ML043210379
| ML043210379 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 11/23/2004 |
| From: | Ellen Brown NRC/NRR/DLPM/LPD2 |
| To: | Singer K Tennessee Valley Authority |
| Brown E, NRR/DLPM, 415-2315 | |
| References | |
| TAC MC3745, TAC MC3746 | |
| Download: ML043210379 (5) | |
Text
November 23, 2004 Mr. Karl W. Singer Chief Nuclear Officer and Executive Vice President Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801
SUBJECT:
BROWNS FERRY NUCLEAR PLANT, UNITS 2 AND 3 REQUEST FOR ADDITIONAL INFORMATION REGARDING ONE-TIME INTEGRATED LEAK RATE TESTING (TAC NOS. MC3745 AND MC3746)
Dear Mr. Singer:
By letter dated July 8, 2004, the Tennessee Valley Authority submitted an application to revise the Technical Specifications and the Licensing Basis for the Browns Ferry Nuclear Plant, Units 2 and 3 (TS change 448). The proposed amendment requests the modification of Technical Specification Section 5.5.12, Primary Containment Leakage Rate Testing Program to allow a one-time 5-year extension to the 10-year frequency of the performance-based leakage rate testing program for Type-A tests. The proposed changes are submitted on a risk-informed basis as described in Regulatory Guide 1.174, An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis.
The U.S. Nuclear Regulatory Commission staff has reviewed your submittal and finds that a response to the enclosed request for additional information is needed before we can complete the review. This request was discussed with Mr. Bert Morris of your staff on November 15, 2004, and it was agreed that a response would be provided within 30 days of the date of this letter. If you have any questions, please contact me at (301) 415-2315.
Sincerely,
/RA/
Eva A. Brown, Project Manager, Section 2 Project Directorate II Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket Nos. 50-260 and 50-296
Enclosure:
Request for Additional Information cc w/encl: See next page
ML043210379 NRR-088 OFFICE PDII-2/PM PDII-2/LA SPSB/SC PDII-2/SC NAME EBrown BClayton KManoly by memo dated MMarshall BMoroney for DATE 11/23/04 11/23/04 11/5/04 11/23/04
Mr. Karl W. Singer BROWNS FERRY NUCLEAR PLANT Tennessee Valley Authority cc:
Mr. Ashok S. Bhatnagar, Senior Vice President Nuclear Operations Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Michael J. Lorek, General Manager Nuclear Engineering Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Michael D. Skaggs Site Vice President Browns Ferry Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Decatur, AL 35609 General Counsel Tennessee Valley Authority ET 11A 400 West Summit Hill Drive Knoxville, TN 37902 Mr. John C. Fornicola, Manager Nuclear Assurance and Licensing Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. Kurt L. Krueger, Plant Manager Browns Ferry Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Decatur, AL 35609 Mr. Fredrick C. Mashburn Senior Program Manager Nuclear Licensing Tennessee Valley Authority 4X Blue Ridge 1101 Market Street Chattanooga, TN 37402-2801 Mr. Timothy E. Abney, Manager Licensing and Industry Affairs Browns Ferry Nuclear Plant Tennessee Valley Authority P.O. Box 2000 Decatur, AL 35609 Senior Resident Inspector U.S. Nuclear Regulatory Commission Browns Ferry Nuclear Plant 10833 Shaw Road Athens, AL 35611-6970 State Health Officer Alabama Dept. of Public Health RSA Tower - Administration Suite 1552 P.O. Box 303017 Montgomery, AL 36130-3017 Chairman Limestone County Commission 310 West Washington Street Athens, AL 35611
Enclosure REQUEST FOR ADDITIONAL INFORMATION ONE-TIME FREQUENCY EXTENSION FOR CONTAINMENT INTEGRATED LEAKAGE RATE TEST INTERVAL TENNESSEE VALLEY AUTHORITY BROWNS FERRY PLANT, UNITS 2 AND 3 DOCKET NOS. 50-260 AND 50-296 1.
Results of the previous Type-A tests for Browns Ferry Nuclear Plant (BFN), Units 2 and 3, are presented on a table shown in page E1-6 of the Tennessee Valley Authority (TVA) application for amendment, dated July 8, 2004. The table appears to indicate that the November 6, 1995, Type-A test for Unit 3 registered a leak rate almost three time the leak rates measured for the other three tests for both Units 2 and 3 reported in the table. Please discuss plausible reasons for registering such large fluctuations in the above mentioned BFN Type-A test results.
2.
Referring to the last paragraph of page E1-6 of the July 8 submittal, Appendix J Visual Inspections, discuss how the proposed one-time extension of the integrated leak rate test (ILRT) interval from 10 years to 15 years would impact the visual inspection plans originally scheduled for BFN containment. Specifically, provide a description of TVA's inservice inspection methods/plans for the additional 5-year extended period that would provide assurance that in the absence of an ILRT for 15 years, the containment structural and leak-tight integrity will be maintained.
3.
Regarding the Category E-A Examinations discussed on page E1-8 of the submittal, it is stated that the general visual examinations identified some mechanical damages such as pitting, gouges, dents, rust and arc strikes, which were said to be evaluated and found acceptable. Discuss the extent of the loss of the liner material that resulted from the observed mechanical damages and the technical basis for TVAs determination that the incurred damages were acceptable.
4.
With respect to the Category E-C Examinations discussed in the first paragraph of page E1-9 of the submittal, it is indicated that VT-1 visual examinations of the interior surfaces of Units 2 and 3 torus waterline region (elevation 536' to elevation 538') identified minor localized corrosion and pitting and these degradations were evaluated to be acceptable.
Discuss the extent of the loss of material that was associated with the localized corrosion and pitting observed and the technical basis for TVAs determination that the observed containment shell degradation was acceptable.
5.
Referring to the Category E-D Examinations (Seals, Gaskets, and Moisture Barriers) discussed on page E1-9 of the submittal, discuss past BFN operating experience regarding the results of the VT-3 visual examinations of seals, gaskets and moisture barriers implemented once each inspection interval. Also, describe the extent of defects found regarding BFNs moisture seal barrier and the defective portions replaced.
Considering the defects found in BFN containments moisture barriers, and its implication upon the affected liner degradation, discuss the potential negative impact of the proposed one-time ILRT interval extension upon TVAs continued ability to timely identify and dispose containment degradation and reasonably assure the leak-tightness and structural integrity of the BFN containment.
6.
With respect to the Generic Letter 87-05 Inspections discussed on page E1-10 of the submittal, TVA stated that no significant corrosion had occurred in the sand region but there has been evidence of water leaking from the sand bed drains, on both Units 2 and 3, since the 1987 inspections. Discuss the results of the ultrasonic testing thickness measurements at the sand bed region performed in September 1998 for Unit 3 and April 1999 for Unit 2, including the extent of liner thickness reductions observed and the basis for TVAs determination that the inspections verified the integrity of the liner. Also, considering the extent of the liner degradation found, discuss the potential negative impact of the proposed one-time ILRT interval extension upon TVAs continued ability to timely identify and dispose containment degradation and reasonably assure the leak-tightness and structural integrity of the BFN containment.
7.
Discuss BFNs past-operating experience regarding its use of the monitoring of the nitrogen makeup to containment as a complimentary means for assuring the leak tightness and structural integrity of the BFN containment. Discuss why the use of this supplementary approach strengthens TVAs case for requesting a one-time extension of the BFN containments ILRT interval.
8.
Inspections of some reinforced concrete and steel containment structures have identified degradation on the uninspectable (embedded) side of the drywell steel shell and steel liner of the primary containment. These degradations cannot be found by visual (i.e., VT-1 or VT-3) examinations unless they are through the thickness of the shell or liner, or when 100 percent of the uninspectable surfaces are periodically examined by ultrasonic testing. Provide additional information addressing how these undetected potential leakages under high pressure during core-damage accidents are factored into the risk assessment implemented for justifying the proposed one-time ILRT interval extension.