ML20044D788
| ML20044D788 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 05/17/1993 |
| From: | Denton R BALTIMORE GAS & ELECTRIC CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| TAC-M85222, TAC-M85223, NUDOCS 9305200291 | |
| Download: ML20044D788 (22) | |
Text
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6 BALTIMORE GAS AND I
ELECTRIC -
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1650 CALVERT CLIFFS PARKWAY LUSBY, MARYLAND 20657-4702 l
l ROBERT E. DENTON l
VicE PRE 51 DENT h
NUCLEAR ENERGY l
(4eo) eso-eass 3-l i
U. S. Nuclear Regulatory Commission l
Washington,DC 20555 ATTENTION:
Document Control Desk l
SUBJECT:
Calvert Cliffs Nuclear Power Plant Unit Nos.1 & 2; Docket Nos. 50-317 & 50-318 Response to Request for Additional Information - Civil Engineering Design l
Report (TAC Nos. M85222 and M85223)
REFERENCES:
(a)
Letter from Mr. R. E. Denton (BG&E) to NRC Document Control i
Desk, dated April 21,1993, same subject t
(b)-
Letter from Mr. R. E. Denton (BG&E) to NRC Document Control
{
Desk, dated May 7,1993, Response to the Station Blackout Rule Gentlemen:
In the referenced letter we advised you that we would provide the responses to Questions 1,6 and 7b separately. Attached are these responses. Additionally, we are providing Figures 3-47 through 3-58 j
of the Civil Engineering Design Report. We had also committed to provide information concerning i
the effect of turbine missiles on the Diesel Generator Building. Because of the change in the scope of the project (Reference b), we have moved the safety-related building out of the path of a postulated turbine missile. Therefore, in accordance with Regulatory Guide 1.115, turbine missiles no longer have to be considered as a hazard for the Diesel Generator Buildings.
Should you have any further questions regarding this matter, we will be pleased to discuss them with i
you.
j Very truly yours,
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w 2(10024 for R. E. Denton Vice President - Nuclear Energy
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RED / PSF / psf / dim g
t) hN Attachment 9305200291 930517 i
PDR ADOCK 05000317 P
PDR g lol
Document Control Desk May 17,1993 Page 2 cc:
D. A. Brune, Esquire J. E. Silberg, Esquire R. A. Capra, NRC
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D. G. Mcdonald, Jr., NRC T.T. Martin, NRC P. R. Wilson, NRC R. I. McLean, DNR i
J. H. Walter, PSC
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RESPONSE TO CIVIL ENGINEERING AND GEOSCIENCES BRANCH REQUEST FOR l
ADDITIONAL INFORMATION Qpestion 1:
In Section 2.3.2 it is stated that the dynamic earth pressures due to seismic ground acceleration l
were calculated by the method proposed by Seed and Whitman in 1970 which deals with earth l
retaming structures capable of movement. Justify the use of their method for the basement walls l
of the Diesel Generator Buildings which are rigid and do not undergo sufficient movement as required in their method.
Resnonse to Question 1:
I He Mononobe-Okabe method described in Seed and Whitman (Reference 1) was developed to determine dynamic lateral earth pressures on retaming structures, and assumes that the wall yields sufficiently to produce a minimum active pressure. In deriving the dynamic lateral earth pressures for the Diesel Generator Building, it is recognized that the actual pressure will be greater than for the active case due to the non-yielding nature of the rigid wall.
In his presentation summarizing the advance in the state of the art on seismic forces on gravity retaming walls, Whitman (Reference 2) briefly discusses non-yielding walls and notes that l
increases over the computed active pressures have been reported from both a theoretical approach and frma model tests. In consideration of non-yielding conditions, such as the embedded walls of a massive structure, a factor of 2. is applied to all of the dynamic forces developed using the i
Mononobe-Okabe method. 'Ihis value is based on the findings of Wood (Reference 3) and on j
the fact that the magnitude of at rest pressures are approximately twice the magnitude of active pressures.
He backfill specified and used for the Diesel Generator Building is a highly compacted, well-l graded crushed stone, with a 4 angle that can be conservatively estimated as 42*. Using the Mononobe-Okabe method and a preliminary backfill unit weight of 130 pef, the resulting pressure computed against the top of the wall of height 'H' feet is approximately 11H psf. Applying a factor of 2 for non-yielding walls, the resulting pressure at the top of the wall is approximately 22H psf. This produces a triangular pressure distribution which linearly decreases to zero at the base of the wall.
Unit weights will be validated by backfill placement control testing performed at thejobsite. Any differences between test information and preliminary values assumed in the design will be accounted for in the final building design.
In Revision 1 of the Civil Engineering Design Report, Section 2.3.2 will be clarified as follows:
The dynamic earth pressures due to the soil were first calculated by the l
Mononobe-Okabe method outlined by H.B. Seed and R.V. Whitman in Reference 29, using a maximum acceleration of 0.15 g. In consideratian of the non-yielding conditions i
of rigid walls, such as the embedded walls of a massive structure, a factor of 2 is applied to all of the dynamic forces developed using the Mononobe-Okabe method."
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am
Question 6:
On page 3-16, in the second paragraph from the top, it is indicated that there is separation baween the buildings which is provided by a gap of approximately three inches such that physical contact between buildings does not occur during earthquakes. Because of this narrow gap of separation, there may be structure-structure interaction. Indicate if this condition is taken into consideration and what the effect is. In mentioning the three inch gap described above, has the effect of the differential settlement between the ends of the buildings been taken into account?
Response to Ouestion 6:
he scope of work has been revised to replace the second Category I building with a non-Category I building. The design of the non-Category I building is on hold at this time. In j
establishing the separation requirements between the two buildings, the effect of differential settlement of each building will be taken into account along with the seismic displacements and the thermal expansbn of the buildings. Once the decision is made regarding the design of the non-Category I building, the acceptance criteria of Standard Review Plan Section 3.7.2 for the interaction of non-Category I structures with Category I structures will be met by designing the non-Category I structures to satisfy one of the three following requirements given in the SRP:
a)
The collapse of any non-Category I structure will not cause the non-Category I stmeture to strike a seismic Category I structure or component.
b) he collapse of any non-Category I structure will not impair the integrity of seismic Category I structures or components.
c)
The non-Category I structures will be analyzed and designed to prevent their failure under SSE conditions in a manner such that the margin of safety of these structures is equivalent to that of Category I structures.
Although the seismic gap between the Category I and the non-Category I buildings may be narrow, the difference in mass between the two buildings will minimize structure-to-structure interaction. Since the non-Category I building will be lighter than the Category I building, the effect of the non-Category I building on the dynamic response of the Category I building will be insignificant. This position is supported by Conclusion No. 4 of Reference 4.
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i Ouestion 7:
)
For Figure 3-46 of the Civil Engineering Report:
l a.
Provide the masses and spring constants which represent the structural elements i
and components as shown in the figure.
b.
Nso indicate which relationships for shear modulus and damping variations with strain are used in your analysis.
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Resnonse to Ouestion 7:
a.
The response to this portion of the question was provided to the NRC in a previous submittal.
b.
Section 3.7.2 (II.4) of the Standard Review Plan (SRP) states that d.sta obtained during recent earthquakes "seem to show that there may not be a decrease in (soil) shear modulus or (an) increase in (soil) damping under (the) high strains" induced during earthquakes. During a meeting held with the NRC on May 5,1992, the NRC recommended that the shear modulus reduction and damping curves defined in Reference 5 be considered when establishing the curves for use in the seismic analysis. He NRC recommended curves, which were obtained from References 6 and 7, are applicable to sand and clay and when compared to curves typically used by industry:
Reflect less of a reduction in shear modulus Less of an increase in damping While the curves from Reference 5 were not used exclusively, they were, as noted below, considered when establishing the curves to be used to characterize the soil.
4 SAND l
Shear Modulus Reduction Curve The shear modulus reduction curve defined in Reference 5 coincides with the upper bound curve j
from Figure 7 of Reference 6. As noted in Reference 5, this curve was utilized in evaluations of several soft soil sites in the San Francisco area. Reference 8 indicates that the shear modulus versus shear strain values defined in Figure 7 of Reference 6 " fall within a relatively narrow band" and recommends using the average values within this band to characterize sand in seismic analyses. Dese average values, which are summarized in Table 7-9 (attached) and plotted in Figure 3-72 of the Civil Engineering Design Report, were chosen to represent the generally dense j
sands underlying the Diesel Generator Building site.
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l Damnine Curve ne data points used to define the damping curves for sand are summarized in Table 7-9 (2nrhed). Rese data points, which are plotted in Figure 3-74 of the Civil Engineering Design Report, were obtained from Reference 5 and correspond to the lower bound curve defined for sand in Figure 10 of Reference 6. He lower bound damping curve was used because of the relatively wide range in damping depicted in Figure 10 of Reference 6 and because the use of the lower bound damping values is conservative.
1 CRUSHED STONT Shear Modulus Reduction Curve l
l The data points used to define the shear modulus reduction curve for crushed stone are summarized in Table 7-10 (attached). These data points, which are plotted in Figure 3-73 of the l
Civil Engineering Design Report, coincide with the average curve for gravelly soils from Figure 14 of Reference 8. It should be noted that Reference 5 does not define a shear modulus reduction curve for crushed stone.
Damninc Curve The data points used to define the damping curve for crushed stone are summarized in Table 7-10 (attached). These data points, which are plotted in Figure 3-75 of the Civil Engineering Design Report, coincide with the curve defined in Figure 16 of Reference 8 for gravelly soils compacted at or close to a relative density of 80 percent. It should be noted that Reference 5 does not define a damping curve for crushed stone.
CLAY Shear Modulus Reduction Curve Reference 5 recommends using shear modulus reduction values for clay as defined in Reference 7.
These values are a function of the plasticity index (PI) of the clay, and are therefore site dependent. Two field investigations were conducted, one in 1980 and 1981 and a second in 1992, which assessed the geotechnical conditions at the proposed site of the Diesel Generator Building.
These investigations indicate the PI of the clay at the site is approximately 25. Consequently, the shear modulus reduction values used to characterize clay in the seismic analysis corresponds to the average curve for clay with a PI of between 2.0 and 40, as obtained from Figure 15 of Reference 7. He data points corresponding to the average curve are summarized in Table 7-11 (attached) and plotted in Figure 3-71 of the Civil Engineering Design Report.
Damninc Curve The data points used to defm' e the damping curve for clay are summarized in Table 7-11 (attached). Rese data points are the sarre as the points defined for sand above.
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TABLE 7-9 SAND SHEAR MODULUS REDUCTION AND DAMPING CURVES Effective Strain Shear Modulus Damping
(%)
Reduction Curve" 8)
Curvem 2) 0.0001 1.0 0.24 I
0.000316 1.0 0.42 0.001 0.97 0.8 0.00316 0.89 1.4 0.01 0.74 2.8 0.0316 0.53 5.1 0.1 0.29 9.8 0.316 0.13 15.5 1.0 0.05 21.0 3.16 0.05 21.0 10.0 0.05 21.0 Notes-(1)
These data correspond to the average curve for sands as defined in Figure 7 of Reference 6.
(2)
Reference 5.
t l
l 5
4
---+-mp-
TABLE 7-10 CRUSHED STONE SHEAR MODULUS RFnUCTION AND DAMPING CURVES Effective Strain Shear Modulus Damping
(%)
Reduction Curve ** 3)
Curve = 2) m 0.0001 1.0 0.34 0.000316 0.%
0.6 0.001 0.86 1.1 0.00316 0.72 2.0 0.01 0.54 6.0 0.0316 0.38 9.3 0.1 0.2 13.3-0.316 0.1 18.0 1.0 0.05 24.0 3.16 0.05 24.0 10.0 0.05
'24.0 Esim:
i (1)
These data correspond to the average curve for gravelly soils as defined in Figure 14 of Reference 8.
i (2)
These data correspond to the values established for gravelly soils at or close to a relative density of 80 percent as defined in Figure 16 of Reference 8.
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IABLE 7-11 1
CLAY SHEAR MODULUS RFnUCTION AND DAMPING CURVES Effective Strain Shear Modulus Damping
(%)
Reduction Curve
- O Curvema. 2) 0.0001 1.0 0.24 1
0.000316 1.0 0.42 0.001 0.99 0.8 0.00316 0.97 1.4 0.01 0.90 2.8 i
0.0316 0.76 5.1 0.1 0.53 9.8 0.316 0.29 15.5 1.0 0.14 21.0 3.16 0.06 21.0 10.0 0.96 21.0 Notes:
(1)
These data correspond to the average curve for clays with a plasticity index between 20 and 40 as defined in Figure 15 of Reference 7.
(2)
Reference 5.
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f e
i REFERENCES e
ti 1.
Seed, H. B. and Whitman, R. V. Design ofEank Retaining StructuresforDynamic Loads.
l ASCE Specialty Conference: Lateral Stresses and Earth-Retaining Structures. Cornell j
University. June 1970.
j i
2.
Whitman, R. V. Seismic Design and Beluwior of Gravity Retaining Walls. Lambe, P. C.
and Hansen, L. A. (eds.). Design and Perfonnance ofEank Retaining Structures, Georachnical Special Publication No. 25. New York, New York. American Society of Civil Engineers. pp. 817-842.
3.
Wood, I. H. Earthquake-induced 500 Pressures on Structures (Repon No. EERL 73-05).
l California Institute of Technology, Pasadena. 1973.
4.
Gantayat, A. N., Kamil, H., Kost, G., Krutzik, N. and Rutherford, D. H. Inwstigation of
}
l the injiuence ofinteraction ofIko Adjacent Structures on 1 heir Responses. Jaeger, T. A.
l i
. and Boley, B. A. (eds.). Transactions of the 5th laternational Conference on Structural Mechanics in Reaaor Technology. Volume K.(a). Holland. North Holland Publishing i
Company. 1979 K 6/8, pp.1-8.
l 5
Idriss, I.M. Response ofSop Soil Sites During Eanhquakes. Seed Memorial Symposium.
i 1990.
6.
Seed, H. B. and Idriss, I. M. Soll Modull and Dan; ping Factorsfor Dynamic Response.
l Analysis (Repon No. UG/EERC-70/10). December 1970.
?
7.
Sun,3. I., Golesorkhi, R. and Seed, H. B. Dynamic Modull and Dangping Ratiosfor i
Cohestw Soils (Repon No. UCB/EERC - 88/15). August 1988.
8.
Seed, H. B., Wong, R. T., Idriss, I. M. and Tokimatsu, K. Moduli and Damping Factors forDynamic Analyses of Cohesionless Soils, ASCE Journal of Geotechnical Engineering, November 1986.
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FIGURE 3-47 STRUCTURAL RESPONSE BUILDING ENCIDSURE N-S ACCELERATIONS
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El. 103.5' 0.161, 0.299 I
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66.5' 0.240 t
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Acceleration (g) i l
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I FIGURE 3-48 STRUCTLTAL RESPONSE BUILDING ENCLOSURE E W ACCELERATIONS t
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l Wall & Base Slab Elevated Slab Acceleration (g)
Acceleration (g)
I FIGURE 3-49 STRUCTURAL RESPONSE BUILDING ENCLOSURE VERT. ACCELERATIONS i
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Shear Force (x 10 k) l FIGURE 3-50 STRUCTURAL RESPONSE BUILDING ENCIDSURE N-S SIIEAR FORCFS l
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Shear Force (x 10 k) l FIGURE 3-51 STRUCTURAL RESPONSE BUILDING ENCLOSURE F W SHEAR FDRCES l
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FIGURE 3-52 STRUCTURAL RESPONSE BUILDING ENCLOSURE VERTICAL SIIEAR FORCES i
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50 100 150 200 3
Bending Moment (x 10 k-ft) l FIGURE 3-53 STRUCTURAL RESPONSE BUILDING ENCLOSURE N-S BENDING MOMENTS
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0 50 100 150 200 3
Bending Moment (x 10 k-ft) i FIGURE 3-54 STRUCTURAL RESPONSE i
BUILDING ENCLOSURE E-W BENDING MOMENTS i
~ ~ -
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Torque (x 10 k-ft) 3 i
FIGURE 3-55 STRUCTURAL RESPONSE BUILDING ENCLOSURE TORQUES i
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OBE SSE 0.227 0.457 El. 103. 5 ' --
i 0.167 0.341 El. 80.5' 0.13 0.270 El. 66.5' I
l El. 45.5' 0.122 El. 35.5' 0.056 i
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0.0 0.25 0.50 0.75 1.00 l
Displacement (in) l l
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l FIGURE 3-56 STRUCTURAL RESPONSE BUILDING ENCLOSURE N-S DISPLACEMENTS l
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0.140 0.286 l
El. 103.5' l
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.091 0.187 l
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I Displacement (in) l h
i FIGURE 3-57 STRUCTURAL RESPONSE
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BUILDING ENCLOSURE E-W DISPLACEMENTS
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O.0 0.25 0.50 0.75 1.00 Displacement (in)
Walls and Base Slab i
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BUILDING ENCLOSURE VERTICAL DISPLACEMENTS e
y m
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