ML20147D761
| ML20147D761 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 03/02/1988 |
| From: | Michael Ray TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| NUDOCS 8803040148 | |
| Download: ML20147D761 (8) | |
Text
.
TENNESSEE VALLEY AUTHORITY CH ATTANOOGA. TENNESSEE 37401 5N 10SB Lookout Place MAR 2 1988 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C.
20555 Gentlemen:
In the Matter of
)
Docket Nos.
50-327 Tennessee Valley Authority
)
50-328 SEQUOYAH NUCLEAR PLANT (SQN) - INTEGRATED DESIGN INSPECTION (IDI) - NRC INSPECTION REPORT 50-327/87-48 AND 50-328/87-48 Enclosed la TVA's supplemental response to IDI item D4.2-3.
It is our understanding that the supplemental response provided herein completes TVA's actions on this item for SQN unit 2 restart.
If you have any questions, please telephone D. L. Williams at (615) 632-7170.
Very truly yours, TENNESSEE VALLEY AUTHORITY h
M. J. Ra Deputy Director Nuclear Licensing and Regulatory Affairs Enclosure cc:
See page 2 l
8803040148 8R0302 PDR ADOCK 05000327 0
\\}
l An Equal Opportunity Employer l
w
, U.S. Nuclear Regulatory Commission AR 1)1988 Enclosure cc (Enclosure):
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 Division of TVA Projects Office of Special Projects U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852 Sequoyah Resident Inspector Sequoyah Nuclear Plant 2600 Igou Ferry Road Soddy Daisy, Tennessee 37379 l
i
)
s.
i ENCLOSURE SEQUOYAH NUCLEAR PLANT SUPPLEMENTAL RESPONSE TO IDI ITEM D4.2-3 ITEM NO.:
D4.2-3 TITLE: SCV Vertical Response Spectra and Time Step Effect
SUMMARY
OF ITEM:
The seismic analysis of the steel containment vessel, a Category I structure (Reference 1), was performed in 1972 and the seismic report (Reference 2) was subsequently issued on January 24, 1975.
In the winter of 1985, the vertical response spectra were generated and the calculation was considered to be revision 1 of the seismic analysis of the steel containment vessel. Revision 1 of the seismic report was issued on June 22, 1987.
The generated vertical spectra curves show a significant increase in acceleration within the 20 to 30 Hz range at every elevation.
At the higher"containment elevations, vertical accelerations increased seven-to ten-fold. The reasons for the increase are unknown. This leaves in question the technical adequacy of the original methodology used by TVA to perform seismic analyses.
It also leaves in question the adequacy of equipment seismic qualification which have [ sic]
apparently been based on the earlier floor response spectra.
CLASSIFICATION:
Documentation SUPPLEMENTAL RESPONSE:
The response to IDI D4.2-3 on SCV vertical response spectra was submitted to the NRC on December 29, 1987.
During the IDI close-out reviews at TVA's Knoxville, Tennessee, of fice between February 15 and 19,1988, additional information was requested to complete the evaluation of SCV vertical response spectra and time step effects. The requested information included:
1.
Review of a sample of ten piping systems for time step change.
2.
Evaluation of the reactor coolant loop attached branch piping systems for time step change.
3.
Evaluation of effects of secondary vertical peak in auxiliary control building response spectra on equipmeut seismic qualification.
These three items are addressed below:
1 l
l
o
, ITEM NO.:
D4.2-3 SUPPL.EMENTAL RESPONSE:
(Continued)
Review of Ten Piping Systems for Time Step Change Time steps used in the vertical and horizontal seismic analyses were reduced from 0.01 second to 0.005 second to generate a new set of floor response spectra. As expected, the new floor response spectra exceed the original design basis response spectra only in the high frequency region (above 20 Hz),
where primary peaks or secondary peaks are located.
Several piping systems were selected to evaluate the effect of spectrum increases in the high frequency region.
The ten piping systems originally evaluated in N2-PIR-8652-MISC, Rev. 1, were selected for revicw. Three of these ten systems turned out to be trivial cases due to absence of spectra changes. These were subsequently deleted _from further evaluation. Four additional systems (in the interior concrete structure and auxiliary buildings) were selected to achieve the worst possible consequence (see Table D4. 2 1 bel ow). One of these four systems, N2-3-10A, 11A, 12A, was also one of the ten systems used in N2-pIR-8652-HISC, Rev. 1.
Therefore, the total number of systems evaluated was ten.
l Systems l
)
l l
l l
l ICS l
ICS l
AB l
AB l
l Selection l0600154-03-01 l 0600154-07-03 l N2-64-2A l N2-3-10A,11A,12A l l Criteria l
l l
l l
l l
l l
l l
l Systems with l l
l l
l l low stress l
l l
X l
X l
l margins l
l l
l l
l l
l l
l l
l Modal fre-l l
l l
l lquencies in l
l l
l l
lthe region l
X l
X l
l l
lof spectrum l
l l
l l
lvalue increasel l
l l
l l
l 1
l l
l l Systems with l l
l l
l lhigh contri-l l
l l
l lbution of l
X l
X l
X l
X l
l seismic load l
l l
l l
l l
l I
l l
l System l
l l
l l
l supports l
l l
l l
l qualified by l
X l
X l
X l
X l
lCEB-CT-21.89 l
l l
l l
l l
l l
l l
Table D4.2-3-1:
"Worst Case" Attributes of Selected Systems DNE4 - 2859Q NTB - 2/28/88
o l 1 The time step change affected only the acceleration floor response spectra in the high frequencies region where spectrum displacement change is too small to be felt by piping systems or equipment.
In spite of this, the conservative linear elastic response spectrum method was used to evaluate the acceleration spectra change.
As shown in Tables D4.2-3-2A and B, the changes have no impact on SQN unit 2 restart.
Evaluation of RCL Attached Branch Piping Systems for Time Step Change Additional information on the Reactor Coolant Loop (RCL) response spectra is being submitted to the NRC under separate cover regarding SQN - Resolution of Open Inspection Issues.
Evaluation of Effects of Secondary Vertical Peak in Auxiliary Control Building Response Spectra on Equipment Seismic Qualification The additional information requested by the NRC regarding equipment seismic qualification is related to anchorage evaluations performed for IDI issue D4.6-1 (equipment anchorages) and IDI issues D3.4-3 and D3.4-4 (Category I heat exchangers).
With regard to the qualification of equipment anchorages, 60 components were reviewed for resolution of IDI issue D4.6-1.
Seven of these are located at the highest elevations of the auxiliary control building.
Each of the calculations for these seven anchorages was reviewed to determine whether the new spectra will affect the anchorage load calculation.
The results are summarized below:
ITEM DESCRIPTION
- ELEV, ANCHORAGE LOAD NO.
CALCULATION METHOD (1) 62 COMPRESSOR 763' RIGID - ZPA UNIT (2) 63 CONDENSER 763' PEAK OF ARS/ RIGID-ZPA (3) 164 EKHAUST FAN 763' PEAK OF ARS (4) 156 EKHAUST FAN 763' PEAK OF ARS (5) 46 TRIP CABINET 759' RIGID - ZPA (6) 50 POWER SUPPLY 759' PEAK OF ARS PANEL j
(7) 52 TRANSFORMER 759' PEAK OF ARS 1
l
L,
, None of the above anchorage calculations is affected by the new spectra since all are based on either the peak of the spectra, the ZPA acceleration, or both.
With regard to qualification of the heat exchangers (IDI issues D3.4-3 and D3.4-4), two Category I heat exchangers were identified for evaluation on the basis of having the highest anchorage stresses. The purpose of the review was to examine the effect of the revised spectra on the two heat exchangers showing the smallest design margins, i.e., the containment spray and the component coolant water (CCW).
The containment spray heat exchanger is located at elevation 713'-6" of the auxiliary control building.
Per calculation, the vertical mode frequency is 19.3 Hz.
The digitization of the original spectra used in the analysis yields a spectral acceleration of 0.214 C.
Using the new broadened spectra with a 0.005-second time step gives a vertical SSE acceleration of 0.146 C.
Therefore, the analysis is conservative relative to the new spectra. The difference is a result of additional conservatism built into the original design spectra.
The CCW heat exchanger is located at elevation 713'-6" of the auxiliary control building.
The calculation d2 fines three critical modes lying between 8.8 and 12.5 Hz.
f.te effect of the new spectra is again to reduce the responses celative to the spectra used in the analysis because of additional conservatism built into the original design spectra. Thus, the effect of this issue on the equipment seismic qualification is negligible.
In conclusion, the three additional items requested for IDI issue close-out have no impact on SQN unit 2 restart.
t I
I
- 9. *.
c-
\\
-S-1 TTEM NO.:
D4.2-3 l
SUPPLEMENTAL RESPONSE (Continued)
The results of the 10 system evaluations are presented in Table D4.2-3-2A and B below:
l Systems l l
l l
l l
Cogonent N2-70-2R 0600154-07-03 N2-64-2A 0600154-01-01 0600154-03-01 l
lSCV'CS lICS-SB-RCL lSCV-AB lSCV-AB.
lICS-SB-RCL l
l l
l 1
l l
l l
l l1C5-692-712 lSCV-760 lSCV-841.0No l1C5-692-712 l
l Applicable lSCV-715.29 lShieldBldg.,lNochange l change.
lShieldbuilding,j l Spectra /
l1C5-692-702 lRCL lAB-748-762 lAB-688.5-732.5 lRCL l
l Elevation l
1 I
l
[
l l
I I
I I
l lPipeStresseslIncreasedby lSlightDecreaselMaxstress lMaximumpipe lOveralldecrease*l l
l1400 PSI <
jinpipestress*linc.<200 l stresses l
l l
lfaultedallowl l PSI l decrease
- l l
l lEQ.9F l
l negligible l
l l
l 1
I I
I I
l l
1 l
l l
l l
l Penetration l Increase <1%l Nones.B.
l Increase lIncreaseless lSCVpenet. loads l l Loads l
lanchoroveralllonly2lbs. lthan1%
l increase <3.6%
l-l l
l decreased l<1%
l negligible linX,overall l
l 1
1 1
I I neolial.ble l
l l
l l
l 1
I i
l Nozzle lNone l3 nozzles lNone lNozzleloadson lHotlegnozzle l
l Loads l
l increases l
lHXC1Aincrease lloaddecreased* l l
l lnegligilbe l
lby1%, increase l l
l l
1 < 1%
l Inealloible 1
l l
l l
l l
-l l
l Valve lMostdidnot lIncreaseminor] Increase <
l Increase minor on] Increase < 10% = l j
l Accelerations l change,two lonallvalvesl5% max lallvalves,stilll0.25G,valveok l i
l l increased <
lstillmeet3G/ltotalaccel l meet 3G/2G lfor3G/2G l
l l 5%
l 2G Allowables l< IG lallowables l
l l
lOnesupporttolOnesupporttolTwo lOnesupportto lFivesupportstol l Support l CEB-Cl-21. 89. l CEB-C I-21. 89.
lsupportsto lCEB-CI-21.89, lCEB-CI-21.89, l
l Evaluations l Negligible lincreaseonly lCEB-CI-21.89.lincreaseonly I three of five l
l lincreaseto l0.1lbs lloadin-l0.6%onthis lloadsdecreased,j l
lallsupports l negligible l crease <
l support. Not ltwoothers l
l l
l l2.2%
lsignificant.
l increased l
l l
l l negligible l
l<1%
l l
l l
I I
l l
TABLE D4.2-3-2A
- Due to the removal of additional conservatism in the ori inal design basis S
floor response spectra in the low frequency region.
l DNE4 - 2859Q NTB - 2/28/88 e
,..,5
. l Systemsl l
l l
l l
l l
1 I
I l
1 lConponent l N2-3-10A, llA l N2-31-05R l N2-64-3A lN2-67-3R lN2-67-10R l
l lSCV-A8 lSCV-AB lSCV-ICS lSCV-ICS lSCV-ICS l
l 1
1 I
I I
l l Applicable lSCV-730.5 lSCV-715.29 lSCV-772.16 lSCV-759.59no lSCV-701.5 l
l Spectra /
lShieldb1dg llCS-112.0-721.9] AB-748.5 l change lICS692-712 l
l Elevation lAB-688.5-732.5l l
l1C5-746 l
l l
l 1
l l
I l
Pipe Stress Bending stress Bending stress Bendingstress*lBendingstress Max bending stress showed neglig.
showed neglig.
decreased < 1% l decreased
- decreased
- l l increase <3% l increase <1*.
l l
l l
l l(284 PSI) l l
l l
l 1
l l
l 1
l l
l l
I I
I I
l l Penetration l2 Penetrations l Max force iner l Load increase lSlightload lMinorincreaseinl l Loads
\\Maxincrease lof3Lbs, Max lNeglig,Less l decrease
- lMx&Mz(1.9Ft-l l
15.8%
lMcrncet of 2 Ft-lThan.1 lb &
l lLbs)Overall l
l l
lLbsNeglig l1Ft-Lbs l
l decrease
- l l
l l
l l
I l.
l Nozzle l Negligible lNone lNone lNone lNone l
l Loads lincr.innozzlel l
l l
l l
l loads l
l l
l l
l l
l l
l I
l l
1 I
i i
l l
l Valve l Numerous valves l5 Valves-accel l Increase << 1% lisolationvalve l7Valvesneglig. l l Accelerations lMinorincreasesl<0.5G l
l Supported, N/A lince=6%< allow.l l
l l increase, l
linhorir, vert l
l l
l lNeglig, largest l l change l
l l
l 1.087 G l
inegli < ".
l l
l Support lFoursupports lNosupportstolOnesupportto lOnesupportto l One support to l
l Evaluations ltoCCB-CI-21.89lCEB-CI-21.89 lCEB-CI-21.89, lCEB-CI-21.89.
lCEB-CI-21.89.
l l
l0neinerof lLoadincrease ]Nochangein lAllloads lIncreaseinloadl l
l5.6%butstilll<10".small l load for interim l decreased lforCEB-CI-21.89l l
l meets lloadsoverall l support.
lslightly
] support <5".
l l
lCEB-CI-21.89 l
lOtherchanges l
l Critical l
l l1.C.=0.48 l
l negligible.
l lcomponentis l
l l<l.0onbase-l l
l lanchorw/1.C.= l l
l plate.
l l
l l0.58<l.0 l
l lOnevert l
l l
lOthersupport l
l lsnubbernot l
l l
lloadincreases l
l laffected, l
l l
lalsonegligible l
)
l lOne 1.6". Incr. l l
l l
l l
l lneglig,oneincrl l
l l
l l
l lless5".still l l
l l
l l
lrreets l
l l
l l
l l
lCEB-CI-21.89 l
l l
l l
1 i
f I
l I
1 l
l TABLE D4.2-3-2.B
- Due to the removal of additional conservatism in the original design basis floor response spectra in the low fecquency region.
DNE4 - 2859Q NTB - 2/28/88 4