AEP-NRC-2024-10, Form OAR-1, Owners Activity Report
| ML24038A338 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 02/07/2024 |
| From: | Scarpello M Indiana Michigan Power Co |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| AEP-NRC-2024-10 | |
| Download: ML24038A338 (1) | |
Text
Indiana Michigan Power Cook Nuclear Plant One Cook Place Bridgman, Ml 49106 indianamichiganpower.com An ARPCcmpany
BOUNDLESS ENERG Y-
February 7, 2024 AEP-NRC-2024-10 10 CFR 50.55a
Docket No.: 50-315
U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555-0001
Donald C. Cook Nuclear Plant Unit 1 Form OAR-1, Owner's Activity Report
Indiana Michigan Power Company, the licensee for Donald C. Cook Nuclear Plant (CNP) Unit 1, is providing as Enclosure 1 to t~is letter, Form OAR-1, Owner's Activity Report, for lnservice Inspection activities performed at CNP Unit 1 through the completion of the Unit 1 Cycle 32 Refueling Outage.
This report meets the requirements of the American Society of Mechanical Engineers (ASME) Code Case N-532-5, "Repair/Replacement Activity Documentation Requirements and lnservice Inspection Summary Report Preparation and Submission Section XI, Division 1." This code case is used as an alternative to the requirements of the ASME Boiler and Pressure Vessel Code,Section XI, Article IWA-6000, as specified in Regulatory Guide 1.147, "lnservice Inspection Code Case Acceptability, ASME Section XI, Division 1," Revision 20, for the current inspection interval.
The Authorized Code Inspection Company is Bureau Veritas Inspection and Insurance Company, of Lynn, Massachusetts. The Authorized Nuclear lnservice Inspector is Howard M. Burkhart, Jr.
This letter also provides, as Enclosure 2, a copy of the analytical evaluation of relevant conditions identified during the Unit 1 operating period between Cycle 31 and Cycle 32 outages as required by ASME Boiler and Pressure Vessel Code,Section XI, Subparagraph IWD-3132.3.
There are no new or revised commitments in this letter. Should you have any questions, please contact me at (269) 466-2649.
~-e~rp,i
Michael K. Scarpello Director of Regulatory Affairs
RAW/sjh U. S. Nuclear Regulatory Commission AEP-NRC-2024-10 Page 2
Enclosures:
- 1. Form OAR-1, Owner's Activity Report for Donald C. Cook Nuclear Plant Unit 1 Cycle 32 Refueling Outage
- 2. Evaluation of Relevant Conditions found during Unit 1 Operating Cycle 32
c: EGLE - RMD/RPS J. B. Giessner - NRC Region Ill NRC Resident Inspector N. Quilico - MPSC R. M. Sistevaris - AEP Ft. Wayne S. P. Wall - NRC Washington D.C.
A. J. Williamson - AEP Ft. Wayne Enclosure 1 to AEP-NRC-2024-10
Form OAR-1, Owner's Activity Report for Donald C. Cook Nuclear Plant Unit 1 Cycle 32 Refueling Outage D. C. Cook Nuclear Unit 1 FORM OAR-1 OWNER'S ACTIVITY REPORT
Report Number 1-2023-5-2-01
Plant Donald C Cook Nuclear Plant, One Cook Place, Bridgman, Michigan 49106
Unit No. 1 Commercial service date 8/23/1975 Refueling outage no. U1C32 (if applicable)
Current inspection interval 5th for Comeonents and Sueeorts (C&S} and 3rd for Containment ISi (CISI) Program (1s~ 2nd, 3rd, 4th, other)
Current inspection period 2nd for C&S and 2nd for CISI (Is~ 2nd, 3rd)
Edition and Addenda of Section XI applicable to the inspection plans 2013 Edition/No Addenda
Date and revision of inspection plans 5/10/2023 Revision 6 for C&S, 3/10/2022 Revision 1 for CISI
Edition and Addenda of Section XI applicable to repair/replacement activities, if different than the inspection plans Edition and Addenda are the same as the lnseection Plans
Code Cases used for inspection and evaluation : N-722-1 for C&S (If applicable, Including cases modified by Case N-532 and later revisions)
CERTIFICATE OF CONFORMANCE
I certify that (a) the statements made in this report are correct; (bl the examinations and tests meet the Inspection Plan as required by the ASME Code,Section XI; and (c) the repair/replacement activities and evaluations supporting the completion of U1C32 conform to the requirements of Section XI. (refueling outage number)
Signed w~CRA.~~, ISi P~ram Owner Date I / I 7 l :z_oz_ j Owners or Owne(s Oeslgnee, Tide
CERTIFICATE OF INSERVICE INSPECTION
I, the undersigned, holding a valid commission issued by the National Board of Boiler and Pressure Vessel Inspectors and employed by 6!.!!:§i!!.! ~lili!S ln§~gtion l!D!I !nsu[i!ru;~ ~Q!Dl!i!Dlr'. of L~n.MA have Inspected the Items described in this Owner's Activity Report, and state that, to the best of my knowledge and belief, the Owner has performed all activities represented by this report in accordance with the requirements of Section X I.
By signing this certificate neither the Inspector nor his employer makes any warranty, expressed or implied, concerning the repair/replacement activities and evaluation described In this report. Furthermore, neither the Inspector nor his employer shall be liable in any manner for an _y personal Injury or property damage or a loss of any kind arising from or connected with this Inspection.
'21..,,,~ ~CJ - d~. Commissions 9o.U A:Z: XS :t. I\\J R Inspector's Signa!Ure {J National Board Number and Endorsement
Date t '1 -:r/:u.J:10::, ~.
Page 1 of3
~- -
I - J D. C. Cook Nuclear Unit 1 Table 1 Items with Flaws or Relevant Conditions That Required Evaluation for Continued Service
Examination Category and Item Number Item Description Evaluation Description A through wall leak was identified on a Class 3 Essential Service Water (ESW) tubing connection supplying an
0-8 02.10 was evaluated as acceptable per Pressure retaining components Auxiliary Feed Pump Room Cooler precooler. The leak ASME Section XI IWD-3132.3 until the connection was replaced. Reference AR 2022-6991.
A through wall leak was identified on a Class 3 Essential Service Water (ESW) tubing connection supplying an
O-B 02.10 Pressure retaining components Auxiliary Feed Pump Room Cooler precooler. The leak was evaluated as acceptable per ASME Section XI IWD-3132.3 until the connection can be replaced. Reference AR 2023-3596.
Page 2 of3 D. C. Cook Nuclear Unit 1 Table 2 Abstract of Repair/Replacement Activities Required for Continued Service
Code Class Item Description Description of Work Date Completed Repair/Replacement Plan Number
1-HV-AFP-T2AC (TURBINE Replace Precooler with Through Wall Leak, AR 2022-3 DRIVEN AUX FEED PUMP 12/13/2022 WO-C10038372004 ROOM COOLER T2AC) 6991 1-GRH-V29 (RESIDUAL HEAT REMOVAL SYS 2 ISOMETRIC DWG 1-RH-13 3 Replace Damaged Support Items, AR 2019-2928 INCH VARIABLE RATE 5/31/2023 WO-C10010105002 SPRING TYPE PIPE SUPPORT)
Page 3 of 3 Enclosure 2 to AEP-NRC-2024-10
Evaluation of Relevant Conditions found during Unit 1 Operating Cycle 32 1-HV-AFP-T2AC ESW Leak (AR 2022-6991)
Title:
1-HV-AFP-T2AC ESW Leak Revision Summary
Revision 1 - Clarified "OPERABILITY Recommendation" as it relates to 1-HV-AFP-T2AC in Section 7 and its ability to provide cooling capacity with the condition of the ESW leak. While the leak is within the code class 3 boundary of the room cooler, it does not impact the room cooler's function to provide cooling to the Unit 1 TDAFP room.
Section 1 - Description
On 9/2/2022, a sample was taken from the water exiting the drip catch of 1-HV-AFP-T2AC, Turbine Driven Aux Feed Pump Room Cooler T2AC. This sample determined chlorine was present in the water, which is an indication of a leak from Essential Service Water within the housing of the room cooler. An investigation of the leak determined the leak was at the brazed connection of the 5/8" OD tube exiting the supply manifold (the supply manifold is identified as the pre-cooler on OP-1-51138).
Section 2 -Affected SSC(s)
Unit 1 Auxiliary Feedwater System (AFW)
1-PP-4, Turbine Driven Auxiliary Feedwater Pump (TDAFP)
1-HV-AFP-T2AC, Turbine Driven Aux Feed Pump Room Cooler T2AC Unit 1 West Essential Service Water System (ESW)
1-PP-7W, West Essential Service Water Pump
Unit 2 East Essential Service Water System (Due to ESW system cross-tie) 2-PP-7E, East Essential Service Water Pump (Due to ESW system cross-tie)
Section 3 - Extent of Condition
A review of the Non-Conformances (NCE) List determined the following were outstanding against the affected SSCs:
Inability to supply emergency make-up water to Component Cooling Water system Plant Reliability List ID 060
This condition, identified during the 2015 NRC CDBI inspection, determined that there was no safety-related make-up supply for the Component Cooling Water (CCW) system.
As an immediate action to establish safety-related make-up, a temporary modification was incorporated into a new procedure, 12-OHP-5030-016-001 "Supplying ESW to CCW for Makeup Using a Temporary Configuration Change". This uses ESW on the outlet of a CCW heat exchanger to provide make-up to the affected CCW train's CCW pump. The condition being evaluated in this ODE is not impacted by the condition for the temporary modification.
Installed check valves did not have required Certified Material Test Reports (CMTR) Plant Reliability List ID 091 1-HV-AFP-T2AC ESW Leak (AR 2022-6991)
This condition identified that 1-ESW-101E, 1-ESW-101W, 2-ESW-102E, and 1-ESW-102W do not have required CMTRs. The Evaluation in AR 2020-0200 determined that the Commercial Grade Dedication Plan verified the critical characteristics necessary to demonstrate that the valves can perform their design functions. This condition is related to verbatim compliance with the code requirement to meet the original specification. The condition being evaluated in this ODE is not impacted by the condition for the lack of CMTRs.
Section 4 - Affected Safety Functions
- 1) Auxiliary Feedwater provides makeup flow to steam generators in event of:
a) Loss of main feedwater
b) Main feedwater line break
c) Main steam line break d) Loss of Coolant accident
e) Steam Generator tube rupture
f) Loss of offsite power
- 2) Provides flow from the TDAFP to the steam generators during a Station Blackout (SBO)
The above functions are potentially affected if the Turbine Driven Auxiliary Feedwater pump were declared inoperable due to unacceptable room temperatures, or if the INOPERABLE Room Cooler made the Turbine Driven Auxiliary Feedwater pump INOPERABLE for any reason.
Per PMP-7030-OPR-001, Attachment 6, Guidance on Determining "Mission Time" of an SSC, the AFW pump mission time is 7 days.
- 1) The Essential Service Water System provide cooling water flow to the following:
a) CCW Heat Exchangers b) CTS Heat Exchangers
c)AFW Pump Room Coolers
d) EDG Lube Oil Cooler, Jacket Water Cooler & Air After Coolers
e) Control Room Chiller Package and Air Handling Units The above functions are potentially affected if the Unit 1 West or Unit 2 East Essential Service Water system were declared inoperable due to unacceptable system leakage. The ESW system is an SSC that performs a long-term mitigation safety function post-accident, per PMP-7030-OPR-001, the ESW mission time is 30 days.
1-HV-AFP-T2AC ESW Leak (AR 2022-6991)
Section 5 - Technical Specification Requirements Impacted
3 7 S Aulll ary Feedwatr (AFW ) $'s, tem
LCO 3 7 S Tht eeAFW tr all be OPERABIE.
*--- NO'E --- ----Only one JEW tra!J) ch udes M'I otor drl'eR pump, Is requ ired lo be OPERABLE M ODE 4
I..,._ ---
APPLICABILJY: MODES 1, 2, and 3 MODE 4wh 1en stean gendll1 tor Is rel ed upon for heat removal
3 7. 8 Essential ServlceW ater (ESN )Sys tem
LCO 3 l8 lNo ESW trahs shall be OPlflASILE
==- -= N' OTE -*-~- -- ****** -
When ' ESN 'Im n s cro sstledwl lhlh e '8SCda ted Unit 2 ESW train
1n l OPERABILITY oflhe ESN n lrclud1es the associated Unit 2 ESN '
pump
APPLICABIU TY. M) DES 1, 2 3 aid 4.
Section 6 - Other Design / Licensing Basis Requirements Impacted AFW Pump Room Protection (UFSAR 14.4.9.2, Rev 30.9)
The AFW pump rooms have been modified to protect them from the consequences of a HELB in the Turbine Building as well as a break of the 4 inch main steam piping in the TDAFW pump room. The rooms have been completely isolated from each other as well as the Turbine Building by maintaining the doors closed, removing the ventilation fans, and sealing openings. Safety related coolers are installed in each TDAFP room to maintain the room temperature at or below 104°F.
Redundant coolers have been provided in the TDAFW pump room. The coolers are powered from opposite divisions and are supplied with ESW from the same division as their power.
Unit 1 TDAFP Room Flooding (PRA-FLOOD-007, Section 5.42)
Flood Area 038 (Fire Area 017E) is the assigned area for the Unit 1 TDAFP room. Per this analysis, the floor drain capacity within this area is 642. 1 gpm. This analysis also recognizes the propagation path out of the room through the double leaf doors into the AFP hallway. While this propagation would increase allowable flooding capacity, for the purpose of this evaluation, the maximum floor drain capacity will be used as a conservative measure.
1-HV-AFP-T2AC ESW Leak (AR 2022-6991)
ESWAcceptable Amount of Leakage for Each Train (MD-12-ESW-112-N, Section 5.0 and 6.0)
The acceptable amount of leakage out of each train of ESW is documented below:
Train Leakagel.Aln it,g.pm 720 1.36S 93S 1.230
Margin Assessment
This calculation establishes a maximum leakage limit for the ESW system. The result for each train is effectively the margin that train has for system leakage. This result can be used for assessing Operability of the ESW system when leakage is identified.
Section 7 - OPERABILITY Recommendation
Engineering recommends the Unit 1 West ESW train and Unit 2 East ESW train be considered OPERABLE with respect to the leakage identified within the 1-HV-AFP-T2AC room cooler skid being within acceptable train limits. This recommendation is applicable in MODES 1 through 4.
Engineering recommends 1-HV-AFP-T2AC be considered INOPERABLE, BUT FUNCTIONAL in its ability to provide cooling capacity to the Unit 1 TDAFP room with ESW flow in-service. This recommendation is applicable in MODES 1 through 4.
This evaluation determined that it is acceptable for continued service of 1-HV-AFP-T2AC with cooling flow from the Unit 1 West ESW train. It was determined that the maximum potential leakage from this condition was within the acceptable limits of the Unit 1 West ESW train and Unit 1 TDAFP room flooding capacity. If ESW cooling flow is isolated from 1-HV-AFP-T2AC, these recommendations remain valid as the ESW leakage would reduce to zero. If ESW flow was isolated, but the isolation valve exhibits leak by, leakage from this condition would remain bounded by this evaluation as it would only decrease from the maximum calculated.
1-HV-AFP-T2AC ESW Leak (AR 2022-6991)
Section 8 - Basis for OPERABILITY Conclusion
From NRC Inspection Manual Chapter 0326 :
Methods Acceptable to Evaluate Structural Integrity
Pipe ASME Code Section NRC Approved code case Class/ Energy XI / Construction Alternative e.g. RG N-513 GL 90-05 Code approved code case Class 1/ HE X X Class 2/ HE X X Class 2/ ME X X X Class 3/HE X X X Class Z ME X X X X
08. 13 Operational Leakage from ASME Code Class 1, 2, and 3 Components The NRC staff does not consider through-wall leakage in components to be in accordance with the intent of the ASME Code or construction code, unless intentionally designed to be there such as sparger flow holes. Therefore, components with through-wall leakage would not meet ASME Section XI or construction code requirements. Thus, unless a 100% through-wall flaw is evaluated and found acceptable using an applicable methodology as described in the table above and in which all provisions are met including any additional requirements or limitations imposed (e.g. by the NRC approved code case), the system or component does not demonstrate structural integrity.
ASME Class 2 and 3 Components
Upon discovery of leakage from a TS-required Class 2 or Class 3 component ("Time of Discovery" for Performance Indicator and risk/PRA evaluations), the component should be evaluated to determine if the flaw is acceptable and demonstrate structural integrity.
The licensee must also assess the impact of the leak on the SSC's ability to provide sufficient flow for the associated mission time and any impact the leakage has (if any) on nearby components and their ability to perform their specified safety function(s).
Per the reference above, ASME 2013 Section XI, Section IWD-3100, Evaluation of Examination Results was utilized for to evaluate the leakage from the Class 3 piping that is part of 1-HV-AFP T2AC. Specifically section IWD-3132.3, Acceptance by Evaluation, criteria (a) was used.
IWD-3132.3 Acceptance by Evaluation
A component containing relevant conditions is acceptable for continued service if an evaluation demonstrates the component's acceptability in accordance with (a) or (b) below.
(a) The evaluation analysis and evaluation criteria shall be specified by the Owner.
Components accepted for continued service based on evaluation shall be subsequently examined in accordance with IWD-2420(b) and IWD-2420(c). If the subsequent IWD-2420(b) and IWD2420(c) examinations reveal that the relevant 1-HV-AFP-T2AC ESW Leak (AR 2022-6991)
conditions remain essentially unchanged, or the changes in the relevant conditions are within the limits predicted by the evaluation, and the design inputs for the evaluation have not been affected by activities such as power uprates, the existing evaluation may continue to be used, provided it covers the time period until the next examination.
As the "Owner", the "evaluation analysis" referenced above is being specified as the evaluation completed in this ODE. As the "Owner", the "evaluation criteria" is being specified as the stated requirements listed in Sections 5 and 6 above.
Investigation of the ESW leak within 1-HV-AFP-T2AC was performed under WO C10038372-003. This investigation determined the leak was at the brazed connection of the 5/8 inch OD tube exiting the supply manifold (the supply manifold is identified as the pre-cooler on OP 51138). For the purpose of this evaluation, 3/4 inch was used as the bounding maximum potential leakage path as this encompasses all of the 1-HV-AFP-T2AC piping between the supply and return manifolds. Because the through-wall leakage flaw could not be accurately measured with practices reasonable accessible at DC Cook, this evaluation will assume a worst-case bounding scenario of a guillotine cut of a 3/4 inch pipe. This results in two leakage paths, both the supply header and return header sides of the cut.
The calculation performed below was referenced from Crane Technical Paper No. 410, Flow of Fluids Through Valves, Fittings, and Pipe. Equation 6-27 was used for the "Discharge of Fluid Through Valves, Fittings, and Pipe; Darcy's Formula ". The diameter of the pipe (d) was bounded, as stated above, as 3/4 inch. Head loss (hl) was calculated using the 1ST High Action limit referenced in TDB-1-FIG-15-1, Safety Related Pump lnservice Test Hydraulic Reference, for the Unit 1 West ESWpump, 1-PP-7W. From TDB-1-FIG-15-1, this 1ST High Action limit is 72.0 psid, which results in a head loss of 166.32 feet. Using the high action limit is conservative as the Unit 1 West ESW pump normally operates in the range of 65 psid and the additional differential pressure will result in a higher leakage flow rate for the purposes of this evaluation.
The Resistance Coefficient (K) was determined using the "Pipe Exit" K values in the Crane Technical Paper No. 410, Appendix A - Physical Property of Fluids, page A-30. The value listed is K = 1.0 for any type of pipe exit. No further additions of resistance were added, such as pipe friction or bends, due to the unknown location of the leak as stated above. This is conservative because any additional friction considerations would result in lower flow leakage flow rates.
d := 0.75 LlP := 72.0
hL :=. LlP
- 2.31 =- 1 66.32
2 ~ r,;:;
Q== 19.64 * ( d)
The calculation as described and shown above determined that leakage out of a 3/4 inch pipe is 142.5 gpm.
In relation to Unit 1 West ESW train system leakage limits, the leakage amount of 142.5 gpm is applied as this is the amount of supply header leakage from one side of the described guillotine cut. Because MD-12-ESW-112-N concludes that the referenced ESW train maximum leakage values are for an entire train, the return header leakage amount of an additional 142.5 gpm will also be considered. This results in a total Unit 1 West ESW train leakage amount of 285 gpm.
This value is well within the maximum train leakage limit of 1,365 gpm and provides sufficient margin.
In the event of a design basis accident which would result in all four (4) ESW pumps being in service, the system operates at 105 psig per the Design Basis Document. At this pressure the leak rate would be 172 gpm per end of the break for a total leakage of 344 gpm. This is still well within the allowed leakage of 720 gpm for the Unit 1 East train.
Similarly for the same reasons above, the Unit 2 East ESW train system leakage limits would not be exceeded from the calculated total leakage of either 285 gpm or 344 gpm depending on pump configuration. This calculated total leakage provides sufficient margin to the 935 gpm maximum train leakage limit.
Per PMP-4030-001-001, "Calculation TH-00-05 has determined that the TDAFP remains operable with a total loss of room cooling, provided the ambient temperature remains below 104°F. The door to the room may be OPEN, provided we are in compliance with LCO 3.0.8."
This concludes that the Unit 1 TDAFP room cooler remains Operable with a total loss of room cooling up to 104°F.
In relation to Unit 1 TDAFP room flooding, the floor drain capacity of the room is 642.1 gpm. The calculated maximum potential leakage from this condition of 285 gpm or 344gpm is below the floor drain capacity with sufficient margin.
These conclusions are applicable to all MODES when the ESW and AFW systems are required to be OPERABLE.
These conclusions above show that the requirements listed in Sections 5 and 6 are met in relation to the "evaluation criteria" for ASME Section XI. The condition has been determined acceptable by evaluation. Because this was determined acceptable per ASME code, this is not considered a Non-Conforming condition.
Section 9 - Recommended Corrective Actions
AR 2022-6991-2, CA-If not repaired prior to the next refueling outage, track the subsequent examination of 1-HV-AFP-T2AC in accordance with IWD-2420(b) and IWD-2420(c) for re examination of the flaw during the next inspection period listed in the Inspection Program (U1C32 RO, U1C33 RO, or U1C34 RO). Due 12/31/2026 (end of U1C34 RO).
Section 10 - Supporting Documentation UFSAR Chapter 14.4.9.2, Rev 30.9
IFPRA-001, Internal Flooding - Development of Flooding Zones, Source, Walkdowns, Qualitative Screening, and Initial Flooding Scenario Characterization 1-HV-AFP-T2AC ESW Leak (AR 2022-6991)
PRA-FLOOD-007, Floor Drains Capacity
MD-12-ESW-112-N, Impact of ESW Supply Header Crosstie Shutoff Valve Leakage on the ESW system
PMP-4030-001-001, Impact of Safety Related Ventilation on the Operability of Technical Specification Equipment PMP-7030-OPR-001, Operability Determination
TDB-1-FIG-15-1, Safety Related Pump lnservice Test Hydraulic Reference
ITSA-U1, Unit 1 Technical Specifications OP-1-5113B, Flow Diagram Turbine Driven Aux Feed Pump Room Coolers
NRC Inspection Manual Chapter 0326 I
ASME 2013 Section XI WO C10038372-003 1-HV-T1AC ESW Leak (AR 2023-3596)
Operability Determination from AR 2023-3596:
The ESW leak identified in AR 2023-3596 on the 1-HV-AFP-T1AC of approximately 1 gpm is bounded by the ODS performed under AR 2022-6992-1 for an ESW leak on 2-HV-AFP-T2AC.
This ODS determined that a leak of a sheared tube would be approximately 140 gpm and that ESW would still be operable. A 1 gpm leak is well within the allowed leakage and does not impact ESW Operability.
Operability Determination Support for AR 2023-3596 from AR 2022-6992:
==
Description:==
On 9/2/2022, a sample was taken from the water exiting the drip catch of 2-HV-AFP-T2AC, Turbine Driven Aux Feed Pump Room Cooler T2AC. This sample determined chlorine was present in the water, which is indicating of an Essential Service Water leak within the housing of the room cooler.
Assignment:
An Operability Determination Support (ODS) was requested by Operations to confirm that the ESW leak on 2-HV-AFP-T2AC was within associated system leakage requirements.
Affected SSC(s):
Unit 2 Auxiliary Feedwater System (AFW)
2-PP-4, Turbine Driven Auxiliary Feedwater Pump (TDAFP) 2-HV-AFP-T2AC, Turbine Driven Aux Feed Pump Room Cooler T2AC
Unit 2 West Essential Service Water System (ESW)
2-PP-7W, West Essential Service Water Pump Unit 1 East Essential Service Water System (Due to ESW system cross-tie)
1-PP-7E, East Essential Service Water Pump (Due to ESW system cross-tie)
Assessment:
Investigation of the ESW leak within 2-HV-AFP-T2AC, performed under WO C10038371-003, determined the ESW leak was at the mechanical connection between the pre-cooler supply manifold and the tube sheet (Figures 1 and 2). Water could be visually identified as exiting from a specific location at the entrance of a tube, which are 5/8 inch OD. Assuming the entire tube fails and becomes a tube sized leak from both the supply and return sides, the following calculation was performed:
Crane Technical Paper No. 410, Flow of Fluids Through Valves, Fittings, and Pipe, Equation 6-27 was used for the "Discharge of Fluid Through Valves, Fittings, and Pipe; Darcy's Formula".
The diameter of the pipe (d) was bounded as 3/4 inch. Head loss (hl) was calculated using the 1ST High Action limit referenced in TDB-2-FIG-15-1, Safety Related Pump lnservice Test Hydraulic Reference, for the Unit 2 West ESW pump. From TDB-2-FIG-15-1, this 1ST High Action limit is 70.2 psid, which results in a head loss of 162.162 feet. Using the high action limit is conservative as the Unit 2 ESW pump normally operates in the range of 65 psid and the 1-HV-T1AC ESW Leak (AR 2023-3596)
additional differential pressure will result in a higher leakage flow rate for the purposes of this evaluation. The Resistance Coefficient (K) was determined using the "Pipe Exit" K values in the Crane Technical Paper No. 410, Appendix A-Physical Property of Fluids, page A-30. The value listed is K = 1.0 for any type of pipe exit. No further additions of resistance were added, such as pipe friction or bends. This is conservative because any additional friction considerations would result in lower flow leakage flow rates.
d:=0.75 LlP:=70.2 K:=1 hL ;=.41'
- 2.31 - 162162 +
2 Ar,;;
Q== 19.64 * ( d)
- VK = 140.682
The following criteria e<ists as it relates to maximum allowable leakage from this identified leak:
ESWAcceptable Amamt of Leakage for Each Train (MD-12-ESW-112-N, Section 5.0 and 6.0)
The Acceptable amo1.11t of leakage out of each train of ESW is documented below:
Train lakaff Lim,, gpm Unit J East _ 720 Unit J Wes t 1,36S Unit 2 Ea st 93S Unit 2 W est 1,230
Unit 2 TDAFP Room Flooding (PRA-FLOOD-007, Section 5.45)
Flood Area 041 (Fire Area 01 ?F) is the assigned area for the Unit 2 TDAFP room. Per this analysis, the floor drain capacity within this area is 627.4 gpm. This analysis also recognizes the propagation path out of the room through the double leaf doors into the AFP hallway. While this propagation would increase allowable flooding capacity, for the purpose of this evaluation, the maximum floor drain capacity will be used as a conservative measure.
ASME 2013 Section XI, IWD-3511.1, Visual Examination, VT-2
A component whose visual examination (IWA-5240) detects any of the following relevant conditions shall meet IWD-3132 and IWA-5250 prior to continued service:
1-HV-T1AC ESW Leak (AR 2023-3596)
(b) leakage in excess of limits established by the Owner from mechanical connections (such as pipe caps, bolted connections, or compression fittings) or from components provided with leakage-limiting devices (such as valve packing glands or pump seals)
In relation to the criteria listed above, a 3/4 inch pipe on the Unit 2 West ESW train will have a maximum leak rate of 140.7 gpm. Considering a guillotine cut pipe will leak from two ends, this is doubled to 281.4 gpm. This maximum leak rate from two ends is within the maximum allowed leakage from both the Unit 2 West ESW train and Unit 1 East ESW train. This leak rate is also below the maximum floor drain capacity of the Unit 2 TDAFP room. Due to this leak being within the ISi Class 3 piping boundary, ASME Code must be considered. Per the determinations above, this leakage is not in excess of limits established by the Owner (DC Cook) for this mechanical connection.
==
Conclusion:==
Engineering recommends the Unit 2 West ESW train, Unit 1 East ESW train, and Unit 2 TDAFP be considered OPERABLE in relation to the ESW leak documented in AR 2022-6992.
Figure 1 - Field Walkdown Picture