ML18033A154
| ML18033A154 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 03/10/1988 |
| From: | Gridley R TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| TAC-00304, TAC-304, TAC-R00304, TAC-R00305, TAC-R00306, TAC-R304, TAC-R305, TAC-R306, NUDOCS 8803170007 | |
| Download: ML18033A154 (11) | |
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ACCESSXON 8BR:8803170007 DOC.DATE: 88/03/10 NOTARIZED: NO FACIL:50-260 Browns Ferry Nuclear Power Station, Unit 2, Tennessee AUTH.NAME AUTHOR AFFILIATION GRIDLEY,R.
Tennessee Valley Authority RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)
DOCKET 05000260
SUBJECT:
Discusses seismic cpxalification of small bore piping forwards "Operability Criteria for Pipe
& Pipe supports...."
DISTRIBUTION CODE:
D030D COPIES RECEIVED:LTRi ENCL 3 SIZE: 0 +
TITLE: TVA Facilities Routine Correspondence I
05000260 g NOTES:G.Zech 3 cy.
1 cy.
ea to: Ebneter,Axelrad,S.Richardson, B.D.Liaw,K.Barr, OI.
Jb ACCELERATED DI IBUTION DEMONSTRATION SYSTEM REGULATORY INFORMATXON DISTRIBUTION SYSTEM RXDS RECIPIENT ID CODE/NAME JAMERSON,C MORAN,D COPIES LTTR ENCL 1
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TOTAL NUMBER OF COPXES REQUIRED:
LTTR 21 ENCL 19
TENNESSEE VALLEYAUTHORITY CHATTANOOGA,'ENNESSEE 37401 5N 157B Lookout Place MAR 10 198II U.S. Nuclear Regulatory Commission ATTN:
Document Control Desk Hashington, D.C.
20555 Gentlemen:
In the Matter of Tennessee Valley Authority Docket Nos.
50-260 BRONNS FERRY NUCLEAR PLANT (BFN) SEISMIC QUALIFICATION OF SMALL BORE PIPING This letter describes the BFN program for the seismic qualification of small bore piping and pipe supports.
This material was requested by R. J. Clark's letter dated July 31, 1986, to S. A. Nhite.
This letter supplements the information provided by R. Gridley's letter dated April 8,
- 1987, and section III.3.7 of revision 1 to the Browns Ferry Nuclear Performance Plan that was transmitted by S. A. Hhite's letter dated July 1, 1987..
Enclosure 1 to this letter describes the BFN program for resolving this issue.
Enclosure 2 provides the BFN interim operability criteria for Class I seismic piping.
TVA requests your review of this program and the issuance of a written statement documenting the programs acceptability.
Please refer any questions regarding this submittal to M. J.
May, Manager, BFN Site Licensing, (205) 729-3570.
Very truly yours, TENNESSEE VALLEY AUTHORITY R.
Gridle, Director Nuclear Licensing and Regulatory Affairs Enclosures cc:
See page 2
8803170007 880310 PDR ADOCK 05000260~
P DCD An Equal Opportunity Empioyer
lt
U.S. Nuclear Regulatory Commission MAR 10 'l988 cc (Enclosures):
Mr. K. P. Barr, Acting Assistant Director for Inspection Programs TVA Projects Division U.S. Nuclear Regulatory Commission Region II 101 Marietta Street, NH, Suite 2900 Atlanta, Georgia 30323 Mr. G.
G. Zech, Assistant Director for Projects TVA Projects Division U.S. Nuclear Regulatory Commission One Hhite Flint, North 11555 Rockvi lie Pike Rockville, Maryland 20852 Browns Ferry Resident Inspector Browns Ferry Nuclear Plant Route 12, P.O.
Box 637
- Athens, Alabama 35611
Enclosure' TENNESSEE VALLEY AUTHORITY BRONNS FERRY NUCLEAR PLANT UNIT 2 SMALL BORE PIPING AND SUPPORTS MARCH 1988 This report provides TVA's plan for specific action to qualify seismic Class I field run small bore piping.
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.
~Back round The majority of the Class I small bore (one-half to two-inch diameter) piping at Browns Ferry Nuclear Plant (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 Piping and 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 re.issued as controlled document BFN-50-712 in 1972.
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.
while 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 underdesigned since their selection was based on th'e tables in the design criteria for schedules 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 The scope of this activity for unit 2 and the required common small bore piping is estimated to be 16,000 ft. of pipe with 750 supporting structures.
The following types of piping are excluded from this evaluation:
/
(a)
Piping reviewed under the long-term torus integrity program (b)
Piping reviewed under 79-14 programB (c)
Control Rod Drive piping
In order to address the concerns regarding the seismic qualification of Class I small bore piping, representative piping problems (approximately 10 percent of the total scope) were selected for evaluation.
The following attributes were considered:
~
High temperature/high pressure systems
~
Large concentrated weights (i.e., valves)
~
Large differential movements (i.e.,
source pipe connections)
~
Seismic non-seismic overlap
~
Schedule 160 piping
~
Plant location
~
Different pipe sizes This evaluation will consist of walkdowns of the selected piping, evaluation of this data to design criteria requirements, and review to the operability criteria to determine required modifications.
Those piping and supports which do not meet the design criteria, but are within the interim operability criteria, will be modified to the design criteria after restart.
Those which do not meet the interim operability criteria will be modified to the design criteria unless specifically requested and approved by NRC on a case-by-case basis'efore restarts A comparison of design and operability criteria is summarized in table l.
Attributes will be identified for those supports which require modifications to meet the operability criteria.
These attributes will then be reviewed for generic implications to the entire small bore scope.
The representative scope will be increased as determined necessary by an extensive root cause analysis and evaluation of the extent-of-condition.
This review will address the interdependency of discrepancies and the impact due to the general accumulation of discrepancies.
The design criteria for small bore piping and supports satisfy the FSAR.
Specific requirements for piping and supports are provided in Appendix C of the FSAR.
Licensin Issues Issue:
This program involves the use of interim operability criteria for piping and supports.
Justification:
This criteria assures structural integrity of the piping and supports and is used for the 79-14 program, CEB-CI 21.97.
The criteria are similar to that approved on Sequoyah Nuclear Plant for large bore supports.
Approval of the Sequoyah operability criteria is documented in NUREG 1232.
The small bore qualification program is comprehensive and provides assurance that piping and supports will,remain functional.
Modifications required to meet design criteria will be implemented before start up after the next refueling outage.
TABLE 1
BROHNS FERRY UNIT 2 SMALL BORE PIPING CRITERIA COMPARISON CHART COMPONENT
~P1 in Primary Primary E Secondary Concrete Expansion Anchors Factor of Safety Hedge and Shell DESIGN CRITERIA 1.8Sg SA + Sg Hedge Type 4
Shell Type 5 for Tension 4 for'Shear OPERABILITY CRITERIA 2Sy ASME EQ 11 or Augmented Fatigue Evaluation All Types 2
Pipe Support Tensile and Flexural Stress 1.5 X AISC Maximum Limit 0.9Sv Lesser of 0.7S< or 1.2Sv Compressive Stress 1.5X AISC Maximum Limit 0.9S~
Maximum Limit 0.9P<R Allowable Shear Stress Maximum Limit 0.52Sy Lesser of 0.42S>
0.72Sy Stress Bolt 0.56Su Greater of 0.7S<
or S> (Minimum)