NOC-AE-12002854, Response to Requests for Additional Information (RAI) B2.1.9-3 (Supplement) for the Renewal Application

Response to Requests for Additional Information (RAI) B2.1.9-3 (Supplement) for the Renewal Application

ML12138A065
Person / Time
Site:	South Texas
Issue date:	05/10/2012
From:	Rencurrel D South Texas
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
G25, NOC-AE-12002854, STI: 33544699, TAC ME4936, TAC ME4937
Download: ML12138A065 (9)

Text

LMmi" Nuclear Operating Company U AEW South Texas ProjectElectric Generatin$Station P.. Box 28,9 Wadsworth. Texas 77483 "/X/V\l May 10, 2012 NOC-AE-12002854 10 CFR 54 STI: 33544699 File: G25 U. S. Nuclear Regulatory Commission Attention: Document Control Desk One White Flint North 11555 Rockville Pike Rockville, MD 20852-2738 South Texas Project 1, Units 1 and 2 Docket Nos. STN 50-498, STN 50-499 Response to Requests for Additional Information (RAI) B2.1.9-3 (Supplement) for the South Texas Proiect License Renewal ADDlication (TAC Nos. ME4936 and ME4937)

References:

1. STPNOC letter dated October 25, 2010, from G. T. Powell to NRC Document Control Desk, "License Renewal Application" (NOC-AE-1 0002607)

(ML103010257)

2. STPNOC letter dated November 21, 2011 from D. W. Rencurrel to NRC Document Control Desk, "Response to Requests for Additional Information for the South Texas Project License Renewal Application (TAC Nos. ME4936 and ME4937)" (NOC-AE-1 1002742) (ML11335A131)

3. STPNOC letter dated March 28, 2012 from D. W. Rencurrel to NRC Document Control Desk, "Response to Requests for Additional Information for the South Texas Project License Renewal Application Aging Management Program, Set 14 (TAC Nos. ME4936 and ME4937)" (NOC-AE-1 2002811) (ML12097A064)

4. Teleconference between STPNOC and the NRC, "Request for Additional Information STP Units 1 and 2 License Renewal Application Aging Management of Internal Coatings of ECW Piping RAI B2.1.9.3B April 24, 2012" (ML12122A002)

By Reference 1, STP Nuclear Operating Company (STPNOC) submitted a License Renewal Application (LRA) for South Texas Project (STP) Units 1 and 2. By References 2 and 3, STPNOC provided responses to Request for Additional Information (RAI) Item B2.1.9-3. By Reference 4, STPNOC agreed to supplement the responses to RAI Item B2.1.9-3. The supplemental response is provided in the Enclosure to this letter.

There are no regulatory commitments in this letter.

L4-7 0Tk

NOC-AE-12002854 Page 2 Should you have any questions regarding this letter, please contact either Arden Aldridge, STP License Renewal Project Lead, at (361) 972-8243 or Ken Taplett, STP License Renewal Project regulatory point-of-contact, at (361) 972-8416.

I declare under penalty of perjury that the foregoing is true and correct.

Executed on W. Rencurrel Chief Nuclear Officer KJT

Enclosure:

STPNOC Supplemental Response to RAI B2.1.9-3

NOC-AE-1 2002854 Page 3 cc:

(paper copy) (electronic copy)

Regional Administrator, Region IV A. H. Gutterman, Esquire U. S. Nuclear Regulatory Commission Kathryn M. Sutton, Esquire 1600 East Lamar Boulevard Morgan, Lewis & Bockius, LLP Arlington, Texas 76011-4511 Balwant K. Singal John Ragan Senior Project Manager Chris O'Hara U.S. Nuclear Regulatory Commission Jim von Suskil One White Flint North (MS 8B1) NRG South Texas LP 11555 Rockville Pike Rockville, MD 20852 Senior Resident Inspector Kevin Polio U. S. Nuclear Regulatory Commission Richard Pena P. 0. Box 289, Mail Code: MN1 16 City Public Service Wadsworth, TX 77483 C. M. Canady Peter Nemeth City of Austin Crain Caton & James, P.C.

Electric Utility Department 721 Barton Springs Road C. Mele Austin, TX 78704 City of Austin John W. Daily Richard A. Ratliff License Renewal Project Manager (Safety) Alice Rogers U.S. Nuclear Regulatory Commission Texas Department of State Health Services One White Flint North (MS 011-Fl)

Washington, DC 20555-0001 Tam Tran Balwant K. Singal License Renewal Project Manager John W. Daily (Environmental) Tam Tran U. S. Nuclear Regulatory Commission U. S. Nuclear Regulatory Commission One White Flint North (MS O11F01)

Washington, DC 20555-0001

Enclosure NOC-AE-1 2002854 Page 1 of 6 STPNOC Supplemental Response to RAI B2.1.9-3 REQUEST FOR ADDITIONAL INFORMATION STP UNITS 1 AND 2 LICENSE RENEWAL APPLICATION AGING MANAGEMENT OF INTERNAL COATINGS OF ECW PIPING RAI B2.1.9-3B APRIL 24, 2012 The U.S. Nuclear Regulatory Commission (NRC or the staff) and representatives of STP Nuclear Operating Company (STPNOC or the applicant) held a telephone conference call on April 24, 2012, to discuss staff concerns related to aging management for internal coatings of essential cooling water piping, in the South Texas Project, Units 1 and 2, license renewal application.(LRA). The telephone conference call was useful in clarifying staff concerns on the issue.

NRC RAI in Reference 4 The discussion centered on the issue of internal (Belzona) coatings in the essential cooling water (ECW) system and whether there was a need to manage the aging effect of fouling of downstream components from pieces that might break off from the internal Belzona coatings in use by the applicant.

The staff expressed its concerns that both industry and plant-specific operating experience have indicated erosions or other instances where the coating has broken off from its installed location and carried downstream where it could potentially clog heat exchangers or otherwise cause fouling of the same. In some recent cases sheet-type failures of the coating have occurred. The staff also stated that contact with industry experts in Belzona indicated that inspection using a "more than visual" approach-such as some sort of physical-mechanical contact-would be necessary to properly inspect an internal Belzona coating. The staffs latest draft RAI, RAI B2.1.9-3b, asks the applicant to state whether there are ECW system locations where intended functions of downstream components could be affected by coating failures. If that is the case, the applicant should revise its LRA to include AMR items in appropriate Table 2s for managing fouling due to coating degradation, and to consider whether its Open Cycle Cooling Water Program should be updated to reflect managing the effect by appropriate types of inspections and inspection frequencies.

The applicant discussed its Belzona operating experience and stated that there have not been coating failures that resulted in any cooling water heat exchanger tube blockage, and there has been no plugging of tubes by Belzona coatings. The applicant also stated that the type of Belzona coating it uses dries to a "phenolic" hardness, and that it does not have the flex or elastic capability to gradually pull away from (or bubble up from) the inner surface to which it had been applied. The applicant also stated that its understanding of the term "fouling" for heat exchangers is included in its aging effect "loss of/reduction of heat transfer" and that examples from its current Table 2s illustrate this. It also stated that the instances of coating

Enclosure NOC-AE-1 2002854 Page 2 of 6 used in the immediate down-stream vicinity of ECW valves are in locations where, if portions broke away, they would be carried out into the ECW cooling pond and would not foul any heat exchangers. Finally, the applicant stated that, in some cases, coatings inside heat exchanger end bells or reversing chambers, or coatings applied to pump discharge volutes are in locations where portions that might break away could potentially impact downstream strainers, heat exchangers or etc.

The applicant agreed that it would take the staffs concerns into account and provide supplemental information intended to address and resolve them, including, as appropriate, examples of AMRs that the applicant believes illustrate that it is managing reduction of heat transfer in at least some cases.

The staff and the applicant agreed that this information would be contained in a supplemental response by the applicant to RAI B2.1.9-3, and that as a result, draft RAI B2.1.9-3b would be dropped. The staff indicated that this would remain an open item in the SER until receipt of information that could resolve the staff concerns.

STPNOC Supplemental Response Summary of STPNOC responses to RAI B2.1.9-3 from References 2 and 3 Certain components in the Essential Cooling Water (ECW) System are coated to protect the underlying metal surfaces from being exposed to the erosive or corrosive effects of the open-cycle cooling water. The three types of coatings are Belzona, Plasticap 400 Epoxy Phenolic, and coal tar epoxy. The essential chiller condenser, standby diesel generator (SDG) lube oil cooler, jacket water cooler, and intercooler water boxes are coated with Belzona 1321 (Belzona 1391 has also been approved for the diesel generator coolers). Interconnecting piping for the intercoolers is lined with Plasticap 400 Epoxy Phenolic. The ECW Intake bay traveling screens are coated with coal tar epoxy. The ECW Pumps are coated with Belzona 1341. Belzona 1341 has also been applied to eroded surfaces of the ECW pump discharge piping 30x24 inch reducer. The piping near the Component Cooling Water (CCW) System heat exchanger ECW return throttle valves is coated with Belzona 2141 and the ECW return throttle valves are coated with Belzona 1341.

The coated ECW pumps are upstream of self-cleaning strainers. The self-cleaning strainers are designed to prevent material larger than 1/16" from entering the component cooling water heat exchangers. The self-cleaning strainer mesh size is smaller than the heat exchanger tubes and serves to protect the heat exchangers from particles greater than 1/16". The coating is inspected during pump disassembly. ECW pump disassembly is scheduled as a refurbishment activity and controlled by the Major Pump and Motor Maintenance Plan. This maintenance plan has a nominal 10 year refurbishment periodicity.

The coated piping near the Component Cooling Water (CCW) System heat exchanger and the coated ECW return throttle valves are downstream of the heat exchangers. Failed Belzona

Enclosure NOC-AE-12002854 Page 3 of 6 coating from these locations does not pass through the CCW System exchangers, but instead flows to piping that returns to the ECW pond. The piping coatings are inspected every five years during planned maintenance PM activities.

The essential chiller condenser, SDG lube oil cooler, SDG jacket water cooler, and SDG intercooler water boxes are inspected every five years.

Interconnecting SDG intercoolers piping is inspected every five years as part of the periodic intercooler inspection.

The ECW intake bay traveling screens upstream of the self-cleaning strainers are inspected during PM activities.

The CCWSystem heat exchangers are periodically performance-tested to verify their heat transfer capabilities. The CCW System heat exchangers are inspected and cleaned on demand based on performance test results. The other safety-related heat exchangers cooled by the ECW System are periodically inspected and cleaned, if required.

Although STP has experienced erosion of coatings in the ECW system, no sheeting-type coating failures have been observed.

General system inspections are performed for macroscopic fouling, biofouling, sediment, corrosion, erosion, pitting, crevice corrosion, and coating failure such as cracks, holes or blister. Various preventive maintenance activities provide for inspection of protective coatings.

The acceptance criteria for coatings are that no erosion, corrosion, blistering, flaking or peeling of the coatings is observed. Coatings not meeting these criteria are considered degraded and a condition report (CR) is initiated to document and resolve the concern.

Continued implementation of the Open-Cycle Cooling Water System program (B2.1.9) and the tracking of plant operating experience provide reasonable assurance that any fouling of in-scope heat exchangers caused by protective coating failures will be adequately managed and will not affect the intended functions of the ECW System heat exchangers.

Supplemental information in response to Reference 4 Heat exchangers exposed to raw water that have a potential of macroscopic fouling due to coating degradation are managed for fouling effects using the following LRA AMR line items.

The aging effect, reduction of heat transfer, is managed using AMP B2.1.9, Open-Cycle Cooling Water System. Applicable LRA tables are provided below:

Enclosure NOC-AE-12002854 Page 4 of 6 Table 3.3.2-4 Auxiliary Systems - Summary of Aging Management Evaluation - Essential Cooling Water and ECW Screen Wash System Component Intended Material Environment Aging Effect. Aging NUREG- Table I Notes Type Function Requiring *Management 1801 Item Management Program. Vol. 2

... _ ...',__ __'Item :__.. ..

Heat HT, PB Copper Raw Water Reduction of heat Open-Cycle VII.C1-6 3.3.1.83 B Exchanger Alloy (Int) transfer Cooling Water (CCW Pump System (B2.1.9)

Room)

Table 3.3.2-6 Auxiliary Systems - Summary of Aging Management Evaluation - Component Cooling Water System Component Intended Material Environment Aging Effect Aging NUREG- Table I Notes Type Function Requiring Management 1801 Item Management Program Vol. 2

• __._"_" '_Item Heat HT, PB Titanium Raw Water Reduction of heat Open-Cycle None None F Exchanger (Int) transfer Cooling Water (CCW Heat System (B2.1.9)

Exchanger)

Table 3.3.2-9 Auxiliary Systems - Summary of Aging Management Evaluation - Chilled Water HVAC System Component Intended Material Environment Aging Effect Aging NUREG- Table I Notes Type Function Requiring Management 1801 Item Management. Program Vol. 2 Item Heat HT, PB Titanium Raw Water Reduction of heat Open-Cycle None None F Exchanger (Int) transfer Cooling Water (AHU System (B2.1.9)

Condenser)

Enclosure NOC-AE-12002854 Page 5 of 6 Table 3.3.2-20 Auxiliary Systems - Summary of Aging Management Evaluation - Standby Diesel Generator and Auxiliaries Component Intended Material Environment Aging Effect Aging NUREG- Table I Notes Type Function Requiring Management 1801 Item Management Program Vol. 2 Item Heat HT, PB Titanium Raw Water Reduction of heat Open Cycle None None F Exchanger (Int) transfer Cooling Water (DG Jacket System (B2.1.9)

Water)

Heat HT, PB Titanium Raw Water Reduction of heat Open-Cycle None None F Exchanger (Int) transfer Cooling Water (DG Lube System (B2.1.9)

Oil)

Heat HT, PB Titanium Raw Water Reduction of heat Open-Cycle None None F Exchanger (Int) transfer Cooling Water (DG Turbo System (B2.1.9)

Air Intercooler)

The use of internal component coatings is controlled by the South Texas Project (STP) design configuration control process and is managed by the preventive maintenance or corrective action programs.

Per the vendor, Belzona 1111 (Super Metal), 1311 ( Ceramic R Metal), 1321 (Ceramic S-Metal),

1341 (Supermetalglide), 1391 (Ceramic HT), and 2141 (ACR-Fluid Elastomer) coatings are not expected to delaminate in large flakes or sheets when applied in accordance with the recommended application instructions. STP installs these coating in accordance with the recommended application instructions and has not experienced any large flaking or sheet failures.

The Belzona application data sheets for the products used do not specify the use of a physical-mechanical contact type of test for cure or adhesion verification. The vendor for Belzona states that testing, such as a pull-off adhesion test, could be used to prove that the coating has not lost any adhesive or cohesive properties. However, this testing results in destruction of the coating.

Aging management program B2.1.9, Open Cycle Cooling Water System, manages the heat exchangers for reduction of heat transfer due to fouling and coatings are visually inspected every five years. Degraded or damaged coatings are documented under the STP corrective action program. Coating repairs are performed using work management control and coating application permit processes.

Plasticap 400 coating is a flexible, thin, baked-on coating. Plasticap 400 Epoxy Phenolic was applied to the internals of the interconnecting piping for the SDG intercoolers by the plant modification process. The evaluation for this modification (Ref: STP Unreviewed Safety Question Evaluation 89-026) concluded that the coating will not separate from the pipe wall in sheets or

Enclosure NOC-AE-12002854 Page 6 of 6 other configurations that could block intercooler tubes after prolonged exposure to ECW System raw water or vibration or earthquake induced pipe deflection. The failure mechanism of this coating application determined after high temperature and pressure testing is blistering. Degraded or damaged coatings are documented under the STP corrective action program and repairs are performed using the work management control and coating application permit processes.

In summary, the permanent coatings applied at STP have not demonstrated any operating experience where the coating has broken off from its installed location and fouled downstream heat exchangers in a manner that adversely affected their intended function. When properly applied, Belzona coatings are not expected to delaminate in large flakes or sheets between inspection intervals. The Open Cycle Cooling Water System program (B2.1.20) in addition to performance testing, requires periodic inspection and cleaning of ECW heat exchangers, and periodic inspection of internals where coatings are applied. Operating history demonstrates that the effects of aging are being managed adequately by the Open Cycle Cooling Water System,.

program (B2.1.20) to maintain the intended functions of the ECW system through the period of extended operation.