ML20136F638
| ML20136F638 | |
| Person / Time | |
|---|---|
| Site: | 05000000, Vogtle |
| Issue date: | 01/09/1985 |
| From: | Ballard R Office of Nuclear Reactor Regulation |
| To: | Adensam E Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML082840446 | List:
|
| References | |
| FOIA-84-663 NUDOCS 8501140182 | |
| Download: ML20136F638 (6) | |
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gj UNITED STATES A
F NUCLEAR REGULATORY COMMISSION Y
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E WASHINGTON, D. C. 20555 V
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0[b MEMORANDUM FOR: Elinor Adensam, Chief d
Licensing Branch #4
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Division of Licensing
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FROM:
Ronald L. Ballard, Chief Hydrologic & Environmental Engineering Branch Division of Engineering
SUBJECT:
HYDROLOGIC ENGINEERING SAFETY QUESTIONS FOR DRAFT SER OPEN ITEMS
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I'b Plant Name: Vogtle Electric Generating Plant Licensing Stage: OL iu'
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Docket Nos.:
50-424/425 g,n
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Attached are additional Hydrologic Engineering Safety Questions that cover (if' the open items and confirmatory issues discussed in our draft SER input.
This review was performed by Gary B. Staley of the Hydrologic Engineering Section, extension 28003.
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nald L. Ballard, Chief Hydrologic & Environmental Engineering Branch Division of Engineering
Attachment:
As stated cc:
W. Johnston
- 0. Parr M. Miller D. Chery J. Kane l
G. Staley l
E PilYoph 20H j
Vogtle Electric Generating Plant Hydrologic Engineering Safety Questions Docket Nos. 50-424/425 240.14 You have not provided an analysis of the design basis water level (s) for local PMP on the Vogtle site. Specifically, you have not provided the contributing drainage areas and peak dis-charges for sub areas nor any peak water surface elevations.
Our previous question 240.3 delineated very specific information that is required by the staff to facilitate an independent analysis of the design basis flood level as a result of local intense pre-cipitation (PMP) on the site area. Less than half of the specific information requested was provided. Specifically, you did not prd-vide any response to items B, C,- F, G and H and only partial response to item E of Question 240.3.
Listed below is a re-iteration of.
specific information that is required by the staff in order to per-form an independent evaluation of the effects of local PMP on the site area.
A.
Full size (unreduced) drawings for figure 2.4.1-2, Sheets 1
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and 2 that include the following information:
(1) Mark the outline of the entire contributing drainage area for the site drainage system and boundaries for all subbasins within the main drainage basin.
(2)
Elevations at each change in grade for all peripheral roads and railroads and all drainage ditches. Also pro-vide sufficient spot elevations on all flat or gently sloping. areas (mainplantarea,parkinglots, switchyard, etc.) such that the staff will be able to determine slopes or elevation limits.
(3) Arrows to indicate assumed flow paths for overland and ditch flow.
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e f (4) Locations of all culverts, bridges or other water control structures.
b (5)
Indicate all paved areas.
B.
Provide the drainage area, time of concentration, runoff coefficient and peak discharge for the Probable Maximum i
Precipitation (PMP) for each subbasin. Provide peak dis-charges for all ditches where they leave the plant vicinity.
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C.
For all culverts used for PHP' discharge, provide the type, shape and length of pipe, inlet and outlet invert elevations 4
and shape or typt of inlet.
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D.
Provide the design basis water surfa:e elevation for safety-l related structures as a result of PMP on the site area.
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The staff's request for additional information (Question 240.4)
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regarding differences in local PMP derived from HMR 51 and 52, is l
withdrawn. Recent internal NRC guidance (memorandum, H.R. Denton to l
V. Stello, Jr.,
Subject:
" Generic Requirements Regarding Design for Probable Maximum Precipitation," dated October 10,1984) allows the applicant to use pre-HMR 51 and 52 criteria, with the staff doing the 1
j initial evaluation using HMR 51 and 52 criteria. Then, only those l
facilities with demonstrable potential site flooding problems will be l
subject to the more rigorous evaluation by the applicant. Since the VEGP is well into the licensing schedule, it is prudent for the l_
applicant to expedite the transmittal of all the requested site l
drainage information so the staff can initiate'the independent l
' analysis for site drainage using HMR 51 and 52.
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l 1 240.15 Provide drawings (or reference existing drawings) that..show the roofs of safety related buildings and the locations -of' roof scuppers. Note on drawings all locations where scuppeTrs drain to adjoining roofs.
1 240.16 Your discussion in Section 9.2.5.6 regarding available basin j
water supply is not clear. Apparently the analyses presented in Section 9.2.5 was from the PSAR and tha basins provided a 26.7 day supply without makeup. Then apparently subsequent to the PSAR other changes occurred (diesel generator rating, fuel pit loading, " worst 30-day" meteorological data) which reduced the storage capability by 6.2 days or a net availability of 20.5 days.
The applicant next discusses conservations that can increase the capacity 2.7 days, but these are added onto the 26.7 day value rather than the 20.5 day corrected value to given an estimated l
capacity of 29.4 days (26.7 + 2.7) rather than 23.2 days l
(20.5 + 2.7).
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l The FSAR transient analysis for the UHS should include the correct heat loads, meteorology, etc.
If the applicant wishes to take l
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credit for conservatisms then they should be included in the
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analysis and appropriately noted in the discussion.
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Please provide a revised discussion for Section 9.2.5.6 (and else-t where as required) to clear.up the uncertainties noted above.
240.17 Tables 9.2.5-3 thru 9.2.5-7 show initial basin water temperatures
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of 88.5'F and 82.0*F for train A and B respectively.
Please explain l
this difference in starting temperatures.
240.18 Discuss your provisions for seepage analysis and testing of the l
cooling tower basins to insure that there will be no abnonnal l
losses from this source.
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, 6 240.19 Is any of the 3.65 x 10 gal / basin water supply for the VHS intended for use as a Seismic Category I water supply for tire protection? If it is, please discuss the ramification ~s on the 30-day UHS supply.
240.20 The design basis groundwater level for hydrostatic loading (no-combined seismic load) should approach a probable maximum value (i.e., a level that has virtually no chance of being exceeded).
The applicant may choose to use this one value for all loading
, conditions. However, the staff only requires that an approximate 25 year groundwater level be used with seismic loading conditions (SSE).
It is the staff's judgment that the groundwater data pre-sented in the FSAR is not high quality data and will not support a projection for a design basis groundwater level for~ hydrostatic loading.
The VEGP Draft Safety Evaluation Report discusses the need for a groundwater level monitoring program to provide data to sub-stantiate the design basis groundwater level for hydrostatic loading. Provide the details of this plan in the FSAR.
r Also provide a discussion in FSAR Section 2.4.12.4 that determines the groundwater levels at which structural distress would occur under both hydrostatic and dynamic loading conditions and include factors of safety, if any.
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We recommend that the applicant meet with the staff to discuss the details of the groundwater level monitoring program and to coordinate the Hydrologic Engineering and Geotechnical Engineering informational needs. Listed below for your considerat'fon are several items that would help to fulfill the Hydrologic Engineer-ing informational needs.
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i (1) Additional Wells - At least one well located in the vicinity of the mechanical draft cooling tower basins, screened in the surficial aquifer. Also, wells located in the plant backfill near safety-related buildings and in the undisturbed water table aquifer close to the power block area. Number and location to satisfy mutual needs or parties involved.
(2) Monitoring Frequency - Collection of a continuous record (well recorder) for at least one well in the plant backfill and one well in the undistrubed water table aquifer close to the power block area. All other wells should be read at least weekly.
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(3) Maintenance and/or Surveillance Program - Insure that all wells will be available and function properly for at least 5 years with an adequate maintenance program.
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