ML20198K374

Safety Evaluation Authorizing Second 10-yr ISI Interval for Plant,Units 1 & 2 Relief Request from ASME Boiler & Pressure Vessel Code Requirements to Use Performance Demonstration Initiative Program

ML20198K374
Person / Time
Site:	Calvert Cliffs
Issue date:	01/05/1998
From:	NRC (Affiliation Not Assigned)
To:
Shared Package
ML20198J647	List: ML20198J641 ML20198K374
References
NUDOCS 9801140396
Download: ML20198K374 (4)

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UNITED 8TATES s* , NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 3000HeH

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SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION ON THE SECOND TEN-YEAR INSERVICE INSPECTION INTFJDlg

, CALVERT CLIFFS NUCLEAR POWER PLANT. UNIT NOS.1 & 2 l RELIEF REQUEST FROM THE AMERICAN SOCIETY OF i MECHANICAL ENGINEERS BOlLER AND PRESSURE VESSEL CODE (ASME CODE)

REQUIREMENTS TO USE PERFORMANCE DEMONSTRATION INITIATIVE PROGRAM DOCKET NOS, 50 317 & $0 318

1.0 INTRODUCTION

The Technical Specifications for Calvert Cliffs Nuclear Power Plant (CCNPP) Units 1 & 2, state that the inservice inspection and testing of the ASME Code Class 1,2, and 3 components shall be performed !n accordance with Section XI of the ASME 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)(i).10 CFR 50.55a(s)(3) states that altematives to the requirements of paragraph (g) may be used, when authorized by the NRC, if (i) the proposed attematives would provide an acceptable level of quality and safety, or (ii) compliance with the specified requirements would result in hardship or unusual difficulty 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 Componerits," to the extent practical within the limitations of design, geometry, and materials of construction of the components, The regulations require that inservice examination of components and system pressure tests conducted during the first ten year interval and subsequent intervals 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 interval, subject to the limitations and modifications listed therein. The applicable edition of Section XI of the ASME Code for Calvert Cliffs Units 1 & 2, for the second inservice inspection (ISI)intervalis the 1983 Edition through the Summer 1983 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 and subject to Commission approval.

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Pureuant to 10 CFR 50.55a(g)(5), if the licensee determines that conformance with an I examination requirement of Section XI of the ASME Code is not practical for its facility,  !

information shall be submitted to the Commission in support of that determination and a request j made for relief from the ASME Code requirement. After evaluation of the determination, '

pursuant to 10 CFR 50.55a(g)(6)(i), the Commission may grant relief and may impose altomative l 4

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 i to the burden upon the licensee that could result if the requirements were imposed.

By letter dated October 14,' 19g7, Saltimore Gas and Electric Company (BGE or the licensee)  !

requested to use the Performance Demonstration initiative (PDl) Program based on the criteria of  !

. Appendix Vill,Section XI of the ASME Code,1992 Edition, including the 19g3 Addenda as an j aNemative to the requirement of the 1983 Edition of ASME Code,Section XI, through the  :

Summer 1983 Adc'enda, for ultrasonic examination of reactor vessel welds in both units of 1 1 Calvert Cliffs.  !

, The NRC staff has reviewed and evaluated the licensee's request and supporting information on  !

the proposed altomative to the Code requirements for Calvert Cliffs Units 1 and 2, pursuant to l the provisions of 10 CFR 50.55a(s)(3)(1).

2.0 DISCUSSION  :

I d Component identification l Reactor Pressure Vessel Units 1 and 2 I i  :

L o The PDI technique will be used to ultrasonically examine the following welds.

l Circumferential Wolds -

Wold Nos. 8 203,9 203, and 10 203 - I Longitudinal Wolds Wold Nos.1203A/B/C,2 203A/B/C, and 3 203A/B/C Lower Head Welds Weld Nos. 4 204 and 1204A

, o A combination of PDI and the ASME Code techniques will be used to examirw the following welds, i Reactor Vessel to Flange Weld ,

Wold No.- 7 203  ;

Nozzle to Shell Welds -  ;

. Weld Nos.10-205A/B and 4 205A/B/C/D_  !

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Code Reauirement ASME Section XI,1983 Edition through the Summer 1983 Addenda, Table IWB-25001, ,

Examination Category B-A, items D1.11, B1.12, B1.22, B1.30, and B D, item B3.90 require l volumetric examination. The requirements for volumetric examinations are stated in Article '

IWA 2232, which requires that examinations be conducted in accordance with Article 4 of ASME Code,Section V, as amended by ASME Code,Section XI.

Licensee's Proposed Attemative Examination procedurer, equipmeni, and personnel qualified by performance demonstration will be utilized in accordance with the PDI Program, in combination with ASME Code,Section V, Article 4 techniques. Attachment (1) provides a comparison of the proposed PDI technique for CCNPP and the standard Article 4,Section V and Regulatory Guide 1.150 (RG) procedures.

As a minimum, all Code requirements of iho 1983 Edition through Summer 1983 Addenda of Section XI will be implemented, except where specific differences have been identified in this submittal and Reference (a), in addition, as mentioned above, it is our intention to satisly the 10 CFR 50.55a(g)(6)(ii)(A)" Augmented," RPV inspection requirements.

Ucensee's Supportino Informetion BGE has contracted with Southwest Research Institute (SwRI) to perform the Second Ten Year RPV examination using a combination of the PDI qualified techniques and ASME Gection V Article 4 techniques. SwRI's procedures were qualified in accordance with the PDI program covering Supplements 4, " Qualification Requirements for the Clad / Base Metal Interface of Reactor Vessel," and 6, " Qualification Requirements for Reactor Vessel Welds Other than Clad / Base MetalInterface," of Appandix Vill,Section XI, ASME Code. Both double and single-sided approaches were qualified for Supplement 4 applications and for Supplement 6 applications up through 12 inch well thicknesses. (SwRl's PDI certification is on file at the Electric Power Research Institute Non Destructive Examination Center in Charlotte, NC.)

SwRI's PDI detection precedure utilizes two types of search units (55-60grees, multibeam) when scanning cea be accomplished from two sides of the weld, and three types of search units (45,55, and multibeam) when scanning can be accomplished from one side of the weld. The multibeam s6 arch unit is used to examine the inner 25 percent thickness. The 45 and 55 degree shear wava search units are used to examine the outer 75 percent. A 0-degree search unit may also be used to detect laminar reflectort, and deterwns component thickness. (NOTE:

Baltimore Gas and Electric Company has instructed SwRl to scan from two sides of each weld whenever it is possible.) Scanning is performed: (1) perpendicular to the weld for flaws oriented parallel to the weld; and (2) parallel to the weld for flaws oriented perpendicular (transverse) to the weld. Flaw oiserimination methods are independent of signal amplitude. Scenning sensitivities are determined based on the actual material noise.

Analysis and sizing of indications are performed by qualified Level ill Data Analysts using SwRI procedures. Regardless whether the detection examinations are being performed per ASME Code or PDI procedures, SwRI's sizing procedures utilize tip diffraction methods qualified in accordance with the PDI guidelines.

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3.0 EVALUATION 8 The PDi program based on the crHeria of Appendix Vill,Section XI of the ASME Code,1992 ,

EdNion,1993 Addenda, requires that ultrasonic equipment, procedures, and examiners be tested on flawed and notched motorit.ls and configurations similar to those found in actual plant condN6ons. Honos, performance based ultrasonic examination techniques provide a higher  !

degree of rel6abilNy for detection and characterization of flew when compared to the conventional amphtudo-based ultresonic techniques required by the current Code. The staff has assessed the PDI program activities and has approved the use of PDI techniques at other sites.

Based on the information provided by SOE, the staff has evaluated the PDI program proposed ,

for_ ultrasonic examination of reactor pressure vessel wolds in Calvert Cliffs Units 1 and 2 during >

the second ten year inspection interva!. The staff compared the licensee's proposed examination

- technique based on the PDI with that of the current Code and the RG 1.150 and determined that ,

the PDI technique would provide better sensitivity to flaw detection than that of the cunently  ;

applicable standards. Furthermore, the sizing and evaluation of flaw is more accurate using  !

multibeam tip-diffraction technique under the licensee's proposed PDI program than the amplitude based flew sizing allowed by the current Code. BGE has noted under " Supporting -;

- Information," that its detection procedures provide, where feasible, for the scanning of the  ;

examination volume from both sides of the weld on the same surface. The staff requires two i side scannings when it is feasible, however, when configuration or adjacent parts of the component are such that scanning from both sides is not feasible, this fact shall be included in  !

the report of examination. The staff has determined that the proposed altemative to implement  ;

the PDl program for the reactor vessel examination would provide an equivalent or a better  !

examination than that of the current standards. ,

4.0 CONCLUEN i

ihe staff has reviewed and evaluated the licebsee's proposed attemative to implement the PDI I program for the reactor vessel examination in both units of Calvert Cliffs during the second ten-year inspection interva!. A compar; son of the ultrasonic testing technique used in the PDI with '

that of the current Code and the RG 1.150, indicates that the PDI technique provides an

. equivalent or a better examination of the reactor vessel than that of the goveming standards.

Hence, the staff has determined that the proposed attemative would provide an acceptable level ,

of quality and safety.

Therefore, the proposed attemative is authorized, pursuant to 10 CFR 50.55a(a)(3)(i) for the reactor vessel examination during the second ten year interval of Calvert Cliffs Units 1 and 2.

Principal Contributor: P. Patnaik 4 t

Date: January 5, 1998- '

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