ML20057D603
| ML20057D603 | |
| Person / Time | |
|---|---|
| Site: | Duane Arnold  |
| Issue date: | 09/24/1993 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20057D599 | List: |
| References | |
| NUDOCS 9310050035 | |
| Download: ML20057D603 (5) | |
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NUCLEAR REGULATORY COMMISSION l
d WASHINGTON D.C. 20555-0001 Enclosure gw SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION OF THE SECOND TEN-YEAR INTERVAL INSERVICE INSPECTION RE0 VESTS FOR RELIEF FOR IOWA ELECTRIC LIGHT AND POWER COMPANY DUANE ARN0LD ENERGY CENTER DOCKET NO. 50-331
1.0 INTRODUCTION
The Technical Specifications for Duane Arnold Energy Center state that the inservice inspection and testing of 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)(1).
Part 50.55a(a)(3) of 10 CFR 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, 2, and 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 raaterials of construction of the components. The regulations require that inservice examination of components and system pressure tests conducted during the second 10-year interval comply with the requirements in the latest edition and addenda of Section XI of the ASME Code incorporated by reference in 10 CFR 50.55a(b) on the date twelve months prior to the start of the 120-month inspection interval, subject to the limitations and modifi-cations listed therein. The applicable edition of Section XI of the ASME Code for Duane Arnold Energy Center's second 10-year inservice inspection (ISI) interval is the 1980 Edition, through Winter 1981 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.
Pursuant to 10 CFR 50.55a(g)(5), if the licensee determines that conformance with an examination requirement of Section XI of the ASME Code is not i
practical for its facility, information shall be submitted to the Commission l
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)(1), the Commission may grant relief and may impose 9310050035 930924 PDR ADDCK 05000331 p
PDR l
alternative requirements that are determined to be authorized by law, will not 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.
In a letter dated January 29, 1993, the licensee, Iowa Electric Light and Power Company, submitted two new relief requests for the second 10-year ISI interval and a revision of a previous relief request. As a result of a conference call held on July 28, 1993, the licensee submitted drawings in a letter dated August 5,1993.
Evaluation of the relief requests is contained in the following section.
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 support of the submitted relief requests as follows:
A.
Reauest for Relief No. NDE-005. Revision 1. Examination Cateaories C-C and F-C. Items C3.20. F3.10. F3.20. F3.30 and F3.40. HPCI Pumo Discharae Intearal Attachments and Component Supports Code Reauirement: Table IWC-2500-1, Examination Category C-C, Item C3.23 requires a 100% surface examination for integral attachments to piping as defined by IWC-2500-5.
Examinations are limited to those attachments required to be examined under Examination Categories C-F and C-G.
Table IWF-2500-1, Examination Category F-C, Items F3.10, F3.20, F3.30 and F3.40 require a VT-3 visual examination as defined by IWF-2500-1.
Components selected for examination shall be the supports of components that are required to be examined under IWB, IWC, IWD, and i
IWD.
For multiple components within a system of similar design, function, and service, the supports of only one of the multiple components are required to be examined.
Licensee's Code Relief Recuest: Relief is requested from performing the Code-required surface and VT-3 visual examinations for HPCI pump discharge supports HPB-CE-069 (EBB-5-SR-9) and HPB-CE071 (EBB-5-H-12).
Relief from the surface and visual examinations of eight lugs on Support HPB-CE-68 was previously granted in an NRC SER dated July 7, 1987.
Licensee's Basis for Reouestina Relief: The licensee states that the supports are trapeze supports for vertical sections of piping and are located in a penetration. The location of the supports makes them inaccessible for performing a surface or visual examination.
Licensee's Proposed Alternative Examination: None. However, the upstream and downstream supports will be examined in accordance with the Code.
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Staff Evaluation: The subject component supports and attachment welds require visual and surface examination. However, the areas requiring examination are located in a penetration and are inaccessible.
Therefore, the Code requirements are impractical.
In order to perform the examination to the extent required by the Code, the subject penetrations would require design modification to allow access for examination. Considering that the adjacent supports will be examined as required by the Code, generic degradation will be detected.
Therefore, pursuant to 10 CFR 50.55a(g)(6)(1), relief is granted as requested.
B.
Reauest for Relief No. NDE-011. Examination Cateaory C-C. Item C3.20.
Intearal Attachment Weld to Class 2 Pipino Code Reouirement: Table IWC-2500-1, Examination Category C-C, Item C3.20, requires a 100% surface examination of integrally welded attachments to piping as defined by IWC-2500-5.
Examination is limited to attachment welds of those components required to be examined under Examination Category C-F and C-G.
Licensee's Code Relief Reauest:
Relief is requested from performing the surface examination of the integral attachment welds for Hanger Support RHA-CE099 (HBB-24-H-10-1) to the extent required by the Code.
Licensee's Basis for Recuestino Relief: The licensee states that the support does not allow access to the entire length of weld as required for the Code examination.
In order to perform the Code-required examination on the lower 20% of each weld, the piping system would have to be elevated and supported while the examination was performed.
The dose rates in this area are 15 to 20 mrem / hour. The benefit of examining the lower 20% of the weld has only a small potential of increasing plant safety margins and a very disproportionate impact on expenditures of plant manpower and radiation exposure.
Licensee's Proposed Alternative Examination: None. The Code-required surface examination will be performed to the maximum extent practical (approximately 80%).
1 Staff Evaluation: The Code requires a 100% surface examination of the subject integral attachment welds. However, it is evident from the drawings provided by the licensee that the design of the support makes
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the surface examination impractical to perform to the extent required i
by the Code. Therefore, the Code requirement is impractical.
In order to perform the Code-required surface examination of the entire i
length of weld, the support would require design modifications to allow access for examination. Considering that a significant portion (80%) of the Code-required examination is being performed and the impracticality of meeting the Code requirements, relief is granted pursuant to 10 CFR 50.55a(g)(6)(i).
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C.
Reouest for Relief No. RR-001. Paraoraoh IWA-4120. Additional Rules and Reouirements for Reoair Procedures Code Reouirement:
Paragraph IWA-4120, Additfonal Rules and Requirements under Article IWA-4000, Repair Procedures states that repairs shall be performed in accordance with the Owner's Design Specification and Construction Code of the component or system.
Later editions of the Construction Code or of Section III, either in the entirety or portions thereof, may be used.
If repair welding cannot be performed in accordance with these requirements, the following Section XI requirements may be used:
(a) IWB-4000 for Class I components (b) IWC-4000 for Class 2 components (c) IWD-4000 for Class 3 components (d) IWE-4000 for Class MC components licensee's Code Relief Recuest:
Relief is requested to use Nonmandatory Appendix A, Analysis of flas Indications, of ASME Section XI in lieu of the acceptance criteria of the construction code or Section III for Class 1, 2, and 3 valves.
Based on the limitations of Appendix A, this request is limited to ferritic valves only.
Licensee's Basis for Recuestino Relief: The licensee states that when performing repairs / replacements of valve seats and guiding surfaces that include the addition of pressure retaining material or hardfacing by welding, the construction code does not allow linear indications.
Removing such indications may reveal fabrication flaws (i.e., casting defects) that are beyond the repair / replacement area.
This could result in a major repair effort, increasing manpower, costs, scheduling, and exposure.
In lieu of using the construction code acceptance criteria for these instances, an ASME Section XI Appendix A evaluation may be performed to bound the flaw and determine acceptability. These flaws will be subsequently examined as specified in each evaluation.
If the evaluation provides acceptability for the remaining life of the component, then the subsequent examination will only be performed when the valve is opened for. reasons other than performing examination.
If the evaluation provides acceptability for a period of time less than the remaining life of the plant, periodic examinations shall be performed based on the evaluation results.
Licensee's Proposed Alternative Examination:
Indications that are found when performing repairs / replacements of valve seats and guiding surfaces and that do not meet the construction code acceptance criteria may be evaluated per ASME Section XI Appendix A to determine acceptability. Subsequent examinations shall be specified in the evaluation.
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Staff Evaluation: The Code requires that repairs be performed in accordance with the Owner's Design Specification and the Construction o
Code of that component or system. As an alternative to this requirement, the Licensee is requesting relief to use Nonmandatory Appendix A of Section XI in lieu of the acceptance criteria of the construction code for indications found during repair procedures.
Paragraph TWB-3122.4, Acceptance by Evaluation, of Section XI states that components whose examinations reveal flaw indications that exceed the acceptance standards listed in Table IWB-2500-1 shall be accept-able for service without the flaw removal, repair, or replacement if an evaluation analysis meets the acceptance criteria as described in IWB-3600.
IWB-3600 refers to Appendix A as an acceptable method for performing the evaluation. Thus, the use of Appendix A is acceptable for indications found with nondestructive examination techniques.
However, the licensee is requesting generic relief to use Appendix A for fabrication flaws uncovered during repair procedures. The staff has reviewed the issues in this request and has determined that Appendix A is not applicable for indications uncovered by repair procedures, and that fabrication flaws found in this manner should be evaluated and repaired as required by the applicable construction code. Therefore, relief is denied.
If relief is warranted for certain, specific cases, the licensee should submit a new request containing justification supporting the impracticality of meeting the acceptance criteria of the construction code. These requests will be evaluated by the staff on a case-by-case basis.
3.0 CONCLUSION
Section 50.55a(g)(4) of 10 CFR requires that components (including supports) that are classified as ASME Code Class 1, 2, and 3 meet the requirements, except design and access provisions and preservice requirements, set forth in anplicable editions of ASME Section XI to the extent practical within the limitacions of design, geometry, and materials of construction of the components.
Pursuant to 10 CFR 50.55a(g)(5)(iii), the licensee determined that conformance with certain Code requirements is impractical for its facility and submitted supporting information. The staff has reviewed the licensee's submittal and has concluded that in some cases, relief can be granted as requested.
Pursuant to 10 CFR 50.55a(g)(6)(1), the staff concludes that the requirements of the Code are impractical and relief may be granted for request for relief NDE-005 and NDE-Oll. 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 fac'Oity.
Request for relief RR-001 is denied. The staff has concluded that Appendix A is not applicable for fabrication flaws uncovered by repair procedures, and that the acceptance criteria of the construction code should be used.
Principal Cor.tributor:
T. McLellan Date: September 24, 1993