ML18039A764
| ML18039A764 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 04/29/1999 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML18039A763 | List: |
| References | |
| NUDOCS 9905040322 | |
| Download: ML18039A764 (7) | |
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uglTED STATEs NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 SAFETY EVALUATIONBYTHE OFFICE OF NUCLEAR REACTOR REGULATION RELATEDTO THE RELIEF FROM CERTAIN RADIOGRAPHIC RE UIREMENTS BROWNS FERRY NUCLEAR PLANT UNITS 2 AND 3 TENNESSEE VALLEYAUTHORITY DOCKET NOS. 50-260 AND 50-296
1.0 INTRODUCTION
In a letter dated April27, 1999, the Tennessee Valley Authority (TVA)submitted a request for relief from certain radiographic image-quality requirements at Browns Ferry Nuclear Plant (BFN), Units.2 and 3. TVAproposed an alternative to the plaque-type penetrameters required by the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (Code). The proposed alternative is to use wire penetrameters in radiographic inspections.
Penetrameters are image quality indicators (IQls) used to ensure that the desired sensitivity, definition, and contrast has been achieved in radiographic examination of materials.
2.0 BACKGROUND
Pursuant to 10 CFR 50.55a(g)(4), ASME Code Class 1, 2 and 3 components (including supports) must meet the requirements, except design and access provisions and preservice examination requirements, set forth in Section XI of editions of the Code and Addenda that become effective subsequent to the editions specified in paragraphs (g)(2) and (g)(3) of this section and that are incorporated by reference in paragraph (b) of this section, to the extent practical within the limitations of design, geometry and materials of construction of the components.
2.1 Code Re uirements The applicable ASME Section XI Code for the BFN, Unit 2 Second 10-Year Inservice Inspection (ISI) interval is the 1986 Edition with no addenda.
For Unit,3 the Code of record for the Second 10-Year Inservice Inspection (ISI) interval is the 1989 Edition with no addenda.
In a submittal dated March 9, 1995, TVAproposed to use ASME Code Case N-416-1, "Alternate Pressure Test Requirement for Welded Repairs or Installation of Replacement Items by Welding, Class 1, 2, and 3,Section XI, Division 1," for Units 2 and 3.
990S040322 990429 PDR ADOCK 05000260 P
PDR Enclosure
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f TVA's proposed alternative to the Code was authorized in a letter from the U.S. Nuclear Regulatory Commission (NRC) dated August 18, 1995. Specifically, TVAwas authorized to use ASME Code Case N-416-1. This code case requires that non-destructive examination of welds be performed in accordance with the applicable Subsection of the 1992 Edition of Section III of the Code.
The use of penetrameters are contained in paragraphs NB-5111 and NC-5111 to Section III of the 1992 Edition of the Code, that state in part "...Radiographic examination shall be in accordance with Section V, Article 2, except that... the penetrameters of Table NB-5111-1 (and NC-5111-1) shall be used in lieu of those shown in Table T-276" [ofSection V].
2.2 Re uestfor Relief Pursuant to 10 CFR 50.55a(a)(3), proposed alternatives to the requirements of paragraphs (c),
(d), (e), (f), (g), and (h) of this section or portions thereof may be used when authorized by the Director of the Office of Nuclear Reactor Regulation. The applicant shall demonstrate that:
(i) the proposed alternatives would provide an acceptable level of quality and safety, or (ii) compliance with the'specified requirements of this section would result in hardship of unusual difficultywithout a compensating increase in the level of quality and safety.
TVA has requested relief from the penetrameter requirements in paragraphs NB-5111 and NC-5111 to Section III of the 1992 Edition of the Code.
2.3 Basis for Relief TVA believes that plaque-type penetrameters are difficultto use due to their physical placement and radiograph characteristics.
The placement of flat plaques on curved surfaces of pipe components usually need some form of shimming. After positioning the plaque on test material and performing a radiographic examination, the recorded radiographic characteristics of the essential T hole is often obscured or distorted due to specimen anomalies, part geometry,.or film artifacts outside the area of interest. These difficulties create re-shoot conditions.
The remakes have an adverse as-low-as-reasonably-achievable impact due to the additional radiation exposure to the radiography crew.
TVAbelieves that the wire-type IQI is superior to the plaque-type IQI for nuclear piping component applications.
Wire IQls can be placed directly across the area of interest, thus encompassing the object's range of density and geometry.
The 1-inch minimum length of the essential IQI wire eliminates the problem of indicator loss due to distortion, anomalies, and part geometry.
The wire-type IQls provide the same function as the plaque-type penetrameters by indicating a change in thickness and spatial resolution of the image without the use of shim blocks and pipe standards.
Wire IQls have been shown to provide quality and sensitivity equivalent to plaque-type penetrameters as documented in Table 4 of American Society for Testing and Materials (ASTM) E747-87 and ASME Section V, Article 22, Standard SE-747.
Because of the equivalent sensitivity, the proposed testing alternative to use wire IQls provides equivalent testing results to the current plaque-type IQls. Therefore, the quality of the inspection and resulting safety of the plant, based on the inspection results, are not impacted by this proposed alternative, thus providing an acceptable level of quality and safety.
3.0 EVALUATION 3.1 Pro osed Alternative Examination TVAproposes to use wire-type IQls for radiography examinations as provided for in ASME Code,Section III, 1992 Edition with 1993 Addenda.
3.2 Discussion Volume 17 of the Ninth Edition of the Metals Handbook, published in 1989, states that wire-type penetrameters are widely used in Europe, and a standard design is used in the United Kingdom, Germany, the Netherlands, and Scandinavia and by the International Organization for Standardization and the International Institute of Welding. The handbook goes on to state that wire penetrameters specified in ASTM E 747-87 are widely used in the United States.
ASTM d veloped this specification using a public forum with approval by public consensus.
The ASTM Standard E 747-87 referenced in the Metals Handbook is identical to the 1989 Edition of ASME's Standard SE-747-87.
Wire penetrameters were not included in Section III of the Code until the 1992 Edition with 1993 Addenda.
Although the 1992 Edition with 1993 Addenda of the Code has not been endorsed at this time by NRC, itwas developed through the consensus building process used by Section.lll of the Code.
The NRC participates in these forums.
In the staff's review of TVA's proposed alternativ, the staff assembled a table, similar to the proposed alternative, by merging like data from Table 4 to SE-747 to Section V with Table NB-5111-1 (NC-5111-1) to Section III of the 1992 Edition of Code.
The penetrameters from the newly-created wire/plaque table were compared against the penetrameters from Table NB-5111-1 (NC-5111-1) to Section III of the 1992 Edition with 1993 Addenda of the Code.
This comparison showed that the wire diameters in the newly-created table are equal to or slightly smaller than wire diameters in Table NB-5111-1 (NC-511-1) to the 1992 Edition with 1993 Addenda of the Code.
This comparison by the staff provides adequate technical assurance that the wire penetrameters listed in Table NB-5111-1 (NC-5111-1) in the ASME Code,Section III, 1992 Edition with 1993 addenda, willprovide an acceptable level of quality and safety.
4.0 CONCLUSION
Based on the above evaluation, the staff concludes that the proposed alternative to use IQls for radiography examinations as provided for in ASME Section III, 1992 Edition with 1993 Addenda, provides an acceptable level of quality and safety. Therefore, the staff authorizes the use of the proposed alternative pursuant to 10 CFR 50.55a(a)(3)(i).
Principal Contributor. David Naujock, NRR Dated: April 29, 1999
Mr. J. A. Scalice Tennessee Valley Authority BROWNS FERRY NUCLEAR PLANT CC:
Senior Vice President Nuclear Operations Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Jack A. Bailey, Vice President Engineering &Technical Services Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Karl W. Singer, Site Vice President Browns Ferry Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Decatur, AL 35609 General Counsel Tennessee Valley Authority ET 10H 400 West Summit Hill Drive Knoxville, TN 37902 Mr. N. C. Kazanas, General Manager Nuclear Assurance Tennessee Valley Authority 5M Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Robert G. Jones, Plant Manager Browns Ferry Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Decatur, AL 35609
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Mr. Mark J. Burzynski, Managar Nuclear Licensing Tennessee Valley Authority 4X Blue Ridge 1101 Market Street Chattanooga, TN 37402-2801 Mr. Timothy E. Abney, Manager Licensing and Industry Affairs Browns Ferry Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Decatur, AL35609 Senior Resident Inspector U.S. Nuclear Regulatory Commission Browns Ferry Nuclear Plant I0833 Shaw Road Athens, AL35611 State Health Officer Alabama Dept. of Public Health 434 Monroe Street Montgom'ery, AL36130-170l Chairman Limestone County Commission 310 West Washington Street Athens, AL 35611
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