ML20114D279
| ML20114D279 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 01/28/1985 |
| From: | Dale L MISSISSIPPI POWER & LIGHT CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| AECM-85-0028, AECM-85-28, TAC-49995, TAC-60119, NUDOCS 8501310167 | |
| Download: ML20114D279 (37) | |
Text
..
MISSISSIPPI POWER & LIGHT COMPANY ^
Helping Build Mississippi P. O . B OX 1640, J AC K S O N. MIS SIS SIP PI 3 9 2 05 January 28, 1985 NUCLE AR LICENSING & $AFETY DEPARTMENT U. S. Nuclear Regulatory Commission ,
Office of Nuclear Reactor Regulation Washington, D. C. 20555 Attention: Mr. Hcrold R. Denton, Director
Dear Mr. Denton:
SUBJ1:CT: Grand Gulf Nuclear Station Units 1 and 2 Docket Nos. 50-416 and 50-417 License No. NPT-29 File: 727/L-334.0/L-860.0 Soil Structure Interaction -
NRC Questions Regarding Standby Service Water Cooling Tower Basin AECM-85/0028 By letter to Mississippi Power & Light (MP&L) dated October 29, 1984 (MAEC-84/0392), the NRC staff requested additional information on thu seismic analysis performed for the deeply embedded Grand Gulf Nuclear Station (GGNS)
Standby Service Water Cooling Tower Basin (SSWCTB). Specifically, this letter indicates that MP&L did not state that the seismic analysis had been performed according to the agreement reached during the March 16, 1983 MP&L/NRC soil-structure interaction (SSI) meeting and requests further details on the v =
principles and techniques used in this analysis.
As detailed in MP&L's response to this request for additional information (attached), the floor response spectra (FRS) obtcined from the Finite Element Methodology (FEM) were first compared to the FRS generated from the Elastic IIalf Space (EHS) methodology, in response to an NRC Structural Engineering Branch (SEB) request (reference FSAR Question 130.25). The enveloped spectra from these two methods were used for the review of component design and equipment qualification. However, the EHS analysis was considered unaccept-able by the NRC since it incorporated a forty (40) percent reduction factor to account for embedment effects. To resolve NRC concerns regarding the soil-structure interaction issue, a meeting was held on March 16, 1983.
During this meeting, MP&L presented several alternative EHS approaches which would account for embedment. After indicating that these al:ernative approaches were unfamiliar and could require substantial review, representatives of the NRC SEB suggested that MP&L consider use of a Beredugo and Novak methodology using Regulatory Guide 1.60 to define the seismic input motion. However, MP&L decided not to take advantage of this option and instead utilized the EHS methodology based on the Bechtel Power Corporation topical report BC-TOP-4 with the refinement discusscd in the attachment but -
without incorporating the 40 percent peak reduction proposed earlier.
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_ _ _ _ _ _ _ _ . . . . A
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AECM-85/0028 MISSISSIPPI POWER Q LIGHT COMPANY P888 2 Since it was the 40 percent peak reduction that the NRC indicated to be unacceptable [ reference letter from A. Schwencer (NRC) to J. P. McGaughy
-(MP&L), dated January 12, 1983), MP&L reasoned that this approach would expedite resolution of this issue by the NRC [ reference Operating License
. Condition 2.C.(6)]. Therefore, an engineering assessment was initiated to determine the impact on the SSWCTB component design and equipment qualifica-tion'using the envelope of the FRS curves generated from the FEM Model and the EHS model with no reduction factor applied to the EHS curves. This assessment involved the'use of the Grand Gulf site-specific free field surface ground acceleration time history. MP&L considers this time history to be the design basis for the plant .and furthermore considered it to be acceptable to the NRC as discussed in Sections 2.6.2.4 and 3.7.1 of the GGNS Safety Evaluation Report '(SER) and lin Section 3.7.1- of Supplement.1 to that SER.
MP&L's intended approach to resolving this issue was communicated to you in AECM-83/0654, dated October 14,.1983, as was our intent to complete all required modifications prior to startup.following the first refueling outage, consistent with Operating License Condition 2.C.(6). The attached responses to the questions in the NRC staff's October 29, 1984 letter are, therefore.
based on our EMS without 40 percent peak reduction and FEM envelope analyses,
~
which MP&L considers to be conservative and consistent with the CGNS established licensing basis, 'as discussed in FSAR Section- 3.7.2 and the above referenced SER sections.
If you have any further questions, please contact this office.
Yours truly, V . F. Dale Director MLC/JGC:rw Attachment cc: Mr. J. B. Richard (w/a)
Mr. R. B. McGehee (w/a)
Mr. N. S. Reynolds (w/a)
Mr.'G. B. Taylor (w/o).
Mrc Richard C. DeYoung, Director (w/a)
Office of Inspection ~& Enforcement
'U. S. Nuclear Regulatory Commission Washington, D.'C. 20555 Mr. ' J. . P. O'Reilly, Regional Administrator (w/a)
- U.S. Nuclear Regulatory Commission Region II' 101.Marietta St...N.W., Suite 2900
' Atlanta, Georgia 30323
GRAND GULF SEISMIC ANALYSIS OF THE STANDBY SERVICE WATER COOLING TOWER BASIN INTRODUCTION Pursuant to 'a meeting with the NRC on March 16, 1983 on the subject of soil-structure interaction (SSI), Mississippi Power & Light (MP&L) sub-mitted to the NRC (via AECM-83/0654, dated Oct. 14, 1983) an engi-neering assessment of the impact of using enveloped floor response spectra (FRS), 'from both the elastic half-space and the finite element methodologies, on the seismic design adequacy of all structural supports, equipment, pipings, and components in the standby service water cooling tower basin (SSWCTB). Based on this evaluation, MP&L committed to completing any required modifications prior to ctart-up following the first refueling outage.
In reviewing the above submittal, the NRC requested, in a letter dated October 29,1984 (Reference 1), additional information on the Grand Gulf Seismic analysis of the' SSWCTB. The information requested in Refe-rence 1 is provided on the following pages.
1
~ - ,
QUESTION 1 FROM THE NRC IN REFERENCE 1
- 1. Description of the method used in the analysis, including basis assumptions, variation of key analysis parameters, basis for cal-culating the soil spring constants used to simulate the embedment effects as well as description of the seismic input and its compliance with the provisions of the Regulatory Guide 1.60.
ANSWER TO QUESTION 1 FROM THE NRC IN REFERENCE 1 The SSWCTB is a deeply embedded structure, as shown in FSAR (Refe-rence 2) Figure 3.7-24 (see Figure 1). The structure is virtually
. identical in the north-south (N-S) and east-west (E-W) directions.
To account for the soil-structure interaction (SSI), the seismic design loads -.(SSE and OBE) for the SSWCTB structure were determined by using the ' elastic half-space (lumped parameter) method provided in BC-TOP-4 (Reference 3). The configurations of the SSWCTB seismic analytical models = for the vertical and horizontal directions corresponding to.this elastic half-space (EHS) method are as shown in Figures 2a and 2b (excerpted from the FSAR), respectively. In the development of these seismic loads, the following conservatisms exist:
- a. The embedment effect is neglected.
- b. . The free field surface ground acceleration time history was applied at the foundation level (base mat) of the - SSWCTB.
The Grand Gulf site-specific ground acceleration time history -(for.de-sign), which has been accepted by the NRC staff as indicated in Sec- -
[~ tion 2.6.2.4 of the~ Safety Evaluation ' Report (SER) (Reference 14) and ;
in .Section 3.7.1 of Supplement 1 to the SER (Reference 4), was used.
h Per NRC ' staff request, -FRS for the component design and equipment qualification for the SSWCTB were performed by using the finite element approach : to . account for ' SSI. Later,' this approach became one.of the requirements in Section 3.7.2' of the standard review ple.n (SRP) (Ref-erence 5). In this analysis, the . Grand ~ Gulf ground acceleration time history was used. The SSWCTB SSI J seismic analysis, based on the finite element approach, was performed using c the computer programs SHAKE and LUSH, as described in Section;3.7.2.4 in the FSAR. The~
1 seismic FRS generated by the' SHAKE and LUSH computer programs were .
used for component. design and equipment. qualification;for the SSWCTB.
Later, additional finite element seismic SSI analysis for the SSWCTB was
. performed ' as described in AECM-82/316 (Reference 6). The finite ele-ment seismic SSI model used in" the -additional- analysis is .as shown in-Figure 3. This additional analysis ~ concentrated on enhancements s regarding:
- a. -The selection of size and shape of certain elements representing-the soil-x .
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.b. ' The soil property' definition 7
2
- . . . . . . . . . . ._ _ _ - . _ - . _ _ l
a.= . = = = .= = = w.- - -
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i c. Properties used in the plane strain elements representing the structure The. additional analysis utilized the more current standard computer
, program FLUSH (Fast LUSH), which had replaced the SHAKE and LUSH
. programs. , Although FLUSH has the option to provide a viscous boundary that represents radiation damping perpendicular to the plane of the model, this option was conservatively not employed. Results of the 4
FLUSH analysis generally provided FRS curves with lower peaks than the p' _ original SHAKE and . LUSH analysis FRS curves. The final qualification evaluation of the components and equipment in the SSWCTB was based on the enveloped FRS from the SHAKE and LUSH analysis and the FLUSH
, analysis. - The . result of this evaluation shows that all components and equipment in the SSWCTB remained seismically qualified.
'NRC Question No.130.25 (FSAR, Volume 24, page Q&R 3.7-24) required the FRS' obtained from the finite element approach to be compared with
- results obtained by the EHS (lumped parameter) approach. In response to that question, additional FRS curves based on the EHS approach were generated and reported in Reference 9. For this FRS generation, the
, analytical seismic SSI model of the SSWCTB was based on the previously described s EHS idealization with lumped soil parameters to simulate the
. elastic half-space (Figures 2a and 2b). In addition to defining the soil parameters per BC-TOP-4 (Reference 3) as outlined before, the 'new EHS analysis also considered the frequency shift that accompanies the effect -
of embedment by modifying the soll parameters based on a method presented in. . Reference .7. .This enhanced EHS _ analysis, hereafter designated as the " refined" EHS analysis, was determined to be .more -
conservative 'than the EHS. analysis ignoring the ' effects ' of ~ embedment.
' This is because spectra curves generated from the refined EHS analysis
- envelop the. respective 1 spectra curves obtained from the original EHS
. analysis.
In this refined EHS analysis, the Grand Gulf licensed free field surface ground acceleration , time history was applied ' at the foundation" level (Mass Point 1 in Figures 2a and 2b) of the SSWCTB. The seismic design ~
loads ~ obtained from the^ refined ' EHS analysis are . all l lower -than the
._ seismic: design-loads obtained from the original EHS analysis, which was.
U used . for the ' design of . the SSWCTB structure. _ Hence, the' SSWCTB h' 1 structural ~ design is' also adequate with respect to the . refined - EHS.
analysis.
L The peaks of the lateral SSWCTB FRS' curves from ~ the (refined) EHS
' model are much higher than the peaks of the SSWCTB FRS curves from
, . ( the 1 S. HAKE =and : LUSH, and ' FLUSH ! finite element _ seismic models. As stated in Reference 9; the large amount by which the EHS peak exceeded-
.the FLUSH peak'was attributed to the (refined) seismic EHS model being.
unable : ~ to adequately account for ' ithe 'embedment . effect. As a
- consequence, a' parametric study on the effect of embedment was per-formed for the SSWCTB by .using the finite element -approach. This parametric study indicated 'an approximately 40 to 70 percent. reduction in peaksEof the .FRS curves from the nonembedded seismic finite element .
- model : to ; the fembedded finite 1 alement model, which, more importantly, s , 3
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g . . - . _ . _ .
l l
agreed with the physical test data reported in Reference 10. Hence, a correction factor of 40 percent reduction (Reference 9) was applied to the peaks of the SSWCTB FRS curves from the (refined) EHS analysis.
This reduction resulted in good agreement between the FRS curves from the (refined) EHS seismic model and the enveloped FRS curves from the SHAKE and LUSH, and FLUSH finite element seismic models. The conclusion w5s that the FRS curves from the SHAKE and LUSH, and FLUSH finite element models are adequate and acceptable for the component design and equipment qualification in the SSWCTB.
The NRC did not find (Reference 11) the application of a 40 percent re-duction factor to the peaks of the FRS curves imposed on the EHS approach to be acceptable. Subsequently, a meeting was held with the NRC in March 1983 to discuss an acceptable alternate approach for responding to Reference 11. As' a result of this meeting, the 40 percent reduction of the peaks in the FRS curves generated by the EHS approach would not be utilized, and an optional method to account for ,
the embedment effect (based on EHS' approach) similar to the one developed by Beredugo and Novak in Reference 12 might be considered.
Although the NRC staff indicated they were not familiar with specific details of that methodology, they had no objection to MP&L using this proposed method (Reference 12). However, if this proposed method
- were used, the NRC staff requested that Regulatory Guide 1.60 (Refer-ence 13) should also be used -(although not a licensing commitment) to define the input motion.
However, MP&L decided not to take advantage of this option and, instead, utilized' an approach with which the NRC was familiar; specif-ically, 'the EHS methodology based on BC-TOP-4 with the refinement dis-cussed 'above : but without incorporating the -40 percent peak reduction proposed earlier. Since it -Was the 40 percent peak reduction that the NRC indicated to be unacceptable (Reference 11), MP&L reasoned l that this approach would expedite resolution of this issue by the NRC (refer-ence Operating License Condition 2.c.(6)). Therefore, an engineering assessment was initiated to determine the impact on the SSWCTB compon-ent design and equipment qualification. using the envelope of the FRS curves generated from (1) the (refined) EHS seismic model (derived by
'the method in References ;7 and 8) as described earlier, with no ' peak reduction -factor' applied to the resulting FRS curves, and (2) the
- s SHAKE and LUSH, and FLUSH finite element seismic models. As re-
. ported .in Reference 9, this - assessment indicated that 'except for the
- modification of nine existing pipe supports and the addition of. four new pipe supports,. no other hardware modifications were identified as being necessary. Consistent with Operating License Condition 2.c.(6),
all required modifications are to be completed prior to -start-up fol-
-lowing the first refueling outage.
-In conclusioni
- a. The licensed Grand' Gulf site-specific free field surface ground acceleration time history was - used as input for all the seismic analyses of the SSWCTB. This ground acceleration time history has been : accepted. -by the NRC staff as- Indicated in Sec-
. tion 2.6.2.4' of the SER (Reference 14) and in Section 3.7.1 of 4
~
. Supplement 1 of the SER (Reference 4). -Regulatory Guide 1.60 (Reference 13) design (ground) spectrum curves were not used to define the seismic input motion, since the method to account for the embedment effect similar to the one developed by Beredugo and Novak (Reference 12) was never employed.
- b. In 'all seismic analyses of the SSWCTB based on the ' EHS approach the . licensed Grand Gulf site-specific free field surface ground acceleration time history was . conservatively applied at the foundation level- (Mass Point 1 in Figures 2a and 2b) without any deconvolution considerations due to' the embedment soll. .However, because of very deep embedment, in all seismic analyses of the SSWCTS based on the finite element approach, the licensed Grand Gulf site-specific free field surface ground acceleration time history was appropriately applied at top of the soil elements (approximately at grade level) in the deconvolution of the free field motion.
- c. The seismic design loads used . for the design of the SSWCTB structure were taken from the. original seismic model based on the EHS approach, which enveloped the seismic design loads from the refined EHS, SHAKE and LUSH, . and FLUSH seismic models.
- d. For the seismic requalification of component design and equip-ment in the SSWCTB, the envelopes of the FRS' curves (without any peak reduction) from the refined EHS model and the FRS curves- from the original SHAKE and LUSH, and FLUSH finite
- element models .will be used. These FRS envelopes satisfied the NRC requirements in Section 3.7.1 of the Safety Evaluation Report (SER)- (Reference 14) _ and . Section 3.7.2 of the SRP
-(Reference 5).
On these bases, the . seismic ' analysis of the SSWCTB structure and the i
seismic qualification of ~ associated component design and equipment satisfy appropriate FSAR and NRC regulatory requirements.
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5
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- - - . _ .~ - . - .
(_ QUESTION' 2 FROM THE NRC IN REFERENCE 1
' ANSWER TO QUESTION 2 FROM THE NRC IN REFERENCE 1
. The seismic SSI analysis of the Grand Gulf SSWCTB, both for determining the structural loads and for qualifying the component design and equipment 'in the SSWCTB,. is in compliance with the applicable
- provisions for SSI as ' specified in Subsection 3.7.2.11.4 of the SRP (Reference 5), to the extent indicated below:
- a. The free field seismic input was applied at the foundation level of the SSWCTB for . the EHS analyses, without deconvolution being considered. However, because of very deep embedment, for the seismic analyses of the SSWCTB based on the finite element approach, the free field seismic input was applied at top of the soll elements (approximately at grade level).
- b. The Grand Gulf site-specific seismic input was utilized for all of the seismic SSI analyses. The Grand Gulf. site-specific design (ground) spectrum curves had been found acceptable 'as in-dicated in Section 2.6.2.4 of the SER (Reference 14) and in Section 3.7.1 of Supplement 1 of the SER (Reference 4). The Grand Gulf site-specific free field surface ground acceleration time history was generated from the Grand Gulf site-specific design (ground) spectrum curves as described in the FSAR
. Section 3.7.1.2 (Reference 2).
- c. The ~ seismic design loads used for the structural design
. enveloped the seismic design loads generated from both the EHS and the finite element. approaches.
- d. The FRS curves .used for the engineering as'sessment regarding-the qualification of . the component design and equipment were -
the envelopes of the FRS curves ' generated from ' both - the -
(refined) EHS and finite element approaches.
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QUESTION 3 FROM THE NRC IN REFERENCE 1
- 3. Results of the analysis expressed in terms of floor response spectra at the key-locations and their comparison with the spectra used for
' design.
ANSWER TO* QUESTION 3 FROM THE NRC IN REFERENCE 1 Selected results of 'the seismic SSI analyses based on the EHS and finite element approaches of the SSWCTB (as described in the answer to Ques-tion 1) in terms of FRS at the key locations are exhibited in Figures 4 through 9 for the lateral (horizontal) direction and Figures 10 through 13 for the vertical direction. These key locations ~ are at Elevations 111.5, 133, and 165 feet for the lateral and vertical directions. All the FRS curves in Figures 4 through 15 correspond to 2 percent damping factor.
In each of the figures (4 through 15), there are four FRS curves, i.e.,
one obtained from the refined EHS seismic model, one from the original (SHAKE and LUSH) finite element seismic model, one from the FLUSH finite element seismic -model, and one being the envelope (used in the engineering assessment regarding the ' qualification of component design and equipment) of the first three FRS curves.
\
4 7
QUESTION 4 FROM THE NRC IN REFERENCE 1
- 4. Method of analysis of the structural members to accommodate the new results of the seismic analysis and the comparison of the cal-culated stresses with the code allowables.
ANSWER TO-QUESTION 4 FROM THE NRC IN REFERENCE 1 The seismic design loads used for the design of the SSWCTB were ob-
- tained from the original seismic model based on the EHS approach. This approach enveloped the seismic design loads produced by the refined EHS seismic model, by the SHAKE and LUSH seismic model and by the FLUSH finite element seismic model. Consequently, the original seismic design loads for the structural members of the SSWCTB remained un-affected by the subsequent analyses.
As stated in Section 3.8.4' 4.4 of the FSAR (Reference 2), the SSWCTB .
is a monolithically reinforced concrete structure analyzed elastically by using a three-dimer.sional finite element model. All applicable load combinations (per Section 3.8.6.2 of the FSAR) including seismic loads have been considered. The structural design of the SSWCTB is based on the ultimate strength design concept in accordance with ACI 318-71 Building Code Requirements.
l A ccmparison of selected critical calculated stresses with the code allcwables for the load cases with and without seismic loads is given in Table 1.
8
QUESTION 5 FROM THE NRC IN REFERENCE 1
- 5. Impact of the floor response spectra of items 3 above upon the seismic design adequacy of structural supports, equipment, pipings, and components.
ANSWER TO* QUESTION 5 FROM THE NRC IN REFERENCE 1
- As described in the answer to Question 1, the option to use the seismic analysis for. the SSWCTB with the embedment effect accounted for by the method similar to the c one developed by Beredugo and Novak (Refer-ence 12) has never been employed. Rather, for the final seismic qualification of structural supports, equipment, pipings, and components for the SSWCTB, the following envelopes.will be used in conformity with the NRC structural Engineering Branch position and Seciton 3.7 of the SRP:
- a. The FRS curves (without any peak reduction) from the refined
, seismic model based on the EHS (lumped parameter) approach.
- b. The FRS curves from the~ original' (SHAKE and LUSH) seismic model based on the finite element approach.
- c. . The FRS curves from the refined (FLUSH) seismic model based on the finite element approach.
- However, an engineering assessment of the impact of the enveloped spectra on the design qualification of all existing structural supports, equipment, and components has been performed, as . shown. In Tables 2 through 4. This evaluation indicated the need to modify nine existing pipe- supports and add four pipe supports; no other hardware modifica-
- t ions were identified as _being necessary.
. As_ indicated in the October 14, 1983 letter (AECM-83/0645) from MP&L to the NRC -(Reference 9), MP&L will complete all 'of .these required modi--
fications prior to start-up following the' first refueling outage; this'is
~
. consistent with Operating License Condition 2.c.(6).
~
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REFERENCES
- 1. Letter dated October 29, 1984 from E. G. Adensam of United States Nuclear Regulatory Commission to J. B. Richard of
' Mississippi Power & Light Company on the subject of Grand Gulf Unit-1 Seismic Analysis of the Standby Service Water Cooling
- Tower Basin, Grand Gulf Nuclear Station Unit 1.
- 2. FSAR,' Volumes 2 and 4, Grand Gulf Nuclear Station Unit 1, Mississippi Power & Light Company.
- 3. " Seismic Analysis of Structures and Equipment for Nuclear Power Plants," Bechtel Topical Report, BC-TOP-4, September
'1972, Bechtel Power Corporation.
4.. " Safety Evaluation Report Related to the Operation of Grand Gulf Nuclear Station Units 1 and 2," Dockets No. 50-416 -and 50-417, NUREG-0831, Supplement No . 1, Office of Nuclear Reactor Regulation, U.S. Nuclear Regulatory Commission, December 1981.
- 5. " Seismic System Analysis," Section 3.7.2, Standard Review Plan, NUREG-0800 (formerly NUREG-75/087), Rev.1, Office of Nuclear Reactor Regulation, U.S. Nuclear Regulatory Com-mission, July,1981.
- 6. Letter Dated July 9,1982 (AECM-82/316) from L. F. Dale of Mississippi Power & Light Company to H. R. Denton of United
^ States Nuclear . Regulatory Commission on the Subject of Soll-Structure Interaction.
-7.- Aspel, R. J. , " Dynamic Green's Functions for Layered ~ Media and Applications to Boundary Value Problems," Ph.D. Thesis,
~
University of California, San Diego,,1979.
~
.8. " Seismic ~ ~ Analysis of Structures and Equipment for Nuclear Power Plants", Bechtel Topical Report, BC-TOP-4-A, Rev. 3, November 1974, Bechtel Power Corporation.
- 9. " Summary of 'Soll-Structure Interaction for Grand Gulf Nuclear-Station," Attachment to Letter Dated October 14,19831(AECM-83 10645) from~ L. F. Dale of Mississippi Power & Light Company 'to H.R. Denton of U.S. Nuclear Regulatory Commission.
- 10. -
Tanaka, H. , Ohta, T. ,. and Uchiyama, S. , " Experimental and Analytical Studies of-a Deeply Embedded Reactor Building Model Considering Soll-Building Interaction (Part II)," No. K4/10, Transactions, the 6th SMIRT Conference, Paris France; April-
'1981.
10 3,
- 1. _.
E
- 11. Letter dated January 12, 1983 from A. Schwencer of U.S.
Nuclear Regulatory Commission to J. P. McGaughy, Jr. of Mississippi Power & Light Co. on the subject of Request for Additional Information About Soll-Structure Interaction.
- 12. Beredugo and Novak, " Coupled Horizontal and Rocking Vibration of Embedded Footings," Canadian Geotechnical Journal, Vol. 9,1972.
- 13. " Design Response Spectra for Seismic Design of Nuclear Power Plants ," Regulatory Guide 1.60, Rev.1, U.S. Atomic Energy Commission,1973.
- 14. " Safety Evaluation Report Related to the Operation of Grand Gulf Nuclear Station Units 1 and 2", Dockets No. 50-416 and 50-417, NUREG-0831, Office of Nuclear Reactor Regulation, U.S. Nuclear Regulatory Commission, September 1981.
- 15. " Seismic Design Parameters," Section 3.7.1, Standard Review Plan, NUREG-0800 (Formerly NUREG-75/087), Rev.1, Office of Nuclear Reactor Regulation, U.S. Nuclear Regulatory commission, July 1981.
11
Table 1 ,
Stress Sweary for SSWCT8 Structural Members '
. . C Forces / Moments / .
Stresses -
Stress Governing *'
Location Component Equation Actual Allowable Remarks .
4'-O' Reinf. 1.4D +1.7L M = 453'k Thick M = 629'k Compressive stress due to (BasinEmpty) P = 139.8k Basement combined P = 139.8k axial load ,
at E1. 82'-6" -flexure and 0.75-(1.4D+1.7L M = 356.6'k See axial load Design governed
+1.9E) P = 136.4k remarks by 1.4D+1.7L-
-(Basin Empty) (Basin Egty) !
4'-0" Concrete 1.4D+1.7L Y = 114.2k i
Thick Exterior Shear V = 131.5k Allow includes (BasinEmpty) stirrups Walls From E1. 82'-6" to 0.75 (1.4D+1.7L+ V = II4.9k E1. 112'-0* V = 131.5k Allow. includes -
1.9E) stirrups (Basin Empty)
Vertical Reinf. 1.4D+1.7L M = 418.I'k M = 642.4'k Compressive l stress due to (Basin Empty) P = 73.3k P = 73.3k axial load combined flexure and axial load 0.75 (1.4D+1.7L M = 313.6'k See Design governed by
+1.9E) P = 43.9k F (Basin Empty) remarks 1.4D+1.7L (Basin Empty)
Horizontal 1.4D+1.7L M = 527.6'k M = 746't Compressive Reinf. Stress (Basin Empty) P = 102.4k P = ID2.4k axial load Due to Con 61ned ,,
Flexure and 0.75 (1.4D+1.7L M = 495.2'k See Design governed Axial Load +1.9E) P = RS.5k remarks by 1.4D+1.7L (Basin Egty) -
(Basin Empty) 0 = Dead Load E' = SSE M = Bending Moment L = Live load Ta = Accidental To, To' = Operating Teriperature P = Axial Load Temperature E = OBE Conditions V = Shear Condition l
fs = Rebar Stress 1C0039 1Cim39
=
Table _1 (Continued)
Forces /Moinents/
Stresses
- Stress. Governing Location Component Equation Actual Allowable Remarks 3'-0" Thick cencrete 1.4D+1.7L Y = 58.3k Ext:rior twar V = 83.6k Allow. includes a
.(Basin Empty) stirrups Walls
- i From I 0.75 (1.4D+1.7L+ V = 52.9k V = 83.6k Allow. includes E1. 112'-0* 1.9E)
Ta (Basin Empty) stirrups .
El. 133'-0*
Hori. Reinf. 1.4D+1.7L M = 225.5'k M = 429'k Compressive Stress-Due (Basin Empty) P = 49.7k to Combined P = 49.7k axial load
. Flexure 0. 75 (1.4D+1.7t+ M = 87.I'k and Axial See Design governed -
1.9E) P = 58.71 remarks by 1.4D+1.7L Load (BasinEmpty) (Basin Empty)
Extcrior Vertical 0.75 (1.4D+1.7L+
Wall V = 15.96k V = 19.Jk Concrete Shear 1.4 To +1.9E)
From E1. 144'-6" Horizontal 0.75 (1.4D+1.7L+ V = 40.2k to V = 57.8k Allow includes Concrete Shear 1.4 To +1.9E)
E1, 166'-0* stirrups Vertical Rebar 0.75 (1.4D+1.7L+ fs=32.14ksi fs=54ksi Stress Due to 1.4 To +1.9E)
Combined Flexure and Axial. Tension .
~.,*
Horizontal Rebar. 0.75 (1.4D+1.7L+ ' Ts=J4.8ksi fs=54ksi Stress Due to 1.4 To +1.9E)
Combined Flexure and Axial Tension IC0039 , 100039
. . l' Table 1 (Continued) -
Forces / Moments /
Stresses '
Stress Governing Location Component _ Equation
- Actual Allowable Remarks 2'-0* Thick Concrete Interior Shear 1.00+1.0L+1.0E' V = 23.6k V = 30k -
Divide Wall (Basin Full)
E1. 82'-6" Vert. Reinf.
t3 1.00+1.0L+1.0E' M = 92.4'k M = 200'k Compressive Stress Due to (Basin Full)
E1. 133'-0* Codined Flexure P = 68.7k P = 68.7k axial load t and Axial Load '
2'-0" Thick Vertical Interior U.75 fl.4D+1.7L+ V = Ilk V = 26k Concrete Shear !
- Divide . 1.4To+1.9E)
Walls From Horizontal i El. 144'-6" 0.75 (1.4D+1.7L+ V = 14.7k V = 15.9k Concrete Shear 1.4To+1.9E) A110wahl: reduced l to for axial tension E1. 166'-0= vertical Rebar '
U.75 !1.4D+1.7L+ Ts=24.19ksi Ts=54ksi Compressive Stress Due to 1.4To+1.9E)
Combined Flexure axial load
.and Axial Load .
Horizrntal Rebar 0.75 fl.4D+1.7L+ Ts=24.86ksi Stress Due to fs=54ksi Compressive 1.4To+1.9E)
Combined Flexure axial load l and Axial Load :
2'-0" Thick 4 .
Peinf. Stress 1.4D+1.7L ,,,* '
i Roof Slab Due to Combined (Basin Empty) F1 = Il2.5'k M = 173.7'k Compressiv.e l at Flexure and '
P = 30k P = 30k axial load i E1. 133' -0" - Axial Load l
0.75 (1.4D+1.7L+ M = 95.5'k See Design governed 1.9E! P = 30.4k remarks l (Basin Empty) by 1.4D+1.7L i
fBasin Empty) j%
I IC0039
- 1C0039 ,
.e .1 Table 1 (Continued) *
} , .
Forces / Moments /
Stresses
. Stress Governing Location Component Equation ;
Actual Allowable. Remarks 2'-0* Thick q Reinf. Stress 1.00+1.0L+
Roof Slab Due to Combined fs=41.11ksi fs=54ksi
- i at 1.0(Ta+To)+1.0E' Flexure and E1. 166'-0* Axial Tension 4'-0" Dia.
Reinf. Stress 1.00+1.0L+1.0E' M = 1715'k Col. From Due to Conbined M = 1949'k I El. 82'-6" to (Basin Full) P = 1612k P = 1612k Flexure and l' E1. 133'-0*
Axial Compression '
- t 10'x27" Reinf. Stress Fill Support 0.75 (1.4D+1.7L+ M = 4728"k M = 5249't Compressive Due to 1.4 To)
Beam Ci,mbined P = 151.5k P = 170k axial load at Flexure and t
E1. 144'-6" Axial Load 0.75 (1.4D+1.7L+ M = 5158"k M = 5249"k Compressive 1.4 To + 1.9E) P = 170k P = 170k axial load 0.75 (1.4D+1.7L M = 3715.4"k M = 5921"k Tension
+1.4 To')
P = 443.2k P = 443.2k axial load 8"x18" Concrete Distribution 0.75 (1.4D+1.7L V = 51.7k V = 53.33k ~-
Shear +1.4 To') Allowable includes n -
System stirrups' .
Support Beam .
Reinf. Stress 0.75 (1.4D+1.7L ,
at Due to Combined M = 1589.7"k M = 2168"k Tension axfal
} E1. 157'-6" +1.4 To') P = 180k P = 180.5k load F'sexure and !
} Axial Load '
b 0.75 (1.4D+1.7L
+ 1.4 To+1.9E)
M = 1699"k P = 180.5k M = 2168"k Tensfon exfal Toad t
P
= 180.5k 1C0039 - "~~~~
l TABLE 2 l
l Results of mechanical equipment and commodity seismic qualification based on the envelopes of the floo.r response spectral (FRS)' curves from the 1 SHAKE / LUSH, FLUSH, and EMS (lumped parameters) seismic SSI models for the SSWCTB. i l
~
Item No.
- Item Seismic Qualification Results 1 Fan Motor The fundamental frequency of the motor is greater than 33 Hz. Per original seismic qualification l analysis, the fan motor compon-
- ents have avallalle margins be-tween 43 and 770 percent of the 3 calculated critical deflection !
values and a minimum of 2300 per- l cent of the calculated stresses. .
Per the supplier of.the fan motor, l similar motors were qualified for higher g values (0.58g horizontal and 0.33g vertical), which are !
higher than the ZPA accelerations l of the applicable FRS envelopes.
By inspection, the fan motor re-mains lopes. qualified to the FRS enve-2 Cooling Tower: Ceramic The ceramic fill behaves as a Fill rigid body. For the ceramic fill to slip, the lateral acceleration I must exceed 0.63g (static friction force). The ZPA accelerations of all the FRS envelopes are less than 0.4g. Thus, the ceramic fill cannot slip, i.e., it is seismically qualified.
~
3 Cooling Tower: ' Cast Iron The lintels behave as rigid mem-Lintels bers. With allowable stresses limited to one-half of the ultimate stresses, the minimum margin based on the FRS envelopes is
~ 69 percent of the calculated
, stresses.
4
'The total number of items is 15.
16
)
- TABLE 2 (Ccndnued)
I.
Item No.* Item Seismic Qualification Results 4 Cooling Tower: Extren Based on original qualification.
Beams these extren beams have very low stresses and a minimum margin available of 7400 percent of the calculated stresses. By inspec-tion , they remain qualified to the FRS envelopes.
5 Piping, Pipe Supports, Piping has been analyzed / eval-and Motor Operated uated for the FRS envelopes.
Valves All piping stresses remain with-in code allowable values. How-ever to meet the manufacturer's nozzle allowable loads for the SSW pumps and increased loads for pipe supports, nine existing supports need to be modified and four additional supports need to be installed. Also all motor operated valves were determined to have seismic accelerations below the qualified limit of 3g's in two directions and are acceptable for the FRS enve-lopes.
6 Cooling Tower: Fan In the original qualification, the Blades fan blades were qualified con-servatively to vertical accel-erations of 1.04g and 0.22g at the fundamental frequencies of 6.9 and 21.5 Hz, respectively.
The fan blades have a minimum margin available of 600 percent of the calculated bending moment.
With the FRS envelopes (1 per-cent damping), the vertical acceleration is lower (0.92g) at 6.9 Hz and remains the same (0.22g) at 21.5 Hz. Therefore, by inspection, the fan blades remain qualified to the FRS envelopes.
7 Coo!!ng Tower: Gear The gear reducers were origi-nally qualified conservatively Reducers by static coefficient analysis using peak spectral accelera-tions. Safety margins of 39 to 3000 percent are available over the calculated stresses. The 17 o,
p TABLE 2 (Continued)
Item No.* Item Seismic Qualification Results 7 Cooling Tower: Gear gear reducers do not 'have any Reducers fundamental frequencies below (Continued) 33 Hz. The ZPA ' values of the
~ FRS envelopes are much lower than the peak accelerations used in the original qualification.
Therefore, by inspection, the gear reducers remain qualified to the FRS envelopes.
8 Cooling Tower: Drive Based on the original qualifi-Shaft cation, this drive shaft has a minimum margin available of 16,000 percent of the calculated stresses. By inspection, it remains qualified with the FRS envelopes.
9 Cooling Tower: 1/4-inch Based on the original qualifi-Diameter U-Bolts cation, these 1/4-inch diameter U-bolts have a minimum margin available of 6500 percent of the calculated stresses. By inspection, they remain quali-fled with the FRS envelopes.
10 Cooling Tower: ' Drive The design is governed by tor-Motor Bolts nado loads. The tornado loads exceed the seismic loads. Tor-nado analysis shows .that the bolts have a minimum margin available of 700 percent cf the calculated stresses. By inspec-tion, they remain qualified to .
the enveloping FRS.
11 HVAC System: Ductwork These were originally designed and Supports to conservative spectra which envelop the FRS envelopes. By inspection, the ductwork and supports remain qualified to the FRS envelopes.
12 HVAC System: Dampers The fundamental frequencies of and Actuators the dampers are 225 Hz. These dampers were originally qualified to 5.4g, which is much higher than the spectra from the FRS envelopes from 25 Hz and upward. Thus, the dampers ,
18
i TABLE 2 (Continued) ,
Item No.* Item Seismic Qualification Results
. 12 HVAC System: Dampers remain qualified. In the orig-
- and Actuators (Continued) inal qualification. for the actuators, multi-axis multifre-quency (between 1 and 40 Hz)
' sine beat tests were performed.
' The accelerations in the sine beat tests at various frequen-cies are higher than the accele-rations of the FRS envelopes at the same frequencies. Therefore, by inspection, the actuators re-main qualified to the FRS envelopes.
13 HVAC System: Vane Axial The lowest natural freugency of rans and Motors the fan / motor assembly is much greater than 33 Hz. Based on original static analysis, these vane axial fans and motors have a minimum margin available of 1140 percent of the calculated stresses. Additionally, the ZPA values used in the original analysis are higher than the ZPA values of the TRS envelopes.
Therefore, the fan / motor assem-bly remains quallfled to the PBS envelopes.
14 SSW and HPCS Pump Motors These motors werc ; ' r! inally qualified by static coefficient analysis. The accelerations used in the analysis are higher '
than the peak accelerations of-the FRS envelopes for OBE (1 percent damping) and SSE (2 percent damp ng). Thus, by inspection, the - SSW and ' HPCS pump motors remain quallfled to-
, the FRS envelopes.
15 -
SSW and HPCS Pumps The SSW and HPCS SW pumps were seismically analyzed using
~ TRS envelopes. The method of analysis was similar to the ,
original qualification seismic of those pumps. Stresses were calculated for normal,- upset, and faulted conditions. All stresses ^ were found to be with- ,
in ASME Code allowables, 19
TABLE 3 Results of control system equipment seismic qualification based on the envelopes gf the floor response spectral curves from the SHAKE / LUSH, FLUSH, EHS (lumped parameter) seismic SSI models for the SSWCTB Item
.. No.* Item .
Seismic Qualification Results 1 Transmitters, Rosemount These transmitters were origin-Models 1151 and 1153 ally qualified with test response spectral (TRS) curves, which envelo the present FRS enve-lopes.p By inspection, these transmitters remain quallfled.
2 Ther.nocouples by Thermo- These thermocouples were origin-electric ally qualified with test response spectral (TRS) curves, which envelop the present FRS enve-lopes. By inspection, these thermocouples remain qualified.
- The total number of items is 2. .
tu
~
TABLE 4 Results of electrical equipment seismic qualification based on the enve-lopes of the floor response spectral curves from the SHAKE / LUSH, FLUSH, EHS (lumped parameter) seismic SSI models for the SSWCTB Item
... No.* Item Seismic Qualification Results 1 Load Centers This equipment was originally qualified with test response spec-tral (TRS) curves, which envelop the present FRS envelopes. By inspection, this equipment remains
, qualified.
2 Motor Control Centers This equipment was originally qualified with test response spec-tral (TRS) curves, which envelop the present FRS . envelopes. By inspection, this eqolpment remains qualified.
P
'The total number of items is 2.
21 A
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