ML080670224

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Clarification of Staff Approval to Implement Mechanical Nozzle Seal Assemblies at Calvert Cliffs Nuclear Power Plant Unit Nos. 1 and 2 (TAC Nos. MB0557 and MB0558)
ML080670224
Person / Time
Site: Calvert Cliffs  Constellation icon.png
Issue date: 03/21/2008
From: Pickett D
NRC/NRR/ADRO/DORL/LPLI-1
To: Spina J
Calvert Cliffs
pickett , NRR/DORL, 415-1364
References
TAC MB0557, TAC MB0558
Download: ML080670224 (4)


Text

March 21, 2008 Mr. James A. Spina, Vice President Calvert Cliffs Nuclear Power Plant, Inc.

Calvert Cliffs Nuclear Power Plant 1650 Calvert Cliffs Parkway Lusby, MD 20657-4702

SUBJECT:

CLARIFICATION OF STAFF APPROVAL TO IMPLEMENT MECHANICAL NOZZLE SEAL ASSEMBLIES AT CALVERT CLIFFS NUCLEAR POWER PLANT, UNIT NOS. 1 AND 2 (TAC NOS. MB0557 AND MB0558)

Dear Mr. Spina:

By letter dated August 7, 2002 (Agencywide Documents Access Management System (ADAMS)

Accession No. ML011060236), and pursuant to Title 10 of the Code of Federal Regulations, Section 50.55a(a)(3)(i), the Nuclear Regulatory Commission (NRC) approved the use of mechanical nozzle seal assembly (MNSA) devices as an acceptable alternative to the requirements of Section XI of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code. Recent developments have demonstrated that clarification to the NRCs safety evaluation (SE) supporting this approval is desirable.

The NRC staffs SE did not include specific details regarding the intended applications of the MNSA devices. Rather, the SE simply concluded that the installation of MNSA devices was acceptable as a temporary alternative repair method for cracked Alloy 600 instrumentation and sampling nozzles in the Calvert Cliffs reactor coolant pressure boundary for up to two operating cycles. At the time of the submittal, the licensee did not have a specific need to install an MNSA device and was only requesting prior NRC approval in the event that a need would occur.

During the February 2008 refueling outage at Calvert Cliffs Unit 1, the licensee observed boric acid crystals emanating from a cracked Alloy 600 pressurizer heater sleeve penetration. The licensee decided to install an MNSA device on this line citing prior NRC approval in the above SE. Due to the lack of specificity in the staffs SE, questions were raised regarding the intended scope of applicability and whether MNSA devices should be limited to instrumentation and sampling nozzles as cited in the staffs SE.

The licensees submittal identified six MNSA designs intended for use at Calvert Cliffs. These six applications, which were identified in proprietary Enclosure 4 to the licensees letter dated November 17, 2000 (ADAMS Accession No. ML003770894, page 172 of 434), and in the non-proprietary Attachment 1 to the licensees letter dated March 14, 2001 (ADAMS Accession No. ML010780260), include:

  • Hot Leg Resistance Temperature Detector (RTD) Nozzle
  • Hot Leg Pressure Differential Transmitter or Sampling Nozzle
  • Pressurizer Heater Sleeve Nozzle
  • Upper Pressurizer Instrument Nozzle
  • Side Pressurizer RTD Nozzle
  • Bottom Pressurizer Instrument Nozzle

J. Spina Based upon internal discussions and a re-examination of our original SE, we concur with expanding the scope of the original SE, as intended by the licensees submittal, to include the six intended designs identified above. Our failure to address the specific applications in the SE was an oversight. There is no technical justification to exclude the use of the MNSAs on the pressurizer heater sleeves as opposed to limiting their use to instrumentation and sampling nozzles.

Please contact me at 301-415-1364 if you have any questions.

Sincerely,

/RA/

Douglas V. Pickett, Senior Project Manager Plant Licensing Branch I-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-317 and 50-318 cc: See next page

ML080670224 OFFICE LPL1-1/PM LPL1-1/LA CVIB/BC LPL1-1/BC NAME DPickett SLittle MMitchell MKowal 3/19/08 3/19/08 3/20/08 3/21/08 DATE Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2 cc:

Mr. Michael J. Wallace, President Ms. Kristen A. Burger, Esquire Constellation Energy Nuclear Group, LLC Maryland People's Counsel 750 East Pratt Street, 18th Floor 6 St. Paul Centre Baltimore, MD 21202 Suite 2102 Baltimore, MD 21202-1631 Mr. John M. Heffley, Senior Vice President and Chief Nuclear Officer Ms. Patricia T. Birnie, Esquire Constellation Energy Nuclear Generation Co-Director Group Maryland Safe Energy Coalition 111 Market Place P.O. Box 33111 Baltimore, MD 21202 Baltimore, MD 21218 President Mr. Roy Hickok Calvert County Board of NRC Technical Training Center Commissioners 5700 Brainerd Road 175 Main Street Chattanooga, TN 37411-4017 Prince Frederick, MD 20678 Mr. Louis S. Larragoite Mr. Carey Fleming, Esquire Manager - Nuclear Licensing Sr. Counsel - Nuclear Generation Constellation Energy Nuclear Generation Constellation Energy Nuclear Group, LLC Group 750 East Pratt Street, 17th floor 111 Market Place, 2nd Floor Baltimore, MD 21202 Baltimore, MD 21202 Mr. Jay S. Gaines Director, Licensing Calvert Cliffs Nuclear Power Plant 1650 Calvert Cliffs Parkway Lusby, MD 20657-4702 Resident Inspector U.S. Nuclear Regulatory Commission P.O. Box 287 St. Leonard, MD 20685 Mr. R. I. McLean, Manager Nuclear Programs Power Plant Research Program Maryland Department of Natural Resources 580 Taylor Avenue (B wing, 3rd floor)

Tawes State Office Building Annapolis, MD 21401 Regional Administrator, Region I U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406