ML20054G151
| ML20054G151 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 06/15/1982 |
| From: | Crutchfield D Office of Nuclear Reactor Regulation |
| To: | Fiedler P GENERAL PUBLIC UTILITIES CORP. |
| References | |
| TASK-02-04.F, TASK-2-4.F, TASK-RR LSO5-82-06-046, LSO5-82-6-46, NUDOCS 8206210177 | |
| Download: ML20054G151 (8) | |
Text
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t June 15, 1982 Ncket No. 50-219 "05-82-06-046 fu B. Fiedler
__,' resident and Director - Oyster Creek
.ar Creek Nuclear Generating Station Post Office Box 388 Forked River, New Jersey 08731
Dear Mr. Fiedler:
SUBJECT:
SEP SAFETY TOPIC II-4.F. SETTLE! TENT OF FOUNDATIONS AND BURIED EQUIPMENT - OYSTER CREEK NUCLEAR GENERATING STATION Enclosed is a copy of our evaluation for Systematic Evaluation Program Safety Topic II-4.F. Settlement of Foundations and Buried Equipment.
This assessment compares your site condition, as described in the docket and references with the criteria currently used by the staff for licensing new facilities.
Please inform us if your site condition differs from the licensing basis assumed in our assessment.
Our review of this topic is complete and this evaluation will be a basic input to the integrated safety assessment for your facility unless you identify changes needed to reflect the existing site conditionsat your facility. This topic assessment may be revised in the future if HRC criteria relating to this topic are modified before the integrated assessment is completed.
Sincerely, SNO usE (58 e
b** gll 3-Dennis 11. Crutchfield, Chief Operating Reactors Branch No. 5 Division of Licensing
Enclosure:
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Mr. P. B. Fiedler cc G. F. Trowbridge, Esquire Resident Inspector Shaw, Pittman, Potts and Trowbridge c/o U. S. NRC 1800 M Street', N. W.
Post Office Box 445 Washington, D. C.
20036 Forked River, New Jersey 08731 J. B. Lieberman, Esquire Commissioner Berlack, Israels & Lieberman New Jersey Department of Energy 26 Broadway 101 Commerce Street New York, New York 10004 Newark, New Jersey 07102-Ronald C. Haynes, Regional Administrator
, Nuclear Regulatory Commission, Region I 631 Park Avenue King of Prussia, Pennsyl.vania 19406
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J.. Knubel BWR Licensing Manager i
GPU Nuclear 100 Interplace Parkway Parsippany, NE., Jersey 07054
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Deputy Attorney General State of New Jersey Department of Law and Public Safety 36 West State Street - CN 112 Trenton,' New Jersey 08625 Mayor Lacey Township 818 Lacey Road Fo.rked River, New Jersey 08731 e-U. S. Environmental Protection Agency Region II Office ATTN:
Regional Radiation Representative 26 Federal Plaza New York, New York 10007 Licensing Supervisor Oyster Creek Nuclear Generating Station Post Office Box 388 Forked River, New Jersey 08731 e
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Systematic Evaluation Program Topic Assessment Topic:
II-4.F - Settlement of Structures and Buried Equipment Plant Name:
Oyster Creek Nuclear Power Plant Docket Number:
50-219 I.
INTRODUCTION This topic pertains to the Geotechnical Engineering Review of the subsurface materials and foundations to assess the static and seismically induced settlement of critical structures and buried equipment.
II.
REVIEW CRITERIA i
The current criteria for review of this topic are contained in NUREG-0800, Standard Review Plan Section 2.5.4, " Stability of Subsurface Materials and Foundations."
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III.
RELATED SAFETY TOPICS AND INTERFACES Geotechnical engineering aspects of slope stability are reviewed under topic II-4.D.
Other interface topics include II-4.E, " Dam Integrity;"
II-3.C, " Safe,ty-Related Water Supply (Ultimate Heat Sink)"; II-3.B.
" Flooding Potential and Protective Requirements"; III-6, " Seismic Design Considerations;" XVI, " Technical Specifications;" III-3.C, "In-Service Inspection of Water Control Structures;" III-3.A, " Effects of High Water Level on Structures;" and XI-3, " Station Service and Cooling Water Systems."
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IV.
REVIEW GUIDELINES In general, the review process is conducted in accordance with the procedures described in fiUREG-0800 Standard Review Plan Section 2.5.4.
The geotechnical engineering aspects of the design and as-constructed
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conditions of structures are reviewed and compared to current cr'iteria, and the safety significance of any differences is evaluated.
V.
TOPIC EVALUATION The Oyster Creek Nuclear Power Plant is located on the Atlantic Coastal Plain of'New Jersey approximately two miles inland from the Shore of 1
Barnegat Bay. The ground surface in the vicinity of the nuclear station is at about elevation +23 feet (MSL).
Subsurface Conditions Five subsurface investigations have been carried out within or in close proximity to the Oyster Creek site.
The results of the major boring program conducted in 1964 were mainly used for the settlement potential analyses of the preIent plant structures, since these borings are closest to the structures.
In all,14 borings were drilled to depths of as much as 150 feet below ground surface. Soil samples were obtained with the standard split spoon sampler.
Standard procedures were used except in a few isolated cases where the weight of *.ae hanmer was increased t'o 9
S j.
-3 300 lb and the hammer drop decreased to 20 in.
Between 1964 and 1970 borings were drilled for the proposed Oyster Creek Unit 2 and the proposed Forked River Unit 1, and in 1973-1974 for the'New Radwaste and Off-gas buildings at Oyster Creek Unit 1.
The various investigations at Oyster Creek indicated an essentially-uniform subsurface stratigraphy.
The specific formations encountered at the site consisted of five soil strata which are summarized below:
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Formation Average Thickness
- Soil Type and Elevation, ft 1.
Cape May 17 (el 23 to el 6)
Tan medium to fine sand, medium dense to dense.
2.
Upper Clay 17 (el 6 to el -11)
Gray organic clay with inclusions of fine sand, hard.
3.
Cohansey 65 (el -11 to el -76)
Yellow-brown or' tan medium to fine sand, dense to very dense.
4.
Lower Clay 8 (el -76 tc el -84)
Gray medium to fine sand with inclusion of gray organic clay 5.
Kirkwood Below el -84 Gray medium to fine sand Groundwater levels were found to be less than 10 feet below ground surface during the 1964 subsurface exploration.
The most recent (1973-1974) subsurface exploration indicated that the ground water level in the Cape May formation was perched at approximately el 12 ft.
- Ground surface elevation +23 feet (MSL)
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Foundations and Settlement' Observations The major Category 1 structures are supported by mat foundations bearing in the Cohansey Formation. These structures include the Reactor Building, the Vent Stack, the Intake and Discharge Structsres, the Circulating Water Tunnels and the Diesel Generator Building.
Standard Penetration Test (SPT) blow counts in the Cohansey vary from an average of 55 blows /
foot (el -11 to el -30) to an average of 100 blows / foot (el -30 to el -76).
Observed total settlements of the reactor building (foundation mat at el -29.5) have ranged from 2/3 to,3/4 inches, which compares well with the predicted settlement of less than one inch.
i Liquefaction and Seismic Settlement The postulated SSE ground acceleration for the Oyster Creek Nuclear Station is 0.165 g.
SPT blow counts in excess of 100 per foot for the saturated Cohansey sands below el -30 precludes liquefaction.
For the Cohansey sand above el -30, the liquefaction potential was evaluated by the Simplified Seed and Idriss Method and by a direct method that compares c.
the stresses induced by earthquake motions to the cyclic strength characteristics of the_ soil.
Both analyses indicated that the sands above el -30 would not liquefy for a peak ground acceleration of 0.229, which is higher than the postulated acceleration of 0.1659 for the Oyster Creek Station.
Seismic induced settlement would be negligible for these conditions.
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-5 Backfill and Buried Equipment Buried equipment (pipes, etc) is su'pported on compacted granular fill placed adjacent to structures.
Although no specifications, compaction methods and density requirements for.the fill are available for staff review, the staff was informed in conversations with the licensee's soils consultant, Woodward-Clyde associates, that, in all probability, excavated Cape May sand was used as fill and compacted to at least 75
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percent relative density.
The staff has no means to verify the placed density or the nature of the fill, although,an examination of surficial materials adjacent to structures at Oyster Creek, during the staff I
reviewer's site visit on May 7,1982, suggested that the fill is a medium to fine sand (averaging less than 12 percent passing the No. 200 sieve) with trace of gravel.
This type of material is amenable to compaction and a modest compactive effort would suffice to effect 75 percent relative density.
Because this fill is likely to be in the 75% relative density range, it is the staff's judgement-that there would b'e no settlement related loss of support for Category 1 piping founded on and in this fill under static conditions or during the SSE and thus such settlement sh'ould not pose a safety problem, VII.
CONCLUSIONS Based on the evidence obtained during the site visit and presented by the licensee, the staff concurs with the licensee's conclusion that:
a) Static total and differential settlement of Category 1 structures are small and were essentially complete soon after construction and should not pose a safety problem.
b)
Liquefaction of the Cohansey sand is sufficiently unlikely uhder the postulated SSE earthquake with a peak ground acceleration of 0.165 g.
VIII.
REFERENCES 1.
SEP Safety Topic Evaluation, Oyster Creek Nuclear Power Plant, Topic II-4.F - Settlement of Founda'tIons and Buried Equipment by JP&L, revised September 30, 1981 and submitted by letter from Mr. T. Nagai, JP&L to Mr. R. Fell, NRC, dated November 4,1981.
2.
Report, subject "Geotechnical Study, Proposed Radwaste and Off Gas Buildings, Cyster Creek Nuclear. Power Station", by Woodward-Moorehouse and Associates, Inc., dated February 4, 1975.
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" Report to Burns'and Roe on Foundation Investigation for the Oyster Creek Nuclear Power Plant - Unit No. 2," by A. & L. Casagrande, dated September 1968.
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