ML23096A007

NRR E-mail Capture - Final Request for Additional Information - Callaway Plant, Unit 1 - License Amendment Request to Revise TS 5.5.16 for Permanent Extension of Integrated Leak Rate Testing - EPID L-2022-LLA-0165

ML23096A007
Person / Time
Site:	Callaway
Issue date:	04/05/2023
From:	Mahesh Chawla NRC/NRR/DORL/LPL4
To:	Elwood T Ameren Missouri
References
L-2022-LLA-0165
Download: ML23096A007 (10)

Text

From: Mahesh Chawla Sent: Wednesday, April 5, 2023 6:28 PM To: Elwood, Thomas B Cc: Jennifer Dixon-Herrity; Ian Tseng; Ata Istar; David Nold; Brian Wittick; Brian Lee; Gurjendra Bedi; Stewart Bailey; Jerry Dozier; Reinaldo Rodriguez; Ahsan Sallman; Diana Woodyatt; Clinton Ashley; Vic Cusumano; Antonios Zoulis

Subject:

Final Request for Additional Information - Callaway Plant, Unit 1 - License Amendment Request to revise TS 5.5.16 for Permanent Extension of Integrated Leak Rate Testing - EPID L-2022-LLA-0165 Attachments: Callaway TS 5.5.16 LAR - Final RAI_040523.docx

Dear Mr. Elwood,

By letter dated November 3, 2022 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML22307A310), Ameren Missouri (Union Electric Company, the licensee) submitted a license amendment request (LAR) for Callaway Plant, Unit 1. The proposed LAR would revise the Technical Specifications (TS) 5.5.16, Containment Leakage Rate Testing Program, to allow for the permanent extension of the Type A Integrated Leak Rate Testing (ILRT) and Type C Leak Rate Testing frequencies based on the guidance in NEI 94-01, Industry Guideline for Implementing Performance-Based Option of 10 CFR 50, Appendix J, (Rev. 3-A).

Specifically, the proposed change will revise Callaway Plant's TS 5.5.16 by replacing the references to Regulatory Guide 1.163, "Performance-Based Containment Leak-Test Program,"

with a reference to NEI 94-01, Revision 3-A, dated July, 2012, and the limitations and conditions specified in NEI 94-01, Revision 2-A, dated October 2008, as the documents used to implement the performance-based containment leakage testing program in accordance with Option B of 10 CFR 50, Appendix J, "Primary Reactor Containment Leakage Testing for Water-Cooled Power Reactors."

Request for Additional Information After reviewing the Licensees request, the U.S. Nuclear Regulatory Commission (NRC) staff determined that additional information was required to complete its review. The draft RAI request was sent to you on 3/29/23 asking you to set up a clarification call with the NRC staff. In an email on 4/4/23, you informed us that there was no need for a clarification call. You also requested 60 days to provide your response to the final RAIs on the docket. Therefore, please provide your response to the subject RAIs on the docket prior to 06/05/23. Thanks Sincerely,

Mahesh Chawla, Project Manager Plant Licensing Branch IV Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission ph: 301-415-8371 Docket No. 50-483 OFFICE DORL/LPL4/PM DORL/LPL4/BC JDixon-NAME MChawla Herrity DATE 4/5/23 4/5/23

Hearing Identifier: NRR_DRMA Email Number: 2031 Mail Envelope Properties (SA1PR09MB84150CD98DAA5A756D7398B9F1909)

Subject:

Final Request for Additional Information - Callaway Plant, Unit 1 - License Amendment Request to revise TS 5.5.16 for Permanent Extension of Integrated Leak Rate Testing -

EPID L-2022-LLA-0165 Sent Date: 4/5/2023 6:27:38 PM Received Date: 4/5/2023 6:27:39 PM From: Mahesh Chawla Created By: Mahesh.Chawla@nrc.gov Recipients:

"Jennifer Dixon-Herrity" <Jennifer.Dixon-Herrity@nrc.gov>

Tracking Status: None "Ian Tseng" <Ian.Tseng@nrc.gov>

Tracking Status: None "Ata Istar" <Ata.Istar@nrc.gov>

Tracking Status: None "David Nold" <David.Nold@nrc.gov>

Tracking Status: None "Brian Wittick" <Brian.Wittick@nrc.gov>

Tracking Status: None "Brian Lee" <Brian.Lee@nrc.gov>

Tracking Status: None "Gurjendra Bedi" <Gurjendra.Bedi@nrc.gov>

Tracking Status: None "Stewart Bailey" <Stewart.Bailey@nrc.gov>

Tracking Status: None "Jerry Dozier" <Jerry.Dozier@nrc.gov>

Tracking Status: None "Reinaldo Rodriguez" <Reinaldo.Rodriguez@nrc.gov>

Tracking Status: None "Ahsan Sallman" <Ahsan.Sallman@nrc.gov>

Tracking Status: None "Diana Woodyatt" <Diana.Woodyatt@nrc.gov>

Tracking Status: None "Clinton Ashley" <Clinton.Ashley@nrc.gov>

Tracking Status: None "Vic Cusumano" <Victor.Cusumano@nrc.gov>

Tracking Status: None "Antonios Zoulis" <Antonios.Zoulis@nrc.gov>

Tracking Status: None "Elwood, Thomas B" <TElwood@ameren.com>

Tracking Status: None Post Office: SA1PR09MB8415.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 2154 4/5/2023 6:27:39 PM Callaway TS 5.5.16 LAR - Final RAI_040523.docx 35228

Options Priority: Normal Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:

REQUEST FOR ADDITIONAL INFORMATION LICENSE AMENDMENT REQUEST TO PERMANENT EXTENSION OF TYPE A AND TYPE C LEAK RATE TEST FREQUENCIES CALLAWAY UNIT 1 DOCKET NO. 50-483

Background

By letter dated November 3, 2022 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML22307A310), Ameren Missouri (Union Electric Company, the licensee) submitted a license amendment request (LAR) for Callaway Plant, Unit 1. The proposed LAR would revise the Technical Specifications (TS) 5.5.16, Containment Leakage Rate Testing Program, to allow for the permanent extension of the Type A Integrated Leak Rate Testing (ILRT) and Type C Leak Rate Testing frequencies based on the guidance in NEI 94-01, Industry Guideline for Implementing Performance-Based Option of 10 CFR 50, Appendix J, (Revision 3-A).

Specifically, the proposed change will revise Callaway Plant's TS 5.5.16 by replacing the references to Regulatory Guide 1.163, "Performance-Based Containment Leak-Test Program,"

with a reference to NEI 94-01, Revision 3-A, dated July, 2012, and the limitations and conditions specified in NEI 94-01, Revision 2-A, dated October 2008, as the documents used to implement the performance-based containment leakage testing program in accordance with Option B of 10 CFR 50, Appendix J, "Primary Reactor Containment Leakage Testing for Water-Cooled Power Reactors."

Request for Additional Information (RAI)

After reviewing the Licensees request, the U.S. Nuclear Regulatory Commission (NRC) staff has determined additional information is required to complete its review. The requests are described below.

SCPB RAIs:

Regulatory Basis 10 CFR 50.54(o) requires primary reactor containments for water-cooled power reactors to be subject to the requirements of Appendix J to 10 CFR 50. Appendix J specifies containment leakage testing requirements, including the types required to ensure the leak-tight integrity of the primary reactor containment and systems and components which penetrate the containment. In addition, Appendix J discusses leakage rate acceptance criteria, test methodology, frequency of testing and reporting requirements for each type of test. The testing requirements in Appendix J ensure that: (a) leakage through containments or systems and components penetrating containments does not exceed allowable leakage rates specified in the TSs, and (b) integrity of the containment structure is maintained during the service life of the Page 1 of 6

containment.Section V.B.3 of 10 CFR 50, Appendix J, Option B, requires the licensee to develop a performance-based leakage-testing program using the RG or other implementation document and referencing it in the plant TS. Option B specifies performance-based requirements and criteria for preoperational and subsequent leakage rate testing. These requirements are met by:

1. Type A tests to measure the containment system overall integrated leakage rate,

2. Type B pneumatic tests to detect and measure local leakage rates across pressure retaining leakage-limiting boundaries such as penetrations, and

3. Type C pneumatic tests to measure containment isolation valve leakage rates.

RAI-SCPB-01:

On May 28, 1996, the NRC approved Amendment No. 111 to the facility operating license for Callaway, which allowed the implementation of Option B to 10 CFR Part 50, Appendix J. This allowed for the implementation of a performance-based option for determining the test frequency for containment leakage rate testing in accordance with RG 1.163 and American National Standards Institute/American Nuclear Society ANSI/ANS 56.8-1994, American National Standard for Containment System Leakage Testing Requirements.

LAR Section 3.5.6, Type B and Type C Local Leak Rate Testing Program Implementation Review states that Of 65 Type B penetrations, 7% [percent] of the Type B penetrations are on extended intervals. The staff reviewed FSAR Section 6.2.6.2 Containment Penetration Leakage Rate Tests (Type B Tests), which infers that all but 9 of the 65 Type B leakage rate tests are associated with electrical penetrations.

The licensee is requested to provide clarification as to why such a small percentage (i.e., 7 percent) of the Type B penetrations are on extended local leak rate test (LLRT) frequencies.

Specifically, the licensee is requested to confirm that the low percentage is not an indication of poor performance.

RAI-SCPB-2 The staff reviewed LAR Table 3.5.6-1, Callaway Types B and C LLRT Combined As-Left Trend Summary, and identified that it does not include results for the "as-found" minimum pathway leakage rates for the subject refueling outages nor results for the percentage of 0.6La (percent/24 hours).

The staff notes that the "as-found" minimum pathway leakage rates from the current refueling outage [i.e., when combined with as left maximum pathway leakage rates from the previous two or three refueling outages corrected for understatement where appropriate] are the true measure of the effectiveness of the Licensees Type B and Type C penetration maintenance program.

For the subject refueling outages, the staff requests that the licensee provide the summation results for the "as-found" minimum pathway leakage rates. These results should be conveyed in standard cubic centimeters per minute (sccm). In addition, staff requests these results also be conveyed as a percentage of 0.6La, which is the maximum allowable leakage rate at design Page 2 of 6

pressure for all Type B and Type C penetrations tested. More precisely, the combined leakage rate for "as-found" minimum pathway leakage rates from the current refueling outage [i.e., when combined with as left maximum pathway leakage rates from the previous two or three refueling outages corrected for understatement where appropriate] of all Type B and Type C tested penetrations must be less than or equal to 0.6 La.

This additional information is needed to support a staff conclusion that the Callaway plant has demonstrated a history of adequate Appendix J Type B and Type C component maintenance.

RAI-SCPB-3 LAR Section 3.6.7, Local Leak Rate Testing Program Effectiveness, Example #3 details a long-lived and still to be resolved problem with Essential Service Water primary containment penetrations 28, 29, 71 and 73.

The staff reviewed Table 3.5.6-1, Callaway Types B and C LLRT Combined As-Left Trend Summary, and found that the problem existed during refueling outage RF20 of 2014. During the subsequent RF21 of 2016, the As-Left MXPLR was dramatically reduced for reasons not sufficiently explained in the LAR from 170,116.74 sccm to 53,139.63 sccm.

LAR Section 3.6.6, Containment Isolation System (SM) Exceeded the Maintenance Rule (MR)

Performance Criteria - RF20 (2014), concludes:

All of these performance requirements are currently satisfied with one exception: the Containment Leakage for Type B and C tests shall be less than or equal to 0.4 La which equates to 168,018.4 SCCM.

Discussion or Explanation of Event as contained in Example #3 of LAR Section 3.6.7, indicates that as early as 2013 (RF19) there have been LLRT testing issues associated with these four penetrations. This same Discussion also reads in part:

The issue with EFV0343, 344, 345 and 346 started in RF17[sic 2010]. During RF17, it was identified that the valve seats in these valves were so worn that isolation was not occurring to support an LLRT of the valves in penetrations 28, 29, 71, and 73.

This Discussion concluded with the paragraph:

After RF20, HI [sic Health Issue] 2014019 was written to attain replacement valves. This combined with the Appendix J program being MR (a)(1) produced the necessary priority to attain replacement valves. Currently, BOM 403172 is in process to obtain vendor quotes to attain replacement valves. The work of replacement is floating between RF22 [sic 2017] and RF23 [sic 2019].

LAR Section 3.6.7 concluded that:

Table 3.5.6-1, Callaway Types B and C LLRT Combined As-Left Trend Summary, shows the effectiveness of the corrective actions taken to address LLRT Program Effectiveness.

For the Type C testing associated with penetrations 28, 29, 71, and 73, the staff notes that the conclusion for Section 3.6.7 is not supported by the corrective actions dating back to 2010. The Page 3 of 6

licensee is requested to provide additional information to adequately support the conclusion of Section 3.6.7 for these penetrations.

ESEB RAIs RAI-ESEB-1

Background:

In Section 3.6, Operating experience (OE), of the LAR, the site specific and industry events were evaluated for impacts on the Callaway containment that included Regulatory Issue Summary (RIS) 2016-07:

Containment Shell or Liner Moisture Barrier Inspection, in Subsection 3.6.5 of the application. The licensee states in Subsection 3.6.5: Callaway does not have a moisture barrier seal that adjoins the concrete floor to the liner plate. Rather, a one-foot-thick fill slab is installed over the liner plate at both the 2000' elevation floor of containment and the 1970' elevation floor of the incore tunnel area in containment. The fill slab is installed directly over the horizontal liner plate on the floor, and directly against the vertical liner plate on the wall.

In Table 3.5.2-1, Subsection IWE Summary Table, of the LAR, the licensee identifies Item Number E1.30, Moisture Barrier, referring to Note 6, under Relief Request of Reference Number, which states The Callaway containment design does not include wetted surfaces of submerged areas or moisture barrier. In Table 3.5.2.-4, Containment Inspection Relief Request, of the LAR, the licensee states, No IWE Relief Requests have been submitted at this time.

As described in RIS 2016-07, the NRC staff identified several instances in which containment shell or liner moisture barrier materials were not properly inspected in accordance with American Society of Mechanical Engineers (ASME) Code Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, Subsection IWE, Table IWE-2500-1, Examination Category E-A, Containment Surfaces, Item E1.30. Note 4, where Figure IWE-2500-1, Examination Area for Moisture Barriers, shows examinations areas of typical moisture barrier.

Regulatory Basis:

10 CFR 50.55a, Codes and standards, paragraph (g), Inservice inspection requirements, require, in part, that licensees implement an inservice inspection program for metal containments and metallic liners of concrete containments. The program shall be in accordance with the latest edition and addenda of Subsection IWE of Section XI of the ASME Code that has been incorporated by reference in 10 CFR 50.55a(b) 12 months before the start of the 120-month inspection interval and is subject to the applicable conditions in 10 CFR 50.55a(b)(2)(ix).

10 CFR 50.55a, Codes and standards, paragraph (b)(2)(ix)(K), Metal Containment Examinations, requires, in part, states A general visual examination of containment leak chase Page 4 of 6

channel moisture barriers must be performed once each interval, in accordance with the completion percentages in Table IWE 2411-1 of the 2017 Edition.

Section XI of ASME Code, Item E1.11, in Table IWE-2500-1 (E-A), Examination Category E-A, Containment Surfaces, requires general visual examination of 100 percent of accessible surface areas during each inspection period, while Item E1.30 in the same table requires general visual examination of 100 percent of accessible moisture barriers during each inspection period. Note 4 (Note 3 in editions before 2013) for Item E1.30 under the Parts Examined column states, Examination shall include moisture barrier materials intended to prevent intrusion of moisture against inaccessible areas of the pressure retaining metal containment shell or liner at concrete-to-metal interfaces and at metal-to-metal interfaces which are not seal-welded. Containment moisture barrier materials include caulking, flashing, and other sealants used for this application.

Issue:

Regarding the interface between the installed concrete fill slab and the vertical liner plate on the containment wall, it is not clear how moisture intrusion into inaccessible areas of the pressure retaining containment liner under the slab will be prevented without some type of moisture barrier material.

Request:

Describe the interface design at the installed concrete fill slab directly against the vertical liner plate on the containment wall and describe any features that prevent intrusion of moisture into inaccessible areas of the pressure retaining metal containment liner under the slab.

RAI-ESEB-2

Background:

In Subsection 3.1.2, Post-Tensioning System, the licensee states: The tendon duct provides an enclosed space surrounding each tendon. After stressing, a petroleum-based corrosion inhibitor is pumped into the duct. However, the licensee did not provide any discussion of what acceptance criteria is being used for the petroleum-based corrosion inhibitor in the ducts, which is an integral part of the containment tendon system. The licensee also describes acceptance criteria sporadically for Types A, B, and C tests, IWE, IWL tendon tensioning test, liner coating, throughout the LAR and did not refer to and/or provide the Callaway procedures outlining the actual inspection procedures and, specifically, the examination acceptance criteria.

Regulatory Basis:

10 CFR 50, Appendix J Primary Reactor Containment Leakage Testing for Water-Cooled Power Reactors Background, provides the test requirements and acceptance criteria for preoperational and periodic leakage rate testing of the reactor containment and of systems and components which penetrate the containment.

Page 5 of 6

10 CFR 50.55a and 10 CFR 50, Appendix A, General Design Criteria for Nuclear Power Plants, General Design Criteria (GDC) 1, as they relate to concrete containment being designed, fabricated, erected, tested, and inspected to quality standards commensurate with the importance of the safety function to be performed.

10 CFR 50, Appendix A, GDC 16, as it relates to the capability of the concrete containment to act as a leak-tight membrane to prevent the uncontrolled release of radioactive effluents to the environment.

ASME Section III, Subsection IWL, Sub-article IWL-2525, Examination of Corrosion Protection Medium and Free Water, specifies the acceptance limits of a grease sample removed, analysis, removal/replacement from the required tendons, and acceptance limits (Table IWL-2525-1).

Issue:

The licensee did not clearly define and describe the inspection procedures and examination acceptance criteria for Types A, B and C tests, the IWE and IWL examinations, the containment liner coating, and the petroleum-based corrosion inhibitor.

Request:

Provide on the portal or clearly describe the Callaway inspection procedures and the examination acceptance criteria for Types A, B, and C tests, the IWE and IWL examinations, the containment liner coating, and the petroleum-based corrosion inhibitor.

Page 6 of 6