ULNRC-05990, Supplemental Information for 10 CFR 50.55a Request: Proposed Alternative to ASME Section XI Requirements for Leakage Testing of Reactor Pressure Vessel Head Flange Leakoff Lines (Relief Request I3R-14)

Supplemental Information for 10 CFR 50.55a Request: Proposed Alternative to ASME Section XI Requirements for Leakage Testing of Reactor Pressure Vessel Head Flange Leakoff Lines (Relief Request I3R-14)

ML13126A304
Person / Time
Site:	Callaway
Issue date:	05/06/2013
From:	Mclachlan M Ameren Missouri, Union Electric Co
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
ULNRC-05990
Download: ML13126A304 (10)

Text

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WAmeren Callaway Plant MISSOURI May 6, 2013 ULNRC-05990 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 10 CFR 50.55a Ladies and Gentlemen:

DOCKET NUMBER 50-483 CALLAWAY PLANT UNIT 1 UNION ELECTRIC CO.

FACILITY OPERATING LICENSE NPF-30 SUPPLEMENTAL INFORMATION FOR 10 CFR 50.55a REQUEST: PROPOSED ALTERNATIVE TO ASME SECTION XI REQUIREMENTS FOR LEAKAGE TESTING OF REACTOR PRESSURE VESSEL HEAD FLANGE LEAKOFF LINES (RELIEF REQUEST 13R-14)

Reference 1: Ameren Missouri Letter ULNRC-05986, "1 0 CFR 50.55a Request:

Proposed Alternative to ASME Section XI Requirements for Leakage Testing of Reactor Pressure Vessel Head Flange Leakoff Lines (Relief Request BR-14)," dated May 2, 2013 Pursuant to 10 CFR 50.55a(a)(3)(ii), and by letter dated May 2, 2013 (Reference 1), Ameren Missouri submitted Relief Request BR-14 in regard to the pressure at which leakage testing ofthe reactor pressure vessel head flange leakofflines must be perfonned, as specified per Paragraph IWC-5221 of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,Section XI.

The relief is requested on the basis that compliance with the Code-specified pressure requirement to test the leakofflines at system operating pressure is impractical and would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.

In the Relief Request submitted per the May 2, 2013 letter, Ameren Missouri provided justification for the requested relief, as well as a proposed alternative approach to the required leakage testing.

Drawings were also provided as an attachment to the letter. Ameren Missouri has determined, however, that additional information should be provided to facilitate the NRC's review of the Relief Request. The additional infonnation is hereby provided as Attachment 1 to this letter. In addition, the isometric drawing provided as one of the two drawings attached to the May 2, 2013 letter has been

......................................................................................................................... PO Box 620 Fulton, MO 65251 AmerenMissouri.com

ULNRC-05990 May 6, 2013 Page 2 revised to reflect an additional two to three feet of inaccessible piping. The revised drawing is provided as Attachment 2.

As noted in Ameren Missouri's May 2, 2013 letter, NRC verbal approval ofReliefRequest BR-14 is being sought dming the cunent refueling outage at Callaway. This supplemental letter is intended to supp01t prompt verbal approval upon receipt of the letter by the NRC.

No new regulatory commitments have been made or identified in this letter or its attachments. For any questions you may have regarding this request, please contact me at 573-544-8272 or Tom Elwood at 314-225-1905.

Mark A. McLachlan Director Engineering Services TBE/JAD/nls : Supplemental Information Regarding 10 CFR 50.55a Request BR-14 : Isometric Drawing (Revised)

ULNRC-05990 May 6, 2013 Page 3 cc: Mr. Arthur T. Howell Regional Administrator U.S. Nuclear Regulatory Commission Region IV 612 E. Lamar Blvd., Suite 400 Arlington, TX 76011-4125 Senior Resident Inspector Callaway Resident Office U.S. Nuclear Regulatory Commission 8201 NRC Road Steedman, MO 65077 Mr. Fred Lyon Project Manager, Callaway Plant Office ofNuclear Reactor Regulation U.S. Nuclear Regulatory Commission Mail Stop 0-8014 Washington, DC 20555-2738 Mr. James T. Polickoski Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Mail Stop 0-8B 1A Washington, DC 20555-2738

ULNRC-05990 May 6, 2013 Page4 Index and send hat*dcopy to QA File Al60.0761 Hardcopy:

Cetirec Corporation 4200 South Hulen, Suite 422 Fort Worth, TX 76109 (Certrec receives ALL attachments as long as they are non-safeguards and may be publicly disclosed.)

Electronic distribution for the following can be made via Other Situations ULNRC Distribution:

A. C. Heflin F. M. Diya C. 0. Reasoner III L. H. Graessle M. A. McLachlan S. A. Maglio L. H. Kanuckel G. S. Kremer NSRB Secretary R. Holmes-Bobo T. B. Elwood J. A. Doughty M.G. Hoehn STARS Regulatory Affairs Mr. John O'Neill (Pillsbury Winthrop Shaw Pittman LLP)

Missouri Public Service Commission

Attachment I to ULNRC-05990 Page I of4 Supplemental Information Regarding 10 CFR 50.55a Request 13R-14

Attachment I to ULNRC-05990 Page 2 of4 The following supplemental infonnation is provided in support of 10 CFR 50.55a Request 13 R-14 concerning leakage testing of the reactor pressure vessel head flange leakofflines as required per Paragraph IWC-5221 ofthe American Society of Mechanical Engineers (ASME) Boiler and Pressure Vesse! Code,Section XI.

Reference 1: Ameren Missouri Letter ULNRC-05986, "1 0 CFR 50.55a Request:

Proposed Alternative to ASME Section XI Requirements for Leakage Testing of Reactor Pressure Vessel Head Flange Leak off Lines (Relief Request BR-14)," dated May 2, 2013 Clarification of ASME Section XI Code Requirements:

Callaway is currently in its third Inservice Inspection Interval, which began December 19, 2004. At the time of this submittal, Refuel 19 is in progress, which is the first refuel of the third inspection period of the interval. The applicable Code is the American Society of Mechanical Engineers (ASME)

Section XI, 1998 Edition with 2000 Addenda. Relief is being requested from certain requirements of the pressure test directed by Table IWC-2500-1, Code Category C-H, Item Number C7.10.

Specifically, request is being sought from the requirements in IWC-5221, "Pressure."

Design Parameters of the Subject Piping and Components:

The system affected by this request consists of the ASME III Class 2 reactor pressure vessel (RPV) flange leak-offlines BB-075-BCB, BB-076-BCB, BB-077-BCB, and their associated valves. This system has design pressure and temperature ratings, and service pressure and temperature conditions (should the inner RPV 0-ring fail), of 650°F and 2485 psig, and 618°F and 2235 psig, respectively.

These are the same design and service conditions as the ASME III Class 1 loop piping.

Accessibility of the Subject piping for direct visual examination:

The total length of pipe from the inner monitor tube, line BB-076-BCB, to the point where the line tees with the outer monitor tube, line BB-075-BCB, is 71 feet. The total length of pipe from the outer monitor tube, line BB-075-BCB, to valve BBHV8032, which is the outermost limit of the system subject to the pressure test, is 79 feet. Included in the 79 feet of pipe run is tubing line BB-077-BCB and the line to drain valve BBV0081. Note that temperature element BBTE040 1, used to detect leakage from the reactor vessel 0-rings, is located 1 foot downstream ofBBHV8032.

Attachment I to ULNRC-05990 Page 3 of4 Lines BB-075-BCB and BB-076-BCB run parallel to each other and are each inaccessible for the first 32 feet due to being located in the annulus area between the reactor vessel and the primary shield wall.

The annulus area can only be accessed by way of the refueling cavity, which is tilled with water dming this test, and by way of the incore tunnel underneath the reactor vessel, which during refueling operations is prohibited fi:om being entered due to the high dose rates from the incore flux mapping thimbles being withdrawn from the reactor vessel.

Lines BB-075-BCB and BB-076-BCB exit the primary shield wall at an elevation of about 14 feet above the floor and travel horizontally along the wall for 22 feet until they drop down and exit the bioshield wall through a penetration that is about five feet off the floor. The line is uninsulated through this area and is visible, including inside the bioshield wall penetration, except for an approximately one foot section in a comer where direct sight is blocked by another line. The line outside of the bioshield, up to and including valve BBHV8032, is insulated and is about 5 feet off the floor.

Service History of the Subject Piping and Components:

Callaway's work history, as well as corrective action history was reviewed for service-related failures of the subject piping and component. The review identified no occurrences ofleakage or other failures on these components. This system does have 21 socket welds, 8 of which are inaccessible behind the primary shield wall, with the rest located outside of the bioshield wall.

Supplemental Information Regarding Performance of the Requested Alternate Pressure Test:

The mandated pressure for the system per IWC-5221 is that pressure developed while the system, or portion of the system, is in service performing its normal operating function or at the system pressure developed during a test conducted to verify system operability. For the subject piping, the pressure developed while the system is performing its normal operating function, i.e., directing leakage from failed RPV flange 0-rings to the reactor coolant drain tank (RCDT), would be RCS pressure (2235 psig).

During the proposed test, the pressure that this system will be subject to during the VT -2 examination will be due to the height of the water in the refueling cavity. The refueling cavity is filled to a minimum of 23 feet of water above the RPV flange for refueling activities. Therefore, the flange, located at plant elevation 2021 feet 7 inches, will see a pressure of at least 10 pounds per square inch.

As the piping travels down to the RCDT, the resultant static head pressure would increase. The lowest portion of the piping is at plant elevation 2005 feet 6 inches, and would experience a pressure of approximately 17 pounds per square inch.

To ensure the lines are clear of air prior to perfonnance of the VT-2 examination, the surveillance instructions have been revised to include a flush oflines BB-075-BCB and BB-076-BCB, after which

Attachment I to ULNRC-05990 Page 4 of4 a four-hour hold is required. Per the surveillance, the flush of the lines is accomplished by attaching a drain hose to the flange downstream ofvalve BBV0081, and then flushing lines BB-075-BCB and BB-076-BCB each for the greater of either 5 minutes or until no air is seen coming from the drain hose.

The pressure test with the VT-2 examination is expected to occur on May 7, 2013. With the refueling pool having been filled on April 13, 2013, the line will have been subject to water and pressure for 24 days.

to ULNRC-05990 Page 1 of2 Attachment 2 Isometric Drawing (Revised)