ML20135A284
| ML20135A284 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 11/22/1996 |
| From: | Kraft E COMMONWEALTH EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| ESK-96-211, NUDOCS 9612030150 | |
| Download: ML20135A284 (5) | |
Text
Onnmonw calth lihwn Osmpany Qtud Gtics Generating Nation I
22710 2&ith Avenue North Oerdos a, 11 61242 9740 Tcl 9 9451 2211 ESK-96-211 November 22,1996 United States Nuclear Regulatory Commission Washington, D.C. 20555 Attention:
Document Control Desk
Subject:
Quad Cities Nuclear Power Station Unit 1 Results Of Augmented Examination Of The RPV Shell Welds And Relief Request Pursuant To 10 CFR 50.55a(g)(6)(ii)( A)
NRC Docket No. 50-265
Reference:
(1)
Bob Rybak, Comed to U.S. Nuclear Regulatory Commision letter dated January 4,1996 Comed conducted an augmented examination of the Reactor Pressure Vessel (RPV) shell welds pursuant to the requirements stipulated in 10 CFR 50.55a(g)(6)(ii)(A).
Subsection 6(ii)(A)(5) requires licensees that are unable to completely satisfy the augmented RPV shell weld examination requirement to submit information to the Commission to support such determination and propose alternatives to the examination requirements that would provide an acceptable level of quality and safety.
i This letter provides the shell weld examination results (reference (1)) and requests l
relief from examination of certain reactor vessel shell welds pursuant to I
50.55a(g)(6)(ii)(A)(5) in Attachment A.
Respectfully, 8
Q E. S. Kraft, Jr.
Site Vice President Quad Cities Station Attachment (A), Relief Request Number: CR-18 (4 pages) cc:
A. B. Beach, Regional Administrator, Region III R. M. Pulsifer, Project Manager, NRR i
C. G. Miller, Senior Resident Inspector, Quad Cities p
i D. C. Tubbs, MidAmerican Energy Company R. J. Singer, MidAmerican Energy Company F. A. Spangenberg, Regulatory Affairs Manager, Dresden g' d g' j g C. C. Peterson, Regulatory Affairs Manager, Quad Cities DCD License (both electronic and hard copies) 9612030150 961122 PDR ADOCK 05000265
~
G PDR
l Quad Cities Station 3rd Interval Inservice Inspection Plan RELIEF REQUEST NUMBER: CR-18 (Page 1 of 4)
COMPONENT IDENTIFICATION Code Class:
1
References:
IWB-2500 Table IWB-2500-1 Examination Category:
B-A Item Number:
Bl.10
==
Description:==
Examination of RPV shell welds CODE REOUIREMENT IWB-2500 states that components shall be examined and tested as specified in Table IWB-2500-1.
Table IWB-2500-1, Category B-A, Item Bl.10 requires a volumetric examination to be performed on the Reactor Pressure Vessel shell welds each inspection interval.
BASIS FOR RELIEF l
Pursuant to 10 CFR 50.55a(g)(6)(ii)(A)(5), relief is requested on the basis that the alternate method of examination and the achieved weld coverage provide an acceptable level of quality and safety.
The RPV was examined from the internal surface to the extent practical with an alternate method which is qualified to the highest standard available. Further examination from the inside surface is not practical without disassembly of vessel internal components. For weld areas that could not be examined from the inside surface, examination from the outside surface was evaluated. The exterior vessel surface ls covered with permanent insulation located in close proximity to the RPV outside surface. The lower exterior vessel surface is also covered with a stmetural steel bioshield wall. Access is limited to nozzle and inspection port penetrations in the insulation and bioshield wall. It was determined that supplemental manual examination from the outside surface were not practical due to the bioshield wall, insulation, and dose considerations.
The RPV shell weld examinations confirmed no flaws in the vessel, even though greater than 90% coverage was not attained for all RPV shell welds. Performing additional examinations to achieve the greater than 90% coverage presents hardship and would incur unnecessary radiological exposure and requires RPV internal, RPV bioshield, or insulation disassembly.
Since the examination results confirm that there are no flaws, the underlying objectives of the augmented examination requirements have been met. Additionally, a VT-2 examination j
10-40 Revision 0
Quad Cities Station 3rd Interval Inservice Inspection Plan RELIEF REQUEST NUMBER: CR-18 (Page 2 of 4)
BASIS FOR RELIEF (Con't) performed on the RPV during system pressure test per examination category B-P each refueling outage provides additional assurance that the structural integrity of the subject welds is maintained. For these reasons, Comed requests relief from additional augmented examination of l
PROPOSED ALTERNATE EXAMINATION a
The shell welds of the RPV were ultrasonically examined remotely from the inside of the vessel to the extent practical. Personnel performing the examinations were certified to the requirements j
of the 1989 Edition of ASME Section XI. The remote examinations were performed in accordance with an examination procedure developed by General Electric. This procedure was i
demonstrated at the " Performance Demonstration Initiative" (PDI) qualification in accordance with the 1992 edition 1993 addenda of ASME Section XI, Appendix VIII requirements. The procedure does not comply with ASME Section XI 1989 Edition, paragraph IWA-2232; ASME 1
2 Section V Article 4; or NRC Regulatory Guide 1.150 and, as such, is considered an alternate examination technique. This procedure was made available to the NRC Inspectors during the examinations.
The use of PDI qualified procedures results in a more sensitive examination for the detection of potential flaws than the Code described techniques. The error band for sizing has been established within the limits of Appendix VIII. This examination method's capability to reliably i
detect flaws in areas of restricted access was satisfactorily demonstrated at PDI Session No. 61-02.
i l
Table 1 presents the weld specific examination coverage achieved and associated interferences.
Figure 1 shows the weld seams examined by the GERIS 2000.
The examination identified 53 indications, all of which were within the applicable acceptance 3
standards of subarticle IWB-3500 of ASME Section XI. These indications are concluded to be f
from small acceptable flaws created at RPV fabrication.
I APPLICABLE TIME PERIOD Relief is requested for the third ten-year interval of the Inservice Inspection Program for Quad Cities Unit 1, which concludes on February 18, 2003.
1 i
10-41 Revision 0
Tr:ble 1: Quad Cities Nuclear Power Station Unit 1 RPV Augmented Ermination Results
% Total W eld Length Volume Number of Comed Weld Code Relief **
Length Scanned Coverage Flaws identification item Requested (in)
(in)
Achieved identified Limitations RPV-CW-C3C4 B1.11 NO 790.1 753.8 95.4 %
27 Guide Rods at 0* and 180* Azimuths Surveillance Specimen Brackets; Nozzles N9-A B12-A, and N12-RPV-CW-C2C3 B1.11 YES 790.1 564.1 71.4 %
2 B
Surveillance Specimen Brackets; Jet Pump Riser Braces; Guide RPV-CW-C1C2 B1.11 YES 790.1 416.4 52.7%
12 Rods at 20* and 200* Azimuth; Core Spray Piping RPV-CW-LHC1 B1.11 YES 790.1 0.0 0.0%
n/a Manipulator lower scan limit RPV-VSC4-99 B1.12 NO 129.9 129.9 100.0 %
0 RPV-VSC4-219 81.12 YES 129.9 102.6 79.0 %
0 Steam Dryer support Bracket; Nozzle N11-B RPV-VSC4-261 B1.12 NO 129.9 129.9 100.0%
0 RPV-VSC4-339 B1.12 NO 129.9 129.9 100.0%
0 RPV-VSC3-77 B1.12 YES 133.0 29.5 22.2 %
2 Feedwater Spargers; Core Spray Piping RPV-VSC3-197 B1.12 YES 133.0 30.9 23.2 %
0 Feedwater Spargers; Core Spray Piping; Guide Rod at 200*
RPV-VSC3-317 B1.12 YES 133.0 95.8 72.0 %
0 Feedwater Spargers; Core Spray Piping RPV-VSC2-22 B1.12 YES 133.0 73.9 55.6 %
3 Jet Pump Riser Braces; Guide Rod at 20* Azimuth RPV-VSC2-141 B1.12 NO 133.0 133.0 100.0 %
5 RPV-VSC2-261 B1.12 YES 133.0 73.9 55.6 %
0 Jet Pump Riser Braces RPV-VSC2-323 B1.12 NO 133.0 133.0 100.0 %
1 RPV-VSC1-55 B1.12 YES 133.0 114.0 85.7 %
1 Manipulator lower scan limit; Nozzle N2-C RPV-VSC1-77 B1.12 YES 133.0 0.0 0.0%
n/a Core Spray piping RPV-VSC1-197 B1.12 YES 133.0 0.0 0.0%
n'a Guide Rod at 200* Azimuth RPV-VSC1-317 B1.12 YES 133.0 114.0 85.7 %
0 Manipulator lower scan limit; Nozzle N2-K
- Based on 90% Volume Coverage
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