ML20052B680
| ML20052B680 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 04/22/1982 |
| From: | Counsil W NORTHEAST NUCLEAR ENERGY CO. |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20052B681 | List: |
| References | |
| TASK-02-03.B, TASK-2-3.B, TASK-RR B10468, NUDOCS 8205030445 | |
| Download: ML20052B680 (7) | |
Text
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7 Director of Nuclear Reactor Regulation
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T10C Attn:
Mr. Dennis M. Crutchfield, Chief h
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U. S. Nuclear Regulatory Commission Washington, D.C.
20555
References:
(1)
W. G. Counsil letter te D. M. Crutchfield, dated June 26, 1981.
(2)
W. G. Counsil letter to D. M. Crutchfield, dated November 19, 1981.
(3)
W. G. Counsil letter to D. M. Crutchfield, dated November 22, 1981.
Centlemen:
Millstone Nuclear Power Station, Unit No. 1 SEP Topic II-3.B, Flooding Potential and Protection Requirements In Reference (1), Northeast Nuclear Energy Company (NNECO) submitted the Safety Assessment Report (SAR) for SEP Topic II-3.B, Flooding Potential and Protection Requirements, for Millstone Unit No. 1.
Reference (2) was later docketed as an Addendum to Reference (1) in order to respond to questions posed by the Staff.
Subsequent to the docketing of References (1) and (2), the Staff again identified additional information required to complete their evaluation of this SEP topic.
In response to this request, NNECO is providing Attachment 1 as an Addendum to the SAR provided in Reference (1).
We trust the Staff will appropriately use this information to develop a Safety Evaluation Report for this SEP topic.
05T Very truly yours, g
NORTHEAST NUCLEAR ENERGY COMPANY
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W. G. Counsil Senior Vice President 3C 8205030%5 P
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Docket No. 50-245 Addendum to Safety Assessment Report SEP Topic II-3.B. Flooding Potential and Protection Requirements March, 1982
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TOPIC II-3.B FLOODING POTENTIAL AND PROTECTION REQUIREMENTS MILLSTONE UNIT I ADDENDUM The following has been compiled to address a staff request for additional information.
REQUEST What is the height above the roof of the curbs or parapets around the roofs of Unit 1 safety-related structures?
RESPONSE
The requested information is summarized in the attached Figure 1.
For additional details, refer to the following drawings included in the November 20, 1981 addendum to Topic II-3.A, (Reference 3) 25202-11020 Roof Level Plans, Architectural Plumbing 25202-11023, 11024 Wall Sections 25202-11026 Miscellaneous Details The following drawing is included with this submittal to supplement the above:
25202-11033 Miscellaneous Buildings, Architectural Plumbing REQUEST Design maximum rainfall rates used for building design are 3.00 inches in one hour and 7.10 inches in 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. Does this mean that roof drains will drcin 3 inches per hour or will ponding occur?
RESPONSE
From Figure 1, the largest value of roof drainage area per drain is 3,625 feet 2 Based on rainfall rate of 3 inches per hour, the resulting drain velocity can be calculated as follows:
Q = AV (3 inches / hour)(3,625 feet ) =
(2 inches)2 y 2
0.252 cfs = (0.0873 square feet) V V = 2.9 feet /second
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TOPIC II-3.B FLOODING POTENTIAL AND PROTECTION REQUIREMENTS r
MILLSTONE UNIT I l
ADDENDUM i
The following has been compiled to address a staff ~ request for additional
- information.
l REQUEST-I What is the height above the roof of the curbs or parapets around the roofs of Unit 1 safety-re'.ated structures?
RESPONSE
i The requested ~information is summarized in the attached Figure 1.
For additional details, refer to the following drawings included in the November 20, 1981 addendum to Topic II-3.A, (Reference 3);
25202-11020 Roof Level Plans, Architectural' Plumbing 25202-11023, 11024 Wall Sections 25202-11026 Miscellaneous Details l
The following drawing is included with this submittal to supplement the above:
25202-11033 Miscellaneous Buildings,-Architectural Plumbing l
REQUEST
]
Design maximum rainfall rates used for building design are 3.00 inches in one hour and 7.10 inches in 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. Does this mean that roof drains will drain 3 inches per hour or will ponding occur?
RESPONSE
3 FromFigurg1,thelargestvalueofroofdrainage-areaperdrainis 3,625 feet Based on rainfall rate of 3 inches per hour, the resulting drain velocity can be calculated as follows:
Q = AV (3 inches / hour)(3,625 feet ) = j]f (2 inches)2 y 0.252 cfs = (0.0873 square feet) V 17 = 2.9 feet /second 7
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TOPIC II-3.B FLOODING POTENTIAL AND PROTECTION REQUIREMENTS MILLSTONE UNIT I ADDENDUM PAGE 2 Due to the multiple drains and the low flow velocity in the drain system, NNECO concludes that the drains are appropriately sized and significant ponding will not occur. Accordingly, the Unit 1 roofs are adequately designed against maximum rainfall.
REQUEST Provide elevations of all road and railroad crown grades around Unit 1.
RESPONSE
The requested information is detailed on the following drawings in-cluded in the November 19, 1981 addendum to this topic:
25202-11055 Plant Area Grading and Drainage Plan 25202-11008 Entrance Railroad Switchyard Grading Profile Section 25202-11009 Plant Road Plan Section In addition, the following drawings are hereby submitted:
25202-10003 Plot Plan 25202-11007 Entrance Railroad Switchyard Grading Plan 25203-10008, Site Plan "Ae Built" Sheet 585 25203-11006 Railroad Plan 25203-11007 Railroad Profiles and Details REQUEST Specify Unit 2 plant grade, design basis rainfall, and elevations of any associated roads, railroads, and structures which might pond water against Unit 1 buildings.
RESPONSE
The influence of Unit 2 (and Unit 3) can best be depicted from the following drawings included in the November 20, 1981 addendum to Topic II-3A, Reference (2) and the November 19, 1981 addendum to this topic, Reference (3):
25212-11008, 11009 Finished Grading, Roads, and Walkways 25212-25001, 25002 Yard Storm and Sanitary Sewers
e TOPIC II-3.B FLOODING POTENTIAL AND PROTECTION REQUIREMENTS MILLSTONE UNIT I ADDENDUM PAGE 3 i
In addition, the following drawings are hereby submitted:
25212-11040 Station Plan 25203-10003 Plot Plan l
25203-11003 Paving, Drainage Plan and Details l
The Unit 2 plant design rainfal.1 was 2 inches per hour. Further
~ details are contained in Section 2.3.1.3 of the Millstone Unit 2 FSAR.
l REQUEST l
It is stated by the Licensee that construction of Units 2 and 3 im-proves the surface runoff situation at Unit 1 because they are at a i
higher elevation.than Unit 1 and would divert runoff originating from the north, east or west away from the plant. What prevents l
runoff originating from precipitation on the Unit 2 and 3 sites from flowing on to the lower Unit 1 site?
RESPONSE
l The objective of grading and drainage design for Units 2 and 3 was to establish a system to handle the runoff from the respective unit.
The Unit 2 and 3 drawings listed in the preceding requests detail the systems. Consideration of the interface between Units 2 and 1 is shown on-the following sketch:
25203-10008, Sheet 745 Drainage Plan--Area East Between Units 1 and 2 The combined system that has been inservice since the completion of Unit 2 has adequately diverted all storm runoff.
REQUEST Provide clear copies of NUSCO Drawing 25202-11005, Grading and Drainage Plan (Unit 1), the drawing referenced on the above drawing as drawing C-187763, and a drawing showing finished grading and drainage of Unit 2.
RESPONSE
Additional copies of the requested drawings are included. The requested Unit'2 drawings are listed in a preceding request of this addendum.
Li
FIGURE 1:
SUMMARY
OF HP1 ROOF DRAINAGE Number Drain Approx.
oE Size HP Roof Drainage Structure Area (FD Dralns (Inches)
{Ft)*
LP Roof
- N S
E W
Area / Drain TURBINE BUILDING Main Roof 85 x 300 8
4 105.46 104.75 107.17 107.17 107.17 107.17 3,188 ft H&V Area Rcof 85 x 100 6
4 77.13 76.67' 77.83 77.83 NA NA 1,417 Warehouse Roof 75 x 145 3
4 34.34 33.S5 NA 35.46 35.46 35.46 3,625 N-E Arec Roof 69 x 66 4
4 S4.54 S3.30 55.50 NA S5.50 NA 1,139 S-E Area Roof 146 x 66 8
4 54.50 S3.50 NA 55.50 55.50 NA 1,204 REACTOR BUILDING Reactor Bldg Roo'E 105 x 140 6
4 151.00 150.25 152.33 152.33 152.33 152.33 2,450 S-W Area Roof 35 x SS 1
4 S4.50 S4.50 NA 55.00 NA 55.50 1,925 RADWASTE/ CONTROL BLDG Control Roof 84 x 69 4
4 54.50 54.50 S5.50 NA 55.50 55.50 1,449 GAS TURBINE BLDG Bldg Roof
' 38 x 81 2
4 41.03 41.03 41.91 41.91 41.91 41.91 1,539 IHTAKE STRUCTURE Bldg Roof 71 x 59 3
4 42.00 41.75 42.83 42.83 42.83 42.83 1,396
- Elovation of roof steel or concrete roof slab (does not account for cnncrete fill, insulation, or buildup roofing)
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