Text

Safety Evaluation Granting Proposed Alternative Pursuant to 10CFR50.55a(g)(6)(ii)(A)(5) & 10CFR50.55a(3)(ii) for Request Relief from 10CFR50.55a(g)(6)(ii)(A)(2) & from Requirements of Section XI of ASME Code
	ML18016A576
Person / Time
Site:	Harris
Issue date:	09/11/1998
From:	; NRC (Affiliation Not Assigned)
To:	;
Shared Package
ML18016A575	List: ML18016A574; ML18016A576;
References
	NUDOCS 9809160195
	Download: ML18016A576 (22)
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By letter dated December 16, 1997, as supplemented June 1, 1998, Carolina Power and Light (CP&L) requested relief from 10 CFR 50.55a(g)(6)(ii)(A)(2) and from the requirements of Section XI of the American Society of Mechanical Engineers (ASME) Code for the Shearon Harris Nuclear Power Plant (SHNPP).

Specifically, relief request R1-011A contained a proposed alternative to the augmented reactor vessel examination, and R1-011B requested relief from the ASME Code,Section XI examination categories B-A, B-D, and B-F for several reactor pressure vessel (RPV) welds. The relief requests are for the first 10-year interval.

BAMGtLODL The Technical Specifications (TS) for the Shearon Harris Nuclear Power Plant, Unit 1, (SHNPP) state that the inservice inspection of the American Society of Mechanical Engineers (ASME)

Code Class 1, 2, and 3 components shall be performed in accordance'with Section XI of the ASME Boiler and Pressure Vessel (B&PV) 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(6)(g)(l)

~ 10 CFR 50.55a(a)(3) states that alternatives to the requirements of paragraph (g) may be used, when authorized by the NRC, if(I) the proposed alternatives would provide an acceptable level of quality and safety or (ii) compliance with the specified requirements would result in hardship or unusual difficultywithout 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 10-year interval and subsequent intervals comply with the requirements in the latest edition and addenda of Section XI of the ASME Code incorporated by reference in 10 CFR 50.55a(b) 12 months prior to the start of the 120-month interval, subject to the limitations and modifications listed therein. The applicable edition of Section XI of the ASME Code for the SHNPP first 10-year inservice inspection (ISI) interval is the 1983 Edition through Summer 1983 Addenda.

Enclosure 9soqaeoxqs eso9xx PDR ADOCK 05000400 P

PDR Pursuant to 10 CFR 50.55a(g)(5)(iii), ifthe licensee determines that conformance with an examination requirement of Section XI of the ASME Code is not practical for its facility, the licensee shall submit information to the Commission in support of that determination and request relief from the ASME Code requirement.

After evaluation of the determination, pursuant to 10 CFR 50.55a(g)(6)(l), the Commission may grant relief and may impose alternative requirements that are determined to be authorized by law and willnot 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 ifthe requirements were imposed.

Pursuant to 10 CFR 50.55a(g)(6)(ii)(A)(5), the licensees that are unable to satisfy the requirements for the augmented reactor vessel weld examination specified in 10 CFR 50.55a(g)(6)(ii)(A) shall submit information to support the determination and propose an alternative that would provide an acceptable level of quality and safety, which may be authorized by the NRC.

3.0

&AEQUI The staff, 'with technical assistance from its contractor, the Idaho National Engineering and Environmental Laboratory (INEEL), has evaluated the information provided by the licensee in support of its alternative to 10 CFR 50.55a(g)(6)(ii)(A)(2) augmented reactor pressure vessel examination and request for relief from the requirements of the ASME Code,Section XI, for the SHNPP.

Based upon the results of this review, the staff adopts the contractor's conclusions and recommendations presented in the Technical Letter Report (TLR) attached.

Request for Relief R1-011A: In accordance with 10 CFR 50.55a(g)(6)(ii)(A), all licensees must implement once, as part of the inservice inspection interval in effect on September 8, 1992, an augmented volumetric examination of the RPV welds specified in Item B1.10 of Examination Category B-Aof the 1989 Edition of the ASME Code,Section XI.

Examination Category B-A, Items B1.11 and B1.12 require volumetric examination of essentially 100% of the RPV circumferential and longitudinal shell welds, as defined by Figures IWB-2500-1 and -2, respectively.

Essentially 100%, as defined by 10 CFR 50.55a(g)(6)(ii)(A)(2), is greater than 90% of the examination volume of each weld.

Pursuant to 10 CFR 50.55a(a)(3)(ii), the licensee has proposed an alternative to the augmented RPV examination coverage requirements because essentially 100% coverage could not be achieved for Weld B1.11 STHW-RV-04. Eighty percent coverage was achieved.

The licensee stated:

The Reactor Pressure Vessel (RPV) pressure retaining welds, including the lower shell to bottom head weld, are volumetrically (UT) examined to the maximum extent possible in accordance with the Inservice Inspection Program schedule.

In addition, the welds are subject to visual (VT-2) pressure tests during each refueling outage.

At Shearon Harris Nuclear Plant, the augmented examination requirements cannot be met for the lower head-to-shell weld due to physical restrictions that limitscan coverage.

Adjacent radial support lugs and weld transition surface geometry limitcoverage to 80% of the required Enclosure

examination volume. To obtain a 10% increase in coverage for the subject weld, design modifications would be required to allow access from the inside surface (ID). As a result of the augmented volumetric examination rule, licensees must make a reasonable effort to maximize examination coverage of their reactor vessels.

In cases where examination coverage from the ID is inadequate, examination from the outside surface (OD) using manual inspection techniques may be an option. However, extensive surface preparation would be required for the licensee to perform supplemental examinations from the outside diameter.

The effort expended to remove insulation and prepare the surface for the OD examination would result in radiological exposure that is not warranted for the additional 10% volumetric coverage.

Therefore, imposition of this requirement would result in a hardship without a compensating increase in the level of quality and safety.

The licensee has examined a significant portion of the subject weld (80%). Furthermore, the volumetric examination is supplemented with a visual (VT-2) examination of the welds during each refueling outage.

In addition, the licensee has met the coverage requirements for the remaining RPV shell welds.

Based on the volumetric examination coverage attained, examinations conducted on other RPV welds, and the visual examination, the staff concludes that any significant patterns of degradation, ifpresent, would have been detected and that the examinations performed provide reasonable assurance of the continued structural integrity of the subject lower head-to-shell weld. Therefore, the staff authorizes the licensee's proposed alternative pursuant to 10 CFR 50.55a(g)(6)(ii)(A)(5) and 50.55a(a)(3)(ii).

Request for Relief R1-011B (Part 1): ASME Code,Section XI, Examination Category B-A, Items B1.11 and'B1.30, requires 100% volumetric examination of the RPV circumferential shell and shell-to-flange weld lengths, as defined by Figures IWB-2500-1 and -4. Items B1.21 and B1.22 require 100% volumetric examination. of the accessible portion of all circumferential and meridional head welds, as defined by Figure IWB-2500-3.

In accordance with 10 CFR 50.55a(g)(5)(iii), the licensee requested relief from the Code-required 100% volumetric examination coverage for the welds listed below.

WELD ITEM DESCRIPTION COVERAGE LIMITATION STHW-RV-04 B1.11 CHW-RV-17 B1.21 MHW-RV-16 B1.22 FTSW-RV-01 B1.30 Lower Shell to Bottom Head Bottom Head Dome Meridional @

45deg.

Flange to Upper Shell 80%

67%

g0 67%

Radial Support Lugs and Weld Transition Instrumentation Tubes Instrumentation Tubes ID Surface Taper Enclosure

4 The Code requires 100% volumetric examination of the subject RPV welds.

However, complete examination coverage is restricted by physical obstructions and geometric surface conditions that make 100% volumetric examination impractical for these welds. To gain access for examination, the RPV would require design modifications.

Imposition of this requirement would impose a significant burden on the licensee.

The licensee has examined these welds to the extent practical; examination volumes achieved range from 67-90% of each weld.

In addition, other RPV welds have been examined to the extent required by the Code. Therefore, any existing patterns of degradation would have been detected by the examinations that were completed and reasonable assurance of structural integrity has been provided.

Based on the impracticality of meeting the Code examination coverage requirements for the subject welds, and the reasonable assurance provided by the examinations that were completed on these and other welds, relief is granted pursuant to 10 CFR 50.55a(g)(6)(l).

Request for Relief R1-0118 (Part 2): ASME Code Section XI, Examination Category B-D, Item B3.90, requires 100% volumetric examination of all nozzle-'to-vessel welds in the reactor pressure vessel, as defined by Figure IWB-2500-7.

In accordance with 10 CFR 50.55a(g)(5)(iii), the licensee requested relief from the Code-required volumetric examination for the welds listed below.

WELD ITEM DESCRIPTION COVERAGE LIMITATION RVNOZBO-N-02 RVNOZBO-N-04 RVNOZBO-N-06 B3.90 B3.90 B3.90 Outlet Nozzle

@265 deg.

Outlet Nozzle

@145 deg.

Outlet Nozzle

@25 deg.

60 80%

60 Integral Extension Integral Extension Integral Extension The Code requires 100% volumetric examination of the subject RPV nozzle-to-vessel welds.

However, complete examination is restricted by physical obstructions and geometric surface conditions that make the 100% volumetric examination impractical for these areas.

To gain access for examination, the RPV nozzles would require design modifications.

Imposition of this requirement would result in a burden on the licensee.

The licensee has examined the subject welds to the extent practical, obtaining 80% coverage of each nozzle-to-vessel weld.

In addition, other Class 1 nozzle-to-vessel welds were examined as required by the Code.

Therefore, any existing patterns of degradation would have been detected by the examinations that were completed and reasonable assurance of the structural integrity has been provided.

Enclosure

Based on the impracticality of meeting the Code examination requirements for the subject nozzle-to-vessel welds, and the reasonable assurance provided by the examinations that were completed on these and other Class 1 nozzles, relief is granted pursuant to 10 CFR 50.55a(g)(6)(I).

Relief Request R1-011B (Part 3): ASME Code Section XI, Examination Category B-F, Item B5.10, requires 100% volumetric and surface examination of all nozzle-to-safe end reactor vessel welds, as defined by Figure IWB-2500-8.

In accordance with 10 CFR 50.55a(g)(5)(iii), the licensee requested-relief from the Code-required 100% volumetric examination of the welds listed below.

WELD ITEM DESCRIPTION COVERAGE LIMITATION RVNOZAI-N-01-SE B5.10

'VNOZBO-N-02-SE B5.10 Safe End to Inlet Nozzle 335 deg Outlet Nozzle to Safe End @265 deg.

7 76%

ID Surface Counterbore ID Surface Counterbore The Code requires 100% volumetric and surface examination of the subject nozzle-to-safe end butt welds. However, complete examination is restricted due to geometric surfaces (ID surface counterbore) that make the 100% volumetric examination impractical for these areas.

To gain additional coverage, the RPV nozzles would require design modifications.

Imposition of this requirement would result in a burden on the licensee.

The licensee has examined a significant portion of the welds, obtaining 74 to 76% coverage for each nozzle-to-safe end weld. In addition, other Class 1 nozzle-to-safe end welds were examined as required by the Code.

Therefore, any existing patterns of degradation would have been detected by the examinations that were completed and reasonable assurance of the structural integrity has been provided.

Based on the impracticality of meeting the Code coverage requirements for the subject nozzle-to-safe end welds, and the reasonable assurance provided by the examinations that were completed on these and other Class 1 nozzles, relief is granted pursuant to 10 CFR 50.55a(g)(6)(I).

4.0 GOOSO I The staff has reviewed the licensee's submittal and concludes that, for Relief Request R1-011A, full compliance with the augmented reactor pressure vessel examination requirements would result in hardship without a compensating increase in the level of quality and safety.

Therefore, the staff has authorized the proposed alternative pursuant to 10 CFR 50.55a(g)(6)(ii)(A)(5) and 10 CFR 50.55a(3)(ii). For Request for Relief R1-011B (Parts 1-3), it Enclosure k

is concluded that the Code requirements are impractical. Therefore, the staff has granted relief pursuant to 10 CFR 50.55a(g)(6)(l).

Principal Contributor: T. McLellan Date: September ll, 1998 Enclosure

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1.0 By [[letter::HNP-98-078, Forwards Response to 980507 RAI Re GL 97-04, Assurance of Sufficient NPSH for ECC & Containment Heat Removal Pumps|letter dated June 1, 1998]], the licensee, Carolina Power tk Light Company, submitted Revised Requests for Relief Nos. R1-011A and R1-011B seeking relief from the augmented examination of the reactor pressure vessel (RPV) required by 10 CFR 50.55a(g)(6)(ii)(A) and the requirements of the ASME Code,Section XI, for

the Shearon Harris Nuclear Power Plant.

These relief requests are for the first 10-year inservice inspection interval. The Idaho National Engineering and Environmental Laboratory (INEEL) staff has evaluated the information provided by the licensee regarding the proposed alternative and the request for relief in the following section.

2.0 The Code of record for Shearon Harris Nuclear Power Plant's first 10-year inservice inspection (ISI) interval is the 1983 Edition through Summer 1983 Addenda of Section XI of the ASME Boiler and Pressure Vessel Code.

The first 10-year interval began May 2, 1987.

The information provided by Carolina Power 5 Light Company in support of the request for relief from Code requirements and the proposed alternative to augmented reactor vessel examinations has been evaluated, and the bases for disposition are documented below.

ATTACHMENT

A.

In accordance with 10 CFR 50.55a(g)(6)(ii)(A), all licensees must implement once, as part of the inservice inspection interval in effect on September 8, 1992, an augmented volumetric examination of the RPV welds specified in Item B1.10 of Examination Category B-A of the 1989 Edition of the ASME Code,Section XI. Examination Category B-A, Items B1.11 and B1

~ 12 require volumetric examination of essentially 100% of the RPV circumferential and longitudinal shell welds, as defined by Figures IWB-2500-1 and -2, respectively.

Essentially 100%, as defined by 10 CFR 50.55a(g)(6)(ii)(A)(2), is greater than 90% of the examination volume of each weld.

Pursuant to 10 CFR 50.55a(a)(3)(ii), the licensee has proposed an alternative to the augmented RPV examination coverage requirements because essentially 100% coverage could not be achieved for Weld B1.11 STHW-RV-04. Eighty percent coverage was achieved.

The'licensee stated:

"The Reactor Pressure Vessel (RPV) pressure retaining welds, including the lower shell to bottom head weld, are volumetrically (UT) examined to the maximum extent possible in accordance with the Inservice Inspection Program schedule.

In addition, the welds are subject to visual (VT-2) pressure tests during each refueling outage."

(as stated):

"The subject weld received limited examination coverage due to physical obstructions and nonconducive geometric surface conditions.

The obstructions physically prevent 100 percent examination coverage of the subject weld volume.

The nonconducive geometric surface conditions prevent sufficient sound propagation into the weld examination volume at specific locations, therefore 100 percent examination coverage is not achievable.

Attempting to perform supplemental examinations from the outside surface would have required extensive surface preparation and

expended unwarranted dose without a commensurate increase in the level of reliability, quality, or safety."

"Pressure retaining welds in the RPV, including the lower shell to bottom head weld, have been volumetrically (UT) examined to the maximum extent possible during preservice and first interval inservice examinations with no rejectable indications noted.

The design configuration introduces obstructions and nonconducive surface conditions that prevent 100 percent volumetric examination coverage.

The minimal number and magnitude of indications recorded during the preservice examinations and first interval inservice examinations indicate that the majority of the vessel examination volume is free of detrimental discontinuities.

Therefore, the likelihood of the limited areas not examined due to physical obstructions having a rejectable indication is minimal ~ The RPV examinations have been performed utilizing the state of the art examination equipment, techniques and data recording/analysis systems.

Additionally, Performance Demonstration Initiative procedures, qualified personnel and techniques were utilized as a conservative measure to incorporate the current industry practice and technology."

To comply with the augmented reactor vessel examination requirements of 10 CFR 50.55a(g)(6)(ii)(A), licensees must volumetrically examine essentially 100% of each of the Item B1.10 shell welds.

In accordance with the regulations, essentially 100% is defined as greater than 90% of the examination volume of each weld, At Shearon Harris Nuclear Plant, the augmented examination requirements cannot be met for the lower head-to-shell weld due to physical restrictions that limit scan coverage.

Adjacent radial support lugs and weld transition

)

surface geometry limit coverage to 80% of the required examination volume.

To obtain a 10% increase in coverage for the subject weld, design modifications would be required to allow access from the inside surface (ID).

As a result of the augmented volumetric examination rule, licensees must make a reasonable effort to maximize examination coverage of their reactor vessels.

In cases where examination coverage from the ID is inadequate, examination from the outside surface (OD) using manual inspection

techniques may be an option.

However, extensive surface preparation would be required for the licensee to perform supplemental examinations from the outside diameter.

The effort expended to remove insulation and prepare the surface for the OD examination would result in radiological exposure that is not warranted for the additional 10% volumetric coverage. Therefore, imposition of this requirement would result in a hardship without a compensating increase in the level of quality and safety.

The licensee has examined a significant portion of the subject weld (80%).

Furthermore, the volumetric examination is supplemented with a visual (VT-2) examination of the welds during each refueling outage.

In addition, the licensee has met the coverage requirements for the remaining RPV shell welds.

Based on the volumetric examination coverage attained, examinations conducted on other RPV welds, and the visual examination, the INEEL staff concludes that any significant patterns of degradation, if present, would have been detected and that the examinations performed provide reasonable assurance of the continued structural integrity of the subject lower head-to-shell weld. Therefore, it is recommended that the licensee's proposed alternative be authorized pursuant to 10 CFR 50.55a(a)(3)(ii).

Examination Category B-A, Items B1.11 and B1.30, require 100% volumetric examination of the RPV circumferential shell and shell-to-flange weld lengths, as defined by Figures IWB-2500-1 and -4. Items 81.21 and B1.22 require 100% volumetric examination of the accessible portion of all circumferential and meridional head welds, as defined by Figure IWB-2500-3.

In accordance with 10 CFR 50.55a(g)(5)(iii),

the licensee requested relief from the Code-required 100% volumetric examination c'overage for the welds listed below, WELD ITEM DESCRIPTION COVERAGE LIMITATION STHW-RV-Q4 "

CHW-RV-17 MHW-RV-16 FTSW-RV-Q1 B1.11 B1.21 B1.22 B1.3Q Lower Shell to Bottom Head Bottom Head Dome Meridional 9 45deg.

Flange to Upper Shell BQ%

67%

9Q%

67%

Radial Support Lugs and Weld Transition Instrumentation Tubes Instrumentation Tubes ID Surface Taper I

'v (as stated):

"Pursuant to 10 CFR 50.55a(g)(6)(i), relief is requested on the basis that the original examination requirements have been determined to be impractical.

"The subject welds received limited examination coverage due to physical obstructions and nonconducive geometric surface conditions.

The obstructions physically prevent 100 percent examination coverage of the subject weld volume.

The nonconducive geometric surface conditions prevent sufficient sound propagation into the weld examination volume at specific locations, therefore 100 percent examination coverage is not achievable.

Attempting to perform supplemental examinations from the outside surface would have required extensive surface preparation and expended unwarranted dose without a commensurate increase in the level of reliability, quality, or safety."

"Pressure retaining welds in the RPV have been volumetrically (UT) examined to the maximum extent possible during preservice and first interval inservice examinations with no rejectable indications noted.

The design configuration introduces obstructions and nonconducive surface conditions that prevent 100 percent volumetric examination coverage.

The minimal number and magnitude of indications recorded during the preservice examinations and first interval inservice examinations indicate that the majority of the vessel examination volume is free of detrimental discontinuities.

Therefore, the likelihood of the limited areas not examined due to physical obstructions having rejectable indication is minimal. The RPV examinations have been performed utilizing the state of the art examination equipment, techniques

~

P C

and data recording/analysis systems.

Additionally, Performance Demonstration Initiative procedures, qualified personnel and techniques were utilized as a conservative measure to incorporate the current industry practice and technology, and penetrant examinations were performed on category B-A, Item Number B3.90 and B5.10 welds with no rejectable indications noted."

(as stated):

"The Reactor Pressure Vessel (RPV) pressure retaining welds are volumetrically (UT) examined to the maximum extent possible in accordance with the Inservice Inspection Program schedule.

In addition, the welds are subject to visual (VT-2) pressure tests during each refueling outage."

The Code requires 100% volumetric examination of the subject RPV welds.

However, complete examination coverage is restricted by physical obstructions and geometric surface conditions that make 100%

volumetric examination impractical for these welds.

To gain access for examination, the RPV would require design modifications.

Imposition of this requirement would impose a significant burden on the licensee.

The licensee has examined these welds to the extent practical; examination volumes achieved range from 67-90% of each weld.

In addition, other RPV welds have been examined to the extent required by the Code.

Therefore, any existing patterns of degradation would have been detected by the examinations that were completed and reasonable assurance of structural integrity has been provided.

Based on the impracticality of meeting the. Code examination coverage requirements for the subject welds, and the reasonable assurance provided by the examinations that were completed on these and other welds, it is recommended that relief be granted pursuant to 10 CFR 50.55a(g)(6)(i).

C.

e

'/

volumetric examination of all nozzle-to-vessel welds in the reactor pressure vessel, as defined by Figure IWB-2500-7.

I' In accordance with 10 CFR 50.55a(g)(5)(iii),

the licensee requested relief from the Code-required volumetric examination for the welds listed below.

WELD ITEM DESCRIPTION COVERAGE LIMITATION RVNOZBO-N-02 RVNOZBO-N-04 RVNOZBO-N-06 B3.90 B3.90 B3.90 Outlet Nozzle 9 265 deg.

Outlet Nozzle 9 1'45 deg.

Outlet Nozzle 9 25 deg.

80%

80 80%

Integral Extension Integral Extension Integral Extension (as stated):