ML20154J301
| ML20154J301 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 05/19/1988 |
| From: | Gridley R TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| EA-86-056, EA-86-56, NUDOCS 8805260287 | |
| Download: ML20154J301 (9) | |
Text
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,e TENNESSEE VALLEY AUTHORITY CHATTANOOGA. TENNESSEE 37401 SN 157B Lookout Place MAY 191988 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C.
20555 Gentlemen:
1 In the Matter of
)
Docket Nos. 50-259 Tennessee Valley Authority
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50-260
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50-296 BROWNS FERRY NUCLEAR PLANT (BFN) UNITS 1, 2 AND 3 - NRC INSPECTION REPORT 1
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NOS. 50-259/86-56, 50-260/86-56, AND 50-296/86-56, - SUPPLEMENTAL RESPONSE This letter contains a supplemental response to EA 86-56, Item I.A.
Since October 8, 1986, when TVA's original response was forwarded. TVA has identified inadequacies in the design control of cable tray loading at BFN.
The BFN senior resident inspector was informed of the problem in November. provides TVA's supplemental response. provides a list of commitments.
If you have any questions, please telephone David Skridulis at (205) 729-2070.
Very truly yours, j
TENNESSEE LLEY AUTHORITY R. Gridley,.D rector Nuclear Licensing and Regulatory Affairs Enclosures cc: See page 2 0
8805260287 880519 PDR ADOCK 05000259 Q
DCD An Equal Opportunity Employer
U.S. Nuclear Regulatory Commission hlfky{h)hhh 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, NW, Suite 2900 Atlanta, Georgia 30323 Mr. G. G. Zech Assistant Director for Projects TVA Projects Division U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852 Browns Ferry Resident Inspector Browns Ferry Nuclear Plant Route 12, Box 637 Athens, Alabama 35611
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e TENNESSEE VALLEY AUTHORITY CHATTANOOGA, TENNESSEE 37401 SN 157B Lookout Place 3dl%Y 191988 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C.
20555 Gentlemen:
In the Matter of
)
Docket Nos. 50-259 Tennessee Valley Authority
)
50-260
)
50-296 BROWNS FERRY NUCLEAR PLANT (BFN) UNITS 1, 2, AND 3 - NRC INSPECTION REPORT NOS. 50-259/86-56, 50-260/86-56, AND 50-296 /86-56,.- SUPPLEMENTAL RESPONSE This letter contains a supplemental response to EA 86-56, Item I.A.
Since October 8,1986, when TVA's original response was forwarded, TVA has identified inadequacies in the design control of cable tray loading at BFN.
The BFN senior resident inspector was informed of the problem in November. provides TVA's supplemental response. provides a list of connitments.
If you have any questions, please telephone David Skridulis at (205) 729-2070.
Very truly yours,
)
TENNESSEE sLLEY AUTHORITY l
R. Gridley, D rector Nuclear Licensing and
{
Regulatory Affairs 1
Enclosures cc:
See page 2 i
An Equal Opportunity Employer
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t,.
- U.S. Nuclear Regulatory Connission hlf(y { h 'jhhh cc (Enclosures):
Mr. K. P. Barr, Acting Assistant Director for Inspection Prograns TVA Projects Division.
U.S. Nuclear Regulatory Commission Region II 101 Marietta Street, (TW, Suite 2900 Atlanta, Georgia 30323 Mr. G. G. Zech, Assistant Director for Projects l
TVA Projects Division U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852 Browns Ferry Resident Inspector Browns Ferry Nuclear Plant Route 12, Box 637 Athens, Alabama 35611
Y 4
ENCLOSURE 1 SUPPLEMENTAL RESPONSE NRC ENFORCEMENT ACTION No. 50-259/86-56, 50-260/86-56, AND 50-296/86-56 LETTER FROM DR. J. NELSON GRACE TO S. A. WHITE DATED SEPTEMBER 8, 1986
' Item I.A.
Technical Specification 5.6, Seismic Criteria, specifies that station Class I structures and systems are designed to withstand a design basis earthquake.
10 CFR Part 50, Appendix B, Criterion III, Design Control, requires that measures be established to assure that applicable requirements are correctly translated into specifications, drawings, procedures, and instructions and that these measures include provisions to assure that appropriate quality standards are specified and included in design documents. These design control measures must also provide for verifying or checking the adequacy of the design.
Contrary to the above, as of the NRC inspection conducted August 12 - 16, 1985, design discrepancies existed that indicated that some of the cable tray supports in areas of the Control Bay, Diesel Generator and Reactor Buildings, station Class I structures or systems, were not adequately designed to withstand a design basis earthquake and may not have been able to perform their intended function during a seismic event.
In addition, a number of design calculations used to qualify many of the typical cable tray supports were not checked or verified.
Original Response 1.
Admission or Denial of the Alleged Violation TVA does not contest the violation.
2.
Reasons for tle Violation
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Inadequate design controls resulted in a failure to coordinate design requirements within and between engineering disciplines. This lack of design control also resulted in engineering calculations which were not adequately prepared nor properly documented.
3.
Corrective Steps Which Have Been Taken and Results Achieved Nuclear Engineering Procedures (NEP), were issued in July 1986. The stringent NEPs place rigorous controls on the design process of cable tray systems in the following areas:
NEP 3.1, Engineering Calculations NEP 3.2, Design Input NEP 3.3, Interface Control NEP 5.1, Design Output NEP 5.2, Review and Design Verification NEP 6.1, Change Control
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l The result of the NEPs is a closely controlled design process which will ensure the adequate design and verification of seismic qualification of cable tray support systems.
In order to ensure that engineering personnel are qualified to perform design activities on cable tray systems, periodic training in all pertinent documents.and procedures is required.
Individual training records are maintained for each person to ensure that the latest requirements or revisions to documents are made known.
Periodic internal audits are conducted to verify training and design compliance.
The following discussion outlines seismic cable tray programs which are being implemented to (1) allow restart and safe operation of unit 2 and (2) provide seismic qualification of cable trays for all three Browns Ferry Nuclear Plant (BFN) units. These two programs have taken into consideration the overfilled cable trays specified in violation I.B.(1.).
1.
To verify that cable tray supportc are adequate to allow restart and interim operation of unit 2, TVA contracted United Engineers and Contractors (UE&C) to perform an interim seismic qualification of the unit 2 cable tray system. UE&C issued a formal report containing support qualification calculations and modifications required before uait 2 restart.
This report is presently under review by NRC.
Those modifications identified will be completed before restart of unit 2.
2.
For the long-term resolution of cable tray integrity BFN is planning to use the methodology of NUREG-1030 which was developed to resolve Unresolved Safety Issue A-46, Soismic Qualification of Equipment in Operating Nuclear Power Plants. This method of resolution, jointly developed by NRC and the Seismic Qualification Utility Group (SQUG),
uses the results of damage surveys conducted in conventional power plants and industrial facilities which have experienced actual earthquake ground motions.
The surveys show that nonnuclear grade equipment similar to that in nuclear plants, including cable trays, is seismically rugged in general and does not f ail under seismic loading. Direct comparison, using qualification criteria jointly developed by NRC SQUG, will be used to show long-term qualification of BFN cable trays.
TVA contracted Earthquake Engineering (EQE) to evaluate all BFN cable trays for the long-term resolution of concerns regarding the integrity of cable tray supports under seismic loading.
Based on preliminary results of EQE's review, all BFN cable trays would withstand design basis seismic events without modification and continue to function normally.
4.
Corrective Steps Which Will Be Taken to Avoid Further Violations The Nuclear Performance Plan (NPP), Volume 1 provides the actions being implemented at the corporate level to avoid the root cause of inadequate design control. The actions rela'ted to the improvement in the design control process for BFN are contained in the NPP, Volume 3.
Specific corrective steps for this issue are:
a.
The cable tray modifications for unit 2 will be completed using the interim seismic qualification, b.
The long-term qualification of cable trays will be completed using the methodology of NUREG 1030 to resolve Unresolved Safety Issue A-46, Seismic Qualification of Equipment in Operating Nuclear Power Plants.
5.
Date When Full Compliance Will Be Achieved Seismic qualification (including any modifications required) of the unit cable tray systems or common cabic tray systems needed to support the units will be accomplished before their respective startup dates.
Supplemental Response Condition Adverse to Quality Reports (CAQR) initiated in June 1987 identified the fact that the design control of cable tray loading after the August 1985 UE&C seismic qualification report was not adequate.
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UE&C evaluated the cable trays and supports for the as found condition as of l
August 1985 but did not account for the weight of cables for design complete modifications which were in progress or which would be worked before unit 2 restart. The design controls, that engineering had in place to ensure chat the addition of cables on such modifications would not invalidate UE&C's seismic qualification, were inadequate.
As a result of these CAQRs, engineering placed an interim restraint on the BFN modifications and maintenance organizations on cable pulling in seismic st ructures. A written release is required from engineering before cable may be pulled. BFN will issue, as a supplement. to the NEPs, project specific design controls to ensure adequate control of cable pulling.
These design controls will be in place by July 15, 1988.
Engineering will evaluate those cable trays that have had cable added since issuance of the UE&C report to ensure that those cable trays and supports remain qualified based on the acceptance criteria. This evaluation will be completed by August 1, 1988.
)SURE 2
'AL RESPONSE (NT ACTION NO.
I 16-56, AND 50-296/86-56 2
30N GRACE TO S. A. WHITE f,
- HBER 8,1986
- OMMITHENTS 1
. rays that have had cable added since
.-hat those cable trays and supports
- o criteria. This evaluation will be
- design controls, on cable pulling, by I
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ENCLOSURE 2 SUPPLEMENTAL RESPONSE NRC ENFORCEMENT ACTION NO.
50-259/86-56, 50-260/86-56, AND 50-296/86-56 LETTER FROM DR. J. NELSON GRACE ~TO S. A. WHITE DATED SEPTEMBER 8, 1986 LIST OF COMMITMENTS Engineering will evaluate those cable trays that have had cable added since issuance of the UE&C report to ensure that those cable trays and supports remain qualified based on the acceptance criteria. This evaluation will be completed by August 1, 1988.
Engineering will issue project specific design controls, on cable pulling, by July 15, 1988.
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