ET 22-0005, Response to Request for Additional Information Regarding License Amendment Request - Diesel Generator Completion Time Extension for Technical Specification 3.8.1, AC Sources - Operating
| ML22103A123 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 04/13/2022 |
| From: | Boyce M Wolf Creek |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| ET 22-0005 | |
| Download: ML22103A123 (51) | |
Text
P.O. Box 411 l Burlington, KS 66839 l 620-364-8831 Michael T. Boyce Vice President Engineering April 13, 2022 ET 22-0005 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555
References:
- 1) Letter ET 21-0004 dated September 29, 2021, from S. L. Smith, WCNOC, to USNRC, License Amendment Request - Diesel Generator Completion Time Extension for Technical Specification 3.8.1, AC Sources - Operating
- 2) Electronic mail dated February 23, 2022, from S. A. Lee, USNRC, to J. Turner, WCNOC, Request for additional information - Wolf Creek request to revise diesel generator completion time (EPID: L-2021-LLA-0173)
Subject:
Docket No. 50-482: Response to Request for Additional Information Regarding License Amendment Request - Diesel Generator Completion Time Extension for Technical Specification 3.8.1, AC Sources - Operating Commissioners and Staff:
Reference 1 provided the Wolf Creek Nuclear Operating Corporation (WCNOC) application for an amendment to the technical specifications (TS) for the Wolf Creek Generating Station (WCGS). The proposed amendment would modify WCGS TS 3.8.1, AC Sources - Operating, by removing requirements associated with the Sharpe Station gensets and extend the Completion Time for one inoperable diesel generator (DG) from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 14 days based on the availability of a supplemental power source (i.e., Station Blackout DG System). Reference 2 provided a request for additional information (RAI) related to the license amendment request.
Attachment I provides WCNOCs response to the RAI. Attachment II contains proposed markups of WCGS TS 3.8.1 which supersede the TS markups provided in Reference 1. Attachment III contains proposed markups of the WCGS TS 3.8.1 Bases (for information only) which supersede the TS Bases markups provided in Reference 1.
ET 22-0005 Page 2 of 3 The information provided in this submittal does not expand the scope of the application and does not impact the significance hazards consideration determination presented in Reference 1. In accordance with 10 CFR 50.91, Notice for public comment; State consultation, Section (b)(1), a copy of this amendment application is being provided to the designated Kansas State official.
The letter contains no commitments. If you have any questions concerning this matter, please contact me at (620) 364-8831 x8687, or Ron Benham at (620) 364-4204.
Sincerely, Michael T. Boyce MTB/rlt Attachment I:
Response to Request for Additional Information Regarding License Amendment Request - Diesel Generator Completion Time Extension for Technical Specification 3.8.1, AC Sources - Operating Attachment II:
Revised WCGS Technical Specification 3.8.1 Pages (Markup)
Attachment III: Revised WCGS Technical Specification 3.8.1 Bases Pages (Markup) (for information only) cc:
S. S. Lee (NRC), w/a S. A. Morris, (NRC), w/a K. S. Steves (KDHE), w/a G. E. Werner (NRC), w/a Senior Resident Inspector (NRC), w/a
Attachment I to ET 22-0005 Page 1 of 23 Response to Request for Additional Information Regarding License Amendment Request
- Diesel Generator Completion Time Extension for Technical Specification 3.8.1, AC Sources - Operating Reference 1 provided the Wolf Creek Nuclear Operating Corporation (WCNOC) application for an amendment to the technical specifications (TS) for the Wolf Creek Generating Station (WCGS). The proposed amendment would modify WCGS TS 3.8.1, AC Sources - Operating, by removing requirements associated with the Sharpe Station gensets and extend the Completion Time for one inoperable diesel generator (DG) from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 14 days based on the availability of a supplemental power source. At WCGS, the supplemental power source being credited is the Station Blackout (SBO) DG System. Reference 2 provided a request for additional information (RAI) related to the license amendment request. The NRC request is provided in italics.
RAI EEEB-1 Section 2.3.1 of Attachment I to the LAR describes the proposed TS changes to Conditions A, B, C, and H of TS 3.8.1.
As stated in Section 2.3.1.2 of Attachment I to the LAR, the licensee proposed to add a new Required Action B.2 to verify the availability of the required SBO DGs:
CONDITION REQUIRED ACTION COMPLETION TIME B. One DG inoperable.
AND B.2 Verify the required Station Blackout (SBO)
DGs are available.
1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> AND Once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> thereafter As stated in Section 2.3.1.3 of Attachment I to the LAR, the licensee proposed to revise Condition C to reflect the unavailability of the required SBO DG(s) when a DG is inoperable.
Attachment I to ET 22-0005 Page 2 of 23 As stated in Section 2.3.1.3 of Attachment I to the LAR, the licensee proposed to revise Condition H to reflect the changes to Condition B. Attachment IV to the LAR shows the licensees proposed revision to Condition H:
H. Required Action and associated Completion Time of Condition A, C, D, E, F, or G not met.
OR Required Actions B.1, B.3, B.4.1, B.4.2, and B.5 and associated Completion Time not met.
H.1 Be in MODE 3.
AND H.2 Be in MODE 5.
6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> 36 hours Section 2.3.1.2 of Attachment I to the LAR states:
Unavailability of the required SBO DGs does not, by itself, result in the LCO not being met.
However, BTP 8-8 states, in part, that the plant should start shutting down the unit within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> if the supplemental source becomes unavailable any time during the extended AOT.
The licensee used OR to connect the two CTs for Condition C, meaning these CTs apply alternatively. The first alternate CT states 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> from discovery of unavailability of required SBO DGs. The NRC staff understands that if the SBO DGs becomes unavailable during the extended CT, the DG could remain inoperable for an additional 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> instead CONDITION REQUIRED ACTION COMPLETION TIME C. Required Action B.2 and C.1 Restore DG to OPERABLE 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> from associated Completion Time not status or restore required SBO discovery of met.
to available status.
unavailability of required SBO DGs OR 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> from discovery of Condition B entry
= [] 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> concurrent with unavailability of required SBO DGs
Attachment I to ET 22-0005 Page 3 of 23 of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> from discovery of unavailability of SBO DGs before the plant would enter Condition H to start shutting down when the DG cannot be restored to operable status. This does not appear consistent with the recommendations of BTP 8-8.
The licensee proposed an alternate Required Action C.1 to restore required SBO DGs to available status within the alternate CTs of Condition C. The NRC staff understands that the plant would continue operating (1) with an inoperable DG and unavailable SBO DGs for more than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> up to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> after discovery of SBO DGs unavailability during the extended CT instead of shutting down after 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, as recommended by BTP 8-8, and (2) with an inoperable DG for a period of up to 14 days including a 72-hour period of SBO DGs unavailability after restoring the SBO DGs to available status. This also does not appear consistent with the recommendations of BTP 8-8.
Please address the following:
- a. Provide justifications for (1) the proposed first CT (72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> from discovery of unavailability of required SBO DGs) of Condition C and (2) the proposed alternate Required Action C.1 to restore required SBO DGs to available status, each of which would allow the plant continued operation with an inoperable DG for more than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> up to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> after discovery of SBO DGs unavailability during the extended CT. Alternatively, provide TS CT that would allow 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of continued operation from discovery of SBO DGs unavailability, consistent with BTP 8-8.
- b. The proposed CT for Required Action C.1 does not appear to require appropriate remedial measures within an appropriate time when the LCO is not met. In addition, the proposed CT appears too long compared to the CT recommended by BTP 8-8.
Please provide a discussion of other remedial measures, taken in CTs shorter than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, that may be appropriate.
Response to RAI EEEB-1
- a. WCNOC is proposing to revise the new Condition C as follows:
CONDITION REQUIRED ACTION COMPLETION TIME C.
Required Action B.2 and associated Completion Time not met.
C.1 Restore DG to OPERABLE status.
72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> from Condition B entry OR 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> from Condition B entry 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> concurrent with unavailability of required SBO DGs
Attachment I to ET 22-0005 Page 4 of 23 OR C.2 Restore required SBO DGs to available status.
72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> from Condition B entry OR 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> from Condition B entry 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> concurrent with unavailability of required SBO DGs Attachment II contains proposed markups of WCGS TS 3.8.1 which supersede the TS markups provided in Reference 1. Attachment III contains proposed markups of the WCGS TS 3.8.1 Bases (for information only) which supersede the TS Bases markups provided in Reference 1.
In Reference 1, WCNOC had originally proposed Condition C as follows:
CONDITION REQUIRED ACTION COMPLETION TIME C.
Required Action B.2 and associated Completion Time not met.
C.1 Restore DG to OPERABLE status or restore required SBO DGs to available status.
72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> from discovery of unavailability of required SBO DGs OR 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> from discovery of Condition B entry 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> concurrent with unavailability of required SBO DGs TS Section 1.3, Completion Times, states, in part:
The Completion Time is the amount of time allowed for completing a Required Action. It is referenced to the discovery [emphasis added] of a situation (e.g., inoperable equipment or variable not within limits) that requires entering an ACTIONS Condition unless otherwise specified, providing the unit is in a MODE or specified condition stated in the Applicability of the LCO.
Attachment I to ET 22-0005 Page 5 of 23 As such, the Completion Time of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> from discovery of unavailability of required SBO DGs would start a new 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> clock at the time it was discovered that a required SBO DG was unavailable. This could allow up to 120 hours0.00139 days <br />0.0333 hours <br />1.984127e-4 weeks <br />4.566e-5 months <br /> from initial DG inoperability to restore either the DG or the required SBO DG after the discovery of an unavailable required SBO DG. A review of the Catawba Nuclear Station Safety Evaluation for Amendment Nos. 304 and 300 (Reference 3) and the McGuire Nuclear Station Safety Evaluation for Amendment Nos. 314 and 293 (Reference
- 4) determined that the NRC position is that the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> Completion Time must be met upon discovery of an unavailable required SBO DG. The new proposed changes to Condition C would require restoring the inoperable DG or unavailable required SBO DG within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> of entry into Condition B (declaring the DG inoperable) or within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of discovering the required SBO DG is unavailable if the DG had been inoperable for 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />. The 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> Completion Time takes into account the capacity and capability of the remaining AC source, a reasonable time for repairs, and low probability of a design basis accident (DBA) occurring during this period.
The use of the logical connector OR in the Completion Time allows for alternative choices, only one of which must be performed. In Reference 1, a regulatory commitment was made that the extended Completion Time (14 days) for an inoperable DG will be used no more than once in an 18-month period on a per DG basis to perform DG planned maintenance. Additionally, Section 3.7 of Attachment I of Reference 1, identified that WCNOC has developed the practice of scheduling work for only 50 percent of the Completion Time for planned maintenance. Provided below are some example applications of the new proposed Condition C/Required Actions/Completion Times.
- 1. A DG is declared inoperable for voluntary planned maintenance (not using the extended Completion Time allowance) and it is scheduled for 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> or less. Condition B is entered and the Required Actions of Condition B taken. While performing Required Action B.2, a required SBO DG is determined to be unavailable at 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> after initial entry into Condition B. Condition C is entered and the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> Completion Time is applied from the initial entry into Condition B.
- 2. An unplanned DG outage occurs when the B DG is declared inoperable when it is identified that the B DG room supply fan tripped and it was identified that the motor needed to be replaced. It was determined that it would take approximately 90 hours0.00104 days <br />0.025 hours <br />1.488095e-4 weeks <br />3.4245e-5 months <br /> to replace the fan motor and restore the B DG to OPERABLE status. While performing Required Action B.2, a required SBO DG is determined to be unavailable at 58 hours6.712963e-4 days <br />0.0161 hours <br />9.589947e-5 weeks <br />2.2069e-5 months <br /> after initial entry into Condition B. Condition C is entered and the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> Completion Time is applicable for restoring the B DG to OPERABLE status or returning the required SBO DG to available status.
From the above, use of the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> Completion Time is utilized for those cases when the extended Completion Time is applicable consistent with the guidance in Branch Technical Position (BTP) 8.8, Onsite (Emergency Diesel Generators) and Offsite Power Sources Allowed Outage Time Extensions.
The RAI indicates that proposed Required Action C.1 would allow the plant to continue operating with an inoperable DG for a period of up to 14 days including a 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> period of required SBO DG unavailability after restoring the required SBO DG(s) to available status. TS Section 1.3, Completion Times, states, in part:
Attachment I to ET 22-0005 Page 6 of 23 Required Actions must be completed prior to the expiration of the specified Completion Time.
An ACTIONS Condition remains in effect and the Required Actions apply until the Condition no longer exists or the unit is not within the LCO Applicability.
If situations are discovered that require entry into more than one Condition at a time within a single LCO (multiple Conditions), the Required Actions for each Condition must be performed within the associated Completion Time.
These TS requirements in Section 1.3 specify that upon entry into Condition B for an inoperable DG, the clock for the 14 day Completion Time is started and the DG must be restored to OPERABLE status by the end of the 14 days. If a required SBO DG was determined to be unavailable at 13 days and 20 hours2.314815e-4 days <br />0.00556 hours <br />3.306878e-5 weeks <br />7.61e-6 months <br /> after the entry into Condition B for an inoperable DG, Condition C would be entered and Required Action C.2 allows 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to restore the DG to OPERABLE status. However, proposed Required Action B.5 would still have to be met and the DG restored to OPERABLE status at the end of the 14 days. If the DG were not restored to OPERABLE status within the 14 day Completion Time, then Condition H would be entered and a plant shutdown initiated.
- b. The response to this item is encompassed in the response to item a. of the RAI.
RAI EEEB-2 Section 3.4.1 of Attachment I to the LAR states:
The SBO DG System includes three non-safety related Kohler 3250 kW DGs and one Power Equipment Center (PEC).
Section 3.4.2 of Attachment I to the LAR states:
Three DGs sufficiently power all LOOP [loss of offsite power] loads. An engineering evaluation was performed utilizing the Electrical Transient Analysis Program (ETAP) to perform load flow, short circuit, and motor starting analyses for LOOP scenarios. Calculation XX-E-022 and the engineering evaluation determined that two SBO DGs can successfully start the minimum required safe shutdown loads with sufficient starting voltages provided the loads are manually started with at least 30 seconds provided between starts.
BTP 8-8 recommends that the supplemental power source capable of supplying the LOOP loads to bring the unit to a cold shutdown be provided as a backup to a single inoperable EDG in case of a LOOP event concurrent with a failure of the remaining DG during the extended AOT.
Provide a summary of the evaluation performed to determine that two SBO DGs can successfully start the minimum required safe shutdown loads with sufficient starting voltages to bring the unit to cold shutdown during an SBO, consistent with the recommendation of BTP 8-8.
Response to RAI EEEB-2 Section 3.4.2 of Reference 1 identified that Calculation XX-E-022, SBO Diesel Generators - AC System Analysis, and an engineering evaluation was performed utilizing the Electrical Transient Analysis Program (ETAP) to perform load flow, short circuit, and motor starting analyses for loss
Attachment I to ET 22-0005 Page 7 of 23 of offsite power (LOOP) scenarios. Calculation XX-E-022 has been revised to incorporate information from the engineering evaluation and other Calculation Change Notices and includes an update to Version 18.1.1 N of the ETAP software.
Calculation XX-E-022 provides the analysis which demonstrates the capability of two of the three installed SBO DGs to successfully start the minimum required safe shutdown LOOP loads (5581 kW) with sufficient starting voltages. In addition, other cases are performed within this calculation to identify the full capabilities of the SBO DGs.
Analytical Results The ETAP configurations (scenarios) were run and analyzed to verify that buses and loads met the acceptance criteria during load flow, short circuit, and motor starting conditions.
Load Flow
- 1. Load flow cases were analyzed to identify if the cables could sufficiently supply LOOP loads without exceeding rated ampacity.
- a. Load flow reports show the following loading on the cables feeding the NB01 and NB02 buses.
PB05 to NB01 PB05 to NB02 All LOOP Loads 869.9 A @ 4078 V 888.8 A @ 4078 V Reduced LOOP Loading 771.7 A @ 4078 V 790.5 A @ 4078 V
- b. The loading for All LOOP loads is slightly above the Total Load on Diesel Generator from Drawing E-11005 (Figure 1). This difference is due to the fact that ETAP will only accept an integer as a loading percentage, and all medium voltage motors were modeled with a load slightly higher than in Drawing E-11005.
- c. Drawing E-11005 adjusts the total loading for over-frequency conditions as well as cable losses. The total adjusted loading calculated by multiplying the cable loading by the ratio of total load (kW) on the SBO DG (frequency adjusted, with cable losses) to the total unadjusted load (kW) on the SBO DG from Drawing E-11005 is as follows:
PB05 to NB01 PB05 to NB01 Maximum Ampacity PB05 to NB02 PB05 to NB02 Maximum Ampacity All LOOP Loads 899.5 A @ 4078 V (917.6 A @ 4160 V)*
921.4A @ 4160V 919.0 A @ 4078 V (937.5 A @ 4160 V)*
914.7 A @ 4160V All LOOP Loads 899.5 A @ 4078 V (881.7 A @ 4160 V)**
921.4A @ 4160V 919.0 A @ 4078 V (900.9 A @ 4160 V)**
914.7 A @ 4160V
- Conservatively assumes all loads are static.
- Assumes all loads are constant kVA.
Attachment I to ET 22-0005 Page 8 of 23
- d. Per the Project Cable Ampacity Calculation, the maximum recommended capacity for the cables from PB05 to NB01 is 921.4 Amps and from PB05 to NB02 is 914.7 Amps. Based on the loading adjustment information from Drawing E-11005 and the relationship between the ETAP loading and non-adjusted loading from Drawing E-11005, it is determined that the resultant loading adjusted for frequency and cable losses may exceed the maximum recommended capacity of the cables for LOOP loading. Note that in the first table above, all loads are assumed to be static which is conservative while in the second table above all loads are assumed to be constant kVA loads. While assuming all loads to be static is conservative, it is still possible that the maximum ampacity is exceeded with all LOOP loads on bus NB02. Procedure SYS KU-122, Energizing NB02 from Station Blackout Diesel Generators, includes precautions/limitations for cable overload. The cable overload limits apply to the cable between breaker PB00508 and NB0114 or breaker PB00509 and NB0214. A cable overload alarm will actuate Main Control Board alarm 00-020F, SBO DG SYSTEM TROUBLE, at 850 Amps. SBO breaker PB00508/PB00509 will trip open at 936 Amps. Alarm response procedure 00-020F, SBO DG System Trouble, directs the operator to consider reducing load to below 850 Amps.
- e. Caution should be used when approaching the maximum ampacity. Suggested loading and operator actions to minimize the loading on the feeder cables are provided in plant procedures. The alarms for these cables are set at 850A but the actual loading is expected to reach 863A for LOOP loading. SBO DG KU01B is operating slightly above its rating while SBO DG KU01A does not exceed its rating. This is due to the impedance difference in the cables from the generators to bus PB05 which results from the difference in cable lengths. Per the Kohler Factory Tests Reports, the maximum operating power is 3318 kW. SBO DG KU01B does not exceed the maximum operating power of 3318 kW in any case.
- 2. A load flow case was analyzed to ensure 480V load centers/motor control centers (LC/MCC) voltages did not exceed or fall below the acceptance criteria in steady state conditions immediately following a loss of offsite power to Bus NB02 with loss of coolant accident (LOCA) conditions and after all of the required loads have been placed back in service. All LC and MCC voltages remained within the acceptance criteria.
Short Circuit Short Circuit cases were analyzed to ensure the SBO DGs could be tested while connected to the utility source. Short circuit reports show that the NB01 and NB02 bus can be fully loaded with three SBO DGs connected to one bus and in operation without reaching the rated fault current value of any equipment. This is the bounding case. A summary of Class 1E buses included is shown in Figure 2.
Motor Starting
- 1. Motor starting cases were analyzed to ensure the bus and motor voltages remained within the acceptance criteria when sequencing loads.
- a. All bus and motor voltages remained within the acceptance criteria. See Tables 1, 2 and 3 for a summary of motor starting voltages.
Attachment I to ET 22-0005 Page 9 of 23 Table 1: WCGS Safe Shutdown Loads, Time & Sequence, and Starting Voltage Results Note 1: Hydrogen Mixing Fans are started with the dead bus loads at T = 0.5 seconds.
Note 2: ESW Pump Strainer (DFEF02B) is started 8 seconds after the ESW pump (DPEF01B) to allow for sufficient starting voltage. The acceleration time of the ESW pump is 4 seconds at 100% voltage. To account for lower than 100% voltage, a staggered time of 8 seconds was selected.
Additional Comments:
- 1. Dead bus loads are started at T = 0.5 seconds in the ETAP model. All subsequent sequences are staggered 30 seconds apart. (Sequence 1 loads are started at T = 30.5 seconds, Sequence 2 at T = 60.5 seconds, etc.)
- 2. Battery Chargers NK22, NK24, NK26 loading are updated in the ETAP model to match drawing E-11005.
Because they are represented as lumped loads and cannot be started in the ETAP study case, they are at steady state throughout the entire study case.
- 3. Inverters NN12 and NN14 are converted from single phase motors to three phase motors in the ETAP model and are started with the dead bus loads at T = 0.5 seconds.
- 4. Hydrogen mixing fans (DCGN03B and DCGN03D) are started with the dead bus loads at T = 0.5 seconds.
Because they have sufficient voltage to start, they are not started again in Sequence 7, meaning that Sequence 8 loads are started 30 seconds after Sequence 6.
- 5. ESW Pump House Supply Fan (DCGD01B) is started at T = 30.5 seconds in Sequence 1 (it is not started as a dead bus load).
Time Start Load Name ETAP Load ID Voltage Criteria Starting Voltage Margin Sequence Number 0.5 Hydrogen Mixing Fan DCGN03B FAST 80%
87.63%
7.63%
0 (Dead Bus) 0.5 Hydrogen Mixing Fan DCGN03D FAST 80%
89.05%
9.05%
0 (Dead Bus) 30.5 Essential Service Water (ESW) Pump House Supply Fan DCGD01B 65%
75.17%
10.17%
1 30.5 ESW Traveling Water Screens DFEF01B 65%
75.08%
10.08%
1 30.5 ESW Pump DPEF01B 75%
75.52%
0.52%
1 38.5 ESW Pump Strainer DFEF02B 85%
98.04%
13.04%
1a (See Note 2) 60.5 Component Cooling Water Pump DPEG01B 75%
87.54%
12.54%
2 60.5 Component Cooling Water Pump Room Cooler DSGL11B 65%
77.19%
12.19%
2 90.5 Instrument and Service Air Compressor DCKA01B 75%
80.05%
5.05%
3 120.5 Centrifugal Charging Pump DPBG05B 70%
87.46%
17.46%
4 120.5 Centrifugal Charging Pump Room Cooler DSGL12B 65%
83.17%
18.17%
4 150.5 Containment Fan Cooler DSGN01B SLOW 65%
88.11%
23.11%
5 180.5 Containment Fan Cooler DSGN01D SLOW 65%
85.36%
20.36%
6 Note 1 Hydrogen Mixing Fan DCGN03B FAST 80%
Note 1 7
Note 1 Hydrogen Mixing Fan DCGN03D FAST 80%
Note 1 7
210.5 Auxiliary Feed Water Pump DPAL01B 75%
81.95%
6.95%
8 210.5 Auxiliary Feed Water Pump Room Cooler DSGF02B 65%
72.50%
7.50%
8 240.5 Backup Pressurizer Heaters Press Htr Grp "B"
- 1 - #10 9
270.5 Control Rod Drive Mechanism Cooling Fan DCGN01B 85%
88.23%
3.23%
10 300.5 Spent Fuel Pool Cooling Pump DPEC01B 65%
84.32%
19.32%
11 300.5 Spent Fuel Pool Pump Room Cooler DSGG04B 65%
81.69%
16.69%
11 330.5 Residual Heat Removal (RHR) Pump DPEJ01B 75%
83.78%
8.78%
12 330.5 RHR Pump Room Cooler DSGL10B 65%
78.45%
13.45%
12
Attachment I to ET 22-0005 Page 10 of 23 Table 2: Dead Bus Loads Immediately Started When Bus NB01 and NB02 Energized Dead Bus Loads started at T = 0.5s Load Description NG02A MOVs MOV Loads NG02B MOVs MOV Loads NG04C MOVs MOV Loads NG06E MOVs MOV Loads XNG02A Distribution Panel Loads XNG02B Distribution Panel Loads XNG04C Distribution Panel Loads XNG04D Distribution Panel Loads XNG06E Distribution Panel Loads DCGM01B Diesel Generator Building Supply Fans DPKJ03B EDG Lube Oil/Keep Warm Pumps DPKJ02B EDG Rocker Arm Pre-Lube Pumps NN12/NN14*
480/120V NN Inverter BCTV XQB51 Standby AC Lighting XQB60 Standby AC Lighting XQB70 Standby AC Lighting XQB85 Standby AC Lighting XQB95 Standby AC Lighting XPN08A Non-Class 1E Instrument AC Power EGD01B ESW Pump House Heaters EGD01D ESW Pump House Heaters EGD01F ESW Pump House Heaters EGD01H ESW Pump House Heaters
- Single phase motor converted to three phase for the motor starting ETAP study case.
Table 3: Battery Chargers Lumped loads assumed steady state at T = 0 (are not started in the motor starting study case)
Load Description NK026 125VDC Swing Battery Chargers NK022 125VDC Battery Chargers NK024 125VDC Battery Chargers
- 2. Motor starting cases were analyzed to ensure that the bus and motor voltages remained within the overvoltage acceptance criteria when the largest load was removed.
- a. Motor starting reports show that the removal of the largest load on the system when all other loads are run in steady state does not increase any bus or motor voltages to above 110% of rated voltage.
- b. Motor starting cases were analyzed to ensure the bus and motor voltages did not drop below the acceptance criteria while bus NB02 is powered solely by SBO DGs in various LOCA loading conditions when the ESW or Auxiliary Feedwater Pumps are started.
Attachment I to ET 22-0005 Page 11 of 23 Conclusion SBO Case - 2 SBO DGs Supplying LOOP Loads
- 1. It is concluded that two SBO DGs can successfully start the minimum required safe shutdown loads with sufficient starting voltages to bring the unit to cold shutdown during an SBO, consistent with BTP 8-8.
- 2. Voltage Drop and Recovery Time: The load sequencing indicated in Figure 3 does not cause a voltage drop which exceeds the acceptance criteria when two SBO DGs are connected to LOOP loads.
- 3. Overvoltage Recovery: When the SBO DGs are fully loaded and the largest load is removed, the motor and bus voltages remain within acceptance criteria when two SBO DGs are operating.
- 4. Frequency Drop and Recovery Time: All of the loading steps stated in Kohler Generator Sizing Summary for LOOP loading conditions do not cause a frequency drop of more than 5%, and therefore meet acceptance criteria. The largest frequency drop stated in the Kohler Generator Sizing Summary is 1.86%. Therefore, the frequency does not need to recover in order to meet acceptance criteria.
- 5. Fault Current Rating: The cases evaluated to analyze fault current contributions of the SBO DGs show that, when connected to the grid and all loads are energized, the fault current does not exceed the rated fault current at any equipment.
- 6. Loading of Cables: The Reduced LOOP loading case allows the cables to be loaded under the maximum capacity. Operating all LOOP loads requires the cables feeding the NB02 bus to be loaded beyond their maximum capacity when all loads are conservatively assumed to be static. A Main Control Board alarm and trip of the applicable breaker provides for cable protection. The limitation is acceptable. Operations by procedure SYS-KU-122, will maintain loading on the cable feeding NB02 below 850 A. Alarm response procedures provides guidance for a Cable Overload Alarm.
XX-E-022-001-CN004 Page 1 of 1 Figure 1 Attachment I to ET 22-0005 Page 12 of 23
1/2 Cycle
% Margin 1.5 to 4 Cycle
% Margin 30 Cycle (3 Phase) 1/2 Cycle
% Margin 1.5 to 4 Cycle
% Margin 30 Cycle (3 Phase) 1/2 Cycle
% Margin 1.5 to 4 Cycle
% Margin 30 Cycle (3 Phase) 1/2 Cycle
% Margin 1.5 to 4 Cycle
% Margin 30 Cycle (3 Phase) 1/2 Cycle
% Margin 1.5 to 4 Cycle
% Margin 30 Cycle (3 Phase)
NB01 4160 66 44.68 43.198 34.55 28.648 35.88 26.019 48.650 26.29 32.407 27.47 28.832 53.859 18.40 36.073 19.26 31.595 37.341 43.42 24.800 44.49 23.157 37.342 43.42 24.801 44.49 23.158 NB02 4160 66 44.68 40.569 38.53 26.630 40.40 24.960 40.569 38.53 26.630 40.40 24.961 40.569 38.53 26.630 40.40 24.961 46.395 29.70 30.475 31.79 27.821 51.824 21.48 34.226 23.40 30.631 PB05 4160 66 44.68 38.671 41.41 26.744 40.14 24.331 44.692 32.28 30.648 31.41 27.222 50.678 23.22 34.557 22.66 30.116 40.785 38.20 28.184 36.92 25.778 46.795 29.10 32.089 28.18 28.670 LC NG01 480 N/A 30 25.899 13.67 20.788 26.108 12.97 20.990 26.275 12.42 21.156 25.619 14.60 20.537 25.619 14.60 20.537 LC NG02 480 N/A 30 25.614 14.62 20.710 25.614 14.62 20.710 25.614 14.62 20.710 25.862 13.79 20.931 26.050 13.17 21.111 LC NG03 480 N/A 30 25.494 15.02 20.909 25.695 14.35 21.104 25.854 13.82 21.264 25.226 15.91 20.667 25.226 15.91 20.667 LC NG04 480 N/A 30 25.633 14.56 20.485 25.633 14.56 20.485 25.633 14.56 20.485 25.863 13.79 20.690 26.037 13.21 20.857 LC PG21 480 N/A 30 15.702 47.66 15.558 15.807 47.31 15.663 15.889 47.04 15.749 15.562 48.13 15.427 15.562 48.13 15.427 LC PG22 480 N/A 30 15.736 47.55 15.615 15.763 47.46 15.615 15.736 47.55 15.615 15.861 47.13 15.731 15.955 46.82 15.825 MCC NG01A 480 N/A 25 23.586 5.66 19.194 23.756 4.98 19.364 23.890 4.44 19.503 23.359 6.56 18.981 23.359 6.56 18.981 MCC NG01B 480 N/A 25 17.804 28.78 14.934 17.895 28.42 15.033 17.966 28.14 15.114 17.683 29.27 14.809 17.683 29.27 14.809 MCC NG02A 480 N/A 25 21.767 12.93 17.988 21.767 12.93 17.988 21.767 12.93 17.988 21.938 12.25 18.150 22.067 11.73 18.282 MCC NG02B 480 N/A 25 14.173 43.31 12.003 14.173 43.31 12.003 14.173 43.31 12.003 14.237 43.05 12.072 14.285 42.86 12.126 MCC NG03C 480 N/A 25 19.520 21.92 16.585 19.632 21.47 16.703 19.720 21.12 16.800 19.370 22.52 16.436 19.370 22.52 16.436 MCC NG03D 480 N/A 25 19.314 22.74 16.564 19.425 22.30 16.683 19.514 21.95 16.781 19.163 23.35 16.414 19.163 23.35 16.414 MCC NG04C 480 N/A 25 18.778 24.89 15.791 18.778 24.89 15.791 18.778 24.89 15.791 18.895 24.42 15.909 18.983 24.07 16.004 MCC NG04D 480 N/A 25 19.542 21.83 16.430 19.542 21.83 16.430 19.542 21.83 16.430 19.670 21.32 16.558 19.767 20.93 16.662 MCC NG05E 480 N/A 25 6.269 74.93 6.083 6.284 74.86 6.099 6.296 74.81 6.112 6.248 75.01 6.063 6.248 75.01 6.063 MCC NG06E 480 N/A 25 6.157 75.37 5.975 6.157 75.37 5.975 6.157 75.37 5.975 6.174 75.30 5.992 6.188 75.25 6.005 1/2 Cycle
% Margin 1.5 to 4 Cycle
% Margin 30 Cycle (3 Phase) 1/2 Cycle
% Margin 1.5 to 4 Cycle
% Margin 30 Cycle (3 Phase) 1/2 Cycle
% Margin 1.5 to 4 Cycle
% Margin 30 Cycle (3 Phase) 1/2 Cycle
% Margin 1.5 to 4 Cycle
% Margin 30 Cycle (3 Phase) 1/2 Cycle
% Margin 1.5 to 4 Cycle
% Margin 30 Cycle (3 Phase)
NB01 4160 66 44.68 37.342 43.42 24.801 44.49 23.158 58.764 10.96 37.551 15.96 31.595 42.265 35.96 26.277 41.19 23.158 58.246 11.75 37.432 16.22 31.595 40.919 38.00 25.783 42.29 23.158 NB02 4160 66 44.68 57.009 13.62 37.880 15.22 33.388 45.408 31.20 28.108 37.09 24.961 61.856 6.28 39.357 11.91 33.388 44.087 33.20 27.613 38.20 24.961 61.348 7.05 39.238 12.18 33.388 PB05 4160 66 44.68 52.774 20.04 35.999 19.43 31.564 54.241 17.82 35.809 19.85 30.116 56.180 14.88 37.225 16.69 31.564 54.290 17.74 35.797 19.88 30.116 56.273 14.74 37.222 16.69 31.564 LC NG01 480 N/A 30 25.619 14.60 20.537 26.387 12.04 21.156 25.833 13.89 20.537 26.380 12.07 21.156 25.782 14.06 20.537 LC NG02 480 N/A 30 26.201 12.66 21.260 25.804 13.99 20.710 26.303 12.32 21.260 25.758 14.14 20.710 26.297 12.34 21.260 LC NG03 480 N/A 30 25.226 15.91 20.667 25.961 13.46 21.264 25.431 15.23 20.667 25.955 13.48 21.264 25.383 15.39 20.667 LC NG04 480 N/A 30 26.177 12.74 20.995 25.809 13.97 20.485 26.272 12.43 20.995 25.767 14.11 20.485 26.266 12.45 20.995 LC PG21 480 N/A 30 15.562 48.13 15.427 15.945 46.85 15.749 15.670 47.77 15.427 15.941 46.86 15.749 15.644 47.85 15.427 LC PG22 480 N/A 30 16.030 46.57 15.902 15.832 47.23 15.615 16.082 46.39 15.902 15.809 47.30 15.615 16.079 46.40 15.902 MCC NG01A 480 N/A 25 23.359 6.56 18.981 23.981 4.07 19.503 23.533 5.87 18.981 23.976 4.10 19.503 23.492 6.03 18.981 MCC NG01B 480 N/A 25 17.683 29.27 14.809 18.014 27.94 15.114 17.776 28.89 14.809 18.011 27.96 15.114 17.754 28.98 14.809 MCC NG02A 480 N/A 25 22.170 11.32 18.390 21.898 12.41 17.988 22.241 11.04 18.390 21.867 12.53 17.988 22.236 11.05 18.390 MCC NG02B 480 N/A 25 14.322 42.71 12.171 14.223 43.11 12.003 14.348 42.61 12.171 14.211 43.16 12.003 14.347 42.61 12.171 MCC NG03C 480 N/A 25 19.370 22.52 16.436 19.779 20.88 16.800 19.486 22.06 16.436 19.776 20.90 16.800 19.458 22.17 16.436 MCC NG03D 480 N/A 25 19.163 23.35 16.414 19.573 21.71 16.781 19.279 22.88 16.414 19.570 21.72 16.781 19.251 22.99 16.414 MCC NG04C 480 N/A 25 19.053 23.79 16.082 18.868 24.53 15.791 19.101 23.60 16.082 18.847 24.61 15.791 19.098 23.61 16.082 MCC NG04D 480 N/A 25 19.844 20.62 16.747 19.641 21.44 16.430 19.897 20.41 16.747 19.617 21.53 16.430 19.894 20.42 16.747 MCC NG05E 480 N/A 25 6.248 75.01 6.063 6.305 74.78 6.112 6.264 74.94 6.063 6.304 74.78 6.112 6.260 74.96 6.063 MCC NG06E 480 N/A 25 6.198 75.21 6.016 6.170 75.32 5.975 6.205 75.18 6.016 6.167 75.33 5.975 6.205 75.18 6.016 1/2 Cycle
% Margin 1.5 to 4 Cycle
% Margin 30 Cycle (3 Phase) 1/2 Cycle
% Margin 1.5 to 4 Cycle
% Margin 30 Cycle (3 Phase)
NB01 4160 66 44.68 53.071 19.59 33.775 24.41 28.832 40.919 38.00 25.783 42.29 23.158 NB02 4160 66 44.68 44.087 33.20 27.613 38.20 24.961 56.195 14.86 35.594 20.34 30.631 PB05 4160 66 44.68 48.320 26.79 31.888 28.63 27.222 50.304 23.78 33.312 25.44 28.670 LC NG01 480 N/A 30 26.236 12.55 20.990 25.782 14.06 20.537 LC NG02 480 N/A 30 25.758 14.14 20.710 26.166 12.78 21.111 LC NG03 480 N/A 30 25.817 13.94 21.104 25.382 15.39 20.667 LC NG04 480 N/A 30 25.767 14.11 20.485 26.145 12.85 20.857 LC PG21 480 N/A 30 15.870 47.10 15.663 15.644 47.85 15.427 LC PG22 480 N/A 30 15.809 47.30 15.615 16.014 46.62 15.825 MCC NG01A 480 N/A 25 23.860 4.56 19.364 23.492 6.03 18.981 MCC NG01B 480 N/A 25 17.950 28.20 15.033 17.754 28.98 14.809 MCC NG02A 480 N/A 25 21.867 12.53 17.988 22.147 11.41 18.282 MCC NG02B 480 N/A 25 14.211 43.16 12.003 14.314 42.74 12.126 MCC NG03C 480 N/A 25 19.700 21.20 16.703 19.458 22.17 16.436 MCC NG03D 480 N/A 25 19.494 22.03 16.683 19.251 22.99 16.414 MCC NG04C 480 N/A 25 18.847 24.61 15.791 19.037 23.85 16.004 MCC NG04D 480 N/A 25 19.617 21.53 16.430 19.827 20.69 16.662 MCC NG05E 480 N/A 25 6.294 74.83 6.099 6.260 74.96 6.063 MCC NG06E 480 N/A 25 6.167 75.33 5.975 6.196 75.22 6.005 SC NSAFP A SC NSAFP B SC1 3DGNB1 SC1 1DGNB2 SC1 2DGNB2 SC1 3DGNB1A SC1 3DGNB2A WCNOC Bus Name Bus Voltage Mom.
Rating (1/2 Cycle) (kA)
Rated Short Circuit Current (kA)
SC1 1DGNB1 SC1 2DGNB1 WCNOC Bus Name Bus Voltage Mom.
Rating (1/2 Cycle) (kA)
Rated Short Circuit Current (kA)
SC1 3DGNB2 SC NSAFPB 2G WCNOC Bus Name Bus Voltage Mom.
Rating (1/2 Cycle) (kA)
Rated Short Circuit Current (kA)
SC NSAFPA 2G Figure 2 Attachment I to ET 22-0005 Page 13 of 23
yy E
Page1of1 Seq.
TOTALLOAD
(kW)
TOTAL
Current (p.f.=0.85)
Procedure/Step Load<Allow30secondsbetweenstarts.>
LOAD (kW)
SupportingLoad/Current LOAD (kW)
SupportingLoad/Current LOAD (kW)
SupportingLoad/Current LOAD (kW) 1 1,526.57 249.25 EMGC0,Step12c or OFNNB030,stepA28(B28)
EssentialServiceWaterPump(PEF01AorB) 1,509.16 ESWPumpHouseSupplyFan (CGD01AorB) 14.45 ESWTravelingWaterScreen (FEF01AorB) 2.96 1a 1.69 0.28 n/a ESWPumpStrainer (FEF02AorB) 1.69 Assumption:ESWPumpStrainerstartis
delayed8sec.(BasedonnoD/Pacross
strainerforthefirst8seconds) 2 2,042.63 333.52 OFNNB030,stepA29(B29)
CCWPump(PEG01A,B,C,orD)(506.93amps) 506.93 CCWPumpRoomCooler(SGL11AorB) 9.13 3
2,235.73 365.05 OFNNB030,stepA30(B30)
InstrumentAirCompressor(CKA01AorB) 193.10 4
2,629.37 429.32 OFNNB030,stepD1 CentrifugalChargingPump(PBG05AorB) 384.47 CCPRoomCoolerSGL12AorB 9.17 5
2,669.73 435.91 OFNNB030,stepA32(B32)
ContainmentFanCoolers(SGN01AorB)(SLOW) 40.36 6
2,710.09 442.50 OFNNB030,stepA32(B32)
ContainmentFanCoolers(SGN01CorD)(SLOW) 40.36 7
2,732.45 446.15 OFNNB030,stepA34(B34)
HydrogenMixingFans(SelectedspeedFast) 22.36 8
3,292.46 537.59 OFNNB030,stepA36(B36)
MDAFWPump(PAL01AorB)
<Operatordiscretion.>
551.50 MDAFWPumpRoomCooler (SGF02AorB) 8.51 9
3,984.86 650.64 OFNNB030,stepA37(B37)
PZRHeaterB/UGroupAorB 692.40 10 4,008.17 654.45 OFNNB030,stepA38(B38)
CRDMFan(CGN01DorB) 23.31 11 4,109.51 670.99 OFNNB030,stepA41(B41)
SFPCoolingPump(PEC01AorB) 98.90 SFPCoolPumpRmCooler(SGG04AorB) 2.44 12 4,498.60 734.52 EMGES04,step32 RHRPump(PEJ01AorB) 381.60 RHRPumpRoomCooler(SGL10AorB) 7.49 Figure 3 Attachment I to ET 22-0005 Page 14 of 23
Attachment I to ET 22-0005 Page 15 of 23 RAI STSB-1 The licensees discussion regarding changes to Condition C does not contain information regarding the proposed TS non-logical connector or separating the component names in C.1.
Please discuss whether a TS logical connector OR and associated formatting are appropriate for proposed changes to Required Action C.1.
Response to RAI STSB-1 The proposed changes to Condition C in the response to RAI EEEB-1 item a. above address this RAI.
RAI EMIB-1 Provide how the SBO diesel fuel oil tanks are replenished.
Response to RAI EMIB-1 Each SBO DG has an associated fuel oil tank capacity to provide a minimum of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of run time at full load.
The following are the SBO DG fuel oil tank limits:
Low Level Alarm = 50% (14)
Minimum level for the SBO mission time = 86% (23.5)
SBO Mission Time Minimum Fuel Satisfied Light is lit at 90% (24.5)
Critical High Level Alarm = 95% (26.07)
Surveillance procedures STN KU-010, Station Blackout Diesel and Non-Safety AFW Pump Test, STN KU-001A, SBO DG to NB01 Functional Test, and STN KU-001B, SBO DG to NB02 Functional Test, include a restoration step to verify SBO DG fuel level greater than or equal to 91% (25).
Procedure CKL ZL-009, Site Reading Sheets, checks on a daily basis, the SBO DG fuel level, verifies the SBO Mission Time Minimum Fuel Satisfied Light is lit, and the Critical High Level Alarm is not in alarm. If fuel level is < 91%, the Control Room Supervisor is notified and fuel oil is added in accordance with Procedure SYS KU-123, Fueling Station Blackout Diesel Generators. Procedure SYS KU-123 provides the instructions to fill the SBO DG fuel oil tanks.
WCNOC maintains a fuel oil truck on site that is utilized for filling the SBO DG fuel oil tanks.
RAI EMIB-2 Provide the historical surveillance testing results for the SBO DGs.
Attachment I to ET 22-0005 Page 16 of 23 Response to RAI EMIB-2 Section 3.4.5 in Attachment I of Reference 1 describes the periodic surveillance testing of the SBO DG System. The below tabulates the historical surveillance results for the SBO DGs. Note that for procedure STN KU-010, Station Blackout Diesel and Non-Safety AFW Pump Test, the historical results are for the previous two years.
STN KU-010 DATE PERFORMED COMPLETE/
PARTIAL TEST DEFICIENCY/ADDITIONAL COMMENTS 2/2/2022 Complete 1/31/2022 Partial Partial for B SBO DG to support Work Order (WO) 21-470946-001.
1/5/2022 Complete Also performed for post maintenance testing on A SBO DG for annual maintenance under WO 21-474424-00.
1/5/2022 Partial Unloaded test for A SBO DG to support coolant flush.
12/10/2021 Partial Partial for C SBO DG to support WO 21-475640-006.
12/6/2021 Complete 11/3/2021 Partial Unloaded test for C SBO DG for post maintenance testing following troubleshooting under WO 21-475640-00.
11/2/2021 Partial Partial performance for loaded run of A and B SBO DGs.
Section 8.3 not performed for C SBO DG due to failure to start on 11/1/2021.
11/1/2021 Test was suspended when C SBO DG failed to start.
10/4/2021 Complete Louvers for the C SBO DG were stuck or nonfunctional.
Louvers were blocked open.
9/10/2021 Partial Partial performance for C SBO DG.
9/9/2021 Complete C SBO DG tripped during performance.
8/2/2021 Complete 7/6/2021 Complete 6/7/2021 Complete 4/10/2021 Complete 5/14/2021 Complete 3/10/2021 Complete 2/3/2021 Complete 1/4/2021 Complete 12/8/2020 Complete 11/2/2020 Complete 10/6/2020 Complete 9/10/2020 Complete 8/3/2020 Complete 7/7/2020 Complete 6/9/2020 Complete 5/6/2020 Complete 4/6/2020 Complete 3/12/2020 Complete 2/4/2020 Complete 1/8/2020 Complete
Attachment I to ET 22-0005 Page 17 of 23 STN KU-001A DATE PERFORMED COMPLETE/
PARTIAL TEST DEFICIENCY/ADDITIONAL COMMENTS 4/25/2014 Suspended Breaker PB0508 tripped when operating breaker NB00113 (Step 8.2.15).
4/28/2014 Complete 5/12/2018 Complete 5/5/2021 Complete STN KU-001B DATE PERFORMED COMPLETE/
PARTIAL TEST DEFICIENCY/ADDITIONAL COMMENTS 4/20/2015 Complete 11/15/2016 Complete 10/27/2019 Complete RAI APLC-1: Seismic Risk Insights Section 3.4.1, SBO DG System Description, of Attachment I to the LAR describes the SBO DG system. This section states that the SBO DG system consists of a missile barrier located outside of the protected area that contains the equipment required to provide power during a station blackout event. This section also states that the missile barrier is constructed to provide protection from tornado winds and tornado generated missiles. During its review, the NRC staff noted that the LAR does not discuss the impact of a seismic event on the SBO DGs or missile barrier housing the SBO DGs.
Section 4.1, External Hazards, of Attachment II to the LAR provides a qualitative discussion of the impact of a seismic event when a DG is out of service for the extended CT. This section describes the impact of a seismic event on the DGs and states that the DG building is seismically rugged.
Section 4.1 of Attachment II to the LAR states that the primary impact expected from a seismic event is a LOOP. This section also states that the seismically induced failures of the DGs are correlated, so one DG being out of service does not impact the seismic response. This section concludes that the change in risk associated with a DG being out of service for the extended CT is therefore equivalent to the change in risk from the internal events model for random failures.
Section 4.1 of Attachment II to the LAR does not discuss the impact of a seismic event on the SBO DGs. Based on the discussion in Section 3.4.1, of Attachment I to the LAR, the NRC staff notes that the SBO DGs may fail at lower seismic demands than the DGs. Specifically, a seismic event could result in a LOOP and a seismically induced correlated failure of all three SBO DGs without a corresponding loss of the DGs. In the context of the proposed change, this can result in a scenario involving a seismically induced LOOP combined with a seismically induced correlated failure of all SBO DGs and a random failure of the available DG with the other DG being out of service. In this scenario, it is unclear to the NRC staff that the change in seismic risk associated with a DG being out of service for the extended CT would be equivalent to the change in risk from the internal events model for random failures, as asserted in Section 4.1 of Attachment II to the LAR.
Attachment I to ET 22-0005 Page 18 of 23 Please address the following:
- a. Discuss seismic risk insights associated with the SBO DGs, including consideration of the NRC staff identified scenario, to support the LAR.
- b. Discuss consideration of risk mitigation actions to address seismic risk insights associated with the SBO DGs.
Response to RAI APLC-1
- a. The SBO DG System consists of a missile barrier located outside of the protected area that contains the necessary equipment required to provide reliable power to 4.16 kV Class 1E bus NB01 or NB02 during an SBO event, and to the non-safety auxiliary feedwater pump (NSAFP).
The foundation slab is designed for dead loads, live loads, tornado wind and missile loads, and seismic loads according to the International Building Code (IBC 2000). The discussions regarding the SBO missile barrier being seismically rugged is due to the design of the structure to withstand tornado winds and tornado generated missiles with 2 exterior walls and 4 thick foundation The missile barrier IBC seismic load was calculated and found to be bounded by the structural design for the Wind and Tornado Missile Loading.
The WCGS Design Basis for seismic events is discussed in updated safety analysis report (USAR) Section 3.1.2, which states, in part:
In the design and analysis performed for provision of protection of safety-related equipment from hazards and events (tornadoes, floods, missiles, pipe breaks, fires, and seismic events) which could reasonably be expected, the following assumptions were made:
- e. When evaluating the effects of any earthquake, no other major hazard or event is assumed, and no seismic Category I equipment is assumed to fail as a result of the earthquake. Certain nonseismic Category I components are designed and constructed to ensure that their failure will not reduce the functioning of a safety-related component to an unacceptable safety level. This criterion meets the intent of Regulatory Guide 1.29, Position C.2. Evaluation of component failure includes drop impact forces and secondary effects, such as spray and flooding from piping failure.
The SBO DGs are not credited in the event of a seismic event for design although they might be available. In the NRC scenario, a seismic event occurs that is strong enough to fail the SBO DGs but is not strong enough to fail the safety related DGs. This scenario occurs when one DG is in the extended Completion Time and the protected DG fails due to independent failure. This very specific scenario would have a very low probability of occurring during the 14 day timeframe of the extended Completion Time.
- b. Based on the robust design of the SBO DG System missile barrier and buried utilities, the risk analysis performed did not identify any specific risk mitigation actions/compensatory measures to address seismic risk insights associated with the SBO DGs. However, the TSs and various procedures as discussed below verify the availability and readiness of the SBO DGs to supply either train of safety related loads.
Attachment I to ET 22-0005 Page 19 of 23 Procedure CKL ZL-009, Site Reading Sheets, checks on a daily basis, the SBO DG fuel level and temperature, SBO various generator parameters (jacket water heater, control panel system lights, starting battery chargers, exhaust rain cap, crankcase oil level). The SBO Power Equipment Center (PEC) in the Switchgear Room checks on a daily basis the mobile unit charger lights, main charger voltage, room thermostat and temperature, and the MC4000 panel for alarms.
The SBO Battery Room is checked daily for battery charging, battery leakage, battery connection corrosion, and room temperature. The SBO enclosures, PEC Control Panel and Switchgear area, and battery cubicle are checked daily for leaks, cleanliness, lighting, etc.
Procedure AI 22C-013, Protected Equipment Program, provides guidance for protecting equipment in order to minimize plant risk. The intent of protecting systems and components is to provide additional administrative barriers to guard against inadvertently rendering a component or system, which is important to unit risk and nuclear safety, inoperable or unavailable.
Attachment A of this procedure provides examples of equipment that should be protected. With a DG inoperable, this procedure identifies the SBO DGs as equipment to be protected. Protected equipment and systems are to be clearly identified in the field to prevent inadvertent work on or near the protected equipment. Protected equipment is identified by such means as physical barriers or postings. The procedure specifies that upon posting of protected equipment and during Operations watchstander rounds, a check is made that there is nothing in the area (e.g.,
scaffolding) that could interfere with the functioning of the protected equipment.
When a DG is declared inoperable, the proposed Required Action B.2 requires verifying the availability of the required SBO DGs. The Completion Time associated with Required Action B.2 is 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> and once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> thereafter. The proposed TS Bases identifies in part that this verification includes verifying fuel oil tank level and supporting system parameters for starting and operating the required SBO DGs.
RAI APLC-2: Fire Risk Insights Section 3.7, Risk Management/Work Control and Scheduling, of Attachment I to the LAR describes how the risk impact of maintenance, testing, and equipment outages is assessed. This section states that an On-Line Nuclear Safety and Generation Risk Assessment is completed for the current weekly schedule and that maintenance and testing activities added to the weekly schedule are assessed for their impact upon the existing On-Line Nuclear Safety and Generation Risk Assessment. This section also states that online daily maintenance and testing activities are planned, scheduled, and conducted in a manner to ensure both commercial and nuclear safety issues are assessed and the associated risks are managed. This section further states that risk assessment and management is accomplished, in part, by developing compensatory measures to manage and minimize the operational risks associated with planned or emergent activities that are categorized as risk significant.
Section 4.1, External Hazards, of Attachment II to the LAR provides a qualitative discussion of the impact of fire events when a DG is out of service for the extended CT. This section discusses that the fire risk associated with a DG being out of service for the extended CT will increase for areas where a fire can damage the capability to receive offsite power to the safeguards buses.
This section states that the only area where an internal fire can cause a LOOP is the communications corridor. During its review, the NRC staff noted that the LAR does not discuss if the SBO DGs or their associated cables, including those supplying the safeguard buses, could
Attachment I to ET 22-0005 Page 20 of 23 be affected by a fire in the communications corridor. Further, it is unclear to the staff if the On-Line Nuclear Safety and Generation Risk Assessment considers the risk of a fire in the communications corridor causing a LOOP.
Please address the following:
- a. Clarify if the On-Line Nuclear Safety and Generation Risk Assessment considers the risk of a fire in the communications corridor causing a LOOP.
- b. Discuss fire risk insights associated with the communications corridor and the SBO DGs or their associated cables, including those supplying the safeguard buses, to support the LAR.
- c. Discuss consideration of risk mitigation actions to address fire risk insights associated with the communications corridor.
Response to RAI APLC-2
- a. Procedure AP 22C-003, On-Line Nuclear Safety and Generation Risk Assessment, specifies that the Fire Protection Group will review the On-Line Nuclear Safety and Generation Risk Assessment considering all maintenance and testing activities reflected in the schedule to determine their affect upon fire risk significant areas. The procedure identifies the fire risk significant components, affected fire areas, and pre-determined risk mitigating actions.
Calculation XX-E-013, Post-Fire Safe Shutdown (PFSSD) Analysis, provides the assumptions and methodology utilized to determine which components and systems provide the functions necessary to achieve and maintain PFSSD. The calculation demonstrates WCGSs ability to achieve and maintain PFSSD in the event of a fire in any area of the plant. Appendix 2, Fire Induced Loss of Off-Site Power, identifies the fire areas where a LOOP may be initiated by fire damage. In the event of a fire in the communications corridor (Fire Area CC-1/IPEEE fire areas CC-IF and CC-ID), PFSSD will be performed with equipment powered from NB01 and/or NB02.
The train A DG will supply power to NB01. The train B DG will supply power to NB02.
A review of the cable routing associated with the SBO DG System identified three cables that could be affected by a fire in the communications corridor (RM 3402). Since the proposed 14 day Completion Time is based on the availability of two SBO DGs, AP 22C-003 will be revised to include the necessary risk mitigation actions/compensatory measures for Fire Area CC-1 associated with a DG being out of service.
The WCGS Individual Plant Examination of External Events (IPEEE) evaluation (Reference 5) indicates the only location in which a fire could cause a complete loss of offsite power event is the communications corridor. A fire in this area could damage cables causing a loss of power to both engineered safeguards features (ESF) transformers XNB01 and XNB02 as well as a loss of power from the #7 transformer, resulting in a station LOOP condition. Further, a partial LOOP was considered for several of the yard transformers and the turbine building general area. A fire in these areas is considered to fail one of the two main offsite power supplies.
- b. The WCGS IPEEE evaluation (Reference 5) for internal fires at power determined that the likelihood of a fire resulting in a complete SBO is low. The risk insights show that there is only one location where a complete LOOP could occur (the communications corridor) and that the
Attachment I to ET 22-0005 Page 21 of 23 ability of the plant to avoid a Licensing Basis SBO event from LOOP scenarios is dependent on the availability of the dedicated DG (SBO DGs are not credited in the Licensing Basis SBO event).
Since the completion of the IPEEE evaluation, WCNOC has installed the SBO DGs which are capable of being started, aligned to either safety bus, and are capable of supplying the necessary AC power to safe shutdown loads. The contribution from the SBO DGs to risk-reduction for otherwise SBO conditions is significant.
- c. In procedure AP 10-106 Fire Preplans, Appendix B shows that the fire loading in each of the areas in the communications corridor is low.
A review of the cable routing associated with the SBO DG System identified three cables that could be affected by a fire in the communications corridor (RM 3402). Since the proposed 14 day Completion Time is based on the availability of two SBO DGs, AP 22C-003 will be revised to include the necessary risk mitigation actions/compensatory measures for Fire Area CC-1 associated with a DG being out of service.
RAI APLC-3: Common Cause and Human Reliability Risk Insights Section 3.4.2, SBO DG - AC System Analysis, of Attachment I to the LAR describes an analysis of the SBO DGs. This section states that three SBO DGs can successfully power all LOOP loads and two SBO DGs can successfully power the minimum required safe shutdown loads provided the loads are manually started at least 30 seconds between starts. This section also states that plant operating procedures contain guidance for manually starting the safe shutdown loads. The NRC staff understands these statements to mean that a single SBO DG cannot successfully power the minimum required safe shutdown loads.
Section 5.11, Risk Insights, of Attachment II to the LAR discusses the licensees risk insights supporting this LAR. Based on its review of these risk insights, it is unclear to the NRC staff if the common-cause failure of SBO DGs and the human reliability to start the SBO DGs and power the safe shutdown loads were considered in the risk insights used to support the LAR.
Please address the following:
- a. Discuss how the common-cause failure of SBO DGs and the human reliability to start the SBO DGs and power the safe shutdown loads were included in the risk insights used to support the LAR.
- b. Discuss consideration of risk mitigation actions to address risk insights associated with the common-cause failure of SBO DGs and the human reliability to start the SBO DGs and power the safe shutdown loads.
Response to RAI APLC-3
- a. The WCGS Probabilistic Risk Assessment (PRA) requires two out of three SBO DGs and an operator action to start and align the necessary SBO DGs to one safety bus for success (OPA-SBO-DG). Further, the WCGS PRA evaluates common cause failures (CCF) for combinations of two and three SBO DGs. As discussed in Attachment I to ET 21-0004 in Section 3.10.1.d, no new common cause failure mechanisms are created as a result of the proposed changes.
Attachment I to ET 22-0005 Page 22 of 23
- b. The risk analysis performed did not identify any specific risk mitigation actions/compensatory measures to address common cause and human reliability risks associated with the SBO DGs.
However, the TSs and various procedures as discussed below verify the availability and readiness of the SBO DGs to supply either train of safety related loads. The periodic testing of the SBO DGs is discussed in Section 3.4.5 of Reference 1.
When a DG is declared inoperable, the proposed Required Action B.2 requires verifying the availability of the required SBO DGs. The Completion Time associated with Required Action B.2 is 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> and once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> thereafter. The proposed TS Bases identifies in part that this verification includes verifying fuel oil tank level and supporting system parameters for starting and operating the required SBO DGs.
Procedure CKL ZL-009, Site Reading Sheets, checks on a daily basis, the SBO DG fuel level and temperature, SBO various generator parameters (jacket water heater, control panel system lights, starting battery chargers, exhaust rain cap, crankcase oil level). The SBO PEC in the Switchgear Room checks on a daily basis the mobile unit charger lights, main charger voltage, room thermostat and temperature, and the MC4000 panel for alarms. The SBO Battery Room is checked daily for battery charging, battery leakage, battery connection corrosion, and room temperature. The SBO enclosures, PEC Control Panel and Switchgear area, and battery cubicle are checked daily for leaks, cleanliness, lighting, etc.
Procedural guidance to address contingency issues is provided in the following procedures.
Procedures SYS KU-121, Energizing NB01 from Station Blackout Diesel Generators, and SYS KU-122, Energizing NB02 from Station Blackout Diesel Generators, provide guidance for:
Normal remote starting and loading of the SBO DGs using the programmable logic control/human-machine interface (PLC/HMI) panel.
Manual starting and loading of the SBO DGs if required based on a complete PLC/HMI panel failure.
Locally starting one SBO DG on a loss of control power, which would re-establish control power to the other SBO DGs.
Procedure SYS KU-124, SBO Generator Local or Manual Operations, provides for local operations for SBO DG starting and loading in the event remote start capability is lost. This procedure includes guidance for:
Using the staged mobile PEC battery cart to jump start an SBO DG if the installed batteries fail.
Each SBO DG is equipped with a Battleswitch to bypass normal engine and generator trips. Use of the Battleswitch is at the direction of the Site Emergency Manager to prevent or lessen the severity of reactor core damage.
Resetting the PLC controls.
Attachment I to ET 22-0005 Page 23 of 23
References:
- 1. WCNOC letter ET 21-0004 from S. L. Smith, WCNOC, to USNRC, License Amendment Request - Diesel Generator Completion Time Extension for Technical Specification 3.8.1, AC Sources - Operating, September 29, 2021. ADAMS Accession No. ML21272A369.
- 2. Electronic mail from S. A. Lee, USNRC, to J. Turner, WCNOC, Request for additional information - Wolf Creek Request for additional information - Wolf Creek request to revise diesel generator completion time (EPID: L-2021-LLA-0173), February 23, 2022. ADAMS Accession No. ML22055A114.
- 3. Letter from M. Mahoney, USNRC, to T. Simril, Duke Energy Carolinas, LLC, Catawba Nuclear Station, Units 1 and 2 - Issuance of Amendment Nos. 304 and 300 to Technical Specification 3.8.1, AC Sources - Operating (CAC NOS. MF9667, MF9668 MF9671, MF9672 and EPID NOS. L-2017-LLA-0256 and L-2017-LLA-0257), August 27, 2019.
ADAMS Accession No. ML19212A655.
- 4. Letter from M. Mahoney, USNRC, to T. D. Ray, Duke Energy Carolinas, LLC, McGuire Nuclear Station, Units 1 and 2 - Issuance of Amendment Nos. 314 and 293 to Technical Specification 3.8.1, AC Sources - Operating (CAC NOS. MF9667, MF9668 MF9671, MF9672 and EPID NOS. L-2017-LLA-0256 and L-2017-LLA-0257), June 28, 2019. ADAMS Accession No. ML19126A030.
- 5. Wolf Creek Generating Station, Individual Plant Examination of External Events (IPEEE),
June 1995.
Attachment II to ET 22-0005 Page 1 of 7 Revised WCGS Technical Specification 3.8.1 Pages (Markup)
AC Sources - Operating 3.8.1 Wolf Creek - Unit 1 3.8-2 Amendment No. 123, 163 ACTIONS (continued)
CONDITION REQUIRED ACTION COMPLETION TIME A.
(continued)
Declare required feature(s) with no offsite power available inoperable when its redundant required feature(s) is inoperable.
AND A.3 Restore offsite circuit to OPERABLE status.
24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> from discovery of no offsite power to one train concurrent with inoperability of redundant required feature(s)
NOTE-------
A Completion Time of 10 days from discovery of failure to meet the LCO may be used with the 7 day Completion Time of Required Action B.4.2.2 for an inoperable DG.
72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> AND 6 days from discovery of failure to meet LCO B.
One DG inoperable.
B.1 Perform SR 3.8.1.1 for the offsite circuit(s).
AND 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> AND Once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> thereafter (continued) 17 B.2 Verify the required Station Blackout (SBO) DGs are available.
1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> AND Once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> thereafter AND Attachment II to ET 22-0005 Page 2 of 7
AC Sources - Operating 3.8.1 Wolf Creek - Unit 1 3.8-3 Amendment No. 123, 163 ACTIONS (continued)
CONDITION REQUIRED ACTION COMPLETION TIME B.
(continued)
B.2
NOTE--------------
In MODES 1, 2, and 3, the turbine driven auxiliary feedwater pump is considered a required redundant feature.
Declare required feature(s) supported by the inoperable DG inoperable when its required redundant feature(s) is inoperable.
AND B.3.1 Determine OPERABLE DG is not inoperable due to common cause failure.
OR B.3.2
NOTE--------------
The Required Action of B.3.2 is satisfied by the automatic start and sequence loading of the DG.
Perform SR 3.8.1.2 for OPERABLE DG.
AND 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> from discovery of Condition B concurrent with inoperability of redundant required feature(s) 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 24 hours (continued) 3 4
Attachment II to ET 22-0005 Page 3 of 7
AC Sources - Operating 3.8.1 Wolf Creek - Unit 1 3.8-4 Amendment No. 123, 163 ACTIONS (continued)
CONDITION REQUIRED ACTION COMPLETION TIME B.
(continued)
NOTE-------------------
Required Action B.4.2.1 and B.4.2.2 are only applicable for planned maintenance and may be used once per cycle per DG.
B.4.1 Restore DG to OPERABLE status.
OR B.4.2.1 Verify the required Sharpe Station gensets are available.
AND B.4.2.2 Restore DG to OPERABLE status.
72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> AND 6 days from discovery of failure to meet LCO Once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> 7 days AND 10 days from discovery of failure to meet LCO C.
Required Action B.4.2.1 and associated Completion Time not met.
C.1 Restore DG to OPERABLE status.
72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> (continued) 14 days 17 5
Attachment II to ET 22-0005 Page 4 of 7 INSERT 3.8-4
INSERT 3.8-4 CONDITION REQUIRED ACTION COMPLETION TIME C.
Required Action B.2 and associated Completion Time not met.
C.1 Restore DG to OPERABLE status.
OR C.2 Restore required SBO DGs to available status.
72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> from Condition B entry OR 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> from Condition B entry 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> concurrent with unavailability of required SBO DGs 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> from Condition B entry OR 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> from Condition B entry 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> concurrent with unavailability of required SBO DGs Attachment II to ET 22-0005 Page 5 of 7
AC Sources - Operating 3.8.1 Wolf Creek - Unit 1 3.8-5 Amendment No. 123, 163 ACTIONS (continued)
CONDITION REQUIRED ACTION COMPLETION TIME D.
Two offsite circuits inoperable.
D.1
NOTE--------------
In MODES 1, 2, and 3, the turbine driven auxiliary feedwater pump is considered a required redundant feature.
Declare required feature(s) inoperable when its redundant required feature(s) is inoperable.
AND D.2 Restore one offsite circuit to OPERABLE status.
12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> from discovery of Condition D concurrent with inoperability of redundant required features 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> E.
One offsite circuit inoperable.
AND One DG inoperable.
NOTE----------------------
Enter applicable Conditions and Required Actions of LCO 3.8.9, "Distribution Systems - Operating,"
when Condition E is entered with no AC power source to any train.
E.1 Restore offsite circuit to OPERABLE status.
OR E.2 Restore DG to OPERABLE status.
12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> 12 hours F.
Two DGs inoperable.
F.1 Restore one DG to OPERABLE status.
2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> (continued)
NO CHANGES THIS PAGE. INFORMATION ONLY.
Attachment II to ET 22-0005 Page 6 of 7
AC Sources - Operating 3.8.1 Wolf Creek - Unit 1 3.8-6 Amendment No. 123, 163 ACTIONS (continued)
CONDITION REQUIRED ACTION COMPLETION TIME G.
One load shedder and emergency load sequencer inoperable.
G.1 Declare affected DG and offsite circuit inoperable.
AND G.2 Restore load shedder and emergency load sequencer to OPERABLE status.
Immediately 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> H.
Required Action and associated Completion Time of Condition A, C, D, E, F, or G not met.
OR Required Actions B.1, B.2, B.3.1, B.3.2, B.4.1, and B.4.2.2 and associated Completion Time not met.
H.1 Be in MODE 3.
AND H.2 Be in MODE 5.
6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> 36 hours I.
Three or more required AC sources inoperable.
I.1 Enter LCO 3.0.3.
Immediately B.3, B.4.1, B.4.2, and B.5 Attachment II to ET 22-0005 Page 7 of 7
Attachment III to ET 22-0005 Page 1 of 18 Revised WCGS Technical Specification 3.8.1 Bases Pages (Markup) (for information only)
AC Sources - Operating B 3.8.1 Wolf Creek - Unit 1 B 3.8.1-2 Revision 88 BASES BACKGROUND Power (LOP) Diesel Generator (DG) Start Instrumentation. After the DG (continued) has started, it will automatically tie to its respective bus after offsite power is tripped as a consequence of ESF bus undervoltage or degraded voltage, independent of or coincident with an SI signal. The DGs will also start and operate in the standby mode without tying to the ESF bus on an SI signal alone. Following the trip of offsite power, a LSELS strips non-essential loads from the ESF bus. When the DG is tied to the ESF bus, essential loads are then sequentially connected to its respective ESF bus by the load sequencer. The sequencing logic controls the permissive and starting signals to motor breakers to prevent overloading the DG by automatic load application.
In the event of a loss of preferred power, the ESF electrical loads are automatically connected to the DGs in sufficient time to provide for safe reactor shutdown and to mitigate the consequences of a Design Basis Accident (DBA) such as a loss of coolant accident (LOCA).
Certain required unit loads are returned to service in a predetermined sequence in order to prevent overloading the DG in the process. Within 1 minute after the initiating signal is received, all loads needed to recover the unit or maintain it in a safe condition are returned to service.
Ratings for Train A and Train B DGs satisfy the requirements of Regulatory Guide 1.9 (Ref. 3). The continuous service rating of each DG is 6201 kW with 10% overload permissible for up to 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> in any 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period. The ESF loads that are powered from the 4.16 kV ESF buses are listed in Reference 2.
APPLICABLE The initial conditions of DBA and transient analyses in the USAR, SAFETY ANALYSES Chapter 6 (Ref. 4) and Chapter 15 (Ref. 5), assume ESF systems are OPERABLE. The AC electrical power sources are designed to provide sufficient capacity, capability, redundancy, and reliability to ensure the availability of necessary power to ESF systems so that the fuel, Reactor Coolant System (RCS), and containment design limits are not exceeded.
These limits are discussed in more detail in the Bases for Section 3.2, Power Distribution Limits; Section 3.4, Reactor Coolant System (RCS);
and Section 3.6, Containment Systems.
The OPERABILITY of the AC electrical power sources is consistent with the initial assumptions of the Accident analyses and is based upon meeting the design basis of the unit. This results in maintaining at least one train of the onsite or offsite AC sources OPERABLE during Accident conditions in the event of:
- a.
An assumed loss of all offsite power or all onsite AC power; and INSERT B 3.8.1-2 Attachment III to ET 22-0005 Page 2 of 18
INSERT B 3.8.1-2 The Station Blackout (SBO) DG System consists of three non-safety related DGs that are capable of supplying essential loads on ESF buses NB01 and NB02. The SBO DG System is made available to support extended Completion Times in the event of an inoperable DG. Only two SBO DGs are required to successfully start the minimum required safe shutdown loads. The SBO DGs are made available as a defense-in-depth supplemental source of AC power to mitigate a loss of offsite power event. The SBO DGs would remain disconnected from the Class 1E AC Distribution System unless required during a loss of offsite power or during a functional load test.
Attachment III to ET 22-0005 Page 3 of 18
AC Sources - Operating B 3.8.1 Wolf Creek - Unit 1 B 3.8.1-6 Revision 25 BASES ACTIONS A.2 (continued)
- b.
A required feature on the other train is inoperable and not in the safeguards position.
If at any time during the existence of Condition A (one offsite circuit inoperable) a redundant required feature subsequently becomes inoperable, this Completion Time begins to be tracked.
Discovering no offsite power to one train of the onsite Class 1E Electrical Power Distribution System coincident with one or more inoperable required support or supported features, or both, that are associated with the other train that has offsite power, results in starting the Completion Times for the Required Action. Twenty-four hours is acceptable because it minimizes risk while allowing time for restoration before subjecting the unit to transients associated with shutdown.
The remaining OPERABLE offsite circuit and DGs are adequate to supply electrical power to Train A and Train B of the onsite Class 1E Distribution System. The 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> Completion Time takes into account the component OPERABILITY of the redundant counterpart to the inoperable required feature. Additionally, the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> Completion Time takes into account the capacity and capability of the remaining AC sources, a reasonable time for repairs, and the low probability of a DBA occurring during this period.
A.3 According to Regulatory Guide 1.93 (Ref. 6), operation may continue in Condition A for a period that should not exceed 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. With one offsite circuit inoperable, the reliability of the offsite system is degraded, and the potential for a loss of offsite power is increased, with attendant potential for a challenge to the unit safety systems. In this Condition, however, the remaining OPERABLE offsite circuit and DGs are adequate to supply electrical power to the onsite Class 1E Distribution System.
The 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> Completion Time takes into account the capacity and capability of the remaining AC sources, a reasonable time for repairs, and the low probability of a DBA occurring during this period.
The second Completion Time for Required Action A.3 establishes a limit on the maximum time allowed for any combination of required AC power sources to be inoperable during any single contiguous occurrence of failing to meet the LCO. If Condition A is entered while, for instance, a DG is inoperable and that DG is subsequently returned OPERABLE, the LCO may already have been not met for up to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. This could lead to a 14 days Attachment III to ET 22-0005 Page 4 of 18
AC Sources - Operating B 3.8.1 Wolf Creek - Unit 1 B 3.8.1-7 Revision 26 BASES ACTIONS A.3 (continued) total of 144 hours0.00167 days <br />0.04 hours <br />2.380952e-4 weeks <br />5.4792e-5 months <br />, since initial failure to meet the LCO, to restore the offsite circuit. At this time, a DG could again become inoperable and an additional 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> allowed prior to complete restoration of the LCO. The 6 day Completion Time provides a limit on the time allowed in a specified condition after discovery of failure to meet the LCO. Although highly unlikely, this could continue indefinitely if not limited. This limit is considered reasonable for situations in which Conditions A and B are entered concurrently. This limits the time the plant can alternate between Conditions A, B, and E (see Completion Time Example 1.3-3). The "AND" connector between the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> and 6 day Completion Times means that both Completion Times apply simultaneously, and the more restrictive Completion Time must be met.
Tracking the 6 day Completion Time is a requirement for beginning the Completion Time clock that is in addition to the normal Completion Time requirements. With respect to the 6 day Completion Time, the time zero is specified as beginning at the time LCO 3.8.1 was initially not met, instead of at the time Condition A was entered. This results in the requirement, when in this Condition, to track the time elapsed from both the Condition A time zero, and the time zero when LCO 3.8.1 was initially not met. Refer to Section 1.3, Completion Times, for a more detailed discussion of the purpose of the from discovery of failure to meet the LCO portion of the Completion Time.
The Completion Time is modified by a Note. The Note modifies the Completion Time and allows 10 days from discovery of failure to meet the LCO during the use of the 7 day Completion Time in Required Action B.4.2.2.
The 10 day Completion Time specified in the Note establishes a limit on the maximum time allowed for any combination of required AC power sources to be inoperable during any single contiguous occurrence of failing to meet the LCO. If Condition A is entered while, for instance, a DG is inoperable using the 7 day Completion Time of Required Action B.4.2.2 and that DG is subsequently restored OPERABLE, the LCO may already have been not met for up to 7 days. This could lead to a total of 10 days since initial failure to meet the LCO, to restore the offsite circuit. At this time, a DG could again become inoperable and an additional 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> allowed prior to complete restoration of the LCO. Although highly unlikely, this could continue indefinitely if not limited. The 10 day Completion Time provides a limit on time allowed in a specified condition after discovery of failure to meet the LCO. This limit is considered reasonable for situations in which Conditions A and B are entered concurrently. This limits the time the plant can alternate between Conditions A, B, and D (see Completion Time Example 1.3-3).
17 days 14 days 17 17 14 Attachment III to ET 22-0005 Page 5 of 18
AC Sources - Operating B 3.8.1 Wolf Creek - Unit 1 B 3.8.1-8 Revision 35 BASES ACTIONS A.3 (continued)
Tracking the 10 day Completion Time is a requirement for beginning the Completion Time clock that is in addition to the normal Completion Time requirements. With respect to the 10 day Completion Time, the time zero is specified as beginning at the time LCO 3.8.1 was initially not met, instead of at the time Condition A was entered. This results in the requirement, when in this Condition, to track the time elapsed from both the Condition A time zero, and the time zero when LCO 3.8.1 was initially not met. Refer to Section 1.3, Completion Times, for a more detailed discussion of the purpose of the from discovery of failure to meet the LCO portion of the Completion Time.
B.1 To ensure a highly reliable power source remains with an inoperable DG, it is necessary to verify the availability of the offsite circuits on a more frequent basis. Since the Required Action only specifies "perform," a failure of SR 3.8.1.1 acceptance criteria does not result in a Required Action being not met. However, if a circuit fails to pass SR 3.8.1.1, it is inoperable. Upon offsite circuit inoperability, additional Conditions and Required Actions must then be entered.
B.2 Required Action B.2 is intended to provide assurance that a loss of offsite power, during the period that a DG is inoperable, does not result in a complete loss of safety function of critical redundant required features.
These redundant required features are those that are assumed to function to mitigate an accident, coincident with a loss of offsite power, in the safety analyses, such as the Emergency Core Cooling System and Auxiliary Feedwater System. These redundant features do not include monitoring requirements, such as Post Accident Monitoring and Remote Shutdown. These features are powered from the redundant AC electrical power train. This includes motor driven auxiliary feedwater pumps.
Single train systems, other than the turbine driven auxiliary feedwater pump, are not included in this Condition. A Note is added to this Required Action stating that in MODES 1, 2, and 3, the turbine driven auxiliary feedwater pump is considered a required redundant feature. The reason for the Note is to confirm the OPERABILITY of the turbine driven auxiliary feedwater pump in this Condition, since the remaining OPERABLE motor driven auxiliary feedwater pump is not by itself capable of providing 100%
of the auxiliary feedwater flow assumed in the safety analysis. Redundant required feature failures consist of inoperable features associated with a train, redundant to the train that has an inoperable DG.
INSERT B 3.8.1-8 3
Attachment III to ET 22-0005 Page 6 of 18
INSERT B 3.8.1-8 B.2 In order to extend the Completion Time for an inoperable DG from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 14 days, the required SBO DGs must be verified available within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> upon entry into TS 3.8.1, Condition B, and every 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> thereafter. SBO DG availability requires that:
- a.
A start/loaded test has been performed within 30 days of entry into the extended Completion Time. This portion of the Required Action evaluation is performed one time and is met with an administrative verification of this prior to a planned removal of a DG from service or after an emergent DG outage; and
- b.
Fuel oil tank level for each required SBO DG is verified locally to be 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> supply (SBO Mission Time Minimum Fuel Satisfied Light); and
- c.
Supporting system parameters for starting and operating each required SBO DG are verified to be within required limits for functional availability (e.g., battery state of charge).
Only two SBO DGs are required to successfully start the minimum required safe shutdown loads. The SBO DG System is not used to extend the Completion Time for more than one inoperable DG at any one time.
Attachment III to ET 22-0005 Page 7 of 18
AC Sources - Operating B 3.8.1 Wolf Creek - Unit 1 B 3.8.1-9 Revision 42 BASES ACTIONS B.2 (continued)
The Completion Time for Required Action B.2 is intended to allow the operator time to evaluate and repair any discovered inoperabilities. This Completion Time also allows for an exception to the normal "time zero" for beginning the allowed outage time "clock." In this Required Action, the Completion Time only begins on discovery that both:
- a.
An inoperable DG exists; and
- b.
A required feature on the other train (Train A or Train B) is inoperable and not in the safeguards position.
If at any time during the existence of this Condition (one DG inoperable) a required feature subsequently becomes inoperable, this Completion Time would begin to be tracked.
Discovering one required DG inoperable coincident with one or more inoperable required support or supported features, or both, that are associated with the OPERABLE DG, results in starting the Completion Time for the Required Action. Four hours from the discovery of these events existing concurrently is acceptable because it minimizes risk while allowing time for restoration before subjecting the unit to transients associated with shutdown.
In this Condition, the remaining OPERABLE DG and offsite circuits are adequate to supply electrical power to the onsite Class 1E Distribution System. Thus, on a component basis, single failure protection for the required feature's function may have been lost; however, function has not been lost. The 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> Completion Time takes into account the OPERABILITY of the redundant counterpart to the inoperable required feature. Additionally, the 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> Completion Time takes into account the capacity and capability of the remaining AC sources, a reasonable time for repairs, and the low probability of a DBA occurring during this period.
B.3.1 and B.3.2 Required Action B.3.1 provides an allowance to avoid unnecessary testing of OPERABLE DG. If it can be determined that the cause of the inoperable DG does not exist on the OPERABLE DG, SR 3.8.1.2 does not have to be performed. If the cause of inoperability exists on the other DG, it would be declared inoperable upon discovery and Condition F of LCO 3.8.1 would be entered. Once the failure is repaired, the common cause failure no longer exists, and Required Action B.3.1 is satisfied. If the cause of the initial inoperable DG cannot be confirmed not to exist on 3
4 4
Attachment III to ET 22-0005 Page 8 of 18
AC Sources - Operating B 3.8.1 Wolf Creek - Unit 1 B 3.8.1-10 Revision 39 BASES ACTIONS B.3.1 and B.3.2 (continued) the remaining DG, performance of SR 3.8.1.2 suffices to provide assurance of continued OPERABILITY of that DG. Required Action B.3.2 is modified by a Note stating that it is satisfied by the automatic start and sequence loading of the DG. The Note indicates that an additional start of the DG for test purposes only, is not required if the DG has automatically started and loaded following a loss of the offsite power source to its respective bus (Ref. 18).
In the event the inoperable DG is restored to OPERABLE status prior to completing either B.3.1 or B.3.2, the plant corrective action program will continue to evaluate the common cause possibility. This continued evaluation, however, is no longer under the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> constraint imposed while in Condition B.
According to Generic Letter 84-15 (Ref. 7), 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> is reasonable to confirm that the OPERABLE DG is not affected by the same problem as the inoperable DG.
B.4.1, B.4.2.1, and B.4.2.2 In Condition B, the remaining OPERABLE DG and offsite circuits are adequate to supply electrical power to the onsite Class 1E Distribution System. With a DG inoperable, the inoperable DG must be restored to OPERABLE status within the applicable, specified Completion Time.
The Completion Time of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> for Required Action B.4.1 applies when a DG is discovered or determined to be inoperable, such as due to a component or test failure, and requires time to effect repairs, or it may apply when a DG is rendered inoperable for the performance of maintenance during applicable MODES. The 72-hour Completion Time takes into account the capacity and capability of the remaining AC sources, reasonable time for repairs, and the low probability of a DBA during this period.
The second Completion Time for Required Action B.4.1 also establishes a limit on the maximum time allowed for any combination of required AC power sources to be inoperable during any single contiguous occurrence of failing to meet the LCO. If Condition B is entered while, for instance, an offsite circuit is inoperable, the LCO may already have been not met for up to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. If the offsite circuit is restored to OPERABLE status within the required 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, this could lead to a total of 144 hours0.00167 days <br />0.04 hours <br />2.380952e-4 weeks <br />5.4792e-5 months <br />, since initial failure to meet the LCO, to restore the compliance with the LCO (i.e.,
restore the DG). At this time, an offsite circuit could again become inoperable and an additional 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> allowed prior to complete 4
4 B.5 INSERT B 3.8.1-10 Attachment III to ET 22-0005 Page 9 of 18
INSERT B 3.8.1-10 In Condition B, the remaining OPERABLE DGs and offsite circuits are adequate to supply electrical power to the onsite Class 1E Distribution System. The 14 day Completion Time takes into account the capacity and capability of the remaining AC sources (including the required SBO DGs), a reasonable time for repairs, and the low probability of a DBA occurring during this period.
When one DG is inoperable due to either preplanned maintenance (preventive or corrective) or unplanned corrective maintenance work, the Completion Time can be extended from 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> to 14 days if the required SBO DGs are verified available for backup operation in accordance with Required Action B.2. The 14 day Completion Time for an inoperable DG will be used no more than once in an 18-month period on a per DG basis to perform DG planned maintenance.
The second Completion Time for Required Action B.5 establishes a limit on the maximum time allowed for any combination of required AC power sources to be inoperable during any single contiguous occurrence of failing to meet the LCO. If Condition B is entered while, for instance, an offsite circuit is inoperable and that circuit is subsequently restored OPERABLE, the LCO may already have been not met for up to 14 days. This could lead to a total of 17 days, since initial failure to meet the LCO, to restore the DGs. At this time, an offsite circuit could again become inoperable, the DGs restored OPERABLE, and an additional 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> (for a total of 20 days) allowed prior to complete restoration of the LCO. The 17 day Completion Time provides a limit on time allowed in a specified condition after discovery of failure to meet the LCO. This limit is considered reasonable for situations in which Conditions A and B are entered concurrently. This limits the time the plant can alternate between Conditions A, B, and D (see Completion Time Example 1.3-3). The AND connector between the 14 day and 17 day Completion Times means that both Completion Times apply simultaneously, and the more restrictive Completion Time must be met.
Tracking the 17 day Completion Time is a requirement for beginning the Completion Time clock that is in addition to the normal Completion Time requirements. With respect to the 17 day Completion Time, the time zero is specified as beginning at the time LCO 3.8.1 was initially not met, instead of at the time Condition B was entered. This results in the requirement, when in this Condition, to track the time elapsed from both the Condition B time zero, and the time zero when LCO 3.8.1 was initially not met. Refer to Section 1.3, Completion Times, for a more detailed discussion of the purpose of the from discovery of failure to meet the LCO portion of the Completion Time.
Administrative controls are required whenever Condition B is entered for a planned or unplanned DG outage that will extend beyond 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. Administrative controls applied ensure or require that:
- a.
Weather conditions are conducive to an extended DG Completion Time.
- b.
The offsite power supply and switchyard condition are conducive to an extended DG Completion Time, which includes ensuring that switchyard access is restricted and no elective maintenance within the switchyard is performed that would challenge offsite power availability. Elective maintenance or testing that would challenge offsite power availability is that activity that could result in an electrical power distribution system (offsite circuit or transmission network) transient or make the offsite circuit(s) unavailable Attachment III to ET 22-0005 Page 10 of 18
or inoperable (Reference 19). The operational risk assessment procedure provides a list of equipment that could challenge offsite power availability.
- c.
No equipment or systems assumed to be available for supporting the extended DG Completion Time are removed from service. The equipment or systems assumed to be available (including required support systems, i.e., associated room coolers, etc.) are as follows:
- Auxiliary Feedwater System (three trains)
- Component Cooling Water System (both trains and all four pumps)
- Essential Service Water System (both trains)
- Emergency Core Cooling System (two trains).
Attachment III to ET 22-0005 Page 11 of 18
AC Sources - Operating B 3.8.1 Wolf Creek - Unit 1 B 3.8.1-11 Revision 36 BASES ACTIONS B.4.1, B.4.2.1, and B4.2.2 (continued) time allowed in a specified condition after discovery of failure to meet the LCO. This limit is considered reasonable for situations in which Conditions A and B are entered concurrently. This limits the time the plant can alternate between Conditions A, B, and E (see Completion Time Example 1.3-3). The "AND" connector between the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> and 6 day Completion Times means that both Completion Times apply simultaneously, and the more restrictive Completion Time must be met.
Tracking the 6 day Completion Time is a requirement for beginning the Completion Time clock that is in addition to the normal Completion Time requirements. With respect to the 6 day Completion Time, the time zero is specified as beginning at the time LCO 3.8.1 was initially not met, instead of at the time Condition B was entered. This results in the requirement, when in this Condition, to track the time elapsed from both the Condition B time zero, and the time zero when LCO 3.8.1 was initially not met. Refer to Section 1.3, Completion Times, for a more detailed discussion of the purpose of the from discovery of failure to meet the LCO portion of the Completion Time.
The Required Actions are modified by a Note that states that Required Actions B.4.2.1 and B.4.2.2 are only applicable for voluntary planned maintenance and may be used once per cycle per DG. Required Actions B.4.2.1 and B.4.2.2 only applies when a DG is declared or rendered inoperable for the performance of voluntary, planned maintenance activities. Required Action B.4.2.1 provides assurance that the required Sharpe Station gensets are available when a DG is out of service for greater than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. The availability of the required gensets are verified once per12 hours by locally monitoring various genset parameters.
The 7-day Completion Time of Required Action B.4.2.2 is a risk-informed allowed outage time (AOT) based on a plant-specific risk analysis. The Completion Time was established on the assumption that it would be used only for voluntary planned maintenance, inspections and testing. Use of Required Actions B.4.2.1 and B.4.2.2 are limited to once within an operating cycle (18 months) for each DG. Administrative controls applied during use of Required Action B.4.2.2 for voluntary planned maintenance activities ensure or require that (Ref. 16):
- a.
Weather conditions are conducive to an extended DG Completion Time. The extended DG Completion Time applies during the period of September 7 through April 5.
Attachment III to ET 22-0005 Page 12 of 18
AC Sources - Operating B 3.8.1 Wolf Creek - Unit 1 B 3.8.1-12 Revision 75 BASES ACTIONS B.4.1, B.4.2.1, and B4.2.2 (continued)
- b.
The offsite power supply and switchyard condition are conducive to an extended DG Completion Time, which includes ensuring that switchyard access is restricted and no elective maintenance within the switchyard is performed that would challenge offsite power availability. Elective maintenance or testing that would challenge offsite power availability is that activity that could result in an electrical power distribution system (offsite circuit or transmission network) transient or make the offsite circuit(s) unavailable or inoperable (Reference 19). The operational risk assessment procedure provides a list of equipment that could challenge offsite power availability.
- c.
Prior to relying on the required Sharpe Station gensets, the gensets are started and proper operation verified (i.e., the gensets reach rated speed and voltage). The Sharpe Station is not required to be operating the duration of the allowed outage time of the DG, however, a minimum of 8 gensets must be capable of providing power to a dead bus (station blackout conditions) to power 1 ESF train. Within 8 months prior to utilization of Required Action B.4.2.2, a load capability test/verification will be performed on the Sharpe Station gensets. The load capability testing/verification will consist of either 1) crediting a running of the gensets for load for commercial reasons for greater than 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />, or
- 2) tested by loading of the gensets for greater than 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> to a load equal to or greater than required to supply safety related loads in the event of a station blackout.
- d.
No equipment or systems assumed to be available for supporting the extended DG Completion Time are removed from service. The equipment or systems assumed to be available (including required support systems, i.e., associated room coolers, etc.) are as follows:
Auxiliary Feedwater System (three trains)
Component Cooling Water System (both trains and all four pumps)
Essential Service Water System (both trains)
Emergency Core Cooling System (two trains).
If, while Required Action B.4.2.2 is being used, one (or more) of the above systems or components is determined or discovered to be inoperable, or if Attachment III to ET 22-0005 Page 13 of 18
AC Sources - Operating B 3.8.1 Wolf Creek - Unit 1 B 3.8.1-13 Revision 47 BASES ACTIONS B.4.1, B.4.2.1, and B4.2.2 (continued) an emergent condition affecting DG OPERABILITY is identified, re-entry into Required Action B.2 and B.3 would be required, as applicable. In addition, the effect on plant risk would be assessed and any additional or compensatory actions taken, in accordance with the plants program for implementation of 10 CFR 50.65(a)(4). The 7-day Completion Time would remain in effect for the DG if Required Action B.2 and B.3 are satisfied.
The second Completion Time specified in Required Action B.4.2.2 establishes a limit on the maximum time allowed for any combination of required AC power sources to be inoperable during any single contiguous occurrence of failing to meet the LCO. If Condition B is entered while, for instance, an offsite circuit is inoperable, the LCO may already have been not met for up to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. If the offsite circuit is restored to OPERABLE status within the required 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, this could lead to a total of 10 days since initial failure to meet the LCO, to restore compliance with the LCO (i.e., restore the DG). At this time, an offsite circuit could again become inoperable and an additional 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> allowed prior to complete restoration of the LCO. The 10 day Completion Time provides a limit on time allowed in a specified condition after discovery of failure to meet the LCO. Although highly unlikely, this could occur indefinitely if not limited.
This limit is considered reasonable for situations in which Conditions A and B are entered concurrently. This limits the time the plant can alternate between Conditions A, B, and E (see Example 1.3-3).
Tracking the 10 day Completion Time is a requirement for beginning the Completion Time clock that is in addition to the normal Completion Time requirements. With respect to the 10 day Completion Time, the time zero is specified as beginning at the time LCO 3.8.1 was initially not met, instead of at the time Condition B was entered. This results in the requirement, when in this Condition, to track the time elapsed from both the Condition B time zero, and the time zero when LCO 3.8.1 was initially not met. Refer to Section 1.3, Completion Times, for a more detailed discussion of the purpose of the from discovery of failure to meet the LCO portion of the Completion Time.
C.1 If the availability of the required Sharpe Station gensets cannot be verified, the DG 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 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> Completion Time begins upon entry into Condition C.
However, the total time to restore an inoperable DG cannot exceed 7 days (per the Completion Time of Required Action B.4.2.2).
INSERT B 3.8.1-13 Attachment III to ET 22-0005 Page 14 of 18
INSERT B 3.8.1-13 If the required SBO DGs are or becomes unavailable with an inoperable DG, then action is required to restore the DG to OPERABLE status or restore the required SBO DGs to available status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> from declaring the DG inoperable and Condition B entry. If the required SBO DGs unavailability occurs sometime after 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> from initial entry into Condition B, then the remaining time to restore the DG to OPERABLE status or restore the SBO DGs to available status is limited to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. However, the total time to restore an inoperable DG cannot exceed 14 days (per the Completion Time of Required Action B.5).
The 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> Completion Time only begins on discovery that an inoperable DG exists for 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> and a required SBO DG is unavailable.
The Completion Time of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> is consistent with Regulatory Guide 1.93 (Ref. 6). The 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> Completion Time takes into account the capacity and capability of the remaining AC sources, a reasonable time for repairs, and low probability of a DBA occurring during this period.
Attachment III to ET 22-0005 Page 15 of 18
AC Sources - Operating B 3.8.1 Wolf Creek - Unit 1 B 3.8.1-14 Revision 47 BASES ACTIONS C.1 (continued)
The Completion Time of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> is consistent with Regulatory Guide 1.93 (Ref. 6). The 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> Completion Time takes into account the capacity and capability of the remaining AC sources, a reasonable time for repairs, and low probability of a DBA occurring during this period.
D.1 and D.2 Required Action D.1, which applies when two offsite circuits are inoperable, is intended to provide assurance that an event with a coincident single failure will not result in a complete loss of redundant required features. These redundant required features are those that are assumed to function to mitigate an accident, coincident with a loss of offsite power, in the safety analyses, such as the Emergency Core Cooling System and Auxiliary Feedwater System. These redundant features do not include monitoring requirements, such as Post Accident Monitoring and Remote Shutdown. These features are powered from redundant AC safety trains. This includes motor driven auxiliary feedwater pumps and the turbine driven auxiliary feedwater pump which must be available for mitigation of a feedwater line break. Single train features, other than the turbine driven auxiliary feedwater pump, are not included in this Condition. The Completion Time for this failure of redundant required features is reduced to 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> from that allowed for one train without offsite power (Required Action A.2). The rationale for the reduction to 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> is that Regulatory Guide 1.93 (Ref. 6) allows a Completion Time of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> for two required offsite circuits inoperable, based upon the assumption that two complete safety trains are OPERABLE. When a concurrent redundant required feature failure exists, this assumption is not the case, and a shorter Completion Time of 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> is appropriate. A Note is added to this Required Action stating that in MODES 1, 2, and 3, the turbine driven auxiliary feedwater pump is considered a required redundant feature. The reason for the Note is to confirm the OPERABILITY of the turbine driven auxiliary feedwater pump in this Condition, since the remaining OPERABLE motor driven auxiliary feedwater pump is not by itself capable of providing 100% of the auxiliary feedwater flow assumed in the safety analysis.
The Completion Time for Required Action D.1 is intended to allow the operator time to evaluate and repair any discovered inoperabilities. This Completion Time also allows for an exception to the normal "time zero" for beginning the allowed outage time "clock." In this Required Action the Completion Time only begins on discovery that both:
- a.
All required offsite circuits are inoperable; and
- b.
A required feature is inoperable and not in the safeguards position.
Attachment III to ET 22-0005 Page 16 of 18
AC Sources - Operating B 3.8.1 Wolf Creek - Unit 1 B 3.8.1-17 Revision 26 BASES ACTIONS F.1 (continued)
According to Reference 6, with both DGs inoperable, operation may continue for a period that should not exceed 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />.
G.1 and G.2 Required Action G.1 provides assurance that the appropriate Action is entered for the affected DG and offsite circuit if its associated LSELS becomes inoperable. An LSELS failure results in the inability of the EDG to start upon a loss of ESF bus voltage or degraded voltage condition.
Additionally, LSELS trips the ESF bus normal and alternate feeder supplies and trips non-essential loads. A sequencer failure results in the inability to start all or part of the safety loads powered from the associated ESF bus and thus when an LSELS is inoperable it is appropriate to immediately enter the Conditions for an inoperable DG and offsite circuit.
Because an inoperable LSELS affects all or part of the safety loads, an immediate Completion Time is appropriate.
The LSELS is an essential support system to both the offsite circuit and the DG associated with a given ESF bus. Furthermore, the sequencer is on the primary success path for most major AC electrically powered safety systems powered from the associated ESF bus. Therefore, loss of an ESF bus sequencer affects every major ESF system in the division. The 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> Completion Time of Required Action G.2 provides a period of time to correct the problem commensurate with the importance of maintaining sequencer OPERABILITY. This time period also ensures that the probability of an accident (requiring sequencer OPERABILITY) occurring during periods when the sequencer is inoperable is minimal.
H.1 and H.2 If the inoperable AC electric power sources or the load shedder and emergency load sequencer cannot be restored to OPERABLE status within the required Completion Time, or Required Actions B.1, B.2, B.3.1, B.3.2, B.4.1 or B.4.2 2 cannot be met within the required Completion Times, the unit must be brought to a MODE in which the LCO does not apply. To achieve this status, the unit must be brought to at least MODE 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and to MODE 5 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. The allowed Completion Times are reasonable, based on operating experience, to reach the required unit conditions from full power conditions in an orderly manner and without challenging plant systems.
B.3, B.4.1, B.4.2, and B.5 Attachment III to ET 22-0005 Page 17 of 18
AC Sources - Operating B 3.8.1 Wolf Creek - Unit 1 B 3.8.1-34 Revision 74 BASES REFERENCES
- 11.
ANSI C84.1-1982 (continued)
- 13.
Configuration Change Package (CCP) 08052, Revision 1, April 23, 1999.
- 14.
Amendment No. 161, April 21, 2005.
- 15.
Not used.
- 16.
Amendment No. 163, April 26, 2006.
- 17.
Amendment No. 154, August 4, 2004.
- 18.
Amendment No. 8, May 29, 1987.
- 19.
Condition Report 15727.
Not used.
Attachment III to ET 22-0005 Page 18 of 18