ML040610545
| ML040610545 | |
| Person / Time | |
|---|---|
| Site: | Monticello, Duane Arnold  |
| Issue date: | 02/27/2004 |
| From: | Weinkam E Nuclear Management Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML040610545 (7) | |
Text
________________________________
Nuclear Management Company, LLC February 27, 2004 10 CFR 50.55a(a)(3)(i)
U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Duane Arnold Energy Center Docket 50-331 License No. DPR-49 Monticello Nuclear Generating Plant Docket 50-263 License No. DPR-22 Request For Authorization To Utilize Code Case N-613-1 Pursuant to 10 CFR 50.55a(a)(3)(i), Nuclear Management Company, LLC (NMC) hereby requests NRC approval of the enclosed request for the Duane Arnold Energy Center (DAEC) and Monticello Nuclear Generating Plant (MNGP). Authorization is requested to use the alternative examination volume requirements of Code Case N-613-1, Ultrasonic Examination of Full Penetration Nozzles in Vessels, Examination Category B-D, Item Nos. B3.10 and B3.90, Reactor Nozzle-To-Vessel Welds, Figs. IWB-2500-7(a), (b), and (c),Section XI, Division 1, in lieu of certain American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,Section XI, IWB-2500 requirements. Use of the proposed alternative will provide an acceptable level of quality and safety, as described in the enclosed request.
NMC requests authorization for use of Code Case N-613-1 by February 28, 2005 to support the upcoming Spring 2005 refueling outages at MNGP and DAEC.
This letter contains no new commitments and no revisions to existing commitments.
Edward J. Weinkam Director of Regulatory Services Nuclear Management Company, LLC Enclosure cc:
Administrator, Region III, USNRC Project Managers, DAEC, MNGP, USNRC Resident Inspectors, DAEC, MNGP, USNRC 700 First Street
- Hudson, Wisconsin 54016 Telephone: 715.377.3300
ENCLOSURE Duane Arnold Energy Center Monticello Nuclear Generating Plant Alternative to Use Code Case N-613-1
- 1. ASME Code Component(s) Affected Code Class:
Class 1
Reference:
ASME,Section XI Examination Category:
B-D Item Number:
B3.90
==
Description:==
Reactor Vessel Full Penetration Nozzle-to-Vessel Welds Component Numbers:
See Tables 1 and 2
2. Applicable Code Edition and Addenda
ASME Section Xl 1989 Edition, no Addenda is applicable to the Duane Arnold Energy Center (DAEC) Inservice Inspection (ISI) Program for the Third Ten-Year Interval.
ASME Section Xl 1995 Edition, 1996 Addenda is applicable to the Monticello Nuclear Generating Plant (MNGP) ISI Program for the Fourth Ten-Year Interval.
3. Applicable Code Requirement
Nuclear Management Company (NMC), LLC is currently required to perform inservice examinations of selected reactor vessel nozzle-to-vessel welds in accordance with the requirements of 10 CFR 50.55a, and the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components. Table IWB-2500-1, Examination Category B-D, Item No. B3.90 specifies the examination requirements. Figure IWB-2500-7(b) requires that a minimum volume of material, a distance of ts/2 (one half the reactor vessel shell thickness) adjacent to the weld, be examined.
4. Reason for Request
The required examination volume for the reactor vessel pressure retaining nozzle-to-vessel welds extends far beyond the weld into the base metal, and is unnecessarily large. This proposed alternative would re-define the examination volume boundary to 1/2 inch of base metal on each side of the widest portion of the weld, removing from examination the base metal that was extensively examined during prior inspections, and is not in the high residual stress region associated with the weld.
Page 1 of 6
5. Proposed Alternative and Basis for Use
Pursuant to 10 CFR 50.55a(a)(3)(i), authorization is requested to use the proposed alternative described in ASME Boiler and Pressure Vessel Code Section XI Code Case N-613-1 in lieu of the ASME Section XI Table IWB-2500-1 Examination Category B3.90 requirements. Compliance with the proposed alternative will provide an acceptable level of quality and safety for examination of the affected welds.
In lieu of the ts/2 volume requirement of ASME Section XI, Figure IWB-2500-7(b), NMC proposes to reduce the examination volume next to the widest part of the weld to one-half (1/2) inch from the weld. This refined examination volume is defined in detail within Code Case N-613-1. NMC will use Code Case N-613-1 for the Reactor Pressure Vessel (RPV) nozzles as shown in Figure 2 of the Code Case.
The required examination volume for the RPV nozzle-to-vessel welds extends far beyond the weld into the base metal, and is unnecessarily large. This proposed alternative would re-define the examination volume boundary to 1/2 inch of base metal on each side of the widest portion of the weld. This reduction in base metal inspection will not affect the flaw detection capabilities in the weld and heat affected zone. The proposed reduction in exam volume is base metal only.
The creation of flaws during plant service in the volume excluded from the proposed reduced examination is unlikely because of the low stress in the base metal away from the weld. The stresses caused by welding are concentrated at or near the weld.
Cracks, should they initiate, occur in the high-stressed areas of the weld. These high stress areas are contained in the volume that is defined by Code Case N-613-1 and are thus subject to examination. During previous examinations, no indications exceeding the allowable limits of the preservice or inservice criteria were found in the reactor vessel nozzle to shell examination volumes including the base metal areas proposed for exclusion from examination in this request. The prior thorough examination of the base metal and the examination of the high-stressed areas of the weld provide an acceptable level of quality and safety.
6. Duration of Proposed Alternative
This technical alternative will be used at DAEC during the current Third Ten-Year Interval of the Inservice Inspection Program scheduled to end on November 1, 2005, and at MNGP during the current Fourth Ten-Year Interval of the Inservice Inspection Program scheduled to end on May 31, 2012.
The use of Code Case N-613-1 is requested until the NRC publishes the Code Case in a future revision of Regulatory Guide 1.147.
Page 2 of 6
Table 1 DAEC Nozzle-to-Vessel Welds Within Scope of Request Summary Number Weld Identification and Description Nozzle Configuration Full Volume Exam Previously Completed to Extent Achievable Nondestructive Examination (NDE)
Method 008700 MSC-D001 Reactor Vessel Nozzle - Main Steam Code Case N-613-1 Figure 2 Examined in 1993 from RPV shell side only due to nozzle configuration; no recordable indications UT-0 UT-45 UT-60 008900 MSD-D001 Reactor Vessel Nozzle - Main Steam Code Case N-613-1 Figure 2 Examined in 1993 from RPV shell side only due to nozzle configuration; no recordable indications UT-0 UT-45 UT-60 005800 FWB-D001 Reactor Vessel Nozzle - Feed Water Code Case N-613-1 Figure 2 Examined in 1996 with General Electric Reactor Inspection System (GERIS); no recordable indications UT-0 UT-45 UT-60 006300 FWC-D001 Reactor Vessel Nozzle - Feed Water Code Case N-613-1 Figure 2 Examined in 1996 with GERIS; no recordable indications UT-0 UT-45 UT-60 006800 FWD-D001 Reactor Vessel Nozzle Code Case N-613-1 Figure 2 Examined in 1996 with GERIS.
One indication was recorded with the 45° T-scan exam that required evaluation per ASME Code Section XI, 1980 Edition, Winter 1981 Addenda and Regulatory Guide 1.150 and was found to be acceptable.
UT-0 UT-45 UT-60 010900 RRG-D001 Reactor Vessel Nozzle - Recirc.
System Riser Code Case N-613-1 Figure 2 Examined in 1993; no recordable indications UT-0 UT-45 UT-60 007900 JPB-D001 Reactor Vessel Nozzle - Jet Pump Instrumentation Code Case N-613-1 Figure 2 Examined in 1993; no recordable indications UT-0 UT-45 UT-60 008100 LCA-D001 Reactor Vessel Nozzle Code Case N-613-1 Figure 2 Examined in 1993; no recordable indications UT-0 UT-45 UT-60 011500 VIB-D001 Reactor Vessel Nozzle Code Case N-613-1 Figure 2 Examined in 1993; no recordable indications UT-0 UT-45 UT-60 Page 3 of 6
Table 2 MNGP Nozzle-to-Vessel Welds Within Scope of Request Summary Number Weld Identification and Description Nozzle Configuration Full Volume Exam Previously Completed to Extent Achievable Nondestructive Examination (NDE)
Method 102652 N-1A NV, RPV N-1A Nozzle, Recirc Suction Code Case N-613-1, Figure 2 Examined in 1994 from RPV shell side only due to nozzle configuration; no recordable indications.
UT-0 UT-45 UT-60 102654 N-1B NV, RPV N-1B Nozzle, Recirc Suction Code Case N-613-1, Figure 2 Examined in 2001 from RPV shell side only due to nozzle configuration; no recordable indications.
UT-0 UT-45 UT-60 102656 N-2A NV, RPV N-2A Nozzle, Recirc Riser Inlet Code Case N-613-1, Figure 2 Examined in 2001 from RPV shell side only due to nozzle configuration; no recordable indications.
UT-0 UT-45 UT-60 102658 N-2B NV, RPV N-2B Nozzle, Recirc Riser Inlet Code Case N-613-1, Figure 2 Examined in 2001 from RPV shell side only due to nozzle configuration; no recordable indications.
UT-0 UT-45 UT-60 102660 N-2C NV, RPV N-2C Nozzle, Recirc Riser Inlet Code Case N-613-1, Figure 2 Examined in 2000 from RPV shell side only due to nozzle configuration; no recordable indications.
UT-0 UT-45 UT-60 102662 N-2D NV, RPV N-2D Nozzle, Recirc Riser Inlet Code Case N-613-1, Figure 2 Examined in 1994 from RPV shell side only due to nozzle configuration; no recordable indications.
UT-0 UT-45 UT-60 102664 N-2E NV, RPV N-2E Nozzle, Recirc Riser Inlet Code Case N-613-1, Figure 2 Examined in 1994 from RPV shell side only due to nozzle configuration; no recordable indications.
UT-0 UT-45 UT-60 102666 N-2F NV, RPV N-2F Nozzle, Recirc Riser Inlet Code Case N-613-1, Figure 2 Examined in 2000 from RPV shell side only due to nozzle configuration; no recordable indications.
UT-0 UT-45 UT-60 102668 N-2G NV, RPV N-2G Nozzle, Recirc Riser Inlet Code Case N-613-1, Figure 2 Examined in 1998 from RPV shell side only due to nozzle configuration; no recordable indications.
UT-0 UT-45 UT-60 102670 N-2H NV, RPV N-2H Nozzle, Recirc Riser Inlet Code Case N-613-1, Figure 2 Examined in 1998 from RPV shell side only due to nozzle configuration; no recordable indications.
UT-0 UT-45 UT-60 102672 N-2J NV, RPV N-2J Nozzle, Recirc Riser Inlet Code Case N-613-1, Figure 2 Examined in 1994 from RPV shell side only due to nozzle configuration; no recordable indications.
UT-0 UT-45 UT-60 102674 N-2K NV, RPV N-2K Nozzle, Recirc Riser Inlet Code Case N-613-1, Figure 2 Examined in 2001 from RPV shell side only due to nozzle configuration; no recordable indications.
UT-0 UT-45 UT-60 Page 4 of 6
Summary Number Weld Identification and Description Nozzle Configuration Full Volume Exam Previously Completed to Extent Achievable Nondestructive Examination (NDE)
Method 102676 N-3A NV, RPV N-3A, Main Steam Outlet Code Case N-613-1, Figure 2 Examined in 1994 from RPV shell side only due to nozzle configuration; no recordable indications.
UT-0 UT-45 UT-60 102678 N-3B NV, RPV N-3B, Main Steam Outlet Code Case N-613-1, Figure 2 Examined in 2000 from RPV shell side only due to nozzle configuration; no recordable indications.
UT-0 UT-45 UT-60 102680 N-3C NV, RPV N-3C, Main Steam Outlet Code Case N-613-1, Figure 2 Examined in 1998 from RPV shell side only due to nozzle configuration; One indication was recorded with the 60° scan which required evaluation per ASME Code Section XI, 1986 Edition with no Addenda and was found to be acceptable. Indication is contained within the reduced volume of Code Case N-613-1, Figure 2.
UT-0 UT-45 UT-60 102682 N-3D NV, RPV N-3D, Main Steam Outlet Code Case N-613-1, Figure 2 Examined in 2000 from RPV shell side only due to nozzle configuration; no recordable indications.
UT-0 UT-45 UT-60 102684 N-4A NV, RPV N-4A, Feedwater Inlet Code Case N-613-1, Figure 2 Examined in 1996 from RPV shell side only due to nozzle configuration; no recordable indications.
UT-0 UT-45 UT-60 102686 N-4B NV, RPV N-4B, Feedwater Inlet Code Case N-613-1, Figure 2 Examined in 1998 from RPV shell side only due to nozzle configuration; no recordable indications.
UT-0 UT-45 UT-60 102688 N-4C NV, RPV N-4C, Feedwater Inlet Code Case N-613-1, Figure 2 Examined in 1994 from RPV shell side only due to nozzle configuration; no recordable indications.
UT-0 UT-45 UT-60 102690 N-4D NV, RPV N-4D, Feedwater Inlet Code Case N-613-1, Figure 2 Examined in 2000 from RPV shell side only due to nozzle configuration; no recordable indications.
UT-0 UT-45 UT-60 102692 N-5A NV, RPV N-5A, Core Spray Inlet Code Case N-613-1, Figure 2 Examined in 2000 from RPV shell side only due to nozzle configuration; no recordable indications.
UT-0 UT-45 UT-60 102694 N-5B NV, RPV N-5B, Core Spray Inlet Code Case N-613-1, Figure 2 Examined in 1994 from RPV shell side only due to nozzle configuration; no recordable indications.
UT-0 UT-45 UT-60 102375 N-6A NV, RPV N-6A, Spare (formerly Reactor Vessel Head Spray)
Code Case N-613-1, Figure 2 Examined in 1996 from RPV shell side only due to nozzle configuration; no recordable indications.
UT-0 UT-45 UT-60 102377 N-6B NV, RPV N-6B, Spare Code Case N-613-1, Figure 2 Examined in 2000 from RPV shell side only due to nozzle configuration; no recordable indications.
UT-0 UT-45 UT-60 Page 5 of 6
Summary Number Weld Identification and Description Nozzle Configuration Full Volume Exam Previously Completed to Extent Achievable Nondestructive Examination (NDE)
Method 102379 N-7 NV, RPV N-7, Reactor Vessel Head Vent Code Case N-613-1, Figure 2 Examined in 1998 from RPV shell side only due to nozzle configuration; no recordable indications.
UT-0 UT-45 UT-60 102696 N-8A NV, RPV N-8A, Jet Pump Instrumentation Code Case N-613-1, Figure 2 Examined in 1994 from RPV shell side only due to nozzle configuration; no recordable indications.
UT-0 UT-45 UT-60 102698 N-8B NV, RPV N-8B, Jet Pump Instrumentation Code Case N-613-1, Figure 2 Examined in 2001 from RPV shell side only due to nozzle configuration; no recordable indications.
UT-0 UT-45 UT-60 102700 N-9 NV, RPV N-9, Spare (formerly CRD Return)
Code Case N-613-1, Figure 2 Examined in 1996 from RPV shell side only due to nozzle configuration; no recordable indications.
UT-0 UT-45 UT-60 102623 N-10 NV, RPV N-10, Standby Liquid Control Injection Code Case N-613-1, Figure 2 Examined in 2000 from RPV shell side only due to nozzle configuration; no recordable indications.
UT-0 UT-45 UT-60 Page 6 of 6