ML050940136

Relief, Relaxation of First Revised Order on Reactor Vessel Nozzles

ML050940136
Person / Time
Site:	Indian Point
Issue date:	04/04/2005
From:	Holden C NRC/NRR/DLPM/LPD1
To:	Kansler M Entergy Nuclear Operations
Milano P, NRR/DLPM , 415-1457
References
TAC MC6508
Download: ML050940136 (15)

Text

April 4, 2005 Mr. Michael R. Kansler, President Entergy Nuclear Operations, Inc.

440 Hamilton Avenue White Plains, NY 10601

SUBJECT:

RELAXATION OF FIRST REVISED ORDER ON REACTOR VESSEL NOZZLES, INDIAN POINT NUCLEAR GENERATING UNIT NO. 3 (TAC NO. MC6508)

Dear Mr. Kansler:

In a letter dated March 30, 2005, as supplemented on April 1, 2005, Entergy Nuclear Operations, Inc. (the licensee), submitted a request for relaxation regarding the inspection of reactor pressure vessel (RPV) head and penetration nozzles at Indian Point Nuclear Generating Unit No. 3 (IP3). The relaxation was requested from the interim inspection requirements in the Nuclear Regulatory Commissions (NRCs) First Revised Order Modifying Licenses, EA-03-009, dated February 20, 2004 (First Revised Order).

On March 18, 2005, the NRC authorized certain alternatives to the inspection requirements in the First Revised Order for IP3 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML050770010). As stated in its March 30 application, the licensee had originally requested that the relaxation be applicable to 5 penetrations that were identified based on fabrication drawings for the RPV head. However, based on actual inspections and measurements performed during the current refueling outage that commenced on March 11, 2005, the licensee has identified additional penetrations for which relaxation is required.

Additionally, the licensee found that the data on one of the penetrations previously approved for relaxation by the NRC needed to be revised based on actual field conditions determined during the current refueling outage. In a letter dated April 1, 2005, the licensee included 3 more penetrations that were inspected during the previous outage and needed to be revised after comparison to the measured field data. Therefore, these penetrations are included in the current relaxation request in order to update the prior relaxation to approve the lower inspection boundary.

The NRC staff has reviewed the licensees requested relaxation to implement certain alternatives to the requirements of the First Revised Order at IP3. Specifically, the licensee proposed relaxation from the inspection coverage for the nondestructive examination, using ultrasonic testing techniques, of 32 RPV head penetration nozzles, that are limited by a threaded section that is less than the 1 inch lower boundary limit specified in Section IV.C.5.(b)(i) of the First Revised Order. The results are provided in the enclosed safety evaluation (SE).

For the examination coverage regarding the 36 RPV penetration nozzles, the NRC staff has concluded for IP3 that the proposed alternative examinations provides reasonable assurance of the structural integrity. Further inspections of these nozzles in accordance with paragraph C.(5)(b) of Section IV of the First Revised Order would result in hardship without a compensating increase in the level of quality and safety. Therefore, pursuant to

M. Kansler 10 CFR 50.55a(a)(3)(ii), and in accordance with Section IV, paragraph F, of the First Revised Order, the NRC staff authorizes the proposed alternative inspection for the 36 RPV penetration nozzles at IP3 for the life of the Order, subject to the condition specified in the SE.

If you should have any questions, please contact Patrick Milano at 301-415-1457.

Sincerely,

/RA/

Cornelius F. Holden, Director Project Directorate I Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No. 50-286

Enclosure:

As stated cc w/encl: See next page

M. Kansler 10 CFR 50.55a(a)(3)(ii), and in accordance with Section IV, paragraph F, of the First Revised Order, the NRC staff authorizes the proposed alternative inspection for the 36 RPV penetration nozzles at IP3 for the life of the Order, subject to the condition specified in the SE.

If you should have any questions, please contact Patrick Milano at 301-415-1457.

Sincerely,

/RA/

Cornelius F. Holden, Director Project Directorate I Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No. 50-286

Enclosure:

As stated cc w/encl: See next page DISTRIBUTION:

PUBLIC PDI-1 R/F W. Kane/S. Rosenberg J. Dyer R. Borchardt B. Sheron T. Marsh/J. Lyons M. Mayfield C. Holden B. Bateman F. Congel R. Laufer T. Chan J. Luehman P. Milano B. McDermott, R-I G. Matakas, R-I E. Reichelt W. Koo S. Little S. Bloom S. Burnell, OPA C. Miller, EDO SECY ACRS OGC G. Hill (2)

Accession Number: ML050940136 OFFICE PDI-1:PM PDI-1:LA EMCB:SC OGC PDI-1:SC PDI:D NAME PMilano SLittle TChan JHull RLaufer CHolden DATE 04/04/05 04/04/05 04/01/05 04/04/05 04/04/05 04/04/05 OFFICIAL RECORD COPY

Indian Point Nuclear Generating Unit No. 3 cc:

Mr. Gary J. Taylor Chief Executive Officer Entergy Operations, Inc.

1340 Echelon Parkway Jackson, MS 39213 Mr. John T. Herron Senior Vice President and Chief Operating Officer Entergy Nuclear Operations, Inc.

440 Hamilton Avenue White Plains, NY 10601 Mr. Fred Dacimo Site Vice President Entergy Nuclear Operations, Inc.

Indian Point Energy Center 295 Broadway, Suite 2 P.O. Box 249 Buchanan, NY 10511-0249 Mr. Christopher Schwarz General Manager, Plant Operations Entergy Nuclear Operations, Inc.

Indian Point Energy Center 295 Broadway, Suite 2 P.O. Box 249 Buchanan, NY 10511-0249 Mr. Danny L. Pace Vice President Engineering Entergy Nuclear Operations, Inc.

440 Hamilton Avenue White Plains, NY 10601 Mr. Brian OGrady Vice President Operations Support Entergy Nuclear Operations, Inc.

440 Hamilton Avenue White Plains, NY 10601 Mr. John McCann Director, Nuclear Safety Assurance Entergy Nuclear Operations, Inc.

440 Hamilton Avenue White Plains, NY 10601 Ms. Charlene D. Faison Manager, Licensing Entergy Nuclear Operations, Inc.

440 Hamilton Avenue White Plains, NY 10601 Mr. Michael J. Colomb Director of Oversight Entergy Nuclear Operations, Inc.

440 Hamilton Avenue White Plains, NY 10601 Mr. James Comiotes Director, Nuclear Safety Assurance Entergy Nuclear Operations, Inc.

Indian Point Energy Center 295 Broadway, Suite 1 P.O. Box 249 Buchanan, NY 10511-0249 Mr. Patric Conroy Manager, Licensing Entergy Nuclear Operations, Inc.

Indian Point Energy Center 295 Broadway, Suite 1 P. O. Box 249 Buchanan, NY 10511-0249 Mr. John M. Fulton Assistant General Counsel Entergy Nuclear Operations, Inc.

440 Hamilton Avenue White Plains, NY 10601 Regional Administrator, Region I U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 Senior Resident Inspectors Office Indian Point 3 U. S. Nuclear Regulatory Commission P.O. Box 337 Buchanan, NY 10511-0337

Indian Point Nuclear Generating Unit No. 3 cc:

Mr. Peter R. Smith, President New York State Energy, Research, and Development Authority 17 Columbia Circle Albany, NY 12203-6399 Mr. Paul Eddy Electric Division New York State Department of Public Service 3 Empire State Plaza, 10th Floor Albany, NY 12223 Mr. Charles Donaldson, Esquire Assistant Attorney General New York Department of Law 120 Broadway New York, NY 10271 Mayor, Village of Buchanan 236 Tate Avenue Buchanan, NY 10511 Mr. Ray Albanese Executive Chair Four County Nuclear Safety Committee Westchester County Fire Training Center 4 Dana Road Valhalla, NY 10592 Ms. Stacey Lousteau Treasury Department Entergy Services, Inc.

639 Loyola Avenue Mail Stop: L-ENT-15E New Orleans, LA 70113 Mr. William DiProfio PWR SRC Consultant 139 Depot Road East Kingston, NH 03827 Mr. Dan C. Poole PWR SRC Consultant 20 Captains Cove Road Inglis, FL 34449 Mr. William T. Russell PWR SRC Consultant 400 Plantation Lane Stevensville, MD 21666-3232 Mr. Jim Riccio Greenpeace 702 H Street, NW Suite 300 Washington, DC 20001

Enclosure SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELAXATION OF FIRST REVISED ORDER MODIFYING LICENSES, EA-O3-009 EXAMINATION COVERAGE FOR REACTOR PRESSURE VESSEL HEAD AND PENETRATIONS NOZZLES INDIAN POINT NUCLEAR GENERATING UNIT NO. 3 ENTERGY NUCLEAR OPERATIONS, INC.

DOCKET NO. 50-286

1.0 INTRODUCTION

On February 20, 2004 (Agencywide Documents Access and Management System (ADAMS)

Accession No. ML040220181), the Nuclear Regulatory Commission (NRC) issued the First Revised NRC Order Modifying Licenses, EA-03-009 (First Revised Order), requiring specific examinations of the reactor pressure vessel (RPV) head and vessel head penetration (VHP) nozzles of all pressurized-water reactor (PWR) plants.Section IV, paragraph F, of the First Revised Order states that requests for relaxation of the Order associated with specific penetration nozzles will be evaluated by the NRC staff using the procedure for evaluating proposed alternatives to the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code) in accordance with Section 50.55a(a)(3) of Part 50 of Title 10 of the Code of Federal Regulations (10 CFR 50.55a(a)(3)).Section IV, paragraph F, of the Order states that a request for relaxation regarding inspection of specific nozzles shall address the following criteria: (1) the proposed alternative(s) for inspection of specific nozzles will provide an acceptable level of quality and safety, or (2) compliance with this Order for specific nozzles would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.

For Indian Point Nuclear Generating Unit No. 3 (IP3) and similar plants that were determined to have a moderate susceptibility to primary water stress-corrosion cracking (PWSCC) in accordance with Section IV, paragraphs A and B, of the First Revised Order, the following inspections shall be performed such that at least the requirements of paragraph IV.C.(5)(a) or paragraph IV.C.(5)(b) are performed each refueling outage:

(a)

Bare metal visual [BMV] examination of 100 percent of the RPV head surface (including 360E around each RPV head penetration nozzle). For RPV heads with the surface obscured by support structure interferences which are located at RPV head elevations downslope from the outermost RPV head penetration, a bare metal visual inspection of no less than 95 percent of the RPV head surface may be performed provided that the examination shall include those areas of the RPV head upslope and downslope from the support structure interference to identify any evidence of boron or corrosive product. Should any evidence of boron or corrosive product be identified, the licensee shall examine the RPV head surface under the support structure to ensure that the RPV head is not degraded.

(b)

For each penetration, perform a nonvisual NDE [nondestructive examination] in accordance with either (i), (ii) or (iii):

(i)

Ultrasonic testing of the RPV head penetration nozzle volume (i.e., nozzle base material) from 2 inches above the highest point of the root of the J-groove weld (on a horizontal plane perpendicular to the nozzle axis) to 2 inches below the lowest point at the toe of the J-groove weld on a horizontal plane perpendicular to the nozzle axis (or bottom of the nozzle if less than 2 inches [See Figure IV-1]); OR from 2 inches above the highest point of the root of the J-groove weld (on a horizontal plane perpendicular to the nozzle axis) to 1.0-inch below the lowest point at the toe of the J-groove weld (on a horizontal plane perpendicular to the nozzle axis) and including all RPV head penetration nozzle surfaces below the J-groove weld that have an operating stress level (including all residual and normal operation stresses) of 20 ksi tension and greater (see Figure IV-2). In addition, an assessment shall be made to determine if leakage has occurred into the annulus between the RPV head penetration nozzle and the RPV head low-alloy steel.

(ii)

Eddy current testing or dye penetrant testing of the entire wetted surface of the J-groove weld and the wetted surface of the RPV head penetration nozzle base material from at least 2 inches above the highest point of the root of the J-groove weld (on a horizontal plane perpendicular to the nozzle axis) to 2 inches below the lowest point at the toe of the J-groove weld on a horizontal plane perpendicular to the nozzle axis (or the bottom of the nozzle if less than 2 inches [see Figure IV-3]); OR from 2 inches above the highest point of the root of the J-groove weld (on a horizontal plane perpendicular to the nozzle axis) to 1.0-inch below the lowest point at the toe of the J-groove weld (on a horizontal plane perpendicular to the nozzle axis) and including all RPV head penetration nozzle surfaces below the J-groove weld that have an operating stress level (including all residual and normal operation stresses) of 20 ksi tension and greater (see Figure IV-4).

(iii)

A combination of (i) and (ii) to cover equivalent volumes, surfaces and leak paths of the RPV head penetration nozzle base material and J-groove weld as described in (i) and (ii). Substitution of a portion of a volumetric exam on a nozzle with a surface examination may be performed with the following requirements:

1.

On nozzle material below the J-groove weld, both the outside diameter and inside diameter surfaces of the nozzle must be examined.

2.

On nozzle material above the J-groove weld, surface examination of the inside diameter surface of the nozzle is permitted provided a surface examination of the J-groove weld is also performed.

In addition, for those plants in the Moderate category, the requirements of paragraph IV.C.(5)(a) and paragraph IV.C.(5)(b) shall each be performed at least once over the course of every 2 refueling outages.

Footnote 3 of the Order provides specific criteria for examination of repaired VHP nozzles.

By letter dated March 30, 2005 (ADAMS Accession No. ML050900405), as supplemented on April 1, 2005, Entergy Nuclear Operations, Inc. (Entergy, or the licensee) requested relaxation to implement an alternative to the requirements of Section IV, paragraph C.(5)(b) of the First Revised Order for RPV head penetration nozzles at IP3. The specific relaxation requested is provided below.

2.0 FIRST REVISED NRC ORDER EA-03-009 RELAXATION REQUEST FOR EXAMINATION COVERAGE FOR REACTOR PRESSURE VESSEL HEAD AND PENETRATION NOZZLES 2.1 First Revised NRC Order Requirements for Which Relaxation is Requested The licensee has requested relaxation from Section IV, Paragraph C.(5)(b)(i) of the First Revised NRC Order. The specific relaxation is identified below.

2.2 Licensees Proposed Alternative The licensee seeks relaxation from the Order where inspection coverage is limited by a threaded section which is less than the 1 inch lower boundary limit specified in paragraph IV.C.(5)(b)(i) of the First Revised NRC Order for 36 RPV head penetration nozzles at IP3, with respect to NDE, specifically ultrasonic testing (UT). The licensee stated that relaxation is requested from Paragraph IV, C.(5)(b)(i) of the Order from 1.0 inch below the lowest point at the toe of the J-groove weld (on a horizontal plane perpendicular to the nozzle axis) and including all RPV head penetration nozzle surfaces below the J-groove weld that have an operating stress level (including all residual and normal operation stresses) of 20 ksi tension and greater (see Figure IV-2 of the First Revised Order).

The licensee proposes to define the lower boundary of the inspection volume for the affected RPV head penetration nozzles as: to the top of essentially the start of the threaded region, which varies for each nozzle, below the lowest point at the toe of the J-groove weld... including all RPV head penetration nozzle surfaces below the J-groove weld that have an operating stress level (including all residual and normal operation stresses) of 20 ksi tension and greater.

2.3 Reason for Relaxation Request The proposed alternative provides an acceptable level of quality and safety.

2.4 Licensees Basis for Proposed Alternative The licensee stated that the design of the RPV head penetration nozzles at IP3 includes a threaded section, approximately 3/4-inch long, at the bottom of the nozzles. At 36 locations, the dimensional configuration is such that the distance from the lowest point at the toe of the J-groove weld to the bottom of the scanned region (essentially the start of the threaded region) is less than the 1 inch lower boundary limit specified in Paragraph IV.C.(5)(b)(i) of the First Revised NRC Order. The licensee stated that since UT and eddy current testing (ECT) results would not be meaningful in the threaded region, Entergy proposes that the lower boundary of the inspection extend essentially to the start of the threaded region for UT. ECT scanning obtained greater than 1-inch coverage on the inside diameter (ID) surface of the nozzle tube below the lowest point at the toe of the J-groove weld with no relevant indications noted. Leak path assessments were performed and no leakage was noted. A table is provided below which lists the penetrations affected by the relaxation request, the extent of UT and ECT scanning below the lowest point at the toe of the J-groove weld, the angle of incidence, and the operating stresses.

Penetration UT Exam Coverage Outside Diameter (OD)

Downhill UT Exam Coverage OD Uphill ECT Exam Coverage ID Angle of Incidence (degrees)

Operating Stress, psi Downhill Operating Stress, psi Uphill 7

0.93 1.81 1.67 11.4 13597

-38193 10 0.89 2.21 1.59 16.2 13597

-38193 16 0.97 2.37 1.63 18.2 13597

-38193 22 0.85 2.33 1.71 23.2 13597

-38193 24 0.85 2.77 1.59 23.2 13597

-11176 38 0.69 3.01 1.47 30.2 16038

-11176 39 0.89 3.17 1.59 30.2 13597

-11176 40 0.81 3.13 1.51 30.2 13597

-11176 41 0.81 3.41 1.51 30.2 13597

-11176 Penetration UT Exam Coverage OD Downhill UT Exam Coverage OD Uphill ECT Exam Coverage ID Angle of Incidence (degrees)

Operating Stress, psi Downhill Operating Stress, psi Uphill 42 0.77 3.37 1.51 30.2 16038

-11176 43 0.77 3.17 1.47 30.2 16038

-11176 44 0.65 3.21 1.47 30.2 16038

-11176 47 0.73 3.69 1.39 33.9 16038

-11176 48 0.73 3.65 1.47 33.9 16038

-11176 49 0.81 3.89 1.51 33.9 13597

-11176 50 0.77 3.69 1.51 35.1 16038

-11176 52 0.69 3.73 1.43 35.1 16038

-11176 53 0.77 3.85 1.51 35.1 16038

-11176 55 0.73 3.93 1.51 35.1 16038

-11176 56 0.73 3.97 1.43 35.1 16038

-11176 57 0.97 3.77 1.75 35.1 13597

-11176 60 0.85 3.77 1.67 36.3 13597

-11176 61 0.73 3.77 1.51 36.3 16038

-11176 62 0.73 4.09 1.55 38.6 16038

-11176 65 0.73 4.41 1.39 38.6 16038 8161 66 0.85 4.29 1.63 38.6 13597 8161 67 0.65 4.13 1.43 38.6 16038

-11176 68 0.81 4.01 1.63 38.6 13597

-11176 70 0.81 4.89 1.47 44.3 13597 8161 71 0.45 5.13 1.15 44.3 31818 8161 73 0.81 5.29 1.47 44.3 13597 8161 78 0.76 5.20 1.67 48.8 16038 8161 Penetration UT Exam Coverage OD)Down hill UT Exam Coverage OD Uphill ECT Exam Coverage ID Angle of Incidence (degrees)

Operating Stress, psi Downhill Operating Stress, psi Uphill 74*

1.00 5.88 1.62 48.8 13597 8161 75*

0.52 5.44 1.44 48.8 22536 8161 76*

0.64 6.00 1.26 48.8 16038 8161 77*

0.72 5.80 1.34 48.8 16038 8161 78*

0.84 5.20 1.67 48.8 13597 8161

• The licensee stated that the data identified above for penetrations 74, 75, 76, 77, and 78 was collected during the inspection performed during refueling outage 3R12, spring 2003, in response to initial Order EA-03-009. The licensee also stated that penetrations 74 through 77 were not reinspected during the spring 2005 refueling outage (3R13), but will be inspected in the next refueling outage scheduled for spring 2007 (3R14).

The reported lengths of 75, 76, 77, and 78 have changed from the initial relaxation request which was approved by the NRC on March 18, 2005. In a letter dated April 1, 2005, the licensee stated the change in dimensions taken from drawings (which was their basis for the prior relaxation request), as compared to the measured field data, which is now the basis for this relaxation request. The licensee stated the current relaxation request is intended to update the prior relaxation to include approval of the lower inspection boundary of penetrations 75, 76, 77, and 78 based on field data.

The licensee stated that it confirmed through analysis that the operating stress levels (including all residual and normal operating stresses), in the region at and below the proposed lower boundary limit of the inspection volume, are less than 20 ksi tension, except for penetration nos. 71 and 75. The licensee performed a crack growth evaluation for penetration 71 and the results will be discussed in the staff evaluation.

In addition, the licensee complied with the requirement for determining if leakage has occurred into the annulus between the RPV head penetration nozzle and the RPV head. This determination was made by the BMV examination at the top of the RPV head surface that includes inspection 360E around each of the head penetration nozzles, augmented by a UT examination of the interference fit zone for evidence of leakage.

2.5 Evaluation The NRC staffs review of this request was based on criterion (2) of paragraph F of Section IV of the Order which states:

[C]ompliance with this Order for specific nozzles would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.

Within the context of the licensees proposed alternative examination of the RPV head penetration nozzles, the licensee has demonstrated the hardship that would result from implementing examinations to the bottom end of these nozzles. The licensee identified the hardship identified by stating the design of the RPV head penetration nozzles includes a threaded section, approximately 3/4-inch long, at the bottom of the nozzles. At 36 locations, the dimensional configuration is such that the distance from the lowest point at the toe of the J-groove weld to the bottom of the scanned region (essentially the start of the threaded region) is less than the 1-inch lower boundary limit specified in paragraph IV.C.(5)(b) of the First Revised Order. UT and ECT would not provide meaningful results.

The phenomenon of concern is PWSCC, which typically initiates in the areas of highest stress.

The area of RPV head penetration nozzles that has the highest residual stress is the area adjacent to the J-groove attachment weld. Therefore, it is most likely that PWSCC will initiate in an area adjacent to the J-groove attachment weld.

The licensee proposed to examine the minimum distance of the nozzle base material below the J-groove attachment weld to the top of essentially the start of the threaded region, which varies for each nozzle as is identified in the Table above. The licensee has confirmed through analysis that the operating stress levels (including all residual and normal operation stresses),

in the region at and below the proposed lower boundary limit of the inspection volume, are less than 20 ksi tension except for penetrations 71 and 75.

For penetration 71, the maximum inspection length of 0.45 inch below the J-groove weld was inspected by ultrasonic methods. The inspection limitation is due to the dimensions of the as-built reactor vessel head and penetration. The operating stress at the limit of the inspectable location is 31.8 ksi. The licensees inspection included both UT and ECT from the tube ID side. The licensee stated that the ECT examination on the tube ID extended to 1.15 inches below the J-groove weld and no indications were detected. The licensee also performed a leak path assessment and no leakage was noted. The licensee also performed a flaw evaluation in which an axial crack was assumed to start at the bottom of the nozzle on the downhill side and extended axially to the inspection boundary of 0.45 inch. The hypothetical flaw was assumed to be through wall for the entire axial extent. The results show that the crack would require 2.5 effective full-power years (EFPY) to grow from 0.45 inch below the J-groove weld to the bottom of the J-groove weld. The licensee stated that this penetration will be inspected again in refueling outage 3R14, which is scheduled in approximately 2 years. This penetration was also inspected in refueling outage 3R12, with no indications noted. The licensee stated that, for an undetected crack at the beginning of cycle 14 (after startup from the current refueling outage), penetration 71 remains bounding for this relaxation request, which includes penetration 75, with respect to the fracture mechanics analysis of crack growth, based on the highest stress and shortest inspectable length. Penetration 71 will remain bounding for cycle 14 (scheduled for spring 2007) if inspection results remain the same. If inspection results find that non-visual NDE examination coverage is less than 0.45 inch below the toe of the J-groove weld, a new relaxation request will be required to be submitted for NRC review and approval.

The licensees analysis used the crack growth formula in Electric Power Research Institute (EPRI) Report Material Reliability Program (MRP) Report MRP-55, Material Reliability Program (MRP) Crack Growth Rates for Evaluating Primary Water Stress Corrosion Cracking (PWSCC) of Thick Wall Alloy 600 Material (MRP-55), Revision 1. The NRC staff has not yet made a final determination on the acceptability of the subject industry report. Should the NRC staff determine the crack growth formula used by the licensee to be unacceptable, the licensee will be required to revise its analysis to incorporate an acceptable crack growth formula as described below.

If the NRC staff finds that the crack-growth formula in industry report MRP-55 is unacceptable, the licensee shall revise its analysis that justifies relaxation of the First Revised NRC Order within 30 days after the NRC informs the licensee of an NRC-approved crack growth formula. If the licensees revised analysis shows that the crack growth acceptance criteria are exceeded prior to the end of the current operating cycle, this relaxation is rescinded and the licensee shall, within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, submit to the NRC written justification for continued operation. If the revised analysis shows that the crack growth acceptance criteria are exceeded during the subsequent operating cycle, the licensee shall, within 30 days, submit the revised analysis for NRC review. If the revised analysis shows that the crack growth acceptance criteria are not exceeded during either the current operating cycle or the subsequent operating cycle, the licensee shall, within 30 days, submit a letter to the NRC confirming that its analysis has been revised. Any future crack-growth analyses performed for this and future cycles for RPV head penetrations must be based on an acceptable crack growth formula.

The licensee committed to the above statement in a letter dated March 30, 2005. Based upon the information above, the NRC staff finds the licensees crack growth evaluation to be acceptable. The stress of 31.8 ksi is greater than the 20 ksi identified in the Order, and the calculation showed that the assumed crack 0.45 inch below the toe of the J-groove weld will not grow into the weld within one cycle of operation.

The licensee stated that finite element analyses were performed for the Indian Point Unit 2 (IP2) top head configuration by Dominion Engineering and Structural Integrity Associates. The finite element analysis included the simulation of the weld deposition for the J-groove weld buttering and the subsequent stress relief of the head and buttering, in addition to the J-groove welding. The calculations addressed weld residual stresses and applied stresses for the limiting nozzles at IP2, under several repair scenarios. The licensee stated that the head design geometries and operating conditions of IP3 were compared to IP2 and concluded that the analyzed results for IP2 are bounding for IP3. This conclusion is based on the fact that the head geometries for IP2 are similar to IP3 and in some cases even more limiting than the IP3 geometries for top head penetrations. In particular, the licensee stated the head geometries for both units are essentially identical in major dimensions, (i.e., head thickness, diameter, and control rod drive mechanism tube diameter and wall thickness). The materials for both reactor heads are the same. The weld joint geometries are slightly more severe for IP2, in that the J-groove weld leg for IP2 is typically larger and, therefore, has more volume than IP3's at the limiting nozzle locations. The licensee stated that since welding stresses are driven to a great extent by the volume of weld metal through the cooling process, residual stresses for the IP3 welds are expected to be comparable to, if not less than those of IP2. The licensee stated this conclusion is valid for the original as-designed J-groove welds.

The results of the finite element analysis provided the operating condition stress levels and distribution effects of welding residual stresses, hydrostatic testing and steady state operating pressure and temperature. Hoop stress results of the performed analysis are provided in the table above.

The NRC staff finds the licensees analysis to be acceptable because the results show the operating hoop stresses, with the exception of penetrations 71 and 75, are below 20 ksi threshold stress. It is commonly believed that the cracks will not initiate if the available stresses are below the threshold stress of 20 ksi. The licensee performed a crack growth evaluation on penetration 71 as described above, which is the bounding penetration for the others. Results of the crack growth evaluation concluded that a crack would not grow into the J-groove weld within one cycle of operation.

The licensee also identified 5 nozzles (nos. 74, 75, 76, 77, and 78), which are equipped with retaining collar/guide funnels which are welded to the bottom of the nozzles on the OD side.

The licensee described the labor intense effort to remove and re-install the guide funnels in addition to the dose impact. The NRC staff recognized the hardship and concurred in the March 18, 2005, letter that removing the guide funnels would not increase the NDE examination coverage or accuracy.

The licensee stated that inspection methods and results performed during refueling outage 3R12 in April 2003 were submitted in Entergys letter to NRC, NL-03-098, dated June 12, 2003.

The non-visual NDE portion of the examination for the referenced 5 penetration nozzles (i.e.,

nos. 74, 75, 76, 77, and 78) was performed using a single probe assembly that contained a pair of transducers for the UT examination and an eddy current coil for the ECT surface examination. The axial coverage with this probe assembly extended down to approximately 0.75 inch from the bottom of the nozzle (for the UT exam) and down to approximately 0.25 inch from the bottom of the nozzle (for the ECT surface exam). Meaningful UT data below approximately 0.75 inch was limited by signal dispersion in the threaded region. Meaningful ECT data below approximately 0.25 inch was also limited because the eddy current coil tends to lose contact with the examination surface as it reaches the lead-in chamfer region. The hardships of removing the guide funnels welded to the bottom of the nozzles precludes examination of the OD wetted surface areas of the nozzle tubes. The NRC staff recognized the hardship and concurred in the March 18, 2005, letter that removing the guide funnels would not increase the NDE examination coverage or accuracy.

The licensee stated the inspection methods and results performed during the present refueling outage 3R13 included no less than 95% BMV examination (including 360E around all penetrations) and NDE of 51 penetrations. The NDE portion of the examination used a Trinity probe assembly for thermal sleeve penetrations and a 7010 probe for open-hole penetrations.

The NDE probes contain transducers to complete UT, leakage path assessments, and an ECT for the surface examination. The licensee stated that UT data could not be achieved below the threaded area on the OD of the tube. In all cases, the ECT was completed greater than 1 inch on the tube ID.

Based on the information above, the NRC staff concludes the non-visual NDE inspections and coupled with the remote BMV examination of the top surface of the vessel head performed in refueling outage 3R12 in 2003 and refueling outage 3R13 in 2005 to be acceptable because there were no signs of RPV head degradation or PWSCC of the Alloy 600 penetration nozzles.

3.0 CONCLUSION

The NRC staff concludes that the licensees proposed alternative examination of the 36 RPV penetration nozzles (including 74, 75, 76, 77, and 78 which were previously inspected in refueling outage 3R12 in 2003 and relaxation approved in NRC letter dated March 18, 2005) from 0.45 inch below the lowest point at the toe of the J-groove weld, which is the top of the threaded region, provides reasonable assurance of the structural integrity of the RPV head, RPV penetration nozzles, and welds. Further inspections of these RPV penetration nozzles in accordance with Section IV, paragraph C.(5)(b), of the First Revised NRC Order EA-03-009, dated February 20, 2004, would result in hardship without a compensating increase in the level of quality and safety. Therefore, pursuant to Section IV, paragraph F, of the First Revised NRC Order EA-03-009, dated February 20, 2004, the NRC staff authorizes the proposed alternative inspection for the 36 RPV penetration nozzles at IP3 for the life of the Order, subject to the following condition:

If the NRC staff finds that the crack-growth formula in industry report MRP-55 is unacceptable, the licensee shall revise its analysis that justifies relaxation of the First Revised Order dated February 20, 2004, within 30 days after the NRC informs the licensee of an NRC-approved crack growth formula. If the licensees revised analysis shows that the crack growth acceptance criteria are exceeded prior to the end of the current operating cycle, this relaxation is rescinded and the licensee shall, within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, submit to the NRC written justification for continued operation. If the revised analysis shows that the crack growth acceptance criteria are exceeded during the subsequent operating cycle, the licensee shall, within 30 days, submit the revised analysis for NRC review. If the revised analysis shows that the crack growth acceptance criteria are not exceeded during either the current operating cycle or the subsequent operating cycle, the licensee shall, within 30 days submit a letter to the NRC confirming that its analysis has been revised. Any future crack-growth analyses performed for this and future cycles for RPV head penetration nozzles must be based on an acceptable crack growth rate formula.

The NRC staff notes that the evaluations performed above were done for IP2 RPV head. The licensee stated that the design for IP3 is identical and the same restrictions encountered at IP2 can be anticipated for IP3. If the restrictions encountered in IP3 inspection are more restrictive than the approved relaxation, the licensee will need to submit a new relaxation request for IP3.

Principal Contributor: E. Reichelt Date: 04/04/05