ML070660108
| ML070660108 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 03/06/2007 |
| From: | Cowan P Exelon Nuclear |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML070660108 (35) | |
Text
Exelon Nuclear www.exeloncorp.com 200 Exelon Way Kennett Square, PA 19348 10 CFR 50.55a March 6,2007 US. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 Limerick Generating Station, Units 1 and 2 Facility Operating License Nos. NPF-39 and NPF-85 NRC Docket Nos. 50-352 and 50-353
Subject:
Submittal of Relief Requests Associated with the Third Inservice Inspection (ISI) Interval Attached for your review are relief requests associated with the Third Inservice Inspection (ISI)
Interval for Limerick Generating Station, Units 1 and 2. The third interval of the LGS, Units 1 and 2 IS1 program complies with the 2001 Edition through 2003 Addenda of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code. The third IS1 interval began on February 1,2007, and will conclude January 31,2017, for Limerick Generating Station, Units 1 and 2. On January 31, 2007, the latest edition and addenda of the code incorporated by reference in 10CFR50.!55a(b)(2) of the regulation was the 2001 Edition through the 2003 Addenda. We request your approval by March 6,2008.
Please note that all the attached relief requests were previously approved as part of the second IS1 interval for LGS, Units 1 and 2 except for 13R-08.
Should you have any questions concerning this letter, please contact Tom Loomis at (610) 765-5510.
Sincerely, Pamela B. Cowan Director - Licensing & Regulatory Affairs Exelon Generation Company, LLC
Attachment:
- 1) Relief Requests Associated with the Third Ten-Year interval for Limerick Generating Station, Units 1 and 2 cc: S. J. Collins, Regional Administrator, Region I, USNRC S. Hansell, USNRC Senior Resident Inspector, LGS J. Shea, Project Manager [LGS] USNRC
Relief Requests Associated with the Third Ten-Year Interval for Limerick Generating Station, Units 1 and 2 13R-02 13R-05 13R-06 13R-07 13R-08 13R-09 13R-10 13R-11 l3R-12
ISI Program Plan Limerick Generating Station Units 1 & 2, Third Interval 10CFR50.55a RELIEF REQUEST I3R-02 Revision 0 (Page 1 of 6)
Request for Relief for Alternate Risk-Informed Selection and Examination Criteria for Examination Category B-F, B-J, C-F-1, and C-F-2 Pressure Retaining Piping Welds In Accordance with 10CFR50.55a(a)(3)(i) 1.0 ASME CODE COMPONENTS AFFECTED:
Code Class: 1 and 2
Reference:
Table IWB-2500-1, Table IWC-2500-1 Examination Category: B-F, B-J, C-F-1, and C-F-2 Item Number: B5.10, B5.20, B9.11, B9.21, B9.31, B9.32, B9.40, C5.11, C5.51, and C5.81
Description:
Alternate Risk-Informed Selection and Examination Criteria for Examination Category B-F, B-J, C-F-1, and C-F-2 Pressure Retaining Piping Welds Component Number: Unit 1 and Unit 2 Pressure Retaining Piping 2.0 APPLICABLE CODE EDITION AND ADDENDA:
The Inservice Inspection program is based on the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code,Section XI, 2001 Edition through the 2003 Addenda.
3.0 APPLICABLE CODE REQUIREMENT:
The following Code requirements are paraphrased from the 2001 Edition through the 2003 Addenda of ASME Section XI.
Table IWB-2500-1, Examination Category B-F, requires volumetric and surface examinations on all welds for Item B5.10 and surface examinations for all welds for Item B5.20.
Table IWB-2500-1, Examination Category B-J, requires volumetric and/or surface examinations on a sample of welds for Items B9.11, B9.21, B9.31, B9.32, and B9.40.
The weld population selected for inspection includes the following:
- 1. All terminal ends in each pipe or branch run connected to vessels.
- 2. All terminal ends and joints in each pipe or branch run connected to other components where the stress levels exceed either of the following limits under loads associated with specific seismic events and operational conditions:
ISI Program Plan Limerick Generating Station Units 1 & 2, Third Interval 10CFR50.55a RELIEF REQUEST I3R-02 Revision 0 (Page 2 of 6)
- a. primary plus secondary stress intensity range of 2.4Sm for ferritic steel and austenitic steel.
- b. cumulative usage factor U of 0.4.
- 3. All dissimilar metal welds not covered under Examination Category B-F.
- 4. Additional piping welds so that the total number of circumferential butt welds, branch connections, or socket welds selected for examination equals 25% of the circumferential butt welds, branch connection, or socket welds in the reactor coolant piping system. This total does not include welds exempted by IWB-1220.
Table IWC-2500-1, Examination Categories C-F-1 and C-F-2 require volumetric and/or surface examinations on a sample of welds for Items C5.11, C5.51, and C5.81. The weld population selected for inspection includes the following:
- 1. Welds selected for examination shall include 7.5%, but not less than 28 welds, of all dissimilar metal, austenitic stainless steel and high alloy welds (Examination Category C-F-1) or of all carbon and low alloy steel welds (Examination Category C-F-2) not exempted by IWC-1220. (Some welds not exempted by IWC-1220 are not required to be nondestructively examined per Examination Categories C-F-1 and C-F-2. These welds, however, shall be included in the total weld count to which the 7.5% sampling rate is applied.) The examinations shall be distributed as follows:
- a. the examinations shall be distributed among the Class 2 systems prorated, to the degree practicable, on the number of nonexempt dissimilar metal, austenitic stainless steel and high alloy welds (Examination Category C-F-1) or carbon and low alloy welds (Examination Category C-F-2) in each system;
- b. within a system, the examinations shall be distributed among terminal ends, dissimilar metal welds, and structural discontinuities prorated, to the degree practicable, on the number of nonexempt terminal ends, dissimilar metal welds, and structural discontinuities in the system; and
- c. within each system, examinations shall be distributed between line sizes prorated to the degree practicable.
ISI Program Plan Limerick Generating Station Units 1 & 2, Third Interval 10CFR50.55a RELIEF REQUEST I3R-02 Revision 0 (Page 3 of 6) 4.0 REASON FOR REQUEST:
Pursuant to 10CFR50.55a(a)(3)(i), relief is requested on the basis that the proposed alternative utilizing Reference 1 along with two enhancements from Reference 4 will provide an acceptable level of quality and safety.
As stated in Safety Evaluation Report Related to EPRI Risk-Informed Inservice Inspection Evaluation Procedure (EPRI TR-112657, Revision B, July 1999) (Reference 2):
"The staff concludes that the proposed RISI program as described in EPRI TR-112657, Revision B, is a sound technical approach and will provide an acceptable level of quality and safety pursuant to 10CFR50.55a for the proposed alternative to the piping ISI requirements with regard to the number of locations, locations of inspections, and methods of inspection."
The initial Limerick Generating Station RISI Program was submitted during the Second Period of the Second Interval for Unit 1 and during the First Period of the Second Interval for Unit 2. This initial RISI program was developed in accordance with EPRI TR-112657, Revision B-A, as supplemented by Code Case N-578-1. The program was approved for use by the USNRC via a Safety Evaluation as transmitted to Exelon (Reference 5).
The transition from the 1989 Edition to the 2001 Edition through the 2003 Addenda of ASME Section XI for Limerick Generating Stations Third Interval does not impact the currently approved Risk-Informed ISI evaluation process used in the Second Interval, and the requirements of the new Code Edition/Addenda will be implemented as detailed in the Limerick Generating Station ISI Program Plan.
The Risk Impact Assessment completed as part of the original baseline RISI Program was an implementation/transition check on the initial impact of converting from a traditional ASME Section XI program to the new RISI methodology. For the Third Interval ISI update, there is no transition occurring between two different methodologies, but rather, the currently approved RISI methodology and evaluation will be maintained for the new interval. As such, the original risk impact assessment is not a necessary element of the implementing process and is not required to be continually updated.
As an added measure of assurance, any new systems, portions of systems, or components being included in the RISI Program for the Third Interval will be added to the Risk Impact Assessment performed during the previous interval. These components will be addressed within the evaluation at the start of the new interval to assure that the new Third Interval RISI element selection provides an acceptable overall change-in-risk when I3R-02-3
ISI Program Plan Limerick Generating Station Units 1 & 2, Third Interval 10CFR50.55a RELIEF REQUEST I3R-02 Revision 0 (Page 4 of 6) compared to the old ASME Section XI population of exams which existed prior to the implementation of the first RISI Program.
The actual evaluation and ranking procedure including the Consequence Evaluation and Degradation Mechanism Assessment processes of the currently approved (Reference 5)
RISI Program remain unchanged and are continually applied to maintain the Risk Categorization and Element Selection methods of EPRI TR-112657, Revision B-A.
These portions of the RISI Program are reevaluated as major revisions of the site PRA occur and modifications to plant configuration are made. The Consequence Evaluation, Degradation Mechanism Assessment, Risk Ranking, and Element Selection steps encompass the complete living program process applied under the Limerick Generating Station RISI Program.
5.0 PROPOSED ALTERNATIVE AND BASIS FOR USE:
The proposed alternative originally implemented in the risk informed inservice inspection plan, Limerick Generating Station Units 1 and 2 (Reference 3), along with the two enhancements noted below, provide an acceptable level of quality and safety as required by 10CFR50.55a(a)(3)(i). This original program along with these same two enhancements is currently approved for Limerick Generating Stations Second Inservice Inspection Interval as documented in Reference 5.
The Third Interval RISI Program will be a continuation of the current application and will continue to be a living program as described in the Reason For Request section of this relief request. No changes to the evaluation methodology as currently implemented under EPRI TR-112657, Revision B-A, are required as part of this interval update. The following two enhancements will continue to be implemented.
In lieu of the evaluation and sample expansion requirements in Section 3.6.6.2, "RISI Selected Examinations" of EPRI TR-112657, Limerick Generating Station will utilize the requirements of Subarticle -2430, "Additional Examinations" contained in Code Case N-578-1 (Reference 4). The alternative criteria for additional examinations contained in Code Case N-578-1 provides a more refined methodology for implementing necessary additional examinations.
To supplement the requirements listed in Table 4-1, "Summary of Degradation-Specific Inspection Requirements and Examination Methods" of EPRI TR-112657, 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 (Reference 4). To implement Note 10 of this table, paragraphs and figures from the 2001 Edition through the 2003 Addenda of ASME Section XI (Limerick Generating Stations Code of record for the Third Interval) will be utilized which parallel those referenced in the Code Case for the I3R-02-4
ISI Program Plan Limerick Generating Station Units 1 & 2, Third Interval 10CFR50.55a RELIEF REQUEST I3R-02 Revision 0 (Page 5 of 6) 1989 Edition. Table 1 of Code Case N-578-1 will be used as it provides a detailed breakdown for examination method and categorization of parts to be examined.
The Limerick Generating Station RISI Program, as developed in accordance with EPRI TR-112657, Rev. B-A (Reference 1), requires that 25% of the elements that are categorized as High risk (i.e., Risk Category 1, 2, and 3) and 10% of the elements that are categorized as Medium risk (i.e., Risk Categories 4 and 5) be selected for inspection. For this application, the guidance for the examination volume for a given degradation mechanism is provided by the EPRI TR-112657 while the guidance for the examination method and categorization of parts to be examined are provided by the EPRI TR-112657 as supplemented by Code Case N-578-1.
In addition to this risk-informed evaluation, selection, and examination procedure, all ASME Section XI piping components, regardless of risk classification, will continue to receive Code required pressure testing as part of the current ASME Section XI program.
VT-2 visual examinations are scheduled in accordance with the Limerick Generating Station pressure testing program, which remains unaffected by the RISI program.
6.0 DURATION OF PROPOSED ALTERNATIVE:
Relief is requested for the Third Ten-Year Inspection Interval for Limerick Generating Station Units 1 and 2. The third ISI interval began on February 1, 2007 and will conclude January 31, 2017 for Limerick Generating Station, Units 1 and 2.
7.0 PRECEDENTS
Similar relief requests have been approved for:
Limerick Generating Station Second Inspection Interval Relief Request RR-32 was authorized per SER dated March 3, 2003. The Third Inspection Interval Relief Request will utilize the same RISI methodology that was previously approved in the Second Inspection Interval.
Susquehanna Steam Electric Station Third Inspection Interval Relief Request I3R-01 was authorized per SER dated July 28, 2005.
Dresden Station Fourth Inspection Interval Relief Request I4R-02 was authorized per SER dated September 4, 2003.
Quad Cities Station Fourth Inspection Interval Relief Request I4R-02 was authorized per SER dated January 28, 2004.
ISI Program Plan Limerick Generating Station Units 1 & 2, Third Interval 10CFR50.55a RELIEF REQUEST I3R-02 Revision 0 (Page 6 of 6)
8.0 REFERENCES
- 1) Electric Power Research Institute (EPRI) Topical Report (TR) 112657 Rev. B-A, "Revised Risk-Informed Inservice Inspection Evaluation Procedure", December 1999
- 2) W. H. Bateman (USNRC) to G. L. Vine (EPRI) letter dated October 28, 1999 transmitting "Safety Evaluation Report Related to EPRI Risk-Informed Inservice Inspection Evaluation Procedure (EPRI TR-112657, Revision B, July 1999)"
- 3) Initial Risk-Informed Inservice Inspection Evaluation - Limerick Generating Station Units 1 and 2, dated March 15, 2002
- 4) American Society of Mechanical Engineers (ASME) Code Case N-578-1, "Risk-Informed Requirements for Class 1, 2, or 3 Piping, Method B"
- 5) James W. Clifford (USNRC) to John L. Skolds (Exelon) letter dated March 3, 2003 transmitting the Limerick Generating Station, Units 1 and 2 - American Society of Mechanical Engineers Boiler and Pressure Vessel Code - Relief for Risk-Informed Inservice Inspection of Piping (TAC Nos. MB4633 and MB4634)
ISI Program Plan Limerick Generating Station Units 1 & 2, Third Interval 10CFR50.55a RELIEF REQUEST I3R-05 Revision 0 (Page 1 of 3)
Request for Relief for ISI Snubbers Included in the Technical Specifications Snubber Visual Examination and Functional Testing Program In Accordance with 10CFR50.55a(a)(3)(i) 1.0 ASME CODE COMPONENTS AFFECTED:
Code Class: 1, 2, and 3
Reference:
IWF-5200(a) and IWF-5300(a)
IWF-5200(b) and IWF-5300(b)
Examination Category: N/A Item Number: N/A
Description:
ISI Snubbers Included in the Technical Specifications Snubber Visual Examination and Functional Testing Program Component Number: Various components on Unit 1 and Unit 2 2.0 APPLICABLE CODE EDITION AND ADDENDA:
The Inservice Inspection program is based on the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code,Section XI, 2001 Edition through the 2003 Addenda.
3.0 APPLICABLE CODE REQUIREMENT:
The following Code requirements are paraphrased from the 2001 Edition through the 2003 Addenda of ASME Section XI.
Paragraphs IWF-5200(a) and IWF-5300(a) require Preservice and Inservice examinations to be performed in accordance with ASME/ANSI OM, Part 4, using the VT-3 visual examination method described in IWA-2213. Paragraphs IWF-5200(b) and IWF-5300(b) require Preservice and Inservice tests to be performed in accordance with ASME/ANSI OM, Part 4. Table IWA-1600-1 specifies use of the 1987 Edition, through the OMa-1988 Addenda of ASME/ANSI OM, Part 4.
4.0 REASON FOR REQUEST:
Pursuant to 10CFR50.55a(a)(3)(i), relief is requested on the basis that the proposed alternative will provide an acceptable level of quality and safety.
There are approximately 1100 and 656 safety related snubbers at Limerick Generating Station Units 1 and 2, respectively. The overlap of the visual examination program required I3R-05-1
ISI Program Plan Limerick Generating Station Units 1 & 2, Third Interval 10CFR50.55a RELIEF REQUEST I3R-05 Revision 0 (Page 2 of 3) by ASME Section XI and the Technical Specifications snubber program for the ISI classified snubbers presents an unnecessary redundancy without a compensating increase in the level of quality and safety.
Limerick Generating Station, Units 1 and 2, Technical Specifications 3/4.7.4 establish the surveillance requirements for snubbers. The Technical Specifications snubber visual examination program requires an inspection population, which includes all safety related snubbers and incorporates the alternate snubber visual examination requirements delineated in USNRC Generic Letter (GL) 90-09, Alternate Requirements for Snubber Visual Inspection Intervals and Corrective Actions. The Technical Specifications functional testing program is based on the ASME /ANSI OMc-1990 Addenda to the ASME/ANSI OM-1987 Edition, Part 4, Examination and Performance Testing of Nuclear Power Plant Dynamic Restraints (Snubbers). As such, the current Limerick Generating Station Technical Specifications snubber program, Section 3/4.7.4, includes a comprehensive program for visual examination and functional testing requirements of safety related snubbers.
The purpose of the Augmented Inspection Program described in the Limerick Generating Station, Units 1 and 2 Technical Specifications 3/4.7.4 is to assure and demonstrate operational readiness and structural integrity of snubbers through testing and examination. The examination criteria for snubbers from pin-connection to pin-connection meet this objective. Therefore, performance of the ASME Section XI examinations on snubber assemblies would be redundant.
Limerick Generating Station, Units 1 and 2, has procedures in place to implement the program as described in the Technical Specifications 3/4.7.4. Corporate procedures ER-AA-330-004, Visual Examination of Snubbers, ER-AA-330-010, Snubber Functional Testing, ER-AA-330-011, Snubber Service Life Monitoring, and Station surveillance test procedures are used to implement the visual examination, functional testing, and service life monitoring requirements for snubbers, as applicable.
The examinations are performed by qualified personnel and meet the intent of the inspections and tests of ASME Section XI. Based on the above discussion, Limerick Generating Station has determined that implementation of the Technical Specifications 3/4.7.4 snubber program for both Units 1 and 2 will assure an acceptable level of quality and safety.
5.0 PROPOSED ALTERNATIVE AND BASIS FOR USE:
The visual examination and functional testing of snubber assemblies from pin-connection to pin-connection at Limerick Generating Station, Units 1 and 2, will be performed in accordance with Technical Specifications 3/4.7.4. These examinations and tests will be performed in lieu of the inspection and testing requirements of IWF-5200(a) and (b) and I3R-05-2
ISI Program Plan Limerick Generating Station Units 1 & 2, Third Interval 10CFR50.55a RELIEF REQUEST I3R-05 Revision 0 (Page 3 of 3)
IWF-5300(a) and (b). The general requirements of Subsection IWA, such as examination methods, personnel qualifications, etc. still apply.
As required by IWF-5200(c) and IWF-5300(c), the examination of snubber integral and nonintegral attachments, including bolting and load pins will be performed in accordance with Subsection IWF.
It should be noted that the examination of snubber welded attachments will be performed in accordance with the ASME Section XI Subsections IWB, IWC, and IWD welded attachment examination requirements (e.g., Examination Categories B-K, C-C, and D-A).
Visual examiners, who are qualified to the applicable rules of ASME Section XI Article IWA-2000, Examination and Inspection, will perform the examinations of the safety related snubbers.
6.0 DURATION OF PROPOSED ALTERNATIVE:
Relief is requested for the Third Ten-Year Inspection Interval for Limerick Generating Station Units 1 and 2. The third ISI interval began on February 1, 2007 and will conclude January 31, 2017 for Limerick Generating Station, Units 1 and 2.
7.0 PRECEDENTS
Similar relief requests have been approved for:
Limerick Generating Station Second Inspection Interval Relief Request RR-04 was authorized per SER dated February 14, 2002. The Third Inspection Interval Relief Request will utilize the same approach that was previously approved in the Second Inspection Interval.
ISI Program Plan Limerick Generating Station Units 1 & 2, Third Interval 10CFR50.55a RELIEF REQUEST I3R-06 Revision 0 (Page 1 of 3)
Request for Relief for Inservice Inspection Impracticality Due to the Limited Volumetric Examination of RHR Heat Exchanger Pressure Retaining Shell Circumferential Welds (Shell-to-Flange Welds)
In Accordance with 10 CFR 50.55a(g)(5)(iii) 1.0 ASME CODE COMPONENTS AFFECTED:
Code Class: 2
Reference:
Table IWC-2500-1 Examination Category: C-A Item Number: C1.10
Description:
Limited Volumetric Examination of RHR Heat Exchanger Pressure Retaining Shell Circumferential Welds (Shell-to-Flange Welds)
Component Number: RHR-HXAR-4 and RHR-HXBR-4 (Unit 1) 2AE-205 SG-1 and 2BE-205 SG-1 (Unit2)
Drawing Number: XI-1E-205 (Unit 1) and XI-2E-205 (Unit 2) 2.0 APPLICABLE CODE EDITION AND ADDENDA:
The Inservice Inspection program is based on the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code,Section XI, 2001 Edition through the 2003 Addenda.
3.0 APPLICABLE CODE REQUIREMENT:
The following Code requirements are paraphrased from the 2001 Edition through the 2003 Addenda of ASME Section XI.
Table IWC-2500-1 states that the heat exchanger shell welds require a volumetric examination in accordance with the examination requirements illustrated in Figure IWC-2500-1.
Per Table IWC-2500-1, examinations are limited to 100% of the pressure retaining shell circumferential welds at gross structural discontinuities of one (1) heat exchanger (or the equivalent of one heat exchanger) during the inservice inspection interval.
ISI Program Plan Limerick Generating Station Units 1 & 2, Third Interval 10CFR50.55a RELIEF REQUEST I3R-06 Revision 0 (Page 2 of 3) 4.0 IMPRACTICALITY OF COMPLIANCE:
Pursuant to 10CFR50.55a(g)(5)(iii), relief is requested on the basis that conformance with these code requirements is impractical as conformance would require extensive structural modifications to the Residual Heat Removal heat exchangers.
Limerick Generating Station Units 1 and 2, each have two (2) Residual Heat Removal heat exchangers. Code Examination Category C-A, Item Number C1.10, requires the volumetric examination of the equivalent of the welds of one heat exchanger per Unit.
Complete ultrasonic examination of the shell to flange weld (on either heat exchanger) is limited due to access restrictions from the flange bolting. Bolting protruding through the vessel flange prohibits completion of the required ultrasonic scanning parallel to the weld. Transverse scans can be performed from the shell side of the weld, thereby providing approximately 87.5% coverage of the Code required volume. The limitations to complete volumetric examinations are also applicable to surface examination techniques. Disassembly of the flange mechanical connection, to facilitate complete examination, is not practical due to significant radiation exposure and significant man hours required for disassembly / re-assembly as well as the potential for creating a leakage path for reactor coolant.
5.0 BURDEN CAUSED BY COMPLIANCE:
Compliance with the applicable Code requirements can only be accomplished by redesigning and refabricating the subject heat exchangers. Based on this, the Code requirements are deemed impractical in accordance with 10CFR50.55a(g)(5)(iii).
6.0 PROPOSED ALTERNATIVE AND BASIS FOR USE:
The Code required volumetric examination for the subject welds in both Limerick Generating Station Units 1 and 2 heat exchangers will be performed to the maximum extent possible based on the obstructions and geometric constraints detailed in the Impracticality Of Compliance section of this relief request. Additionally, a Visual (VT-
- 2) examination during system pressure testing per Examination Category C-H will be performed on the heat exchangers (once during each period) to verify leak tight integrity of these welds.
7.0 DURATION OF PROPOSED ALTERNATIVE:
Relief is requested for the Third Ten-Year Inspection Interval for Limerick Generating Station, Units 1 and 2. The third ISI interval began on February 1, 2007 and will conclude January 31, 2017 for Limerick Generating Station, Units 1 and 2.
ISI Program Plan Limerick Generating Station Units 1 & 2, Third Interval 10CFR50.55a RELIEF REQUEST I3R-06 Revision 0 (Page 3 of 3)
8.0 PRECEDENTS
Similar relief requests have been approved for:
Limerick Generating Station Second Inspection Interval Relief Request RR-06 was authorized per SER dated May 2, 2002. The Third Inspection Interval Relief Request will utilize the same approach that was previously approved in the Second Inspection Interval.
ISI Program Plan Limerick Generating Station Units 1 & 2, Third Interval 10CFR50.55a RELIEF REQUEST I3R-07 Revision 0 (Page 1 of 3)
Request for Relief for Inservice Inspection Impracticality Due to the Examination of Pressure Retaining Welds in Residual Heat Removal and Core Spray Pumps In Accordance with 10CFR50.55a(g)(5)(iii) 1.0 ASME CODE COMPONENTS AFFECTED:
Code Class: 2
Reference:
Table IWC-2500-1 Examination Category: C-G Item Number: C6.10
Description:
Examination of Pressure Retaining Welds in Residual Heat Removal and Core Spray Pumps Component Number: All Residual Heat Removal and Core Spray Pressure Retaining Pump Casing Welds Embedded in Concrete Drawing Number: XI-1P-202 and XI-1P-206 (Unit 1)
XI-2P-202 and XI-2P-206 (Unit 2) 2.0 APPLICABLE CODE EDITION AND ADDENDA:
The Inservice Inspection program is based on the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code,Section XI, 2001 Edition through the 2003 Addenda.
3.0 APPLICABLE CODE REQUIREMENT:
The following Code requirements are paraphrased from the 2001 Edition through the 2003 Addenda of ASME Section XI.
Table IWC-2500-1 states that the pump casing welds require a surface examination in accordance with the examination requirements illustrated in Figure IWC-2500-8.
Per Table IWC-2500-1, the multiple-component concept applies, and examinations are limited to either 100% of the welds of one of four Residual Heat Removal pumps and one of four Core Spray pumps (per unit), or distributed among any of the pumps of that same group (per unit) with similar design, size, function, and service in the system. The examination may be performed from either the inside or outside surface of the component.
ISI Program Plan Limerick Generating Station Units 1 & 2, Third Interval 10CFR50.55a RELIEF REQUEST I3R-07 Revision 0 (Page 2 of 3) 4.0 IMPRACTICALITY OF COMPLIANCE:
Pursuant to 10CFR50.55a(g)(5)(iii), relief is requested on the basis that conformance with these code requirements is impractical as conformance would require extensive structural modifications to the Residual Heat Removal and Core Spray pumps.
Limerick Generating Station Units 1 and 2 each have four (4) Class 2 Residual Heat Removal pumps (1(2)A-P202, 1(2)B-P202, 1(2)C-P202 and 1(2)D-P202) and four (4)
Class 2 Core Spray pumps (1(2)A-P206, 1(2)B-P206, 1(2)C-P206, 1(2)D-P206). Per Code Examination Category C-G, surface examination is required on the equivalent of one (1) RHR pump and one (1) Core Spray pump per Unit. However, welds on each of the four (4) Residual Heat Removal and four (4) Core Spray pumps per Unit are encased in concrete and are inaccessible for surface examination.
Therefore, it is impractical to perform the surface weld examination without destruction of the concrete resulting in unnecessary cost and radiation exposure without a compensating increase in safety. Additionally, due to the design of the subject pumps, access to the affected welds can only be achieved through disassembly of the pump, removal of the pump internals, and the required surface examinations performed from the inside surface of the welds. This effort, in the absence of any other necessary pump maintenance, represents a significant expenditure of man-hours and radiation exposure to plant personnel, without a compensating increase in plant safety.
5.0 BURDEN CAUSED BY COMPLIANCE:
Compliance with the applicable Code requirements can only be accomplished by redesigning and refabricating the subject pumps. Based on this, the Code requirements are deemed impractical in accordance with 10CFR50.55a(g)(5)(iii).
6.0 PROPOSED ALTERNATIVE AND BASIS FOR USE:
In the event the subject welds become accessible upon disassembly of any one (1) of the pumps, the welds will be surface examined from the inside surface or a visual (VT-1) examination will be performed for that particular pump group to the maximum extent practicable based on the obstructions and geometric constraints detailed in the Impracticality Of Compliance section of this relief request. The examination method will be determined by Limerick Generating Station based on radiation environment data at the time access is enabled. Additionally, a visual (VT-2) examination during system pressure testing per Examination Category C-H will be performed once each period by examining the surrounding area (exposed areas around the pumps where the pump casing join/merge with the concrete) for evidence of leakage in accordance with IWA-5241(b).
ISI Program Plan Limerick Generating Station Units 1 & 2, Third Interval 10CFR50.55a RELIEF REQUEST I3R-07 Revision 0 (Page 3 of 3)
DURATION OF PROPOSED ALTERNATIVE:
Relief is requested for the Third Ten-Year Inspection Interval for Limerick Generating Station, Units 1 and 2. The third ISI interval began on February 1, 2007 and will conclude January 31, 2017 for Limerick Generating Station, Units 1 and 2.
7.0 PRECEDENTS
Similar relief requests have been approved for:
Limerick Generating Station Second Inspection Interval Relief Request RR-07 was granted per SER dated May 2, 2002. The Third Inspection Interval Relief Request will utilize the same approach that was previously approved in the Second Inspection Interval.
Susquehanna Steam Electric Station Third Inspection Interval Relief Request 3RR-02 was granted per SER dated February 1, 2005.
ISI Program Plan Limerick Generating Station Units 1 & 2, Third Interval 10CFR50.55a RELIEF REQUEST I3R-08 Revision 0 (Page 1 of 4)
Request for Relief for Inservice Inspection Impracticality of Pressure Testing the RPV Head Flange Seal Leak Detection System In Accordance with 10CFR50.55a(g)(5)(iii) 1.0 ASME CODE COMPONENTS AFFECTED:
Code Class: 1
Reference:
Table IWB-2500-1 IWB-5200 Examination Category: B-P Item Number: B15.10
Description:
Pressure Testing the RPV Head Flange Seal Leak Detection System Component Number: Class 1 RPV Head Flange Seal Leak Detection System Drawing Number: ISI-M-41, Sht. 1 (Unit 1)
ISI-M-41, Sht. 4 (Unit 2)
DBA-113-J001, DCA-321-J002, DCA-321-J003, and FJ-DCA-321-J001 (Unit 1)
DBA-213-E001, DCA-421-E001, DCA-421-E002, and DCA-421-J001 (Unit 2) 2.0 APPLICABLE CODE EDITION AND ADDENDA:
The Inservice Inspection program is based on the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code,Section XI, 2001 Edition through the 2003 Addenda.
3.0 APPLICABLE CODE REQUIREMENT:
The following Code requirements are paraphrased from the 2001 Edition through the 2003 Addenda of ASME Section XI.
Table IWB-2500-1, Examination Category B-P, Item Number B15.10, requires all pressure retaining components be subject to a system leakage test (visual (VT-2) examination) in accordance with IWB-5220. This pressure test is to be conducted prior to plant startup following each reactor refueling outage. The pressure retaining boundary for the test conducted at or near the end of each inspection interval shall be extended to all Class 1 pressure retaining components per IWB-5222(b).
ISI Program Plan Limerick Generating Station Units 1 & 2, Third Interval 10CFR50.55a RELIEF REQUEST I3R-08 Revision 0 (Page 2 of 4) 4.0 IMPRACTICALITY OF COMPLIANCE:
Pursuant to 10CFR50.55a(g)(5)(iii), relief is requested on the basis that pressure testing the RPV Flange Leak Detection Line is deemed impractical.
The Reactor Vessel Head Flange Leak Detection Line is separated from the reactor pressure boundary by one passive membrane, a silver-plated O-ring located on the vessel flange. A second O-ring is located on the opposite side of the tap in the vessel flange (See Figure I3R-08.1). This line is required during plant operation and will indicate failure of the inner flange seal O-ring. Failure of the O-ring would result in a High Pressure Alarm in the Main Control Room.
The configuration of this system precludes manual testing while the vessel head is removed. As figure I3R-08.1 portrays, the configuration of the vessel tap, combined with the small size of the tap and the high test pressure requirement (approximately 1045 psig), prevents the tap from being temporarily plugged. Also, when the vessel head is installed, an adequate pressure test cannot be performed due to the fact that the inner O-ring is designed to withstand pressure in one direction only. Due to the groove that the O-ring sits in and the pin/wire clip assembly (See Figure I3R-08.1), pressurization in the opposite direction into the recessed cavity and retainer clips would likely damage the O-ring and thus result in further damage to the O-ring.
5.0 BURDEN CAUSED BY COMPLIANCE:
Pressure testing of this line during the Class 1 System Leakage Test is precluded because the line will only be pressurized in the event of a failure of the inner O-ring. Purposely failing the inner O-ring to perform the Code Required test would require purchasing a new set of O-rings, additional time and radiation exposure to detension the reactor vessel head, install the new O-rings, and then reset and retension the reactor vessel head. This is considered to impose an undue hardship and burden on Limerick Generating Station.
Based on the above, Limerick Generating Station requests relief from the ASME Section XI requirements for system leakage testing of the Reactor Vessel Head Flange Seal Leak Detection System.
6.0 PROPOSED ALTERNATIVE AND BASIS FOR USE:
A visual (VT-2) examination on the Class 1 portion of the RPV Flange Leak Detection Line will be performed during each refueling outage when the RPV head is off and the head cavity is flooded above the vessel flange. The static head developed with the leak detection line filled with water will allow for the detection of any gross indications in the line. This examination will be performed each refuel outage as per the frequency specified by Table IWB-2500-1.
ISI Program Plan Limerick Generating Station Units 1 & 2, Third Interval 10CFR50.55a RELIEF REQUEST I3R-08 Revision 0 (Page 3 of 4) 7.0 DURATION OF PROPOSED ALTERNATIVE:
Relief is requested for the Third Ten-Year Inspection Interval for Limerick Generating Station, Units 1 and 2. The third ISI interval began on February 1, 2007 and will conclude January 31, 2017 for Limerick Generating Station, Units 1 and 2.
8.0 PRECEDENTS
Similar relief requests have been approved for:
LaSalle County Station Second Inspection Interval Relief Request PR-04 was authorized per SER dated July 3, 1996.
Susquehanna Steam Electric Station Third Inspection Interval Relief Request 3RR-07 was authorized per SER dated September 24, 2004.
ISI Program Plan Limerick Generating Station Units 1 & 2, Third Interval 10CFR50.55a RELIEF REQUEST I3R-08 Revision 0 (Page 4 of 4)
FIGURE I3R-08.1 O-RING CONFIGURATION I3R-08-4
ISI Program Plan Limerick Generating Station Units 1 & 2, Third Interval 10CFR50.55a RELIEF REQUEST I3R-09 Revision 0 (Page 1 of 3)
Request for Relief for Alternative Requirements for Pressure Testing the Drywell Pressure Instrumentation In Accordance with 10CFR50.55a(a)(3)(i) 1.0 ASME CODE COMPONENTS AFFECTED:
Code Class: 3
Reference:
IWD-2500, Table IWD-2500-1 Examination Category: D-B Item Number: D2.10
Description:
Alternative Requirements for Pressure Testing the Drywell Pressure Instrumentation Component Number: Drywell Pressure Instrumentation from Penetrations X-22, X-30B, X-40E, and X-50A Drawing Number: ISI-M-42 Sht. 1; ISI-M-57 Sht. 1; ISI-M-59 Sht. 1 (Unit 1)
ISI-M-42 Sht. 3; ISI-M-57 Sht. 4; ISI-M-59 Sht. 3 (Unit 2) 2.0 APPLICABLE CODE EDITION AND ADDENDA:
The Inservice Inspection program is based on the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code,Section XI, 2001 Edition through the 2003 Addenda.
3.0 APPLICABLE CODE REQUIREMENT:
The following Code requirements are paraphrased from the 2001 Edition through the 2003 Addenda of ASME Section XI.
Table IWD-2500-1, Examination Category D-B, Item Number D2.10, requires all pressure retaining components be subject to a system leakage test (visual (VT-2) examination) in accordance with IWD-5220. This pressure test is to be conducted prior to plant startup once each inspection period.
4.0 REASON FOR REQUEST:
Pursuant to 10CFR50.55a(a)(3)(i), relief is requested on the basis that the proposed alternative will provide an acceptable level of quality and safety.
The Limerick drywell pressure is less than 1 psig during normal operation. The pressurizing medium in the drywell and drywell pressure instrumentation is nitrogen gas.
ISI Program Plan Limerick Generating Station Units 1 & 2, Third Interval 10CFR50.55a RELIEF REQUEST I3R-09 Revision 0 (Page 2 of 3)
A visual (VT-2) examination looking for a nitrogen gas leak with less than 1 psig driving pressure would be inconclusive.
Limerick Generating Station Technical Specifications require channel checks every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> to verify drywell pressure instrumentation operability. This is performed by verifying proper pressure readings. A significant tubing leak will cause an improper reading, and will be corrected and retested. The tubing and components are also included in the Integrated Leak Rate Test (ILRT) boundary. Valves HV-42-1(2)47A, B, C, and D are open to perform the ILRT. Therefore, the instrument tubing is subject to the pressure required by the ILRT (44 psig).
In addition, there are no test taps on the subject instrument tubing and plant modifications would be required in order to perform the ASME Section XI pressure tests resulting in a hardship. An additional pressure test once every inspection period to satisfy ASME Section XI requirements is also a hardship in that they would present a redundant testing situation that would result in additional radiation exposure to examination personnel without a compensating increase in the level of quality and safety. The proposed alternative to perform channel checks of the remote pressure indicators to verify drywell pressure instrumentation operability every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> in accordance with the plant Technical Specifications, and the use of 10CFR50 Appendix J, Option B Integrated Leak Rate Testing provides adequate assurance of structural integrity of the tubing and components, and therefore an acceptable level of quality and safety.
5.0 PROPOSED ALTERNATIVE AND BASIS FOR USE:
Drywell pressure instrumentation operability checks will be performed per station Technical Specifications and Integrated Leak Rate Testing will be performed in accordance with the station Appendix J Program, both of which are maintained and controlled independent of the ASME Section XI program.
6.0 DURATION OF PROPOSED ALTERNATIVE:
Relief is requested for the Third Ten-Year Inspection Interval for Limerick Generating Station, Units 1 and 2. The third ISI interval began on February 1, 2007 and will conclude January 31, 2017 for Limerick Generating Station, Units 1 and 2.
7.0 PRECEDENTS
Similar relief requests have been approved for:
Limerick Generating Station Second Inspection Interval Relief Request RR-13-1 was authorized per SER dated May 2, 2002. The Third Inspection Interval Relief Request I3R-09-2
ISI Program Plan Limerick Generating Station Units 1 & 2, Third Interval 10CFR50.55a RELIEF REQUEST I3R-09 Revision 0 (Page 3 of 3) will utilize the same approach that was previously approved in the Second Inspection Interval.
ISI Program Plan Limerick Generating Station Units 1 & 2, Third Interval 10CFR50.55a RELIEF REQUEST I3R-10 Revision 0 (Page 1 of 3)
Request for Relief for Alternative Requirements for Pressure Testing the Suppression Pool Pressure and Level Instrumentation In Accordance with 10CFR50.55a(a)(3)(i) 1.0 ASME CODE COMPONENTS AFFECTED:
Code Class: 3
Reference:
IWD-2500, Table IWD-2500-1 Examination Category: D-B Item Number: D2.10
Description:
Alternative Requirements for Pressure Testing the Suppression Pool Pressure and Level Instrumentation Component Number: Containment Atmospheric Control Tubing to Suppression Pool Pressure and Level Instrumentation Outboard of SV-57-101 (Unit 1) and SV-57-201 (Unit 2)
Drawing Number: ISI-M-57, Sht. 1 and ISI-M-52, Sht. 1 (Unit 1)
ISI-M-57, Sht. 4 and ISI-M-52, Sht. 3 (Unit 2) 2.0 APPLICABLE CODE EDITION AND ADDENDA:
The Inservice Inspection program is based on the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code,Section XI, 2001 Edition through the 2003 Addenda.
3.0 APPLICABLE CODE REQUIREMENT:
The following Code requirements are paraphrased from the 2001 Edition through the 2003 Addenda of ASME Section XI.
Table IWD-2500-1, Examination Category D-B, Item Number D2.10, requires all pressure retaining components be subject to a system leakage test (visual (VT-2) examination) in accordance with IWD-5220. This pressure test is to be conducted prior to plant startup once each inspection period.
4.0 REASON FOR REQUEST:
Pursuant to 10CFR50.55a(a)(3)(i), relief is requested on the basis that the proposed alternative will provide an acceptable level of quality and safety.
The Limerick Generating Station Suppression Pool pressure is less than one (1) psig during normal operation. The pressurizing medium in the Suppression Pool and level I3R-10-1
ISI Program Plan Limerick Generating Station Units 1 & 2, Third Interval 10CFR50.55a RELIEF REQUEST I3R-10 Revision 0 (Page 2 of 3) instrumentation is nitrogen gas. A visual (VT-2) examination looking for a nitrogen gas leak with less than one (1) psig driving pressure would be inconclusive.
Limerick Generating Station Technical Specifications require monitoring suppression pool pressure every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> to verify proper pressure. Additionally, Technical Specifications require channel checks every 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> to verify operability of the suppression pool level indicators. This is performed by verifying proper level readings. A significant tubing leak will give an improper reading, and will be corrected and retested. Also, the tubing and components are also included in the Integrated Leak Rate Test (ILRT) boundary. Valves SV-57-101 and SV-57-201 are open to perform the ILRT. Therefore, the instrument tubing is subject to the pressure required by the ILRT (44 psig).
In addition, there are no test taps on the subject instrument tubing and plant modifications would be required in order to perform the ASME Section XI pressure tests resulting in a hardship. An additional pressure test once every inspection period to satisfy ASME Section XI requirements is also a hardship in that they would present a redundant testing situation that would result in additional radiation exposure to examination personnel without a compensating increase in the level of quality and safety. The proposed alternative to perform channel checks of the remote pressure indicators to verify drywell pressure instrumentation operability every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> in accordance with the plant Technical Specifications, and the use of 10CFR50 Appendix J, Option B Integrated Leak Rate Testing provides adequate assurance of structural integrity of the tubing and components, and therefore an acceptable level of quality and safety.
5.0 PROPOSED ALTERNATIVE AND BASIS FOR USE:
Suppression pool instrumentation operability checks will be performed per station Technical Specifications and Integrated Leak Rate Testing will be performed in accordance with the station Appendix J Program, both of which are maintained and controlled independent of the ASME Section XI program.
6.0 DURATION OF PROPOSED ALTERNATIVE:
Relief is requested for the Third Ten-Year Inspection Interval for Limerick Generating Station, Units 1 and 2. The third ISI interval began on February 1, 2007 and will conclude January 31, 2017 for Limerick Generating Station, Units 1 and 2.
ISI Program Plan Limerick Generating Station Units 1 & 2, Third Interval 10CFR50.55a RELIEF REQUEST I3R-10 Revision 0 (Page 3 of 3)
7.0 PRECEDENTS
Similar relief requests have been approved for:
Limerick Generating Station Second Inspection Interval Relief Request RR-13-4 was authorized per SER dated May 2, 2002. The Third Inspection Interval Relief Request will utilize the same approach that was previously approved in the Second Inspection Interval.
ISI Program Plan Limerick Generating Station Units 1 & 2, Third Interval 10CFR50.55a RELIEF REQUEST I3R-11 Revision 0 (Page 1 of 3)
Request for Relief for Alternative Requirements for Pressure Testing the Hydrogen Recombiner and Combustible Gas Analyzer In Accordance with 10CFR50.55a(a)(3)(i) 1.0 ASME CODE COMPONENTS AFFECTED:
Code Class: 2
Reference:
IWC-2500, Table IWC-2500-1 Examination Category: C-H Item Number: C7.10
Description:
Alternative Requirements for Pressure Testing the Hydrogen Recombiner and Combustible Gas Analyzer Component Number: Post LOCA Recombiner piping and H2/O2 sampling lines (Unit 1 and Unit 2) See Note 1 below for more details.
Drawing Number: ISI-M-57, Shts. 1, 2, and 3; ISI-M-58 Shts. 1 and 2 (Unit 1)
ISI-M-57, Shts. 4, 5, and 6; ISI-M-58 Shts. 3 and 4 (Unit 2)
Note 1: A more detailed description of the pressure testing boundary is identified below.
LGS Unit 1: Class 2 Post LOCA Recombiner piping HBB-128 and HBB-127 between and including "A" Recombiner and valves HV-57-161 and HV-57-162. HBB-126 and HBB-124 between and including "B" Recombiner and valves HV-57-163 and HV 164.
Class 2 hydrogen/oxygen sampling lines HCB-116 and HCB-117, between connections on the Combustible Gas Analyzer Package 10-S205, and valves SV-57-159, SV-57-141, SV-57-142 and SV-57-147B, SV-57-143, SV-57-144 and SV-57-146B, and SV-57-145 (HCB-117). HCB-116 and HCB-117, between connections on the Combustible Gas Analyzer Package 10-S206, and valves SV-57-184 and SV-57-146A, SV-57-186 and SV-57-147A, SV-57-195, SV-57-190 and 57-1090, and SV-57-185 (HCB-117).
LGS Unit 2: Class 2 Post LOCA Recombiner piping HBB-228 and HBB-227 between and including "A" Recombiner and valves HV-57-261 and HV-57-262. HBB-226 and HBB-224 between and including "B" Recombiner and valves HV-57-263 and HV 264.
Class 2 hydrogen/oxygen sampling lines HCB-216 and HCB-217, between connections on the Combustible Gas Analyzer Package 20-S205, and valves SV-57-259, SV-57-241, SV-57-242 and SV-57-247B, SV-57-243, SV-57-244 and SV-57-246B, and SV-57-245 (HCB-217). HCB-216 and HCB-217, between connections on the Combustible Gas I3R-11-1
ISI Program Plan Limerick Generating Station Units 1 & 2, Third Interval 10CFR50.55a RELIEF REQUEST I3R-11 Revision 0 (Page 2 of 3)
Analyzer Package 20-S206, and valves SV-57-284 and SV-57-246A, SV-57-286 and SV-57-247A, SV-57-295, SV-57-290 and 57-2090, and SV-57-285 (HCB-217).
2.0 APPLICABLE CODE EDITION AND ADDENDA:
The Inservice Inspection program is based on the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code,Section XI, 2001 Edition through the 2003 Addenda.
3.0 APPLICABLE CODE REQUIREMENT:
The following Code requirements are paraphrased from the 2001 Edition through the 2003 Addenda of ASME Section XI.
Table IWC-2500-1, Examination Category C-H, Item Number C7.10, requires all pressure retaining components be subject to a system leakage test (visual (VT-2) examination) in accordance with IWC-5220. This pressure test is to be conducted prior to plant startup once each inspection period.
4.0 REASON FOR REQUEST:
Pursuant to 10CFR50.55a(a)(3)(i), relief is requested on the basis that the proposed alternative will provide an acceptable level of quality and safety.
During normal plant operation, this piping is either isolated or less than one (1) psig (normal containment pressure). The pressurizing medium is essentially nitrogen gas. A visual (VT-2) examination looking for a nitrogen gas leak with less than one (1) psig driving pressure would be inconclusive.
System Contaminated Pipe Inspections (CPI) are performed once per Refuel Outage on post-LOCA recombiner piping. During CPI testing associated with the Leak Reduction Program (UFSAR 6.2.8), this piping is pressurized to 44 psig. CPIs for this system are performed similar to 10CFR50 Appendix J Local Leak Rate Testing and, as such, offer the following advantages over system pressure tests:
A. CPIs are performed more frequently than periodic system leakage tests.
B. CPIs have the ability to quantify leakage that is not feasible with a visual (VT-2) examination on this air filled piping.
C. CPIs conservatively include through-valve leakage that would not be identified in a visual (VT-2) examination.
ISI Program Plan Limerick Generating Station Units 1 & 2, Third Interval 10CFR50.55a RELIEF REQUEST I3R-11 Revision 0 (Page 3 of 3)
In addition, for the hydrogen/oxygen sampling lines the combustible gas analyzer continuously samples containment. A tubing leak will cause improper (high) readings that would be corrected and retested.
IWC-5210(b)(2) allows for gas tests which permit location and detection of through-wall leakage. In the event the CPI fails to meet its acceptance criteria, further testing would be performed to determine the location of the leaks and appropriate corrective maintenance.
An appropriate retest would be performed.
5.0 PROPOSED ALTERNATIVE AND BASIS FOR USE:
System Contaminated Pipe Inspections (CPIs) will be utilized to meet the ASME Section XI IWC-5000 pressure testing requirements and will be maintained and controlled independent of the ASME Section XI program.
6.0 DURATION OF PROPOSED ALTERNATIVE:
Relief is requested for the Third Ten-Year Inspection Interval for Limerick Generating Station, Units 1 and 2. The third ISI interval began on February 1, 2007 and will conclude January 31, 2017 for Limerick Generating Station, Units 1 and 2.
7.0 PRECEDENTS
Similar relief requests have been approved for:
Limerick Generating Station Second Inspection Interval Relief Request RR-13-5 was authorized per SER dated May 2, 2002. The Third Inspection Interval Relief Request will utilize the same approach that was previously approved in the Second Inspection Interval.
ISI Program Plan Limerick Generating Station Units 1 & 2, Third Interval 10CFR50.55a RELIEF REQUEST I3R-12 Revision 0 (Page 1 of 5)
Request for Relief for Alternative Requirements for Pressure Testing the CAC Penetration Piping In Accordance with 10CFR50.55a(a)(3)(i) 1.0 ASME CODE COMPONENTS AFFECTED:
Code Class: 2
Reference:
IWC-2500, Table IWC-2500-1 Examination Category: C-H Item Number: C7.10
Description:
Alternative Requirements for Pressure Testing the CAC Penetration Piping Component Number: Multiple lines (See Note 1 below)
Drawing Number: ISI-M-57, Shts. 1 and 2; and ISI-M-55, Sht. 1 (Unit 1)
ISI-M-57, Shts. 4 and 5 (Unit 2)
Note 1: A more detailed description of the pressure testing boundary is identified below.
LGS Unit 1: Class 2 Primary Containment Atmospheric Control piping, as follows:
- Hydrogen/oxygen sample lines HCB-116, between and including containment penetrations X-28A and X-28B and valves SV-57-142, SV-57-143, SV-57-144 and SV-57-195. Reference P&ID ISI-M-57, Sheets 1 and 2.
- Drywell low flow nitrogen makeup line HCB-116, between and including containment penetration X-62 and valves HV-57-116 and SV-57-159. Reference P&ID ISI-M-57, Sheet 1.
- Hydrogen/oxygen sample lines HCB-116, between and including containment penetrations X-221A and valves SV-57-141 and SV-57-184. Reference P&ID ISI-M-57, Sheets 1 and 2.
- Nitrogen purge line HBB-125, between and including valves HV-57-109, HV-57-121 and HV-57-131. Reference P&ID ISI-M-57, Sheet 1.
- Drywell air purge line HBB-124, between and including valves HV-57-123 and HV-57-135. Reference P&ID ISI-M-57, Sheet 1.
- Suppression pool air purge line HBB-126, between and including valves HV-57-124 and HV-57-147. Reference P&ID ISI-M-57, Sheet 1.
ISI Program Plan Limerick Generating Station Units 1 & 2, Third Interval 10CFR50.55a RELIEF REQUEST I3R-12 Revision 0 (Page 2 of 5)
- Drywell purge to standby gas treatment line HBB-127, between and including valves HV-57-114 and HV-57-115, and line HCB-117, between and including connection to line HBB-127 and valve SV-57-145. Reference P&ID ISI-M-57, Sheets 1 and 2.
- Suppression pool low flow nitrogen makeup line HCB-116, between and including containment penetration X-220A, valve SV-57-190 and connection to drywell low flow nitrogen makeup line HCB-116 to valve 57-1068B. Reference P&ID ISI-M-57, Sheets 1 and 2.
- Hydrogen/oxygen sample line HCB-116, between and including containment penetration X-221B and valves SV-57-186 and HV-55-126. Reference P&ID ISI-M-57, Sheet 2, and ISI-M-55, Sheet 1.
- Drywell purge exhaust bypass line HBB-127, between and including valves 57-1807 and HV-57-117. Reference P&ID ISI-M-57, Sheet 2.
- Suppression pool purge exhaust bypass line HBB-128, between and including valves 57-1810 and HV-57-118. Reference P&ID ISI-M-57, Sheet 2.
- Suppression pool purge air exhaust lines HBB-128 and HCB-117, between and including valves HV-57-104, HV-57-112 and SV-57-185. Reference P&ID ISI-M-57, Sheet 2.
LGS Unit 2: Class 2 Primary Containment Atmospheric Control piping, as follows:
- Hydrogen/oxygen sample lines HCB-216, between and including containment penetrations X-28A and X-28B and valves SV-57-242, SV-57-243, SV-57-244 and SV-57-295. Reference P&ID ISI-M-57, Sheets 4 and 5.
- Drywell low flow nitrogen makeup line HCB-216, between and including containment penetration X-62 and valves HV-57-216 and SV-57-259. Reference P&ID ISI-M-57, Sheet 4.
- Hydrogen/oxygen sample lines HCB-216, between and including containment penetrations X-221A and valves SV-57-241 and SV-57-284. Reference P&ID ISI-M-57, Sheets 4 and 5.
- Nitrogen purge line HBB-225, between and including valves HV-57-209, HV-57-221 and HV-57-231. Reference P&ID ISI-M-57, Sheet 4.
- Drywell air purge line HBB-224, between and including valves HV-57-223 and HV-57-235. Reference P&ID ISI-M-57, Sheet 4.
ISI Program Plan Limerick Generating Station Units 1 & 2, Third Interval 10CFR50.55a RELIEF REQUEST I3R-12 Revision 0 (Page 3 of 5)
- Suppression pool air purge line HBB-226, between and including valves HV-57-224 and HV-57-247. Reference P&ID ISI-M-57, Sheet 4.
- Drywell purge to standby gas treatment line HBB-227, between and including valves HV-57-214 and HV-57-215, and line HCB-217, between and including connection to line HBB-227 and valve SV-57-245. Reference P&ID ISI-M-57, Sheets 4 and 5.
- Suppression pool low flow nitrogen makeup line HCB-216, between and including containment penetration X-220A, valve SV-57-290 and connection to drywell low flow nitrogen makeup line HCB-216 to valve 57-2068B. Reference P&ID ISI-M-57, Sheets 4 and 5.
- Hydrogen/oxygen sample line HCB-216, between and including containment penetration X-221B and valves SV-57-286. Reference P&ID ISI-M-57, Sheet 5.
- Drywell purge exhaust bypass line HBB-227, between and including valves 57-2815 and HV-57-217. Reference P&ID ISI-M-57, Sheet 5.
- Suppression pool purge exhaust bypass line HBB-228, between and including valves 57-2818 and HV-57-218. Reference P&ID ISI-M-57, Sheet 5.
- Suppression pool purge air exhaust lines HBB-228 and HCB-217, between and including valves HV-57-204, HV-57-212 and SV-57-285. Reference P&ID ISI-M-57, Sheet 5.
2.0 APPLICABLE CODE EDITION AND ADDENDA:
The Inservice Inspection program is based on the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code,Section XI, 2001 Edition through the 2003 Addenda.
3.0 APPLICABLE CODE REQUIREMENT:
The following Code requirements are paraphrased from the 2001 Edition through the 2003 Addenda of ASME Section XI.
Table IWC-2500-1, Examination Category C-H, Item Number C7.10, requires all pressure retaining components be subject to a system leakage test (visual (VT-2) examination) in accordance with IWC-5220. This pressure test is to be conducted prior to plant startup once each inspection period.
ISI Program Plan Limerick Generating Station Units 1 & 2, Third Interval 10CFR50.55a RELIEF REQUEST I3R-12 Revision 0 (Page 4 of 5) 4.0 REASON FOR REQUEST:
Pursuant to 10CFR50.55a(a)(3)(i), relief is requested on the basis that the proposed alternative will provide an acceptable level of quality and safety.
During normal plant operation, this piping is either isolated or less than one (1) psig (normal containment pressure). The pressurizing medium is essentially nitrogen gas. A visual (VT-2) examination looking for a nitrogen gas leak with less than one (1) psig driving pressure would be inconclusive.
10CFR50 Appendix J, Option B, Local Leak Rate Testing (LLRTs) is currently performed once per Refuel Outage. During LLRTs, the subject piping is pressurized to 44 psig, a substantially higher pressure than that developed during a periodic system functional test.
As such, the LLRT offers the following advantages over system pressure tests:
A. LLRTs are performed more frequently than periodic system leakage tests.
B. LLRTs have the ability to quantify leakage that is not feasible with a visual (VT-2) examination on this essentially gas-filled piping.
C. LLRTs conservatively include through-valve leakage that would not be identified in a visual (VT-2) examination.
IWC-5210(b)(2) allows for gas tests which permit location and detection of through-wall leakage. In the event the LLRT fails to meets its acceptance criteria, further testing would be performed to determine the location of the leaks and appropriate corrective maintenance.
An appropriate retest would be performed.
5.0 PROPOSED ALTERNATIVE AND BASIS FOR USE:
10CFR50 Appendix J, Option B, Local Leak Rate Testing (LLRT) will be utilized to meet the ASME Section XI IWC-5000 pressure testing requirements and will be maintained and controlled independent of the ASME Section XI program.
6.0 DURATION OF PROPOSED ALTERNATIVE:
Relief is requested for the Third Ten-Year Inspection Interval for Limerick Generating Station, Units 1 and 2. The third ISI interval began on February 1, 2007 and will conclude January 31, 2017 for Limerick Generating Station, Units 1 and 2.
ISI Program Plan Limerick Generating Station Units 1 & 2, Third Interval 10CFR50.55a RELIEF REQUEST I3R-12 Revision 0 (Page 5 of 5)
7.0 PRECEDENTS
Similar relief requests have been approved for:
Limerick Generating Station Second Inspection Interval Relief Request RR-13-6 was authorized per SER dated May 2, 2002. The Third Inspection Interval Relief Request will utilize the same approach that was previously approved in the Second Inspection Interval.