ML20197A963

Forwards Rev 0 to Relief Request NR-Note 5,addressing Limited Ultrasonic Exams of Four Class 1 Welds in Safety Injection Sys,Per NRC Request.Request Will Be Incorporated Into Preservice Insp Program.Related Info Encl

ML20197A963
Person / Time
Site:	Byron
Issue date:	10/16/1986
From:	Ainger K COMMONWEALTH EDISON CO.
To:	Harold Denton Office of Nuclear Reactor Regulation
References
2272K, NUDOCS 8610270430
Download: ML20197A963 (8)

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/ ) Commonwealth One First Nabonal PlazaEdison Chica00, Illinois l.

(N/ Chicago, Illinois 60690 0767 7~.

/ Address Reply tz Post Office Box 767 October 16, 1986 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555

Subject:

Byron Station Unit 2 Preservice Inspection NRC Docket No. 50-455 Reference (a): July 23, 1986 letter from K. A. Ainger to H. R. Denton

Dear Mr. Denton:

Reference (a) provided the Byron Unit 2 Preservice Inspection Program notes and relief requests to the NRC. Note 5 of the program addressed limited ultrasonic examinations of four Class I welds in the safety injection system. During the preservice inspection of these welds, 100% of the ASME Code required examination volume was scanned circumferenti-ally. However, a small percentage (6.29 to 8.29%) of the volume could not be axially scanned due to interference from ganuna plugs or branch connections. Since more than 90.5% of the examination volume was examined axially, Commonwealth Edison did not seek relief from ASME Section XI requirements for these welds. However, the NRC staff has requested Commonwealth Edison to submit a relief request for these weld examinations since essentially 100% of the weld examination volume was not scanned.

Attached is relief request NR-Note 5 which addresses the weld examinations discussed above. This relief request will be incorporated into the Byron Unit 2 Preservice Inspection Program. Note 5 of the program will be deleted.

Please direct any questions regarding this matter to this office.

One signed original and fifteen copies of this letter and attachment are provided for NRC review.

Very truly yours, 8610270430 861016 .

PDR ADOCK 05000455

• G PDR K. A. Ainger Nuclear Licensing Administrator 1m Attachment h

cc: Byron Resident Inspector i\

2272K

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NR-NOTE 5

. R v. 0 RELIEF REQUEST NR-NOTE 5

1. SYSTEM: Safety Injection

2. NUMBER OF ITEMS: 4

3. ASME CODE CLASS: 1

4. PERTINENT CODE REQUIREMENTS: Table IWB-2500-1, Examination Category B-J, Item B9.11 requires a surface and volumetric examination of the volume described in figure IWB-2500-8. The volumetric examination performed during the inspection interval shall cover all the area of 25% of the circumferential joints. The examination includes at least a pipe diameter length, but not more than 12 inches of each longitudinal weld intersecting the circumferential welds required to be examined.

IWB-2200 states, " Examinations required by this article shall be completed prior to initial plant startup. In addition, these preservice examinations shall be extended to include essentially 100% of the pressure retaining welds in Class 1 components, except in those components exempted from examination by IWB-1220."

Mandatory Appendix III, Article III-4000 requires examination for:

a. Reflectors parallel to the weld seam.

The angle beam examination for reflectors parallel to the weld seam shall be performed by a full V path from one side or a one-half V path from two sides of the weld, where practicable.

b. Reflectors transverse to the weld seam.

The angle beam examination for reflectors transverse to the weld seam shall be performed on the weld crown on a single scan path to examine the weld root by one-half V path in two directions along the weld.

5. BASIS FOR RELIEF: The circumferential welds listed below were examined 100% by volumetric techniques. 100% of the required weld volume was examined by a complete circumferential scan. However, a small percentage of each weld (in no case greater than 8.29%) was not examinable by an axial half-v-path or full-y-path scan (see Attachments 1 thru 4).

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(0946M/0095M)

7 NR-NOTE 5 Riv. 0 Line Weld Blocked By  % Missed Attachment 2SIO9BA-10" J18 Gamma Plug 6.29* 1 2SIO9BA-10" J27 Gamma Plug 6.29* 2 2SIO9BD-10" J1 Branch Connection 8.29* 3 2SIO9BD-10" J25 Gamma Plug 6.66* 4 Note: *In all cases above, the percentage missed is a conservative estimate as shown on Attachment 5 to this relief request.

The procedure for axially scanning these welds requires that the transducer be twisted back and forth while scanning. As a result, more volume is actually examined than that reflected by the above numbeers.

6. ALTERNATE TEST METHOD: In all cases above, a surface examination (liquid penetrant) and a visual examination (leak test) was performed. Also, the welds were inspected volumetrically by the radiographic method to meet the ASME Section III requirements. The Section III radiographs could be used to meet the preservice examination requirements, however, it is not our intent to use radiography for inservice inspections.

7. JUSTIFICATION: Per ASME Section III, radiography and hydrostatic testing have been completed on these welds. Per ASME Section XI the welds were ultrasonically scanned for transverse reflections. Only a small percentage of the axial ultrasonic scan was not performed. The combination of these weld examinations provide a level of structural integrity adequate to support plant operation.

(0946M/0095M) l

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GAMMA PLUG OR BRANCH CONNCCTION SCALEsNONE ATTACHMENT 5 NR-NOTE 5

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