ML14094A275

Summary of Telephone Conference Call Held on March 19, 2014, Between the U.S. Nuclear Regulatory Commission and Exelon Generation Company, LLC Concerning Draft Request for Additional Information, Set 18, Pertaining to the Byron Station and

ML14094A275
Person / Time
Site:	Byron, Braidwood
Issue date:	05/19/2014
From:	Robinson L License Renewal Projects Branch 1
To:	Gallagher M Exelon Generation Co
Robinson L, 415-4115
References
TAC MF1879, TAC MF1880, TAC MF1881, TAC MF1882
Download: ML14094A275 (7)

Text

May 19, 2014 LICENSEE:

Exelon Generation Company, LLC FACILITY:

Byron Station, Units 1 and 2 Braidwood Station, Units 1 and 2

SUMMARY

OF TELEPHONE CONFERENCE CALL HELD ON MARCH 19, 2014, BETWEEN THE U.S. NUCLEAR REGULATORY COMMISSION AND EXELON GENERATION COMPANY, LLC CONCERNING DRAFT REQUEST FOR ADDITIONAL INFORMATION, SET 18, PERTAINING TO THE BYRON STATION AND BRAIDWOOD STATION, LICENSE RENEWAL APPLICATION (TAC NOS. MF1879, MF1880, MF1881, MF1882)

The U.S. Nuclear Regulatory Commission (NRC or the staff) and representatives of Exelon Generation Company, LLC (Exelon or the applicant), held a telephone conference call on March 19, 2014, to discuss and clarify the staffs draft request for additional information (DRAI),

Set 18, concerning the Byron Station, Units 1 and 2, and the Braidwood Station, Units 1 and 2, license renewal application. The telephone conference call was useful in clarifying the intent of the staffs DRAIs.

provides a listing of the participants, and Enclosure 2 contains a listing of the DRAIs discussed with the applicant, including a brief description on the status of the items.

The applicant had an opportunity to comment on this summary.

/RA/

Lindsay Robinson, Project Manager Projects Branch 1 Division of License Renewal Office of Nuclear Reactor Regulation Docket Nos. 50-454, 50-455, 50-456, and 50-457

Enclosures:

1. List of Participants

2. List of Draft Request for Additional Information cc w/encls: Listserv

ML14094A275

• concurred via email OFFICE LA:DLR*

PM: RPB1:DLR BC:RPB1:DLR PM:RPB1:DLR NAME YEdmonds LRobinson YDiazSanabria LRobinson DATE 5/8/14 5/14/14 5/15/14 5/19/14

SUMMARY

OF TELEPHONE CONFERENCE CALL HELD ON MARCH 19, 2014, BETWEEN THE U.S. NUCLEAR REGULATORY COMMISSION AND EXELON GENERATION COMPANY, LLC CONCERNING DRAFT REQUEST FOR ADDITIONAL INFORMATION, SET 18, PERTAINING TO THE BYRON STATION AND BRAIDWOOD STATION, LICENSE RENEWAL APPLICATION, SET 18 (TAC NOS. MF1879, MF1880, MF1881, MF1882)

DISTRIBUTION EMAIL:

PUBLIC RidsNrrDlr Resource RidsNrrDlrRpb1 Resource RidsNrrDlrRarb Resource RidsOgcMailCenter RidsNrrPMByron Resource RidsNrrPMBraidwood Resource LRobinson DMcIntyre, OPA EDuncan, RIII JBenjamin, RIII AGarmoe, RIII JMcGhee, RIII JRobbins, RIII VMitlyng, RIII PChandrathil, RIII

ENCLOSURE 1 TELEPHONE CONFERENCE CALL BYRON STATION, UNITS 1 AND 2, AND BRAIDWOOD STATION, UNITS 1 AND 2 LICENSE RENEWAL APPLICATION LIST OF PARTICIPANTS March 19, 2014 PARTICIPANTS AFFILIATIONS Lindsay Robinson U.S. Nuclear Regulatory Commission (NRC)

William Holston NRC John Wise NRC Allen Hiser NRC Aloysius Obodoako NRC Ken Karwoski NRC John Hufnagel Exelon Generating Company, LLC (Exelon)

Don Warfel Exelon Al Fulvio Exelon Albert Piha Exelon Gary Becknell Exelon Al Fulvio Exelon Casey Muggleston Exelon Don Brindle Exelon

ENCLOSURE 2 DRAFT REQUEST FOR ADDITIONAL INFORMATION BYRON STATION, UNITS 1 AND 2, AND BRAIDWOOD STATION, UNITS 1 AND 2, LICENSE RENEWAL APPLICATION March 19, 2014 The U.S. Nuclear Regulatory Commission (NRC or the staff) and representatives of Exelon Generation Company, LLC (Exelon or the applicant), held a telephone conference call on March 19, 2014, to discuss and clarify the following draft request for additional information (DRAI), Set 18, concerning the Byron Station, Units 1 and 2, and the Braidwood Station, Units 1 and 2, license renewal application (LRA).

DRAI 3.1.2.3.4-1 Applicability:

Byron and Braidwood, Unit 1

Background:

License renewal application (LRA) Table 3.1.2-4 addresses loss of fracture toughness in steam generator internal structural supports exposed to treated water > 482 ºF at Byron and Braidwood Stations, Unit 1. The LRA states that the steam generator tube support lattice bar is fabricated from SA-240 410S martensitic stainless steel (SS), and the steam generator tube support lattice bar attachment component is fabricated from SA-351 CF3M cast austenitic SS. The LRA Table provides a note H for this component, material, and environment. Note H states that this aging effect (i.e., loss of fracture toughness) is not in NUREG-1801 for the component, material, and environment combination. Visual inspections and eddy current testing were proposed to manage this degradation mechanism.

Issue:

The staff needs additional information concerning the degradation mechanism and the component/environment to ascertain whether the proposed aging management program is adequate.

Request:

Please provide a description briefly discuss the nature of these components (including their function) and the extent to which they are used throughout the steam generator; a sketch/diagram may be useful. Please discuss the susceptibility of these particular components to thermal aging embrittlement (

Reference:

Letter from C.I. Grimes, NRC, to Douglas J.

Walters, Nuclear Energy Institute, License Renewal Issue No. 98-0030, Thermal Aging Embrittlement of Cast Stainless Steel Components, dated May 19, 2000, ML003717179).

Discuss how visual inspections and eddy current testing will be adequate to ensure any loss of fracture toughness that does occur will be limited such that the component will continue to be able to perform its intended safety function during normal operation, transient, and accident conditions. That is, discuss the possibility that the loss of fracture toughness would render the component incapable of performing its function without the component showing any visual evidence of cracking, deformation, or damage.

Discussion: The applicant requested clarification on the staffs request. The applicant requested the staff to identify the applicability of the question and whether there was a need for a sketch or diagram when discussing the steam generator components. The staff agreed to identify the applicability of the question for Byron Unit 1 and Braidwood Unit 1; and after further review, the staff agreed to remove the request for a sketch or diagram. The staff also added eddy currents to the scope of the request as indicated by the underlined portion in the Background and Request sections. All underlined portions indicated additions made to the original DRAI, and the strikethrough indicates a deletion. This question will be sent as a formal RAI titled: RAI 3.1.2.3.4-1.

DRAI 3.0.3-3a Applicability:

Byron and Braidwood

Background:

In a letter dated January 13, 2014, the responses to RAIs 3.0.3-3 and B.2.1.23-1 state that cracking due to stress corrosion cracking is not an aging effect in outdoor air environments for stainless steel and aluminum components that have jacketed insulation.

In regards to potential cracking due to halides in the atmosphere, the responses stated that (a) halide accumulation from the environment is not expected on components that are shielded by jacketed insulation and (b) insulated components located outdoors do not operate at high temperatures where concentration of environmental halides is expected to occur due to evaporation of any present moisture.

The Generic Aging Lessons Learned (GALL) Report aging management program (AMP)

XI.M38, External Surfaces Monitoring of Mechanical Components, recommends visual inspections for leakage to detect cracking on external surfaces that are exposed to an air environment containing halides.

Issue:

The staff recognizes that proper jacketing configuration can be a preventive measure for atmospheric halide intrusion; however, the staff considers a one-time inspection of exposed metal for evidence of cracking as necessary to ensure that the jacketing at Byron and Braidwood is an effective barrier. Also, it is not clear to the staff why the absence of high operating temperatures would prevent moisture from evaporating on an outdoor components surface.

Request:

For insulated stainless steel and aluminum components exposed to outdoor air, provide the technical justification for why exposed metal inspections for cracking are not necessary to confirm the effectiveness of the insulation jacketing in preventing halide intrusion. Alternatively, propose a baseline exposed metal inspection for cracking that may be used to validate the subsequent use of insulation-only inspections and revise the associated AMR items to include cracking as an applicable aging effect.

Discussion: The applicant requested clarification on the staffs request. Minor editorial comments were addressed. In the Background section, the staff decided to specify visual inspections, as indicated by the underlined portion in the last paragraph. It was noted by the applicant that the GALL Report AMP was improperly listed as XI.M38; it will be correctly labeled: XI.M36. The staff decided to include an additional discussion regarding potential leakage of nonwater-filled piping and piping components and agreed to revise the request per the following:

Request:

For insulated stainless steel and aluminum piping and piping components exposed to outdoor air, provide the technical justification for why insulation does not need to be removed to conduct visual inspections to detect cracking in order to confirm the effectiveness of the insulation jacketing in preventing halide intrusion. Alternatively, propose to remove insulation during a baseline inspection for cracking that may be used to validate the subsequent use of insulation-only inspections and revise the associated AMR items to include cracking as an applicable aging effect. For nonwater-filled piping and piping components, state how potential leakage will be identified.

This question will be sent as a formal RAI titled: RAI 3.0.3-3a.