ML20195H100

Safety Evaluation of First Containment Insp Interval Iwe/Iwl Program Alternative

ML20195H100
Person / Time
Site:	Calvert Cliffs
Issue date:	11/16/1998
From:	NRC (Affiliation Not Assigned)
To:
Shared Package
ML20195H078	List: ML20195H073 ML20195H100
References
NUDOCS 9811230257
Download: ML20195H100 (10)

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t png g-k UNITED STATES g j NUCLEAR REGULATORY COMMISSION o WASHINGTON, D.C. 20806 0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATICN OFTHE FIRST CONTAINMENT INSPECTION INTERVAL IWEllWL PROGRAM ALTERNATIVE FOR CALVERT CLIFFS NUCLEAR POWER PLANT. UNIT NOS.1 AND 2

1.0 INTRODUCTION

By letter dated June 8,1998, the licensee, Baltimore Gas and Electric Company (BGE),

submitted Requests for Relief (Nos. E1, E2, and L1), seeking relief from certain requirements of the ASME Code, Section XI, for the Calvert Cliffs Nuclear Power Plant, Unit Nos.1 and 2 ,

(Reference 1). These relief requests have been subrnitted during the second 10-year inservice inspection (ISI) interval for Class I,11, and lit components. However, the licensee has elected to begin a separate containment inspection interval. The first period of the first containment inspection interval for IWEllWL at Calvert Cliffs Nuclear Power Plant, Unit Nos.1 and 2 is from September 9,1998 to September 9,2001. The staff's safety evaluation of BGE's requests for relief, based on the technical evaluation report prepared by Idaho National Engineering and Environmental Laboratory (INEEL) on this subject (Enclosure 2), is provided below.

2.0 EVALUATION Recuest for Relief No. E1. Examination Cateaorv E-D. Items E5.10 and E5.20 of IWE-2500.

Table IWE-2500-1. Visual Examination of Seals and Gaskets The Code requires that seals and gaskets on air locks, hatches, and other devices be VT-3 visually examined once each interval to assure containment leak-tight integrity. The licensee proposes to use the existing 10 CFR Part 50, Appendix J testing as a verification of containment integrity, rather than disassembling the subject components for the sole purpose of examination.

The 1993 Addenda to Section XI has recognized that disassembly of joints, for the sole purpose of performance of the visual examination, is unwarranted. The staff believes that the functionality of the containment penetration seals and gaskets would be verified during the Type B testing as required by 10 CFR Part 50, Appendix J. Consequently, the proposed altemative provides an acceptable level of quality and safety. Therefore, the licensee's proposed altemative contained in Relief Request E1 is authorized pursuant to 10 CFR 50.55a(a)(3)(i).

Reauest for Relief No. E2. IWE-2420(b) Successive Examinations After Repair Paragraph IWE-2420(b) requires that when examinations result in evaluation of flaws or areas of degradation (per IWE-3000), and the component is acceptable for continued service, or when examinations result in performance of a repair / replacement activity, the items containing such 9811230257 981116 PDR ADOCK 05000317 G PDR Enclosure 1

4 flaws, areas of degradation, or areas subjected to a repair / replacement, shall be re-examined during the next inspection period. The licensee is proposing not to perform any reexaminations during the next examination period when the gomponent is restored, via repair or replacement activities, to an acceptable condition for continued service in accordance with the acceptance ,

standards of IWE-3000. This approach is consistent with the successive examination i requirements of Class 1,2 and 3 components.

The NRC staff agrees with the licensee that a successive examination performed in the next period is not warranted after repair or replacement of the component. This position will be reflected in the 1998 Edition of Section XI. Therefore, the licensee's proposed attemative to omit the performance of successive examinations after repair and replacement activities will provide an acceptable level of quality and safety. Therefore, the licensee's proposed altemative contained in Relief Request E2 is authorized pursuant to 10 CFR 50.55a(a)(3)(i).

l Reauest for Relief No. L1. Suboaraaraoh IWL-2310. Visual Examination and Personnel Qualification for Containment To comply with the expedited examination of containment required by 10 CFR 50.55a(g)(6)(ii)(B), licensees must perform visual examinations on Class MC and Metallic Liners of Class CC Concrete Components pw the requirements of IWE, and visual examinations on ,

Class CC Concrete Components per the requirements of IWL of ASME Section XI.

The licensee has proposed an altemative to the requirements for the measurement of illumination and examination distance for visual examinations. The visual examinations on containment are performed to determine if damage or degradation, including cracks, wear, j l

corrosion, erosion or other physical damage, warrant additional evaluation or repair of the l structure. In order for the visual examinations to be performed in such a way as to detect critical l flaws, proper lighting is essential. The licensee has provided an attemative to Code I requirements that uses a combination of character size (s) and workmanship-based samples to determine the resolution required to ensure that indications that might challenge containment integrity are detectable. Paragraph IWL-3111, Acceptance of Concrete, requires that the Responsible Engineer determine what surface conditions are acceptable and ensure there is no evidence of damage or degradation sufficient to warrant further evaluation or repair. Therefore, the licensee's Responsible Engineer will identify the minimum flaw size (indications of interest) required to be detected. For remote visual examinations, procedures and equipment used will be demonstrated to be capable of detecting and resolving these indications. The licensee will maintain a record of the demonstration performed.

While the use of the licensee's proposed attemative does not result in a quantitative evaluation of the illumination, it provides a method to verify that the indications of interest are visually detectable. The staff determined that samples representing these indications provide an appropriate simulation and concludes that visual verification, via direct or remote means, provides sufficient evidence of adequate illumination and examination distance. Based on this, the staff concludes that the licensee's proposed altemative provides an acceptable level of quality and safety and, therefore, the licensee's proposed attemative contained in Relief Request L1 is authorized pursuant to 10 CFR 50.55a(a)(3)(i).

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3.0 CONCLUSION

The staff has evaluated the licensee's June 8,1998 submittal (Reference 1) for the Calvert Cliffs Nuclear Power Plant Units 1 and 2, and concluded that the proposed attematives contained in Requests for Relief Nos. E1, E2, and L1 provide an acceptable level of quality and safety and, therefore, the licensee's proposed allematives are authorized pursuant to 10 CFR 50.55a(a)(3)(i).

Reference:

1. Letter dated June 8,1998, from C.H. Cruse, BGE, to NRC.

Subject:

Calvert Cliffs Nuclear Power Plant, Units 1 and 2, Requests for Relief from Certain ASME Code Requirements for Inservice inspection.

f Principal Contributor: R. Pichumani Date: November, 16, 1998 r

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TECHNICAL LETTER REPORT ON FIRST CONTAINMENT INSPECTION INTERVAL IWEllWL PROGRAM REQUESTS FOR REllEF E1. E2. AND L1 FOR BALTIMORE GAS AND ELECTRIC COMPANY CALVERT CLIFFS NUCLEAR POWER PLANT. UNIT NOS.1 AND 2 DOCKET NUMBERS: 50-317 AND 50-318

1. INTRODUCTION By letter dated June 8,1998, the licensee, Baltimore Gas and Electric Company, submitted Requests for Relief E1, E2, and L1, seeking relief from the requirements of the ASME Code, Section XI, for the Calvert Cliffs Nuclear Power Plant, Unit Nos.1 and 2.

These relief requests have been submitted during the second 10-year inservice inspection (ISI) interval. However, the licensee has elected to begin a separate containmentinspection interval, as noted below. The Idaho National Engineering and Environmental Laboratory (INEEL) staff's evaluation of the subject requests for relief is in the following section.

2. EVALUATION The information provided by Baltimore Gas and Electric Company in support of the requests for relief from Code requirements has been evaluated and the bases for disposition are documented below. The Code of record for the Calvert Cliffs Nuclear Power Plant, Unit Nos.1 & 2, second 10-year ISI interval, which began April 1,1987 for both units, is the 1983 Edition, Summer 1983 Addenda of Section XI of the ASME Boiler and Pressure Vessel Code. The containment sections (IWE and IWL) of the subject j plants' ISI programs were developed in accordance with the requirements of the 1992 Edition,1992 Addenda of Section XI, as required by 10 CFR50.55a(g)(6)(ii)(B). The first period of the first containment inspection interval for IWE/lWL at Calvert Cliffs Nuclear Power Plant Units 1 and 2 is September 9,1998 to September 9,2001.

A. Reauest for Relief No. E1. Examination Cateaorv E-D. Items E5.10 and E5.20.

Visual Examination of Seals and Gaskets Code Reauirement: Examination Category E-D, item E5.10 and E5.20, requires 100% visual examination (VT-3) during each inspection interval, for seals and gaskets on air locks, hatches, and other devices that are required to assure containment leak-tight integrity.

Licensee's Proposed Attemative: In accordance with 10 CFR 50.55a(a)(3)(i), the licensee proposed to test the subject seals and gaskets in accordance with 10 CFR Part 50, Appendix J. Specifically, the following seals and gaskets are included in this proposal:

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i Electrical penetrations fitted with flexible metal seal assemblies; Air lock door seals, including door operating mechanism penetrations that are part of the containment pressure boundary; I

l Containment penetrations and valves whose design incorporates resilient seals, l gaskets, or sealant compounds; and Doors with resilient seals or gaskets except for seal-welded doors l Licensee's Basis for Proposed Attemative (as stated):

" Title 10 CFR 50.55a was amended in the Federal Register (61FR 41303) to require the use of the ASME B&PV Code, Section XI,1992 Edition,1992 Addenda, when performing containment examinations. The penetrations discussed below are part of the containment examination:

l Electrical penetrations Two types of electrical penetration assemblies are used: canister and unitized ,

header. All electrical penetration assemblies are fabricated and tested in accordance with the ASME B&PV Code, Section lit, Nuclear Vessel Code. The canister type is inserted in a nozzle of suitable diameter integral with the Containment Structure and field welded on the inside end. The unitized header type is welded to the nozzle on the outside end. These seals and gaskets cannot be inspected without the disassembly of the penetration to gain access to the seals and gaskets. All penetration assemblies are currently leak tested in accordance with 10 CFR Part 50, Appendix J, Option B.

Air lock door seals, including door operating mechanism penetration, which are part of the containment pressure boundary; The Personnel and Emergency Air Locks utilize an inner and outer door with gasket surfaces to ensure leak-tight integrity. These air locks also contain other gaskets and seals, such as the handwheel shaft seals, electrical penetrations, blank flanges, and equalizing pressure connections, which require disassembly to gain access to the gaskets and seals. Both access assemblies are currently leak tested in accordance with 10 CFR Part 50, Appendix J, Option B.

Containment penetrations and valves whose design incorporates resilient seals, gaskets, or sealant compounds; Containment purge blind flanges, fuel transfer tube blind flanges, and other penetration terminations contain gaskets and seals, which require disassembly to gain access to the gaskets and seals; these penetrations are currently leak tested i

in accordance with 10 CFR Part 50, Appendix J, Option B.

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Doors with resilient seals or gaskets except for seal-welded doors; The equipment hatch is a single door, utilizing a double gasket to ensure leak-tight integrity. The equipment hatch is currently leak tested in accordance with 10 CFR Part 50, Appendix J, Option B.

"The visual examination of seats and gaskets requires that the joints and valves, which are proven adequate through Appendix J leak rate tests, be disassembled.

For the electrical penetrations, this involves a pre-maintenance Appendix J leak l rate test, disconnecting cables at electrical penetrations, if enough cable slack is  !

not available, disassembly of the joint, removal and examination of the seals and gaskets, reassembly of the joint, reconnecting the cables if necessary, post-l maintenance testing of the cables, and then a post-maintenance Appendix J leak rate test of the penetration. For the Containment Personnel and Emergency Air Locks, blind flanges, and the equipment hatch, the work required would be similar

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except for the disconnecting, reconnecting, and testing cables. This imposes the 1 l risk that equipment could be damaged. If disassembly were not required, the VT-l 3 inspection of exposed surfaces of seals and gaskets would provide less assurance than that provided by the 10 CFR Part 50, Appendix J leak rate test.

" Seals and gaskets are not included as part of the containment pressure bouadary under current Section til Code rules (NE-2110 (b)], the Code under which Calvert Cliffs Nuclear Power Plant was constructed. When the air locks and hatches containing these materials are tested in accordance with 10 CFR Part 50, Appendix J, degradation of the seal or gasket materialis revealed by an increase in the leakage rate. In this case, corrective measures are applied and the component retested. Repair or replacement of seals and gaskets is not subject to Code (1992 Edition,1992 Addenda) rules in accordance with ASME B&PV Code, Section XI, Paragraph IWA-4111(b)(5).

l Relief is requested in accordance with 10 CFR 50.55a(a)(3)(i). Testing the seals and gaskets in accordance with 10 CFR Part 50, Appendix J, provides adequate assurance of the leak-tight integrity of the seals and gaskets."

Evaluation: The Code requires that seals and gaskets on air locks, hatches, and other devices be VT-3 visually examined once each interval to assure containment leak-tight integrity. The licensee proposes to use the existing 10 CFR 50, Appendix J testing as a verification of containment integrity, rather than disassembling the subject components for the sole purpose of examination. The 1993 Addenda to Section XI has recognized that disassembly of joints, for the sole purpose of performance of the visual examination, is unwarranted. The INEEL staff believes that the functionality of the containment penetration seals and gaskets would be verified during the Type B testing as required by 10 CFR Part 50, Appendix J. Consequently, the proposed attemative provides an l acceptable level of quality and safety. Therefore, it is recommended that the proposed altemative be authorized pursuant to 10 CFR 50.55a(a)(3)(i).

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B. Reauest for Relief No.'E2. lWE-2420(b) Successive Examinations After Repair Code Reauirement: Paragraph IWE-2420(b), requires that when component examination results require evaluation of flaws, evaluation of areas of degradation, or repairs in accordance with IWE-3000, and the component is found to be acceptable for continued service, the areas containing such flaws, )

l degradation, or repairs shall be reexamined during the next inspection period. j The reexaminations shall be performed in accordance with Examination Category l E-C and at the schedule specified in the inspection requirements of IWE-2411 or l IWE-2412.

i Licensee's Proposed Altemative: In accordance with 10 CFR 50.55a(a)(3)(i), the licensee proposed to restore components to original condition and eliminate the successive examination requirement. The licensee stated: '

" Relief is requested from the requirement of Paragraph IWE-2420(b) to perform successive examinations after repairs are made, examined, and the component retumed to service. Repairs will be performed in accordance with IWA-4000, to restore the component to its original condition." l Licensee's Basis for Proposed Altemative (as stated):

" Title 10 CFR 50.55a was amended in the Federal Register (61 FR 41303) to require the use of the ASME B&PV Code, Section XI,1992 Edition,1992 i Addenda, when performing containment examinations. The purpose of a repair is to restore the component to an acceptable condition for continued service in accordance with the acceptance standards of Article IWE-3000. When making repairs, paragraph IWA-4150 requires the owner to conduct an evaluation of the  ;

suitability of the repair, including consideration of the cause of failure.

" Repairs are performed in accordance with IWA-4000, the intent of which is to use the construction code to restore the component to its original condition. If the examination after a repair indicates that the repair has restored the component to an acceptable condition, successive examinations are not warranted. If the post-repair examination indicates the repair was not suitable, then the repair does not meet Code requirements and the component is not acceptable for continued service; further repair work would be necessary. Neither Paragraphs IWB-2420(b), IWC-2420(b), nor IWD-2420(b) require that a repair be subject to successive examination requirements. Additionally, if the repair area is subject to accelerated degradation, the repair would still require augmented examination in accordance with Table IWE-2500-1, Examination Category E-C.

"Reliefis requested in accordance with 10 CFR Part 50.55a(a)(3)(i). Repairing components to restore the component to its original condition provides adequate assurance of the integrity of the repair."

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l j Evaluation: Pa'ragraph IWE-2420(b) requires that when examinations result in i evaluation of flaws or areas of degradation (per IWE-3000), and the component is acceptable for continued service, or when examinations result in performance of a l repair / replacement activity, the items containing such flaws, areas of degradation.

l- or areas subjected to a repair / replacement, shall be re-examined during the next l Inspection period. The licensee is proposing not to perform any reexaminations l during the next examination period when the component is restored, via repair or l

replacement activities, to an acceptable condition for continued service in accordance with the acceptance standards of IWE-3000. This approach is consistent with the successive examination requirements of Class 1,2, and 3 l

components.

The INEEL staff agrees with the licensee that a successive examination performed in the next period is not warranted after repair or replacement of the component. This position will be reflected in the 1998 Edition of Section XI.

Therefore, the licensee's proposed altemative to not perform successive examinations after repair and replacement activities will provide an acceptable level of quality and safety. Therefore, it is recommended that the licensee's proposal be authorized pursuant to 10 CFR 50.55a(a)(3)(i) until such time as the requirement is published in a future Edition of ASME Section XI that has been .

accepted by the regulations. At that time, if the licensee intends to continue to implement this Request for Relief, the licensee should follow all provisions and requirements as found in the new edition of ASME Section XI.

C. Recuest for Relief No. L1. Suboaraaraoh IWL-2310. Visual Examination and Personnel Qualification for Containment Code Reauirement: IWL-2310 invokes paragraph IWA 2210, requiring specific minimum illumination and maximum direct examination distance for all concrete surfaces.

Licensee's Proposed Attemative: In accordance with 10 CFR 50.55a(a)(3)(i), the licensee proposed extending the maximum direct examination distance and reducing the minimum illumination requirements. The licensee stated:

" Perform the concrete surface inspection remotely as required by Subsection IWL, Paragraph IWL-2510, extending the maximum direct examination distance, and reducing the minimum illumination requirements specified in Table IWA-2210-1."

Licensee's Basis for Proposed Altemative (as stated):

" Title 10 CFR 50.55a was amended in the Federal Register (61 FR 41303) to require the use of the ASME B&PV Code, Section XI,1992 Edition,1992 l~ . Addenda, when performing containment examinations. In addition in the requirements of Subsection lWL, the rulemaking also imposes the requirements of ASME B&PV code, Section XI,1992 Edition,1992 Addenda, Subsection IWA for j minimum illumination and maximum direct examination distance of Class CC

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i "In accordance with IWA-2210, when remotely performing the visual examinations

required by Subsection lWL, Paragraph IWL-2510, using remote techniques, the

maximum direct examination distance specified in Table IWA-2210-1 may be decreased. The change in examination and illumination requirements are allowed pmvided the remote examination procedure is demonstrated to resolve the required test chart characters in Table IWA-2210-1. In lieu of using the Table l IWA-22101 test chart characters, the Responsible Engineer will use a 2

combination of character- and workmanship-based samples to determine the t

. resolution required to ensure that indications of interest are detectable. The l

] Responsible Engineer will also identify the minimum size for indications of j interest. For remote visual examination, the procedure and equipment to be used

, will be demonstrated capable of resolving these minimum indications to the j satisfaction of the Responsible Engineer and the Inspector. The record of demonstration will be available to the regulatory authorities.

l "In order to conform with Section XI, IWA-2000 requirements for visual l

,' examination, Subsection IWL referen6ed type VT-1 and VT-3 examinations, as -

described in ASME XI, IWA-2211 and -2213, respectively, but designated them VT-1C and VT-3C to signify that these were examinations of a concrete structure.

j The original VT-1 and VT-3 examinations in subsection IWA were designed for use on metal surfaces. Flaw detection on metal surfaces requires the ability to

, resolve a much smaller indication than that required on concrete due to the small 1

grain size of a metal surface in comparison to the much larger grain size of a poured concrete surface. The visual examination requirements forillumination levels and examination distances preclude the ability to demonstrate that the 3 remote visual examination is equivalent to direct visual examination when performing examinations of concrete surfaces. The visual examination of a 4 concrete Containment is intended to uncover indications of significant conditions i over a large area in a generally benign environment.

! "In subsequent editions of the ASME code, the requirements for a VT-1C

examination have been replaced with a ' detailed visual examination,' and the

requirements for a VT-3C examination have been replaced with a ' general visual examination.' The general visual examination of concrete surface is performed i,

under the direction of the Responsible Engineer to indicate the general structural condition of the containment. lWL-2000 references American Concrete Institute i ACl-2021.1 R-68 for guidelines used to determine concrete deterioration and 1

distress. If the general visual examination detects any deterioration, the detailed L

visual examination is performed, again under the direction of the Responsible

Engineer, to determine the magnitude and extent of the deterioration. Also, altemative lighting and resolution requirements have been added to later editions of Subsection IWL to be used in lieu of the requirements of IWA-2000.

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Relief is requested in accordance with 10 CFR 50.55a(a)(3)(i). Inspecting the concrete surfaces using increased distances and decreased illumination requirements, approved by that Responsible Engineer, will still allow the detection of flaws of a size sufficient to present a structural problem with the concrete."

Evaluation: To comply with the expedited examination of containment required by 10 CFR 50.55a(g)(6)(ii)(B), licensees must perform visual examinations on Class MC and Metallic Liners of Class CC Concrete Components per the requirements of IWE, and visual examinations on Class CC Concrete Components per the requirements of IWL of ASME Section XI.

l The licensee has proposed an attemative to the requirements for the measurement of illumination and examination distance for visual examinations.

The visual examinations on containment are performed to determine if damage or degradation, including cracks, wear, corrosion, erosion or other physical damage, warrani additional evaluation or repair of the structure. In order for the visual i examinations to be performed in such a way as to detect critical flaws, proper lighting is essential. The licensee has provided an attemative to code  !

requirements that uses a combination of character size (s) and workmanship . j based samples to determine the resolution required to ensure that indications that I might challenge containment integrity are detectable. Paragraph IWL-3111, Acceptance of Concrete, requires that the Responsible Engineer determine what surface conditions are acceptable and ensure there is no evidence of damage or degradation sufficient to warrant further evaluation or repair. Therefore, the licensee's Responsible Engineer will identify the minimum flaw size (indications of interest) required to be detected. For remote visual examinations, procedures and equipment used will be demonstrated to be capable of detecting and resolving these indications. The licensee will maintain a record of the demonstration performed.

While the use of the licensee's proposed altemative does not result in a quantitative evaluation of the illumination, it provides a method to verify that the indications of interest are visually detectable. The INEEL staff believes that samples representing these indications provide an appropriate simulation and cencludes that visual verification, via direct or remote means, of such provides sufficient evidence of adequate illumination and examination distance. Based on this, the INEEL staff believes that the licensees proposed altemative provides an acceptable level of quality and safety and should be authorized pursuant to 10 CFR 50.55a(a)(3)(i).

3. CONCLUSION The INEEL staff has evaluated the licensee's submittal for the Calvert Cliffs Nuclear Power Plant, Units 1 and 2, and concluded that for Requests for Relief E1, E2, and L1, the proposed altematives provide an acceptable level of quality and safety and should be authorized pursuant to 10 CFR 50.55a(a)(3)(i).

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