ML18033A336
| ML18033A336 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 08/23/1988 |
| From: | Gridley R TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| TAC-00023, TAC-00296, TAC-00299, TAC-00302, TAC-23, TAC-296, TAC-299, TAC-302, NUDOCS 8808290116 | |
| Download: ML18033A336 (12) | |
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ACCEIZRATED MSIRIBUTION DEMONSTRATION SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)
ACCESSION NBR:8808290116 DOC.DATE: 88/08/23 NOTARIZED: NO DOCKET FACIL:50-260 Browns Ferry Nuclear Power Station, Unit 2, Tennessee, 05000260 AUTH.NAME AUTHOR AFFILIATION GRIDLEY,R.
Tennessee Valley Authority I
RECIP. NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)
II 05000260 NOTES:1 Copy each to: S.Black, J.G.Partlow, S.Richardson B.D.Llaw,F.McCoy.
SUBJECT:
Forwards response to 880726 ltr re seismic program interim operability criteria safety evalaution open item 6 concerns.
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TITLE: TVA Facilities Routine Correspondence R
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TENNESSEE VALLEYAUTHORlTY CHATTANOOGA. TENNESSEE 37401 5H 157B Lookout Place We 28 1888 U.S. Huclear Regulatory Commission ATTH:
Document Control Desk Mashington, D.C.
20555
/
Gentlemen:
In the Matter of Tennessee Valley Authority Docket No. 50-260 BROGANS FERRY HUCLEAR PLANT (BFH) RESPONSE TO SEISMIC PROGRAM INTERIM OPERABILITY CRITERIA SAFETY EVALUATION OPEN ITEMS AHD CONCERNS (TAC 00023,
- 00296, 00299, 00302)
This letter provides TVA's response to your letter from S. Black to S.
A. Mhite, dated July 26, 1988.
In your letter, TVA was requested to provide within 30 days a submittal addressing:
(1) consideration of the tangential component of the relative seismic displacement between the two ends of the radial platform support beam in the platform evaluation; (2) the use of Fy/(0.75 x 2.3) as the interim allowable stress for conduit; and (3) buckling criteria for aluminum conduits and HVAC ductwork.
In addition, TVA was also requested to address the staff's other concerns as discussed in Section 3.0 of the Safety Evaluation.
TVA's response to each of these open items and concerns is provided as Enclosure 1 to this letter.
In addition, TVA has provided comments to Section 2.0 of the Safety Evaluation as Enclosure 2 to this letter.
A listing of commitments made in this submittal is provided as Enclosure 3 to this letter.
Please refer any question regarding this submittal to M. J. May, Manager,
- BFH, Site Licensing, (205) 729-3570.
Very truly yours, TENNESSEE VALLEY AUTHORITY R.
Gr ley,, Manag r,.
Nuclear Licensing, and Regulatory Affairs Enclosures cc:
See page 2
3808290ll6 880823 PDR ADOCK 05000260 P
PDC An Equal Opportunity Employer
1
U.S. Huclear Regulatory Commission cc (Enclosures):
Hs.
S.
C. Black, Assistant Director for Projects TVA Projects Division U.S. Huclear Regulatory Commission One Mhite Flint, Horth 11555 Rockville Pike Rockville, Maryland 20852 Hr. F.
R. HcCoy, Assistant Director for Inspection Programs TVA Projects Division U.S. Huclear Repulatory Commission Region II 101 Harietta Street, HM, Suite 2900 Atlanta, Georgia 30323 Broom Ferry. Resident Inspector Browns Ferry Huclear Plant Route 12, Box 637
- Athens, Alahama 35611
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ENCLOSURE 1 RESPOHSE TO SAFETY EVALUATION OPEH ITEMS AHD CONCERNS Saftey Evaluation Section 3.1 Lower Drywell"Steel Platforms HRC Concetax:
"Establish a project procedure for the control of additional loads that might. be imposed to the platforms resulting from modification activities during, plant operation to justify the use of a live load L = 0 in the restart evaluation."
Procedure 2-GOI-200-2 "Drywell Close Out" ensures that trash, loose tools or equipment, scaffolding, and temporary hoses, lighting and shielding are removed from the drywell before drywell closure.
After drywell closure, the drywell is inerted with nitrogen and as such no modification activity, and thus no live load, can occur during plant operation.
HRC Concern:
"Justify, under the DBVP program, that the exclusion of the jet impingement load Yj does not constitute a violation of the FSAR requirements for lower steel platforms."
TVA Res onse:
It is TVA's understanding that HRC will identify this concern in the Inspection Report from the April 18-22, 1988 review of Browns Ferry's Design Baseline Verification Program.
TVA will respond to open items which are identified in that Inspection Report'.
HRC Concetm:
"Include the tangential component of the relative seismic displacement between the two ends of the radial platform support beams in the platform restart evaluation."
TVA Res onse:
TVA will evaluate the effect seismic displacement between beams before restart.
Based overall structural integrity affected.
of the tangential component of the relative the two ends of the radial platform support'n our initial assessment, TVA feels that the of the platform steel will not be adversely
HRC Concern:
"In addition, as a post-restart
- item, TVA is required to address the adequacy of applying the 1978 edition of 6he AISC Specification for the restart evaluation of the platforms with respect to the FSAR design criteria which were based on the 1963 AISC Specification."
TVA Res onse:
TVA will, as a post-restart item, address the adequacy of applying the 1978 edition of the American Institute of Steel Construction (AXSC) specification with respect to the Final Safety Analysis Report (FSAR) design criteria which were based on the 1963 AISC specification.
Safety Evaluation Section 3.2 Miscellaneous Steel HRC Concern:
"Consideration of the tangential component of the relative seismic displacement between the two ends of the radial platform support beams in the restart evaluation of the upper steel platform."
TVA Res onse:
The upper, steel platforms are cantilevered off the sact'ificial shield wall and therefore have no restraint from the drywell wall on the opposite end of the radial beams.
Subsequently, there are no relative seismic displacements associated with the upper drywell platforms.
Safety Evaluation Section 3.3 Electrical Conduit and Conduit Supports HRC Concern:
"The use of 2.0 x Fy/(0.75 x 2.3) as the interim allowable stress for conduit is not acceptable.
TVA should use the allowable accepted for SQH 2 restart, Fy/(0.75 x 2.3)."
TVA Res onse:
TVA contends that the use of 2.0 x Fy/(0.75 x 2.3) is an acceptable stress level for the purposes of restart.
This is based upon the following:
- 1. This stress allowable is equivalent to the operability stress criteria for piping.
This allowable is less than 0.7Fu which has been allowed
for steel structures.
- 2. This stress allowable is equivalent to the faulted requirements as specified in the American Society of Mechanical Engineers (ASME) Code, 1986 Subsection HD3653 and Subsection HD3655.
HRC Concern:
"TVA should provide buckling criteria for aluminum conduits."
TVA Res onse:
TVA does not consider a buckling evaluation of aluminum conduit to be a
standard design practice nor a critical failure mode.
Full scale shaker table tests have been performed on aluminum conduit at seismic levels in excess of twice the BFH design basis earthquake and no failures were observed due to buckling of conduit.
Safety Evaluation SE Section 3.4 HVAC Ductwork and Supports NRC Concern:
The staff found the interim criteria for the HVAC ductwork and duct supports acceptable, pending TVA's submittal of buckling criteria for the ductwork.
TVA Res onse:
Browns Ferry's IIVAC ductwork was originally designed and built to Sheet Hetal and Air Conditioning Hational Association (SMACNA) standards.
.The current SHACHA standards, and the SHACHA standards at the time BFN was licensed for operation, do not require an evaluation for buckling.
TVA's initial assessment is that an evaluation for buckling will not yield any additional modifications beyond that which would be required to meet the existing design criteria.
TVA will perform a study to verify the adequacy of the original design criteria before restart.
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V k
ENCLOSURE 2 COHHENTS ON SAFETY EVALUATION SECTION 2.0 Section 2.1 Drywell Access Steel Platforms Subparagraph 2.1 d states "During the May 18, 1988 meeting, TVA committed to combine these dynamic reactions on an absolute sum basis, regardless of their phase relationship."
TVA Comment:
As committed to in the meeting, TVA will, before restart, revise the operability criteria to reflect that the absolute summation of loads was utilized, for. the restart evaluation of the Drywell Access Steel Platforms.
- However, TVA plans to utilize phasing of the seismic loads for it's long;term evaluation of the drywell platforms and will reflect this in the long-term criteria.
Section 2.2 Miscellaneous Steel Subparagraph 2.2a states that the interim criteria for the structural members is acceptable.
TVA Comment:
The criteria utilizes 0.9Fcr, whereas the safety evaluation refers to 0.8Fcr.
It, appears that, 0.8Fcr in the safety evaluation was a
typographical error.
TVA requests NRC concurrence that. 0.9Fcr is acceptable for the interim criteria.
ENCLOSVRE 3 LISTIHG OF COHHITHEHTS 1)
TVA will evaluate the effect of the tangential component of the relative seismic displacement between She two ends of the radial platform support beams before restart.
2)
TVA will, as a post-restart item, address the adequacy of applying the 1978 edition of the AISC specification with respect to the FSAR design criteria which were based on the 1963 AISC specification.
3)
TVA's initial assessment.
is that an evaluation for HVAC buckling will not yield any additional modifications beyond that which would be required to meet the existing design criteria.
TVA will perform a study to verify the adequacy. of this original design criteria before restart.