ML20237E117

Safety Evaluation Accepting Licensee Relief Requests for First 10-yr Interval Inservice Insp Nondestructive Exam Program

ML20237E117
Person / Time
Site:	Fermi
Issue date:	08/25/1998
From:	NRC (Affiliation Not Assigned)
To:
Shared Package
ML20237E113	List: ML20237E111 ML20237E117
References
NUDOCS 9808280259
Download: ML20237E117 (21)

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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION REQUESTS FOR RELIEF FOR THE FIRST 10-YEAR INTERVAL INSERVICE INSPECTION NONDESTRUCTIVE EXAMINATION PROGRAM DETROIT EDISON COMPANY FERMI 2 DOCKET NO. 50-341

1.0 INTRODUCTION

The technical specifications for Fermi 2 require that the inservice inspection (ISI) 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 Boilor and 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(6)(g)(i). 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 l or (ii) compliance with the specified requirements would recult in hardship or unusual 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 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 modPeations listed therein. The applicable edition of Section XI of the ASME Code for the Fermi 2 first 10-year ISI interval is the 1980 Edition through Winter 1981 Addenda.

By letter dated Ap-il 16,1998, as supplemented by 4 tiers dated June 19 and July 27,1998, the licensee proposed alternatives contained in requests for relief Nos. RR-A1, A16, A17, A18, A19, l A20, A21, A22, A23, and A24 for Fermi 2. The July 27,1998, letter withdrew request for relief RR-A1. This safety evaluation addresses only RR-A17, A19, A20, A21, and A22. The remaining requests for relief will be addressed in future correspondence.

9808280259 980825 PDR ADOCK 05000341 P PDR

2.0 EVALUATION The staff, with technical assistance from its contractor, the Idaho National Engineering and Environmental Laboratory, has evaluated the information provided by the licensee in support of the licensee-proposed attematives contained in requests for relief Nos. RR-A17, A19, A20, A21, and A22 for Fermi 2. Based on the results of the review, the staff adopts the contractor's conclusions and recommendations presented in its technical letter report.

2.1 Ewguealf0LBahti_BfM.11 The ASME Code, See:ior, X;, Table IWB 2500-1, Examination Category B-P, Table IWC-2500-l 1, Examination Category C-H, and Table IWD-2500-1, Examination Categories D-A, D-B and l D-C, require system hydrostatic testing of pressure-retaining components in accordance with lWA-5000 once each 10-year interval. In accordance with 10 CFR 50.55a(a)(3)(i), the licensee has proposed as an alternative to the Code requirements to use Code Case N-498-1, "Altemate Rules for 10-Year Hydrostatic Pressure Testing for Class 1,2, and 3 Systems,Section XI, Division 1."

The system hydrostatic test, as stipulated in Section XI, is not a test of the structural integrity of

. the system but rather an enhanced leakage test. Hydrostatic testing only subjects the piping i components to a small increase in pressure over the design pressure; therefore, piping dead i- weight, thermal expansion, and seismic loads present far greater challenges to the structural integrity of a system. Consequently, the Section XI hydrostatic pressure test is primarily regarded as a means to enhance leak detection during the examination of components under i pressure, rather than as a method to determine the structural integrity of the components. In addition, industry experience indicates that leaks are not being discovered as a result of hydrostatic test pressures causing a preexisting flaw to propagate through the wall, in most cases leaks are being found when the system is at normal operating pressure.

Code Case N-498, "Altemative Rules for 10-Year System Hydrostatic Testing for Class 1 and 2 Systems," was previously approved for general use on Class 1 and 2 systems in Regulatory Guide (RG) 1.147, " Inservice inspection Code Case Acceptability - ASME Section XI, Division 1," Revision 9. For Class 3 systems, Revision N-498-1 specifies requirements identical to those for Class 2 components (for Class 1 and 2 systems, the alternative requirements in N-498-1 we unchanged from N-498). In lieu of 10-year hydrostatic pressure testing at or near the end of the 10-year interval, Code Case N-498-1 requires a VT-2 visual examination at nominal operating pressure and temperature in conjunction with a system leakage test performed in accordance with paragraph IWA-5000 of the 1992 Edition of Section XI.

Class 3 systems do not normally receive the amount and/or type of nondestructive

' examinations that Class 1 and 2 systems receive. While Class 1 and 2 system failures are relatively uncommon, Class 3 leaks occur more frequently and are caused by different failure mechanisms. Based on a review of Class 3 system failures requiring repair during the last 5 years, the most common causes of failure are erosion-corrosion (EC), microbiologically induced corrosion (MIC), and general corrosion. In general, licensees have implemented programs for the prevention, detection, and evaluation of EC and MIC; therefore, Class 3 i

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systems receive inspection commensurate with their functions and expected failure mechanisms.

Considering that Code Case N-498 was found to be an acceptable attemative for Class 1 and 2 systems, and that Class 3 systems receive inspections commensurate with their function and expected failure mechanisms, the licensee's proposed attemative, to use Code Case N-498-1,

. provides an acceptable level of quality and safety. Therefore the staff concludes that the l licensee's proposed attemative is authorized pursuant to 10 CFR 50.55a(a)(3)(i). The use of this Code Case is authorized for the current interval or until such time as it is published in a future revision of RG 1.147. At that time, if the licensee intends to continue to implement Code Case N-498-1, the licensee should follow all provisions in the Code Case with limitations issued in RG 1.147, if any.

2.2 Reauest for Relief RR-A19 The ASME Code, IWA-5213 requires a holding time after pressurization to applicable test conditions before the visual examinations commence. For system hydrostatic testing of l insulated systems, a 4-hour hold time is required after attaining the test pressure and

} ' temperature conditions. For system hydrostatic testing of non-insulated components, a l 10-minute hold time is required.

I in'accordance with 10 CFR 50.55a(a)(3)(ii), the licensee proposed an alternative to the Code l hold time requirements for the insulated portions of the high-pressure coolant injection (HPCI) l- turbine / exhaust lines and associated vents and drains.

l The. Code requires a 4-hour hold time at operating pressure and temperature prior to-performing the VT-2 visual examination associated with the system hydrostatic pressure test.

6 However, maintaining the Code-required test conditions for 4-hours for the HPCI system would j result in excessive heat loads on the suppression pool and would violate plant technical specifications regarding maximum suppression pool temperature. Removal of the insulation is possible. However, as stated by the licensee, this would result in excessive radiation exposure to plant personnel and create additional radioactive waste. Therefore, imposition of the Code j hold-time requirement is a burden for the HPCI system at Fermi 2.

l As an attemative, the licensee has proposed a visual examination that will be performed l' following a 20-minute hold time, in addition, this system receives inservice testing on a quarterly basis, and 25 percent of the welds receive surface examination in accordance with the Code. The licensee's proposed altemative, in conjunction with inservice testing and the Code-required surface examinations, should detect any significant pattems of degradation and will provide reasonable assurance of the continued operational readiness of the HPCI system.

Therefore, the staff concludes that the Code-required hold time requirements would result in a burden without a compensating increase in the level of quality and safety at Fermi 2. Thus, the staff concludes that the licensee's proposed attemative is authorized pursuant to 10 CFR 50.55a(a)(3)(ii).

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2.3 Reauest for Relief RR-A20 The ASME Code,Section XI, Examination Category C-C, item C3.20, requires 100 percent surface examination, as defined by Figure IWC-2500-5, for integrally welded attachments to pipingc The licensee, in accordance with 10 CFR 50.55a(a)(3)(ii), has proposed an attemative to the Code-required surface examination for integrally welded attachments to open ended piping within the torus.

The Code requires 100 percent surface examination of the subject integral attachment welds.

However, these we!ds are located within the torus and are coated to prevent corrosion in the humid atmosphere. To perform the Code-required surface examination, the coating would have to be ground off to provide a clean surface for examination, then reapplied. Removing and reapplying the coating would require a substantial effort and would require the licensee to build scaffolding and a catch to prevent excess debris entering the pool. These activities would expose plant personnel to excessive radiation exposure. In addition, paint and dust could enter the torus pool. Imposition of this requirement would result in an undue hardship on the licensee.

As an alternative to the Code-required surface examination, the licensee has proposed to perform a remote VT-3 visual examination of the attachment welds. This attemative visual examination should detect any .significant deformation or degradation occurring at the attachment welds and provides reasonable assurance of the structuralintegrity of the subject integral attachment welds. Furthermore, later Codes (i.e.,1989 Edition) exempt open-ended piping beyond the last shutoff valve. Based on the proposed alternative examination and the i fact that the Code no longer requires examination of these welds, the staff determined that I

imposition of the Code requirements would result in an undue hardship without a compensating increase in the level of quality and safety. Therefore, the staff concluded that the licensee's

. proposed altemative is authorized pursuant to 10 CFR 50.55a(s)(3)(ii).

l 2.4 Reauest for Relief RR-A21 l The ASME Code,Section XI, Examination Category B-K-1, item B10.10, requires 100 percent l surface or volumetric examination, as defined by Figures IWB-2500-13,-14, and -15, for Class l 1 integrally welded attachments to piping whose base material is 5/8-inch and greater. In

! accordance with 10 CFR 50.55a(a)(3)(i), the licensee proposed an attemative to the Code-required examination of integrally welded attachments listed in the table below. As stated in the licensee's July 27,1998, letter, the surface examination will be supplemented by a VT-1 visual examination for each weld with limited examination coveragc.

The Code requires 100 percent surface examination of the subject integral attachment welds.

However, access to these welds to perform the Code-required surface examination is partially, or in one case, completely obstructed by clamps or lug retainers. The licensee indicated that these clamps could be removed, but the removal would result in excessive radiation exposure.

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As an alternative, the licensee proposed to perform a VT-1 visual examination to supplement the partial surface examination. The staff determined that the proposed VT-1 visual examination and associated acceptance criteria is a reasonable attemative when used to supplement the Code-required surface examination. In addition, the subject welds are part of a larger sample of integral attachment welds that are being examined to the extent required by the Code. Consequently, the staff concludes that the licensee's proposed attemative provides an acceptable level of quality and safety. The partial surface examination supplemented by a VT-1 visual examination, combined with the examination of other similar welds should detect any significant pattoms of degradation that may occur. Therefore, the staff concludes that the

. licensee's proposed attemative is authorized pursuant to 10 CFR 50.55a(a)(3)(i).

2.5 Request for Relief RR-A22 The ASME Code,Section XI, Examination Category C-C, item C3.20, requires 100 percent surface examination, as defined by Figure IWC-2500-5, for integrally welded attachments to piping, where the base metal thickness is 3/4-inch or greater.

In accordance with 10 CFR 50.55a(a)(3)(i), the licensee proposed an attemative to the Code-required surface examination for the components listed in Tcble 1 of request for relief j RR-A22. As stated in the licensee's July 27,1998, letter, a supplemental VT-1 visual

. examination will be performed for each weld.

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Table 1, RR-A22 '

ltem W Weld ID . -  % Complete i umitation C3.20 PSFW-E11-3146-606A-L 83% perlug Clamp C3.20 PSFW-E11-3146-952A-L 100% for lugs B, E, H, K, Clamp 50% for others C3.20 SW-E11-3151-4WE-4WK 90% per lug (Expected) Clamp C3.20 SW-E11-3151-10WC-10WH 90% per lug (Expected) Clamp C3.20 SW-E11-3158-583A-583F 87% per lug, lugs B & E Lug retainers C3.20 SW-E11-3158-7WC-7WH 85% per lug Clamp C3.20 PSFW-E41-3162-583A-F 90% Clamp C3.20 PSFW-E41-3172-592A-D 90 % Clamp C3.20 PSFW-E41-3172-625A-625D 80% per lug Lug retainers The Code requires 100 percent surface examination of the subject integral attachment welds.

However, access to these welds to perform the Code-required surface examination is partially obstructed by clamps or lug retainers. As stated by the licensee, these clamps could be removed, but the removal would result in excessive radiation expe,sure.

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As an attemative, the licensee proposed to perform a VT-1 visual examination to supplement the partial surface examination. The staff determined that the proposed VT-1 visual examination and associated acceptance criteria is a reasonable alternative when used to supplement the Code-required surface examination. In addition, the subject welds are part of a p larger sample of integral attachment welds that are being examined to the extent required by .

the Code. The staff concludes that the licensee's proposed attemctive provides an acceptable  !

level of quality and safety. The significant surface examination coverage, supplemented by a VT-1 visual examination and combined with the examination of other similar welds should detect any significant pattems of degradation that may occur. Therefore, the staff concludes that the licensee's proposed attemative is authorized pursuant to 10 CFR 50.55a(a)(3)(i).

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3.0 CONCLUSION

i The staff has reviewed the licensee's submittals and concludes that for requests for relief .

RR-A17, A21 and A22, the licensee's proposed alternatives to the Code requirements provide l an acceptable level of quality and safety. Therefore, the staff concludes that the licensee's l

. proposed attematives contained in these requests for relief are authorized pursuant to 10 CFR 50.55a(a)(3)(l).

For the attematives contained in requests for relief RR-A19 and A20, the staff concludes that

' the Code requirements would result in hardship without a compensating increase in the level of I quality and safety and that the altematives provide reasonable assurance of structuralintegrity of the subject components. Therefore, the staff concludes that the proposed attematives  ;

contained in these requests for relief are authorized pursuant to 10 CFR 50.55a(a)(3)(ii).  !

The attemative contained in request for relief RR-A20 (the use of Code Case N-498-1) is authorized for the current interval or until such time as the Code Case is published in a future revision of RG 1.147. At that time, if the licensee intends to continue to implement this Code Case, the licensee should follow all provisions in Code Case N-498-1 with the limitations issued in RG 1.147, if any.

I Principal Contributor: T. McLellan Date: August 25, 1998 l

Attachment:

Technical Letter Report i

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l TECHNICAL LETTER REPORT ON FIRST 10-YEAR INTERVAL INSERVICE INSPECTION REQUESTS FOR RELIEF EQB DETROIT EDISON FERMI 2 DOCKET NUMBER: 50-482 1 INTRODUCTION By letter dated April 16,1998, the licensee, Detroit Edison, submitted ten requests for relief from the requirements of the ASME Code,Section XI, for the Fermi 2, first 10-year inservice inspection (ISI) interval. The licensee requested expedited review of Request for Relief Nos. RR-A17, RR-A19, RR-A20, RR-A21 and RR-A22. In a letter dated June 19,1998, the licensee provided additional information in response to a Nuclear Regulatory Commission (NRC) request for additional information (RAI).

Additional clarification on two requests for relief was provided in a letter dated July 28,1998. The Idaho National Engineering and Environmental Laboratory (INEEL) staff's evaluation of the subject requests for relief is in the following section.

B. EVALUATION The information provided by Detroit Edison in support of these requests for relief from Code requirements has been evaluated and the bases for disposition are documented below. The Code of record for the Fermi 2, first 10-year ISI interval, which began January 1988, is the 1980 Edition through Winter 1981 Addenda of Section XI of the l ASME Boiler and Pressure Vessel Code. j 2.1 Request for Relief RR-A17, Use of Code Case N-4981, A/ ternate Rules for 10-Year Hydrostatic Pressure Testing for Class 1, 2, and 3 Systems,Section XI, Division 1 Code Requirement: Table IWB-2500-1, Examination Category B-P, Table IWC 2500-1, Examination Category C-H, and Table IWD-2500-1, Examination Categories D-A, D-B and D-C, require system hydrostatic testing of pressure-retaining components in accordance with IWA-5000 once each 10-year interval.

Licensee's Proposed Alternative: In accordance with 10 CFR 50.55a(a)(3)(i), the licensee has requested authorization to use Code Case N-498-1, Alternate Rules for 10-Year Hydrostatic Pressure Testing for Class 1, 2, and 3 Systems, Section X/,

Division 1.

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

" Pursuant to 10 CFR 50.55a(a)(3)(i), Detroit Edison is requesting relief from ASME Section XI requirements to perform the 10-year hydrostatic tests listed above.

Detroit Edison is proposing to implement the alternative of ASME Code Case N-498- l 1, The specific test configurations and test times identified in the Code Case are l 1 equivalent to the ASME Section XI requirements. Set up for the 10-year hydrostatic ]

test would be extensive and incur unnecessary dose and equipment out of service l

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l time. -Industry experience has shown that leakage is easily identified at nominal operating pressure. The Code Case is ASME approved indicating ASME Code 1 Committee members reached a consensus that the alternative will provide essentially )

l equivalent results, i.e. the reduction of test pressure to nominal operating pressure

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will not adversely affect the test intent or results. Detroit Edison agrees with the Code Committee that use of the alternative described in the Code Case will provide an acceptable level of quality and safety.

"This Code Case has also been approved for use at other nuclear utilities (e.g., Perry).

This Code Case was reviewed by the NRC as indicated in Draft Guide DG-1050 issued February 1997 and is to be approved in the next revision of Regulatory Guide l 1.147 "

t Evaluation: The Code requires a system hydrostatic test once per interval in cordance with the requirements of IWA 5000 for Class 3 pressure-retaining systems, in lieu of the Code-required hydrostatic testing, the licensee has requested authorization to use Code Case N-498-1, A/temative Rules for 10-Year System Hydrostatic Testing for Class 1, 2, and 3 Systems, dated May 11,1994.

j. The system hydrostatic test, as stipulated in Section XI, is not a test of the structural j

integrity of the system but rather an enhanced leakage test.' Hydrostatic testing only subjects the piping components to a small increase in pressure over the design pressure; therefore, piping dead weight, thermal expansion, and seismic loads present far greater challenges to the structural integrity of a system. Consequently, the l Section XI hydrostatic pressure test is primarily regarded as a means to enhance leak detection during the examination of components under pressure, rather than as a j; method to determine the structuralintegrity of the components. In addition, industry

[ experience indicates that leaks are not being discovered as a result of hydrostatic test

l. pressures causing a preexisting flaw to propagate through the wall, in most cases

! leaks are being found when the systern is at normal operating pressure.

Code Case N-498, Altemative Rules for 10-Year System Hydrostatic Testing for Class 1 and 2 Systems, was previously approved for general use on Class 1 and 2 systems

! in Regulatory Guide 1.147, Rev. 9. For Class 3 systems, Revision N-498-1 specifies requirements identical to those for Class 2 components (for Class 1 and 2 systems, the alternative requirements in N-498-1 are unchanged from N-498). In lieu of 10-year hydrostatic pressure testing at or near the end of the 10-year interval, Code l Case N-498-1 requires a VT-2 visual examination at nominal operating pressure and l temperature in conjunction with a s/ stem leakage test performed in accordance with j l

paragraph IWA-5000 of the 1992 Edition of Section XI.

Class 3 systems do not normally receive the amount and/or type of nondestructive examinations that Class 1 and 2 systems receive. While Class 1 and 2 system l

S. H. Bush and R. R. Maccary, " Development ofIn-Service Inspection Safety

' Philosophy for U.S.A. Nuclear Power Plants," ASME,1971 l

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failures are relatively uncommon, Class 3 leaks occur more frequently and are caused by different failure mechanisms. Based on a review of Class 3 system failures requiring repair during the last 5 years,2 the most common causes of failure are l

erosion-corrosion (EC), microbiologically induced corrosion (MIC), and general corrosion, in general, licensees have implemented programs for the prevention, detection, and evaluation of EC and MIC; therefore, Class 3 systems receive inspection commensurate with their functions and expected failure mechanisms.

4 Considering that Code Case N-498 was found to be an acceptable alternative for Class 1 and 2 systems, and that Class 3 systems receive inspections commensurate

. with their function and expected failure mechanisms, the licensee's proposed alternative, to use Code Case N-498-1, should provide an acceptable level of quality and safety. Therefore it is recommended that the licensee's proposed alternative be j authorized pursuant to 10 CFR 50.55a(a)(3)(i). The use of this Code Case should be authorized for the current interval or until such time as it is published in a future i revision of Regulatory Guide 1.147. At that time, if the licensee intends to continue to implement Code Case N-498-1, the licensee should follow all provisions in the Code Case with limitations issued in Regulatory Guide 1.147, if any.

l 2.2 Request for Relief RR-A19, IWA 5213, Test Condition Holding Time

' Code Requirement: IWA 5213 requires holding time after pressurization to applicable l test conditions, before the visual examinations commence. For system hydrostatic testing of insulated systems, a 4-hour hold time is required after attaining the test pressure and temperature conditions. For system hydrostatic testing of non-insulated f components, a 10-minute hold time is required.

L Licensee's Proposed Alternative: In accordance with 10 CFR 50.55a(a)(3)(ii), the licensee proposed an alternative to the Code hold time requirements for the insulated portions of the HPCI turbine / exhaust lines and associated vents and drains. The l ' licensee stated:

"The system pressure test described in Code Case N-498 will be conducted as required, except that a 20 minute hold time will be used in lieu of the 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> hold time requirement. The 20 minute hold time will allow time for abnormalleaks to migrate through the insulation without challenging the Technical Specification limitation on maximum torus water temperature.

I-l Licensee's Basis for Proposed Alternative (as stated):

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( "As part of the Emergency Core Cooling System (ECCS), the HPCI system is not Documented in Licensee Event Reports and the Nuclear Plant Reliability Data System databases.

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required to operate during normal plant operation. However, the system is periodically tested in accordance with applicable inservice testing and Technical l Specification requirements. These periodic tests are conducted to verify the operability of system components. The quarterly Operability test (24.202.001) normally includes about 30 minutes of pump run time, in order to satisfy ASME Section XI hold time requirement, the test would require a HPCI pump run for greater than 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> (hold time plus exam time). Running the HPCI pump for this duration is not practical and represents an undue hardship on the facility without a compensating increase in the level of quality and safety.

" Operating the HPCI pump for this amount of time would subject the facility to excessive heat loads. Control of these heat loads would require the operation of additional ECCS subsystems to remove heat from the suppression pool.

" Extended operation of the HPCI pump would also challenge the Technical Specification limitation on maximum suppression pool (torus) water temperature. The Fermi Technical Specifications require the torus average water temperature to be maintained less than 105'F during testing which adds heat to the torus. Operating the HPCI pump for a period substantially longer than the system operability test could

< cause this temperature to be exceeded. If the torus average water temperature I

exceeds 110 'F, Technical Specifications require the reactor mode switch to be placed in the shutdown position.

" Removal of the insulation from the subject components in order to use the ten

! minute hold time allowed by the Code or Code Case N-498, would be equally burdensome. The impacts associated with insulation removal and reinstallation,

!' include, personnel radiation exposure, radweste generation, manpower resource, and

monetary costs, are not justified by a compensating increase in the level of quality and safety.

" Performing a HPCI system hydrostatic test per IWA-5213(d) would also be burdensome. A hydrostatic test would required installation of blank flanges and

( ' temporary pipe supports, and gagging or removal of relief valves. The time, costs and radiation exposure incurred in carrying out a hydrostatic test would result in a hardship without a compensating increase in the level of quality and safety.

"Other inspection and test activities performed that verify system integrity include the following:

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• Quarterly inservice testing of HPCI raises the pressure of the system to nominal l: operating conditions. Any leakage would migrate through the insulation over a period of time an would become evident.

o - Nondestructive examination of 25% or 14 of the circumferential welds on this line receive a surface examination per Section XI Table IWB-25001, Category C-F. All of the weld selections on this line were random selections because none of the welds met the moderate or high stress criteria.

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Every 18 months this line is inspected in accordance with the Fermi Leakage Reduction Program per Technical Specification 6.8.5."

Evaluation: The Code requires a 4-hour hold time at operating pressure and temperature prior to performing the VT 2 visual examination associated with the system hydrostatic pressure test. However, maintaining the Code-required test conditions for 4-hours for the HPCI system would result in excessive heat loads on the suppression pool and would violate plant technical specifications regarding maximum suppression pool temperature. Removal of the insulation is possible.

However, as stated by the licensee, this would result in excess radiation exposure to plant personnel and create additional radwaste. Therefore, imposition of the Code hold-time requirement is a burden for th'e HPCI system at Fermi 2.

As an attemative, the licensee has proposed a visual examination that will be performed following a 20 minute hold time. In addition, this system receives inservice testing on a quarterly basis, and 25% of the welds receive surface examination in accordance with the Code. The licensee's proposed alternative, in conjunction with inservice testing and the Code-required surface examinations should detect any significant patterns of' degradation, and will provide reasonable assurance of the continued' operational teadiness of the HPCI system. Therefore, it is concluded that the Code-required hold time requirements would result in a burden without a compensating increase in the level of quality and safety at Fermi 2. It is also recommended that the licensee's proposed alternative be authorized pursuant to 10

- CFR 50.55a(a)(3)(ii).

2.3 Request for Relief RR-A20, Examination Category C-C, item C3.20, Integrally Welded l

l Attachments to Open Ended Piping Within the Torus i

Code Requirement: Examination Category C-C, item C3.20, requires 100% surface examination, as defined by Figure IWC-2500-5, for integrally welded attachments to piping.

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Licensee's Proposed Alternative: In accordance with 10 CFR 50.55a(a)(3)(ii), the

' licensee proposed an alternative to the Code required surface examination for )

integrally welded attachments to open ended piping withing the torus. The licensee )

stated:

" Fermi proposes to examine the external portion of the piping attachment, and perform remote VT-3 examination to the extent practical on the internal portion from the catwalk using binoculars. This alternative is more conservative than current Code requirements; therefore, it provides an acceptable level of quality and safety."

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

" Pursuant to 10 CFR 50.55a(a)(3)(ii), Detroit Edison is requesting relief from ASME Section XI requirements to perform a surface examination of torus internal piping integrally' welded attachments that have a base rnetal design thickness of 3/4" or ,

greater. The Fermi design includes torus stiffener pads and gusset plates which are {

welded to the system piping that penetrates the torus. Because of the base metal i thickness (> 3/4") these welds require a surface examination.

"The interior surfaces of the torus are coated to prevent corrosion of surfaces which

are exposed to the humid atmosphere. Performing a magnetic particle examination of the torus stiffener pads and gusset welds would required this coating to be ground .

off and reapplied after the examinations were complete. Grinding off the coating to allow a proper examination takes a substantial amount of time and the grinding process could result in paint chips and dust entering the torus pool. The humidity could also have a negative impact on examination performance as surface condensation would restrict particle movement.

I "The penetrations are over water surface and are not accessible from the cat walk.

Gaining accessibility to the penetrations would require a suspended scaffold to be built and a catch hung to prevent debris entry into the torus pool. Craft personnel have estimated that it would take six laborers three shifts per location to build this type of structure. Performance of this work would not be consistent with good ALARA practices.

"Both the subject piping systems are open ended to the torus. The ASME Section XI 1989 Edition currently approved by the NRC and incorporated into 10 CFR 50.55a by

reference and later Editions through the 1995 Edition pending NRC approval, provide

f. exemption from examination for open ended piping beyond the last shutoff valve (IWC-1220) ' When Fermi completes the required program update these welds will no longer require examination.

"These penetrations also have integral attachments on the torus external surface that require examination per the 1980 Edition of ASME Section XI. Examination of these external attachment welds would indicate any damage to the piping system at the 6

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penetrations that would prevent the fluid from reaching the torus.

" Performance of these exams presents an undue hardship without a compensating increase in the level of quality and safety."

Evaluation: The Code requires 100% surface examination of the subject integral attachment welds. However, these welds are located within the torus and are coated to prevent corrosion in the humid atmosphere. To perform the Code-required surface examination, the coating would have to be ground off to provide a clean surface for examination, then reapplied. Removing and reapplying the coating would require a substantial effort and would expose plant personnel to excessive radiation exposure. In addition, paint and dust could enter the torus pool without building scaffolding and a catch to prevent excess debris entering the pool. Imposition of this requirement would result in an undue hardship on the licensee.

As an alternative to the Code-required surface examination, the licensee has proposed to perform a remote VT-3 visual examination of the attachment welds.

This a!!ernative visual examination should detect any significant deformation of degradation occurring at the attachment welds and provides reasonable assurance of the structural integrity of the subject integral attachment welds. Furthermore, later Codes (i.e.,1989 Edition) exempt open-ended piping beyond the last shutoff valve.

Based on the proposed alternative examination and the fact that the Code no longer requires examination of these welds, it is concluded that imposition' of the Code requirements would result in an undue hardship without a compensating increase in the level of quality and safety. Therefore, it is recommended that the licensee's proposed alternative be authorized pursuant to 10 CFR 50.55a(a)(3)(ii).

2.4 Request for Relief RR-A21, Examination Category B-K-1, Item B10.10, Integrally Welded Attachments to Piping Code Requirement: Examination Category B-K-1, item B10.10, requires 100%

I- surface or volumetric examination, as defined by Figures IWB-2500-13, -14 and -15 for Class 1 integrally welded attachments to piping whose base material is 5/8-inch 7 ,

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and greater.

Licensee's Proposed Alternative: In accordance with 10 CFR 50.55a(a)(3)(i), the licensee proposed an alternative to the Code-required examination of integrally welded attachments listed in the table below. As stated in the licensee's letter dated

. July 27,1998, the surface examination will be supplemented by a VT-1 visual examination for each weld with limited examination coverage. The licensee stated:

" Detroit Edison proposes that in addition to the surface examination of the exposed portion of lug welds and required base metal volume, that a supplemental visual examination to the extent practical by the examiner be performed. Additionally, leakage inspection are performed at the completion of each refueling outage per Category B-P.

" Based on the coverage achievable, physical limitations, comparison of Fermi ISI Program scope as compared to current Code requirements, and low empirical probability of weld failure, Detroit Edison considers the proposed alternative examination to provide an acceptable level of quality and safety.

Table RR-A211 ~ 1. . N-: m.

% Completed ' ,

~

Wold ID) '

Limitation $

• FW PS-B2-AA1-AA4 70% (Expected) Clamp FW-PS 2-D2 AA1-AA4 70 % Clamp FW-RD-2-A2 AL1-AL4 68% Clamp FW-RD-2 B2-AL1-AL4 68% (Expected) . Clamp SW RS 2 A2 W4-W7 68% (Expected) Clamp l SW RS-2-B2 W6A-W9A 68 % Clamp PSFW E11-2298-833A-F 69% per lug Clamp PSFW E112299-836A-F 50% per lug (Expected) Clamp PSFW-E11-2299-781 A-D 50% per lug Clamp SW-E11-2327-2WD-2WJ 90% per lug Clamp SW-E21-3052 .2WN-2WR 88% per lug Clamp PSFW-E21-3052-803A-D 84% per lug Clamp SW-E21-3053-2WN-2WR 86% per lug Clamp 8

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SW-E21-3052-2WS-2WV 88% per lug (Expected) Clamp

.SW E21-3053 2WS-2WV 69% per lug Clamp i

SW-E21-3053-795A-795D 88% per lug Clamp SW-N21-233612WC-12WH 86% per lug Clamp I SW-N21-2336-12WJ 12WP 66% per lug Clamp SW-N21 2336-19WB-19WE 0% per lug inaccessible for MT due to lug retainers SW-N21-2336-9WB-9WE 90% per lug Clamp SW N212336-2WC-2WN 90% per lug Clamp l

Licensee's Basis for Proposed Alternative (as stated)- i

" Pursuant to 10 CFR 50.55a(a)(3)(i), Detroit Edison is requesting relief from ASME l Section XI requirements to perform complete (>90%) surface examination of all  !

integrally welded attachments that have a base metal design thickness of 5/8" or greater.

"The proposed alternative is partial nondestructive examination supplemented by visual examination. Technical justification for the adequacy of the alternative is substantiated by changes in the ASME Code, "The relief request also identified burdens associated with engineering resource impacts, clamp removal, location restoration, which would represent a burden to '

existing resources. Identification of these burdens are provided only in support of the ,

, need for an alternative. The engineering resources impacts mentioned are incurred in '

diverting limited engineering resources away from other tasks.

"The structuralintegrity of the piping pressure boundary including welded attachments was originally demonstrated during construction by meeting the requirements of ASME Section 111. Design, fabrication, installation, inspection, and examination satisfied the appropriate Code requirements. Construction examinations  !

used techniques similar to those used for inservice examinations (surface NDE methods). During the Fermi Preservice inspection volumetric examinations were also performed. The construction and preservice examinations were usually completed prior to installation of the support members. Therefore, the extent of accessibility is

< not specifically known until the first inservice examination is completed. Integral attachment locations remaining to be examined were compared to locations similar in dasign and any expected limitations are listed in the table.

"The pressure boundary passed the required preservice hydrostatic test and all l subsequent pressure tests through the fifth refueling and inspection outage (RF-05). l l

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" Complete examinations meeting the coverage requirements of ASME Code Section XI are performed on welds of similar configurations which utilized the same weld techniques, procedures and materials. The welds with complete examinations are spread throughout the Class 1 systems and subject to similar operating and environmental conditions as the partially examined welds. No service related discontinuities have been discovered on welds fully examined or those partially examined. Additionally, there is no industry history of ASME Class 1 service induced attachment weld failures. It is reasonable to expect that the unexarrined portions are also acceptable.

"The absence of significant integra! attachment weld problems is further evidence by ASME Code Case N-509 which allows a reduced sample size of only 10% of all integral attachments. This Code Case has been approved at other nuclear facilities (e.g., Duane Arnold) and was incorporated into the 1995 Addenda of ASME Section XI. Detroit Edison has not requested to implement this Code Casa, which would reduce the inspection population to approximately 10 locations, during our first inspection interval. We are only requesting partial relief of coverage on specific locations included in the 29 locations where examinations can be performed.

"The average surface coverage for the incomplete examinations completed and listed

- in Table 1 [ Table RR A21] is 73%. To obtain complete Code coverage at each location, the component support would have to be disassembled and the pipe clamp assembly removed. Temporary line support would have to be evaluated by engineering and installed as necessary. The additional engineering resources, time, field personnel, and radiation exposure required to attain full coverage is not consistent with the minimal risk associated with these items, as reflected by plant and industry experience as well as current Code requirements.

" Radiation exposure for a best case location assuming a conservative effective j (averaged) dose rate of Smr/hr and a minimum of 16 man-hours to remove and  !

reinstall the clamp assembly and inspect the location would result in at least 80mr additional exposure per location (approximately 1.7R minimum accumulated dose).

Note that this assumption uses and effective averaged dose rate, and actual dose on a pipe is often much higher. Removal of the clamps could actually increase the .

possibility of damaging other components such as nozzles and penetrations due to )

additional line stress. Additionally, the time for disassembly and reassembly does not I assume mechanical difficulties such as temporary line support, seized bolts, and removal and reinstallation of welded lug retainers from the clamps, that will greatly increase the time and dose impacts."

Evaluation: The Code requires 100% surface examination of the subject integral i

attachment welds. However, access to these welds to perform the Code-required surface examination is partially, or in one case, completely obstructed b/ clamps or j i

lug retainers. As stated by the licensee, these clamps could be removed, but the  !

removal would result in excess radiation exposure.

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As an alternative, the licensee proposed to perform a VT-1 visual examination to supplement the partial surface examination. The INEEL staff believes that the proposed VT-1 visual examination and associated acceptance criteria is a reasonable alternative when used to supplement the Code-required surface examination. In addition, the subject welds are part of a larger sample of integral attachment welds that are being examined to the extent required by the Code. Consequently, it is concluded that the licensee's proposed alternative provides an acceptable level of quality and safety. The partial surface examination supplemented by a VT-1 visual examination, combined with the examination of other similar welds should detect any significant patterns of degradation that may occur. Therefore, it is recommended l

that the proposed alternative be authorized pursuant to 10 CFR 50.55a(a)(3)(i).

i 2.5. Request for Relief RR A22, Examination Category C-C, item C3.20, Integrally Welded Attachments to Piping Code Requirement: Examination Category C-C, item C3.20, requires 100% surface 1

examination, as defined by Figure IWC-2500-5, for integrally welded attachments to l piping, where the base metal thickness is 3/4-inch or greater.

Licensee's Proposed Alternative: In accordance with 10 CFR 50.55a(a)(3)(i), the licensee proposed an alternative to the Code-required surface examination for the components listed in Table RR-A22. As stated by the licensee, a supplemental VT-1 visual examination will be performed for each weld. The licensee stated:

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" Detroit Edison proposes that in addition to the surface examination of the exposed portion of lug welds and required base metal volume, that a supplemental visual

examination to the extent practical by the examiner be performed. Additionally, leakage inspection are. performed at the completion of each refueling outage per Category C H.

I

" Based on the coverage achievable, physical limitations, comparison of Fermi ISI Program scope as compared to current Code requirements, and low empirical probability of weld failure, Detroit Edison considers the proposed alternative examination to provide an acceptable level of qua!ity and safety.

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l L Table RR-A22'

. Item # i  : Wold'lDl _ % Complete - , ' Limitation C3.20 PSFW-E11-3146-606A-L 83% per lug Clamp C3.20 PSFW E11-3146-952A-L 100% Lugs B, E, H. K Clamp 50% for Others C3.20 SW-E11-3151-4WE-4WK 90% per lug (Expected) Clamp L C3.20 SW-E11-3151-10WC-10WH 90% per lug (Expected) Clamp ,

C3.20 SW-E11-3158-583A-583F 87% per lug, lugs A & B Lug retainers 4

C3.20 SW-E11-3158-7WC-7WH 85% per lug Clamp )

-l C3.20 PSFW-E41-3162 583A-F 90 % Clamp

]

(.

C3.20 PSFW-E41-3172-592A-D 90 % Clamp C3.20 PSFW-E41-3172 625A-625D 80% per lug Lug retainers q Licensee's Basis for Proposed Alternative (as stated):

" Pursuant to 10 CFR 50.55s(a)(3)(i), Detroit Edison is requesting relief from ASME ,

Section XI requirements to perform complete (> 90%) surface examination of all integrally welded attachments that have a base metal design thickness of 3/4" or greater.

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"The proposed alternative for Fermi is partial nondestructive examination supplemented by visual examination. Technical justification for the adequacy of the alternative is substantiated by changes in the ASME Code.

"The relief request also identified burdens associated with engineering recource impacts, clamp removal, location restoration, which would represent a burden to _q existing resources. Identification of these burdens are provided only in support of the I need for an alternative. The engineering resources impacts mentioned are incurred in L diverting limited engineering resources away from other tasks.

i "The structuralintegrity of the piping pressure boundary including welded ,

L attachments was originally demonstrated during construction by meeting the 1 requirements of ASME Section Ill. Design, fabrication, installation, inspection, and examination satisfied the appropriate Code requirements. Construction examinations used techniques similar to those used for inservice examinations (surface NDE methods). During the Fermi Preservice inspection volumetric examinations were also l l'

performed. The construction and preservice examinations were usually completed prior to installation 'of the support members. Therefore, the extent of accessibility is 1 not specifically known until the first inservice examination is completed. Integral '

attachment locations remaining to be examined were compared to locations similar in .

design and any expected limitations are listed in the' table.

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L_______________________________________________________________ _ _ _ _ _ _ _ _ _ _ _ _ _ ..__ _ _ _ _ _ _ _ _ _ _ _ _ _ .. _ _ _ _ _ _ _ _ _ _ _ _

.a . ,

(

-e "The pressure boundary passed the required preservice hydrostatic test and all subsequent pressu're tests through the fifth refueling and inspection outage (RF-05),

l- " Complete examinations meeting the coverage requirements of ASME Code Section.

l XI are performed on welds of similar configurations which utilized the same weld techniques, procedures and materials. The welds with complete examinations are j~ subject to similar operating and environmental conditions as the partially examined j' welds. No service related discontinuities have been discovered on welds fuity

l. examined or those partially examined. Additionally, there is no industry history of ASME Class 2 service induced attachment weld failures. It is reasonable to expect that the unexamined portions are also acceptable.

"The absence of significant integral attachment weld problems is further evidence by

ASME Code Case N-509 which allows a reduced sample size of only 10% of all integral attachments. This Code Case has been approved at other nuclear facilities (e.g., Duane Arnold) and was incorporated into the 1995 Addenda of ASME Section XI. ' Fermi has not requested to implement this Code Case, which would reduce the inspection population to approximately 19 locations, during our first inspection interval. We are only requesting partial relief of coverage on specific locations included in the 39 locations where examinations can be performed.

"The average surface coverage for the incomplete examinations completed and listed in Table 1 [ Table P.R-A22] is 87%. To obtain complete Code coverage at each location, the component support would have to be disassembled and the pipe clamp assembly removed. Temporary line support would have to be evaluated by engineering and installed as necessary. The additional engineering resources, time,

, field personnel, and radiation exposure required to attain full coverage is not

! consistent with the minimal risk associated with these items, as reflected by plant

! and industry experience as well as current Code requirements.

" Radiation exposure for a best case location assuming a conservative effective (averaged) dose rate of 5mr/hr and a minimum of 16 man-hours to remove and

[- reinstall the clamp assembly and inspect the location would result in at least 80mr f additional exposure per location (approximately 640mr minimum accumulated dose).

Note that this assumption uses and effective averaged dose rate, and actual dos.e on a pipe is often much higher. Removal of the clamps could actually increase the possibility of damaging other componunts such as nozzles and penetrations due to

!' additional line stress. Additionally, the time for disassembly and reassembly does not assume mechanical difficulties such as temporary line support, seized bolts, and removal and reinstallation of welded lug retainers from the clamps, that will greatly increase the time and dose impacts."

Evaluation: The Code requires 100% surface examination of the subject integral attachment welds. However, access to these welds to perform the Code-required surface examination is partially obstructed by clamps or lug retainers. As stated by 13

i a

the licensee, these clamps could be removed, but the removal would result in excess radiation exposure.

l As an alternative, the licensee proposed to perform a VT-1 visual examination to l supplement the partial surface examination. The INEEL staff believes that the proposed VT-1 visual examination and associated acceptance criteria is a reasonable alternative when used to supplement the Code-required surface examination. In I

addition, the subject welds are part of a larger sample of integral attachment welds that are being examined to the extent required by the Code. Consequently, it is concluded that the licensee's proposed alternative provides an acceptable level of quality and safety. The significant surface examination coverage, supplemented by a j i i VT-1 visual examination and combined with the examination of other similar welds should detect any significant patterns of degradation that may occur. Therefore, it i is recommended that the proposed alternative be authorized pursuant to 10 CFR l' BO.55a(a)(3)(i).

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3.0 CONCLUSION

i The INEEL staff has reviewed the licensee's submittals and concludes that for Requests l'

for Relief RR-A17, RR-A21 and RR-A22, the licensee's proposed alternatives to the Code requirements provide an acceptable level of quality and safety. Therefore, it is ,

l recommended that these proposed alternatives be authorized pursuant to 10 CFR 50.55a(a)(3)(i). For Request for Relief RR-A19 and RR-A20, it is concluded that the Code requirements would result in hardship without a compensating increase in the  ;

t l level of quality and safety. Therefore, it is recommended that these proposed alternatives be authorized pursuant to 10 CFR 50.55a(a)(3)(ii).

For Request for Relief RR-A20, the use of Code Case N-498-1 should be authorized for the current interval or until such time as the Code Case is published in a future revision i

.14 u__

e of Regulatory Guide 1.147. At that time, if the licensee intends to continue to implement this Code Case, the licensee should follow all provisions in Code Case l N-498-1 with limitations issued in Regulatory Guide 1.147, if any.

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