View source for CNL-22-043, Response to Request for Additional Information and Confirmation of Information Regarding Application to Modify Watts Bar Nuclear Plant Units 1 and 2 Technical Specification 3.7.8 to Support Shutdown Board.

{{Adams
| number = ML22122A248
| issue date = 05/02/2022
| title = Response to Request for Additional Information and Confirmation of Information Regarding Application to Modify Watts Bar Nuclear Plant Units 1 and 2 Technical Specification 3.7.8 to Support Shutdown Board.
| author name = Barstow J
| author affiliation = Tennessee Valley Authority
| addressee name = 
| addressee affiliation = NRC/Document Control Desk, NRC/NRR
| docket = 05000390, 05000391
| license number = NPF-090, NPF-096
| contact person = 
| case reference number = CNL-22-043, EPID L-2021-LLA-0174
| document type = Letter type:CNL, Response to Request for Additional Information (RAI)
| page count = 48
| project = EPID:L-2021-LLA-0174
| stage = Response to RAI
}}

=Text=
{{#Wiki_filter:1101 Market Street, Chattanooga, Tennessee 37402 CNL-22-043 May 2, 2022 10 CFR 50.90 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Watts Bar Nuclear Plant, Units 1 and 2 Facility Operating License Nos. NPF-90 and NPF-96 NRC Docket Nos. 50-390 and 391

==Subject:==
Response to Request for Additional Information and Confirmation of Information Regarding Application to Modify Watts Bar Nuclear Plant Units 1 and 2 Technical Specification 3.7.8 to Support Shutdown Board Cleaning (WBN-TS-19-019) (EPID L-2021-LLA-0174)

==References:==
: 1. TVA letter to NRC, CNL-21-062, Application to Modify Watts Bar Nuclear Plant Units 1 and 2 Technical Specification 3.7.8 to Support Shutdown Board Cleaning (WBN-TS-19-019), dated September 29, 2021 (ML21273A046)
: 2. NRC electronic mail to TVA, Request for Additional Information and Confirmation of Information Related to TVA's Request for Changes to Watts Bar Nuclear Plant, Units 1 and 2, Technical Specification 3.7.8 (EPID L-2021-LLA-0174), dated March 24, 2022 (ML22083A237)
In Reference 1, Tennessee Valley Authority (TVA) submitted a request for an amendment to Facility Operating License Nos. NPF-90 and NPF-96 for the Watts Bar Nuclear Plant (WBN), Units 1 and 2, respectively. The proposed amendment revises WBN Units 1 and 2 Technical Specification (TS) 3.7.8 to support future maintenance on the WBN Units 1 and 2 Shutdown Boards and associated 480 Volt boards and motor control centers on a permanent basis.
In Reference 2, the Nuclear Regulatory Commission (NRC) issued a request for additional information (RAI) and request for confirmation of information (RCI) and requested TVA respond by May 2, 2022.
The enclosure to this submittal provides the TVA response to the RAI and RCI. As noted in the enclosure, the TVA response to STSB RCI-1 requires a change to the proposed TS changes in Reference 1. Accordingly, Attachment 1 to the enclosure provides the existing WBN Units 1 and 2 TS pages marked-up to show the revised proposed change. to the enclosure provides the existing WBN Units 1 and 2 TS page retyped to

U.S. Nuclear Regulatory Commission CNL-22-043 Page 2 May 2, 2022 show the revised proposed change. There are no changes to the WBN Units 1 and 2 TS Bases provided in Reference 1. The TS changes in Attachments 1 and 2 to the enclosure supersede those provided in Reference 1. Attachment 3 to the enclosure provides further information in response to RAIs SCPB RAI-1 and SCPB RAI-2.
This letter does not change the no significant hazard considerations or the environmental considerations contained in Reference 1. Additionally, in accordance with 10 CFR 50.91(b)(1), TVA is sending a copy of this letter and the enclosure to the Tennessee Department of Environment and Conservation.
There are no new regulatory commitments associated with this submittal. Please address any questions regarding this request to Stuart L. Rymer, Senior Manager, Fleet Licensing, at slrymer@tva.gov.
I declare under penalty of perjury that the foregoing is true and correct. Executed on the 2nd day of May 2022.
Respectfully, Digitally signed by Rearden, Pamela S Date: 2022.05.02 13:57:58 -04'00' James Barstow Vice President, Nuclear Regulatory Affairs & Support Services

==Enclosure:==
Response to Request for Additional Information and Confirmation of Information cc (Enclosure):
NRC Regional Administrator - Region II NRC Senior Resident Inspector - Watts Bar Nuclear Plant NRC Project Manager - Watts Bar Nuclear Plant Director, Division of Radiological Health - Tennessee State Department of Environment and Conservation

Enclosure Response to Request for Additional Information and Confirmation of Information NRC Introduction By {{letter dated|date=September 29, 2021|text=letter dated September 29, 2021}} (Agencywide Documents Access and Management System (ADAMS) Accession No. ML21273A046), the Tennessee Valley Authority (TVA) submitted a license amendment request (LAR) to the U.S. Nuclear Regulatory Commission (NRC) for the Watts Bar Nuclear Plant (Watts Bar), Units 1 and 2. The proposed amendments would revise Watts Bar, Unit 1 and 2, Technical Specification (TS) 3.7.8, Essential Raw Cooling Water (ERCW) System, by adding a new Condition A to Watts Bar, Unit 1, TS 3.7.8, to permanently extend the allowed Completion Time to restore one ERCW system train to operable status from 72 hours to 7 days, to support maintenance on the Watts Bar, Unit 2, 6.9 kilovolt shutdown boards. The proposed amendments would also revise the bounding temperature for the ultimate heat sink (UHS) in Condition A to less than or equal to 78 degrees Fahrenheit. Additionally, the proposed amendments would add and/or revise the Note, numbering, and wording of the Conditions to specify when the Conditions apply.
Regulatory Bases:
General Design Criterion (GDC) 44, Cooling Water, requires, in part, that the system safety function shall be to transfer heat loads to the ultimate heat sink under normal and accident conditions, and that suitable redundancy in components shall be provided to assure that the system safety function can be accomplished, assuming a single failure.
Section 4.1 of the Enclosure to the LAR indicates that the ERCW system is designed to comply with GDC 44. Sections 3.2.4, 3.2.5, and 3.2.6 of the Enclosure to the LAR provide TVAs thermal and hydraulic analyses to demonstrate that the operation of the ERCW system under the proposed LAR conditions (e.g., revised UHS temperature limit, reduced number of operable ERCW pumps and EDGs, and one unit defueled) will be able to maintain its GDC 44 capabilities to perform its safety function of adequate component cooling capability for a design basis accident under the most limiting single failure.
SCPB RAI-1 In TVAs thermal analyses, Table 8 and Table 9 of the Enclosure to the LAR listed the following design parameters to compare against calculated values to show the margin of the heat removal capability (left column).
Parameter                      Design Minimum            Design Maximum (Current LAR)            (Previous LAR)
Btu/hr                   Btu/hr A/B Train - Component Cooling System        88,764,506                106,183,506 (CCS) Heat Exchanger (HX) Duty Residual Heat Removal HX Duty               54,800,000                54,800,000 Spent Fuel Pool HX Duty                     32,420,000                32,420,000 Core Spray System (CSS) HX Duty             87,323,731                81,294,921 The design of the ERCW in the proposed LAR has not been changed since the previous LAR for a similar analysis (ADAMS Accession No. ML19038A483). However, the NRC staff noted that the design values for the CCS HX Duty and CSS HX Duty in the proposed LAR are inconsistent with those data used in the previous LAR (right column, see Table 5 of CNL-22-043                                   E1 of 5

Enclosure ). For example, the design value (minimum) for the CSS HX duty for the current LAR is higher than the design value (maximum) for the CSS HX duty for the previous LAR.
Also, the design values (minimum and maximum) for the RHR HX duty and spent fuel pool HX duty are the same.
Provide the following:
: a.      Explain the above apparent inconsistences
: b.      Clarify which values (minimum or maximum) should be used for the determination of the margin of the heat removal capability and revise accordingly, if needed, and
: c.      Identify the source of the design data used for the current LAR.
TVA Response
: a. The change from maximum in the current LAR (Reference 1) to minimum in the previous LAR (Reference 2) was a change in terminology only.
The previous LAR used design maximum to signify the maximum duty of each HX during accident conditions. However, comparisons between predicted capability of the HX to remove heat and the required duty should show predicted capability greater than the required duty. Therefore; utilizing design minimum, signifying the minimum heat removal requirement of the HX during an accident, is the more appropriate terminology.
The two uses are functionally equivalent; the maximum HX duty listed in Table 5 of the previous LAR is equivalent to the minimum heat removal requirement listed in Tables 8 and 9 of the current LAR.
Changes in values from the previous LAR are explained in the response to SCPB RAI-2.
: b. See response in Part a of this RAI response.
: c. The following table identifies the source of the design data used for the current LAR.
Parameter                             Source of Required Duty Design Data CCS HX Duty          Tables 13A and 31 for the limiting accident case of the CCS Load List calculation.
See Attachment 3 to this enclosure for an explanation of the differing values from the current LAR and the previous LAR.
Residual Heat        Tables 13A and 31 for the limiting accident case of the CCS Load List Removal (RHR)        calculation.
HX Duty Spent Fuel Pool      100-hour full core offload maximum from the Alternate SFP Decay Heat (SFP) HX Duty        calculation.
CSS HX Duty          Appendix B of the calculation that evaluates the CSS Heat Exchangers for a decrease in ERCW Flow Rate.
See Attachment 3 of this enclosure for an explanation of the differing values from the current LAR (Reference 1) and the previous LAR (Reference 2).
CNL-22-043                                     E2 of 5

Enclosure SCPB RAI-2 Section 3.2.4 of the Enclosure to the LAR describes the thermal hydraulic evaluation method developed by TVA to support its request to extend the completion time for restoring one train of ERCW to operable status and to increase the UHS temperature. The methodology of the current analysis is similar to the one developed for the previous LAR (ADAMS Accession No. ML19038A483). Section 3.2.7 of both LARs (current and previous) list the analysis assumptions and conservatisms used in the respective analysis. In addition to the differences as identified in SCPB RAI-1 above, the NRC staff noted some differences in the assumptions and conservatisms. For example, in the current LAR, the flow values determined in the ERCW hydraulic analysis are reduced by 5 percent, whereas in the previous analysis, the flow values were reduced by 10 percent. Also, for the CSS HX model (LAR Section 3.2.6.1), the benchmarked PROTO-HX model for the LOCA analysis assumed 10 percent of the tubes were plugged, whereas in the previous LAR model, 5 percent of the tubes were assumed to be plugged (LAR Section 3.2.5.1).
: a.       Confirm or clarify whether the methodology developed for the proposed LAR is the same as, or different from, the methodology developed for the previous LAR.
: b.       Identify all the differences (including, but not limited to the above examples) in the assumptions, methodology, and acceptance criteria.
: c.       Provide the reasons for any differences.
TVA Response
: a.       The methodology for the proposed LAR (Reference 1) is the same as the methodology developed for the previous LAR (Reference 2) except for the differences detailed in Attachment 3 to this enclosure.
: b.       The differences in the assumptions, methodology, and acceptance criteria are described in the response in Attachment 3 to this enclosure regarding Methodology, Assumptions, and Design Input differences.
: c.       The requested information is described in Attachment 3 to this enclosure.
STSB RCI-1 Regulatory Basis:
Pursuant to 10 CFR 50.36, TSs for operating reactors are required, in part, to include items in the following five specific categories: (1) safety limits, limiting safety system settings, and limiting control settings; (2) limiting conditions for operation; (3) surveillance requirements; (4) design features; and (5) administrative controls.
Issue:
The proposed Condition C states: Required Action and associated Completion Time of Condition A not met.
Proposed Required Action A.2 states Verify UHS temperature is  78&deg; F with a Completion Time of 1 hour.
CNL-22-043                                     E3 of 5

Enclosure Required Action A.1 and A.2 are joined by the logical connector AND. As the proposed TS is currently constructed, if while in Condition A the temperature were to exceed 78&deg; F, Required Action A.2 would not be met, and Condition C would be entered. Therefore, the purpose of the second part of the Completion Time for Required Action A.1 it is not clear to the NRC staff .
Request:
Confirm that this is the intent of the proposed TS.
TVA Response The proposed change to Condition C of WBN Units 1 and 2 TS 3.7.8 in the Reference 1 LAR was in error. TVA is revising Condition C of Watts Bar Nuclear Plant (WBN), Units 1 and 2 TS 3.7.8 from Required Action and associated Completion Time of Condition A not met. to Required Action A.1 and associated Completion Time not met." Attachment 1 to this enclosure provides the existing WBN Units 1 and 2 TS pages marked-up to show the revised proposed change. Attachment 2 to this enclosure provides the existing WBN Units 1 and 2 TS page retyped to show the revised proposed change. There are no changes to the WBN Unit 1 and Unit 2 TS Bases provided in Reference 1. The TS changes in Attachments 1 and 2 to the enclosure supersede those provided in Reference 1.
In the Reference 3 safety evaluation (SE), WBN Unit 2 TS 3.7.8, Condition C was revised to state Required Action A.1 and associated Completion Time not met." However, in Reference 1, TVA stated:
WBN Unit 2 TS 3.7.8, Condition C is revised to change Required Action A.1 and associated Completion Time not met, to Required Action and associated Completion Time of Condition A not met. This is an administrative change to reflect that Condition C applies to both Required Actions A.1 and A.2.
A similar change was also made to WBN Unit 1 TS 3.7.8, Condition C. If Action A.2 of WBN Units 1 and 2 TS 3.7.8 (i.e., verify UHS temperature is less than or equal to 78&deg;Fahrenheit (F) within one hour and once every 12 hours thereafter) is not met then the affected unit enters Action A.1 of WBN Units 1 and 2 TS 3.7.8, which requires restoration of an ERCW train to Operable status within seven days and 24 hours from discovery of Condition A entry greater than or equal to 48 hours concurrent with UHS temperature greater than 78&deg;F. This logic is consistent with Section 2.3 of Reference 1, which states:
If UHS temperature exceeds 78&#xba;F after 48 hours of continuous ERCW train inoperability, then the specified conditions for crediting the availability of the inoperable ERCW train are no longer met and action must be taken to restore the ERCW train to an operable status within 24 hours. Otherwise, the unit must enter WBN Unit 2 TS 3.7.8, Condition C, which requires the unit to be in Mode 3 within six hours and Mode 5 within 36 hours. If UHS temperature is discovered to be > 78&#xba; F, prior to 48 hours of continuous operation in Condition A, then the 24-hour Completion Time to restore the inoperable ERCW train to operable status starts after 48 hours of continuous operation in Condition A. However, the proposed change to WBN Unit 2 TS 3.7.8 does not allow continued operation in Condition A for greater than seven days.
CNL-22-043                                   E4 of 5

Enclosure As noted in Reference 4, the above logic is similar to WBN Units 1 and 2 TS 3.8.1, Condition B for the extended allowed outage time allowed for an inoperable diesel generator that also relies on the availability of a compensatory measure. Specifically.
the Completion Time for WBN Units 1 and 2 TS 3.8.1, Required Action B.5 allows 72 hours from discovery of unavailability of 6.9 kV FLEX DG AND 24 hours from discovery of Condition B entry  48 hours concurrent with unavailability of 6.9 kV FLEX DG.
References
: 1. TVA letter to NRC, CNL-21-062, Application to Modify Watts Bar Nuclear Plant Units 1 and 2 Technical Specification 3.7.8 to Support Shutdown Board Cleaning (WBN-TS-19-019), dated September 29, 2021 (ML21273A046)
: 2. TVA letter to NRC, CNL-19-014, Application to Modify Watts Bar Nuclear Plant Unit 2 Technical Specifications 3.7.8 to Extend the Completion Time for an Inoperable Essential Raw Cooling Water Train on a One-Time Basis (WBN-TS-18-07), dated February 7, 2019 (ML19038A483)
: 3. NRC letter to TVA, Watts Bar Nuclear Plant, Unit 2- Issuance of Amendment No. 35 Regarding One-Time Extension of Completion Time for Technical Specification 3.7.8 for Inoperable Essential Raw Cooling Water Train (EPID L-2019-LLA-0020), dated February 24, 2020 (ML20024F835)
: 4. TVA letter to NRC, CNL-19-124, Response to Request for Additional Information to Application to Modify Watts Bar Nuclear Plant Unit 2 Technical Specifications 3.7.8 to Extend the Completion Time for an Inoperable Essential Raw Cooling Water Train on a One-Time Basis (WBN-TS-18-07) (EPID L-2019-LLA-0020), dated January 13, 2020 (ML20014D230)
CNL-22-043                                   E5 of 5

Enclosure Attachment 1 Revised Proposed TS Changes (Markups) for WBN Units 1 and 2 CNL-22-043

ERCW 3.7.8 3.7 PLANT SYSTEMS 3.7.8 Essential Raw Cooling Water (ERCW) System LCO 3.7.8                       Two ERCW trains shall be OPERABLE.
APPLICABILITY:                  MODES 1, 2, 3, and 4.
ACTIONS CONDITION                             REQUIRED ACTION                          COMPLETION TIME
 ------------------NOTES-------------------      A.1  ------------------NOTES------------
: 1. Only applicable when Unit 2 is                    1.         Enter applicable defueled.                                                  Conditions and Required Actions of
: 2. Only applicable during planned                               LCO 3.8.1, "AC maintenance of a Unit 2 6.9kV                              Sources- Operating,"
shutdown board and the                                     for diesel generator associated 480V boards and                                 made inoperable by motor control centers.                                     ERCW.
: 2.         Enter applicable A.          One ERCW train                                      Conditions and inoperable.                                         Required Actions of LCO 3.4.6, "RCS Loops-MODE 4," for residual heat removal loops made inoperable by ERCW.
Restore ERCW train to                    7 days OPERABLE status.
AND 24 hours from discovery of Condition A entry 48 hours concurrent with UHS AND                                           temperature > 78&deg;F.
(continued)
Watts Bar-Unit 1                                       3.7-19                                         Amendment 69,

ERCW 3.7.8 ACTIONS (continued)
CONDITION                       REQUIRED ACTION                            COMPLETION TIME A. (continued)                       A.2  Verify UHS temperature is                   1 hour 78&deg;F.
AND Once every 12 hours thereafter.
AB.      One ERCW train              AB.1  ------------------NOTES------------
inoperable for reasons            1.         Enter applicable other than Condition A,                      Conditions and other than for Condition C.                  Required Actions of LCO 3.8.1, "AC Sources- Operating,"
for emergency diesel generator made inoperable by ERCW.
: 2.         Enter applicable Conditions and Required Actions of LCO 3.4.6, "RCS Loops-MODE 4," for residual heat removal loops made inoperable by ERCW.
Restore ERCW train                          72 hours OPERABLE status.
BC. Required Action A.1 and       BC.1  Be in MODE 3.                              6 hours associated Completion Time not met.                 AND OR                            BC.2  Be in MODE 5.                              36 hours Required Action and associated Completion Time of Condition B not met.
Watts Bar-Unit 1                             3.7-20                                  Amendment 69, 132, 135,

ERCW 3.7.8 SURVEILLANCE REQUIREMENTS SURVEILLANCE                                                   FREQUENCY SR 3.7.8.1       -----------------------------NOTE-----------------------------
Isolation of ERCW flow to individual components does not render the ERCW inoperable.
Verify each ERCW manual, power operated, and                      In accordance with automatic valve in the flow path servicing safety                 the Surveillance related equipment, that is not locked, sealed, or                 Frequency Control otherwise secured in position, is in the correct                  Program position.
SR 3.7.8.2        Verify each ERCW automatic valve in the flow path                 In accordance with that is not locked, sealed, or otherwise secured in               the Surveillance position, actuates to the correct position on an actual           Frequency Control or simulated actuation signal.                                    Program SR 3.7.8.3        Verify each ERCW pump starts automatically on an                  In accordance with actual or simulated actuation signal.                             the Surveillance Frequency Control Program Watts Bar-Unit 1                                 3.7-20a                                   Amendment132,

ERCW 3.7.8 3.7 PLANT SYSTEMS 3.7.8 Essential Raw Cooling Water (ERCW) System LCO 3.7.8                   Two ERCW trains shall be OPERABLE.
APPLICABILITY:              MODES 1, 2, 3, and 4.
ACTIONS CONDITION                         REQUIRED ACTION                        COMPLETION TIME
 ----------------NOTES----------------      A.1    ------------NOTES-----------
: 1. Only applicable during the                     1. Enter applicable Unit 1 spring 2020 outage                         Conditions and (U1R16), but no later than                        Required Actions of May 31, 2020.                                     LCO 3.8.1, "AC
: 2. Only applicable when Unit                           Sources - Operating,"
1 is defueled.                                    for diesel generator made inoperable by ERCW.
: 32. Only applicable during planned maintenance of a                     2. Enter applicable Unit 1 n 6.9 kV shutdown                          Conditions and board and the           1 A-A                     Required Actions of and associated 480 V                              LCO 3.4.6, "RCS boards and motor control                          Loops - MODE 4," for centers.                                          residual heat removal
 ------------------------------------------             loops made inoperable by ERCW.
A. One ERCW train                                 ----------------------------------
inoperable.
Restore ERCW train to              7 days OPERABLE status.
AND 24 hours from discovery of Condition A entry 48 hours concurrent with UHS temperature > 718 &deg;F AND (continued)
Watts Bar - Unit 2                                3.7-18                                   Amendment 35,

ERCW 3.7.8 ACTIONS (continued)
CONDITION                REQUIRED ACTION                       COMPLETION TIME A.   (continued)              A.2   Verify UHS temperature             1 hour is  718&deg; F.
AND Once every 12 hours thereafter B. One ERCW train           B.1   -----------NOTES-------------
inoperable for reasons         1. Enter applicable other than Condition A.            Conditions and Required Actions of LCO 3.8.1, "AC Sources- Operating,"
for diesel generator made inoperable by ERCW.
: 2. Enter applicable Conditions and Required Actions of LCO 3.4.6, "RCS Loops-MODE 4," for residual heat removal loops made inoperable by ERCW.
Restore ERCW train to              72 hours OEPRABLE status.
C. Required Action A.1 and    C.1   Be in MODE 3.                      6 hours associated Completion Time not met.                   AND OR                         C.2   Be in MODE 5.                      36 hours Required Action and associated Completion Time of Condition B not met.
Watts Bar - Unit 2                 3.7-18a                                   Amendment 35,

Enclosure Attachment 2 Revised Proposed TS Change (Final Typed) for WBN Units 1 and 2 CNL-22-043

ERCW 3.7.8 3.7 PLANT SYSTEMS 3.7.8 Essential Raw Cooling Water (ERCW) System LCO 3.7.8                       Two ERCW trains shall be OPERABLE.
APPLICABILITY:                  MODES 1, 2, 3, and 4.
ACTIONS CONDITION                             REQUIRED ACTION                          COMPLETION TIME
 ------------------NOTES-------------------      A.1  ------------------NOTES------------
: 1. Only applicable when Unit 2 is                    1.         Enter applicable defueled.                                                  Conditions and Required Actions of
: 2. Only applicable during planned                               LCO 3.8.1, "AC maintenance of a Unit 2 6.9kV                              Sources- Operating,"
shutdown board and the                                     for diesel generator associated 480V boards and                                 made inoperable by motor control centers.                                     ERCW.
: 2.         Enter applicable A.          One ERCW train                                      Conditions and inoperable.                                         Required Actions of LCO 3.4.6, "RCS Loops-MODE 4," for residual heat removal loops made inoperable by ERCW.
Restore ERCW train to                    7 days OPERABLE status.
AND 24 hours from discovery of Condition A entry 48 hours concurrent with UHS AND                                           temperature > 78&deg;F.
(continued)
Watts Bar-Unit 1                                       3.7-19                                         Amendment 69,

ERCW 3.7.8 ACTIONS (continued)
CONDITION                  REQUIRED ACTION                            COMPLETION TIME A. (continued)                   A.2 Verify UHS temperature is                   1 hour 78&deg;F.
AND Once every 12 hours thereafter.
B.       One ERCW train          B.1  ------------------NOTES------------
inoperable for reasons       1.         Enter applicable other than Condition A.                 Conditions and Required Actions of LCO 3.8.1, "AC Sources- Operating,"
for emergency diesel generator made inoperable by ERCW.
: 2.         Enter applicable Conditions and Required Actions of LCO 3.4.6, "RCS Loops-MODE 4," for residual heat removal loops made inoperable by ERCW.
Restore ERCW train                          72 hours OPERABLE status.
C.       Required Action A.1 and C.1  Be in MODE 3.                              6 hours associated Completion Time not met.           AND OR                      C.2  Be in MODE 5.                              36 hours Required Action and associated Completion Time of Condition B not met.
Watts Bar-Unit 1                        3.7-20                                  Amendment 69, 132, 135,

ERCW 3.7.8 SURVEILLANCE REQUIREMENTS SURVEILLANCE                                                   FREQUENCY SR 3.7.8.1       -----------------------------NOTE-----------------------------
Isolation of ERCW flow to individual components does not render the ERCW inoperable.
Verify each ERCW manual, power operated, and                      In accordance with automatic valve in the flow path servicing safety                 the Surveillance related equipment, that is not locked, sealed, or                 Frequency Control otherwise secured in position, is in the correct                  Program position.
SR 3.7.8.2        Verify each ERCW automatic valve in the flow path                 In accordance with that is not locked, sealed, or otherwise secured in               the Surveillance position, actuates to the correct position on an actual           Frequency Control or simulated actuation signal.                                    Program SR 3.7.8.3        Verify each ERCW pump starts automatically on an                  In accordance with actual or simulated actuation signal.                             the Surveillance Frequency Control Program Watts Bar-Unit 1                                 3.7-20a                                   Amendment132,

ERCW 3.7.8 3.7 PLANT SYSTEMS 3.7.8 Essential Raw Cooling Water (ERCW) System LCO 3.7.8                   Two ERCW trains shall be OPERABLE.
APPLICABILITY:              MODES 1, 2, 3, and 4.
ACTIONS CONDITION                         REQUIRED ACTION                        COMPLETION TIME
 ----------------NOTES----------------      A.1    ------------NOTES-----------
: 1. Only applicable when Unit 1                    1. Enter applicable is defueled.                                      Conditions and Required Actions of
: 2. Only applicable during                              LCO 3.8.1, "AC planned maintenance of a                          Sources - Operating,"
Unit 1 6.9 kV shutdown                            for diesel generator made inoperable by board and the associated ERCW.
480 V boards and motor control centers.                             2. Enter applicable
 ------------------------------------------             Conditions and Required Actions of A. One ERCW train                                      LCO 3.4.6, "RCS inoperable.                                       Loops - MODE 4," for residual heat removal loops made inoperable by ERCW.
Restore ERCW train to              7 days OPERABLE status.
AND 24 hours from discovery of Condition A entry 48 hours concurrent with UHS temperature > 78 &deg;F AND (continued)
Watts Bar - Unit 2                                3.7-18                                   Amendment 35,

ERCW 3.7.8 ACTIONS (continued)
CONDITION                REQUIRED ACTION                       COMPLETION TIME A.   (continued)              A.2   Verify UHS temperature             1 hour is  78&deg; F.
AND Once every 12 hours thereafter B. One ERCW train           B.1   -----------NOTES-------------
inoperable for reasons         1. Enter applicable other than Condition A.            Conditions and Required Actions of LCO 3.8.1, "AC Sources- Operating,"
for diesel generator made inoperable by ERCW.
: 2. Enter applicable Conditions and Required Actions of LCO 3.4.6, "RCS Loops-MODE 4," for residual heat removal loops made inoperable by ERCW.
Restore ERCW train to              72 hours OEPRABLE status.
C. Required Action A.1 and    C.1   Be in MODE 3.                      6 hours associated Completion Time not met.                   AND OR                         C.2   Be in MODE 5.                      36 hours Required Action and associated Completion Time of Condition B not met.
Watts Bar - Unit 2                 3.7-18a                                   Amendment 35,

Enclosure Attachment 3 Response to SCPB RAI-2 METHODOLOGY The methodology applied in the proposed license amendment request (LAR) (Reference 1) analysis is essentially the same as that applied in the previous LAR (Reference 2).
Assumptions and design inputs are compared in the table below and differences are explained. The significant differences are as follows.
: 1. The current LAR analysis credits the Essential Raw Cooling Water (ERCW) system modifications, which replaced and relocated the discharge valve from the component cooling system (CCS) heat exchanger (HX) C (0-FCV-67-152), cross-ties the CCS HX ERCW discharge header by opening existing valves, and rebalances ERCW header flow.
These alignment changes modify ERCW hydraulic performance.
: 2. Margins added to individual design inputs/outputs were removed or minimized to eliminate stacking of margins and provide a more realistic prediction of available ERCW cooling water flow rates and maximum allowable ERCW temperature. The most significant example is the reduction of the predicted ERCW flows by five percent (%)
rather than 10%, as was applied in the previous LAR analysis method. Other examples are provided in Tables 1 and 2.
Margin was removed to gain a larger range of acceptable ERCW temperatures for the permanent two-season LAR (note the resultant increase in acceptable maximum ultimate heat sink (UHS) temperature from 71&deg; F to 78&deg; F to support autumn river temperatures).
It was also considered that this approach allows a more accurate assessment of margin by design engineering and the regulator, since margin can be analyzed by examining only the conclusions of the analysis rather than considering both the conclusions and any subsidiary supporting margins.
: 3. The thermal performance calculations for each heat exchanger and heating, ventilation, and air conditioning (HVAC cooler were revised to incorporate curves of thermal performance as a function of ERCW flow rate and temperature rather than executing the models within the SDBD Cleaning calculation. This was done to incorporate station configuration changes and to ensure future revisions to these calculations are evaluated for impact to the LAR analysis. These analyses use the same methods and inputs as those in the previous LAR, with exceptions noted in the tables below.
References
: 1. TVA letter to NRC, CNL-21-062, Application to Modify Watts Bar Nuclear Plant Units 1 and 2 Technical Specification 3.7.8 to Support Shutdown Board Cleaning (WBN-TS-19-019), dated September 29, 2021 (ML21273A046)
: 2. TVA letter to NRC, CNL-19-014, Application to Modify Watts Bar Nuclear Plant Unit 2 Technical Specifications 3.7.8 to Extend the Completion Time for an Inoperable Essential Raw Cooling Water Train on a One-Time Basis (WBN-TS-18-07), dated February 7, 2019 (ML19038A483)
CNL-22-043                             Encl A3-1 of 29

Enclosure Attachment 3 Response to SCPB RAI-2 Table 1 Analysis Assumptions Previous LAR                              Current LAR                   Difference Basis 5.1  Minimum ERCW pump                    5.1 Minimum ERCW pump                    None performance is assumed by                performance is assumed by specifying a lower bounding head         specifying a lower bounding head versus flow curve relative to the        versus flow curve relative to the vendor pump curves.                      vendor pump curves.
Technical Justification: This            Technical Justification: This ensures that the actual ERCW             ensures that the actual ERCW flow rates supplied in this unlikely     flow rates supplied in this unlikely accident scenario will                   accident scenario will conservatively exceed the                conservatively exceed the analysis predicted flow rates.           analysis predicted flow rates.
CNL-22-043                                           Enc A3-2 of 29

Enclosure Attachment 3 Response to SCPB RAI-2 Table 1 Analysis Assumptions Previous LAR                           Current LAR                  Difference            Basis 5.2  The flow values determined in the 5.2 The flow values determined in the  Predicted ERCW flow  The additional ERCW hydraulic analysis are           ERCW hydraulic analysis are        rates are reduced by margin from the reduced by ten percent to account     reduced by five percent to account 5% instead of 10%    10% reduction is for the measurement and analysis      for analysis uncertainties.                             deemed overly uncertainties.                                                                                conservative Technical Justification: This                           considering the Technical Justification: This         reasonably bounds the                                   minimum ERCW reasonably bounds the                 uncertainties associated with                           pump performance uncertainties associated with         baseline model development and                          curve applied in baseline model development and        testing.                                                both analyses testing.                                                                                      under Assumption 5.1.
This allows the margin to be retained in the proposed technical specification (TS) temperature limit versus potentially narrowing the gap between the proposed limit and the actual UHS temperature expected during the spring and fall outages.
CNL-22-043                                        Enc A3-3 of 29

Enclosure Attachment 3 Response to SCPB RAI-2 Table 1 Analysis Assumptions Previous LAR                            Current LAR                   Difference       Basis 5.3  Maximum heat transfer to the        5.3 Maximum heat transfer to the         None CCS is assumed in order to              CCS is assumed in order to maximize the CCS heat                   maximize the CCS heat exchanger ERCW outlet                   exchanger ERCW outlet temperature. This is                    temperature. This is accomplished by specifying zero         accomplished by specifying zero fouling inside and outside of the       fouling inside and outside of the heat exchanger tubes and zero           heat exchanger tubes and zero plugged tubes in the respective         plugged tubes in the respective PROTO-HX models.                        PROTO-HX models.
Technical Justification: This           Technical Justification: This maximizes the ERCW heat load,           maximizes the ERCW heat load, which is conservative with respect      which is conservative with respect to the objective.                       to the objective.
5.4  The ERCW system B-train fails in    5.4 The emergency power train failure    None            Generalized to its entirety.                           is assumed to apply to both units                    dual-unit LAR.
such that no credit is taken for the Technical Justification: No             shutdown unit associated credit is taken for the Unit 1          equipment even though the B-train equipment even though the       shutdown unit diesel generator Unit 1 B-train diesel generator and     and SDBD are likely to be SDBD are likely to be available.        available.
This is a conservative assumption which maximizes the demand on           Technical Justification: This is the A-train of ERCW.                    a conservative assumption which maximizes the demand on the available train of ERCW.
CNL-22-043                                          Enc A3-4 of 29

Enclosure Attachment 3 Response to SCPB RAI-2 Table 1 Analysis Assumptions Previous LAR                            Current LAR                 Difference       Basis 5.5  The 1A-A 6.9kV Shutdown Board      5.5 The respective 6.9kV SDBD is not   None            Generalized to is not removed from service until      removed from service until the                     dual-unit LAR.
WBN Unit 1 is in a refueling           shutdown unit is in a refueling outage, with the fuel removed.         outage, with the fuel removed.
Technical Justification: This is       Technical Justification: This is stipulated as a limiting condition     stipulated as a limiting condition for operation in the subject LAR       for operation in the subject LAR system alignment.                      system alignment.
CNL-22-043                                         Enc A3-5 of 29

Enclosure Attachment 3 Response to SCPB RAI-2 Table 1 Analysis Assumptions Previous LAR                            Current LAR                     Difference         Basis 5.6  The spent fuel pool (SFP) heat     5.6 The SFP heat load is maximized        The previous LAR   The previous LAR load is maximized by assuming          by assuming that the full core        applied a CCS HX   value incorporated that the full core offload for the     offload for the refueling unit occurs duty acceptance    a beyond design refueling unit occurs at 100 hours     at 100 hours after shutdown. This     criterion of       basis SFP load of after shutdown. This is                is conservative because the           106,183,506 BTU/hr 50,215,000 conservative because the earliest      earliest time defueling can begin     versus the current BTU/hr deemed time defueling can begin per WBN       per TS 3.9.10 is 100 hours, and       LAR value of       overly Units 1 and 2 TS 3.9.10, Decay        the SDBD outage cannot begin          88,764,506 BTU/hr. conservative. The Time, is 100 hours, and the 1A-A      until the full core has been                             design basis SFP 6.9kV SDBD outage cannot begin         offloaded per the LAR. Therefore,                        heat load of until the full core has been           the outage on the 6.9kV SDBD                             32,420,000 offloaded per the LAR. Therefore,      selected for maintenance does not                        BTU/hr plus the the outage on the 1A-A 6.9kV           begin until the unit has been shut                       shutdown unit seal SDBD selected for maintenance          down for at least 100 hours.                             water HX duty of does not begin until WBN Unit 1                                                                 376,000 BTU/hr has been shut down for at least        Technical Justification: This is                         are applied in the 100 hours.                             stipulated as a limiting condition                       current LAR.
for operation in the subject LAR Technical Justification: This is       system alignment and is stipulated as a limiting condition     consistent with the TVA Alternate for operation in the subject LAR       SFP Decay Heat Analysis.
system alignment and is consistent with the TVA Alternate SFP Decay Heat Analysis.
CNL-22-043                                          Enc A3-6 of 29

Enclosure Attachment 3 Response to SCPB RAI-2 Table 1 Analysis Assumptions Previous LAR                              Current LAR                 Difference       Basis 5.7  It is assumed that all Unit 1,       5.7 It is assumed that all shutdown    None            Generalized to non-essential cooling loads are          unit, non-essential cooling loads                  dual-unit LAR.
isolated prior to and in preparation     supplied by the train in service for removal of the SDBD from             post loss of offsite service.                                 power (LOOP)/loss of train (LOT) are isolated prior to and in Technical Justification: This is         preparation for removal of the stipulated as a limiting condition       SDBD from service.
for operation in the subject LAR system alignment.                        Technical Justification: This is stipulated as a limiting condition for operation in the subject LAR system alignment.
CNL-22-043                                            Enc A3-7 of 29

Enclosure Attachment 3 Response to SCPB RAI-2 Table 1 Analysis Assumptions Previous LAR                             Current LAR                Difference              Basis 5.8  It is assumed that the SFP is        5.8 It is assumed that the SFP is      Loss of spent fuel    No credit was and  initially at the maximum normal          initially at the maximum           pool cooling and pool taken for SFP 5.9  temperature of 127 degrees               temperature of 159.24F.           heat-up from the      heat-up from Fahrenheit (F).                                                            maximum normal        127 F to 159.24 F Technical Justification: This      operation temperature in either analysis.
Technical Justification: This            temperature is consistent with the of 127F is not maximizes the heat load on the           maximum allowable SFP heat         postulated in the CCS and ERCW system and                  load which established this as the current analysis.
minimizes the time for SFP               design maximum SFP heat-up and approach to boiling.         temperature from the TVA Alternate SFP Decay Heat It is assumed that the SFP heats         Analysis.
up following initial loss of cooling to a temperature less than or equal to 159.24F.
Technical Justification: As the SFP temperature increases, the heat transfer to the CCS increases until the SFP decay load is matched. This temperature is the design maximum SFP temperature from the Tennessee Valley Authority (TVA) Alternate SFP Decay Heat Analysis.
CNL-22-043                                             Enc A3-8 of 29

Enclosure Attachment 3 Response to SCPB RAI-2 Table 1 Analysis Assumptions Previous LAR                             Current LAR                     Difference              Basis N/A  It is assumed that the ERCW         5.9 It is assumed that the ERCW           ERCW temperature       Provides a more water temperature is 85F for this      water temperature is 70 F for this   for hydraulic analysis conservative hydraulic analysis.                     hydraulic analysis.                   reduced by 15F.       prediction of delivered flow Technical Justification: The            Technical Justification: The                                 rates and is not base case models set this               base case models set this                                    applied in the heat temperature at the UHS maximum          temperature at the UHS maximum                               transfer analyses.
of 85F.                                of 85F. Specifying 70F for                                 This temperature this analysis conservatively                                 reduction accounts increases the water density                                  for a minor and hydraulic resistance,                                    increase in the consistent with expected results in                          hydraulic the 70F to 80F range.                                      resistance on the order of 0.2%.
5.10 For the 1A-A SDBD maintenance,      N/A N/A                                   None                   This assumption is it is assumed that SFP cooling will                                                                  specific to the be transferred from the A SFP HX                                                                     1A-A SDBD to the B SFP HX.                                                                                     cleaning scenario.
(Similar alignments are                                      However, this is Technical Justification: For this       implemented for each SDBD                                    generalized to the scenario, only one CCS pump             cleaning scenario as required and                            dual-unit LAR by supplying the Unit 2 A CCS train is     explained in detail in the analysis).                        evaluating similar available due to loss of the                                                                         alignments for redundant power supplies to the                                                                      each additional C-S CCS pump (LOT B and loss                                                                         case in the current of the 1A-A SDBD).                                                                                   LAR.
CNL-22-043                                           Enc A3-9 of 29

Enclosure Attachment 3 Response to SCPB RAI-2 Table 1 Analysis Assumptions Previous LAR                              Current LAR                    Difference               Basis 5.11 It is assumed that ERCW flow to      5.10 It is assumed that ERCW flow to      The current LAR         The current LAR the Auxiliary Feedwater (AFW) is          the AFW is isolated for this         assumption did not      analysis also isolated for this analysis.               analysis.                            specifically address    provides more the potential impact to than adequate Technical Justification: This is          Technical Justification: This is     AFW pump available      suction head for conservative, as the AFW pumps            conservative, as the AFW pumps       net positive suction    the AFW pumps take suction from the ERCW                take suction from the ERCW           head.                   based on the discharge headers. Flow to the            discharge headers. Flow to the                               discharge header AFW pumps would reduce the                AFW pumps would reduce the                                   flow rate and ERCW discharge flow and the               ERCW discharge flow and the                                  elevation relative backpressure in the discharge             backpressure in the discharge                                to the AFW pumps headers, resulting in higher              headers, resulting in higher                                 suction.
available flow rates to all users of      available flow rates to all users of ERCW. Also, the ERCW                      ERCW.
discharge header flow rate and elevation (730-6) relative to the AFW pump elevation (715-1) are such that more than adequate suction head and flow is available to supply the AFW pumps.
CNL-22-043                                             Enc A3-10 of 29

Enclosure Attachment 3 Response to SCPB RAI-2 Table 1 Analysis Assumptions Previous LAR                               Current LAR                  Difference Basis 5.12 The SFP heat load, for analysis      5.11 The SFP heat load, for analysis      None purposes, is conservatively               purposes, is conservatively assumed to be the design basis            assumed to be the design basis 100 hour full core offload                100 hour full core offload maximum of 32.42 MBtu/hr listed           maximum consistent with the in Table 7.2 of the Alternate SFP         predicted CCS temperature in Decay Heat Analysis. Because              Table 7.2 of the Alternate SFP the 1A-A 6.9 kV SDBD outage               Decay Heat Analysis. Because cannot begin, due to LAR                  the 6.9 kV SDBD outage cannot restrictions, until the full core begin, due to analysis restrictions, offload is complete, the actual fuel until the full core offload is pool total heat load will be less complete, the actual fuel pool total due to the additional time, not considered herein, and required to        heat load will be less due to the offload the core (approximately 40        additional time, not considered hours).                                   herein, and required to offload the core (approximately 40 hours).
Technical Justification: This is the SFP heat load used to establish           Technical Justification: This is the the design maximum pool                   SFP heat load used to establish temperature of 159.24 F. This             the design maximum pool heat load is applied as the               temperature of 159.24 F. This minimum acceptance criterion to           heat load is applied as the which the predicted SFP HX duty           minimum acceptance criterion to under the LAR conditions is               which the predicted SFP HX duty compared to demonstrate the               under the LAR conditions is available heat transfer margin. It        compared to demonstrate the is noted that actual conditions will      available heat transfer margin. It be utilized to determine the time to      is noted that actual conditions will begin WBN Unit 1 core offload             be utilized to determine the time to begin core offload and the rate at CNL-22-043                                             Enc A3-11 of 29

Enclosure Attachment 3 Response to SCPB RAI-2 Table 1 Analysis Assumptions Previous LAR                      Current LAR            Difference Basis and the rate at which the WBN     which the core can be off loaded, Unit 1 core can be off loaded, as as described in UFSAR Section described in WBN dual-unit Final  9.1.3.1.1.
Safety Analysis Report (UFSAR)
Section 9.1.3.1.
CNL-22-043                                   Enc A3-12 of 29

Enclosure Attachment 3 Response to SCPB RAI-2 Table 1 Analysis Assumptions Previous LAR                           Current LAR                  Difference Basis 5.13  The maximum residual heat         5.12 The maximum RHR HX duty            None removal (RHR) HX duty of               of 54,800,000 Btu/hr 54,80,000 Btu/hr (loss of cooling      (LOCA-RECIRC mode) and accident (LOCA)-RECIRC mode)           design CCS flowrate of 5000 gpm and design CCS flowrate of 5000        are assumed as listed in Table A.1 gallons per minute (gpm) are           of the CCS Load List calculation.
assumed as listed in Table A.1 of the CCS Load List calculation.         Technical Justification: This conservatively maximizes the load Technical Justification: This          on the CCS HX and maximizes conservatively maximizes the load      the ERCW cooling flow required.
on the CCS HX and maximizes            This heat load is applied as the the ERCW cooling flow required.        minimum acceptance criterion to This heat load is applied as the       which the predicted RHR duty minimum acceptance criterion to        under the LAR conditions is which the predicted RHR duty           compared to demonstrate the under the LAR conditions is            available heat transfer margin.
compared to demonstrate the available heat transfer margin.
CNL-22-043                                          Enc A3-13 of 29

Enclosure Attachment 3 Response to SCPB RAI-2 Table 1 Analysis Assumptions Previous LAR                                Current LAR               Difference       Basis 5.14 It is assumed that the non-seismic   5.13 It is assumed that the non-seismic None            Conservatively portion of the ERCW piping                portion of the ERCW piping                         generalized to supplying the station air                 supplying the station air                          dual-unit LAR.
compressors in the Turbine                compressors in the Turbine Building fails and discharges             Building fails and discharges ERCW flow through each 4-inch             ERCW flow through both 4-inch diameter pipe.                            diameter pipes.
Technical Justification: The low          Technical Justification: The low pressure and high flow control            pressure and high flow control system logic would normally               system logic would normally isolate valves 0-FCV-67-0205-A            isolate valves 0-FCV-67-0205-A and 0-FCV-67-0208-B. However,             and 0-FCV-67-0208-B.
for this scenario neither of these        The 67-0205-A valve is powered valves will be powered and will fail      from the 1A-A SDBD and the as-is. Assuming both valves wide          67 0208-B is powered from the open provides a conservative loss         1B-B SDBD. Therefore, neither of of ERCW flow in excess of the             these valves will be powered and 350 gpm flow switch setpoint.             will fail as-is for a scenario involving LOT A and 1B-B SDBD out of service (e.g., Case 2D1BB).
Assuming one or both valves wide open depending on the availability of the respective power source for each case in this analysis, provides a conservative loss of ERCW flow in excess of the 350 gpm flow switch setpoint.
CNL-22-043                                             Enc A3-14 of 29

Enclosure Attachment 3 Response to SCPB RAI-2 Table 1 Analysis Assumptions Previous LAR                            Current LAR                 Difference Basis 5.15 To account for unidentified system 5.14 To account for unidentified system None leakage, it is assumed that             leakage, it is assumed that 100 gpm of ERCW flow is                 100 gpm of ERCW flow is discharged directly from the            discharged directly from the system.                                 system.
Technical Justification: This           Technical Justification: This results in a conservative loss of       results in a conservative loss of ERCW flow which is in excess of         ERCW flow which is in excess of typical system leakage under            typical system leakage under normal operating conditions.            normal operating conditions.
5.16 ERCW discharge flow is assumed     5.15 ERCW discharge flow is assumed     None to be directed over the hydraulic       to be directed to the hydraulic gradient rather than the cooling        gradient rather than the cooling tower basin.                            tower basin.
Technical Justification: This           Technical Justification: This increases the discharge flow            increases the discharge flow resistance and conservatively           resistance and conservatively reduces the flow available to the       reduces the flow available to the essential components.                   essential components.
CNL-22-043                                          Enc A3-15 of 29

Enclosure Attachment 3 Response to SCPB RAI-2 Table 1 Analysis Assumptions Previous LAR                              Current LAR                   Difference        Basis 5.17 The CCS supplies to the WBN        5.16 The CCS supplies to the               None            Generalized to Unit 1 RHR HX and the Non-regen         shutdown unit RHR HX and the                          dual-unit LAR.
letdown HX are assumed to be            Non-regen letdown HX are isolated.                               assumed to be isolated.
Technical Justification: With           Technical Justification: With the Unit 1 defueled, there are no heat      shutdown unit defueled, there are loads on these heat exchangers,         no heat loads on these heat and this preserves CCS flow for         exchangers, and this preserves the accident unit.                      CCS flow for the accident unit.
N/A  N/A                                5.17 It is assumed that the CCS heat       N/A             This assumption loads apply to the shutdown and                       addresses dual LOCA units independent of which                       unit equivalence unit is shutdown or which is                          and is specific to undergoing post-LOCA conditions.                      the current dual unit LAR.
Technical Justification: This is confirmed by inspection of the load list tables in the CCS load list calculation.
CNL-22-043                                           Enc A3-16 of 29

Enclosure Attachment 3 Response to SCPB RAI-2 Table 2 Design Input Previous LAR                         Current LAR                Difference Basis 3.1  The dual-unit, flow balanced and 3.1 The dual-unit, flow balanced and None benchmarked PROTO-FLO base           benchmarked PROTO-FLO base model of the ERCW system is          model of the ERCW system is obtained from the ERCW               obtained from the ERCW hydraulic model calculation.         hydraulic model calculation.
3.2  The ERCW system alignments       3.2 The ERCW system alignments       None and the ERCW flow rates to the       and the ERCW minimum applicable operating equipment       required flow rates to the are obtained from the ERCW           applicable operating equipment Pressure Drop calculation.           are obtained from the ERCW Pressure Drop calculation.
3.3  The equipment powered from       3.3 The equipment powered from       None each shutdown board is               each shutdown board is extracted from the electrical        extracted from the electrical single line drawings.                single line drawings.
CNL-22-043                                         Enc A3-17 of 29

Enclosure Attachment 3 Response to SCPB RAI-2 Table 2 Design Input Previous LAR                        Current LAR                  Difference              Basis 3.4  The design data for the new    3.7 The maximum allowable ERCW        The subject heat      This approach diesel generator jacket water      cooling water temperature for the exchanger thermal     ensures that any heat exchangers was obtained       emergency diesel generator        performance in        subsequent changes from the vendors data sheet       (EDG) jacket water heat           support of SDBD       to the heat included in Appendix 50 of the     exchangers was determined         cleaning is now       exchanger will be jacket water heat exchanger        from the jacket water heat        incorporated in the   evaluated for impact performance calculation.           exchanger performance             calculation rather    on the SDBD calculation, considering the      than the SDBD         cleaning analysis.
The design heat transfer           available flow rate predicted     cleaning analysis.
used for this analysis was         herein.                                                 The previous LAR 7,027,717 BTU/hr.                                                    The actual            used an overly The design heat transfer          acceptance criterion  conservative heat used for this analysis was        of the EDG jacket     transfer rate.
6,750,000 BTU/hr.                 water heat            The value of exchangers is used,   6,750,000 BTU/hr rather than an overly bounds the actual conservative value. operating heat load at 110% overload condition.
3.5  The PROTO-FLO/PROTO-HX         3.4 The PROTO-FLO/PROTO-HX            Both CCS trains A     Generalized to dual-model of the CCS is taken from     models of the CCS are taken       and B are evaluated   unit LAR.
Appendix I of the CCS Heat         from Appendix I of the CCS Heat   in the current LAR Exchangers Performance             Exchangers Performance calculation.                       calculation.
CNL-22-043                                       Enc A3-18 of 29

Enclosure Attachment 3 Response to SCPB RAI-2 Table 2 Design Input Previous LAR                         Current LAR                  Difference            Basis 3.6  The PROTO-HX models of the     3.5 The PROTO-HX models of the        None RHR, SFP, and CCS heat             RHR, SFP, and CCS heat exchangers are obtained from       exchangers are obtained from the CCS Heat Exchangers            the CCS Heat Exchangers Performance calculation, as        Performance calculation, as follows:                           follows:
* RHR HX - Appendix J
* RHR HX - Appendix J
* SFP HX - Appendix K
* SFP HX - Appendix K
* CCS HX - Appendix L
* CCS HX - Appendix L 3.7  The PROTO-HX model of the      3.6 The PROTO-HX model of the         None CSS heat exchanger is obtained     CSS heat exchanger is obtained from the CSS HX calculation.       from the CSS HX calculation.
N/A  N/A                            3.8 The maximum allowable ERCW        The subject heat    This approach cooling water temperature for the exchanger thermal   ensures that any (See also 3.13 below)              CSS HX was determined from        performance in      subsequent changes the CSS HX calculation,           support of SDBD     to the HX will be considering the available flow    cleaning is now     evaluated for impact rate predicted herein.            incorporated in the on the SDBD calculation rather  cleaning analysis.
(See also 3.14 below)             than the SDBD cleaning analysis.
CNL-22-043                                       Enc A3-19 of 29

Enclosure Attachment 3 Response to SCPB RAI-2 Table 2 Design Input Previous LAR                        Current LAR                  Difference                Basis 3.8  The SDBD room chiller          3.9 The maximum allowable ERCW        The subject heat        This approach is condenser energy balance           cooling water temperature for the exchanger thermal       conservative and performance spreadsheet is         SDBD room chiller condenser is    performance in          ensures that any taken from Appendix K-K of the     obtained from the SDBR HVAC       support of SDBD         subsequent changes 6.9 kV SDBD room HVAC              Equipment Performance             cleaning is now         to the heat calculation.                       calculation, considering the      incorporated in the     exchanger will be available flow rate predicted     calculation rather      evaluated for impact herein.                           than the SDBD           on the SDBD cleaning analysis.      cleaning analysis.
Impact to the In addition, the        maximum allowable calculation is revised; temperature curve it was discovered       from the change in that the calculation    design input was did not reflect a       negligible, on the retrievable source of order of 0.5&deg;F to design input for        1.0&deg;F in the flow certain heat            regime of interest.
exchanger dimensions. Further, there is a modification in progress to replace the SDBD chiller condensers that may or may not be completed before CNL-22-043                                       Enc A3-20 of 29

Enclosure Attachment 3 Response to SCPB RAI-2 Table 2 Design Input Previous LAR                      Current LAR                  Difference               Basis this LAR (Reference 1) is implemented - the calculation evaluates both cases and chooses the limiting condition.
3.9  The spreadsheet model of the 3.10 The maximum allowable           The subject heat       This approach is Main Control Room (MCR)           ERCW cooling water              exchanger thermal      conservative, chiller condenser is from         temperature for the MCR chiller performance in         reflects minor station Appendix A of the MCR HVAC        condenser is obtained from the  support of SDBD        configuration Equipment Performance             MCR HVAC Equipment              cleaning is now        changes, and calculation.                      Performance calculation,        incorporated in the    ensures that any considering the available flow  calculation rather     subsequent changes rate predicted herein.          than the SDBD          to the heat cleaning analysis. exchanger will be evaluated for impact In addition, the       on the SDBD calculation is revised cleaning analysis.
to reflect a prior re tubing of the MCR chiller condenser.
Further, there is a modification in progress to replace the MCR chiller CNL-22-043                                     Enc A3-21 of 29

Enclosure Attachment 3 Response to SCPB RAI-2 Table 2 Design Input Previous LAR       Current LAR            Difference      Basis condensers that may or may not be completed before this LAR (Reference 1) is implemented - the calculation evaluates both cases and chooses the limiting condition.
CNL-22-043                 Enc A3-22 of 29

Enclosure Attachment 3 Response to SCPB RAI-2 Table 2 Design Input Previous LAR                      Current LAR                   Difference               Basis 3.10 The spreadsheet model of the 3.11 The maximum allowable ERCW        The subject heat       This approach Electric Board Room (EBR)         cooling water temperature for the exchanger thermal      reflects minor station chiller condenser is from         EBR chiller condenser is          performance in         configuration Appendix 13 of the EBR HVAC       obtained from the EBR HVAC        support of SDBD        changes and Equipment Performance             Equipment Performance             cleaning is now        ensures that any calculation.                      calculation, considering the      incorporated in the    subsequent changes available flow rate predicted     calculation rather     to the heat herein.                           than the SDBD          exchanger will be cleaning analysis. evaluated for impact on the SDBD In addition, the       cleaning analysis.
calculation is revised Incorporating the to reflect a prior     retubing effort re-tubing of the EBR   removed excess chiller condensers. margin from the calculation.
CNL-22-043                                      Enc A3-23 of 29

Enclosure Attachment 3 Response to SCPB RAI-2 Table 2 Design Input Previous LAR                         Current LAR               Difference Basis 3.11 The limiting engineering safety 3.12 The limiting ESF room cooler    None feature (ESF) room cooler            ERCW inlet temperatures during ERCW inlet temperatures during       LOCA conditions are from the loss coolant accident (LOCA)         Minimum ESF Cooler ERCW conditions as a function of          Flow Rates versus Entering ERCW flow rate are from the          ERCW Temperatures during Minimum ESF Cooler ERCW             LOCA Conditions calculation.
Flow Rates versus Entering ERCW Temperatures during LOCA Conditions calculation.
3.12 The limiting heat exchanger     3.13 The heat exchanger outlet       None outlet temperature limits are        temperature limits are obtained obtained from the respective         from the respective system Op system Op Mode calculations.         Mode calculations.
CNL-22-043                                        Enc A3-24 of 29

Enclosure Attachment 3 Response to SCPB RAI-2 Table 2 Design Input Previous LAR                           Current LAR                 Difference              Basis 3.13 The maximum load on the CSS      3.14 The maximum load on the CSS      Previous LAR CSS     The previous limit of heat exchanger is based on the        heat exchanger is based on the   HX duty =            5% tube plugging maximum post-LOCA                     maximum post-LOCA                81,294,921 BTU/hr. was justifiable due to containment sump temperature          containment sump temperature     Based on design      the known CSS HX of 158.2&deg;F and associated spray       of 164.8&deg;F and associated spray  max fouling and 5%   condition and time flow rate of 4000 gpm consistent      flow rate of 4000 gpm consistent tube plugging.       limit on the previous with the design basis LOCA            with the design basis LOCA                            LAR, and analysis.                             analysis.                        Current LAR CSS      conservative for HX duty =            purposes of 87,323,731 BTU/hr. calculating Two limits are       maximum heat evaluated and the    transfer. The actual more conservative is allowable tube used: 1) minimum     plugging limit is required heat        10%.
transfer credited in the LOCA analysis    The previous LAR based on max. sump   developed the CSS temperature of       HX acceptance 164.8&deg;F, design max. criterion of fouling and 10%      81,294,921 BTU/hr plugged tubes and 2) based on the maximum allowable    maximum post-ERCW outlet          LOCA containment temperature of 130&deg;F sump temperature of based on the sump    158.2&deg;F determined temperature of       by a Westinghouse CNL-22-043                                          Enc A3-25 of 29

Enclosure Attachment 3 Response to SCPB RAI-2 Table 2 Design Input Previous LAR       Current LAR           Difference               Basis 158.2&deg;F, zero fouling study in support of and zero plugged      increasing the UHS tubes.                temperature to 88&deg;F.
That analysis predicted the CSS HX performance margin of 39%.
The current LAR analysis applied the maximum post-LOCA containment sump temperature of 164.8&deg;F from the current LOCA analysis of record (based on the current UHS temperature limit of 85&deg;F) to determine the CSS HX maximum duty acceptance criterion of 87,323,731 BTU/hr. This analysis demonstrates CSS CNL-22-043                 Enc A3-26 of 29

Enclosure Attachment 3 Response to SCPB RAI-2 Table 2 Design Input Previous LAR                          Current LAR                Difference         Basis HX margins of 24%
and 31% for a 1/2 B-B SDBD out of service or for a 1/2 A-A SDBD out of service, respectively.
Continued use of a 158.2&deg;F inlet temperature in the current analysis for the exit-temperature-limited case is justified in the CSS calculation.
3.14 The maximum LOCA unit RHR       3.15 The maximum LOCA unit RHR       None heat exchanger duty is based on      heat exchanger duty is based on the maximum RHR temperature          the maximum RHR temperature of 166.2&deg;F and RHR flow rate of      of 166.2&deg;F and RHR flow rate of 3100 gpm from the CCS HX             3100 gpm from the CCS HX Performance calculation.             Performance calculation.
CNL-22-043                                        Enc A3-27 of 29

Enclosure Attachment 3 Response to SCPB RAI-2 Table 2 Design Input Previous LAR                           Current LAR                Difference         Basis 3.15 The pressure switch setpoint for 3.16 The pressure switch setpoint for None 0-PS-67-206 and 209 of 37 psig        0-PS-67-206 and 209 of 37 psig is obtained from the applicable       is obtained from the applicable Nuclear Engineering Setpoint          NESSD.
Scaling Document (NESSD).
3.16 The flow indicating switch       3.17 The flow indicating switch       None setpoint of 350 gpm for               setpoint of 350 gpm for 0-FIS-67-206 and 209 is               0-FIS-67-206 and 209 is obtained from the applicable          obtained from the applicable NESSD.                                NESSD.
N/A  N/A                              3.18 The CCS flow rates delivered to  N/A             This design input is the RHR and SFP heat                             specific to the exchangers by the single 1B-B                    current LAR.
pump for the SDBD 2B-B out of service (OOS) case are obtained from the CCS Pressure Drop calculation.
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Enclosure Attachment 3 Response to SCPB RAI-2 Table 2 Design Input Previous LAR                   Current LAR          Difference              Basis N/A  A/B Train CCS (HX) Duty = N/A A/B Train -CCS HX Duty = A conservative and    The predicted CCS 106,183,506 BTU/hr.           88,764,506 BTU/hr.       beyond design basis   HX duty exceeds the SFP duty of           overly conservative 50,215,000 BTU/hr     acceptance criterion for the shutdown unit in the previous LAR was added to LOCA     as well as the unit duty in the      correct value in the previous LAR          current LAR.
analysis. The correct value is 88,764,506 BTU/hr.
CNL-22-043                                 Enc A3-29 of 29}}