ML13330A300
| ML13330A300 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 04/20/1981 |
| From: | Moody W SOUTHERN CALIFORNIA EDISON CO. |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML13317B393 | List: |
| References | |
| TASK-02-03.A, TASK-02-03.B, TASK-2-3.A, TASK-2-3.B, TASK-RR NUDOCS 8104270355 | |
| Download: ML13330A300 (9) | |
Text
Southern California Edison Company P. 0.
BOX 800 2244 WALNUT GROVE AVENUE ROSEMEAD, CALIFORNIA 91770 W. C. MOODY A
l 20 1981 TELEPHONES MANAGER, NUCLEAR LICENSING A pri (213) 572-1817 (213) 572-1806 Director of Nuclear Reactor Regulation Attention:
Mr. D. M. Crutchfield, Chief Operating Reactors Branch No. 5 Division of Licensing
-0 U.S. Nuclear Regulatory Commission Washington, D.C. 20555 C
Z Gentlemen:
Subject:
Docket No. 50-206 U1 SEP Topics II-3.A and II-3.B San Onofre Nuclear Generating Station Unit 1 Enclosed for your use in connection with the subject SEP topics is the following information:
- 1. Drawings showing the beach walkway which is currently under construction in front of the seawall.
5180940-0 Beach Walkway General Notes & Drawing List 5180941-0 Beach Walkway Permanent and Temporary Plan 5180942-0 Beach Walkway Details 5180943-0 Beach Walkway Sections and Details 5180944-0 Beach Walkway Sections and Details 5180945-A Beach Walkway Permanent Walkway Details
- 2. Information pertaining to the maximum ground water level at the San Onofre site. This information was previously provided to the NRC in connection with the structural audit of San Onofre Units 2 and 3.
If you have any questions on this information please let me know.
Sincerely, A3 Endlosures JJ 810,427035f
NRC STRUCTURAL AUDIT REQUEST ITMS INTAKE STRUCTURE AND BOX CONDUIT Item #2:
Provide basis for establishing the maximum ground water level used in determining hydrostatic pressures on structural walls.
Response
A number of observations for ground water level has been made at the sites for Unit 1 and Units 2 and 3 over the past 10 years. These observations were made during various investigations such as soil explorations, pumping tests for evaluating field permeability of native soils, installation of the Units 2 and 3 dewatering system and investigations during demobiliza tion of the Units 2 and 3 dewatering system. A summary of these observa tions is presented in Table 1. Figure 1 presents the locations of various observations points.
The data presented in Table 1 indicate a maximum value of +5.8 feet. Only a few of the measurements indicated a level above +5 feet and those were made on the dewatering wells or test piezo meters and may reflect transient conditions related to a rapid inflow of water occurring when dewatering was terminated. For this reason, and based on the majority of the data, it is concluded that elevation +5 feet represents a reasonable maximum for the ground water level at the site.
This conclusion is also consistent with areal observations as follows:
(1) ground water contours for typical high and low ground water conditions are presented in Figures 2.4-27 and 2.4-28 of the FSAR (presented as Figures 2 and 3 here for completeness) indicate a maximum ground water elevation of +5 feet in the immediate vicinity of the site; and (2) a
report by California Department of Water Resources (Reference 1) provides regional data indicating an average ground water elevation in the vicinity of the site is +5 feet.
Ground water sources for the general area of the site are described in Section 2.4.6.13 of the FSAR. Because the foundation soil at the site (San Mateo Sand) is free draining and because the site is adjacent to the ocean, the fluctuations in the ground water are primarily controlled by tidal fluctuations.
Further, because of the free draining nature of the foundation soils and the surface drainage facilities at the site, direct rainfall on the site is not expected to have an influence on the ground water level.
In view of the above information and the observed ground water levels in the various wells summarized in Table 1, it is concluded that an elevation of +5 feet represents a reasonable maximum level for the ground water at the plant site.
References
- 1. California Department of Water Resources, 1968, Reclamation of water from wastes - central San Diego County:
Bulletin 80-2.
TABLE 1
SUMMARY
OF GROUND WATER LEVEL OBSERVATIONS Elev. of Well/Boring Date of Observed Designation Observation Water Level Remarks Water Well #1 May 1967
+3.9 Well #1 through 5 are June 1967
+4.0 located in area of March 1970
+4.1 Unit 1 (see Figure 1)
Dec 1970
+3.9 Water Well #2 April 1967
+2.6 May 1967
+3.1 June 1967
+3.3 March 1970
+3.3 Dec 1970
+3.5 Water Well #3 April 1967
+3.0 May 1967
+3.3 June 1967
+3.5 March 1970
+3.7 Dec 1970
+3.7 Water Well #4 April 1967
+1.2 May 1967
+2.1 June 1967
+1.7 March 1970
+2.5 Dec 1970
+2.2 Water Well #5 April 1967
+0.8 D-M Boring #2 March 1970
+5.0 Soil boring.
Piezometer May 1974
+5.60*
Observation wells #1 Well #1 through 7 installed for pump tests.
The Piezometer May 1974
+3.09 observations repre Well #2 sent initial readings before pump tests.
Piezometer May 1974
+5.80*
Well #3 Piezometer May 1974
+5.24*
Test well.
Well #3A Piezometer May 1974
+5.60*
Well #4
Table 1 Page 2 Elev. of Well/Boring Date of Observed Designation Observation Water Level Remarks Riezometer May 1974
+5.76*
Well 15 Piezometer May 1974
+5.34*
Well 16 Piezometer May 1974
+5.47*
Well 17 Deep Well #1 July 1977
+4.5 Deep wells installed for dewatering system.
Deep Well #2 Aug 1977
+4.5 Deep Well 13 Nov 1977
+5.5 Deep Well 3A Sept 1977
+5.0 Deep Well #4 May 1976
-0.50**
Deep Well #5 April 1976 0.0**
Deep Well #6 July 1976
-1.5**
Deep Well #7 June 1976
-3.0**
Deep Well #8 June 1976
-3.0**
Deep Well #9 Nov 1976
-3.5**
Deep Well #10 July 1977
+4.5 Deep Well #11 July 1977
+2.5 Deep Well #12 July 1977
+2.5
- Values above Elev. +5 feet may be affected by testing operation (i.e., rapid water inflow after test covering a local high)
Readings represent maximum values monitored over a period from 1974 to 1977.
Low values may be related to dowatering from adjacent wells.
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