ML14133A701
| ML14133A701 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood  |
| Issue date: | 05/21/2014 |
| From: | Robinson L Division of License Renewal |
| To: | Gallagher M Exelon Generation Co |
| References | |
| TAC MF1879, TAC MF1881, TAC MF1882, TAC MF1980 | |
| Download: ML14133A701 (6) | |
Text
May 21, 2014 Mr. Michael P. Gallagher Vice President, License Renewal Projects Exelon Generation Company, LLC 200 Exelon Way Kennett Square, PA 19348
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION FOR THE REVIEW OF THE BYRON STATION, UNITS 1 AND 2, AND BRAIDWOOD STATION, UNITS 1 AND 2, LICENSE RENEWAL APPLICATION, SET 26 (TAC NOS. MF1879, MF1880, MF1881, AND MF1882)
Dear Mr. Gallagher:
By letter dated May 29, 2013, Exelon Generation Company, LLC, submitted an application pursuant to Title 10 of the Code of Federal Regulations Part 54, to renew the operating licenses NPF-37, NPF-66, NPF-72, and NPF-77 for Byron Station, Units 1 and 2, and Braidwood Station, Units 1 and 2, respectively, for review by the U.S. Nuclear Regulatory Commission (NRC or the staff). The staff is reviewing the information contained in the license renewal application and has identified, in the enclosure, areas where additional information is needed to complete the review.
These requests for additional information were discussed with John Hufnagel, and a mutually agreeable date for the response is within 30 days from the date of this letter. If you have any questions, please contact me at 301-415-4115 or by e-mail at Lindsay.Robinson@nrc.gov.
Sincerely,
/RA/
Lindsay R. 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
Enclosure:
Request for Additional Information cc w/encl: Listserv
ML14133A701 *concurred via email OFFICE LA:DLR* PM: RPB1:DLR BC:RPB1:DLR PM:RPB1:DLR NAME IKing LRobinson YDiazSanabria LRobinson (JDaily for)
DATE 5/14/14 5/19/14 5/21/14 5/21/14
Letter to M.P. Gallagher from Lindsay R. Robinson dated May 21, 2014
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION FOR THE REVIEW OF THE BYRON STATION, UNITS 1 AND 2, AND BRAIDWOOD STATION, UNITS 1 AND 2, LICENSE RENEWAL APPLICATION, SET 26 (TAC NOS. MF1879, MF1880, MF1881, AND MF1882)
DISTRIBUTION:
EMAIL:
PUBLIC RidsNrrDlr Resource RidsNrrDlrRpb1 Resource RidsNrrDlrRarb Resource RidsNrrDlrRasb Resource RidsOgcMailCenter RidsNrrPMByron Resource RidsNrrPMBraidwood Resource
LRobinson DMcIntyre, OPA JMcGhee, RIII EDuncan, RIII JBenjamin, RIII AGarmoe, RIII JRobbins, RIII VMitlyng, RIII PChandrathil, RIII
BYRON STATION, UNITS 1 AND 2 AND BRAIDWOOD STATION, UNITS 1 AND 2 LICENSE RENEWAL APPLICATION REQUEST FOR ADDITIONAL INFORMATION, SET 26 (TAC NOS. MF1879, MF1880, MF1881, AND MF1882)
RAI 4.7.4-1a Applicability:
Byron Station (Byron) and Braidwood Station (Braidwood), Units 1 and 2
Background:
By letter dated March 28, 2014, the applicant responded to request for additional information (RAI) 4.7.4-1 which addresses the applicants fracture mechanics analysis for the flaws detected in the tube side inlet and outlet nozzles of residual heat removal (RHR) heat exchangers. As part of the response, the applicant provided information regarding when it performed the most recent volumetric examinations on each nozzle of the Byron and Braidwood RHR heat exchangers. The applicant also indicated that the most recent volumetric examinations for the RHR heat exchanger nozzles were those performed in 1994 on Braidwood, Unit 2, RHR heat exchanger nozzles.
During its review of the applicants response and related information, the staff noted NRC letter dated February 29, 1996 (ADAMS Accession No. 9603060023), which encloses the staffs safety evaluation regarding the Byron and Braidwood request for relief (Nos. NR-18 and NR-23) from the volumetric examinations of the RHR heat exchanger nozzles for the first 10-year inservice inspection interval. This safety evaluation discusses the previous inspection requirements which are specified in the staffs safety evaluation, dated February 3, 1995 (ADAMS Accession No. 9502130021), regarding the flaws detected in these nozzles and the applicants fracture mechanics analysis for the flaws subject to the evaluation of American Society of Mechanical Engineers (ASME)Section XI, IWB-3600.
The February 29, 1996, safety evaluation further states that instead of the previous requirements specified in the February 3, 1995, safety evaluation, the licensee is required to perform ultrasonic testing (UT) examinations on a sample of RHR nozzle-to-vessel welds (one nozzle per unit) during the next inspection interval (i.e., the second interval) to provide additional assurance that these flaws have not grown and that no new service induced indication has developed.
In its review of the applicants RAI response, the staff also noted that the applicants letter dated July 25, 2007 (ADAMS Accession No. ML072060413), describes a relief request regarding the Braidwood, Units 1 and 2, RHR heat exchanger nozzle examinations for the second 10-year inspection interval. The staff further noted that even though this 2007 relief request was withdrawn by the applicants letter dated January 23, 2008 (ADAMS Accession No.
ML080240324), the July 25, 2007, letter indicates that UT examinations were performed in September 1998, on a nozzle (1RHR-01-1RHXN1, A HX) of Braidwood, Unit 1, RHR heat exchangers to fulfill the requirements specified in the NRC safety evaluation dated February 22, 1996, to volumetrically inspect one nozzle per unit during the second inservice inspection interval. The applicants 2007 letter also states that no appreciable flaw growth was noted from the 1998 examinations on the examined nozzle of Braidwood, Unit 1.
ENCLOSURE
Issue:
It is unclear to the staff why the applicants response to RAI 4.7.4-1 does not discuss the UT examination results for the Braidwood, Unit 1, RHR heat exchanger nozzle which were obtained in September 1998 as described in the applicants letter dated July 25, 2007. It is also unclear to the staff why the applicants response does not address any results of the UT examinations, which are associated with the applicants fracture mechanics analysis and are required for the RHR heat exchanger nozzles (i.e., a nozzle per unit) as specified in the staffs safety evaluation dated February 29, 1996.
Furthermore, it is unclear to the staff whether the previous examinations of the nozzles, including the 1998 examinations, indicate that any of these flaws grew. In addition, the staff needs clarification on whether the existing flaws are embedded inside the RHR heat exchanger nozzles without exposure to the reactor coolant in order to confirm the absence of environmental effects on flaw growth. The staff also noted that the applicants response did not provide the length of the bounding flaw with a depth of 0.300 inches.
Request:
- 1. Clarify why the applicants response to RAI 4.7.4-1 does not discuss the UT examination results of the Braidwood, Unit 1, RHR heat exchanger nozzle which were obtained in September 1998 as described in the applicants letter dated July 25, 2007.
- 2. Clarify why the applicants response does not address results of the UT examinations, which are associated with the applicants fracture mechanics analysis and are required for the RHR heat exchanger nozzles (i.e., a nozzle per unit) as specified in the staffs safety evaluation dated February 29, 1996.
If all of these UT examinations have not been completed, justify why the applicant does not identify the UT examinations as part of the 10 CFR Part 54.21(c)(1)(iii) aging management basis associated with the applicants fracture mechanics analysis.
- 3. Provide additional information to confirm whether the previous examinations of the nozzles, including the 1998 examinations, indicate that any of these flaws grew. As part of the response, define no appreciable flaw growth which was mentioned in the Byron and Braidwood letter dated July 25, 2007.
- 4. Clarify whether the existing flaws are embedded inside the RHR heat exchanger nozzles without exposure to the reactor coolant in order to confirm the absence of environmental effects on flaw growth. In addition, describe the length of the bounding flaw in comparison with the inner diameter of the nozzle.
RAI 3.1.1.81-1a Applicability:
Byron and Braidwood
Background:
By letter dated March 28, 2014, the applicant responded to RAI 3.1.1.81-1, which addressed LRA item 3.1.1-81. This LRA item states that the Water Chemistry program and One-Time Inspection program are used to manage cracking due to stress-corrosion cracking (SCC) for stainless steel pressurizer spray heads exposed to reactor coolant. LRA item 3.1.1-81 corresponds to NUREG-1800, Standard Review Plan for Review of License Renewal Applications for Nuclear Power Plants Table 3.1-1, item 81, which contains GALL Report item IV.C2.RP-41.
Issue:
During its review of the applicants response and related information, the staff noted that LRA Table 3.1.2-1 for the reactor coolant system does not include a specific aging management review (AMR) line item for GALL Report item IV.C2.RP-41, which manages cracking due to SCC of stainless steel pressurizer spray heads in accordance with LRA item 3.1.1-81.
Therefore, the staff cannot determine how the applicant will manage cracking due to SCC of pressurizer spray heads.
Request:
Clarify why LRA Table 3.1.2-1 does not include a specific AMR line item which manages cracking due to SCC of stainless steel pressurizer spray heads using LRA item 3.1.1-81.
Alternatively, revise the LRA to identify an AMR line item which is associated with LRA item 3.1.1-81 to manage cracking due to SCC for these components.