ML20205Q622

Safety Evaluation Authorizing Proposed Alternative to Use Wire Penetrameters for ISI Radiography in Place of ASME Code Requirement

ML20205Q622
Person / Time
Site:	San Onofre
Issue date:	04/19/1999
From:	NRC (Affiliation Not Assigned)
To:
Shared Package
ML20205Q620	List: ML20205Q617 ML20205Q622
References
NUDOCS 9904210331
Download: ML20205Q622 (4)

Text

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pucc e" 4 UNITED STATES g g NUCLEAR REGULATORY COMMISSION i

'C WASHINGTON, D.C. 20666-0001

,o SAFETY EVALUATION BY THE OFFICE % NUCLEAR REACTOR REGULATION RELATED TO RELIEF FROM CERTAIN RADIOGRAPHIC REQUIREMENTS SOUTHERN CALIFORNIA EDISON COMPANY SAN ONOFRE NUCLEAR GENERATING STATION. UNITS 2 AND 3 DOCKET NOS. 50-361 AND 50-362

1.0 INTRODUCTION

in a letter dated August 26,1998, Southern California Edison Company (SCE or the licensee) submitted a request for relief from certain radiographic image-quality requirements at San ,

Onofre Nuclear Generating Station (SONGS), Units 2 and 3. The licensee proposed 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 (101) 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 Requirements The applicable edition of Section XI of the Code for SONGS Units 2 and 3, for the second 10-year inservice inspection (ISI) interval is the 1989 Edition with no addenda. In a submittal dated December 6,1994, SONGS proposed an alternative to the Code that was authorized in a letter from the NRC dated January 11,1995. Specifically, SONGS was authorized to use ASME Code Case N-416-1. This Code Case requires that non-destructive testing (NDE) of welds be performed in accordance with the applicable Subsection of the 1992 Edition of Section lli of the Code. This authorization extends until such time as the Code Case is published in a future revision of Regulatory Guide (RG) 1.147, " Inservice inspection Code Case Acceptability -

ASME Section XI, Division 1." If the licensee continues using the Code Case, the licensee is to follow all provisions in ASME Code Case N-416-1, with limitations issued in Regulatory Guide 1.147, if any.

l 9904210331 990419 l PDR ADOCK 05000361 P PDR I

The use of penetrameiers are contained in paragraphs NB-5111 and NC-5111 to Section 111 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" of Section V.

2.2 Request for Relief J

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 appilicant 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 or unusual difficulty without a compensating increase in the level of quality and safety.

The licensee requested relief from the penetrameter requirements in paragraphs NB-5111 and NC-5111 to Section 111 of the 1992 Edition of the Code.

2.3 Basis for Relief The licensee believes that plaque type penetrameters are difficult to 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 a negative Al_ ARA impact due to the additional radiation exposure to the radiography crew.

The licensee believes that the use of wire type IQls are superior to plaque type 101 for nuclear I I

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 one-inch minimum length of the essential 101 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 tyoe 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 attemative 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 change, thus providing an acceptable level of quality and safety.

't. 5 3.0 EVALUATION 3.1 Proposed Alternative Examination The licensee proposed applying the sen.divity level specified in Tables NB-5111-1 and NC-5111-1 to Section 111 of the 1992 Edition of the Code to the selection of the ap, priate wire type IQls from Table 4 to Standard SE-747 of Article 22 to Section V of the 199e Edition of the Code.

3.2 Discussion in Volume 17 of the Ninth Edition of the Metals Handbook, published in 1989, it states that wire-type penetrameters are widel used in Europe, and a standard design is used in the United Kingdom, Germany, the Neth lands, and Scandinavia and by the International Organization for Standardization and the Inter, tknal Institute of Welding. The handbook goes on to state that wire penetrameters specified n . .M E 747-87 are widely used in the United States. ASTM developed this specification using a public forum with approval by public consensus.

The ASTM Standard E747-87 referenced in the Metals Handbook is identical to the 1989 Edition of ASME's Standard SE-747-87. To assist in determining equivalence between wire and plaque (hole) type IQls, these two standards provide an equation for calculating equivalency. In the 1989 Edition with 1991 Addenda of the Code, the equivalency equatiewas changed with the revised standard being identified as ASME Standard SE-747. The licensee proposed using the criteria from Table 4 to ASME Standard SE-747 for wire penetrameters as an alternate for the plaque penetrameters required by Tables NB-5111-1 and NC-5111-1 to Section lli of the 1992 Edition of the Code.

Wire penetrameters were not included in Section 111 of Code until the 1992 Edition with 1993 Addenda. Although the1992 Edition with 1993 Addenda of the Code has not been endorsed yet by NRC, this later Addenda to the Code includes requirements on the use of wire and plaque penetrameters. The staff's review compared the licensee's proposed attemative against Table NB-5111-1 (NC-5111-1) from the 1992 Edition with 1993 Addenda of the Code. The staff assembled a table similar to Table NB-5111-1 (NC-5111-1) to Section ill of the 1992 Edition with 1993 Addenda of the Code by merging like data from Table 4 to SE 747 to Section V of the 1992 Edition with Table NB-5111-1 (NC-5111-1) to Section lli of the 1992 Edition. The penetrameters from the newly created wire / plaque table compared against the penetrameters from Table NB-5111-1 (NC-5111-1) to Section lli of the 1992 Edition with 1993 Addenda of the Code showed that the newly created table lists wire diameters equal to or smaller (more conservative) than those in Table NB-5111-1 (NC-5111-1) to Section ill of the 1992 Edition with 1993 Addenda of the Code. The licensee's proposed use of wire penetrameter values from Table 4 to Standard SE-747 of Section V of the 1992 Edition of the Code provide values equal to or more conservative than the values agreed to through the consensus building process used by Section 111 of the Code.

1 J With the licensee applying the sensitivity level specified in Table NB-5111-1 (NC-5111-1) to Section lli of the 1992 Edition of the Code and the wire diameters for penetrameters from Table 4 to Standard SE-747 to Section V of the 1992 Edition of the Code, the staff believes that the results from radiographic examinations will be comparable between wire and plaque penetrameter, thus providing and acceptable level of quality and safety.

4.0 CONCLUSION

Based on the evaluation of the information provided, the staff concludes that the proposed alternative 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 Date: April 19, 1999 l

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