ML14245A371
| ML14245A371 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood  |
| Issue date: | 09/16/2014 |
| From: | Robinson L License Renewal Projects Branch 1 |
| To: | Gallagher M Exelon Generation Co |
| Robinson L, 301-415-4115 | |
| References | |
| TAC MF1879, TAC MF1880, TAC MF1881, TAC MF1882 | |
| Download: ML14245A371 (6) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 September 16, 2014 LICENSEE:
Exelon Generation Company, LLC FACILITY:
Byron Station, Units 1 and 2 Braidwood Station, Units 1 and 2
SUBJECT:
SUMMARY
OF TELEPHONE CONFERENCE CALL HELD ON AUGUST 19, 2014, BETWEEN THE U.S. NUCLEAR REGULATORY COMMISSION AND EXELON GENERATION COMPANY, LLC CONCERNING DRAFT REQUEST FOR ADDITIONAL INFORMATION, SET 40, 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 August 19, 2014, to discuss and clarify the staffs draft request for additional information (DRAI),
Set 40, 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
- concurred via email OFFICE LA:DLR PM:RPB1:DLR BC:RPB1:DLR PM:RPB1:DLR NAME
- YEdmonds LRobinson YDiazSanabria LRobinson DATE 9/16/14 9/16/14 9/16/14 9/16/14
SUBJECT:
SUMMARY
OF TELEPHONE CONFERENCE CALL HELD ON AUGUST 19, 2014, BETWEEN THE U.S. NUCLEAR REGULATORY COMMISSION AND EXELON GENERATION COMPANY, LLC CONCERNING DRAFT REQUEST FOR ADDITIONAL INFORMATION, SET 40, PERTAINING TO THE BYRON STATION AND BRAIDWOOD STATION, LICENSE RENEWAL APPLICATION (TAC NOS. MF1879, MF1880, MF1881, MF1882)
DISTRIBUTION EMAIL:
PUBLIC RidsNrrDlr Resource RidsNrrDlrRpb1 Resource RidsNrrDlrRarb Resource RidsNrrDlrRasb 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 August 19, 2014 PARTICIPANTS AFFILIATIONS Lindsay Robinson U.S. Nuclear Regulatory Commission (NRC)
Allen Hiser NRC Jim Medoff NRC John Hufnagel Exelon Generating Company, LLC (Exelon)
Al Fulvio Exelon Tom Quintenz Exelon
ENCLOSURE 2 DRAFT REQUEST FOR ADDITIONAL INFORMATION BYRON STATION, UNITS 1 AND 2, AND BRAIDWOOD STATION, UNITS 1 AND 2, LICENSE RENEWAL APPLICATION August 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 August 19, 2014, to discuss and clarify the following draft request for additional information (DRAI), Set 40, concerning the Byron Station, Units 1 and 2, and the Braidwood Station, Units 1 and 2, license renewal application (LRA).
DRAI 4.7.8-2 Applicable:
Byron Station and Braidwood Station (BBS), all units
Background:
License renewal application (LRA) Section 4.7.8 states that BBS, Units 1 and 2, performed pre-emptive flaw evaluations based on crack growth rate analyses on reactor vessel, pressurizer, primary steam generator sub-components, and primary coolant components. The LRA further states that flaw evaluations, which use fracture toughness as an input, were performed on reactor vessels. The applicant defines these analyses supporting flaw evaluations as plant-specific time limited aging analyses (TLAAs).
Issue:
It is not evident whether these analyses were performed in evaluation of actual flaws detected in Class 1 components at the plant or in evaluation of flaws that were assumed to occur in the components. If these analyses are pre-emptive in evaluation of assumed flaws, the staff seeks further clarification on how the analyses related to meeting all six criteria for defining TLAAs in 10 CFR 54.3(a), especially that for establishing that the analyses are used in a safety-basis decision (safety determination) for the current licensing basis.
Request:
- 1. Clarify whether the analyses discussed and evaluated in LRA Section 4.7.8 were performed on actual flaws that were found at the plant or whether they involve the analyses of assumed flaws in the components.
- 2. If the analyses were performed for any actual flaws, identify the location of the flaw (e.g., the component and the location in the component), the type of flaw, the disposition of the flaw, and whether the flaw currently remains in the component. Also, justify why the flaw should not be identified in the LRA in a manner similar to that for the flaws described in LRA Sections 4.7.4, 4.7.6, and 4.7.7.
- 3. If the analyses are pre-emptive for assumed flaws, then describe how the analyses conform to the six criteria for a TLAA as defined in 10 CFR 54.3.
Discussion: The applicant requested clarification on the staffs request. The staff discussed its concerns regarding whether the flaw analysis was based on actual flaws or assumed flaws.
The applicant explained that actual flaws were used in conjunction with generic flaw evaluation methodology for the flaw analysis. During the discussion, it became apparent that the staffs concern centered around which guidance documents were used to make the flaw analysis determination and which flaw locations, types of flaws, and the systems were involved. As a result of this discussion, the staff generated a revised RAI to encompass the staffs updated concern (see below). The revised RAI below was formally sent to the applicant on August 20, 2014, titled: RAI 4.7.8-2.
RAI 4.7.8-2 Applicable:
Byron Station and Braidwood Station (BBS), all units
Background:
License renewal application (LRA) Section 4.7.8 states that BBS, Units 1 and 2, performed pre-emptive flaw evaluations based on crack growth rate analyses on reactor vessel, pressurizer, primary steam generator sub-components, and primary coolant components.
The LRA further states that flaw evaluations, which use fracture toughness as an input, were performed on reactor vessels. The applicant defines these analyses supporting flaw evaluations as plant-specific TLAAs.
Issue:
The applicants TLAA evaluation basis discussion in the Fatigue Crack Growth Analyses subsection of LRA Section 4.7.8, Analyses Supporting Flaw Evaluations of Primary System Components, does not clearly identify which reactor pressurizer vessel (RPV), steam generator (SG), pressurizer, or reactor coolant pressure boundary (RCPB) piping components had contained flaws and were analyzed in accordance with the generic flaw evaluation methodology in WCAP-11063, "Handbook on Flaw Evaluations For Byron Unit 1 and 2 Steam Generators and Pressurizers" (LRA Reference 4.8.27) and which RPV, SG, pressurizer, or RCPB piping components had contained flaws and were analyzed in accordance with the generic flaw evaluation methodology in WCAP-12046, "Handbook on Flaw Evaluations for the Byron and Braidwood Units 1 and 2 Reactor Vessels" (LRA Reference 4.8.28).
Request:
Describe the RPV, SG, pressurizer, and RCPB flaws that were evaluated in accordance with the flaw evaluation criteria in WCAP-11063 and the RPV, SG, pressurizer, or RCPB flaws that were analyzed in accordance with the generic flaw evaluation methodology in WCAP-12046. Identify the NRC safety evaluation references that were issued in approval of these flaw evaluations.