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Response to Request for Additional Information Regarding Third Ten-Year Inservice Inspection (Isl) Interval Relief Request ISI-3-30, Inspection of Reactor Vessel Head In-Core Instrument Nozzles
	ML093570270
Person / Time
Site:	San Onofre
Issue date:	12/18/2009
From:	St-Onge R; Southern California Edison Co
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
References
	Download: ML093570270 (16)
	v • d • e

Richard I. St. Onge JSOUTHERN EDISON CALIFORNIA An EDISON INTERNATIONAL Company Director Nuclear Regulatory Affairs December 18, 2009 10CFR50.55a U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001

Subject:

Docket Nos. 50-361 and 50-362 Response to Request for Additional Information Regarding Third Ten-Year Inservice Inspection (ISl) Interval Relief Request ISI-3-30, Inspection of Reactor Vessel Head In-Core Instrument Nozzles San Onofre Nuclear Generating Station, Units 2 and 3

Reference:

Letter from R. St Onge (SCE) to Document Control Desk (NRC), dated October 2, 1999;

Subject:

Docket Nos. 50-361 and 50-362, Third Ten-Year Inservice Inspection (ISI) Interval Relief Request ISI-3-30, Inspection of Reactor Vessel Head In-Core Instrument Nozzles San Onofre Nuclear Generating Station, Units 2 and 3 (ADAMS Accession #ML092790155)

Dear Sir or Madam,

By the referenced letter Southern California Edison (SCE) submitted Inservice Inspection (ISI) Relief Request ISI-3-30, regarding inspection of Reactor Vessel Head In-Core Instrument Penetration Nozzles.

By e-mail dated December 2, 2009, the NRC requested additional information regarding SONGS relief request ISI-3-30. Enclosed is SCE's response to the NRC request for additional information.

This letter and the enclosure contain no new commitments.

P.O. Box 128 San Clemente, CA 92674

Document Control Desk December 18, 2009 Should you have any questions, please contact Ms. Linda T. Conklin at (949) 368-9443.

Sincerely,

Enclosure:

cc: E. E. Collins, Regional Administrator, NRC Region IV R. Hall, NRC Project Manager, San Onofre Units 2 and 3 G. G. Warnick, NRC Senior Resident Inspector, San Onofre Units 2 and 3

ENCLOSURE Response to NRC Request for Additional Information Regarding Relief Request ISI-3-30

NRC Questions regarding ISI-3-30 and SCE Responses to NRC questions NRC Question 1:

Please describe the spatial extent, i.e., the distance above the root of the J-groove weld and the distance below the toe of the J-groove weld, of the eddy current (ECT) examination and the ultrasonic (UT) time of flight diffraction (TOFD) examination.

SCE Response:

Eddy current examinations of the inner diameter surface and lower end surface were performed on all ten In Core Instrument (ICI) penetrations. The inner diameter examination included the entire surface from at least 1.5 inches above the uppermost point of the J-weld root downward to the bottom edge of the ID surface where it intersects with the lower end. The entire lower end surface was also examined using eddy current examination. The outer diameter ICI penetration surface from the J-weld toe downward to the lower end was not examined.

There are no ultrasonic Time of Flight Diffraction (TOFD) examination techniques that meet 50,55(a) qualification requirements. However, each of the SONGS Unit-2 ICI penetrations were examined during the current refueling outage using TOFD techniques that are similar to those qualified for Control Element Drive Mechanism (CEDM) penetrations and to those used previously under NRC First Revised Order EA-03-009.

All TOFD examination volumes extended upward to at least 1.5 inches above the uppermost point of the ICI J-weld root. The lower extent of TOFD volumetric coverage below the J-weld toe varied due to as-built weld lengths and loss of Ultrasonic Test (UT) coupling due to weld induced distortion of the lower penetration extremity. Measured TOFD coverage below the J-weld toe is provided in the tables in Attachment 1 of this Enclosure. These tables provide measurements at 30-degree increments around each of the ten ICIs (penetration numbers 92 through 101).

NRC Question 2:

Please provide a best estimate of the fractional volume of the in-core instrument nozzle (ICI) nozzle material which could be successfully evaluated from the nozzle ID using UT TOFD examination for each ICI nozzle. This evaluation should be restricted to the volume of the nozzle from the root of the J-groove weld to 2 inches below the root or the end of the nozzle, whichever is less.

SCE Response:

The tables in Attachment 1 of this Enclosure provide measurements of the evaluated TOED examination coverage below the J-groove weld. The estimated fraction of incore instrument nozzle volume from the root of the J-weld to 2 inches below the root of the J-weld that was evaluated using TOFD is provided below. These estimates were calculated by assuming that the measurement represents the average coverage within the 30 degree tube section, and that each section represents one twelfth of the entire volume of interest.

ICI 92 93 94 95 96 97 98 99 100 101 Penetration Fractional 0.94 1.00 0.98 0.98 0.99 0.99 0.99 1.00 1.00 0.96 volume NRC Question 3:

Please provide information on spatial extent (length, height) of compensatory manually delivered ECT examination performed on the nozzle outside diameter as the result of unacceptable quality UIT TOFD data.

SCE Response:

The quality of UT TOMD data was acceptable to at least 1-inch below the J-weld root over the full circumference of all ICI penetrations. This met the criteria proposed for relief from performing manually delivered ECT examinations of the nozzle outside diameter. Therefore no compensatory outside diameter surface examinations were performed.

Enclosure 1 Attachment 1 Measured Time of Flight Diffraction Coverage Below the J-weld Toe San Onofre Unit 2 In-Core Instrument Penetration Nozzles

1304322 1

n WESpynrE IHT 9 AN AT1 ICI PENETRATION #92 C16 DATA SCE UNIT 2 2009 TUBE MEASUREMENTS Azimuth 00 300 600 900 1200 1500 1800 2100 2400 2700 3000 3300 J-Weld Root 3.24" 3.76" 5.24" 7.32" 9.08" 10.48" 11.04" 10.72" 9.8" 7.68" 5.76" 4.16" J-Weld Toe (Lower) N/A"* 2.0" 2.8" 4.84' 8.16" 9.16" 9.4" 8.7" 7.48" 5.12" 3.16" 2.68" Lower Exam Extent 2.2" 1.84" 2.6" 4.12" 5.52" 8.2" 7.48" 7.04" 5.72" 4.16" 2.78" 2.4" Coverage below 1.04" 1.92" 2.64" 3.2" 3.56" 2.28" 3.56" 3.68" 4.08" 3.52" 2.98" 1.76" Root Name: Phil Lancaster Date: 11/24/09 PDQS# 1015 Note: Values shown above are relative indicated instrument positions.