ML18033A792
| ML18033A792 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 06/13/1989 |
| From: | Michael Ray TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| TAC-00319, TAC-319, NUDOCS 8906230076 | |
| Download: ML18033A792 (15) | |
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.ACCESSION NBR;8906230076 DOC.DATE: 89/06/13 NOTARIZED:
NO FACIL:50-260 Browns Ferry Nuclear Power Station, Unit 2, Tennessee AUTH.NAME AUTHOR AFFILIATION RAY,M.L.
Tennessee Valley Authority RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)
SUBJECT:
Forwards revised plan to qualify CRD hydraulic piping sys, including insert a withdrawal piping, valves 6 supports.
DISTRIBUTION CODE: A048D COPIES RECEIVED:LTR I
ENCL f
SIZE:
TITLE: OR/Licensing Submittal:
Equipment Qualification NOTES:1 Copy each to: S.Black,D.M.Crutchfield,B.D.Liaw, R.Pierson,B.Wilson DOCKET g
05000260 05000260 RECIPIENT ID CODE/NAME SIMMS,M GEARSFG INTERNAL: ACRS NRR/DEST/MEB 9H NUDOCS-ABSTRACT OGC/HDS2 RES/DSIR/EIB COPIES RECIPIENT LTTR ENCL ID CODE/NAME 1
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EXTERNAL: LPDR NSIC NOTES:
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TENNESSEE VALLEYAUTHORITY CHATTANOOGA. TENNESSEE 37401 5H 157B Lookout Place VUN Is e9 U.S. Nuclear Regulatory Commission ATTN:
Document Control Desk
'blashington, D.C.
20555 Gentlemen:
In the Hatter of Tennessee Valley Authority Docket Ho.
50-260 BROGANS FERRY HUCLEAR PLAHT (BFN) UNIT 2 SEISHIC QUALIFICATION OF THE COHTROL ROD DRIVE HYDRAULIC (CRDH) PIPING SYSTEH This letter describes the program fox the Seismic Qualification of the Browns Ferry Unit 2 CRDH piping system, which includes the CRD insert and withdrawal piping, valves, and piping supports.
As discussed duxing the HRC/TVA meeting of February 17, 1989, staff review oE the proposed CRDH criteria would initiate only upon receipt of finalized inEormation.
TVA agreed at that time to formally submit the CRDH design cxiteria with justification, and to provide an associated implementation schedule.
The enclosed Eulfills that earlier commitment.
This information supplements that previously submitted by letter dated Harch 17, 1988.
HRC review of the enclosed criteria is requested.
As an
- assist, TVA personnel are available to support a working meeting on this issue, at the HRC staff's convenience.
Please refex an questions regarding this submittal to Patrick P. Cariex, Hanager of Site Licensing, (205) 729-3570.
Very truly yours, TENNESSEE VALLEY AUTHORITY Manag x, Nuc ea icensing and Regulatory AfEairs Enclosures cc:
See page 2
Scy06230076 85000260 8qpbl3
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An Equal Opportunity Ernpioyer
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U.S. Hucleax Regulatory Commission cc (Enclosures):
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S.
C. Black, Assistant Director for Projects TVA Projects Division U.S. Huclear Repulatory Commission One 'N>ite Flint, Hoxth 11555 Rockville Pike Rockville, Haryland 20852 Hr. B. A. 'Hilson, Assistant Directox for Inspection Programs TVA Projects Division U.S. Huclear Regulatory Commission Region II 101 Harietta Street, HW, Suite 2900 Atlanta, Georgia 30323 HRC Resident, Inspector Brows Ferry Huclear Plant Route 12, Box 637
- Athens, Alabama 35609-2000
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t TENNESSEE VALLEY AUTHORI'Y BROMHS FERRY NUCLEAR PLAHT UNIT 2 (BFN-2)
SEISMIC QUALIFICATION OF THE CONTROL ROD DRIVE HYDRAULIC (CRDH) PIPING SYSTEM This report provides TVA's revised plan to qualify the BFN-2 CRDH piping system to seismic class I requirements.
It, supplements and updates the March 17, 1988, submittal from R. Gridley to US HRC entitled, "Seismic Qualification of Control Rod Drive Insert and Mithdrawal Piping."
An executive
- summary, located at the end of this report, provides a current overview of the BFH-2 CRDH Program.
BACKGROUND The CRDH piping system analysis has been the subject of significant discussions between TVA and the HRC staff since May 15, 1986, when TVA initially proposed specific guidelines for rigorous analysis of the system.
A background summary in the referenced March 1988 submittal recaps the CRDH analysis history until that time.
At the civil/seismic criteria meeting of February 17,
As requested by the HRC, this report describes and justifies the new CRDH design criteria as well as TVA's pre-restart plan for implementing it. for BFH-2.
SCOPE The BFH-2 CRDH Program encompasses all CRD insert and withdrawal piping, valves, and piping supports for unit 2 from the point of piping attachment to the hydraulic control unit-in the reactor building to the point of piping attachment to the control rod drive housings below the reactor vessel.
DESIGH CRITERIA The proposed long term criteria for analysis of CRDH piping and supports are BFH-~0-C-7103 and BFH-50-C-7107, respectively.
The interim operability criteria for CRDM piping and.,upports is BFN-50-C-7303.
Finally, the design criteria for evaluation of the equipment and drywell inter. faces are BFH-50-C-7105 for equipment and BFH-50-C-7100 Attachments A and D for the drywell.
The BFN-50-C-7303, BFH-50-C-7105, and BFN-50-C-7100 criteria have been previously reviewed by the HRC and they contain no special provisions for the CRDH piping system.
In addition, the HRC has previously reviewed the BFH-50-C-7103 and BFH-50-C-7107 criteria, except for the special provisions for CRDH piping and supports which are delineated in the next two paragraphs,
The special px.'ovisions for CRDH piping, analysis are contained in Table 8.0-1 of criteria BFN-50-C-7103 Attachment A.
The CRDH portion of Table 8.0-1 defines load combinations and allowable stresses Eor rigorous analysis of the CRDH piping.
Note 10 of Table 8.0-1 identifies the requirement fox analyzing
<<epresentative lines in the CRDH pipe bundles and it defines the basis for designating suppox.t loads from Uxose analyses.
Note ll oE Table 8.0-1 establishes requirements fox. defining and evaluating support and pipe loads due to sei..mic impacts where the pipe guides have been removed due to thermal expan-ion considerations.
The special provisions for CRDH support analysis are contained in Notes 4 and 6 oE Table 1.4.2.1 and in Section 1.4.2.5.1 of criteria BFN-50-C-7107.
Note 4
of Table 1.4.2.1 requires the normal scram thermal condition to be combined with the seismic events, and it defines additional load cases for analysis of abnormal scram (including leaking valve) thermal conditions.
Note 6 of Table 1.4.2.1 defines special consider.'ations for evaluating CRDH support stress and load effects, accounting for the fact that the peak seismic forces from the individual pipes in a CRDH bundle will not occur simultaneously.
- Finally, Section 1.4.2.5.1 serves to enforce proper interaction of the CRDH piping analyst and support designer.
JUSTIFICATION FOR DESIGN CRITERIA SPECIAL PROVISIONS The provisions Eor CRDH piping analysis load combinations and allowable stresses in BFN-50-C-7103 Attachment A Table 8.0-1 are consistent with the rigorous piping analysis philosophy in Appendix C of the BFN FSAR.
FSAR Table C.0-6 sheets 7 and 9 will be revised in the next annual update to x;eflect this information because these sheets now x.eflect compliance with the alternate analysi" criteria described in FSAR Section C.3.2.1b.
This revision is justified because x.igorous analysis to this design cx.'iteria is in accordance with FSAR Section C.3.7.la which is a more precise and complete analytical approach.
The provisions for rigorou., analysis of r.epresentative CRDH pipes in BFN-50-C-7103 Attachment A Table 8.0-1 Note 10 ensure conservative calculation of pipe stresses and support loads, consistent with the standard requirements of this criteria for individual pipes.
The provi.,ions for defining and evaluating seismic impact loads on CRDH support bax;s in BFN-50-C-7103 Attachment A Table 8.0-1 Note 11 a<<e justified because the impact forces ax;e calculated conservatively, based upon the pipe velocity attained fx.om a linear elastic analysis assuming no seismic restraint at the impact location.
The impact load effects are conservatively evaluated in the local pipe stress calculations per this note.
Then the impact load effects are combined with other seismic load effects on the supports according to BFN-50-C-7107 Table 1.4.2.1 Note 6.
The provisions for CRDH piping support thermal load combinations and allowable stresses in BFN-50-C-7107 are in compliance with rigorous analysis philosophy of Appendix C of the BFN FSAR.
The thermal conditions are consistent with BFN FSAR Figure 3.4-10 and othe'ertinent FSAR sections.
The provisions for evaluating CRDM support stress and load effects in BFN-50-C-7107 Table 1.4.2.1 Note 6 are justified because the criteria Eor combining seismic load effects Erom the multiple individual pipes on a rack and bar are consistent with the results oE a special study calculation, which is summarized in reference 1.5.2 of the criteria.
The study calculation justifie-a 1.3 multiplication factor for general use in a modified Square Root of the Sum of the Squares (SRSS) stress (load effects) combination technique, with a special case upper limit of (ABSUM + SRSS)/2.
ABSUM =
absolute summation.
In addition, a special case 1.0 multiplication factor is justified for the seismic impact. load effects because those loads are calculated on a conservative basis, as described
- above, and have an extremely low probability of simultaneous occurrence with seismic loads from the other pipes on the same support rack.
Another special case 1.0 multiplication factor for local bar seismic stress evaluation is justified because it sati.fies the standard requirements of BFN-50-C-7107 Section 1.4.2.5.
The provisions of Hote 6 for combining seismic support load effects from different orthogonal direction= and Erom multiple racks on a frame, by absolute sunmation, are inherently conservative and provide additional justification for the modified SRSS seismic stress combination technique.
Finally, the provisions for calculating static load effects, combining static and seismic load effects, and evaluating the combined eEfects are consistent with the basic support design requirements of the BFN-50-C-7107 criteria.
Attachment 1 summarizes major technical provisions of the proposed criteria and the planned 1989 CRD)i analysis.
PRE-RESTART IMPLEMENTATION PLAN TVA plans to implement the new CRDH criteria in a phased approach.
HRC's concurrence with the following pre-restart phase of this implementation plan is reque.ted aEter approval of the criteria.
The CRDH pipes inside and outside of the drywell will be completely reanalyzed and nozzle loads/valve accelerations will be evaluated using the new criteria.
Long-term pipe stress, nozzle load and valve acceleration allowable" are expected to be satisfied for CRDH pipes outside the drywell.
llowever, use of time hi.,tory analysis may be necessary in order to satisfy long term pipe stress criteria for some CRDH pipes inside the drywell.
This time history analysis, if required, will be justified according to established procedure and submitted to the HRC for case by case approval.
It may also be necessary to add lateral supports for the CRD housings to reduce seismic response of the housings and attached CRDH pipes.
The new pipe loads on each existing support frame will be tabulated and compared to the corresponding pipe support loads from the 1986 analysis (Attachment 2).
In addition, two representative worst case support frames (one inside the drywell and one outside the drywell) will be selected and completely reanalyzed to the new criteria. It is expected that no new support frame modifications will be required in order to satisfy tho interim operability criteria, and few, if any, new support frame modifications are expected in order to satisfy long term criteria.
The results from this pre-restart effort will be evaluated, as the work progresses, to determine whether the present expectations are being verified.
If they are not verified, the HRC will be informed and this implementation plan will be appropriately revised to include additional analysis and modificat,ion activities before restart.
Any post-restart modifications will be installed in accordance with previous schedule commitments as restated in the following Executive Sumnery.
EXECUTIVE SUHHARY Hew criteria for analysis of the BFH-2 CRDR piping system are summarized in.
Justification for the special provisions in these. criteria fox.
CRDH analysis has been provided.
In addition, a pre-restart implementation plan for the new criteria has been submitted for HRC's review/concurrence.
Hodifications required to satisfy the interim operability criteria will be installed before restart from the current outage and modifications required to sati fy the long term criteria will be installed before restart from the next refueling outage (cycle 6).
ATTACHMENT 1 1989 CRDH ANALYSIS RIGOROUS ANALYSIS FOR ALL FSAR LOADS LOAD COMBIHATIOHS PER FSAR PHILOSOPHY ALLOb1ABLE STRESSES PER HEM CRITERIA CLOSE-FIT liOUSHER SEISMIC XHPUT TO BUILDING MODEL SEISMIC SPECTRA FROM MUL'TI-BRANCliBUILDIHG MODEL BROADEHED SPECTRA. + 10 PERCEHT ENVELOPED SPECTRA OR IHDEPEHDEHT SUPPORT MOTION VERTICAL SPECTRA CORRESPONDING TO liORIZOHTAL SPECTRA REPRESEHTATXVE PIPE MODELS IHSIDE/OUTSIDE DRXHELL 0.5 PERCENT DAMPING FOR DBE ANALYSIS 2 DIMEHSIOHAL EARTHQUAKE ABSUM COMBIHATIOH FOR DIRECTIONS AHD R.G. 1.92 FOR MODES
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RIGID RESPONSE (ZPA) ANALYSIS BY MISSING MASS OBE RESPONSE
= 1/2 DBE RESPONSE SEISMIC IMPACT LOADS MHERE GUIDES/CLAMPS REMOVED FRICTIOH LOADS CONSIDERED, F = 0.3 SCRAM AHD LOCA TliERMAL ANALYSIS MODIFIED SRSS SEISMIC LOAD EFFECTS COMBINATION FOR SUPPORTS SUPPORT DISPLACEMENT LIMIT FOR PIPE LOAD = 1/8 INCli
ATTACHMENT 2 1986 CRDli ANALYSXS RIGOROUS ANALYSIS FOR ALL FSAR LOADS LOAD COMBIHATIOHS PER FSAR PHILOSOPHY ALLOblABLE STRESSES PER BFH-50-D707 CRITERIA EL CEHTRO SEISMIC INPUT TO BUILDING MODEL SEISMIC SPECTRA FROM 3-BRAHCli BUILDING MODEL BROADENED SPECTRA + 10 PERCEHT EHVELOPED HORIZONTAL SPECTRA VERTICAL SPECTRA GROUND LEVEL REPRESENTATIVE PIPE MODELS IHSIDE/OUTSIDE DRYMELL 5 PERCEHT DAMPING FOR DBE ANALYSIS 2-DIMEHSIOHAL EARTHqUAKE SRSS COMBIHATIOH FOR MODES AND DIRECTIONS RIGID RESPONSE (ZPA) ANALYSIS OBE RESPONSE
= 2/3 DBE RESPONSE SEISMIC IMPACT LOADS MHERE GUIDES/CLAMPS REMOVED FRICTIOH LOADS CONSIDERED, F = 0.3 SCRAM AHD LOCA THERMAL ANALYSIS COHSERVATIVE SEISMIC LOAD EFFECTS COMBIHATIOH FOR SUPPORTS SEISMIC LOAD SUPPORT DISPLACEMENT LIMIT = 1/8 INCH
ATTAC194EHT 3 1987 CRDH MODXFXCATIONS REQUIRED TO SATISFY 1986 ANALYSIS GUIDELINES/CRITERIA 800 LOCAL STRUCTURAL MODIFICATIONS TO SUPPORTS ADD STRENGTH/STIFFHESS TO SUPPORT FRAMES PRIMARILY BRACES AND COHNECTXOH REINFORCEMEHTS 300 INSIDE DRYWELL 500 OUTSIDE DRYMELL 3000 PIPE GUIDES/CLAMPS REPLACED EHSURE REQUIRED LOAD CAPACITIES AHD GAPS PROVIDE QUALITY INSTALLATIONS A FEW PIPE GUXDES REMOVED ALLOM THERMAL EXPANSION OF PIPES/DRYMELL
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