ML18033A818
| ML18033A818 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 06/30/1989 |
| From: | Michael Ray TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| TAC-00305, TAC-305, NUDOCS 8907100257 | |
| Download: ML18033A818 (11) | |
Text
gCCEMRATED DISTRIBUTION 'KMONSTRXTlON SYSTEM REGULA1 Y INFORMATION DISTRIBUTZO
'YSTEM (RIDS)
't ACCESSlON NBR:8907100257 DOC.DATE: 89/06/30 NOTARIZED: NO DOCKET FACIL:50-,260 Browns Ferry Nuclear Power Station, Unit 2, Tennessee 05000260 AUTH.NAME AUTHOR AFFILIATION RAY,M.J.
Tennessee Valley Authority RECIP.NAME
'ECIPIENT AFFILIATION Document Control Branch (Document Control Desk)
SUBJECT:
Forwards clarification 6 update to program for qualifying seismic qualification of small bore piping.
DISTRIBUTION CODE:
D030D COPIES RECEIVED:LTR M-ENCL 3 SIZE:
5 TITLE: TVA Facilities Routine Correspondence NOTES:1 Copy each to: S.Black,D.M.Crutchfield,B.D.Liaw, R.Pierson,B.Wilson 05000260 5
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TENNESSEE VALLEYAUTHORITY CHATTANOOGA. TENNESSff 37401 5N 157B Lookout Place U.S. Nuclear Regulatory Commission ATTN:
Document Control Desk Washington, D.C.
20555 Gentlemen:
Docket No. 50-260 In the Matter of
)
Tennessee Valley Authority
)
BROWNS FERRY NUCLEAR PLANT (BFN) "- UNIT 2 SEISMIC QUALIFICATION OF SMALL BORE PIPING (NRC TAC NO. 00305)
This letter describes the program for the Seismic Qualification of Browns Ferry Unit 2 Small Bore Piping.
It supplements our previous submittal of.
April 29, 1988, providing further clarification of the pre and post unit 2 restart program scope.
If any questions exist, please telephone Patrick P. Carier, Manager of Site Licensing, at (205) 729-3570.
Very truly yours, TENNESSEE VALLEY AUTHORITY As a brief background, a Nonconformance Report (NCR) and a Significant Condition Report (SCR) were written to address deficiencies in the criteria for routing and installing small bore piping.
NCR BFNMEB 8406.was.. written to address the application of the criteria to the install'ati'on. of sched'ule 160 small bore piping.
SCR BFNCEB 8520 was written to address deficiencies in the support details included in the criteria.
The enclosed report (enclosure
- 1) describes our program regarding the Seismic Qualification of Small Bore Piping.
Enclosure 2 contains a list of commitments.
Enclosures cc:
See page 2
- Manager, Nuc ea Licensing and Regulatory Affairs bsO ag071000Cg 050 p
SgO OOOO F90 p
An Equal Opportunity Employer
v
U.S.. Nuclear Regulatory Commission cc (Enclosures):
Ms.
S.
C. Black, Assistant Director for Projects TVA Projects Division U.ST Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852 Mr. B. A. Wilson, As s i s tant 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
P
ENCLOSURE 1
TENNESSEE VALLEY AUTHORITY BRONNS FERRY NUCLEAR PLANT UNIT 2 SMALL BORE PIPING AND SUPPORTS JUNE 1989 This report is to clarify and update TVA's program for qualifying seismic Class I small bore piping at Browns Ferry Nuclear Plant (BFN) and supersedes TVA's submittal to the NRC on the small bore program, dated April 29, 1988.
The scope of the program presented in this report was discussed in the TVA/NRC meeting on November 17, 1988.
ISSUE Significant condition reports have questioned the adequacy of base plates, concrete
These questions revolve around the criteria used to design and install those supports.
BACKGROUND The majority of the Class I small bore (one-half to two-inch diameter) piping at BFN was field routed and field supported.
Installation was in accordance with American National Standards Institute standards.
Two criteria were issued for BFN small bore piping design.
The first design criteria was "Design Criteria for Supporting Process Instrument Air Lines," dated May 3, 1971.
The other was "Criteria for Seismically Qualifying Field Run Piping Sizes 1/2 through 2 in.," which was issued on November 29',
1972.
Both criteria were reissued as controlled document BFN-50-712 in 1980.
In 1984, a nonconformance report (NCR BFNMEB 8406) was written on the application of BFN-50-712 to the installation of schedule 160 pipe since the schedule 160 pipe was not addressed in this design criteria.
Nhile revising BFN-50-712 to address schedule 160 pipe, it was determined that the
.qualification of some base plates in the typical support details of the criteria could not be verified and that no weld details had been specified.,
It was also determined that some support members for field routed schedule 160 piping could be under-designed since their selection was based on the tables in the design cri teria for schedule 40 and 80 piping.
A significant condition report (SCR BFNCEB 8520) was written addressing those conditions and BFN-50-712 was revised to place the support details on hold pending the resolution of the SCR.
RESOLUTION In order to address the above concerns regarding the seismic qualification of Class I small bore piping, detailed analysis in accordance with design criteria was performed on 30 representative piping problems and for 130 associated supports.
The results of the analyses were evaluated to identify attributes which cause qualification concerns wi th the piping and supports.
The remaining piping and support installations within the scope of this program are being evaluated against these attributes through an engineering walkdown.
For the piping and supports where these attributes are found to exist, further evaluations are performed to ensure the ability of the piping or supports to meet criteria requirements.
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The small bore piping program is being completed in two phases as discussed below.
Phase 1 is required prior to Unit 2 Cycle 5 restart.
Phase 2 will be performed post-restart.
Phase 1 (Pre-Restart)
The scope for Phase 1 of this program is the seismic class I Unit 2 and common small bore piping and supports within the Design Baseline Program Safe Shutdown Restart Boundary which includes an approximate total of 27,000 ft. of piping and 4,000 supports.
Those items within this boundary which do not meet the interim operability criteria (BFN-50-C-7303) are modified to meet the long term design criteria (BFN-50-C-7103 and BFN-50-C-7107) prior to restart.
Those items which do not meet the long term design criteria but are within the interim operability criteria will be modified post restart (Phase 2).
In February
- 1989, changes to the seismic long term design criteria and new seismic Amplified Response Spectra (ARS) required an evaluation of all work completed to date on this program.
Additional modifications resulting from this re-evaluation will be implemented in accordance with the above requirements.
No additional attributes were identified due to the new ARS/seismic criteria re-evaluation of the original 30 analyses.
Small byre piping excluded from this program previously because engineering calculations existed are also being re-evaluated for impact of the new ARS/seismic criteria requirements.
Modifications resulting from this re-evaluation will be implemented in accordance with the above requirements.
a Phase 2 (Post-Restart)
The scope for Phase 2,of this program is seismic class I, Unit 2 and common small bore piping and'supports outside the Design Baseline Program Safe Shutdown Restart
- Boundary, which includes an estimated total of 8,000 ft. of piping and 1,200 supports.
This remaining seismic class I piping will be evaluated post-restart.
As in Phase 1,
an attributes walkdown and further
. evaluations will be performed to identify the piping and supports which do not meet design criteria'tems which do not meet the design criteria will be modified prior to the Unit 2 Cycle 6 restart.
CRITERIA Interim operability criteria BFN-50-C-7303 and long term design criteria BFN-50-C-7103 and BFN-50-C-7107 are being used for this program.
These criteria have previously been reviewed by the NRC staff.
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Enclosure 2
List of Commitments BFN Unit 2 Small Bore Piping 1.
Pre-Restart Small bore program scope is the Seismic Class I, Unit 2 and common small bore piping and supports within the Design Baseline Program Safe Shutdown Restart Boundary.
Items within this boundary which do not meet the interim operability criteria will be modified to meet the long term criteria prior to restart.
2.
Perform modifications to small bore piping and supports, resulting from re-evaluations of existing work, following revisions to the seismic long term design criteria and new Seismic Amplified Response Spectra.
Modifications resulting from this re-evaluation will be implemented in accordance with the above defined requirements.
3.
Post-Restart Small bore program scope is Seismic Class I, Unit
.2 and common small bore piping and supports outside the Design Baseline-Program Safe Shutdown Restart Boundary.
-An attributes walkdown wi 11 be performed to identify the piping and supports which do not meet design criteria.
Items which do not meet the design criteria will be modified prior to the unit 2 cycle 6 restart.
4.
Smal,l bore commodities from the pre-restart scope (items 1
and 2 above) which do not meet the long term design criteria, but are within the interim operability criteria will be modified prior to the unit 2 cycle 6
restart.
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