ML14073A600

Response to Request for Clarifying Lnformation Regarding American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&Pv) Section Xl Code of Record for Second 10-Year Lnservice Lnterval 2001 Edition

ML14073A600
Person / Time
Site:	Watts Bar
Issue date:	03/13/2014
From:	Church C Tennessee Valley Authority
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML14073A600 (5)

Text

Tennessee Valley Authority, Post Office Box 2000, Spring City, Tennessee 37381-2000 March 13, 2014 10 CFR 50.55a ATTN. Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C . 20555-0001 Watts Bar Nuclear Plant, Unit 1 Facility Operating License No. NPF-90 NRC Docket No. 50-390

Subject:

Response to Request for Clarifying lnformation Regarding American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Section Xl Code of Record for Second 1O-Year lnservice lnterva!

2001 Edition

References:

1. Letter from TVA to NRC, "American Society of Mechanical Engineers (ASME)

Boiler and Pressure Vessel (B&PV) Section Xl Code of Record for Second 10 Year lnservice lnterval 2001 Edition," dated January 10, 2014 2 Electronic Mail from NRC to TVA, "Watts Bar Nuclear Station, Unit 1 -

Request for Additional lnformation Related Request for Alternative Number ISPT-O2, Regarding System Leakage Test of Reactor Pressure Vessel Head Flange Seal Leak-Off Piping," dated February 11,2014 Letter from TVA to NRC, "Response to Request for Additional lnformation Regarding American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Section Xl Code of Record for Second 10-Year lnservice lnterval 2001 Edition," dated February 21,2014 By letter dated January 10,2014 (Reference 1), the Tennessee Valley Authority (TVA) submitted a request for alternative regarding system leakage test of reactor pressure vessel head flange seal leak-off piping. By Electronic Mail from NRC to TVA dated February 11,2014 (Reference 2), TVA received a Request for Additional lnformation (RAl) regarding the proposed request for alternative. TVA provided its response to the Reference 2 RAI in the Reference 3 letter on February 21,2014. ln a teleconference on February 26,2014, the NRC requested additional clarification regarding the proposed alternative visual inspection provided in Reference 1 and additional details regarding the configuration of the reactor vessel flange provided in Reference 3.

U.S. Nuclear Regulatory Commission Page 2 March 13,2014 The enclosure to this letter provides the requested clarifying information.

Please address any questions regarding this request to Gordon Arent at (423) 365-2004.

Site Vice President Watts Bar Nuclear Plant

Enclosure:

Response to NRC Request for Clarifying lnformation cc (Enclosure):

NRC RegionalAdministrator - Region ll NRC Resident lnspector - Watts Bar Nuclear Plant Director, Division of Radiological Health - Tennessee State Department of Environment and Conservation

ENCLOSURE TEN NESSEE VALLEY AUTHORITY WATTS BAR NUCLEAR PLANT UNIT {

Response to NRC Request for Clarifying lnformation Additional lnsoection Details:

The lnservice lnspection Program Augmented Examinations of the Reactor Vessel Hot Leg (HL) nozzle safe ends are performed with qualified personnelfrom the TVA lnspection Services Organization (lSO). These examinations are an enhanced visualexam (VE) that requires a W-2 qualified individual. To reduce the dose associated with this examination and the proposed VT-2 examination of the Reactor Vessel Seal Leakoff Monitoring lines, TVA shall perform both examinations simultaneously utilizing the same personnelfor both tasks while making a single entry inside the Biological Shield (Bioshield) Wallto employ ALARA considerations in reducing dose to station personnel.

ln order to comply with the requirements of ASME Code Case N-805, these examinations will be scheduled for performance during the core off-load period with the Reactor Cavity flooded to the normal refueling level. This level will provide the static head as described in the response to RAI Question 5 on the WBN Relief Request submittal (Reference 3 from the cover letter). Both the Reactor HL nozzle safe end and Reactor Vessel Flange Leakoff Line examinations will be performed to detect evidence of past leakage (boric acid residue, staining, or any other indications of past leakage)

Additional Confiouration Details:

The inner and outer O-ring monitoring tube taps in the reactor vesselflange are located at elevation 723'-6 5/8'. As shown on Attachment 1, the approximate location of the inner O-ring monitoring tube is on the 253 degree azimuth and the approximate location of the outer O-ring monitoring tube is on the 286 degree azimuth. As shown on Attachment 2, the inner O-ring monitoring tube is located radially between the inner O-ring and outer O-ring. The outer O-ring monitoring tube is located radially outboard of the outer O-ring. The tubing for each monitoring tube travels radially around the outside of the vessel to a sleeve in the Bioshield wall at the 338 degree azimuth, then travels approximately 10 feet through the Bioshield wall. The inner and outer monitoring tubing travel through lower containment to a sleeve in the crane wall at the 296 degree azimuth. The inner and outer tubing connect to a common header to the Reactor Coolant Drain Tank downstream of their respective manual isolation valves. : Reactor Vessel Flange : Flange Detail

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