ML20135D119

Safety Evaluation of First Ten Year Interval Inservice Inspection Program Plan for Illinois Power Co,Clinton Power Station

ML20135D119
Person / Time
Site:	Clinton
Issue date:	12/04/1996
From:	NRC (Affiliation Not Assigned)
To:
Shared Package
ML20135D106	List: ML20135D102 ML20135D119
References
NUDOCS 9612090251
Download: ML20135D119 (27)

Text

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. # cueu y UNITED STATES

, g j NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20656 0001

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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION OF THE FIRST TEN YEAR INTERVAL INSERVICE INSPECTION PROGRAM PLAN ILLINOIS POWER COMPANY CLINTON POWER STATION DOCKET NUMBER 50-461 1.0 INTRODUCi?Qti The Technical Specifications for Clinton Power Station state that the

] inservice inspection of the American Society of Mechanical Engineers (ASME)

Code Class 1, 2 and 3 compenents shall be performed in accordance with Section XI of the ASME Boiler end Pressure Vessel Code and applicable addenda as required by 10 CFR 50.55a(g), except where specific written relief has been granted by the Commission pursuant to 10 CFR 50.55a(g)(6)(1). Subparagraph 50.55a(a)(3) states that alternatives to the requirements of paragraph (g) may be used, when authorized by the NRC, if (1) the proposed alternatives would provide an acceptable level of quality and safety or (ii compliance with the specified requirements would result in hardship or unusua)l difficulty without a compensating increase in the level of quality and safety.

Pursuant to 10 CFR 50.55a(g)(4), ASME Code Class 1, 2 and 3 components (including supports) shall meet the requirements, except the design and access provisions and the pre-service examination requirements, set forth in the ASME Code,Section XI, " Rules for Inservice Inspection of Nuclear Power Plant Components," to the extent practical within the limitations of design, geometry and materials of construction of the components. The regulations require that inservice examination of components and system pressure tests conducted during the first ten-year interval and subsequent intervals comply with the requirements in the latest edition and addenda of Section XI of the ASME Code incorporated by reference ir. 10 CFR 50.55a(b) twelve months prior to the start of the 120-month interval, subject to the limitations and modifications listed therein. The applicable edition of Section XI of the ASME Code for the Clinton Power Station first 10-year inservice inspec' don (ISI) interval is the 1980 edition through winter 1981 addenda. The components (including supports) may meet the requirements set forth in subsequent editions and addenda of the ASME Code incorporated by reference in 10 CFR 50.55a(b) subject to the limitations and modifications listed therein and subject to Comission approval.

Pursu ut to 10 CFR 50.55a(g)(5), if the licensee determines that conformance with an examination requirement of Section XI of the ASME Code is not practical for its facility, infomation shall be submitted to the Commission in support of that determination and a request made for relief from the ASME Code requirement.

Enclosure 1 9612090251 961204 PDR G ADOCK 05000461 PDR

After evaluation of the detemination, pursuant to 10 CFR 50.55a(g)(6)(1), the Commission may grant relief and may impose alternative requirements that are detemined to be authorized by law, will not endanger life, property, or the common defense and security, and are otherwise in the public interest, giving due consideration to the burden upon the licensee that could result if the requirements were imposed. In a letter dated June 5, 1996, Illinois Power Company submitted to the NRC its first 10-year interval inservice inspection program plan requests for relief for the Clinton Power Station. Additional information was provided by the licensee in its lette- dated September 20, 1996.

2.0 EVALUATION AND CONCLVS10MS The staff, with technical assistance from its contractor, the Idaho National Engineering Laboratory (INEL), has evaluated the information provided by the licensee in support of its first 10-year interval inservice inspection program plan Requests for Relief for the Clinton Power Station.

Based on the information submitted, the staff adopts the contractor's conclusions and recommendations presented in the Technical Letter Report enclosed. The staff has reviewed the licensee's submittal and has concluded that for Relief Requests Nos. 4005, 4006 (in part), 4011, 4012, and 4013, that the requirements of the Code are impreactical and, in order to perform Code-required examinations, design modifications would be required which would impose a burden on the licensee. The licensee's propored alternative provides reasonable assurance of operational readiness of the subject system.

Therefore, relief is granted pursuant to 10 CFR 50.55a(g)(6)(1) for Relief Requests Nos. 4005, 4011, 4012, and 4013, as requested. For Request for Relief 4006, relief is granted pursuant to 10 CFR 50.55a(g)(6)(1 for those welds that have been previously examined and the actual coverage)noted in the submittal (i.e., Weld Nos. NIA, B, N28, C, D, E, F, G, N3A, C, N4A, B, C, D.

NSA, N6B, C, N9A, N10, and N16). This relief is authorized by law and will not endanger life or property or the common defense and security. For the remaining welds of Request for Relief 4006 (i.e., Weld Nos. N2A, H, J, K, N3B, D, NSB, N6A, and N98), it is inappropriate to grant relief prior to the welds-being examined. Therefore, for these welds, relief is denied. It is our understanding that these welds are scheduled for examination during the sixth refueling outage currently ongoing. The licensee should complete these nozzle examinations, and request relief, if necessary, for limited examination coverage.

The staff concluded that compliance Code requirements contained in Relief Requests Nos. 4007 and 4008, would result in hardship or unusual difficulty without a compensating increase in quality or safety in that the licensee's proposed alternative provides reasonable assurance of operational readiness of the subject systems. Therefore, the licensee's alternatives contained in Requests for Relief Nos. 4007 and 4008 are authorized pursuant to 10 CFR 50.55a(a)(3)(ii) as requested. ,

The licensee's request to use Table-2500, Examination Categories B-L-2 and B-M-2, Items 812.20 and 812.50 of the 1989 Edition and commitment to implementing the applicable requirements of the 1989 Edition of the Code for

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j Request for Relief No. 4009 is authorized pursuant to 10 CFR 50.55a(g)(4)(iv),

provided all related requirements are met.

For Request for Relief No. 4010, relief is denied. The Code and the Regulations require that the licensee perform the examinations on the RPV

shell welds. After these examinations are completed, if the licensee

determines that the Code and Regulatory requirements for the RPV shell weld 4

examinations cannot be completely satisfied, an alternative to the examination requirements should be submitted pursuant to 10 CFR 50.55a(g)(6)(ii)(A)(5).

Principal Contributor: T. McClellan, DE/ECGB Date: December 4, 1996 1

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TECHNICAL LETTER REPORT ON THE FIRST 10-YEAR INSERVICE INSPECTION INTERVAL REQUESTS FOR RELIEF EQB ILLIN0IS POWER COMPANY CLINTON POWER STATION DOCKET NO. 50-461

1.0 INTRODUCTION

By letter dated June 5,1996, the licensee, Illinois Power Company, submitted nine requests for relief for Clinton Power Station (CPS).

Relief Request 4008 was revised based on a telephone conference with the licensee on September 13, 1996, and resubmitted by letter dated September 20, 1996. The Idaho National Engineering Laboratory (INEL) staff has evaluated these requests in the following section.

2.0 EVALUATION The Code of record for the Clinton Power Station's first 10-year inservice inspection interval, which is scheduled to end in April 1997, is the 1980 edition through winter 1981 addenda of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code,Section XI. The information provided by the licensee in support of the requests for relief from Code requirements has been evaluated and the bases for disposition are documented below.

A. Reauest for Relief 4005. Examination Cateaory B-A. Item B1.40. Reactor Pressure Vessel Head-to-Flanae Weld

[gde Reauirement: Table IWB-2500-1, Examination Category B-A, Item Bl.40 requires 100% surface and volumetric examination of the Reactor Pressure Vessel (RPV) head-to-flange weld as defined by Figure IWB-2500-5.

Enclosure 2

Licensee's Code Relief Reauest: The licensee has requested relief from 100% volumetric examination of weld number CH-C-2 because the volume that can be examined is limited by the RPV head flange configuration / geometry.

Licensee's Basis for Reauestina Relief (as stated):

"A portion of the Code-required examination volume cannot be completed due to the RPV head flange configuration / geometry. Figures IA through IE identify the geometrical limitation presented by the RPV head flange with respect to the various ultra head-to-flange weld '.o date.ponic examination techniques performed on the

" Performance of ultrasonic examination of approximately 69.6% of the required examination volume provides reasonable assurance of the structural integrity of the entire weld. IP has performed ultrasonic examination (to the maximum extent feasible) on two-thirds (2/3) of the length of this weld based on examinations conducted during RF-2 and RF-4.

No unacceptable indications were found. The remaining one-third (1/3) of the weld length is scheduled to be examined during the next refueling outage (RF-6). IP estimates similar examination coverage (i.e.,

approximately 69.6% of the required examination volume). It should be noted that during initial plant construction, the entire weld was radiographed and the results were acceptable. The weld was also ultrasonically examined in accordance with the Preservice Inspection Plan, and the results of that examination were also acceptable.

"ASME Section V, Article 4, requires that the examination volume (weld and adjacent base material) be scanned by straight and angle beam, 45' and 60*, techniques. Article 4 of ASME Section V allows that the examination can be performed from one side of the weld. Due to the flange configuration, ultrasonic examination can only be performed from the head side of the weld. Due to the bend radius on the flange side and the thickness of the flange, and based on previous examination experience with this configuration, only the following examination volumes can be scanned for the techniques listed below (not taking beam spread into account):

'Not included in this report.

Techniaue  % of Examination Volume Examined O' L-Wave 6145%

45* P-Scan 61.5%

60* P-Scan 61.5%

45' T-Scan 85.6%

60* T-Scan 94%

Composite examination volume-69.6%

"As shown above, at least one technique (60* T-Scan) covers over 90% of the examination volume, based on previous experience. IP believes that the actual area examined using the 45' T-Scan technique was also over 90%, however, if any indication would have been present in the area identified as not examined, it would have been difficult to size. For this reason, the examiner identified 85.6% coverage. IP also believes that the actual area previously examined using the 60* T-Scan technique was close to 100%. Again, if any indication would have been present in the 6% volume identified as not examined, it would have been difficult to size. It should be noted, given that the 60* T-Scan technique covers 94%

of the examination volume, the ASME considers 90% coverage to be acceptable per Code Case N-460. Code Case N-460 has been incorporated into Regulatory Guide 1.147.

"The examination limitation imposed by the RPV head-to-flange configuration makes it impractical to perform a complete volumetric examination (90% or more) of the weld for at least some of the examination techniques identified above. Based on the above, however, the structural integrity of the weld can be sufficiently confirmed by completing (in RF-6) the same ultrasonic examination methods and coverage for the remaining length of the weld as done for the first two-thirds of the weld length. IP has thus concluded that completion of the weld examination in this manner provides an acceptable level of quality and safety." l Licensee's Proposed Alternative Examination (as stated):

" Illinois Power Company (IP) proposes to complete ultrasonic examination of this weld to the maximum extent feasible for the required examination volume."

Evaluation: The Code requires both surface and volumetric examination of the RPV head-to-flange weld. However, the weld's location with respect to the flange limits ultrasonic scanning and makes the volumetric examination impractical to perfom to the extent required by tLe Code.

To complete the Code-required examination, design modifications to allow 0

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access would be required. Imposition of this requirement would cause a considerable burden on the licensee.

A significant portion (69.6%) of the subject RPV head-to-flange weld was examined. IP has examined two-thirds of the length of this weld, with similar examination coverage, during two previous refueling outages; no unacceptable indications were found. In addition, the Code-required surface examination was performed (i.e., no relief was requested for surface examination).

The examinations performed should have detected any existing patterns of degradation. Therefore, reasonable assurance of structural integrity has been provided. Based on the impracticality of performing the volumetric examination to the extent required by the Code, it is recommended that relief be granted pursuant to 10 CFR 50.55a(g)(6)(1).

B. Reauest for Relief 4006. Examination Cateaory B-D. Item B3.90. RPV Nozzle-to-Vessel Welds Code Reauirement: Section XI, Table IWB-2500-1, Examination Category B-D, Item B3.90 requires 100% volumetric examination of the RPV nozzle-to-vessel weld and adjacent base material as defined by Figure IWB-2500-7(b). At least 25% but not more than 50% of the nozzles shall be examined by the end of the first period and the remainder by the end of the interval.

Licensee's Code Relief Reauest: The licensee requested relief from examining 100% of the Code-required volume of the following nozzle-to-vessel welds:

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l Estimated % of j Weld Number Description Volume Examined NIA, B Recirculation Outlet Nozzles 69  ;

N28, C, D, E, F, G Recirculation Inlet Nozzles 63  !

l N2A, H, J, K Recirculation Inlet Nozzles *

N3A, C Main Steam Nozzles 66 l N38, D Main Steam Nozzles

• N4A, B, C, D Feedwater Nozzles 66 l l NSA Core Spray Nozzles 66 l NSB Core Spray Nozzles

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N68, C RHR Coolant Injection Nozzles 66 i N6A RHR Coolant Injection Nozzles *

! N9A Jet Pump Instrument Nozzles 68 l N98 Jet Pump Instrument Nozzles *

. N10 CRD Return Nozzles 68

N16 Vibration Instrument Nozzles 66 i

• These examinations will be completed during the next refueling outage (RF-6). IP expects the volume examined for each weld to be between 60 and 70%.

l Licensee's Basis for Reauestino Relitf (as stated):

! "A portion of the Code-required examination volume cannot be completed i due to the,RPV nozzle configuration / geometry. Attached Figures IA through IE identify the limitations presented by a typical RPV nozzle

configuration / geometry for each examination technique employed at Clinton l Power Station (CPS).

l " Performance of ultrasonic examination of approximately 60-70 percent of i the required examination volume for each of the identified welds provides j reasonable assurance of the structural integrity of each entire weld. IP i performed ultrasonic examination on 20 of these welds (to the maximum

extent feasible) during two previous refueling outages (RF-2 and RF-4) and found no unacceptable indications. The remaining 9 welds are scheduled to be examined during the next refueling outage. IP estimates

similar examination coverage for each of the remaining welds (i.e.,

i approximately 60-70% of the required examination volume). It should be noted that during initial plant construction, all of these welds were radiographed and the results were acceptable. These welds were also j ultrasonically examined in accordance with the Preservice Inspection j Plan, and the results of those examinations were also acceptable.

! "ASME Section V, Article 4, requires that the examination volume (weld

and adjacent base material) be scanned by straight and angle beam, 45' i and 60*, techniques. Article 4 of ASME Section V allows that the

examination can be perfonned from one side of the weld. Due to the RPV j nozzle configuration, ultrasonic examination can only be performed from i

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the shell side. Due to the bend radius and thickness of the nozzle, and based on previous examination experience with this configuration, the ,

following examination volumes can be scanned for a typical nozzle using '

the techniques listed below (not taking bea'n spread into account):

i Technique  % of Examir.stion Volume Examined 0* L-Wave 50%

45* P-Scan 60%

1 60* P-Scan 72%

1 45* T-Scan 80%

60* T-Scan 88% <

Composite examination volume - 70%

"As shown above, at least one technique (60* T-Scan) covers close to 90%

of the examination volume. IP believes that the actual area examined

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using the 45' T-Scan and 60* T-Scan techniques was over 90%, however, if any indication would have been present in the area identified as not examined, it would have been difficult to size. For this reason, the

examiner identified 80% and 88% coverage for the 45* T-Scan and 60*

T-Scan techniques respectively. It should be noted that the ASME, per

Code Case N-460, considers 90% coverage as meeting the Code requirements.

Code Case N-460 has been incorporated into Regulatory Guide 1.147.

j "The examination limitation imposed by the RPV nozzle /shell configuration t

makes it impractical to perform a complete volumetric examination (90% or more) of the nozzle-to-shell welds. However, IP believes that performance of ultrasonic examination of the welds to the maximum extent feasible (for a composite examination volume of approximately 70%) is sufficient for confirming weld integrity and that such examination therefore provides an acceptable level of quality and safety."

Licensee's Proposed Alternative Examination (as stated):

" Illinois Power Company (IP) proposes to perform ultrasonic examination of these welds to the maximum extent feasible for the required examination volume."

Evaluation: The Code requires that all RPV nozzle-to-vessel welds receive a volumetric examination as defined by figure IWB-2500-7(b) each inspection interval. However, the nozzle configuration / geometry restricts scanning, which limits the extent of the volumetric l examination.

The limitations illustrated in the drawings submitted with this relief ,  !

request support the licensee's determination that volumetric examination of the subject nozzle-to-vessel welds to the extent required by the Code  !

is impractical. To increase examination coverage, the subject nozzle-to-

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! vessel welds would require extensive design modification. Imposition of this requirement on Illinois Power Company would cause a considerable burden.

1 The licensee stated that the volumetric examination of each of these welds exceeds 60% cumulative coverage. This is a significant percentage,

! and it is reasonable to conclude that degradation, if present, would be

! detected. Consequently, reasonable assurance of the continued structural ,

{ integrity of the RPV is provided. Based on the information provided by j- the licensee, and the extent of the examinations that were performed, it is concluded that the volumetric examination of the subject nozzle-to-l vessel welds is impractical to perform to the extent required by the

! Code. Therefore, pursuant to 10 CFR 50.55a(g)(6)(i), it is recommended

that relief be granted for those welds that have been completed.

i j However, for the nozzle examinations not yet performed, it is inappropriate to grant relief prior to the welds being examined, j therefore, it is recommended that relief be denied. The licensee should -

l complete these nozzle examinations, 'and at that time, request relief, if l necessary, for limited examination coverage.

l C. Reauest for Relief 4007. Examination Cateaory B-J. Item B9.11. Feedwater j System. Pine-to-Valve Weld, I Code Reauirement: Section XI, Table IWB-2500-1, Examination Category

! B-J, Item B9.ll, requires volumetric and surface examination of the weld  !

and adjacent base metal as defined by Figuri IWB-2500-8.

Licensee's Code Relief Reauest: The licensee requested relief from  ;

selecting weld 1-FW-2-5 for performance of surface and volumetric

! examinations during the first 10-year interval.

l Licensee's Basis for Reauestina Relief (as stated):

1 "The subject weld is a pipe-to-valve weld on one of the two, main 18-inch l

feedwater lines inside the drywell. The associated feedwater pipe (the j

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! "B" line) is supported by a large component support (guide support) that  !

l supports the pipe at the weld location. A drawi  !

j complicatedguidesupportisattached(Figure 1)pgofthislargeand

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"In order to perfom the Code-required examination, guide support

! IFW01014G would have to be disassembled to gain access to this weld.

l Removal and reassembly of the guide support is a tedious process. For i

example, a temporary support would have to be installed prior to removing  !

, the guide support from the piping. Also, some of the replacement parts i that may be required, such as the associated Lubron plates, are not l readily available. Based on previous experience at Clinton Power Station j (CPS), i.e., during RF-2 when the sister guide support (for the "A" i feedwater line) was removed for examination of weld 1-FW-1-5, hundreds of i man-hours and several man-res of exposure must be expended to disassemble  !

j and reassemble the guide support. Finally, notwithstanding the cost and l

. effort, IP believes it is imprudent to dissemble this properly  ;

functioning guide support in light of IP's conclusion that a sufficient l number of welds have been examined (or are scheduled to be examined during the next refueling outage) as further discussed below.

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! "The reason for selecting weld 1-FW-2-5 for examination is that, based on l l the associated system stress report, this weld is subject to stress that j i

i exceeds the stress criteria identified in Note 1(b) of Table IWB-2500-1

! for Category B-J. However, there are two more Feedwater system welds

! subject to stress levels that exceed the Note 1(b) stress criteria, and i which are in the same Feedwater loop ("B") as the subject weld. These

two welds,1-FW-2-3-8 and 1-FW-2-3-9, are scheduled for examination in i the next outage. In addition, there are three welds in Feedwater loop 1

"A" at similar locations, for which applied stresses also exceed the Note i 1(b) stress criteria. All of those welds, 1-FW-1-5 (mentioned previously),1-FW-1-3-8 and 1-FW-1-3-9, have been examined, and the results were acceptable. Thus, by the conclusion of the next outage, i five of the six welds to which Note 1(b) applies will have been examined.

l (The relative locations of these welds in the feedwater piping is shown 1 on the attached isometric drawings, i.e., Figures 1 and 2 for feedwater

loop "A", and Figures 2 and 3 for feedwater loop "B".) In addition, for .

all welds required to be examined in the feedwater system (loops "A" and  !

i "B"), approximately 27% of all applicable welds have been examined in the i last five (5) outages, relative to the Code requirement of 25% over the

! ten-year interval. These welds were found to have no unacceptable

! indications. Based upon these examinations, IP believes the intent of the Code requirements for verifying the structural integrity of the feedwater system has been met. On that basis, selecting another weld in the feedwater system for examination instead of weld 1-FW-2-5 will still provide an acceptable level of quality or safety for the feedwater j system."

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Licensee's Proposed Alternative Examination (as stated)

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" Illinois Power Company (IP) proposes, in lieu of selecting this weld for examination, selecting a different weld in the Feedwater system for

examination."

i Evaluation: Note 1(b) of Table IWB-2500-1, Category B-J states that all

. terminal ends in each pipe or branch run connected to other components where the stress levels exceed the limits listed are to be examined. The l licensee has proposed to examine a different weld in the Feedwater system j in lieu of pipe-to-valve weld 1-FW-2-5. Access to the subject weld is j restricted by a large component support (IFW01014G). To perform the Code-required examination, the component support would have to be l disassembled, which would cause a considerable hardship.

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The licensee disassembled the " sister" component support in feedwater line "A" during refueling outage RF-2. Removal and reassembly of the component support required hundreds of man-hours and several man-rem of I

exposure, and some replacement parts were not readily available.

l There are six welds in feedwater loops "A" and "B" with calculated stresses that exceed the stress criteria identified in Note 1(b) of Table ,

IWB-2500-1 for Category B-J. Of the six welds, five will be examined by  ;

i the end of the interval. The three welds examined in Feedwater loop "A",  !

at similar locations, were found acceptable. The two welds in Feedwater loop "B"' will be examined by the end of the interval. In addition, the f

licensee has proposed to select an additional weld in the Feedwater i system for examination. Because the subject weld experiences similar

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applied stresses to components that have received the required i examinations, it is reasonable to conclude that structural integrity of j the subject system is maintained, i

! Based on the licensee's proposal to select an additional weld for

! examination, the extent of examinations performed, and considering the burden on the licensee if required to disassemble the subject component l

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' upport, it is recommended that the proposed alternative be authorized

,,ursuant to 10 CFR 50.55a(a)(3)(ii).

D. Reauest for Relief 4008 (revised). Examination Cateaory B-K-1. Items B10.10 and B10.20. Class 1 Intearal Attachments for Pioina and Pi=ns Code Reautrement: Section XI, Table IWB-2500-1, Examination Category B-K-1, items B10.10 and B10.10 requ\re 100% surfsee or voTumetr\c examination of integral attachment welds each inspection interval.

Lis;ysee's Code Relief Reauest: The licensee requested relief, for Item B10.10, from perfonning a complete Code-required surface examination of piping attachments / legs for weld numbers 1-MS-A-7PR-WA, 1-MS-B-8-PR-WA, 1-MS-C-8-PR-WA and 1-MS-D-7-PR-WA (for Main Steam systra (MS) guide supports), and IRR-A-PR-1-WA [for Reactor Recirculation system (RR) l variable support). Relief is also requested from performing the Code-  !

required surface examination on the pump attachments / lugs where the welds for shock suppressor lugs attach to the Reactor Recirculation Pump B bowl. The integral attachment number and estimated percent of area examined are listed in the following table.

Estimated Percentage Weld Number System Description of Area Examined IMS-A-7PR-WA Main Steam 25 IMS-B-8PR-WA Main Steam

• IMS-C-8PR-WA Main Steam 27 IMS-D-7PR-WA Main Steam 27 1RR-A-PR-1-WA Reactor Recirculation 65

• This item is scheduled for examination during the next refueling outage. IP expects the area examined to be 25 to 27 percent.

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e Licensee's Basis for Reauestina Relief (as stated):

i "For Item B10.10: Performing the required surface examination of the entire examination area for each of the welds associated with integrL1 attachments or lugs on each of the main steam lines and on the RR Loop "A" suction line requires the removal / disassembly of four guide supports (one for each steam line) and one variable support (for the RR loop "A"

' suction line) in order to gain access to the required examination areas.

For Item B10.20: In order to perform the required surface examination of the shock suppressor lugs on Reactor Recirculation Pump B the entire insulation surrounding the pump bowl, which is located in a high 1

radiation area, woulu have to be removed.

"For Item B10.10 - Main steam line attachments: Based on the size, design and installation of the Main Steam guide supports, disassembly and i

reassembly of these guide supports (one for each steam line) would be a

complicated and tedious process, involving a difficult procedure to implement. (A drawing attached as Figure 1.)'ofFurther, one of the Main Steam although none ofline the guide guide supports supports is were removed for any of the attachment weld examinations performed to date for the main steam lines, based on the previous disassembly of a similar guide support in another system, Illinois Power Company (IP) believes that completion of the process would require replacing the

Lubron plates for the supports, which are difficult to procure. The intent of the ASME Section XI examination is to provide assurance of structural integrity rather than require disassembly and reassembly of 1 properly functioning components / supports, possibly adversely affecting a their operability. Disassembly of a properly functioning guide support is thus not judged to be prudent. In addition, due to the extensive effort required, disassembly and reassembly of the main steam line guide supports would likely extend the duration of the outage and result in unnecessary radiation exposure.

"For Item B10.10 - Reactor recirculation piping attachment: The variable

, support for the associated Reactor Recirculation system pipe is a load-l carrying support. In order to remove this support, a temporary support would be required to be installed. The variable support is located 13 feet above the floor elevation and is in a high radiation area. Several man-hours would have to be expended to erect scaffolding, remove insulation, install a temporary support and transfer the piping load prior to removing the variable support. Further effort would then be required for system restoration. The total dose that would be incurred is estimated to be five (5) man-rem. Examining 65 percent of the weld area (to facilitate examination of the obstructed weld area for the attachment / lug on the associated recirculation line) should be sufficient to establish the integrity of the lug weld without significantly reducing the safety margin provided by such verification.

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l "For Item B10.20 - Shock suppressor lugs on RR Pump B: IP has performed examination of all the welded attachments on RR Pump A (which is

, essentially identical to RR Pump B). This is equivalent to 50% of the i total number of welded attachments on both RR pumps (A and B). In order i to perform the required surface examination of the shock suppressor lugs l on RR Pump B the entire insulation surrounding the pump bowl would have to be removed and reinstalled after the examination. The total dose that j would be incurred to perform this activity is estimated to be 3 man-rem.

Examining all of the welded attachments on RR Pump A, or 50% of the total

number of attachment welds on both RR Pumps, will reduce the undue burden l on IP (i.e., the cost in resources and man-res) but stil.1 support the

safety margin provided by adequate verification and assurance of weld integrity for the RR pump shock suppressor lugs." i Licensee's Prooosed Alternative Examination (as stated)

"For Item B10.10: Perform a surface examination of each of the weld areas to the maximum extent feasible without removal or disassembly of the associated component supports. Table 1 identifies the examination coverage feasible based on examinations that have been completed to date and on what is projected to be done for the remaining weldr to be examined in the next scheduled refueling outage. For Item B10.20: l Perform a surface examination of at least 50% of the total number of '

shock suppressor lug welds for RR pump A and B." ,

Evaluation: The Code requires 100% surface examination of all integral attachments associated with Class I pumps and Examination Category B-J piping systems. The licensee is proposing to perform a surface l examination to the maximum extent feasible, without removing or disassembling associated component supports, for the five subject piping (Itse B10.10) integral attachments. For ti.:: reacter recirculation pump shock suppressor lugs (Item B10.20), the licensee is proposing to perform the Code-required surface examination on 50% of the RR pump integral attachment welds. These proposals will be addressed individually below.

For Item B10.10, in order to perform the Code-required surface examination on the main steam integral attachment welds, the main steam guide supports would have to be disassembled, removed, and reassembled.

This process is difficult, requires many man-hours, and results in significant radiation exposure; in addition, replacement parts are difficult to procure. Examining the integral attachment weld on the reactor recirculation piping would require that a variable support be disassembled, removed, and reassembled after the installation of a

i l

I temporary support. All of this effort would take place in an environment )

{ that would result in personnel radiation exposure (estimated to be 5 man-  !

I res). Performance of these examinations would place a significant burden f

on the licensee.

The licensee is currently selecting 100% of the Class 1 integral j attachment welds in Category B-J piping for examination. CPS is unable to perform a complete surface examination on the five subject integral attachment welds. However, since these five integral attachments are a i small fraction of the overall population of integral attachment welds l receiving the Code-required surface examination, and the subject welds

) receive a partial surface examination, reasonable assurance of structural i integrity is provided.

! l j For Item B10.20, the entire insulation surrounding the pump bowl would have to be removed to complete the Code-required examination. The j process would require many hours in a high radiation area and result in j excessive personnel radiation exposure. This would cause a considerable

! burden on the licensee. All of the Reactor Recirculation pump shock j suppressor lugs on Pump "A" have been examined. Thus, the licensee's l alternative to examine all of the lugs on one of the two pumps is

) equivalent to a 50% sample. Because both pumps see similar stresses, and l because of the significant number of lugs examined, reasonable assurance j of structural integrity is provided.

i It is concluded that compliance with the Code requirements would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety. Based on the extent of integral attachment welds being examined, reasonable assurance of operational readiness is provided; therefore, it is recomended that relief be authorized pursuant to 10 CFR 50.55a(a)(3)(ii).

i

E. Reauest for Relief 4009. Examination Cateaories B-L-2 and B-M-2.

l Ita= B12.20 and B12.50. Class 1 Pu=a Casina and Valve Body Internal j Surfaces i

! Code Reauirement: Section XI, Table IWB-2500-1, Examination Categories B-L-2 and B-M-2, Items B12.20 and B12.50 require visual (VT-3) l

! examination of pump casing and valve body internal surfaces during each l inspection interval. Examinations are limited to one valve within each

' group of valves that are of the same structural design and manufacturing method and that perform similar functions in the system.

! Licensee's Code Relief Reauest: The licensee requested relief from

! performing the Code-required visual (VT-3) examination of pump and valve internal surfaces on the following:

l 1

i Reactor Recirculatfon Pumps: "A" (IB33-C001A) or "B" (IB33-C001B);

Falves: IB21-F-Olla, IB33-F023A, IB33-F060A, IB33-F067A, IE12-F008, IE12-F010, IE12-F039A, IE12-F041A, IE21-007, IE22-F036, AND IG33-F102.

Licensee's Basis for Reauestina Relief (as stated):

"In order to perform the required visual (VT-3) examinations, Clinton Power Station personnel would have to disassemble the affected components. Hundreds of man-hours and several man-rem of exposure would be expended for the erection / dismantling of scaffolding, removal / reinstallation of insulation, and disassembly / reassembly of the pump and valves only to perform these VT-3 examinations. Illinois Power Company (IP) has determined that the hardship involved in performing the VT-3 examinations is unwarranted and that it is imprudent to disassemble properly functioning pumps or valves just for the sake of such examinations.

"It is imprudent to disassemble properly functioning pumps or valves only to perfors VT-3 visual examinations of internal surfaces, nor is it good ALARA practice to incur exposure of several man-res only for such examinations. The 1989 Edition of ASME Section XI reflects a change to the requirements for VT-3 examinations such that VT-3 internal surface examinations of pumps and valves are only required when pumps and valves are being disassembled for maintenance. It would be an unnecessary burden on Illinois Power to dissemble / reassemble the identified pump and valves solely to comply with the 1980 Edition (through Winter 1981 Addenda) of ASME Section XI in light of the fact that the NRC has l

incorporated a newer (1989) Edition into 10CFR50.55a(b) which only requires the VT-3 visual examinations to be performed when the pumps or valves are being disassembled for maintenance. Revision of the Code and its acceptance by the NRC and the industry confirm that performance of VT-3 examinations during puup or valve disassembly for maintenance is sufficient for examining internal surfaces for component integrity I relative to disassembling components just to perform such examinations.

Considering the potential effects of unnecessary disassembly and the radiation exposure involved in performing such work and in performing the VT-3 examinations themselves on a periodic basis, there does not appear to be any overall safety benefit to be gained by performing VT-3 examinations in accordance with the Edition of the Code to which IP is g currently committed (for the first ten-year interval)."

O Licensee's Proposed Alternative Examination (as stated):

"In lieu of the requirements of ASME Section XI,1980 Edition through Winter 1981 Addenda, for Categories B-L-2 and B-M-2, IP proposes to utilize ASME Section XI, 1989 Edition, which has been incorporated into 10CFR50.55a(b)."

Evaluation: Visual examination of pump and valve internal surfaces is performed to determine if unanticipated degradation of the pump casing or valve body is occurring due to phenomena such as erosion, corrosion, or cracking. To perform this examination, complete disassembly of the component is necessary. Thus, the Code-required visual examinations involve a major effort, requiring many man-hours by skilled maintenance and inspection personnel, who undergo significant radiation exposure.

Therefore, disassembly of pumps and valves for the sole purpose of performing the Code-required visual examination presents a significant hardship. ,

The licensee's alternative is to incorporate the 1989 Edition of Section XI for Categories B-L-2 and B-M-2, which has eliminated disassembly of pumps and valves for the sole purpose of examining the internal surfaces and states that the internal surface VT-3 visual examination is only required when pumps or valves are disassembled for maintenance, repair, or volumetric examination.

The 1989 Edition has been soproved for generic use by incorporation into the Regulations. In the licensee's submittal dated June 5,1996,

I Illinois Power committed to implementing the applicable requirements of the 1989 Edition of the Code for this relief request. Therefore, pursuant to 10 CFR 50.55a(g)(4)(iv), it is recommended that the requirements of Table IWB-2500-1, Categories B-L-2 and B-M-2, Items B12.20 and 812.50 of the 1989 Edition with associated requirements, be authorized as an acceptable alternative for the subject examinations.

F. Reauest for Relief 4010. Examination Cateaory B-A. Items Bl.11 and Bl.12.

Reactor Pressure Vessel Circumferential and Lonaitudinal Shell Welds Code Reauirement: Section XI, Table IWB-2500-1, Examination Category B-A, Items B1.11 and 81.12 require 100% volumetric examination of all reactor pressure vessel (RPV) circumferential and longitudinal shell welds during the first inspection interval as defined by Figures IWB-2500-1 and IWB-2500-2.

Licensee's Code Relief Reauest: The licensee requested relief from the Code-required volumetric examination of RPV.circumferential welds RPV-C1 and RPV-C2 and longitudinal welds RPV-VIA, RPV-VlB, RPV-V2A, RPV-V2B, and RPV-V2C.

Licensee's Basis for Reauestina Relief (as stated): l "The subject welds are located behind the biological shield wall (surrounding the RPV) where the radiation levels are extremely high.

Even after nozzle flushing, Illinois Power Company (IP) estimates a personnel exposure of 20 man-rem to perform the required inspections. In addition, IP estimates the cost of performing examinations of these welds to be approximately $400,000.

"On September 28, 1995, the BWR Vessel and Internals Project (BWRVIP) submitted a topical report to the NRC, entitled "BWR Vessel and Internals Project, BWR Reactor Vessel Shell Weld Inspection Recommendations (BWRVIP-05)", EPRI TR-105697, which recommends alternative examination criteria for Category B-A, Item Bl.11 and Bl.12 welds. The conclusions and recommendations in this report are consistent with IP's request for relief to reduce the scope of required examinations for the applicable  !

welds.

"Clinton Power Station (CPS) has four (4) circumferential welds per Item No. Bl.11 (RPV-Cl through RPV-C4) and 11 vertical welds per Item No.

i e

Bl.12 (RPV-VIA through RPV-V4C). During plant construction, as required by ASME Section III, all of these welds were examined by surface and radiographic examination methods, and accepted as free of any manufacturing f;aws. As part of the Preservice Examination Plan, CPS also performed ultrasonic examination on these welds, and they were accepted for placing the RPV in service. Further, a hydrostatic test at over 1500 psi was satisfactorily performed in accordance with ASME ,

Section III requirements. With respect to assembly of the RPV itself, '

the vessel was built under rigorous requirements for fabrication and examination, and post-weld heat treatment during fabrication assured that shell weld and cladding residual stresses were minimized. These controls and actions, along with all of the above-noted surface, radiographic, and ultrasonic examinations, greatly reduced the likelihood of large flaws existing in the shell weld, especially at the vessel surfaces, and thus contributed to providing assurance of RPV integrity.

"During the first ten-year inspection interval (i.e., during refueling outages RF-2 and RF-4), the following welds were ultrasonically examined and accepted for continued operation:

Cire. Welds per Item No. Bl.11 Vertical Welds ner Item No. Bl.12 RPV-C3 RPV-V3A, V3B, V3C RPV-C4 RPV-t'4A, V48, V4C "The above welds comprise 50% of the circumferential welds for Item Bl.11 and almost 55% of the vertical welds for Item Bl.12. The examinations performed for these welds (as well as the ultrasonic examinations performed as part of Preservice Inspection Plan) were performed in accordance with Reg Guide 1.150. In addition, other welds or portions of other welds on the RPV were examined by ultrasonic method during RF-2 and RF-4 and accepted for continued service. These include 50% of the shell-to-flange weld, over 60% of the top-head-to-flange weld, some top-head welds, portions of the bottom-head-to-support-skirt weld, and several nozzle-to-shell welds.

"A combination of BWR operating characteristics and good material properties makes CPS inherently flaw tolerant during operation. The i operating characteristics of a BWR like CPS preclude extreme brittle I fracture combinations of pressure and temperrture (due to saturated conditions for operating BWRs), such that the periodic RPV pressure test is the most limiting condition. These favorable operating characteristics are acknowledged in EPRI TR-105697. Further, the EPRI l report discusses.a survey of vessel inspection information that was  !

conducted for BWRs. The following results were reported:  !

"For the 24 BWRs included in the survey, a cumulative total RPV weld length of 14,565 ft is currently required to be examined.

Of the total 14,565 ft of weld, 4770 ft has undergone full Code examination. Another 487 ft of weld has undergone partial Code 1 4

I ,

.. l l 4 examination. The total length of weld examined to date i therefore equals 5257 ft, or 36% of the total possible weld length. In 5257 ft of weld examined to date, only 16 indications were found that did not meet the acceptance

, criteria of ASME Section XI, IWB-3500. All 16 of those j indications were subsurface flaws that were shown to be ,

d acceptable by meeting the criteria of IWB-3600.  !

! "It is clear from the survey results that a substantial amount of examination has been perforised to verify the integrity of BWR Vessels, j l and that only a negligible number of indications have been detected as a i t' . result. Per EPRI TR-105697, it has been concluded that the Code-required volumetric inspection scope for BWR RPV shell welds (Category B-A, Item  :

Bl.Il & Bl.12) during each ten-year interval may be replaced with the

following volumetric inspection requirements, without a significant j impact on BWR integrity:

i "1. Inspect 50% of longitudinal seam welds (Category B-A, Item No Bl.12) in the reactor vessel shell. This requirement may be ,

satisfied by inspecting 50% of the total weld length of this '

i category of weld, using any combination of the total number of 3

welds or percentage of each weld inspected to achieve this 1 overall percentage.

J "2. Inspect 0% of the circumferential seam welds (Category B-A, i Item No. Bl.ll) in the reactor vessel shell.

i "3. Inspection procedures used for these examinations shall be

qualified such that flaws relevant to vessel integrity shall be reliably detected and sized. Personnel implementing these l procedures shall be qualified in the use of these procedures.

! " Attached Table l', which is b'ased on Table 9-1 in EPRI TR-105697,

! identifies the calculated probabilities of RPV failures and leakage per l 40 vessel years due to postulated crack development and growth under each a of the two evaluated inspection programs, i.e., the Code-required program i

d program. Based on the resultant RPV

! versus the BWRVIP/EPRI-recommeny' failure probability of 1.151x10 /40 vessel years (for longitudinal and circumferential welds) as obtained for the BWRVIP/EPRI proposed inspection program, the RPV failure probability under the proposed j program would still be more than two orders of magnitude less than the 4

NRC spfety goal for reactor vessel failure of 1x10 per vessel year or 4x10' in 40 vessel years.

"As previously noted, IP has ultrasonically examined 50% of the RPV circumferential welds and almost 55% of the RPV longitudinal welds, based on examinations completed during RF-2 and RF-4. This is significantly

more than the. number of welds required per EPRI TR-105697 wherein an examination of 0% and 50% of the circumferential and longitudinal welds, respectively, was shown to still support the safety goal for failure probability of the RPV. Considering the estimated cost of examining the 4

'Not included in this report. l i

I

_ 19 _

a remaining welds, both in dollars and in person-rem, the hardship or cost of performing the additional inspections is not justified relative to the marginal safety benefit estimated to be gained by doing the additional g inspections."  :

Licensee's Prooosed Alternative Examination (as stated):

"IP proposes to adopt an inspection program of reduced scope for the I number of RPV circumferential and vertical welds to be examined, in accordance with the recommendations of EPRI TR-105697."

. Evaluation: The Code requires that the RPV shell welds receive 100%

l volumetric examination. In addition, 10 CFR 50.55a(g)(6)(ii)(A) mandates an augmented volumetric examination of all RPV shell welds (Item B1.10,

! Examination Category B-A) to the requirements specified in the 1989  :

, Edition of the Code during the first 10-year inspection interval at Clinton Power Station. The regulation requires that licensees examine i essentially 100% of these welds.

l 10 CFR 50.55a(g)(6)(ii)(A)(1) states that all reliefs previously granted l under $50.55a for the extent of volumetric examination of reactor vessel I

shell welds are revoked. Because of this regulatory requirement, any relief pertaining to volumetric examination of reactor vessel shell welds should not be granted. Alternatively, the augmented RPV examination may ,

serve as a substitute for the examination from which IP is requesting j relief. The RPV augmented examination aust be implemented and, if

necessary, an alternative should be proposed under the provisions of 10 CFR 50.55a(g)(6)(ii)(A)(5). Therefore, it is recommended that relief l be denied.

4 i

G. Reauest for Relief 4011. Examination Cateaory C-A. Item C1.20. RHR Heat Exchanaer Head-to-Shell Weld Code Reauirement: Section X'I, Table IWC-2500-1, Examination Category C-A, Item C1.20 requires a 100% ultrasonic examination of the head-to-shell welds in Class 2 pressure vessels during each inspection interval.

i h

l In the case of multiple vessels of similar design, the required examinations may be limited to one vessel or distributed among the vessels.

Licensee's Code Relief Reauest: The licensee requested relief from performing a complete Code-required ultrasonic examination of the Residual Heat Removal Heat Exchanger A, Weld Number HEA-1. The licensee j is examining approximately 87% of the required volume.

Licensee's Basis for Reauestina Relief (as stated):

"Four permanently welded / installed lifting lugs interfere with the ultrasonic examination. To perform examination of the entire volume, the lifting lugs would have to be removed by grinding.

representative lifting lug is attached as Figure 1., A drawing of a "ASME Code Case N-460 has been incorporated into Regulatory Guide 1.147, Rev. 11 dated October, 1994. This Code Case allows a reduction of the examination area of up to 10%. Another 3% reduction in the examination area for this weld would not significantly impact the effectiveness of the examination and should thus not compromise safety. To examine the required 3% additional examination area, Clinton Power Station (CPS) personnel would have to remove the four lugs by grinding. This would require erecting very large scaffolding all around the heat exchanger and removing an extensive amount of insulation. Further, this RHR heat exchanger is located in a high radiation area. All of this effort to support and perfom examination of the additional weld area would thus require Illinois Power Company to expend many unnecessary man-hours and incur a significant amount of exposure (estimated to be 3-4 man-rem)."

Licensee's Proposed Alternative Examination (as stated):

"Perfom the ultrasonic examination of the accessible area to the maximam extent feasible without removing the pemanently installed lifting lugs."

Evaluation: The Code requires that Class 2 pressure-retaining vessel head-to-shell welds receive 100% volumetric examination each inspection interval. The location of the permanent lifting lugs makes the examination impractical to perform to the extent required by the Code.

The licensee has ultrasonically examined approximately 87% of the subject j weld. This is a significant percentage and provides reasonable assurance l

l 'Not included in this report.

i'

• 1 I i of the continued structural integrity of the RHR heat exchanger. To j increase the examination coverage, the permanently installed lifting lugs

] would have to be removed, redesigned, and replaced.

l Based on the volumetric examination coverage obtained and the

! impracticality of removing the lifting lugs to increase examination j coverage, it is recommended that relief be granted as requested, pursuant to 10 CFR 50.55a(g)(6)(1).

t H. Reauest for Relief 4012. Examination Cateaory C-C. Ites C3.30.

l Intearally-Welded Attachments to the Reactor Core Isolation Coolina Pumo

! Code Reauirement: Section XI, Table IWC-2500-1, Examination Category

! C-C, Item C3.30 requires 100% surface examination of selected integral attachment welds as defined by Figure IWC-2500-5.

Licensee's Code Relief Reauest: The licensee requested relief from

performing a complete, Code-required surface examination of Reactor Core l Isolation Cooling (RCIC) pump Weld Number RCIC-1A(1-4).

i i

} Licensee's Basis for Reauestina Relief (as stated):

1 4

i "There are four identical lugs (integral attachments) welded to the RCIC l pump casing which are utilized to mount the pump to its pedestal. Once

. the pump is installed, the lower side of the weld (on each of the four

! lugs) is not accessible for examination. In order to perform the 3

examination on the lower side, the pump itself would have to be removed i from the pedestal. Attached Figure 1 is a drawing and photograph j indicating the positions of the pump lugs on the RCIC pump casing.

4 Figure 2 shows what was examined for emph of the lug welds for the surface examinations performed to date 1 "To gain access to the lower side of the lugs, the pump would have to be i removed from the pedestal. Apart from performing the examination itself, e

this would require disconnecting the piping from the pump, re-installing the pump back on the pedestal, reconnecting the piping, and verifying that everything is installed properly and meets design requirements.

This process would require Illinois Power Company (IP) to expend several

'Not included in this report.

i

I, ,

l man-hours and would result in unnecessary radiation exposure (estimated to be approximately 2 man-res). NRC nas incorporated Code Case N-460,

" Alternative Examination Coverage for Class 1 and 2 Welds", into Regulatory Guide 1.147, Rev.11 dated October,1994. This Code Case '

al' ows a reduction in the examination coverage up to 10%. In the case of this weld, RCIC-1A (1-4), IP cannot perform 16% of the examination area due to an interference with the pedestal. A reduction of another 6% in the examination coverage will not significantly reduce the margin of safety provided by performing the surface examination for verifying weld integrity."

Licensee's Proposed Alternative Examination (as stated):

" Perform the surface examination of the accessible area to the maximum extent feasible without removing the pump from its pedestal."

Evaluation: The Code requires that the subject Class 2 integral attachment weld receive 100% surface examination. However, due to inaccessibility caused by interference with the pump support pedestal, a complete surface examination of RCIC pump integral attachment weld RCIC-1A (1-4) is impractical. To perform the surface examination to the extent required by the Code, design modifications or replacement of the components with those of a design providing.for complete access would be required. Imposition of this requirement would cause a considerable burden on the licensee.

t The licensee proposes to perform the examination to the extent feasible.

Based on the 84% volumetric examination coverage obtained, it can be concluded that any pattern of degradation, if present, would be detected.

Therefore, pursuant to 10 CFR 50.55a(g)(6)(i), it is recommended that relief be granted as requested.

I. Reauest for Relief 4013. Examination Cateoory C-G. Ites C6.10. Class 2 Residual Heat p-val P- Casina Weld Code Renuirement: Section XI, Table IWC-2500-1, Examination Category C-G, Item C6.10 requires a 100% surface examination of pump casing welds j

! to be performed each inspection interval, as defined by Figure 3

IWC-2500-8. The examination may be performed from either the inside or 1  !

outside surface of the pump. If a system has multiple pumps of similar l

l

, o

(*

1 design, size, function, and service, only one pump among the group of similar pumps must be examined. )

Licensee's Code Relief Reauest: The licensee requested relief from performing the complete, Code-required surface examination on weld number RHR-A-2 of the "A" Resid'ual Heat Removal (RHR) pump.

Licensee's Basis for Reauestina Relief (as stated): I l

"A pemanently installed instrument line interferes with the surface examination of this weld. To perform a full Code-required examination of this area, the instrument line would have to be cut out to gain access.

" Code Case N-460 has been incorporated into Regulatory Guide 1.147, Rev. 11 dated October, 1994. This Code Case allows a reduction in the examination area of up to 10%. Another 3% reduction in the examination area would not significantly reduce the effectiveness of the examination for verifying weld integrity. To examine the Code-required 3% additional .

examination area, Clinton Power Station (CPS) personnel would have to cut out the noted instrument lina and weld it back. Further, the effort ,

I required would result in unnecessary radiation exposure to plant  !

personnel. Relative to the little or negligible safety benefit gained by

~

examining the obstructed weld' area, removal and repair of the instrument line, along with the radiation exposure incurred, is not justified."

l Licensee's Prcoosed Alternative Examination (as stated):

" Perform the surface examination of the accessible area to the maximum i extent feasible without removing the permanently installed instrument j line."

Evaluation: The Code requires a surface examination of the Class 2 RHR pump casing weld. However, a permanently installed instrument line limits access for a complete examination. Therefore, the Code-required examination is impractical for this weld. To perform the surface examination to the extent required by the Code, design modifications l would be necessary to provide sufficient access. Imposition of this requirement would cause a considerable burden on the licensee.

l The licensee is performing the Code-required surface examination on 87%

of the subject weld. Examination of this significant portion of the pump 1

s o f' A 9

casing weld should be sufficient to detect any pattern of degradation, if present. Therefore, based on the extent of surface examination being performed and the burden on the licensee if the Code requirement were imposed, it is recommended that relief be granted pursuant to 10 CFR 50.55a(g)(6)(1).

3.0 CONCLUSION

j The INEL staff has evaluated the licensee's submittal. For Requests for l Relief 4005, 4011, 4012, and 4013, the staff concludes that the j requirements of the Code are impractical and recommends that relief be l granted pursuant to 10 CFR 50.55a(g)(6)(1). For Request for Relief 4006, l it is recommended that relief be granted for those welds that have been examined. For those welds in Request for Relief 4006 that have not been examined, it is recommended that relief be denied. For Requests for Relief 4007 and 4008, compliance with the Code requirements would result in hardship or unusual difficulty without a compensating increase in quality or safety; therefore, it is recommended that relief be authorized pursuant to 10 CFR 50.55a(a)(3)(ii). ForRequestforRelief4009, itis!!dtryw recommended that use of a later Code be authorized pursuant to 10 CFR I" t 50.55a(g)(4)(iv). For Request for Relief 4010, it is recommended that

! relief be denied. The Code and the Regulations require that the licensee perform the examinations on the RPV shell welds. After these examinations are completed, if the licensee determines that the Code and Regulatory requirements for the RPV shell weld examinations cannot be l completely satisfied, an alternative to the examination requirements I shall be submitted pursuant to 10 CFR 50.55a(g)(6)(ii)(A)(5).

,