for a LOCA or main SLB.
The containment average air temperature limit is derived from the input conditions used in the containment functional
analyses and the Containment Structure external pressure analyses. This LCO ensures that initial conditions assumed
in the analysis of containment response to a DBA, are not violated during unit operations. The total amount of energy
to be removed from Containment Structure by the containment spray and containment cooling during post-accident conditions is dependent on the energy released to the
Containment Structure due to the event, as well as the initial containment temperature and pressure. The higher
the initial temperature, the more energy that must be
removed, resulting in a higher peak containment pressure and
temperature. Exceeding containment design pressure may
result in leakage greater than that assumed in the accident
analysis (Reference 1). Operation with containment
temperature in excess of the LCO limit violates an initial condition assumed in the accident analysis.
APPLICABLE Containment average air temperature is an initial condition SAFETY ANALYSES used in the DBA analyses that establishes the containment environmental qualification operating envelope for both pressure and temperature. The limit for containment average
air temperature ensures that operation is maintained within
the assumptions used in the DBA analysis for Containment.
The accident analyses and evaluations considered both LOCAs
and main SLBs for determining the maximum peak containment pressures and temperatures. The worst case LOCA generates
larger mass and energy releases than the worst case main SLB. Thus, the LOCA event bounds the main SLB event from the containment peak pressure and temperature standpoint.
The initial pre-accident temperature inside the Containment Structure was assumed to be 120°F (Reference 1).
Containment Air Temperature B 3.6.5 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.5-2 Revision 2 The initial containment average air temperature condition of 120°F resulted in a maximum vapor temperature described in Reference 1. The consequence of exceeding the design temperature for extended periods may be the potential for degradation of the containment structure under accident loads.
Containment average air temperature satisfies 10 CFR 50.36(c)(2)(ii), Criterion 2.
LCO During a DBA, with an initial containment average air temperature less than or equal to the LCO temperature limit, the resultant peak accident temperature is maintained below
the containment design temperature. As a result, the
ability of the Containment Structure to perform its function is ensured.
APPLICABILITY In MODEs 1, 2, 3, and 4, a DBA could cause a release of radioactive material to the Containment Structure. In MODEs 5 and 6, the probability and consequences of these events are reduced due to the pressure and temperature
limitations of these MODEs. Therefore, maintaining containment average air temperature within the limit is not required in MODEs 5 or 6.
ACTIONS A.1 When containment average air temperature is not within the limit of the LCO, it must be restored to within limit, within eight hours. This Required Action is necessary to return operation to within the bounds of the containment
analysis. The eight hour Completion Time is acceptable considering the sensitivity of the analysis to variations in
this parameter and provides sufficient time to correct minor
problems.
B.1 and B.2 If the containment average air temperature cannot be restored to within its limit, within the required Completion Time, the plant must be brought to a MODE in which the LCO
does not apply. To achieve this status, the plant 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 Containment Air Temperature B 3.6.5 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.5-3 Revision 55 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 plant conditions from full power conditions in an orderly manner and without challenging plant systems.
SURVEILLANCE SR 3.6.5.1 REQUIREMENTS Verifying that containment average air temperature is within the LCO limit ensures that containment operation remains
within the limit assumed for the containment analyses. In
order to determine the containment average air temperature, an arithmetic average is calculated using measurements taken
from the containment dome [1(2)-TI-5309] and the containment
reactor cavity [1(2)-TI-5311] temperature indicators
selected to provide a representative sample of the overall
containment atmosphere. The Surveillance Frequency is controlled under the Surveillance Frequency Control Program.
REFERENCES 1. UFSAR, Section 14.20, "Containment Response" Containment Spray and Cooling Systems B 3.6.6 B 3.6 CONTAINMENT SYSTEMS
B 3.6.6 Containment Spray and Cooling Systems
BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.6-1 Revision 2 BACKGROUND The Containment Spray and Cooling Systems provide containment atmosphere cooling to limit post-accident pressure and temperature in the Containment Structure to less than the design values. Reduction of containment pressure and the iodine removal capability of the spray, reduce the release of fission product radioactivity from the Containment Structure to the environment, in the event of a DBA, to within limits. The Containment Spray and Cooling Systems are designed to the requirements in Reference 1, Appendix 1C, Criteria, 58, 59, 60, 61, 62, 63, 64, and 65.
The Containment Spray and Cooling Systems are ESF systems.
They are designed to ensure that the heat removal capability
required during the post-accident period can be attained.
The Containment Spray and Cooling Systems provide redundant methods to limit and maintain post-accident conditions to less than the containment design values.
Containment Spray System The Containment Spray System consists of two separate trains of equal capacity, each of sufficient capacity to supply
approximately 50% of the design cooling requirement. Each
train includes a containment spray pump, spray headers, nozzles, valves, and piping. Each train is powered from a
separate ESF bus. The refueling water tank (RWT) supplies
borated water to the containment spray during the injection
phase of operation. In the recirculation mode of operation, containment spray pump suction is transferred from the RWT
to the containment sump(s). Each spray system flow path
from the containment sump will be via an OPERABLE shutdown
cooling heat exchanger.
The Containment Spray System provides a spray of cold borated water into the upper regions of the Containment Structure to reduce containment pressure and temperature and to reduce the concentration of fission products in the
containment atmosphere during a DBA. The RWT solution
temperature is an important factor in determining the heat
removal capability of the Containment Spray System during
the injection phase. In the recirculation mode of Containment Spray and Cooling Systems B 3.6.6 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.6-2 Revision 2 operation, heat is removed from the containment sump water by the shutdown cooling heat exchangers. Each train of the
Containment Spray System provides adequate spray coverage to
meet 50% of the system design requirements for containment
heat removal and 100% of the iodine removal design bases.
The Containment Spray System is actuated either automatically by a containment spray actuation signal coincident with a SIAS or manually. An automatic actuation starts the two containment spray pumps, and begins the injection phase. The containment spray header isolation
valves open upon a containment spray actuation signal. A manual actuation of the Containment Spray System is
available on the main control board to begin the same
sequence. The injection phase continues until an RWT low level signal is received. The low level for the RWT generates a recirculation actuation signal that aligns valves from the containment spray pump suction to the
containment sump. The Containment Spray System in
recirculation mode maintains an equilibrium temperature
between the containment atmosphere and the recirculated sump
water. Operation of the Containment Spray System in the
recirculation mode is controlled by the operator in
accordance with the Emergency Operating Procedures.
Containment Cooling System Two trains of containment cooling, each of sufficient capacity to supply approximately 67% of the design cooling
requirement, are provided. Two trains with two fan units
each are supplied with cooling water from a separate train
of service water cooling. Three of the four fans are
required to furnish the design cooling capacity. Air is
drawn into the coolers through the fans and discharged
throughout the Containment Structure.
In post-accident operation following a SIAS, all four Containment Cooling System fans are designed to start
automatically in slow speed. Cooling is supplied by the
service water cooled coils. The temperature of the service
water is an important factor in the heat removal capability of the fan units.
Containment Spray and Cooling Systems B 3.6.6 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.6-3 Revision 39 APPLICABLE The Containment Spray and Cooling Systems limit the SAFETY ANALYSES temperature and pressure that could be experienced following a DBA. The limiting DBAs considered relative to containment
temperature and pressure are LOCA and main SLB. The DBA, LOCA, and main SLB are analyzed using computer codes
designed to predict the resultant containment pressure and temperature transients. No DBAs are assumed to occur simultaneously or consecutively. The postulated DBAs are
analyzed with regard to containment ESF systems, assuming
the loss of one ESF bus, which is the worst case single
active failure, resulting in one train of the Containment
Spray System and one train of the Containment Cooling System
being rendered inoperable.
The analysis and evaluation show that under the worst case scenario, the highest peak containment pressure and
temperature are within the design. (See the Bases for
Specifications 3.6.4 and 3.6.5 for a detailed discussion.)
The analyses and evaluations assume a power level of 2754 MWt, one containment spray train and one containment cooling train operating, and initial (pre-accident)
conditions of 120°F and 16.5 psia. The analyses also
assumes a response time delayed initiation, in order to
provide a conservative calculation of peak containment
pressure and temperature responses.
The modeled Containment Spray System actuation from the containment analysis is based upon a response time
associated with exceeding the Containment High-High pressure
setpoint coincident with an SIAS to achieve full flow
through the containment spray nozzles. The Containment
Spray System total response time of 62.9 seconds for a main
steam line break and 70.9 seconds for a LOCA, includes
diesel generator startup (for loss of offsite power), sequencing equipment onto the emergency bus, containment spray pump startup, and spray line filling (Reference 1, Chapter 7).
The performance of the containment cooling train for post-accident conditions is given in Reference 1, Chapter 6. The
results of the analysis, is that each train can provide
approximately 67% of the required peak cooling capacity
during the post-accident condition. The train post-accident Containment Spray and Cooling Systems B 3.6.6 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.6-4 Revision 15 cooling capacity under varying containment ambient conditions, required to perform the accident analyses, is
also shown in Reference 1, Chapter 6.
The modeled Containment Cooling System actuation from the containment analysis, is based upon the unit specific response time associated with exceeding the SIAS to achieve full Containment Cooling System air and safety grade cooling
water flow.
The Containment Spray and Cooling Systems satisfy 10 CFR 50.36(c)(2)(ii), Criterion 3.
LCO During a DBA, a minimum of one containment cooling train and one containment spray train, is required to maintain the
containment peak pressure and temperature, below the design
limits (Reference 1, Chapter 6). Additionally, one
containment spray train is also required to remove iodine
from the containment atmosphere and maintain concentrations
below those assumed in the safety analysis. To ensure that
these requirements are met, two containment spray trains and
two containment cooling trains (all four coolers) must be
OPERABLE. Therefore, in the event of an accident, the
minimum requirements are met, assuming that the worst case
single active failure occurs.
Each Containment Spray System includes a spray pump, spray headers, nozzles, valves, piping, instruments, and controls
to ensure an OPERABLE flow path capable of taking suction
from the RWT upon an ESF actuation signal and automatically transferring suction to the containment sump. Each spray system flow path from the containment sump will be via an
OPERABLE shutdown cooling heat exchanger.
Each Containment Cooling System includes cooling coils, dampers, fans, instruments, and controls to ensure an OPERABLE flow path.
APPLICABILITY In MODEs 1, 2, and 3, a DBA could cause a release of radioactive material to the Containment Structure and an
increase in containment pressure and temperature, requiring
the operation of the containment spray trains and
containment cooling trains.
Containment Spray and Cooling Systems B 3.6.6 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.6-5 Revision 52 The Containment Spray System is only required to be OPERABLE in MODE 3 with pressurizer pressure 1750 psia.
In MODE 3 with pressurizer pressure
< 1750 psia, and in MODEs 4, 5, and 6, the probability and consequences of these events are reduced due to the pressure and temperature limitations of these MODEs. Thus, the Containment Spray
System is not required to be OPERABLE in MODE 3 with pressurizer pressure
< 1750 psia, and the Containment Spray and Cooling Systems are not required to be OPERABLE in MODEs 4, 5, and 6.
ACTIONS A.1 With one containment spray train inoperable, the inoperable containment spray train must 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 />. In this Condition, the remaining OPERABLE
spray and cooling trains are adequate to perform the iodine
removal and containment cooling functions. 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 redundant heat
removal capability afforded by the Containment Spray System, reasonable time for repairs, and the low probability of a
DBA occurring during this period.
B.1 With one required containment cooling train inoperable, the inoperable containment cooling train must be restored to
OPERABLE status within seven days. The remaining OPERABLE
containment spray and cooling components are capable of providing greater than 100% of the heat removal needs (for the condition of one containment cooling train inoperable) after an accident. The seven day Completion Time was
developed based on the same reasons as those for Required Action A.1.
C.1 and C.2 With two required containment spray trains inoperable, at least one of the required containment spray trains must be restored to OPERABLE status within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. Both trains of containment cooling must be OPERABLE or Condition F is also entered. The Condition is modified by a Note stating it is not applicable if the second containment spray train is Containment Spray and Cooling Systems B 3.6.6 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.6-6 Revision 52 intentionally declared inoperable. The Condition does not apply to voluntary removal of redundant systems or components from service. The Condition is only applicable if one train is inoperable for any reason and the second train is discovered to be inoperable, or if both trains are discovered to be inoperable at the same time. In addition, LCO 3.7.11, CREVS, must be verified to be met within one hour. The OPERABLE containment cooling system components are capable of providing greater than 100% of the heat removal needs after an accident. The Completion Time is based on Reference 2 which demonstrated that the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> Completion Time is acceptable based on the redundant heat removal capabilities afforded by the Containment Cooling System, the iodine removal capability of the Control Room Emergency Ventilation System, the infrequent use of the Required Action, and the small incremental effect on plant risk. D.1 With two required containment cooling trains inoperable, one of the required containment cooling trains must 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 remaining OPERABLE
containment spray components provide iodine removal
capabilities and are capable of providing at least 100% of
the heat removal needs after an accident. The 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />
Completion Time was developed taking into account the
redundant heat removal capabilities afforded by combinations
of the Containment Spray and Cooling Systems, the iodine
removal function of the Containment Spray System, and the
low probability of a DBA occurring during this period.
E.1 and E.2 If the Required Actions and associated Completion Times are not met, the plant must be brought to a MODE in which the LCO does not apply. To achieve this status, the plant 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 4
within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. The allowed Completion Times are
reasonable, based on operating experience, to reach the
required plant conditions from full power conditions in an
orderly manner and without challenging plant systems.
Containment Spray and Cooling Systems B 3.6.6 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.6-7 Revision 55 F.1 With any combination of three or more Containment Spray and Cooling Systems trains inoperable, the unit is in a
condition outside the accident analysis. Therefore, LCO 3.0.3 must be entered immediately.
SURVEILLANCE SR 3.6.6.1 REQUIREMENTS Verifying the correct alignment for manual, power-operated, and automatic valves in the containment spray flow path
provides assurance that the proper flow paths will exist for
Containment Spray System operation. This SR does not apply
to valves that are locked, sealed, or otherwise secured in
position since these were verified to be in the correct
position prior to being secured. This SR also does not
apply to valves that cannot be inadvertently misaligned, such as check valves. This SR does not require any testing
or valve manipulation. Rather, it involves verifying, through a system walkdown, that those valves outside the
Containment Structure and capable of potentially being
mispositioned are in the correct position.
The Surveillance Frequency is controlled under the Surveillance Frequency Control Program.
SR 3.6.6.2 Starting each containment cooling train fan unit from the Control Room and operating it for 15 minutes ensures that all trains are OPERABLE and that all associated controls are
functioning properly. It also ensures that blockage, fan or motor failure, or excessive vibration can be detected and corrective action taken. The Surveillance Frequency is controlled under the Surveillance Frequency Control Program.
SR 3.6.6.3 Verifying a service water flow rate of 2000 gpm to each cooling unit when the full flow service water outlet valves
are fully open provides assurance that the design flow rate
assumed in the safety analyses will be achieved (Reference 1, Chapter 7). The Surveillance Frequency is controlled under the Surveillance Frequency Control Program.
Containment Spray and Cooling Systems B 3.6.6 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.6-8 Revision 55 SR 3.6.6.4 Verifying that each containment spray pumps developed head at the flow test point is greater than or equal to the
required developed head ensures that spray pump performance
has not degraded during the cycle. Flow and differential
pressure are normal tests of centrifugal pump performance required by Reference 3. Since the containment spray pumps cannot be tested with flow through the spray headers, they are tested on recirculation flow. This test confirms one
point on the pump design curve and is indicative of overall
performance. Such inservice inspections confirm component
OPERABILITY, trend performance, and detect incipient
failures by indicating abnormal performance. The Frequency
of this SR is in accordance with the Inservice Testing
Program.
SR 3.6.6.5 and SR 3.6.6.6 These SRs verify that each automatic containment spray valve actuates to its correct position and that each containment
spray pump starts upon receipt of an actual or simulated
actuation signal (i.e., the appropriate Engineered Safety
Feature Actuation System signal). This SR is not required
for valves that are locked, sealed, or otherwise secured in
the required position under administrative controls. The Surveillance Frequency is controlled under the Surveillance Frequency Control Program.
The surveillance test of containment sump isolation valves is also required by SR 3.5.2.5. A single surveillance test
may be used to satisfy both requirements.
SR 3.6.6.7 This SR verifies that each containment cooling train actuates upon receipt of an actual or simulated actuation signal (i.e., the appropriate Engineered Safety Feature Actuation System signal). The Surveillance Frequency is controlled under the Surveillance Frequency Control Program.
SR 3.6.6.8 With the containment spray inlet valves closed and the spray header drained of any solution, low pressure air or smoke Containment Spray and Cooling Systems B 3.6.6 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.6-9 Revision 55 can be blown through check valve bonnets. Performance of this SR demonstrates that each spray nozzle is unobstructed
and provides assurance that spray coverage of the
Containment Structure during an accident is not degraded.
Due to the passive design of the nozzle, a test after
maintenance that could result in nozzle blockage is considered adequate. Maintenance that could result in nozzle blockage is generally loss of foreign material
control or a flow of borated water through a nozzle. Should
either of these events occur, a supervisory evaluation will
be required to determine whether nozzle blockage is a possible result of the event.
REFERENCES 1. UFSAR 2. WCAP-16125-NP-A, Justification for Risk-Informed Modifications to Selected Technical Specifications for
Conditions Leading to Exigent Plant Shutdown,
Revision 2, August 2010 3. American Society of Mechanical Engineers, Boiler and Pressure Vessel Code,Section XI, Rules for In-Service Inspection of Nuclear Power Plant Components
IRS B 3.6.8 B 3.6 CONTAINMENT SYSTEMS
B 3.6.8 Iodine Removal System (IRS)
BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.8-1 Revision 41 BACKGROUND The IRS is provided per Reference 1, Appendix 1C, Criteria 62, 63, and 64, to reduce the concentration of
fission products released to the containment atmosphere
following a postulated accident. The IRS would function together with the Containment Spray and Cooling Systems following a DBA to reduce the potential release of
radioactive material, principally iodine, from the
Containment Structure to the environment.
The IRS consists of three 50% capacity separate, independent (except for power), and redundant trains. Each train
includes a moisture separator, a high efficiency particulate
air filter, an activated charcoal adsorber section for
removal of radioiodines, a fan, and instrumentation. The
moisture separators function to reduce the moisture content
of the air stream. The system initiates filtered
recirculation of the containment atmosphere following
receipt of a SIAS. The system design is described in
Reference 1, Section 6.7.
The moisture separator is included for moisture (free water) removal from the gas stream. The moisture separator is
important to the effectiveness of the charcoal adsorbers.
Three IRS trains are provided to meet the requirement for separation, independence (except for power), and redundancy.
Two trains of the IRS are powered by separate ESF buses.
The third IRS train is a swing train that can be aligned to take power from either ESFs bus.
APPLICABLE The DBAs that result in a release of radioactive iodine SAFETY ANALYSES within the Containment Structure are a LOCA, a main SLB, or a CEA ejection accident. In the analysis for each of these
accidents, it is assumed that adequate containment leak
tightness exists at event initiation to limit potential
leakage to the environment. Additionally, for the LOCA and CEA ejection event, it is assumed that the amount of radioactive iodine release is limited by reducing the iodine
concentration in the containment atmosphere.
IRS B 3.6.8 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.8-2 Revision 41 The IRS design basis is established by the consequences of the limiting DBA, which is a LOCA based Maximum Hypothetical Accident (Reference 1, Section 14.24). The accident analysis (Reference 1, Section 14.24) assumes that one iodine removal unit starts within 63 seconds and a second iodine removal unit is assumed to be manually started within 20 minutes. For a CEA ejection event, two iodine removal units are assumed to be manually started within 20 minutes.
The accident analysis accounts for the reduction in airborne
radioactive iodine provided by the remaining two trains of
this filtration system.
The IRS satisfies 10 CFR 50.36(c)(2)(ii), Criterion 3.
LCO Three separate, independent (except for power), and redundant trains of the IRS are required to ensure that at
least two are available, assuming a single failure coincident with a loss of offsite power.
APPLICABILITY In MODEs 1, 2, 3, and 4, iodine is a fission product that can be released from the fuel to the reactor coolant as a
result of a DBA. The DBAs that can cause a failure of the
fuel cladding are a LOCA, main SLB, and CEA ejection
accident. Because these accidents are considered credible
accidents in MODEs 1, 2, 3, and 4, the IRS must be operable in these MODEs to ensure the reduction in iodine concentration assumed in the accident analysis.
In MODEs 5 and 6, the probability and consequences of a LOCA are low due to the pressure and temperature limitations of
these MODEs. The IRS is not required in these MODEs to remove iodine from the containment atmosphere.
ACTIONS A.1 With one IRS train inoperable, the inoperable train must be restored to OPERABLE status within seven days. The
components in this degraded condition are capable of
providing 100% of the iodine removal needs after a DBA. The
seven day Completion Time is based on consideration of such
factors as: a. The availability of the OPERABLE redundant IRS train; IRS B 3.6.8 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.8-3 Revision 52 b. The fact that, even with no IRS train in operation, almost the same amount of iodine would be removed from
the containment atmosphere through absorption by the
Containment Spray System; and c. The fact that the Completion Time is adequate to make most repairs.
B.1 If two IRS trains are inoperable, at least one IRS train must be returned to OPERABLE status within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The Condition is modified by a Note stating it is not applicable if the second IRS train is intentionally declared inoperable. The Condition does not apply to voluntary removal of redundant systems or components from service.
The Condition is only applicable if one train is inoperable for any reason and the second train is discovered to be inoperable, or if both trains are discovered to be inoperable at the same time. In addition, at least one train of containment spray must be verified to be OPERABLE within one hour. In the event of an accident, containment spray reduces the potential radioactive release from the containment, which reduces the consequences of the inoperable IRS trains. The Completion Time is based on Reference 2 which demonstrated that the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> Completion Time is acceptable based on the infrequent use of the Required Actions and the small incremental effect on plant risk.
C.1 and C.2 If the IRS train(s) cannot be restored to OPERABLE status within the required Completion Time, the plant must be
brought to a MODE in which the LCO does not apply. To
achieve this status, the plant 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 plant conditions from full
power conditions in an orderly manner and without challenging plant systems.
IRS B 3.6.8 BASES CALVERT CLIFFS - UNITS 1 & 2 B 3.6.8-4 Revision 55 SURVEILLANCE SR 3.6.8.1 REQUIREMENTS Initiating each IRS train from the Control Room and operating it for 15 minutes ensures that all trains are OPERABLE and that all associated controls are functioning
properly. It also ensures that motor failure can be detected for corrective action. The Surveillance Frequency is controlled under the Surveillance Frequency Control Program. SR 3.6.8.2 This SR verifies that the required IRS filter testing is performed in accordance with the Ventilation Filter Testing
Program. The IRS filter tests are in accordance with
portions of Reference 3. The Ventilation Filter Testing
Program includes testing high efficiency particulate air
filter performance, charcoal adsorber efficiency, minimum
system flow rate, and the physical properties of the
activated charcoal (general use and following specific
operations). Specific test frequencies and additional
information are discussed in detail in the Ventilation
Filter Testing Program.
SR 3.6.8.3 The automatic startup test verifies that both trains of equipment start upon receipt of an actual or simulated test
signal (Engineered Safety Feature Actuation System). The Surveillance Frequency is controlled under the Surveillance Frequency Control Program.
REFERENCES 1. UFSAR 2. WCAP-16125-NP-A, Justification for Risk-Informed Modifications to Selected Technical Specifications for
Conditions Leading to Exigent Plant Shutdown,
Revision 2, August 2010 3. Regulatory Guide 1.52, Revision 2, "Design, Testing, and Maintenance Criteria for Postaccident Engineered-
Safety-Feature Atmosphere Cleanup System Air Filtration
and Adsorption Units of Light-Water-Cooled Nuclear Power Plants," March 1978