ML18026B135
| ML18026B135 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 07/26/1984 |
| From: | Vassallo D Office of Nuclear Reactor Regulation |
| To: | Parris H TENNESSEE VALLEY AUTHORITY |
| References | |
| NUDOCS 8408140026 | |
| Download: ML18026B135 (17) | |
Text
Docket No. 50-259/260/296 Mr. Mugh G. Parris Manager of Power Tennessee Valley Authority 500 A Chestnut Street, Tower II Chattanooga, Tennessee 37401
Dear Mr. Parris:
DISTRIBUTION NRC PDR Local PDR ORB¹ Rdg DEisenhut OELD EJordan JNGrace DClark WLong SNorris ACRS(10)
Gray File
SUBJECT:
MARK I CONTAINMENT LONG TERM PROGRAM PLANT UNIQUE ANALYSIS REPORT LOADS EVALUATION Re:
Browns Ferry Nuclear Plant, Unit Nos.
1, 2 and 3
The NRC staff and its consultants Brookhaven National Laboratory (BNL) and Franklin Research Center (FRC) are reviewing the loads and structural aspects of your plant unique analysis report.
As a result of our review to date we have prepared the enclosed requests for additional information.
We recommend that a meeting with the staff and BNL and FRC be held the week of September 10, 1984 to discuss this request prior to your submittal of a formal response to avoid any misunderstanding and to minimize the need for another round of questions.
If this meeting date is not acceptable please notify your project manager within seven days of receipt of this letter as to the date you can, meet.
This request for information was approved by the Office of Management and Budget under clearance number 3150-0091 which expires October 31, 1985.
i
Enclosure:
As Stated cc w/enclosure See next page Original signed by; Domenic B. Vassallo, Chief Operating Reactors Branch ¹2 Division of Licensing DL'B¹2 DL:ORB¹ D '0
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Mr. Hugh G. Parris Tennessee Valley Authority Browns. Ferry Nuclear Plant, Units 1, 2 and 3
CC H. S. Sanger, Jr., Esquire General Counsel Tennessee Valley Authority 400 Commerce Avenue E llB 330 Knoxville, Tennessee 37902 Mr.
Ron Rogers Tennessee Valley Authority 400 Chestnut Street, Tower II Chattanooga, Tennessee 37401 Mr. Charles R. Christopher
- Chairman, Limestone County Commission Post'ffice Box 188
- Athens, Alabama 35611 Ira L. Myers, M. D.
State Health Officer State Department of Public Health State Office Building Montgomery, Alabama 36130 Mr. H. N. Culver 249A HBD 400 Commerce Avenue "Tennessee Valley Authority Knoxville, Tennessee 37902 U. S.
Environmental Protection Agency Region IV Office Regional Radiation Representative 345 Courtland Street, N.
W.
Atlanta, Georgia 30308 Resident Inspector U. S.
Nuclear Regulatory Commission Route 2, Box 311
- Athens, Alabama 35611 Mr. Donald L. Williams, Jr.
Tennessee Valley Authority 400 West Sum'mit Hill'rive, W10885 Knoxville, Tennessee 37902 George Jones Tennessee Valley Authority Post Office Box 2000
- Decatur, Alabama 35602 Mr. Oliver Havens U. S; Nuclear Regulatory Commission Reactor Training Center Osborne Office Center, Suite 200 Chattanooga, Tennessee 37411 James P. O'Reilly Regional Administrator Region II Office U. S. Nuclear Regulatory Commission 101 Marietta Street, Suite 3100 Atlanta, Georgia 30303
REQUEST FOR ADDITIONAL INFORMATION BROMNS FERRY NUCLEAR PLANT, UNIT NOS.
1, 2 AND 3 MARK I CONTAINMENT LONG TERM PROGRAM -
PUAR DOCKET NOS. 50-259/260/296
ITEM I:
According to Section 4.2.5 of the
- PUAR, BEN used the loads defined bf the PULD and the LDR Sec.
4.3.2 for pressure loads on the torus.
How-
- ever, BFN applied a much analler margin on the LDR load than stipu-lated in NUREG-0661< p. AH ~
The BFN margin of 6.5% on the LDR upload is justified in the BFN PUAR on the basis that the 15% margin reccoanended on p.
39 of NUREG-0661 is unnecessary because the EPRI 1/12-scale model had the BFN geanetry, and that the Acceptance Criteria margin of 21.5% should therefore be reduced ky 15% to yield 6.5%.
This does not meet the intent of the AC.
The 15% margin of NUREG-0661 was imposed for several reasons (see pp. 36-38 of NUREG-0661),
the gecmetry being only one of the con-cerns.
Consequently, a full justification for the reduction of the margin fran 21.5% to 6.5% is needed, or the ability of the torus to withstand a 15% load increase must be demonstrated.
ITEN 2:
What margin was applied on the LDR download?
Is the downloa'd specifi-cation consistent with Sec.
2.3 of the Acceptance Criteria?
ITEN 3:
For what structures would the load exceed acceptable levels if the torus pressure loads were made consistent with NUKM-0661?
By how
- much, and for what load ccmbinations?
ITEN 4:
Was the vent header impact load definition of p. 6-17 of the PUAR in accordance with Sec.
2.10.1 of NUREG-0661'? If not, explain the dif-ferences and provide estimates showing that sufficient margin exists to accmmodate the NUREG load.
ITEN 5:
Were the IOCA jet and tubble drag loads for BEN evaluated in accor-dance with the LDR and NUREG-0661?
ITEN 6:
For analyzing structures affected by CO loads, the LDR and NUREG-0661 prescribe absolute supination of the m load harmonics at 1 Hz inter-vals frcm 1 to 50 Hz.
BFN used an alternate approach where:
(i) forcing frequencies above 31 Hz were neglected and (ii) four particular load harmonics (the ones at 4-5, 5-6, 10-11, and 15-16 Hz) were added absolutely and added to the SRSS of the re-maining 26.
Justify the neglect of forcing frequencies alive 31 Hz for (a) torus shell loads and
( b) suhnerged structure drag loads.
(Arguments about small torus response do not apply for drag loads.)
Why were CO drag loads (p. 4-4) analyzed for 1-31 Hz only, but post-chug drag loads (p. 4-5) for 1-50 Hz?
ITEM 7:
The approach of GE/NEDE 24840 which is itself a departure frcm the LDR calls for taking the sun of the four harmonics which produce the highest structural response, and adding them to the SRSS of the re-maining harmonics.
Were the forcing functions at 4-5, 5-6, 10-11, and ITEN 8:
15-16 Hz the ones which produced the highest structural response for both torus shell and all drag loads?
In the work done by SMA (Refer-ences 19 and 42 of the BFN PUAR), the absolute supination of the four highest harmonics had nothing to do with phase relationships, but was an artifice used to arrive at an 84% non-exceedance probability (NEP).
Based on the discussion in the PUAR, BFN's procedure does not guarantee an NEP of 84%.
Justify BFN's departure frcm the reconmended procedure and/or demonstrate structural margins which would adequately cover increases in the CO loads.
Was Alternate 4 of the CD baseline rigid wall pressure spectrun applied to BFN?
Were pre-chug loads applied to BFN according to the LDR and NUREG-0661 specifications regarding amplitude, circumferential and vertical dis-tribution, and cycle duration?
If not, provide quantitative justifi-cation.
ITEM 9:
For post-chug
- loads, were the harmonic forcing functions used in the 1-30 Hz range the ones specified in the LDR, and were they applied in the manner prescribed in the LDR? If not, justify departures.
ITEM 10:
The finite-element model of Fig. 6-7 shows amputated downccmers.
How were the CO and CH loads applied to these amputated downccmers?
ITEM 11:
Were the CO loads applied to the downccmers in accordance with the LDR and NUREG-0661?
Were the eight load cases of Sec. 4.4.3.2 of the LDR analyzed for all relevant vent system parts (including main vent/vent header intersection, drywell/main vent interaction, downcaner/vent header intersection, etc.)?
The PUAR explicitly mentions considering different load cases only for the downccmer/tiebar intersection, and in that case refers only to four load cases rather than the eight of the LDR (Sec. 6.7.1.2.1).
Why is 2.5% damping justified for BFN for CO lateral load analysis?
Note that Table 6-10 shows no margin for the downccmer/vent header in-tersection in load canbination 27 which involves CO.
ITEM 12:
Were the chugging loads applied to the downccmers in accordance with the LDR and NUREG-0661?
Were the multivent chugging loads accounted for on all vent system parts in accordance with the LDR and NUREG-0661?
Note that according to Table 6-10, load ccmbination 15, which involves CH, has relatively little margin.
ITEM 13:
What hydrodynamic load definition was used for the vent pipe drain re-ferred to on p. 6-10 and shown on Fig. 6-8?
ITEM 14:
Ccmbining individual SRV shell pressures by SRSS to obtain multiple valve shell pressures is an exception to the AC.
Justify this procedure for BFN.
ITEM 15:
Clarify the statement that the torus was analyzed quasi-statically for SRV hydrodynamic shell pressures.
Where does g(t), i.e.,
the wave form of the pressure history, in the expression on p. 5-13 of the PUAR cane fran?
Are pressures applied statically as stated on p. 5-12 or is there a time variation as implied by the expression on p. 5-13?
ITEM 16:
Provide the following additional information regarding the in-plant SRV tests conducted at BFN and the SRV design loads extrapolated from the tests:
1.0 Description of the tested Quencher Device 1.1 Drawings showing details of the quencher gecmetry
- plan, elevation, arm length, arm diameter, hole arrangement, spacing/
size, etc.
1.2 Location of quencher device relative to suppression pool boundaries and suppression pool surface.
1.3 Any difference between the.tested quencher configuration and the Monticello version (as described in GE NEDE-24542-P) highlighted and quantified.
2.0 A description of the loads observed during testing 2.1 Peak overpressure (POP) and underpressure (PUP) recorded on the torus shell during each relevant SRV actuation.
2.2 A measure of the frequency content of each pressure signature.
3.0 A description of the test conditions 3.1 Gecnmtry of the tested SRVDL (diameter, length, free volume, and routing belch pool surface).
3.2 Gecmetry of any SRVDLs in the plant that differ significantly from the tested SRVDL.
3.3 SRV steam flow rate (MS), pool temperature (TPL), pipe tem-perature (TP), water leg length (LW) and pressure differential (hP), if any, for each test.
3.4 Minimum hP permitted ty NRC Technical Specification and corres-ponding LW for all SRVDLs.
4.0 A description of the design conditions for each load case used for design 4.1 Gecmetry of all SRVDLs involved and their azimuthal location in the torus.
4.2 TP, TPL, MS, W and LW for all SRVDLs involved.
5.0 A description of the design loads for each load case 5.1 Normalized pressure signature.
5.2 Single valve POP/PUP values.
5.3 Spatial attenuation of the POP/PUP values (if this differs fran the LDR methodology, sufficient additional torus shell pressure data must be supplied to justify such deviation).
5.4 Frequency range considered.
I ITEM 17:
Elaborate on the methodology used to account for fluid-structure in-teraction effects during CO and chugging drag loads in BFN, which is mentioned in Sec.
4.4.9 of the PUAR.
ITEM 18:
What is the vertical location of the suppression pool temperature sen-sors in relation to the SRV T/Quencher centerline?
ITEM 19:
Were there any exceptions to the AC for the hydrodynamic loads applied for analysis of the Torus Attached Piping? If so, elaborate.
ITEM 20:
In the calculation of various drag loads for BFN, the ccmputer codes e
- LOCAFOR, CGNDFOR, TQFORBF and TQFOR03 were used.
lX) the algorithms of these codes follow approved AC procedures?
State any exceptions and justify them?
ITEM 21:
Are there any differences between Browns Ferry Units 1, 2 and 3 which were significant enough to warrant separate analyses for any unit? If so, state the differences and the analyses used.
APPENDIX B ADDITIONAL INFORMATION REQUIRED Franklin Research Center
'A Division of The Franklin Institute The Senlamrn Frankirn Parkway. Phila., Pa. l9l03 (2 l5) 4 '8 l 000
TER-C5506-323 RE UEST FOR INFORMATION Item 1:
Provide a more detailed description of the vent systera analysis regarding downcomer lateral loads (Section 4.4.5 [5]).
Item 2:
provide the physical details of the seisraic lugs that restrain the torus against horizontal seismic motion yet allow thermal growth.
Item 3:
Indicate how the ring girders were analyzed for loads from attached internal structures.
Any dynamic load factors that may have been used in the analysis must be provided and justified.
Item 4:
With respect to the 22-1/2 torus model mentioned in Section 5.4.1.1 of the PUA report [5], the boundary conditions are based on the assumption that all loads are applied equally to each of the 16 segments.
- However, the safety relief valve and chugging loads are asymmeterical.
Justify the use of' 22-1/2'odel to evaluate the torus for SRV and chugging instead of the 180 model required by the criteria [1].
Item 5:
Figure 5-6 in the PUA report [5]; which depicts the 180'odel of the torus, shows only the lower half of the torus shell.
Indicate whether the model includes the torus supports.
Item 6:
Since NRC Regulatory Guide 1.61
[4] deals with damping values for the seismic design of structures, explain how this Regulatory Guide validates the use of 4% damping for the 0.0 hP pool swell analysis of the torus (Section 5.4.2.7
[5]).
Item 7:
With respect to Section 5.4.2.11 of the PUA report [5],'provide the technical basis and justification for considering the forcing functions from 0 to 30 Hz instead of the full 0 to 50 Hz for post-chug analysis of the torus.
Item 8:
Items 2 and 3 in Section 5.4.2.11 of the PUA report [5] suggest that the pre-chug load bounds the post-chug load in the analysis of the torus; however, Item 5 in Section 5.4.2.11 indicates a higher surface stress for post-chug.
Explain this apparent inconsistency and indicate whether pre-chug or post-chug was considered in the controlling load combinations for the torus.
Item 9:
With respect to the fatigue analysis of the torus presented in Section 5.4.6 of the PUA report [5], specify the elasticity methods used to calculate stress intensification factors at the penetrations.
IIIl Franklin Research Center A Msion d 'The F(anon Institute
TER-C5506-323 Provide and justify the bounding technique used to determine the controlling load cases presented in the PUA report [5] in the following Sections:
5.5.1, page 5-21 6.3.2 (and Table 6-5), page 6-6 6.4.2 (and Table 6-7),
page 6-7 6.5.2 (and Table 6-9), page 6-8 6.7.2 (and Table 6-12),
page 6-12 6.8.2 (and Tables 6-15 and 6-16),
page 6-14 6.9.2 (and Tables 6-17, 6-18, and 6-19),
page 6-15 7.3.1 (and Table 7-1), page 7-7 7.4.1 (and Tables 7-2 to 7-4),
page 7-12 8.2.22 (and Table 8'-2), page 8-3
- 9. 1, page 9-2 9.2, page 9-2 Provide the stress results from the analysis of the torus shell and supports.
Regarding the analysis of the main vent/drywell intersection, clarify whether the seismic and thermal response of the drywell was considered (Sections 6.2. l. 2.7 and 6. 2.1. 2.9
[5] ).
Provide a summary of the analysis of the vacuum breaker valves; indicate whether they are considered Class 2 components as, required by the criteria [1].
The PUA report
[5] indicates that the calculated stress values at the following locations are very close to the respective allowables:
o downcomer/vent header intersection (Section 6.5.4.1) o downcomer/tiebar intersection (Section 6.7.4. 1)
Indicate conservatisms in the analysis to show that these calculated values would not be exceeded if a different analytical aproach were to be used.
Stress intensification factors for the miter bends in the vent system are not found in Table 6-17 as stated in Section 6.9.1 of the PUA report
[5].
Provide these factors.
Regarding the torus bellows analysis in Section 6.10. 1.1 of the PUA report [5], provide the method and technical basis for calculating the spring values that represent the bellows flexibility in the computer models of the vent system (Figures 6-2 and 6-3 [5]).
Provide and justify the approach for the fatigue evaluation of the bellows mentioned in Section 6.10.3 of the PUA report [5].
TER-C5506-323 Item 18:
According to Section 7.3.3.1 of the PUA report [5], the safety relief valve line penetration of the main vent was modeled using cylindrical shell flexibilitycharacteristics.
Indicate the method for determining these characteristics.
Item 19:
Provide the technical basis for obtaining the stress intensification factors used in the analysis of the safety relief valve discharge piping system (Sections 7.3.3.1 and 7.4.3.1 [5]).
Itera 20:
provide the stress results from the wetwell and drywell safety relief valve discharge piping analysis (Sections 7.3.4.1 and 7.4.4.1
[5])-
Item 21:
Provide and justify the allowable safety relief valve nozzle loads which were referred to in Section 7.3.4.2 of the PUA report [5].
Item 22:
With respect to Section 7.4.3.2.1 of the PUA report [5], provide and justify all dynamic amplification factors used in the calculation of safety relief valve discharge-.induced fluid drag forces on the safety relief valve system.
Item 23:
With respect to Section 8.2.3.3 of the PUA report [5], provide and justify the reasons for not considering the contributions of higher modes above 20 Hz for seismic analysis of torus-attached piping systems.
Item 24:
With respect to Section 8.2.5.2 of the PUA report [5], provide justification for considering branch lines having peak spectral accelerations below 5.0 g at the point of attachment to the'process line to be qualified without further evaluation.
Item 25:
With respect to Section 8.2.5.5 of the PUA report [5], provide justification for considering the valves with accelerations less than 3-g horizontal and 2-g vertical and having no operator supports to be qualified without further evaluation.
Item 26:
provide a schedule for the completion of pipe support modifications for Units 2 and 3.
~ 'U Franklin Research Center tl[IA
uIlt'llFranklin Research Center A Dieqion oi The Franklin institute 20th and Race Streets. Phila.. Pa. 19103 (21S) 4 000 t-RC.='cnc: No. C55tto FRC Assignc-,. n:.; /2.
FRCTask No. wZ %
Plant Name <+p+hJQ ~~ y Table1. Structural Loading (from Reference3)
Structures Other Wetwelt Interior Structures Loads (0
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o O
to 0
- 1. Containment Pressure and Temperature
- 2. Vent System Thrust Loads
- 3. Pool Swell 3.1 Torus Net Vertical Loads 3.2 Torus Shell Pressure Histories 3.3 Vent System impact and Drag 3.4 Impact and Drag on Other Structures 3.5 Froth Impingement 3.6 Pool Fallback 3.7 LOCAJet 3.8 LOCA Bubble Drag
- 4. Condensatlon Oscillation 4.1 Torus Shell Loads 4.2 Load on Submerged Structures 4.3 Lateral Loads on Downcomers 4.4 Vent System Loads
- 5. Chugging 5.1 Torus Shell Loads 5.2 Loads on Submerged Structures 5.3 Lateral Loads on Downcomers 5.4 Vent System Loads
- 6. quencher Loads 6.1 Discharge Line Clearing 6.2 Torus Shell Pressures 6.4 Jet Loads on Submerged Structures 6.5 AirBubble Drag 6.6 Thrust Loads on T-Quencher Arms 6.7 S/RVDI EnvironmentalTemperature
- 7. Ramshead Loads 7.1 Discharge Line Clearing 7.2 Torus Shell Pressures 7.4 Jet Loads on Submerged Structures 7.5 AirBubble Drag 7.6 S/RVDL Environmental Temperature X
X X
X X
X X
X X
X X
X X
'X X
X X
X X
X X
X X
X X
X X
X X
X X
X X
X X
X
'X X
X X
X X
X X
X X
QX QX g
g Loads required by NUREG4661[al Qx Not applicable.
TER-C5506-323 REFERENCES FOR APPENDIX B 1.
NEDO-24583-1 "Mark I Containment Prograra Structural Acceptance Criteria Plant Unique Analysis Application Guide" General Electric Co.,
San Jose, CA October 1979 NUREG-0661 "Safety Evaluation Report, Mark I Containment Long-Term Program Resolution of Generic Technical Activity A-7" Office of Nuclear Reactor Regulation July 1980 3.
NED0-21888, Revision 2
"Mark I Containment Program Load Definition Report" General Electric Company, San Jose, CA November 1981 4.
NRC "Damping Values for Seismic Design of Nuclear Power Plants" Regulatory Guide 1.61 October 1973 5.
Tennessee Valley Authority Browns Ferry Nuclear Plant Units 1, 2, and 3
Plant Unique Analysis Report CEB-83-34, Revision 0
December 21, 1983 tj00 Franklin Research Center A Onnuon ot The Franklin InsuMe
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