ML16342D567
| ML16342D567 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 03/12/1997 |
| From: | Steven Bloom NRC (Affiliation Not Assigned) |
| To: | Rueger G PACIFIC GAS & ELECTRIC CO. |
| References | |
| TAC-M95068, TAC-M95069, NUDOCS 9703130395 | |
| Download: ML16342D567 (20) | |
Text
March i2, 1997 Hr. Gregory H. Rueger Pacific Gas and Electric Company NPG Mail Code A10D P. 0.
Box 770000 San Francisco, California 94177
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION (RAI) REGARDING THE DIABLO CANYON POWER PLANT, UNITS 1
AND 2, SECOND 10-YEAR INTERVAL INSERVICE INSPECTION PROGRAM PLAN AND ASSOCIATED REQUESTS FOR RELIEF (TAC NOS.
H95068 AND H95069)
Dear Hr. Rueger:
By letter dated November 19, 1996, Pacific Gas and Electric Company (PG&E),
submitted the second ten-year interval inservice inspection (ISI) program plan and associated requests for relief for Diablo Canyon Power Plant, Units 1 and (DCPP).
The NRC, with assistance from its contractor, Idaho National Engineering Laboratory (INEL), is reviewing and evaluating the second ten-year interval inservice inspection program plan and associated requests for relief from the ASME Boiler & Pressure Vessel
- Code,Section XI requirements.
Additional information, as discussed in the enclosure, is required in order for the staff to complete its review.
PG&E, to expedite the review process, is requested to send a copy of the RAI response to NRC's contractor, INEL, at the following address:
Michael T. Anderson INEL Research Center 2151 North Boulevard P.O.
Box 1625-Idaho Falls, Idaho 83415-2209 We request that you respond to this RAI within 60 days from receipt of this letter.
Sincerely, Original Signed By Steven D. Bloom, Project Manager Project Directorate IV-2 Division of Reactor Projects III/IV Office of Nuclear Reactor Regulation Docket Nos.
50-275 and 50-323
Enclosure:
Request for Additional, Informati on cc w/encl:
See next page 3 3 0 0 8 3.
DOCUMENT NAME:
DC95068.RAI DISTRIBUTION:
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Hr. Gregory H. Rueger Narch 12, 1997 cc w/encl:
NRC Resident Inspector Diablo Canyon Nuclear Power Plant c/o U.S. Nuclear Regulatory Commission P. 0.
Box 369 Avila Beach, California 93424
'I Dr. Richard Ferguson, Energy Chair Sierra Club California 1100 11th Street, Suite 311 Sacramento, California 95814 Hs.
Nancy Culver San Luis Obispo Mothers for Peace P. 0.
Box 164 Pismo Beach, California 93448 Chairman San Luis Obispo County Board of Supervisors Room 370 County Government Center San Luis Obispo, California 93408 Hr. Truman Burns Nr. Robert Kinosian California Public Utilities Commission 505 Van Ness, Room 4102 San Francisco, California 94102 Nr. Steve Hsu Radiologic Health Branch State Department of Health Services Post Office Box 942732 Sacramento, California 94232 Diablo Canyon Independent Safety Committee ATTN:
Robert R. Mellington, Esq.
Legal Counsel 857 Cass Street, Suite D
Monterey, California 93940 Regional Administrator, Region IV U.S. Nuclear Regulatory Commission Harris Tower 5 Pavillion 611 Ryan Plaza Drive, Suite 400 Arlington, Texas 76011-8064 Christopher J. Marner, Esq.
Pacific Gas 5 Electric Company Post Office Box 7442 San Francisco, California 94120 Hr. Robert P.
Powers Vice President and Plant Manager Diablo Canyon Nuclear Power Plant P. 0.
Box 56 Avila Beach, California 93424 Telegram-Tribune ATTN:
Hanaging Editor 1321 Johnson Avenue P.O.
Box 112 San Luis Obispo, California 93406
IABLO CANYON POWER PLANT UNITS 1
& 2 PACIFIC GAS AND ELECTRIC COMPANY DOCKET NOS.
50-275 ND 50-323 E VEST FOR ADDI IONAL FORMATION SECO D 10-YEAR INT RV INSERVIC NSPECTION ROGRAM P AN Sco e Status of Review Throughout the service life of a water-cool'ed nuclear power facility, 10 CFR 50.55a(g)(4) requires that components (including supports) that are classified as American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code Class 1, Class 2,
and Class 3 meet the requirements, except design and access provisions and preservice examination requirements, set forth in ASME Code Section XI, Rules for Inservice Inspeckion of Nuclear Power Plank Components, to the extent practical within the limitations of design,
- geometry, and materials of construction of the components.
This section of the regulations also requires that inservice examinations of components and system pressure tests conducted during successive 120-month inspection intervals comply with the requirements in the latest edition and addenda of the Code incorporated by reference in the Code of Federal Regulations (CFR) 10 CFR 50.55a(b) on the date 12 months prior to the start of the 120-month interval, subject to the limitations and modifications listed therein.
The components (including supports) may meet requirements set forth in subsequent editions and addenda of the Code that are incorporated by reference in 10 CFR 50.55a(b) subject to the limitations and modifications listed therein.
The licensee, Pacific Gas and Electric Company, has prepared the Diablo Canyon Power Plank, Units I and 2, Second 10-Year Inkerval Inservice Inspeckion Program Plan, Revision 0, to meet the requirements of the 1989 Edition of Section XI of the ASME Code.
The staff has reviewed the Pacific Gas and Electric Company, Diablo Canyon Power Plank, Units 1 and 2, Second 10-Year Interval Inservice Inspection Program Plan, Revision 0, submitted by letter dated November 19,
- 1996, and the requests from the ASME Code requirements.
The second 10-year interval start dates are January 1,
1996, for Unit 1
and June 1, 1996, for Unit 2.
The Code of record for the second 10-year interval is the 1989 Edition of the ASME Section XI.
dd'tio al n o atio e uired Based on the above review, the staff has concluded that additional information and/or clarification is required to complete the review of the ISI Program Plan.
k N
A.
Address the degree of compliance with augmented examinations that have been established by the NRC when added, assurance of structural reliability is deemed necessary.
Examples of documents that address augmented examinations.are:
(1)
Branch Technical Position HEB 3-1, High Energy Fluid
'ystems, Protection Against Postulated Piping Failures in Fluid Systems Outside Containment; (2)
Regulatory Guide 1.150, Ultrasonic Testing of Reactor Vessel fields During Preservice and Inservice Examinations.
Discuss these and any other augmented examinations that may have been incorporated in the Diablo Canyon Power Plant, Units I and 2, Second 10-Year Interval Inservice Inspection Program Plan, Revision 0.
B.
Discuss any plans or schedules for examination of a sample of the welds in the Residual Heat Removal (RHR),
Emergency Core Cooling (ECC),
and Containment Heat Removal (CHR) systems to assure the continued integrity of thin-wall piping excluded from selection by the Code.
Paragraph 10 CFR 50.55a(b)(2)(iv) requires that certain ASNE Code Class 2 piping welds in these systems be examined.
These systems are critical to the safe shutdown of the plant and should not be completely excluded from inservice volumetric examination based on piping wall thickness. 'he staff has previously determined for similar plants that a 7.5X augmented volumetric sample of thin-wall welds constitutes an acceptable resolution.
C.
Provide the staff with the status of the augmented reactor pressure vessel examinations required by the 10 CFR 50.55a(g)(6)(ii)(A), effective September 8,
- 1992, (Note:
plants with greater than 40 months remaining in the interval on the effective date of the rule, were required to perform the augmented examination in that interval) and provide a technical discussion describing how the regulation was/will be implemented at Diablo Canyon Power Plant, Units 1 and 2.
Include in the discussion a description of the approach and any specialized techniques or equipment that was/will be used to complete the required augmented examination.
D.
The licensee must state the specific paragraph of the regulations under which each proposed alternative or request for relief is submitted.
The licensee should review the current submittals and provide the required references to ensure that each proposed alternative or request for relief is evaluated in accordance with
.the appropriate criteria, as discussed below.
A licensee may propose an alternative to CFR or Code requirements in accordance with 10 CFR 50.55a(a)(3)(i) or 10 CFR 50.55a(a)(3)(ii).
When submitting a proposed, alternative, the licensee must specify the appropriate regulatory basis.
Under 10 CFR 50.55a(a)(3)(i),
the proposed alternative must be shown to provide an acceptable level of quality and safety, i.e.,
essentially be equivalent to the original requirement in terms of quality arid safety.
Under 10 CFR 50.55a(a)(3)(ii),
the licensee must show that compliance with the original requirement results in a hardship or unusual difficultywithout a compensating increase in the level of quality and safety.
Examples of hardship and/or unusual difficulty include, but are not limited to, excessive radiation exposure, disassembly of components solely to provide access for examinations, and development of sophisticated tooling that would result in only minimal increases in examination coverage.
In accordance with 10 CFR 50.55a(g)(5)(iii),
a licensee may submit a request for relief from ASME Code requirements.
If a licensee determines that conformance with certain ASME Code requirements is impractical for its facility, the licensee shall notify the Commission and submit, as specified in 550.4, information to support that determination.
When a licensee determines that an inservice inspection requirement is impractical, e.g.,
the system would have to be redesigned or a component would have to be replaced to enable inspection, the licensee should cite this part of CFR to support the criteria for evaluation.
The NRC may, giving due consideration to the burden placed on the licensee, impose an alternative examination requirement.
In accordance with 10 CFR 50.55a(c)(3),
and 10 CFR 50.55a(e)(2),
ASME Code cases may be used as alternatives to Code requirements.
Code cases that the NRC has approved for use are published in Regulatory Guide 1. 147, Inservice Inspection Code Case Acceptability, with any additional conditions the NRC may have imposed.
When used, these Code cases must be implemented in their entirety.
ASME approved Code cases awaiting NRC acceptance and subsequent publication in Regulatory Guide 1. 147 may be adopted only if the 'licensee
- requests, and the NRC authorizes, their use on a case-by-case basis.
For Code Cases not published in Regulatory Guide 1.147, their use may be acceptable when conditions deemed appropriate by the NRC are included.
As such, a licensee proposing the use of alternative(s) of currently unpublished Code Case(s),
must commit to certain conditions, as applicable.,
Provide a list of all Code Cases that the licensee intends to implement during the second 10-year interval.
For the following unpublished Code cases in Regulatory Guide 1. 147, the NRC has determined that these Code cases are acceptable with the following conditions:
F.
For Code Case N-509, Alternative Rules for the Selection and Examination of Class I, 2, and 3 Integrally k(elded Attachments, the NRC staff finds this alternative to Code requirements acceptable only if the licensee commits to the examination of 10 percent of all integral attachments in nonexempt portions of Code Class 1, 2, and 3 systems.
For Code Case N-416-1, Alternative Pressure Test Requirement for fielded Repairs or Installation of Replacement. Items by klelding, Class I, 2, and 3, the NRC staff finds this alternative to Code requirements acceptable only if the licensee commits to performing a surface examination of the root pass weld layer for welded repairs and replacements in Class 3 systems.
For Code Case N-522, Pressure'esting of Containment Penetration Piping, the NRC staff finds this alternative to Code requirements
'acceptable only if the licensee commits to performing the pressure test at peak design pressure and implement a procedure for the detection and location of through wall flaws.
For Code Case N-546, Alternative Requirements for Qualification of VT-2 Visual Examination Personnel, the NRC staff finds this alternative to Code requirements acceptable only if the licensee commits to (1) developing procedural guidelines for obtaining consistent, quality VT-2 visual examinations; (2) document and maintain records to verify the qualification of persons selected to perform VT-2 visual examinations; and (3) implement independent review and evaluation of leakage by persons other than those that performed the VT-2 visual examinations.
When requesting to implement Code cases that have not been published in Regulatory Guide 1.147, the licensee should either confirm that the conditions will be adopted or provide the action the licensee proposes to take with regard to these conditions.
In the licensee's submittal, Piping and Instrumentation
- Diagrams, coded to show Class 1, 2, and 3 class boundaries are provided.
However, these drawings are not legible.
To support the program review, provide a set of drawings that are legible.
G.
Under i ati o to, the licensee states:
"Class 2 pipe weld examinations in Unit 2 followed a single stream schedule based on the Code addenda current during the preservice examinations, as permitted by an approved request for relief in the first inspection interval; that schedule is continued here."
t I
Based on this statement, it is unclear if the licensee is complying with the percent of examination area selection requirements of the Code.
Therefore, verify that a 7-1/2X sample of all nonexempt Code Class 2 welds, distributed among all the systems and line sizes, are scheduled for examination in the second interval for Units 1 and 2.
The licensee has not provided a summary of examinations scheduled for the second interval.
Therefore, provide a summary of scheduled examinations by examination category.
The summary will be used to verify that the percentage of examinations for each period, required under Tables IWB-2412-1 and IWC-2412-1, Inspection Program B, will be satisfied for Units 1 and 2.
The licensee has submitted several requests for relief based on estimated examination coverages.
The licensee has also noted that differences in estimated coverages may occur due to use of automated
- scanners, which provide a higher quality examination, but may experience more limited coverage.'he Code requires that all examinations be performed to the extent practical.
This may require a combination of manual and automated examinations.
Therefore, if coverages obtained for subsequent examinations do not meet or exceed previous examinations, the licensee must provide a basis for the reduced coverage.
It should be noted that for the requests currently being evaluated, if the actual coverages do not meet or exceed the estimated coverages, the licensee will. be required to resubmit for relief.
As such, the licensee may want to consider submittal 'of reliefs following the actual examinations.
Describe the action the licensee proposes to take regarding examination coverages.
For Request for Relief NDE-6, Revision 1, it appears that the licensee is submitting for relief from Code-required examination volumetric coverage as well'as scheduling requirements for the reactor.pressure vessel nozzle examinations.
Because there are two separate subjects associated with this submittal, 'of which the scheduling requirements may relate to other requests, it is requested that this relief be submitted as two separate requests.
For some of the requests (for example NDE-7), it appears that the costs of examinations is the basis for requesting relief. It should be noted that requests for relief that use costs ~ol as the basis for relief are unacceptable.
- Further, when requesting deferral of examinations, relief can only be authorized when no more than 10-years elapse between examinations.
Maintaining essentially 10-years between examinations is typically obtained by
reexamination of areas being rescheduled at or near the end of an interval to establish a new schedule of successive.
examinations.
Review all requests that include deferral-of examinations and verify that no more than essentially 10-years will elapse between examinations.
4 In Request for Relief NDE-8, the licensee requests relief from nozzle inner radius examinations.
Although relief from inner radius examinations may have been given in the past, new NDE technology is being implemented to satisfy volumetric examination requirements of inner radius sections.
Provide a discussion of the technologies that have to be investigated and/or further basis'or not performing the Code-required inner radius section examinations.
The licensee noted that the calibration blocks and standards for the volumetric examinations are controlled by a separate approved PGE Procedure.
Provide a list of calibration blocks that will be used during the second interval.
Verify that all of the calibration blocks being used as standards for ultrasonic examination meet the minimum design and material requirements of the 1989 Edition of the Code.
For Request for Relief NDE-26 (Unit 2), the licensee requested relief from surface examination of the pressurizer support skirt weld as defined by Fig'ure IWB-2500-13, area C-D.
The licensee proposes to perform a surface examination of area A-B only.
(Other licensees are performing a volumetric examination from the outside surface of area C-D.)
Is the pressurizer skirt weld, area C-D amenable to a volumetric examination?
Has the licensee investigated the possibility of an alternative volumetric examination?
For Request for Relief NDE-9, the licensee has requested relief from steam generator primary side nozzle inner radius examinations.
No alternative has been proposed.
Can a visual examination of the inner radius area be performed when the steam generators are open for eddy current examination of the tubes?
New NDE technology is being implemented to satisfy volumetric examination requirements for nozzle inner radius section examinations.
Provide a discussion of the technologies that have been investigated and/or further basis for not performing the Code-required inner. radius examinations.
For Request for Relief NDE-17, the licensee is requesting relief from Code examinations of steam generator shell welds.
The licensee states that 20 percent of each of the subject welds is being examined.
Is this 20 percent of each weld on each steam
t
generator?
If so, it appears that only minor modifications would be required to examine the equivalent of one of each structural discontinuity weld.
Provide a discussion why the minimum Code requirement cannot be satisfied.
In addition, it appears that for some vessels included in Request for Relief NDE-17, the licensee should consider applying exemption criteria allowed by Code Case N-408-2.
Criteria for exempting components within piping, exempt based on line size, is allowed.
Provide a discussion on the classification of the filters and heat exchangers and provide the line sizes that connect to these vessels.
If some of these components can be exempted, other requests associated with these components should also be reviewed.
g.
For Request for Relief PRS-4, it is unclear why the Fuel'ransfer Tube to Refueling Canal is Class 1.
Is this component classified correctly or is it part of NC that is tested under Appendix J?
Please clarify the requirement for this request.
R.
For several
- requests, the licensee has proposed alternatives to Code requirements that appear to be addressed in ASNE approved Code cases.
Where the ASNE Code Committee has identified Code requirements that may result in a burden on the licensee without providing;a compensating increase in quality and safety, or alternatives have been developed that provide equivalency to Code requirements, Code cases have been written.
As such, the NRC believes that existing Code cases that have been approved for use by the ASNE Code Committee, but have not been published in Regulatory Guide 1. 147, should be given first consideration as alternatives to Code requirements.
Therefore, it is recommended that the licensee review current ASNE Code cases for applicability.
Examples of Code cases that appear to be applicable to certain requests include:
Request for Relief NDE-6, Revision 1, proposes an alternative to reactor pressure vessel nozzle examination'scheduling.
Code Case N-521, Alternative Rules for Deferral of Inspections of Nozzle-Co-Vessel fields, Inside Radius Section, and Nozzle-Co-Safe End fields of a Pressurized Mater Reactor Vessel, has been found acceptable for use.
Note: Conditions established for use of this Code Case require that essentially no more than 10-years elapse between examinations.
Request for Relief PRS-l, proposes alternatives to insulation removal for VT-2 visual examination of bolting in Class 1 and 2, borated systems.
Describe the action the licensee proposes to take regarding the apparent conflict between the Code requirement for insulation removal from bolted connections in systems borated for the purpose of controlling reactivity.'he Code does not have an exception to the insulation removal requirement based on bolting material.
Some austenitic bolting materials have been
I W
found to be susceptible to primary water stress corrosion.
As a
- result, the NRC has found it unacceptable to exclude austenitic bolted connections from insulation removal.
Code Case N-533, Alternative Requirements for VT-2 Visual Examination of Class 1
Insulated Pressure-Retaining Bolted Connections has been found acceptable for use.
Request for Relief PRS-2, proposes an alternative to testing Class 2 containment pipe.
Code Case N-522, Pressure Testing of Containment Penetration Piping has been found acceptable for use.
Note: Conditions established for use of this Code Case require that the licensee perform the leak test at the peak calculated containment pressure and use a test procedure that provides for detection and location of through-wall leakages in the pipe segments being tested.
Request for Relief DOC-l, proposes an alternative to Code recording and reporting requirements.
Code Case N-532, Alternative Requirements to Repair and Replacement Documentation.
Requirements and Inservice Summary Report Preparation and Submission as Required by NA-4000 and Ih(A-6000 has been found
,acceptable for use as written. It should be noted that administrative burdens are not considered a basis for relief.
S.
Verify that there are no requests for relief in addition to those submitted.
If additional requests for.relief are required, they should be submitted for staff review.
The schedule for timely completion of this review requires that the licensee
- provide, by the requested
- date, the above requested information and/or clarification with regard to the Diablo Canyon Power Plant, Units 1 and 2, Second 10-Year Interval Inservice Inspection Program Plan, Revision 0.
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