ML18036A769
| ML18036A769 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 07/13/1992 |
| From: | Williams J Office of Nuclear Reactor Regulation |
| To: | Medford M Tennessee Valley Authority |
| Shared Package | |
| ML18036A770 | List: |
| References | |
| TAC-M80618, TAC-M80619, TAC-M80620 NUDOCS 9207160304 | |
| Download: ML18036A769 (6) | |
Text
~
~gf\\ REQII P
Cy A
~~
00 p
Vlp
~O
>>>>*4 UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555 July 13, 1992 Docket Nos. 50-259, 50-260, and 50-296 Tennessee Valley Authority ATTN:
Dr. Hark 0. Hedford, Vice President Nuclear Assurance, Licensing 8 Fuels 3B Lookout Place 1101 Market Street Chattanooga, Tennessee 37402-2801
Dear Dr. Hedford:
SUBJECT:
SAFETY EVALUATION AND REQUEST FOR ADDITIONAL INFORMATION REGARDING BROWNS FERRY NUCLEAR PLANT UNITS 1, 2, AND 3 DESIGN CRITERIA FOR LOWER DRYWELL STEEL PLATFORMS AND MISCELLANEOUS STEEL (TAC NOS.
- M80618, H80619, AND M80620)
To support restart of the Browns Ferry Nuclear Plant (BFN) Unit 2, the NRC staff had reviewed and accepted interim operability criteria for lower drywell steel platforms and miscellaneous steel.
As a result of this review, the staff defined two post-restart action items in this area.
First, the staff required the Tennessee Valley Authority (TVA) to address the adequacy of applying the 1978 edition of the American Institute of Steel Construction (AISC) specification for steel design since the original BFN FSAR criteria were based on the 1963 version.
- Second, TVA was required to provide the long-term steel design criteria for staff review to determine if they conform with the FSAR requirements.
In response to these post-restart
- items, TVA submitted the long-term design criteria for lower drywell steel platforms and miscellaneous steel at BFN Units 1, 2, and 3 by letter dated June 12, 1991.
This letter noted that the long-term criteria were different from those used to support BFN Unit 2
- restart, and sought NRC acceptance of the long-term criteria.
A letter dated November 8, 1991 provided a reference to the BFN document containing the criteria.
Following meetings and telephone conferences with TVA, the staff requested additional information in a letter dated December 12, 1991.
The TVA response to this request was dated February 6, 1992.
The staff requested, among other things, that TVA address the application of ductility ratios in the stee'1 design criteria.
After reviewing TVA's response, the staff provided its position rejecting the generic use of ductility ratios in a letter dated March 19, 1992.
The enclosed safety evaluation (SE) documents the staff review of the steel design criteria.
In general, the staff finds the criteria to be acceptable.
However, there are several open items identified by the staff which TVA must address.
These items are:
9207160304.
920713 PDR ADOCK'5000259 P
~
4f IIII"m~ C<ha cry
<<.04<J(,
)
t'>> '
e' 4>>
~
g
1.
As noted in the enclosed SE Section 2.2, the staff does not agree that TVA has demonstrated compliance with the FSAR requirements for steel design.
First, application of a ductility ratio is not permitted by the FSAR.
- Second, the shear stress limit of 0.52 F
proposed in the criteria submitted on June 12, 1991 is greater t5an the FSAR limit of 0.4 F
TVA has not provided a justification for this increased limit.
tVA should justify the increased shear stress limit, as noted in SE Section 2.5.3.
TVA has stated that the FSAR will be revised to reflect changes in the steel design criteria.
This revision and the associated justification will be reviewed by the staff when it becomes available.
2.
In the enclosed SE Section 2.4, TVA is requested to clarify the criteria to state that the absolute sum of dynamic forces will be used vs. evaluation of dynamic force phase relationships.
The staff feels this request is consistent with previous TVA commitments.
3.
SE Section 2.5. 1 requires TVA to clarify the FSAR with regard to circumstances where the upper stress limit should be applied.
4.
SE Section 2.5.2 states the staff does not accept 0.9 of the critical buckling stress, since this limit provides insufficient margin.
TVA is requested to submit a lower limit for staff review which demonstrates acceptable margin.
TVA is requested to provide information justifying the increased shear stress limit and a revised critical buckling stress limit as soon as practical.
The staff will prepare a supplemental safety evaluation addressing these items.
Please contact me at (301)504-1470 if you have any questions.
This requirement affects 9 or fewer respondents and, therefore, is not subject to Office of Hanagement and Budget review under P.L.96-511.
Sincerely, Original signed by Joseph F. Williams, Project Hanager Project Directorate II-4 Division of Reactor Projects I/II Office of Nuclear Reactor Regulation
Enclosure:
Safety Evaluation cc w/enclosure:
See next a
e OFC NAHE PDII-4 LA HSanders PDII-4 PH PDII-4 PH JWilliam.as TRoss 7A'DII-4 FHeblPon DATE-7 /3 9z 7 0 92 7x3 92 713 92
Jf t j.
Tennessee Valley Authority ATTN:
Dr. Hark 0. Hedford Browns Ferry Nuclear Plant CC:
Mr. John B. Waters, Director Tennessee Valley Authority ET 12A 400 West Summit Hill Drive Knoxville, Tennessee 37902 Hr. J.
R.
Bynum, Vice President Nuclear Operations 3B Lookout Place 1101 Market Street Chattanooga, Tennessee 37402-2801 Hr.
R.
R. Baron, Site Licensing Manager Browns Ferry Nuclear Plant Tennessee Valley Authority P.O.
Box 2000
- Decatur, Alabama 35602 Hr. 0. J. Zeringue, Vice President Browns Ferry Nuclear Plant Tennessee Valley Authority P.O.
Box 2000
- Decatur, Alabama 35602 Hr. H. J. Burzynski, Manager Nuclear Licensing and Regulatory Affairs 5B Lookout Place Chattanooga, Tennessee 37402-2801 TVA Representative Tennessee Valley Authority 11921 Rockville Pike Suite 402 Rockville, Maryland 20852 General Counsel Tennessee Valley Authority ET llH 400 West Summit Hill Drive Knoxville, Tennessee 37902
- Chairman, Limestone County Commission P.O.
Box 188
- Athens, Alabama 35611 Claude Earl Fox, H.D.
State Health Officer State Dept. of Public Health State Office Building Montgomery, Alabama 36130 Regional Administrator U.S.N.R.C.
Region II 101 Marietta Street, N.W.
Suite 2900 Atlanta, Georgia 30323 Hr. Charles Patterson Senior Resident Inspector Browns Ferry Nuclear Plant U.S.N.R.C.
Route 12, Box 637
- Athens, Alabama 35611