ML072841176
| ML072841176 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 10/26/2007 |
| From: | Peter Bamford NRC/NRR/ADRO/DORL/LPLI-2 |
| To: | Crane C Exelon Generation Co, Exelon Nuclear |
| Bamford, Peter J., NRR/DORL 415-2833 | |
| References | |
| TAC MD5200, TAC MD5201 | |
| Download: ML072841176 (7) | |
Text
October 26, 2007 Mr. Christopher M. Crane President and Chief Nuclear Officer Exelon Nuclear Exelon Generation Company, LLC 200 Exelon Way, KSA 3-E Kennett Square, PA 19348
SUBJECT:
LIMERICK GENERATING STATION UNIT NOS. 1 AND 2 - REQUEST FOR ADDITIONAL INFORMATION REGARDING PROPOSED THIRD INSERVICE INSPECTION INTERVAL RELIEF REQUESTS (TAC NOS. MD5200 AND MD5201)
Dear Mr. Crane:
By letter dated March 6, 2007, (Agencywide Documents Access and Management System Accession No. ML070660108) Exelon Generation Company, LLC, submitted a set of Relief Requests associated with the Third Inservice Inspection Interval for Limerick Generating Station, Unit Nos. 1 and 2.
The U.S. Nuclear Regulatory Commission has determined that a response to the enclosed Request for Additional Information (RAI) is necessary in order for the staff to complete its review.
The questions in the enclosure were sent to Mr. Thomas Loomis of your staff via electronic transmission in draft form on September 13, 2007, and October 10, 2007. The draft RAIs 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. During a telephone call with Mr. Loomis on October 10, 2007, a response date of November 9, 2007, was agreed upon.
Please contact me at 301-415-2833 if you have any questions.
Sincerely,
/ra/
Peter J. Bamford, Project Manager Plant Licensing Branch 1-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-352 and 50-353
Enclosure:
As stated cc w/encl: See next page
Limerick Generating Station, Unit Nos. 1 and 2 cc:
Christopher Mudrick Site Vice President Limerick Generating Station Exelon Generation Company, LLC P.O. Box 2300 Sanatoga, PA 19464 Ed Callan Plant Manager Limerick Generating Station Exelon Generation Company, LLC P.O. Box 2300 Sanatoga, PA 19464 Regulatory Assurance Manager - Limerick Exelon Generation Company, LLC P.O. Box 2300 Sanatoga, PA 19464 Vice President - Operations, Mid-Atlantic Exelon Generation Company, LLC 200 Exelon Way, KSA 3-N Kennett Square, PA 19348 Vice President Licensing and Regulatory Affairs Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555 Director Licensing and Regulatory Affairs Exelon Generation Company, LLC 200 Exelon Way, KSA 3-E Kennett Square, PA 19348 Manager Licensing Limerick Generating Station Exelon Generation Company, LLC 200 Exelon Way, KSA 3-E Kennett Square, PA 19348 Correspondence Control Desk Exelon Generation Company, LLC P.O. Box 160 Kennett Square, PA 19348 Regional Administrator, Region I U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 Senior Resident Inspector U.S. Nuclear Regulatory Commission Limerick Generating Station P.O. Box 596 Pottstown, PA 19464 Library U.S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406 Director, Bureau of Radiation Protection Pennsylvania Dept. of Environmental Protection Rachel Carson State Office Building P.O. Box 8469 Harrisburg, PA 17105-8469 Chairman Board of Supervisors of Limerick Township 646 West Ridge Pike Linfield, PA 19468 Dr. Judith Johnsrud National Energy Committee Sierra Club 433 Orlando Avenue State College, PA 16803 J. Bradley Fewell, Esquire Associate General Counsel Exelon Generating Company, LLC 4300 Winfield Road Warrenville, IL 60555 Mr. Christopher M. Crane President & Chief Nuclear Officer Exelon Generating Company, LLC 4300 Winfield Road Warrenville, IL 60555
October 26, 2007 Mr. Christopher M. Crane President and Chief Nuclear Officer Exelon Nuclear Exelon Generation Company, LLC 200 Exelon Way, KSA 3-E Kennett Square, PA 19348
SUBJECT:
LIMERICK GENERATING STATION UNIT NOS. 1 AND 2 - REQUEST FOR ADDITIONAL INFORMATION REGARDING PROPOSED THIRD INSERVICE INSPECTION INTERVAL RELIEF REQUESTS (TAC NOS. MD5200 AND MD5201)
Dear Mr. Crane:
By letter dated March 6, 2007, (Agencywide Documents Access and Management System Accession No. ML070660108) Exelon Generation Company, LLC, submitted a set of Relief Requests associated with the Third Inservice Inspection Interval for Limerick Generating Station, Unit Nos. 1 and 2.
The U.S. Nuclear Regulatory Commission has determined that a response to the enclosed Request for Additional Information (RAI) is necessary in order for the staff to complete its review.
The questions in the enclosure were sent to Mr. Thomas Loomis of your staff via electronic transmission in draft form on September 13, 2007, and October 10, 2007. The draft RAIs 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. During a telephone call with Mr. Loomis on October 10, 2007, a response date of November 9, 2007, was agreed upon.
Please contact me at 301-415-2833 if you have any questions.
Sincerely,
/ra/
Peter J. Bamford, Project Manager Plant Licensing Branch I-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-352 and 50-353
Enclosure:
As stated cc w/encl: See next page DISTRIBUTION:
PUBLIC LPL1-2 R/F RidsNrrPMPBamford RidsNrrLAABaxter RidsOgcRp RidsAcrsAcnwMailCenter RidsNrrDorlLpl1-2 RidsRgn1MailCenter RidsNrrDorlDpr RidsNrrDciCvib RidsNrrDciCpnb RidsNrrDciCptb RidsNrrDraApla TMcLellan, NRR TLupold, NRR GBedi, NRR SDinsmore, NRR DChung, NRR Accession Number: ML072841176
- Concurrence provided by memo
- Concurrence provided by email OFFICE LPL1-2/PM LPL1-2/LA CVIB/BC CPND/BC CPTB/BC APLA/BC LPL1-2/BC NAME PBamford ABaxter MMitchell*
TChan*
JMcHale**
MRubin*
HChernoff DATE 10/17/2007 10/17/2007 07/11/2007 09/06/2007 07/10/2007 09/24/2007 10/26/2007 Official Record Copy
ENCLOSURE 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 Inspection (ISI) interval for Limerick Generating Station (LGS), Units 1 and 2.
The U.S. Nuclear Regulatory Commission (NRC) staff has been reviewing the submittal and has determined that additional information is needed to complete its review.
Relief Request I3R-02:
Background:
Relief Request I3R-02, dated March 6, 2007, states that in lieu of the evaluation and sample expansion requirements in Electric Power Research Institute (EPRI) TR-112657, Section 3.6.6.2, RISI Selected Evaluations, LGS 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, LGS 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 not 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, flow-assisted corrosion, microbiological corrosion, 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.
Based on this background discussion the NRC staff has the following questions:
- 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.
Is your proposed RI-ISI program the same program as the prior program authorized by the NRC via letter dated March 3, 2003, ADAMS Accession No. ML030620491, (i.e., are the number and locations of the exams the same or have they changed)? 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.
- 7.
In Section 4.0 of Relief Request I3R-02, you state that, the original risk impact assessment is not a necessary element of the implementing process and is not required to be continually updated.
The risk assessment need not be continually updated. LGS is, however, requesting to use a risk-informed alternative in accordance with Title 10 of the Code of Federal Regulations 50.55a(a)(3)(i) for the third ISI interval that began on February 1, 2007, and that is based on Electric Power Research Institute (EPRI) TR-112657. A vital element of the NRC staffs conclusion that your proposed alternative satisfies the EPRI guidelines and provides an acceptable level of quality and safety is the evaluation of the change in risk between the ASME inspection program and your proposed program. The staff requests an estimate of the change in risk between the ASME ISI program in place at your facility prior to the implementation of the first RI-ISI program, and the RI-ISI program that you are proposing for the third ISI interval. Please provide this information. The estimate should include all changes to the facility and to the Probabilistic Risk Assessment models that might affect the change in risk estimate.
Request for Additional Information:
- 1.
Page two of RR I3R-05, 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 LGS 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 LGS Technical Specification (TS) Testing Program.
- 2.
Page two of RR I3R-05, 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 LGS, snubbers are tested by an in-place or bench test, because TS 3/4.7.4 does not specify this.
- 4.
Snubbers are tested in defined test groups using either a 10 percent testing plan or the 37 Testing Sample Plan. 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 10 CFR 50.55a(g)(5)(iii), from the ASME Code required volumetric examination of essentially 100 percent 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. LGS, Units 1 and 2 each have two RHR heat exchangers. Are exams of all four heat exchangers planned to distribute the examinations in order to meet the ASME Code required volumetric examination of essentially 100 percent 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 percent 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.
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, provide a detailed evaluation and justification of the effect of the proposed ILRT extension on the level of quality 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. TS 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.