ML20023B342
| ML20023B342 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 02/25/1983 |
| From: | Battelle Memorial Institute, PACIFIC NORTHWEST NATION |
| To: | NRC |
| Shared Package | |
| ML20023B345 | List: |
| References | |
| CON-FIN-B-2157 NUDOCS 8303220042 | |
| Download: ML20023B342 (29) | |
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TECHNICAL EVALUATION REPORT MAINE YA'1KEE ATOMIC POWER PLANT INSERVICE INSPECTION PROGRAM i
Submitted to:
U.S. Nuclear Regulatory Commission Fin. B2157 Battelle, Pacific Northwest Laboratory Richland, Washington
_ February 25, 1983 XAMjHos Been Sent to PDR f
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'i TECHNICAL EVALUATION REPORT MAINE YANKEE ATOMIC POWER PLANT INSERVICE INSPECTION PROGRAM The revision to 10 CFR 50.55a, published in February 1976, required that Inservice Inspection. (ISI) Programs be updated to meet the requirements (to the extent practical) of the Edition and Addenda of Section XI of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (hereinafter referred to asSection XI or Code) incorporated in the Regulation by reference in paragraph (b).
This updating of the programs was required to be done every 40 months to reflect the new requirements of the later editions of Section XI.
As specified in the February 1976 revision, for plants with.
Operating Licenses issued prior to March 1, 1976, the regulations became effective after September 1, 1976, at the start of the next regular 40-month inspection period.
The initial inservice examina-tions conducted during the first 40-month period were to comply with the requirements in editions of Section XI and addenda in effect no more than six months prior to the date of start of facility commercial operation.
The Regulation recognized that the requirements of the later editions and addenda of the Section XI might not be practical to implement at facilities because of limitations of design, geometry, and materials of construction of components and systems. It therefore
-permitted determinations of impractical examination or testing re-quirements to be evaluated. Relief from these requirements could be granted provided health and safety of the public were not endangered, giving due consideration to the burden placed on the licensee if the requirements were imposed.
The licensee, Maine Yankee Atomic Power Company, of the Maine Yankee Atomic Power Plant, has recently sub-mitted relief requests dealing with inservice examinations of com-ponents or with system pressure tests that were formally submitted'to the Nuclear Regulatory Commission (NRC). Inservice tests of pumps and valves (IST programs) are being evaluated separately.
The revision to 10 CFR 50.55a, effective November 1,
- 1979, modified the time interval for updating ISI programs and incorporated by reference a later edition and addenda of Section XI.
The updating intervals were extended from 40 m.cr.ths to 120 months to be consistent with intervals as defined i. 8ection XI.
For plants with Operattag Licenses issued prior to March 1,1976, the provisions of the November 1,1979, revision are effective af ter September 1,1976, at the start of the next one-third of the 120-month interval.
During the one-third of an interval and throughout the 1
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remainder of the interval, inservice examinations shall comply with the latest edition and addenda of Section XI, incorporated by refer-ence in the Regulation, on the date 12 months prior to the start of that one-third of an interval. For Maine Yankee, the ISI program and relief requests submitted in conjunction with it cover the last 40 months of the current 120-month inspection interval, i.e.,
from August 28, 1979, to December 28, 1982.
This program was based upon the 1974 Edition of Section XI of the ASME Boiler and Pressure Vessel Code with Addenda through the Summer of 1975.
The November 1979 revision of the Regulation also provides that ISI programs may meet the requirements of subsequent Code editions and addenda, incorporated by reference in paragraph (b) and subject to NRC approval. Portions of such editions or addenda may be used, provided that all related requirements of the respective editions or addenda are met.
Finally,Section XI of the Code provides for ce::tain components and systems to be exempted from its requirements.
In some instances, these exemptions are not acceptable to NRC or are only acceptable with restrictions.
References (1) to (11) listed at the end of this report pertain to previous information transmittals on ISI between the licensee and the Commission.
By letters of April 22 and November 17, 1976,(1,3) the Commission provided general ISI guidance to all licensees.
Submittals in response to that guidance were made by the licensee on May 13,1976, (2) ber 4 and 21,1979. (6,7) y 15,1978, (4) March 28,1979, (5)
Februar and Septem-In the ISI program submitted with References 6 and 7, provision was made in the content to include relief requests but none was included.
On March 23, 1982,(8) the Commission requested the following from the licensee:
(a) revision to the technical specifications in accordance with the November 1,
1979, change in 10 CFR 50.55a(g)
(4) (ii), (b) status of relief requests, and (c) concurrence with the Commission's position on adoption of Appendix III of Section XI (as related to recording of flaw indications). On April 30, 1982,(9) the licensee indicated that Item (c) would be incorporated into the ISI program prior to the next Inservice Inspection and that the technical specifications would be revised.
The proposed technical specifica-tion revision submitted May 27, 1982,(10) includes the provision that relief requests shall be submitted to the Commission for their review and approval no later than 12 months after the expiration of the inspection interval in which the examination or test is determined to be impractical. This provision is in accordance with the terms of the regulation (10 CFR 50.55a(g) (5) (iv)) but not with the practice of the Commission. The Commission has been encouraging licensees, generally successfully, to submit relief requests before or during the examina-tion process rather than after the expiration of the inspection 2
interval. In that way, the Commission's requirements for alternative i
examination can be anticipated and scheduled by the licensee.
The relief requests were submitted to the NRC as part of Revision 2 to Maine Yankee's Inservice Inspection and Testing Program (11) on Octo-ber 12, 1982.
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CLASS 1 COMPONENTS A.
Reactor Vessel 1.
Request for Relief No.
1, Circumferential and Meri-dional Welds in Vessel Heads, Category B-B, Item Bl.2 Code Requirement Perform volumetric examination of 10% of head meridional welds and 5% of circumferential head welds.
Code Relief Request Perform volumetric examination of closure head and lower head welds where access and geometry permit.
Proposed Alternative Examination None Licensee's Basis for Requesting Relief The Code required volume cannot be met because of the interference of the instrument tubes in the lower head.
The instrument penetrations prohibit the scan arm of the inspection equipment from adequately cov-ering the required volumes.
The closure head has a shroud, insulation, and CRD drives ~ mounted such that access to the head-to-dome weld and portions of the meridional welds are not accessible.
Evaluation The design of the reactor vessel prohibits access to the welds from the exterior by the control rod drive penetrations and from the interior by the core shroud plate.
Conclusions and Recommendations Based on the above evaluation, it is concluded that for the welds discussed above, the Code require-ments are impractical.
As an alternative, however, the licensee should be required to visually examine the area for leakage after the vessel hydrostatic examination.
It is recommended that this request be granted, providing the licensee visually examines the areas of interest during vessel hydrostatic test.
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2.
Request for Relief No.
2, Nozzle to Vessel Welds, Category B-D, Item Bl.4 Code Requirement Examine all nozzles each interval, using volum-
.etric methods.
Code Relief Request Relief is requested from the requirements of IWB-2512* which require inspections of the nozzle to vessel welds during each period of the inspection interval.
Proposed Alternative Examination The requirements of Category B-D will be ful-filled at the end of each inspection interval during the full vessel examinations.
Licensee's Basis for Requesting Relief The examinations are fully performed during the tenth-year examination.
Exams performed during the intermediate periods are either partially performed from the 00, with a large man-rem burden, or from the ID by using a remote device such as a RAR tool.
This is also a high rem burden test.
Additionally, latter editions of. ASME Section XI provide for Category B-D exams at the end of each interval.
Evaluation Later Code editions recognized the dif ficulty of examining nozzle welds in each period and now permit these examinations to be carried out at the end of the interval with no significant decrease in safety.
Conclusions and Recommendations Based on the above evaluation, it is concluded that the Code requirements are impractical.
It is further concluded that the alternative examinations proposed by the licensee will provide the necessary
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assurance of structural reliability.
It is recom-mended that this request be granted.
3.
Request for Relief No. 3, CRD Housf.ng Welds, Category B-O, Item Bl.18 Code Requirement The examination of 10% of the peripheral control 1
rod housing retaining welds shall be performed once per interval.
Code Relief Request Perform a liquid penetrant exam on all CRD hous-ing welds when the CRD drive assemblies are removed for maintenance or inspection.
Proposed Alternative Examination Perform a surface exam in lieu of a volumetric exam of the CRD pressure boundary welds according to the maintenance and disassembly schedule of the CRD housings.
Licensee's Basis for Requesting Relief It is impractical to remove and disassemble a CRD housing to perform only an examination of a pressure boundary weld. The volumetric criteria was deleted in later editions of the inspection Code in lieu of a surface exam.
A maintenance schedule based on need will provide sufficient schedule for these examina-tions.
Evaluation In later Code editions, the plant owner has the option of performing volumetric or surface examina-tion of CRD housing welds, as the surface method has been determined to be a satisfactory means of assuring CRD housing weld integrity.
The portion of the Code specifying peripheral housings for examination is for the convenience of plant owners.
Conclusions and Recommendations Based on the above evaluation, it is concluded that the Code requirements are impractical.
It is further concluded that the alternative examinations 6
proposed by the licensee will provide the necessary assurance of structural reliability.
It is recom-mended that this request be granted, provided that the required number of CRD housings are examined before the end of the inspection interval.
4.
Request for Relief No. 4, Vessel Cladding, Category B-I-1, Items Bl.13 and Bl.14 Code Requirement Perform visual and surface or volumetric examin-ation of six (6) clad patches each on the interior at l
the closure head and the vessel.
Code Relief Request Perform 100% visual exam of the interior of the closure head once per interval. Perform a visual exam of the cladding of the vessel when performing B-N-3 exams.
Proposed Alternative Examination 100% visual exam of the interior surfaces of the closure head and visual exam of cladding during the B-N-3 exams.
Licensee's Basis for Requesting Relief Required examinations have proven of little sig-nificance in detecting cladding cracks. Visual exam-ination of 100% of the head will provide a crack indication by showing a dry boric acid mark against the very dark appearance of the head ID. The requirements for the vessel patches are not possible because of the high radiation environment. Additionally, both items were deleted or changed in the later Codes.
Evaluation Subsequent Editions and Addenda of Section XI have deleted the examination requirements of Category B-I-l entirely since these Editions and Addenda of Section XI are referenced by 10 CFR 50.55a.
The licensee should be allowed to update his inspection program to reflect the deleted requirement.
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Conclusions and Recommendations Based on the above evaluation, it is concluded that the Code requirements are impractical.
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further concluded that the alternative examinations proposed by the licensee will provide the necessary l
assurance of structural reliability.
It is recom-mended that this request be granted.
5.
Request for Relief No.12, Integrally Welded Supports
( All Systens), Categories B-H, B-K-1, and B-K-2, Items Bl.12, B3.7, B4. 9,- B4.10, B5. 4, B5. 5, B6. 4 and B6. 5 Code Requirements B-H'- In the case of vessel support skirts, the examirration performed during each inspection interval shall cover, at least,10% 'of the circumference of the weld to - the vessel.
In the case of support lug attachments, 100% of the welding to the vessel shall be examined.
B-K The examinations performed during each inspection interval shall cover 25% of the integrally-welded supports.
B-K The examination performed during each inspection interval'shall cover.all. support compon-
- ents.
i The support settings of constant and variable spring type hangers, snubbers, and shock absorbers shall be verified.
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Code Relief Request Relief is. requested from performing the'volum-etric examination of welds on supports.
Proposed Alternative Examination To perform the Alternate Surface Examination given in-the 1977 Code.
3 Licensee's Basis for Requesting Relief-1 The support welds are partial penetration welds and coupled with the configurati' ns of support design, o
we do not feel a meaningful volumetric examination can be performed.
Additionally, per 1977 Code,Section I
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f XI, either a surface or a volumetric examination may be performed.
Evaluation t
The components in Category B-K-2 do not require a volumetric examination at all, so they should not be a part of this request.
The Category B-H and B-K-1
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welds are partial penetration welds that do not lend themselves to volumetric examination.
Surface exam-inations do provide assurance of structural reliabil-ity for these welds.
Conclusions and Recommendations Based on the above evaluation, it is concluded that for the Category B-H and B-K-1 welds, the Code requirements are impractical. It is further concluded that the surface examinations proposed by the licensee will provide the necessary assurance of structural reliability.
The following is recommended:
1)
Grant the request for Categories B-H and B-K-1.
2)
Do not grant the request for Category B-K-2 as relief is not required for this Category.
B.
Pressurizer None C.
Heat Exchangers and Steam Generators See I.A.S.
D.
Piping Pressure Boundary 1.
Request for Relief No. 5, Safe-End Welds, Category B-F, Item B4.1 Code Requirement Perform a surface / volumetric exam of the dis-similar metal weld once per interval.
Code Relief Request Relief / is requested from the volumetric examina-tion of th'e SA351-CF8M portion of the dissimilar metal fweld.
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1-Proposed Alternative Examination Perform an ultraconic exam from the nozzle side-of the weld on the ferritic material.
Perform the required surface exams.
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Licensee's' Basi:4 for Requesting Relief The material of the safe-end is SA351-CF8M cast stainless steel.
This material does not allow mean-ingful ultrasonic test results because ~of the large columnar grain structure. RT is not practical because the line.is water filled which would require a high energy source.
Thers high energy x-ray machines are
- only in the developmental stages.
Evaluation
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,T' The current state of the art in ultrasonic test-6
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,ing does not permit meaningful examinations of cast
!}isystems.
>stpinless steels. typically found in nuclear steam See'rpfdrence (13) for further details on t
this subfect.
These materials' fracture toughness' i
properties are such that a through wall tiefect would
,,e lead (to a readily detectable leak well before the s
component would completely fracture.
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.CbnckUsions and Recommendations r>
i Based on the above evaluation, it is concluded the Code requirements are, ~ impractical.
It is fthat
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further concluded that the alternative examinations
!u proposed by the licensee will. provide the necessary Lassurance of structural reliability.
It is recom-
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p, mended that this request be granted.
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Request-for Relief No.10, Nozzle to Safe-End and Safe-End to Pipe Welds, Category B F, Item B4.1 Code Requirement.
"The volumetric... examinations performed dur-
-ing each inspection interval shall include 100% of those dissimilar metal weldsiin the piping runs sel-ected for examination..."
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Code Relief Request Relief is requested from the volumetric portion of a dissimilar metal weld exam where the ultrasonic beam must pass through the cast stainless steel mate-rials of the safe-end.
This relief is required only when the material specification lists SA351-CF8M, SA451-CPF8M.
Proposed Alternative Examination
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The required surface examination will be per-formed.
Maine Yankee will also continue to evaluate new techniques being developed by the industry.
Licensee's Basis for Requesting Relief The cast stainless steel materials defined by the material specification SA351 and SA451 are large col-umnar grained materials which impair meaningful ul-trasonic examination. The material adjacent to these safe-ends is acceptable to ultrasonic examination. A valid examination can be performed on the foging side of the safe-end and on the pipe run side.
This exam will cover the base material and neat affected zones leaving only the tougher weld metal and cast stainless material uninterrogated by the ultrasonic beam.
Evaluation The current state of the art in ultrasonic test-ing does not permit meaningful examinations of cast stainless steels typically found in nuclear steam systems.
See reference (13) for further details on this subject.
These materials' fracture toughness properties are such that a through wall defect would lead to a readily detectable leak well before the component would completely fracture.
Conclusions and Recommendationt Based on the above evaluatior., it is concluded that the Code requirements are impractical.
It is further concluded that the alternative examinations proposed by the licensee will provide the necessary assurance of structural reliability.
It is recom-mended that this request be granted.
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I 3.
Request for Relief No. 7, Circumferential and Branch Connection Welds, Category B-J, Items B4.5 and B4.6 Code Requirement Examine 25% of the total number of welds per interval using volumetric methods.
Code Relief Request Relief is requested from the volumetric examina-l tion of the Category B-J welds.
Proposed Alternative Examination s
surface method at the intervals required by Category B-J.
Radiographic testing if the line is drained.
Licensee's Basis for Requesting Relief The lines are fabricated from SA451-CPF8M mate-rial.
This is of cast stainless steel with a large columnar grain structure.
This structure does not provide, meaningful ultrasonic examinations.
In addi-tion, those lines are not drained during a refueling outage.
This would require radiography of a 8"/12" water filled pipe.
The high energy RT sources avail-able to do this work are in the developmental stage.
i Maine Yankee-will evaluate future development and implement them when they are practical.
i Evaluation The current state of the art-in ultrasonic test-ing does not permit meaningful examinations of cast stainless steels typically found in nuclear steam '
systems.
See reference (13) for further details on i
this subject.
These materials' fracture toughness properties are such that a through wall defect would lead to a readily detectable leak well before the component would completely fracture.,
i Conclusions and Recommendations Based on the above evaluation, it is cuncluded that the Code requirements are impractical.
It:is further concluded that the alternative examinations proposed by the licensee will provide the necessary assurance of structural reliability.
It is recom-mended that this request be granted.
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Pump Pressure Boundary 1.
Request for Relief No. 9, Main Recirculation Pump to Isolation Valve Weld, Category B-J, Item B4.5 Code Requirement Perform an examination of 100% of the weld per examination interval using a volumetric technique.
Code Relief Request Relief is requested from the volumetric examina-tion of this weld.
Proposed Alternative Examination Maine Yankee will evaluate the use of high energy radiography and perform exams using this technique when they are practical.
In lieu of this Code re-quirement, the welds will be examined using surface methods and be subjected to pressure testing per ASME Section XI schedules.
Licensee's Basis for Requesting Relief Relief is requested from the volumetric examina-tion of this weld because methods do not exist for meaningful ultrasonic examination of cast stainleas steel (SA351-CF8M).
The geometry of this weld joint is not consistent with good ultrasonic practice, gam ta radiography of this material at the thickness ar.A distances is not practical, and high energy sourcc:.
are on a one of a kind basis.
Evaluation The current state of the art in ultrasonic test-ing does not permit meaningful examinations of cast stainless steels typically found in nuclear steam systems.
See reference (13) for further details on this subject.
These materials' fracture toughness properties are such that a through wall defect would lead to a readily detectable leak well before the component would completely fracture.
Conclusions and Recommendations Based on the above evaluation, it is concluded that the Code requirements are impractical.
It is 13
further concluded that the alternative examinations proposed by the licensee will provide the necessary assurance of structural reliability.
It is recom-mended that this request be granted.
2.
Request for Relief No.
8, Main Coolant Pump Casing Welds, Categories B-L-1 and B-L-2, Items B5.6 and B5. 7 Code Requirement The examinations performed during each inspec-tion interval shall include 100% of the pressure-retaining welds in at least one pump in each group of pumps performing similar functions in the system. The examinations required are volumetric and visual.
Code Relief Request Defer the volumetric examination and visual exams of the pump casing welds until the pumps are fully disassembled for maintenance.
At this time, evaluate the ability to perform a meaningful volum-etric exam using either advanced ultrasonic tech-niques or high energy radiography.
Proposed Alternative Examination Defer the B-L-1 and B-L-2 exams until the pump is dismantled for maintenance.
Perform the B-L-2 exams at that time and evaluate, and, if practical, perform the volumetric exams required by B-L-1.
Licensee's Basis for Requesting Relief The pump casings are made of SA351-CF8M material.
This cast stainless steel has the large columnar grain structure which prohibits meaningful ultrasonic exam-ination.
The pump and associated piping are in high radiation areas which could reduce the quality of radiography by severe fogging. The limited ability to inspect the casings is of tset by the inherent fracture toughness of this material, and cast stainless steel casings in general. The service history of these pumps shows no reason to anticipate a service-induced weld failure, and, of the pumps examined to date, no evid-ence of failure has been observed.
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i' Evaluation The current state of the art in ultrasonic test-ing does not permit meaningful examinations of cast stainless steels typically found in nuclear steam systems.
See reference (13) for further details on this subject.
These materials' fracture toughness properties are such that a through wall defect would lead to a readily detectable leak well before the component would completely fracture.
Conclusions and Recommendations Based on the above evaluation, it is concluded that the Code requirements are impractical.
It is further concluded that the alternative examinations proposed by the licensee will provide the necessary assurance of structural reliability.
It is recom-mended that this request be granted.
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Valve Pressure Boundary 1.
Request for Relief No. 6, Isolation Valve to Safe-End and Safe-End to Pipe Welds, Categories B-F and B-J, Items B4.1 and B4.5 Code Requirement B-F - Volumetric and surface exam of 100% of the weld each inspection interval.
B-J - Volumetric exam of 25% of the total welds each inspection interval. Exam shall include examin-ation of 100% of each weld.
Code Relief Request Relief is requested from the volumetric examina-tions of the valve to safe-end and safe-end to pipe weld.
Proposed Alternative Examination The safe-end to pipe weld will be examined using ultrasonic techniques from the pipe side of the weld joint. Additionally, the weld surf aces (B-F and B-J) will be examined using a surface technique.
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i Licensee's Basis for Requesting Relief The material specification of the valve body is SA351-CF8M.
The specification of the safe-end mate-rial is SA451-CPF8M.
Both materials are cast stain-less steel which have a large columnar grain struc-ture. This structure prohibits meaningful UT examin-ation. Radiographic examination of these welds would require a high energy source capable of penetrating 7" of steel and 33" of water.
At the present time, this source is only developmental. Should a practical high energy source become commercially available, Maine Yankee will participate in its evaluation and use.
Evaluation
.The current state of the art in ultrasonic test-ing does not permit meaningful examinations of cast stainless steels typically found in nuclear steam systems.
See reference (13) for further details on this subject.
These materials' fracture toughness properties are such that a through wall defect would lead to a readily detectable leak well before the component would completely fracture.
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. Conclusions and Recommendations Based on the above evaluation, it is" concluded that the Code requirements are impractical.
It is further concluded that the alternative examinations proposed by the licensee will provide the necessary assurance of structural reliability.
It is recom-mended that this request be granted.
2.
Request for Relief No.11, Valve Bodies and Valve Body Welds, Categories B-M-1 and B-M-2, Items B6.6 and B6. 7 Code Requirements The examinations performed during each inspec-tion interval shall include 100% of the pressure-retaining welds in at least one valve within each group of valves that are of the same constructional design (e.g., globe, gate, or check valvle), manufacturing method and manufacturer and that are performing simi-lar functions in the system (e.g., containment isola-tion,. system overpressure protection, etc.).
The examinations required are volumetric and visual per Item B6.6 and Item B6.7 of IWB-2600.
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Code Relief Request Defer the volumetric examination and visual exams of the valve casing welds until the pumps are fully disassembled for maintenance.
At this time, evaluate the ability to perform a meaningful volum-etric exam using either advanced ultrasonic tech-niques or high energy radiography.
4 Proposed Alternative Examination Defer the B-M-1 and B-M-2 exams until the valve is dismantled for maintenance.
Perform the B-M-2 exams at that time and evaluate, and, if practical, perform the volumetric exams required by B-M-1.
Licensee's Basis for Requesting Relief The valve casings are made of SA351-CF8M mate-rial. This cast stainless steel has the large columnar grain structure which prohibits meaningful ultrasonic examination.
The valve and associated piping are in high radiation areas which could reduce the quality of radiography by severe fogging. The limited ability to inspect the casings is offset by the inherent fracture toughness of this material, and cast stainless steel casings in general.
The service history of these valves shows no reason to anticipate a service-induced weld failure, and, of the valves examined to date, no evidence of failure has been observed.
Evaluation The current state of the art in ultrasonic test-ing does not permit meaningful examinations of cast stainless steels typically found in nuclear steam systems.
See reference (13) for further details on this subject.
These materials' fracture toughness properties are such that a through wall defect would lead to a readily detectable leak well before the component would completely fracture.
Conclusions and Recommendations l
Based on the above evaluation, it is concluded that the Code requirements are impractical.
It is i
further concluded that the alternative examinations proposed by the licensee will provide the necessary assurance of structural reliability.
It is recom-mended that this request be granted.
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f II.
CLASS 2 COMPONENTS A.
Pressure Vessel Welds 1.
Requests for Relief Nos. 13, 14, 15, 16, 17, 18, 19, I
and 20, Chemical and Volume Control and Reactor Cool-ant Systems, Category C-A, Item Cl.1 Code Requirement The examinations shall cover at least 20% of each circumferential weld, uniformly distributed among i
three areas around the vessel circumference.
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Code Relief Request Relief is requested from performing the volum-etric examinations of welds.
Proposed Alternative Examination Perform a visual inspection during system hydro-static pressure and leak testing.
Licensee's Typical Basis for Requesting Relief Per Section XI,1977 Code,* IWC-1220d, component connections, piping, and associated valves and ves-sels (and their supports) that are 4" nominal pipe size and smaller. Piping to and from this system component (E-67) is 4"
and less.
A failure of this systen component should be no greater than the failure of the system piping.
Additionally, due to the high radi-ation levels; i.e., cubicle area is 3-5 R/hr. Compon '
ent contact is 1-10 R/hr.
Evaluation All eight of these Class 2 relief requests are based on the same premise; that is, that since no lines greater than 4" diameter are attached to the vessels, even if the vessel fails completely, the resulting leak would be no greater than that from a failed 4" line.
Therefore, it is reasoned that these vessel
- Licensee apparently meant to refer to the 1974 Edition rather than the 1977 Edition as the 1977 Edition does not contain subparagraph 1220(d) and this plan was written in accordance with the 1974 Edition.
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welds should be exempted from volumetric examina-tions. The vessels involved in this request include:
Volume Control Tank (TK-6), Letdown Heat Exchanger (E-44), Regenerative Heat Exchanger (E-67), Seal Water Heater (E-96), Seal Water Supply Filters (FL-34A and FL-3 4 B), Letdown Pre-Filter (FL-35A), Purification j
Demineralizers (I-2A, I-2B, I-2C), and Deborating l
Demineralizer (I-3).
These are thin-walled vessels that are difficult to volumetrically examine.
Conclusions and Recommendations Based on the above evaluation, it is concluded that the Code requirements are impractical.
It is further concluded that the alternative examinations proposed by the licensee will provide the necessary assurance of structural reliability.
It is recom-mended that this request by granted.
l III. PRESSURE TEST RELIEF REQUESTS A.
Safety Class 1, 2, and 3 Systems 1.
Request for Relief No. 21, Chemical and Volume Control System, Components CH-24, CH-25, CH-26, and CH-27 Code Requirement Subparagraph IWC-5220 ( a) - "The System Hydro-static Test pressure shall be at least 1.25 times the system design pressure (P )*"
D Proposed Alternative Test The recirculation lines will be included in the hydrostatic test boundary for the suction side piping.
The test pressure is 188 psig (1.25 x 150 psig).
Licensee's Basis for Requesting Relief The charging pump recirculation lines listed above have a design pressure of 2750 psig.
There are no test connections which would permit these lines to be tested while isolated from the suction side of the charging pumps. The charging pump suction piping has a design pressure of 150 psig and would be over-pressurized if exposed to the pressure of 3438 psig, which is 1.25 times the recirculation line design pressure.
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l Evaluation Because of system design, the possibility of overpressurizing portions of the system makes the Code requirement impractical. Portions of this system will be subjected to other nondestruct_ive examinations as well as visual examination at' operating pressure.
These examinations will provide assurance of the structural integrity of the system.
Conclusions and Recommendations Based on the above evaluation, it is concluded that the Code requirements are impractical.
It is further concluded that the alternative testing pro-posed by the licensee provides an adequate level of safety. It is recommended that this request for relief be granted.
2.
Request for Relief No. 22, Safety Injection System, Line(s)/ Component (s) SIH-20, SIH-22, SIE-24, SIH-30, SIH-31, SIH-3 3, SIH-34, SIH-41, SIH-4 2, RC-4 8, RC-4 9, RC-50, RC-51, RC-52, and RC-53 Code Requirement Paragraph IWB-5210 "The componente shall be subjected to (a) a system leakage test prior to startup following each reactor refueling outage."
Proposed Alternate Test None Licensee's Basis for Requesting Relief The lines listed above are not subjected to full Reactor Coolant System pressure during the Reactor Coolant System leak test. The design of the system is such that there are two check valves installed in the safety injection lines for each loop to prevent over-pressurization of the upstream lower pressure resi-dual heat removal lines.
These lines are subject to volumetric examination in accordance with the re-quirements of IWB-2000 and are subject to periodic hydrostatic testing at or near the end of the inspec-tion interval in accordance with Paragraph IWA-5210.
20
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Evaluation The system design is such that these lines are not pressurized during a system leakage test, but they are pressurized during hydrostatic testing. They are also subject to volumetric examinations during the inspec-i tion interval.
Conclusions and Recommendations Based on the above evaluation, it is concluded that the Code requirements are impractical.
It is t
further concluded that other tests performed by the licensee will provide an adequate level of safety.
It is recommended that this request for relief be granted.
3.
Request for Relief No. 23, Chemical and Volume Control System-Seal Water Return from the Reactor Coolant 3
Pumps, Safety Class 2/3, Line(s)/ Component (s):
CH-7 7, CH-81, CH-8 2, CH-83, CH-92, CH-95, CH-24 9, CH-251, CH-253, CH-255, CH-257, CH-258, DRL-121 and DRL-122 Code Requirement 4
Paragraph IWD-1200 "The examination require-ments of IWD shall apply to Class 3 pres.mure retaining components (and their suppor ts). "
Proposed Alternate Test-None Licensee's Basis for Requesting Relief The Seal Water System was classified as Safety Class 3 based on ANSI N18.2-1973.
Due to the design of the reactor coolant pump seals, however, it has been determined that the return lines (listed-above) are not required for the functioning of " Components Im-portant to Safety" (i.e., the reactor coolant pumps),
which is the criterion used to classify components as Quality Group C under Regulatory Guide 1.26. A failure of any of these lines would not necessitate the shut-down of the reactor coolant pumps or significantly affect plant safety.
Therefore, these lines are functionally NNS and are exempt from testing.
See Relief Request 27 for the basis for exempting the Class 2 portions between containment isolation valves from testing.
21 7
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i-Evaluation According to the classifications of Regulatory Guide 1.26, these lines are non-nuclear systems and are therefore not subject to'the tests of Paragraph IWD-1200 of the Code.
Conclusions and Recommendations Based on the above evaluation, it is concluded that no increase in safety would result from testing these lines.
It is recommended that this request for relief be granted.
4.
Request for Relief No. 24, Various Class 2 Systems j
Code Requirement-t Subparagraph IWC-5220(a) states that hydrosta-tic tests shall be " conducted at a test temperature not less than 1000F except as may be required to meet test i
temperature requirements of IWA-5230."
Proposed Alternate Test None Licensee's Basis for Requesting Relief A method does not exist at Maine Yankee for 3
preheating. water being used to fill and hydrostatic-ally test a system. Where systems are constructed of ferritic steel and the temperature of the contained fluid is mandated by fracture prevention criteria, the contained fluid will be heated by normal system heat-up methods prior to performing the test.
Where the system is constructed of austenitic steel, no limit on system temperature will be imposed. This position is consistent with Paragraph IWC-5230, as it appears in
.the 1980 Edition of Section XI, which has been accepted by the NRC.
Evaluation 1
The 1980 Edition of the Code allows hydrostatic testing of austenitic steel lines without a tempera-ture limit.
10 CFR 50.55a(g) (1) allows the option of adopting subsequent Editions and Addenda of the Code.
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l Conclusions and Recommendations i
Based on options presented in 10 CFR 50.55a (g) (1), it is recommended that this request for relief be granted.
5.
Request for Relief No. 25, Lines on Discharge Side of Centrif ugal Pumps, RH-7, RH-8, RH-9, RH-10, RH-ll, RH-12, CS-21, CS-22, CS-23, CS-24, CS-25, CS-26, CH-20, CH-21, CH-22, CH-24, CH-25 and CH-26 Code Requirement Subparagraph IWC-5220 ( a)
"The system hydro-static test pressure shall be at least 1.25 times the system design pressure (P ) "
l D
Proposed Alternate Test Piping on the discharge side of centrifugal pumps, up to the first isolation valve, will be tested to the hydrostatic test pressure required for the suction side of the pump where the pressure ratings on the suction and discharge of the pump differ.
Licensee's Basis for Requesting Relief The lines listed above are on the discharge side of the various centrifugal charging pumps.
In each case, these lines have higher design pressures than the pump suction side lines.
In order not to subject the pump suction lines to excessive pressure which could damage them, the hydrostatic boundary between the high and low pressure will be the first isolation valve on the discharge side of the pump. This position is consistent with Subparagraph IWA-5224(d), as it appears in the 1980 Edition of Section XI, which has been accepted by the NRC.
Evaluation Later editions of the Code recognized a problem with hydrostatically testing systems containing a centrifugal pump.
These later editions allow the hydrostatic boundary to be placed at the first isola-tion valve on the discharge side of the pump to prevent damage to lines on the suction side.
23
Conclusions and Recommendations Based on the above evaluation, it is concluded that the Code requirements are impractical.
It is further concluded that compliance with the 1980 Edi-tion of the Code will provide an adequate level of safety. It is recommended that this request for relief be granted.
6.
Request for Relief No. 26, Various Class 2 and 3 Non-insulated Systems and Components Code Requirement Subparagraph IWA-5210(a) - "The test pressure and temperature shall be maintained for at least four hours prior to the performance of the examinations."
Proposed Alternate Test None Licensee's Basis for Requesting Relief Section XI, 1974 Edition through Summer 1975 Addenda, requires a hold time for System Pressure tests of four hours whether or not the system is insulated. The purpose of this time is to provide for leakage to penetrate the insulation on the line and accumulate so that it can be readily detected visu-ally.
In the case where a line or component is not insulated, this extra hold time is not required.
The re for e, for systems and components which are not insulated, the required hold time for test temperature and pressure will be only 10 minutes.
This position is consistent with Subparagraph IWA-5713(d) as it appears in the 1977 Edition (including Addenda through the Summer 1978) of Section XI, which has been accepted by the NRC.
Evaluation The objective of the Code requirement was to provida sufficient time for leakage from cracks to penetrate installed insulation before the visual ex-amination.
For exposed piping, 10 minutes should be sufficient to meet the intended objective.
24
Conclusions and Recommendations Based on the above evaluation, it is concluded that the Code requirements are impractical and that the test method proposed by the licensee will provide l
an adequate level of safety.
It is recommended that this request for relief be granted.
7.
Request for Relief No. 27, Various Class 2 Portions of Systems at Containment Penetrations between Class 3 or Non-Nuclear Class Components SAFETY LINE/ COMPONENT DRAWING SAFETY EXAMINE "PER" PCC-147, 148, 154, FM-34C 2
Subarticle IWD, 157, 167, 169, Functionally.
186, 192, 194-Class 3 200, 237, 238, 242-246, 251-265, 270- 280, 282, 284-290, 370, 372 GN-2 FM-29A 2
No Examination Required, Func-tionally NNS VRL-39 FM-33A 2
No Examination Required, Func-tionally NNS RWL-1 FM-40A 2
No Examination Required, Func-tionally NNS VL-22 FM-33B 2
No Examination Required, Func-tionally NNS CH-82, 83, 77, FM-31A 2
No Examination 81, 89, 255, Required, Func-DRL-121, 122 tionally NNS Code Requirement Paragraph IWC-1210 - "The examination require-ments of IWC shall apply to Class 2 pressure-retaining components (and their supports). "
25 1
l l
l
t 4.
Proposed Alternate Tests See Table above.
Licensee's Basis for Requesting Relief Those portions of process piping that serve as part of the containment boundary are constructed to meet the rules for Class 2 components.
The process system functions, however, would require that these components be classified as Class 3 or non-nuclear class.
The system pressure tests required by Section XI are intended to detect service-induced degradation of systems based upon the operational loads that a com-ponent is expected to sustain over its service life-time; therefore, the application of Section XI rules should be in accordance with the process system func-tion. Containment leak tightness is the subject of a separate series of tests. This position is consistent with Subparagraph IWA-1300 (f), as it appears in the 1980 Edition of Section X1, which has been accepted by the NRC.
This subparagraph states:
"The portion of piping that penetrates a containment vessel, which is required by Section III to be constructed to Class 1 or 2 rules for piping and which may differ from the classification of the balance of the piping system, need not affect the overall system classification that determines the applicable rules of this section."
Accordingly, where the components beyond the contain-ment penetration are classified as Class 3, the Class 2 process piping will be examined in accordance with the rules of Subsection IWD of Section XI.
Where the components beyond the penetration area are classified as non-nuclear class, the Class 2 piping will be considered exempt from the requirements of Section XI.
Evaluation Since the NRC has approved the 1980 Edition of Section XI and allowed licensees the option of adopt-ing subsequent approved Editions and Addenda of the Code, this request for relief is valid.
Conclusions and Recommendations Based on the above evaluation, the Code require-ments are inconsistent. It is recommended that relief be granted.
26 l
8.
Request for Relief No. 28, Main and Auxiliary Feed-water System, Lines WFPD-3, WFPD-4, WFPD-7, WFPD-8, WFPD-9, WFPD-10, WFPD-15, WPFD-16, WFPD-17, WAPD-21, WAPD-23, and WAPD-25 Code Requirement Subparagraph IWC-5220(A) - "The system hydro-static test pressure shall be at least 1.25 times the system design pressure (Po). "
Proposed Alternate Test The main and auxiliary feed lines listed will be tested to 1230 psig (1.25 x 985 psig) along with the steam generators and main steam lines.
Licensee's Basis for Requesting Relief There is no isolation valve between the main and auxiliary feed lines listed above and the associated I
steam generators. The design pressure of the lines is 1250 psig (normal operating pressure is 1000 psig),
but the design pressure for the steam generators is only 985 psig.
Therefore, the feed lines cannot be tested to the Code required 1560 psig without over-pressurizing the steam generators and main piping.
Evaluation Because of the design of the system, the possi-bility of overpressurizing portions of the system makes the Code requirement impractical.
Portions of this system will be subjected to other nondestructive examinations as well as visual examination at operat-ing pressure. These examinations will provide assur-ance of the structural integrity of the system.
Conclusions and Recommendations Based on the above evalitation, it is concluded that the Code requirements are impractical.
It is further concluded that the alternative testing pro-posed by the licensee provides an adequate level of safety. It is recommended that this request for relief be granted.
27
REFERENCES 1.
R. A.
Purple (NRC) to R. H. Groce (YAEC), April 22, 1976.
2.
J.
L. French (MYAPC) to R. A.
Purple (NRC), May 13, 1976.
3.
R. W. Reid (NRC) to R.
H. Groce (MYAPC), November 17, 1976.
4.
W.
P. Johnson (MYAPC) to NRC, Office of Nuclear Reactor Regula-tion, Inservice Inspection Program, WMY-78-14, February 15, 1978.
5.
D.
E.
Vandenburgh (MYAPC) to NRC, Office of Nuclear Reactor Regulation, Revision to MY Inserivca Inspection Technical Spe-cifications, WMY-79-24, March 28, 1979.
6.
R. H. Groce (MYAPC) to R. W. Reid (NRC), MY Inservice Inspection and Testing Program, WMY-79-88, September 4, 1979.
7.
R. H. Groce (MYAPC) to R. W. Reid (NRC), submittal of additional copies of ISI and Testing Program, September 21, 1979.
3.
R.
A. Clark (NRC) to J.
H. Garrity (MYAPC), March 23, 1982.
9.
J. H. Garrity (MYAPC) to R. A. Clark (NRC), Inservice Inspection
~
Program - Additional Information, MN-82-87 (JGH-82-79), April 30, 1982.
10.
J.
B.
Randazza (MYAPC) to R.
A.
Clark (NRC), Modification to Maine Yankee Technical Specifications Concerning Inservice In-spection, MN-82-103, Proposed Change 67, Supplement 1, May 27, 1982.
11.
J.
H.
Garrity (MYAPC) to R.
A.
Clark (NRC), Revision 2 to Inservice Inspection and Testing Program, MN-82-199 (JHG 188), October 12, 1982.
12.
B. W. Johnson (SAI) to NRC, Final Technical Evaluation Report for Maine Yankee Nuclear Power Station, Report Number SAI-186-028-28, August 19, 1982.
13.
S.
R.
- Doctor, F.
L.
- Becker, G.
P.
Selby, Effectiveness and Reliability of Inservice Inspection, A Round Robin Test, pre-sented at the 5th International Conference on NDE in the Nuclear Industry, May 10-13, 1982, San Diego, CA.
28
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