ML052370437
| ML052370437 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 09/13/2005 |
| From: | Marinos E NRC/NRR/DLPM/LPD2 |
| To: | Rosalyn Jones Duke Energy Corp |
| Olshan L N, NRR/DLPM, 415-1419 | |
| References | |
| RR 03-006, TAC MC6765, TAC MC6810, TAC MC6811 | |
| Download: ML052370437 (12) | |
Text
September 13, 2005 Mr. Ronald A. Jones Vice President, Oconee Site Duke Energy Corporation 7800 Rochester Highway Seneca, SC 29672
SUBJECT:
OCONEE NUCLEAR STATION, UNITS 1, 2, AND 3 - RELIEF REQUEST NO.03-006 FOR SNUBBER VISUAL EXAMINATION AND FUNCTIONAL TESTING RELATED TO THE FOURTH TEN-YEAR INTERVAL INSERVICE INSPECTION PROGRAM (TAC NOS. MC6765, MC6810, AND MC6811)
Dear Mr. Jones:
By letter dated November 5, 2003, you proposed an alternative (Relief Request No.03-006) to the requirements of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code,Section XI, 1998 Edition up to and including the 2000 Addenda, with regard to visual examination and functional testing of snubbers. You requested to use the Updated Final Safety Analysis, Chapter 16, Selected Licensee Commitment 16.9.18, Snubbers, and associated bases for examination and testing of snubbers in lieu of ASME Code,Section XI, requirements in Article IWF-5000. The alternative was requested for the fourth 10-year inservice inspection interval for Oconee, Units 1, 2, and 3.
We have completed our review of Relief Request No.03-006 and have concluded that your proposed alternative provides an acceptable level of quality and safety. Therefore, the proposed alternative is be authorized pursuant to 10 CFR 50.55a(a)(3)(i). Our Safety Evaluation is enclosed.
Sincerely,
/RA/
Evangelos C. Marinos, Section Chief, Section 1 Project Directorate II Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket Nos. 50-269, 50-270 and 50-287
Enclosure:
As stated cc w/encl: See next page
ML052370437 NRR-028 OFFICE PDII-1/PM PDII-1/LA OGC PDII-1/SC NAME LOlshan CHawes JMLongo EMarinos DATE 08/ 29 /05 08/ 29 /05 09/ 07 /05 09/ 13 /05
Enclosure SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELIEF REQUEST NO.03-006 SNUBBER VISUAL EXAMINATION AND FUNCTIONAL TESTING FOURTH TEN-YEAR INSERVICE INSPECTION PROGRAM DUKE ENERGY COMPANY OCONEE NUCLEAR STATION, UNITS 1, 2, AND 3 DOCKET NOS. 50-269, 50-270, AND 50-287
1.0 INTRODUCTION
By letter dated November 5, 2003, Duke Nuclear Company (Duke Power, the licensee) of Oconee Nuclear Station, Units 1, 2, and 3 (Oconee, Units 1, 2, and 3), proposed an alternative (Relief Request No.03-006) to the requirements of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (BPV) Code (Code),Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, 1998 Edition up to and including the 2000 Addenda, Article IWF-5000, with regard to snubber inservice inspection (ISI) activities at Oconee, Units 1, 2, and 3. ASME Code,Section XI, paragraphs IWF-5300(a) and IWF-5300(b), reference the 1988 Addenda to ASME/ANSI OM-1987, Part 4 (OMa-4, 1988), for snubber visual examination and functional testing. In addition, paragraphs IWF-5200(c) and IWF-5300(c) require that integral and non-integral attachments for snubbers, including lugs, bolting, pins, and clamps be examined in accordance with the requirements of the ASME Code,Section XI, Subsection IWF.
In Relief Request No.03-006, the licensee requested that visual examination and functional testing of snubbers be performed using the Updated Final Safety Analysis, Chapter 16, Selected Licensee Commitment (SLC), 16.9.18, Snubbers, and associated bases, in lieu of the ASME Code requirements in Section XI, Article IWF-5000. The alternative was requested for the fourth 10-year ISI interval at Oconee, Units 1, 2, and 3.
The Code of record for Oconee, Units 1, 2, and 3 for inservice examination and testing of snubbers is the 1998 Edition up to and including the 2000 Addenda of the ASME Code,Section XI, Article IWF-5000.
2.0 REGULATORY EVALUATION
ISI of ASME Code Class 1, 2, and 3 components must be performed in accordance with Section XI of the ASME Code and applicable edition and addenda as required by Title 10 of the Code of Federal Regulations (10 CFR) Section 50.55a(g), except where specific written relief has been granted by the U.S. Nuclear Regulatory Commission (NRC or the Commission) pursuant to 10 CFR 50.55a(g)(6)(i). Section 10 CFR 50.55a(a)(3) states that alternatives to the requirements of paragraph (g) may be used, when authorized by the NRCs Director of the Office of Nuclear Reactor Regulation, if the licensee demonstrates that: (i) the proposed alternatives would provide an acceptable level of quality and safety, or (ii) compliance with the specified requirements would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.
Pursuant to 10 CFR 50.55a(g)(4), ASME Code Class 1, 2, and 3 components (including supports) shall meet the requirements, except the design and access provisions and the pre-service examination requirements, set forth in the ASME Code,Section XI, to the extent practical within the limitations of design, geometry, and materials of construction of the components. The regulations require that the inservice examination of components and system pressure tests conducted during the first 10-year interval and subsequent intervals comply with the requirements in the latest edition and addenda of Section XI of the ASME Code incorporated by reference in 10 CFR 50.55a(b) 12 months prior to the start of the 120-month interval, subject to the limitations and modifications listed therein. The applicable edition of Section XI of the ASME Code for the Oconee, Units 1, 2, and 3 fourth 10-year ISI interval is the 1998 Edition up to and including the 2000 Addenda.
The NRCs findings with respect to authorizing alternatives and granting or denying the relief request are given below.
3.0 TECHNICAL EVALUATION
3.1 Licensee Relief Request The licensee requested authorization of an alternative to the requirements in the ASME Code,Section XI, paragraphs IWF-5300(a) and IWF-5300(b), for visual examination and functional testing of ASME Code Class 1, 2 and 3 snubbers, and IWF-5300(c) for integral and non-integral attachments for snubbers, at Oconee, Units 1, 2, and 3.
3.2 Code Requirements ASME Code,Section XI, paragraph IWF-5300(a), requires that snubber inservice examinations be performed in accordance with OMa-4, 1988, using the VT-3 visual examination method described in IWA-2213. Paragraph IWF-5300(b) requires that snubber functional testing be performed in accordance with OMa-4. Paragraph IWF-5300(c) requires that integral and non-integral attachments for snubbers, including lugs, bolting, pins, and clamps, be examined in accordance with Subsection IWF.
3.3 Licensees Proposed Alternative The licensee proposed to use Oconee SLC 16.9.18 and its associated bases, to perform visual examinations and functional testing of ASME Code Class 1, 2, and 3 snubbers in lieu of meeting ASME Code,Section XI, Article IWF-5000, requirements.
3.4 Licensees Basis of Requesting Relief (as stated)
The current visual inspection program defined by the SLC provides an acceptable level of quality and safety equal to or greater than that of the required OM standard. The SLC visual inspection frequency requirements are identical to those of Subsection ISTD of the ASME OM Code 2000 Addenda, as endorsed per 10CFR50.55a.
ASME Section XI, paragraph IWF-5300(a) requires visual inspections be performed using the VT-3 visual examination method described in paragraph IWA-2213. SLC inspections are similar to the VT-3 method, but inspection personnel are not required to be VT-3 certified. SLC inspections are required to be performed by properly qualified personnel. Duke established Employee Training and Qualification Standards (ETQS) to satisfy the training requirements contained in Dukes Quality Assurance Topical Report, as well as other nuclear regulations. The visual inspections are performed using station Maintenance Procedures (MP). The ETQS task number for snubber visual inspection is MM-OT-0918. Individuals performing the visual inspections per the MP must be qualified to task MM-OT-0918 or be under the direction/supervision of a technically qualified individual in accordance with ETQS. This provides satisfactory assurance that quality visual inspections are performed by competent individuals.
ASME Section XI, paragraph IWF-5300(c) requires integral and nonintegral attachments, including lugs, bolting, pins, and clamps, be examined. The SLC acceptance criteria requires an equivalent examination. These visual inspections verify:
(1) that there are no visible indications of damage or impaired operability, (2) attachments to the foundation or supporting structure are secured, and (3) fasteners for the attachment of the snubber to the component and to the snubber anchorage are functional.
The existing functional testing program defined by the SLC is more conservative than the OM standard. Both programs require testing a minimum of 10% of the snubber population every refueling outage. Per the SLC an additional sample of a minimum of 10% must be tested for each snubber that fails to meet the test acceptance criteria until either none fail or all snubbers have been tested. The OM standard requires the test sample to be increased by a factor of 1+C/2, where C is the number of snubbers found unacceptable. The SLC testing program requires testing a greater number of snubbers per unacceptable snubber using a factor of 1+C. Per the OM Code, for each snubber found unacceptable, an additional sample equal to one-half of the initial sample size would be required. Per the SLC, a supplemental sample equal in size to the initial sample would be tested for each failed snubber. Supplemental testing per the SLC results in twice as many snubbers tested as under the OM code. The SLC testing program provides for a level of quality and safety equal to or greater than that of the OM standard.
The proposed testing requirements as described in the SLC are similar to those previously approved for the recent Request for Alternative No.02-006 for Oconee Nuclear Station, Units 1, 2, and 3 per SER letter dated July 14, 2003.
3.5
NRC Staff Evaluation
The licensee requested authorization of an alternative to the requirements of the ASME Code,Section XI, paragraphs IWF-5300(a), (b), and (c). The licensee proposed that the visual examinations and functional testing of ASME Code Class 1, 2 and 3 snubbers be performed in accordance with the requirements of Oconee, Units 1, 2, and 3 SLC 16.9.8 and its associated bases in lieu of meeting the requirements in the ASME Code,Section XI, paragraphs IWF-5300(a), (b), and (c).
ASME Code,Section XI, paragraph IWF-5300(a), requires that snubber inservice examinations be performed in accordance with OMa-4, 1988, using the VT-3 visual examination method described in IWA-2213. Paragraph IWF-5300(b) requires that snubber functional testing be performed in accordance with OMa-4, 1988. Paragraph IWF-5300(c) requires that integral and non-integral attachments for snubbers, including lugs, bolting, pins, and clamps, be examined in accordance with Subsection IWF.
The OMa-4, 1988, specifies the requirements for inservice visual examination (paragraph 2.3),
and functional testing (paragraph 3.2) of Class 1, 2, and 3 snubbers. Similarly, SLC 16.9.18 of Oconee, Units 1, 2, and 3 imposes surveillance requirements for visual inspection and functional testing of all safety-related snubbers. A visual inspection is the observation of the condition of installed snubbers to identify those that are damaged, degraded, or inoperable as caused by physical means, leakage, corrosion, or environmental exposure. To verify that a snubber can operate within specific performance limits, the licensee performs functional testing that typically involves removing the snubber and testing it on a specially designed stand or bench. The performance of visual examinations is a separate process that complements the functional testing program and provides additional confidence in snubber operability.
Generic Letter (GL) 90-09, Alternative Requirements for Snubber Visual Inspection Intervals and Corrective Actions, was issued on December 11, 1990, and has been approved for use by the NRC. The SLC 16.9.18 incorporates GL 90-09. GL 90-09 acknowledges that the visual inspection schedule (as contained in OMa-4, 1988) is excessively restrictive and that licensees with large snubber populations have spent a significant amount of resources and have subjected plant personnel to unnecessary radiological exposure to comply with the visual examination requirements. GL 90-09 states that its alternate schedule for visual inspection provides the same confidence level as that provided by OMa-4, 1988.
ASME Section XI, paragraph IWF-5300(a), requires that inservice examination be performed in accordance with OMa-4, 1988, using the VT-3 visual examination method described in IWA-2213, and paragraph IWF-5300(b) requires that inservice tests be performed also in accordance with OMa-4, 1988.
The SLC 16.9.18 of Oconee, Units 1, 2, and 3 defines examination requirements, initial sample size, failure evaluation, additional sampling, failure evaluation, subsequent examination intervals, and personnel qualifications that are similar to those provided by OMa-4, 1988. The OMa-4, 1988 requirements and SLC 16.9.18 criteria are compared and summarized in the following table:
Criteria ASME/ANSI OM Part 4 -1988 Oconee Units 1, 2, and 3 SLC 16.9.18 Requirements Examination and testing requirements Paragraph 2.3.1.1, Visual Examination, states that snubber visual examinations shall identify impaired functional ability due to physical damage, leakage, corrosion, or degradation from environmental exposure or operating conditions. Paragraph 3.2.1.1, Operability Test, states that snubber operational readiness tests shall verify activation, release rate, and breakaway force or drag force by either an in-place or bench test.
IWA-2213 also provides requirements for VT-3 examinations of snubbers.
SLC 16.9.18 requires that visual inspections shall verify that: (1) there are no visible indications of damage or impaired operability; (2) attachments to the foundation or supporting structure are secure; (3) fasteners for the attachment of the snubber to the component and to the snubber anchorage are functional; and (4) where possible, freedom of movement is checked to ensure the snubber is not frozen up. SLC 16.9.18 requires in-place or bench tests to verify activation, snubber bleed or release rate, as well as maximum drag force for mechanical snubbers.
Snubber sample size Paragraph 3.2.3 states that each defined test plan group shall use either a 10% sampling plan; a 37 testing sample plan; or a 55 testing sample plan during each refueling outage.
SLC 16.9.18 states that at least once per 18 months during shutdown, a representative sample of 10% of the total mechanical snubbers and hydraulic snubbers in use shall be functionally tested either in place or in a bench test.
Additional sampling The snubbers which have been found unacceptable per the testing criteria shall be subject to paragraph 3.2.3.1 (b), which states that the additional sample size must be at least one-half the size of the initial sample size of the defined test plan group of snubbers.
For each snubber that does not meet the functional test acceptance criteria, SLC 16.9.18 requires an additional minimum of 10% of the snubbers be functionally tested until none are found inoperative or all have been functionally tested.
Criteria ASME/ANSI OM Part 4 -1988 Oconee Units 1, 2, and 3 SLC 16.9.18 Requirements Failure evaluation Paragraphs 2.3.4.1 and 3.2.4.1 state that snubbers not meeting examination and operability testing acceptance criteria shall be evaluated to determine the cause of unacceptability and failure, respectively.
SLC 16.9.18 states that the cause of the rejection should be evaluated for snubbers which are found unacceptable during the visual examination. SLC 16.9.18 states that if a snubber fails the functional testing, an engineering and/or operability evaluation will be performed.
Subsequent examination intervals Paragraph 2.3.2 provides guidance for inservice examination intervals based on the number of unacceptable snubbers discovered.
SLC Table 16.9.18-1 provides a snubber visual inspection interval based on the size of the snubber population and the number of unacceptable snubbers discovered. These requirements are similar to NRC GL 90-09.
Personnel qualifications for VT-3 IWA-2310 states that nondestructive examination (NDE) personnel shall be qualified in accordance with ANSI/ASNT CP-189. IWA-2317 provides alternative qualifications for VT-3 examination personnel.
Duke Power letter dated November 5, 2003, states that Duke established an in-house training and qualification program for personnel performing snubber visual examinations.
Examination and Testing Requirements Oconee SLC 16.9.18 states that visual inspections shall verify that: (1) there are no visible indications of damage or impaired operability; (2) attachments to the supporting structure are secure; (3) fasteners for the attachment of the snubber to the component and to the snubber anchorage are functional; and (4) where possible, freedom of movement is checked to ensure the snubber is not frozen up. SLC 16.9.18 requires in-place or bench tests to verify activation, snubber bleed or release rate, as well as maximum drag force for mechanical snubbers. These requirements are similar to snubber visual examination and operability test requirements of OMa-4, 1988, paragraphs 2.3.1 and 3.2.1. Additionally, in the licensees letter dated November 5, 2003, the licensee states that the SLC inspections are similar to the VT-3 method, which would include verification of clearances, settings, physical displacement, loose or missing parts, debris, corrosion, wear, erosion, and loss of integrity at bolted or welded connections.
The licensees snubber examinations provided in SLC 16.9.18 are, therefore, similar to the VT-3 examination requirements of ASME Code, IWA-2213.
Snubber Sample Size Oconee SLC 16.9.18 requires that a representative sample of 10 percent of the total of mechanical and hydraulic snubbers be functionally tested, either in place or in a bench test, at least once per 18 months, during shutdown. These tests are normally performed during refueling outages. OMa-4, 1988, requires either a 10 percent testing sample plan, 37 testing sample plan, or 55 testing sample plan. The Oconee SLC sample size would, therefore, be comparable to the 10 percent sample testing requirements of the OMa-4, 1988. As a result, the number of snubbers tested during the 18-month period is essentially equivalent to the OMa-4, 1988, requirements.
Additional Sampling OMa-4, 1988, paragraph 3.2.3.1(b), states that for any snubber(s) determined to be unacceptable as a result of testing, an additional sample of at least one-half the size of the initial sample lot shall be tested. That is, for a 10 percent testing sample plan, an additional 5 percent of snubbers in the overall population would need to be tested. If additional snubbers are required to be tested due to the failure of a snubber to meet acceptance criteria, the Oconee SLC requires that an additional 10 percent of snubbers be tested. The SLC requirements are more conservative than the OMa-4, 1988, requirements. Therefore, the NRC staff finds the SLC additional sampling requirements to be acceptable Failure evaluation OMa-4, 1988, requires that snubbers not meeting examination and/or operability testing criteria shall be evaluated to determine the cause (paragraphs 2.3.4.1 and 3.2.4.1). The root cause evaluation shall review information related to other unacceptable snubbers and determine whether other snubbers of similar design would require further examination. SLC 16.9.18 states that the cause of the rejection should be evaluated for snubbers which are found unacceptable during the visual examination. It further states that if a snubber fails the functional testing, an engineering and/or operability evaluation will be performed. In addition, SLC 16.9.18 states that for any snubber that fails to lockup or fails to move, i.e., is seized, and engineering evaluation will be performed to determine if the mode of failure could affect other snubbers of the same design. Therefore, the NRC staff considers Oconees SLC 16.9.18 requirements to be equivalent to the OMa-4, 1988, requirements.
Subsequent Examination Intervals OMa-4, 1988, paragraph 2.3.2, provides guidance for examination intervals. This paragraph provides a table based on the number of unacceptable snubbers. SLC Table 16.9.18-1 provides a snubber visual inspection interval based on the size of snubber population and the number of unacceptable snubbers discovered. SLC Table 16.9.18-1 is similar to the guidance contained in NRC GL 90-09, Alternative Requirements for Snubber Visual Inspection Intervals and Corrective Actions, dated December 11, 1990, which has been approved for use by the NRC. Therefore, the NRC staff considers the snubber visual examination intervals contained in Oconee SLC 16.9.18 to be acceptable.
Personnel Qualifications The applicants letter dated November 5, 2003, stated that SLC inspections are similar to the VT-3 method, but the inspection personnel are not required to be VT-3 qualified. The applicant stated that SLC inspections are required to be performed by properly qualified personnel. The applicant established Employee Training and Qualification Standards (ETQS) to satisfy the training requirements contained in Dukes Quality Assurance Topical Report as well as other nuclear regulations. The visual inspections are performed using station Maintenance Procedures (MP). The ETQS task number for snubber visual inspection is MM-OT-0918.
Individuals performing the visual inspections per the MP must be qualified to task MM-OT-0918 or under the direction/supervision of a technically qualified individual in accordance with ETQS.
The qualification and certification program for personnel conducting snubber examinations at Oconee, Units 1, 2, and 3 are equivalent to the ASME Code qualification requirements for VT-3 NDE personnel. Therefore, the NRC staff finds the licensees qualification program acceptable.
Integral and Non-integral Attachments ASME Section XI, IWF-5300(c), requires that integral and non-integral attachments be examined. SLC 16.9.18 makes no distinction between integral and non-integral attachments.
Both integral and non-integral attachments are included in the examination to verify overall structural integrity. The licensee stated that visual inspections performed in accordance with SLC 16.9.18 verify that: (1) there are no visible indications of damage or impaired operability, (2) attachments to the foundation or supporting structure are secure, and (3) fasteners for the attachment of the snubber to the component and to the snubber anchorage are functional. The staff considers that the above SLC 16.9.18 visual inspections provide an equivalent examination for the integral and non-integral attachments as required by IWF-5300(c), and are, therefore, acceptable.
Based on the above discussions, the NRC staff finds that snubber visual examinations and functional testing, conducted in accordance with SLC 16.9.18, provide reasonable assurance of snubber operability equivalent to that of the ASME Code,Section XI. Therefore, the NRC staff finds the licensees proposed alternative provides an acceptable level of quality and safety with respect to snubber visual inspection and functional testing. It should be noted that in authorizing Relief Request No.03-006, SLC 16.9.18 becomes a regulatory requirement that may be used in lieu of ASME Code,Section XI, requirements for performing ISI and functional testing of snubbers. Any future changes to these requirements shall be reviewed and approved by the NRC staff for authorization pursuant to 10 CFR 50.55a(a)(3) or as an exemption pursuant to 10 CFR 50.12.
4.0 CONCLUSION
Based on the information provided, the NRC staff concludes that the proposed alternative to use Selected Licensee Commitment 16.9.18 for snubber visual inspection and functional testing provides an acceptable level of quality and safety. Therefore, pursuant to 10 CFR 50.55a(a)(3)(i), the licensees alternative is authorized for the Oconee, Units 1, 2, and 3 fourth ten-year ISI interval.
5.0 REFERENCES
U.S. Code of Federal Regulations, Domestic Licensing of Production and Utilization Facilities, Part 50, Chapter I, Title 10, Energy, Section 50.55a, Codes and standards.
Generic Letter (GL) 90-09, Alternative Requirements for Snubber Visual Inspection Intervals and Corrective Actions, dated December 11, 1990.
American Society of Mechanical Engineers Boiler and Pressure Vessel Code,Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components.
American Society of Mechanical Engineers Operation and Maintenance Code, Inservice Testing of Nuclear Power Plant Components.
Letter from R. A. Jones, Duke Energy Company, to NRC, Duke Energy Company Oconee Nuclear Station Unit 1 Docket No. 50-269, Fourth Ten-Year Inservice Inspection Interval Plan, dated November 5, 2003.
Principal Contributor: A. Lee Date: September 13, 2005
Oconee Nuclear Station, Units 1, 2, and 3 cc:
Ms. Lisa F. Vaughn Duke Energy Corporation Mail Code - PB05E 422 S. Church St.
Charlotte, NC 28201-1006 Manager, LIS NUS Corporation 2650 McCormick Dr., 3rd Floor Clearwater, FL 34619-1035 Senior Resident Inspector U.S. Nuclear Regulatory Commission 7812B Rochester Highway Seneca, SC 29672 Mr. Henry Porter, Director Division of Radioactive Waste Management Bureau of Land and Waste Management Dept. of Health and Env. Control 2600 Bull St.
Columbia, SC 29201-1708 Mr. Michael A. Schoppman Framatome ANP 1911 North Ft. Myer Dr.
Suite 705 Rosslyn, VA 22209 Mr. B. G. Davenport Regulatory Compliance Manager Oconee Nuclear Site Duke Energy Corporation ON03RC 7800 Rochester Highway Seneca, SC 29672 Mr. R. L. Gill, Jr.
Manager - Nuclear Regulatory Issues and Industry Affairs Duke Energy Corporation 526 S. Church St.
Mail Stop EC05P Charlotte, NC 28202 Division of Radiation Protection NC Dept of Environment, Health, & Natural Resources 3825 Barrett Dr.
Raleigh, NC 27609-7721 Mr. Peter R. Harden, IV VP-Customer Relations and Sales Westinghouse Electric Company 6000 Fairview Road 12th Floor Charlotte, NC 28210 Mr. Henry Barron Group Vice President, Nuclear Generation and Chief Nuclear Officer P.O. Box 1006-EC07H Charlotte, NC 28201-1006 Ms. Karen E. Long Assistant Attorney General NC Department of Justice P.O. Box 629 Raleigh, NC 27602