ULNRC-06012, Response to Request for Additional Information Regarding Relief Request 13R-14, Proposed Alternative to ASME Code, Section XI Requirements for Leakage Testing of Reactor Pressure Vessel Head Flange Leakoff Lines

Response to Request for Additional Information Regarding Relief Request 13R-14, Proposed Alternative to ASME Code,Section XI Requirements for Leakage Testing of Reactor Pressure Vessel Head Flange Leakoff Lines

ML13186A050
Person / Time
Site:	Callaway
Issue date:	07/03/2013
From:	Maglio S Ameren Missouri
To:	Document Control Desk, Office of Nuclear Material Safety and Safeguards
References
TAC MF1745, ULNRC-06012
Download: ML13186A050 (7)

Text

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WAmeren Callaway Plant MISSOURI July 3, 2013 ULNRC-060 12 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 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION REGARDING RELIEF REQUEST 13R-14, PROPOSED ALTERNATIVE TO ASME CODE, SECTION XI REQUIREMENTS FOR LEAKAGE TESTING OF REACTOR PRESSURE VESSEL HEAD FLANGE LEAKOFF LINES (TAC NO. MF1745)

References:

1) ULNRC-05986 dated May 2, 2013 (ADAMS Accession No. ML13123A095)

2) ULNRC-05990 dated May 6, 2013 (ADAMS Accession No. ML13126A304)

3) NRC Letter "Request for Additional Information Re: 13R-14, Proposed Alternative to ASME Code,Section XI Requirements for Leakage Testing of Reactor Pressure Vessel Head Flange LeakoffLines (TAC No. MF1745)," dated May 17, 2013 (ADAMS Accession No. ML13136A059)

Pursuant to 10 CFR 50.55a(a)(3)(ii), and by letter dated May 2, 2013 (Reference 1), as supplemented by letter dated May 6, 2013 (Reference 2), Union Electric Company (Ameren Missouri) proposed an alternative to Section XI, paragraph IWC-5221 of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (Code) for visual examination of reactor pressure vessel head flange leakofflines (Relief Request I3R-14). As compliance would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety, in lieu of the requirement to pressurize the subject leakoff lines to normal operating pressure prior to performing a VT -2 visual examination, Ameren Missouri proposed to use the pressure developed when the refueling cavity is filled to the normal refueling water level.

PO Box 620 Fulton, MO 65251 AmerenMissouri.com

ULNRC-060 12 July 3, 2013 Page 2 The NRC staff provided verbal authorization on May 6, 2013 for the proposed alternative described in Relief Request 13R-14 for the remainder of the third 10-year inservice inspection interval. By letter dated May 17, 2013 (Reference 3), the NRC staff transmitted a request for additional information (RAI) needed to complete its formal review.

Ameren Missouri's response to the RAI is provided in the attachment to this letter.

This letter and its attachment do not contain new commitments. None of the material presented herein is considered proprietary by Ameren Missouri.

Please contact me at 573-676-8719 or Jim Kovar at 314-225-1478 for any questions you may have regarding this response.

Sincerely, f) .A, V\\ ~

S.A.M~

Regulatory Affairs Manager JPK/nls

Attachment:

Response to Request For Additional Information (RAI) Regarding Relief Request 13R-14

ULNRC-060 12 July 3, 2013 Page 3 cc: Mr. Arthur T. Howell Regional Administrator U.S. Nuclear Regulatory Commission Region IV 1600 East Lamar Boulevard Arlington, TX 76011-4511 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 of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Mail Stop 0-8B 1 Washington, DC 20555-2738

ULNRC-060 12 July 3, 2013 Page4 Index and send hardcopy to QA File A160.0761 Hardcopy:

Certrec Corporation 4150 International Plaza Suite 820 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 Responses and Reports ULNRC Distribution:

A. C. Heflin F. M. Diya C. 0. Reasoner III L. H. Graessle S. A. Maglio T. B. Elwood Corporate Communications NSRB Secretary STARS Regulatory Affairs Mr. John O'Neill (Pillsbury Winthrop Shaw Pittman LLP)

Attachment to ULNRC-06012 Page 1 of3 RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION (RAI) REGARDING RELIEF REQUEST I3R-14

Attachment to ULNRC-06012 Page 2 of3 Question #1 Please describe any incidents of significant reactor pressure vessel flange 0-ring leakage at Callaway Plant.

Callaway Response Callaway has no history of reactor pressure vessel flange 0-ring leakage.

Question #2 When there is leakage past the inner 0-ring and the valve on the inner 0-ring leakage line is closed, the line between the flange and the closed valve may be pressurized to the reactor operating pressure, 2235 pounds per square inch gauge.

a. Please describe any plans for performing a VT-2 visual examination on the inner 0-ring line while it is pressurized to reactor operating pressure.

Callaway Response So long as leakage is within plant Technical Specification limits and there is no indication of leakage past the outer 0-ring, the plant is not required to shut down upon indication of leakage. The valves isolating the leak off lines are located outside the bioshield and can be accessed and operated while the plant is at power.

Control Room annunciator response procedure OTA-RK-00020 Addendum 58D, "RV Flange Leakoff Temperature High," directs the isolation of the inner 0-ring leakage line upon indication of leakage. This procedure is being revised to have Operations perform a visual examination for leakage of the accessible portions of the line 10 minutes after line isolation.

Additionally, an on-demand surveillance is being generated to perform a VT-2 examination on the accessible portion of the line after a minimum hold time of 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.

Accessible portions of the line include 2 feet of insulated line outside of the bioshield and 22 feet of uninsulated line that can be observed from the bioshield entrance.

b. Please provide the length of the line that can be visually inspected.

Callaway Response 24 feet of the pressurized line is accessible for visual inspection.

c. Please describe how much of the inspected length is insulated.

Callaway Response 2 feet of the pressurized line is insulated.

d. Please provide the hold time after the line is pressurized before a VT-2 visual examination is performed.

Attachment to ULNRC-06012 Page 3 of3 Callaway Response OTA-RK-00020 is being revised to require a visual inspection of the accessible line no less than 10 minutes after the inner 0-ring leak off line is isolated and pressurized.

The on-demand surveillance for this line will require a four-hour hold time.

e. Please describe any hardship associated with performing the examination (i.e., temperature, radiological dose, etc.).

Callaway Response Examining additional piping would involve entrance to the bioshield where elevated dose rates would be encountered.

f. What would be the expected radiation field in the area being inspected during the time that the pressurized line could be examined? Please clarify the time needed to perform the VT-2 visual examination.

Callaway Response The pressurized portion of piping outside the bioshield is in a radiation field of approximately 5 mRemlhr. Of the pressurized piping inside the bioshield, 22 feet can be seen from the bioshield entrance with the examiner standing in a radiation field of 100 to 500 mRemlhr. To examine the remaining piping inside the bioshield, personnel would have to enter a radiation field of greater than 16 Remlhr and would have to maneuver in a congested area coming in close proximity to the cross-over loop piping.

The time needed to perform the VT-2 on the accessible portions of line would be less than five minutes. The time needed to examine the additional piping inside the bioshield would also be less than five minutes but would put the examiner in very close proximity to the cross-over loop piping.