L-2023-180, Submittal of Changes to the Technical Specification Bases
| ML23348A166 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 12/13/2023 |
| From: | Strand D NextEra Energy Seabrook |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| L-2023-180 | |
| Download: ML23348A166 (1) | |
Text
December 13, 2023 United States Nuclear Regulatory Commission Attn.: Document Control Desk Washington, DC 20555-0001 Seabrook Station NEXTera ENERGY
SEABROOK 10 CFR 50.71(e)
Docket No. 50-443 L-2023-180 Submittal of Changes to the Seabrook Station Technical Specification Bases NextEra Energy Seabrook, LLC submits the enclosed changes to the Seabrook Station Technical Specification Bases. The changes were made in accordance with Technical Specification 6.7.6.j.,
"Technical Specification (TS) Bases Control Program." Please update the Technical Specification Bases as follows:
Remove Insert B 3/4 3-1 BC 14-05 BC 23-01 B 3/4 3-lA BC 14-07 BC 23-01 B 3/4 3-lB BC 23-01 B 3/4 8-20 BC 21-01 BC 19-01 Should you have any questions regarding the enclosure, please contact Mr. Kenneth Mack, Fleet Licensing Manager, at 561-904-3635.
Sincerely,
<t-S:?v1 Dianne Strand General Manager Regulatory Affairs Enclosed: Incorporated changes to TS Bases cc:
NRC Region I Administrator NRC Project Manager NRC Senior Resident Inspector NextEra Energy Seabrook, LLC PO Box 300, Seabrook, NH 03874
Enclosure to L-2023-180 Incorporated Changes to TS Bases (Pages 1 of 4)
3/4.3 INSTRUMENTATION BASES 3/4.3.1 and 3/4.3.2 REACTOR TRIP SYSTEM and ENGINEERED SAFETY FEATURES ACTUATION SYSTEM INSTRUMENTATION The OPERABILITY of the Reactor Trip System and the Engineered Safety Features Actuation System instrumentation and interlocks ensures that: (1) the associated ACTION and/or Reactor trip will be initiated when the parameter monitored by each channel or combination thereof reaches its Setpoint (2) the specified coincidence logic is maintained, (3) sufficient redundancy is maintained to permit a channel to be out-of-service for testing or maintenance, and (4) sufficient system functional capability is available from diverse parameters.
The OPERABILITY of these systems is required to provide the overall reliability, redundancy, and diversity assumed available in the facility design for the protection and mitigation of accident and transient conditions. The integrated operation of each of these systems is consistent with the assumptions used in the safety analyses. The Surveillance Requirements specified for these systems ensure that the overall system functional capability is maintained comparable to the original design standards. The periodic surveillance tests performed in accordance with the Surveillance Frequency Control Program are sufficient to demonstrate this capability.
Table 3.3-1 contains the action statements for inoperable Reactor Trip System Instrumentation. Actions 4 and 5, associated with the source range neutron flux instruments, each include a requirement to suspend operations involving positive reactivity changes. When complying with this action, operations that individually add limited, positive reactivity are acceptable when, combined with other actions that add negative reactivity, the overall net reactivity addition is zero or negative. For example, a positive reactivity addition caused by temperature fluctuations from inventory addition or temperature control fluctuations is acceptable if it is combined with a negative reactivity addition such that the overall, net reactivity addition is zero or negative.
Implementation of WCAP-14333 extended the bypass test time to 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and action Completion Time to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> for the analog inputs into the Reactor Trip and ESFAS actuation systems. In addition WCAP-15376 extended the bypass time to 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> and the Completion Time to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> for actions related to Reactor Trip breakers, Reactor Trip logic, and ESFAS Actuation logic.
For analog channel surveillance testing, the 12-hour bypass time is separate from the action Completion Time of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. The Completion Time of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> begins either when the 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> of bypass time ends, or when the channel is discovered to be INOPERABLE.
SEABROOK - UNIT 1 B 3/4 3-1 Amendment No. 36, 60, BC 04 07, 14 05, 23-01
3/4.3 INSTRUMENTATION BASES 3/4.3.1 and 3/4.3.2 REACTOR TRIP SYSTEM and ENGINEERED SAFETY FEATURES ACTUATION SYSTEM INSTRUMENTATION (Continued)
For this bases section, examples of when the channel is discovered to be INOPERABLE during surveillance testing are:
A)
The channel is found out of tolerance
- 8)
The channel is found to need adjustment Westinghouse provided clarification for implementing these new time limits in OG-12-448 IL TR-PL-12-84. The following examples are provided to aid Control Room Staff in applying the revised timelines:
A)
If a pressurizer pressure channel fails during normal operation, the 72-hour Completion Time to place the affected channel in TRIP begins at the time of failure. Prior to expiration of those 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, the channel may be bypassed to support repair.
- 8)
If an ACOT is performed on the pressurizer pressure channel, the affected channel may be placed in BYPASS for up to 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. If, 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> into the test, it is discovered that the channel is INOPERABLE, then the 72-hour Completion Time clock starts at the point of discovery. The total time allowed for the channel to be in BYPASS is 78 hours9.027778e-4 days <br />0.0217 hours <br />1.289683e-4 weeks <br />2.9679e-5 months <br />; which is the 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> between the start of the test and the discovery of the INOPERABLE condition, plus 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> for the Completion Time of the action. At the 78-hour mark, the channel must be placed in TRIP.
C)
If an ACOT is performed on the pressurizer pressure channel, and the 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> bypass time limit is reached without determining the channel is INOPERABLE or OPERABLE (for example, test equipment or work group coordination problems prevent timely completion of the surveillance), then the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> action Completion Time begins. In this example, the total time the channel may be BYPASSED before being placed in the TRIP condition is 84 hours9.722222e-4 days <br />0.0233 hours <br />1.388889e-4 weeks <br />3.1962e-5 months <br />; the 12-hour bypass test time plus the 72-hour Completion Time.
The same philosophy applies to Reactor Trip Breakers, Automatic Trip, Interlock and ESFAS Logic. The following examples are provided to aid Control Room Staff in applying the revised timelines:
A)
If a Logic Train (e.g. channel) fails during normal operation, the 24-hour Completion Time per the associated Action begins at the time of failure. Prior to expiration of those 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, the channel may be bypassed to support repair.
SEABROOK - UNIT 1 B 3/4 3-1a BC 04 04, 04 07, 23-01
3/4.3 INSTRUMENTATION BASES 3/4.3.1 and 3/4.3.2 REACTOR TRIP SYSTEM and ENGINEERED SAFETY FEATURES ACTUATION SYSTEM INSTRUMENTATION (Continued)
B)
A Logic Train may be bypassed for surveillance testing for up to 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />. If 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> into the test, it is discovered that the channel is INOPERABLE, then the 24-hour Completion Time clock starts at the point of discovery. The total time allowed for the channel to be in BYPASS is 26 hours3.009259e-4 days <br />0.00722 hours <br />4.298942e-5 weeks <br />9.893e-6 months <br />; which is the 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> between the start of the test and the discovery of the INOPERABLE condition, plus 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> for the Completion Time of the action. At the 26-hour mark, the associated Action(s) must be taken.
The Engineered Safety Features Actuation System Instrumentation Trip Setpoints specified in Table 3.3-4 are the nominal values at which the bistables are set for each functional unit. A Setpoint is considered to be adjusted consistent with the nominal value when the "as measured" setpoint is within the band allowed for rack calibration accuracy and bistable setting accuracy. This setpoint methodology may result in the "as measured" trip setpoint exceeding the trip setpoint listed in the Technical Specifications. For example, a bistable with a trip setpoint of :s; 109% has a span of 120%, a rack calibration accuracy of
+/- 0.50%, and a bistable setting accuracy of+/- 0.25%. The bistable is considered to be adjusted to the trip setpoint, consistent with the Technical Specifications, as long as the "as measured" value for the bistable is :s; 109% + [(0.5 + 0.25) (120%) I 100)], or :s; 109.9%.
To accommodate the instrument drift assumed to occur between operational tests and the accuracy to which Setpoints can be measured and calibrated, Allowable Values for the Setpoints have been specified in Table 3.3-4. Operation with Setpoints less conservative than the Trip Setpoint but within the Allowable Value is acceptable since an allowance has been made in the safety analysis to accommodate this error. An optional provision has been included for determining the OPERABILITY of a channel when its Trip Setpoint is found to exceed the Allowable Value. The methodology of this option utilizes the "as measured" deviation from the specified calibration point for rack and sensor components in conjunction with a statistical combination of the other SEABROOK - UNIT 1 B 3/4 3-1b BC 23-01
ELECTRICAL POWER SYSTEMS BASES 3/4.8.3 ONSITE POWER DISTRIBUTION (continued) emergency DG supplies power to the 4.16 kV emergency buses. Control power for the 4.16 kV breakers is supplied from the Class 1 E batteries.
Although not explicitly contained in TS 3.8.3.1 and 3.8.3.2, the MCCs that support the design function of the on-site AC power system must be energized to permit the functioning of structures, systems, and components important to safety under all normal and accident conditions. The AC distribution system ensures the safety functions of the Reactor Coolant Makeup, Residual Heat Removal, Emergency Core Cooling, Containment Heat Removal, Containment Atmosphere Cleanup, and the Cooling Water Systems can be accomplished. The accident analyses assume that the ESF systems are operable, which includes the availability of necessary power. Consequently, the MCCS that support these functions are required to be energized to maintain operability of the associated ESF systems and components.
No bus ties exist between redundant buses; however, manual bus tie breakers provide the capability to interconnect load center buses within a single train. Bus ties may be used when a unit substation transformer is out of service for maintenance or repair. Bus ties are provided only for operational flexibility. The unit substations are not designed to supply the total load of both buses when bus ties are used. When a bus tie breaker is used, loading on each unit substation will be administratively controlled to be within the rating of the unit substation transformer.
The 120V Vital Instrumentation and Control Power System consists of the uninterruptible power supply (UPS) units and the 120-volt instrument panels arranged in two trains. The four vital UPS units that provide power to the four NSSS instrument channels (Channels I, II, Ill and IV) are powered from either the 480V system or the 125V DC system depending on the available 480V bus voltage. Two vital UPS units that provide redundant power supplies to the balance-of-plant train A and train B vital instrument panels are normally powered from the 480V system and can also convert 125V DC power from the station batteries to 120V AC power. These UPS units feed six electrically independent 120-volt AC vital instrument panels which serve as instrument and control power supplies.
The DC electrical power distribution system for each train consists of two 125-volt DC buses.
APPLICABLE SAFETY ANALYSES The initial conditions of Design Basis Accident (OBA) and transient SAFETY analyses in the UFSAR assume Engineered Safety Features (ESF) systems are OPERABLE. The AC, DC, and DC vital bus electrical power distribution systems are designed to provide sufficient capacity, capability, redundancy, and reliability to ensure the availability of necessary power to ESF systems so that the fuel, Reactor Coolant System, and containment design limits are not exceeded.
The OPERABILITY of the AC, DC, and AC vital bus electrical power distribution systems in MODES 1 through 4 is consistent with the initial assumptions of the accident analyses and is based upon meeting the design basis of the unit. This includes maintaining power distribution systems OPERABLE during accident conditions in the event of:
SEABROOK-UNIT 1 B 3/4 8-20 BC 04 15, 14 02, 17 02, 48-W, 21 01, 19-01