ML17229B084
ML17229B084 | |
Person / Time | |
---|---|
Site: | Saint Lucie |
Issue date: | 04/07/1999 |
From: | FLORIDA POWER & LIGHT CO. |
To: | |
Shared Package | |
ML17229B083 | List: |
References | |
PSL-ENG-SEMS-98, PSL-ENG-SEMS-98-102, NUDOCS 9904120110 | |
Download: ML17229B084 (84) | |
Text
{{#Wiki_filter:St. Lucie Unit 2 Docket No. 50-389 L-99-90 Enclosure Attaclunent l PSL-ENG-SEMS-98-102 Rev 2 Page 1 of 15 ENGINEERING EVALUATIONOF ECCS SUCTION LINES ST LUCIE NUCLEAR PLANT UNIT 2 PSL-ENG-SEMS-98-1 02 REVISION 2 FLORIDA POWER & LIGHTCOMPANY NUCLEAR ENGINEERING DEPARTMENT SAFETYRELATED 9904i20ii0 990407 PDR ADQCK 05000389 8 PDR~
PSL-ENG-SEMS-98-102 Rev 2 Page 2 of 15 REVIEW ANDAPPROVAL RECORD NT ST LUCIE UNIT 2 TITLE Engineering Evaluation of ECCS Suction Lines LEAD DISCIPLINE Mechanical ENGINEERING ORGANIZATION FPL En ineerin REVIEW/APPROVAL: GROUP INPUT REVIEW N/A INTERFACE TYPE PREPARED VERIFIED APPROVED FPL APPROVED* MECH ELECT 1&C CIVIL Design Basis ** CSI FUELS OTHER N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A p yy N/A z/sg N/A N/A N/A N/A N/A For Contractor Evals As Determined By Projects "*Review Interface As A Min On AII 10CFR50.59 Evals and PLAs FPL PROJECTS APPROVAL: DATE: OTHER INTERFACES: A tech En ineerin Services, Inc. Form 24, Rev 2 (7/97)
i bL-i=Nb-bCM5.50 IV@ Rev 2 Page 3 of 15 I. PURPOSE / SCOPE
Background:
AR 960294 identified stress corrosion cracking (SCC) concerns with regard to welds in the Unit 1 ECCS suction piping located in the trench between the RWT and RAB. As part of the STAR's corrective actions, PMAI 96-11-222 was issued to inspect a sample of welds on the Unit 2 ECCS suction piping during the 1998 Cycle 11 Refueling Outage. In a related issue, CR 98-0047 was written to address external corrosion deposits identified on the Unit 2 ECCS suction piping located in the outside pipe tunnel. This CR's corrective actions included Work Order 98002077 to inspect the Unit 2 A and B ECCS piping before the spring of 1999. Six circumferential welds on the ECCS suction piping (3/train) in the pipe tunnel were scheduled for inspection during the Cycle 11 Refueling Outage. Of the three circumferential welds inspected on Train A, one weld had a rejectable indication which was successfully removed by buffing. Following train swap, three circumferential welds were then inspected on Train B. Allthree welds had multiple rejectable indications; of the total 9 indications, 8 were removed by buffing and one was repaired. Based on these results, Engineering required expansion of the inspection sample to include the remaining four welds in the Train B piping within the trench. Three out of four of these welds had rejectable indications. Of the total 8 indications, 6 were removed by buffing and 2 indications were repaired. Based on these results, FPL management also decided to inspect a sample of the ECCS piping for external orrosion deposits pursuant to CR 98-0047. Supplement 2 to CR 98-0047 identified two 5-foot sections of straight piping on I-24"-CS-2 (B Train) exhibiting the worst visual corrosion appearance be added to the inspection scope. Three areas within each of the 5-foot sections of straight pipe were selected to represent the worst corrosion attack. Allidentified indications within these areas were buffed out.
Purpose:
The purpose of this evaluation is to review the overall condition of the ECCS suction piping located in the piping tunnel just downstream of the Refueling Water Tank (RWT) to demonstrate it will meet its design requirements during operation until the Cycle 12 Refueling Outage. Scope: The scope of the evaluation is principally the 24" diameter Unit 2 ECCS suction piping between the RWT and the RAB contained, within the underground trench. The evaluation also identifies other safety related underground piping in the same trenches. Resolution of these specific lines willbe addressed in CR 98-1944. Stainless steel piping in other plant trenches willbe addressed as a followup action for the specific ECCS repair CR's. Revision 1 was issued to incorporate the verified APTECH analysis. Revision 2 was issued to incorporate changes made by Aptech to their calculation inputs and to bound the piping support modifications resulting from CR 99-0445.
PSL-ENG-SEMS-98-102 Rev 2 Page 4 of 15 II. EVALUATION si n Re uirements: The subject Refueling Water Tank (RWT) suction piping provides a flow path from the RWT to the Emergency Core Cooling System pumps for use during the Injection Phase following a Design Basis Accident. This function is safety related and is addressed in the plant's FSAR and Technical Specifications. FSAR As discussed in FSAR Section 6.3.2.2.4, the RWT is an atmospheric tank containing water borated between 1720 and 2100 ppm. Redundant lines are provided from a single nozzle on the tank to provide suction to the A and 8 Trains of Emergency Core Cooling System Pumps located in the RAB. The suction lines are routed to the RAB in a below grade trench which is open to the atmosphere. Technical Specifications Per T.S. 3.5.2 in Modes 1, 2, and 3 (with pressurizer pressure greater than or equal to 1750 psia) two independent ECCS subsystems shall be OPERABLE with independent flow paths capable of taking suction from the RWT. Per T.S. 3.5.3, in Mode 3 (with pressurizer pressure less than 1750 psia) and Mode 4, a minimum of one ECCS subsystem shall be OPERABLE with a flow path to the RWT. er T.S. 3.1.2.1 in Modes 5 and 6, a minimum of one boron injection flow path shall be OPERABLE which includes flow path from the RWT via either a charging pump or a HPSI pump, meeting the requirement in T.S. 3.1.2.7b ifonly the RWT flow path is OPERABLE. Design Basis The RWT Suction lines must be able to pass design flow at a design pressure of 60 psig and a design temperature of 300F to the ECCS pumps, have'the ability to maintain the pressure boundary and the RAB integrity. Operating pressures are defined by the column of water within the RWT tank and operating temperatures are defined by atmospheric conditions. As detailed within the Total Equipment Database and plant drawings, Lines I-24"-CS-3 (Train A) and I-24"-CS-2 (Train B) are connected to a single nozzle on the RWT and provide suction for the ECCS systems. The piping design pressure is 60 psig at 300F, with an operating pressure of 30 psig at 120F. The pipe is 24" schedule 10 (wall thickness of 0.250") in accordance with Ebasco Pipe Code SS-5. Lines l-24"-CS-2 and -3 are designed in accordance with ASME Section III, Class 2 requirements and are constructed ofASTM A-358, Class 1, Type 304 material. Unit 2 is currently in the Second Ten Year ln-Service Inspection (ISI) Interval. The code of record for Rules for In-Service Inspection in this interval is ASME Section Xf 1989. Safety Classification: This evaluation is classified as Safety Related as the Containment Spray and Safety Injection systems perform essential functions to mitigate the effects of a Design Basis Accident.
PSI.-EN(3-Si Mb-Jii-'iVd Rev 2 Page 5 of 15 Se uence of Discove /Examination Events: ceding Activities STAR 960294 identified stress corrosion cracking (SCC) concerns with regard to welds in the Unit 1 ECCS suction piping located in the trench between the RWT and RAB. The STAR identified SCC within a weld in line 24"-CS-3 which resulted in a weeping through-wall leak. As part of the STAR's corrective actions, all remaining horizontal circumferential welds were inspected in Unit 1 and PMAI 96-11-222 was issued to inspect a sample of welds on the Unit 2 ECCS suction piping (3 welds/train) during the 1998 Cycle 11 Refueling Outage. In a related issue, CR 98-0047 was written on 1/7/98 to address external corrosion deposits identified on top quadrant of Unit 2 ECCS suction piping located in the outside pipe tunnel. This CR's corrective actions included Work Order 98002077 which was generated to: 1. Clean 24"-CS-2 8 3 of corrosion products 2. Pressure wash the piping with demineralized water 3. Perform a visual (VT) and liquid penetrant (PT) inspection of suspect pit areas on piping sections 4. Perform a visual (VT) and liquid penetrant (PT) inspection of 6 circumferential welds 5. Application of a non-leachable chloride protective coatings Unit 2 Outage Activities f the three circumferential welds inspected on Train A, one weld had a rejectable indication which was uccessfully removed by buffing. No further inspections were made on Train A. Following train swap, three circumferential welds were then inspected on Train B. Allthree of these welds had multiple rejectabte indications. Of the total 9 indications, 8 were removed by buffing and 1 was repaired through the installation of a branch connection per PCM 98135. Based on these results, Engineering required expansion of the inspection sample to include the remaining four welds in the horizontal run of Train B piping within the RWT-RAB trench. Three out of f f the welds had rejectable indications. Of the total 8 indications, 6 were removed by buffing and two M 8135. indications were repaired through weld repairs and the installation of a branch connection under PCM 9 Based on these inspection results and the outage's mobilization of inspection and maintenance forces, FPL management rescheduled the inspection of a portion of the ECCS piping for external corrosion deposits (WO 98002077) to the Cycle 11 Outage window. Supplement 2 to CR 98-0047 identified two 5-foot sections of straight i in on 1-24"-CS-2 (B Train) exhibiting the worst visual corrosion appearance to be added to the inspection scope. Three areas within each of the 5-foot sections of straight pipe were selected to represent the worst corrosion attack. Allidentified indications within these areas were buffed out. A summary of all the inspections made to date and their results is provided in Table 1.
Wold¹ Train Condition Report Initial Initial After Rework Repair Basollno Final Ro]ect Character Rowork Character Document Wall Wall (inches) {inches) PSL-ENG-SEMS-98-102 Rev 2 Page 6 of 15 Table 1: Summary of Unit 2 ECCS Weld indications and Pipe Wall Corrosion Cells Excavation Aroa {inches) S-3-FW-904 None CS-3-3-SW-1 CR 98-1821 CS-3-FW-8 None None ¹1 Round Accept None 0.258 0.196 Not Available B Train CS-2-FW-901 CS-2-FW-3 CS-2-3.SW-1 Cs-2-6-SW-3 CS-2-FW-2 CS-2-FW-4 Cs-2-4-SW-1 CR 98-1879 ¹1 <<5 ¹6 ¹7 CR 98-1878 ¹21 ¹22 ¹23 CR 98-1877 ¹6 ¹16 None None CR 98-1897 ¹10 CR 98-1898 ¹2 ¹8 ¹12 CR 98-1906 ¹11 ¹13 ¹14 ¹15 See Note 4 Area 1, ¹1 Area 1, ¹2 Area 2 Area 3, <<2 Area 3, ¹3 Area 3, ¹4 Area 3, ¹5 Area 3, ¹6 Area 3, ¹7 Three Sample Areas on 5 foot B Train pipe section within East/West Trench See Note 4 Area 4, ¹1 Area 4, ¹2 Area 4, ¹3 Area 5, ¹1 Area 5, ¹2 Area 6, ¹1 Area 6, ¹2 NF = Not Found CR 98.0047 Supplement 2 Three Sample CR 98-0047 Areas on 5 foot Supplement 2 B Train pipe section within North/South Trench Round Linear Linear Linear Round Linear Round Round Round Round Round Linear Round Round Round Round Linear Linear Round None Round Round Linear Linear Round Linear Linear Linear Round Round Round Linear Round Accept Accept Accept Accept Accept Accept REJECT Accept Accept Accept Accept (1) REJECT REJECT Accept Accept Accept (1) Accept (1) Accept Accept Accept Accept Accept Accept Accept Acce t Accept Accept Accept Accept Accept Accept Accept Linear Linear Linear PCM 98135 CRN.8233 CRN-8233 0.289 0.271 0.259 0.241 0.261 0.241 0.265 0.249 0.262 0.234 0.262 0.234 0.282 0.1 0.428 0.403 0.375 0.308 0.259 0,25 NF 0.272 NF 0.083 NF 0.109 0.275 >0.235 0.275 >0.235 0.275 >0.235 0.275 0.235 0.283 >0.261 0.282 >0.261 0.28 >0.245 0.281 0,245 0.281 >0.245 0.28 >0.245 0.28 >0.245 0.281 >0.245 0.271 0.217 0.271 >0.217 0.271 >0.217 0.27 0.261 0.273 >0.261 0.266 0.218 0.266 >0.218 0.5 x 1.7 0.3 x 1.6 0.7 x 1.8 1.0 x 2.1 2.7 x 1.2 Note 2 1.5 x 1.5 0.75 x 0.3 1.0 x 0.3 1.0 x 0.7 1.7 x 0.9 1.0 x 1.8 2.25 x 1.8 1.25 x 1.0 0.75 x 1.0 1.0 x 1.25 1.25 x 1.75 1.35 x 1.10 1.27 x 2.63 1.25 x 1.25 1.0 x 1.0 1.5 x 1.5 1.6 x 1.6 1.0 x 1.0 1.0 x 2.15 1.0 x 1.0 1.3 x 1.0 1.0 x 1.0 1.0 x 1.0 1.0x 1.0 2.3 x 1 Note 5 Notes:
- 1. Omission of Indication from the re-examination Liquid
- 2. Excavation area]oined to ¹21 3,
Initial inspection scope on Unit 2 4. See Table 2 for description of pipe areas. 5. Excavation area oined to ¹1. "I ) Penetrant Examination Data Sheet indicates Accept Selection of lns ection Areas: Welds Augmented inspections were performed on the Unit 2 ECCS piping's horizontal field welds since previous leakage on Unit 1 was associated with a circumferential field weld on a horizontal run. The failure analysis performed on the Unit 1 flaw (STAR 960294) concluded that the leakage was the result of OD initiated stress corrosion cracking, associated with stresses from the field weld (and possibly a repair) and the presence of an external contaminant t attributed to the presence of chlorides.
PSL-ENG-SEMS-98-102 Rev 2 Page 7 of 15 Inspections were initiallytargeted to address piping field welds since the 24" piping is manufactured to A-358 Type 304SS, which receives a 1900'F stress relieving solution anneal after forming of the pipe and welding of the axial earn. As regions of increased stress (necessary to promote stress corrosion cracking) would be associated with field welds, the areas selected for initial inspection consisted of three circumferential welds. Of the three circumferential welds inspected on Train A, one weld had a rejectable indication which was successfully removed by buffing. No further inspections were made on Train A. Following train swap, three circumferential welds were then inspected on Train B. Allthree of these welds had multiple rejectable indications with one being repaired through the installation of a branch connection per PCM 98135. Due to the rejectable PT indication found on these B Train field welds which could not be removed, Engineering required expansion of the inspection sample to include the remaining four welds in the horizontal run of Train B piping within the RWT-RAB trench. Attachment 3, Figures 1 8 2 shows the locations of the inspected welds. Piping Due to the Train Swap to Train B, the piping section inspections for pitting corrosion centered on the B Train. Although this decision was timing based, this approach was consistent with the visual comparison between the A and B Trains which showed that the B Train appeared to have a greater buildup of corrosion products at the corrosion cells. Both pipes have multiple round corrosion cells or pitting (<3/8" in diameter) which are concentrated within the upper 120 of the pipe's horizontal run. It was noted that corrosion appears to be greater near the man hole cover over the East-West trench which is offcentered over the B Train piping: the manhole may be a source of water run offcontamination. Concentration of corrosion in this area is presumed to be the result of falling debris, dirt buildup, or contaminants. It is not clear whether the presence of a degraded Thermalox coating system on the Train is contributing to the corrosion by trapping contaminants against the pipe wall. To select a representative inspection sample of the external corrosion deposits on the Unit 2 B Train ECCS suction line, Engineering visually inspected the entire section of ECCS suction piping in the piping tunnel. Two 5-foot sections were initiallyselected for further inspection. Within these sections of piping, six regions were subsequently identified (3/section) and prepared for PT examination. The areas were chosen on the horizontal runs of I-24-CS-2 in the North/South tunnel and the East/West tunnel. Attachment 3, Figure 3 shows the locations of the six external corrosion regions identified for PT. The piping region with the most severe indications was confined to the area approximately 12" either side of top dead center (TDC). The bottom half of the pipe on both pipe runs was relatively free of corrosion cells compared to the top region of each section. Two regions in each run were selected from the most severe corrosion indication in the rolled plate and one region in each section was chosen on the axial shop weld. The regions selected were judged to be either representative of the other corrosion cells or had the most severe appearance based on pitting or corrosion buildup. Although the selected regions were selected to include axial shop welds, elevated stresses at these locations were not expected since the pipe fabrication specification (A-358 Class 1) requires a 1900'F anneal as part of the fabrication of the rolled and seam welded pipe. The areas on each section in the pipe trench are identified in Table 2.
PSL-ENG-SEMS-98-102 Rev 2 Page 8 of 15 Table 2: Summary of Sample Areas for External Corrosion Deposits Sample Area Location Description of Sample Area External Corrosion Deposit Sample Areas in the North/South Pipe Run 2"x2" area at 11:00, -6'pstream from support SI-2407-17 (8 welded lugs). 2"x4" area at 3:00 on the axial weld, -3'pstream from support SI-2407-17 (8 welded lugs). 2"x2" area at 12:00, -5'ownstream from support Sl-2407-17 (8 welded lugs). External Corrosion Deposit Sample A Contained 4 corrosion cells with one having visible pits. Contained 4 corrosions cells on the weld and 5 above the weld on the plate. Area of darkest stain with no visible depth to pits. Contained a large corrosion cell with a cluster of visible pits. reas in the East/West Pipe Run 1 "x6" area at 12:00, -6'pstream from weld CS FW-4. 1 "x5" area at 11:30 on the axial weld seam, -4'pstream from weld CS-2-FW-4. 1 "x3" area at 10:00, -3.5'pstream from weld CS FW-4. Contained 3 corrosion cells with large clusters of visible pits. Contained 6 corrosion cells with clusters of visible pits. Contained 4 corrosion cells with a thick build up of corrosion deposit under the Thermalox 70 coatin Failure Mechanism: The Figure below is a photomicrograph illustrating preliminary results of a metallographic examination performed on a sample removed from Unit 2 Line l-24"-CS-2 in the region of Weld CS-2-FW-3. The highly branched, O.D. initiated, through-wall crack is typical of chloride induced stress corrosion cracking. Further metallographic analyses willbe performed to evaluate the proximity of the crack to the weld and HAZ, and to determine ifthe base material is sensitized. The base material is specified as A-358, Class 1, Type 304 SS. Photomicrograph of Section taken at Weld CS-2-FW-3 on Line l-24"-CS-2 The mechanism is typical of chloride induced OD stress corrosion cracking (ODSCC). This mechanism is identical to that previously identified in the root cause analysis associated with STAR 960294 (PMAI 96-03-249). With any SCC mechanism, there are three requirements for cracking to occur: 1) A susceptible material, 2) A tensile stress; nd, 3) An environment with a contaminant (for example, the chloride in salt air). Although chloride SCC does not typically occur at temperatures below 140'F, an elevated stress condition can lower this temperature "threshold".
PSL-ENG-SEMS-98-102 Rev2Page 9of15 This may explain why indications at the field welds are severe by comparison to those in the rolled and axial welded pipe that was solution annealed. ction XI Considerations: IJnit 2 is currently in the Second Ten Year In-Service Inspection (ISI) Interval and the code of record for Rules for In-Service Inspection in this interval is ASME Section XI 1989. Since the subject piping is Class 2, the rules of Article IWC apply. The flaws and indications described above were identified during inspections of sample areas conducted in accordance with corrective actions from STAR 960294 and CR 98-0047. While the flaws and indications were not identified during a scheduled ASME Section XI inspection, the rules for examination and repairs/ replacements apply since the subject piping is Safety Related and within the jurisdiction of the ASME code. Article IWC-3120 provides acceptance and evaluation criteria for surface or volumetric examinations. There are four primary methods of acceptance which include Examination, Repair, Replacement, or Evaluation: ~ IWC-3122.1 Acce tance b Examination "Components whose examination reconfirms the absence of flaws, reveals flaws that do not exceed the acceptance standards listed in Table IWC-3410-1, or reveals flaws that are acceptable in accordance with IWC-3121(b) shall be acceptable for continued ser vice. ~ IWC-3122.2 Acce tance b Re air "Components whose examination reveals flaws that exceed the acceptance standards listed in Table IWC-3410-1 shall be unacceptable for continued service until additional examination requirements of IWC-2430 are satisfied, and the flaw shall be either removed by mechanical methods or the component repaired to the extent necessary to meet the acceptance standards of IWC-3000 ~ IWC-3122.3 Acce tance b Re lacement "As an alternative to the replacement requirement of IWC-3122.2, a component or the portion of the component containing the flaw shall be replaced. ~ IWC-3122 4Acce tance b Evaluation " (a) Components whose examination reveals flaws that exceed the acceptance standards listed in Table IWC-32410-1 shall be acceptable for service without the flaw removal, repair, or replacement ifan evaluation analysis, as described in IWC-3600, meets the acceptance criteria of IWC-3600. " (b) Where the acceptance criteria of IWC-3600 are satisfied, the area containing the flaw shall be subsequently reexamined in accordance with IWC-2420 (b) and (c) Penetrant inspections performed on ten welds within the 24"-CS-2 and 24"-CS-3 piping identified 18 indications outside the acceptance criteria of IWC-3122.2. As indicated by Table 2, 15 of the rejectable indications were successfully buffed out without violating minimum wall requirements. At two weld locations, 3 indications could not be removed in this manner as the size of the indications exceeded IWC-3122.2 acceptance criteria. In order to eliminate these remaining indications, the following repairs were performed.
PSL-ENG-SEMS-98-102 Rev 2 Page 10 of 15 Table 3: Summary of Weld Repairs on ECCS Lines Weld cation Repair Methodology Code Acceptance CS-2-FW-3 CS-2-FW-4 Indication ¹23 was removed by drilling a hole>>4 inches in diameter. Edges of machined surface were PT inspected and a branch connection installed IWC-3122.3 in accordance with PCM 98135. Indication ¹12 was removed by drilling a hole -4 inches in diameter. Edges of machined surface were PT inspected and a branch connection installed IWC-3122.3 in accordance with PCM 98135 (CRN-8233) Indication ¹8 was removed by excavation/weld repair. Branch connection allowed access to the backside of the weld for purging and finish grinding. IWC-3122.2 Final surfaces were PT inspected. See PCM 98135 {CRN-8233) While all of the identified weld flaws were repaired as indicated within Table 3, Section Xl does allow Acceptance by Evaluation (IWC-3122.4). An acceptance by evaluation approach was pursued in parallel with the development of the above repair methodologies. This effort was pursued to address the remote potential that a repair modification would not be physically possible, or that the need for a repair was identified late in the outage schedule or that a large number of small flaws were identified which would preclude a short-term cost-effective repair approach. In anticipation of the possibility of adverse inspection results, Engineering elected to perform the additional evaluations in parallel with the on-going examinations and rework methodologies. As the Section XI Code rules specified within Section IWC-3600 were under development in the 1989 code, the guidance contained within IWB-3600 was utilized. This activity is discussed in the next section. tructural Inte ri Review: Preliminary results of flaw sizes were forwarded to APTECH Engineering Services for their assistance in evaluating a leak-before-break approach. This entails identifying the critical flaw size that would be unstable for the design conditions of the piping node with the highest stress. Analysis methods in ASME Section Xl under Paragraph IWB-3640 and Appendix C were used to compute the allowable through-wall flaw length and predicted growth as a function of operating time. Growth by SCC and fatigue mechanisms were considered in the flaw growth assessment. This preliminary analysis was performed using the following inputs: ~ Design Conditions of 60 psig and 300F for a 24" nominal pipe size Schedule 10 constructed of 304 SS ~ Maximum membrane and bending stresses were identified from the piping stress analysis for the nodes of the ECCS A and B Train piping contained within the trenches. Maximum values for each equation were selected to bound all nodes. {See Attachment 2) ~ Assumed maximum flaw length of 1.35 inches based on preliminary field inspection results. For the preliminary analysis, the allowable through-wall flaw size was determined for normal/upset conditions with a Section XI Code safety factor of 2.77 for circumferential flaws and 3.0 for axial flaws. The allowable circumferential flaw length was computed to be -26 inches and the allowable axial flaw length was computed to be -12 inches. Both of these structural limits are far greater than the surface indications observed during the inspection and repair of the affected piping. For the final analysis, the maximum initial flaw length to be used in the calculation was determined to be 1.18, based on actual recorded indications. The allowable circumferential flaw length was computed to be32.2 inches ) and the allowable axial flaw length was computed to be 13.6 inches. Both of these structural limits are far greater
PSL-ENG-SEMS-98-102 Rev 2 Page 11 of 15 than the surface indications observed during the inspection and repair of the affected piping. The above analysis demonstrates that the ECCS piping would leak-before-break, thereby providing sufficient arning of crack propagation long before any imminent failure. For the maximum stresses,a through-wall rcumferential flaw of 32.2 inches (13.6 inches for an axial flaw) would satisfy the minimum safety factors. A conservative flaw growth evaluation indicates that adequate safety margins will be maintained for at least one cycle of operation. It is concluded that the structural integrity of the piping is adequate for all design loads per ASME Section XI. Additionally, leak detection by periodic walkdown shall be maintained in the areas affected by corrosion degradation. This analysis approach is considered conservative as this system is normally in a standby mode with atmospheric tank pressure head on the system (-30 psi vs. 60 psig design) and operating at environmental temperatures (<100 'F vs. 300'F design). Additionally the piping is not subject to any of the following: vibratory loading, periodic pump starts and stops (cyclic loading), thermal cyclic loading, wind loadings, etc. Based on evaluation of the identified flaws and the analysis of critical crack size, Engineering concludes that monthly visual surveillances of the ECCS suction lines for leaks would be adequate to provide leak-before-break detection. The above APTECH evaluation is final andhas been checked and verified in a formal calculation under APTECH's Quality Assurance Program. The results of the flinal analysis do not change the conclusions of the Safety Evaluation. Conse uences of Accidental Leaka e: The above evaluation has determined that the Unit 2 ECCS suction piping is acceptable to operate until the Cycle 2 refueling outage. However, in the unlikely event that a leak does develop in the ECCS suction piping, an additional evaluation was done to show the radiological consequences would be bounded by the radiological consequences of the accident analysis of record. The following discussion presents arguments why a single point leak is bounded by the loss of a complete train of the ECCS or LPSI pump. To conform to the requirements of 10CFR 50.46(b) and part 50, Appendix K, Item D.1, Post-Blowdown Phenomena; Heat Removal by the ECCS Single Failure Criterion, analyses of Loss of Coolant Accidents (LOCA) at St. Lucie Unit 2 typically assume that either one complete train of ECCS (for small break analyses) or one LPSI pump is unavailable to provide injection (and subsequent recirculation) flow to the core. These assumptions are utilized because break spectrum and historical analyses applicable to St. Lucie have demonstrated that these particular failures maximize the fuel cladding temperature and produce the limiting site boundary dose values. Of course, a variety of other single failures involving both active and passive components can be postulated to occur during any LOCA event. As an example, check valve V07174 which separates the RWT makeup piping from the containment sump recirculation line in the A ECCS train (Ref. 5) can be postulated to fail to remain closed to the environment during the post-injection phase of a LOCA, potentially leading to the release of liquid effluent and radionuclides to the local environment. However, an assumption that this failed valve constitutes a viable single failure would preclude consideration of an ECCS train or a LPSI pump as inoperable during the injection phase of the event. The availability of a second train of ECCS or a second LPSI pump to provide core makeup during the injection phase of the LOCA reduces both the extent and duration of core uncovery, thereby reducing the calculated fuel rod adiabatic heatup and the exothermic zirconium-steam reaction. This reduced fuel rod heatup ubstantially lessens the resulting fuel damage and fission product release as compared to the case where one train of ECCS or one LPSI pump is unavailable. As a result, a LOCA event scenario that assumes failure of a
PSL-ENG-SEMS-98-102 Rev 2Page12of15 injection train check valve to remain closed during the recirculation phase of the event willyield a more benign site boundary dose than that resulting from a loss of ECCS injection capability such as is assumed in the St. Lucie 2 alyses of record. eview of Other Lines Located in ECCS Pi in Trench: Based on the identified degradation of the ECCS piping within the East-West and North-South trenches a review was made of the other piping within these trenches for susceptibility to ODSCC. Piping within these trenches, as summarized within Table 4, was identified by inspection of plant layout drawings. Of interest forthis review were lines with a safety related function that are constructed of stainless steel. Table 4: Summary of Piping Contained Within ECCS Pipe Trench Piping Located in,th', EastlWest ECCS.'Pipe',Trench,':'l",.'l North Side South Side Line Number CL I-20"-CC-17 I-20'-CC-27 I-24"-CS-3 4"-PMW-6 3"-DWS-14 3"-FS-556 T pe Service CS Suppl Loop 8 CS Return Loop 8 SS RWT To ECCS A SS PMW to RAB SS DMWfrom U-1 SS FP lon Ex to RWT Line Number I-20 -CC-16 I-20 -CC-26 1-24"-CS-2 I-3"-CH-938 6"-CS-500 3"-WM-A29 CL Type 3 CS 3 CS 2 SS 2 SS N SS N SS Service Suppl LoopA Return Loop A RWTTo ECCS B BA to RWT Sl 8 CS Pump Recirc WM to CW Disch Piping Located iri the.North/South-ECCS Pipe ~Trench ".:.-. ':,...;. North Side South Side Line Number CL Type Service Line Number CL T pe Service I-20 -CC-16 1-20"-CC-17 -20"-CC-26 20"-CC-27 I-30 -CW-78 I-30"-CW-79 2"-DWS-6 3"-DWS-14 3 -FS-513 3"-FS-556 4"-PMW-6 3"-PMW-16 3"-WM-A29 3 CS Suppl Loop A 3 CS Suppl Loop 8 3 CS Return Loop A 3 CS Return Loop 8 3 CS CCW Hx 2A Inlet 3 CS CCW Hx 28 Inlet N SS DMWto DGB N SS DMWfrom U-1 N SS RWT to FPP Pump N SS FP lon Ex to RWT N SS PMW to RAB N SS PMW to RWT N SS WM to CW Disch. 1-24"-CS-2 I-24"-CS-3 I-30 -CW-78 I-30"-CW-79 l-30"-CW-90 I-30"-CW-91 I-3"-CH-938 6"-CS-500, SS RWT To ECCS 8 SS RWT To ECCS A CS CCW Hx 2A inlet CS CCW Hx 28 Inlet CS ICWto CCWHx2A CS ICWto CCW Hx 28 SS BA to RWT SS Sl 8 CS Pump Recirc. Review of Table 4 indicates the only safety related lines constructed of stainless steel are the ECCS Suction Lines (24"-CS-2 and 24"-CS-3) and line to supply boric acid to the RWT (3"-CH-938). The 3" boric acid supply line is constructed of Schedule 10 per SA-312 Type 304. Walkdown of this line is warranted based on the inspection of the ECCS piping. A preliminary visual inspection of this piping by Engineering shows a significant number of corrosion cells on this pipe in the ECCS tunnel. This condition is being addressed by CR 98-1944. Interaction of other non-safety related stainless steel lines in the trench willalso be addressed in this CR. Review of Lines in Other Plant Pi in Trenches: Based on the identified degradation of the ECCS piping within the ECCS trenches a review was made of the piping within other trenches for susceptibility to ODSCC. This review will be completed as a followup activity in CR 98-1898.
0
Future Periodic Field lns ections / Walkdowns: PSL-ENG-SEMS-98-102 Rev 2 Page 13 of 15 ased on the discussions above, the identified root cause is attributed to the presence of chlorides that attach the outside surface of the piping. This is corroborated by the fact that the inspections done on piping outside r the trench that is exposed to the atmosphere and rainwater had far fewer indications (removable) than the piping within the trench. Rinsing off the piping on a regular interval would provide additional life to the piping. This should be accomplished by a light duty pressure washer such as a 1500 PSI unit. Larger units can be used, however, it is intent to not disturb any coatings on existing piping / pipe supports, or structural components. Accordingly, a Mandatory Preventative Maintenance (PM) activity to periodically pressure wash the piping has been initiated. The request has been submitted in accordance with Plant Procedure AP-0010431 and a PMAI initiated to Planning to ensure issuance of a PWO and initiation of planning activities. Based on the evaluations above, the fracture mechanics evaluations demonstrate that, with the low stresses, the identified flaws are acceptable for at least another cycle. The analyses also demonstrate that the piping would "leak-before-break" (LBB), thereby providing sufficient warning of crack propagation long before any imminent failure. In order to ensure the validity of the analysis, periodic monitoring will be implemented to inspect the piping for leakage. This will be accomplished via the PM discussed above and will be done prior to the periodic cleaning. The PM willbe accomplished once per month until the piping is coated. Based on walkdowns of the trench and piping, two observations were made: first is that the worst pitting appears to be in the middle section of the east west trench, and secondly, with the trench manway cover off, rainwater collects on the pavement and flows into the manway. Although the manway is normally in place, it does not provide a water tight seal. When it rains, some water could be entering through the manway and splash down over the various piping systems within the trench. Based on discussions with the FPL metallurgists, the presence of chlorides in the water together with the low flow (leakage through manway only) could be depositing chlorides on the piping surface as well. In order to eliminate this potential source, one of he corrective actions below is for services to install a drip pocket underneath the manway with a tygon hose own to the floor. This willdirect the water to the floor and ultimately to be removed by the sump pump. Actions need to be considered for long term condition of the piping. The actions may include recoating and/or piping replacement. In addition, the remaining welds in the A train piping should be inspected during the Cycle 12 refueling outage. Finally other stainless steel lines enclosed in trenches should be reviewed for this same condition. III. CONCLUSION This evaluation demonstrates that the St. Lucie Unit 2 ECCS suction lines are capable of performing their design function considering the corrosion attack identified and repaired during the Cycle 11 refueling outage. The piping has been evaluated to meet its design loading considering crack growth durations through the Cycle 11 operating cycle. IV. PLANT RESTRICTIONS Plant operation is justified for one operating cycle until the Cycle 12 Refueling Outage. This evaluation willrequire revision to allow further operation beyond the Cycle 12 Refueling Outage. I
V. ACTIONS REQUIRED PSL-ENG-SEMS-98-102 Rev 2 Page 14 of15 These corrective actions have been assigned PMAI's per CR 98-1898: Implement actions to minimize water entering the trench and contacting the enclosed piping. Implement a PM for monthly inspections of CS-2 and CS-3 in the piping trench for through-wall leakage and pressure washing of the stainless steel piping in the trench. 3. Develop a long term plan for this piping (i.e. pipe recoating, replacement, etc.) Perform 100% inspection of remaining circumferential welds within the Unit 2 A Train ECCS suction piping located in the horizontal runs within the East-West and North-South trenches during the Cycle 12 outage. Update this evaluation to address operation of St. Lucie Unit 2 beyond Cycle 11. Address other safety related, stainless steel lines in other trenches in both Unit 1 and Unit 2. The Unit 1 ECCS piping should be included during this review. VI. REFERENCES 1. St. Lucie Unit 2 FSAR, Amendment 11 2. St. Lucie Unit 2 Technical Specifications, Amendment 98 3. REG Guide 91-18, Rev 1 Drawing 2998-G-088 Sheet 2, Rev. 29 Drawing 2998-G-125 Sheet CS-K-2, Rev. 18 6. Drawing 2998-G-125 Sheet CS-K-3, Rev. 21 7. Drawing 2998-G-172, Rev. 14 8. Drawing 2998-G-173, Rev. 19 9. CR 98-1821
- 10. CR 98-1877
- 11. CR 98-1878
- 12. CR 98-1879
- 13. CR 98-1897
- 14. CR 98-1898
- 15. CR 98-1906
- 16. STAR 1-960294
- 17. PMAI 96-03-249
- 18. CR 98-0047
- 19. Calculations PSL-1FSM-98-002, Rev 0 8 PSL-2FSM-98-012, Rev 0
- 20. APTECH Engineering Services Letter dated November 25, 1998
- 21. APTECH Engineering Services Letter dated December 1, 1998
- 22. APTECH Engineering Services Letter dated April 7, 1999
VII.VERFICATION
SUMMARY
PSL-ENG-SEMS-98-102 Rev 2 Page 15 of 15 ethod of Verification e SDC System Design Bases were reviewed to ensure that the system design was properly evaluated gainst applicable FSAR, NRC Regulatory Guides, and 10 CFR Part 50 requirements. The Plant Technical Specifications were reviewed to ensure that no change to the Plant Technical Specifications was required. Referenced inputs and guidance documents were reviewed to ensure that the information incorporated w'as properly utilized and documented. The safety classification (Safety Related) has been correctly chosen and adequately addressed in this Engineering Evaluation. Conclusions Assumptions required to assess the acceptability of the ECCS system considering the condition of the piping were adequately described and reasonable. Design inputs were correctly selected and incorporated in the APTECH calculations which were then correctly translated into the conclusions of the evaluation. Drawings and manuals used in this modiTication were checked to ensure that the latest revisions were utilized. Interface requirements were demonstrated to be satisfied. The evaluation has been properly documented and correctly concludes that the ECCS system will continue to meet its design requirements as a result of this condition and no change to the Technical Specifications is required. he conclusions provided by this evaluation are reasonable when compared to the inputs. The acceptance riteria for the design was adequately documented to allow verification that the design requirements have been satisfactorily accomplished. VIII. ATTACHMENTS 1. APTECH Engineering Services Letter dated November 25, 1998, Preliminary Flaw Evaluation of Corrosion Degradation ofECC Suction Piping in St. Lucie Unit 2, rev. 0. 2. Stress Analysis review of maximum stresses for CS-2 and CS-3 within the trench, rev. 1. 3. Sketches of ECCS piping, inspected welds and piping in the trench, rev. 0. 4. APTECH Engineering Services Letter dated April 7, 1999 Evaluation of Corrosion Degradation of24" ECCS Piping at St. Lucie Unit 2, rev. 2.
tS APPLIEDTECHNPl.QGY PsL-Eo~-Mn~-98-l<< R,c i4ovember 25. l 99S Py I oc:P Flonda Power E L)iht Compan> St. Lucie Plant 6501 S. Ocean Drive Jensen Beach, Florida i495 7 Attention: iblr. 4itike 4!oran
Dear Sir:
RE: Pre.iminary Flaw Evaluation or Corrosion De ~radatio: of ECCS Suction Piping in St. Lucie. tJni: 2 ~Ve have completed a preliminary analysis nfthc strt(c(ural capacity ot the 24-inch suction piping containing outside surface corrosion. Thc analysis conservatively ass ines thc corrosion is con)prised ofpitting and cracking with the primary cracking n ech n:91n bein@. stress corrosion cracking (SCC). Both circumferenti'l and axial flaw orientations were evaluated. A leak-before-break approach was used to establish the largest acceptable flaw lcng;h f'r th pipe. Ana!ysis methods in ASME Section XI under Paragraph l4'8-~640 and Appc:Idix C were used to comoute thc allov able throuoh-wall flaw lengths and predicted fiaw grovah a>> a function OI operating time. Growth by SCC and fatigue mechanisms was con>>idercd in the fiaw 6 owth asscsstrlcnt. P3P} IKEORMAT30iM The piping is 24-inch nominal pipe size, Schedt)lc l0 wh re D = 2" inches and avail thickness, t=0.25inch. The pipe materia} is Type30" stainless s'eel. The de>>i n conditions are: p = 60 ps)g T ."100! The pipin~ system is designed to ASME Sec:ion 3I I, Class 2. APTECH ENGINEERING SERVICES, INC, 1282 REAhllVOODAVENuE 1' sUNNYvALE > 'AUFORNIA94089 (408) 745.7000: FAX (408) 73 "04451 '.MAIL;:ptec!isuSix.nelcom.coii1 HOUS ON, iX( (713) S. "- 00 'lrrSBUFGH, PA L (412) siC 88:."C A LAN A GA ~j (770) 78;.37:-; BErHL.EH"-l.LpA ~ (8'l0) 888-7&7)'I cHARLGl E, Nc ( 01) 8854318 -': rN=(.q,, 9:, a; <<-pIHINGTQN.DC~(301) 888-1".o ~ ~ c ' ~ ~ J ~ J
Florida Power 8'ight November 25, l 993 Page 2 P7L-E'g &-S-795-V-l02. Rilo g, l K<V o Pg. z, oV 3 PIPING STRESSES Thc maximummembraneandbe d' b nding stresses for tne ltne in areas af}'ected by cor osion ~ ~ ~ de@ adation were compiled by Florida Power 8.' tght (FPL) as dncun]cnted in Calculations PSL-l FSWf-98-002 and 2FSM-9S-012. These stresses arc: P DIV OBE DBE THER li95 psi 3056 psi 3022 psl 3900 psl n!t40 psi C hcse stress components yield the followinz service loading conditions use in tl;e St~reve foci formal/Uoset Emereqpcv!/'solaced l4-".0 6073 6962 Pc SS40 3NCO The primary membrane stress (Pm) is based on design prcssure. The primary bending stress is thc sum of'ead weight (DN) and seismic (Oi3E or DBE). The expansion stress ( e) is based on thermal and SAM loads, For evaluating axial flaws, the hoop stress is required. The hoop stress is calculated as twice Pm or 2880 psi. ALLO'BUYABLEFLA~V LD'GTH The allowable through-wall flaw size was de;ermired "or norm;l/upset co~" 'on-wi'n -. X~t Section Xl Code safety factor of2.77 for circumferential llaws and i.0 I'or axial flaws. The flow stress for t're pipe material w s assumed to be 4".2 } si. The allowable circumferential flaw lenyh is computed to bc approx'mately 26 inches. For axial oriented cracks, the allowable throuoh-wall flaw Icn"th i' 12' ., 8 'sa nut inc e>>. Both of'these structural limits are much greater than the surface indications observed durin ~ in and repair of'aftected piping. t ns o serve ur>n ~ inspection ~ ~ ~ ~ ~
Florida Power 8: Lieht november 25, I 993 Page ~ f'SL-CH&-sE~s gg>> Rli<. l Rcv. 0 3 o$ a FLA~tt'ROV,'THANALYSIS The gros,qh ofsurace f'v, flcv'5 will be limited to tn<e weld areas v herc local r -'d l ~ pip exterior is recoated to prevent furhcr environmeiital.'tack, the potential for furhe. SCC will bcsignit"- atiy ' -'.Il, fl ~ '<<c n iy re uceo. Ilowever, a fla.v growth eva uation v'as pe <ormcd assurnin<<SCC will be operative and flaws could contin" e to propa"=ate f<o<<m a<< 'xisti." ~n<y.-. >esurtac indicationslpittin<<. Based onaninitial tl-wl .2 sumcd t<<rough-wal!, the service period required to grow to the allow'able size exceeds'ars. i, 'i ' years. Initial flaw lengths closer to the maximum observed surtace (i.e.. = .>5 inches) v:ould have an acc ~table o~cratlonal pcrio o't~ ears t'
- i. ~
~ <<< i n<<pcrlo 0< a out 2 years. It is expected that lor<g deep tlaws w'll be detected by evidence ofboratcd water leakage becoming visible from the pipe. Std&IARYA~D COVCLUSIOUS A preliminary calculation divas completed to dctcrrnir<e the acc )table size of surface indications based on a leak-be fore-break strate ~'. AS~f2 < -'I l. ection XI llaw evaluation methods and acceptanc. crite. ia were used. For the s:resscs provided by FPLa throu~'h-wa aw of26 inches v ould d satisfy the miiiimum s-e'.y factors. A corservative tlaw growth evaluation indicates that adequate safety margins u:ill be maintained l'or at lcas: one cycle ofoperation. 1t is concluded that th-stoic' -l ' f' d iu t <ol all design lo;--: per AS WlE Section XI pl'ovided that 'ea' tc t i vi e. tnat 'ea oetcction is maintained in the areas atrected by corrosion d maraca:ion This evaluation is curr<ently being documcntcd (ch ck d - d -" d 'e ar v ritied) in a form l calculation under our Quality Assurance Proerain. 1f uh yo s ou!d have questions regarding these results, please do not hesitate to call. Sincerely, 0 g...g Russell C. Cipolla Project 5 fanau<er ~ I P ~ ~ ~ ~ i<'.v 7", 6'"'"
Prepared By:~ ~ v- ~ Verified By: MAXIMUMSTRESSES ( NOT INTENSIFIED)FOR SI PIPING INTHE PIPE TUNNELAREA A 8'c B TRAINS) 1,395 PSI 2,704 PSI PRESSURE DEADWEIGHT(D 1,580 PSI OBE INERTIA OBE 1,618 PSI DBE INERTIA(DBE 2,026 PSI P+DW STRESS COMBINATIONS P+ DW+ OBE P+ DW+DBE 4,099 PSI 5,717 PSI 6,125 PSI 1,580 PSI
References:
1) Stress Calculation 2412, Run 2, Rev. 8 (Train "A") 2) Stress Isometric SI-199-74, Rev. 8 g'rain "A") 3) Stress Calculation SI-2407AC, Rev. 0 (Train "B") 4) Stress Isometric SI-19941, Rev. 8 (Train "B")
RNT 2 f.L. 21'RENCl.l OPENiNG Pr rg+ ( )rrr L Q.. ~rr ~ ~rrr ~rr ~ 1%4 r )C 'L ~r ~ go ~ ~rr 8( Qr Wg>> C r+ ) C ' r ~ \\rr ~,s. AFFECTED AREA F'IGURE t ECCS S UCTlON P lP lNG
+ 4~g 4~ i-'Q( ooo 4 ppoo C' CZ-J C uO 4v 7v < L %$+J C'%J v J ll yr 4 op op 44pop oop pre ~QX Z~ J~lvl~ + INspccfcn lvcLn5 0< onicn lIccns FIGURE 2 ECCS SUCTION PIPING IN TRENCH 0$ Ã P1 8
t=!GURE ECCS SUCTION PIPING B TRAlN STRAlGHT PlPF lt l~p~l -7~>~~
Is'APPLIEDTECHNOLOGY 'I Mr. Carl Bible Florida Power 8t'ight Company St. Lucie Plant 6501 S. Ocean Drive Jensen Beach, FL 34957 April7, 1999 Psi -EZ( -S,&AS, -'t8-ION ATTACHMENT REV. pgop l oF~3 Attention: Mr. Mke Moran RE: Evaluation of Corrosion Degradation of24-Inch ECCS Piping at St. Lucie, Unit 2 (Ref. FPL P.O. 00034916, Rev. 4) (APZECH Project AES 98113566-1Q, Rev. 1)
Dear Sir:
We have completed Revision 1 to Calculation AES-C-3566-1 regarding the flaw evaluation for the ECCS supply piping at St. Lucie, Unit 2. The calculation was revised to incorporate new maximum stresses for the modified piping support arrangement. Enclosed is a controlled copy ofthe final calculation that documents the revised evaluation. In summary, a Qaw evaluation was performed to ASME Section XI,Appendix C, methods and acceptance criteria,. The allowable through-wall Qaw lengths and estimated Qaw growth during service were computed. %he conservative Qaw growth analysis indicates that adequate safety margins willbe mamtaincd for at least one cycle ofoperation. The 'tructural integrity ofthe piping is acceptable for the design-basis loading conditions based on leak-before-break. 'Therefore, Code safety margins vrillbe maintained in the areas affected by corrosion degradation when detectable through-wall leakage is expected to occur.'. I have also enclosed a document transmittal form. Kindlysign and return the form to the'ddress indicated on the form. RCC/sjh Enclosures Sincerely, I~ c'. p~ Russell G Cipolla Project Manager APTECH ENGINEERING SERVICES, INC. 1282 AEAMWOODAVENUES SUNNYVALEP CALIFORNIA94089 1C3566C2,DOC (408) 745.7000 E3 FAX (408) 7S44445 p EMAIL:eptechsuolanetcom.corn HOUSTON, TX0 (281) 55842000 PITTSBURGH, PAP (412) 9206633 P ATLANTA,GA0 P70) 7814756 BETHLEHEM,PAP (610) 866.7347 P CHARLOTTE, NC P (704) 865.6318 ieeceiveg gime" " )pi. y. p.4~pgsHINGTok,Dcp(301)&&4899
f'S L,- t= nh & - 5 &n S 'i 'E - i o2 CALCULATIONCOVER SHEET ATfACHMENT Calculation No.: AES-C-3566-1 Q Uncontrolled Controlled
Title:
Evaluation of Corrosion Degradation of 24-Inch ECCS Piping at St. Lucie, Unit 2 Horida Power Ec Light Company Project No.: AES 98113566-1Q APTECH Office: Sunnyvale Sheet No. Document Control No.: I-2 Purpos~: The purpose of this calculation is to determine the allowable through-wall flaw lengths and expected service lifeofECCS supply piping subject to corrosion on the outside surface. The allowable Qaw length is based on the acceptance criteria ofASMESection XI,IWB-3640 for all design loading conditions. Assumptions: Assumptions are given in Section 2.0. Results: Asummary ofresults is presented in Section 6.0. The structural integrity ofthe pipe is adequate for all design loads under leak-before-break conditions. Revision No. Prepared By Date l lgyB Checked By Date Vortrtod By '7 Af'R Approved By Date r<r pg Revision Description Initial Release Updated analysis for revised (unintensified) stress input for SI piping IRPTNN ENGIHEERlhQ SERVlCES, tNC. Received Time Apt. 7. 1:38PM QAN45 REV. 8196
~ ~ ~ ~ ~ ~ ~ gI Q ~ ~ ~ I ~ I I ~ ~ I ~ I ~ I ~ ~ ~ 0 ~ 0 ~ ~ ~
Calculation Vo.: Aos.c ~56o.[
Title:
Eva[ua'ion ot'Cot-,osion Ocg Radon o[I4-[IIch ECCS Pi[line. at St. Lucio, Unit ". S'I'c bv CI:ccI:cd. IFy: ~~( ttcvtI[CIIio.! Oo;c j/ys [ >ac. 99 OocvFocnt Cnntyo[ Yo [ 'I CalCIII; FPL.L Project Yo.: Al s 0$ [ [s56o'Q SIIcct YZ.: i ol'~ 1.0 liiTRODUCTtOYi Surfa-e indications were found on th" emergent core cooling system (ECCS) supply piping (l. ".), 'g he su;L ce indications tvere detected durh inspection and ar" tee result of pittino cracl;ing du;
- o sur ace corrosion.
Et is believed that the observ"d pitrinnjcracl< n" occt:rrcd over '.L.":!i.--. ",:- ".".- )lant. as the instated piping ls the orlgUlal mLaterial. Toe majority of thc indica:ions werc located in the neighborhood of welds and werc prizariiy czcunfcr ntiaUy oriented. The ECCS supply piping and fittings are faoricated hotn Type "=0! st=inlcss steel. Tlus alloy is knovz to bc susceptible to st.ess corrosion cracking (SCC). Of: the surface indications examined, most pitting!'cracks'ng was in the base metal near wclds, bu[. sotne was observed at thc weld. The prozirnitv of cracks to weids indicates that weld residual stress 's are contributing to thc cracL'qg. The purpose os this calculation is to'dctenPze the allowable flatv lengths and acceptabl-s."i'it e 1 2 of ECCS supolv pipin F contin~ thou h-wall cracks. A Ical'-b fore-break approach is fodtotved to verLy that the observed indications willnot significantly affect pipe integrity prior o leak detecrion. This calculation includes a critical flaw si=c evaluation to establish the allowabl 0=-tv len<<ch for the af.'ected piping. This calculation also includes a f'[aw growth analysis that quanti.'ies the growth r te of cracks over tirrc. This growtth analy'.:s is based on expect d crack propa ation mcchanislws of faL[gue crack grotvth (FCG) and SCC. The flaw evaluation rules provided in Appends C of American Societ'f iVfechanical Engineers (ASIA/E) Code S.ction XI (~) are used as guidance in completing this calculation. psL-Pl&-seals-9'E-lo"- PViACHh'EHl QAE1V R~ S/96 ~ ~ ~ f~ ~ F I+' ~ ~ ~ ~ s ~- I liI ~ I ~-u
~ ~ ~ ~ ~ ~ ~ I ~ ~ ~ ~ ~ ~ I ~ ~ ~ ~ ~ I ~ ~ Cl ~ ~ ~ 0 I l ~ 1 ~ 'C ~ ~ IS 4 0 ~ I ~ IS O ~ ~ ~ ~ ~ I I ~ ~ ~ ~ 0 ~ 0 ~ ~ ~ ~ ~ ~ ~ t ~ 0 ~ ~ l I s~ ~ ~ ~ t ~ ~ ~ ~ 4
I I I ~ ~ ~ ~ ~ ~ ~ l ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 4 ~ ~ ~ I I ~ ~ I I ~ ~ I ~ I ~ I ~ I ~ ~ ~ I ~ ~ I ~ ~ ~ ~ I \\ I ~ ~ I ' I ~ I I ~ ~ I ~ ~ ~- ~ s ~ ~ ~ I ~ ~ ~
Qlculntion >0.: A:.S-C-3566-1 Made bi ti/i/~8 Clic on FP8:I.
Title:
Fvzluztion ofCor;osion Dcg~Mon of 2-"-Inca LCCS Piping zt S~ Lucic, t:ni; 2 ChcckcJ'p RcwA!oo No.: 0 Doaia)co< Control 5'n.: Siic=: so.: 6 of 23 Dwo: PEojcoE IO.: C'Wc. f 6 ~ gES9f 1,1356 Material Properties Tnc piping material is SA-353, Class 1, Tge 304 stah!ess steel (-"., 5). Thc mechanical properti s -t room ternperaturc ar (6): S= 30L~i S= 75ksi where S, is the specified minimutt1 yield strength and S is the speci-."ied minimum tensile strength. The Code rninitt1utn properties for the desi'emperature oE 300'F are: S= 22.5 J'si S= 66.0ksi The deQ11ition for tlow stress (o,) assumed in the limitload analysis is to use the average or yield plus ultimate sz natl'.s: G, = (S-: S,)/2 Thetefore, at design temperature: a', = (22.S . 66.0)/2 = ~.~w ksi sL-EH&-sEM5-9 6-lo 2- ~or BE'J. FACE~ OF QAE17 REV 8'96 o ~ ~ I B g ~ ~ ~ Ik ~ I. !3: l;.'!1
QS -6'--S~g ATTACHMENT REV. Calculation No.: AES-C-3566-1 \\
Title:
Evaluation ofCorrosion Dcyadation of24-Inch ECCS Piping at St. Lucic, Unit 2'ade b: Checked by. Revision 5o.: 1 Date Doeutncnt Control No.: I-2 FP&L Project No:. AES 98113566-1 Sheet No.: 7 of23 34 Operating and Accident Stresses The normal operating stresses were conservatively taken as design pressure (P) and dead weight (DW). The maximum stress for accident conditions was taken to include design basis earthquake (DBE) loads P + DW + DBE. Thermal stresses are assumed to be negligible because the system is maintained by FP&Lat ambient conditions. The axial pressure (P) stress by pipe size is computed from: a = p, D./4t with the stress results given as: o. = 60(24)/4(0.25) = 1440 psi The DW, OBE, DBE, and THER "unintensiQed" stresses were supplied by FP&Lfrom design calculations for 24-inch piping (11). The maximum tabulated unintensified stresses are: Code E uation Eq. 8 Eq. 9 Eq. 9 ~Loadin P+ DW P+ DW+ OBE P+ DW+ DBE THER Stress si 1,395 4,099 5,717 6,125 1,580 QAE17 REV 8/96 Received Time Apr. 7, 1:38PM
Calculation No.: AES-C-3566-1
Title:
Evaluation ofCorrosion Degradation of24-Inch ECCS Piping at St. Lucie, Unit 2 Made bv Chcckcd by: Region No.: 1 Date Doctnnent Control No.: Sheet No:. 1-2 8 of23 PSL - E~t ->tWS - lR-ic,2 ATTACHhtiENT REY. FAas 3 srF CUcnt: FPScL Project No.: AES 98113566-1 From this maximum stress case, the membrane (P ), primary bending (P,), and expansion (P,) stresses fornormal and upset (N/U), and emergency and faulted (E/F) conditions are determined. ~Stress si P P, ~N 1,440 4,322 1,580 ~E 1,440 4,730 1,580 3.5 Residual Stresses Local residual stresses at weld areas willbe dominated by the weld residual stress from fabrication. Local weld residual stresses are secondary (displacement controlled) stresses that are self-equilibrating. Therefore, as constraint is relaxed, stresses willtend to attenuate away. Peak stresses at socket welds (fillets) and butt welds typically are yield order in magnitude. Stresses transverse to welds are typically less than longitudinal stresses (7). Transverse stresses are the principal stress ofconcern since they are perpendicular to the circumferential plane containing the cracks. Use of 1/2 yield strength forpeak transverse residual stress has been recommended for fracture analysis ofwelds (7). Since cracks are observed near weldments and not originating withinweld metal, the use of 1/2 yield strength willbe conservative. This peak stress is conservatively assumed to be uniform thxough the thickness. Because the stress willattenuate as through-wall cracks develop and grow in significant length with respect to the pipe circumference, the residual stress is assumed to decay in a linear relationship with crack length and pipe circumference. Therefore, the followingequation is used forweld residual stress: (3-3) whexe, e is the half crack angle. It is, therefore, assumed that when a through-wall crack exists half-way around the pipe, only 50% of the original weld residual stress xexnains due to relaxation. QAE17 REV 8/96 Received Time Apr. V. 1:38PM
@m'acN ENGIIIEERINtrSERVICES IIC ATI'ACHMENT REV. PAGF~O OF~ !"alculntioa No.: AES-C-3566-1 M~by: '"'+ ~/s Qieat: FP&L
Title:
Evaluation ofCorrosion Degradation of24-Inch ECCS Pipirtg at St. Lucio, Unit 2 Checked by: Revision No.: Date: 8 Project No.: AES 9si 13566-1 Document Control No,: Sheet No.: I-2 9 of 23 4.0 4.1 ALLOWABLEFLAWLENGTH Introductioa The allowable Qaw lengths for the ECCS supply piping were established by the limitload analysis for Qawed (Class 1) piping contained in Appendix C ofASME Section XI. The piping material, being austeaitic stainless steel, is highly ductile and net-section plastic behavior willbe expected to be controlling. Further, crackiag is not directly associated with weld metal or is away from the weld zones so that base metal propeities willbe relevant. 4.2 LimitLoad Evaluation Circumferential Flaws The ability of the piping to tolerate. through-wall cracks has been evaluated based oa a net-section plastic collapse. The limitload analysis equations from ASME Section XIforthrou'-wall cracks (a/t = 1) were used, Figure 1 is a schematic illustration of the Qaw model, From ASME Section XI,the crack angle and applied stress level required to cause the remaining pipe cross-section to become fullyplastic is given by: Zcrf P'
(2 siaP sine) 'rt p = [1-(e/n)-{P /err)] (4-1) When(8+ P) 57c, and 2tyf Pb = sing rt p P ~ ITI tyt (4-2) QAE17 REV 8/96 Received Time Apr. V. i:38PM
I ~ ~ I ~ ~ ~ ~ ~ I ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ I ~ ~ I ~ ~ ~ ~ ~ ~ I I ~ I ~ ~ ~ ~ ~ ~ ~ I ~ ~ ' I I I ~ ~ I ~ ~ I I ~ I ~ I ~ ~ ~ ~ ~ ~ ~ ~ ~ I I ~ ~ ~ ~ ~ I ~ I I I ~ I ~ ~ ~ I ~ ~ I ~ I ~ ~ I ~ ~ ~ ~ ~ ~ I I ~ ~ ~ I ~ ~ ~ ~ 'I ~ ~ ~ ~ I ~ ~
Calculation No.: AES-C-3566-1 all'Ln,4n ol 6'1e VALJ' ~ Pgi - EWg gP~g 'l [Oz.~""'TTACHMENT REV. PAGE 1~ OF Qientt FPAL
Title:
Evalvation ofCorrosion Degradation of24-Inch ECCS Piping at St. Lucio, Unit2 Checked by: Revision No.: Date: Docutneat Control Vo.: 1-2 Projea No.: ES 9S113566-1 sbcct No.: ll of 23
- where, o= Pipehoop stress = pD,/2t M,
= [1+ 1.61$ /(4Rt)]'~ ct, = How stress = Total crack length Solving for crack length, the allowable axial crack size is given by: = 3..576(Rt)"' -1 SF' 1/2 (4-5) where the pipe hoop stress, ty, is 2880 psi. The SFs for accepting axial flaws are specified inArticle C-3420 ofAppendix C ofSection XL The Qaw acceptance SFs are: SF = 3.0 SF =15 (normal/upset conditions) (emergency/faulted conditions) 4.4 Results For circumferential flaws, the limitload equations were solved by the iterative process. Equation 4-3 was satisfied for the followingthrough-mall crack lengths: Crack Ange ~em 0.4313 0.5394 Length, ij ~inch 32.18 40.25 Z,4~ 0.03254 0.84222 0.03254 0.67236 ~S si 4322 4730 Received Time Apt. 't, i: 38Phi QAE17 REV S/96
Calcttlatioa No.: AES-C-3566-1 Made b: f'sl -a&t -bcvna -g9 lo~ ATTACHMENT REV. PAGE 13 Client: FPRL
Title:
Evaluation ofCort'oaion Degradation of24-Inch ECCS Piping at St. Lucio, Unit 2'hecked by: M Revision Ão.: Date: Document Control Ko.: I-2 Project No.: AES 98113566-1 Sheet No:. 12 of 23 where ( = 28R (R = mean pipe radius). The smallest computed circumferential flaw length is computed for N/U conditions with I = 32.2 inches. For axial flaws, the allowable flawlength is computed directly from Eq. 4-5. N/U E/F Length, 5 ~inches 13.64 27.69 a~SF a f 5.122 10.243 The smallest computed axial flaw length is computed for N/U conditions with k = 13.6 inches. Received Time Apt'. 7, 1:38PM QAE17 REV 8/96
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N@YMM EttQNEMHQ SHKCES. tNc. Calculation No.: AES-C-3566-1
Title:
Evaluation ofCorrosion Degradation of24-Inch ECCS Piping at St. Lucie, Unit 2 Made y: Chccttcd by: Revision No.: 1 'cc p peal Date Cbcnt: FP&L Froject No.: AES 98113566-1 Document Corttrol No.: Sheet No:, 1-2 16 of 23 VS1-eWC - S~S -3 3 -lo~ ATIACHMENT REV. PAGf 'I + OP~X From this information, a reasonable but conservative bound was established as $, = 0.62 inch based on a 95% probability of occurrence level at 95% coaQdeace (see Appendix A). Likewise, a worst case initialQaw length was determined from the 95%/95% probability of the maximum observed indication lengths from each inspection location. For this case, /j; = 1.18 inches. Therefore, two cases were evaluated, as listed below: Case 1 Case 2 InitialLength, 2a; ~inch 0.62 1.18 Final Length, 2at ~inch 32.2 32.2 5.5 Analysis Results The crack growth analysis was performed in an iterative process followingEq. 5-1. In solving Eq. 5-1, the increments in growth were computed from Eqs. 5-2 and 5-3 for each growth mechanism where aa da = ZN FCG An increment in time of 20 days was assumed, so that N = 2'ycles and t = 480 hours in the summation. For each increment, a new value ofKwas computed from Eqs. 5-4 and 5-5, as the crack length was updated for each increment of growth. The analysis results are summarized. in Appendix B. The results from this analysis are plotted in Figure 3. These results show the change in flaw length as a function ofservice time. By replotting the law growth as a function ofinitiallaw length ($,.), the remaining service time for a given initialthrough-wall length can be determined. This plot is given in Figure 4. QAE17 REV 8/9G Received Time
- API, 7.
1:38PM
ENGINEERNQ SERVICES. HC. Y'hL-Cdte 4BVl5 ATTACMjwaENT RB'. PAGE 18 0 3 Calculation No.: AES-C-3566-1
Title:
Evaluation ofCorrosion Degradation of24-Inch ECCS Piping at St.l.ttcie, Unit 2 Made by: Chcckcd by: Revision Vo.: Detc: Document Control No.: 1-2 Qicat: FPAL Proj ect Yo:. AES 98113566-1 Shcct Yo.: 17 of 23 For an initiallaw length of 0.62 inch (Case 1), the acceptable operational time is about 2,630 days, or 7.2 years. The Case 1'analysis is for a flaw length that represents the 95%/95% bound to the observed surface flawindication lengths and is conservatively assumed to be through-mall. For the worst case law length (Case 2), taken as the 95% bound to the.maximum rejected flaws, where <; = 1.18 inches, the acceptable service time is about 5.4 years. Finally, the longest law that could grow to the allowable size in one operational cycle (1.5 years) was determined. From Figure 4, this flaw length is 6A inches. It is expected that initialflaws lengths willbe detected by evidence of borated water leakage becoming visible. ~ QAE17 REV 8/96 Received Time
- Apr, 7.
1:38PM
mIPVMH ENolHEERM SERVICES, IhC. P51 - EW( -St:yvlS- 'tK-lp2 ATTACHihtiENT REV. PAGE ~~ OF Calculation No.: ABS-C-3566-1 Titie: Evaluation ofCorrosion Deyadation of?A-Inch ECCS Piping at St. Lucie, Unit 2 Made b Chcckcd by: Rmsiott No.: 1 ""'+/ ~v Date: -1 A-em Document Control No.: 1-2 Clicntt FPScL Projcot No.: AES 98113566-1 Shcct No.: 18 of 23 6.0
SUMMARY
OF RESULTS Afiaw evaluation for the ECCS supply piping has been completed foHowing the general methods and acceptance criteria of IWB-3640 and Appendix C ofASME Section XI, Aleak-before-break approach has been used to assess acceptable limits on throu+-wall flaw sizes and acceptable service time for the affected piping. The allowable flaw length for postulated through-wall cracks has been established as 32.2 inches for circumferential flaws and 13.6 inches for axial flaws. These allowable flaw lengths are significantly larger than the observed surface indications. AQaw growth analysis was performed for circumferential fiaws. The circumferential flaw orientation willbe limitingbecause bending and residual stress willbe controlling for SCC at circumferential welds. These stresses are not globally present for axial flaws. For a reasonable but conservative initialflaw length of 0.62 inch, the acceptable service time for the piping is 7,2 years. Ifa worst case Qaw length of 1.18 inches is assumed, the acceptable service time is 5.4 years. The longest through-wall Qaw that could grow to the allowable size in 1.5 years (one operational cycle) is computed to be 6.4 inches. Therefore, the results indicate that adequate safety margins willbe maintained for at least one operational cycle, The structural integrity of the piping is adequate for all design loads per ASME Section XI,provided that leak detection is maintained in the areas affected by external corrosion degradation. QAE17 REV 8/96 Received Time Apt. 7. i:38I'M
Pc l -hH tn - bevtS 1 K-10~ ENGINEEfcHtt SERYlcea. INC. ATlACHhiENT REV. PAGE ZO OF~+ Calculation No.: AES-C-3566-1 Tjtle: Evaluation ofCorrosion Degradation of24-Inch ECCS Piping at St. Lucie, Unit2 lvhd by; Checlccd by; Revision No.: 1 Docutncnt Control No.: 1-2 CUent: FPZcL Project No.t AES 98113566-1 S hect;Vo;t 19 of 23 7.0 1. Inspection Summary Data, Florida Power &Light Company (ECD<). 2. Unit 2 ECCS Inspection Data, Florida Power &Light Company (ECD-5). 3. ASMEBoilerand Pressure Vessel Code, Section XI,Appendix C, "Evaluation of Haws in Austenitic Piping," 1989 Edition. Calculation PSL-2FSM-98-012, Rev. 0, "MinPipe Wall Calculation for 24" CS-2 RWST Suction to CS Pumps Q CS-2-3-SW-1, CS-Z-FW-3, CS-Z-FW-901," Florida Power &Light Company (November 22, 1998) (ECD-2). 5. Calculation PSL-1FSM-98-002, Rev. 0, "MinPipe Wall Calculation for 24" CS-2 and CS-3 in the Outside Pipe Tunnel per CR-98-0047," Florida Power &Light Company (February 9, 1998) (ECD-3). 6. ASMEBoiler and Pressure Vessel Code, Section III,"Appendices," Division 1, 1989 Edition. 7. "Requirements and Guidelines forEvaluating Component Support Materials Under Unresolved Safety Issue A-12,"EPRI NP-3528, Appendix IV,Figure 8-5, Electric Power Research Institute (June 1984). 8. "Evaluation of Flaws in Austenitic Steel Piping," EPRI NP-4690-SR, Special Report, Electric Power Research Institute (July 1986). 9. NUREG-0313, "Technical Report on Material Selection and Processing Guidelines for BWR Coolant Pressure Boundary Piping," Revision 2, US Nuclear Regulatory Commission (June 1986). 10. "Ductile Fracture Handbook," EPRI NP-6301-D, Volume 1, Electric Power Research Institute (June 1989). 11. Revised Stress Results forSI Piping in Pipe Tunnel (A&B Trains), Florida Power &Light Company (April7, 1999) (ECD-10). QAE17 REV 8/96 Received Time
- Apr, V.
l:38PM
~+~ERvm suvcas. Ihc. Calculation iso.: AES-C-3S66-I
Title:
Evaluation of Cortosion Dcyatjation of24-Inch I-:CCS Pipin" at St. Lucie, Unit ". igsdc': Chccccd hy: ~Mc Rcvt:ictt.'vn.: Date (z/i/Pg Doctttttcnt Cootrol.a>0.: I-2 Clicttt: Project Vo.: AES 98 I Ii566-I Shcct iitt.: 20 of 23 r/2 l/// Neutral axis 'Fige e 1 Circumferential Ham ivfodelNet-Section Collapse hfodel. St-CNe. SrM5-9S-[o2- "OF~3 QAEl'7 REV 8!96 'ec. }. 10: l5Plt
~ ~ ~ ~ ~ ~ ~ ~ I ~ ~
rat "~~t -~~ms -1Y-lo~ ATTACHMENT REV. Z3 3 Calculation No.: AES-C-3566-1 Made b: v ~/~v CUcoc; FP&L
Title:
Evaluation ofCorrosion Degradation of24-Inch ECCS Piping at St. Lucio, Unit 2 Checkedby; Rcvisioo No.: Date: project Ão.; AES 98113566-1 Document Control le.: Sheet No.: I-2 22 of 23 FLAW GROWTH EL/ALUATIONRESLILTS ~'50 25 ECCS SUPPLY PIPING t = 0.25" 20 15 10 0 0 500 1000 1500 2000 2500 5000 3500 4000 Service Time, T [daysj Figure 3 Flarv Growth Analysis Results for ECCS Supply Piping. Q~I7 REV 8/96 Received Time Apr. V, 1:38PM
g;tnttaatttttQ 56AcES, at" ATTACHhiENT REV. FAGE + A 0F~~ Calculation No.:
AES-C-3566-1
Title:
Evaluation ofCorrosion Degradation of24-Inch ECCS Piping at St. Lucie, Unit 2 M3dc by. Chcckod by: Revision No.: 1 '"'~ F/ry Date: Docotncnt Control No.: '-2 Giant: PAL Project No,. AES 98113566-1 Sheet No.: 23 of 23 2400 2200 2000 m 1800 l600 il400 E l200 ~ l000 . 800 ~~ 600 400 200 0 FLAW GROWTH EVALUATIONRESULTS ECCS SUPPLY PIPING 0 =24" t = 0.25" 10 15 20 25 30 35 40 Initial Flaw Length, Li (inchesj Figure 4Remaining Service Life Versus InitialCrack Length. QAE11 REv 8/96 Received Time
- AP1, 7,
1:38PbI
~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ e
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V%I V/A OP IICV Jv ~ 'Av > ~~ wvv I v'I vvvy ENCWEBtltIEt SERVICES, NC Calculation No.: AES-C-3566-1
Title:
Evaluation of Corrosion Degradation of ~ ~ ~ ~ 24-Inch ECCS Piping at St. Lucie, Unit2 invade Checked by: Revision No.: 1 Date: Document Control iso,'-2 Chent: FPkL Project ~Vo AZS 98113566-1Q Sheet Vo.: B-1 of B-6 Appendix 3
SUMMARY
OF FLAWGROWTHANALYSISRESULTS Received Time
- Apt,
't. 1:38PbI QAE17 5L 8~(sag 9g ~~par8196 ATTACHMENT REV. PAGE 3~ OF~3
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St. Lucie Unit 2 Docket No. 50-389 L-99-90 Enclosure Attaclunent 2 C. ~30 calendar days D. g Other CONDITION REPORT DUE: Date CR NO. PTNO PSL tK JB Q PAGE 1 OF 0 CO r/I ).. SYSTEM ¹/NAME UNIT 0~ COMPONENT NAME ECC,5 &C77()~ gfyg5 DISCOVERY DATF/TIME C'O CR ORIGINATOR ~ EYENT DATBTIME~I ~ '7 / //IIr/ DEPT/PHONE~~< (L0)- z
- 2. (ATTACHADDmONALPAGES AS NECESSARY)
(A) CONDAIONDESCRIPTION MO~TL('L'7 5p@ ImS Pt= < PDs @(I/Qt ~<( Of / IcLD/etc /Lc. 'Ib rEFs r 5 ~r= mAs ITIVE-mme r= it b.on C5 "g g GCC,5 5L/I-TlC)~ ILI(&i)~K A~M (.5-2. P gC( 4 / I p V C TL 0 ~ 4W )I P P. (B) CAUSEg&QNo~ 4 (C) IMMEDIATEACRONSTAKEN 7 +I~ ~PS C> I5 I + I~ QI) +/rc(Tt/L pLE (D) RECOMMENDEDACTIONSISUGGESTED ASSIGNEE EVE/Ot~~ ~/(' OgI('W/P7'gt-ftC ~OH K0I-z G CC0 (E) ADDITIONALREFERENCES (PWO Number(s). Procedure Number(s). Persorts Co/NecterL etc)
- 3. ORIGINATOR REQUESTS COPY OF CLOSED CONDITION REP RT SUPERVISOR NOTIFICATION:
5'Fry< YES Q N/A 4. OPERABILITY/REPORTABILITYDETERMINATION: A OPERABIUTYASSESSMENT'EQUIRED (3 WORK DAYS) Q B. POTENTIALLYREPORTABLE (ATTACHENS WORKSHEET. IF USED) Q~ NO OPERABIUTYCONCERN/NOT REPORTABLE D. OTHER OUTAGE RELATED7 ~ YES MODE HOLD? Q YES ~NO FOR ENIRYINTOMODE COMMENTS: NPSNPNE PRINT SIGMA E DATEtTIMEf4 7) ~l53
- 5. CONDmON REPORT ASSIGNED TO; COMMENTS:
CI ROOT CAUSE ANALYSIS PGM/ VPNE INVESTIGATE&CORRECT DATE r ~~C,'~ IJT) to:-~~> crDs ro Oo D (9z (L LU LUz8 LU EL LU ODz (0 ILI (L D. LU O) Form sss3 (Dort.stocked) CA'S AAECA AECCAOS V/HENCLOSEO. PLEASE ENSIIAESLL AESPCNSES ANOATTACHMENTSAAE LEQ2LE REV: 422/98
CONDITlON REPORT ¹ PAGE 2 OF 6. NONCONFORMANCE (NCR): El YES FUNCTIONALFAILURE: Q,YES CI NO CI NO BY: PRINT GNATURE 7. INVESllGAlloN:ANALYSIS.CORRECTIVE ACTIONS, GENERIC IMPUCATIONS.DISPOSITiON DETAILS,WORK INSTRUCTIONS (ATTACHAODmloNA. PAGES AS NECESSARY) 5<< <sYrcC r/ /rtp" V opr ogrl,) /rr5rg m pAW Arversa&ru 3 / C ~plg bC. 9I-//8 rrV. I. &S DSc&o* hu A"CHIC.gu pyT "h) 99 FRry~ ~, Ff rg>>,,9(/ yljr ~w, CAUSE CODES: I) 2) 3) 8. DOCUMENTATIONINITIATED: 0 N/A PWO R PCM OTHER EVALUATIONREOUIRED FOR: EO 10CFR50.59 10CFR21 ~ ASME SECTION XI GYES CI NO 0 YES CI NO CI YES 0 NO YES NO
- 9. NCR DISPOSmON:
Q N/A Q REWORK Q REPAIR USE AS.IS ~ OTHER 10. DISFOSmON SIGNATURES: ('/A i!not appEcablo) PREPARER SIGNATURE DEPT PIIONE OTHER DEPT. HEADCONCUR'ATE DATE ANII/SEC XI REVIEWER PNSC/FRG REVIEW? P YES DEPARTMENT HEAD PRINT PRINT PNO SIGNATURE SIGNATURE SIGNATURE DAT DATE 11. OLosEDUT/PRoeLEM sUMMARY: EYENTINmATolL MODE RESTRICTION RELEASED: Q YES Q N/A PRINT SIGNATURE DA Q YES Q No 12. FRG/PNSC REVIEW (ifrequired in Block 10) MTG¹ CHAIRMAN DATE 13. APPROVAL PGMI VPNE / MGR DATE ul cc z to >4 2 Form 8483 (Non-slocket0 CITa ARE OARECORDS WHEN CLOSED. PLEASE ENSURE ALLRESPONSES ANDATTACNMENTSARE LEGI8LE. REV: 4I22S8
CR 99B0445 Attachment 1 Page 1 of 4 INTERIM ENGINEERING DISPOSITION: Back round/Event Descri tion: CR 99-0445 concerns through wall leaks on both Unit 2 Emergency Core Cooling System (ECCS) Trains located within the Refueling Water Storage Tank (RWT) trench as indicated in the attached sketch (Attachment 3). The leak rates are extremely small and not quantifiable; they were discovered by the presence of a small mound of boric acid crystals on the pipe. The unit is currently performing a down power in accordance with TS 3.0.3. ~Di B The subject RWT suction piping provides a flow path from the RWT to the ECCS pumps for use during the Injection Phase following a Design Basis Accident. This function is safety related and is addressed in the plant's FSAR and Technical Specifications. Accordingly, this CR is classified as safety related. As discussed in'Unit 2 FSAR Section 6.3.2.2.4, the RWT is an atmospheric tank containing water borated between 1720 and 2100 ppm. Redundant lines are provided from a single nozzle on the tank to provide suction to the A and B Trains of ECCS Pumps located in the RAB. The suction lines are routed to the RAB in a below grade trench which is open to the atmosphere. Per T.S. 3.5.2, in Modes 1, 2, and 3 (with pressurizer pressure greater than or equal to 1750 psia), two independent ECCS subsystems shall be OPERABLE with independent flow paths capable of taking suction from the RWT. Per T.S. 3.5.3, in Mode 3 (with pressurizer pressure less than 1750 psia) and Mode 4, a minimum of one ECCS subsystem shall be OPERABLE with a flow path to the RWT. Per T.S. 3.1.2.1, in Modes 5 and 6, a minimum of one boron injection flow path shall be OPERABLE which includes a flow path from the RWT via either a charging pump or a HPSI pump, meeting the requirement in T.S. 3.1.2.7b if only the RWT flow path is OPERABLE. The RWT suction lines must be able to pass design flow at a design pressure of 60 psig and a design - temperature of 300'F to the ECCS pumps, have the ability to maintain the pressure boundary and the RAB integrity. Operating pressures are defined by the column of water within the RWT tank and operating temperatures are defined by atmospheric conditions. As detailed within the Total Equipment Database (TEDB) and plant drawings, Lines I-24"-CS-3 (Train A) and I-24"-CS-2 (Train B) are connected to a single nozzle on the RWT and provide suction for the ECCS systems. The piping design pressure is 60 psig at 300'F, with an operating pressure of 30 psig at 120'F. The pipe is 24" schedule 10 (wall thickness of 0.250") in accordance with Ebasco Pipe Code SS-5. Lines I-24"-CS-2 and -3 are designed in accordance with ASME Section III, Class 2 requirements and are constructed of ASTM A-358, Class 1, Type 304 stainless steel material. Unit 2 is currently in the Second Ten Year In-Service Inspection (ISI) Interval. The code of record for Rules for In-Service Inspection in this interval is ASME Section XI 1989.
CR 99-0445 Attachment 1 Page 2 of 4 Evaluation/0 erabilit: CR 99-0445 concerns through wall leaks on Unit 2 Emergency Core CoolingSystem (ECCS) A Train suction line I-24"-CS-2 near a tack weld for the spool nameplate between supports 2412-23 and 2412-20 and on Train B suction line I-24"-CS-3 adjacent to support 2407-17 within the Refueling Water Storage Tank (RWT) Trench. The leak rates are extremely small and not quantifiable; they were discovered by the presence of a small mound of boric acid crystals on the pipe, therefore, operational leakage is not an issue. PSL-ENG-SEMS-98-102 was issued in November 1998 to review the condition of the Unit 2 RWT suction lines. This evaluation developed the system piping design requirements, summarized past identification of indications and examination results, and identified the failure mechanism as chloride induced stress corrosion cracking. The evaluation developed a method for accepting the identified flaws for limited continued operation based on the Acceptance by Evaluation rules of the ASME Section XI Code and demonstrate that the piping is suitable for operation until the Cycle 12 Refueling Outage. APTECH analysis AES-C-3566, Revision 0 was prepared to determine the allowable through wall flaw lengths and expected service life of ECCS supply piping subject to corrosion on the outside surface. The allowable flaw length is based on the acceptance criteria of ASME Section XI, IWB-3640 for all design loading conditions. The evaluation concluded that the allowable flaw length for postulated through wall cracks is 27.8 inches for circumferential flaws and 13.6 inches for axial flaws. As a result, the structural integrity of the piping for all design loads is adequate per ASME Section XI IWC-3122.4 Acceptance by Evaluation criteria provided that flaw lengths are detected prior to their growth to the above size criteria. To provide for the required detection, monthly inspections of the subject piping are conducted to look for through wall leakage. Experience indicates that flaws do not grow to great lengths prior to their propagation through wall. Experience also indicates that through wall flaws result in small, but detectable leaks. Accordingly, the ApTech report requires monthly surveillances of the subject piping to detect through wall leakage. It was under this inspection surveillance that the boric acid crystals were identified on both l-24"-CS-2 and I-24"-CS-3. The leak rates are extremely small and not quantifiable. Since through wall leakage was identified, an operability determination is required. Generic Letter 91-18, "Information to Licensees Regarding NRC Inspection Manual Section on Resolution of Degraded and Nonconforming Conditions," contains guidance for resolution of degraded and nonconforming conditions and Operability determination. Per this Generic Letter, and the NRC Inspection Manual, Part 9900, section 6.15, Operational leakage, leakage through Class 1, 2 or 3 pipe wall is not acceptable for continued operation (except in the case of moderate energy Class 3 piping in accordance with Generic Letter 90-05). Because of this, the Class 2 ECCS suction piping was declared inoperable. As such, the plant declared both trains of the ECCS suction piping OOS. In accordance with TS 3.5.2, the plant has no action statement for the loss of two independent ECCS subsystems. Therefore, the control room entered Applicability specification 3.0.3, a 1 hour LCO to initiate action to place the unit in a MODE in which the specification does not apply by performing a plant shutdown.
CR 99-0445 Attachment 1 Page 3 of 4 A verbal request was made to the NRC regarding application of Generic Letter 91-18 criteria to Class 2 moderate energy systems. This is documented in a phone conversation with the NRC conducted on 4/6/1999. The basis for this request is the design of the ECCS suction piping which is recognized as being similar to low pressure, low energy Class 3 piping. As documented in attachment 2 to this CR the NRC has verbally approved the use of the GL91-18 criteria for Class 3 through wall leaks applicable to the Unit 2 ECCS suction piping Class 2 system. The following is provided which supports Operability of the ECCS suction piping: A review of PSL-ENG-SEMS-98-102 determined that the indications identified above are bounded and within the scope of the evaluation and the Aptech Report. Operational leakage is small and not quantifiable. Meeting TS requirements for RWT inventory assures acceptance of any operational leakage. Consequences of accidental leakage are bounded by the discussion provided in PSL-ENG-SEMS-98-102, Rev. 1. Engineering Evaluation PSL-ENG-SEMS-98-102 provides the current basis for continued operation of St. Lucie Unit 2 ECCS piping based on the determination of the stable through wall flaw length. The analysis recognizes that the calculated stable flaw length is well in excess of any flaw length likely to be observed in the field prior to identification by leakage. The evaluation recognizes that not all axial and circumferential welds within the 1-24"-CS-2 and CS-3 lines have been penetrant inspected. Should flaws be present in these areas, they are and will remain bounded by the evaluation made under Section XI criteria within PSL-ENG-SEMS-98-102. Engineering may recommend additional inspections during the current cycle due to these recent indications. S ecific Corrective Actions: 1. Per NRC phone call, a relief request will be submitted to the NRC per ASME XI 1989 Addition IWA 5250 (3), within 24 hours. Generic Corrective Actions Necessar to Prevent Recurrence: Generic Corrective Actions willbe addressed later.
CR 99-0445 Attachment 1 Page 4 of 4 0 erabilit Statement: The Emergency Core Cooling System is Safety Related as it is required to mitigate the effects of a design basis accident.,The condition, as discussed above, which includes verbal approval by the NRC, allows continued operation. 7'4c Ncc5 5ysce~, ~ c~s;/~~ P ups 4 le <l~l<<
References:
1. St. Lucie 2 FSAR, Amendment 12 2. St. Lucie 2 Technical Specifications, Amendment 98 3. Generic Letter 91-1 8 4. Engineering Evaluation PSL-ENG-SEMS-98-102, Rev1, including Aptech Report. Prep ed eview d: Date /7rrpwi& ~
From: E. J. Weinkam To: File )A PPIac4 ~l 2 cu V~- oVZs l ok 9
Subject:
TELCON Summary Date: Apri16, 1999 Time: 1334 until about 1420 h
Participants:
FPL Stall Kundalkar West Moran Bladow Weinkam NRC/RII Plisco McCree Blake Rudisail Rogers Ross Lanyi Warnick et al. NRC/NRR Berkow Peterson Wichman Gleaves McClellan et al.
Purpose:
FPL called the NRC to discuss the leaks discovered on the Unit 2 ECCS supply lines. Unit 2 entered T/S 3.0.3 for both ECCS trains inoperable at 1100 on 04//06/99. FPL discussed potential relieffrom GL 91-18 (i.e., the requirement to declare the lines inoperable) based on the fact that FPL had a bounding flaw analysis. Summary: The call was made to a bridge line through the NRC's Operations Center. The phone call was recorded. Art Stall summarized the situation ofgrid stability concerns and Turkey Point Unit 4 startup; he also discussed FPL's commitment to fix the flaws in a timely manner. Rusty West summarized plant status; that Unit 2 shutdown had commenced at 1100 and that the unit would be offlineby 1700. Raj Kundalkar summarized the technical issue. Wichman asked service conditions ofpipe; Kundalkar responded and Wichman stated that the piping was, therefore, Class 2 moderate energy. Wichman asked ifwe had done NDE; FPL said no, we would be doing it ASAP.
TELCON Summary - 04/06/99 ~Hrrr4,p p Cg 9Q ~ g4ff/5 P<~ ao)Z. Wichman stated that GL 90-05 and Code Case N513 had been applied in regulatory applications to moderate energy Class 2 piping. 4 Kundalkar stated that we would fixthe leaks ASAP but in no case later than two weeks. Stall stated that we would be replacing the piping at the next outage (April2000). After additional discussion on what was needed, NRR concluded (with the interpretation and NRR position that has been applied in the past) that the GL 91-18 limitation in sections 6.13. and 6.15 that Class 3 flaw evaluations IAWGL 90-05 can be relaxed to apply to OPERABILITYevaluations for moderate energy Class 2 pipes. Wichman stated that FPL would need a reliefrequest to operate for the two-week period with through wall leaks in Class 2 piping. FPL stated that one would be submitted within 24 hours. NRC/NRR (Berkow and Wichman) stated that NRC approval is not required for the 'PERABILITY call. FPL stated that it would characterize the flaws. Wichman said that using GL 91-18, licensees could substitute the words "Class 2" for "Class 3" in piping flaw characterizations conducted IAWGL 90-05. Wichman is expecting a reliefrequest tomorrow (to be sent to Gleaves and Region II). It should address GL 90-05 and Code Case N-513. FPL was requested, based upon a question from McCree, to share with the Senior Resident the number ofprior times that FPL has had to enter the ACTIONStatement to repair through-wall leaks on Unit 2 ECCS suction piping. ECCS Walkdown Details: P8sc4 ~/ S W C~ W7 - d Y~/> P>Pe I of+
- 1. "A"Header Dry white boric acid crystals on the upper right filletweld that attaches the code name plate to the piping spool, approximately i/~" long crack.
Some weepage after plate was removed and area cleaned.
- 2. "B"Header-Dry white boric acid crystals on lower south east lug filletweld adjacent to the pipe clamp for support 2407-17, approximately '/4" in diameter.
No active leakage
- 3. "B"Header Dry white boric acid crystals on upper north west lug for support 2407-17, adjacent to the lug filletweld, less then '/4" in diameter. No active leakage.
Linear indication approximately i/~" long.
- 4. "B"Header Dry white boric acid crystals found on a support member just below support -2407-19. No active leakage.
(No evidence ofleakage or boric acid on the piping could be found). Tho Coste VT-2 Linda ugh VT-2
BII5Lv &~rcAcro Ll/IQuvcw OF ~ic AC/Q l4'loca ok 8<tc 8ctQ
Cg 5/ lr+ qtP c$ cs /p ')( Qr~ (Pt I.i pS C Z-24-CS '2 5 2<OT-180 ~' 'I. / I 5 I I ~ ~ 8"3 r .l ~ 4. o .')" ~ ~ ~ %
CR 99-0445, Page 1 of 4 INTERIM ENGINEERING DISPOSITION: Back round/Event Descri tion: CR 99-0445 concerns through wall leaks on both Unit 2 Emergency Core Cooling System (ECCS) Trains located within the Refueling Water Storage Tank (RWT) trench as indicated in the attached sketch (Attachment 3). The leak rates are extremely small and not quantifiable; they were discoveredby the presence of a small mound of boric acid crystals on the pipe. Attachment 4 to this CR is issued to capture the revision to Aptech Calculation AES-C-3566 and Engineering Evaluations PSL-ENG-SEMS-98-102 identiTied in Attachment 1, state that the operating pressure and temperatures for I-24-CS-2 and I-24-CS-3 are classified as moderate and to address the as found crack length on l-24-CS-3. ~Oi B The subject RWT suction piping provides a flow path from the RWT to the ECCS pumps for use during the Injection Phase following a Design Basis Accident. This function is safety related and is addressed in the plant's FSAR and Technical Specifications. Accordingly, this CR is classified as safety related. As discussed in Unit 2 FSAR Section 6.3.2.2.4, the RWT is an atmospheric tank containing water borated between 1720 and 2100 ppm. Redundant lines are provided from a single nozzle on the tank to provide suction to the A and B Trains of ECCS Pumps located in the RAB. The suction lines are routed to the RAB in a below grade trench which is open to the atmosphere. Per T.S. 3.5.2, in Modes 1, 2, and 3 (with pressurizer pressure greater than or equal to 1750 psia), two independent ECCS subsystems shall be OPERABLE with independent flow paths capable of taking suction from the RWT. Per T.S. 3.5.3, in Mode 3 (with pressurizer pressure less than 1750 psia) and Mode 4, a minimum of one ECCS subsystem shall be OPERABLE with a flow path to the RWT. Per T.S. 3.1.2.1, in Modes 5 and 6, a minimum of one boron injection flow path shall be OPERABLE which includes a flow path from the, RWT via either a charging pump or a HPSI pump, meeting the requirement in T.S. 3.1.2.7b ifonly the RWT flow path is OPERABLE. The RWT suction lines must be able to pass design flow at a design pressure of 60 psig and a design temperature of 300'F to the ECCS pumps, have the ability to maintain the pressure boundary and the RAB integrity. Operating pressures are defined by the column of water within the RWT tank and operating temperatures are defined by atmospheric conditions. As detailed within the Total Equipment Database (TEDB) and plant drawings, Lines I-24"-CS-3 (Train A) and I-24"-CS-2 (Train B) are connected to a single nozzle on the RWT and provide suction for the ECCS systems. The piping design pressure is 60 psig at 300'F, with a maximum normal operating pressure of 30 psig at 120'F which are classified as moderate energy lines (275 psig/200'). The pipe is 24" schedule 10 (wall thickness of 0.250") in accordance with Ebasco Pipe Code SS-5. Lines I-24"-CS-2 and -3 are designed in accordance with ASME Section III, Class 2 requirements and are constructed of ASTM A-358, Class 1, Type 304 stainless steel material. Unit 2 is currently in the Second Ten Year In-Service Inspection (ISI) Interval. The codeof record for Rules for In-Service Inspection in this interval is ASME Section XI 1989.
CR 99-0445, Page 2 of 4 Evaluation/0 erabili CR 99-0445 concerns through wall leaks on Unit 2 Emergency Core Cooling System (ECCS) A Train suction line 1-24"-CS-2 near a tack weld for the spool nameplate between supports 2412-23 and 2412-20 and on Train B suction line I-24"-CS-3 adjacent to support 2407-17 within the Refueling Water Storage Tank (RWT) Trench. The leak rates are extremely small and not quantifiable; they were discovered by the presence of a small mound of boric acid crystals on the pipe, therefore, operational leakage is not an issue. PSL'-ENG-SEMS-98-102 was issued in to review the condition of the Unit 2 RWT suction lines. This evaluation developed the system piping design requirements, summarized past identification of indications and examination
- results, and identified the failure mechanism as chloride induced stress corrosion cracking.
The evaluation developed a method for accepting the identified flaws for limited continued operation based on the Acceptance by Evaluation rules of the ASME Section XI Code and demonstrate that the piping is suitable for operation until the Cycle 12 Refueling Outage. APTECH analysis AES-C-3566, Revision 1 was prepared to determine the allowable through wall flaw lengths and expected service life of ECCS supply piping subject to corrosion on the outside surface. The allowable flaw length is based on the acceptance criteria of ASME Section XI, IWB-3640 for all design loading conditions. The evaluation concluded that the allowable flaw length for postulated through wall cracks is 32.2 inches for circumferential flaws and 13.6 inches for axial flaws. As a result, the structural integrity of the piping for all design loads is adequate per ASME Section XI IWC-3122.4 Acceptance by Evaluation criteria provided that flaw lengths are detected prior to their growth to the above size criteria. To provide for the required detection, monthly inspections of the subject piping are conducted to look for through wall leakage. Experience indicates that flaws do not grow to great lengths prior to their propagation through wall. Experience also indicates that through wall flaws result in small, but detectable leaks. Accordingly, the ApTech report requires monthly surveillances of the subject piping to detect through wall leakage. It was under this inspection surveillance that the boric acid crystals were identified on both I-24"-CS-2 and I-24"-CS-3. The leak rates are extremely small and not quantifiable. Since through wall leakage was identified, an operability determination is required. Generic Letter 91-18, "Information to Licensees Regarding NRC Inspection Manual Section on Resolution of Degraded and Nonconforming Conditions," contains guidance for resolution of degraded and nonconforming conditions and Operability determination. Per this Generic Letter, and the NRC Inspection Manual, Part 9900, section 6.15, Operational leakage, leakage through Class 1, 2 or 3 pipe wall is not acceptable for continued operation (except in the case of moderate energy Class 3 piping in accordance with Generic Letter 90-05). Because of this, the Class 2 ECCS suction piping was declared inoperable. As such, the plant declared both trains of the ECCS suction piping OOS. In accordance with TS 3.5.2, the plant has no action statement for the loss of two independent ECCS subsystems. Therefore, the control room entered Applicability specification 3.0.3, a 1 hour LCO to initiate action to place the unit in a MODE in which the specification does not apply by performing a plant shutdown. The Aptech analysis, AES-C-3566, originally issued in December 1998 identifies that for a worst case flaw of 1.18", for the referenced ECCS piping, the acceptable service life would be 2.7 years. The through wall crack on I-24-CS-3 was identified as a series of cracks with a total length of 1.5" and an assumed length on the ID of the pipe of 2". This exceeds the initial length assumed by Aptech, but based upon the configuration found and the 4 months that have passed since the analysis, this crack is considered bounded by the analysis. Additionally, this crack leaked before further propagation occurred,
CR 99-0445, Page 3 of 4 h as anticipated, and will be removed prior to closure of this CR and within the relief period requested from the NRC. A verbal request was made to the NRC regarding application of Generic Letter 91-18 criteria to Class 2 moderate energy systems.'his is documented in a phone conversation with the NRC conducted on 4/6/1999. The basis for this request is the design of the ECCS suction piping which is recognized as being similar to low pressure, low energy Class 3 piping. As documented in attachment 2 to this CR the NRC has verbally approved the use of the GL91-18 criteria for Class 3 through wall leaks applicable to the Unit 2 ECCS suction piping Class 2 system. The following is provided which supports Operability of the ECCS suction piping: A review of PSL-ENG-SEMS-98-102 determined that the indications identified above are bounded and within the scope of the evaluation and the Aptech Report. Operational leakage is small and not quantifiable. Meeting TS requirements for RWT inventory assures acceptance of any operational leakage. Consequences of accidental leakage are bounded by the discussion provided in PSL-ENG-SEMS-98-102, Rev. 2. Engineering Evaluation PSL-ENG-SEMS-98-102 provides the current basis for continued operation of St. Lucie Unit 2 ECCS piping based on the determination of the stable through wall flaw length. The analysis recognizes that the calculated stable flaw length is well in excess of any flaw length likely to be observed in the field prior to identification by leakage. The evaluation recognizes that not all axial and circumferential welds within the l-24"-CS-2 and CS-3 lines have been penetrant inspected. Should flaws be present in these areas, they are and will remain bounded by the evaluation made under Section XI criteria within PSL-ENG-SEMS-98-102. Engineering may recommend additional inspections during the current cycle due to these recent indications. S ecific Corrective Actions: 1. Per NRC phone call, a relief request will be submitted to the NRC per ASME XI 1989 Addition IWA 5250 (3), within 24 hours. Generic Corrective Actions Necessa to Prevent Recurrence: Generic Corrective Actions will be addressed later.
CR 99-0445, Page 4 of 4 0 erabili Statement: The Emergency Core Cooling System is Safety Related as it is required to mitigate the effects of a design basis accident. The condition, as discussed above, which includes verbal approval by the NRC, allows continued operation. The ECCS system is considered operable.
References:
1. St. Lucie 2 FSAR, Amendment 12 2. St. Lucie 2 Technical Specifications, Amendment 98 3. Generic Letter 91-18 4. Engineering Evaluation PSL-ENG-SEMS-98-102, Rev 2, including Aptech Report. repare: Reviewed Dae
FLORIDA POWER AND LIGHT FACILITYREVIEW GROUP MINUTES APRIL 6, 1999 (Start TIme 1600) FRG 499-053 ST. LUCIE PLANT To: Distribution Chairman: Bob Enfinger Members: Kris Mohindroo Art Singer Wes Bladow Greg Pustover FRG convened on the above date and time with membership as shown. It has been verified a legal quorum exists of the FRG Chairman, or his designated alternate, and four (4) members, including no more th two (2) alternates. Verified by FRG Secreta FRG Secretary: Helga Baranowsky FRG Observers: NRC Inspectors, Ed Weinkam (Licensing), Rick Walker (Training - Protection Services), Rusty West (PGM) The FRG addressed the following items with dispositions as shown:. CR 99-0445 Interim Safety Related Sponsor: Rick Noble Unit 2 A tt 8 ECCS Suction Hdrs During monthly SPG inspection, evidence ol Boric Acid residue was identified on CS-3, 'A'CCS suction header and CS-2CCS suction header. Both ECCS headers dedared OOS at 1190. YES It was determined that an unreviewed safety question as defined by 10 CFR 50.59, did not exist. Also, there were'no 10 CFR 21 concerns unless stated above. Having no further business to conduct, FRG adjourned at 1645. FRG recommends disposition as shown above P approves FRG recommendation 4 FRG Chairm n Date Plant General Manager ate Distribution: R. Acosta, CNRB T. Plunkett, President-Nuclear Division, W. Bladow, QA R. West, Plant General Manager A. Stall, Site Vice President Page 1 of 1 'Walk-in item added to agenda}}