ML030030863
| ML030030863 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 01/03/2003 |
| From: | Anand R NRC/NRR/DLPM/LPD2 |
| To: | Scalice J Tennessee Valley Authority |
| Brown Eva, NRR/DLPM, 415-2315 | |
| References | |
| TAC MB4579 | |
| Download: ML030030863 (5) | |
Text
January 3, 2003 Mr. J. A. Scalice Chief Nuclear Officer and Executive Vice President Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, Tennessee 37402-2801
SUBJECT:
SEQUOYAH NUCLEAR PLANT UNIT 2 REQUEST FOR ADDITIONAL INFORMATION CONCERNING LICENSEE IDENTIFIED MATERIAL WASTAGE (TAC NO. MB4579)
Dear Mr. Scalice:
During a forced outage that began on December 26, 2002, the Tennessee Valley Authority (TVA, the licensee) identified leakage from a compression fitting on the Reactor Vessel Level Indication System. Additional licensee inspection revealed indications of material wastage on the reactor pressure vessel head. The U.S. Nuclear Regulatory Commission (NRC) staff held a conference call with the licensee on January 3, 2003, to discuss the extent of the material wastage and the licensees evaluation of the structural integrity wastage area.
As discussed during the conference call on January 3, 2003, the NRC staff requires responses to the enclosed Request for Additional Information to proceed with its review. During the call, Mr. Pedro Salas, the Sequoyah Licensing Manager, stated that TVA would respond to this request within 30 days of the date of this letter. Mr. Salas also indicated that the pictures, drawings, and related evaluation forwarded in draft form to the NRC staff would be submitted with their response.
Please have your staff contact Eva Brown at (301) 415-2315, if there are any questions regarding the enclosed request.
Sincerely,
/RA by E.Brown acting for/
Raj K. Anand, Project Manager, Section 2 Project Directorate II Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No. 50-328
Enclosure:
Request for Additional Information cc w/enclosure: See next page
- See previous concurrence OFFICE PDII-2\\PM PDII-2\\LA PDIII-2\\PM
- EMCB\\BC PDII-2\\SC NAME EBrown BClayton SBloom TChan for WBateman KJabbour for AHowe DATE 01/03/03 01/03/03 1/3/03 01/03/03 01/03/03
REQUEST FOR ADDITIONAL INFORMATION REACTOR PRESSURE VESSEL HEAD MATERIAL WASTAGE SEQUOYAH NUCLEAR PLANT, UNIT 2 DOCKET NO. 50-328
- 1. There are apparently two leak sources: (1) through a reactor vessel level indication system (RVLIS) mechanical joint and (2) through a conoseal or canopy seal control rod drive mechanism penetration. What was the impact of these two separate leakage sources (i.e.,
what was the extent of the degradation)? How long have there been leaks from these two sources and how was that determined?
- 2. It was communicated that degradation on the upper head is somewhat groove-like, about 5-inches long, and 1/8-inch deep. This morphology is not typical for wastage caused by boric acid; please provide more details to describe the morphology of the degradation. Is the extent of the degradation consistent with TVAs expectations with respect to head temperatures, exposure time, etc.?
- 3. What is the trend of reactor coolant system (RCS) unidentified leakage since the last refueling outage and how well does the amount of boron recovered correlate to the known trend of RCS unidentified leakage? What is the location of insulation seams in the vicinity of this degradation? What is the distance between the leaking RVLIS mechanical joint and the top of the reactor vessel head? What is the approximate temperature of this joint? What is the general equipment configuration in the area of this joint with respect to ventilation in the area and the leak path for the leaking RCS fluid given ventilation in the area?
- 4. Explain why the Westinghouse fatigue evaluation focuses on one additional startup and shutdown cycle.
- 5. How was the extent of the degradation evaluated? For example, it looks like some borated water could have contacted the RV flange bolts. How was this assessed if the bolts were not removed for inspection?
- 6. What caused Tennessee Valley Authority to inspect the RV head? Was there a licensing commitment, TS requirement, or some other vehicle that caused them to inspect? What was the amount of unidentified leakage at the time of shutdown? When was the last time TVA inspected the head and what did the inspection consist of (e.g., bare metal visual)? What would have been the consequences had the inspections not been performed, the borated water leakage identified, corrected, and cleaned up?
- 7. What was the root cause for leakage occuring in the RVLIS mechanical fitting and how will you confirm that there will not be any additional leaks of this nature?
Mr. J. A. Scalice SEQUOYAH NUCLEAR PLANT Tennessee Valley Authority cc:
Mr. Karl W. Singer, Senior Vice President Nuclear Operations Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. James E. Maddox, Acting Vice President Engineering & Technical Services Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Richard T. Purcell Site Vice President Sequoyah Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Soddy Daisy, TN 37379 General Counsel Tennessee Valley Authority ET 11A 400 West Summit Hill Drive Knoxville, TN 37902 Mr. Robert J. Adney, General Manager Nuclear Assurance Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Mark J. Burzynski, Manager Nuclear Licensing Tennessee Valley Authority 4X Blue Ridge 1101 Market Street Chattanooga, TN 37402-2801 Mr. Pedro Salas, Manager Licensing and Industry Affairs Sequoyah Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Soddy Daisy, TN 37379 Mr. D. L. Koehl, Plant Manager Sequoyah Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Soddy Daisy, TN 37379 Senior Resident Inspector Sequoyah Nuclear Plant U.S. Nuclear Regulatory Commission 2600 Igou Ferry Road Soddy Daisy, TN 37379 Mr. Lawrence E. Nanney, Director Division of Radiological Health Dept. of Environment & Conservation Third Floor, L and C Annex 401 Church Street Nashville, TN 37243-1532 County Executive Hamilton County Courthouse Chattanooga, TN 37402-2801 Ms. Ann P. Harris 341 Swing Loop Road Rockwood, Tennessee 37854