ML20084D853
| ML20084D853 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 04/27/1984 |
| From: | Woolever E DUQUESNE LIGHT CO. |
| To: | Knighton G Office of Nuclear Reactor Regulation |
| References | |
| 2NRC-4-047, 2NRC-4-47, NUDOCS 8405010495 | |
| Download: ML20084D853 (48) | |
Text
O 2NRC-4-047 (412)787 - 5141 Telecopy 29 Nuclear Construction Division April 27, 1984 Robinson Plaza, Building 2, Suite 210 Pittsburgh, PA 15205 United States Nuclear Regulatory Commission Washington, DC 20555 ATTENTION:
Mr. George W. Knighton, Chief Licensing Branch 3 Office of Nuclear Reactor Regulation
SUBJECT:
Beaver Valley Power Station - Unit No. 2 Docket No. 50-412 NRC Structural Design Audit Gentlemen:
In letter 2NRC-4-018, dated February 27, 1984, we provided you with a res ponse or a schedule for providing a res ponse to each of the 28 NRC Structural Design Audit Act ion Items and to each of the NRC Structural Engineering Sect ion's review comments on BVPS-2 Standard Review Plan dif-ferences. Attached are the responses that were scheduled to be provided by April 27,1984 (Action Items 1, 6, 13, 14, 15, 16, 21, 2 2, and 28, and S RP S ect ions 3.3.1. II.3 and 3.7.3.11.7 ) and three of the res po ns es that were scheduled to be provided by June 15, 1984 ( Act io n It ems 5, 11, atti 24).
I f you have any que s tions on this matter, ple ase cont ac t J. D.
O'Neil at (412) 787-5141.
DUQUESNE LIGHT COMPANY By
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M.(/J."Wooleve r Vice President JD0/wjs At tachment ec:
Mr. G. Walton, NRC Resident Inspector (w/a)
Mr. M. Lacitra, Project Manager (w/a) bdBSCRIBED AND SWORN TO BEFORE M! THIS J g,D Y OF Mfwd
, 1984.
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!_NM MUs k
Notary Public
!.d.% 0. LLECNDAK, NOTARY PUBLIC
. ROSINSON TOWNSHIP, ALLEGHENY COUNTY f
MY COMMISS!ON EXFIRES OCTOBER 20,1986 I
e 8405010495 840427 I
PDR ADOCK 05000412 A.
e Unitsd Stctes Nucisar Rrgulatory Conunission Mr. Gzorge W. Knighton, Chief Page 2 COMMONWEALTH OF PENNSYLVANIA )
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COUNTY OF ALLEGHENY
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On this j d d day of ow,)
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, be fo re me,
a Notary Public in and for said Commonwealth sad County, pe rsonally appeared E. J. Woolever, who being duly sworn, deposed and said that (1) he is Vice President of Duquesne Light, (2) he is duly authorized to execute and file the foregoing S ubmit t al on behal f of said Company, and (3) the s tatement s set forth in the Submittal are true and correct to the bes t of his knowledge, sd
, / An< bb j/
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Notary Public
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ELVA G. LESONDAK, NOTARY PUBLIC ROBINSON TOWNSHIP, ALLEGHENY COUNTY MY COMMISSION EXPIRES OCTOBER 20,1986
NRC STRUCTURAL AUDIT ACTION ITEMS 1.
The applicant intends to demonstrate that the site-specific response spectra approved by the NRC's Geosciences Branch will be comparable to that shown on FSAR Figure 3.78-1 and any significant differences will be addresse'd and justified.
The applicant will also address the deviations of the vertical spectra from those given in Regulatory Guide 1.60 as it is applicable to the BVPS site.
Response
This item is addressed in the attached responses to NRC Geosciences Branch questions 230.2, 230.3, and 230.6, and NRC Structural Engineering Section question 220.4.
The separate report referred to in these responses, entitled " Seismic Design Response Spectra, BVPS-2", will be provided by June 1, 1984.
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i BVPS-2 FSAR NRC Letter: September 19, 1933 Question 230.2 (SKPs 2.5.2.3. 2.5.2.4, 2.5.2.5 and 2.5.2.6)
According to the FSAR, the BVPS-2 seismic design parameters are based upon a response spectrum anchored to a 0.125g ZPA which is different from the Regulatory Guide 1.60 spectrum. The documents quoted for the development of the above seismic design spectrum are BVPS-2 PSAR Appendixes 2C and 20.
BVPS-2 Appendix 2C recommends a 0.10g design earthquake.
BVPS-2 Appendix 2D recommends a Housner response spectrum normalized to 0.125g which was obtained from an estimated amplification factor of 3.5 combined with a
maximum ground acceleratien of 0.035g.
In addition to these multiple assumptions, there are several facters mentioned in the FSAR which have not been adequately discussed with respect to the influence that these factors have on the seismic design criteria for the plant. For example, FSAR Table 3.7B-12 indicates variations in depth of soil ever bedrock from 35 feet to 100 feet. FSAR Figures 2.5.4-2 through 2.5.4-9 indicate significant differences in density of soils underlying the Category I structures.
Describe how the above information was used to determine the seismic design criteria for each of the Category I structures.
For example, describe the free field foundation acceleration assumed for the seismic design of Category I structures.
Describe how the established free field foundation acceleration was augmented to accommodate for soil amplification or reduction.
1
Response
Refer to revised Section 2.5.2, Amendment 6, and a separate report entitled, Seismic Design Response Spectra, BVPS-2, which will, be submitted, to the NRC under separate cover in response to MRC l
Structural Design Audit Action Item 1.
Amendment 6 Q230.2-1 April 1984
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t BVPS-2 FSAR l
NRC Letter: September 19, 1933 Questien 230.3 (SRPs 2.5.2.3, 2.5.2.4, 2.5.2.5, and 2.5.2.6)
The site is considered to be located in the Appalachian Plateau Tectenic Province. The largest historic earthquake in this tectonic province was dete rmined to be the November 6,
1926 S.E. Ohio earthquake. This determinaticn was obtained from intensity listings shown in the FSAR Table 2.5.2-2.
Using the Standard Review Plan procedure for deriving seismic design criteria from intensity data, the MMI=V!-VII intensity listed for the 1926 earthquake would indicate a Regulatory Guide 1.60 response spectrum anchored to 0.10g
- ero period acceleration which may be codified to reflect local site conditions.
In recent safety reviews, the staff has relied upon site specific spectra to evaluate the seismic design criteria.
The reason being that site specific spectra are more in accord with the controlling earthquake size, frequency spectrum, and local site. conditions.
For example, using the Nuttli/Herrmann (1978) relationship, the site specific spectra for a MMI=VI-VII intensity earthquake could be developed from :he 84th percentile spectra of a suite of appropriate earthquake records of magnitude m
= 5.0 + 0.5.
In addition, a
direct estimate of magnitude may be obtained from the information listed in the updated FSAR Table 2.5.2-2.
In the event that appropriate records are not currently available, a site specific spectrum may be determined by modifying a rock site specific spectrum to accound for local soil amplification characteristics of the site (refer to Midland OL-SER, Clinton OL-SER).
1.
Using the guidelines described in the Standard Review Plan (1981) compare the BVPS-2 design spectra to the appropriate intensity based on Regulatory Guide 1.60 spectra. Describe the effects of local site conditions and discuss exceedences, if any.
2.
Based upon your estimate of the appropriate magnitude of the Safe Shutdown Earthquake prepare Site Specific Spectra in accordance with guidelines described above. Compare these spectra with the design spectra for the plant and discuss exceedences, if any.
Include in your discussion the effects of the following variations in parameters which influence the ground motion estimates:
a.
Variation in shear velocity in the soil layers which depend upon the composition, depth, and/or densification of soil layers under the Category I structures, b.
If appropriate, compare results of layered soil analysis programs to methods other than those used in Appendix 2D, such as SHAKE.
Amendment 4 Q230.3-1 December 1983
(
BVPS-2 FSAR
Response
Refer to revised Section 2.5.2, Amendment 6, and a separate report entitled, Seismic Design Response Spectra, BVPS-2, which will be submitted to the NRC under separate cover in response to NRC Structural Design Audit Action Item 1.
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I Amendment 6 Q230.3-2 April 1984
BUPS-2 FSAR NRC Letter: September 19, 1983 Question 230.6 According to the FSAR section 3.7B.1.1 the vertical design response I
spectra are taken to be two-thirds of the horizontal design response spectra.
Discuss the adequacy of the vertical response spectra with respect to the Regulatory Guide 1.60 procedures for determining the vertical response spectra (reference hegulatory Guide 1.60, Table II). Include in your discussion relevant information obtained from the recent eastern U.S. and Canada earthquake records (1982 New Hampshire and New Brunswick earthquakes).
Response
Refer to revised Section 2.5.2, Amendment 6, and a separate report entitled, Seismic Design Response Spectra, BVPS-2, which will be submitted to the NRC,.under separate cover in response to NRC Structural Design Audit. Action Item 1.
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I Amendment 6 Q230.6-1 April 1984
BVPS-2 FSAR NRC Letter: September 15, 1983 Question 220.4 (Section 3.78.1.1 SRP 3.7.1.II.la)
Referring to Item 3.7.1.II.la discussed in " Priority Review of Beaver Valley 2 Standard Review Plan Differences,"
the site specific response spectra and the values of vertical design response spectra should be addressed in Section 2.5.
Response
Refer to revised Section 2.5.2, Amendment 6, and a separate report entitled, Seismic Design Response Spectra, BVPS-2, which will be submitted to the NRC under separate cover in response to NRC Structural Design Audit Action Item 1.
Amendment 6 Q220.4-1 April 1984
NRC STRUCTURAL AUDIT ACTION ITEMS 5.
For each of the three key structures identified in Item 4, consider the base mat shear forces due to earthquakes and assess the impact of in-cluding additional accidental torsional effects, and show that the structural elements are adequate for these effects.
Response
The auxiliary building is considered to be representative of the seismic Category I structures at BVPS,2; as such it was chosen for the purpose of assessing the impact of including the accidental torsional effects.
The resultant torsion at the base of the structure was calculated by assuming the resultant. story shears to be offset from the center of rigidity by 5 percent of the maximum building dimension perpendicular to the direction of the applied story shear.
This resultant torsion i
was distributed to the walls, at the base of the structure, in proportion to their relative stiffnesses and distances from the center of rigidity.
A summary of results is presented in Table 5.1.
It can be seen from 1
j Table 5.1 that the effects of accidental torsion are very small and the l
structures have adequate strength to carry this arbitrary loading, t
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l T bic 5.I Wall old 81d V
V,,y Ag,w A
Designation V
T provided (kips)
(in2/ft)
(kips)
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(in2/ft)
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A 915 0.72 65 980 0.72 3.74 B
6867 1.32 402 7269 1.39 3.74 C
4035 1.08 157 4192 1.08 1.20 D
5256 0.72 314 5570 0.72 3.74 E
4165 0.72 236 4401 0.72 3.74 Vold = Shear in wall due to story shears and actual eccentricity.
T
= Shear in wall due to specified ' accidental eccentricity.
yaccid V,,, = Vold + celd.
31d = Area of reinforcement required for Vold*
A Ag,y = Area of reinforcement required for Vnew' Alrovided" Area f reinf Icement provided.
- Amin = Minimum area f reinf reement required per ACI 318 Section 11.16.4.1 governs
( p = 0.0025).
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NRC STRUCTURAL AUDIT ACTION ITEMS 6.
Assess the safety factors against sliding and overturning of both the containment and auxiliary building structures by accounting for the three component earthquake input.
Response
Factors of safety against sliding and overturning that account for three-component earthquake input have been calculated for the auxiliary l
building.
The auxiliary building was chosen as representative of Seismic Category I buildings at BVPS-2.
l Haximum floor acceleration responses were calculated in accordance with the acceptance criteria of SRP 3.7.2 (that is, "when the response l
spectra method is adopted for seismic analysis, the maximum structural responses due to each of the three components of earthquake motion should be combined by taking the square root of the sum of the squares of the maximum codirectional responses caused by each of the three i
components of earthquake motion at a particular point of the struc-l ture").
This method is demonstrated in Table 6.1 for the case of horizontal acceleration response in the north-south direction due to three component earthquake input.
This procedure was repeated to obtain the building acceleration response in the east-west and vertical directions.
From these calculated floor accelerations the shear and overturning moments at the base of the structure were obtained by summation of inertia forces.
Sliding and overturning loads with respect to both axes, east-west and north-south, of the building have been calculated in this manner.
Factors of safety against sliding and overturning were then calculated as described in FSAk Section 3.8.
The results obtained are presented in Table 6.2 for the SSE case.
Inspection of resulting loads on the foundation show that the SSE case governed over the OBE case. Sliding forces were resisted by friction at the soil / mat interface. Overturn-ing was resisted by a linear distribution of bearing stress under the foundation mat.
In conclusion, the factors of safety against sliding and overturning have been computed
- for the auxiliary building considering the three-component earthquake input and are within the limits specified in FSAR Table 3.8-13.
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TABLE 6.1 2
Three-Component Earthquake Response in N/S Direction (ft/sec )
Contribution Contribution Contribution Floor
Response
From E-W From N-S From Vertical SRSS Elevation Direction Excitation Excitation Excitation Resultant 710'-6" N-S 0.36 6.51 0.71 6.56 735'-6" N-S O.26 7.83 0.55 7.85 l
755'-6" N-S 0.26 9.31 0.47 9.33 773'-6" N-S 0.32 10.73 0.45 10.74 797'-6" N-S 1.04 13.60 0.79 13.67 I
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TABLE 6.2 Factors of Safety (SSE Earthquake)
East / West Direction North / South Direction BVPS-2 Condition Factor of Safety Factor of Safety FSAR Limit i
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l Sliding 1.6 2.2 1.1 1
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NRC STRUCTURAL AUDIT ACTION ITEMS
- 11. Perform a random and limited review of actual design calculations to ensure that the stress and strain levels of key structural elements are consistent with Position C.3 of Regulatory Guide 1.61.
Response
Position C.3 of Regulatory Guide 1,61 requires that the maximum com-bined stresses due to static, seismic, and other dynamic loadings, not be significantly lower than the yield stress and 1/2 yield stress for SSE and 1/2-SSE, respectively, if the Regulatory Guide 1,61 dampings are to be used.
A review of the design calculations for the lower walls of the auxiliary building and safeguards building was performed to determine the corresponding stresses.
The results of this review show the stresses in the wall (reinforcing steel) to be significantly lower than those identified in Position C.3.
For the 1/2-SSE analysis of structures at BVPS-2, a value of 2 percent of critical damping was used for reinforced concrete structures; this is 50-percent less than the corresponding value identified in Regulatory Guide 1.61.
For the SSE analysis, the BVPS-2 damping value is the same as that identified in Regulatory Guide 1,61 (that is, 7.0 percent of critical damping).
The structures at BVPS-2 are founded on soil; as such the dynamic responses due to seismic excitation are dominated by the soil deforma-tions.
In fact it can be seen from the results of the dynamic analysis of the soil-structure models that the system dampings (modal dampings) are mainly a function of the soil damping for the predominant modes.
To demonstrate this, the soil-structure model of the auxiliary building was reanalyzed for the SSE case, using a damping of 1.0 percent of critical for the structural elements. The soil damping values were not changed. Table 11.1 demonstrates clearly that the seismic responses of BVPS-2 structures are insensitive to variations in steel and concrete structures.
Since the results of the two analyses are essentially identical, it is concluded that the values of damping used for the seismic analysis of structures at BVPS 2 are acceptable.
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l TABLE 11.1 Calculated Accelerations and Displacements Accelerations (g)
Displacements (ft) l Elevation Direction (ft)
Case I Case II Case I Case II North-South 797.25 0.43 0.43 0.045 0.046 North-South 772.50 0.33 0.34 0.036 0.037 1
i North-South 754.50 0.29 0.30 0.032 0.032 North-South 735.50 0.24 0.25 0.026 0.027 North-South 709.00 0.20 0.21 0.019 0.020 East-West 797.25 0.45 0.46 O.051 0.052 East-West 772.50 0.33 0.34 0.039 0.040 East-West 754.50 0.28 0.28 0.033 0.034 East-West 735.50 0.23 0.23 0.026 0.026
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East-West 709.00 0.20 0.20 0.017 0.018 Vertical 797.25 0.29 0.29 0.017 0.020 1
Vertical 772.50 0.26 0.26 0.017 0.017 Vertical 754.50 0.26 0.26 0.017 0.017 Vertical 735.50 0.25 0.25 0.016 0.017 Vertical 709.00 0.24 0.23 0.016 0.016 i
NOTE:
Case ! = 7.0% structure damping Case !! = 1.0% structure damping l
NRC STRUCTURAL AUDIT ACTION ITEMS
- 13. Provide technical justification for using a dynamic amplification factor of one for the analysis of pressurization ef fect on steam generator cubicles. Also, address the basis for not accounting for the cracking effect of the concrete elements during pressurization.
Response
An elastic dynamic analysis has been performed for the steam generator cubicles when subjected to the time history of pressurization load (Figure 13.1).
The fundamental frequencies of the floor slabs, cranewall, and radial walls of the cubicles have been calculated for both the uncracked and cracked concrete conditions.
For the governing structural element (a radial wall) the uncracked and cracked frequencies are 37 Hz and 27 Hz, t
respectively.
The pressure time histories were applied to each of these structural element models and the resulting damped equations of motion were numerically integrated to determine Dynamic Load Factors (DLF).
Results of these analyses justify th.e use of a DLF = 1.0 for the pressure load P throughout the steam generator cubicle (the maximum calculated DLF was 1.04),
i A confirmation program is currently underway to verify the design of the containment's internal structure (including steam generator cubi-cles) for final pressure loads.
Methods similar to those described above will be used to determine the appropriate DLFs for the final i
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NRC STRUCTURAL AUDIT ACTION ITEMS
- 14. The applicant is requested to provide comparisons to demonstrate that the current SRP structural acceptance criteria (3.8.2) for design limits and loading combinations are complied with.
Deviations identified by the comparison should be justified.
Response
As stated in FSAR Section 3.8.2.2 and as defined in the " Codes and Standards" Section of 10CFR50.55a, DVPS-2 is governed by the 1971 edition of the ASME B&PV Code,Section III, Division 1, up through and including the Winter 1972 Addenda.
The edition in effect at the time of SRP 3.8.2 Rev.1 (7/81) was ASME III 1980.
A comparison has been performed to determine the deviations between the current SRP 3.8.2 acceptance criteria for design limits and loading combinations and the corresponding criteria specified for BVPS-2.
The comparison resulted in the finding that the loading combinations and design limits of BVPS-2 are in close, agreement with SRP 3.8.2 Rev. 1.
The minor deviation noted below results exclusively from dif-ferences in the applicable edition of the ASME III Code for BVPS-2 and the applicable edition in effect at the time of Rev. I of SRP 3.8.2.
The deviation in the combinations and/or limits is that stress limits for the test condition are reduced somewhat in the 1980 version of the ASME code. Test condition allowable stresses are:
General Local Bending and Local Membrane Membrane Membrane 1971 ASME Code:
0.90 Sy 1.25 Sy 1.25 Sy 1980 ASME Code:
0.75 Sy 1.15 Sy 1.15 Sy The design of those portions of the BVPS-2 containment covered by ASME Section III, Division 1, is not governed by the test condition; thus this change is not considered significant.
NRC STRUCTURAL AUDIT ACTION ITEMS 15.
The applicant should identify and justify the deviations of its in-ternal structural design from the applicable requirements of the ACI-349 as amended by Regulatory Guide 1.142.
Response
A review has been performed to identify the significant differences between the requirements for the BVPS-2 design of the internal struc-ture of the reactor containment (FSAR Section 3.8.3), and the require-ments of ACI 349-76 as amended by Regulatory Guide 1.142.
The results of this review are summarized in Table 15.1; justifications of differences in design requirements are also given.
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Table 15.1 Comparison of Concrete Design Criteria for Containment Internal Structures l
Regulatory Guide Code 1.142 Section ACI 318-71 ACI 349-76 Rev. 1, Oct 1981 Justification Chapter 1 Requires copies of struc-Requires copies of struc-BVPS-2 drawings and General Req.
tural drawings, typical tural drawings, typical specifications bear
. details and specifica-details, and specifications the signatures of tions to bear the seal be signed by licensed licensed engineers.
of a licensed engineer.
engineer.
Requires inspection by a Requires inspection by Recommends inspectors Inspections are competent engineer.
Owner.
be experienced and performed by a familiar with ACI and BVPS-2 Quality Con-ASTN standards.
trol representative.
Chapter 2 Massive concrete not Requires areas to be Current practice is Definitions specifically mentioned, treated as massive con-in accordance with crete to be identified ACI 349. BVPS-2 on drawings or concrete specifica-specifications.
tions define the areas to be treated as massive concrete.
Chapter 3 Excludes use of air-BVPS-2 concrete Materials entraining Portland specification meets Cement.
the intent of ACI i
349 by requiring that only Type II low alkali cement be used.
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Tr.ble 15.1 (Crnt'd)
Regulatory Guide Code 1.142 Section ACI 318-71 ACI 349-76 Rev. 1, Oct 1981 Justification No test reports required.
Requires test report on BVPS-2 specifications every cement shipment. No require mill tests cement can be used prior to for each shipment.
receipt of 7 day mill test Results are verified strengths.
for conformance to ASTM C150 before use of cement is allowed.
Allows the use of light-Excludes use of light-Lightweight concrete weight aggregate concrete.
weight aggregate concrete.
was not used at BVPS-2 for structur-al applications.
Materials must conform Testing requirements BVPS-2 specifications to applicable ASTM established for aggregrate, are in conformance specification.
reinforcing steel, and with ACI 349.
admixtures.
Not required.
Reinforcing steel shall be BVPS-2 specifications identifiable by documenta-are in conformance tion, tags or other means with ACI 349.
of control, to a specific heat number or heat code until review of the Certified Materials Test Report has been performed.
Allows.use of rail steel and Requires use of billet steel Reinforcing steel axle steel bars. Allows reinforcing bars of Grade 60 specification and Grade 90 bars.
or less, in order to limit drawings require that crack formation.
rebar comply with ASTM A615 grade 50 for No. 14's and No. 18's and grade 60 for No.11's and smaller.
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Table 15.1 (Cont'd) l Regulatory Guide Code 1.142 Section ACI 318-71 ACI 349-76 Rev. 1, Oct 1981 Justification Chapter 4 Allows proportioning of six Requires that mix design be BVPS-2 concrete Concrete Quality design using water-cement based on field experience specifications l
ratio tables in lieu of or laboratory trial batches.
require that mixes
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field experience or trial be determined by l
batch methods of propor-trial batches.
tioning mix.
Provides method of deter-Fly ash mixes are mining water / cement ratio not used in BVPS-2 for fly ash mixes.
structures.
Requires use of Type V Defines sulfate exposure Sulfate exposure is cement for sulfate exposure. limit. Requires Type V not a problem for cement or a fly ash mix for the concrete struc-sulfate exposure conditions.
tures at BVPS-2.
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Requires I strength test /
Permits test interval in-Similar to ACI 349 Current BVPS-2 3
day / concrete class and at crease by 50 yd /100 psi except at least once practice is in least once for each 150 cu lower standard deviation if for each 100 cu yd accordance with
-'~~
yd of concrete placed or standard deviation for 30 placed unless other-Reg. Guide.
l for each 5,000 sq. ft of tests in a class is less wise qualified.
concrete surface.
than 600 psi. Not less than once per shift.
Chapter 5 Prohibits use of aluminum BVPS-2 concrete Cixing and pipe and chutes for con-specifications are j
Placing Concrete veying concrete.
in accordance with ACI 349.
Allows partially hardened, Prohibits use of such BVPS-2 concrete contaminated, retempered, or material.
specifications com-remixed (after initial set) ply with ACI 349.
concrete to be used at the discretion of the engineer.
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T :ble 15.1 (Cont'd)
Regulatory Guide Code 1.142 Section ACI 318-71 ACI 349-76 Rev. 1, Oct 1981 Justification Chapter 6 Requires pressure test of Requires pressure test of BVPS-2 complies with Form Wrk embedded pipe to 50 percent embedded pipe "in accordance the position taken Embedded Pipes, above max. pressure (150 psi with the applicable piping in ACI 349.
and Construction min.) for 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.
code or standard." Other-vise the same requirements as ACI 318.
Limits pressure and tem-Allows 200*F for localized BVPS-2 complies perature of embedded piping areas. Allows 350' for with ACI 349 to 200 psi and 150*F.
accident or short term criteria.
periods. Allows 650*F for local areas from fluid jet from pipe failure.
Allows higher temperatures if supported by test results.
Requires vertical con-Requires all joints be BVPS-2 shows all joints-struction joints to be shown on plans or approved on plans and complies wetted and coated with by Engineer. All con-to ACI 349. In ad-neat cement grout before struction joints shall be dition, horizontal placing next lift.
wetted and standing water construction joints removed. Grout not required, are covered with a minimum 1/2 in, thick starter grout and vertical construction joints are coated with a thick-bodied cement water paste.
Chapter 7 The engineer may_ specify Tolerances on bar placenert BVPS-2 concrete tolerances. Placement liberalized to ACI 301 specification com-tolerances are stricter standards for menher sizes plies with ACI 301 than ACI 301.
used in the internals.
and is more conser-I Tolerances on minimum con-vative than ACI 349.
crete cover are larger than ACI 301.
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l Ttble 15.1 (Cont'd) j Regulatory Guide i.
Code 1.142 Section ACI 318-71 ACI 349-76 Rev. 1, Oct 1981 Justification
, Specifies minimum reinforce-Reinforcement shown erat for nuclear concrete
'on BVPS-2 drawings structures.
conforms to minimum requirements of ACI 349.
Requires welded splices or BVPS-2 requires that i
positive connections for splices and anchora-splicing load carrying rein-ges comply with ACI forcing bars located in 318 criteria. Since regions of membrane tension membrane tension normal to the splice, forces are not a sig-nificant factor for BVPS-2 structures, the intent of ACI 349 i
is met.
Chapter 8 Gives procedure for Eliminates Alternate Design Alternate Design Analysis and Alternate Design Nethod Method.
Method is not used Design General at BVPS-2.
Considerations Allows use of fillers Prohibits use of fillers in Fillers are not in concrete joist concrete joist construction.
used at BVPS-2.
l construction.
Chapter 9 Requires consideration of BVPS-2 practice is Strength and dynamic response of concrete in accordance with Serviceability
-structure, foundation, and ACI 349.
Requirements surroundaag sotl.
i, Regaires following load BVPS-2 combinations combinations applicable to are:
j the internals-5 of 8
Table 15.1 (Cont'd)
Regulatory Guide Code 1.142 Section ACI 318-71 ACI 349-76 Rev. 1, Oct 1981 Justification i
- 1. U = 1.4D + 1.7L 1.
U = 1.4D + 1.7L + 1.7Ro
- 1. U=0.75(1.4D+1.7CL)
- 2. U = 0.75 (I.4D + 1.7L +
2.
U = 1.4D + 1.7L +1.7Eo +
- 2. U = 1.4D + 1.7L +
- 2. U=1.4D+1.7L
.)
1.9E) 1.7Ro 1.9Eo + 1.7Ro
- 3. U=1.4D+1.7L+1.9Eo
.3. U = 0.9D + 1.43E 4.
U = D+L+To+Ro+Ess
- 4. U=0.9D+1.4Eo i
6.
U = D+L+7a+Ra+1.25Pa
- 6. U = D+L+Ta+Ra+1.5Pa
~[
- 5. U=1.00+1.0L+1.0Ess- !
7.
U = D+L+Ta+Ra+1.15Pa
- 7. U = D+L+Ta+Ra+1.25Pa
+1.0(YrtYj +Ym)
+1.0(Yr+Yj +Ym)+
- 6. U=0.9D+1.0Ess
+1.15Eo 1.25Eo
- 7. U=D+L+Ta+Ra+1.5Pa 8.
U = D+L+Ta+Ra+1.0Pa
[
+1.0(Yr+Yj +Ym)
- 8. U=D+L+Ta+Ra+
+1.0Ess 1.25Pa+1.0(Yr+
I Yj+Ym)+1.25Eo 9.
U = 1.05D+1.3L+1.05To
- 9. U = 1.05D+1.3L+1.3To r
+1.3Ro
+1.3Ro
- 9. U=D+L+Ta+Ra+
l Pa+1. 0(Yr+Yj +
- 10. U = 1.05D+1.3L+1.3Eo+
- 10. U = 1.05D+1.3L+1.4Eo Ym)+Ess i
1.057o+1.3Ro
+1.3To+1.3Ro i
The controlling BVPS-2 loads combi-
. [
nations are identical
[
to those of ACI 349 i
and Regulatory Guide I
1.142, therefore 1
BVPS-2 meets the in-tent of ACI 349 and I
,t l.,"
t.
j, 6 of 8
[
~
Tchle 15.1 (Cont'd)
L Regsletary Guide Code 1.142 Section
- I 318-71 ACI 349-76 R
Justification y. 1, Oct 1981 For combination 7 and 8 For combinations 7 and BVPS-2 cr.teria i
local strength can be 8 local strength can allow local stresses l
exceeded for Yr, Yj, and be exceeded if no loss to be exceeded if l
Yo, if no loss of safety-of function of any there is no loss of related system results.
safety-related struc-function of any l
tures systems or safety-related components.
system.
Chapter 10 Specifies minimum require-Reinforcement dis-Flexure and Axial ments for distribution of tribution exceeds Loads reinforcement in beams and minimum requirements i
one-way slabs.
for the internals structure.
i Chapter 11 Establishes punching shear BVPS-2 limits the Sheer and Torsion allowables for slabs and nominal permissible walls based on the ratio punching shear stress [
of the long side to short carried by concrete side of concentrated load to 4 Membrane or reaction area with tension forces are consideration given for not significant and presence of membrane aspect ratios are stresses.
usually 1.0.
Chaptcr 12 Requires testing of BVPS-2 tests for l
Development and mechanical connections.
mechanical con-
'[
Splices of nections are in Reinforcement accordance with ANSI /ASME N45.2.5-1978.
t Chaptcrs No significant changes.
13 thru 17 i
f 7 of 8 l
I I
I i
I Tchle 15.1 (Cont'd)
Regulatory Guide Code 1.142 j
Section ACI 318-71 ACI 349-76 Rev. 1, Oct 1981 Justification Chapter 18 There is no pre-Prestressed stressed concrete Concrete in BVPS-2 struc-tures.
Chapter 19 Applies only to thin shell Applies only to the design Not applicable to Shells concrete structures.
of shell concrete structures BVPS-2 structures, having thicknesses equal to or greater than 12 in.
ACI 349-80 Mot included in ACI 318.
BVPS-2 meets the Appendix A requirements of Thermal ACI 349.
l.
Considerations i
j ;?
ACI 349-80 Not included in ACI 318.
Sets permissible BVPS-2 meets the Appendix C ductility ratios requirements of Special Provisions ACI 349 and~
l' for Impulsive and Regulatory Guide l;
Impactive Forces 1.142.
II
!c
(
8 of 8
i NRC STRUCTURAL AUDIT ACTION ITEMS i
- 16. The applicant took some exceptions to the provisions of Regulatory Guides 1.10, 1.55, 1.69, 1.94, 1.115, 1.143.
Deviations from these Regulatory Guides should be identified and justified by the applicant.
Response
i BVPS-2 positions on Regulatory Guides 1.10, 1.55, 1.94, and 1.115, which identify and justify deviations from the guides, are presented in FSAR Table 1.8-1.
Positions on Regulatory Guides 1.69 and 1.143 are revised as'follows. These revisions to Table 1.8-1 will be included in a future FSAR amendment.
1 4
i i
1
.m
1 SVPS-2 FSAR f
TABLE 1.8-1 (Cont)
RG No. 1.69 Rev. O i
FSAR Reference Section 12.3.2 CONCRETE RADIATION SHIELDS FOR NUCLEAR POWER PLANTS (DECEMBER 1973) i Regulatory Guide 1.69 invokes the requirements and recommended
)
practices contained in ANSI N101.6-1972, " Concrete Radiation 1
Shields."
The design and construction procedures for Beaver Valley Fower Station - Unit 2 (BVPS-2) will meet or exceed the guidance of Regulatory Guide 1.69, with the following alternatives:
2 1.
ANSI N101.6-1972 requires that shop drawings be prepared showing details and dimensions of formwork, and then I
approved by the responsible engineer before fabrication of i
the formwork may begin. On BVPS-2. it is'the responsibility of field personnel to visually check all formwork. Detail j
drawings are made only for special applications.
l
{
2.
Finishing and patching of concrete surfaces after removal of l
j forms will conform to Chapter 9 of ACI-301 rather than f
Section 8.7.5 of ANSI N101.6.
It is not necessary to complete this work within 96 hours0.00111 days <br />0.0267 hours <br />1.587302e-4 weeks <br />3.6528e-5 months <br /> after the placing of concrete.
j 3.
Section 8.2.4 of ANSI N101.6 lists the maximum vertical drop i
of concrete as 5 feet.
The maximum vertical drop of j
concrete during placement operations is 6 feet. Experience l
I j
has indicated that suitable equipment and provisions are
(
given to prevent segregation of the concrete.
I I
J t
i l
i i
a k
i 4
i I
i 1
I l
i w
I BVPS-2 FSAR I
TABLE 1.8-1 (Cont)
RG No. 1.143. Rev. 1 FSAR Reference Sections 3.8.4, 10.4.8. 11.2, 11.3, 11.4, 11.5 DESIGN GUIDANCE FOR RADI0 ACTIVE WASTE M ANAGEMENT SYSTEMS. STRUCTURES.
AND COMPONENTS INSTALLED IN LIGHT-WATER-COOLED NUCLEAR POWER PLANTS (OCTOBER 1979)
Beaver Valley Power Station - Unit 2 meets the intent of Regulatory Guide 1.143 with the following alternatives:
Paragraph C.I.1.3 The steam generator blowdown flash tank is located in the turbine building, a nonseismic structure.
Leakage from steam generator blowdown system components located in the turbine building is collected in the turbine building sumps and monitored prior to release to the environment. The turbine building drain release will be automatically secured when the concentrations exceed the maximum permissible concentration (MPC).
Paragraph C.I.2.2 The steam generator blowdown flash tank relief valve discharges to the discharge structure. The structure drains are not capable of being processed by the liquid waste system.
Releases from the steam generator blowdown system flash tank re-lief valve are anticipated operational occurrences, which release activity to the environment at concentrations equal to or less than that of secondary steam.
Paragraph C.1.2.3 The steam generator blowdown evaporator test tanks and the steam generator blowdown flash tank do not have curbs or elevated thresholds.
i Test tanks receive distillate from the steam generator blowdown evaporators and provide facilities for storage and sampling prior to release to the environment. Calculations show that the tanks do not require shielding due to the low activity level of water expected in these tanks. A floor drain is pro-vided in the general area of the test tanks to collect leakage and overflow in the auxiliary building sump for pumping to the liquid waste system. Refer to paragraph C.1.1.3 for the steam generator blevdown flash tank.
BVFS-2 TSAR TABLE 1.8-1 (Cont)
Paragraph C.1.2.5 The refueling water storage tank is not provided with a dike or retention pond. Drains for the area adjacent to the structure are directed to the river via the storm drains. Tank overflew is directed to the liquid waste system via piping.
The refueling water storage tank is fabricated in accordance with the requirements of ASME Ill, Class 2.
The atmospheric tank is tested full of water to ensure that there are no leaks, and undergoes 100-percent radiographic examination on the shell. Tank overflow is directed to the liquid waste system via the safeguards building sump piping. The radio-nuclide concentrations of the refueling water storage tank liquid will be determined following each refueling. When the concentrations exceed HPC, periodic surveillance of the tank area will be used to identify any leakage from valves and fittings. This will ensure minimal discharge of radioactive effluent to the storm drain system and subse-quantly to the environment.
Paragraph C.2.1.1 The gaseous vaste system equipment meets or exceeds the codes in Table 1.
The gaseous waste delay beds, gaseous waste surge tank, waste gas chiller, overhead gas compressors. piping and valves are designed and fabricated to ASME !!!.
The gaseous waste storage tanks are designed and, fabricated to A$ME VI!!,
Division 1.
All equipment manufacturing codes exceed those npocified by Table 1 of Regulatory Guide 1.143.
Paragraph C.4.3 The piping downstream of the overhead gas compressors is one balf in.ch.
The discharge piping for the overhead gas compressors is designed to not impose any unnecessary pressure loss in that portion of the gaseous wasta system.
l l
BVPS-2 FSAR l
TABLE 1.8-1 (Cont) l I
l Paragraph C 5.1.1 l
Beaver Valley Power Station - Unit 2 (BVPS-2) does not apply the Regulatory Culde 1.60 des ign ground res po ns e s pe ct ra.
Insteal, a BVPS spectrum is applied as described In Sectlon 3.7B.1.
I Paragraph C.5.2.1 Beaver Valley Power Station - Unit 2 does not use Regulatoy Culde 1.60 s pe ct ra nor Regulatory Culde 1.61 damping values.
- Insteal, refe r to Sect lons 3.78.1.1 am! 3.78.1.3.
Paragraph C.S.2.2 Beaver Valley Power Statlon - Un(t 2 compiles wlth this sect ion,
except that the s pe ct ra ref e renced in Paragraph C.5.2.1 is used.
Refer to Sect ions 3.78.1 an! 3.7 B.2.
Paragraph C.S.2.3 Beaver Valley Power Station - Unit 2 uses the modal t ime-h is to ry t echnlque to generate floor res pons e s pe c t r a.
Refer to Sectlon 3.7B.2.
Paragraph C.5.2.4 Beaver Valley Power Statlon - Unit 2 uses ACI-318-71.
This was the code in ef fect at the t ime of de s ign.
Any dif ferences between Act 318-71 and ACI 318-7 7 are conaldered to be Ins igni fic ant.
Paragraph C.6 Quality assurance programs used for the manufacture of the equipment l
u sed in the radweste management systems are in accordance with the l
c ode s and s t and a rd s s pe c i fi ed in the eq ui pme nt pur ch as e s peci fica t ions.
1 I
i i
NRC STRUCTURAL AUDIT ACTION ITFJIS
- 21. With respect to the issue of the rate of pressure drop for tornado definition, please provide a quantitative technical justification demonstrating that the intent of Regulatory Guide 1.76 is fully met.
Also, address the adequacy of using a single degree of freedom modeling in assessing the structural response of a plate subject to the above indicated pressure drop loading.
Response
The nonlinear pressure drop profile specified in Section 3.3.2.1 of the BVPS-2 FSAR is identical to the pressure drop profile resulting from the tornado wind model specified in WASH-1300. As stated in Regulatory Guide 1.76, the values for the design basis tornado characteristics are taken from the WASH-1300 document.
Therefore, the pressure drop profile specified for BVPS-2 clearly meets the intent of Regulatory Guide 1.76.
The dynamic load factors for a series of single-degree-of-freedom systems, subjected to the pressure drop time history (Figure 21.1),
were determined.
The resulting DLF's were compared (Figure 21.2) to those resulting from the linear pressure drop profile (Figure 21.1) suggested in NRC Question 451.2.
A review of the Category I structures was performed to determine the wall or roof panel that would have the lowest natural frequency when modelled as a single-degree-of-freedom dynamic system.
The review determined that the lowest resulting natural frequency is approximately 9.0 cps.
It is seen from Figure 21.2 that for systems with natural frequencies greater than 4 cps the resulting DLF's are essentially the same for both pressure drop profiles.
Therefore, since the lowest natural frequency of any panel, (9 cps), is significantly above 4 cps, either profile will result in the same equivalent pressure load. Thus, it can be concluded that the intent of Regulatory Guide 1.76 has been met.
The panels can be adequately modelled as single-degree-of-freedom systems based on the procedures presented in Biggs (1964) because the loading is nonfluctuating in nature and is applied uniformly over the surface of the panel.
References:
1.
WASH-1300. " Technical Basis for Interim Regional Tornado Criteria," (UC-11) USAEC, Washington, D.C.
2.
Biggs, John M.
1964. " Introduction to Structural Dynamics," McGraw Hill Book Company.
3 Sv&GEsTf.o u s car. egopius s.
v l
10 _ _
Oa O
2.0 6VPS Z FAoF4r w
Qt D
10
/
\\
ul
\\'
40 i
Go 10 X,0 3.0 4.0 5.o G.O TIME (secon d s)
FIGURE I
i I
)
of 2.0 -
a U
- f Q
l G, l
Rt4UL1 0F SU66fSTED LlHtAR N098LL
\\
- l. +.,\\
Rtsuus or syps.2 punortus O
l' i
j
/*l -
t /\\
JL s
k,M
^
.a m
=%
f, o
/.c 20 J,o 4.0
- 1. 0 4,, o j
FR EQ UEu t.N (ces)
PGURE 2
Figures 21.1 and 21.2 Pressure Drop and Dynamic Load Factor Beaver Valley Power Station Unit 2
I NRC STRUCTURAI, AUDIT ACTION ITEMS
- 22. Evaluate the (11) Category I tanks with respect to the criteria of SRP Section 3.8.4 in order to demonstrate their design adequacy.
The evaluation should consider the following parameters i
I 1.
Use realistic modeling of the tanks, accounting for the flexibility of the tanks.
2.
Consider any surrounding soil embedment as well as pipe anchoring load effects.
3.
Consider both sloshing and overturning effects.
4.
Evaluate the adequacy of the tanks against buckling failure.
5.
Ensure that foundations, anchoring bolts, and other con-nections to the tanks are adequately designed.
For any deviations from the above SRP Section 3.8.4 criteria, use as-built material strength, applicable test.results, and design con-servatisms to justify the deviations.
Response
1.
The eleven Category I tanks were designed in accordance with ASME III Subsection NC for the Class 2 tanks and Subsection ND for the Class 3 tanks.
l The effects of tank wall flexibility have recently been addressed i
using Housner's deformable tank wall model (Haroun and Housner 1981).
This procedure assumes the hydrodynamic pressures developed in ground-supported tanks during an earthquake is defined by the combination of a long-period convective component (related to sloshing), a short period flexible component which is caused by the vibration of the tank walls,. and a rigid liquid pressure component which moves simultaneously with the horizontal acceleration at the base of the tank.
The two large relatively thin-walled tanks (refueling water storage tank and the primary domineralised water storage tank) with low fundamental impulsive frequencies had sufficient margin in the existing design so that the increased loads due to wall flexibility could be sustained. The remaining nine smaller dia-meter relatively thick-walled tanks had fundamental impulsive frequencies where spectral accelerations in the rigid range apply.
In this frequency range, tank wall flexibility analysis is not required.
2.
Ten of the eleven tanks are above ground so the surroundir,s soil embedment is not applicable.
The one buried tank (fuel oil day tank) is encased in concrete.
Pipe anchoring load effects for either the buried or above ground piping have been factored into the designs.
==wm.-
r
+..
6
NRC STRUCTURAL AUDIT ACTION ITEMS 3.
For the ref ueling water storage tank and the primary deminer-alized water storage tank, overturning moments and base shears computed by combining the sloshing mode with the flexible were mode and rigid mass mode as described in Item 1 above.
Sloshing ef fect s (U.S. Atomic Energy Commission 1963) were also conside red in the anal ys is of the boric acid tank and que nch spray chemical ad dition tank to determine overturning moment s and base she ars.
Sloshing ef fect s were not cons ide red for the remaining seven tanks which are either horizontally mounted or relat ively slende r tanks, and, therefore, little or no mass participates in the sloshing mode.
4.
Buckling failure has be en ad dr es sed in the analyses of the refueling water storage tank and the primary demineralized water sto rage tank, which are large fla t-b ot tomed t ank s.
The designs of these tanks are such that the cm pr es sive s tr es se s are le s s than the al lowab le com pres sive s tr es s (based on the allowable com pr es sive stresses of NC/ND 3133.6 increased in accordance with Table NC/ND 3821.5-1).
Tank wall buckling is not cons ide red a credible failure mode fo r the remaining nine tanks due to their geometry (relatively small diameter thick-walled tanks) with spectral accelerations in the rigid range.
5.
The design of the foundat ions is in accordance with ACI guide-lines as specified in Sect ion 3.8.5.
Anchor bolt s and other connect ions are de s igned within the al lowab le limits of the AISC code as specified in Section 3.8.4.
References 1.
liaroun, M.
A.
a nd flo u sn e r, G.
W.
1981.
" Seismic Design of Liquid Storage Tanks," Journal of Technical Counells of ASCE, April 1981.
2.
U.S.
Atomic Energy Commission 1963.
" Nucle ar Reactors an! Earth-quakes," TID-7024, Washington, D.C.
3.
- Coates, D.
W.
" Rec omme nd ed Revis ions to Nuc le ar Regulato ry Com-mis sion Seismic Des ign Criteria CR 1161, Lawrence Live rmo re Laboratory.
NRC STRUCTURAL AUDIT ACTION ITEMS l
- 24. Perfore a simplified stick model dynamic analysis of the cable tunnel accounting for the overburden and embedeent effects. Demonstrate that i
the provisions of SRP Section 3.8.4 are met.
For any deviations from the SRP criteria identified provide a justification considering the j
as-built material strength and conservatises.
Also, account for any
)
significant relative ground motions upon the tunnel seismic responses.
1 1
Response
The original soil-structure model was modified and reanalysed to further consider embedeent and overburden effects on the cable tunnel.
i l
The originsi structure model consisted of two lumped masses (6 degrees-of-freedos per mass) interconnected by a weightless elastic been j'
member. The lumped masses represent the floor and roof slabs plus the 1
walls in between.
The elastic beam member represents the stiffness characteristics of the wall system.
The. founding material (soil) was i,
modeled as elastic springs, based on elastic half-space theory (FSAR Section 3.78.2).
The original model was modified as follows:
l 1.
Overburden was accounted for by increasing the mass properties at the roof elevation.
i 2.
Embedeent was accounted for by modifying the elastic half-space soil springs by the correction factors developed by Kausel and Roesset (1975) and Kausel, W itman, et al. (1978).
Analyses of the modified soil-structure model show that the fundamental i
i frequency has increased by approximately 13 percent.
This frequency t
j change is within the limits of peak widening of the amplified response spectra used at BVPS-2 (+25 percent and -20 percent based on period).
The structural acceleration and displacenest values from the reanalysis i
are lower than those used in the design of the cable tunnel. Thus the i
design is based on conservative results.
I f
i To address the effect of relative ground motions upon the cable tunnel
[
design, an analysis was performed to determine the stresses resulting in the structure from relative ground displacements. This analysis was l
i l
based on Kausel (1969), Neweerk (1971), and Neweerk and Rosenblueth t
(1971).
It was assumed that the motion of the tunnel was the same as i
i that of the surrounding soil.
The resulting stresses are within the elastic limits for both axial and bending strains due to relative ground motions.
References 1.
Kausel, E.
and Roesset, J. M. 1975. " Dynamic Stiffness of Circular Foundations," Journal of the Engineering Mechanics Division, ASCE, December 1975.
t 8
5
NRC STRUCTURAL AUDIT ACTION ITEMS 2.
- Kausel, E.,
- Whitman, R.
V.,
et al. 1978. "The Spring Method for Embedded Foundations," Nuclear Engineering and Design 48 (1978),
North-Holland Publishing Company, 1
3.
Kausel, T. R.1969. " Earthquake Design Criteria for Subways" Journal of the Structural Division, ASCE, June 1969.
4.
- Neweark, N.
M.
1971.
" Earthquake Response Analysis of Reactor Structures," Nuclear Engineering Design 20 (1972), North-No11and Publishing Company, November 8,1971.
5.
Neweerk, N. M. and Rosenblueth, E.
1971. " Fundamentals of Earthquake Engineering," Prentice Hall, Incorporated.
}
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s
NRC STRUCTURAI, AUDIT ACTION ITD1S
- 28. Please provide a simplified justification to demonstrate that T ap-plicable to the cubicles in the containment need not be included is the l
design.
1 Responset l
The BVPS 2 FSAR specifies in Section 3.8.3.3 loading combinations for l
design of the reactor containment interior concrete structures.
It is stated therein that accident loads considered in the loading com-binations control design of the internal concrete structures.
1 1
These accident loads are dynamic and decrease in magnitude with time.
l For the design of the cubicles peak values of P,
R,, Yj, lues within Y, and Y, r
l are applied simultaneously as they reach their maximum va fractions of a second af ter initiation of an accident. This is demon =
l strated on Figure 28.1 for the pressure loading Pa.
The temperature contrib is considered in the cubicle design with these loads but its term T ution to the state of stress at this early, but governing, time is insignificant.
A plot of the temperature T" cles for the ambient air conditions inside and i
immediately outside the cubi is presented on Figure 28.2.
It is noted here that within 20 seconds after initiation of the accident, the ambient air temperatures inside and outside of the cubicle are identifica1.
This will lead to symmetric thermal stress without bending in the walls and floor slabs of the cubicles.
With time and this uniform temperature throughout the containment internals, stress-free thermal growth will occur.
Because of the presence of the other early time dynamic accident loads the evaluation of stresses due to T.
immediately following the accident must be evaluated.
A thermal analysis was performed to evaluate the resulting thermal gradien't through the concrete wall / floor slab which conservatively considers ti.e concrete surface temperature to be equal to that of the ambient mir temperature. The analysis is based upon a thermal transient (Figure 28.3) applied to the inside surface of the crane wall which reaches a higher peak (350 'F) than the actual BVPS 2 transient for 7 Although this transient reaches a higher peak it can still be u, sed to demonstrate the 7, temperature profile through the concrete as a function of time (Figure 28.4). The depth of significant temperature penetration within the first 20 seconds is only a fraction of an inch.
The maximum compressive thermal strain can be conservatively estimated ast l
l sthermat - an l
\\
4 L.
t NRC STRUCTURAL AUDIT ACTION ITEMS l
l Where a
= 5.5 x 10*8 in./in./'T l
l l
AT
= T - T,,g T
= maximum concrete temperature (275'F)
T,,g a stress free temperature (70*F) 8 l
thermal
- 0.001 < " concrete allowable = 0.003 The results of this analysis demonstrate that the effects of Ta are of I
minor importance in the design of the cubicles, compared to the other Aoverning accident loads.
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03 :recuo s, 345 21 le (,if, Figure 28.4 Sunury of Thermal Analysis Beaver Valley Power Station -
Unit 2
NRC STRUCTURA!. AUDIT ACTION ITE!!S The following responses are provided in consideration of the Structural Engineering Section's comments on BVPS-2 Standard Review Plan differences contained in the NRC letter dated September 22, 1983.
- l SRP Sections With respect to the definition of wind loading, the 3.3.1.!!.3 i
Beaver Valley 2 plant referred to ASCE Paper No. 3269 i
for derivation of wind pressure on structures.
The pertinent SRP Section 3.3.1 Revision 2, however, con-siders the ANSI A 58.1 code as the acceptable base document for defining wind loads.
The applicant should demonstrate that the wind load definition and procedurcs from ASCE Paper No. 3269 are 1
as conservative as those of the ANSI A 58.1 code.
J Re_sponse For a fastest mile wind speed 30 ft above ground of 80 mph (FSAR Section 3.3.1.1),
the effective velocity pressures determined in accordance with ASCE Paper No. 3269, which are used for BVPS 2, are comparable to those required by ANSI A58.1-1972.
Figure 1 shows the values f rom ANS! 58.1, Table 5, Exposure C as well as those used for BVPS 2.
]
As can be seen, the BVPS 2 velocity pressures for structures up to i
50 ft wide (measured perpendicular to wind direction) exceed ANSI A58.1 pressures in all cases.
For structures 50 to 100 ft wide, BVPS 2 exceeds ANSI A58.1 except for an insignificant band from approximately 42 to 50 f t above ground.
For structures 100 to 150 f t wide, BVPS-2
)
exceeds ANSI A58.1 except for minor bands from 30 to 50, 100 to 150, i
and 360 tn 400 f t above ground. The BVPS 2 pressures for structures I
greater than 150 f t wide are generally less than those of ANSI A58.1.
l tt, address structures greater than 150 f t wide, where BVPS 2 velocity pressure is less than ANSI A58.1, a review has been performed for the service building, considering a wind in the north south direction. The service building is 186 ft wide and 70 ft hiah (FSAR Section 3.8.4.1.7).
The review was performed by determining the velocity 1
pressure in accordance with the procedure given in ANSI A58.1, Appendix A6.3.4.1.
(If used for structures of lesser width, this procedure would not alter the comparison made above.)
This procedure applies a
" dynamic approach to the action of wind gusts." Using this procedure, the resultina velocity pressures, up to the building height, are approximately 10 percent less than those niven in ANSI A58.1, Table 5, i
Exposure C (rigurc 3.3.1.11.1-1). Also, these velocity pressures are within approximately 10 percent of the BVPS 2 pressures.
Therefore, while there is a dif ference in the manner in which building response to wind gusts is considered by ANSI A58.1 and ASCE Paper No.
3269, there is no significant ditference between the wind velocity
NRC STRUCTURAL AUDIT ACTION ITEMS 1
pressures used for BVPS-2 and those determined in accordance with ANSI A58.1-1972.
For parts and portions of buildings and structures, ANSI A58.1 requires that greater velocity pressures be postulated for tributary areas of less than 1000 sq ft.
Larger pressure coefficients are required to be applied at corners, ridges, eaves, etc. These are intended to provide adequate margin in the design of conventional exterior sheathing to resist localized wind loads. The exter.ior panels of seismic Category I structures at BVPS-2 are characteristically reinforced concrete 24-inches thick. These exterior panels are adequate to withstand' local wind loads within the. structural acceptance criteria for load combinations that include wind load.
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NRC STRUCTURAL AUDIT ACTION ITEMS SRP Section:
The SRP specifies that closely spaced modes be combined 3.7.3.II.7 in accordance with Regulatory Guide 1.92.
The applicant stated that the Westinghouse methods were used for combining closely spaced modes.
The applicant should provide technical data to show the equivalency of the above two approaches or justify the deviation.
Response
The method of combining closely spaced modes for items within SWEC's scope is in accordance with Regulatory Guide 1.92, Rev. 1, dated February 1976.
Westinghouse, when combining closely spaced modes, used an alternative method to those endorsed by Regulatory Guide 1.92, Rev. 1.
The Westinghouse " Epsilon Factor" method, which is described in FSAR Section 3.7N.2.7, has been used only for items supplied and qualified by Westinghouse.
This method has previously been revived by the NRC during Mechanical Engineering Branch reviews on the Seabrook, Shearon Harris, Comanche Peak, Catawba, and SNUPPS plants.
The staff has accepted the " Epsilon Factor" method.
-