ML15301A252

St. Lucie, Unit 1 - Request for Additional Reply for License Renewal Condensate Storage Tank Cross-Connect Buried Piping Inspection Commitment

ML15301A252
Person / Time
Site:	Saint Lucie
Issue date:	10/06/2015
From:	Katzman E S Florida Power & Light Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
L-2015-258, TAC MF6518
Download: ML15301A252 (4)

Text

0October 6, 2015FPLi L-2015-25810 CFR 50.4U. S. Nuclear Regulatory CommissionAttn: Document Control DeskWashington, DC 20555Re: St. Lucie Unit 1Docket No. 50-335RAI REPLY FOR LICENSE RENEWAL CONDENSATE STORAGE TANKCROSS-CONNECT BURIED PIPING INSPECTION COMMITMENT

References:

1. FPL Letter L-2015-135 dated April 29, 2014, "License Renewal Condensate Storage Tank Cross-Connect Buried Piping Inspection (Unit 1 only) Revised Commitment", ADAMS Accession No.ML15 146A055.2. Request for Additional Information License Renewal Condensate Storage Tank Cross-ConnectBuried Piping Inspection Commitment Florida Power and Light Company St. Lucie Unit No. 1(M1F65 18), ADAMS Accession No. ML1 523 7A4 18.Florida Power & Light (FPL) submitted FPL Letter L-20 15-135 dated May 12, 2015, "License RenewalCondensate Storage Tank Cross-Connect Buried Piping Inspection (Unit 1 only) Revised Commitment"in Reference 1. Reference 2 forwarded a NRC request for additional information (RAI) on the submittal.FPL's response to the RAIs is attached to this correspondence.Please contact Lyle Berry at (772) 467-7680 should you have any questions regarding this submittal.VeryEric S. KatzmnanLicensing ManagerSt. Lucie PlantESK/lrbAttachmentcc: USNRC Regional Administrator, Region IIUSNRC Project Manager, St. Lucie Nuclear PlantUSNIRC Senior Resident Inspector, St. Lucie Nuclear PlantFlorida Power & Light Company6501 S. Ocean Drive, Jensen Beach, FL 34957 L-2015-258AttachmentPage 1 of 3REQUEST FOR ADDITIONAL INFORMATIONLICENSE RENEWAL CONDENSATE STORAGE TANKCROSS-CONNECT BURIED PWPNG INSPECTION COMMITMENTFLORIDA POWER AND LIGHT COMPANYST. LUCIE UNIT NO. 1DOCKET NO. 50-335TAG NO. MF6518By letter dated May 12, 2015 (Agency wide Documents Access and Management System Accession No.ML 15 146A055), Florida Power and Light Company provided information regarding the license renewalcommitment for St. Lucie Plant, Unit No. 1 (St. Lucie) to perform a one-time inspection of theCondensate Storage Tank (CST) cross-connect buried piping, prior to the end of the initial operatinglicense term.The U.S. Nuclear Regulatory Commission (NRC) staff has determined that additional information isrequired to complete its review.RAT 1 For the concrete that encases the CST piping, state the extent (i.e., length and depth) of concretethat was exposed and the condition of the concrete.RAI 2 State the basis for why water intrusion is not expected through the concrete to the surface of thestainless steel CST cross-connect piping, or if the potential for water intrusion exists, why lossof material or cracking of the stainless steel piping is not expected.

L-201 5-25 8AttachmentPage 2 of 3NRC RAI# 1For the concrete that encases the CST piping, state the extent (i.e., length and depth) of concrete that was"_- exposed and the condition of the concrete.FPL Response to RAI # 1On March 29, 2015 excavation activities uncovered a concrete structure at the design location ofthe pipe (8-C-95 Condensate Storage Tank cross-connect). A section of concrete was exposedapproximately 11 feet long. The width was 18 inches and the depth of the concrete was determined to be18 inches by partial (semi-circle) excavation at two locations approximately 6 feet apart on the East side.The West side was not disturbed because design drawings indicated a fire protection pipe was in closeproximity on the West side. The drawings identify the lowest section of the pipe run is at elevation13 feet (the nominal site grade elevation is elevation 18 feet) and this is the approximate location wherethe concrete was exposed.There were no indications of any degradation of the concrete such as cracking, spalling, scaling, pitting,leaching, erosion, settlement, cavitation or abrasion areas, voids, pop outs or exposed reinforcing steel.Debris observed on the concrete duct is from excavated soil and gravel. The concrete duct has roughedges and surface. It can be concluded that this roughness is due to concrete formwork removal during theoriginal construction activities and the condition is in accordance with the original constructionspecification for concrete which states, "for surfaces against which backfill or concrete is to be placed notreatment is required except for repair of defective areas."NRC RAI# 2State the basis for why water intrusion is not expected through the concrete to the surface of the stainlesssteel CST cross-connect piping, or if the potential for water intrusion exists, why loss of material orcracking of the stainless steel piping is not expected.FPL Response to RAI # 2The As-Built isometric drawing for the pipe is dated August 7, 1973. Specific records associated with theconcrete placement for the pipe were not located. Plant operating experience obtained from the buriedpiping program and the observed condition of the concrete which was exposed during the inspection willbe used to support the conclusion that water intrusion does not exist and loss of material or cracking ofthe stainless steel piping is not expected.The excavation site was dry which is consistent with the design. Unit 1 FSAR Figure 3-8.41 "Water Tableat EL + 3 'Loading" and Unit 2 FSAR Section 2.4.13.5 "Design Basis for Subsurface HydrostaticLoading" identify "The water table is at elevation plus 3 feet MVLW [sic] for normal conditions...". Withthe design location being approximately 10 feet above the normal water table, the concrete encased pipeis not likely to be submerged for extended periods of time.Summary_ of Inspection Results from excavation of the pipe / concreteAs stated above, on March 29 2015 excavation activities uncovered a concrete structure at the designlocation of the pipe. This supported the conclusion that the pipe is encased in concrete and not directlyburied.

L-2015-258AttachmentPage 3 of 3No degradation of the concrete such as cracking, spalling, scaling, pitting, leaching, erosion, settlement,cavitation, abrasion, areas, voids, pop outs or exposed reinforcing steel were identified during theinspection. Debris observed on the concrete duct was from excavated soil and gravel. The concrete ducthas rough edges and surface. It can be concluded that this roughness is due to concrete fornwork removalduring the original construction activities.Based on the observed condition of the concrete, water intrusion is not expected through the concrete tothe surface of the stainless steel crosstie piping.Results of the inspection are located in the Corrective Action program under Action Request (AR)02036344.Buried Piping ProgramSt. Lucie has implemented a buried piping inspection program in accordance with NEI 09-14, "Guidelinefor the Management of Underground Piping and Tank Tntegrity"', Rev. 3. Program review determined thatSt. Lucie Unit 2 design documents are very specific and require concrete encasement of buried piping thatis stainless steel or contains licensed material. Since the Unit 1 design documents did not specificallyrequire this encasement, exploratory digs were conducted. In each of the inspections, the piping wasfound to be encased in concrete and the concrete was solid with no delamination. This piping was thenexempt from piping surface inspection as part of the buried piping inspection program, since it wasdetermined to be encased in concrete.In accordance with NEI 09-14 Rev. 3, the St. Lucie buried piping program scope includes safety- related,licensed material, or environmentally hazardous lines. The 8-C-95 line does not fall into this scopingcondition, but was included and credited in the buried piping program due to the St. Lucie one-timelicense renewal conmmitment. St. Lucie's Buried Piping Asset Management Plan is a living document andis periodically updated with inspection results, risk ranking, and future inspection scope.St. Lucie conducted soil sampling as part of the buried piping inspection program. In general, the soil pHwas approximately 9.0, indicating the soil was alkaline. Based on the EPRI presentation, "WhatConstitutes Corrosive Soil", by Doug Munson, dated July 2013, a pH > 8.5 indicates dissolved salts, lowresistivity, and corrosive to cast iron. The CST crosstie piping at St. Lucie is stainless steel and loss ofmaterial or cracking are not expected to occur with the tested soil condition, due to any migration of waterthrough the concrete to the surface of the piping.

References:

1. St. Lucie Action Request Assignment 01681374-06, NEI 09-014 Revision 3, Asset ManagementPlan, St. Lucie Nuclear Station Underground Piping and Tank Integrity Program (UJPTIP),Revision 0.2. St. Lucie Action Request 02036344, License Renewal Inspection of Condensate Cross Tie C 95(a.k.a, 8-C-95).3. St. Lucie Work Order WO 40129353-01, Visual Exam of Buried U1/U2 COND. CROSSTIE8"-C-95.