ML20034G496

Safety Evaluation Concluding That Rev 3 to First 10-yr ISI Program Summary Rept Unacceptable & Not in Compliance W/Regulations.Listed Requests for Relief Granted.Certain Requests Denied

ML20034G496
Person / Time
Site:	Millstone
Issue date:	03/03/1993
From:	Office of Nuclear Reactor Regulation
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ML20034G495	List: ML20034G494 ML20034G496
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NUDOCS 9303090602
Download: ML20034G496 (13)

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UNITED STATES y

g NUCLEAR REGULATORY COMMISSION E

W ASHINGTON, D. C. 20555 g

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'S9.....,o SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION OF THE FIRST TEN-YEAR INTERVAL INSERVICE INSPECTION PROGRAM

SUMMARY

REPORT. REVISION 3. AND RE0 VESTS FOR REllEF FACILITY OPERATING LICENSE NO. NPF-49 NORTHEAST NUCLEAR ENERGY COMPANY MILLSTONE NUCLEAR POWER STATION. UNIT NO. 3 DOCKET NUMBER 50-423

1.0 INTRODUCTION

Technical Specification 3/4.0.5 for Millstone Nuclear Power Station, Unit No. 3, states that the Inservice Inspection and Testing 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 Code and applicable Addenda as required by 10 CFR 50.55a(g), except where specific written relief has been granted by the Commission pursuant to 10 CFR 50.55a(g)(6)(i).

The Code of Federal Regulations at 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 difficulties without a compensating increase in the level of quality and safety.

Pursuant to 10 CFR 50.55a(g)(4), ASME Code Class 1,

.d 3 components (including supports) shall meet the requirements, except the design and access provisions and the preservice 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 reouire that ir. service examination of components and system pressure tests conducted during the first 10-year interval comply with the requirements in the )itest edition and addenda of Section XI of the ASME Code incorporated by reference in 10 CFR 50.55a(b) on the date 12 months prior to the date of issuance of the operating license, subject to the limitations and modifications listed therein. The applicable edition of Section XI of the ASME Code for the Millstone, Unit 3, first 10-year inservice inspection (ISI) interval is the 1983 Edition, through Summer 1983 Addenda.

The components (including supports) may meet the requirements set forth in subsequent editions and addenda of the ASME Code incorporated by reference in 10 CFR 50.55a(b) subject to the limitations and modifications listed therein.

i 9303090602 930303 PDR ADDCK 05000423 O

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. Pursuant to 10 CFR 50.55a(g)(5), if the licensee determines that conformance I

with an examination requirement of Section XI of the ASME Code is not practical for its facility, information shall be submitted to the Commission i

in support of that determination and a request made for relief from the ASME Code requirement.

After evaluation of the determination, pursuant to 10 CFR 50.55a(g)(6)(i), the Commission may grant relief and may impose

'l alternative requirements that are determined to be authorized by law, will not i

endanger life, property, or the common defense and security, and are otherwise in the public interest, giving due consideration to the burden upon the licensee that could result if the requirements were imposed, i

Northeast Nuclear Energy Company, the licensee, submitted the Millstone, Unit 3, first 10-year interval inservice inspection Program Summary Report, l

Revision 3, in a letter dated October 30, 1991. This submittal includes

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requests for relief from ASME Section XI requirements that the licensee has a

determined to be impractical for its facility. As a result of a conference a

call on April 13, 1992, the licensee submitted additional information regarding the first 10-year ISI program in a letter dated June 1,1992. A letter dated May 4, 1989, submitted by the licensee, the Hillstone, Unit 3, first 10-year interval inservice inspection Program Summary Report, Revision 2 was also used as a reference by the staff in this review.

i 2.0 EVALUATION The staff, with technical assistance from its Contractor, the Idaho National Engineering Laboratory (INEL), has evaluated the information provided by the licensee in Revision 3 of the ISI Program Summary Report and in support of the requests for relief as follows.

2 A.

Evaluation of Millstone Nuclear Power Station. Unit 3. First Ten Year Procram Summary Report. Revision 3 3

1.

Previous Program Deficiencies: Revision 1 of the Millstone, Unit 3, first interval ISI program was evaluated in a Technical Evaluation Report (TER) i and Safety Evaluation (SE) dated February 8, 1992. These documents cited three deficiencies that are addressed by the licensee in Revision 3 of the Program Summary as follows:

l 1

a.

In the NRC SE cited above, it was recommended that the licensee either

1) use the 1974 Summer 1975 Codc Edition and Addenda for selection of welds examined in Class 2 Residual Heat Removal (RHR), Emergency Core Cooling (ECC), and Containment Heat Removal (CHR) systems as required by 10 CFR 50.55a(b)(iv), or 2) request permission to update examination requirements of all Class 2 piping welds to the 1983 Edition, Winter 1985 Addenda (83W85), or the 1986 Edition, per 10 CFR 50.55a(g)(4)(iv).

In i

response to the staff recommendations, the program was upgraded in Revision 3 to meet the requirements of the 83W85 Code for Class 2, Examination Category C-F-1 and C-F-2 piping welds. However, review of Revision 3 shows that the Chemical and Volume Control System (CHS) containing 129 welds, and the High Pressure Safety Injection System (SIH) 1

- containing 96 welds have been completely excluded from examination. This l

1s not acceptable.

Paragraph 10 CFR 50.55a(b)(2)(iv) requires that ASME Code Class 2 piping welds in the RHR, ECC, and CHR systems must be examined. These systems may not be completely excluded from volumetric examinations based on wall thickness. The staff has previously determined for similar plants that a 7.5% augmented volumetric examination of these i

systems constitutes an acceptable sample size. Therefore, the ISI Program

)

Plan should be revised to include volumetric examination of 7.5% of welds 1

in the CHS and the SIH systems.

b.

Revision 1 of the ISI Program contained insufficient information on hydrostatic testing pressure boundaries for Class 1, 2, and 3 systems. A section addressing pressure boundaries for the hydrostatic testing of Class 1, 2, and 3 components is included in Revision 3 of the ISI Program Summary.

c.

Revision I did not provide adequate information on the method of compliance with the examination scheduling requirements of Paragraphs IWB-2412-1 and IWC-2412-1.

Compliance with the scheduling requirements of IWB-2412-1 and IWL.-2412-1 is listed by Examination Category in Table G of Revision 3 of the ISI Program Summary.

l l

2.

Referenced Code Cases:

The Millstone, Unit 3 Program Summary Report, l

Revision 3 references six code cases in Section 1.1.1.

Four of the code cases, N-436-1, N-437, N-460, and N-461 are referenced in NRC Regulatory Guide 1.147, Revision 9 and are acceptable for general use. The two remaining code cases, N-323 and N-495 from Section 1.1.1, and an additional Code Case N-307, which is referenced in Section 5.1.2.1 and j

also in Request for Relief IR-17, are not approved for general use by reference in NRC Regulatory Guide 1.147. These unapproved code cases are discussed below.

Code Case N-323, " Alternative Examinations for Integrally Welded Attachments to Vessels,Section XI, Division 1," has been found acceptable for use at Millstone, Unit 3, as discussed in the evaluation of Request for Relief No. IR-6 (Section D of this report).

Code Case N-495, " Hydrostatic Testing of Relief Valves,Section XI, Division 1," applies to relief valves that have been removed and not subjected to a system hy.irostatic test. A related Code Case, N-498,

" Alternative Rules for 10-Year Hydrostatic Pressure Testing for Class 1 and 2 Systems,Section XI, Division 1," has recently been approved for general use by incorporation into Regulatory Guide 1.147, Revisior. 9.

Code Case N-498 provides alternative rules for 10-Year Hydrostatic testing for Class 1 and 2 systems.

In regard to this related Code Case, the staff concludes that the alternative rules of Code Case N-495 will provide adequate assurance of the integrity of relief valves, therefore, approves the use of Code. Case N-495 at Millstone, Unit 3.

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. Code Case N-307, " Revised Ultrasonic Examination Volume for Class 1 Bolting, Examination Category B-G-1,Section XI, Division 1, When the Examinations Are Conducted from the Center Drilled Hole," has been found unacceptable for use at Millstone, Unit 3, as discussed in the evaluation of Request for Relief No. IR-17 (Section J of this report).

B.

Recuest for Relief No. IR-1. Revision 3. Examination Cateaory B-A. Items Bl.12 and 81.21. Reactor Pressure Vessel (RPV) Lonaitudinal Shell and Circumferential Head Welds Code Recuirement:

Table IWB-2500-1, Examination Category B-A, Items Bl.12 and B1.21 require 100% volumetric examinations of RPV longitudinal shell welds and circumferential head welds as defined by Figures IWB-2500-2 and IWB-2500-3, respectively.

Licensee's Code Relief Recuest:

Relief is requested from performing the volumetric examinations of RPV Shell-to-Lower Head Weld #4 and Upper Shell Longitudinal Welds #6, #7, and #8, to the extent required by the Code.

Licensee's Basis for Recuestina Relief:

Geometric configuration and permanent obstructions prevent 100% of the Code-required volumetric examination from being performed. These welds received both volumetric (radiography) and surface examinations during fabrication, in accordance with ASME Section III requirements, which provide adequate assurance of the structural integrity of the welds.

Specific obstructions and limitations for each weld are as follows:

Lower Shell-to-Lower Head Weld #4: This weld is 100% accessible from the lower head side and in both circumferential directions, but is obstructed by six core lugs from the lower shell side of the weld where coverage is limited to 70% of the required weld volume.

Upper Shell Longitudinal Welds #6, #7, and #8:

Examination limited to 37% of weld #6 and 47% of welds #7 and #8 due to nozzle geometry. These examinations will be performed to the maximum extent practical at the end of the first 10-year interval.

Licensee's Proposed Alternative Examination: None. The Code-required volumetric examinations will be performed to the maximum extent practical.

Staff Evaluation: The Code requires that the subject welds receive a 100%

volumetric examination. However, permanent obstructions exist that preclude volumetric examination to the extent required by the Code.

Therefore, the Code requirement is impractical.

In order to perform the examination to the extent required by the Code, the RPV would require extensive design modifications and rework.

Impusition of the requirement on the Licensee would cause a burden that would not be compensated by an increase in quality and safety above that provided by the limited examination. The limited

0

examination does include a significant percentage of the required weld volume, thus the structural integrity of the RPV will be assured.

Pursuant to 10 CFR 50.55a(g)(6)(1), relief is granted as requested.

C.

Recuest for Relief No. IR-2 (Revision 2). Examination Catecory B-A.

Items B1.22 and Bl.40. RPV Meridional Head and Head-to-Flance Welds Code Reauirement:

Table IWB-2500-1, Examination Category B-A, Items Bl.22 and B1.40 require 100% volumetric examinations of RPV welds as defined by IWB-2500-4 (meridional head welds) and IWB-2500-5 (head-to-flange weld).

Licensee's Code Relief Reauest:

Relief is requested from performing the volumetric examinations to the extent required by the Code for Head-to-Flange Weld #101-101 and Meridional Head Weld #101-104D.

Licensee's Basis for Reauestino Relief: Geometric configuration and permanent obstructions limit performance of the volumetric examination. Access to the head-to-flange weld is limited to one side (the top side) due to the forged flange configuration.

In addition, access from the top is limited due to the permanently attached head lifting lugs. Approximately 62% of the required volume can be examined.

Access to the meridional head weld is limited due to the surface concavity of a 2.7 inch diameter repair area. Approximately 98% of this weld can be inspected.

Licensee's Proposed Alternative Examination: None. The Code-required volumetric examination will be performed to the extent practical.

Staff Evaluation:

The subject welds were included in a relief request that-was previously granted in an NRC SER dated February 8, 1991.

Since the technical content of the request has not changed, the conclusions from the previous SER are still applicable. Therefore, pursuant to 10 CFR 50.55a(g)(6)(i), relief is granted as requested for Weld #101-101.

Relief is not required for Weld #101-104D since essentially 100% (98%) of the weld is examinable.

D.

Reouest for Relief No. IR-6. Examination Catecory B-H. Item B8.20.

Pressurizer IntecrallY Welded Attachments Code Recuirement:

Table IWB-2500-1, Examination Category B-H, Item B8.20 requires either a 100% volumetric or a 100% surface examination of pressurizer integrally welded attachments, as defined by Figures IWB-2500-13, -14, or -15 (as applicable).

Licensee's Code Relief Recuest:

Relief is requested from performing the Code-required surface examination on inaccessible portions of pressurizer support skirt-to-shell Weld 03-0070SW-X. The inaccessible portion corresponds to surface C-D in Figure IWB-2500-13.

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Licensee's Prooosed Alternative Examination: The subject weld will receive an 1

inservice inspection in accordance with Code Case N-323, " Alternative Examinations for Integrally Welded Attachments to Vessels".

Code Case N-323 requires that only the accessible side of the support receive a surface examination, provided that stress intensities in region C-D do not exceed 80%

i of the levels A, B, C, and D service limits (NB-3000) and the usage factor "U" does not exceed 0.1.

Licensee's Basis for Reouestino Relief: The licensee states that the geometric configuration of the support skirt-to-shell weld limits examination to the one accessible side of the support (examination surface A-B in Figure IWB-2500-13). The sketch attached to the licensee's relief request shows the interior portion of the subject weld to be inaccessible to a meaningful examination.

.l Radiatior. exposure to erect scaffolding, prepare the weld, and perform the examination on surface C-D is estimated to be 3.1 REM.

Code Case N-323 gives alternative examination requirements for. integrally welded attachments to vessels. The stress intensities and usage factors for the subject region do not exceed the limits specified in the Code Case.

Staff Evaluation:

Examination Category B-H, Item B8.20, requires a surface l

examination of the subject weld as depicted in IWB-2500-13.

The examination is required for both exterior (region A-B) and interior (region C-D) surfaces.

The licensee's proposed alternative is to examine only the accessible side (region A-B) of the support as allowed by Code Case N-323.

As stated by the licensee, the examination of the support skirt-to-shell weld is limited due to geometric configuration that obstructs access to region C-D.

Additionally, radiation levels within the support skirt are expected to be high, therefore, ALARA concerns also exist.

The limited access and radiation hazards make the Code-required examination of the inside surface of the support skirt impractical to perform.

In order to perform the examination to the extent required by the Code, the support skirt would require design modifications and rework to provide access to region C-D.

Imposition of the requirement on the licensee would cause a burden that would not be compensated by an increase in safety above that provided by the limited examination. Therefore, pursuant to 10 CFR 50.55a(g)(6)(1), relief is granted for the inaccessible portion of the pressurizer support skirt-to-shell weld.

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f e

n

. i E.

Reauest for Relief No. IR-9 (Revision 11. Examination Cateaory B-F. Item i

B5.10. and Examination Cateaory B-J. Item B9.11 RPV Nozzle-to-Safe-End and Safe-End-to-Pice Welds Note:

Relief request IR-9 was previously evaluated in the NRC SER dated February 8,1991, which granted relief provided that the licensee demonstrated that the proposed alternative examination, including the procedure and instrumentation, was capable of detecting OD flaws. The licensee has incorporated the conditions of.the SER into Revision 1 of the relief request, therefore, pursuant to 10 CFR 50.55a(a)(3)(i), the proposed alternative i

remains authorized.

r F.

Reauest for Relief No. IR-12. Examination Cateaory C-F-1 and C-F-2.

Itams CS,1). C5.51. and C5.81. Class 2 Pressure Retainina Welds Code Reauirement: Table IWC-2500-1, Examination Category C-F-1 and C-F-2, Items C5.ll and C5.51 require 100% surface and volumetric examination of Class 2 welds in piping greater than 4 inches NPS, and 3/8 inch and greater wall i

thickness, as defined by IWC-2500-7. Examination Category C-F-2, Item C5.81 requires a 100% surface examination of circumferential branch connection welds greater than 2 inches NPS as defined by IWC-2500-9 though IWC-2500-13.

Licensee's Code Relief Reauest:

Relief is requested from performing the surface or volumetric examinations to the extent required by the Code for the following welds, including intersecting longitudinal welds where applicable:

Weld #

% Examinable MSS-33-FW-1-GM 85 i

MSS-33-FW-1-HM 85 MSS-30-FW-2-7M 84 FWS-17-6-SW-E 0

SIL-25-FW-2 90 SIL-25-FW-1-7M 90 1

Licensee's Basis for Recuestina Relief: The required examination volumes or areas are limited due to geometric configuration, permanent obstructions, i

and/or structural interferences that prohibit 100% examination coverage. For the feedwater system (FWS) weld, the required weld is obstructed by a reinforcing pad and is totally inaccessible.

Licensee's Prooosed Alternative Examination: The Code-required volumetric examinations will be performed to the maximum extent practical.

For the branch connection weld in the FWS, a surface examination will be performed on the reinforcing pad-to-pipe weld.

Staff Evaluation:

Items C5.Il and C5.51 require that subject piping welds receive 100% surface and volumetric examinations as defined by the Code.

However, only 85 to 90% of the required volume can be examined due to geometry or other permanent obstructions. Therefore, the Code requirement is

impractical.

In order to perform the volumetric examination to the extent required by the Code, the subject piping and components would have to be redesigned.

Imposition of the requirement on the licensee would cause a burden that would not be compensated by an increase in safety above that provided by the limited examination. The limited examination does include a significant portion (85-90%) of the Code-required volume, thus the structural integrity of the subject welds will be assured. Therefore, pursuant to 10 CFR 50.55a(g)(6)(i), relief is granted.

In the case of the FWS circumferential branch connection weld, the reinforcing j

pad covers the entire weld. The licensee's proposed alternative is to perform a surface examination of the reinforcing pad-to-pipe weld.

This is consistent with Figure IWC-2500-13; thus, the staff concludes that examination of the exposed weld in lieu of the weld obstructed by the reinforcing pad meets the intent of the Code and relief is not required.

G.

Recuest for Relief No. IR-13 (Revision 1). Examination Cateaory C-C.

i Item C3.20. Intearal Attachments for Pioinq l

Note:

Relief Request IR-13 was previously evaluated and granted in an NRC SER l

dated February 8, 1991. The changes in Revision 1 of this relief request amount to editorial changes and do not change the technical content of the request, therefore, relief remains granted for the subject welds.

H.

Recuest for Relief No. IR-15. Examination Cateaory D-A and D-B.

Items Dl.20. D1.30. 01.40. 01.50. 01.60. 02.20. 02.30. D2-40. 02.50.

i and D2.60. Class 3 Intearal Attachments Code Reauirement: Table IWD-2500-1, Examination Category D-A and D-B, Items Dl.20, DI.30, Dl.40, DI.50, DI.60, D2.20, D2.30, D2.40, D2.50, and D2.60, all require VT-3 visual examination of Class 3 integral attachments as defined by IWD-2500-1.

In the case of multiple components within a system of similar design, function, and service, the integral attachment of only one of the multiple components shall be examined. The integral attachments selected for examination shall correspond to those component supports selected by IWF-2510(b).

I licensee's Code Relief Recuest:

Relief is requested from performing the inservice VT-3 visual examination on the Class 3 integrally welded attachments that correspond to the pipe supports selected in accordance with IWF-2510(b).

This request is limited to the inaccessible portions of welded attachments that are under insulation.

i Licensee's Basis for Recuestina Relief: The licensee states that the requirements for selecting integrally welded attachments for Class-3 systems are misleading and confusing. The selection of component supports in accordance with Section XI, Subsection IWF-2510, requires that the supports examined correspond to the integral attachments selected per Subsection IWD.

l Table IWD-2500-1, Note (3) requires the selection of integral attachments that correspond to those component supports selected by IWF-2510(b).

j l

_g_

A conservative interpretation of these requirements would be that all Class 3 integrally welded attachments require a VT-3 examination.

In addition, only Class 3 component supports with integral attachments would require examination.

[

The subject welds received a visual examination during preservice inspection, in accordance with Section XI, thus assuring structural integrity.

In addition, the corresponding component supports receive a VT-3 visual r

examination in accordance with IWA-2213, giving further assurance of structural integrity.

The licensee also states that there has not been an inservice integral attachment failure at Millstone, Unit 3, or any other plants, during the last 20 years (based on a recent survey of utilities).

Category D-A and D-B integral attachments are subject to potential failures due to either operational transients or excessive corrosion.

Inservice inspection examination should be aimed at identifying these conditions.

Licensee's Proposed Alternative Examination:

Selection criteria for examination for Class 3 integral attachments will be as follows:

1.

Integral attachments not exempted by IWD-1220.

2.

In systems that have been determined to be subject to corrosion, a minimum of 25% of Class 3 integrally welded attachments, distributed among attachments, will be examined.

3.

In systems not subject to corrosion, a minimum of 10% of integrally welded attachments will be examined.

4.

1n addition, examination of the integrally welded attachments will be required whenever a component support member has been found to be deformed inservice (i.e., bent or broken), indicating operation transients.

Staff Evaluation:

Examination Category D-B requires a VT-3 visual examination of integral attachments in accordance with Note 3 of Table IWD-2500-1. Note 3 states: "In the case of multiple components within a system of similar design, function, and service, the integral attachment of only one of the multiple components shall be examined. The integral attachments selected for examination shall correspond to those component supports selected by IWF-2510(b)."

Editions and Addenda of ASME Section XI prior to the 1990 Addenda have been unclear regarding selection criteria for component supports, and subject to a brcad spectrum of interpretation. Therefore, many recent relief requests involving supports have been evaluated with respect to Code Case N-491, which is incorporated into the 1990 Addenda. These new requirements for selection of component supports include examination of at least 10% of Class 3 piping supports, and 100% of supports other than piping supports.

I

The licensee proposes to examine at least 25% of integrally welded attachments in systems subject to corrosion, and 10% of all other integrally welded attachments.

The licensee specifically states that this request only applies to inaccessible portions of pipes with welded attac; ats that are under insulation, but has failed to identify the impracticality associated with removing the insulation. Therefore, relief is denied based on inadequate justification.

I.

Reouest for Relief No. IR-16. Examination Cateoory B-A. Item Bl.21. RPV Circumferential Head Welds Note:

Request for Relief No. IR-16 was withdrawn by the licensee in the June 1,1992 submittal as a result of the April 13, 1992 conference call.

J.

Recuest for Relief No. IR-17. Examination Cateaory B-G-1. Items B6.20 and B6.30. Examination Cateoory C-D. Item C4.40. Class 1 and 2 Pressure Retainino Boltino Greater Than 2 Inches Code Reauirement: Table IWB-2500-1, Examination Category B-G-1, Item B6.20, requires a volumetric examination of closure studs, in place, as defined by IWB-2500-12.

Item B6.30, requires volumetric and surface examinations of closure studs, when removed, as defined by the same figure.

Table IWC-2500-1, Examination Category C-D, Item C4.40, requires a volumetric ' examination of i

valve bolts and studs as defined by IWC-2500-6.

Licensee's Code Relief Recuest:

Relief is requested from performing the Code-l required volumetric examinations of pressure retaining bolting greater than 2 inches in accordance with Figures IWB-2500-12 and IWC-2500-6.

Licensee's Proposed Alternative Examination: An alternative volumetric examination will be performed in accordance with Code Case N-307, " Revised Ultrasonic Examination Volume for Class 1 Bolting, Examination Category B-G-1,Section XI, Division 1, When Examinations Are Conducted From the Center Drilled Hole". A 70* refracted longitudinal wave examination will be perform from the center to cover the volume defined as A-B-C-D-E-F-A in the subject code case. The OD surfaces of the Class 1 bolting shall receive a surface examination ~when removed, as required by the referenced Code section.

Licensee's Basis for Recuestina Relief:

The licensee states that Code Case N-307 allows for the volumetric examination to be performed from the center hole of the stud, which is better able to detect flaws in the area where flaws are most likely to exist. This Code Case has been superseded by Code Case N-307-1, which allows the alternative volumetric examination if a surface examination of the center hole is also performed. While this requirement provides for a very thorough inspection, the likelihood of any problems in the center hole is very small. The most highly stressed, and therefore, the area of greatest interest of a fastener is the thread region.

If problems do occur, they

si a

usually originate in a thread.

Hence, doing a volumetric examination from the center hole, in accordance with Code Case N-307, will cover the critical areas and ensure the integrity of the studs.

Staff Evaluation:

Item B6.20 requires that Class I reactor vessel closure studs receive a volumetric examination of the entire volume as defined by Figure IWB-2500-12 (not IWB-2500-5, as identified by the licensee). The licensee's proposed alternative is to perform a volumetric examination from the center drilled hole of the stud in accordance with Code Case N-307. The volume examined in this case is only the outer most volume of the stud; the inner volume is not examined.

Code Case N-307 was superseded by Code Case N-307-1, which revised the requirements of the original code case by supplementing the volumetric examination of the outer portion with a surface examination of the center bore hole. The Code Committee felt that examination of the inner surface was warranted, but had been overlooked in the original code case..Although the threaded portions are the more critical region to examine, the center bore hole surface should not be neglected. Therefore, use of Code Case N-307 is not an acceptable alternative.

Item C4.40 requires a volumetric examination of Class 2 bolts and studs for valves as defined by IWC-2500-6. Although the Licensee has included this item in the relief request, there is no discussion, or proposed alternative for the Class 2 bolting, therefore, this request cannot be evaluated.

Based on the above evaluation, the staff concludes that the licensee's proposed alternative is unacceptable for Class 1 studs, and non-existent for Class 2 bolting.

In addition, the Class 2 portion of the request lacks sufficient information, and cannot be evaluated. Therefore, relief is denied.

K.

Recuest for Relief No. IR-18. Schedulina Reouirements for Examination a

Cateoory B-H. Item B8.20. Pressurizer Inteorally Welded Attachments Code Reouirement: Table IWB-2500-1, Examination Category B-H, Item B8.20, requires a volumetric or surface examination of pressurizer integrally welded attachments, as defined by IWB-2500-13, -14, or -15 (as applicable).

l Examination shall be distributed among inspection periods, as specified in Table IWB-2412-1, Inspectica Program B.

l Licensee's Code Relief Recuest:

Relief is requested from the scheduling requirements of IWB-2412-1 for eight pressurizer integrally welded attachments.

Licensee's Basis for Recuestino Relief: Millstone, Unit 3 has nine integrally welded attachments in Examination Category B-H.

Eight of these provide component support for the pressurizer and are located near the top head.

In order to meet the scheduling requirement of the Code for Examination Category B-H, insulation on the pressurizer would have to be removed three times during a 10-year interval.

d The Millstone, Unit 3 ISI Program currently schedules most of the pressurizer volumetric and surface examinations during one refueling outage in order to allow this insulation to be removed only once. The high exposure levels in the pressurizer cubicle make it prudent from an ALARA standpoint to do this.

Licensee's Procosed Alternative Examination:

Examination of the eight integral attachments for the pressurizer support brackets was performed in accordance with Figure IWB-2500-15 during the second inspection period.

Staff Evaluation:

IWB-2412-1 requires that examinations be distributed among inspection periods. The licensee's proposed alternative is to perform the Code-required examinations of 8 (of 9) Examination Category B-H integrally welded attachments during the second inspection period.

The subject integrally welded attachments are all located near the top head of the pressurizer.

In order to examine the welds in accordance with the Code, the insulation would have to be removed three separate times. The intent of the Code is to distribute examinations among components to ensure that generic failure mechanisms are detected. However, at Millstone, Unit 3, 8 of the 9 Class 1 integrally welded attachments are located on the same component, which means that the same insulation would have to be removed during each of the three inspection periods.

Considering the high radiation levels in the pressurizer cubicle, removal of the insulation on the pressuriar three times during an interval represents excessive personnel exposure and is imprudent from an ALARA standpoint.

In addition, there is only one other Category o-H weld at Millstone, Unit 3, so distribution of examination among other Class 1 vessels is not possible. Therefore, the scheduling requirements of the Code are impractical.

Imposition of the requirement on the licensee would cause a burden that would not be compensated by an increase in safety above that provided by performing all of the required examinations during the same inspection period.

Based on the above, and pursuant to 10 CFR 50.55a(g)(6)(i), it is concluded that relief may be granted as requested.

3.0 CONCLUSION

The staff concludes that the Millstone Nuclear Power Station, Unit 3, first 10-year Interval. ISI Program Summary Report, Revision 3 is unacceptable and not in compliance with the regulations.

In order to become acceptable, volumetric examination of 7.5% of the welds in the Class 2 CHS and SIH systems must be included in the ISI program.

Pursuant to 10 CFR 50.55a(g)(5)(iii), the licensee determined that conformance with certain Code requirements is impractical for his facility and submitted supporting information. The staff has reviewed the licensee's submittal and 1

has concluded that there are cases where relief can be granted as requested.

Pursuant to 10 CFR 50.55a(g)(6)(i), the staff concludes that the requirements of the Code are impractical and relief may be granted for Relief Requests IR-1 (Rev. 3), IR-2 (Rev. 2) (in part), IR-6, IR-12 (in part), IR-13 (Rev. 1), and se

i.

IR-18. Pursuant to 10 CFR 50.55a(a)(3)(i), the proposed alternative described in Request for Relief IR-9 (Rev. 1) is authorized. Such relief is authorized by law and will not endanger life, property, or the common defense and security, and is otherwise in the public interest. The relief has been granted giving due consideration to the burden upon the licensee that could result if the requirements were imposed on the facility.

For Request for Relief IR-12, it was determined that relief was not required for the FWS weld.

For Request for Relief IR-2, it was determined that relief was not required for Weld #101-104D since essentially 100% of the weld was examined.

Request for Relief IR-17 is denied based on the use of an out-of-date code case. Request for Relief IR-15 is denied due to insufficient justification.

Request for Relief IR-16 was withdrawn by the licensee.

Principal Contributor:

T. K. McLellan Date:

March 3, 1993

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