ML20106A657
| ML20106A657 | |
| Person / Time | |
|---|---|
| Site: | Robinson  |
| Issue date: | 07/31/1984 |
| From: | SCIENCE APPLICATIONS INTERNATIONAL CORP. (FORMERLY |
| To: | NRC |
| Shared Package | |
| ML14192A561 | List: |
| References | |
| CON-NRC-03-82-096, CON-NRC-3-82-96 SAI-84-1650, NUDOCS 8410100494 | |
| Download: ML20106A657 (28) | |
Text
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SAI-84/1650 H. B. ROBINSON STEAM ELECTRIC PLANT UNIT 2 INSERVICE INSPECTION PROGRAM TECHNICAL EVALUATION REPORT Submitted to:
U. S. Nuclear Regulatory Commission Contract No. NRC-03-82-096 I
Science Applications, Inc.
Idaho Falls, ID 83401 1
l July 31, 1984 l
8421804% XA
CONTENTS INTRODUCTION...............................
1 I.
CLASS 1 COMPONENTS 3
i i
A.
Reactor Yessel 3
1.
Request for Relier No. 3, Circumferential Weld in the Closure Head, Category B-A, Item B1.21 3
B.
Pressurizer 4
1.
Request for Relief No.10 Nozzle Inner Radii, Category B-D, Ites 53.120.
4 C.
Heat Exchanger and Steas Generators 5
1.
Request for Relief No. 9, Nozzle to Vessel Welds Items B3.150.................., Category B-D, 5
2.
Request for Relief No.10, Nozzle Inner Radii, Category B-D, Items 83 140 and B3 160.
6 D.
Piping Pressure Boundary 8
1.
Request for Relier No. 2. Reactor Yessel Nozzle to Safe-End i
Welds, Category B-F, Iten B5.10 - Piping Safe-End Welds, Category B-F, Ites B5.50.
8 2.
Request for Relief No. 4. Pressure Retaining Welds id Piping, Category B-J, Items B9.10.and 89 31.
9 3.
Request for Relief No. 5, Pressure Retaining Welds in Piping, Category B-J, Ites 89.12.
10 4.
Request for Relief No. 8, Pressure Retaining Welds in Piping, Circumferential Butt Weld, Catsgory B-J, Items B9.11 and 59 12.
12 5.
Request for Relief No. 6. Miscellaneous Class 1 Piping Integrally Welded Attachments, Category B-K-1, Ites B10.10.
i 14 j
E.
Pump Pressure Boundary 15 1.
Request for Relief No.1, Pump Casing Welds, Category B-L-1, Item B12.10 15 l
l 2.
Request for Relief No. 7, Integral Attachments for Peps, j
Category B-K-1, B10.20 16 P.
Valve Pressure Boundary (no relief requests) 17 II.
CLASS 2 COMPONENTS 18 bv
CONTENTS (Cont'd) 18 A.
Pressure Yessels 1.
Request for Relief No.1, Pressure Retaining Welds in Pressure Vessels, Category C-A, Itea C1 30..............
18 2.
Request for Relief No. 2, Pressure Retaining Nozz'le Welds in RHR Heat Exchangers, Category C-B, Itea C2.20.
19 20 B.
Piping 1.
Request' for Relief No. 3, Pressure Retaining Welds in Piping, 20 Category C-F, Ites C5.21.
C.
Pumps (no relief requests) 20 D.
Valves (no relief requests)................... 20 III. CLASS 3 COMPONENTS (no relief requests) 20 IV. PRESSURE TESTS (no relief requests) 20 V. GENERAL
........................'...... 20 1.
Request for Relief No.15, Reactor Yessel and Pressurizer Calibration Blocks Material.
20 REFERENCES 22 O
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TECHNICAL EVALUATION REPORT lMSERYlCE_IMSPICIIQM_EROGRAM H. B. Robinson Steam Electric Plant Unit No. 2 INTRODUCTION This report evaluates requests for relief from Section XI of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Codes by the licensee, Carolina Power & Light Company (CPL), for the H. B. Robinson Steam i
Electric Plant, Unit No. 2.
The relief requests cover the second 120-month inspection interval starting March 7,1981.
The requests are based upon the 1977 Edition of Section XI, with addenda through the stunner of 1978, as specified in the applicable revision of 10 CFR 50.55a.
The rest of this introduction stanzarizes (a) the scope of this report, (b) the previous review of relief requests by Science Applications, Inc.
(SAI)
, and (c) the history of H. B. Robinson 2 since the earlier review (2-5),
The current revision to 10 CFR 50.55a requires that Inservice Inspection (ISI) programs be updated each 120 months to meet the requirements of newer editions of Section II.
Specifically,' each program is to meet the requirenents (to the extent practical) of the edition and addenda of the Code incorporated in the regulation by reference in paragraph (b) 12 months prior to the start of the current 120-month interval.
The regulation recognizes that the, requirements of the later editions and addenda of the Code might not be practicci to implement at facilities because of limitations of design, seemetry, and materials of construction of components and systems.
It, therefore, permits exceptions to impractical examination or testing requirements to be evaluated. Relief from these requirements can be granted, provided the haalth and safety of the public are not endangered, giving due consideration to the burden placed on the licensee if the requirments were imposed. This report only evaluates requests for relief dealing with inservice examinations of components and with system pressure tests.
Inservice test programs for ptaps and valves -(IST programs) are being evaluated separately.
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' Hereinafter referred to asSection XI or Code.
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l Finally,Section XI of the Code provides for certain components and systems to be exempted from its requirements.
In some instances, these exemptions are not acceptable to the Nuclear Regulatory Commission (NRC) or are only acceptable with restrictions.
As appropriate, these instances are also discussed in this report.
In its previous report dated September 30, 1962, SAI( } evaluated relief requests for H. B.
Robinson Unit 2 covering the second 120-month interval beginning March 7,1981. The previous evaluation was based on submittals from I)
II) the licensee dated August 5,1W7
, October 25, 1978
, March 22, 1982IN, and September 17, 1982('}. A Safety Evaluation Report (3) based on the submittals
~
was transmitted to the licensee. On January 18, 1983, CPL submitted a new ISI program for the second 120-month interval which superseded all previous transmittals. The relief requests contained in the January.18,1983, submittal were based upon the 1977 Edition of Section XI of the Code, with addenda thn:mgh the summer of 1978. The Code edition and inspection intervals were in accordance with the revision of 10 CFR 50.55a applicable at the time.
Additional information was required to evaluate the revised CPL ISI plan,
)
and a request for additional information was submitted to the licensee The licensee responded to the request by submitting a complete set of revised relief requests plus two new relief requests (5)
The relief requests contained in Reference 5 are evaluated in this report.
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l I.
CLASS 1 COMPONENTS A.
Reactor Yessel r
1.
Reauest for Relief No. 1. Ciren=cerential veld in the closure Head. Catamory B-A. Item B1.21 Code Reauirement Volumetric examination of circumferential head welds in accordance with IWB-2500-3 snall cover the accessible length (includes essentially 100% of the weld length) of all welds in the first inspection interval, and the accessible length of one weld in the successive 2nd, 3rd, and 4th inspection intervals.
Deferral of inspection of bottom head welds to the end of an interval is permissible.
Code Reliet Recuest Relief is requested from volumetric examinations of the peel segment to disc weld in the closure head.
i Pronosed Alternative Eramination
. Visual examination for leakage during leak testing after each refueling outage and during the hydrostatic test to be performed near the end of the 120-month interval.
Licensee's Basis for Raouestina Relief Accessibility for examination of this weld was not provided for in the original plant design, which occurred prior to the j
issuance of Section II inservice inspection requirements.
This weld is considered inaccessible for volumetric examination due to 4
physickl space constraints.
The peel segment to disc weld in the closure head is completely enclosed within the pattern of control rod drive mechanisms (CRDM) penetrations inside the shroud such I
that no portion of the veld is accessible to either surface or
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volumetric examination.
This weld is shown in drawing CPL-101, a
Weld No. 1.
Evaluation The closure head peel segment to disc weld is completely r
within the pattern of the CRDM penetrations. This configuration I
precludes the Code-specified volumetric examination from either the inside or outside surface of the closure head for the entire length of the weld with currently available equipment. The severely limited access also precludes alternate surface examination.
These limitations are typical of this generation and type of reactor vessel design.
I The Code specifies that the accessible length of one j
circumferential head weld is to be volumetrically examined in the I
second inspection interval.
Only one circumferential weld exists in the H. B. Robinson closure head, and it is inaccessible for volumetric or alternate surface examination over ita' entire length 1
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with pr sent-day equipment. The Code ccknowledges that accessibility may be limited with respect to volumetric examination of closure head circumferential welds, but the intent of the Code is clearly to encourage some volumetric examination of the welds.
Conclusions _and. Recommendations Based on the above evaluation, it is concluded that for the welds discussed above, the Code requirements are impractical. It is further concluded that the alternative examination discussed will provide the neoessary added assurance of structural reliability.
Therefore, the following is recommended: Relief should be granted from the volumetric examination of the peel segment to disc weld in the closure head for the second inspection interval with the i
following provision:
1 a.
The licensee should reevaluate available inspection methods before the end of the second interval-to determine if new inspection equipment has been developed that will permit partial volumetric examinations of the weld.
References References 2, 3, and 5.
B.
Pressurizer 1.
Recuest for Relief No.10. Nozzle Inner Radii. Category B-D. Item B"4.12 0 Code Reouirement The nozzle inside radius section of category B-D nozzles in the pressurizer must be examined volumetrically in accordanoe with IWB-2500-7 during each inspection interval.
Code Relief Raouest Relief is iequested from the voltanetric examiration requirements of the nozzle inner radii.
Pronosed Alternative Examination i
None.
I Licensee Basis for Reauestina Relief The pressurizer nozzles inner radius areas are inaccessible from the inside. The nozzles are integrally cast with the vessel beads. Radiation levels are extremely high in t' e pressurizer 1
a making entry impractical.
Based on the inaccessibil,ity and radiation levels, volumetric examination of the presstrizer nozzles inner radius section will not be attempted, l
Evaluation The licensee has stated that the inner radius areas of the pressuriser nozzles are inaccessible from the inside without 4
providing furth3r Gxp1Cnation Cr drEwing3 to illustrcta th3 retur3 or cause of the inaccessibility. The licensee has also stated that radiation levels in the pressurizer are extremely high and that entry is impractical.
However, the licensee has not indicated specifically what radiation exposure would result from activities associated with entry into the pressurizer for conducting inspections of the nozzle inner radius areas.
In addition, the licensee has not addressed the possibility of volumetrically examining the presstrizer nozzle inner radius sections from outside the pressurizer.
The practicality of conducting examination of the nozzle inner radius areas on the pressurizer was also evaluated by reviewing the inservice inspection relief requests for eight other Westinghouse plants, and none of the other plants has required relief from this examination.
Conclusions and Recornmendations Based on the above evaluation, it is concluded that the j
information supplied by the licensee is insufficient to grant unconditional relief from examination of the ir.ner radius area on the pressurizer nozzles.
Therefore, the following is roccamended:
Relief should not be granted.
Instead, the licensee should be required to reevaluate the e'xaminations. Should the licensee conclude that relief is required after reevaluation, a detailed relief request should be submitted clearly illustrating the impracticality of conducting the examinations.
jkferences i
Reference 5.
C.
Heat Exchanger and Steam Generators l
^
1.
Raouest for Relief No. G. Morrie to Vessel Welds. Catamory B-D.
Iten B1.150 Code Reauirement l
l All full pene tration nozzle-to-vessel welds (includes l
nozzle-to-vessel weld and adjacent areas of nozzle and vessel) on l
the primary side of heat exchangers must be voltmetrically enamed l
in accordance with IVB-2500-7 during each inspection interval.
Code Relief Reauest
{
Relief is requested from 100$ volumetric examination of the regenerative heat exchanger nozzle-to-vessel welds.
Proposed Alternative Examination The licensee proposes visual and surface.
Licensee's Basis for Reauestina Relief The geometric configuration of the weld surface prevents ultrasonic examinations from being performed to the extent required by IVB-2500-7.
Examinations will be performed to the extent 5
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prcotical from the pipe end nezzle curfacss cdjecant to the wsid.
Surface examination of the weld will be performed to supplement the volumetric examination.
These welds are shown on drawing CPL-106, Welds 13-18.
e Evaluation The joint configuration of the nozzle-to-vessel welds on the primary side of the regenerative heat exchanger is such that complete examinations of the nozzle-to-vessel welds in accordance j
with IVB-2500-7 cannot be accomplished with currently available UT equipment. 1he licensee has committed to perform 'UT examinations from the pipe and nozzle surfaces to the extent practical and to provide surface examinations of the nozzle-to-vessel welds. The supplemental surface examination will provide increased assurance of the structural reliability of the joint.
Conclusions and Recommendations Based on the above evaluation, it is concluded that for the welds discussed above, the Code requirements are impractical. It is further concluded that the alternative examination discussed will provide t*w necessary added assurance of structural reliability.
Therefore, the following is recommended:
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Relief should be granted from complete volmetric examination of regenerative heat exchanger nozzle welds in accordance with IWB-2500-7, provided that:
a.
Best effort volumetric examinations of the nozzle areas are conducted.
b.
Altermate surface 'and visual examinations are conducted as proposed.
l Referances References.2, 3, and 5.
2.
Raouest for Relief No. 10. Norrie Inner Radii. Catemory B-D.
Ita== E9.140 and B1.160 Code Beauirement 4
The nozzle inside radius section of category B-D nozzles in the steam generators and regenerative heat exchangers must be i
examined volumetrically in accordance with IWB-2500-7 during each inspection interval.
Code Relief Reauest Relief is requested from the volmetric examination requirements of the nozzle inner radii for the steam generater and regenerative heat exchangers, i
i Pronosed Alternate Examination I
None.
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Licensee Basis for Reauestina Relief i
The steam generator nozzles are integrally cast with the vessel heads.
The inner radius area is covered by weld deposited stainless steel cladding which is in an "as welded" condition.
j Additionally, radiation levels inside the primary channel head l
are in the range of 10 R/hr.
In view of the cast nozzle design, rough clad surface, and radiation levels, volumetric examinations in this area will not be attempted.
The regenerative heat exchanger is a vessel of all welded construction, rwndering the nozzle inaer radius section inaccessible from inside the vessel.
Therefore, the nozzle inner radius volumetric examination will not be attempted.
The configurations of these nozzles are different from that shown in Section II, Figure IWB-2500-7.
The possibility of performing volumetric examinations of these areas from the vessel outside surf ace has been evaluated as impractical due to the configuration.
I Evaluation The steam generator nozzles are integrally cast with the vessel heads and are covered by weld deposited stainless steel cladding in the "as-welded" condition. The radiation levels inside the primary channels are in the range of 10 R/hr. Presunably the surface of the weld deposited cladding would have to be smoothed to permit ultrasonic examination of the nozzle inner radius area.
The licensee implies that the radiation exposure to werkers during the smoothing and inspection would be excessive, that is, in the 10 R/hr field typical of the primary piping. The licensee also states that examination of the steam generator nozzles from the external surface was evaluated and determined to be impractical due to the configuration.
i The regenerative heat exchanger vessel is of all welded construction, and no access to the interior is provided so the j
nozzle inner radius sections cannot be examined from the inside i
surface. A drawing of the nossle configuration provided by the licensee shows that the inner nozzle radius is shadowed by two welds with respect to ultrasonic examination of the inner radius area. There appears to be no practical method for examining the i
regenerative heat exchanger inner radius area.
Conclusions and Recommandations Based on the above evaluation, it is concluded that for the welds discumstd above, the Code requirements are impractical. It i
is further concluded that the alternative examination discussed l
will provide the necessary added assts ance of structural reliability.
l Therefore, the following is recommended: Relief should be, granted i
from the volumetric examination of the steam generator nozzle inner radii with the following provision a.
The licensee should visually inspect the nozzle inner radii if it is necessary to enter the steam generator inlet and outlet plenues for maintenance or other inspection activities.
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References 4
Reference 5.
D.
Piping Pressure Boundary 1.
Recuent for Relief No. 2. Reactor Yessel Norrie-to-Safe-End helds Catemory bF. Item B5.10 - Pinins Safe-End Velds Category B-F.
Item 5.50 i
Code Recuirement Examinations are required for each safe-end weld in each loop and connecting branches of the reactor coolant system during each inspection interval in accordance with IWB-2500-8. For nominal pipe size less than 4 inches, surface-only examinations are required. For larger pipe, surface plus volumetric examinations are required.
Includes dissimilar metal welds between combinations of (a) carbon or low alloy steels to high alloy steels, (b) carbon or low alloy steels to high nickel alloys, and (c) high alloy steels to high nickel alloys.
Code Relief Reouest Relief is requested from surface examination of 1005 or the
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primary nozzle safe-end welds.
Examinations wi.11 be perfomed to the extent practical.
i Pronosed Alternative Erne $ nation None.
Licensee's Basis for Reauestina Relief The "sandplug" access provided frcui the floor cf the refueling cavity to the cutside of the primary nozzle safe-ends is insufficient to permit surface examination to be performed on 1005 of the safe-ends. Examinations vill be performed to the extent practical to the limits of the available access.
Evaluation Due to the physical limitations en access to these welds, it j
is impossible to perform the required surface examinations on 1005 of the welds.
The initial design of the "sandplug" access did l
not allow sufficient space to perform the required examinations.
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l The licensee has committed to perform the examinations to the extent practical to the limits of the available access. Based on evaluations of units with similar design, such examinations are likely to cover a substantial portion of the welds.
The primary j
nozzle safe-end welds will be examined volumetrically in accordance with the Code.
1 Conclusions and Recommendations Based on the above evaluation, it is concluded that for these welds, Code requirements are impractical.
Therefore, it is l
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recommended that re?ief from examination requirements for these welds be granted to the extent necessary due to inaccessibility.
It is further concluded that the required volumetric examination, in conjunction with partial surface examinations, will provide the necessary assurance of structural reliability.
The licensee should be required to report to NRC the fraction of the required surface examination actually completed.
References References 2, 3, 4, and 5.
2.
Reauest for Relief No. 4. Pressure Retainine Welds in Pining.
l Caterory B-J.
Items B9.10 and BQ.91 Code Reauirement For circumferential welds with nominal pipe size 4 inches and greater and branch pipe connections (greater than 2 inches),
surface plus volumetric examinations in accordance with IWB-2500-8, 9,10, and 11 shall be performed over essentially 1005 of the weld length during each inspection interval, and shall include the following:
s.
All terminal ends in each pipe or branch run connected to vessels.
b.
ill termin=1 ands and joints in each pipe or branch run connected to other ccaponents where the stress levels exceed l
l the following limits under loads associated with specific seismic events and operational conditions.
1 (1) primary plus secondary stress intensity range of 2.45" for ferritic steel and austenitic steel, and (2) Caulative usage factor U of 0.4.
c.
All dissiailar metal welds between combinations of:
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(a) carbon or low alloy steels to high alloy steels; (b) carbon or low alloy steels to high nickel alloys; and l
(c) high alloy steels to high nickel alloys.
d.
Additional piping welds so that the total equals 255 of the circumferential joints in the reactor coolant piping system.
l This total does not include welds excluded by DB-1220. These additional welds may be located in one loop (one loop is currently defined fe both PWR and BWR plants in the 19l7 edition).
For lungitudinal welds with nominal pipe size 4 inch.es and greater, surface plus volumetric examinations shall be performed for at least a pipe-diameter length, but not more than 12 inches (305 mm) of each longitudinal weld intersecting the circumferential welds are required to be examined.
The initially selected welds shall be reexamined during each inspection interval.
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Code Relief Reauest Relief is requested from the surface examination requirments for certain circumferential and longitudinal. pipe welds for pipe j
sizes greater than 4 inches and for certain branch pipe connection welds greater than 2 inches in diameter.
l Pronosed Alternative Examination Full volumetric examinations of the total weld area will be performed in lieu of the required volumetric examination of the inner 1/3 of the pipe volume plus. outer surface examination.
Licensee's Basis for Recuestina Relief The Robinson Unit No. 2 was designed and constructed prior to the formalization of ASME Section XI. Therefore, in many cases, the surface examination is not practicable. CP&L will attempt to meet Code requirments but when impractical to do so, will substitute the more stringent, full volumetric examination.
Evaluation The licensee conciders that at certain piping welds, surfaos examination is not practicable.
As an alternative examina tion, the licensee has committed to perform full volumetric examinations of the volume bounded by positions ACFEDB as in Figure IWB-2500-8.
This full volumetric examination is at least equivalent to (a) the required surf ace only or (b) surf ace examination between positions A and B plus volumetric,, examination of the volune bounded by positions CFED.
In accordance with IWA-224, it is appropriate to grant relief to perform this full volumetric examination on any B910 or B9 31 weld.- The licensee has agreed to report each deviation from the Code under this relief on a case-by-case basis.
Conclusions and Recommendations
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Based on.the above evaluation, it is concluded that the alternative examination proposed by the licensee is at least e.
equivalent to the Code requirm ents. Therefore, the following is recommended in accordance with IWA-2240:
)
i Relief should be granted from the surface examination requirements for B910 and B9 31 pipe welds provided that full volumetric examinations of the volume. bounded by positions ACFEDB in Figure IWB-2500-8 be performed and such deviations from the Code be reported to the Commission on a case-by-case basis.
Rafarances l
References 2, 3, 4, and 5.
p 3.
Reouest for Relier No. si. Pressure Retainin, velds in Pinina.
Catemory B-J. Item BO 12 Code Beauirement Surface and volumetric examinations shall be performed during each inspection interval in accordance with IWB-2500-8 and shall 10
include at least a pipe diameter length, but not more than 12 inches (305 mm) of each longitudinal weld intersecting the ciremferential l
welds required to be examined. The initially selected welds shall be reexamined during each inspection interval.
Code Relief Reauent Relief is requested from the volmetric examination requirements for the longitudinal welds in the 90 <!egree elbows in the crossover leg of the reactor coolant piping.
Pronosed Alternative Examination Visual examination during system pressure tests. The surface exam will be performed as required.
Licensee's Basis for Raouestine Relief The 90-degree elbows in the crossover leg of the reactor coolant system are fabricated in two halves from austenitic stainless steel castings welded tc6 ether by the electroslag process.
The structure of the material is such that ultrasonic examirations cannot be performed as required *by IWB-2500. These welds will be subject to surface examination and visual examiration during system pressure tests. The structure and nature of the electroslag weld in the cast austenitic 90-degree elbows is such that the material is opaque to ultrasonic transmissions utilizing currently available tcchniques. Radiography is the only other available technique for volumetric examination.
It is not possible to obtain Code l
acceptable radiographs with double wall " shots" on these cocporents which are approximately 38 inches in diameter, 3 1/2 inches wall thickness, containing a 2-inch thick splitter plate and having radiation levels of up -to 300 nr/ hour on contact.
These welds are shown on drawings CPL-107,10TA, and 107B; welds 7 thru 10 (including adjacent long seams).
Eyaluation For the longitudinal velds in the 90-degree elbows, the cast pieces are fabricated of austenitic stainless steel and a volumetric examination is impractical.
A surface examination and visual examination for evidence of leakage are practial and satisfactory for determining the condition of the weld.
Cenelusions and Recommendations Based on the above evaluation, it is concluded that for the welds discussed above, the Code requirements are impractical. It is further concluded that the alternative examination discussed above will provide the necessary added assurance of structural reliability. Therefore, the following is recommended:, Relief should be granted from the volumetric examiration of the identified welds with the following provisions:
a.
Surface examinations should be performed on each of the longitudinal welds in the 90-degree elbows.
11
b.
The prcposed visual cxaminatienn shculd be performed en the 90-degree elbows when leakage and hydrostatic tests are conducted in accordance with IWA-5000.
References I
References 2, 3, 4, and 5.
4.
Recuest for Relief No. 8. Pressure Retainine We'Ida in Pinina.
Circumferential Butt Weld. Catenorv B-J. Items BO.11 and BQ.12 Code Reauirement Surface and volumetric examinations of essentially 100% of circumferential welds shall be performed during each inspection interval in accordance with IWB-2500-8 and shall include the following:
a.
All terminal ends in' each pipe or branch run connected to vessels.
b.
All terminal ends and joints in each pipe or branch run connected to other components where the stress levels exceed the following limits under losds associated with specific seismic events and operational conditions:
(1) primary plus secondary stress intensity range of 2.4S, for ferritic steel and austenitic steel, and (2) cumulative usage factor U of 0.4.
4 c.
All dissimilar metal welds between combinations of:
j (a) carbon or low alloy steels to high alloy steels; (b) carbon or low alloy steels to high nickel alloys; and (c) high alloy steel to high nickel alloys.
d.
Additional piping welds so that the total equals 25% of the i
circumferential joints in the reactor coolant piping system.
This total does not include welds excluded by DiB-1220. These additional welds may be located in one loop (one loop is currently defined for both FWR and BWR plants in the 19T7 edition).
For longitudinal walds with nominal pipe size 4. inches and greater, surfeos plus volumetric examinations shall be performed for at least a pipe-diameter length, but not more than -
12 inches (305 mm) of each longitudinal weld intersecting the 4
circuaterential welds are required to be examined.
The initially selected welds shall be reexamined during each inspection interval.
Code Relief Reauest Relief is requested from the surface and volmetric examination requirments for one pressure retaining circunferential butt piping l
weld attaching the pipe to the 15-degree elbow in each reactor ooolant cold leg.
12
Prooosed Alternative Examination i
. None, except Code-required hydrostatic testing.
l Licensee's Basis for *feauestine Relief l
The circuaterential butt weld attaching the pipe to the 15-degree elbow in each reactor coolant cold les is completely enclosed within the biological shield and is not accessible for examination by either volumetric or surface techniques.
i These welds are shown on drawings CPL-107, 107A, and 107B, weld 13 Evaluation The identified welds are completely inaccessible for volumetric or surface examination because the welds are located within the biological shield. The initial design of the assemblies did not provide for accessibility for inservice examinations.
If it is assumed, though, that the workmanship and quality assurance of the welding as well as the preservice examinations were adequate, then an examination of the first pressure boundary weld outside the biological shield should reflect service induced failures for i
that particular piping section.
Thus, the first pressure boundary weld outside the biological shield on each of these process pipes should be volumetrically examined, where practical, over 1005 of its length during each inspection interval. Under a. of the Code Requirement, the licensee is already examining the next weld closer to the reactor vessel in each loop, -i.e.,
the weld between the other ord of the 15-degree elbow and the reactor vessel nozzle.
Also, the licensee could conduct visual examinations at the shield penetrations.
Conclusions and Recommendations Based on the above evaluation, it is concluded that for the welds discussed above, the Code requirements are impractical. It
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is further concluded that the alternative examination discussed above will provide necessary added assurance of structural reliability. Therefore, the following is recommended:
Relief should be granted from the surface and volumetric examination of the identified welds with the following provisions:
a.
The first pressure boundary veld outside the biological shield on each of these process pipes'should be volumetrically examined, where practical, over 1005 of its length during each inspection interval.
b.
Visual examinations should be performed at the shield penetrations when leakage and hydrostatic tests are conducted in accordance with 1WA-5000.
Refarancas References 2, 3, and 5.
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i 5.
Beauest for Relief No. 6. Miscellaneous class 1 Pinine Interrally Welded Attachments. Category B-K-1.
Item B10.10 i
Code Ranuirement Tolumetric or surface examinations, as applicable, per Figures IWB-2500-13,14, and 15, are required for all welded attachments of piping required to be examined by Examination Category B-J and the welded attachments of associated pumps and valves integral to such piping.
Only those attaehments whose base i
material design thickness is 5/8 inch or greater need to be examined.
j 4
Code Relief Reauest Relief is requested fran the volumetric examination requirements to the extent required by the Code for the' piping system integrally welded supports that are attached to the pipe by fillet welds.
Pronosed Alternative Examination 1rolumetric examination tect)niques will be used to examine the base material of the pipe wall and surface examination will be performed on integrally welded attachments.
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i Licensee's Basis for Reauestina Relief The piping system integrally welded supports ar e attached to the pipe by fillet welds.
The configuration of such welds is such j
that examinations cannot be performed to the extent required by IWB-2500, 'and only the base material of the pipe wall can be i
examined by ultrasonic techniques.
The postulated failure for a fillet weld attachment is that cracking would initiate at the toe of the weld and as such would be most readily detected by surfaos examination.
Evaluation In accordance with Figure IW2500-15, only surface examination is required for piping integrally welded supports attached by a fillet veld. Based on loading conditions of these types of welds, l
flaws would most likely generate at the veld surface and, thus, be detectable by surface examination.
Conclusions and Recommendations l
l Based on the abova evaluation, it is concluded that for the welds discussed above, no relief is required and should not be granted.
1 References
.w References 2, 3, and 5.
14
E.
Pump Pressure Boundary 1.
Recuent for Relief No.
1.
Punn Casinz Welds. Catexory B-L-1.
Item 612.10 1
Code Reauirement l
The volumetric and surface examinations perfomed during each inspection interval in accordance with IVB-2500-16 shall include 100% of the pressure-retaining welds in at least one pap in each group of pumps performing similar functions in system (e.g.,
recirculating coolant pumps). The examinations hay be performed at or near the end of the inspection interval.
'i Code Relief Raouest i
Relief is requested from surface examination of the casing welds in the reactor coolant pumps.
Volumetric examination will be performed.
Alternative Examination None.
Licensee's Basis for Recuestina Relief A reacte coolant pap casing is a welkent of four type 316 SS cast rings.
These castings do not lend themselves to surface examination due to the numbe'r of indications that would be present i
due to surface roughness.
Also, the time required to clean the surface for adequate surface examination and the inspection time would result in extracely high personnel exposures. To put this in the proper perspective, below are listed exposures received during insulation removal and replacement activities on B mactor coolant ptmp during the 1982 outage.
Insulation removal - 730 an Insulation replacement - 6.07 R l
These exposures are indicative af those that would be received during a surface examination.
Therefore, due to the above and the fact that volumetric examination will be performed, a surface examination is considered i
impractical for reactor coolant pumi, casing welds. These welds are shown on drawing CPL-144A; Welds A, B, and C.
Evaluation The castings from which the pump casing weldment is fabricated and the weld itself are not suitable for surface examination.
Preparation of the weld and casting surfaces to permit meaningful surface examination would result in significant radiation exposure and considerable cost without an offsetting increase in asstrance of structural reliability.
The Code-required full volumetric examination of the pump casing welds will be conducted.
15
Conclusions and Recommendations Based on the above evaluation, it is concluded that for the welds discussed above, the Code requirements are impractical. It is further concluded that the alternative examination discussed will provide the necessary added assurance of structural reliability.
Therefore, the following is recommended: Relief should be granted from surface examination of the pump casing welds, provided the Code-required full volumetric examination of the welds is conducted.
References References 2, 3, and 5.
2.
Reouest for Relief No. 7.
Integral Attachments for Pumos.
Category B-K-1. B10.20 Code Reauireeent Volumetric or surface examination of 100% of the weld, as applicable, per Figures IVB-2500-13,14, and 15 is required for all welded attachments of piping required to be examined by Examination Category B-J and the welded attachments associated with pumps and valves irtegr&1 to such piping.- Only those attachments whose base material design thickness is 5/8 inch or greater need to be examined.
Code Relief Reauest Relief is requested from the volumetric examination of the integrally welded supports of the reactor coolant p'.:mps.
Pronosed Alternative Fwamination l
A surface examination will be substituted in lieu of the required volumetric examination.
Licensee's Basis for Raouestina Relief i
The reactor coolant pap support members are fabricated frtai l
thick wall cast austenitic materials, and the weld and adjacent material cannot be examined as required by IWB-2500 utilizing ultrasonic techniques.
I Evaluation Ultrasonic examination of these welds is impractical becauu of the heavy well and cast material of the pump support. Surface examination of the pap supports is expected to gravide an adequate indication of any developing problems.
i Conclusions and Reec- :ndations I
Based on the above evaluation, it is concluded that for the l
welds discussed above, the Code requirements are impractiemi. It is further concluded that the alternative surface examination above will provide the necessary added assurance of structural l
l 16
reliability. Therefore, it is recommended that relier should be granted from the volumetric examination of the identified welds if surface examination is performed instead.
These supports are shown on drawing CPL-144 References References 2, 3, and 5.
F.
Valve Pressure Boundary No relief requests.
O O
~
O i
a l
l 17 l
II.
CLASS 2 COMPONENTS A.
Pressure Vessels 1.
Reauest for Relief No.1. Pressure Retainine Welds in Pressure Yessels. Category C-A.
Item C1.10 Code Requirement Volumetric examination of 100% of the weld length of the tubesheet-to-shell weld in accordance with IWC-2520-2 is required.
Code Relief Reauest Relief from volumetric examination requirments where support members provide geometrical interference.
Procesed Alternative Examination Volumetric and surface examinations will be perfomed to the extent practical unless support components can be removed to provide additional access. Surfaos aminations will be supplemented where 100% volumetric examinations are not performed.
i Licensee's Basis for Reauestina Relief The location of support members may prevent ultrasonic examinations being performed to the extent required by IWC-2500.
Examination will be perf ormed to the extent practical unless i
support ccmponents can be removed to provide additional access.
l Surface examination will be performed on those welds where 100%
of the weld and heat affected zone cannot be examined ultrasonically, i
l Evaluation In instances ubere the locations of pipe supports or hangers restrict the access for examination of welds to the extent required, examinations will be performed to the extent practical.
If the supports can be removed without unduly stressing the system, examinations will conform to the requirements of IWC-2500. Where restrictions exist and volumetric examination cannot be perfomed over 1005 of the weld and heat affected zone, surface examinations will be performed to supplement the volumetric examination.
l l
Conclusions and Recommendations l
l Based on the above evaluation, it is concluded that for the shell-to-tube-sheet welds of the regenerative exchanger, the Code j
requirements are impractical.
It is further concluded that the alternative examination discussed above will provide necessary added assurance of structural reliability. Therefore, it is recommended that relief be granted free the volumetric eammiration requirments of the identified welds provided best-effort volumetric and surface examinations are performed.
18
2.
Recuest for Relief No. 2. Pressure Retainina Norrie Welds in RHR Heat Exchanners. Category C-B.
Item C2.20 Code Recuirement Srface and volmetric examination of all nozzles over 1/2-inch thickness at terminal ends of piping runs shall be examined during each inspection interval in accordance with IWC-2520-4.
Code Relief Recuest Relief is requested fra the volmetric examination requirements of the nozzle-to-vessel welds of the residual heat removal (RHR) heat exchangers.
Prooosed Alternative Ermeination Visual examination for leakage during system hydrostatic tests.
Licensee's Basis for Raouestina Relief The nozzle-to-vessel welds "of the.RHR heat exchangers are covered by a reinforcement ring and are not accessible for examination as required by IWC-2500. The geometric conrigaration is such that alternative NDE methods cannot be substituted. The reinforcement ring covering the RHR heat exchanger nozzle-to-vessel welds contains "tell-tale" holes such that visual examinations can be performed for evidence of leakage.
Drawing CPL-204, Welds 3 and 4.
Evaluation The velds required to be examined are completely covered by a reinforcing ring that prevents a volumetric examination as required by the Code. The ring is welded to the shell and nozzle.
These welds' are apparently completely accessible for surface examination, and surface examinations should be conducted to provide the necessary assurance of structural reliability.
The visual examinations of the welds during periodic hydrostatic i
testing proposed by the licensee would provide additional assurance that an adequate level of safety will be maintained.
Conclusions and Recommendations Based on the above evaluation, it is concluded that for the welds discussed above, the Code requirements are impractial. It is further concluded that the alternative examinations discussed i
above will provide necessary added assurance of structural reliability. Therefore, the following is recommended:
Relief should be granted fra performing volumetrie examination of two nozzle-to-vessel welds among the MIR heat exchangers for each unit, provided that:
a.
Surface examination is performed on the reinforcement ring welds that make the nosale-to-vessel welds inscosesible.
19
b.
Ticual examination cf the walda for leakage in perfomed during periodic hydrostatic testing in accordance with IWC-5000.
References References 2, 3, 4, and 5.
B.
Piping 1.
Reauest for Relief No.
"4.
Pressure Retainine Welds in Pinina.
Caterory C-F.
Item C5.21 Except for item number, this relief request is the same as the request to perform full volumetric examinations of the total weld area for Class 1 pressure retaining welds in piping (see ID.2 of this report).
Therefore, the following is recommended in accordance with IWA-2240:
Relief should be granted from strface examination requirenents for Item C5.21 pipe welds provided that full volumetric examinations of the volume bounded by positions ACFEDB in Figure IWC-2520-7 are performed and deviations from the Code are reported to the Commission on a case-by-case basis.
C.
Pumps a
No relief requests D.
Valves No relief requests
]
III. CLASS 3 COMPONENTS No relief requests IV.
PRESSURE TESTS No relief requests Y.
GENERAL I
I 1.
Raouest for Relief No. 11. Reactor Yeasel and Pressurizer rm1 h ation Blocks Material Code Reauirement In accordance with IWA-2232 and Section V, Article 4, the material i
from which the basic calibration block is fabricated shall be one of the following:
(a) nozzle dropout from the oosponent; (b) a component prolongation; or l
(c) material of the same material specification, product form, l
and heat treatment as one of the materials being joined.
20
Code Relief Reauest Relief is requested to use SA-533 Grade B material in lieu of SA-302 Grade B, and SA-508 material in lieu of SA-336 for fabrication of reactor vessel calibration blocks and SA-533 Grade B in lieu of SA-302 Grade B in the pressurizer calibration blocks.
Proposed Alternative Examination Not applicable.
Licensee Basis for Recuestina Relief Because the required materials, SA-302 Grade B and SA-336, are not available, use of replacement materials is requested.
Based on chemical and physical properties, the materials SA-533 Grade B and SA-302 Grade B are considered essentially equivalent. This parity is also evident when the properties of SA-336 and SA-508 material are reviewed. The materials are considered to be acoustically equivalent thereby meeting the intent of Article 5 of Section V, ASME Code.
The materials used in the reactor vessel are as follows:
Closure Head - SA 302 Grade B Closure Head Flange - SA-336 Vessel Flange - SA-336 Yassel Nozzles - SA-336 Yessel Shell - SA-302 Grade B Vessel Bottcnn Head - SA-302 Grade B The material used in the pressurizer shell courses is SA-302 Grade B.
Evaluation Based on a review of the material properties of the as fabricated materials and the requested substitute materials, SA-533 Grade B and SA-302 Grade B are equivalent for the purpose of fabricating ultrasonic calibration blocks.
SA-508 and SA-336 are also acoustically equivalent j
materials for calibration blocks.
l Conclusions and Recommendations Based on the above evaluation, it is concluded that for the calibration hiosks discussed above, the Code requirements are impractical.
The alternative calibration blocks discussed above will provide the necessary assrance cf structural reliability. Therefore, the following is recommended: Relief should be granted to use SA-533 Grade B for calibration blocks in conjunction with examinations of components fabricated from SA-302, Grade B and SA-508 for calibration blocks in conjunction with examinations of oceponents fabricated from.SA-336.
The use of the specified materials will permit the examinations to be conducted with the necessary level of calibration.
References Reference 5.
21
i REPERENCES 1.
Science Applications, Inc., H. B. Robinson Stamm Electric Plant. Unit 2.
Innervice Inanection Franean. Technieml Evaluation Renort., SAI Report No. 186-028-01, Saptember 30, 1982.
2.
S.
R., Zimmerman (CPE) to 3. A. Varga (NRC), H. E. Robinson Steam Electric e
Plant Unit No. 2. AMME Section II r'a=nonant Tant Penseam, J,amary 18, 1983 3
S~.
A. Varga (NRC) to E. E. Utley (CPE) Transmittal of Safety Evaluation by the Office of Nuclame n==etor Ranulations Related to ama.==ta for sal ter from Inmarvice Inanection Ranuirements. August 31, 1983 4.
Telecopy, NRC to CPE, Request for Additional Inrcreation, Jamar 7 27,1981i.
5.
S. R. Zimmersau (CP&L) to 3. A. Yarga (NRC), Supplement to Inservice Inspection and Relief Requests, April 30, 19886.
6.
E. E. Utley (CPE) to R. W. Reid (NRC), H. B. Robinaan Stamm Elaetric Plant.
Unit No. 2. Tamervice Tnanaction and Testine Franean, August 5,1977.
7.
E. E. Utley (CPE) to A. Schwencer (NRC), H. B. Robinson Steam-Electric Plant. Unit No. 2. Innervice Inanection--Revised Pronram Submittal, October 25,1W8.
8.
P. W. Howe (CPE) to S. A. Yarga (NRC), H. B. anhin=. m+- Elaetric Plant.
Unit No. 2. Ynmarvice Ynanection and Tant Penspam, March 22, 1982.
9 Telecopi, D. Woods (CPE) to G. Requa (NRC), navised Tables 11 and 1B, September 17, 1982.
1 5
e 22
SUPPLEMENTARY COP 9 TENTS 1.
Page 4 Category B-D in the 1977-578 code specifically includes the nozzle inside radius section as an identified item to be examined on reactor vessel, pres-surizer, steam generator and heat exchanger nozzles. Although category B-D is entitled full penetration welds of nozzles in vessels, the requirement to examine the nozzle inside radius section has been interpreted as applying to all nozzles including those that are integrally cast. The intent of the code was clarified in the Winter 1980 addenda by the inclusion of Figure IWB-2500-7(d) (attached) which specifically addresses examination of the inside radius section of integrally cast nozzles. The examination is included under category B-D in the 1980 code which is still titled " full penetration welds of nozzles in vessels".
Even though the category B-D title identifies full penetration nozzle welds, the intent of the code has been interpreted to apply to the nozzle inner radius section of all nozzles.
2.
Page 5 The only additional information supplied by the licensee was a simplified drawing of the Pressurizer. This drawing provided little clarification beyond the drawing originally supplied in the plan. The evaluation included l
in the TER is valid based on the information available to the reviewer. Ad-ditional explanation by the licensee would be required before the TER could be revised.
3.
Page 6 See 1 above.
l 4.
Page 15 The examination requirements for pump casing welds included under category B-L-1
~
in the Sunner 1978 addenda (attached) include requirements for both volumetric and surface examination.
i Fig. IWB 2500 7(d)
SECTION XI-DIVISION I
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rga notate waft t ickness t
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EXAMINATION REGION' EXAMINATION VOLUME' Nonle inside corner seg on M.N-O-P NOTES:
(1) Enamination regions areident.f.ed for the purpose of d.Ne ent.at.ng the acceptance standards in iws 3512.
(2) Exam. nation volumes may be determ.ned either by d. rect measurements on the component er tur measurements based on sepgn drawings.
I WBO FIG. IWB 2500 7(d) N0ZZLE IN SHELL OR HEAD (Examination Zone in Nozzles Integrally Cast or Formed in Shell or Head) l 72.4
o.
p e
TABLE IWB 25001 (CONT'D)
EXAMINATION CATEGORIES EAus=Attoes caricony e L.t. s M PnE55unt atTA.= sac writos = PUMP cA5:=c5 Ano vAtyt soost5 B-L-2, S.M-2. PUMP CA5188GS Afeo VALVE 3000E5 Essent and Frequency of Esaminatsen i
Esaminataan 1st Defmal of Iteen Parts peguireinents Enamination Acceptance Inspection Successive Inspection inspectaen to leo.
Esamuned Feg. fee.
Alettled Standard laternal latmas, 2nd, 3rd, 4th End of laternal Ponies 4
982.30 Pump Casing weeds twe 250016 Volumetric twS-35 e AN weds',*
Same as for ist intmat Perademar and Surface St2 29 Pinno Casing laternal Memal. VT t laternal Same as for ist interval Poemesmer Surfaces Surface',8 Wasses ett se Vasse sedy weeds twS-2See IF Vsewnetric two-35:e As weeds'*
Same as for ist laterval Permessibee and Surface SIP.ee vehe Body. escesene 4 an.
Internal.
Visesas VT t Internes Same as for Ist interval Permestaba, nemmel Poe Saec Surfaces Swtace'*
l tt i
i i,
Is0TES:
til Esanessessus are uniesd to needs in at seest ene pump in eersi peso of punos perfernung skinner fisections in tour synesen; e s, recrcussesag feelent pungs.
(2) (sammasteen sney be perfonned en some punip or ess e selected for volumetric esamenselon of useds.
e tM Esamenselens are lemsted te one essve umiin each yeso of vaeves seat are of sie same remeruchenal design, eg. gode, Sste or check valve, manufacturing useind and that are pertemme savnlar funct ens en ser system, e 3. contaenment esetateen, system essepressure protectien.
tel inc udrs enunetelly 100% of used length.
a
- ss c urie er prepare.
i o
i i
-