ML072560592
| ML072560592 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 09/13/2007 |
| From: | Peter Bamford NRC/NRR/ADRO/DORL/LPLI-2 |
| To: | Chernoff H NRC/NRR/ADRO/DORL/LPLI-2 |
| Bamford, Peter J., NRR/DORL 415-2833 | |
| References | |
| TAC MD5200, TAC MD5201 | |
| Download: ML072560592 (6) | |
Text
September 13, 2007 MEMORANDUM TO: Harold K. Chernoff, Chief Plant Licensing Branch I-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation FROM:
Peter Bamford, Project Manager /ra/
Plant Licensing Branch I-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation
SUBJECT:
LIMERICK GENERATING STATION, UNIT NOS 1 AND 2 -
ELECTRONIC TRANSMISSION, DRAFT REQUEST FOR ADDITIONAL INFORMATION REGARDING THIRD INTERVAL INSERVICE INSPECTION RELIEF REQUESTS (TAC NOS. MD5200 AND MD5201)
The attached draft request for additional information (RAI) was sent by electronic transmission on September 13, 2007, to Mr. Thomas Loomis, at Exelon Generation Company, LLC (Exelon). This draft RAI was transmitted to facilitate the technical review being conducted by the Nuclear Regulatory Commission (NRC) staff and to support a conference call with Exelon in order to clarify certain items in the licensee=s submittal. The draft RAI is related to Exelon=s submittal dated March 6, 2007, regarding nine relief requests associated with the third inservice inspection interval. The draft questions were sent to ensure that the questions were understandable, the regulatory basis for the questions was clear, and to determine if the information was previously docketed. Additionally, review of the draft RAI would allow Exelon to determine and agree upon a schedule to respond to the RAI. This memorandum and the attachment do not represent an NRC staff position.
Docket Nos. 50-352 and 50-353
Enclosure:
As stated
September 13, 2007 MEMORANDUM TO: Harold K. Chernoff, Chief Plant Licensing Branch I-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation FROM:
Peter Bamford, Project Manager /ra/
Plant Licensing Branch I-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation
SUBJECT:
LIMERICK GENERATING STATION, UNIT NOS 1 AND 2 -
ELECTRONIC TRANSMISSION, DRAFT REQUEST FOR ADDITIONAL INFORMATION REGARDING THIRD INTERVAL INSERVICE INSPECTION RELIEF REQUESTS (TAC NOS. MD5200 AND MD5201)
The attached draft request for additional information (RAI) was sent by electronic transmission on September 13, 2007, to Mr. Thomas Loomis, at Exelon Generation Company, LLC (Exelon). This draft RAI was transmitted to facilitate the technical review being conducted by the Nuclear Regulatory Commission (NRC) staff and to support a conference call with Exelon in order to clarify certain items in the licensee=s submittal. The draft RAI is related to Exelon=s submittal dated March 6, 2007, regarding nine relief requests associated with the third inservice inspection interval. The draft questions were sent to ensure that the questions were understandable, the regulatory basis for the questions was clear, and to determine if the information was previously docketed. Additionally, review of the draft RAI would allow Exelon to determine and agree upon a schedule to respond to the RAI. This memorandum and the attachment do not represent an NRC staff position.
Docket Nos. 50-352 and 50-353
Enclosure:
As stated DISTRIBUTION:
Public RidsNrrPMPBamford LPL1-2 R/F GBedi, NRR TLupold, NRR TMcLellan, NRR Accession No.: ML072560592
- via memorandum
- via email OFFICE LPL1-2/PM CPNB/BC CVIB/BC CPTB/BC NAME PBamford TChan*
MMitchell*
JMcHale**
DATE 9/13/2007 09/06/2007 07/11/2007 07/10/2007 OFFICIAL RECORD COPY
Enclosure DRAFT REQUEST FOR ADDITIONAL INFORMATION REGARDING RELIEF REQUESTS ASSOCIATED WITH THE THIRD INSERVICE INSPECTION INTERVAL LIMERICK GENERATING STATION, UNIT NOS. 1 AND 2 DOCKET NOS. 50-352 AND 50-353 By letter dated March 6, 2007 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML070660108), Exelon Generation Company, LLC, submitted a set of relief requests associated with the Third Inservice Insepection (ISI) interval for Limerick Generating Station (LGS), Units 1 and 2.
The Nuclear Regulatory Commission (NRC) Staff has been reviewing the submittal and has determined that additional information is needed to complete its review.
Relief Request 13R-02:
Background:
Relief Request I3R-02 states that in lieu of the evaluation and sample expansion requirements in Electric Power Research Institute (EPRI) TR-112657, Section 3.6.6.2, Limerick Generating Station will utilize the requirements of Subarticle - 2430, Additional Examinations contained in Code Case N-578-1. `The alternative criteria for additional examinations contained in Code Case N-578-1 provide a more refined methodology for implementing necessary additional examinations.
Relief Request I3R-02 also states that to supplement the requirements of EPRI TR-112657, Table 4-1, Summary of Degradation-Specific Inspection Requirements and Examination Methods, Limerick Generating Station will utilize the provisions listed in Table 1, Examination Category R-A, Risk-Informed Piping Examinations contained in Code Case N-578-1.
The NRC staff notes that Regulatory Guide (RG) 1.193 ASME Code Cases Not Approved for Use, dated August 2005, lists the code cases that the NRC has determined to not be acceptable for use on a generic basis. Code Case N-578-1 is listed in Table 2 Unacceptable Section XI Code Cases of RG 1.193. The summary given in Table 2 of RG 1.193 states in regards to Code Case N-578-1 that:
(1)
The Code Case does not address inspection strategy for existing augmented and other inspection programs such as intergranular stress corrosion cracking (IGSCC), flow-assisted corrosion (FAC), microbiological corrosion (MIC), and pitting.
(2)
The Code Case does not provide system-level guidelines for change in risk evaluation to ensure that the risk from individual system failures will be kept small and dominant risk contributors will not be created.
Request for Additional Information:
- 1.
It is not clear what is meant by a more refined methodology for implementing additional examinations. How do the alternative criteria for additional examinations contained in Code Case N-578-1 provide a more refined methodology?
- 2.
Please verify that any additional examinations required due to the identification of flaws or relevant conditions will be conducted during the current outage.
- 3.
Discuss what examination methods will be performed for each degradation mechanism.
What volumes will be examined and what techniques will be used?
- 4.
Please describe how volumetric examinations will be performed. Will volumetric examinations include the volume required for American Society of Mechanical Engineers (ASME)Section XI examinations? Will ASME Section XI, Appendix VIII qualified examiners and procedures be used for all volumetric exams? Will the examination volume be scanned for both axial and transverse indications for all exams?
- 5.
How will dissimilar metal welds be addressed? Discuss in detail the technical basis for including alloy 600 pressure-retaining dissimilar metal welds in your risk-informed inservice inspection (RI-ISI), rather than a separate augmented program to the RI-ISI program.
- 6.
Provide information regarding: examinations/system/components/degradation mechanisms/class, etc. similar to that provided in Attachment 1 of the Callaway submittal dated March 28, 2006 (ADAMS Accession No. ML061010704). The information should show a summary of the changes in inspections from the ASME Section XI program and changes from the previous RI-ISI program to the proposed RI-ISI program.
Request for Additional Information:
- 1.
On Page I3R-05-2, second paragraph, sixth line states that The Technical Specifications functional testing program is based on the ASME/ANSI OMc-1990 Addenda to the ASME/ANSI OM-1987 Edition Part 4. The relief request states that the Limerick is using ASME Section XI, 2001 Edition through the 2003 Addenda. ASME Section XI, requires the use of ASME/ANSI OM-1987 Edition Part 4 with OMa 1988 Addenda (Ref. Table IWA-1600-1). Also, the NRC never endorsed OMc-1990 Addenda to OM-4 for use. Therefore, please provide the basis for using the OMc-1990 Addenda as the basis for the Limerick Technical Specification (TS) Testing Program.
- 2.
On Page I3R-05-2, fifth paragraph, states that The examinations are performed by qualified personnel and meet the intent of the inspections and tests of ASME Section XI.
Please provide justification for this statement and explain how the TS 3/4.7.4 visual examination method is equivalent to the VT-3 visual examination method described in IWA-2213.
- 3.
OM-4, Paragraph 3.2.1.1, Operability Test, states that snubber operational readiness shall be tested by either an in-place or bench test. Please verify that at Limerick, snubbers are tested by an in-place or bench test, because TS 3/4.7.4 does not specify this.
- 4.
The 37 Testing Sample Plan: OM-4, Paragraph 3.2.3.2(b) states that for any snubber(s) determined to be unacceptable as a result of testing, an additional random sample of at least one-half the size of the initial sample lot shall be tested. Explain how the requirements of Section 3.2.3.2(b) will be met, if the 37 testing sample plan is used.
Request for Additional Information:
- 1.
For Relief Request I3R-06, Revision 0, relief is requested pursuant to Title 10 Code of Federal Regulations (10 CFR) 50.55a(g)(5)(iii), from the ASME Code required volumetric examination of essentially 100% of the weld length on the basis that conformance to the ASME Code is impractical.
(a.)
Provide the following residual heat removal (RHR) heat exchanger drawings as referenced in Relief Request I3R-06: XI-1E-205 (LGS, Unit 1) and XI-2E-205 (LGS, Unit 2);
(b.)
In the Applicable Code Requirement section of RR I3R-06, ASME Code Figure IWC-2500-1 for circumferential welds is referenced. Identify whether the applicable weld configuration is Figure IWC-2500-1(a) or (b) or (c);
(c.)
ASME Code,Section XI, Table IWC-2500-1, Examination Category C-A, Item C1.10, Note 3 states that in the case of multiple vessels of similar design, size, and service (such as steam generators, heat exchangers), the required examinations may be limited to one vessel or distributed among the vessels. Since LGS, Units 1 and 2 each have two RHR heat exchangers, has the licensee considered the alternative of examining the second RHR heat exchanger of each unit to distribute the examinations in order to meet the ASME Code required volumetric examination of essentially 100% of the weld length?
Request for Additional Information:
- 1.
For Relief Request I3R-07, Revision 0, the licensee requested relief pursuant to 10 CFR 50.55a(g)(5)(iii), from the ASME Code requirements of 100% surface examination of the RHR heat exchanger and core spray pump casting welds on the basis that conformance with the ASME Code requirements are impractical.
(a.)
Provide the following pump drawings as referenced in Relief Request I3R-07:
XI-1P-202 and XI-1P-206 (LGS, Unit 1), XI-2P-202 and XI-2P-206 (LGS, Unit 2)
(b.)
Clarify the pump designations regarding 1(2) and what pumps are assigned to LGS, Units 1 and 2 and to what systems.
Request for Additional Information:
None Relief Request (RR) 13R-09, 13R-10, 13R-11, and 13R-12:
Request for Additional Information:
- 1.
The NRC staff understands that LGS, Units 1 and 2 is proposing to extend its Integrated Leak Rate Test (ILRT) interval from 10 to 15 years in accordance with the submittal dated February 20, 2007 (ADAMS Accession No. ML070530296). Based on the proposed new ILRT frequency, discuss any impact on the level of qualify and safety for relief requests I3R-09 and I3R-10.
- 2.
For the components of relief requests I3R-09, I3R-10, I3R-11, and I3R-12, please identify any tests conducted, e.g. technical specification surveillance tests, which affect internal pressure other than the ILRT and local leak rate tests, the frequency conducted, the internal pressure achieved, and the feasibility of conducting a system leak test concurrent with the test.
- 3.
Please provide drawings referenced in relief requests I3R-09, I3R-10, I3R-11, and I3R-12.