ML20217H130
| ML20217H130 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 04/23/1998 |
| From: | Swailes J NEBRASKA PUBLIC POWER DISTRICT |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20217H135 | List: |
| References | |
| NLS980020, NUDOCS 9804290293 | |
| Download: ML20217H130 (15) | |
Text
1 me M E T @ eT a oms Nebraska Public Power District
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NLS980020 April 23,1998 U.S. Nuclear Regulatory Commission i
Attention: Document Control Desk Washington, D.C. 20555-0001 Gentlemen:
Subject:
Inservice Inspection Relief Requests Cooper Nuclear Station, NRC Docket 50-298, DPR-46
References:
- 1. Letter to G. R. Horn (NPPD) from J. W. Clifford (USNRC) dated October 23, 1997, " Evaluation of the Third Ten-year Interval Inspection Program Plan and Associated Requests for Relief for Cooper Nuclear (TAC No. M94000)."
1996, " Cooper Nuclear Station-Inservice Inspection Relief Request RI-13 (TAC No. M94266)."
Nebraska Public Power District (District) submits two revised and one new inservice inspection relief requests. RI-13, on snubber testing, and RI-17, on pipe integral attachments, were revised to respond to Nuclear Regulatory Commission (NRC) comments (Reference 1). RI-25, which addresses integral attachments on the Service Water pumps, is a new request. The technical justifications and supporting information for these requests are provided in the Attachment.
In Reference 2, the NRC approved the original version of relief request RI-13. In Reference 1, however, the NRC expressed concerns about ternoving the snubber testing program from the current Technical Specifications through the conversion to the Improved Technical Specifications. This concern is addressed by Revision 2 of RI-l 3 which incorporates the inspection and testing requirements of the current Technical Specifications. There are no changes to the snubber testing and inspections currently performed and no other changes to relief request RI-13.
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. NLS980020 April 23,1998 Page 2 of 2 In order to effectively plan for the 1998 refueling outage, the District requests NRC approval of -
these requests for relief by June 30,1998. Should you have any questions concerning this matter, please contact me.
Sincerely, b
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es ce Pr ide t of Nuclear Energy
/dnm Attachmen cc: Regional Administrator USNRC - Region IV Senior Project Manager USNRC - NRR Project Directorate IV-1 Senior Resident Inspector USNRC NPG Distribution L..
l Attachment to Cooper Station 3rd Interval NLS980020 Inservice Inspection Program INSERVICE INSPECTION RELIEF REQUESTS RELIEF REQUEST NUMBER: RI-13, REVISION 2 COMPONENT IDENTIFICATION Code Class:
1,2, and 3
References:
IWF-1220 IWF-5000 Examination Category:
F-A
==
Description:==
Snubbers Component Numbers:
Applicable Safety-Related Class 1,2, and 3 Snubbers CODE REOUIREMENT IWF-1220 states that components shall be examined and tested as specified in IWF-5000.
Table IWF-5000 requires that Preservice and Inservice examinations and tests be performed in accordance with ASME/ ANSI OM-1987, Part 4.
BASIS FOR RELIEE Specific reliefis requested on the basis that the proposed alternative would provide an acceptable level ofquality and safety.
Currently, the Cooper Nuclear Station (CNS) Technical Specifications include a comprehensive program for visual examination and functional testing of safety-related hydraulic and mechanical snubbers, including ASME Code Class designated 1,2, and 3 snubbers. This Technical Specification will be removed by the conversion to the Improved Technical Specifications. The requirements have been reproduced in this revision of the relief request.
A significant portion of the safety related snubbers at CNS are also Code Class. The overlap of the visual examination and testing programs per ASME Section XI and this relief request for the Code Class snubbers presents an unnecessary redundancy.
The snubber visual examination program (Current Technical Specification 3.6 H/4.6.H) and the program required by Subsection IWF of ASME Section XI are similar in content. Both programs include parallel criteria for operability, schedule, and sample size.
The CNS snubber testing program and the testing program required by Subsection IWF of.ASME Section XI are also very similar in content. Both programs include parallel requirements for operability testing. Similar requirements for testing frequency, sample size, and additional sampling for failures are also included in both programs.
Attachment to Cooper Station 3rd Interval NLS980020 Inservice Inspection Program INSERVICE INSPECTION RELIEF REQUESTS RELIEF REQUEST NUMBER: RI-13, REVISION 2, CONTINUED BASIS FOR RELIEF (Continued)
Regarding test frequency and sample size, the CNS Snubber Program calls for random testing of 10% of the total snubber population every 18 months during a shutdown. Due to the random sampling,10% of the Code Class snubbers will be tested, as required by Subsection IWF of Section XI. Over a ten outage cycle,100% of the total snubber population is tested.
Regarding sample expansion for failures, the CNS Snubber Program is similar to the requirements of Subsection IWF of Section XI such that for each snubber which does not meet the functional test criteria, an additional 10% of that type of snubber shall be functionally tested.
It is CNS's position that the snubber visual examination and testing program described below (Current Technical Specification 3.6.H/4.6.H) meets the intent of the program required by ASME Section XI, Subsection IWF. No commensurate increase in plant safety with cost benefit will be realized by imposing both inspection programs on the Code Class snubbers at CNS.
Based on the above, CNS requests relief from the ASME Section XI requirements for visual l
examination and functional testing of Code Class snubbers.
PROPOSED ALTERNATIVES:
CNS will perform visual examinations of Code Class snubbers in accordance with the CNS Snubber Program described below in lieu of the requirements ofIWF-5000.
CNS will perform functional testing of Code Class snubbers in accordance with the CNS Snubber Program described below in lieu of the requirements of IWF-5200 and IWF-5300.
The testing results will be tracked and reported per ASME XI requirements.
1 The examination of Code Class snubber integral attaciunents will be performed in accordance
. with IWB/IWC/IWD-2500.
- 1. During all modes of operation except Cold Shutdown and Refuel, all safety-related snubbers shall be operable except as noted in 2 and 3 below.
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Attachment to Cooper Station 3rd Interval NLS980020 Inservice Inspection Program INSERVICE INSPECTION RELIEF REQUESTS RELIEF REQUEST NUMBER: RI-13, REVISION 2, CONTINUED PROPOSED ALTERNATIVES (Continuedh
- 2. With one or more snubbers inoperable, within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> replace or restore the inoperable snubber (s) to OPERABLE status and perform an engineering evaluation per Specification 4.d on the supported component or declare the supported system or subsystem inoperable and follow the appropriate ACTION statement for that system.
- 3. If a snubber is determined to be inoperable while the reactor is in the shutdown or refuel
. mode, the snubber shall be made operable or replaced prior to reactor startup.
The following surveillance requirements apply to all safety related snubbers
- 1. Visual Insoection Intewal All snubbers shall be visually inspected in accordance with the schedule given in Table RI-13.
Snubbers may be categorized in groups, " accessible" or " inaccessible" based on their accessibility for inspection during reactor operation and by type, hydraulic or mechanical.
These groups may be inspected separately orjointly according to the schedule given in Table RI-13.
- 2. VisualInsoection Accentance Criteria Visual inspections shall verify (1) that there are no visible indications of damage or impaired OPERABILITY, (2) attachments to the foundation or supporting structure are secure.
Snubbers which appear inoperable as a result of visual inspections may be determined OPERABLE for the purpose of establishing the next visual inspection interval, providing that (1) the cause of the rejection is clearly established and remedied for that particular snubber and for other snubbers that may be generically susceptible; and (2) the affected snubber is functionally tested in the as found condition and determined OPERABLE per paragraph 5 or 6 as applicable. However, when the fluid port of a hydraulic snubber is found to be uncovered, the snubber shall be determined inoperable and cannot be determined OPERABLE via functional testing for the purpose of establishing the next visual inspection intenal. All snubbers connected to an inoperable common hydraulic fluid reservoir shall be counted as inoperable snubbers.
- 3. At least once per 18 months during shutdown, a representative sample,10% of the total of each type of snubber in use in the plant, shall be functionally tested either in place or in a bench test. For each snubber that does not meet the functional test acceptance criteria of paragraph 5 or 6, an additional 10% of that type of snubber shall be functionally tested.
Attachment to Cooper Station 3rd Interval NLS980020 Inservice Inspection Program INSERVICE INSPECTION RELIEF REQUESTS RELIEF REQUEST NUMBER: RI-13, REVISION 2, CONTINUED PROPOSED ALTERNATIVES (Continued):
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- 4. The representative sample selected for functional testing shallinclude various configuration, operating environments and the range of size and capacity of snubbers.
In addition to the regular sample, snubbers which failed the previous functional test shall a.
be retested during the next test period. If a spare snubber has been installed in place of a j
failed snubber, then both the failed snubber (ifit is repaired and installed in another position) and the spare snubber shall be retested. Test results of these snubbers may not be included for the resampling.
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- b. Permanent or other exemptions from functional testing for individual snubbers, in high f
radiation zones or that are difficult to remove may be granted by the Commission only if a justifiable basis for exemption is presented and/or snubber life destructive testing was performed to qualify snubber operability for all design conditions at either the completion of their fabrication or at a subsequent date.
If any snubber selected for functional testing either fails to lockup or fails to move, i.e.,
c.
frozen in place, the cause will be evaluated and if caused by manufacturer or design deficiency all snubbers of the same design and subject to the same defect shall be tested or inspected to determine if the defect is present. This testing requirement shall be independent of the requirements stated above for snubbers not meeting the functional test acceptance criteria.
- d. For the snubber (s) found inoperable, an engineering evaluation shall be performed to determine the need for further action or testing on affected components.
- 5. Hydraulic Snubbgrs Functional Test Acceotance Criteria The hydraulic snubber functional test shall verify that:
1
- 1. Activation (restraining action)is achieved within the specified range of velocity or acceleration in both tension and compression.
- 2. Snubber bleed, or release rate, where required, is within the specified range in compression or tension.
Attachment to Cooper Station 3rd Interval NLS980020 Inservice Inspection Program INSERVICE INSPECTION RELIEF REQUESTS PJLQEOSED ALTERNATIVES (Continued):
- 6. Mechanical Snubbers Functional Test Acceotance Critena The mechanical snubber functional test shall verify that:
- 1. The force that initiates free movement of the snubber rod in either tension or compression is less than the specified maximum drag force.
- 2. Activation (restraining action) is achieved within the specified range of velocity or acceleration in both tension and compression.
- 3. Snubber release rate, where required, is within the specified range in compression or tension.
- 7. Snubber Service Life Monitoring A record of the service life of each snubber as noted in paragraph 1, the date at which the designated service life commences, and the installation and maintenance records on which the "j
designated service life is based shall be maintained.
8.
Surveillance Reauirement Concurrent with the first in-service visual inspection and at least once per 18 months thereafter, the installation and maintenance records of each snubber noted in paragraph I shall be reviewed to verify that the indicated service life has not been exceeded or will not be exceeded prior to the next scheduled snubber service life review. If the indicated service life will exceeded prior to the next scheduled snubber service life review, the snubber service life shall be reevaluated or the snubber shall be replaced or reconditioned so as to extend its service life beyond the date of the next scheduled service life review. This reevaluation, replacement or reconditioning shall be indicated in the records.
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Attachment to Cooper Station 3rd Interval NLS980020 Inservice Inspection Program l
INSERVICE INSPECTION RELIEF REQUESTS RELIEF REQUEST NUMBER: RI-13, REVISION 2, CONTINUED l
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PROPOSED ALTERNATIVES (Continued):
TABLE RI-13 SNUBBER VISUAL INSPECTION INTERVAL NUMBER OF INOPERABLE SNUBBERS Population Column A Column B Column C or Category Extend Interval Repeat Interval Reduce Interval (Notes 1 and 2)
(Notes 3 and 6)
(Notes 4 and 6)
(Notes 5 and 6) 1 0
0 1
80 0
0 2
100 0
1 4
l 150 0
3 8
l 200 2
5 13 300 5
12 25 Note 1:
The next visual inspection interval for a snubber population or catcgory size shall be determined based upon the previous inspection interval and the number ofinoperable snubbers found during that interval. Snubbers may be categorized, based upon their accessibility during power operation, as accessible or inaccessible, and by type, hydraulic or mechanical. These categories may be examined separately orjointly.
However, the licensee must make and document that decision before any inspection and shall use that decision as the basis upon which to determine the next inspection interval for that category.
Note 2:
Interpolation between population or category sizes and the number ofinoperable snubbers is permissible. Use next lower integer for the value of the limit for Columns A, B, or C if that integer includes a fractional value ofinoperable snubbers as determined byinterpolation.
Note 3:
If the number ofinoperable snubbers is equal to or less than the number in Column A, the next inspection interval may be twice the previous interval but not greater than 48 months.
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Attachment to Cooper Station 3rd Interval NLS980020 -
Inservice Inspection Program INSERVICE INSPECTION RELIEF REQUESTS RELIEF REQUEST NUMBER: RI-13, REVISION 2, CONTINUED PROPOSED ALTERNATIVES (Continued):
Note 4:
If the number ofinoperable snubbers is equal to or less than the number in Column B but greater than the number in Column A, the next inspection interval shall be the same as the previous interval.
Note 5:
If the number ofinoperable snubbers is equal to or greater than the number in Column C, the next inspection interval shall be two-thirds of the previous interval.
However, if the number ofinoperable snubbers is less than the number in Column C but greater than the number in Column B, the next interval shall be reduced proportionally by interpolation, that is, the previous interval shall be reduced by a factor that is one-third of the ratio of the difference between the number ofinoperable snubbers found during the previous interval and the number in Column B to the difference in the numbers in Columns B and C.
Note 6:
Each surveillance requirement shall be performed within the specified time interval with a maxunum allowable extension not to exceed 25% of the surveillance interval.
APPLICABLE TIME PERIOD Reliefis requested for the third ten-year interval of the Inservice Inspection Program for CNS.
RI-13 Revision I was approved by the NRC on February 27,1996 (TAC No. M94266).
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Attachment to Cooper Station 3rd Interval NLS980020 Inservice Inspection Program INSERVICE INSPECTION RELIEF REQUESTS RELIEF REQUEST NUMBER: RI-17, REVISION 1, CONTINUED RELIEF REQUEST NUMBER: RI-17, REVISION 1 COMPONENT IDENTIFICAT10E Code Class:
I and 2
References:
Code Case 509 Tables IWB and IWC-2500-1 Examination Category:
B-K-1 and C-C Item Numbers:
B10.10, B10.20, B10.30, B10.40, C3.10, C3.20, C3.30, C3.40
==
Description:==
Welded Attachments (Shear Lugs)
Component Numbers:
FWB-BKl-8, RR-BKl-4A, RHA-CEl-2, SDS-CEl-21 CODE REOUIREMENT Code Case 509 states that Class 1 integrally welded attachments shall be examined and tested as specified in Table IWB-2500-1.
Table IWB-2500-1, Category B-K requires a surface examination for a 10% sample of welded attachments.
Code Case 509 states that Class 2 integrally welded attachments shall be examined and tested as specified in Table IWC-2500-1.
Table IWC-2500-1, Category C-C requires a surface examination for a 10% sample of welded attachments.
BASIS FOR RELIEF Specific reliefis requested on the basis that the proposed alternative would provide an acceptable level ofquality and safety.
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The welded attachments, FWB-BKl-8, are located on a 12" NPS class 1 Feedwater line in the l
drywell. This line is connected to the reactor vessel at nozzle N4B. The welded attachments are 2"x 2"x 2" shear lugs adjacent to pipe support RFH-73. The shear lugs on this vertical piping run transfer load from the pipe to the support in the downward direction. Each shear lug is attached with a fillet plus groove weld on three sides. There are no welds on the side of the lug adjacent to the clamp.
In order to examine 100% of the surface for 1/2" on either side of the weld, the pipe clamp must be disassembled. A large temporary support will be required to minimize the impact of the load transfer 1
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Attachment to Cooper Station 3rd Interval NLS980020 Inservice Inspection Program INSERVICE INSPECTION RELIEF REQUESTS RELIEF REQUEST NUMBER: RI-17, REVISION 1, CONTINUED to the nozzle. The installation and removal of this temporary support will require several man-hours of work in a radiation field. Approximately 82% of welded attachment on this support can be examined without removal of the clamp.
The welded attachments, RR-BKl-4A, are located on a 24" NPS Class 1 Recirculation Supply line pipe in the drywell. These attachments are 1"x 3"x 1%" shear lugs adjacent to pipe support RR-H1 A.
The shear lugs on this vertical piping run transfer load from the pipe to the support in the downward i
direction. Each shear lug is attached with a fillet plus groove weld on the two sides. There are no welds on the top or bottom of the lug. In order to examine 100% of the surface for 1/2" beyond the end of the weld, the pipe clamp must be disassembled. A large temporary support will be required.
The installation and removal of this temporary support will require several man-hours of work in a radiation field. Approximately 87% of each welded attachment on this support can be examined without removal of the clamp.
The welded attachments, RHA-CEl-2, are located on a 20" NPS Class 2 Residual Heat Removal line above the Toms. These attachments are 2%"x 2%"x 1%" shear lugs adjacent to pipe support RHS-
- 78. The two sets of shear lugs on this vertical piping run transfer load from the pipe to the support in both the upward and downward directions. Each shear lug is attached with a fillet plus groove weld on the two sides. There are no welds on the top or bottom of the lug. In order to examine 1
100% ofthe surface for 1/2" beyond the end of the weld, the pipe clamp must be disassembled. A I
large temporary support will be required. The installation and removal of this temporary support will require several man-days of work due to its location directly above the Torus. Approximately 85%
1 of each welded attachment on this support can be examined without removal of the clamp.
l The welded attachments, SDS-CEl-21, are located on 8" NPS Class 2 Scram Discharge Volume pipe support SDV-HGR-PSAl. These attachments are 1/2"x 1"x 2" shear lugs adjacent to a box restraint.
i The shear lugs on this vertical piping transfer load from the pipe to the support in the downward direction. The shear lugs are attached with 3/16" fillet welds on all four sides. In order to examine 100% of the surface for 1/2" on either side of the weld, a temporary support must be installed and the box restraint must be cut off. After completion of the examination the restraint must be I
reinstalled by welding and the temporary support removed. Approximately 83% of each welded attachment can be surface examined without removing the support.
4 The Code does not usually require a component to be disassembled solely for examination. In the 1995 Edition,1995 Addenda, Figures IWB-2500-15 and IWC-2500-5 for welded attachments were modified to add the following note: " Examination of surface areas may be limited to the portions of these areas that are accessible without removal of support members" Thus this relief request is consistent with the latest Code requirements. Furthermore, disassembly and reassembly of the
4 Attachment to Cooper Station 3rd Interval NLS980020 Inservice Inspection Program INSERVICE INSPECTION RELIEF REQUESTS RELIEF REQUEST NUMBER: RI-17, REVISION 1, CONTINUED support introduces the chance of an error or damage to the support during the reconstruction.
Transferring load from one support to a temporary support or to other supports in the system may have unintended consequences. Examining the accessible portions of the attachment weld without removing the clamp or restraint clamp will cover most of the required surface, will include the highest stressed regions of the welded attachments, and is sufficient to detect service induced flaws in the welded attachments.
PROPOSED ALTERNATE POSITIONS In lieu of performing the Code required examinations, CNS proposes to examine the above listed welded attachments in accordance with applicable Code requirements to the inaximum extent practicable without removal of the clamp or restraint. The NDE data record will describe in detail the extent of the limitation and will be available for review. Ifindications are detected adjacent to the intervening piping clamp or restraint, the clamp or restraint will be removed as necessary for further evaluation of the indication.
Relief is requested in accordance with 10CFR50.55a(a)(3)(ii).
Compliance with Code requirements will result in hardship or unusual difficulty without a compensating increase in the level of quality or safety.
APPLICABLE TIME PERIOD Reliefis requested for the third ten-year interval of the Inservice Inspection Program for CNS.
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Attachment to Cooper Station 3rd Interval NLS980020 Inservice Inspection Program INSERVICE INSPECTION RELIEF REQUESTS RELIEF REQUEST NUMBER: RI-25, REVISION 0 COMPONENT IDENTIFICATION Code Class:
3
References:
IWD-2500, Code Case N-509 Table IWD-2500-1 Examination Category:
D-A j
Item Numbers:
DI.30
==
Description:==
Pumps, Welded Attachments Component Numbers:
Service Water (SW) Pumps A, B, C, and D CODE REOUIREMENT Code Case N-509 requires a visual examination (VT-1) for a 10% sample of the welded attachments of pump component supports.
BASIS FOR RELIEF Specific relief is requested on the basis that the proposed alternative would provide an acceptable level of quality and safety.
There are four vertical service water pumps. Each SW pump has an interior and exterior fillet weld attaching the pump discharge head to the pump column and a fillet weld attaching the pump column to the mounting plate. The ponions of these welded attachments inside the discharge head am panially inaccessible due to the limited access through the service port in the discharge head and the configuration of the pump column.
A complete examination is not possible.
Approximately 60% of the total weld length is accessible for examination.
PROPOSED ALTERNATE EXAMINAILON As an alternate examination, CNS will perform a visual examination (VT-1) of the accessible portions of welded attachments on two SW pumps. This is a 50% samp'e of the welded atachments of the SW pump component supports.
i Reliefis requested in accordance with 10CFR50.55a(g)(6)(i). The ASME Section XI reqairement is impractical due to access restrictions and the proposed alternative provides an adequate level of quality.
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Attachment to Cooper Station 3rd Interval NLS980020 Inservice Inspection Program l
INSERVICE INSPECTION RELIEF REQUESTS RELIEF REQUEST NUMBER: RI-25, REVISION 0, CONTINUED APPLICABIR TIME PERIOD Relief is requested for the third ten-year interval of the Inservice Inspection Program for CNS.
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1 el ATTACHMENT 3 LIST OF NRC COMMITMENTS l
Correspondence No: NLS900020 The following table identifies those actions committed to by the District in this document. Any other actions discussed in the submittal represent intended or i
planned actions by the District. They are described to the NRC for the NRC's information and are not regulatory commitments.
Please notify the Licensing Manager i
at Cooper Nuclear Station of any questions regarding this document or any associated regulatory commitments.
COMMITTED DATE CO&ITMENT OR OUTAGE RI -13: CNS will perform visual examinations of Code Class snubbers in accordance with the CNS Snubber Program 9"
P i
described below in lieu of the requirements of IWF-5000.
Approval RI-13:
CNS will perform functional testing of Code Class snubbers in accordance with the CNS Snubber Program Contingent upon NRC described below in lieu of the requirements of IWP-5200 Approval and IWF-5300.
The testing results will be tracked and j
reported per ASME XI requirements.
RI-13:
The examination of Code Class snubber integral i
attachments will be performed in accordance with C ntingent upon NRC IWB/IWC/IWD-2500.
Approval RI-17:
CNS will examine integrally welded attachments, FWB-BF1-8, RR-BK1-4A, RHA-CEl-2, SDS-CEl-21, in accordance with applicable Code requirements to the maximum extent practicable without removal of the clamp Contingent upon NRC or restraint. If indications are detected adjacent to the Approval intervening piping clamp or restraint, the clamp or restraint will be removed as necessary for further evaluation of the indication.
RI-25:
CNS will perform a visual examination (VT-1) of Contingent upon NRC the accessible portions of integral attachment welds, on one Service Water pump.
- Approval, i
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PROCEDURE NUMBER 0.42 l
REVISION NUMBER S l
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