ML13267A459

Request for Additional Information Regarding Relief Request RR-04-16

ML13267A459
Person / Time
Site:	Millstone
Issue date:	10/01/2013
From:	James Kim Plant Licensing Branch 1
To:	Heacock D Dominion Nuclear Connecticut
Kim J
References
RR-04-16, TAC MF2520
Download: ML13267A459 (4)

Text

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Mr. David A. Heacock President and Chief Nuclear Officer Dominion Nuclear Connecticut, Inc.

lnnsbrook Technical Center 5000 Dominion Boulevard Glen Allen, VA 23060-6711

SUBJECT:

MILLSTONE POWER STATION, UNIT 2- REQUEST FOR ADDITIONAL INFORMATION REGARDING RELIEF REQUEST RR-04-16 (TAC NO. MF2520)

Dear Mr. Heacock:

By letter dated August 1 2013, Dominion Nuclear Connecticut, Inc. (the licensee) submitted alternative request RR-04-16, requesting relief from the requirements of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (Code)Section XI, Paragraph IWA-4221. The 2004 Edition of ASME Code,Section XI, paragraph IWA-4221 requires the use of the construction code for repair and replacement activities at Millstone Power Station Unit 2.

The licensee is proposing to use phased array ultrasonic testing as an alternative to the required radiographic testing.

The U.S. Nuclear Regulatory Commission staff has reviewed the information provided by the licensee and has determined that the enclosed request for additional information (RAI) is needed in order to complete the review. The responses to RAI questions 2, 3.a, 3.c, 3.d, 3.e, 5, and 6 are requested to be provided by November 25, 2013. The responses to RAI questions 1, 3.b, and 4 are requested to be provided by February 28, 2014.

If you have any questions regarding this matter, please contact me at 301-415-4125.

Sincerely, James Kim, Project Manager Plant Licensing Branch 1-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-336

Enclosure:

Request for Additional Information cc w/encl: Distribution via Listserv

REQUEST FOR ADDITIONAL INFORMATION REGARDING MILLSTONE POWER STATION. UNIT 2 RELIEF REQUEST RR-04-16 DOCKET NO. 50-336 By letter dated August 1, 2013 (Agencywide Documents Access and Management System Accession No. ML13220A019), Dominion Nuclear Connecticut, Inc. (the licensee) submitted alternative request RR-04-16, requesting relief from the requirements of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (Code)Section XI, Paragraph IWA-4221. The U.S. Nuclear Regulatory Commission (NRC) staff requests that the licensee provide additional information to support the relief from ASME Code Section Xl-required radiographic testing of welds.

1. Please provide examples of successful detections and characterizations of fabrication flaws, including lack of fusion defects, lack of penetration defects, cracks, slag, and porosity in representative welds using a representative ultrasonic procedure. Include flaw maps showing the true state for examples of each type of flaw including those found by penetrant testing, the ultrasonic results including detection and characterization of flaws, and the radiographic results for these specimens.

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2. The hardship associated with the use of radiographic testing was described as an increased radiological dose to the people performing the inspections. What is the expected reduction in radiological dose that would result from the use of ultrasonic testing in lieu of radiographic testing for the welds covered in RR-04-16?

3. The technical basis for the reliable detection and characterization of fabrication flaws has thus far assumed that the inspections will be conducted from both sides of the weld. The few. experimental evaluations that have explored the reliability of the. single-sided ultrasonic testing (UT) suggest that detecting fabrication flaws,* especially lack of fusion defects, using single sided UT misses flaws found by inspections conducted from both sides (see EPRI Report 102-1181 page.A-5 and the paper "An Empirical Study on Ultrasonic Testing in Lieu of Radiography for Nuclear Power Plants" in the Proceedings of the 91h international conference on NDE in relation to structural integrity for nuclear and pressurized components). As the technical basis for the detection and characterization of flaws from one side of the weld has not been established, the following information on the single-sided examinations is required:

a. Which welds described in RR-04-16, based o"n the current designs, would require*

single-sided inspections and which welds would be inspected from both sides of the welds?

b. If single-sided ultrasonic inspections are to be used in lieu of radiographic testing for welds covered in RR-04-16, please provide a technical basis justifying the use of single-sided examinations for fabrication defects in the subject welds.

Enclosure

c. As the replacement piping has not been installed, and it is possible to design the system to allow access to both sides of the weld what would be the hardship or unusual difficulty and the expected increase in personnel radiation dose caused by designing the replacement Feedwater system to not require single-sided ultrasonic examinations for fabrication defects?

d. It is possible for some components to be fabricated outside of containment in a shop setting. What would be the hardship or unusual difficulty and expected increase in radiation dose to personnel from performing radiography on the welds that require single-sided ultrasonic examinations in a low-radiation environment?

e. What would be the hardship or unusual difficulty and expected increase in radiation dose to personnel that would be caused by performing radiography only on the welds that would require single-sided ultrasonic examinations?

4. The current technical basis for performing ultrasonic inspections in lieu of radiography assumes that the weld crowns will be removed and machined or ground flush. Will the weld crowns of the welds covered in RR-04-16 be machined or ground flush prior to the proposed ultrasonic inspections? If the weld crowns are not to be ground flush, please provide a technical basis, including a detailed description of the ultrasonic inspection procedure, showing that inspections with the weld crown present are able to reliably detect and characterize fabrication flaws.

5. The relief request defines the required examination zone as 100 percent of the weld volume and the weld-to-base metal interface on each side. Does this examination zone include ~ inch or ~ of the wall thickness or some other buffer area? Please provide a drawing of the examination area to be covered by the ultrasonic examinations. If a ~

inch or~ t buffer area around the weld is not to be used, please describe how the inspection procedure will conservatively include, in light of possible inner diameter and outer diameter repairs, the entire volume of the weld and fusion zone in the examination.

6. Radiographic testing provides an archival-quality record of the examination that can be stored and interpreted after several decades. Encoded electronic data requires backup and proprietary data formats may become obsolete in the future. How will the ultrasonic results be stored and protected from data loss and future changes in hardware and software that could render the data unreadable?

Mr. David A. Heacock October 1, 2013 President and Chief Nuclear Officer Dominion Nuclear Connecticut, Inc.

lnnsbrook Technical Center 5000 Dominion Boulevard Glen Allen, VA 23060-6711

SUBJECT:

MILLSlfONE PQWER STATION, UNIT 2- REQUEST FOR ADDITIONAL INFORMATION REGARDING RELIEF REQUEST RR-04-16 (TAC NO. MF2520)

Dear Mr. Heacock:

By letter dated August 1 2013, Dominion Nuclear Connecticut, Inc. (the licensee) submitted alternative request RR-04-16, requesting relief from the requirements of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (Code)Section XI, Paragraph IWA-4221. The 2004 Edition of ASME Code,Section XI, paragraph IWA-4221 requires the use of the construction code for repair and replacement activities at Millstone Power Station Unit 2.

The licensee is proposing to use phased array ultrasonic testing as an alternative to 'the required radiographic testing.

The U.S. Nuclear Regulatory Commission staff has reviewed the information provided by the licensee and has determined that the enclosed request for additional information (RAI) is needed in order to complete the review. The responses to RAI questions 2, 3.a, 3.c, 3.d, 3.e, 5, and 6 are requested to be provided by November 25, 2013. The responses to RAI questions 1,

• 3.b, and 4 are requested to be provided by February 28, 2014.

If you have any questions regarding this matter, please contact me at 301-415-4125.

Sincerely,

. /RAJ James Kim, Project Manager Plant Licensing Branch 1-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-336

Enclosure:

Request for Additional Information cc w/end: Distribution via Listserv Distribution:

PUBLIC RidsNrrPMMillstone Resource RidsNrrDeEpnb Resource LIPI-1 R/F RidsNrrLKGoldstein Resou~ce SCumblidge, NRR RidsNrrDoriDpr Resource RidsNrrDorllpl1-1 Resource RidsOgcRp Resource RidsNrrDeEicb Resource RidsRgn1 MaiiCenter Resource RidsAcrsAcnw_ MaiiCTR Resource ADAMS Accession No ..* Ml13267 A459 *See memo dated September 20 2013

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OFFICE LPL 1-1/PM LPL 1-1/LA DE/EPNB/BC LPL 1-1/BC (A)

NAME JKim* KG old stein . Tlllpold* RBeall DATE 10/01/13 09/30/13 9/20/13 10/01/13

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Off1c1al Record Copy