ML14205A228
| ML14205A228 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood  |
| Issue date: | 08/11/2014 |
| From: | Robinson L License Renewal Projects Branch 1 |
| To: | |
| Robinson L, 415-4115 | |
| References | |
| TAC MF1879, TAC MF1880, TAC MF1881, TAC MF1882 | |
| Download: ML14205A228 (7) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 August 11, 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 JULY 21, 2014, BETWEEN THE U.S. NUCLEAR REGULATORY COMMISSION AND EXELON GENERATION COMPANY, LLC CONCERNING DRAFT REQUEST FOR ADDITIONAL INFORMATION, SET 38, 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 July 21, 2014, to discuss and clarify the staffs draft request for additional information (DRAI),
Set 38, 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 7/30/14 8/4/14 8/8/14 8/11/14
SUBJECT:
SUMMARY
OF TELEPHONE CONFERENCE CALL HELD ON JULY 21, 2014, BETWEEN THE U.S. NUCLEAR REGULATORY COMMISSION AND EXELON GENERATION COMPANY, LLC CONCERNING DRAFT REQUEST FOR ADDITIONAL INFORMATION, SET 38, 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
TELEPHONE CONFERENCE CALL BYRON STATION, UNITS 1 AND 2, AND BRAIDWOOD STATION, UNITS 1 AND 2 LICENSE RENEWAL APPLICATION LIST OF PARTICIPANTS July 21, 2014 PARTICIPANTS AFFILIATIONS Lindsay Robinson U.S. Nuclear Regulatory Commission (NRC)
William Holston NRC John Hufnagel Exelon Generating Company, LLC (Exelon)
Don Warfel Exelon Albert Piha Exelon Casey Muggleston Exelon Paul Cervenka Exelon Ralph Wolen Exelon Don Brindle Exelon ENCLOSURE 1
DRAFT REQUEST FOR ADDITIONAL INFORMATION BYRON STATION, UNITS 1 AND 2, AND BRAIDWOOD STATION, UNITS 1 AND 2, LICENSE RENEWAL APPLICATION July 21, 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 July 21, 2014, to discuss and clarify the following draft request for additional information (DRAI),
Set 38, concerning the Byron Station, Units 1 and 2, and the Braidwood Station, Units 1 and 2, license renewal application (LRA).
DRAI 3.0.3-2c Applicability:
Byron Station (Byron) and Braidwood Station (Braidwood), Units 1 and 2
Background:
By letter dated June 30, 2014, the applicant responded to the staffs request for additional information (RAI) 3.0.3-2b Request (2), which revised LRA Sections B.2.1.11, B.2.1.16, and B.2.1.18 to state that:
a) the acceptance criteria for loss of coating integrity will specify that peeling, blistering, and delamination is not acceptable; b) peeling, blistering, or delamination of the coating from the base metal will be entered into the corrective action program; c) if the coating is not repaired or replaced, physical testing will be conducted to ensure that the remaining coating is tightly bonded to the base metal; d) if the coating is not repaired or replaced, the potential for further degradation of the coating will be minimized, (i.e., any loose coating is removed, the edge of the remaining coating is feathered);
e) adhesion testing using American Society for Testing and Materials (ASTM) International standards endorsed in Regulatory Guide (RG) 1.54 will be conducted at a minimum of 3 sample points adjacent to the defective area; f) a certified coatings inspector will assess indications of blisters, cracking, flaking, or rusting and document the condition and acceptance in a post-inspection report; and g) if coatings exhibiting signs of peeling, blistering, or delamination will be returned to service without repair or replacement, the applicant will conduct an evaluation of the potential impact on the system, including degraded performance of downstream components due to flow blockage and loss of material of the coated component.
Issue:
The staff has concluded that immersion coatings that have exhibited delamination or peeling should be repaired or replaced prior to returning the affected component(s) to service unless the degraded coating: (a) has been inspected, tested, evaluated, and partially corrected to minimize the potential for propagation, as described above; and (b) is inspected prior to 2 years from when the degraded condition was detected by the end of the next refueling outage and then again within 2 years by the end of the following refueling outage to ensure that the ENCLOSURE 2
delamination or peeling is not propagating, or the degraded coating is subsequently repaired or replaced.
Request:
Revise LRA Sections B.2.1.11, B.2.1.16, and B.2.1.18 to address corrective actions associated with state that coatings exhibiting peeling or delamination, which will not be repaired or replaced prior to returning the affected component(s) to service., or revise the programs to additionally include a provision to conduct followup visual inspections of the degraded coating by the end of the next refueling outage and then again by the end of the following refueling outage.
Discussion: The applicant requested clarification on the staffs request. The applicant requested the period of time in the Issue be changed to reflect a 2 year vice every outage to allow more flexibility in the management of components taken out of service since some components do not necessarily need to be inspected during outages. The staff agreed to make the change. The applicant also requested that the staff include an option to subsequently repair or replace the degraded coatings in lieu of inspection. As a result, the staff edited the Issue and Request by replacing the reference to outages with a 2 year period and to include an option to repair or replace the degraded coatings in lieu of inspections. Edits to the original DRAI discussed during the teleconference call are noted in italicize for new information and strikethrough for deleted information. This question will be sent as a formal request titled: RAI 3.0.3-2c.
DRAI B.2.1.16-1c Applicability:
Byron and Braidwood
Background:
The detection of aging effects program element of LR-ISG-2012-02 states: [i]nternal visual inspections used to detect loss of material are capable of detecting surface irregularities that could be indicative of wall loss below nominal pipe wall thickness due to corrosion and corrosion product deposition. Where such irregularities are detected, followup volumetric examinations are performed.
The response to RAI B.2.1.16-1b states:
[s]ince the nominal wall thickness is the design wall thickness of new piping, any indications of loss of material, no matter how trivial, would be an indication of wall loss below nominal.
[u]niform corrosion of steel piping in a raw water environment is expected to occur and, as such, the wall thickness of all Fire Protection System piping can be expected to be below the nominal wall thickness.
[i]nternal visual inspections are incapable of providing a quantitative assessment of the amount of wall loss of system components and instead provide only a qualitative assessment of the internal condition of the system.
[a]s such, visual inspection results will be entered into the corrective action program if unexpected levels of degradation are identified. Unexpected levels of degradation include
excessive accumulation of corrosion products and appreciable localized corrosion (e.g., pitting) beyond a normal oxide layer.
Corrective actions may [emphasis added by NRC staff] include follow-up volumetric inspections, if appropriate.
[f]ollow-up volumetric inspections will be performed as determined [emphasis added by NRC staff] by the 10 CFR Part 50 Appendix B corrective action program when visual inspections identify unexpected levels of degradation.
The staff noted that in the previous RAI response dated March 13, 2014, LRA Sections A.2.1.16 and B.2.1.16 were enhanced for Byron only to require a minimum of 30 volumetric examinations during each 3-year interval, as a result of operating experience.
The staff also noted that these sections state that existing volumetric non-destructive examinations will be credited to ensure age-related degradation is identified prior to loss of system intended function.
Issue:
The RAI response outlines the justification for an exception to conducting followup wall thickness measurements when opportunistic internal visual inspections detect loss of material that could be indicative of wall loss below nominal pipe wall thickness. The staff has concluded that the response justifies the basis for why it is impractical to base followup wall thickness measurements on internal qualitative visual inspections.
However, the response does not state what indications of unexpected degradation will result in a followup wall thickness examination.
As an alternative to opportunistic followup wall thickness measurements, the staff recognizes that periodic planned volumetric examinations could be equally effective at detecting loss of material. However, LRA Sections A.2.1.16 and B.2.1.16 do not state a minimum number of volumetric inspections that will be conducted at Braidwood, nor do they state how volumetric inspection locations will be selected at either site. In addition, although the LRA states that the volumetric examinations are being conducted at Byron as a result of operating experience, it is not clear to the staff whether the number of inspections would be reduced based on changes in operating experience.
Request:
Either provide additional details regarding the periodic volumetric examinations to be performed by the Fire Water System program (e.g., number of inspections, provisions for expanding (or reducing) inspections, inspection location selection (methology), or state what indications of unexpected degradation will result in a followup wall thickness examination for opportunistic internal visual inspections.
Discussion: The applicant requested clarification on the staffs request. The applicant noted that a previously submitted RAI response dated March 13, 2014, included an enhancement for Byron, which addressed periodic volumetric examinations. The staff agreed with the approach taken for Byron and made edits to the request to address a similar approach that could be applied to Braidwood. Edits to the original DRAI discussed during the teleconference call are noted in italicize for new information and strikethrough for deleted information. This question will be sent as a formal request titled: RAI B.2.1.16-1c.