ML091910365

Nuclear Regulatory Commission Staff Review of the 2008 Steam Generator Tube Inspections

ML091910365
Person / Time
Site:	Millstone
Issue date:	07/21/2009
From:	Sanders C Plant Licensing Branch 1
To:	Heacock D Dominion Nuclear Connecticut
Sandeers, Carleen, NRR/DORL, 415-1603
References
TAC ME0094, FOIA/PA-2011-0115
Download: ML091910365 (3)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 July 21, 2009 Mr. David A. Heacock President and Chief Nuclear Officer Dominion Nuclear Connecticut, Inc.

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

SUBJECT:

MILLSTONE POWER STATION, UNIT NO.2 - NUCLEAR REGULATORY COMMISSION (NRC) STAFF REVIEW OF THE 2008 STEAM GENERATOR TUBE INSPECTIONS (TAC NO. ME0094)

Dear Mr. Heacock:

By letters dated October 24, 2008, and May 20, 2009 (Agencywide Document Access and Management System Accession Nos. ML083090396 and ML091540203, respectively),

Dominion Nuclear Connecticut, Inc., (DNC or the licensee) submitted information pertaining to the 2008 steam generator tube inspections performed at Millstone Power Station, Unit 2 (MPS2) during the cycle 18 refueling outage.

The NRC staff has reviewed the information DNC provided and concludes that DNC has provided the information required by the MPS2 Technical Specifications and that no additional follow-up is required at this time. The NRC staff's review is enclosed. This closes TAC No. ME0094.

If you have any questions, please contact me at 301-415-1603.

Sit;, ,~L Carleen J. San , Project Manager Plant Licensing nch 1-2 Division of Opera Ing Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-336

Enclosure:

As stated cc w/encl: Distribution via Listserv

REVIEW OF 2008 STEAM GENERATOR TUBE INSPECTIONS MILLSTONE POWER STATION, UNIT NO.2 DOCKET NO. 50-336 By letters dated October 24, 2008, and May 20, 2009 (Agencywide Document Access and Management System Accession Nos. ML083090396 and ML091540203, respectively),

Dominion Nuclear Connecticut, Inc., (DNC or the licensee) submitted information pertaining to the 2008 steam generator (SG) tube inspections performed at Millstone Power Station, Unit NO.2 (MPS2) during the cycle 18 refueling outage.

MPS2, has two SGs, each one contains approximately 8,523 thermally treated Alloy 690 tubes.

Each tube has a nominal outside diameter of 0.75 inches and a nominal wall thickness of 0.0445 inches. The tubes were hydraulically expanded at both ends for the full depth of the tubesheet. The tubes are supported by type 410 stainless steel lattice grids.

DNC provided the scope, extent, methods, and results of their SG tube inspections in the October 24, 2008, and May 20, 2009, letters. In addition, the licensee described corrective actions (e.g., tube plugging) taken in response to the inspection findings.

Based on its review of DNC's submittals, the U.S. Nuclear Regulatory Commission (NRC) staff has the following observations and comments:

• As of the 2008 refueling outage, the SGs had operated for approximately 117 effective full-power months (EFPM). The SGs have operated for approximately 101 EFPM in their 144 EFPM sequential period.

• There are no tubes in close proximity to each other.

• There is one tube in SG 1 that was only partially expanded into the tubesheet. The tube is not expanded for approximately 10 inches near the top of the tubesheet.

Based on a review of the information provided, the NRC staff concludes that DNC provided the information required by the MPS2 Technical Specifications. In addition, the NRC staff concludes that there are no technical issues that warrant follow-up action at this time since the inspections appear to be consistent with the objective of detecting potential tube degradation and the inspection results appear to be consistent with industry operating experience at similarly designed and operated units.

Enclosure

JUly 21,2009 Mr. David A. Heacock President and Chief Nuclear Officer Dominion Nuclear Connecticut, Inc.

Innsbrook Technical Center 5000 Dominion Boulevard Glen Allen, VA 23060-6711 SUB"IECT: MILLSTONE POWER STATION, UNIT NO.2 - NUCLEAR REGULATORY COMMISSION (NRC) STAFF REVIEW OF THE 2008 STEAM GENERATOR TUBE INSPECTIONS (TAC NO. ME0094)

Dear Mr. Heacock:

By letters dated October 24, 2008, and May 20, 2009 (Agencywide Document Access and Management System Accession Nos. ML083090396 and ML091540203, respectively),

Dominion Nuclear Connecticut, Inc., (DNC or the licensee) submitted information pertaining to the 2008 steam generator tube inspections performed at Millstone Power Station, Unit 2 (MPS2) during the cycle 18 refueling outage.

The NRC staff has reviewed the information DNC provided and concludes that DNC has provided the information required by the MPS2 Technical Specifications and that no additional follow-up is required at this time. The NRC staff's review is enclosed. This closes TAC No. ME0094.

If you have any questions, please contact me at 301-415-1603.

Sincerely, Ira!

Carleen J. Sanders, Project Manager Plant Licensing Branch 1-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-336

Enclosure:

As stated cc w/encl: Distribution via Listserv DISTRIBUTION:

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DATE 7/20109 7/5109 06124/2009* 7121109 Official Record Copy