ML19325C410
| ML19325C410 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 10/06/1989 |
| From: | Michael Ray TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML19325C411 | List: |
| References | |
| NUDOCS 8910160192 | |
| Download: ML19325C410 (4) | |
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TENNESSEE VALLEY AUTHORITY:
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3 U.S.~ Nuclear Regulatory Commission
^ ATTN:: Document Control Desk-j
- Hashington, D.C.
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i Gentlemen:
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- In the Matter of-
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Docket No. 50-260
'l Tennessee. Valley Authority =
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t' BRONNS' FERRY NUCLEAR' PLANT-(BFN) - UNIT 2 - RESPONSE TO NRC INSPECTION REPORT' s
NO.'50-260/89-31
Reference:
NRC Inspection Report-No. 50-260/89-31, dated July 17, 1989.
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'This lettertis in response to the open 1tems of_NRC Inspection Report No 50-260/89-31 dated-July 317, 1989. The design areas reviewed during this inspection were the seismic analysis of-the reactor building including the
' reactor pressure vessel (RPV), RPV support, internals, and the. evaluation of the primary components of the nuclear steam supply system.
.Three open items were summarized in the conclusion of this inspection report.
1.
The: methods used by GE for primary system evaluation are acceptable provided that' additional information is provided to justify the adequacy
- of method Numbers 2 and 3.
T.VA agreed to supply this information when available..
- In response to this item, GE performed a reevaluation of the Browns Ferry reactor vessel and internals, utilizing the correct RPV dynamic model and addressing the conditions stipulated for qualification Methods 1, 2, or 3.
1The results of:this reevaluation are documented in the GE seismic assessment L
' report included as Enclosure 1 to this submittal.
12.: Due to. deletion of Appendix J from the current BFN FSAR, the staff was not
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able to. review the original design basis and criteria for the primary
- systems'. TVA' agreed to redocket Appendix J and to find out the cause of deleting this appendix if possible.
LIn' response'to this item, TVA redocketed the original design basis for the tBrowns Ferry Units 1, 2, and 3 RPV analyses via a submittal dated June 23,
~1989 As noted in that submittal, during the general update of the FSAR in 1
1984, simplification of the detailed design content was intended.
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.Accordingly, the body of these appendices was deleted and replaced with short L'
' summaries, t
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When the: dynamic model of. the RPV, internals, and_ supports was developed, TVA incorrectly assumed the existence of seismic restraints at the lower-
.4 end of the CR0 housings.- This inspection finding was confirmed by the 1
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_ original design drawing and a field walkdown. TVA.is developing a 4
. modification for'the installation of seismic restraints on the CRD, housings and will report to the staff when finalized. This open issue'is
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considered as an Unresolved Item (URI 89-31-01).
i As a' result ofIthis finding it is unclear to the staff when'the error might have first occurred and on which RPV model-the design basis and results documented in the BFN FSAR are based.
In order to clarify these uncertainties, the staff requested that TVA provide:- (1) the original
.selsmic analysis results (reportt) used to license BFN, (2) the revision date of the' current FSAR and the version of RPV model documented in the L
current FSAR, (3) the' revision of the current Table C.0-5 of the FSAR and model used to generate the stresses tabulated in this table. (4) a copy of GE Report 22A2016, Revision 0, 1, and 2, and (5) a copy of Appendix J originally found in earlier versions of the FSAR.
l TVA has committed to install seismic restraints on the CRD housings prior to
. unit restart.
The current reevaluation performed by GE~for the RPV and H
intervals-assumes the prerestart installation of these = support structures, o-Responses to the five~information requests follow:
A.
Origina1Lseismic analysis used to license BFN The original seismic analysis used to license BFN is Appendix J, RO. 'The backup calculations for Appendix J cannot be found.
This is why the current model was developed.
B.
Establish revision date of current FSAR and version of RPV model documented in the current FSAR The revision date of the current FSAR is July 22, 1988, Amendment 6.
The version of the RPV model referenced in the current FSAR is still Appendix J RO. Appendix J was deleted from the current FSAR, but the seismic responses from the Appendix J model for the RPV, shield wall, and pedestal were incorporated into Chapter 12 (Figures 12.2-34, -35. -36,
~ 37, -38
-39).
Also Section 3.3.5.5 discusses the seismic model and Figure 3.3-11 shows a schematic of the RPV mathematical model which is representative of the model from Appendix J.
C.
Revision date of current FSAR Table C.0-5 and model used to generate the stresses tabulated in this table
'The model used to generate the stresses tabulated in Table C.0-5 for the CRD housing is based on GE Report 22A2016 R2. The revision date of the
. table is July 22, 1988, Amendment 6.
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F D.~.' Copy of GE-Report 22A2016, R2
' A copy of the report was made available to NRC during tb August audit, e
Due to its proprietary classification, issuance was not available.
E.
Copy of Appendix J found:in earlier FSAR The original Appendix J RPV evaluation was redocketed with-the staff as discussed in previous item No. 2.
Very truly yours, TENNESSEE VALLEY AUTHORITY r~'
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Madage Nuclear Licensing and Regulatory Affairs Enclosures-
.cc (Enclosures):
Ms. S. C. Black, Assistant Director
-for Projects TVA Projects Division U.S. Nuclear Regulatory Commission
-One White Flint, North
'11555 Rockville Pike Rockville, Maryland '20852 i
s Mr. B. A. Wilson, Assistant Director for Inspection Programs
_ TVA Projects Division U.S. Nuclear Regulatory Commission Region II 101~Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 NRC Resident Inspector Browns Ferry Nuclear Plant Route 12, Box 637
' Athens, Alabama '35609-2000 l
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General Electric Co.
Seismic Assessment of Browns Ferry 2 Reactor Vessel and Internals
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