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REVIEW 0F THE SEISMIC DESIGN CRITERIA FOR THE BEAVER VALLEY POWER STATION (Docket No. 50-334)
Revised April 10, 1970 JOHN A. BLUME & ASSOCIATES, ENGINEERS San Francisco, California 8508130030 850703 1 **
.L v D 0 HERRMAN85-301 PDR
REVIEW OF THE 5,EISHIC DESIGN CRITERIA FOR THE BEAVER VALLEY POWER STATION (Docket No. 50-334)
This report summarizes our review of the eng1'neering factors pertinent to the seismic and structural adequacy of the Beaver Valley Poaer Station.
The plant will be located in Shippingport' Borough, Beaver County, Pennsyl-vania on the south bank of the Ohio River approximately one mile from '
Midland, Pennsylvania.
Immediately west of the plant is the Shippingport Atomic Power Station.
The design and construction of the plant will be performed by Stone & Webster Engineering Corporation under the direction of the applicant, the Duquesne Light Company." The nucicar steam supply systems will be supplied by Westinghouse.
A Preliminary Safety Analysis Report has been submitted in support of the application to show that the plant will be designed and constructed in a manner which will provide for safe and reliable operation.
Our review is based on the information pre-sented in the Preliminary Safety Analysis Report and Amendments, and is directed specifically towards an evaluation o.f the selsmic and structural design of Class I structures, systems, and components.
The list of re-ference documents upon which this review has been based is given at the end of this report.
DESCRIPTION OF FACILITY The Beaver Valley Plant site is located on gently sloping river terraces on the south bank of the Ohio River. The plant will be about 1000 ft southeast of the river; ground surface of the pla,nt will be about 40.f t above normal river level.
Steep bluf fs which compris'c the margins of the river valley rise to elevations several hundred feet above river level south and east of the site.
The site is located in an area of river de-posits which were removed for' construction of the plant.
Underlying these JOHN A. GLUMC & ASSOCIATES. ENGINEERG
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sedimentary deposits is a terrace of well consolidated alluvial gra-vels.
These graveis have a caximum depth of about 100 feet and rest directly on the sandstone and shale bedrock of Pennsylvanian age.
The bedrock is bedded horizontally and is essentially undeformed.
Foundation materials vary from gravelly soils to highly silty and claycy soils.
Gravelly soils are predominant on the upper bench where the reactor structure will be located and relatively weak silty and' clayey soils pre-dominate near the rivers edge where the cooling water intake f acilities will be located.
in the area intermediate between the upper bench and the river where some major structural components will be placed the uppermost soils will be excaveted and replaced with compacted fill.
The containment structure will be reinforced concrete cylinder and dome supported on a reinforced concrete foundation slab.
The interior of the
' tructure will be lined with a welded steel plate to ensure leak tightness.
The inside diameter of the containnent structure will be 126 ft.
The ver-tical wall thickness will be 4i f t and the dome thickness will be 21 f t.
The foundation slab thickness is 10 f t.
STRUCTURAL DESIGN CRITERI A AND LOADS Class I structures, systems, and equipment are those whose failure could cause or increase the severity of a loss-of-coolant accident.
They are designed to withstand the appropriate seismic loads simultaneously with other appilcable loads without loss of function.
Structure design loads are incr'ased by load factors based on the probability and conservatism e
of the predicted design loads. Yield capacity reduction factors are applied to the stresses allowed by the appilcable building codes.
The containment s tructure has been designed for a design pressure of 45 psig.
The maximum design temperature is 280 F.
The containment structure is designed for a 40 psf snow or ice load on the roof.
Loads due to flooding are a factor only during construction of the containment building.
JOHN A. BLUMC 8: ASSOCIATCS, CNGINECRS
Wind loads are to be determined for an 80 mph wind using the methods out-L lined by the Task Committee on Wind forces, ASCE Paper No. 3269 " Wind Forces on Structures". The structure will be designed for tornado Icading which corresponds to a design tornado with a 300 mph tangential velocity, a 60 mph forward velocity, and an atmospheric pressure drop of 3 psi.
Tor-nado generated missiles considered in the design will be among others, a 35 ft long utility pole at 150 mph.
ADEQUACY OF THE SEISMIC DESIGN CRITERI A We have reviewed the Preliminary Safety Analysis Report and Amendments No.
I through 15.
In addition, we have discussed the various aspects of the seismic design of.the plant with the applicant and ' members of the. staff of
' of the Division of Reactor Licensing at meetings on January 28, 1970 and barch18,1970. We have the following comments regarding the adequacy
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of the. seismic design criteria:
1.
An analysis of settlements in the founding soils has been presented by the appilcant and based upon this data the predicted settlements can be accomodated by suitable design procedures.
In addition, the appilcant has considered the possibility of densification of granular solls under vibratory loading due to earthquake and has Indicated that suitable precautions will be taken to prevent vibratory densi-fication.
2.
One of the areas of concern is possibility,of 11guefaction in those solls which consist predominantly of sand. The app 1Icant has shown that the natural in place density and grading of the sand are not within the range characteristic of sands which have been found to be subject to 11guefaction during earthquakes.
i 3.
The applicant has presented slope stability analyses developed for i
satur:ted conditions and under earthquake loading.
Based upon th:
-3 JOHN A. 91.UME & ASSOCIATC% ENGINCCl4G
data which was submitted the slope design should be adequate with it should respect to safety and integrity of Class I structures, be noted that saturation of soils can be achieved under conditions of thawing snow or prolonged heavy rainfall without necessity of flooding.
Therefore the assumption of saturated conditions is not overly conservative and combining this condition with the DBE is appropriate.
4.
Geologic reports state that the sedimentary strata beneath the site are very gently folded which Indicates that the region has probably not been subject to strong stresses for at least since the Pennsyl-vanlan period, and is not considered tectonically active.
The re-ports further indicate that no f aults are known to exist at the site
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or in the surrounding region.
The nearest fault is said to be loca-in a north-
.ted about 60 miles southeast of the plant site trending easterly direction.
5.
Historically, no earthquake of epicentral intensity greater than V has occurred within 80 miles of the site.
The nearest earthquake occu'rred at Sharon, Pa., about 40 miles north of the site, and had an epicentral intensity of MM til or IV.
It is estimated that the New' Madrid (1812) and Charleston (1886) earthquakes may have caused intensities of up to MM V at the site. The nearest areas of moderate selsmicity are near Attica, N.Y. and Anna, Chlo, both about 200 miles f rom the site; earthquakes in these areas have had a maximum Inten-sity of HM Vill, and apparently none of these has been perceptible at the site, it is estimated by the appilcant that the maximum bed-rock acceleration under DBE conditions would be 0.0359, which results in a peak ground surface acceleration of 0.125g for the Design Basis Earthquake (DBE).
A peak ground acceleration of 0.06g has been selec-ted for the Operating Basis Earthquake (OBE). We concur with the se-1ection of these ground accelerations for the DBE and OBE. We also concur with the response spectra for the DBE and OBE and the method in of application of these spectra as proposed by the applicant Appendix B, Amendment 15.
.k.
JOHN A. BLUMC at ASSOCIATCS, ENGINi~.8 ff 0
6.
The applicant has stated that he will use the response spectrum method of dynamic analysis for. Class I structures, piping, and equipment, and that discrete-mass multiple-degree-of-f reedom mathe-matical models will be developed for the structural system.
Possible vai'lations in foundation material properties will be considered in the selsmic analyses.
Structures will be analysed for response in both the horizontal and vertical directions, and horizontal and ver '
tical response spectra will be developed at the points of support of piping arid equipment. Ve concur in general with this approach.
The analytical techniques proposed by the appilcant are satisfactory and if properly implemented will result in a conservative design.
"7.
The appilcant has proposed to use approximate techniques for the development of response spectra to be used in the design of Class i piping and equipment supported within structures.,These methods
'are based on assumed motions at the support points of piping and equipment.
We have at several times expressed concern about the conservativeness of the proposed method as compared to the more comonly accepted time-history method.
The app 11 cant has presen-ted 'a comparison of the two methods in Amendment 15.
In these comparisons, the appilcant has introduced an "r" factor which was not in the method as originally proposed in the PSAR.
The com-parisons presented in Amendment 15 do not demonstrate that the proposed approximate method produces conservative results.
The applicant has also stated in AmenNnent 15 that he will develop comparisons of response spectra computed by his propnsed method and the time-history method for the 8eaver Valley Plant.
He has stated that these comparisons will be developed for the appropriate piping and equipment damping ratios and will utilize an input time-history that. produces the closest match to the response spectra presented in the PSAR.
The applicant has also implied, although it is not entirely clear, that the actual spectra utilized in the design will envelope the spectra produced by the, proposed rr.ctbod and the time-history method.
The applicant has not specifically stated what will be JOHN A. BLUME at ASSOCIATES. ENGINECf1S
donc in this regard for Class I structures other than the contain-ment structure; we feel this point should be clarified.
I in summary, the applicant has not yet demonstrated that the proposed method to develop response spectra at the support points approximate He has outlined a l
of Class I piping and equipment is conservative.
f program to substantiate the validity of his approach as applied to
)
Although certain details of this program the Beaver Valley Plant.
are not entirely clear, we feel that the general over-all program We recommend that the appilcant be required by the l
1s acceptable.
AEC to submit his demonstration of the validity of the proposed method to the AEC for review and approval prior to utilization of the response spectra curves in the final design.
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f CONCLUSIONS On the basis of the Information presented by the appilcant in the Preliminary Safety Analysis Report and Amendments, it is our opinion f
that,the selsmic design criteria and approach to seismic design as out' lined in the PSAR and Amendments 1 through 15, If properly implemented by the applicant, will result in a design that is adequate to resist the earthquake conditions postulated for the site.
JOHN A. BLUME f, ASSOCIATES, ENGINEERS,
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va Roland 'L. Sharpe Ga[risonKost MHN A. BLUME & ASSOCIATES. ENGINCCl4
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REFERENCES BEAVER VALLEY POWER STATION DUQUESNE LIGHT COMPANY (Docket No. 50-344)
Preliminary Safety Analysis Report, Volumes 1 through 4 Amendments No. 1 ghrough 15 Boring Logs e
O e
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JOHN A. SLUME & ASSOCIATE & ENGINECRC
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